Dissertations / Theses on the topic 'Adenosine deaminase'

Thesis (MSc (Med)(Microbiology)) -- University of Limpopo, 2012.
Mycobacterium tuberculosis is the most common cause of death world-wide and its incidence has been steadily increasing, which is more evident when comparing the global tuberculosis (T8) incidence of 9.24 million in 2006 to 9.27 million cases in 2007. African countries are the second most affected by the epidemic and South Africa is among the 22 highest burden countries most affected by T8 with a very high number of cases relative to the total population. The early diagnosis of tuberculosis and screening of contacts is the cornerstone for controlling spread of active T8 infection. T8 diagnosis becomes even more challenging in patients with immunosuppression (for example in human immunodeficiency virus (HIV) infected), in the case of latent infection and extra pulmonary T8 such as pleural T8. The definitive diagnosis of pleural T8 depends on the demonstration of M. tuberculosis in sputum, pleural fluid and pleural biopsy. Although acid fast bacilli (AF8) microscopy is a rapid, inexpensive and relatively simple method, it has low sensitivity. The culture method is more sensitive than AF8 microscopy, detecting 25-37% of all pleural tuberculosis cases however it takes 4 to 8 weeks for a visible growth on a solid medium. Therefore it is important to find a rapid and reliable test for the diagnosis of pleural T8 particularly in developing countries such as South Africa where there is a high T8 incidence and HIV infection rate.

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The purinergic system is known to be an important signaling pathway in different tissues. Among the components of this system have adenosine, a modulator of central nervous, circulatory and immune systems. The concentration of adenosine in the host is controlled by the enzyme adenosine deaminase (ADA), present in tissues, cells and fluids. As a result, the objectives of this study were (1) to determine the ADA activity in Trypanosoma evansi, (2) evaluate the activity of ADA in serum, erythrocytes, lymphocytes and brain of infected rats, and (3) determine the concentration of nucleotides and nucleosides in serum and cerebral cortex of rats infected with T. evansi. In the first study two mice were infected with T. evansi. When these animals showed high parasitemia (±108 parasites/uL) was performed with blood collection and separation of trypomastigotes by DEAE-cellulose column for performing the assays. Spectrometry was performed by the biochemical detection of ADA in the form trypomastigotes of T. evansi. In a second study, we used 39 rats divided into three groups: group A and B (infected) and group C (C1 and C2 control group) Samples of blood and brain samples were collected on day 4 PI (A and C1) and 20 PI (B and C2). From the blood (with anticoagulant) were separated lymphocytes and erythrocytes for measurement of ADA activity, since the serum was obtained from blood samples stored in tubes without anticoagulant. The brain was separated into cerebellum, cerebral cortex, hippocampus and striatum to evaluate the ADA activity in each structure. Decrease of ADA activity in serum and erythrocytes in rats infected with T. evansi when compared not-infected (P<0.05). ADA activity in lymphocytes was decreased at day 4 PI and increased in day 20 PI. There was no difference in ADA activity in the cerebellum. In the cerebral cortex caused a reduction of ADA activity on days 4 and 20 PI. Decrease of ADA activity in hippocampus and striatum in the day 4 and day 20 PI, respectively. In a third study, 24 rats were used, 12 used as a negative control and 12 infected with T. evansi. On day 4 (n = 6 per group) and 20 PI (n = 6 per group) were performed to obtain blood samples of serum and cerebral cortex for analysis. The samples were prepared for quantification of ATP, ADP, AMP and adenosine. This study found increased concentrations of ATP, AMP and adenosine in the brain and serum of rats infected with T. evansi in both periods, except that the levels of adenosine decreased on day 4 PI. The ADP concentration did not change in this study. Therefore, the infection by T. evansi purinergic system components can be changed, may be involved in immune response, in anemia and neurological signs.
O sistema purinérgico é conhecido por ser uma via de sinalização importante em diversos tecidos. Entre os componentes desse sistema destacamos a adenosina, um modulador do sistema nervoso central, circulatório e imunológico. A concentração de adenosina no hospedeiro é controlada pela enzima adenosina deaminase (ADA), presentes em tecidos, células e fluidos. Em virtude disso, os objetivos deste estudo foram (1) determinar a atividade da ADA no Trypanosoma evansi; (2) avaliar a atividade da ADA no soro, eritrócitos, linfócitos e encéfalo e (3) determinar a concentração de nucleotídeos e nucleosideos no soro e córtex cerebral de ratos infectados com T. evansi. Para um primeiro estudo foram infectados dois camundongos com T. evansi. Quando estes animais apresentavam elevada parasitemia (±108 parasito/μL) foi realizada a coleta de sangue e separação dos flagelados por coluna de DEAE-celulose, a fim realização dos ensaios enzimáticos no parasito. Atividade da ADA nas formas trypomastigotas de T. evansi foi determinada por espectofotometria. Em um segundo estudo foi utilizado 39 ratos, divididos em três grupos: grupo A e B (infectado) e grupo C (C1 e C2/controle). Amostras de sangue e encéfalo foram colhidas nos dias 4 pós-infecção (PI) (grupos A e C1) e 20 PI (grupos B e C2). A partir do sangue total colhido com anticoagulante foram separados os linfócitos e eritrócitos para mensuração da atividade da ADA, já o soro foi obtido de amostras de sangue armazenadas em tubos sem anticoagulante. O encéfalo foi separado em cerebelo, córtex cerebral, hipocampo e estriado para avaliar a atividade da ADA em cada estrutura. Então, observou-se redução da atividade de ADA no soro e eritrócitos em ratos infectados com T. evansi em comparação com não-infectados (P <0,05). A atividade de ADA em linfócitos estava diminuída no dia 4 PI e aumentou no dia 20 PI. Não houve diferença da ADA no cerebelo. No córtex cerebral, no hipocampo e estriado ocorreu redução da atividade da ADA nos dia 4 e 20 PI, respectivamente. Em todas as estruturas do encéfalo foi detectada a presença do parasito por PCR. Em um terceiro estudo foram utilizados 24 ratos, sendo 12 controles negativos e outros 12 infectados com T. evansi. Nos dias 4 (n=6 por grupo) e 20 (n=6 por grupo) foram realizadas as coletas de sangue para obtenção do soro e amostras do córtex cerebral para mensuração dos níveis de ATP, ADP, AMP e adenosina. Neste estudo, foi constatado aumento das concentrações de ATP, AMP e adenosina no encéfalo e soro de ratos infectados com T. evansi nos dois períodos avaliados, com exceção dos níveis de adenosina que reduziram no dia 4 PI. Não houve alteração na concentração de ADP. Portanto, na infecção por T. evansi os componentes do sistema purinérgico pode ser alterados, podendo estar envolvido na resposta imunológica, na anemia e nos sinais neurológicos.

Na Anemia Falciforme em situações de baixa tensão de oxigênio, a hemoglobina mutante S (HbS) sofre polimerização promovendo a falcização das hemácias, que podem aderir ao endotélio vascular, causando a oclusão de vasos (VO) e isquemia tecidual (crises dolorosas) que caracterizam o quadro clínico da doença. Além disso, os pacientes falciformes apresentam outras manifestações clínicas como o priapismo, alterações ósseas, certas complicações pulmonares entre outros. Além das células eritróides, células endoteliais, leucócitos e plaquetas também desempenham um papel fundamental na fisiopatologia da anemia falciforme. A hidroxiuréia (HU), na anemia falciforme, aumenta a produção de hemoglobina fetal (HbF) em células eritróides, reduzindo a polimerização da HbS, diminuindo os sintomas clínicos dos pacientes. O aumento da HbF, no entanto, não implica necessariamente na melhora clínica, indicando desta forma a potencial ação da HU sobre outros processos. Estudos recentes vêm relacionando priapismo e asma com elevados níveis de adenosina. Devido a esta importância da adenosina relacionada a patologias comuns a AF, tivemos como objetivo identificar polimorfismos em genes de receptores de adenosina e na adenosina deaminase e verificar a possível associação entre as manifestações clínicas, além de investigar o papel da HU na modulação de marcadores envolvido na síntese e degradação da adenosina. Foram analisados diversos sítios polimórficos nos genes que codificam ADORA1, ADORA 2b, ADORA 3 e ADA, seguindo com a genotipagem em pacientes com AF, comparando afetados e não afetados. Em adição foi avaliada a expressão diferencial de mRNA de ADA pela HU em monócitos destes pacientes, comparando tratados e não tratados e também avaliamos por citometria de fluxo a modulação de marcadores de superfície CD39, CD73 e CD26, pela HU. As análises estatísticas foram realizadas utilizando os softwares GenePop 3.4 para análises de associação, cálculo do HWE, GraphPad Prism 5, Arlequin para identificação de desequilíbrio de ligação, haplótipos, heterozigozidade e SAS 9.13 para associação dos haplótipos as características. Os resultados mostraram que os pacientes sob tratamento com HU apresentaram um aumento da expressão de mRNA de ADA, aumento da expressão de CD26 em monócitos e diminuição de CD39 em linfócitos. Sem alterações significativas em relação a CD73. Encontramos também um aumento da freqüência do alelo T do SNP (rs1685103) presente no gene de ADORA 1 associado com pacientes afetados com síndrome torácica aguda. Apesar de não ter sido estatisticamente significante, concorda com dados da literatura. No gene ADORA 2B, verificamos associação do SNP 1007 C>T no desenvolvimento de STA indicando o alelo T como fator de risco e o alelo C para alterações ósseas. Para o SNP 968 G>T houve associação com alterações ósseas. Na análise haplotípica entre os SNPs 968 G>T e 1007 C>T encontramos associação dos haplótipos ht2 e ht3 com STA, como fator de risco, ht2 para hipertensão pulmonar. ht1 para priapismo, alterações ósseas e estenose/AVC. Os haplótipos formados pelos três SNPs 968 G>T, 1007 C>T e rs16851030, encontramos associação entre ht1, ht3 e ht4 entre os afetados com priapismo, caracterizando-o como haplótipo de risco e também ht1 e ht6 associados à estenose/AVC. Concluímos, que a hidroxiuréia participa na modulação da expressão da adenosina deaminase, de CD26 em monócitos e CD39 em linfócitos. Além disso, mostrou-se a importância de sítios polimórfico presente no gene ADORA 2B e ADORA1 envolvido na fisiopatologia das manifestações clínicas da doença falciforme. Associações dos SNPs em ADORA 1 e ADA, devem ser melhor estudados em um número maior de pacientes. A determinação destes polimorfismos associados com diferentes características clínicas pode levar a um melhor entendimento dos processos fisiopatológicos da anemia falciforme, levando à identificação de pacientes de risco, possibilitando um manejamento racional dos mesmos, em termos de cuidados específicos, ou mesmo à determinação de alvos para o desenvolvimento de terapias alternativas.
In sickle cell disease in low oxygen tension, mutant hemoglobin S (HbS) undergoes polymerization promoting sickling of red blood cells that can adhere to vascular endothelium, causing vessel occlusion (VO) and tissue ischemia (painful crises) that characterize the clinical disease. In addition, sickle cell patients have other clinical manifestations such as priapism, bone disorders, certain pulmonary complications among others. In addition to the erythroid cells, endothelial cells, white cells and platelets also play a key role in the pathophysiology of sickle cell anemia. Hydroxyurea (HU) in sickle cell anemia, increases the production of fetal hemoglobin (HbF) in erythroid cells, reducing the HbS polymerization, reducing the clinical symptoms of patients. The increase in HbF, however, does not necessarily imply clinical improvement, thus indicating the potential effects of HU on other processes. Recent studies relating asthma and priapism with high levels of adenosine. Due to this importance of adenosine-related pathologies common to AF, we aimed to identify gene polymorphisms in adenosine receptors and adenosine deaminase and verify the possible association between clinical manifestations, and to investigate the role of HU in the modulation of markers involved synthesis and degradation of adenosine. We analyzed several polymorphic sites in genes that encode ADORA1, ADORA 2b, 3 and ADORA ADA, according to the genotype in patients with AF, comparing affected and unaffected. In addition we assessed the differential expression of ADA mRNA by HU in monocytes of these patients, comparing treated and untreated, and also evaluated by flow cytometry modulation of surface markers CD39, CD73 and CD26 by HU. Statistical analysis was performed using the software GenePop 3.4 for association analysis, calculation of HWE, GraphPad Prism 5, Arlequin for identification of linkage disequilibrium, haplotypes, heterozygosity and SAS 9.13 for association of haplotypes features. The results showed that patients treated with HU showed an increase in mRNA expression of ADA, increased expression of CD26 on monocytes and decreased CD39 on lymphocytes. No significant changes in relation to CD73. We also found an increased frequency of allele T (SNP rs1685103) present in a gene associated with ADORA affected patients with acute chest syndrome. Although not statistically significant, agrees with literature data. ADORA 2B gene, we found association of the SNP 1007 C> T in the development of STA indicating the T allele as a risk factor for the C allele and bone changes. For the SNP 968 G> T was associated with bone disorders. In haplotype analysis between SNPs 968 G> T and 1007 C> T found association of haplotypes ht2 and HT3 with STA as a risk factor for pulmonary hypertension ht2. ht1 for priapism, stenosis and bone disorders / stroke. The three haplotypes formed by SNPs 968 G> T, 1007 C> T and rs16851030, we found association between ht1, HT3 and HT4 among those affected with priapism, characterizing it as a risk haplotype and also ht1 ht6 associated with renal and / AVC. We conclude that hydroxyurea participates in modulating the expression of adenosine deaminase of CD26 on monocytes and CD39 on lymphocytes. Moreover, he showed the importance of polymorphic sites in this gene and ADORA 2B ADORA1 involved in the pathophysiology of clinical manifestations of sickle cell disease. Associations of SNPs in ADORA 1 and ADA should be better studied in a larger number of patients. The determination of these polymorphisms associated with different clinical characteristics can lead to a better understanding of the pathophysiological processes of sickle cell anemia, leading to the identification of patients at risk, enabling a rational handling of the same in terms of specific care, or even the determination of targets for the development of alternative therapies.

Adenosine deaminase (ADA) severe combined immunodeficiency (SCED) is a life-threatening condition resulting from lack of the ADA enzyme. Consequences include immunodeficiency and non-immunological symptoms such as neurological abnormalities. Bone marrow transplantation (BMT) from a haploidentical donor usually results in complete restoration of immune function. However, the majority of patients do not have a matched donor and are therefore treated with enzyme replacement therapy (PEG-ADA). This treatment is not always fully effective, it is expensive and needs to be administered throughout life. Gene therapy is an alternative treatment, and previous trials for ADA deficiency have shown that it can significantly improve immunological function. Immune recovery was assessed in three ADA-SCID patients treated with PEG-ADA by analysis of lymphocyte counts and emergence of naive T cells. One patient was not responding well to PEG-ADA and was enrolled in a Phase I clinical gene therapy trial. A gammaretroviral vector encoding ADA was constructed and tested extensively on cell lines and patient cells and a CD34+ cell transduction protocol was optimised. The gene therapy procedure was based on previous successful trials, and involved withdrawal of PEG-ADA prior to treatment to provide selective growth advantage for transduced cells, and mild conditioning to encourage engraftment. Assessments of immune function were then performed in a similar manner to patients treated with PEG-AD A. Recent evidence from studies of ADA deficiency indicates that it is a multi-organ disease. However, gene therapy using CD34+ cells may only correct the immunodeficiency without ameliorating non-immunological symptoms. Hence, studies were performed to develop systemic gene therapy for ADA-SCID, involving the use of CD34+ cells and mesenchymal stem cells (MSCs). MSCs were isolated from bone marrow, and their multipotential nature was assessed prior to and following gene transfer using a cloned ADA lentiviral vector. Transduced MSCs maintained their ability to undergo differentiation and transgene expression was not affected by this. These clinical and preclinical in vitro studies demonstrate that gene therapy holds therapeutic potential for treatment of ADA-SCID.

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Nucleotide- and nucleoside-degrading enzymes are present in the surface of platelets, blood cells involved in clotting disturbances of Trypanosoma evansi-infected animals. Thus, this study was aimed at evaluating the activity of the enzymes NTPDase, 5 - nucleotidase and adenosine deaminase in platelets of rats experimentally infected by T. evansi. Animals were divided into four groups, according to the degree of parasitemia. Samples were collected at days 3 (group A: at the beginning of parasitemia), 5 (group B: high parasitemia) and 15 (group C: chronic infection). Group D (control group) was composed of non-infected animals. Blood samples with citrate as the anticoagulant were collected and used for platelet separation and enzymatic assays. NTPDase, 5 - nucleotidase and adenosine deaminase (ADA) activities were decreased (p<0.05) in platelets from rats of groups A and B, when compared to the control group. In group C, only NTPDase and 5 -nucleoside activities were decreased (p<0.001), observed by ADP and AMP hydrolysis. The correlation between platelet count and nucleotide and nucleoside hydrolysis was positive and statistically significant (p<0.05) in groups A and B. Platelet aggregation of all infected groups was decreased in comparison to the control group (p<0.05). Based upon the results, it is concluded that the alterations observed in the activity of the enzymes NTPDase, 5 -nucleotidase and adenosine deaminase in platelets of T. evansi-infected animals might be related to thrombocytopenia.
Nucleotide- and nucleoside-degrading enzymes are present in the surface of platelets, blood cells involved in clotting disturbances of Trypanosoma evansi-infected animals. Thus, this study was aimed at evaluating the activity of the enzymes NTPDase, 5 - nucleotidase and adenosine deaminase in platelets of rats experimentally infected by T. evansi. Animals were divided into four groups, according to the degree of parasitemia. Samples were collected at days 3 (group A: at the beginning of parasitemia), 5 (group B: high parasitemia) and 15 (group C: chronic infection). Group D (control group) was composed of non-infected animals. Blood samples with citrate as the anticoagulant were collected and used for platelet separation and enzymatic assays. NTPDase, 5 - nucleotidase and adenosine deaminase (ADA) activities were decreased (p<0.05) in platelets from rats of groups A and B, when compared to the control group. In group C, only NTPDase and 5 -nucleoside activities were decreased (p<0.001), observed by ADP and AMP hydrolysis. The correlation between platelet count and nucleotide and nucleoside hydrolysis was positive and statistically significant (p<0.05) in groups A and B. Platelet aggregation of all infected groups was decreased in comparison to the control group (p<0.05). Based upon the results, it is concluded that the alterations observed in the activity of the enzymes NTPDase, 5 -nucleotidase and adenosine deaminase in platelets of T. evansi-infected animals might be related to thrombocytopenia.

Adenosine deaminase acting on transfer RNA (ADAT) is a human heterodimeric enzyme that catalyzes the deamination of adenosine (A) to inosine (I) at the first position of the anticodon of transfer RNAs (tRNAs) (position 34, or wobble position); one of the few essential post-transcriptional modifications on tRNAs (1-5). Inosine 34 allows the recognition of three different nucleotides: cytidine, uridine and adenosine, at the third position of the codon, thus increasing the decoding capacity of tRNAs to more than one messenger RNA (mRNA) codon (adenosine 34 can in principle only pair with codons with uridine at the third position) (6, 7). This alters the tRNA pool available for each codon and it has been proved to align the correlation between codon usage and tRNA gene copy number (8). It has also been suggested to improve fidelity and efficiency of translation (8, 9), especially for mRNAs enriched in codons translated by modified tRNAs (10, 11). Monitoring ADAT-mediated deamination is crucial for the characterization of the enzyme in terms of activity, substrates, regulation, as well as for drug discovery purposes. However, this analysis is often challenging, laborious and lacks quantitativeness. We developed an in vitro deamination assay based on restriction fragment length polymorphism (RFLP) analyses to monitor ADAT activity in an efficient, cost-effective, and semiquantitative manner (12). To overcome a limitation of the method being the need of reverse transcription and amplification of the tRNA, we designed a direct method to quantify I34 formation in vitro using the first fluorescent analogs of nucleic acids that have been reported to undergo enzymatic deaminations (13-15). ADAT has been conserved over the evolution with the acquisition of multi-substrate specificity. Whereas its bacterial homolog TadA deaminates exclusively tRNAArg (2), the human enzyme deaminates eight different tRNAs (3, 16). However, the mechanisms that drove this evolution remain unknown. While the substrate recognition in TadA has been well studied, in the eukaryotic ADAT is poorly understood. Through in vitro enzymatic activity assays with different variants of tRNAArg and tRNAAla, we elucidated the most important features for efficient A34-to-I34 conversion and characterized the substrate recognition of the human enzyme. We also proposed a new potential mechanism of control of ADAT deamination activity by human tRNA-derived fragments, which provides new insights into the regulation of ADAT function and may open a door for the development of new strategies to modulate ADAT activity. A missense mutation (V128M) in one of the two subunits of the human ADAT enzyme causes intellectual disability and strabismus, but the molecular bases of the pathology are unknown (17, 18). We characterized human ADAT in terms of kinetics and structure, and investigated the effect of the V128M mutation. We found that this substitution decreases ADAT deamination activity, and severely affects the stability of the quaternary structure of the enzyme. In this regard, we discovered small molecules with the ability to activate the enzyme, which could potentially recover the defective tRNA editing caused by the mutation. References 1. Gerber AP, Keller W. An adenosine deaminase that generates inosine at the wobble position of tRNAs. Science. 1999;286(5442):1146-9. Epub 1999/11/05. 2. Wolf J, Gerber AP, Keller W. tadA, an essential tRNA-specific adenosine deaminase from Escherichia coli. The EMBO journal. 2002;21(14):3841-51. Epub 2002/07/12. 3. Torres AG, Pineyro D, Rodriguez-Escriba M, Camacho N, Reina O, Saint-Leger A, et al. Inosine modifications in human tRNAs are incorporated at the precursor tRNA level. Nucleic acids research. 2015;43(10):5145-57. Epub 2015/04/29. 4. Zhou W, Karcher D, Bock R. Identification of enzymes for adenosine-to-inosine editing and discovery of cytidine-to-uridine editing in nucleus-encoded transfer RNAs of Arabidopsis. Plant physiology. 2014;166(4):1985-97. Epub 2014/10/16. 5. Tsutsumi S, Sugiura R, Ma Y, Tokuoka H, Ohta K, Ohte R, et al. Wobble inosine tRNA modification is essential to cell cycle progression in G(1)/S and G(2)/M transitions in fission yeast. J Biol Chem. 2007;282(46):33459-65. Epub 2007/09/19. 6. Crick FH. Codon--anticodon pairing: the wobble hypothesis. Journal of molecular biology. 1966;19(2):548-55. Epub 1966/08/01. 7. Torres AG, Pineyro D, Filonava L, Stracker TH, Batlle E, Ribas de Pouplana L. A-to-I editing on tRNAs: biochemical, biological and evolutionary implications. FEBS Lett. 2014;588(23):4279-86. Epub 2014/09/30. 8. Novoa EM, Pavon-Eternod M, Pan T, Ribas de Pouplana L. A role for tRNA modifications in genome structure and codon usage. Cell. 2012;149(1):202-13. Epub 2012/04/03. 9. Schaub M, Keller W. RNA editing by adenosine deaminases generates RNA and protein diversity. Biochimie. 2002;84(8):791-803. Epub 2002/11/30. 10. Rafels-Ybern A, Attolini CS, Ribas de Pouplana L. Distribution of ADAT-Dependent Codons in the Human Transcriptome. International journal of molecular sciences. 2015;16(8):17303- 14. Epub 2015/08/01. 11. Rafels-Ybern A, Torres AG, Grau-Bove X, Ruiz-Trillo I, de Pouplana LR. Codon adaptation to tRNAs with Inosine modification at position 34 is widespread among Eukaryotes and present in two Bacterial phyla. RNA biology. 2017:0. Epub 2017/09/08. 12. Wulff TF, Arguello RJ, Molina Jordan M, Roura Frigole H, Hauquier G, Filonava L, et al. Detection of a Subset of Posttranscriptional Transfer RNA Modifications in Vivo with a Restriction Fragment Length Polymorphism-Based Method. Biochemistry. 2017;56(31):4029-38. Epub 2017/07/14. 13. Sinkeldam RW, McCoy LS, Shin D, Tor Y. Enzymatic interconversion of isomorphic fluorescent nucleosides: adenosine deaminase transforms an adenosine analogue into an inosine analogue. Angew Chem Int Ed Engl. 2013;52(52):14026-30. Epub 2013/11/30. 14. McCoy LS, Shin D, Tor Y. Isomorphic emissive GTP surrogate facilitates initiation and elongation of in vitro transcription reactions. Journal of the American Chemical Society. 2014;136(43):15176-84. Epub 2014/09/26. 15. Rovira AR, Fin A, Tor Y. Chemical Mutagenesis of an Emissive RNA Alphabet. J Am Chem Soc. 2015;137(46):14602-5. Epub 2015/11/03. 16. Juhling F, Morl M, Hartmann RK, Sprinzl M, Stadler PF, Putz J. tRNAdb 2009: compilation of tRNA sequences and tRNA genes. Nucleic acids research. 2009;37(Database issue):D159-62. Epub 2008/10/30. 17. Alazami AM, Hijazi H, Al-Dosari MS, Shaheen R, Hashem A, Aldahmesh MA, et al. Mutation in ADAT3, encoding adenosine deaminase acting on transfer RNA, causes intellectual disability and strabismus. Journal of medical genetics. 2013;50(7):425-30. Epub 2013/04/27. 18. El-Hattab AW, Saleh MA, Hashem A, Al-Owain M, Asmari AA, Rabei H, et al. ADAT3- related intellectual disability: Further delineation of the phenotype. American journal of medical genetics Part A. 2016;170A(5):1142-7. Epub 2016/02/05.
L’adenosina deaminasa específica per RNA de transferència (ADAT) és un enzim humà heterodimèric que catalitza la reacció de deaminació de l’adenosina (A) a inosina (I) a la primera posició de l’anticodó de RNAs de transferència (tRNAs) (també anomenada posició 34 o posició de balanceig); una de les poques modificacions post-transcripcionals essencials en tRNAs (1-5). La inosina 34 permet el reconeixement de tres nucleòtids diferents: citidina, uridina i adenosina, a la tercera posició del codó, augmentant per tant la capacitat de descodificació dels tRNAs a més d’un codó en l’RNA missatger (mRNA) (l’adenosina 34 en principi únicament pot aparellar-se amb uridina en la tercera posició) (6, 7). Això altera els nivells de tRNAs disponibles per cada codó i s’ha demostrat que alinea la correlació entre l’ús de codons i número de còpies gèniques de cada tRNA (8). També s’ha suggerit que millora la fidelitat i eficiència de la traducció (8, 9), especialment per mRNAs enriquits en codons traduïts per tRNA modificats (10, 11). Monitoritzar la deaminació produïda per ADAT és clau per la caracterització de l’enzim en termes d’activitat, substrats, regulació, així com també pel disseny de fàrmacs. No obstant, aquest anàlisi és sovint complex, laboriós i poc quantitatiu. Per això, hem desenvolupat un assaig de deaminació in vitro basat en el polimorfisme de longitud dels fragments de restricció (RFLP) amb el propòsit de monitoritzar l’activitat d’ADAT de manera eficient, cost-efectiva i semiquantitativa (12). Per superar una limitació del mètode essent la necessitat de transcripció reversa i amplificació del tRNA, hem dissenyat un mètode directe per quantificar la formació d’I34 in vitro utilitzant els primers anàlegs fluorescents d’àcids nucleics que són substrats de deaminacions enzimàtiques descrits fins al moment (13-15). ADAT ha estat conservat en l’evolució amb l’adquisició de multi-especificitat de substrat. Mentre que el seu homòleg bacterià TadA deamina exclusivament tRNAArg (2), l’enzim humà deamina vuit tRNAs diferents (3, 16). Tot i així, els mecanismes que van conduir a aquesta evolució romanen desconeguts. Mentre que el reconeixement de substrat en TadA es coneix bé, en ADAT eucariòtic ha estat poc estudiat. A través d’assajos enzimàtics in vitro amb diferents variants de tRNAArg i tRNAAla, hem elucidat els trets més importants per a una conversió eficient d’A34 a I34 i hem caracteritzat el reconeixement de substrat per part de l’enzim humà. També proposem un nou potencial mecanisme de control de l’activitat d’ADAT per part de fragments derivats de tRNAs humans, el qual ofereix noves perspectives en la regulació de la funció d’ADAT i que pot obrir la porta al desenvolupament de noves estratègies per modular-ne l’activitat. Una mutació sense sentit (V128M) en una de les dues subunitats en l’enzim ADAT humà s’ha associat a retard mental i estrabisme, encara que les bases moleculars de la patologia es desconeixen (17, 18). Hem caracteritzat ADAT humà en termes de cinètica enzimàtica i estructura, i n’hem investigat l’efecte de la mutació V128M. Hem descobert que la substitució de valina 128 per metionina redueix l’activitat deaminatòria d’ADAT i que altera severament l’estabilitat de l’estructura quaternària de l’enzim. En aquest aspecte, hem descobert molècules amb l’habilitat d’activar l’enzim, la qual cosa podria revertir potencialment la reducció en l’activitat enzimàtica causada per la mutació. References 1. Gerber AP, Keller W. An adenosine deaminase that generates inosine at the wobble position of tRNAs. Science. 1999;286(5442):1146-9. Epub 1999/11/05. 2. Wolf J, Gerber AP, Keller W. tadA, an essential tRNA-specific adenosine deaminase from Escherichia coli. The EMBO journal. 2002;21(14):3841-51. Epub 2002/07/12. 3. Torres AG, Pineyro D, Rodriguez-Escriba M, Camacho N, Reina O, Saint-Leger A, et al. Inosine modifications in human tRNAs are incorporated at the precursor tRNA level. Nucleic acids research. 2015;43(10):5145-57. Epub 2015/04/29. 4. Zhou W, Karcher D, Bock R. Identification of enzymes for adenosine-to-inosine editing and discovery of cytidine-to-uridine editing in nucleus-encoded transfer RNAs of Arabidopsis. Plant physiology. 2014;166(4):1985-97. Epub 2014/10/16. 5. Tsutsumi S, Sugiura R, Ma Y, Tokuoka H, Ohta K, Ohte R, et al. Wobble inosine tRNA modification is essential to cell cycle progression in G(1)/S and G(2)/M transitions in fission yeast. J Biol Chem. 2007;282(46):33459-65. Epub 2007/09/19. 6. Crick FH. Codon--anticodon pairing: the wobble hypothesis. Journal of molecular biology. 1966;19(2):548-55. Epub 1966/08/01. 7. Torres AG, Pineyro D, Filonava L, Stracker TH, Batlle E, Ribas de Pouplana L. A-to-I editing on tRNAs: biochemical, biological and evolutionary implications. FEBS Lett. 2014;588(23):4279-86. Epub 2014/09/30. 8. Novoa EM, Pavon-Eternod M, Pan T, Ribas de Pouplana L. A role for tRNA modifications in genome structure and codon usage. Cell. 2012;149(1):202-13. Epub 2012/04/03. 9. Schaub M, Keller W. RNA editing by adenosine deaminases generates RNA and protein diversity. Biochimie. 2002;84(8):791-803. Epub 2002/11/30. 10. Rafels-Ybern A, Attolini CS, Ribas de Pouplana L. Distribution of ADAT-Dependent Codons in the Human Transcriptome. International journal of molecular sciences. 2015;16(8):17303- 14. Epub 2015/08/01. 11. Rafels-Ybern A, Torres AG, Grau-Bove X, Ruiz-Trillo I, de Pouplana LR. Codon adaptation to tRNAs with Inosine modification at position 34 is widespread among Eukaryotes and present in two Bacterial phyla. RNA biology. 2017:0. Epub 2017/09/08. 12. Wulff TF, Arguello RJ, Molina Jordan M, Roura Frigole H, Hauquier G, Filonava L, et al. Detection of a Subset of Posttranscriptional Transfer RNA Modifications in Vivo with a Restriction Fragment Length Polymorphism-Based Method. Biochemistry. 2017;56(31):4029-38. Epub 2017/07/14. 13. Sinkeldam RW, McCoy LS, Shin D, Tor Y. Enzymatic interconversion of isomorphic fluorescent nucleosides: adenosine deaminase transforms an adenosine analogue into an inosine analogue. Angew Chem Int Ed Engl. 2013;52(52):14026-30. Epub 2013/11/30. 14. McCoy LS, Shin D, Tor Y. Isomorphic emissive GTP surrogate facilitates initiation and elongation of in vitro transcription reactions. Journal of the American Chemical Society. 2014;136(43):15176-84. Epub 2014/09/26. 15. Rovira AR, Fin A, Tor Y. Chemical Mutagenesis of an Emissive RNA Alphabet. J Am Chem Soc. 2015;137(46):14602-5. Epub 2015/11/03. 16. Juhling F, Morl M, Hartmann RK, Sprinzl M, Stadler PF, Putz J. tRNAdb 2009: compilation of tRNA sequences and tRNA genes. Nucleic acids research. 2009;37(Database issue):D159-62. Epub 2008/10/30. 17. Alazami AM, Hijazi H, Al-Dosari MS, Shaheen R, Hashem A, Aldahmesh MA, et al. Mutation in ADAT3, encoding adenosine deaminase acting on transfer RNA, causes intellectual disability and strabismus. Journal of medical genetics. 2013;50(7):425-30. Epub 2013/04/27. 18. El-Hattab AW, Saleh MA, Hashem A, Al-Owain M, Asmari AA, Rabei H, et al. ADAT3- related intellectual disability: Further delineation of the phenotype. American journal of medical genetics Part A. 2016;170A(5):1142-7. Epub 2016/02/05.

Diabetes mellitus (DM) is a metabolic disorder of multiple etiology characterized by chronic hyperglycemia resulting from deficiency of insulin production and/or action. This state of hyperglycemia may cause a variety of cardiovascular, renal, neurological and eye complications. Adenosine deaminase (ADA) is an important enzyme responsible for regulation the levels of adenosine (ado) an important component of the system purinergic nucleoside. Changes in ADA activity has been demonstrated in several diseases, including DM. The Rutin (RT) is an abundant polyphenolic flavonoid found in food that exhibits multiple pharmacological activities including antibacterial, antitumoural, vasodilator and hepatoprotective activities. The objective of this study was to investigate the effect of RT on the activity of ADA in serum, tissues and biochemical parameters in models of diabetes induced by streptozotocin (STZ). Diabetes was induced in rats by an intraperitoneal injection of streptozotocin (STZ). RT (100 mg/kg/day) and glibenclamide (10mg/kg/day) were administered for 30 days, except for control groups (non diabetic and diabetic). Six groups of rats were used in the study and grouped based on fasting blood glucose levels after diabetes induction. The results showed an increase in ADA activity in serum and liver of diabetic rats, like transaminases (AST, ALT), -glutamyltransferase (-GT) and glucose. The RT at a concentration of 100 mg/kg was able to reduce the ADA activity in serum and liver tissue when compared with the diabetic control. The protective effect of RT was also observed increases the activity of enzymes ALT and -GT. Significant reductions were also observed in total cholesterol and LDL-cholesterol as well as in blood glucose levels in the diabetic group treated with RT. The results suggest that RT can improve hyperglycemia and hyperlipidemia, and restoring damaged liver function, as well as prevents the increase in ADA activity in serum and liver tissue on diabetic rats treated with this flavonoid.
O Diabetes mellitus (DM) é uma disfunção metabólica de múltipla etiologia caracterizado por hiperglicemia crônica resultante da deficiência da produção e/ou ação da insulina. Esse estado de hiperglicemia pode provocar uma série de complicações cardiovasculares, renais, neurológicas e oculares. A Adenosina deaminase (ADA) é uma importante enzima responsável por regular os níveis de adenosina (ado), um importante nucleosídeo componente do sistema purinérgico. Alterações na atividade da ADA têm sido demonstradas em várias doenças, incluindo o DM. A rutina (RT) é um flavonoide polifenólico abundante nos alimentos que exibe múltiplas atividades farmacológicas como atividade antibacteriana, antitumoral, vasodilatadora e hepatoprotetora. O objetivo deste estudo foi verificar o efeito da RT sobre a atividade da ADA sérica e tecidual e parâmetros bioquímicos em modelos de diabetes induzidos por estreptozotocina (STZ). O diabetes foi induzido através de injeção única intraperitoneal (i.p.) de 55 mg/kg de STZ. A RT (100 mg / kg / dia) e a glibenclamida (10mg/kg/dia) foram administradas durante 30 dias, com exceção dos grupos controles (não diabéticos e diabéticos). Seis grupos de ratos foram utilizados no estudo e agrupados com base nos níveis de glicose em jejum após a indução de diabetes. Os resultados demonstraram um aumento na atividade da ADA no soro e no fígado de ratos diabéticos, assim como das transaminases (AST, ALT), -glutamiltransferase (-GT) e glicose. A RT na concentração de 100 mg/kg foi capaz de reduzir a atividade sérica e em tecido hepático da ADA quando comparado com o controle. O efeito protetor da RT também foi observado sobe a atividade das enzimas ALT e -GT. Reduções significativas foram observadas no colesterol total e LDL-colesterol, bem como, na concentração sérica de glicose no grupo diabético tratado com RT. Os resultados sugerem que a RT pode melhorar a hiperglicemia e dislipidemia, restabelecer danos à função hepática, bem como é capaz de prevenir o aumento da atividade da ADA no soro e no fígado de ratos diabéticos tratados com este flavonoide.

Ischaemic heart disease is a major contributor to premature death and heart failure in the Westernised world. Ischaemic injury within the heart may be beneficially modulated by the nucleoside adenosine. Derived from catabolism of ATP, adenosine was initially known as a potent bradycardic and hypotensive agent. However, more recently the protective function of adenosine has been investigated. The protective effects of adenosine are mediated via activation of adenosine receptors: A1, A2A, A2B, and A3 receptors. Activation of these potentially protective (or retaliatory) adenosine receptors hinges upon accumulation of adenosine during ischaemia-reperfusion. This Thesis examines the role and mechanisms of adenosine mediated cardioprotection in young and aged hearts, exploring endogenous and exogenous adenosine receptor activation, genetic manipulation of A1 receptors and adenosine deaminase and pharmacological manipulation of adenosine metabolism. The effects of age on ischaemic responses and adenosine handling and protection are also assessed. The core approach to assess each of the above issues involved the Langendorff isolated mouse heart preparation. Experiments within Chapter 3 focuses on the contractile effects of adenosine receptors in normoxic hearts. This study indicates A2A receptors have no direct effect on contractility, while adenosine exerts positive inotropy independently of coronary flow and perfusion pressure (i.e. Independent of the Gregg phenomenon). In addition, investigations in genetically modified hearts hint at positive inotropy in response to A1 receptors. Since the latter is only evidenced in modified lines, it is possible A1-mediated inotropy may be abnormal or supraphysiological. In Chapter 4 the impact of genetic 'deletion' of A1ARs and/or adenosine deaminase (ADA) on intrinsic tolerance to ischaemia were studied. Data demonstrate that genetic deletion of A1 receptors significantly limits the ability of the mouse myocardium to withstand injury during ischaemic insult. Thus, providing strong support for a role of A1ARs in determining intrinsic tolerance to ischaemia-reperfusion. ADA KO mice confirm protection afforded by endogenous adenosine and the notion of adenosine metabolism modification as a protective strategy. Interestingly, effects of A1AR KO differ from A1AR overexpression or A1AR agonism in that the latter decrease contractile diastolic dysfunction while A1AR KO selectively increase systolic dysfunction and increase oncosis without altering diastolic injury. This challenges current dogma regarding the action of A1 adenosine receptors on ischaemic injury. In Chapter 5 the effects of adenosine metabolism inhibition (via adenosine deaminase (ADA) and adenosine kinase (AK) inhibitors) were studied. Inhibition of adenosine deaminase with the drug EHNA, and adenosine phosphorylation with iodotubercidin significantly protected mouse hearts from ischaemia-reperfusion, reducing contractile dysfunction and cardiac enzyme efflux. However, inhibitors failed to improve the outcome of the aged myocardium. 8-SPT and 5-HD reduced the protective effects of EHNA and iodotubercidin demonstrating thus; cardioprotection via ADA and AK appears to rely on adenosine receptor activation and involves a mitoK ATP dependent mechanism. Since aging is of considerable importance with regard to outcomes of ischaemic heart disease, experiments in Chapter 6 focused on effects of aging (and gender) on cardiovascular function and injury during ischaemia-reperfusion. In assessing post ischaemic outcomes in hearts from young adult (2-4 months), mature adult (8 months), middle aged (12 months), aged (18 months) and senescent (24-28 months) C57/BL/6J mice, data reveal a substantial age-related decline in ischaemic tolerance (which appears selective for myocardial vs. vascular injury). The decline in ischaemic tolerance is expressed primarily within the initial 12 months in both males and females with relatively little further decline with continued aging. There is evidence of a modest improvement in tolerance in senescence vs. aged hearts possibly reflecting selection of a protected phenotype in senescent populations. In addition, mature and middle-aged female hearts showed improved tolerance to ischaemia-reperfusion compared to males, supporting a role for hormonal changes. Effects of aging and purine metabolism were studied in Chapter 7. Data suggest impaired tolerance to ischaemia-reperfusion in older hearts may stem in part from shifts in myocardial purine catabolism. Data reveal reduced accumulation of salvageable and cardioprotective adenosine and enhanced accumulation of poorly salvaged (and potentially injurious) hypoxanthine and xanthine. These changes may potentially predispose the aged myocardium to ischaemic injury and radical generation via the xanthine oxidase reaction. The final data Chapter of this Thesis describes preliminary data regarding aging, signalling and adenosine mediated protection. It was found that protein kinase C (PKC) and A1 receptors mediate protection in young hearts and also that A1 receptors appear to mediate protection via a PKC LindependentLi signalling cascade. In addition, experiments in aged hearts (attempting to elucidate mechanisms behind impaired adenosinergic protection with age) suggest a PKC-independent A1-mediated protection path may be preserved with aging, since A1 receptors continue to offer some protection while PKC activation does not. It is possible the failure of exogenous adenosine to offer protection in aged hearts may result from a lesion at or downstream of PKC.

Ischaemic heart disease is a major contributor to premature death and heart failure in the Westernised world. Ischaemic injury within the heart may be beneficially modulated by the nucleoside adenosine. Derived from catabolism of ATP, adenosine was initially known as a potent bradycardic and hypotensive agent. However, more recently the protective function of adenosine has been investigated. The protective effects of adenosine are mediated via activation of adenosine receptors: A1, A2A, A2B, and A3 receptors. Activation of these potentially protective (or retaliatory) adenosine receptors hinges upon accumulation of adenosine during ischaemia-reperfusion. This Thesis examines the role and mechanisms of adenosine mediated cardioprotection in young and aged hearts, exploring endogenous and exogenous adenosine receptor activation, genetic manipulation of A1 receptors and adenosine deaminase and pharmacological manipulation of adenosine metabolism. The effects of age on ischaemic responses and adenosine handling and protection are also assessed. The core approach to assess each of the above issues involved the Langendorff isolated mouse heart preparation. Experiments within Chapter 3 focuses on the contractile effects of adenosine receptors in normoxic hearts. This study indicates A2A receptors have no direct effect on contractility, while adenosine exerts positive inotropy independently of coronary flow and perfusion pressure (i.e. Independent of the Gregg phenomenon). In addition, investigations in genetically modified hearts hint at positive inotropy in response to A1 receptors. Since the latter is only evidenced in modified lines, it is possible A1-mediated inotropy may be abnormal or supraphysiological. In Chapter 4 the impact of genetic 'deletion' of A1ARs and/or adenosine deaminase (ADA) on intrinsic tolerance to ischaemia were studied. Data demonstrate that genetic deletion of A1 receptors significantly limits the ability of the mouse myocardium to withstand injury during ischaemic insult. Thus, providing strong support for a role of A1ARs in determining intrinsic tolerance to ischaemia-reperfusion. ADA KO mice confirm protection afforded by endogenous adenosine and the notion of adenosine metabolism modification as a protective strategy. Interestingly, effects of A1AR KO differ from A1AR overexpression or A1AR agonism in that the latter decrease contractile diastolic dysfunction while A1AR KO selectively increase systolic dysfunction and increase oncosis without altering diastolic injury. This challenges current dogma regarding the action of A1 adenosine receptors on ischaemic injury. In Chapter 5 the effects of adenosine metabolism inhibition (via adenosine deaminase (ADA) and adenosine kinase (AK) inhibitors) were studied. Inhibition of adenosine deaminase with the drug EHNA, and adenosine phosphorylation with iodotubercidin significantly protected mouse hearts from ischaemia-reperfusion, reducing contractile dysfunction and cardiac enzyme efflux. However, inhibitors failed to improve the outcome of the aged myocardium. 8-SPT and 5-HD reduced the protective effects of EHNA and iodotubercidin demonstrating thus; cardioprotection via ADA and AK appears to rely on adenosine receptor activation and involves a mitoK ATP dependent mechanism. Since aging is of considerable importance with regard to outcomes of ischaemic heart disease, experiments in Chapter 6 focused on effects of aging (and gender) on cardiovascular function and injury during ischaemia-reperfusion. In assessing post ischaemic outcomes in hearts from young adult (2-4 months), mature adult (8 months), middle aged (12 months), aged (18 months) and senescent (24-28 months) C57/BL/6J mice, data reveal a substantial age-related decline in ischaemic tolerance (which appears selective for myocardial vs. vascular injury). The decline in ischaemic tolerance is expressed primarily within the initial 12 months in both males and females with relatively little further decline with continued aging. There is evidence of a modest improvement in tolerance in senescence vs. aged hearts possibly reflecting selection of a protected phenotype in senescent populations. In addition, mature and middle-aged female hearts showed improved tolerance to ischaemia-reperfusion compared to males, supporting a role for hormonal changes. Effects of aging and purine metabolism were studied in Chapter 7. Data suggest impaired tolerance to ischaemia-reperfusion in older hearts may stem in part from shifts in myocardial purine catabolism. Data reveal reduced accumulation of salvageable and cardioprotective adenosine and enhanced accumulation of poorly salvaged (and potentially injurious) hypoxanthine and xanthine. These changes may potentially predispose the aged myocardium to ischaemic injury and radical generation via the xanthine oxidase reaction. The final data Chapter of this Thesis describes preliminary data regarding aging, signalling and adenosine mediated protection. It was found that protein kinase C (PKC) and A1 receptors mediate protection in young hearts and also that A1 receptors appear to mediate protection via a PKC LindependentLi signalling cascade. In addition, experiments in aged hearts (attempting to elucidate mechanisms behind impaired adenosinergic protection with age) suggest a PKC-independent A1-mediated protection path may be preserved with aging, since A1 receptors continue to offer some protection while PKC activation does not. It is possible the failure of exogenous adenosine to offer protection in aged hearts may result from a lesion at or downstream of PKC.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Medical Science
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
IntroduÃÃo: A leishmaniose visceral (LV) à uma doenÃa causada por protozoÃrios do gÃnero Leishmania e transmitida por insetos flebotomÃneos. O Brasil à uma das mais importantes Ãreas endÃmicas para a doenÃa, sendo necessÃrio o acompanhamento da ocorrÃncia dos casos atravÃs de uma vigilÃncia epidemiolÃgica ativa. A adenosina desaminase (ADA) à uma enzima que catalisa a desaminaÃÃo da adenosina produzindo inosina e amÃnia. Em humanos, està presente como duas isoenzimas e trÃs isoformas (ADA1, ADA1-CD26 e ADA2), sendo fundamental para o funcionamento do sistema imunolÃgico, uma vez que a deficiÃncia genÃtica da ADA1 provoca uma imunodeficiÃncia severa e combinada (SCID), bem como o vÃrus HIV à capaz de promover uma diminuiÃÃo na contagem dos linfÃcitos T via interaÃÃo com a ADA1-CD26. Objetivos: Descrever o perfil epidemiolÃgico da LV no Brasil (de 2001 a 2011) e no Cearà (de 2007 a 2011), bem como a atividade de ADA em pacientes acometidos pela LV. Metodologia: Realizou-se um estudo observacional descritivo da LV no Brasil e no estado do Cearà utilizando os dados secundÃrios disponibilizados pelo SINAN/MS, sendo categorizadas as Ãreas de transmissÃo; faixa etÃria, sexo e escolaridade dos casos; incidÃncia, prevalÃncia e evoluÃÃo da doenÃa; co-infecÃÃo HIV-LV e casos em gestantes. A ADA e suas isoenzimas foram determinadas em plasma de pacientes acometidos por LV utilizando o mÃtodo de Giusti, EHNA e por eletroforese. Os valores de cutoff para a ADA foram determinados utilizando a curva ROC. Resultados: A LV à endÃmica no Brasil, presente em 26 dos 27 estados, com uma mÃdia anual de ~3.600 casos, incidÃncia de ~1,79 casos/100.000hab e prevalÃncia de ~1,96 casos/100.000hab. No CearÃ, està presente em ~88% dos municÃpios, com mÃdia anual de ~600 casos, incidÃncia de 6,1casos/100.000hab e prevalÃncia de 7,1casos/100.000hab. A ADA està significativamente aumentada na LV, com uma atividade mÃdia de 106,8Â4,5U/L (vs controle 21,1Â0,6U/L). Este aumento ocorre com ambas isoenzimas, contudo a ADA2 à a principal isoenzima presente em pacientes acometidos por LV, com um valor de cutoff de 47,6 U/L para ADA total e 29,6U/L para a ADA2, utilizando adenosina. ConclusÃo: A LV à uma doenÃa endÃmica presente em todos os estados brasileiros, a exceÃÃo do Acre. Os estados do CearÃ, MaranhÃo e Minas Gerais apresentaram a maior quantidade de casos e o estado de Tocantins a maior incidÃncia e prevalÃncia. O Cearà à uma Ãrea endÃmica para a LV e a cidade de Fortaleza à o municÃpio que registrou a maior quantidade de casos no paÃs. A ADA pode ser utilizada como um marcador da resposta inflamatÃria na LV, e a determinaÃÃo da isoenzima ADA2 pode ser utilizada para avaliar a ativaÃÃo ou participaÃÃo de monÃcitos e macrÃfagos no processo infeccioso.
Introduction: Visceral leishmaniasis (VL) is a disease caused by protozoa of the genus Leishmania and transmitted by sandflies. Brazil is one of the most important endemic areas for the disease, being necessary monitoring of the occurrence of the disease through active epidemiological surveillance. Adenosine deaminase (ADA) is an enzyme that catalyzes the deamination of adenosine to produce inosine and ammonia. In humans, it is present as two isoenzymes and three isoforms (ADA1, ADA2 and ADA1-CD26) and is pivotal to immune system function, since ADA1âs genetic deficiency causes a severe combined immunodeficiency (SCID), as well as HIV is able to promote a decrease in the count of T lymphocytes via interaction with ADA1-CD26. Objectives: To describe the epidemiology of VL in Brazil (2001-2011) and Cearà (2007-2011); and the ADA activity in patients suffering from VL. Methods: We conducted an observational descriptive study of VL in Brazil and in the state of Cearà using secondary data provided by SINAN/MS, being categorized the transmission areas, age, sex and education of cases, incidence, prevalence and evolution of disease, co-infection HIV-VL and cases among pregnant women. The ADA and its isoenzymes were determined in plasma of patients suffering from LV using the method of Giusti, EHNA and electrophoresis. The cutoff values for the ADA were determined using the ROC curve. Results: VL is endemic in Brazil and is present in 26 of 27 states, with an annual average of ~ 3,600 cases, incidence of ~1.79 cases/100.000 inhabitants and prevalence of ~1.96 cases/100.000 inhabitants. In CearÃ, it is present in ~88 % of the municipalities, with an annual average of ~ 600 cases, incidence of 6.1 cases/100.000 inhabitants and prevalence of 7.1 cases/100.000 inhabitants. The ADA activity is significantly increased in LV, with an average activity of 106.8  4.5 U / L (vs. control 21.1  0.6 U / L). This increase occurs with both isoenzymes, but the ADA2 is the major isoenzyme present in patients suffering from LV, with a cutoff value of 47.6 U / L for total ADA activity and 29.6 U/L for ADA2 activity, using adenosine. Conclusion: LV is an endemic disease present in all Brazilian states, with the exception of Acre. The states of CearÃ, MaranhÃo and Minas Gerais had the highest number of cases and the state of Tocantins a higher incidence and prevalence. Cearà is an endemic area for VL and the city of Fortaleza is the municipality that the highest number of cases in the country. ADA can be used as a marker of the inflammatory response in VL, and the determination of isoenzyme ADA2 can be used to evaluate the activation or participation of monocytes and macrophages in the infectious process.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.
Objectives: Diagnosis of tuberculous meningitis (TM) is a challenge in countries with a high burden of the disease and constrained resources and clinical prediction rules (CPRs) could be of assistance. We aimed at developing a CPR for diagnosis of TM in a Latin American setting with high tuberculosis incidence and a concentrated HIV epidemic. Methods: We enrolled adult patients with clinical suspicion of TM attending two hospitals in Lima, Peru. We obtained information on potential anamnestic, clinical and laboratory predictive findings that are easy to collect and promptly available. We independently diagnosed TM according to a composite reference standard that included a series of microbiological tests. We performed bivariate analysis and constructed a logistic regression model to select the predictive findings associated with TM. With the selected predictors included in the model, we developed a score-based CPR. We assessed its internal validity and diagnostic performance. Results: Of 155 analysed patients, 59 (38%) had TM. The CPR we derived includes three predictors: cough for 14 days or more, 10–500 cells in CSF and adenosine deaminase ≥ 6 U/l in CSF. It classifies patients into high-, moderate- or low-score groups and has an overall area under the ROC curve of 0.87. 59% of patients were assigned to either the high- or the low-score group, permitting prompt decision-making. In patients in the high-score group, it attains a positive likelihood ratio for TM of 10.6 and in patients with low scores, a negative likelihood ratio of 0.10. Bootstrap analysis indicated high internal validity. Conclusion: This CPR could support decision-making in patients with clinical suspicion of TM. External validation and further assessment of its clinical impact are necessary before application in other settings.
Revisión por pares

Trichomonas vaginalis é o protozoário flagelado que parasita o trato urogenital humano causando a tricomonose, doença sexualmente transmissível (DST) de origem não viral mais comum no mundo. Durante a infecção a aquisição de nutrientes, como nucleotídeos púricos, pirimidínicos e ferro é essencial à sobrevivência do parasito. T. vaginalis não sintetiza de novo purinas e pirimidinas, dependendo de vias de salvação para aquisição destas moléculas. O ferro desempenha um papel crucial na patogenicidade da tricomonose, influenciando a expressão de múltiplos genes envolvidos na virulência. Nucleotídeos extracelulares, especialmente o ATP, são liberados em situações de estresse, anoxia ou injúria, atuando como sinalizadores pró-inflamatórios ao sistema imune. As enzimas NTPDase e ecto-5'-nucleotidase degradam ATP à adenosina, esta com ação anti-inflamatória. A enzima adenosina deaminase (ADA) degrada adenosina à inosina. A presença desta cadeia enzimática em T. vaginalis sugere a modulação das concentrações nucleotídeos/nucleosídeos durante a inflamação. A atividade da ADA foi caracterizada em T. vaginalis, porém há poucos relatos sobre a participação desta enzima na sobrevivência do parasito, bem como, a localização celular e o efeito de nutrientes essenciais na atividade enzimática e na expressão gênica. O estudo da localização da ADA em T. vaginalis foi realizado, indicando a presença da enzima na membrana celular e no citoplasma do trofozoíto. Avaliando-se o perfil da ADA de diferentes isolados de T. vaginalis em uma condição de limitação de soro bovino, o qual representa a fonte de adenosina aos trofozoítos, não se observou diferenças significativas na deaminação da adenosina à inosina. Na avaliação do efeito de diferentes fontes de ferro ou a privação deste cátion na atividade e na expressão gênica da ADA foi possível verificar uma diminuição da atividade e um aumento na expressão gênica após a privação do ferro, reforçando a hipótese que este elemento pode modular a atividade das enzimas envolvidas na sinalização purinérgica. Os resultados obtidos nesta dissertação permitem a avaliação de importantes aspectos da ADA, contribuindo para o melhor entendimento do sistema purinérgico em T. vaginalis e seu papel no estabelecimento e manutenção da infecção e consequente sobrevivência do parasito.
Trichomonas vaginalis is a flagellate protozoan that parasitizes the urogenital human tract causing trichomonosis, the non-viral sexually transmitted disease (STD) most common in the world. During infection the acquisition of nutrients such as purine and pyrimidine nucleotides, and iron is essential to the parasite survival. T. vaginalis lacks de novo purines and pyrimidines synthesis depending on the salvation pathway for the acquisition of these molecules. Iron plays a crucial role in trichomonosis pathogenesis, influencing the expression of multiple genes involved in virulence. Extracellular nucleotides, especially ATP, are released during stress, injury or anoxia, acting as a pro-inflammatory signaling to the immune system. The enzymes NTPDase and ecto-5'-nucleotidase degrade ATP to adenosine with anti-inflammatory action. The adenosine deaminase (ADA) enzyme degrades adenosine to inosine. The presence of this enzymatic chain in T. vaginalis suggests the modulation of nucleotides/nucleosides concentrations during inflammation. The ADA activity was characterized in T. vaginalis, but there are few reports on the participation of this enzyme in the parasite survival, as well as the cellular localization and the effect of essential nutrients on enzyme activity and gene expression. The study of ADA localization in T. vaginalis was performed, indicating the presence of the enzyme on trophozoite cell membrane and cytoplasm. Evaluating the ADA profile in different T. vaginalis isolates in bovine serum limitation condition, which is the source of adenosine for the trophozoites, no significant differences were observed in the deamination of adenosine to inosine. Regarding the effect of different iron sources or iron deprivation in activity and gene expression of ADA, it was observed a decrease in activity and an increase in gene expression after iron deprivation, reinforcing the hypothesis that this element can modulate the activity of enzymes involved in the purinergic signaling. The results obtained in this study allow the assessment of important aspects of ADA, contributing to a better understanding of the purinergic system in T. vaginalis and its role in the establishment and maintenance of infection and consequent survival of the parasite.

This study was designed to: 1. Examine the diagnostic value of ADA levels in ascitic fluid, 2. Establish the sensitivity and specificity of this test in the diagnosis of tuberculous peritonitis, in a large number of patients, 3. Establish levels of adenosine deaminase activity which give the best discriminatory information in patients with ascites. 4. Determine what conditions may give rise to false positive or false negative results. 5. Finally, the study was designed to assess the relative diagnostic accuracy of previously used biochemical and haematological data, such as ascites total protein and white cell count. The diagnostic value of these tests alone, and combined with ADA activity in a descriminant analysis, was compared with the diagnostic accuracy of adenosine deaminase activity alone.

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UNIEDU
FUMDES
T. evansi causes a highly pathogenic disease in horses popularly known as "Surra" or "Mal das Cadeiras". The Pantanal (Brazil) outbreaks are recorded due to the large population of horses. To date there are no effective treatment methods causing major damage to livestock. Trypanosomes present themselves vulnerable in relation to the metabolism of purines as these organisms do not have the pathway “De novo” of meeting their requirements through the rescue of preformed bases and demonstrate complete dependence of purines of their hosts. Among the components of this system point out that adenosine has its concentration controlled by the enzyme adenosine deaminase (ADA). The objectives of this study were to amplify, clone and sequence the ADA gene from T. evansi DNA samples and express the recombinant protein ADA. The coding region of the ADA gene was amplified from genomic DNA of T. evansi and yielded a sequence of 1857 bp showed high degree of similarity (95%) ADA T. brucei. This region was cloned into the pGEM-T vector Easy®. After digestion of construct pGEM: ADA fragments were cloned into expression vector pET30. The expression analysis by SDS-PAGE demonstrated that the temperature of 18ºC for 24 hours and 0,05 mM IPTG induction was the most effective indicating molecular mass of approximately 68 kDa. The Western blot analysis detected the ADA enzyme in the protein extract of T. evansi only in the insoluble fraction. The protein was solubilized and purified by affinity chromatography. Through these results the presence of ADA in T. evansi was confirmed. tests will be performed to detect the enzymatic activity of ADA. Their study can contribute to the development of new chemotherapeutic agents and the development of specific inhibitors for the ADA
T. evansi causa uma doença altamente patogênica em equídeos popularmente conhecida como “Surra” ou “Mal das Cadeiras”. No Pantanal (Brasil) surtos são registrados devido à grande população de equinos. Até o presente momento não existem métodos de tratamento eficazes gerando grandes prejuízos à pecuária. Os tripanossomas apresentam-se vulneráveis em relação ao metabolismo das purinas pois estes organismos não contam com a via De novo satisfazendo suas exigências por meio do salvamento das bases pré-formadas e demonstram completa dependência das purinas dos seus hospedeiros. Entre os componentes desse sistema destacamos a adenosina que tem sua concentração controlada pela enzima adenosina deaminase (ADA). Os objetivos deste estudo foram amplificar, clonar e sequenciar o gene ADA a partir de amostras do DNA de T. evansi e expressar a proteína recombinante ADA. A região codificadora do gene da enzima ADA foi amplificada a partir do DNA genômico de T. evansi e originou uma sequência de 1857 bp que apresentou alto grau de similaridade (95%) com a enzima ADA de T. brucei. Essa região foi clonada no vetor pGEM-T Easy®. Após a digestão da construção pGEM:ADA, os fragmentos foram clonados em vetor de expressão pET30. A análise da expressão através do SDS-PAGE demonstrou que a temperatura de 18ºC por 24 horas e indução com IPTG 0.05 mM foi a mais eficiente indicando massa molecular de aproximadamente 68 kDa. A análise Western-Blot detectou a enzima ADA no extrato proteico de T. evansi apenas na fração insolúvel. A proteína foi solubilizada e purificada por meio da cromatografia de afinidade. SDS-PAGE e o Western-blot confirmaram a eficiência destes protocolos. Através desses resultados a presença da enzima ADA em T. evansi foi confirmada. Seu estudo pode contribuir para o desenvolvimento de novos agentes quimioterápicos e o desenvolvimento de agentes inibidores específicos para ADA

An inherited disorder, ADA deficiency, is a form of severe combined immunodeficiency, which is ultimately caused by an absence of adenosine deaminase (ADA), a key enzyme of the purine salvage pathway. The absence of ADA-activity in sufferers eventually results in a dysfunctional immune system due to the build-up of toxic metabolites. To date, this has been treated with mixed success, using PEG-ADA, made from purified bovine ADA coupled to polyethylene glycol. It is likely however, that an enzyme replacement therapy protocol based on recombinant human ADA would be a more effective treatment for this disease. Therefore, as a preliminary step to produce biologically active human ADA in transgenic tobacco plants and tobacco BY-2 cell suspensions a human ADA cDNA has been inserted into a plant expression vector under the control of the CaMV 35S promoter and terminator. In an attempt to maximise the yield various recombined gene constructs containing apoplast targeting sequences were tested along with different translational regulatory sequences such as TMV omega and RUBISCO untranslated regions. Tobacco plants and BY-2 cells transformed with cytosolic constructs showed levels of recombinant ADA of up to 80 ng mg-1 TSP. By comparison, transgenic calli expressing constructs containing apoplast-directing signals showed higher levels of recombinant ADA expression of up to 115 ng mg-1 TSP. The most significant ADA activities were measured in transgenic BY-2 cell suspensions, however. Where, incorporation of a signal for arabinogalactan addition at the C-terminus of the recombinant ADA gene, targeted for secretion, produced a maximum yield of approximately 13 mg L-1. Representing a 336-fold increase over ADA activities recorded in a BY-2 suspension transformed with a cytosolic counterpart.

Thesis (Ph. D.)--West Virginia University, 2001.
Title from document title page. Document formatted into pages; contains xii, 195 p. : ill. Vita. Includes abstract. Includes bibliographical references.

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Neonatal hypoxic-ischemic injury (HI) is the direct complication to severe choking and may cause brain damage. HI may be found in different stages and clinical manifestations contributing to neonatal morbidity and mortality. The neuropathology of neonatal HI insult is multi-factorial and complex. Hypoxic-ischemic brain damage begins during the insult and extends during the recovery period after reperfusion, thus, it is an evolutionary process. Adenosine deaminase (ADA) is an aminohidrolase actively involved in the metabolism of purines catalyzing irreversibly adenosine and 2'desoxiadenosine into inosine and 2'desoxinosine, respectively. The objectives of this study were to evaluate the activity of ADA in the cortex of rats subjected to neonatal HI at different post-insult time points. Effects of thiobarbituric acid reactive species (TBARS) levels were also assessed in cortex. The histological analysis was evaluated using hematoxylin eosin (HE) and glial fibrillary acidic protein (GFAP) in the cortex of these animals. The ADA activity was significantly increased 8 days after the insult in the left hemisphere in the cortex. In this period, TBARS levels were significantly increased in the cortex of these animals. HE revealed the presence of ischemic area in the cerebral cortex 8 days after HI. A moderate lymphocytic infiltration was also evidenced in the cortex during this period. A proliferation and an increase in the expression of GFAP in the periphery of the ischemic area was observed, resulting in astrocytosis in the cortex of these animals. In conclusion, an activation of the immune system was observed due to the inflammatory process caused by the HI insult that may be correlated with astrocytosis and lymphocytic infiltration observed in the cerebral cortex of animals that suffered insult 8 days after neonatal HI.
A lesão hipóxico-isquêmica (HI) neonatal é a complicação imediata à asfixia grave e pode causar dano cerebral. A HI pode apresentar-se em diferentes estágios e manifestações clínicas contribuindo assim intensamente na morbidade e mortalidade neonatal. A neuropatologia do insulto HI neonatal é multi-fatorial e complexa. O dano cerebral hipóxicoisquêmico inicia durante o insulto e estende-se no período de recuperação após a reperfusão, portanto é um processo evolutivo. A adenosina deaminase (ADA) é uma aminohidrolase que participa ativamente do metabolismo das purinas catalisando irreversivelmente a adenosina e 2 desoxiadenosina em inosina e 2 desoxinosina, respectivamente. Os objetivos deste estudo foram avaliar em ratos submetidos à HI neonatal a atividade da ADA no córtex destes animais em diferentes tempos pós-insulto. Também foram avaliados em córtex os efeitos dos níveis de espécies reativas ao ácido tiobarbitúrico (TBARS). A análise histológica foi avaliada através da hematoxilina eosina (HE) e proteína glial fibrilar ácida (GFAP) no córtex destes animais. A atividade da ADA aumentou significativamente 8 dias após o insulto no hemisfério esquerdo no córtex. Neste período os níveis de TBARS mostraram-se significativamente aumentados no córtex destes animais. A HE revelou presença de área isquêmica no córtex cerebral 8 dias após a HI. Também evidenciou uma moderada infiltração linfocitária no córtex neste período. Houve proliferação e aumento na expressão da GFAP na periferia da área isquêmica, resultando em astrocitose no córtex dos animais submetidos à HI. Conclui-se que houve uma ativação do sistema imune em decorrência do processo inflamatório causado pelo insulto HI que pode estar correlacionada com a astrocitose e a infiltração linfocitária observada no córtex cerebral dos animais que sofreram o insulto 8 dias após a HI neonatal.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
O Clostridium difficile tem como principal fator de virulÃncia a toxina A (TxA), a qual provoca inflamaÃÃo e destruiÃÃo tecidual aguda em intestinos de animais experimentais e de pacientes com a doenÃa induzida por esta bactÃria. Em locais de injÃria tecidual, adenosina à produzida em altas concentraÃÃes, onde exerce uma sÃrie de efeitos antiinflamatÃrios, limitados por sua rÃpida degradaÃÃo pela enzima adenosina desaminase. O objetivo deste trabalho foi investigar o efeito da inibiÃÃo da enzima adenosina desaminase pelo EHNA (eritro-9-(2-hidrÃxi-3-nonil)-adenina) sobre a enterite induzida pela TxA do C. difficile em alÃa ileal de camundongos. Para isto, injetamos EHNA (90 μmol/kg) ou PBS i.p. 30 minutos antes da administraÃÃo de TxA (10 a 100 μg) ou PBS na alÃa ileal isolada. Os animais foram sacrificados 3 horas depois da induÃÃo da enterite e as alÃas foram retiradas para estudo. As razÃes peso/comprimento da alÃa e volume de secreÃÃo/comprimento da alÃa foram calculadas e amostras de tecido foram coletadas para histopatologia, dosagem de atividade de mieloperoxidase (MPO), dosagem de TNF-α, IL-1β e IL-10 por ELISA, imunohistoquÃmica para TNF-α, IL-1β, NOS induzÃvel e PTX3, e PCR para TNF-α, IL-1β e PTX3. A injeÃÃo de TxA (10 a 100 μg) nas alÃas ileais aumentou significativamente (p<0,05) as razÃes peso/comprimento da alÃa e volume de secreÃÃo/comprimento da alÃa com resultados consistentes a partir de 50 μg. A TxA promoveu significativa (p<0,05) destruiÃÃo tecidual, edema, infiltraÃÃo de cÃlulas inflamatÃrias, aumento das citocinas TNF-α e IL-1β, e elevaÃÃo de iNOS e PTX3. Todos esses parÃmetros foram significativamente revertidos com o uso do EHNA (p<0,05). Em adiÃÃo, a TxA nÃo alterou os nÃveis de IL-10 em relaÃÃo ao controle, mas o prÃ-tratamento com EHNA promoveu uma elevaÃÃo nos nÃveis desta citocina. Assim, concluÃmos que na enterite induzida pela TxA em camundongos o EHNA demonstrou um potente efeito antiinflamatÃrio, reduzindo consideravelmente a lesÃo tecidual, a migraÃÃo neutrofÃlica, a expressÃo e os nÃveis de citocinas prÃinflamatÃrias (TNF-α, IL-1β) e produzindo um aumento nos nÃveis de IL-10. AlÃm disso, a administraÃÃo de TxA induziu um aumento na expressÃo da proteÃna PTX3 e no nÃmero de cÃlulas imunomarcadas para iNOS no tecido ileal, ambos revertidos pelo EHNA
The main factor of virulence in Clostridium difficile is toxin A (TxA), which can induce inflammation and acute tissue injury in the bowels of animals and humans affected by this organism. The high concentration of adenosine generated upon injury produces a number of antiinflammatory effects limited by rapid degradation by adenosine deaminase. The objective of this study was to determine the effect of EHNA (erythro-9-(2-hydroxy-3-nonyl)-adenine) inhibition of adenosine deaminase upon TxA-induced ileal loop enteritis in mice. EHNA (90 μmol/kg) or PBS was injected i.p. 30 minutes prior to TxA (10-100 μg) or PBS instillation into the ligated ileal loop. The animals were euthanized 3 hours after enteritis induction and the ileal loops were retrieved for analysis. The weight/length ratio and the secretion volume/length ratio were calculated and tissue samples were submitted to histopathological study, myeloperoxidase assay (MPO), measurement of TNF-α, IL-1β and IL-10 levels with ELISA, immunohistochemical tests for TNF-α, IL-1β, inducible NOS and PTX3, and PCR assay for TNF-α, IL-1β and PTX3. The instillation of TxA (10-100 μg) into the ileal loop significantly increased (p<0.05) the weight/length ratio and the secretion volume/length ratio with consistent results above 50 μg. TxA induced a significant amount (p<0.05) of histological damage, edema and inflammatory cell infiltration and increased the production of TNF-α, IL-1β, iNOS and PTX3. All changes were significantly reverted by treatment with EHNA (p<0.05). Moreover, IL-10 levels remained unchanged in animals treated with TxA, but increased in animals receiving EHNA. In conclusion, in mice with TxA-induced enteritis EHNA produced considerable antiinflammatory effects, reducing tissue injury, neutrophil migration, the expression and levels of proinflammatory cytokines (TNF-α and IL-1β) and producing an increase in IL-10 levels. In addition, TxA instillation increased PTX3 expression and the number of cells immunolabeled for iNOS in the ileal tissue, both of which were reverted by EHNA

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Sporotrichosis is a subcutaneous fungal infection of evolution subacute or chronic, inflammatory lesions characterized by pyogranulomatous aspect, caused by the dimorphic fungus Sporothrix schenckii. Adenosine deaminase (ADA) is a key enzyme in the purine metabolism, promoting the deamination of adenosine, an important anti-inflammatory molecule. The increase in ADA activity has been demonstrated in several inflammatory conditions, however, no data in the literature associated with this fungal infection. The objective of this study was to evaluate the activity of serum ADA (S-ADA) and lymphocytes (L-ADA) of rats infected with S. schenckii. We used seventy-eight rats divided into two groups. In the first experiment, rats were infected subcutaneously and in the second experiment, infected intraperitoneally. Blood samples for hematologic evaluation and activities of S-ADA and ADA-L were performed on days 15, 30 and 40 post-infection (PI) to assess disease progression. In experiment II, was observed in an acute decrease in activity of S-ADA and L-ADA (p <0.05), suggesting a compensatory mechanism in the body's attempt to protect the host from excessive tissue damage. Chronicity of the disease the rats in the experiment I and II at 30 days PI, showed an increased activity of L-ADA (p <0.05), promoting an inflammatory response in an attempt to combat the spread of the agent. Thus, it is suggested that infection with S. schenckii alters the activities of S-ADA experimentally infected rats, demonstrating the involvement of this enzyme in the pathogenesis of sporotrichosis.
A esporotricose é uma infecção micótica subcutânea de evolução subaguda ou crônica, caracterizada por lesões inflamatórias de aspecto piogranulomatoso, causada pelo fungo dimórfico Sporothrix schenckii. A adenosina desaminase (ADA) é uma enzima chave no metabolismo das purinas, promovendo a desaminação da adenosina uma importante molécula anti-inflamatória. O aumento na atividade da ADA tem sido demonstrado em várias condições inflamatórias, porém, não existem dados na literatura associados com esta infecção micótica. O objetivo deste estudo foi avaliar a atividade da ADA no soro (S-ADA) e nos linfócitos (L-ADA) de ratos infectados por S. schenckii. Foram utilizados setenta e oito ratos distribuídos em dois grupos. No experimento I, os ratos foram infectados por via subcutânea e no experimento II, infectados por via intraperitoneal. A coleta de sangue para a avaliação hematológica e atividades da S-ADA e L-ADA foram realizadas nos dias 15, 30 e 40 pós-infecção (PI), para avaliar a evolução da doença. No experimento II, foi observada na fase aguda uma diminuição na atividade da S-ADA e L-ADA (p<0.05), sugerindo um mecanismo compensatório do organismo na tentativa de proteger o hospedeiro da lesão tecidual excessiva. Com a cronicidade da enfermidade os ratos do experimento I e II aos 30 dias PI, apresentaram um aumento na atividade da L-ADA (p<0.05), promovendo uma resposta inflamatória na tentativa de combater a proliferação do agente. Assim, sugere-se que a infecção pelo S. schenckii altera as atividades da S-ADA e L-ADA de ratos infectados experimentalmente, demonstrando o envolvimento desta enzima na patogênese da esporotricose.

Background: Chloride and adenosine deaminase measurements in cerebrospinal fluid are still sporadically requested as part of tuberculous meningitis work-up. In the literature, evidence is contradictory and opinion is divided on their utility in clinical practice. The accuracy of both for the early presumptive diagnosis of tuberculous meningitis was investigated in patients in a region with high prevalence of tuberculosis and HIV infection in order to inform a decision on whether to continue offering these tests to clinicians. Methods: A retrospective descriptive study of diagnostic accuracy was conducted at the National Health Laboratory Service, Groote Schuur Hospital, Cape Town, South Africa. Data were collected on all cerebrospinal fluid specimens submitted for tuberculosis culture between 1 January 2012 and 31 December 2014. Chloride and adenosine deaminase concentrations were compared with automated liquid culture for Mycobacterium tuberculosis as the reference standard. Findings: There were 2531 cerebrospinal fluid specimens submitted for tuberculosis culture during the study period; exclusion of duplicates yielded 2081 specimens. Chloride was requested on 711 (34·2%) specimens; 44 (6·2%) were tuberculosis culture-positive. Adenosine deaminase was requested on 152 (7·3%) specimens; 20 (13·2%) were culture-positive. Chloride sensitivity (<120 mmol/L) for the detection of tuberculous meningitis was 93·2% (95% confidence interval 81·3-98·6), with specificity 62·4% (58·6-66·1), positive predictive value 14% (10·3-18·6), negative predictive value 99·3% (97·9-99·9), positive likelihood ratio 2·48 (2·18-2·81), and negative likelihood ratio 0·109 (0·037-0·326). Adenosine deaminase sensitivity (>6 U/L) was 70% (45·7-88·1), specificity 89·4% (82·8-94·1), positive predictive value 50% (30·6-69·4), negative predictive value 95·2% (89·8-98·2), positive likelihood ratio 6·6 (3·72-11·7), and negative likelihood ratio 0·336 (0·171-0·657). Interpretation: In this patient population chloride and adenosine deaminase showed at best only modest performance as markers of tuberculous meningitis. However, very good negative predictive values could serve to identify patients highly unlikely to have the disease.

The tilapias are a group of African and Middle Eastern cichlid fish that are widely cultured in developed and developing countries. With many different species and sub-species, and extensive use of interspecies hybrids, identification of tilapia species is of importance in aquaculture and in wild populations where introductions occur. This research set out to distinguish between tilapia species and sub-species by retrieving species-specific nuclear DNA markers (SNPs) using two approaches: (i) sequencing of the coding regions of the ADA gene; and (ii) next-generation sequencing, both standard RADseq and double-digest RADseq (ddRADseq). The mitochondrial DNA (mtDNA) marker cytochrome c oxidase subunit I (COI) was used to verify tilapia species status. ADA gene sequence analysis was partially successful, generating SNP markers that distinguished some species pairs. Most species could also be discriminated using the COI sequence. Reference based analysis (RBA: using only markers found in the O. niloticus genome sequence) of standard RADseq data identified 1,613 SNPs in 1,002 shared RAD loci among seven species. De novo based analysis (DBA: based on the entire data set) identified 1,358 SNPs in 825 loci and RBA detected 938 SNPs in 571 shared RAD loci from ddRADseq among 10 species. Phylogenetic trees based on shared SNP markers indicated similar patterns to most prior phylogenies based on other characteristics. The standard RADseq detected 677 species-specific SNP markers from the entire data set (seven species), while the ddRADseq retrieved 38 (among ten species). Furthermore, 37 such SNP markers were identified from ddRADseq data from a subset of four economically important species which are often involved in hybridization in aquaculture, and larger numbers of SNP markers distinguished between species pairs in this group. In summary, these SNPs are a valuable resource in further investigating hybridization and introgression in a range of captive and wild stocks of tilapias.

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Adenosine deaminase (ADA), an enzyme coded by ADA gene (20q13.11) acts in adenosine metabolism and it is involved in the modulation of the immune response. ADA gene G22A polymorphism originates two co-dominants alleles ADA*01 and ADA*02 and influences the level of ADA enzyme in the organism. Apparently it has a fundamental role in gestational maintenance. The ADA*02 allele has been associated as protector effect against recurrent spontaneous abortion (RSA) in European Caucasian women. Aim: To investigate if ADA gene G22A polymorphism is associated with occurrence of RSA in Brazilian women. Methods: After obtaining the written consent 311 women were selected to compose two groups: G1 with previous history of RSA (n=129) and G2 without previous history of RSA (n=182). Genomic DNA was isolated from peripheral blood using commercial kits. The PCR-RFLP method was used to identify ADA gene G22A polymorphism. p>0005 was considered statistically significant. Results: The frequencies of ADA*01;*01, ADA*01;*02 and ADA*02;*02 genotypes were similar in both groups (G1 and G2) with no statistically significance differences observed (p = 0,7170; x2 = 0,6653; GL = 2). ADA*01 and ADA*02 alleles frequencies were 95,6% and 4,4% in G1 group and 94,9% and 5,1% in G2 group, respectively (p = 0,8433; OR = 1,179; CI 95%: 0,5340 2.601). Conclusion: The results suggest that ADA alleles ADA*01 and ADA*02 are not associated with RSA. It xvi is possible that the reduction of ADA levels resulting from the presence of at least one ADA*02 allele do not have a role against abortion in Brazilian women.
Polimorfismo G22A do gene ADA e abortamento espontâneo recorrente: ausência de associação Introdução: A adenosina deaminase (ADA), uma enzima codificada pelo gene ADA (20q13.11), atua no metabolismo da adenosina e modula a resposta imune. O polimorfismo G22A deste gene origina os alelos co-dominantes ADA*01 e ADA*02 e influencia o nível de expressão da enzima ADA, que possui papel fundamental na manutenção da gestação. O alelo ADA*02 tem sido associado a um efeito protetor contra o abortamento espontâneo recorrente (AER) em mulheres caucasianas européias. Objetivo: Investigar se o polimorfismo G22A do gene ADA se associa à ocorrência de AER em brasileiras. Métodos: Após obtenção do Termo de Consentimento Livre e Esclarecido (Parecer CEP FAMERP 308/2008), 311 mulheres foram selecionadas para compor dois grupos: G1 com histórico de AER (N=129) e G2 sem histórico de AER (N=182). O DNA genômico foi extraído a partir de sangue periférico com o uso kit comercial. O polimorfismo G22A do gene ADA foi identificado com o uso do método PCR-RFLP. O valor p>0,005 foi considerado significante. Resultados: As frequências dos genótipos ADA*01;*01, ADA*01;*02 e ADA*02;*02 foram semelhantes entre os grupos e não apresentaram diferenças estatisticamente significantes (p = 0,7170; χ2 = 0,6653; GL = 2). As frequências dos alelos ADA*01 e ADA*02 em G1 foram iguais a 95,6% e 4,4%; em G2, 94,9% e 5,1%, respectivamente (p=0,8433; OR=1,179; IC 95%: 0,5340-2.601). Conclusões: Os resultados sugerem que xiv os alelos ADA*01 e ADA*02 do gene ADA não estão associados ao AER. É possível que a redução nos níveis da ADA resultantes do alelo ADA*02 não apresente um efeito protetor contra o AER em brasileiras.

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Diabetes mellitus (DM) is a metabolic disorder of multiple etiology characterized by chronic hyperglycemia resulting from deficiency of production and / or insulin action. This state of hyperglycemia may cause a variety of cardiovascular, renal, neurological and eye complications. Adenosine deaminase (ADA), ecto-5 'nucleotidase (5'NT) and Acetylcholinesterase (AChE) are important enzymes responsible for regulating the levels of adenosine (ado) and acetylcholine (ACh) respectively, and changes in their activities have been demonstrated in various diseases, including Diabetes. Syzygium cumini is a plant mostly used for the treatment of DM and presents hypoglycemic, anti-inflammatory, antipyretic and antioxidants properties. The aim of this study was to verify the effect of aqueous leaf extract of Syzygium cumini (ASc) in 100 and 200μg/mL concentrations, in vitro, on enzymes 5'NT in platelets, ADA in erythrocytes and platelets and AChE in erythrocytes, as well as on parameters of oxidative stress in samples of Type 2 diabetic patients. The results showed an increase in the activity of ADA and 5'NT in platelets from diabetic (n=30) compared to the control group (n=17), as well as in the levels of thiobarbituric acid reactive species (TBARS). ASc at concentrations of 100 and 200 μg / mL was able to reverse these effects. Correlations between 5 NT activity and triglycerides levels, as well as between ADA activity and glucose levels were also found in this work. An increase in the activity of enzymes ADA and AChE in erythrocytes of patients with type 2 diabetes (n=30) compared to the control group (n=20), as well as changes in parameters of oxidative stress, such as increased levels of TBARS and decrease in superoxide dismutase (SOD) activity and levels of non-protein sulfhydryl groups (NP-SH) in these cells also were observed. Likewise, ASc reduced the ADA and AChE activities and lipid peroxidation, and reversed the effect of the evaluated oxidative parameters. Still, there were found significant positive correlations between levels of Vitamin C and protein sulfhydryl groups (P-SH), plasma glucose and levels of P-SH and NP-SH, levels of P-SH and ADA activity, besides a negative correlation between TBARS and NP-SH levels. Therefore, it is possible to suggest that the ASc was able to promote a compensatory response in the platelet function and may act in the maintenance of adenosine levels and vasodilatation and thereby, contributes to the maintenance of the vascular integrity which is important in the hyperglycemic state. It is also possible that ASc might modulate the levels of ACh, interfering with oxidative stress and / or inflammatory processes from the diabetic state. So far, these results confirm the already known antioxidants properties of Syzygium cumini, which makes this compound present significant effects on the cellular metabolism, as well as the reduction and prevention of cardiovascular disease risk in diabetics.
O Diabetes mellitus (DM) é uma disfunção metabólica de múltipla etiologia caracterizado por hiperglicemia crônica resultante da deficiência da produção e/ou ação da insulina. Esse estado de hiperglicemia pode provocar uma série de complicações cardiovasculares, renais, neurológicas e oculares. A adenosina deaminase (ADA), ecto-5 nucleotidase (5 NT) e acetilcolinesterase (AChE) são importantes enzimas responsáveis por regular os níveis de adenosina (ado) e acetilcolina (ACh), respectivamente, e alterações nas suas atividades têm sido demonstradas em várias doenças, incluindo o DM. O Syzygium cumini é uma das plantas mais utilizadas no tratamento do DM, apresenta propriedades hipoglicêmicas, antiinflamatórias, antipiréticas e antioxidantes. O objetivo deste estudo foi verificar o efeito do extrato aquoso das folhas de Syzygium cumini (ASc), nas concentrações de 100 e 200 μg/mL, in vitro, sobre as enzimas 5 NT em plaquetas, ADA em eritrócitos e plaquetas e AChE em eritrócitos, bem como sobre parâmetros de estresse oxidativo em amostras de pacientes diabéticos Tipo 2. Os resultados demonstraram um aumento na atividade das enzimas ADA e 5 NT em plaquetas de diabéticos (n=30) em relação ao grupo controle (n=17), assim como nos níveis de espécies reativas ao ácido tiobarbitúrico (TBARS). ASc, nas concentrações de 100 e 200 μg/mL foi capaz de reverter estes efeitos. Correlações entre a atividade da 5 NT e os níveis de triglicerídeos, bem como entre a atividade da ADA e os níveis de glicose também foram encontradas nesse trabalho. Um aumento na atividade das enzimas ADA e AChE em eritrócitos de pacientes com Diabetes tipo 2 (n=30) em relação ao grupo controle (n=20), além de alterações nos parâmetros de estresse oxidativo, como aumento nos níveis de TBARS e redução na atividade da enzima Superóxido Dismutase (SOD) e nos níveis de grupamentos sulfidrílicos não protéicos (NP-SH) nessas células também foram observados. Igualmente, ASc reduziu a atividade das enzimas ADA e AChE e a lipoperoxidação, e reverteu o efeito dos parâmetros oxidantes avaliados. Ainda foram encontradas correlações positivas significativas entre os níveis de Vitamina C e grupamentos sulfidrílicos protéicos (P-SH), glicose plasmática e níveis de P-SH e NP-SH, níveis de P-SH e atividade da ADA, além de correlação negativa entre os níveis de TBARS e NP-SH. Portanto, é possível sugerir que o ASc foi capaz de promover uma resposta compensatória na função plaquetária, podendo atuar na manutenção dos níveis de adenosina e na vasodilatação e, assim, contribuindo para a manutenção da integridade vascular importante no estado hiperglicêmico, tendo em vista o papel cardioprotetor exercido pela mesma. Também é possível que ASc possa modular os níveis de ACh, interferindo no estresse oxidativo e/ou nos processos inflamatórios provenientes do estado diabético. Ao mesmo tempo esses resultados corroboram com as já conhecidas propriedades antioxidantes de Syzygium cumini, o que faz com que esse composto apresente efeitos significativos no metabolismo celular, bem como na redução e prevenção do risco de doença cardiovascular em diabéticos.

Methylmercury (MeHg) is a potent neuro and nephrotoxicant in several animal species including humans, particularly during their development. The purpose of this study was to investigate the effects of aqueous seed extract of Syzygium cumini (L.) Skeels (Scc) on the acute MeHg treatment in neonatal rats. Neonatal rats (P2) received orally a single dose of MeHg (10 mg/kg) and also two doses of Scc. After two days, the effects of this treatment were investigated in the cerebral cortex, hippocampus, kidney, liver and urine samples of rats. We observed that N-Acetyl-β-d-glucosaminidase (NAG) activity in the kidney and urine was higher in MeHg-group when compared with the control group. Similarly, the lipid peroxidation levels were higher in the liver and kidney as well as the Adenosine deaminase (ADA) activity increased in the hippocampus, kidney and liver. These results indicate that increased NAG and ADA activities, as well as thiobarbituric acid reactive species (TBARS) levels may play a critical role in MeHg nephrotoxicity. The most relevant finding in our investigation was that acute MeHg treatment in neonatal rats caused liver and renal impairment and Scc was able to prevent such effects. It appears that mechanisms related to scavenging activity of Scc could be involved with its protection effect. Key words: Methylmercury; Syzygium cumini; N-Acetyl-β-d-glucosaminidase; rat; adenosine deaminase
O metilmercúrio (MeHg) é um agente tóxico potente tanto para o sistema nervoso central como para o renal. Provoca danos nos seres humanos e em ratos, particularmente durante o estágio de desenvolvimento. Neste estudo, ratos em desenvolvimento (P2) receberam uma dose única de MeHg (10 mg/kg), por via oral e/ou duas doses do extrato aquoso de sementes de Syzygium cumini (L.) Skeels (Scc). Após dois dias (P4), foram investigados os efeitos deste tratamento no córtex cerebral, hipocampo, rim, fígado e urina. Observamos que a atividade da N-acetil-β-d-glicosaminidase (NAG) nos rins e na urina foi maior no grupo que recebeu MeHg, quando comparado com o grupo controle. Da mesma forma, os níveis de peroxidação lipídica foram maiores no fígado e rim e a atividade da adenosina deaminase (ADA) encontrou-se elevada no hipocampo, rins e fígado, nos ratos tratados com MeHg. Estes resultados indicam que o aumento da atividade da NAG e da ADA, bem como os níveis das espécies reativas ao ácido tiobarbitúrico (TBARS), desempenham um papel importante como marcadores de nefrotoxicidade causada pelo MeHg. Assim, o achado mais relevante na nossa investigação foi a de que o tratamento agudo com MeHg em ratos neonatos pode provocar nefrotoxicidade e a administração do Scc pode reverter estes efeitos provavelmente devido as propriedades antioxidantes de Scc.

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O diabetes melito (DM) é um grupo heterogêneo de alterações metabólicas, caracterizado por hiperglicemia crônica, com alterações do metabolismo de carboidratos, ácidos graxos e proteínas. O diabetes melito tipo 2 (DMT2) é a forma mais comum dessa doença, acomentendo aproximadamente 90% dos indivíduos que apresentam DM. Caracteriza-se principalmente por modificações da ação e secreção de insulina, embora sua etiologia, genética e fisiopatologia específicas ainda não estejam completamente determinadas. Os pacientes com DMT2 apresentam maior risco de desenvolvimento de complicações macro e microvasculares. Estudos revelaram que a enzima conversora de angiotensina (ECA) e a adenosina deaminase (ADA) podem estar relacionadas ao desenvolvimento de DMT2 ou de suas complicações. Com base nesses dados, foram estudados os polimorfismos I/D do gene ECA e TaqI do gene ADA em 162 indivíduos com DMT2, e 160 indivíduos saudáveis. Segundo a Associação Americana de Diabetes, os indivíduos diabéticos que apresentam HDLc abaixo de 40mg/dl ou LDLc acima de 100 mg/dl ou triglicerídeos acima de 150 mg/dl apresentam maior risco de desenvolvimento de doenças cardiovasculares. Por isso, foram selecionados 81 indivíduos com essas características para compor o grupo de estudo de pacientes diabéticos com “risco de doença cardiovascular”. Os polimorfismos foram avaliados por PCR e PCR-RFLP para os genes da ECA e ADA respectivamente. As frequências obtidas para o polimorfismo do gene ECA foram: pacientes diabéticos: I/I (19,1%); I/D (52,5%); D/D (28,4%); grupo controle I/I (12,5%); I/D (55,6%); D/D (31,9%) e grupo de diabéticos com riscos de doença cardiovascular I/I (16%); I/D (59,3%); D/D (24,7%). E para o gene ADA: em pacientes diabéticos ADA*1/*1 (89,31%); ADA*1/*2 (10,06%); ADA*2/*2 (0,63%); grupo controle ADA*1/*1 (91,25%); ADA*1/*2 (7,50%); ADA*2/*2 (1,25%); pacientes...
Diabetes mellitus (DM) is a heterogeneous group of metabolic disorders characterized by chronic hyperglycemia, with changes in the carbohydrates, fatty acids and proteins metabolism. Diabetes mellitus type 2 (DMT2) is the most common form of this disease, that affect approximately 90% of people who have DM. It is characterized mainly by changes in the action and insulin secretion, although the etiology, genetics and specific pathophysiology of the disease is not yet completely determined. DMT2 patients have a higher risk of developing macro and microvascular complications. Studies have shown that angiotensin-converting enzyme (ACE) and adenosine deaminase (ADA) may be related to the development of DMT2 or its complications. Based on these data, we studied the polymorphisms I / D of the ACE gene and the polymorphism TaqI in the ADA gene, in 162 patients with DMT2, and 160 blood donors. According to the American Diabetes Association, people with diabetes who have HDL-C below 40 mg / dL or LDL-C above 100 mg / dl or triglycerides above 150 mg / dl are at increased risk of developing cardiovascular disease. Therefore, we selected 81 individuals with these characteristics to compose the study group of diabetic patients named “risk of cardiovascular disease . The polymorphisms are evaluated by PCR for ACE gene and PCR-RFLP for the ADA Gene. The frequencies obtained for the ACE gene polymorphism were: diabetic patients: I / I (19.1%), I / D (52.5%) and D / D (28.4%), control group: I / I ( 12.5%) I / D (55.6%) and D / D (31.9%) and group of patients with cardiovascular disease risk: I / I (16%) I / D (59.3% ), D / D (24.7%). And for the ADA gene polymorphism: in diabetic patients: ADA * 1 / * 1 (89.31%); ADA * 1 / * 2 (10.06%), ADA * 2 / * 2 (0.63%); control group: ADA * 1 / * 1 (91.25%); ADA * 1 / * 2 (7.50%); ADA * 2 / * 2 (1.25%), and patients with cardiovascular risk:... (Complete abstract click electronic access below)

Orientador: Luiz Carlos de Mattos
Banca: Antonio Carlos Pires
Banca: Haroldo Wilson Moreira
Resumo: O diabetes melito (DM) é um grupo heterogêneo de alterações metabólicas, caracterizado por hiperglicemia crônica, com alterações do metabolismo de carboidratos, ácidos graxos e proteínas. O diabetes melito tipo 2 (DMT2) é a forma mais comum dessa doença, acomentendo aproximadamente 90% dos indivíduos que apresentam DM. Caracteriza-se principalmente por modificações da ação e secreção de insulina, embora sua etiologia, genética e fisiopatologia específicas ainda não estejam completamente determinadas. Os pacientes com DMT2 apresentam maior risco de desenvolvimento de complicações macro e microvasculares. Estudos revelaram que a enzima conversora de angiotensina (ECA) e a adenosina deaminase (ADA) podem estar relacionadas ao desenvolvimento de DMT2 ou de suas complicações. Com base nesses dados, foram estudados os polimorfismos I/D do gene ECA e TaqI do gene ADA em 162 indivíduos com DMT2, e 160 indivíduos saudáveis. Segundo a Associação Americana de Diabetes, os indivíduos diabéticos que apresentam HDLc abaixo de 40mg/dl ou LDLc acima de 100 mg/dl ou triglicerídeos acima de 150 mg/dl apresentam maior risco de desenvolvimento de doenças cardiovasculares. Por isso, foram selecionados 81 indivíduos com essas características para compor o grupo de estudo de pacientes diabéticos com "risco de doença cardiovascular". Os polimorfismos foram avaliados por PCR e PCR-RFLP para os genes da ECA e ADA respectivamente. As frequências obtidas para o polimorfismo do gene ECA foram: pacientes diabéticos: I/I (19,1%); I/D (52,5%); D/D (28,4%); grupo controle I/I (12,5%); I/D (55,6%); D/D (31,9%) e grupo de diabéticos com riscos de doença cardiovascular I/I (16%); I/D (59,3%); D/D (24,7%). E para o gene ADA: em pacientes diabéticos ADA*1/*1 (89,31%); ADA*1/*2 (10,06%); ADA*2/*2 (0,63%); grupo controle ADA*1/*1 (91,25%); ADA*1/*2 (7,50%); ADA*2/*2 (1,25%); pacientes... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Diabetes mellitus (DM) is a heterogeneous group of metabolic disorders characterized by chronic hyperglycemia, with changes in the carbohydrates, fatty acids and proteins metabolism. Diabetes mellitus type 2 (DMT2) is the most common form of this disease, that affect approximately 90% of people who have DM. It is characterized mainly by changes in the action and insulin secretion, although the etiology, genetics and specific pathophysiology of the disease is not yet completely determined. DMT2 patients have a higher risk of developing macro and microvascular complications. Studies have shown that angiotensin-converting enzyme (ACE) and adenosine deaminase (ADA) may be related to the development of DMT2 or its complications. Based on these data, we studied the polymorphisms I / D of the ACE gene and the polymorphism TaqI in the ADA gene, in 162 patients with DMT2, and 160 blood donors. According to the American Diabetes Association, people with diabetes who have HDL-C below 40 mg / dL or LDL-C above 100 mg / dl or triglycerides above 150 mg / dl are at increased risk of developing cardiovascular disease. Therefore, we selected 81 individuals with these characteristics to compose the study group of diabetic patients named "risk of cardiovascular disease ". The polymorphisms are evaluated by PCR for ACE gene and PCR-RFLP for the ADA Gene. The frequencies obtained for the ACE gene polymorphism were: diabetic patients: I / I (19.1%), I / D (52.5%) and D / D (28.4%), control group: I / I ( 12.5%) I / D (55.6%) and D / D (31.9%) and group of patients with cardiovascular disease risk: I / I (16%) I / D (59.3% ), D / D (24.7%). And for the ADA gene polymorphism: in diabetic patients: ADA * 1 / * 1 (89.31%); ADA * 1 / * 2 (10.06%), ADA * 2 / * 2 (0.63%); control group: ADA * 1 / * 1 (91.25%); ADA * 1 / * 2 (7.50%); ADA * 2 / * 2 (1.25%), and patients with cardiovascular risk:... (Complete abstract click electronic access below)
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A adenosina desaminase (ADA â E.C.3.5.4.4.) à uma enzima fundamental no catabolismo das purinas. Ela catalisa a desaminaÃÃo da adenosina ou 2âdeoxi-adenosina produzindo amÃnia e inosina ou 2â-deoxi-inosina, respectivamente. Sua atividade à expressa por 2 isoenzimas presentes em 3 isoformas. A ADA1 (36kDa) ou ADA1 ligada ao CD26 (280kDa) sÃo amplamente distribuÃdas nos tecidos. Sua aÃÃo à particularmente importante porque altos nÃveis de 2âdeoxi-adenosina sÃo tÃxicos para as cÃlulas do sistema imunolÃgico. A ADA2 (100kDa) à normalmente encontrada no soro e sintetizada somente pelo sistema monocÃtico-macrofÃgico. A importÃncia biolÃgica da ADA2 ainda nÃo està totalmente estabelecida, principalmente devido as suas caracterÃsticas cinÃticas. O presente trabalho teve como objetivo discriminar as isoenzimas da adenosina desaminase humana atravÃs de eletroforese em gel de agarose e pelo modelo proposto por Vale e Almeida (1998), bem como realizar um estudo descritivo retrospectivo sobre o perfil dos exames de ADA no Estado do CearÃ. As amostras de lÃquido ascÃtico, pleural e pericÃrdico foram submetidas à eletroforese em agarose a 1% a 80 V por 7 horas. O gel foi fatiado e cada fatia foi incubada em adenosina (22 ou 0,55mM) por 20 horas para a detecÃÃo da amÃnia liberada pela reaÃÃo enzimÃtica. Os resultados encontrados a partir da eletroforese foram comparados com os resultados achados pelo modelo de Vale e Almeida (1998). O lÃquido pleural à o fluido que à mais frequentemente solicitado para a determinaÃÃo da ADA, seguido pelos lÃquidos ascÃtico, cefalorraquidiano, pericÃrdico e soro. Observamos que os valores de atividade enzimÃtica sÃo influenciados pelo tipo de lÃquido corporal onde a enzima se encontra, podendo estar relacionada Ãs barreiras corporais, tais como a barreira hematoencefÃlica. A partir dos resultados obtidos, podemos concluir que o modelo matemÃtico proposto pode ser usado em laboratÃrios clÃnicos para discriminar as isoenzimas da ADA.
Adenosine deaminase (ADA â E.C.3.5.4.4.) is a fundamental enzyme in the catabolism of the purines. It catalyzes the deamination of adenosine or 2âdeoxy-adenosine producing ammonium and inosine or 2â-deoxyinosine, respectively. Its activity is expressed by two isoenzymes presented in three isoforms. ADA1 (36 kDa) and ADA1 bound to CD26 (280kDa) are widely distributed in the body tissues. Their action is particularly important because high levels of 2âdeoxy-adenosine are toxic for the immune system cells. ADA2 (100kDa) is normally found in serum and is synthesized only in monocyte-macrophage system. The biological importance of ADA2 is not yet fully clear, especially for its kinetics characteristics. The objective of the present work was to discriminate the isoenzymes of human adenosine deaminase using agarose electrophoresis and by mathematical model proposed by Vale and Almeida (1998). In addition, we performed a study of the profile of ADA tests in State of Ceara (Brazil). Samples of of ascites, pleural and pericardial effusion were submitted to electrophoresis in 1% agarose at 80V for 7 hours. The gel was sliced and each slice was incubated in adenosine (22 or 0,55mM) for 20 hours to detect the ammonium released by enzymatic reaction. The results found from electrophoresis were compatible with the model proposed by Vale and Almeida (1998). The pleural fluid is the most frequently requested for the determination of ADA, followed by ascitic fluid, cerebrospinal fluid, pericardial fluid and serum. We observed that the value of enzymatic activity is influenced by corporal fluid type where the enzyme is localized. These data can be associated with the corporal barrier, like brain barrier. We concluded that the proposed mathematical model could be used in clinical laboratories to discriminate ADA isoenzymes to improve the diagnostic method.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.
Objectives: Diagnosis of pleural tuberculosis (PT) is still a challenge, particularly in resource-constrained settings. Alternative diagnostic tools are needed. We aimed at evaluating the utility of Clinical Prediction Rules (CPRs) for diagnosis of pleural tuberculosis in Peru. Methods: We identified CPRs for diagnosis of PT through a structured literature search. CPRs using high-complexity tests, as defined by the FDA, were excluded. We applied the identified CPRs to patients with pleural exudates attending two third-level hospitals in Lima, Peru, a setting with high incidence of tuberculosis. Besides pleural fluid analysis, patients underwent closed pleural biopsy for reaching a final diagnosis through combining microbiological and histopathological criteria. We evaluated the performance of the CPRs against this composite reference standard using classic indicators of diagnostic test validity. Results: We found 15 eligible CPRs, of which 12 could be validated. Most included ADA, age, lymphocyte proportion and protein in pleural fluid as predictive findings. A total of 259 patients were included for their validation, of which 176 (67%) had PT and 50 (19%) malignant pleural effusion. The overall accuracy of the CPRs varied from 41% to 86%. Two had a positive likelihood ratio (LR) above 10, but none a negative LR below 0.1. ADA alone at a cut-off of ≥40 IU attained 87% diagnostic accuracy and had a positive LR of 6.6 and a negative LR of 0.2. Conclusion: Many CPRs for PT are available. In addition to ADA alone, none of them contributes significantly to diagnosis of PT.

Determinar la utilitat de l’adenosina desaminasa (ADA) pleural per a diagnosticar vessament pleural tuberculós en població espanyola, segons la tècnica de mesura i punt de tall utilitzats, i comparar-la amb la descrita en altres poblacions. Mètodes: Meta-anàlisi d’estudis diagnòstics sobre ADA pleural en població espanyola, extrets de PubMed i Embase des dels seus inicis fins a juliol de 2017, sense restriccions de llenguatge. Es va analitzar l’eficàcia diagnòstica global de l’ADA, segons les tècniques de mesura (Giusti, mètodes cinètics manuals i mètodes cinètics automatitzats), i el punt de tall seleccionat. El QUADAS-2 va avaluar la qualitat dels estudis. Es va utilitzar un model bivariable d’efectes aleatoris. Es van comparar els resultats amb els descrits en meta-anàlisis previs sobre població no espanyola. Resultats: Es van incloure 16 estudis, amb 4147 pacients, dels que 1172 tenien un vessament pleural tuberculós. L’ADA va tenir una sensibilitat del 93%, especificitat del 92%, likelihood ratio (LR) positiva de 12, LR negativa de 0,08, i una àrea sota la corba de 0,968 per a identificar tuberculosi. No es van observar diferències d’eficàcia diagnòstica entre les diferents tècniques de mesura de l’ADA o el punt de tall triat. En 73 estudis de població no espanyola es va observar una tendència a una menor sensibilitat (88%, IC95% 86-90%) i especificitat (88%, IC95% 86-90%) de l’ADA, però les diferencies no van aconseguir significació estadística. Conclusions: L’ADA pleural en població espanyola te una bona precisió diagnòstica (independentment de la tècnica de mesura o punt de tall utilitzats), similar a la utilitzada en població no espanyola.
Determinar la utilidad de la adenosina desaminasa (ADA) pleural para diagnosticar derrame pleural tuberculoso (DPT) en población española, según la técnica de medición y punto de corte utilizados, y compararla con la descrita para otras poblaciones. Métodos: Meta-análisis de estudios diagnósticos sobre ADA pleural en población española, extraídos de PubMed y Embase desde sus comienzos hasta julio de 2017, sin restricciones de lenguaje. Se analizó la eficacia diagnóstica global de la ADA, según sus técnicas de medición (Giusti, métodos cinéticos manuales y métodos cinéticos automatizados), y el punto de corte seleccionado. La herramienta QUADAS-2 evaluó la calidad de los estudios. Se utilizó un método bivariante de efectos aleatorios. Se compararon los resultados con los descritos en meta-análisis previos sobre población no española. Resultados: Se incluyeron 16 estudios, con 4147 pacientes, de los que 1172 tenían un DPT. La ADA tuvo una sensibilidad del 93%, especificidad del 92%, likelihood ratio (LR) positiva de 12, LR negativa de 0,08, y área bajo la curva de 0,968 para identificar tuberculosis. No hubo diferencias de eficacia diagnóstica entre las técnicas de medición de ADA o el punto de corte escogido. En 73 estudios de población no española se observó una tendencia hacia una menor sensibilidad (88%, IC95% 86-90%) y especificidad (88%, IC95% 86-90%) de la ADA, pero las diferencias no alcanzaron significación estadística. Conclusiones: La ADA pleural en población española tiene una buena precisión diagnóstica (independientemente de la técnica de medición empleada o del punto de corte empleados), similar a la reportada en población no española.
To evaluate the utility of pleural adenosine deaminase (ADA) for diagnosing tuberculous pleural effusions (TPE) in the Spanish population, according to the laboratory technique employed and cutoff selected, and to compare it with that reported in other populations. Methods: Meta-analysis of diagnostic studies on pleural ADA in the Spanish population, which were extracted from the PubMed and Embase database from inception to July 2017, without language restrictions. The overall diagnostic accuracy of ADA and that of each of their tecniques of measurement (Giusti, manual and automated kinetic methods) and selected cutoffs were analyzed. The QUADAS-2 tool evaluated the quality of studies. A bivariate random effects model was used. Results were compared with those obtained from previous meta-analyses referring to non-Spanish populations. Results: Sixteen studies, totaling 4147 patients, of whom 1172 had TPE, were included. ADA had 93% sensitivity, 92% specificity, likelihood ratio (LR) positive of 12, LR negative of 0.08, and area under the curve of 0.968 for identifying tuberculosis. There were no differences in diagnostic accuracy between techniques used for ADA measurement or the selected cutoffs. In 73 studies from non-Spanish populations a trend toward a lower ADA sensitivity (88%, IC95% 86-90%) and specificity (88%, IC95% 86-90%) was noted, but differences did not reach statistical significance. Conclusions: Pleural ADA in the Spanish population has a meaningful diagnostic accuracy (regardless of technique used for measurement or cutoff selected), which is similar to that reported in non-Spanish populations.

The extracts of stem and root of the Uncaria tomentosa plant present several properties. Among them, the anti-inflammatory property is very important since it has been studied and widely observed in cases of rheumatoid arthritis (RA) treatment. The model of arthritis induced by complete Freund s adjuvant (CFA) in rats is a model widely used in searches for new therapies for chronic inflammatory arthropathies, such as RA, which in turn, is a chronic inflammatory disease, immune-mediated and with rather complex physiopathology. During the inflammatory process, a complex and hierarchical cytokines network rules this process triggering a Th1 type immune response. Among the mediators that modulate the action of lymphocytes during inflammatory process, we emphasize ATP, ADP, AMP and the nucleoside adenosine, which are essentials to the initiation and maintenance of inflammatory responses. The effects of these molecules are promoted by the action of specific purinergic receptors and controlled by an enzyme complex on the cell surface. The objective of this study was to evaluate the effect of the Uncaria tomentosa extract on the metabolism of adenine nucleotides through the activity of ectoenzymes involved in the ATP metabolism in lymphocytes of rats submitted to an experimental model of rheumatoid arthritis.The animals were divided into four groups, namely, control (C), extract (E), arthritis (AR) and arthritis associated with extract (AR+E). Fifteen days after AR induction by CFA, the U. tomentosa dry extract was administered two times a day at the dose of 150mg/kg for 45 days. After treatment, the blood was collected by cardiac puncture and the lymphocytes were isolated to E-NTPDase and ADA activity determination, and the serum used to purine level measurement. Results show an increase in the E-NTPDase activity in rats with CFA induced arthritis compared to control. Rats treated only with Uncaria tomentosa extract showed E-NTPDase and E-ADA activity maintained in basal levels. In rats with RA treated with Uncaria tomentosa, the extract was able to prevent the increase on the E-NTPDase activity, although the ATP and adenosine levels were decreased and ADP levels were increased in extracellular medium. The increase in E-NTPDase activity might be related to the attempt to maintain basal levels of ATP and ADP in basal levels in the extracellular medium, since the RA induction causes tissue damage and consequently large amounts of ATP in the cell. This way, the Uncaria tomentosa extract was able to prevent the increase in the E-NTPDase activity promoting RA induction.
Os extratos do caule e da raiz da planta Uncaria tomentosa possuem diversas propriedades, dentre elas a propriedade anti-inflamatória, sendo bastante utilizados em casos de artrite reumatóide (AR). O modelo de artrite induzida por adjuvante completo de Freund (CFA) em ratos é um modelo bastante empregado na investigação de novas terapias para artropatias inflamatórias crônicas, como a AR, que por sua vez, é uma doença crônica inflamatória, imunomediada e com fisiopatologia bastante complexa. Durante o processo inflamatório, uma rede complexa e hierarquizada de citocinas rege este processo desencadeando uma resposta imunológica essencialmente do tipo Th1. Dentre os mediadores capazes de modular as ações dos linfócitos, durante um processo inflamatório, destacam-se o ATP, o ADP, o AMP e o nucleosídeo adenosina, essenciais para o início e manutenção das respostas inflamatórias. Os efeitos destas moléculas são promovidos através da ativação de receptores purinérgicos específicos e controlados por um complexo enzimático localizado na superfície das células. O objetivo deste trabalho foi avaliar o efeito do extrato de Uncaria tomentosa no metabolismo de nucleotídeos da adenina através da atividade de ectoenzimas envolvidas na hidrólise do ATP em linfócitos de ratos submetidos a modelo experimental de AR. Os animais foram divididos em 4 grupos, controle (C), extrato (E), artrite (AR) e artrite associado ao extrato (AR+E). Quinze dias após a indução da AR por CFA, o extrato seco de U. tomentosa foi administrado por gavage 2 vezes ao dia na dose de 150mg/Kg durante 45 dias. Após o tratamento, o sangue foi coletado por punção cardíaca e os linfócitos foram separados para a realização da atividade da E-NTPDase e ADA, e o soro utilizado para a quantificação dos nucleotídeos e nucleosídeo. Os resultados demonstraram um aumento na atividade da E-NTPDase em ratos com AR induzida por CFA quando comparado ao controle. Já nos ratos tratados somente com o extrato de Uncaria tomentosa pode-se observar que o mesmo manteve a atividade da E-NTPDase e da E-ADA a níveis basais. Nos ratos com AR e tratados com o extrato pode-se observar que o mesmo foi capaz de prevenir o aumento da atividade da E-NTPDase, embora o nível de ATP e adenosina se encontram diminuídos e do ADP aumentado no meio extracelular. O aumento na atividade da E-NTPDase estaria relacionado com a tentativa de manter as concentrações basais de ATP e ADP no meio extracelular, uma vez que a indução da AR causa dano tecidual e consequentemente a liberação de grandes quantidades de ATP presentes no interior da célula. Dessa forma, o extrato de Uncaria tomentosa foi capaz de prevenir o aumento da atividade da E-NTPDase causado pela indução da AR.

Chez la Brebis, au cours de la gestation et de la lactation, l'évolution du métabolisme lipidique du tissu adipeux est caractérisée par 2 phases métaboliques successives et opposées. La prmière est une phase d'accumulation des réserves lipidiques (lipogénèse élevée, lipolyse aibl), elle correspond aux 2 premiers tiers de la gestation. La seconde est une phase de mobilisation des réserves lipidiques (lipogénèse faible, lipolyse élvée), elle englobe les périodes du dernier tiers de la gestation et du début de la lactation. Ce profil d'évolution du métabolism lipidique doit permettre à l'organisme maternel de subvenir d'une part aux besoins énergétiques importants du foetus en fin de gestation et d'autre part, de préparer et de aire face au coût énergétique très élevé de la lactation. En utilisant un système d'incubation d'adipocytes isolés maintenus en survie, ces derniers étant prélevés sur des Brebis en cours de gestation et de lactation, l'étude expérimental a porté sur l'évolution de la réponse cellulaire à l'action de différents effecteurs de la lipolyse. La sensibilité des adipocytes aux stimuli lipolytiques de l'isoprénaline (caté¬cholamine de synthèse) et de la théophylline (méthylxanthine) croît au cours de la gestation pour tendre vers un maximum à quelques jours "pré-partum". Pendant la 3ème semaine de lactation, les cellules demeurent à un niveau élevé de sensibilité. Le niveau de l'effet antilipolytique de l'adénosine est proportionnel à la sensibilité des cellules isolées au stimulus lipolytique de l'isoprénaline. Cet effet rétro-régulateur a été mis en évidence de manière directe en présence d'adé-nosine et d'isoprénaline et de manière indirecte en présence d'adénosine désaminase. Les actions sur la lipolyse de 2 hormones, l'hormone placentaire lactogène ovine (oPL) et l'hormone de croissance bovine (bGh) ont été testées. L'oPL ne présente aucun effet, la bGh présente en début de gestation un effet de potentialisation sur l'action lipolytique du couple isoprénaline-théophylline. La réorientation complète du métabolisme lipidique à partir de la fin du second tiers de la gestation se reflète dans l'évolution de la sensibilité cellulaire aux stimuli lipolytiques de l'isoprénaline et de la théophylline. Les rôles suggérés dans la littérature pour la bGh et l'oPL au sujet de leur action lipolytique demeurent très controversés.

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Metabolic syndrome (MetS) is a complex disorder represented by a set of cardiovascular risk factors, including endothelial dysfunction, oxidative stress and inflammation. Syzygium cumini has hypoglycemic, anti-inflammatory, antipyretic, hypolipidemic and antioxidant properties, besides antiviral and anticarcinogenic action. Considering the importance of MetS in the current economic and social context, morbidity and complications following this pathology, the aim of this study was to assess biochemical and inflammatory parameters in patients with MetS. Moreover, to check the effect of aqueous extract of Syzygium cumini (ASc), as well as its mechanism of action on the activity of the enzyme adenosine deaminase (ADA) and other biochemical parameters under hyperglycemic and oxidative conditions in vitro. To develop the first step of this work, were obtained samples of serum and whole blood of patients diagnosed with MetS (n=40) before initiating a physical activity program, in which we analyzed biochemical, oxidative and inflammatory parameters. The results showed an increase in ADA, acetylcholinesterase (AChE) and dipeptidyl peptidase IV (DPP-IV) activities in lymphocytes of patients with MetS. Further, in these patients, we observed an increase in the activity of butyrylcholinesterase (BuChE) and ˠ- glutamyltransferase (ˠ-GT) and in C-reactive protein (hsCRP) and nitric oxide (NOx) levels, as well as disturbances in antioxidant defenses and some correlations between the parameters analyzed were obtained. Thus, these results demonstrated that MetS affects the purinergic and cholinergic systems reflecting the inflammatory and immune status of these patients, besides altering the antioxidant defenses of the same. For in vitro determinations, first, erythrocytes (RBCs) from healthy individuals were used. ASc was able to prevent the increase in ADA activity caused by exposure of RBCs to hyperglycemic conditions for 2 hours. Also, ASc acted on the activity of ADA similarly caffeine and insulin, on the other hand, dipyridamole attenuated the effect of ASc by antagonizing its the effect or by competition with the extract. Thus, it can be suggested that the ASc act by influencing the metabolism of adenosine, and its effect is related to the presence of phenolic compounds and the antioxidant properties attributed to this plant. In the next step of this work , we observed an increase in the ADA activity and lipid peroxidation and decreased cell viability after exposure of lymphocytes from healthy subjects to 2,2 ' -azobis -2- amidinopropane dihydrochloride ( AAPH ) by 2 hours in vitro. ASc and gallic acid were able to reduce the ADA activity, but did not alter the lipid peroxidation caused by AAPH . The ASc increased cell viability and reduced the activity of the enzyme lactate dehydrogenase ( LDH ). ASc, by reducing the activity of ADA, may be increasing adenosine levels and helping to maintain the beneficial effects caused by the same, such as antioxidant, anti-inflammatory and antithrombotic actions. Furthermore, the results demonstrate the cytoprotective effect evidenced by the extract. We conclude that the changes found in patients with MetS are related to inflammatory and oxidative processes and may favor the prevention and control of this clinical situation Also, the protective effects demonstrated by ASc contribute to the understanding of the wide use of this plant and its therapeutic value in the treatment of various clinical conditions.
A Síndrome Metabólica (SMet) é um transtorno complexo representado por um conjunto de fatores de risco cardiovascular, entre eles a disfunção endotelial, o estresse oxidativo e a inflamação. O Syzygium cumini, conhecido popularmente como jambolão, é uma planta que apresenta propriedades hipoglicêmicas, antiinflamatórias, antipiréticas, hipolipidêmicas e antioxidantes, além de ação antiviral e anticarcinogência. Considerando a importância da SMet no contexto social e econômico atual, a morbidade e as complicações consequentes desta situação clínica, o objetivo deste estudo foi avaliar parâmetros bioquímicos e inflamatórios em pacientes com SMet. Além disso, verificar o efeito do extrato aquoso de Syzygium cumini (ASc), bem como o seu mecanismo de ação sobre a atividade da enzima Adenosina desaminase (ADA) e outros parâmetros bioquímicos sob condições hiperglicêmicas e oxidativas, in vitro. Para o desenvolvimento da primeira etapa deste trabalho, foram utilizadas amostras de soro e sangue total de pacientes com diagnóstico de SMet (40 pessoas) antes de iniciarem um programa de atividades físicas, nos quais foram analisados parâmetros bioquímicos, inflamatórios e oxidativos. Os resultados demonstraram um aumento na atividade das enzimas ADA, acetilcolinesterase (AChE) e dipeptidil peptidase IV (DPP-IV) em linfócitos de pacientes com SMet. Ainda, nesses pacientes, observou-se um aumento na atividade das enzimas Butirilcolinesterase (BuChE) e gama-glutamiltransferase (GGT), e nos níveis de proteína C reativa (PCR) e óxido nítrico (NOx), bem como alterações nas defesas antioxidantes e algumas correlações entre os parâmetros analisados foram obtidos. Assim, esses resultados demonstraram que a SMet afeta a atividade da ADA e o sistema colinérgico refletindo o estado imune e inflamatório desses pacientes, além de alterar as defesas antioxidantes dos mesmos. Para as análises in vitro, primeiramente, foram utilizados eritrócitos (RBCs) de indivíduos saudáveis. O ASc foi capaz de prevenir o aumento na atividade da ADA causado pela exposição dos RBCs a condições hiperglicêmicas por 2 horas. Ainda, o ASc atuou sobre a atividade da ADA de maneira semelhante a cafeína e a insulina; por outro lado, o dipiridamol atenuou o efeito do ASc por antagonizar o efeito do mesmo ou por competição com o extrato. Assim,pode-se sugerir que o ASc influencia no metabolismo da adenosina, além de seu efeito estar relacionado a presença de compostos fenólicos e às propriedades antioxidantes atribuídas a essa planta. Na etapa seguinte da realização deste trabalho, observou-se um aumento na atividade da ADA e na lipoperoxidação, e redução da viabilidade celular após a exposição de linfócitos de indivíduos saudáveis ao 2,2 -azobis (aminodipropano) dihidrocloreto (AAPH) por 2 horas, in vitro. O ASc e ácido gálico foram capazes de reduzir a atividade da ADA, mas não alteraram a lipoperoxidação causada pelo AAPH. O ASc aumentou a viabilidade celular e reduziu a atividade da enzima Lactato desidrogenase (LDH). O ASc ao reduzir a atividade da ADA, pode estar aumentando os níveis de adenosina e colaborando para a manutenção dos efeitos benéficos provocados pela mesma, como ações antioxidantes, antiinflamatórias e antitrombóticas. Além disso, os resultados demonstraram o efeito citoprotetor evidenciado pelo extrato. Podemos concluir que as alterações encontradas nos pacientes com SMet estão relacionadas aos processos inflamatórios e oxidativos e podem favorecer medidas de prevenção e controle desta situação clínica. Também, os efeitos protetores demonstrados pelo ASc contribuem para o entendimento da ampla utilização desta planta e de seu valor terapêutico no tratamento de diversas patologias clínicas.

L’ADA és un enzim del metabolisme purínic àmpliament distribuïda en els teixits humans. Durant molt de temps, s’ha considerat l’ADA com a enzim citosòlic, però recentment s’ha trobat també en la superfície de nombroses cèl•lules, fet que fa que sigui considerada, també, un ecto-enzim. L’ADA es pot unir a la superfície cel•lular mitjançant dos grups de proteïnes d’unió. Un grup és el format pels receptors d’adenosina. L’altre grup el constitueix el CD26, proteïna de membrana de tipus II, àmpliament distribuïda i amb activitat dipeptidil peptidasa IV (DPPIV). Recentment el grup ha demostrat que l’ecto-ADA s’expressa en la superfície de les cèl•lules dendrítiques (DC), mitjançant la seva unió als receptors A2B d’adenosina. Així, l’ecto-ADA expressada a la superfície de les DC, pot unir-se al CD26 expressat en cèl•lules T, per produir una senyal coestimuladora durant la sinapsi immunològica que resulta en una major activació, proliferació i secreció de citocines pro-inflamatòries i de tipus Th-1. Donada la clara rellevància de l’ecto-ADA en processos immunitaris i l’experiència del grup de recerca en l’estudi d’aquesta molècula com a ecto-enzim, s’ha plantejat el següent objectiu general: Estudiar l’efecte co-estimulador de l’ADA en la immunosinapsi produïda per interacció de cèl•lules T i cèl•lules dendrítiques de donants sans o infectats pel VIH Resultats referents a aquest objectiu • L’ADA actua sobre les iDCs d’individus sans i de pacients infectats pel VIH, incrementant l’expressió de CD80, CD83, CD86, CD40 i CCR7, i l’alliberament de IL-12, IL-6, TNF-α, IL-8/CXCL8, MIP1-α/CCL3, MIP-1β/CCL4 i RANTES/CCL5, fet compatible amb una major maduració de la DC. • L’ADA potencia l’activació de cèl•lules T CD4+CD45RA+ naïve, incrementant la generació de cèl•lules CD4+CD25+CD45RO+ efectores, cèl•lules CD4+CD45RACD25-CD45RO+ memòria i cèl•lules CD4+CD25HIFOXP3+ reguladores. Aquests efectes s’observen tant en donants sans com en una cohort de pacients infectats pel VIH. Un dels fets més esperançadors en la recerca en el camp del VIH és la identificació d’individus que tot i estar exposats repetidament a la infecció per VIH, no resulten infectats (EU). És també coneguda l’existència d’individus que tot i resultar infectats, controlen la infecció en absència de tractament (controllers). Les α-defensines són molècules de la immunitat innata, característiques de granulòcits com ara els neutròfils. Donada la seva elevada càrrega positiva generen porus en diferents membranes biològiques, sent capaces d’eliminar una amplia varietat de patògens, entre els que s’inclouen virus amb envolta com el VIH. Recentment s’ha descrit la capacitat de les DCs derivades de monòcit de produir i secretar a-defensines per la qual es postula el següent objectiu general: Estudiar la producció defensines per part de cèl•lules dendrítiques com a possible mecanisme innat de resistència a la infecció per VIH. Resultats referents a aquest objectiu: • Les iDCs de pacients controllers secreten nivells més elevats d’α-defensines 1-3 que les procedents de pacients que no mostren aquesta capacitat (no controllers) o que els individus sans. Aquests nivells correlacionen amb l’expressió de marcadors clínics indicatius de menor progressió cap a SIDA. • La cohort EU mostra una major freqüència de còpies del gen DEFA1A3 que la cohort d’individus sans o infectats pel VIH. Aquest fet es correlaciona amb una major secreció d’α-defensines 1-3.
Adenosine Deaminase (ADA) is an enzyme involved in the purine metabolism, degrading adenosine to inosine. Classically considered a cytosolic enzyme, ADA is also present on cell membranes , including immune cells. Not being an integral membrane protein, ADA needs association with other membrane proteins, such as CD26. This interaction was proposed to deliver costimulatory signals to T-cells. ADA was shown to colocalize with A2B receptors in human dendritic cells (DC) surface, where ADA bound to DC surface by means of A2B receptors could cross-link CD26 on T-cell membrane, delivering costimulatory signals resulting in increased T-cell proliferation and cytokine secretion. This Thesis shows that ADA increases the switch from CD4+ CD45RA+ naïve T-cells towards CD4+ CD45RO+ effector and memory T-cells, both in healthy and in HIV-infected individuals in a non-enzymatic dependent fashion. Additionally, we identified the novo generation of a subset of CD4+ CD25HI FOXP3+ T-cells (Tregs). The total numbers of this population was increased in the presence of ADA, both in healthy and in HIV-infected patients. Culturing immature DCs in the presence of ADA for 48h resulted in an increased expression of costimulatory CD80, CD86, CD83 and CD40 while not changing antigen presenting molecules such as HLA-DR or HLA-ABC. ADA presence resulted in increased IL-6, IL-12, TNF-α, IL-8 cytokine and CCL2-5 chemokine secretion One of the most promising advances in the HIV field over the last decade is the identification of individuals who naturally control the HIV infection (controllers) or who despite being exposed do not get infected (EU). α-defensins 1-3 (HNP1-3) are immune innate effector proteins with a broad antimicrobial potential, including the HIV. Their expression is highly variable and the genes encoding for HNP1-3 (DEFA1A3) show copy number variation (CNV), mostly ranging from 2 to 10 copies. Previous work showed that iDCs also secrete these peptides. In this Thesis HNP1-3 secretion was addressed in DC supernatants and found to be higher in HIV-infected individuals. In addition, patients expressing levels of HNP1-3 above 650 pg/ml, showed a slower disease progression. EU cohort showed increased copy numbers of DEFA1A3 gene, and correspondingly, its iDCs showed increased secretion of HNP1-3 peptides. High DEFA1A3 CNV individuals showed increased maturation and cytokine secretion profiles.

In our studies we found that stabilized expression of HIF-1α in heart led to better recovery of function and less tissue death after 30 minutes of global ischemia, via mechanisms that preserve the mitochondrial polarization. Our group previously showed that HIF-1α conferred ischemic tolerance by allowing cardiomyocytes to use fumarate as an alternative terminal electron acceptor to sustain anaerobic mitochondrial polarization. The source of fumarate was identified as the purine nucleotide cycle (PNC). Here we discovered that HIF-1α upregulates AMP deaminase 2 (AMPD2), the entry point to the PNC. The combination of glycolysis and the PNC may protect the heart's nucleotide resources. We subsequently examined the effects that HIF-1α exerts on nucleotide metabolism in the ischemic heart. We found that HIF-1α expression reduces adenosine accumulation in the ischemic heart. As ATP is depleted during ischemia, AMP accumulates. Our results suggest that AMP metabolism is shunted towards AMPD2 rather than the adenosine producing 5'-nucleotidase pathway. Subsequently, we treated hearts with the PNC inhibitor hadacidin followed by 30 minutes of global ischemia. Inclusion of hadacidin reduced ATP and adenylate energy charge in the hearts. These findings allow us to propose that activity of the PNC prevents the F0F1 ATP synthase from consuming glycolytic ATP in order to maintain mitochondrial polarization during ischemia. Thus, the PNC provides ATP sparing effects and preserves the energy charge in the ischemic heart. The fact that ATP and adenylate energy charge is better preserved during the initial 20 minutes of ischemia in HIF-1α expressing hearts is supportive of our observation that HIF-1α upregulates the PNC. HIF-1α also upregulates adenosine deaminase, which degrades adenosine. The limitation of adenosine accumulation may help HIF-1α expressing hearts avoid toxicity due to chronic adenosine exposure. Finally, we found that HIF-1α induces the expression of the nucleotide salvage enzyme hypoxanthine phosphoribosyl transferase (HPRT). Upon reperfusion HPRT serves to reincorporate the nucleotide degradation product, hypoxanthine, into the adenylate pool and may prevent the production of reactive oxygen species. Collectively, HIF-1α robustly protects the heart from ischemic stress and it upregulates several pathways whose cardioprotective role may extend beyond the remodeling of nucleotide metabolism.

A prospective study was undertaken to assess the diagnostic value of various rapid diagnostic tests for tuberculosis in pleural fluid, and to assess the sensitivity and speed of a radiometric mycobacterial culture system (BACTEC, Johnson Laboratories). Patients presenting to the Department of Medicine at Groote Schuur Hospital with pleural effusions for diagnostic pleural aspiration and biopsy over a 6 month period were entered into the study. Because the incidence of tuberculous effusions was observed to be high in this population (65% of 94 patients), patients from the Department of Radiotherapy with proven malignant disease and the development of new pleural effusions requiring diagnostic or therapeutic aspiration were included in the study in order to increase the number of control patients without tuberculosis. The 111 patients (17 of whom were recruited from the Department of Radiotherapy) were divided into 4 diagnostic categories: tuberculosis - 62 patients, malignant - 28 patients, miscellaneous conditions - 10 patients, and undiagnosed - 11 patients (3 of whom probably had tuberculosis). There were 59 male patients. The racial distribution was 11 whites, 51 of mixed race, and 49 blacks. Exudative pleural effusions were present in 109 patients. Closed pleural biopsies with the Abrams needle were performed on 100 patients using a modified version of the standard technique whereby larger specimens were obtained by stripping pleura off the chest wall. Seven pleural biopsies were reported as inadequate by the pathologist and the diagnostic yield of the procedure was 63%. Tuberculosis was confirmed histologically or by culture in 62 patients. The age distribution of these patients was bimodal, with most cases occuring in the third decade. The presentation was usually acute, with 60% of patients being symptomatic for less than 4 weeks. Granulomata were found on initial pleural biopsy in 52 cases (84%). Pleural biopsy culture was positive in 44 cases (71%). The radiometric culture system tested (12B BACTEC) yielded the same number (14) of positive cultures as conventional mycobacterial culture media in pleural fluid, but was almost twice as fast. Bedside inoculation of pleural fluid into 13A BACTEC bottles more than doubled the yield in the 24 patients tested (11 positive cultures compared with 4 each for conventional and 12B BACTEC media, p=0.046). The rapid diagnostic tests assessed on pleural fluid were adenosine deaminase (ADA), an antigen (BCG) capture enzymelinked immunosorbent assay (ELISA), and a specific DNA probe after amplification with the polymerase chain reaction. ADA was found to have a sensitivity of 0.77 and a specificity of 0.83 in the 109 patients tested, and values were significantly higher in tuberculosis patients compared with the other three diagnostic categories (p< 0.001 ). The ELISA test was performed on 103 patients and showed a sensitivity of only 0.26 and a specificity of 0.72. The DNA probe was performed on 43 patients, and had a sensitivity of 0.93 with a specificity of 0.43. Contamination of samples or latent tuberculous infection may have been responsible for the poor specificity of the DNA probe.

Aproximadamente unos 33 millones de personas están infectadas por el VIH en todo el mundo. No obstante, gracias al desarrollo de tratamientos antirretrovirales de alta eficacia (HAART), el SIDA se convirtió en una enfermedad crónica. Sin embargo, el HAART tiene efectos secundarios que afectan a la calidad de vida de los infectados. Por eso es necesaria una cura o una vacuna preventiva. Dadas las dificultades en desarrollar una vacuna preventiva es necesario ensayar nuevas estrategias terapéuticas. La adenosina desaminasa (ADA) es una enzima del metabolismo de las purinas. Actualmente se conocen dos grupos de proteínas de unión a ADA a la membrana plasmática: el CD26 y los receptores de adenosina. Las primeras evidencias de que el complejo CD26-ADA podía ejercer un papel en la activación linfocitaria se obtuvieron al observar un incremento en la expresión de CD26 y ecto-ADA en linfocitos T activados a través del TCR/CD3. Por otra parte, también se ha sugerido que la unión de ADA a CD26 posibilitaría la degradación extracelular de adenosina, eliminando de este modo señales inhibidoras para el sistema inmunitario. Por ello se puede hipotetizar que el efecto coestimulador por la unión de ADA a CD26 y la actividad adenosina desaminasa extracelular estarían implicadas en la activación linfocitaria. Nuestro grupo de investigación demostró la presencia de ADA en la superficie de las células dendríticas (DCs) humanas. Ésta co-localizaba principalmente con los receptores A2B de adenosina. Por ello se formuló la hipótesis de que la unión de ADA a la DC a través de los receptores A2B y simultáneamente a los linfocitos T a través del CD26 actuaría de puente, coestimulando al linfocito T. Además, se demostró, que el papel coestimulador de la ADA también ocurre en individuos infectados por el VIH. Todo ello permitió formular la hipótesis general de esta Tesis de que la ADA podría incrementar la respuesta de las células T en vacunas terapéuticas basadas en la presentación del VIH inactivado por parte de las DCs. Al determinar el papel de la ADA en la modulación de la función de las DCs, se observó que la ADA activa la maduración en las células dendríticas de individuos sanos e infectados por el VIH. Incrementando de esta manera la inmunogenicidad de las DCs tanto en individuos sanos e infectados por el VIH. Al investigar el efecto de la ADA en la generación de células T efectoras, memoria o reguladoras en co-cultivos autólogos de linfocitos T y DCs de individuos sanos e infectados por el VIH, se observó que la ADA potencia la diferenciación de las células T naive a células T efectoras y de memoria, además de potenciar la generación de células T reguladoras (Tregs) a partir de células T naive. Finalmente, se determinó los mecanismos por los cuales la ADA afecta la generación de células T efectoras CD4+ o CD8+, memoria y reguladoras en co-cultivos autólogos de linfocitos T y DCs presentadoras de virus VIH inactivado. Se observó que la ADA, en individuos sanos, la ADA disminuye de forma considerable el número de Tregs e inhibe su actividad supresora. Además, la ADA muestra una función dual disminuyendo la población Tregs específicas del VIH pero potenciando a las células T CD4+ efectoras específicas del VIH en individuos infectados por el VIH. Además, la ADA incrementa la proliferación de las células T CD8+ específicas del VIH, la generación de CD4+ y CD8+ de memoria específica del VIH y la secreción de citocinas y quimiocinas Th1/pro‐inflamatorias. Globalmente, la ADA actuaría como molécula coestimuladora en la inmunosinapsis, promoviendo una correcta polarización de las células T. Además, en el contexto de la infección por el VIH, la capacidad de la ADA de incrementar la inmunogenicidad de las DCs, de promover la correcta polarización de las células T efectoras específicas del VIH y su capacidad de inhibir la supresión mediada por Tregs inducidas por el VIH, hacen de la ADA un buen candidato como adyuvante en vacunas terapéuticas contra el VIH.
Currently, 33 million people are estimated to be infected with HIV worldwide. HIV infection is nowadays chronic and incurable, resulting in the need for continued therapy to maintain clinical stability. In this regard, several strategies are being considered for the development of either a prophylactic or a therapeutic vaccine. Adenosine deaminase (ADA) is a key enzyme in the purine metabolism pathway. ADA function is essential in maintaining an immune response as patients with ADA deficiency suffer from Severe Combined Immunodeficiency Disease (SCID). ADA is released into the extracellular medium by immune cells where can bind to two different types of membrane proteins such as CD26, and adenosine receptors. Extracellular ADA mediates extracellular adenosine degradation and acts as a costimulatory molecule in T‐cell activation processes. Our group found that ADA, by acting as a bridge between A2B adenosine receptors on dendritic cells (DCs) surface and CD26 on T‐cells surface, ADA acts as a costimulatory molecule. In addition, it was demonstrated that this costimulatory effect also occurs in HIV infected individuals. Therefore, the general hypothesis of this Thesis was that ADA could increase the T cell response in HIV therapeutic vaccines based in DCs presenting inactivated HIV. When determining the role of ADA in the modulation of DCs, it was found that ADA enhances DCs costimulatory molecule expression, increases the secretion of both proinflammatory cytokines and chemokines that are known to promote Th1 immune responses and ADA globally enhances the immunogenicity of human DC. Furthermore, ADA enhances the differentiation of naïve T cells into T effector and memory cells and enhances the generation of T regulatory cells from naïve T cells. Finally, ADA shows a dual role inhibiting the HIV-specific Tregs while enhancing HIV-specific T effector CD4+ cells in HIV-infected individuals. Moreover, ADA increases the proliferation HIV-specific T CD8+, the generation of HIV-specific memory Tcells and the secretion of Th1/pro-inflammatory cytokines and chemokines. Globally, the ability of ADA to increase the DCs immunogenicity, to promote the correct polarization of HIV-specific T-cells and to inhibit the suppression mediated by HIVspecific Tregs, makes ADA a good candidate as an adjuvant in HIV therapeutic vaccines.

O transplante renal representa atualmente a melhor opção terapêutica e de reabilitação para o paciente com insuficiência renal crônica terminal. As rejeições são as principais causas de perda dos rins transplantados e, entre essas, as rejeições agudas são as que apresentam maior relevância clínica. Desta maneira, a monitorização do transplante renal com vistas ao diagnóstico precoce da rejeição e seu rápido tratamento é de grande relevância no manejo adequado desses pacientes. Como a rejeição celular aguda é mediada predominantemente por linfócitos T e, visto que, a enzima adenosina deaminase (ADA) é encontrada principalmente, a nível de sangue periférico, em linfócitos, objetivou-se com esse estudo, verificar a possível associação entre atividade sérica da ADA e a rejeição aguda do enxerto renal. Buscou-se, também, determinar a sua utilidade como método diagnóstico de rejeição celular aguda. Foram acompanhados até 1 mês de internação 35 pacientes transplantados renais. Dosagens da atividade de ADA sérica foram feitas cinco vezes por semana e sempre que houvesse suspeita clínica de rejeição aguda. O diagnóstico de rejeição aguda foi estabelecido por 2 nefrologistas, aos quais foram omitidos os resultados dos níveis séricos ADA. Estes médicos tinham todas informações clínicas e laboratoriais, incluindo valores séricos de creatinina e ciclosporina, cintilografias, ecografias, citologia aspirativa, punção biópsia renal quando esta era realizada e resposta aos diferentes tratamentos imunossupressores usados. A análise estatística foi feita utilizando-se testes de Mann-Whitney e Qui-quadrado. O nível p menor do que 0,05 foi considerado como significativo. A mediana dos episódios de rejeição celular aguda ficou entre o sexto e sétimo dia pós-transplante, havendo diferença estatisticamente significativa nos valores de ADA no sexto dia de seguimento entre os pacientes com rejeição (60.16), em relação aos que não tiveram rejeição celular aguda (24,55) (p=0,021 MW). Para se avaliar a eficácia da atividade sérica de ADA com método diagnóstico de rejeição aguda, empregou-se pontos de corte de valores de ADA>35,>40,>45, >50 e > que 30% dos valores do período pré-rejeição. Houve associação estatisticamente significativa entre ADA>30% e rejeição celular aguda (p=0.035 MW). Verificou-se, também, aumento significativos da atividade sérica de ADA em pacientes anti-HCV positivos e com necrose tubular aguda, sem interferência sobre os resultados dos episódios de rejeição celular aguda. Usando esses pontos de corte como parâmetros de diagnóstico para rejeição aguda observou-se: sensibilidade = 55,5%, especificidade = 82,3%, valor preditivo positivo = 76,9%, valor preditivo negativo = 63,6% e acurácia = 69,0%. Conclui-se que há um aumento significativo da atividade sérica da ADA durante os episódios de rejeição aguda de enxertos renais humanos, encontrando-se associação significativa entre o aumento de 30% dos valores de ADA pré-rejeição e o diagnóstico de rejeição celular aguda.

The detennination of serum levels of adenosine deaminase (ADA), enzyme produced by monocytes/macrophages and lymphocytes, has been used in the diagnosis of human tuberculosis. In the present study, senmi activity of ADA was tested as a complementary test in the diagnosis of bovine tuberculosis. Two hundred fifty-six animals were classified by the comparative skin test using bovine and avian PPDs in reactors (52 animals), from herds where the Mvcobacterium bavis had previously been isolated. and non-reactors (204), from tuberculosis-tree herds. Mean ADA semm values from reactor animals (4.45 +/- 2.33 U/l) were signiiicantly smaller (p=0.008) then those observed in sera from non-reactor animals (6.12 +/-4.47 U/l). When non-reactor animals from a herd with clinical cases of bovine enzootic leukosis were withdrawn from analysis, the mean ADA serum values of the non-reactor group (5.12 +/- 3.75 U/1) was not different from that of the reactor group (p=0.28). Using two different cut0H points, 6.12 U/l and 15 U/l, there was no agreement between the determination of ADA serum values and the comparative skin test in the detection of tuberculous animals (kappa = -0.086 and kappa = -0.082, respectively). In conclusion, the determination of ADA serum activity was not a good complementary test for bovine tuberculosis, because it was not possible to distinguish skin test reactors and non-reactors by ADA serum levels.
A determinação dos níveis de adenosina deaminase (ADA) no soro sanguíneo, enzima produzida principalmente por células linfóides, tem sido utilizada no diagnóstico da tuberculose humana. A atividade da ADA foi testada neste trabalho, como possível método auxiliar no diagnóstico da tuberculose bovina. Pela tuberculinização intradérmica comparada, empregando-se tuberculinas PPD bovina e aviária, foram caracterizados dois grupos: animais reagentes (n=52), provenientes de propriedades onde o M. bovis já havia sido isolado, e animais não reagnetes (n=204), provenientes de propriedades livres de tuberculose bovina. Soros destes 256 bovinos foram submetidos à determinação de ADA, obtendo-se valores séricos de 4,45 +/- 2,33 U/I no grupo de animais reagentes e de 6,12 +/- 4,47 U/I, não houve concordância entre os dois métodos diagnósticos na detecção de animais tuberculosos (kappa=0,086 e kappa=0,082, respectivamente). Pelos resultados, conclui-se que a determinação da atividade de ADA no soro de bovinos não foi um bom método auxiliar no diagnóstico da tuberculose bovina, uma vez que a dosagem da atividade de ADA no soro não permitiu distinguir animais reagentes de não reagentes à tuberculinização.

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The purinergic system, especially adenosine, can play a role in the pathophysiology of schizophrenia. Activation of adenosine A1R inhibits the release of several neurotransmitters, such as glutamate, dopamine, serotonin and acetylcholine, and decreases neuronal activity by pos-synaptic hyperpolarization. Adenosine deaminase (ADA) paticipates in purine metabolism by converting adenosine into inosine. The most frequent functional polymorphism of ADA (22 G→A) (ADA1 *2) exhibits 20-30% lower enzymatic activity in individuals with the G/A genotype than individuals with the G/G genotype. We evaluated this polymorphism in 152 schizophrenic patients and 111 healthy controls. We observed a significant decrease in frequency of the low-activity ADA1 *2 allele in schizophrenic patients (7 – 4. 6%) relative to controls (13 – 11. 7%, p= 0. 032, OR=2. 6). These results suggest that ADA1 *2 allele associated with low ADA activity, and putatively with higher adenosine levels, is less frequent among schizophrenic patients.
O sistema purinérgico, especialmente a adenosina, pode desempenhar um papel na patofisiologia da esquizofrenia. A ativação dos receptores de adenosina A1 inibe a liberação de vários neurotransmissores como o glutamato, a dopamina, a serotonina e a acetilcolina, e diminui a atividade neuronal pela hiperpolarização pós-sináptica. A adenosina (ADA) participa no metabolismo da adenosina convertendo-a em inosina. O polimorfismo funcional mais freqüente da ADA (22 G→A) (ADA1 *2) exibe 20-30% menos atividade enzimática em indivíduos com o genótipo G/A do que em indivíduos com o genótipo G/G. Esse polimorfismo foi avaliado em 152 pacientes esquizofrênicos e 111 controles saudáveis. Nós observamos uma diminuição significativa na freqüência do alelo de baixa atividade ADA1 *2 em pacientes esquizofrênicos (7 – 4,6%) em relação aos controles (13 – 17%, p= 0,032, OR= 2,6). Esses resultados sugerem que o alelo ADA1 *2 associado à baixa atividade da ADA, e conseqüentemente a altos níveis de adenosina, é menos freqüente entre os pacientes esquizofrênicos.

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Benzodiazepines, such as diazepam and midazolam, are a widely used class of drugs for anxiety treatment, with anxiolytic, hypnotic, and anticonvulsant properties. The use of zebrafish (Danio rerio) as a model for evaluating pharmacological mechanisms has gained importance due to their rapid development and high sensitivity to drugs. Studies have shown that behavioral parameters were altered in zebrafish after benzodiazepine treatment. Many neurotransmitter systems have been identified in this species, including purinergic and cholinergic system. Purinergic system is characterized by the action of ATP and adenosine on purinoreceptor P2 and P1, respectively. The levels of these molecules are regulated by ectonucleotidases, especially nucleoside triphosphate diphosphohydrolase (NTPDases) and ecto-5'-nucleotidase, which constitute the extracellular cascade for ATP hydrolysis to adenosine. Adenosine can be subsequently deaminated to inosine by action of adenosine deaminase (ADA). ATP is coreleased with other neurotransmitters, including acetylcholine, and has been demonstrated that adenosine can control the release of acetylcholine. Cholinergic system is characterized by the action of acetylcholine (ACh) on muscarinic and nicotinic receptors. The level of this molecule is regulated by acetylcholinesterase (AChE), which catalyzes degradation of ACh into choline and acetate. Since there are few reports relating these enzyme activities and the action mechanism of benzodiazepines, the aim of this study was evaluated the in vitro and ex vivo effects of classical benzodiazepines, such as diazepam and midazolam, on NTPDase, ecto-5'nucleotidase, ADA, and AChE activities in zebrafish brain and gene expression pattern in treatments that induced changes in enzyme activity in the ex vivo experiments. In order to elucidate whether diazepam or midazolam has direct effects on these enzymes, we performed in vitro experiments. Diazepam, at 500 μM, promoted a decrease on ATP hydrolysis (66%), whereas this drug, at 10-500 μM, reduced ADP hydrolysis (40-54%, respectively). Midazolam also decreased ATP (16-71% for 10-500 μM, respectively) and ADP hydrolysis (48-73% for 250-500 μM, respectively), and ecto-ADA activity (26-27. 5% for 10-500 μM, respectively). Diazepam and midazolam did not induce significant changes on ecto-5´-nucleotidase activity at the concentrations tested. Concerning to AChE activity, 500 μM diazepam promoted a decrease on ACh hydrolysis (19%), whereas midazolam, at 50-500 μM, reduced AChE activity (18-79%, respectively). For ex vivo experiments, diazepam or midazolam exposures did not alter NTPDase activities in zebrafish brain membranes. AMP hydrolysis was decreased in animals treated with of 0. 5 and 1mg/L midazolam (31. 5% and 36. 1%, respectively) when compared to the control group. However, diazepam was unable to alter ecto-5’-nucleotidase. Both drugs significantly decreased the ecto-ADA activity, whereas diazepam and midazolam reduced the adenosine hydrolysis at a concentration of 1. 25 mg/L (30. 85%) and 1 mg/L (32. 8%), respectively. Diazepam did not alter cytosolic-ADA activity; however, the exposure to 0. 1 mg/L midazolam induced a significant increase in cytosolic-ADA (39. 9%) when compared with the control group. The gene expression pattern demonstrated that the CD73 transcript levels were increased (41. 7%) after treatment with 0. 5 mg/L midazolam. Moreover, the changes caused by diazepam and midazolam in the ADA activity are not related to the transcriptional control. Concerning the cholinerg signaling, diazepam decreased ACh hydrolysis at 1. 25 mg/L (30. 7%) when compared to the control group. Similarly, the exposure to 0. 5 mg/L midazolam also changed the enzymatic activity of 9 AChE promoting an increase in the ACh hydrolysis (36. 7%). It is possible to suggest that these drugs can induce a direct effect on the enzyme activities, since we observed a decreased on nucleotide and nucleoside hydrolysis after in vitro exposure. In addition, the alteration on AMP hydrolysis, ADA and AChE activities suggest a modulation of extracellular adenosine and ACh levels induced by benzodiazepine exposure.
Fármacos benzodiazepínicos, como diazepam e midazolam, são muito usados na prática clínica para o tratamento da ansiedade, possuindo propriedades ansiolíticas, hipnóticas e anticonvulsivantes. O uso do zebrafish (Danio rerio) como modelo para avaliar mecanismos farmacológicos tem ganhado grande importância devido ao rápido desenvolvimento e alta sensibilidade a drogas que essa espécie possui. Estudos têm demonstrado que parâmetros comportamentais mostraram-se alterados em zebrafish após tratamento com benzodiazepínicos. Muitos sistemas de neurotransmissão foram identificados nessa espécie, incluindo os sistemas purinérgico e colinérgico. O sistema purinérgico é caracterizado pela ação do ATP e adenosina (ADO) nos purinoreceptores P2 e P1, respectivamente. Os níveis dessas moléculas são regulados pela ação das ectonucleotidases, especialmente as nucleosídeo trifosfato difosfoidrolases (NTPDases) e a ecto-5’-nucleotidase, que catalisam a hidrólise do ATP a adenosina. A adenosina pode ser desaminada a inosina pela ação da adenosina desaminase (ADA). O ATP é coliberado com outros neurotransmissores, entre eles a acetilcolina, e tem sido demonstrado que a adenosina pode controlar a liberação de acetilcolina. O sistema colinérgico é caracterizado pela ação da acetilcolina (ACh) nos receptores muscarínicos e nicotínicos. O nível dessa molécula é regulado pela acetilcolinesterase (AChE), que catalisa a degradação da ACh em colina e acetato. Uma vez que existem poucos relatos relacionando esses sistemas enzimáticos e a ação de fármacos benzodiazepínicos, o objetivo deste estudo foi avaliar o efeito in vitro e ex vivo do tratamento com fármacos benzodiazepínicos, tais como diazepam e midazolam, sobre a atividade das NTPDases, ecto-5'-nucleotidase, ADA and AChE no encéfalo de zebrafish e o padrão de expressão gênica nos tratamentos que induziram alterações na atividade enzimática nos experimentos ex vivo. A fim de elucidar se o diazepam e o midazolam têm efeitos diretos nessas enzimas, experimentos in vitro foram realizados. Na concentração de 500 μM, o diazepam diminuiu a hidrólise de ATP (66%) e, nas concentrações de 10-500 μM, este fármaco reduziu a hidrólise de ADP (40-54%, respectivamente). O midazolam também diminuiu a hidrólise do ATP (16-71% para 10-500 μM, respectivamente), ADP (48-73% para 250-500 μM, respectivamente) e a atividade da ecto-ADA (26-27,5% para 10-500 μM, respectivamente). Diazepam e midazolam não induziram alterações significativas sobre a atividade da ecto-5´-nucleotidase nas concentrações testadas. Com relação à atividade da AChE, o diazepam, 500 μM, promoveu uma diminuição na hidrólise de ACh (19%) e o midazolam, nas concentrações de 50-500 μM, reduziu a atividade da AChE (18-79%, respectivamente). Nos experimentos ex vivo, as exposições ao diazepam e midazolam não alteraram a atividade enzimática das NTPDases em membranas cerebrais de zebrafish. A hidrólise do AMP diminuiu em animais tratados com 0. 5 mg/L e 1 mg/L de midazolam (31. 5% e 36. 1%, respectivamente) quando comparados com o grupo controle. Entretanto, o diazepam foi incapaz de alterar a atividade da ecto-5’-nucleotidase. Ambos os fármacos diminuíram significativamente a atividade da ecto-ADA, sendo que o diazepam e o midazolam reduziram a hidrólise da adenosina na concentração de 1. 25 mg/L (30. 85%) e 1 mg/L (32. 8%), respectivamente. O diazepam não alterou a atividade da ADA citosólica, no entanto a exposição a 0. 1 mg/L de midazolam induziu um significativo aumento na atividade dessa enzima (39. 9%) quando comparado ao grupo controle. O padrão de expressão gênica demonstrou que os níveis 7 de transcritos do CD73 apresentaram-se reduzidos (41,7%) após o tratamento com 0. 5 mg/L de midazolam. Com relação a sinalização colinérgica, diazepam diminuiu a hidrólise da ACh na concentração de 1. 25 mg/L (30. 7%) quando comparado ao grupo controle. Similarmente, a exposição à concentração de 0. 5 mg/L de midazolam também alterou a atividade enzimática da AChE, promovendo um aumento na hidrólise da ACh (36. 7%). É possível sugerir que essas drogas podem induzir um efeito direto na atividade enzimática, uma vez que foi observada uma diminuição na hidrólise de nucleotídeos e nucleosídeos após a exposição in vitro. Além disso, as alterações na hidrólise do AMP e atividade da ADA e da AChE sugerem uma modulação dos níveis extracelulares de adenosina e acetilcolina induzidos pela exposição aos fármacos benzodiazepínicos.

ADAR (Adenosine Deaminases acting on RNA) family proteins are double-strand RNA binding proteins that deaminate specific adenosines into inosines. This A-to-I conversion is called A-to-I RNA editing and is well conserved in the animal kingdom from nematodes to humans. RNA editing is a pre-splicing event on nascent RNA that may affect alternative splicing when the editing occurs in the exon-intron junction or in the intron. Also, editing may change biological function of small RNAs by editing the premicroRNAs or other noncoding RNAs. Editing also alters protein amino acid sequences because inosine in the mRNA base pairs with cytosine and is therefore read as guanosine. In mammals, there are three ADAR family proteins, ADAR1, ADAR2, and ADAR3, encoded by three different genes. So far, no enzymatic activity of ADAR3 is detected. The most frequently edited targets of ADAR1 and ADAR2 are regions covering copies of Alu transposable elements in primates. In addition, loss of some specific editing events leads to profound phenotypes when the editing does not occur correctly. For example, some human neural disorders – such as epilepsy, forebrain ischemia, and Amyotrophic Lateral Sclerosis – are known to be associated with abnormally edited ion channel transcripts. Drosophila has a single ADAR protein (encoded by the Adar gene) that is highly conserved with human ADAR2 (encoded by the ADARB1 gene). To date, 972 editing sites have been identified in 597 transcripts in Drosophila, and approximately 20% of AGO2-associated esiRNAs are edited. Similar to mammals, many ion channel-encoding mRNA transcripts undergo ADAR-mediated A-to-I editing in Drosophila. While Adar1 null mice die at the embryonic stage and Adar2 null mice die shortly after birth due to seizures, Adar null flies are morphologically normal and have normal life span under ideal conditions. However, Adar null flies exhibit severe neurodegeneration and locomotion defects from eclosion, whilst Adar overexpression (OE) is lethal. To better understand the physiological role of RNA editing and ADAR, and to shed light on ADAR-related human disease, I used Drosophila Adar mutant flies as a model organism to investigate phenotypes, and to find chromosomal deletions and specific mutations that rescue the neural-behavioural phenotype of the Adar null mutant flies. Using the publicly available chromosomal deletions collectively covering more than 80% of the euchromatic genome of Chromsome III, I performed a genetic screen to find rescuers of the lethality caused by Adar overexpression. I confirmed that mutation in Rdl (Resistant to dieldrin, the gene encoding GABAA receptor main subunit) rescues. This rescue was not likely caused by effects on Adar expression level or activity. Driven by the hypothesis that the rescue may be due to reduction in GABAergic input to neurons, I recorded spontaneous firing activity of Drosophila larval aCC motor neurons using in vivo extracellular current recording technique. As expected, the neurons overexpressing Adar had much less activities compared with wild type neurons. Also, I found that Adar null fly neurons fired much more and showed epilepsy-like increased excitability. Although feeding PTX (Picrotoxin), a GABAA receptor antagonist, failed to rescue the lethality, reducing the expression of GAD1 to reduce synthesis of GABA was able to rescue the ADAR overexpression lethality. These results suggest that ADAR may finetune neuron activity synergistically with the GABAergic inhibitory signal pathway. I used MARCM (mosaic analysis using a repressible cell marker) to detect cellautonomous phenotypes in Adar null cells in otherwise wild type flies. Although neurodegeneration, observed as enlarged vacuoles formation in neurophils, was detected both in histological staining and EM images, the Adar null neurons marked with GFP from early developmental stages were not lost with age. Nevertheless, swelling in the axons or fragmentation of the axon branches of Adar null neurons was sometimes observed in the midbrain. By comparing the Poly-A RNA sequencing data from Adar null and wild type fly heads, we detected significant upregulation of innate immune genes. I confirmed this by qRT PCR and found that inactive ADAR reduces the innate immune gene transcript levels almost as much as active ADAR does. Further, using the locomotion assay, I confirmed that reintroducing inactive ADAR into Adar null flies can improve the flies’ climbing ability. Based on the Adar null flies having comparatively low viability, I performed a second deficiency screen to find rescuers of Adar null low viability using the same set of deficiencies as in the lethality rescue screen described above. I found seven deletions removing 1 to 37 genes that significantly increased the relative viability of the Adar null flies. However, not all the rescuing deficiencies also improved the Adar null locomotion. One rescuing gene, CG11357 was mapped from one of the rescuing deficiencies, and some mutant alleles of cry, JIL-1 and Gem3 also showed significant effects on the Adar null fly viability. The single gene viability rescuers were also not necessarily locomotion or neurodegeneration rescuers. Although the initial aim was to find neural-behavioural rescuing genes from the viability screen, the viability rescuers found in the screen are more likely to play a role in different aspects of stress response for survival.

O zebrafish é um modelo experimental consolidado em diversas áreas, tais como genética e neurociências. Estudos têm demonstrado que muitos genes deste peixe são evolutivamente conservados e similares aos de mamíferos, incluindo a espécie humana. Com relação ao sistema purinérgico, já foi demonstrado que o zebrafish apresenta diferentes membros da família das NTPDases (nucleosídeo trifosfato difosfoidrolases) e uma ecto-5’-nucleotidase, capazes de clivar o ATP até adenosina, que atua através de purinoreceptores P1. A adenosina deaminase (ADA) é responsável pela clivagem da adenosina à inosina. Dois membros da família da ADA, conhecidos como ADA1 e ADA2, foram descritos e evidências recentes demonstraram a existência de um outro grupo similar de proteína, denominado ADAL (adenosina deaminase “like”). Portanto, no primeiro capítulo desta Dissertação, foram identificados distintos genes relacionados à ADA (ADA1, ADAL e dois genes ortólogos da ADA2) através de uma análise filogenética. Primers específicos para cada membro da ADA foram desenhados, experimentos otimizados de RT-PCR foram conduzidos e a quantidade relativa de transcritos determinada em diversos tecidos. Os resultados demonstraram que os genes da ADA1, ADAL, ADA2-1 e ADA2-2 podem ser diferentemente expressos nos tecidos de zebrafish. Além disso, a estratégia adotada também permitiu a identificação de uma isoforma truncada de ADA2-1 de splicing alternativo (ADA2-1/T), a qual foi expressa em diferentes intensidades nos tecidos analisados. Considerando que distintos membros da adenosina deaminase foram identificados, o segundo capítulo teve por objetivo caracterizar a atividade de desaminação de adenosina em frações solúvel e de membrana do cérebro de zebrafish. A atividade enzimática foi determinada pelo ensaio colorimétrico da amônia liberada. Foi verificado que em ambas as frações celulares estudadas a atividade de desaminação da adenosina foi linear quando utilizada uma concentração final de substrato de 1,5 mM. A curva de proteína, após incubação a 37ºC por 75 min (pH 7,0) e 120 min (pH 5,0) para as frações solúvel e de membrana, respectivamente, foi linear quando utilizada uma quantidade de proteína na faixa de 5–20 μg. A adição de 5 mM de Zn2+ promoveu uma queda significativa na desaminação de adenosina em membranas, a qual foi prevenida com 5 mM de EDTA. Utilizando adenosina como substrato, o KM aparente para ambas as frações celulares foi de aproximadamente 0,2 mM, enquanto que o Vmax foi de 12,3 + 0,73 e 17,5 + 0,51 (média + EP) nmol NH3.min-1.mg-1 de proteína para as frações solúvel e de membrana, respectivamente. Os resultados também demonstraram uma preferência para a desaminação de nucleosídeos da adenina em relação aos da guanina. Além disso, a incubação com 0,1 mM de EHNA (hidrocloreto de eritro-9-(2-hidróxi-3-nonil) adenina), um inibidor clássico da ADA1, promoveu uma inibição significativa da atividade enzimática em ambas as frações celulares. Estes achados sugerem que a existência de diferentes genes associados à ADA, bem como seus distintos padrões de expressão podem contribuir para a atividade de desaminação de adenosina em zebrafish.
Zebrafish (Danio rerio) is a consolidated experimental model in several areas, such as genetics and neuroscience. Studies have shown that many genes of this fish are evolutionary conserved and that share similarities to mammals genes, including humans. In relation to the purinergic system, it was demonstrated that zebrafish presents distinct members of the NTPDase (nucleoside triphosphate diphosphohydrolase) family and an ecto- 5'-nucleotidase, able to cleave ATP to adenosine, which acts via P1 purinoreceptors. Adenosine deaminase (ADA) is responsible for cleaving the adenosine to inosine. Two members of ADA family, known as ADA1 and ADA2, were described and recent evidence demonstrated the existence of another similar protein group named ADAL (adenosine deaminase “like”). Therefore, in the first chapter of this Dissertation, distinct ADA-related genes were identified (ADA1, ADAL e two ADA2 orthologous genes) by a phylogenetic analysis. Specific primers for each ADA members were designed, optimized semi-quantitative RT-PCR experiments were conducted and the relative amount of transcripts was determined in several tissues. The results demonstrated that ADA1, ADAL, ADA2-1 e ADA2-2 genes may be expressed differently in zebrafish tissues. In addition, the strategy adopted also allowed the identification of a truncated alternative splice isoform of ADA2-1, which was expressed in the analyzed tissues with different intensities. Considering that distinct adenosine deaminase members were identified, the objective of the second chapter was to characterize the adenosine deaminase activity in soluble and membrane fractions of zebrafish brain. The enzyme activity was measured by the colorimetric assay from the ammonia released. It was verified that in both cellular fractions, the adenosine deaminase activity was linear when it was used a final substrate concentration of 1.5 mM. The protein curve was linear using an amount of 5–20 μg of protein in the incubation at 37ºC for 75 min (pH 7.0) and 120 min (pH 5.0) for soluble and membrane fractions, respectively. The addition of 5 mM Zn2+ promoted a significant decrease on adenosine deamination in membranes, which was prevented by 5 mM EDTA. Using adenosine as substrate, the apparent KM for both cellular fractions was around of 0.2 mM, whereas the calculated Vmax were 12.3 + 0.73 and 17.5 + 0.51 (mean + SEM) nmol NH3.min-1.mg-1 of protein for the soluble and membrane fractions, respectively. The results also demonstrated a preference for the deamination of adenine nucleosides in relation to guanine derivates. In addition, the incubation with 0.1 mM EHNA (erythro-9-(2- hydroxy-3-nonyl)-adenine, a classical inhibitor of ADA1, promoted a significant inhibition on the enzyme activity in both cellular fractions. These findings suggest that the existence of different ADA-related genes and their distinct expression patterns may contribute for the adenosine deamination activity in zebrafish.