Dissertations / Theses on the topic 'Gene frequency'

With the development of nuclear transfer from somatic cells in several species, gene targeting can now be utilised for the design of more accurate animal models for human diseases and the generation of genetically modified livestock. However, its use is limited by the low frequency of homologous recombination in somatic cells. Future applications of gene targeting, such as the development of human gene therapies, will also require dramatic improvements in the efficiency of homologus recombination. The aim of this work has been devise strategies for the stimulation of gene targeting efficiency <i>in vitro.</i> Using a very sensitive test system based on the directly selectable knockout of the <i>HPRT</i> gene in ES cells <i>in vitro,</i> a variety of experimental approaches were assessed for their ability to enhance effective targeting frequency - measured as the ratio of homologous to total integrants. These can be grouped into three main subcategories: (1) Modifications of the targeting vector (nuclear localisation signals, dsRNA vectors); (2) Alteration of the target conditions (methylation status, chromatin configuration); and (3) Manipulation of the expression of recombination-related genes (down-regulation of homologous recombination repressors and overexpression of recombinases). Loss of p53, Ku80 or DNA-PK_cs function did not result in enhanced targeting efficiency in ES cells. In contrast, constitutive overexpression of the eukaryotic recombinase Rad51 yielded a 4-fold increase in effective targeting frequency compared to wild-type control cells. Significant increases were also observed in <i>Dnmt1-/-</i> and poly(ADP-rybosyl)polymerase (PARP) -defective cells, as well as in cells treated with chemical inhibitors of PARP activity. These results contribute to the knowledge of the mechanisms underlying homologous recombination in mammalian cells, and suggest possible avenues of research to overcome the practical limitations of gene targeting.

Gene transcription in individual living cells is inevitably a stochastic and dynamic process. Little is known about how cells and organisms learn to balance the fidelity of transcriptional control and the stochasticity of transcription dynamics. In an effort to elucidate the contribution of environmental signals to this intricate balance, a Three State Model was recently proposed, and the transcription system was assumed to transit among three different functional states randomly. In this work, we employ this model to demonstrate how the stochastic dynamics of gene transcription can be characterized by the three transition parameters. We compute the probability distribution of a zero transcript event and its conjugate, the distribution of the time durations in gene on or gene off periods, the transition frequency between system states, and the transcriptional bursting frequency. We also exemplify the mathematical results by the experimental data on prokaryotic and eukaryotic transcription. The analysis reveals that no promoters will be definitely turned on to transcribe within a finite time period, no matter how strong the induction signals are applied, and how abundant the activators are available. Although stronger extrinsic signals could enhance promoter activation rate, the promoter creates an intrinsic ceiling that no signals could cross over in a finite time. Consequently, among a large population of isogenic cells, only a portion of the cells, but not the whole population, could be induced by environmental signals to express a particular gene within a finite time period. We prove that the gene on duration follows an exponential distribution, and the gene off intervals show a local maximum that is best described by assuming two sequential exponential process. The transition frequencies are determined by a system of stochastic differential equations, or equivalently, an iterative scheme of integral operators. We prove that for each positive integer n , there associates a unique time, called the peak instant, at which the nth transcript synthesis cycle since time zero proceeds most likely. These moments constitute a time series preserving the nature order of n.

Members of the HSAG family of mammalian genomic elements were subcloned into the pSV2-DHFR expression vector and shown to encourage vector amplification in cis when transfected into a variety of cell lines. The interaction of multiple positive acting elements was required for this effect, with the native configuration of these elements in HSAG-1 producing the greatest effect. These positive acting elements; purine-pyrimidine tracts, Alu-like repetitive elements, stem-loop structures, and A+T rich sequences, have been previously associated with "hotspots" for recombination. Analysis of the structure of amplified vector sequences in MTX resistant pSV2-DHFR-HSAG-1 transfectants showed that these cells possessed a greater number of novel-joints indicating that HSAG elements may stimulate local recombination. Other experiments demonstrating an interaction between vector and HSAG sequences support this conclusion. We suggest that the stimulation of local recombination events by HSAG elements during vector amplification produces novel joints which then encourage further amplification.

Methylmalonic aciduria results from defects in the enzyme methylmalonyl-CoA mutase and from defects in the synthesis of the enzyme's cofactor adenosylcobalamin. Two patients who excrete methylmalonic acid have been shown to have a homozygous nonsense mutation in the methylmalonyl-CoA epimerase gene (MCEE). To further understand the causes of methylmalonic acid excretion, the MCEE gene was sequenced in 229 patients who excreted methylmalonic acid for which no cause was known. Mutations were detected in five patients. Fusion of fibroblast lines from two patients with a homozygous nonsense mutation in MCEE did not result in correction of [14C]propionate incorporation toward control values while the defect in these fibroblasts was complemented by mut, cblA, and cblB fibroblasts. Transfection with wild-type MCEE cDNA resulted in correction of the biochemical phenotype in cells from both patients. These experiments support the hypothesis that a defective epimerase enzyme can be a cause of elevated methylmalonic acid excretion.

Frequency-dependent selection has long been a popular heuristic explanation for the maintenance of genetic diversity in natural populations. Indeed, a large body of theoretical and empirical work has already gone into elucidating the causes and consequences of frequency-dependent selection. Most theoretical work, to date, has focused either on the diallelic case, or dealt with only very specific forms of frequency-dependence. A general model of the maintenance of multiallelic genetic diversity has been lacking. Here we extend a flexible general model of frequency-dependent selection, the pairwise interaction model, to the case of multiple alleles. First, we investigate the potential for genetic variation under the pairwise interaction model using a parameter-space approach. This approach involves taking a large random sample of all possible fitness sets and initial allele-frequency vectors of the model, iterating each to equilibrium from each set of random initial conditions, and measuring how often variation is maintained, and by which parameter combinations. We find that frequency- dependent selection maintains full polymorphism more often than classic constant-selection models and produces more skewed equilibrium allele frequencies. Fitness sets with some degree of rare advantage maintained full polymorphism most often, but a variety of non-obvious fitness patterns were also found to have positive potential for polymorphism. Second, we further investigate some unusual dynamics uncovered by the parameter-space approach above. Long-period allele-frequency cycles and a small number of aperiodic trajectories were detected. We measured the number, length and domains of attraction of the various attractors produced by the model. The genetic cycles produced by the model did not have periods short enough to be observable on an ecological time scale. In a real world system, allele-frequency cycling is likely to be indistinguishable from stable equilibrium when observed over short time scales. Third, we use a construction approach to model frequency-dependent selection with mutation under the pairwise interaction model. This approach involves the construction of an allelic polymorphism by bombarding an initial monomorphism with mutant alleles over many generations. We find that frequency-dependent selection is able to generate large numbers of alleles at a single locus. The construction process generates a wide range of allele- frequency distributions and genotypic fitness relationships. We find that constructed polymorphisms remain permanently invasible to new mutants. Analysis of constructed fitness sets may even reveal a signature of positive frequency dependence. Finally, we examine the numbers and distributions of fitnesses and alleles produced by construction under the pairwise interaction model with mutation from existing alleles, using several different methods of generating mutant fitnesses. We find that, relative to more general construction models, generating mutants from existing alleles lowers the average number of alleles maintained by frequency-dependent selection. Nevertheless, while the overall numbers of alleles are lower, the polymorphisms produced are more stable, with more natural allele-frequency distributions. Overall, frequency-dependent selection remains a powerful mechanism for the maintenance of genetic variation, although it does not always work in intuitively obvious ways.

Orientadores: Claudio Saddy Rodrigues Coy, Carmen Silvia Passos Lima<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas<br>Made available in DSpace on 2018-08-20T01:34:06Z (GMT). No. of bitstreams: 1 Credidio_Laura_M.pdf: 7330672 bytes, checksum: 03e0aafb86a0b4df9c88c89f064490e2 (MD5) Previous issue date: 2012<br>Resumo: O papel da angiogênese para o desenvolvimento do câncer colorretal (CCR) ainda não é totalmente conhecido. Uma das principais glicoproteínas responsáveis pela angiogênese é o fator de crescimento endotelial vascular (VEGF), acredita-se que o polimorfismo C936T, localizado no gene VEGF, esteja correlacionado com a suscetibilidade para o desenvolvimento do CCR. Objetivos: Identificar as freqüências dos genótipos do polimorfismo C936T do gene VEGF em pacientes portadores de adenocarcinoma colorretal esporádico (ACE) e controles e correlacionar a ocorrência do mesmo com as seguintes variáveis: sexo, idade, localização tumoral, acometimento de linfonodos (N) e infiltração tumoral (T) em pacientes. Material e método: No período compreendido entre outubro de 2008 a dezembro de 2009 foram coletadas amostras de sangue periférico de pacientes com ACE, no ambulatório de Coloproctologia do HC UNICAMP (G1). O grupo controle (G2) foi constituído por doadores de sangue. Foram excluídos do estudo portadores de polipose familiar, síndrome de Lynch, doenças inflamatórias intestinais e com antecedente familiar de CCR. A extração do DNA genômico se deu por cloreto de lítio e por kit de extração de DNA. Os genótipos do polimorfismo C936T foi avaliado por meio da reação em cadeia da polimerase e digestão enzimática. Resultados : O G1 constou de 261 pacientes, sendo 52,1% do sexo masculino com média de idade de 64,9 (32-97) anos. O G2 foi formado por 261 doadores de sangue, com idade media de 52,9 anos (25-62) sendo 52,1% do sexo masculino. A ocorrência do genótipo selvagem (CC) foi de 80,5%, do heterozigoto (CT) foi de 18,4% e do homozigoto (TT) de 1,1% em pacientes. No G2 a ocorrência dos genótipos foram 78,5% (CC), 20,7% (CT) e 0,8% (TT), indivíduos com genótipos distintos do gene estiveram sob riscos similares do ACE. Com relação á localização do tumor, 51,5% encontravam-se no reto, 16,4% cólon direito, 31,1% em cólon esquerdo. Em relação ao grau de invasão tumoral, 0,7% foram classificados como Tis, 1,5% T0, 8,1% T1, 19,3% T2, 65,2% T3 e 7,4% como T4. Quanto ao acometimento de linfonodos, 53,9% foram classificados como N0, 33,6% como N1 e 12,5% como N2. Não se observou diferenças em relação ao grau de invasão tumoral, acometimento de linfonodos ou ocorrência de metástases (p = 0,2996) em relação à ocorrência do polimorfismo C936T. Conclusão: O polimorfismo C936T do gene VEGF não correlaciona-se com o risco de ocorrência do tumor e com o sexo, idade, localização da lesão, acometimento de linfonodos e infiltração tumoral<br>Abstract: Background: The role of angiogenesis for the development of Colorectal Cancer (CC) is not yet fully known. One of the major glycoprotein responsible for pro-angiogenesis is vascular endothelial growth factor (VEGF). It is believed that the C936T polymorphism located in the VEGF gene is correlated with less susceptibility to the development of CC. Objectives: To identify the genotype frequencies of the C936T polymorphism of the VEGF gene in patients with sporadic colorectal adenocarcinoma (ACE) and controls and to correlate the occurrence of the same with following variables: gender, age, tumor location, lymph node (N) and tumor infiltration (T). Methods: Between October 2008 and December 2009 samples were collected from peripheral blood of patients with colorectal cancer in the clinic of Coloproctology of HC UNICAMP (G1). The control group (G2) comprised blood donors. We excluded patients with familial polyposis, Lynch syndrome, inflammatory bowel diseases and family history of CC. The genomic DNA extraction was done by lithium chloride and by DNA extraction kit. The genotypes of the C936T polymorphism were assessed by polymerase chain reaction and enzymatic digestion. Results: G1 consisted of 261 patients, 52.1% male with a mean age of 64.9 (32-97) years. The G2 is composed of 261 blood donors, with a mean age of 52.9 years (25-62) 52.1% male. The occurrence of wild genotype (CC) was 80.5%, the heterozygous (CT) was 18.4% and the homozygous (TT) of 1.1% in patients. In G2 the occurrence of genotypes were 78.5% (CC), 20.7% (CT) and 0.8% (TT); individuals with different genotypes of the gene were under similar risks of ACE. Regarding the location of the tumor, 51.5% were in the rectum, right colon 16.4%, 31.1% in the left colon. Regarding the degree of tumor invasion, 0.7% was classified as Tis, T0 1.5%, 8.1% T1, 19.3% T2, T3 65.2% and 7.4% as T4. As for the involvement of lymph nodes, 53.9% were classified as N0, 33.6% N1 and 12.5% N2. There were no significant differences in the degree of tumor invasion, lymph nodes or occurrence of metastases (p = 0.2996) in relation to the occurrence of the C936T polymorphism. Conclusion: The C936T polymorphism of the VEGF gene did not correlate with the risk of tumor occurrence and sex, age, lesion location, lymph nodes and tumor infiltration<br>Mestrado<br>Ciências da Cirurgia<br>Mestre em Ciências

The experimental measurement of gene expression levels has produced preliminary results on the regulation, pathways and networks of genes in cells. Furthermore, the number of available three-dimensional folded structures of proteins increases on a daily basis. The ultimate aim of both genomics and proteomics froni the perspective of bioinformatics, is to map out all the circuits of energy and information processing in life by terms of molecular interactions in a system~tic way with minimal human intervention. In this thesis we propose a new rule mining framework for ill silico inference of protein-protein interactions and an effective class of techniques that identify domain-domain interactions from multiple domain protein structures. The above two approaches allow molecular biologists to use both gene expression data and three dimensional folded protein structures to efficiently predict or validate potential protein-protein interactions. A novel temporal rule mining technique is used to infer rules that relate local expression patterns across a set of genes. The set of these rules is associated to a set of potential interacting pairs of proteins. . I Probable protein-protein interactions can be validated against a network of protein domain interactions that are computed by considering interacting domains in known multiple domain protein structures. We introduce efficient algorithms that can effectively identify protein domain-domain interactions in multiple protein domain structures which are solved and publicly available. To analyse the vast amount of interactions between all the protein domains classified to superf~milies we propose a new graphtheoretic measure which is able to rank protein superfamilies by incorporating information about the topology of the whole network. To summarise, the work in this thesis consists of a new temporal rule mining framework applied .' to gene expression data analysis and furthermore, a novel class of algorithms that effectively identify ' domain-domain interactions from known protein structures.

Abnormal calcium salts depositing in the arterial vessels is considered to be a novel marker of atherosclerosis and related to cerebrovascular disease. Matrix gamma-carboxyglutamic acid protein (MGP) is one of the most potent inhibitors of ectopic mineralization, so it may be associated with calcification of atheromatous plaques, their instability and rupture, and thrombi formation. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/32195

Orientador: Hercílio Martelli Júnior<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-18T03:14:48Z (GMT). No. of bitstreams: 1 Aquino_SibeleNascimentode_M.pdf: 1254396 bytes, checksum: 23d834d1395b6d0cfe104c6231785589 (MD5) Previous issue date: 2011<br>Resumo: Fissuras do lábio e/ou palato (FL/P) representam uma das anomalias congênitas mais comuns em humanos. A etiologia das FL/PNS é complexa e envolve a participação de inúmeros genes e fatores ambientais. Diversos estudos têm investigado genes relacionados a síndromes, que apresentam FL/P em seu espectro clínico, e/ou que são expressos durante o desenvolvimento do lábio e/ou palato. O objetivo deste estudo foi verificar se novos polimorfismos contidos nos genes relacionados ao desenvolvimento do lábio e palato, incluindo TGF?3, MSX1, MYH9 e JAG2, podem contribuir para a etiologia das FL/PNS. Seis regiões polimórficas foram genotipadas por PCR-RFLP (reação em cadeia da polimerase associada à análise de polimorfismo de fragmentos de restrição enzimática) em amostras de DNA proveniente de 367 pacientes com FL/PNS (grupo caso) e de 413 indivíduos não afetados (grupo controle). No grupo caso, 54% foram do gênero masculino e 46% do feminino, com idade média de 19,1 ± 14,9 anos e prevalência de indivíduos feodermas (42,5%) e leucodermas (42%). As fissuras lábio-palatinas (FLP) foram predominantes (54%), seguidas pela fissura labial (FL) (24%) e fissura palatina (FP) (22%). Do total de seis polimorfismos analisados neste estudo, apenas um foi confirmado nessa população: rs1057744 do gene JAG2. Para este locus polimórfico, o alelo A e o genótipo GA foi mais comum, no grupo controle e caso, não sendo encontrada diferença estatística significante. Para esse polimorfismo, a análise em um modo dominante ou recessivo também não mostrou diferenças estatísticas significantes. Assim, demonstrou-se que os polimorfismos rs34019007 e rs4252315, do gene TGF?3, rs62636562, do gene MSX1, rs11549910 e rs11549909, do gene MYH9 não foram confirmados. O polimorfismo rs1057744 do gene JAG2, embora confirmado, não apresentou associação significante com FL/PNS na população avaliada<br>Abstract: Cleft lip and/or cleft palate (CL/P) is one of the most common congenital anomaly in humans. NSCL/P etiology is complex and involves the participation of numerous genes and environmental factors. Several studies have investigated genes related to syndromes that have CL/P in their clinical and/or which are expressed during the development of lip and palate. The aim of this study was to determine whether polymorphisms contained genes related to the development of lip and/or palate, including TGF?3, MSX1, MYH9 and JAG2 can contribute to the etiology of NSCL/P. Six polymorphic regions were genotyped by PCR-RFLP (restriction fragment length polymorphism-polymerase chain reaction) in DNA samples from 367 patients affected by NSCL/P (experimental group) and 413 clinically normal subjects (control group). In the affected group, 54% were male and 46% female, mean age 19.1 ± 14.9 years and the prevalence of mixed black individuals (42.5%) and Caucasian (42%). The clefts of the lip with or without cleft palate (CLP) were predominant (54%), followed by cleft lip (FL) (24%) and cleft palate FP (22%). Out of 6 probable polymorphisms, only one was confirmed in this population: rs1057744 gene JAG2. For this polymorphic locus, the A allele and the genotype was slightly more common in the contr ol and experimental, without statistically signific ant differences. For this polymorphism , the analysis in a dominant or recessive mode also showed no statistically significant difference s between the group. This study demonstrated that the polymorphisms rs34019007 and rs4252315, present in the gene TGF?3, rs62636562, in the MSX1 gene, rs11549910 and rs11549909, in the MYH9 gene we re not confirmed. The rs1057744 polymorphism in JAG2 gene was confirmed in this study but not significantly associated with NSCL/P in the Brazilian population<br>Mestrado<br>Patologia<br>Mestre em Estomatopatologia

Paraoxonase (PON) é uma família multigene de enzimas, a qual inclui PON1, PON2 e PON3. Investigações há mais de duas décadas vêm permitindo um melhor conhecimento da função dos genes da paraoxonase, em especial da PON1, no metabolismo de inseticidas organofosforados, lípides oxidados e medicamentos. O principal local de síntese da PON1 é o fígado, e no soro encontra-se mais comumentente associada à HDL-C. Exibe dois principais polimorfismos, posição 55 (L/M) e 192 (Q/R) que estão relacionados ao nível sérico e atividade enzimática respectivamente. A freqüência dos alelos do gene PON1 apresenta considerável variabilidade entre diferentes populações. São escassos os estudos sobre a PON2, porém sabe-se que é expressa em vários tecidos, sugerindo, dessa forma, que essa enzima tenha uma ação localizada (intracelular). Dois polimorfismos são os mais estudados no gene PON2, posições 148 (A/G) e 311 (C/S) e têm sido associados à numerosas condições fisiopatológicas como variações no metabolismo e níveis plasmáticos de lipoproteínas e glicose. Este trabalho tem por objetivos caracterizar as freqüências das mutações 192 (Q/R) e 55(L/M) no gene da PON1 e 311(C/S) e 148(A/G) no gene da PON2, bem como analisar a atividade das isoformas da enzima PON1 em uma população brasileira, da cidade de São Paulo, de diferentes origens étnicas. O estudo foi realizado entre 2005 e 2006 com 179 doadores de sangue, classificados etnicamente. Foi coletado sangue para extração do DNA genômico, para posterior determinação dos polimorfismos, através da técnica de PCR e soro para a determinação da atividade basal sérica da enzima paraoxonase. Os genótipos LL (46,4%) e LM (45,2%) na posição 55 (L55M) e QR (49,2%) na posição 192 (Q192R) do gene PON1 são os mais freqüentes na população total. Entre os doadores brancos, os genótipos mais freqüentes foram LM (51,9%) posição 55 e QR (45,6%) na posição 192. No caso dos doadores mulatos, LL (50,0%) e QR (52,8%) são os genótipos mais observados e para os doadores negros, os genótipos LL (69,7%) e QR (50,0%) nas posições 55 e 192 respectivamente. O alelo L é o mais freqüente nos três grupos étnicos, no entanto, em relação a freqüência alélica do polimorfismo da posição 192, o alelo Q predomina entre brancos e mulatos, já para os negros o alelo R é mais freqüente. No gene PON2, os genótipos mais freqüentes na população são AA (54,2%) na posição 148 (A148G) e CS (52,5%) na posição 311 (C311S). Quando comparadas as freqüências genotípicas do gene PON2 no polimorfismo da posição 148 (A/G) entre os três grupos étnicos, o genótipo AA foi o mais freqüente, em brancos (60,7%), mulatos (50,0%) e em negros (46,4%). Já para o polimorfismo da posição 311 (C/S), os doadores brancos têm o genótipo CS (46,8%) e SS (46,8%) como o de maior freqüência e nos doadores mulatos e negros o genótipo mais freqüente é CS com 56,9% e 57,1% respectivamente. Não houve diferença na distribuição alélica dos três grupos étnicos, sendo os alelos A e S os mais freqüentes. Em relação à atividade da enzima, as isoformas resultantes dos genótipos LL (posição 55) e RR (posição 192) apresentaram os valores das medianas significantemente maiores que as demais isoformas, sendo mais eficazes na hidrólise do paraoxon.<br>Paraoxonase (PON) is a multigene family of enzymes that include PON1, PON2 and PON3. Investigations at more than two decade coming to allow the best understanding of the function of the paraoxonase genes, in special of the PON1 in the metabolism organophosphate insecticides, oxidized lipids and drugs. The main place of PON1 synthesis is the liver, and in the serum is currently associated to HDL-C. Show two main polymorphisms, in the position 55 (L/M) and 192 (Q/R) that are relation with serum level and enzymatic activities, respectively. The allele frequency of PON1 genes shows variability in different populations. There is a few studies about PON2, but it is known that is expressed in many tissues, suggesting, the enzyme have a local action (intracellular). Two polymorphisms are the most studied in the PON2 gene, 148 (A/G) and 311 (C/S) positions and they have been associated to a lot of physiologic conditions like metabolisms chances and lipoprotein and glucose plasma level. This work have the objective to characterizer the frequency of 192 (Q/R) and 55 (L/M) mutation in the PON1 gene and 311 (C/S) e 148 (A/G) mutations in the PON2 gene as well as to analyze the enzyme PON isoform activity in the brazilian population of São Paulo City, in different ethnics groups. The study was realized during 2005 to 2006 in 179 blood donor classificated according to the ethnics. It was colleted the blood to DNA genomic extraction after to polymorphisms determination was utilized the PCR technique and the serum to determine the paraoxonase enzyme basal activity. The genotypes LL (46,4%) and LM (45,2%) in the 55 (L55M) positions and QR (49,2%) in the 192 (Q192R) position in the PON1 gene are the most frequently in the total population. Among the white donor, the genotypes most frequently were LM (51,9%) in the 55 position and QR (45,6%) in the 192 position. In mulatoes, LL (50,0%) and QR (52,8%) are the most observed genotypes and black donor, the genotypes LL (69,7%) and QR (50,0%) in the 55 and 192 positions, respectively. The L allele is the most frequently in the three ethnics groups, however, the relation of polymorphism allelic frequency in the position 192, the Q allele to predominate among mutates, and to the negroes the allele R is the most frequency. In the PON 2 gene, the most frequently genotypes are AA (54,2%) in the 148 (A148G) position and CS (52,5%) in the 311 (C311S) position. When they are compared with PON2 genotypes frequency in the polymorphisms of 148 (A/G) position among three etnics groups AA was the most frequently, in the white (60,7%), mulatoes (50,0%) and negroes (46,4%). To the polymorphisms at 311 (C/S) positions is the most frequently in white donors have a genotype CS (46,8%) and SS (46, 8%) and in the mulatoes and negroes donors the most frequency genotypes is CS with 56,9% and 57,1% respectively. There aren?t differences in the allelic distribution in the three ethnics groups, the A and S allelic are the most frequently. In relation to enzyme activity, the product of isoform to LL (55 position) and RR (192 position) genotypes to present the median level are significantly more than another isoforms, they are more efficient in the paraoxon hydrolyzes

Background: The limited within-breed genetic heterogeneity and an enrichment of disease-predisposing alleles have made the dog a very suitable model for the identification of genes associated with risk for specific diseases. Canine mammary cancer is an example of such a disease. However, the underlying inherited risk factors for canine mammary tumours (CMTs) are still largely unknown. In this study, 52 single nucleotide polymorphisms (SNPs) in ten human cancer-associated genes were genotyped in two different datasets in order to identify genes/alleles associated with the development of CMTs. The first dataset consisted of English Springer Spaniel (ESS) CMT cases and controls. ESS is a dog breed known to be at increased risk of developing CMTs. In the second dataset, dogs from breeds known to have a high frequency of CMTs were compared to dogs from breeds with a lower occurrence of these tumours. Results: We found significant associations to CMT for SNPs and haplotypes in the estrogen receptor 1 (ESR1) gene in the ESS material (best P-Bonf = 0.021). A large number of SNPs, among them several SNPs in ESR1, showed significantly different allele frequencies between the high and low risk breed groups (best P-Bonf = 8.8E-32, best P-BPerm = 0.076). Conclusions: The identification of CMT-associated SNPs in ESR1 in two independent datasets suggests that this gene might be involved in CMT development. These findings also support that CMT may serve as a good model for human breast cancer research.

Introduction. Atrial fibrillation is a heart rhythm disorder, characterized by rapid and uncoordinated atrial activation which is the most common arrhythmia in clinical practice. Atrial fibrillation is observed in 1.5 - 2% of the general population and its incidence increases with age reaching more than 8-15% by 80 years of age. Atrial fibrillation is traditionally considered as a non genetic disorder. The cause of atrial fibrillation in 10-20% of cases is unknown and it is diagnosed as idiopathic.

The advent of high-throughput sequencing has brought about the creation of an unprecedented amount of research data. Analytical methodology has not been able to keep pace with the plethora of data being produced. Two assays, ImmunoSEQ and the cytokinesisblock micronucleus (CBMN), that both produce count data and have few methods available to analyze them are considered. ImmunoSEQ is a sequencing assay that measures the beta T-cell receptor (TCR) repertoire. The ImmunoSEQ assay was used to describe the TCR repertoires of patients that have undergone hematopoietic stem cell transplantation (HSCT). Several different methods for spectratype analysis were extended to the TCR sequencing setting then applied to these data to demonstrate different ways the data set can be analyzed. The different methods include CDR3 distribution perturbation, Oligoscores, Simpson's diversity, Shannon diversity, Kullback-Liebler divergence, a non-parametric method and a proportion logit transformation method. Herein we also demonstrate adapting compositional data analysis methods to the TCR sequencing setting. The various methods were compared when analyzing a set of 13 subjects who underwent hematopoietic stem cell transplantation. The eight subjects who developed graft versus host disease were compared to the five who did not. There was no little overlap in the results of the different methods showing that researchers must choose the appropriate method for their research question of interest. The CBMN assay measures the rate of micronuclei (MN) formation in a sample of cells and can be paired with gene expression or methylation assays to determine association between MN formation and other genetic markers. Herein we extended the generalized monotone incremental forward stagewise (GMIFS) method to the situation where the response is count data and there are more independent variables than there are samples. Our Poisson GMIFS method was compared to a popular alternative, glmpath, by using simulations and applying both to real data. Simulations showed that both methods perform similarly in accurately choosing truly significant variables. However, glmpath appears to overfit compared to our GMIFS method. Finally, when both methods were applied to two data sets GMIFS appeared to be more stable than glmpath.

A paraoxonase sérica humana (PON) vem sendo amplamente estudada. Além da capacidade de PON1 em hidrolisar compostos organofosfatados, sabe-se, atualmente, que toda a família PON (composta por PON1, PON2 e PON3) promove a proteção de lípides, incluindo-se a lipoproteína de baixa densidade (LDL) contra a oxidação. O gene da PON1 sérica apresenta dois sítios polimórficos bem determinados: a troca Gln192Arg (Q/R) e Met55Leu, os quais estão associados com diferenças na atividade e concentrações séricas da enzima, respectivamente. Também o polimorfismo Cys311Ser parece contribuir sinergisticamente com o alelo PON1-192R quanto ao risco cardiovascular em algumas populações. Já foi demonstrado, por sua vez, que pacientes infectados pelo vírus HIV podem desenvolver dislipidemia e que tanto a atividade como a concentração de PON1 podem ser influenciadas por esta infecção. O objetivo deste estudo foi determinar as freqüências alélicas dos polimorfismos genéticos PON1-192QR, PON1-55LM, PON2-311SC e PON2-148AG, bem como avaliar a atividade de PON1 e a peroxidação lipídica no plasma de indivíduos portadores de HIV. Materiais e Métodos após aprovação pela comissão de ética e da aplicação do termo de consentimento pós-esclarecido, 350 (264 homens e 86 mulheres) pacientes infectados pelo HIV foram incluídos no estudo. Foi avaliado ainda um grupo de 32 (23 homens e 9 mulheres) indivíduos recentemente diagnosticados como portadores do vírus. Uma população saudável composta por 179 doadores de sangue, todos de sexo masculino, foi avaliada como controle. Após a extração do DNA, procedeu-se à genotipagem para os polimorfismos de PON1 e PON2 através de PCR-RFLP. A atividade paraoxonase de PON1 foi avaliada por espectrofotometria empregando-se paraoxon como substrato. O colesterol total, VLDL-colesterol, HDL-colesterol e triglicérides foram determinados por métodos padrão. A fração LDL-colesterol foi calculada pela fórmula de Friedwald. Resultados As freqüências alélicas para os polimorfimos de PON1 nos pacientes foram: 36,43% para o alelo PON1-192R, 57,86% para PON1-55L, 65,57% para PON2-311S e 76,43% para o alelo PON2-148A. No grupo de indivíduos recentemente diagnosticados como portadores de HIV estas freqüências foram 37,50%, 51,56%, 81,25% e 68,75, respectivamente. No grupo composto pelos saudáveis, a freqüência alélica de PON1-192R foi 43,02%, a de PON1-55L foi 68,99%, a do alelo PON2-311S foi 67,60% e, por fim, a freqüência do alelo PON2-148A foi 75,14%. Conclusões As distribuições alélicas dos polimorfimos em PON1 e PON2 foram similares dentre os portadores de HIV e os controles. A relação entre os genótipos PON1-192QR e/ou PON1-55LM e a atividade de PON1 em pacientes não diferiu daquela observada nos controles. Observou-se ainda, aumento do colesterol, dos triglicérides e da peroxidação lipídica no plasma dos infectados pelo vírus e, nos pacientes, uma maior atividade enzimática dentre os possuidores de contagem de linfócitos CD4+ acima de 500 células por mm3.<br>Human serum paraoxonase (PON) has been the subject of a number of studies. Beside the capacity of PON1 in hydrolyzing organophosphate compounds, it is known now that the entire PON family (which comprises PON1, PON2 and PON3) protects lipids, including low-density lipoprotein (LDL), from oxidation. Serum PON1 gene presents two well-determined genetic polymorphic sites: a Gln192 Arg (Q/R) and Met55 Leu, which are associated with differences in enzymatic activity and serum concentrations, respectively. Moreover, PON2 Cys311 Ser polymorphism seems to contribute synergistically with PON-192R allele to cardiovascular risk in some populations. It has been shown that HIV infected patients may develop dyslipidemia and that PON1 activity and concentration may be influenced by this infection. The aim of this study was to determine allelic frequencies of PON1-192QR, PON1-55LM, PON2-311SC and PON2-148AG genetic polymorphisms, evaluate PON1 activity and lipid peroxidation in plasma of HIV patients. Methods and Subjects after ethical committee approval and written consent, 350 (264 men and 86 women) HIV infected patients were included in the study. It was also evaluated a group of 32 recently diagnosed HIV individuals (23 men and 9 women). As controls, a healthy population formed by 179 men, blood donors, was studied. After DNA extraction PON1 and PON2 genotyping were performed by PCR-RFLP. Paraoxonase activity of PON1 was evaluated spectrofotometrically using paraoxon as substrate. Serum cholesterol, VLDL-cholesterol, HDL-cholesterol and triglycerides were analyzed by standard methods. LDL-cholesterol was calculated by Friedewald formula. Results: Allelic frequencies for PON1 polymorphisms in patients were: 36,43% for PON1-192R, 57,86% for PON1-55L, 65,57% for PON2-311S and 76,43% for PON2-148A. In recently diagnosed individuals these frequencies were 37,50%, 51,56%, 81,25% and 68,75% respectively. In controls, PON1-192R allelic frequency was 43,02%, PON1-55L was 68,99%, PON2-311S was 67,60% and PON2-148A was 75,14%. Conclusion: Allelic distributions of PON1 and PON2 polymorphisms were similar in HIV patients and controls. The relationship between PON1-192 QR and/or PON1-55LM genotypes and enzyme activity in patients were not different from controls. It was also observed an elevation of cholesterol, tryglicerides and lipid peroxidation levels in plasma of infected patients and, in this group, a higher activity in those which CD4+ cells counting was more than 500 cell/mm3.

I here explore the dual roles of gene flow in determining evolutionary and demographic processes in the Misty Lake threespine stickleback (Gasterosteus aculeatus L.). In the Misty watershed, the lake fish have streamlined bodies and numerous gill rakers whereas the inlet stream fish have deeper bodies and reduced number of gill rakers, differences that are adaptive for lake and stream environments respectively. The outlet stream population, however, is morphologically intermediate between the lake and inlet populations as a result of high gene flow from the lake preventing adaptation to the stream environment. First, I quantify the constraining effect of gene flow on adaptive divergence in the Misty outlet using two complementary approaches. By comparing phenotypic values and environmental differences between the three habitats (i.e. lake, inlet and outlet), I estimate that the constraint imposed by gene flow on phenotypic divergence is in the order of 80%, i.e. the outlet population only achieves 20% of the phenotypic divergence expected in the absence of gene flow. Parameterization of a quantitative genetic model confirms this value is possible given a biologically realistic range of parameter values. Second, I demonstrate that this constraint imposed by gene flow on adaptation likely contributes to an observed reduction in abundances along the outlet stream. I do so using a transplant experiment and a three-year selection experiment. Quantification of the amount of dispersal suggests that the negative influence of gene flow offsets the positive demographic influence of the immigration of individuals. In summary, gene flow has profound consequences for both evolutionary and demographic processes taking place in the Misty system.

Magister Public Health - MPH<br>Aim: To determine and compare the prevalence of CCR5-Δ32 and CCRV64I genes in HIV positive and HIV negative population of pregnant women from Harare, in Zimbabwe. Results: The proportion of pregnant women with the homozygous CCR2V64I gene was 24.38% and this gene was two times more associated with HIV infection than in those without it ( RR= 2.32, 95% CI-1.38-3.92). No CCR5-Δ32 deletion was detected in the studied population. Conclusion: The homozygous CCR2V64I gene and STIs were more prevalent in HIV infected pregnant women than in uninfected pregnant women and no homozygousCCR5-Δ32 gene was detected in this study.<br>South Africa

Made available in DSpace on 2016-08-19T18:16:00Z (GMT). No. of bitstreams: 1 FABIO FRANCA SILVA.pdf: 387985 bytes, checksum: b614ae131f06a658fbdac4196b4d623c (MD5) Previous issue date: 2009-04-06<br>FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTIFICO E TECNOLÓGICO DO MARANHÃO<br>Recurrent spontaneous abortion (RSA) is defined as two or more consecutive spontaneous pregnancy losses before the 20th week of gestation, a situation that occurs in 1 to 2% of women in reproductive age. Genetic, anatomical, endocrine, infectious and immunologic factors through mechanisms that relate to the Major Histocompatibility Complex (MHC) and the presence of certain HLA (Human Leukocyte Antigens) are associated to RSA. HLA gene is located on the short arm of chromosome 6 between the 6p21.31 and 6p21.33 regions. This gene is inherited in haplotypes and expressed in codominance, having influence on modulation and induction of mother tolerance during the pregnancy. The aim of this study was to compare the allelic frequencies of HLA-A*, HLA-B* and HLA-DRB1* loci in women with and without RSA. It was a case-control study in 200 women (100 for each group) between 18 and 35 years of age. All samples were typified by the PCR-SSOP method (Polymerase Chain Reaction-Sequence Specific Oligonucleotide Probes). The most frequent alleles observed in the group of women with and without RSA were: HLAA* 02 (56%) and (49%), HLA-DRB1*13 (31%) and (39%) respectively - there was no statistical significative difference when compared among the groups for this alleles; HLA-A*24 (12%) e (25%), (OR: 0.41; 95% CI: 0.18-0.92; p=0.028); HLA-A*34 (8%) e (1%), (OR: 8.61; 95% CI: 1.06-187.04; p=0.034); HLA-B*35 (16%) e (41%) (OR: 0.27; 95% CI: 0.13 0.56; p=0.0002). The most frequent haplotypes observed in the group of women with and without RSA were: A*02DRB1*16 (12%) e (2%) (OR: 6.68; 95% CI: 1.36 44.52; p=0.012) respectively. In this research, DRB1* locus in women with RSA was in linkage disequilibrium (p=0.01.). The high frequency of HLA-A*02 and HLA-DRB1*13 alleles in this study was due to the wide distribution of this allele in the population of Maranhão. HLA-A*24 e HLA-B*35 alleles were considered as a protection factor and HLA-A*34 allele was considered as a risk factor to RSA. The A*02DRB1*16 haplotype was the most frequent and considered as a risk factor to RSA. In order to confirm the observed results in this research, a study involving a higher sample size is necessary as well as genetic epidemiology researches to shed light on the role of HLA antigens and/or its connection to other genes as a risk factor.<br>Abortamento Espontâneo Recorrente (AER) caracteriza-se por duas ou mais perdas conceptuais espontâneas e consecutivas antes da 20ª semana de gestação, acometendo entre 1% e 2% das mulheres em idade reprodutiva. Fatores genéticos, anatômicos, endócrinos, infecciosos e imunológicos, por meio de mecanismos que relacionam o Complexo Principal de Histocompatibilidade (CPH) e a frequência de determinados antígenos HLA (Antígeno Leucocitário Humano), estão associados ao AER. O gene HLA localiza-se no braço curto do cromossomo 6 entre as regiões 6p21.31 e 6p21.33, é herdado em bloco e expresso em co-dominância. O mesmo exerce uma grande influência na modulação e indução da tolerância materna durante a gestação. Esta pesquisa teve como objetivo verificar as frequências alélicas dos loci HLA-A*, -B* e - DRB1* em mulheres com e sem AER. Realizou-se um estudo caso-controle em 200 mulheres (100 para cada grupo), entre 18 e 35 anos de idade. Todas as amostras foram tipificadas pelo método PCR-SSOP (Reação em cadeia da Polimerase Sondas de Oligonucleotídios de Sequências Especificas). Os alelos mais frequentes tanto em mulheres com e sem AER foram, respectivamente: HLA-A*02 (56%) e (49%), HLADRB1* 13 (31%) e (39%)-embora sem resultado estatisticamente significante; HLAA* 24 (12%) e (25%), (OR: 0,41; 95% IC: 0,18-0,92; p=0,028); HLA-A*34 (8%) e (1%), (OR: 8,61; 95% IC: 1,06-187,04; p=0,034); HLA-B*35 (16%) e (41%) (OR: 0,27; 95% IC: 0,13 0,56; p=0,0002). Os haplótipos mais frequentes em mulheres com e sem AER foram, respectivamente: A*02DRB1*16 (12%) e (2%) (OR 6,68; 95% IC: 1,36 44,52; p=0,012). No presente estudo, apenas o locus DRB1* apresentou desequilíbrio de ligação significante (p=0,01) em mulheres com AER. A elevada frequência dos alelos HLA-A*02 e HLA-DRB1*13 é justificada pela ampla distribuição desses alelos na população maranhense. Os alelos HLA-A*24 e HLA-B*35 apresentaram-se como um fator de proteção e o alelo HLA-A*34 um fator de risco para AER. Para as associações haplotípicas, o haplótipo A*02DRB1*16 foi mais frequente em mulheres com AER, sendo um fator de risco para este grupo. Para a ratificação dos resultados deste trabalho, faz-se necessário aumentar o número amostral, bem como estudos de epidemiologia genética para o melhor entendimento do papel dos antígenos HLA e/ou sua ligação a outros genes como fator de risco para o AER.

Fundamentos: A porfiria cutânea tardia é a forma mais comum das porfirias e caracteriza-se pela diminuição da atividade da enzima uroporfirinogênio descarboxilase. Há vários relatos da associação das mutações do gene HFE da hemocromatose hereditária com porfiria cutânea tardia no mundo, mas até hoje apenas um estudo foi realizado no Brasil. Objetivo: Estudar a associação da porfiria cutânea tardia com as mutações C282Y e H63D do gene HFE da hemocromatose hereditária. Identificar a associação com etilismo, hepatite C, hepatite B e infecção pelo HIV e relacioná-los com a presença ou não das mutações do gene HFE e estudar retrospectivamente a resposta terapêutica à cloroquina. Métodos: Estudo ambispectivo para detectar as mutações C282Y e H63D em 60 pacientes com porfiria cutânea tardia no período de 2003 até 2012. O histórico familiar, etilismo, hepatite C, hepatite B e anti-HIV foram investigados. O estudo das mutações HFE foi realizado com PCR em tempo real. A resposta terapêutica foi avaliada utilizando a dosagem das porfirinas urinárias (urina de 24 horas), o perfil de ferro (ferro sérico, ferritina e saturação de transferrina) e as enzimas hepáticas antes e após a remissão bioquímica. Resultados: A frequência dos alelos das mutações foi significativamente mais elevada nos pacientes com PCT para C282Y (8,3% versus 1,77%, odds ratio 5,02, IC [95%] = [4,1%; 14,8%], p=0,0001) e H63D (27,5% versus 14,05, odds ratio 2,32, IC [95%] = [19,7%; 36,4%], p=0,0004) em relação à população grupo controle. A hepatite C estava presente em 41,7% dos pacientes e estava associada à ingestão de álcool em 71,7% dos casos. Conclusões: As mutações HFE e a expressão clínica da hemocromatose hereditária podem contribuir isoladamente para o desencadeamento da PCT, independente-mente da presença de outros fatores precipitantes; o que torna a pesquisa das mutações HFE um exame necessário nos pacientes com PCT. Nos pacientes homozigotos para C282Y e heterozigotos compostos (C282Y/H63D) a flebotomia é o tratamento de primeira escolha. A porfiria cutânea tardia pode ser um marcador cutâneo para a hemocromatose e o dermatologista pode auxiliar no seu diagnóstico e tratamento precoce.<br>Background: Porphyria cutanea tarda (PCT) is the most common form of porphyria and is characterized by the decreased activity of the uroporphyrinogen decarboxylase enzyme. Several reports associated HFE gene mutations of hereditary hemochromatosis with PCT worldwide, although up to date only one study has been conducted in Brazil. Objective: Study the association between porphyria cutanea tarda and C282Y and H63D mutations in the HFE gene of hereditary hemochromatosis. Identify the association with alcoholism, hepatitis C, hepatitis B and HIV infection and relate them with the presence or absence of the HFE gene mutations and study retrospectively the therapeutic response to chloroquine. Methods: Ambispective study in the period from 2003 to 2012 to detect the C282Y and H63D mutations in 60 patients with porphyria cutanea tarda. The family history, alcoholism, hepatitis C, hepatitis B and HIV were investigated. HFE mutations were held with real-time PCR. The therapeutic response was assessed using the urinary porphyrins (24h urine), the iron profile (serum iron, ferritin and transferrin saturation) and the liver enzymes, before and after biochemical remission. Results: The frequency of alleles of the mutations were significantly higher in patients with PCT for C282Y (8.3% vs. 1.77%, odds ratio 5.02, CI [95%] = [4.1%; 14.8%], p = 0.0001) and H63D (27.5% vs. 14.05, odds ratio 2.32, CI [95%] = [19.7% and 36.4%], p = 0.0004) in relation to group control population. Hepatitis C was found in 41.7% of the patients and was associated with the ingestion of alcohol in 71.7% of cases. Conclusions: The HFE mutations and clinical expression of hereditary hemochromatosis can contribute in an isolated manner to the outbreak of PCT, independently of the existence of other precipitating factors. This makes the search for HFE mutations necessary in patients with PCT. In patients who are homozygous for C282Y and compound heterozygotes (C282Y/H63D) phlebotomy is the treatment of first choice. Porphyria cutanea tarda can be a cutaneous marker for hemochromatosis and the dermatologist can help in its diagnosis and early treatment.

Abstract Demographic history and natural selection are central forces shaping the genetic diversity of populations. Knowledge on these forces increases understanding of processes shaping genetic variability of populations. In this PhD thesis I investigated demographic history and selection in multiple populations of Arabidopsis lyrata, an outcrossing herbaceous plant species of the Brassicaceae family. Due to its wide distribution in the temperate and boreal regions, A. lyrata serves as a good model system to study population genetic consequences of colonization of northern latitudes. The first aim of this study was to characterize the demographic and colonization history of the species using site frequency spectra estimated from whole-genome diversity data. Another aim was to detect genetic loci targeted by recent selective sweeps at genome-wide scale as well as at candidate flowering time genes. Patterns of genome-wide selection at linked sites (linked selection) were also compared between populations of Capsella grandiflora and A. lyrata with contrasting demographic histories. Evidence for strong effective population size decline in the past few hundred thousand years was detected in A. lyrata populations species-wide. This study also suggests recent Scandinavian colonization from an unknown refugium, distinct from the Central European source population. Selection analyses revealed loci targeted by positive selection in two Scandinavian lineages after the recent population split as well as selective sweeps in flowering time genes in the colonizing populations. In comparison with the studied C. grandiflora population, the Norwegian A. lyrata population had weaker purifying selection and no evidence for reduction of diversity around genes was found. This thesis offers novel information on species colonization history and its genome-wide effects, which is important for understanding the framework of local adaptation<br>Tiivistelmä Populaation demografinen historia ja luonnonvalinta ovat keskeisiä populaation perinnöllisen muuntelun muokkaajia. Näiden tekijöiden tutkimus on tärkeää eliöiden sopeutumisen ymmärtämiselle. Tässä väitöskirjassa tutkin demografista historiaa ja valintaa monivuotisen ristisiittoiseen ruohovartisen Brassicaceae-heimon kasvilajin idänpitkäpalon (Arabidopsis lyrata) useissa eri populaatioissa. Idänpitkäpalko on erinomainen mallilaji pohjoiseen ympäristöön sopeutumisen tutkimukseen, koska sen toisistaan eristäytyneet paikalliset populaatiot ovat levittäytyneet laajalle boreaalisella ja lauhkealla ilmastovyöhykkeellä. Tutkimuksen tarkoituksena oli luonnehtia populaatioiden demografista historiaa ja kolonisaatioreittejä käyttäen koko perimän laajuisesta muunteluaineistosta estimoituja alleelifrekvenssispektrejä. Lisäksi koko perimän laajuista aineistoa sekä kukkimisaikaa ohjaavien geenien sekvenssejä käytettiin positiivisen luonnonvalinnan merkkien tunnistukseen. Genominlaajuista kytkeytynyttä valintaa vertailtiin toiseen ristisiittoiseen Brassicaceae-heimon lajin Capsella grandifloran populaatioon, jonka demografinen historia poikkeaa huomattavasti tutkituista idänpitkäpalon populaatioista. Tutkimuksessa havaittiin, että kaikissa tutkituissa idänpitkäpalon populaatioissa tehollinen populaatiokoko oli pienentynyt viimeisen muutaman sadantuhannen vuoden aikana. Kolonisaatiohistorian tarkastelu osoitti, että idänpitkäpalon skandinaaviset populaatiot ovat todennäköisesti peräisin keskieurooppalaisesta refugiosta erillisestä läntisestä refugiosta. Skandinavian kolonisaation yhteydessä vaikuttaneen positiivisen luonnonvalinnan merkkejä havaittiin useissa eri genomin osissa sekä erityisesti valojaksoa mittaavissa geeneissä. Tämä kertoo erilaisiin valojaksoihin sopeutumisen tärkeydestä skandinaavisen kolonisaation yhteydessä. Verrattuna tutkittuun C. grandifloran populaatioon, idänpitkäpalolla puhdistavan valinnan havaittiin olevan heikompaa ja muuntelun vähenemistä geenien ympärillä ei havaittu. Tämä tutkimus tarjoaa uutta tietoa Skandinavian kolonisaatiohistoriasta ja sen genominlaajuisista vaikutuksista. Tutkimuksessa tuotettua tietoa voidaan hyödyntää paikallisen sopeutumisen ymmärtämisessä

A resposta do LH e do FSH ao estímulo com GnRH, realizado em estádio pré-puberal em pacientes com hipopituitarismo acompanhados até a idade puberal, são úteis para predizer o diagnóstico da deficiência de gonadotrofinas, principalmente nas meninas. O estudo da região codificadora do gene LH em pacientes com hipogonadismo hipogonadotrófico e concentrações normais de LH revelou 5 variantes alélicas. A freqüência das variantes alélicas Arg8 e Thr15 foi similar entre hipogonádicos e adultos normais e a sua presença não interferiu nas concentrações séricas do LH. O estudo das isoformas do LH mostrou um predomínio das isoformas ácidas do LH em hipogonádicos e indivíduos normais, não permitindo atribuir à sua presença a baixa atividade biológica do LH imunorreativo encontrado em 13% dos hipogonádicos<br>LH and FSH responses to GnRH stimulation carried out in the pre-pubertal stage in patients with hypopituitarism followed until the pubertal stage are useful tools for predicting the gonadotropin deficiency diagnosis, especially in girls. The study of the codifying region of the LH gene in patients with hypogonadotropic hypogonadism and normal LH levels disclosed 5 allelic variants. The frequencies of the allelic variants Arg8 and Thr15 were similar between hypogonadic and normal adults, and their presence did not alter serum LH levels. The study of LH isoforms showed a predominance of acid LH isoforms in hypogonadic and normal subjects, which does not allow us to ascribe to their presence the low biological activity of the immunoreactive LH, found in 13% of the hypogonadic individuals

FUNDAMENTOS: O polimorfismo e a atividade da enzima conversora da angiotensina (ECA) contribuem, de forma significante, na expressão fenotípica e no prognóstico de pacientes com cardiomiopatia. OBJETIVOS: Determinar o polimorfismo da ECA, realizar a sua dosagem sérica e correlacioná-los com o grau de hipertrofia miocárdica e o índice de massa do ventrículo esquerdo em pacientes com cardiomiopatia hipertrófica (CMH) nas formas familiar e não familiar. CASUÍSTICA E MÉTODO: Foram estudados 136 pacientes consecutivos com CMH (69 da forma familiar e 67 da forma não familiar) com média de idade de 40,53±17,45 anos, sendo 76 do sexo masculino. Os indivíduos foram submetidos ao ecocardiograma para obtenção das medidas do septo interventricular, parede posterior e massa do ventrículo esquerdo e coleta de sangue para determinação do polimorfismo e dosagem sérica da atividade da ECA. RESULTADOS: Quanto ao genótipo do polimorfismo do gene da ECA, encontramos DD 47(35%), ID 71(52%) e II 18 (13%), sendo que do genótipo DD 34% na forma familiar e 36% na forma não familiar. A média da atividade da ECA foi de 56.414±19.236 para os pacientes com CMH na forma familiar e de 55.085±22.634 para a forma não familiar (p = 0,714). A média do índice de massa do ventrículo esquerdo na forma familiar foi 154±63 g/m2 e na forma não familiar foi 174±57 g/m2 (p = 0,008). A média do septo interventricular nas formas familiar e não familiar foi, respectivamente, 19±5 mm e 21±5 mm (p = 0,020). A média da parede posterior do ventrículo esquerdo nas formas familiar e não familiar foi, respectivamente, 10±2 mm e 12±3 mm (p = 0,0001). Não observamos correlação entre o polimorfismo e o grau de hipertrofia miocárdica (p = 0,651). Houve correlação positiva entre a atividade da ECA e o índice de massa do ventrículo esquerdo (p = 0,038). Os pacientes com a forma familiar, pela curva de regressão logística, possuíam o risco de apresentar índice de massa maior ou igual 190 g/m2, somente com o dobro do valor da atividade da ECA, quando comparados aos pacientes com a forma não familiar (p = 0,022). CONCLUSÕES: Não houve diferença estatisticamente significante entre o genótipo do polimorfismo e da atividade da ECA nos pacientes com CMH nas formas familiar e não familiar. Não houve correlação entre o polimorfismo da ECA e o grau de hipertrofia miocárdica. Houve correlação positiva entre a atividade da ECA e o índice de massa do ventrículo esquerdo.<br>BACKGROUND: The polymorphism and the activity of the angiotensin converting enzyme (ACE) contributes of significant form in the phenotypic expression and the prognostic of patients with cardiomyopathy. OBJECTIVES: To determine the ACE polymorphism and ACE plasma levels in patients with hypertrophic cardiomyopathy (HCM) in the familial and nonfamilial forms and to correlate it with the degree of myocardium hypertrophy and with the left ventricular mass index. PATIENTS AND METHODS: 136 consecutive patients with HCM (69 of familial and 67 of nonfamilial forms) were studied. The mean age was 40.53±17.45 years, 76 were male. The individuals were submitted to the Echo-Doppler for the measurement of interventricular septum, wall thickness and the left ventricular mass index. The blood samples were taken for extraction of the DNA for the polymerase reaction and measurement of ACE plasma levels. RESULTS: Regarding the genotype of the ACE gene polymorphism, we found DD 47 (35%), ID 71 (52%) and II 18 (13%), being that of genotype DD 34% in the familial and 36% in the nonfamilial forms. The mean of the activity of the ACE was 56.414±19.236 for the patients with HCM in the familial form and 55.085±22.634 in the non familial form (p = 0.714). The mean of the left ventricular mass index in the familial form was 154±63 g/m2 and in the nonfamilial form was 174±57 g/m2 (p = 0.0080). The mean of interventricular septum in the familial and nonfamilial forms was 19±5 mm and 21±5 mm (p = 0.0200), respectively. The mean of the wall thickness in the familial and nonfamilial forms was 10±2 mm and 12±3 mm (p = 0.0001), respectively. We did not observe correlation between the polymorphism and the degree of myocardium hypertrophy (p = 0.651). A positive correlation between the activity of the ACE and the left ventricular mass index (p = 0.038) was observed. In patients with the familial form, using a logistic regression curve, they had the risk to present the left ventricular mass index >= 190 g/m2, only with the double of the value of the activity of the ACE, when compared with the patients in the nonfamilial form (p = 0.022). CONCLUSIONS: There was no difference between the patients with HCM in the familial and nonfamilial forms regarding genotype of the polymorphism and activity of the ACE. There was no correlation between the polymorphism of the ACE with the degree of myocardium hypertrophy. Positive correlation with the activity of the ACE and the left ventricular mass index was observed.

Nous avons etudie l'evolution intraspecifique de la gorgebleue a miroir luscinia svecica. Nous avons teste, en premier lieu, si les sous-especes decrites correspondaient a des entites genetiques claires. En sequencant une partie de la region de controle et du gene du cytochrome b situes sur l'adn mitochondrial, nous avons revele que les sous-especes sont en fait tres proches genetiquement (region de controle: 0,00168 0,00001 (divergence moyenne es), cyt. B : 0,00344 0,00017, pour les deux sous-especes les plus differentes morphologiquement). Les sous-especes ont donc diverge rapidement apres un goulot d'etranglement recent, comme le montre le nombre eleve d'haplotype ne divergeant que par quelques mutations. L'emergence de morphes differents s'est probablement produite sous l'influence de pressions selectives fortes ou par derive genetique dans des zones separees apres un second goulot d'etranglement. La selection sexuelle pourrait avoir entraine la divergence des caractere sexuels secondaires comme la couleur du miroir. Pour qu'il y ait selection sexuelle, une variance dans les succes reproducteurs individuels doit exister. Nous avons donc etudie le systeme de reproduction d'une population de gorgebleue nichant dans les marais salants de guerande (bretagne) pour evaluer les variations des succes reproducteurs grace aux empreintes genetiques. Chez les especes monogames, il est en effet possible de maximiser son succes reproducteur via des fecondations hors-couples. Nous avons utilise les aflp (amplified fragment length polymorphism) pour mesurer le taux de paternites hors-couples dans les nichees. Comme nous le pensions, 63,8% des nichees contiennent au moins un jeune issu d'une fecondation hors-couple (= 41,9% des jeunes). Cela souligne le role potentiel d'une forte selection sexuelle chez cette espece. Par contre, aucun biais de la sex-ratio vers les males en fonction de l'attractivite du pere n'a ete mis en evidence dans les couvees.

Cette thèse porte sur l'étude de la modélisation de l'évolution, par des processus markoviens, de l'effectif d'un gène donné au cours des générations dans une population à taille limitée. Dans une première partie, nous faisons un recensement des différents types de chaînes de Markov homogènes utilisées dans la littérature pour une telle modélisation. Quand la taille de la population est grande, il est possible d'obtenir la convergence de ces chaînes de Markov vers des processus de diffusion homogènes grâce aux théorèmes de convergence qui font l'objet de la deuxième partie. La troisième partie de cette thèse est consacrée aux différentes méthodes de calcul des temps moyens avant absorption qui correspondent ici aux temps moyens avant disparition ou invasion complète du gène donné en partant de différentes conditions initiales. La quatrième partie propose une modélisation simple d'une maladie génétique, la drépanocytose, et l'influence du paludisme comme facteur de sélection sur l'évolution de cette maladie en Afrique

RFLP des gènes de l'inhibiteur de la trypsine inter alpha chez l'homme, déterminisme génétique et fréquence allélique de ces marqueurs dans une population de référence et dans une population constituée d'individus non déficitaires en alpha-1-antitrypsine souffrant d'emphysème pulmonaire

Os alelos HLA-DPB1*04 e HLA-DRB1*15 estão fortemente associados à Granulomatose com poliangeíte (GPA). Neste estudo, analisamos se os pacientes brasileiros com diagnóstico de GPA apresentam uma base genética na região HLA. Conduzimos um estudo caso-controle, em que analisamos os alelos da região HLA classe I e II em 55 pacientes com diagnóstico de GPA, atendidos no ambulatório de Vasculites Pulmonares do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, e comparamos com os resultados de 110 controles saudáveis. Comparamos também quatro diferentes apresentações clínicas da GPA e a positividade do anticorpo anticitoplasma de neutrófilos (ANCA) com os alelos da região HLA classe I e II. Foi também construída uma árvore de decisões, usando o algoritmo de CART, para a verificação da associação entre os alelos HLA e GPA. Como resultados, observamos que a GPA esteve fortemente associada à presença dos alelos DPB1*04 e DRB1*15 (p = 0,007, odds ratio [OR]: 2,9, 95% intervalo de confiança [IC]: 1,09-3,8; p = 0,006, OR: 2,87, 95% IC: 1,44-4,75, respectivamente) e não à presença do alelo DRB1*04. O alelo DRB1*13 esteve associado com proteção contra GPA (p = 0,042, OR: 0,42, 95% CI: 0,21-0,99). O alelo DPB1*04 esteve significativamente associado a GPA e ANCA-C positivo (OR: 5,47) e à presença de insuficiência renal aguda (p = 0,01037). Concluímos que houve uma interdependência significativa entre os alelos DPB1*0401, DPB1*0402, DRB1*13, C*2 e GPA. Na população estudada, quando o alelo DPB1*04 esteve presente em homozigose, o risco de GPA foi de 81%. Quando o alelo DPB1*0401 esteve ausente ou em heterozigose com o DPB1*0402, como o outro alelo, ou DPB1*0402 esteve em homozigose, o risco da GPA foi de 52,9%. No caso de ausência dos alelos DPB1*0401, DPB1*0402 e DRB1*13, a presença do alelo C*2 aumentou o risco da GPA para 62,5%. Finalmente, na ausência do alelo DPB1*0401 e DPB1*0402 e na presença do alelo DRB1*13, o risco de GPA diminuiu para 0%<br>The alleles HLA-DPB1*04 and HLA-DRB1*15 are strongly associated with granulomatosis with polyangiitis (GPA). In this study, we examined whether Brazilian patients with GPA had an HLA region genetic background. We conducted a case-control study, in which we analysed alleles of HLA region class I and II from 55 patients with GPA (at the Pulmonary Vasculitis Clinic of the University of São Paulo) and compared the results with those from 110 healthy controls. Comparisons were also performed for 4 different clinical presentations of GPA and anti-neutrophil cytoplasmic antibody (ANCA) positivity and the HLA class I and II region alleles. A tree model decision analysis was conducted using CART algorithm. Our results showed that GPA was strongly associated with alleles DPB1*04 and DRB1*15 (p = 0.007, odds ratio [OR]: 2.9, 95% confidence interval [CI]: 1.09-3.8; p = 0.006, OR: 2.87, 95% CI: 1.44-4.75, respectively) and not with the allele DRB1*04. DRB1*13 allele was associated with protection against GPA (p = 0.042, OR: 0.42, 95% CI: 0.21-0.99). DPB1*04 was significantly associated with GPA plus positive C-ANCA (OR: 5.47) and acute renal failure (p = 0.01037). We concluded that there was a significant interdependence among alleles and GPA. In our population, when allele DPB1*04 was presented in homozygous, the risk of GPA was 81%. When DPB1*0401 allele was absent or heterozygous with DPB1*0402 as the other allele, or DPB1*0402 was homozygous, the risk of disease was 52.9%. If DPB1*0401, DPB1*0402, and DRB1*13 were absent, the presence of C*2 increased the risk of GPA to 62.5%. Finally, in the absence of DPB1*0401 and DPB1*0402 and the presence of DRB1*13, the risk of GPA decreased to 0%

>Magister Scientiae - MSc<br>This is a pilot study to investigate the relationship between disease gene status and the structure of the human genome with specific reference to regions of recombination. It compares certain characteristics of a control set of genes, with no reported association or function in any known disease, with a second set of well-curated genes with a known association to a disease. One of the benefits of recombination is the introduction of new combinations of genetic variation in the genome. Recombination hotspots are regions on the chromosome where higher than normal frequencies of breaking and rejoining between homologous chromosomes occur during meiosis. The hotspot regions exhibit both a non-random distribution across the human genome and varying frequencies of breaking and rejoining. The study analyzed a set of features that represent general properties of human genes; namely base composition (percentage GC content), genetic variation (single nucleotide polymorphisms - SNPs), gene length, and positional effect (distance from chromosome end), in both the disease-associated gene set and the control set. These features were linked to recombination hotspots in the human genome and the frequency of recombination at these hotspots. Descriptive statistics was used to determine differences between the occurrences of these features in disease-associated genes compared to the control set, as well as differences in the occurrence of these same features in subset of genes containing an internal recombination hotspot compared to the genes with no internal recombination hotspot. The study found that disease-associated genes are generally longer than those in the control set, which is consistent with previous studies. It also found that disease-associated genes are much more likely to contain a recombination hotspot than those genes with no disease association. The study did not, however, find any association between disease gene status and the other set of features; namely GC content, SNP numbers or the position of a gene on the chromosome. Further analysis of the data suggested that the increased probability of disease-associated genes containing a recombination hotspot is most likely an effect of longer gene length and that the presence of a recombination hotspot is not sufficient in its own right to cause disease gene status.

Orientadores: Joyce M. Annichino-Bizzacchi, Christine Hackel<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas<br>Made available in DSpace on 2018-07-23T08:15:34Z (GMT). No. of bitstreams: 1 Mendes_ChristianePatriciadeOliveira_M.pdf: 3747507 bytes, checksum: 314473a43a2b60b23c30e4583bb31f97 (MD5) Previous issue date: 1997<br>Resumo: A cascata da coagulação sanguínea humana, em condições normais, é regulada por vários mecanismos naturais de anticoagulação. Entre esses mecanismos está a chamada Via da Proteína c (PC) Anticoagulante. A PC é uma proteína hepática dependente da vitamina K, que, quando ativada, exerce uma potente atividade anticoagulante e pró-fibrinolítica. Os pacientes com deficiência de PC apresentam quadro clínico caracterizado por fenômenos tromboembólicos Apenas 2-5% dos pacientes com trombose venosa apresentam deficiência de Pc. Contudo, devido à importância desse anticoagulante natural, a diminuição de sua concentração, mesmo que ainda dentro dos limites da normalidade, talvez possa ser um fator de risco a mais, que contribua para a trombose nesses pacientes. Recentemente foram descritos três polimorfismos na região promotora do gene da PC; um polimorfismo C/T, na posição -1654 e um polimorfismo A/G, : um polimorfismo na posição 1641 A/T, na posição -1476 (REITSMA, 1993). A análise desses três polimorfismos, em 24 famílias normais da Holanda, demonstrou que os três haplótipos mais freqüentes eram CAA, CGT e T AA, e representavam 88% dos casos. Segundo os autores os polimorfismos CGT e T AA tinham relação com a concentração da atividade plasmática de PC, na qual o genótipo CGT está associado a um risco elevado de trombose venosa, uma vez que foi mais freqüente nos indivíduos com trombose (risco relativo associado a doença de 1.9 ou OR de 1.9) frente ao genótipo T AA (OR de 1.6). Neste trabalho determinamos a freqüência destes 3 polimorfismos em três grupos étnicos da população brasileira (caucasóide, negróide e indígena), e em pacientes com trombose venosa mas sem deficiência congênita de Pc. Analisamos se em nossa população havia uma correlação entre o genótipo e a concentração da atividade de PC, ou se algum dos genótipos estava associado ao risco de trombose. A população indígena foi constituída por 87 indivíduos. Observou-se uma maior freqüência de homozigotos nos três genótipos estudados (CC - 52,9%; GG - 54% e AA 70,1 %), que também se manteve na análise considerando os três genótipos, simultaneamente (CC/GG/ AA -21,8%). Tal resultado leva-nos crer que os índios brasileiros estudados no presente trabalho ainda não sofreram folie influência da miscigenação, bastante comum em nosso país. Esse grupo indígena tem sua tribo em localização razoavelmente isolada do convívio do homem civilizado, o que resulta na pouca variação genômica (baixo fluxo gênico). A população de doadores caucasóide e negróide foi constituída por 216 homens e 50 mulheres. A população caucasóide foi constituída por 188 indivíduos (147 homens e 41 mulheres) e a negróide por 78 indivíduos (69 homens e 9 mulheres). Quando esses grupos foram analisados em conjunto, observou-se uma maior freqüência de heterozigotos nos 3 polimorfismos (CT 59,4% e AG - 59,4%; AT-70,7%). A análise conjunta dos 3 polimorfismos revelou uma predominância do genótipo heterozigoto (CT/AG/AT - 27,4%). Isto sugere um elevado fluxo gênico, o que é esperado, visto a alta taxa de miscigenação em nossa população. A freqüência dos polimorfismos na raça caucasóide foi CT-57%, AG-59%; e AT-64%; e na raça negróide CT -65%, AG-60% e A T -77%. A conjugação dos 3 polimorfismos mostrou que na raça caucasóide houve predominância do genótipo CT/AG/AT (28,3%) assim como na raça negróide (30,1 %). Sendo que as populações caucasóide e negróide não apresentaram diferença significativa. A dosagem da atividade de PC na população de doadores variou de 70 a 150%, com uma média de 102%. Contudo, não se evidenciou nenhuma relação entre os níveis de PC e os genótipos, exceto para o polimorfismo A/T, conforme descrito na população holandesa. Também, o genótipo CC/GG/TT, associado a níveis diminuídos de PC naquela população foi praticamente nulo (menor que 1%) em nossa população de brasileira, não permitindo qualquer análise. A média da atividade de PC dos 2 genótipos mais freqüentes (CT/AG/AT e CC/AG/AT) na população de doadores caucasóide e holandesa foi semelhante (p=0,039). Verificou-se nos doadores uma diferença significativa nos níveis de PC no polimorfismo 3, entre AA e A T com uma concentração da atividade de 108% e 99% (p=O, 015), respectivamente, associada a homozigose CC, que também mostrou uma diferença significativa entre CC/ AA e CC/AT com uma concentração da atividade de 112.76% e 99.96% (p=0,004), respectivamente). Isto poderia sugerir que o polimorfismo AT em homozigose para o C influencia na diferença dos níveis de PC, em relação ao polimorfismo 3. Como os resultados na população holandesa são opostos aos nossos, pois aqueles indivíduos com o genótipo CC/ A T exibem níveis de PC mais elevados, não permitem que se faça qualquer afirmativa com segurança. Na população com trombose, houve predominância do sexo feminino, sendo 35 homens e 88 mulheres. Quanto à raça, também houve uma predominância de indivíduos caucasóides (n=108) sobre os negróides (n=15). Verificou-se uma maior freqüência de heterozigosidade dos 3 Polimorfismos (CT-65,5%; AG-54% e AT-55,5%), assim como do genótipo heterozigoto (CT/AG/AT-21,1%). Mesmo quando os pacientes foram separados por raça, também verificou-se um maior índice de heterozigozidade, sendo CT -64%;e AG-52,3% e A T -54% no caucasóides e, CT -75%; AG-66,7% e A T - 77,7% nos negróides. Sendo que as populações caucasóide e negróide não apresentaram diferença significativa. o polimorfismo 2 em homozigose para o A foi significativamente mais freqüente na população com trombose (46%), quando comparada à população de doadores (24.4%) (p=0.005). Tais dados sugerem que o genótipo AA é um fator de risco para trombose (aR 1.93, 95% CI, 1.11 a 3.24). Contudo, em nossa população esse genótipo não está associado a níveis Por outro lado, o haplótipo CGT, considerado um fator de risco para trombose nos pacientes holandeses, foi encontrado em apenas 1 % dos nossos pacientes. Apesar de serem 2 populações diferentes, caso esse genótipo fosse um fator de risco, esperaríamos uma maior freqüência em nossos pacientes, assim como verificamos um aumento da prevalência de outras alterações genéticas associadas à trombose, como o fator V de Leiden, a mutação da protrombina e a mutação no gene da metilenotetrahidrofolatoredutase. A freqüência dos genótipos com maior e menor concentração da atividade de PC não é diferente entre doadores e pacientes com trombose, sugerindo que esses polimorfismos parecem não estar diretamente ligados ao risco de trombose. Portanto, nossos resultados demostraram que em nossa população, tanto de doadores como de pacientes com trombose, esses 3 polimorfismos praticamente não estão associados com os níveis de atividade plasmática de PC. Esses resultados mais uma vez ilustram a grande diversidade genética, nas populações humanas, mesmo entre grupos étnicos semelhantes, apontando para a importância de se analisar individualmente cada população, para que as conclusões possam ser bem fundamentadas<br>Abstract: Protein C (PC) is one of the major inhibitors of blood coagulation. After activation by thrombin-thrombomodulin complex in the endothelium, PC inhibites activated factors V and VIII. It also exerts a profibrinolytic activity, trough neutralization of plasminogen activator inhibitor-l (PAI-I). PC deficiency is associated with clinical thromboembolic disease. The incidence of PC deficiency in patients with thrombosis is 2-5%. However, since the physiological significance of the PC anticoagulant activity, a decreased plasmatic concentration, even in the normal range, could be a factor contributing for thrombosis in patients without a congenital PC deficiency. Recently, Spek et aI (1993) described 3 polymorphisms in the promoter region of PC gene: AlT in the position 1476; C/T in the position 1654 and AlG in the position 1641. The genotypic variation of these polymorphisms were associated with plasma PC levels and thrombotic risk (Spek et aI 1995). We determined the frequency of these polymorphisms in 3 ethinic groups of the Brazilian population (caucasian, black and indian) and in patients with thrombosis disease, without PC deficieI1cy. We also verified ifthere is an association between genotype and PC concentration, and with thrombotic risk. The indian group comprised 87 individuais. Homozigosity was prevalent in all polymorphisms (CC-52.9%, GG-54% and AA-70.1%) and in the genotype (CC/GG/AA-21.8%). These results suggest that this group was not miscegeneous, a finding very common in Brazilian population, probably because the tribe of these indians is isolated from the civilization. Caucasian and black population comprised 216 men and 50 women; there was 188 Caucasians (147 men and 41 women) and 78 Blacks (69 men and 9 women). Heterozigous polymorphism was more frequent in caucasian and black, as well as complete heterozygote CT/AG/AT (26.1% and 30.1%, respectively). Although before blood collection the individuaIs were selected only if untill the third ancestry were from the same origin, our results favour a high genetic flow. Mean PC activity levels in caucasian and blacks was 102%. However there was no correlation between the genotypic variation and PC concentration. IndividuaIs with the 2 more frequent genotype (CT/AG/AT and CC/AG/AT) had mean PC levels similar to that described in the Dutch study. There was a difference in mean PC levels in A/T polymorphism, between AA and A T (p=0.015), that also was significative between CC/AA and CC/AT (p=0.004). This could suggest that the first polymorphism homozigous for C influence the difference in PC concentration related to A/T polymorphism. However, in the Dutch population the results are in opposite, since the individuaIs with CC/ A T genotype showed increased PC levels. Thrombotic population comprised 35 men and 88 women, 108 caucasian and 15 black. The complete heterozigous CT/AG/AT was the more frequent genotype (21-1%), and not differ from the black and caucasian population. Even when they were separated according to the race, there was no difference between the frequency in the groups. When the polymorphisms were analysed individually, the second polymorphism homozigous for A was significantly more frequent in caucasian patients with thrombosis related to the caucasian normal population (p=0.005). To ascertain whether this polymorphism genotype was associated with a higher risk for thrombosis, we compare the number of patients and control caucasian subjects with the AA and ATor TT genotypes. The results indicated that having the AA genotype yields an OR of 1.93 (95% CI, 1.11 to 3.24) compared to the other genotypes. However, AA genotype is not associated with decrease in PC levels. Indeed, this finding was not verified in Dutch population. On the other hand, in Dutch study a clear correlation between PC promoter genotype and PC plasma levels was found; individuaIs with CGT haplotype exibited a PC activity 22% lower than individuaIs with T AA haplotype. They also considered CGT haplotype a risk factor for thrombosis. Although Brazilian and Dutch populations, we should expected that CGT genotype being a risk factor for thrombosis was more prevalent in our population, like factor V Leiden, variant prothrombin gene and methylene tetrahydrofolate reductase mutation, wich were increased in our and in Europe thrombotic patients, In conclusion, our results demonstrated that in our population these polymorphisms were not related to PC concentration. It is also important to point out the great genetic variety in human populations, even in the same ethynic groups, rising the 'importance to analyse individually each population<br>Mestrado<br>Farmacologia<br>Mestre em Ciências<br>FAPESP

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Biotecnologia e Biociências, Florianópolis, 2011<br>Made available in DSpace on 2012-10-26T01:26:49Z (GMT). No. of bitstreams: 1 295025.pdf: 2894933 bytes, checksum: 67593ffc68e4727beec377fc206b3a35 (MD5)

Includes bibliographical references (leaves 92-112).<br>In humans and other higher eukaryotes the observation of multiple splice isoforms for a given gene is common. However it is not clear whether all of these alternatively spliced isoforms are a product of true alternative splicing or some are due to DNA sequence variations in human populations. Genetic variations that affect splicing have been shown to cause variation in splicing patterns and potentially are an important source of phenotypic variability among humans. Furthermore, variation in disease susceptibility and manifestation between individuals is often associated with genetic polymorphisms that determine the way in which genes are spliced. Hence, identification of genetic polymorphisms that might affect the way in which pre-mRNAs are spliced is an area of great interest.

Orientador : Carmen Silvia Bertuzzo<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas<br>Made available in DSpace on 2018-08-02T04:23:22Z (GMT). No. of bitstreams: 1 Santos_Kelly_M.pdf: 15332993 bytes, checksum: 39bff3e0afd6a69cc924f944b9927971 (MD5) Previous issue date: 2002<br>Resumo: A Síndrome de Turner (ST), descrita por Henry Turner em 1938, caracteriza-se classicamente por um fenótipo feminino associado à baixa estatura, infantilismo sexual, esterilidade, além de diversas malfonnações. Há evidências de que mutações na enzima metilenotetrahidrofolato redutase (MTHFR), ligada ao metabolismo do ácido fólico, levariam a aberrações cromossômicas devido a fenômenos de hipometilação. No presente estudo nós avaliamos a freqüência das mutações C677T e A1298C no gene da MTHFR em 49 portadoras de ST e em 200 indivíduos controles. O método de análise foi a Reação em Cadeia da Polimerase (PCR) seguida de digestão enzimática específica. Encontramos 26% de pacientes heterozigotas para a mutação C677T, 18% de homozigotas mutantes para a mutação C677T, 22% de pacientes heterozigotas A1298C, 10% de homozigotas mutante 1298C e 14% de heterozigotas para ambas as mutações C677T/A1298C. Nossos resultados indicam uma incidência elevada de indivíduos mutantes C677T (p<0,001) em nossa amostra. Sugerindo que a deficiência da MTHFR pode ser identificada como um fator de risco para nascimentos de crianças com ST<br>Abstract: Henry Tumer described Turner's syndrome (TS) in 1938 and characterized it as a classicaI female phenotype associated with a short stature, sexual irmnaturity,sterility and other maIformations. Evidences exist that methylenetetrahydrofolate reductase (MTHFR) enzyme mutations related to folic acid metabolism lead to chromosomal aberrations due to the hypomethylation phenomenon. This study evaIuates the frequency of C677T and A1298C mutations of the MTHFR gene among 49 individuais with TS and 200 control individuais. An analysisof the results was obtained using the polymerase chain reaction (PCR), which was followed by specific enzymatic digestion. In this study, 26% of patients were heterozygous for the C677T mutation, 18% were homozygous for the C677T mutation, 22% ofthe patients were heterozygous for the A1298C mutation and 14% were heterozygous for both C677T/A1298C mutations. Our results demonstrated a higher incidence of C677T mutant individuais (p<0.001) in this sample. Suggesting that MTHFR deficiency can be defined as a risk factor for the birth of TS children<br>Mestrado<br>Ciencias Biomedicas<br>Mestre em Ciências Médicas