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Mutni, A. N. "Effects on anti-hyperlipidaemic drugs on the liver". Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382585.
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Silberstein, D. J. "The effect of renal failure on the elimination of drugs by the liver". Thesis, University of Leeds, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379649.
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Teng, Shuzhi, i 滕曙智. "Hepatocellular injury induced by endotoxin and galactosamine". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31241037.
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Abumansour, Hamza M. A. "Quantitative pharmacoproteomics investigation of anti-cancer drugs in mouse : development and optimisation of proteomics workflows for evaluating the effect of anti-cancer drugs on mouse liver". Thesis, University of Bradford, 2016. http://hdl.handle.net/10454/15724.
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Minimizing anti-cancer drug toxicity is a major challenge for the pharmaceutical industry. Toxicity is most frequently due to either the direct interaction of the drug on previously unidentified targets or its conversion to metabolites by drug metabolizing enzymes (e.g. CYP450 enzymes) that cause cellular, tissue or organ damage. Pharmacoproteomics is beginning to take a central role in studying changes in protein expression corresponding to drug administration, the results of which, inform about the mode of action, toxicity, and resistance in pre-clinical and clinical stages of drug development. The main aim of this research is to apply comparative proteomics studies on livers from male and female mice xenograft models treated with major anti-cancer drugs (5-flourouracil, paclitaxel, cisplatin, and doxorubicin) and CYP inducer, TCPOBOP, to investigate their effect on protein expression profiles (proteome). Within this thesis, an attention is paid to optimise a highly validated proteomics workflow for biomarker identification. Proteins were extracted from liver microsomes of mice treated in two separate sets; Set A – male (5-fluoruracil, doxorubicin, cisplatin and untreated) or Set B – female (5-fluoruracil, paclitaxel, TCPOBOP and untreated) using cryo-pulverization and sonication method. The extracts were digested with trypsin ii and the resulting peptides labelled with 4-plex iTRAQ reagents. The labelled peptides were subjected for separation in two-dimensions by iso-electric focusing (IEF) and RP-HPLC techniques before analysis by mass spectrometry and database searching for protein identification. Set A and Set B resulted in identification and quantification of 1146 and 1743 proteins, respectively. Moreover, Set A and Set B recovered 26 and 34 cytochrome P450 isoforms, respectively. The microsomal changes after drug treatments were quite similar. However, more changes were observed in the male set. Up-regulation of MUPs showed the greatest distinction in the protein expression patterns in the treated samples comparing to the untreated controls. In Set A, 5-fluoruracil and cisplatin increased the expression of three isoforms (MUP1, 2, and 6), whereas doxorubicin has increased the expression of four isoforms (MUP1, 2, 3, and 6). On the other side, only TCPOBOP in Set B has increased the expression of two isoforms (MUP1 and 6). Our findings showed that the expression of MUP, normally involved in binding and excretion of pheromones, have drug- and sex-specific differences. The mechanism and significance of MUP up-regulation are ambiguous. Therefore, the impact of each therapeutic agent on MUP and xenobiotic enzymes will be discussed.
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Kassahun, Kelem. "Mechanistic studies of valproic acid hepatotoxicity : identification and characterization of thiol conjugates". Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30831.
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The severe hepatotoxicity of the antiepileptic drug valproic acid (VPA) is believed to be mediated through chemically reactive metabolites. The monounsaturated metabolite 4-ene VPA is steatogenic in the rat, and in a similar fashion to the hepatotoxin 4-pentenoic acid, is thought to be oxidized by mitochondria to a highly reactive α,β-unsaturated ketone, 3-keto-4-ene VPA. The tripeptide thiol, glutathione (GSH), is known to react with a variety of electrophilic compounds that have the potential to interact with cellular macromolecules. The identification and structural characterization of GSH conjugates provides a means of identifying short-lived unstable electrophiles and thus an insight into the mechanisms of toxicity. This thesis describes the synthesis and characterization of thiol conjugates of reactive metabolites derived from the in vivo metabolism of VPA, 4-ene VPA, (E)-2,4-diene VPA, and 4-pentenoic acid.
A negative ion chemical ionization gas chromatographic/mass spectrometric (NICI/GC/MS) method for the determination of VPA and 14 of its metabolites in a single chromatographic run was developed. A combination of pentafluorobenzyl and trimethylsilyl derivatization resulted in the [M-181]̄̄̄ ̄anion as the base peak for all the metabolites measured. When these ions were monitored sensitivities in the low picogram range were achieved. The VPA metabolite profile was determined in pediatric patients on VPA monotherapy and on combined therapy with either carbamazepine or clobazam. 4-Ene- and (E)-2,4-diene-VPA were found to be minor metabolites with serum levels below 1% that of VPA. In patients on combined therapy with carbamazepine, the ω and ω-l pathways of VPA metabolism were induced, while products of β-oxidation were significantly decreased. Polytherapy had no significant effect on the serum levels of 4-ene- or (E)-2,4-diene-VPA.
Rats were dosed intraperitoneally with 100 mg/kg of the sodium salts of VPA, 4-ene-, (E)-2,4-diene-VPA, 4-pentenoic or (E)-2,4-pentadienoic acids. Methylated bile extracts were analyzed by high pressure liquid chromatography and liquid chromatography/tandem mass spectrometry (LC/MS/MS) for GSH conjugates while urine samples were analyzed by GC/MS and LC/MS for N-acetylcysteine (NAC) conjugates and other metabolites. The GSH conjugate of (E)-2,4-diene VPA was detected in the bile of rats treated with 4-ene- and (E)-2,4-diene-VPA. The NAC conjugate was a major urinary metabolite of rats given (E)-2,4-diene VPA and was a prominent urinary metabolite of those animals given 4-ene VPA. The structures of these metabolites were confirmed by comparing GC/MS or LC/MS properties of the isolated metabolites to those of synthetic standards.
The GSH and NAC conjugates of (E)-2,4-diene VPA were chemically synthesized and their structures established to be (E)-5-(glutathion-S-yl)-3-ene VPA and (E)-5-(N-acetylcystein-S-yl)-3-ene VPA by nuclear magnetic resonance spectroscopy and mass spectrometry. In contrast to the very slow reaction of the free acid of (E)-2,4-diene VPA with GSH, the methyl ester reacted rapidly with GSH to yield the adduct. In vivo it appears the diene forms an intermediate with enhanced electrophilic reactivity to GSH as indicated by the facile reaction of the diene with GSH in vivo (about 40% of the (E)-2,4-diene VPA administered to rats was excreted as the NAC conjugate in 24 hr). In rats treated with 4-pentenoic and/or (E)-2,4-pentadienoic acids the following conjugates were identified and characterized by synthesis: GSH and cysteine conjugates of 3-oxo-4-pentenoic acid, GSH and NAC conjugates of (E)-2,4-pentadienoic acid, and the NAC conjugate of acrylic acid. The results thus provided the first direct biochemical evidence for the in vivo formation of the metabolite of 4-pentenoic acid considered responsible for the irreversible inhibition of fatty acid metabolism. The results also revealed basic differences between the mitochondrial metabolism of 4-ene VPA and 4-pentenoic acid.
The 3-keto-4-ene VPA and its GSH and NAC conjugates were synthesized in order to facilitate the in vivo identification of these compounds following the administration of VPA, 4-ene-, or (E)-2,4-diene-VPA to rats. However, neither the 3-keto-4-ene VPA nor its thiol derivatives were evident in any of the treatments.
The NAC conjugate of (E)-2,4-diene VPA was also found to be a metabolite of VPA in patients. The level of the conjugate appeared to be higher in two patients who recovered from VPA-induced liver toxicity. The characterization of GSH and NAC (in humans and rats) conjugates of (E)-2,4-diene VPA suggests that VPA is metabolized to a chemically reactive intermediate that may contribute to the hepatotoxicity of the drug.Pharmaceutical Sciences, Faculty of
Graduate
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Rodgers, Amie D. Rusyn Ivan. "Modeling adverse liver effects of drugs using kNN QSAR method". Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2009. http://dc.lib.unc.edu/u?/etd,2463.
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Thesis (M.S.)--University of North Carolina at Chapel Hill, 2009.Title from electronic title page (viewed Sep. 3, 2009). "... in partial fulfillment of the requirements for the degree of Masters of Sciences in the School of Medicine Toxicology." Discipline: Toxicology; Department/School: Medicine.
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Stevens, Jeffrey Charles 1963. "Selective inactivation of four rat liver microsomal androstenedione hydroxylases by chloramphenicol analogs". Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276700.
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The steroid androstenedione has been shown to be a valuable tool for the study of selective inactivation of rat liver cytochrome P-450 isozymes. The validity of this method was investigated using microsomes, purified cytochromes P-450, cytochrome P-450 antibodies, and the mechanism-based inactivator chloramphenicol. Enzyme inactivation and antibody inhibition studies show that microsomes from phenobarbital- and non-phenobarbital-treated rats are needed to accurately monitor the inactivation of the major phenobarbital-inducible P-450 isozyme (PB-B) and of the major constitutive androstenedione 16-alpha hydroxylase (UT-A). Enzyme inactivation studies showed that the antibiotic chloramphenicol caused different rates of NADPH-dependent enzyme inactivation among four androstenedione hydroxylases (16-beta > 6-beta > 16-alpha > 7-alpha). The results with twelve chloramphenicol analogs show that their selectivity as cytochrome P-450 inactivators is dependent upon at least three structural features: (1) the number of halogen atoms, (2) the presence of a para-nitro group on the phenyl ring, and (3) substitutions on the ethyl side chain.
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Abdelhadi, Mohamed Mohamed. "Posttransplantation bone disease : the effect of immunosuppressive drugs on bone: clinical and experimental studies /". Stockholm, 2002. http://diss.kib.ki.se/2002/91-7349-384-8/.
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Siebert, Gerhard A. "Disposition pharmacokinetics and effects of solutes and drugs in perfused organ systems /". [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18644.pdf.
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Nicholls-Grzemski, Felicity April. "The effect of short-term pretreatment with peroxisome proliferators on the acute toxicity of various toxicants, including paracetamol /". Title page, table of contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phn6158.pdf.
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Vaino, Andrew Rein. "Synthesis of agents for the targeting of drugs to the human liver and elucidation of the reverse anomeric effect". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ31959.pdf.
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Weng, Yu-I. "Acute and chronic ethanol effects on liver p42/44 mitogen activated protein kinase". free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3036867.
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Pittaya, Kanchanapakonchai Amnuay Thithapandha. "Effects of vitamin B6 on CC14 toxicities in rats /". abstract, 1986. http://mulinet3.li.mahidol.ac.th/thesis/2529/29E-Pittaya-K.pdf.
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Allen, Portia SueAnn. "The effect of drugs and nutraceuticals on the prevention and treatment of non-alcoholic fatty liver disease using rats as a model for humans". [Ames, Iowa : Iowa State University], 2010. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1476270.
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Plumb, Sarah. "The art of addiction : a phenomenological study of the lived experiences of cocaine dependents". Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/902.
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Addiction is a complex social phenomenon resulting from psychological and physiological dependence. The aim of the study was to create a clinical impression of the lived experiences of cocaine dependents. A transcendental phenomenological approach was used to elicit the essence of addiction as experienced by the participants. Theoretical sampling ensured relevant participants were selected through haphazard sampling procedures. Data was collected through the use of biographical questionnaires and individual, semi-structured interviews with three cocaine dependents. Data was processed according to the four phenomenological principles epoche, phenomenological reduction, imaginative variation and synthesis using Tesch’s eight steps. The essence of cocaine dependency is contained in the psychological experiences of the drug which define and perpetuate that addiction. The psychological addiction develops prior to physical dependence resulting in an entrenched addiction before treatment is sought by the cocaine dependents.
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Gronert, Álvarez Anna Christina [Verfasser], i Hans-Heinrich [Akademischer Betreuer] Wedemeyer. "Regulatory T cells in liver transplantation : phenotypical characterisation and effects of immunosuppressive drugs / Anna Christina Gronert Álvarez. Klinik für Gastroenterologie, Hepatologie und Endokrinologie der Medizinischen Hochschule Hannover. Betreuer: Hans-Heinrich Wedemeyer". Hannover : Bibliothek der Medizinischen Hochschule Hannover, 2014. http://d-nb.info/1050008200/34.
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Vivas, Ana Paula Molina. "Avaliação de manifestações bucais em pacientes pediátricos submetidos ao transplante hepático". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/23/23141/tde-13092012-112810/.
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Introdução. O transplante hepático se tornou a principal opção terapêutica para o tratamento de várias doenças hepáticas. Subsequentemente ao transplante, é necessária a administração de terapia imunossupressora para evitar rejeição ao órgão transplantado. A avaliação odontológica é fundamental para eliminação ou prevenção do surgimento de focos infecciosos. Além disso, faz-se necessário o acompanhamento dos efeitos colaterais em cavidade bucal relacionados ao uso de drogas imunossupressoras. Objetivo. Avaliar as condições odontológicas previamente ao transplante hepático e identificar as alterações bucais apresentadas após o transplante hepático. Pacientes e métodos. Foi realizado estudo retrospectivo de 265 pacientes pediátricos submetidos ao transplante hepático no Hospital A.C. Camargo, São Paulo-SP, entre janeiro de 2002 e dezembro de 2009. As informações clínicas como idade, gênero, diagnóstico da doença hepática, data do transplante, terapia imunossupressora (tipo, dose e duração), tratamento odontológico e a presença de alterações bucais pós-transplante foram coletadas dos prontuários médicos. Análise estatística foi realizada buscando estabelecer informações relevantes quanto aos riscos e possíveis fatores preditivos para o desenvolvimento de manifestações bucais. Resultados. A idade ao transplante hepático variou de 3,5 a 210,7 meses, tendo uma mediana de 15,5 meses. Dos 265 pacientes, 150 pacientes (56,6%) eram do gênero feminino e 165 (62,3%) eram leucodermas. Dentre as doenças de base, a atresia de vias biliares foi a mais frequente, acometendo 170 (64,1%) pacientes. Um total de 73 pacientes foi avaliado pelo Departamento de Estomatologia previamente ao transplante, e destes, 34 (46,6%) apresentaram cárie. Quanto à presença de pigmentação dentária por bilirrubina, 172 pacientes foram avaliados e destes, 100 (58,1%) apresentaram pigmentação. Em relação à presença de hipoplasia do esmalte dentário, a alteração foi observada em 56 (34,4%) de 163 pacientes. Interessantemente, dos 100 pacientes com pigmentação dentária por bilirrubina, 97 apresentavam doenças colestáticas (p<0,001). Quanto aos casos de hipoplasia do esmalte, 52 (92,9%) pertenciam ao grupo de doenças colestáticas (p<0,001). Diversas alterações em mucosa bucal foram encontradas após o transplante, sendo que 135 pacientes apresentaram alguma complicação. Dos 265 pacientes estudados, o principal problema encontrado foi infecção pelo vírus herpes simples, em 48 pacientes, sendo que 66,7% dos casos ocorreram a partir de 12 meses após o transplante. A segunda doença infecciosa mais comum em cavidade oral foi a candidose, observada em 39 pacientes e 61,5% dos casos ocorreram durante o primeiro semestre pós-transplante. Importantes alterações bucais foram encontradas em pacientes em uso de tacrolimus, como a hipertrofia de papilas linguais, ressecamento labial, edema labial, fissuras labiais, fissuras linguais, queilite angular, mucosa com aspecto de pedra de calçamento e língua despapilada, observadas em 45, 39, 39, 38, 27, 11 e 6 pacientes, respectivamente. A hiperplasia gengival medicamentosa foi observada em 13 pacientes, sendo que 8 estavam em uso de ciclosporina e todos os outros usavam além do tacrolimus, drogas bloqueadoras de canais de cálcio. A complicação que ocorreu mais precocemente nos pacientes após o transplante foi a doença linfoproliferativa, em média 5,2 meses após o transplante. Conclusões. O índice de cáries foi elevado refletindo as precárias condições de saúde bucal desses pacientes. A pigmentação por bilirrubina e a hipoplasia do esmalte são alterações dentárias associadas a doenças colestáticas, embora possam ocorrer em pacientes portadores de doenças não colestáticas que apresentem períodos de colestase. As lesões orais infecciosas mais frequentes foram lesões pelo vírus herpes simples e a candidose. A hiperplasia gengival medicamentosa está relacionada ao uso de ciclosporina e de bloqueadores de canais de cálcio, sendo que o tacrolimus não parece induzir o efeito. Alterações bucais como hipertrofia de papilas linguais, fissuras linguais, língua despapilada, ressecamento, edema e fissuras labiais; queilite angular e mucosa oral com aspecto de pedra de calçamento foram encontradas em pacientes em uso de tacrolimus e ocorreram normalmente 2 anos após o transplante.Introduction. Liver transplantation has become the main therapeutic option for the treatment of various liver diseases. Subsequent to transplantation, it is necessary to administer immunosuppressive treatment to avoid rejection of the graft. A dental evaluation is critical to eliminate or prevent the emergence of infectious foci. Moreover, it is necessary to monitor the side effects in the oral cavity related to the use of immunosuppressive drugs. Objectives. To evaluate the dental conditions prior to liver transplantation and to identify oral abnormalities presented after liver transplantation. Pacients and methods. A retrospective study of 265 pediatric patients who underwent liver transplantation at Hospital A.C. Camargo, São Paulo-SP, between January 2002 and December 2009 was performed. Clinical information such as age, gender, diagnosis of liver disease, date of transplantation, immunosuppressive therapy (type, dose and duration), dental treatment and oral changes after transplantation were collected from medical records. Statistical analysis was performed in order to establish relevant information about the risks and possible predictive factors for the development of oral manifestations. Results. The age at liver transplantation ranged from 3.5 to 210.7 months, with a median of 15.5 months. Of the 265 patients, 150 patients (56.6%) were female and 165 (62.3%) were Caucasian. Among the diseases, biliary atresia was the most frequent, with 170 (64.1%) patients. A total of 73 patients were evaluated by the Department of Stomatology prior to transplantation, and 34 (46.6%) children presented caries. Regarding the presence of tooth pigmentation caused by bilirubin, 172 patients were evaluated and out of these, 100 (58.1%) had pigmentation. Regarding the presence of enamel hypoplasia, the change was observed in 56 (34.4%) of 163 patients. Interestingly, of the 100 patients with bilirubin pigmented teeth, 97 had cholestatic diseases (p<0.001). Of the cases of enamel hypoplasia, 52 (92.9%) belonged to the group of cholestatic diseases (p<0.001). Several changes in the oral mucosa were found after transplantation, whereas 135 patients had some complication. Of the 265 patients studied, the main problem was herpes simplex virus infection, found in 48 patients and 66.7% of cases occurred after 12 months from transplantation. The second most common infectious disease was oral candidiasis, observed in 39 patients and 61.5% of cases occurred during the first six months post-transplant. Important oral abnormalities were found in patients using tacrolimus such as the hypertrophy of the lingual papillae, dry lips, swollen lips, fissured lips, fissured tongue, angular cheilitis, cobblestoning and loss of tongue papillae, observed in 45, 39, 39, 38, 27, 11 and 6 patients respectively. The drug-induced gingival overgrowth was observed in 13 patients, and 8 of them were taking cyclosporine, while all others were using tacrolimus in addition to calcium channel blockers. The post-transplant complication that occurred earlier in patients was lymphoproliferative disease, on average 5.2 months after transplantation. Conclusions. The rate of caries was high, reflecting poor oral health status of these patients. The bilirubin pigmentation of teeth and enamel hypoplasia are abnormalities associated with cholestatic diseases, although they may occur in patients with non-cholestatic diseases that present periods of cholestasis. The most common oral infectious lesions were caused by herpes simplex virus and candidiasis. The drug-induced gingival overgrowth is associated with the use of cyclosporin and calcium channel blockers, while tacrolimus does not appear to induce this effect. Oral alterations such as hypertrophy of the lingual papillae, fissured tongue, loss of tongue papillae, dry, swollen and fissured lips; angular cheilitis and cobblestoning were found in patients using tacrolimus and usually occured after 2 years from transplantation.
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Mets, Berend. "Lignocaine extraction ratio and clearance as an indicator of hypoxic hepatic injury : a study using the in situ and the isolated perfused pig liver". Doctoral thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/27152.
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The metabolism of lignocaine to monoethylglycinexylidide has been found useful as an indicator of hepatic function in association with liver transplantation. It has been postulated that this might be due to the common effect of hypoxic damage on liver function and lignocaine metabolism. The aim of this work was to establish whether hepatic lignocaine elimination was impaired by hypoxia and whether lignocaine extraction ratio and clearance could be used as an indicator of hepatic function. This was studied using the isolated pig liver perfused via the hepatic artery and portal vein. To establish whether the pig liver could be used as a possible human model for this investigation and whether lignocaine had any detrimental effects on liver function and blood flow in vivo, hepatic lignocaine elimination and the effects of lignocaine administration on hepatic function and blood flow were studied in the anaesthetized pig, surgically prepared to allow sampling across the liver and direct hepatic blood flow measurement. Hepatic lignocaine elimination was then studied in the isolated perfused liver to determine whether this was similar to that found in vivo. The definitive studies required preliminary investigations not available from the literature to determine the feasibility of comparing in vivo and ex vivo hepatic function using the same liver. In addition, by studying the decay of lignocaine after bolus dose administration the necessary pharmacokinetic parameters to achieve similar constant hepatic affluent lignocaine concentrations in vivo and in the isolated preparation could be determined. The preliminary investigations showed that a sequential experiment using the same liver to compare in vivo and ex vivo function was inappropriate as the energy state of isolated perfused livers previously studied in vivo was significantly different from that in livers perfused immediately. The decay of lignocaine after a bolus dose in vivo and ex vivo could be described by a two-compartment open model and in both preparations the derived pharmacokinetic parameters from this analysis were used to achieve similar constant hepatic affluent concentrations over the study period used to determine hepatic lignocaine elimination. Lignocaine extraction ratio by the in situ pig liver was similar to that reported in man and together with hepatic clearance and intrinsic clearance was similar to that determined in the isolated state when different livers were used for this comparison. There was no detrimental effect of lignocaine administration on hepatic function and blood flow In vivo. Lignocaine extraction ratio and clearance and monoethylglycinexylidide formation were significantly impaired in livers subjected to hypoxia. Lignocaine elimination correlated strongly with hepatic cellular ATP, energy charge and ATP/ ADP ratio as well as with hepatic potassium release but less strongly with aspartate aminotransferase release when this relationship was tested using the combined data from hypoxic and normoxic livers ex vivo. These correlations were positive for hepatic adenine nucleotide status and negative for hepatic potassium and aspartate aminotransferase release. Neither hepatic alanine aminotransferase release nor lactate utilization were significantly affected by hypoxia. Lignocaine extraction ratio, hepatic oxygen consumption, ATP content, bile flow and potassium release were shown to be equivalent, more highly sensitive, and earlier indicators of hypoxic hepatic injury than hepatic aspartate aminotransferase release in the isolated perfused pig liver.
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Hauton, David. "The effects of diet on drug metabolism in the rat". Thesis, University of Surrey, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.484200.
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Tacon, Geoffrey Reginald Russell. "Mathematical modelling of liver kinetics /". [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19399.pdf.
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Nielsch, A. S. "Effects of prostaglandins and prostaglandin synthetase inhibitors on liver toxicity". Thesis, University of Aberdeen, 1987. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU499301.
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A total of 22 non-steroidal anti-inflammatory drugs and derivatives were added to microsomes to study the denaturation of cytochrome P-450 to cytochrome P-420 in the absence of an NADPH-generating system. There was a highly significant correlation among the different compounds between the extent of denaturation of cytochrome P-450 and their surfactant potency. Endotoxin administration to rats caused a maximum decrease in hepatic microsomal enzymes after 24 hours. Significant decreases in cytochrome P-450 (40%), cytochrome b5 levels (22%), aminopyrine N-demethylase (31%) and biphenyl 4-hydroxylase (54%) activities were obtained. Concomitant intravenous injection of 16,16-DMPG F2 and 16,16-DMPG E2 prevented some of the endotoxin-induced changes in hepatic microsomal enzymes. Three days treatment with cocaine was required to obtain hepatic damage in mice. Decreases in cytochrome P-450 content (41%), aminopyrine N-demethylase (31%) and FAD-monooxygenase (35%) activities were obtained, when compared to saline treated mice. The serum enzyme activities were markedly increased (SGOT 13-fold and SOCT 44-fold). Histological changes in form of centrilobular necrosis and fatty changes were present. Repeated subcutaneous administration of iloprost or synthetic prostaglandins just before cocaine prevented some of the hepatic lesions. Iloprost was found to be a better hepatoprotective agent than synthetic prostaglandins against the cocaine mediated liver toxicity. Carbon tetrachloride administration to mice produced similar lesions to those obtained with cocaine. Administration of iloprost prevented some of the lesions caused by carbon tetrachloride, giving a partial protection to the carbon tetrachloride-induced decrease in cytochrome P-450 and the increase in SGOT. Iloprost also partially prevented the carbon tetrachloride mediated centrilobular necrosis.
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Bradshaw, Jennifer Jean. "Isoflurane : interaction with hepatic microsomal enzymes". Doctoral thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/27138.
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lsoflurane interacts with cytochrome P-450 in rat and human hepatic microsomes and the Δ6- and Δ5-desaturases in rat hepatic microsomes. The interaction of isoflurane with cytochrome P-450 results in its metabolism to fluoride ion and organofluorine metabolites. The cytochrome P-450 isozymes catalysing the defluorination of isoflurane were assessed in hepatic microsomes from phenobarbital-, β-naphthoflavone- and pregnenolone-16α-carbonitrilepretreated and untreated rats. One or more of the cytochrome P-450 isozymes induced by phenobarbital and pregnenolone-16α-carbonitrile appear to defluorinate isoflurane, but those induced by β-naphthoflavone do not. From a comparison of the extent of defluorination of isoflurane in hepatic microsomes from phenobarbital- and pregnenolone-16α-carbonitrile-pretreated rats, and their Kₘ and Vₘₐₓ values, it appears that isoflurane is defluorinated by one or more isozymes induced by both phenobarbital and pregnenolone-16α-carbonitrile. The major isozyme is probably cytochrome P-450PCN1. The metabolites of isoflurane were identified in human and phenobarbital-induced rat hepatic microsomes. In microsomes from phenobarbital-pretreated rats, isoflurane is metabolised to fluoride ion and trifluoroacetaldehyde; trifluoroacetic acid is not produced in measureable amounts. The trifluoroacetaldehyde produced binds to microsomal constituents. In human hepatic microsomes, the organofluorine metabolite is identified as trifluoroacetic acid. It is proposed that isoflurane is metabolised by different pathways in human and phenobarbital-induced rat hepatic microsomes. The interaction of isoflurane with the cyanide-sensitive factors was assessed by several criteria. Firstly, using the reoxidation of cytochrome b₅ as an index of fatty acid desaturase activity, isoflurane appears to interact with the Δ6- and/or Δ5-desaturases, but not the Δ9-desaturase. Secondly, these results were confirmed and clarified by the use of direct assays to measure the fatty acid desaturase activity. Using the direct assay, we confirmed that isoflurane did not inhibit the Δ9-desaturase and inhibited Δ6-desaturation of linoleic acid, but not the Δ6-desaturation of α-linolenic acid. The inhibition of the Δ6-desaturation of linoleic acid occurred at low millimolar concentrations of isoflurane. lsoflurane inhibits the Δ5-desaturation of eicosa-8, 11, 14-trienoic acid to a small extent which is only apparent at much higher concentrations of isoflurane than that which inhibits the Δ6-desaturase. Further studies focussed on measurement of the activity of Δ6-desaturase in order to attempt to study the kinetics of the inhibition of the Δ6-desaturase by isoflurane: Δ6-desaturase activity was assessed using hepatic microsomes as the source of the enzyme and linoleic acid as substrate precursor. In the course of these studies, we identified a number of factors that affected the apparent activity of the Δ6-desaturase in hepatic microsomes. These included significant levels of endogenous substrate and competing reactions in the hepatic microsomes. Endogenous substrate levels were quantified and corrected for. We then resorted to computer modelling to extract the kinetics of the Δ6-desaturase free of contributions from acyl-CoA synthetase and lysophospholipid acyltransferase, as well as enzyme decay. The kinetics of isoflurane inhibition of the Δ6-desaturase were then superimposed and studied by computer modelling.
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Jokinen, Mika. "Effects of drug interactions and liver disease on the pharmacokinetics of ropivacaine". Helsinki : University of Helsinki, 2003. http://ethesis.helsinki.fi/julkaisut/laa/kliin/vk/jokinen/.
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Eng, Heather Sui-Fong. "Evaluating the use of cryopreserved hepatocytes for the prediction of in vivo hepatic clearance /". See Full Text at OhioLINK ETD Center (Requires Adobe Acrobat Reader for viewing), 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1091638312.
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Thesis (M.S.P.)--University of Toledo, 2004.Typescript. "A thesis [submitted] as partial fulfillment of the requirements of the Master of Science degree in Pharmaceutical Sciences." Bibliography: leaves 64-68.
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Chang, Ping. "Quantitative evaluation of hepatic morphological alterations and pharmacokinetic changes of cationic drugs in fibrosis-inducing hepatic diseases /". St. Lucia, Qld, 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16767.pdf.
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Anwar, Khurshid. "Role of apoptosis (programmed cell death) in acute liver failure". Thesis, University of Surrey, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370058.
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Yildirim, Pinar. "Acquisition Of Liver Specific Parasites-bacteria-drugs-diseases-genes Knowledge From Medline". Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613143/index.pdf.
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Biomedical literature such as MEDLINE articles are rich resources for discovering and tracking disease and drug knowledge. For example, information regarding the drugs that are used with a particular disease or the changes in drug usage over time is valulable. However, this information is buried in thousands of MEDLINE articles. Acquiring knowledge from these articles requires complex processes depending on the biomedical text mining techniques. Today, parasitic and bacterial diseases affect hundreds of millions of people worldwide. They result in significant mortality and devastating social and economic consequences. There are many control and eradication programs conducted in the world. Also, many drugs are developed for diseases caused from parasites and bacteria. In this study, research was conducted of parasites (bacteria affecting the liver) and treatment drugs were tested. Also, relationships between these diseases and genes, along with parasites and bacteria were searched through data and biomedical text mining techniques. This study reveals that the treatment of parasites and bacteria seems to be stable over the last four decades. The methodology introduced in this study also presents a reference model to acquire medical knowledge from the literature.
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Cook, Andrew T. "The effect of accelerated aging on peelable medical products seals /". Online version of thesis, 1994. http://hdl.handle.net/1850/11980.
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Weise-Kelly, Lorraine Ann. "Drug-induced ataxia : effect of the self-administration contingency /". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0030/NQ66245.pdf.
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McLure, James Alexander, i james mclure@flinders edu au. "Physicochemical determinants of the non-specific binding of drugs to human liver microsomes". Flinders University. Medicine, 2008. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20081102.165952.
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Accurate determination of the in vitro kinetic parameters Km (Michaelis constant) and Ki (inhibition constant) is critical for the quantitative prediction of in vivo drug clearance and the magnitude of inhibitory drug interactions. A cause of inaccuracy in vitro arises from the assumption that all drug added to an incubation mixture is available for metabolism or inhibition. Many drugs bind non-specifically to the membrane of the in vitro enzyme source.
The aims of this thesis were to: 1) investigate the comparative importance of lipophilicity (as log P), and pKa as determinants of the non-specific binding of drugs to human liver microsomes; 2) develop and validate an ANS fluorescence technique for measuring the non-specific binding of drugs to human liver microsomes; 3) characterise the non-specific binding of a large dataset of physicochemically diverse drugs using the ANS fluorescence procedure; 4) evaluate relationships between selected physicochemical characteristics and the extent of non-specific binding of drugs to human liver microsomes and; 5) computationally model the non-specific binding of drugs to discriminate between high binding (fu(mic) less than 0.5) and low binding (fu(mic) greater than 0.5) drugs.
The comparative binding of the basic drugs atenolol (log P = 0.1; fu(mic) = 1.00), of propranolol (log P = 3.1; fu(mic) = 0.36 - 0.84), and imipramine (log P = 4.8; fu(mic) = 0.42 - 0.82) suggested that lipophilicity is a major determinant of non-specific binding. In contrast, the comparative binding of diazepam (pKa = 3.3; fu(mic) = 0.69 - 0.80), a neutral compound; and the bases propranolol (pKa = 9.5; fu(mic) = 0.36 - 0.84) and lignocaine (pKa = 9.5; fu(mic) = 0.98), indicated that pKa was not a determinant of the extent of non-specific binding. The non-binding of lignocaine, a relatively lipophilic base, was unexpected and confirmed by the non-binding of the structurally related compounds bupivacaine and ropivacaine. These results implicated physicochemical characteristics other than lipophilicity and charge as important for the non-specific binding of drugs to human liver microsomes.
An assay based on 1-anilinonaphthalene-8-sulfonate (ANS) fluorescence was developed using the seven drugs employed in the initial study. Non-specific binding data from equilibrium dialysis and the ANS fluorescence methods were compared and a linear correlation (r2 = 0.92, p less than 0.01) was observed at drug concentrations of 100 and 200 micromolar. The approach was further validated by characterising the microsomal binding of nine compounds (bupropion, chloroquine, chlorpromazine, diflunisal, flufenamic acid, meclofenamic acid, mianserine, triflupromazine, and verapamil) using both binding methods (i.e. equilibrium dialysis and ANS fluorescence). A significant logarithmic relationship (r2 greater than or equal to 0.90) was demonstrated between fu(mic) and the modulus of ANS fluorescence for all drugs and for basic drugs alone at concentrations of 100 and 200 micromolar, while the acidic/neutral drugs showed a significant linear relationship (r2 greater than or equal to 0.84) at these two concentrations (p less than 0.01). The non binding of bupropion provided further evidence that physicochemical properties other than log P and charge were important for non-specific binding of drugs to human liver microsomes.
The ANS fluorescence technique was then used to characterise the non-specific binding of 88 physicochemically diverse compounds. In general, acids and neutrals bound to a low extent (fu(mic) greater than 0.5) whereas bases bound the full fu(mic) range (0.0001 to 1). Statistically significant relationships were observed between the non-specific binding of bases and log P, the number of hydrogen bond donors and hydrogen bond acceptors per molecule, and molecular mass.
Preliminary in silico modeling of the dataset generated by the ANS fluorescence technique, using the program ROCS, provided discrimination of all but one (itraconazole) of the high binding bases. However, there were 14 false positives, resulting in low overall prediction accuracy.
Taken together, the studies conducted in this thesis provide important insights into the physicochemical factors that determine the non-specific binding of drugs to human liver microsomes.
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Chang, Robert Chao Sun Wei. "Biofabrication of three-dimensional liver cell-embedded tissue constructs for in vitro drug metabolism models /". Philadelphia, Pa. : Drexel University, 2009. http://hdl.handle.net/1860/3069.
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Bai, Shuang. "Effect of immunosuppressive agents on drug metabolism in rats". Thesis, Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3008270.
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Hammann, Felix. "Prediction of transport, pharmacokinetics, and effect of drugs /". Basel : [s.n.], 2009. http://edoc.unibas.ch/diss/DissB_8905.
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Baser, Deniz Fulya. "Characterization And Modulation By Drugs And Other Effectors Of Bovine Liver Microsomal Flavin Monooxygenase (fmo)". Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12604749/index.pdf.
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The flavin-containing monooxygenases (FMOE.C.1.14.13.8) are microsomal NADPH and oxygen-dependent flavoprotein enzymes that catalyze the oxidation of a wide variety of xenobiotics, including drugs and environmental toxicants. Nucleophiles containing nitrogen, sulfur, phosphorus and selenium heteroatoms are the substrates of FMO. Bovine liver microsomal FMO enzyme activity was characterized using methimazole as substrate, which is a highly specific substrate for FMO. From 12 different bovine liver samples, microsomes were prepared and the average specific activity of bovine liver microsomal FMO was found to be 2.37 &
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0.30 nmol/min/mg (Mean &
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SE, n=12). The rate of reaction was linear up to 0.5 mg of bovine liver microsomal protein. The maximum FMO enzyme activity was detected at 37 &
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C and at pH 8.0. Effects of detergents
Triton X-100 and Emulgen 913, on FMO activity were determined and found that enzyme activity increased by the addition of either detergent at all concentrations (0.1%-1.0%). The apparent Vmax and Km values of bovine liver microsomal FMO for methimazole substrate were found as 1.23 nmol/min/mg and 0.11 mM, respectively. Thermostability of bovine liver microsomal FMO was studied at four different temperatures
24 &
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C, 37 &
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C, 50 &
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C and 65 &
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C. The incubation time required for the complete loss of enzyme activity was 5 minutes at 65 &
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C, 10 minutes at 50 &
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C and 6.5 hours at 37 &
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C. 68 % of the activity was still detectable at the end of 53 hours at 24 &
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C. Bovine liver microsomal activity towards two drug substrates, imipramine and chlorpromazine, was also determined and found to be 3.73 and 3.75 nmol NADPH oxidized/min/mg, respectively. Effects of two drug substrates, imipramine and chlorpromazine, on bovine liver microsomal FMO-catalyzed methimazole oxidation activity was also studied and found that they inhibit FMO activity at all concentrations studied. Modulation of bovine liver microsomal FMO activity was studied using three different heavy metal ions
Ni+2, Cd+2 and Hg+2. At all other concentrations studied for each heavy metal ion and at all substrate methimazole concentrations (0.1, 0.2, 0.5, 1.0 mM), FMO-catalyzed methimazole oxidation activity decreased compared to control activity. KI values for Ni+2, Cd+2 and Hg+2 were found to be 0.5 mM, 0.085 mM, 4.6 &
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M, respectively. From the Dixon plot, the pattern of inhibition for three heavy metal ions was observed to be noncompetitive.
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Owoseni, Seun Emmanuel. "The Study of Alcoholic Liver Diseases". Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etd/3493.
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Excessive alcohol consumption is the primary contributing factor in the development of alcoholic liver diseases (ALD). Nicotine contained in tobacco is a major addictive alkaloid, which enhances the effects of ALDs. The major enzyme involved in nicotine metabolism is cytochrome P450 2A5 (CYP2A5) which is produced in the liver. Alcohol can stimulate the CYP2A5 enzyme. We utilized cyp2a5-/- knockout mice in this research to examine the effects of CYP2A5.
The cyp2a5-/- mice and wild-type (WT) mice were fed liquid ethanol diet with or without nicotine to induce ALD. Nicotine enhancing effects on ALD were observed in WT mice but not in cyp2a5-/- mice. Oxidative stress was stimulated by alcohol and further increased by nicotine in WT mice but not in cyp2a5-/-mice. Microsomal ROS production during microsomal metabolism of nicotine was increased in WT mice but not in cyp2a5-/-mice. These results suggest that nicotine enhances ALD is CYP2A5 dependent.
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Mazza, Rosangela Passos de Jesus. "Influência da infusão parenteral de aminoácidos sobre a expressão gênica de fatores de crescimento de timidina quinase no remanescente hepático de ratos desnutridos". Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/5/5160/tde-15102014-090956/.
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A Glutamina (Gln) melhora a regeneração hepática em ratos nutridos. Para avaliar o efeito molecular da Gln endovenosa no remanescente hepático, 52 ratos foram classificados em: 1. Nutridos com hepatectomia parcial (HP) e Gln (N-Gln=10) ou prolina (N-Pro=10); 2. Desnutridos com HP: (D-Gln=10) ou (D-Pro=10); 3. Nutridos e Desnutridos sem HP (N-Controle=6) e (D-Controle=6). Após 96 horas da HP os resultados foram: DNA = (D-Gln, D-Pro e D-Controle < N-Gln, N-Pro e N-controle), (N-Gln, N-Pro, D-Gln e D-Pro < N e D-Controle), (N-Gln > D-Gln); RNA= (N-Gln, N-Pro, D-Gln e D-Pro < N e D-Controle), (N-Gln > D-Gln e N-Pro). Não houve diferença nos genes transcritos (GT) para HGF, TGF-a e timidina kinase. Concluímos que: A desnutrição e HP reduzem DNA e RNA; A Gln não altera os GT estudados em ratos desnutridos 96 horas após HPGlutamine dipeptide (Gln) improve hepatic regeneration of nourished rats. To evaluate molecular effect of Gln on liver remnant 52 rats was classified into: 1. Nourished with partial hepatectomy (PH) and Gln (N-Gln=10) or proline (N-Pro=10); 2. Malnourished (MN) with PH: (MN-Gln=10) or (MN-Pro=10); 3. Nourished and Malnourished rat without PH (N-Control=6) and (MN-Control=6). Results: DNA = (MN-Gln, MN-Pro and MN-Control < N-Gln, N-Pro and N-control), (N-Gln, N-Pro, MN-Gln and MN-Pro < N and MN-Control), (N-Gln > MN-Gln); RNA= (N-Gln, N-Pro, MN-Gln and MN-Pro < N and MN-Control), (N-Gln > MN-Gln and N-Pro). There was no difference on transcript genes (TG) for HGF, TGF-a and thymidine kinase. Conclusions: Malnutrition and PH decrease hepatic DNA and RNA; Gln does not modify TG studied 96 hours after PH in MN rats
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McConnachie, Lisa A. "Effects of genotype and RNA expression on activity of cytochrome P450 2D6 : a highly polymorphic drug metabolizing enzyme /". Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/7973.
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Hoa, Nguyen Khanh. "Assessment of anti-diabetic effect of Vietnamese herbal drugs /". Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-585-2/.
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Elliott-Pearce, Ruth Ann. "The effect of drugs on isolated detrusor muscle contraction". Thesis, University of Leicester, 1996. http://hdl.handle.net/2381/34339.
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Detrusor instability is the commonest type of urinary incontinence in the elderly and is present in up to 50% of patients attending continence clinics. Treatment of this condition, aimed at reducing uncontrollable detrusor contractions, is at present unsatisfactory. For example, calcium antagonists are cliniclly disappointing and studies were carried out to investigate why they are ineffective. Rats were treated with nimodipine for 8 days or with a single dose. Treatment for 8 days had no effect on isolated detrasor contraction but a single dose reduced detrasor contractile response. It is propossed that chronic treatment with nimodipine caused an up-regulation of calcium channels as a compensatory mechanism. Oestrogens have been shown to have an inhibitory effect on detrusor muscle contraction after in vitro and in vivo treatment. In post-menopausal women with a uterus unopposed oestrogens should not be given, but progesterone has anti-oestrogenic actions. When rats were treated with oestrogen and progesterone for 8 days, there was no effect on rat detrasor contractile response. An anti-oestrogenic effect of progesterone has therefore been demonstrated in rat detrusor smooth muscle. Caffeine has been shown to increase detrasor pressme on bladder filling in patients with detrusor instability. The effect of low concentrations of caffeine on the contractile response of isolated human and rat detrusor muscle was therefore determined. Caffeine was found to have only a slight potentiating effect on isolated human and rat detruosr muscle contraction. The results in this thesis have important clinical imphcations for the treatment of detrusor instability. It may be more effective to administer calcium antagonists in an intermittent manner. Oestrogens are better given alone or with the lowest possible dose of progestogens. Caffeine would not be contraindicated in patients with detrusor instability.
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Dalal, Suntanu. "Amphetamine drugs potentiate morphine analgesia in the formalin test". Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=55488.
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There has been a great deal of research investigating drug combinations which can increase analgesia. A number of studies have been conducted with one particular combination--opioids combined with the amphetamine drugs. Despite the existing literature, this combination is rarely used in clinical practice. One purpose of this thesis is to review the literature pertaining to the opioid-amphetamine combination. Another purpose of this thesis is to investigate whether dextroamphetamine sulfate ($ circler$Dexedrine) can potentiate morphine sulfate analgesia in rats in the formalin test (Experiment 1). To investigate whether these results can be generalized to another psychostimulant, methylphenidate hydrochloride ($ circler$Ritalin) is used in Experiment 2. Methylphenidate has been chosen instead of another amphetamine drug because it is currently being used in clinical studies without supporting evidence from animal studies. The results of the two experiments indicate that low doses of d-amphetamine and methylphenidate can potentiate the analgesic effects of morphine.
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Tang, Chi-man Terence. "The effect of celecoxib on hepatocellular carcinoma". Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B35774393.
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Lui, Lik-hang Eric. "The effect of AMN107 on hepatocellular carcinoma". Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B39557248.
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Teran, Claudia. "Efficacy and Mechanism of Action of a Novel Class of Antic-Cancer Drugs". Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34412.
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The incidence of cancer worldwide has increased over the years, and gastrointestinal cancers (G.I.) are amongst the most common forms of cancer. Nevertheless, there is still no curative treatments for this group of tumors. Nucleoside analogues are widely used in cancer treatment. The prevailing compounds are Gemcitabine (used for pancreatic cancer and other carcinomas), 5-Fluorouracil (used in breast, colon, and other cancers), Cytarabine and Clofarabine (used in leukemias). Gemcitabine, the current standard of care for various forms of solid tumors, has a limited efficacy against pancreatic cancer. The objective of this project was the development of effective drugs against pancreatic cancer. We focused on a novel class of nucleoside analogues designed to bypass the most common cellular road blocks and resistance mechanisms. After an extensive screen for cell killing activity, two lead molecules were exclusively studied: LCB2151 and LCB2132. These two molecules showed high efficacy in killing human cancer cells from three different human G.I. cell lines: BxPC3 and Capan-2, two pancreatic cell lines representative of K-Ras positive and negative tumors, as well as the liver cell line HepG2. LCB2151 showed high efficacy in killing Gemcitabine-resistant cancer cells, and a low toxicity in normal cells. Interestingly, results show that these prodrugs can efficiently bypass key resistance mechanisms developed by cancer cells. The results obtained in this project are promising and could pave the way for a more effective treatment of pancreatic cancer.
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Xia, Ying. "Risk of Acute Liver Injury Associated with the Use of Orlistat: Cohort and Self-Controlled Case Series Studies Using the MarketScan® Commercial Claims Database". University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1490354985131296.
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Tannuri, Ana Cristina Aoun. "Modelos de regeneração hepática em animais em crescimento: estudos histológicos, moleculares e avaliação de efeitos de imunossupressores". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/5/5132/tde-19082007-113440/.
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INTRODUÇÃO: Transplantes parciais de fígado em crianças têm sido realizados com maior freqüência, enfatizando a importância do estudo da regeneração hepática, bem como dos efeitos de drogas imunossupressoras sobre a mesma. A regeneração do parênquima é o resultado do balanço entre multiplicação celular e apoptose, esta última definida como morte celular programada. Neste processo, estão envolvidas expressões de genes pró-apoptóticos (Bak e Bax) e anti-apoptóticos (Bcl-XL e Bcl-2). Dentre as proteínas relacionadas à proliferação hepatocitária, destaca-se a interleucina-6 (IL-6). Embora o modelo de ressecção de 70% da massa hepática de ratos adultos seja amplamente utilizado para estudos de regeneração, não há trabalhos com animais em crescimento. MÉTODOS: Na presente pesquisa, foi padronizado o modelo de hepatectomia parcial em ratos recém-nascidos e em recém-desmamados: realizou-se ligadura com fio de algodão do pedículo dos lobos esquerdo lateral, esquerdo medial e direito medial, seguida da ressecção do parênquima desses lobos. Os fígados remanescentes foram imediatamente pesados e comparados com os pesos dos fígados de animais controles. Para caracterização dos modelos de regeneração, 40 ratos recém-nascidos e 30 recém-desmamados foram submetidos à hepatectomia descrita e mortos nos dias subseqüentes (1, 2, 3, 4 e 7), e o fígado residual submetido a análises de peso e histologia convencional. A seguir, 36 animais (18 recém-nascidos e 18 recém-desmamados) foram divididos nos seguintes grupos: controle, cirurgia simulada e hepatectomia. Um dia após, utilizando métodos moleculares (técnica do RT-PCR), estudou-se a expressão do gene da IL-6, dos genes pró-apoptóticos e anti-apoptóticos nos fígados desses animais e, por meio de métodos imunoistoquímicos, analisou-se a presença de antígenos relacionados à proliferação celular (PCNA) e apoptose (TUNEL) em lâminas preparadas pela técnica do \"tissue microarray\". Em outros 36 ratos (18 recém-nascidos e 18 recém-desmamados), foram administradas drogas imunossupressoras (metilprednisolona, ciclosporina A ou tacrolimus, separadamente) no ato da hepatectomia, e o parênquima hepático remanescente submetido às mesmas análises moleculares e imunoistoquímicas, um dia após. RESULTADOS: A ressecção do parênquima hepático correspondeu a 70% da massa total do fígado. A mortalidade relacionada à hepatectomia nos animais recém-nascidos e recém-desmamados foi 30% e 0% respectivamente. Na análise histológica observou-se maior quantidade de mitoses em hepatócitos no terceiro dia nos recém-nascidos e no segundo dia nos recém-desmamados, com normalização da arquitetura do parênquima até o 7º dia e recuperação total do peso de ambos. No animal recém-nascido, notou-se intensa esteatose associada ao processo regenerativo. A hepatectomia provocou aumento na expressão do gene da IL-6 no fígado residual e diminuição da expressão dos genes pró-apoptóticos em ambos os modelos, além de aumento do anti-apoptótico Bcl-2 nos animais recém-desmamados. O estudo realizado sobre o efeito das drogas imunossupressoras mostrou resultados diferentes daqueles descritos em animais adultos, não havendo alteração no número de células em proliferação (PCNA positivas) ou apoptose (TUNEL positivas). As drogas não tiveram efeito sobre a expressão do gene da IL-6. Metilprednisolona e tacrolimus ocasionaram aumento da expressão do gene anti-apoptótico Bcl-2 em ambos os modelos; metilprednisolona e ciclosporina provocaram aumento na expressão do gene pró-apoptótico Bak nos ratos recém-nascidos. CONCLUSÕES: os modelos de regeneração hepática em ratos recém-nascidos e recém-desmamados foram exeqüíveis e adequados para a pesquisa; a hepatectomia promoveu estímulo da proliferação de hepatócitos com inibição da apoptose; as drogas imunossupressoras utilizadas não exerceram efeito sobre a proliferação de hepatócitos porém provocaram aumento da expressão de genes relacionados a apoptose.INTRODUCTION: Partial liver transplantation has been performed in children with increasing frequency, and this emphasizes the importance of the studies of hepatic regeneration and the effects of immunosuppressive drugs on this phenomenon. Liver regeneration is controlled by the balance between cell proliferation and apoptosis (defined as a programmed cell death that results from the expression of pro-apoptotic genes - Bax and Bak - and anti-apoptotic genes - Bcl-2 and Bcl-XL). Among proteins related to hepatocyte proliferation, interleukin-6 is an important one. Although the adult rat model of 70% hepatectomy has been widely utilized for studies of liver regeneration, there are no studies using growing animals. METHODS: In the current paper, two experimental models were created utilizing newborn and weaning rats: using a cotton thread, the vascular hilum and the hepatic vein were ligated and the left lateral, left medial and right medial lobes were resected. The remaining liver was immediately harvested and weighted to be compared to control livers. The animals were sacrificed on days 1, 2, 3, 4, and 7 after the operation, the remnant livers were weighted and harvested for histological examinations. Then, 36 animals (18 newborn and 18 weaning animals) were divided into the following groups: control, sham and hepatectomy. One day after, the expressions of IL-6 gene, pro-apoptotic and anti-apoptotic genes were studied in the remnant livers. Immunohistochemical stainings for cell antigens related to cell proliferation (PCNA) and apoptosis (TUNEL) were also performed utilizing tissue microarray sections. In another group of 36 animals (18 newborn and 18 weaning animals), immunosuppressive drugs were administered just after the hepatectomy (methylprednisolone, cyclosporine A or tacrolimus separately), and the remnant liver submitted to the same molecular and immunohistochemical studies. RESULTS: The resected liver corresponded to 70% of the total liver weight. The mortality rates after hepatectomy were 30% and 0% for newborn and weaning rats, respectively. The histological examinations showed a great number of mitoses of hepatocytes on the third day in newborns and on the second day in weaning rats, and normalization of histological aspects by 7 days after hepatectomy and weight recuperation. In the newborn group liver regeneration was related to an intense steatosis. Hepatectomy promoted an increase in the expression of IL-6 gene of the remnant liver, a decreased expression of pro-apoptotic genes in both models, and an increased expression of anti-apoptotic Bcl-2 gene in weaning rats. The study of the effects of immunosuppressants showed different results from those described in adult animals, with no alterations in the number of cells in proliferation (PCNA positive) and apoptosis (TUNEL positive). Drugs had no effect in expression of IL-6 gene. Methylprednisolone and tacrolimus promoted an increased expression of anti-apoptotic gene Bcl-2. In addition, methylprednisolone and cyclosporine promoted an increase in the expression of the pro-apoptotic gene Bak in newborn rats. CONCLUSIONS: The experimental models were feasible and adequate for the current investigations; hepatectomy stimulated hepatocyte proliferation and inhibited hepatic cells apoptosis; the utilized immunosuppressant drugs did not affect hepatocyte proliferation although an increased expression of apoptosis-related genes was verified.
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Smith, Cornel. "The effect of preserving liver tissue in formalin on the concentration of trace minerals in the liver". Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-08052005-101056/.
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Morrison, Roxanne. "The development of an in vitro system for the production of drug metabolites using microsomal enzymes from bovine liver". Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1007698.
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Drug metabolism is a specialised subset of xenobiotic metabolism, pertaining to the breakdown and elimination of pharmaceutical drugs. The enzymes involved in these pathways are the cytochrome P450 family of isozymes. Metabolism is an important factor in determining the pharmacological effects of drugs. The main aim of this study was to develop a system whereby the major metabolites of drugs can be produced in vitro. An in vitro system was developed and optimised using commercially prepared microsomes from rat liver and coumarin (by monitoring its conversion to 7-hydroxycoumarin) as a model. The optimum running conditions for the incubations were 50 μM coumarin, 50 μg protein/ml microsomes, 1 mM NADP⁺, 5 mM G6P and 1U/ml G6PDH incubated for 30 minutes at 38℃. The HPLC method for the detection of coumarin and 7-hydroxycoumarin was also validated with respect to linearity, reproducibility, precision, accuracy and lower limits of detection and quantification. The system developed was then tested using microsomes prepared from fresh bovine liver on these ten drugs of interest in doping control in horse racing: diazepam, nordiazepam, oxazepam, promazine, acepromazine, chlorpromazine, morphine, codeine, etoricoxib and lumiracoxib. The bovine liver microsomes were prepared using differential centrifugation and had activity on a par with the commercial preparations. This in vitro system metabolised the drugs and produced both phase I and II metabolites, similar to those observed in humans and horses in vivo. For example, the major metabolites of the benzodiazepine drug, diazepam, nordiazepam, temazepam and oxazepam as well as the glucuronidated phase II products were all found after incubations with the bovine liver microsomes. The metabolism of the drugs was also investigated in silico using the computational procedure, MetaSite. MetaSite was able to successfully predict known metabolites for most of the drugs studied. Differences were observed from the in vitro incubations and this is most likely due to MetaSite using only human cytochrome P450s for analysis.
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Lange, Jeremy David. "The effect of anti-malarial drugs on the pituitary gland". Thesis, University of Leeds, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238726.
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Figueiredo, João Daniel Amaral. "The effect of anticancer drugs prodiginines in PP1 in melanoma". Master's thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/6861.
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Mestrado em Biomedicina MolecularUm dos principais mecanismos reguladores da função celular é a fosforilação de proteínas. É de focar que a fosforilação anormal de proteínas-chave pode estar associada a várias patologias, incluindo o cancro. Embora já existam muitos estudos sobre cinases no cancro, o conhecimento sobre as fosfatases que antagonizam a acção das cinases é muito menos. A PP1, uma das principais proteínas fosfatase de serina/treonina expressa em todas as células eucarióticas, está envolvida em vários processos celulares incluindo apoptosis e ciclo celular. Na realidade, diversos estudos demonstram que a PP1 regula variadas proteínas que são elementos-chave no processo de tumorigenesis. A AKT, uma cinase serina/treonina que se encontra desregulada em vários tipos de cancro, é um factor crucial na progressão e sobrevivência de melanoma. Prodigiosina, um membro da família de metabolitos secundários tripirrolicos pigmentados de vermelho, as prodigininas, demonstra propriedades anticancerigenas em vários tipos de cancro. Na verdade alguns estudos verificaram que a AKT é desfosforilada pela prodigiosina embora ainda seja desconhecido o mecanismo pelo qual tal acontece. Dada a importância da AKT na progressão e sobrevivência do melanoma e a capacidade da PP1 em desfosforilar a AKT é possível que a PP1 esteja envolvida em tal mecanismo. Os resultados preliminares demonstraram que a PP1 liga-se a um membro da família das prodigininas provando a interacção entre estas moléculas. Por outro lado, ensaios em linhas celulares de melanoma usando tratamentos com prodigiosina e cantaridina, um inibidor da PP1, demonstraram que a prodigiosina afecta isoformas da PP1 diferencialmente. Estes resultados sugerem que a prodigiosina actua em duas vias de sinalização distintas em melanoma, a via da AKT e a da MAPK, uma vez que alteração nos níveis de PP1α, uma das isoformas da PP1, se correlaciona com a variação dos níveis de fosforilação da AKT e as mudanças nos níveis da PP1γ com a variação dos níveis de fosforilação da MAPK. Com estes resultados propomos um modelo de como a prodigiosina desfosforila a AKT e como este processo contribui para a indução da morte celular em células de melanoma. Esperamos que este modelo ajude na compreensão do mecanismo de acção da prodigiosina bem como no reconhecimento das fosfatases como novos alvos terapêuticos no tratamento de cancro.
Protein phosphorylation is a major regulatory mechanism for cell function. It is noteworthy that several pathologies, including cancer to be associated with abnormal phosphorylation of key proteins. Although many studies have addressed the kinases that are misregulated in cancer, much less is known about the phosphatases that counteract their actions. PP1, a major serine/threonine protein phosphatase that is ubiquitously expressed in all eukaryotic cells, is involved in many cellular processes including apoptosis and cell cycle. In fact, several studies demonstrate that PP1 regulates several proteins that are key elements in the tumorogenesis process. AKT, a serine/threonine kinase that is disregulated in several types of cancer is a crucial factor in melanoma progression and survival. Prodigiosin, a family member of the natural red pigmented tripyrrolic secondary metabolites, prodiginines, show anticancer properties in numerous types of cancer. In fact, some prodigiosin studies demonstrate that AKT is dephosphorylated by prodigiosin by an unknown mechanism. Given the importance of AKT in melanoma progression and survival and the capacity of PP1 to dephosphorylate AKT it is possible that PP1 is involved in this mechanism. Our preliminary results showed that PP1 binds to one member of prodiginine family proving the interaction between these molecules. On the other hand, experiments with melanoma cell lines, using prodigiosin and cantharidin, a PP1 inhibitor, treatments, demonstrate that prodigiosin affect differently PP1 isoforms. These results suggest that prodigiosin acts in a different way in two altered pathways in melanoma, AKT and MAPK, since the alterations in PP1α levels, one of PP1 isoforms, are correlated with the conversion in AKT dephosphorylation and the variations in PP1γ levels with the changes in MAPK dephosphorylation. Given these results we propose a model of how prodigiosin dephosphorylates AKT and how this process contributes to induce cell death in melanoma cells. We expect that this model helps to understand prodigiosin action mechanism as well as acknowledge phosphatases as a therapy target in cancer treatment.
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Ngamratanapaiboon, Surachai. "Metabolomics investigations of the effect of drugs on mammalian cells". Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/41178/.
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Cell-based metabolomics using LC-MS systemizes the study of the uniqueness of small-molecule metabolite (metabolomes) profiles in cellular processes. Cell-based metabolomics can potentially be used in many applications for the study of biological perturbation from stimulants in cellular pathways. The advantages of cell-based metabolomics include ease of control and interpretation when compared to the study of human subjects and animal models. Furthermore, this method can decrease some highly challenging problems that occur in genomics, transcriptomics and proteomics. Nowadays, cell culture in metabolomics studies has been used in many applications. These include cell culture and bioreactor optimisation, phenotype classification, stimulant testing effect, target and toxicity analysis, metabolic networks determination and modelling, and biomarker and drug target discovery. In this study, the reverse phase-liquid chromatography-mass spectrometry and hydrophilic interaction chromatography-mass spectrometry for comprehensive metabolic profiling well suited to the untargeted analysis of non-polar and polar metabolites in mammalian cells were developed, optimized and validated. These methods can separate and detect most of hydrophobic and polar metabolites that are normally found in mammalian cell lines. After that the LC-MS methods were applied to assess the effects of drugs with known and unknown cellular metabolic effects on three mammalian cell lines, namely HMVECs for antipsychotics experiment, MCF-7 cells for cordycepin experiment and MIN6 cells for fluoxetine experiment by using untargeted metabolic profiling. The global effects of antipsychotics at high therapeutic dosage in HMVECs were investigated. The results support for the toxicity hypothesis with measurements that confirm previous findings and reveal the exact biological pathways of antipsychotic-altered BBB functions. It was found that antipsychotics may affect the bioenergetics pathway due to mitochondrial dysfunction resulted in ketoacidosis and inducing oxide stress by reactive oxygen species generation. In the MCF- cell experiment, the results of the untargeted metabolite profiling demonstrated the clear anti-breast cancer effects of cordycepin and pentostatin. By investigating the metabolite profiles, clear synergistic effects of cordycepin and pentostatin combined in comparison to cordycepin activity alone in MCF-7 cells was observed. Furthermore, the pathway analysis indicated that anti-breast cancer activity was mainly responsible for alterations in purine and pyrimidine metabolism and bioenergetics. Additionally, cordycepin may be involved in the inhibition of cell proliferation and differentiation, and the activation of cell apoptosis. The last experiment on MIN6 cells, the developed and optimized HILIC-MS approach in order to determine the biological pathways which are impaired by fluoxetine on glucose-stimulated insulin secretion on MIN6 cell lines was performed. It is found that fluoxetine may impair glycolysis, TCA and fatty acid metabolism on MIN6 cell lines. Moreover, it is also reveal that the alteration of biological pathways on MIN6 cells by known ETC inhibitors (rotenone (Complex I inhibitor) antimycin (Complex III inhibitor)) and azide (a complex IV inhibitor). From comparison with these ETC inhibitors, it is found that fluoxetine may have the same effect pattern with azide.