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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Use of cytochrome P450 2E1 (CYP2E1) knockout transgenic mouse model to study the role of CYP2E1 in carbon tetrachloride- and alcohol-mediated hepatotoxicity.

January 1998 (has links)
by Wong Wing-yee, Felice. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 144-166). / Abstract also in Chinese. / Acknowledgements --- p.i / List of Abbreviations --- p.ii / Abstract --- p.iv / Abstract (Chinese Version) --- p.vi / Table of Contents --- p.viii / List of Tables --- p.xii / List of Figures --- p.xiv / List of Appendices --- p.xvi / Chapter Chapter I --- Literature Review / Chapter 1. --- Introduction --- p.1 / Chapter 2. --- Background of Cytochrome P450 --- p.3 / Chapter 2.1 --- Discovery --- p.3 / Chapter 2.2 --- Tissue Distribution --- p.3 / Chapter 2.3 --- Structure and Functions --- p.7 / Chapter 2.4 --- Nomenclature of the P450 Superfamily --- p.10 / Chapter 3. --- Cytochrome P450 2E1 (CYP2E1) --- p.11 / Chapter 3.1 --- Discovery --- p.11 / Chapter 3.2 --- Tissue Distribution --- p.12 / Chapter 3.3 --- Substrates and Inducers --- p.13 / Chapter 3.4 --- Toxicological Role of CYP2E1 --- p.15 / Chapter 4. --- CYP2E1-knockout Mouse Model --- p.17 / Chapter Chapter II --- Carbon Tetrachloride (CC14) Study / Chapter 1. --- Introduction --- p.19 / Chapter 1.1 --- General Properties and Usage of CC14 --- p.19 / Chapter 1.2 --- Toxicological Aspects of CC14 --- p.19 / Chapter 1.3 --- Mechanism of CCl4-induced Hepatotoxicity --- p.20 / Chapter 1.4 --- Role of CYP2E1 in CCl4-induced Hepatotoxicity --- p.23 / Chapter 1.5 --- Objectives of the Study --- p.27 / Chapter 2. --- Materials and Methods --- p.29 / Chapter 2.1 --- Chemicals and Materials --- p.29 / Chapter 2.2 --- Animals --- p.29 / Chapter 2.3 --- Acute CC14 Treatment --- p.29 / Chapter 2.4 --- Preparation of Microsomal Fractions --- p.30 / Chapter 2.5 --- Determination of Microsomal Protein Concentration --- p.31 / Chapter 2.6 --- Determination of Serum Aminotransferase Activities --- p.31 / Chapter 2.7 --- Liver Histology --- p.32 / Chapter 2.8 --- Hepatic Microsomal CYP2E1 Activity -p-nitrophenol Assay --- p.34 / Chapter 2.9 --- SDS-PAGE and Western Blot Analysis --- p.35 / Chapter 2.10 --- Detection of Lipid Peroxidation in vitro and in vivo --- p.35 / Chapter 2.10.1 --- In vitro Lipid Peroxidation - 2-Thiobarbituric Acid (TBA) assay --- p.35 / Chapter 2.10.2 --- In vivo Lipid Peroxidation - Microsomal Conjugated Dienes Detection --- p.36 / Chapter 2.11 --- Hepatic Lipid Fatty Acid Composition Analysis --- p.39 / Chapter 2.11.1 --- Lipid Extraction --- p.39 / Chapter 2.11.2 --- Thin Layer Chromatography --- p.39 / Chapter 2.11.3 --- Methylation --- p.40 / Chapter 2.11.4 --- Gas Chromatography --- p.40 / Chapter 2.12 --- Statistical Analysis --- p.41 / Chapter 3. --- Results --- p.42 / Chapter 3.1 --- "Mortality, Liver Weight and Liver Color" --- p.42 / Chapter 3.2 --- Hepatotoxicity --- p.42 / Chapter 3.2.1 --- Serum ALT and AST activities --- p.42 / Chapter 3.2.2 --- Liver Histology --- p.45 / Chapter 3.3 --- CYP2E1-catalysed PNP Activities and CYP2E1 Protein Levels --- p.49 / Chapter 3.3.1 --- CYP2El-catalyzed PNP Activities --- p.49 / Chapter 3.3.2 --- CYP2E1 Protein Levels --- p.52 / Chapter 3.4 --- Lipid Peroxidation --- p.52 / Chapter 3.4.1 --- In vitro Lipid Peroxidation --- p.52 / Chapter 3.4.2 --- In vivo Lipid Peroxidation --- p.54 / Chapter 3.5 --- Hepatic Lipid Fatty Acid Composition --- p.56 / Chapter 3.5.1 --- Fatty Acid Composition in Hepatic Phospholipid --- p.56 / Chapter 3.5.2 --- Fatty Acid Composition in Hepatic Microsomal Phospholipid --- p.59 / Chapter 3.5.3 --- Fatty Acid Composition in Hepatic Triglyceride --- p.61 / Chapter 4. --- Discussion --- p.63 / Chapter 4.1 --- CYP2E1 is Required in CCl4-mediated Hepatotoxicity --- p.63 / Chapter 4.2 --- CYP2E1 is Degraded following CC14 Exposure --- p.65 / Chapter 4.3 --- CYP2E1 is Required in CCl4-induced Lipid Peroxidation --- p.67 / Chapter 4.4 --- CYP2E1 is Required in CCl4-induced Hepatic Phospholipid Depletion --- p.70 / Chapter 4.5 --- CYP2E1 is Required in CCl4-induced Hepatic Triglyceride Accumulation --- p.72 / Chapter 5. --- Conclusion --- p.76 / Chapter Chapter III --- Chronic Ethanol Consumption Study / Chapter 1. --- Introduction --- p.77 / Chapter 1.1 --- Multiple Metabolic Pathways for Ethanol Metabolism --- p.77 / Chapter 1.2 --- Metabolism of Ethanol by the Microsomal Ethanol Oxidizing System --- p.79 / Chapter 1.3 --- Role of CYP2E1 in Ethanol Metabolism --- p.82 / Chapter 1.4 --- Role of CYP2E1 in Alcoholic Liver Disease and Associated Oxidative Stress --- p.84 / Chapter 1.5 --- Objectives of the Study --- p.89 / Chapter 2. --- Materials and Methods --- p.90 / Chapter 2.1 --- Chemicals and Materials --- p.90 / Chapter 2.2 --- Animals --- p.90 / Chapter 2.3 --- Chronic Ethanol Treatment --- p.90 / Chapter 2.3.1 --- Ethanol Diet Composition --- p.90 / Chapter 2.3.2 --- Ethanol Feeding --- p.90 / Chapter 2.4 --- Monitoring of Blood Ethanol Levels --- p.96 / Chapter 2.5 --- Preparation of Microsomal Fractions --- p.96 / Chapter 2.6 --- Determination of Microsomal Protein Concentration --- p.97 / Chapter 2.7 --- Determination of Serum Aminotransferase Activities --- p.98 / Chapter 2.8 --- Liver Histology --- p.98 / Chapter 2.9 --- SDS-PAGE and Western Blot Analysis --- p.99 / Chapter 2.10 --- Hepatic Fatty Acid Composition Analysis --- p.100 / Chapter 2.10.1 --- Lipid Extraction --- p.100 / Chapter 2.10.2 --- Thin Layer Chromatography --- p.101 / Chapter 2.10.3 --- Methylation --- p.101 / Chapter 2.10.4 --- Gas Chromatography --- p.102 / Chapter 2.11 --- Statistical Analysis --- p.103 / Chapter 3. --- Results --- p.104 / Chapter 3.1 --- Average Food Consumption --- p.104 / Chapter 3.2 --- Average Ethanol Consumption for Ethanol Liquid Diet Feeding Group --- p.104 / Chapter 3.3 --- Body Weight Gain --- p.104 / Chapter 3.4 --- Blood Ethanol Levels --- p.108 / Chapter 3.5 --- "Mortality, Liver Weight and Liver Color" --- p.108 / Chapter 3.6 --- Serum ALT and AST Activities --- p.110 / Chapter 3.7 --- Liver Histology --- p.114 / Chapter 3.8 --- Western Blot Analysis --- p.119 / Chapter 3.9 --- Hepatic Lipid Fatty Acid Composition --- p.119 / Chapter 3.9.1 --- Fatty Acid Composition in Hepatic Phospholipid --- p.119 / Chapter 3.9.2 --- Fatty Acid Composition in Hepatic Triglyceride --- p.123 / Chapter 4. --- Discussion --- p.126 / Chapter 4.1 --- Nutrients Displacement after Chronic Ethanol Consumption --- p.126 / Chapter 4.2 --- Varied Blood Ethanol Levels after Chronic Ethanol Consumption --- p.127 / Chapter 4.3 --- Increase in CYP2E1 Levels after Chronic Feeding of Ethanolin WT mice --- p.127 / Chapter 4.4 --- Lack of Evidence Indicating the Development of Ethanol- Induced Liver Injury --- p.129 / Chapter 4.4.1 --- No Elevations in Serum ALT and AST Activities --- p.129 / Chapter 4.4.2 --- Normal Liver Histology --- p.130 / Chapter 4.4.3 --- Lack of Triglyceride Accumulation --- p.131 / Chapter 4.4.4 --- Elevations in Hepatic PL --- p.132 / Chapter 4.5 --- Possible Reasons for the Absence of Liver Damage after Chronic Ethanol Consumption in our Mouse Model --- p.134 / Chapter 5. --- Conclusion --- p.137 / Chapter Chapter IV --- Concluding Remarks / Chapter 1. --- A Comparison between Acute CC14 Study and Chronic Ethanol Consumption Study --- p.139 / Chapter 1.1 --- Regulation of CYP2E1 Expression --- p.139 / Chapter 1.2 --- Free Radical Production Involved in CC14- and Chronic Ethanol Consumption-Mediated Liver Injury --- p.140 / Chapter 1.3 --- An Overall Comparison between CC14 study and Chronic Ethanol Consumption Study --- p.140 / Chapter 2. --- Future Studies --- p.142 / Chapter 2.1 --- Acute CC14 Study --- p.142 / Chapter 2.1.1 --- Calcium Homeostasis Studies --- p.142 / Chapter 2.1.2 --- Spin Trapping Studies --- p.142 / Chapter 2.2 --- Chronic Ethanol Study --- p.142 / Chapter 2.2.1 --- "Generation of a Heterozygous ""Ethanol-Sensitive"" Mouse Strain (SV/129/ter x C57BL/6)" --- p.143 / Chapter 3. --- Concluding Remarks --- p.143 / References --- p.144 / Appendix --- p.167
12

Variantes genéticas da N-acetiltransferase 2, CYP2E1 e glutationa S-transferase: relação com a segurança terapêutica em pacientes com tuberculose / Genetic variants of N-acetyltransferase 2, CYP2E1 and Glutathione S-transferase: relation with therapeutic safety in patients with tuberculosis

Forestiero, Francisco José 30 April 2009 (has links)
Polimorfismos nos genes da n-acetiltransferase 2 (NAT2), CYP2E1 e glutationa S-transferase (GST) têm sido associados a diferenças na resposta ao tratamento da tuberculose. O papel de variantes dos genes NAT2, CYP2E1 e GSTM1/GSTT1, no perfil de segurança do tratamento da tuberculose, foi avaliado em 99 pacientes com tuberculose, sem co-infecção por HIV ou vírus da hepatite, tratados por 6 meses. Amostras de sangue foram colhidas antes e durante o tratamento para avaliação de marcadores de lesão hepatocelular (ASLT e AST), colestase (ALP, GGT e bilirrubinas) e função renal (creatinina). O DNA genômico foi extraído de sangue colhido em EDTA pelo método precipitação salina. Os polimorfismos NAT2 foram analisados por PCR-RFLP e seqüenciamento de DNA. Os polimorfismos da região promotora do CYP2E1 foram detectados por PCR-RFLP e para a análise dos genótipos nulos de GSTM1 (GSTM1*0) e GSTT1 (GSTT1*0) foi utilizada a PCR multiplex. Durante o tratamento, 59,6% dos pacientes apresentaram reações adversas aos medicamentos (RAM) e alterações nos marcadores de lesão hepatocelular e colestase, com aumento de 1 a 4 vezes o limite superior de referência. Foi observada forte relação entre RAM e alterações nos marcadores séricos (p< 0,05) e também com o uso de medicação concomitante (p< 0,001). As freqüências dos alelos NAT2*4 e NAT2*6 foram maiores e menores, respectivamente, quando comparadas com outros estudos na população brasileira. O perfil de acetilador lento (alelos NAT2*5, NAT2*6 e NAT2*7) foi associado com manifestação de RAM e hepatotoxicidade. Os portadores dos genótipos NAT2*4/*5 e NAT2*5/*5 apresentaram, respectivamente, risco 2,4 e 5,0 vezes maior de RAM que os portadores dos demais genótipos NAT2 (p< 0,05). O genótipo funcional GSTM1*1/GSTT1*1 foi associado com alterações acentuadas de ALT, AST e ALP (p< 0,05). Enquanto que as variantes da CYP2E1 não foram associadas a alterações no perfil bioquímico ou com risco de RAM ou hepatotoxicidade. Em conclusão, o perfil de acetilação lenta de NAT2 e o genótipo funcional de GSTM1/GSTT1 aumentam a susceptibilidade de lesão hepatocelular e outras RAM induzidas pelos antimicobacterianos utilizados no tratamento da tuberculose. / Polymorphisms in N-acetiltransferase 2 (NAT2), CYP2E1 and glutatione S-transferase (GST) have been associated with differences in response to antituberculosis drugs. The role of the NAT2, CYP2E1 and GSTM1/GSTT1 variants on safety profile of the anti-tuberculosis therapy was evaluated in 99 tuberculosis patients, without co-infection by HIV or hepatitis virus, treated during 6 months. Blood samples were collected before and after the therapy to evaluate serum markers for hepatocelullar damage (ASLT and AST), cholestasis (ALP, GGT and bilirrubin) and kidney function (creatinine). Genomic DNA was extracted from EDTA-blood samples by salting-out method. NAT2 polymorphisms were analyzed by PCR-RFLP and DNA sequencing. CYP2E1 promoter region polymorphisms were detected by PCR-RFLP and for analysis of the null genotypes GSTM1 (GSTM1*0) e GSTT1 (GSTT1*0) PCR multiplex technique was used. During the therapy, 59.6% of the patients had adverse drug reactions (ADR) and alterations on hepatocellular damage and cholestasis serum markers, with increase of 1 to 4 times the upper limit reference level. There was a significant relationship between ADR and serum markers alterations (p< 0,05), as well as, the concomitant medicine (p< 0,001). The frequencies of the NAT2*4 and NAT2*6 alleles were higher and lower, respectively, when compared to other studies in the Brazilian population. The slow acetilator profile (NAT2*5, NAT2*6 and NAT2*7 alleles) was associated with ADR and hepatotoxicity manifestations. The NAT2*4/*5 and NAT2*5/*5 genotypes carriers had, respectively, 2.4 and 5.0 times higher risk for ADR than those carrying the other NAT2 genotypes (p< 0,05). The functional genotype GSTM1*1/GSTT1*1 was associated with enhanced variations on ALT, AST and ALP (p< 0.05). No relationship was found between CYP2E1 variants and variations on biochemical profile or risk for ADR or hepatotoxicity. In conclusion, the NAT2 slow acetilator profile and the GSTM1/GSTT1 functional genotype increase the susceptibility to hepatocellular damage and other ADR induced by antibiotics used in tuberculosis therapy.
13

Differential expression profile of cytochrome p450 2E1 (CYP2E1) related genes associated with carbon tetrachloride-induced hepatotoxicity. / CUHK electronic theses & dissertations collection

January 2004 (has links)
Avasarala Sreedevi. / "December 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 253-272) / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.
14

Effects of Danshen and its active components on rat CYP2E1 expression and metabolism of model CYP2E1 probe substrate.

January 2009 (has links)
Cheung, Ching Mei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 151-162). / Abstracts in English and Chinese. / ABSTRACT --- p.I / 論文摘要 --- p.IV / ACKNOWLEDGEMENT --- p.VI / TABLE OF CONTENTS --- p.VII / ABBREVIATIONS --- p.X / Chapter Chapter 1 --- p.1 / GENERAL INTRODUCTION --- p.1 / Chapter 1.1 --- DANSHEN --- p.1 / Chapter 1.1.1 --- LIPID-SOLUBLE COMPOUNDS EXTRACTED FROM DANSHEN --- p.2 / Chapter 1.1.1.1 --- TANSHINONE I --- p.2 / Chapter 1.1.1.2 --- TANSHINONE IIA --- p.3 / Chapter 1.1.1.3 --- CRYPTOTANSHINONE --- p.3 / Chapter 1.1.1.4 --- DIHYDROTANSHINONE --- p.4 / Chapter 1.1.2 --- WATER-SOLUBLE COMPOUNDS EXTRACTED FROM DANSHEN --- p.4 / Chapter 1.1.2.1 --- DANSHENSU --- p.4 / Chapter 1.1.2.2 --- SALVIANOLIC ACID B --- p.5 / Chapter 1.2 --- DRUG-DRUG INTERACTIONS --- p.5 / Chapter 1.2.1 --- PROBLEMS ASSOCIATED WITH HERBAL ADMINISTRATION --- p.5 / Chapter 1.2.2 --- HERB-DRUG INTERACTIONS --- p.7 / Chapter 1.2.2.1 --- ST. JOHŃةS WORT-DRUG INTERACTIONS --- p.8 / Chapter 1.2.2.2 --- WARFARIN-HERB INTERACTIONS --- p.9 / Chapter 1.2.2.3 --- DANSHEN-WARFARIN INTERACTIONS --- p.10 / Chapter 1.2.2.4 --- DANSHEN-DRUG INTERACTIONS --- p.11 / Chapter 1.3 --- CYTOCHROME P450 ENZYMES (CYP) --- p.12 / Chapter 1.3.1 --- CYTOCHROME P4502E1 --- p.13 / Chapter 1.4 --- AIMS OF STUDY --- p.17 / Chapter Chapter 2 --- p.21 / EFFECTS OF DANSHEN AND SOME IF ITS ACTIVE COMPONENTS ON CHLORZOXAZONE METABOLISM IN RAT AND HUMAN LIVER MICROSOMES IN VITRO --- p.21 / Chapter 2.1 --- INTRODUCTION --- p.21 / Chapter 2.2 --- MATERIALS AND METHODS --- p.23 / Chapter 2.2.1 --- CHEMICALS AND REAGENTS --- p.23 / Chapter 2.2.2 --- PREPARATION OF AQUEOUS FRACTION OF DANSHEN --- p.23 / Chapter 2.2.3 --- PREPARATION OF ETHANOLIC FRACTION OF DANSHEN --- p.23 / Chapter 2.2.4 --- ANIMALS --- p.24 / Chapter 2.2.5 --- PREPARATION OF RAT LIVER MICROSOMES --- p.25 / Chapter 2.2.6 --- POOLED HUMAN LIVER MICROSOMES --- p.25 / Chapter 2.2.7 --- PROTEIN ASSAY --- p.25 / Chapter 2.2.8 --- MICROSOMAL INCUBATION --- p.26 / Chapter 2.2.8.1 --- RAT LIVER MICROSOMES --- p.26 / Chapter 2.2.8.2 --- HUMAN LIVER MICROSOMES --- p.26 / Chapter 2.2.9 --- INHIBITION KINETICS STUDIES --- p.27 / Chapter 2.2.9.1 --- RAT LIVER MICROSOMES --- p.27 / Chapter 2.2.9.2 --- HUMAN LIVER MICROSOMES --- p.27 / Chapter 2.2.10 --- HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC) ANALYSIS --- p.28 / Chapter 2.2.11 --- DATA ANALYSIS --- p.28 / Chapter 2.3 --- RESULTS --- p.31 / Chapter 2.3.1 --- EFFECT OF DANSHEN AND TANSHINONES ON RAT CYP2E1 ACTIVITY IN VITRO / Chapter 2.3.1.1 --- SUMMARY --- p.57 / Chapter 2.3.2 --- EFFECT OF DANSHEN AND TANSHINONES ON HUMAN CYP2E1 ACTIVITYIN VITRO --- p.58 / Chapter 2.3.2.1 --- SUMMARY --- p.84 / Chapter 2.4 --- DISCUSSION --- p.85 / Chapter Chapter 3 --- p.93 / EFFECTS OF DANSHEN ON CYTOCHROME P450 PROTEIN EXPRESSION AND METABOLISM OF MODEL CYP2E1 PROBE SUBSTRATE IN THE RAT IN VIVO --- p.93 / Chapter 3.1 --- INTRODUCTION --- p.93 / Chapter 3.2 --- MATERIALS AND METHODS --- p.97 / Chapter 3.2.1 --- CHEMICALS AND REAGENTS --- p.97 / Chapter 3.2.2 --- ANIMALS --- p.97 / Chapter 3.2.3 --- EFFECTS OF DANSHEN TREATMENTS ON PHARMACOKINETICS OF CHLORZOXAZONE IN RATS IN VIVO --- p.98 / Chapter 3.2.3.1 --- "ACUTE, 3-DAY AND 14-DAY TREATMENTS WITH WHOLE DANSHEN EXTRACT" --- p.98 / Chapter 3.2.3.2 --- PLASMA EXTRACTION --- p.99 / Chapter 3.2.3.3 --- HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC) ANALYSIS --- p.99 / Chapter 3.2.4 --- EFFECTS OF 3-DAY AND 14-DAY DANSHEN TREATMENTS ON CYP2E1 PROTEIN EXPRESSION --- p.101 / Chapter 3.2.4.1 --- PREPARATION OF RAT LIVER MICROSOMES FOR WESTERN BLOTTING --- p.101 / Chapter 3.2.4.2 --- PROTEIN ASSAY --- p.101 / Chapter 3.2.4.3 --- WESTERN BLOT --- p.102 / Chapter 3.2.5 --- DATA ANALYSIS --- p.103 / Chapter 3.3 --- RESULTS --- p.105 / Chapter 3.3.1 --- EFFECTS OF WHOLE DANSHEN EXTRACT ON RAT CYP2E1 ACTIVITIES IN VIVO --- p.105 / Chapter 3.3.1.1 --- EFFECTS OF ACUTE TREATMENTS OF WHOLE DANSHEN EXTRACT ON PHARMACOKINETICS OF CHLORZOXAZONE --- p.105 / Chapter 3.3.1.2 --- EFFECTS OF 3-DAY TREATMENTS OF WHOLE DANSHEN EXTRACT ON PHARMACOKINETICS OF CHLORZOXAZONE --- p.106 / Chapter 3.3.1.3 --- EFFECTS OF 14-DAY TREATMENTS OF WHOLE DANSHEN EXTRACT ON PHARMACOKINETICS OF CHLORZOXAZONE --- p.107 / Chapter 3.3.2 --- EFFECTS OF WHOLE DANSHEN EXTRACT ON RAT CYP2E1 EXPRESSION .… --- p.137 / Chapter 3.3.3 --- SUMMARY --- p.140 / Chapter 3.4 --- DISCUSSION --- p.141 / CHAPTER 4 --- p.145 / GENERAL DISCUSSION --- p.145 / REFERENCES --- p.151
15

Variantes genéticas da N-acetiltransferase 2, CYP2E1 e glutationa S-transferase: relação com a segurança terapêutica em pacientes com tuberculose / Genetic variants of N-acetyltransferase 2, CYP2E1 and Glutathione S-transferase: relation with therapeutic safety in patients with tuberculosis

Francisco José Forestiero 30 April 2009 (has links)
Polimorfismos nos genes da n-acetiltransferase 2 (NAT2), CYP2E1 e glutationa S-transferase (GST) têm sido associados a diferenças na resposta ao tratamento da tuberculose. O papel de variantes dos genes NAT2, CYP2E1 e GSTM1/GSTT1, no perfil de segurança do tratamento da tuberculose, foi avaliado em 99 pacientes com tuberculose, sem co-infecção por HIV ou vírus da hepatite, tratados por 6 meses. Amostras de sangue foram colhidas antes e durante o tratamento para avaliação de marcadores de lesão hepatocelular (ASLT e AST), colestase (ALP, GGT e bilirrubinas) e função renal (creatinina). O DNA genômico foi extraído de sangue colhido em EDTA pelo método precipitação salina. Os polimorfismos NAT2 foram analisados por PCR-RFLP e seqüenciamento de DNA. Os polimorfismos da região promotora do CYP2E1 foram detectados por PCR-RFLP e para a análise dos genótipos nulos de GSTM1 (GSTM1*0) e GSTT1 (GSTT1*0) foi utilizada a PCR multiplex. Durante o tratamento, 59,6% dos pacientes apresentaram reações adversas aos medicamentos (RAM) e alterações nos marcadores de lesão hepatocelular e colestase, com aumento de 1 a 4 vezes o limite superior de referência. Foi observada forte relação entre RAM e alterações nos marcadores séricos (p< 0,05) e também com o uso de medicação concomitante (p< 0,001). As freqüências dos alelos NAT2*4 e NAT2*6 foram maiores e menores, respectivamente, quando comparadas com outros estudos na população brasileira. O perfil de acetilador lento (alelos NAT2*5, NAT2*6 e NAT2*7) foi associado com manifestação de RAM e hepatotoxicidade. Os portadores dos genótipos NAT2*4/*5 e NAT2*5/*5 apresentaram, respectivamente, risco 2,4 e 5,0 vezes maior de RAM que os portadores dos demais genótipos NAT2 (p< 0,05). O genótipo funcional GSTM1*1/GSTT1*1 foi associado com alterações acentuadas de ALT, AST e ALP (p< 0,05). Enquanto que as variantes da CYP2E1 não foram associadas a alterações no perfil bioquímico ou com risco de RAM ou hepatotoxicidade. Em conclusão, o perfil de acetilação lenta de NAT2 e o genótipo funcional de GSTM1/GSTT1 aumentam a susceptibilidade de lesão hepatocelular e outras RAM induzidas pelos antimicobacterianos utilizados no tratamento da tuberculose. / Polymorphisms in N-acetiltransferase 2 (NAT2), CYP2E1 and glutatione S-transferase (GST) have been associated with differences in response to antituberculosis drugs. The role of the NAT2, CYP2E1 and GSTM1/GSTT1 variants on safety profile of the anti-tuberculosis therapy was evaluated in 99 tuberculosis patients, without co-infection by HIV or hepatitis virus, treated during 6 months. Blood samples were collected before and after the therapy to evaluate serum markers for hepatocelullar damage (ASLT and AST), cholestasis (ALP, GGT and bilirrubin) and kidney function (creatinine). Genomic DNA was extracted from EDTA-blood samples by salting-out method. NAT2 polymorphisms were analyzed by PCR-RFLP and DNA sequencing. CYP2E1 promoter region polymorphisms were detected by PCR-RFLP and for analysis of the null genotypes GSTM1 (GSTM1*0) e GSTT1 (GSTT1*0) PCR multiplex technique was used. During the therapy, 59.6% of the patients had adverse drug reactions (ADR) and alterations on hepatocellular damage and cholestasis serum markers, with increase of 1 to 4 times the upper limit reference level. There was a significant relationship between ADR and serum markers alterations (p< 0,05), as well as, the concomitant medicine (p< 0,001). The frequencies of the NAT2*4 and NAT2*6 alleles were higher and lower, respectively, when compared to other studies in the Brazilian population. The slow acetilator profile (NAT2*5, NAT2*6 and NAT2*7 alleles) was associated with ADR and hepatotoxicity manifestations. The NAT2*4/*5 and NAT2*5/*5 genotypes carriers had, respectively, 2.4 and 5.0 times higher risk for ADR than those carrying the other NAT2 genotypes (p< 0,05). The functional genotype GSTM1*1/GSTT1*1 was associated with enhanced variations on ALT, AST and ALP (p< 0.05). No relationship was found between CYP2E1 variants and variations on biochemical profile or risk for ADR or hepatotoxicity. In conclusion, the NAT2 slow acetilator profile and the GSTM1/GSTT1 functional genotype increase the susceptibility to hepatocellular damage and other ADR induced by antibiotics used in tuberculosis therapy.
16

Uticaj tretmana akrilamidom na endokrini pankreas pacova / Effect of acrylamide treatment on endocrine pancreas of the rats

Stošić Milena 22 June 2018 (has links)
<p>Akrilamid&nbsp; je toksična hemijska supst anca koja je već dugi niz godina prisutna u životnoj sredini,&nbsp; jer se kao važan monomer koristi u različite industrijske i laboratorijske svrhe. U poslednjih petnaest godina, akrilamid je postao posebno zanimljiv za &scaron;ire naučne krugove jer&nbsp; se pokazalo da&nbsp; se&nbsp; nalazi&nbsp; i u&nbsp; hrani&nbsp; biljnog porekla, posebno hrani bogatoj skrobom, koja se priprema pečenjem ili prženjem na temperaturama vi&scaron;im od 120&deg;C.&nbsp; Do sada ustanovljeni negativni zdravstveni efekti akrilamida su veoma raznovrsni i mogu biti rezultat delovanja samog&nbsp; akrilamida ili delovanja njegovog metabolita glicidamida koji nastaje&nbsp; in vivo&nbsp; kada se jedan deo molekula akrilamida metaboli&scaron;e oksigenacijom dvostruke veze pomoću enzima citohrom P450 2E1 (CYP2E1). Akrilamid je supstanca koja ima dokazan negativan efekat&nbsp; na organske sisteme kod ljudi i životinja, i koja je svrstana u moguće humane karcinogene. Negativan efekat akrilamida na egzokrini pankreas je poznat, ali o mogućim efektima akrilamida na endokrini pankreas se i dalje veoma malo zna. Ima puno dokaza koji&nbsp; ukazuju na to da akrilamid ima citotoksični efekat koji se&nbsp; manifestuje kroz uticaj na redoks-status ćelija i dovodi do promena u vrednostima biomarkera oksidativnog i nitrozativnog stresa, kao i u aktivnosti antioksidativnih enzima. Pankreas&nbsp; je&nbsp; jedan od ciljnih&nbsp; organa za delovanje akrilamida te je&nbsp; glavni predmet istraživanja&nbsp; doktorske teze&nbsp; bio proučavanje potencijalnog efekta akrilamida na endokrini pankreas pacova.&nbsp; Ispitivanje je vr&scaron;eno na 3&nbsp; eksperimentalne grupe&nbsp; juvenilnih&nbsp; mužjaka pacova soja Wistar,&nbsp; od kojih je&nbsp; jedna grupa bila kontrolna, dok su dve bile tretirane&nbsp; sa akrilamidom u dozama od 25 mg/kg tm i 50 mg/kg tm,&nbsp; 5 dana nedeljno,&nbsp; tokom 3 nedelje. Po isteku tretmana,&nbsp; nakon dekapitacije, kompletno tkivo pankreasa&nbsp; je&nbsp; fiksirano u 10% rastvoru formalina&nbsp; tokom&nbsp; 24&nbsp; h i obrađeno prema&nbsp; standardnoj proceduri za kalupljenje u parafinu.&nbsp; Parafinski kalupi su sečeni na serijske preseke debljine 5 &micro;m, nakon čega su bojeni&nbsp; histohemijskom i imunohistohemijskim metodama.&nbsp; Kod eksperimentalnih grupa posmatrane&nbsp; su&nbsp; histolo&scaron;ke promene na endokrinom pankreasu, sa akcentom na &alpha;-&nbsp; i &beta;-ćelije.&nbsp; Takođe, posmatrana je&nbsp; i&nbsp; ekspresija&nbsp; hormona insulina i glukagona, enzima inducibilne azot -oksi d&nbsp; sintetaze (iNOS) i&nbsp; CYP2E1,&nbsp; kao&nbsp; i ekspresija&nbsp;&nbsp; antioksidativnih enzima&nbsp; katalaza&nbsp; (CAT) i superoksid dismut aza 1 i 2&nbsp; (SOD1 i SOD2)&nbsp; u ćelijama Langerhansovih ostrvaca. Potencijalna promena u funkcionalnosti &beta;-ćelija je ispitana i kroz analizu nivoa glukoze u serumu pacova tretiranih sa akrilamidom.<br />Budući da &beta;-ćelije čine 80% ćelija koje grade Langerhansova ostrvca pankreasa,&nbsp; pored in vivo&nbsp; eksperimenata, ispitana&nbsp; je&nbsp; i toksičnost akrilamida na&nbsp; Rin-5F ćelijsku liniju insulinoma &beta;-ćelija pacova u in vitro uslovima. Glavni cilj in vitro&nbsp; istraživanja je bio&nbsp; da se&nbsp; ispita&nbsp; uticaj&nbsp; rastućih&nbsp; koncentracija akrilamida na preživljavanje tretiranih&nbsp; Rin-5F&nbsp; ćelija, ali i efekat IC<sub>50</sub>&nbsp; koncentracije ove supstance primenjene&nbsp; tokom&nbsp; različitih vremenskih intervala&nbsp; (0,5, 1, 3, 6, 12 i 24 h)&nbsp; na pojavu oksidativnog i nitrozativnog stresa. Redoks-status Rin-5F ćelija tretiranih&nbsp; sa akrilamidom je ispitan preko analize prisustva biomarkera oksidativnog i nitrozativnog stresa, akrivnosti CAT i ukupne SOD, kao i promene u ekspresiji gena za CAT, SOD1, SOD2&nbsp;&nbsp; i iNOS.&nbsp; Pored toga, analiziran je i efekat istog tretmana na&nbsp; ekspresiju gena za insulin, CYP2E1, Bax i Bcl-2. U okviru teze je pokazano da akrilamid ne dovodi do&nbsp; značajnih promena u histolo&scaron;koj građi, dijametru i broju Langerhansovih ostrvaca&nbsp; kod&nbsp; tretiranih životinja.&nbsp; Primena stereolo&scaron;kih metoda&nbsp; je&nbsp; ukazala&nbsp; na mikrostrukturne promene na&nbsp; endokrinom pankreasu na nivou &alpha;-&nbsp; i &beta;-ćelija. U ovoj tezi je po prvi put pokazano da tretman akrilamidom negativno utiče na broj i povr&scaron;inu &beta;-ćelija pankreasa.&nbsp; U tezi je, takođe,&nbsp; pokazan&nbsp; značajan dozno-zavisni pad u prisustvu insulina u &beta;-ćelijama&nbsp;&nbsp; pankreasa. Uprkos&nbsp; tome, kod&nbsp; akrilamidom tretiranih&nbsp; životinja&nbsp; nije konstatovana&nbsp; promena&nbsp; u&nbsp; koncentraciji serumske glukoze.&nbsp; U&nbsp; ovoj tezi je pokazano da tretman akrilamidom dovodi do&nbsp;&nbsp; statistički značajnog porasta&nbsp; u broju &alpha;-ćelija&nbsp; kod životinja koje su primale nižu dozu tretmana, dok se&nbsp; broj &alpha;-ćelija&nbsp; kod životinja koje su primale vi&scaron;u dozu tretmana&nbsp; ne razlikuje značajno od kontrole.&nbsp; Tretman akrilamidom je doveo do značajnog&nbsp; porasta u količini&nbsp;&nbsp; prisutnog glukagona&nbsp; u &alpha;-ćelijama pankreasa.<br />Tretman akrilamidom nije doveo do značajne promene u ekspresiji CAT, SOD1 i SOD2 u ćelijama Langerhansovih ostrvaca.&nbsp; Kod&nbsp; tretiranih životinja&nbsp; do&scaron;lo do značajnog dozno-zavisnog porasta&nbsp; u ekspresiji&nbsp; enzima iNOS,&nbsp; dok je ekspresija&nbsp; CYP2E1 značajno dozno-zavisno opala&nbsp; nakon tretmana. U&nbsp; tezi je pokazano da tretman akrilamidom negativno utiče na vijabilnost Rin-5F ćelija, i utvrđeno je da IC50&nbsp; koncentracija akrilamida za Rin-5F ćelije iznosi 10 mM.&nbsp; Rezultati teze pokazuju da tretman akrilamidom u IC<sub>50</sub>&nbsp; koncentraciji u Rin-5F ćelijskoj liniji značajno povećava nivo malondialdehida (MDA) nakon tretmana u trajanju od 1, 12 i 24 h.&nbsp; Isti tretman&nbsp; značajno smanjuje nivo redukovanog GSH nakon tretmana od 1, 3, 6, 12 i<br />24 h, kao i nivo slobodnih&nbsp; &ndash;SH grupa nakon tretmana od 3 i 6 h. Tretman akrilamidom u IC<sub>50&nbsp;</sub> koncentraciji signifikantno pojačava aktivnost CAT nakon tretmana od 1 h, dok tretman u trajanju od 12 h značajno smanjuje aktivnost ovog enzima. Ovaj tretman smanjuje aktivnost SOD nakon 1, 12 i 24 h, dok&nbsp; tretman u trajanju od 6 h značajno pojačava aktivnost enzima SOD.&nbsp; U tezi je, takođe, pokazan i veoma značajan porast&nbsp; u nivou prisutnih nitrita,&nbsp; koji&nbsp; je direktno proporcionalan&nbsp; sa nivoom azot-oksida i nivoom akivnosti enzima iNOS.&nbsp; Ovaj&nbsp; nalaz ukazuje na potencijalnu pojavu nitrozati vnog stresa u akrilamidom-tretiranim Rin-5F ćelijama.&nbsp; U&nbsp; tezi je po prvi put pokazano da tretman&nbsp; akrilamidom dovodi do&nbsp; značajnih&nbsp; varijacija&nbsp; u transkripciji gena za iNOS, SOD1, SOD2,&nbsp; CAT,&nbsp; CYP2E1,&nbsp; Bax i Bcl-2 u tretiranim Rin-5F ćelijama, dok isti tretman ne dovodi do&nbsp; promene nivoa&nbsp; transkripcije gena za insulin.&nbsp; Tretman akrilamidom u koncentraciji od 10<br />mM tokom rastućih vremenskih perioda dovodi do porasta u relativnoj količini iRNK<br />gena za iNOS u svim tačkama tretmana, do porasta&nbsp; nivoa&nbsp; iRNK za SOD1 i SOD2 nakon tretmana od 12 i 24 h, kao i do porasta&nbsp; količine&nbsp; iRNK za CAT nakon tretmana od 3 h.&nbsp; U&nbsp; tezi je pokazano&nbsp; i&nbsp; da akrilamid&nbsp; izaziva&nbsp; promene&nbsp; u sintezi&nbsp; iRNK&nbsp; za enzim&nbsp; CYP2E1&nbsp; koji je&nbsp; posebno značajan u kontekstu detoksikacije ove toksične supstance.&nbsp; Porast u transkripciji gena za&nbsp; CYP2E1&nbsp; je uočen&nbsp; nakon tretmana u trajanju od 0,5 i 1 h, dok je&nbsp; do smanjenja transkripcije&nbsp; do&scaron;lo&nbsp; nakon tretmana od 12&nbsp; i 24&nbsp; h.&nbsp; Tretman akrilamidom u koncentraciji od&nbsp; 10 mM tokom rastućih vremenskih perioda dovodi do porasta u relativnoj količini iRNK&nbsp; gena za Bax u svim tačkama tretmana, i do porasta u transkripciji gena za Bcl-2 nakon tretmana od 0,5, 1 i 3 h.<br />Sumirajući&nbsp; sve&nbsp; rezultate&nbsp; ove teze,&nbsp; moze se zaključiti&nbsp; da je endokrini pankreas&nbsp; jedno od&nbsp; ciljnih tkiva, na koje akrilamid ostvaruje vi&scaron;estruki negativni uticaj.</p> / <p>Acrylamide is a toxic chemical used as an important monomer for various industrial and laboratory purposes, which makes it highly present in the environment. In the last fifteen years, acrylamide has become especially interesting for wider scientific circles when it was found in staple foodstuff rich in starch, prepared at temperatures higher than 120&deg;C. The established negative health effects of acrylamide are very diverse and can be the result of the acrylamide action itself or the action of its metabolite glycidamide that occurs in vivo, when acrylamide molecule is metabolized via oxygenation of the double bond by the cytochrome P450 2E1 (CYP2E1). Acrylamide is a substance with a proven adverse effect on humans and animals, and it is classified as a possible human carcinogen. The negative effect of acrylamide on the exocrine pancreas has already been recognized, but the possible effects of acrylamide&nbsp; on endocrine pancreas are still mostly undetermined. There is a significant amount of evidence to suggest that acrylamide exerts a cytotoxic effect which manifests through the changes in level of oxidative and nitrosative stress biomarkers, as well as in the activity of antioxidant enzymes. Since, pancreas is one of the target organs for acrylamide, the main subject of doctoral thesis was to investigate the potential effect of acrylamide on the rat endocrine pancreas. The investigation was conducted on 3 experimental groups of juvenile male Wistar rats, of which one group was the control group, while two groups were treated with acrylamide at doses of 25 mg/kg bw and 50 mg/kg bw, 5 days a week, during 3 weeks. After termination of the treatment, decapitation was performed, and the complete pancreatic tissue was fixed in a 10% formalin solution for 24 h and treated according to the standard paraffin embedding procedure. Paraffin molds were cut into 5 &mu;m thick serial sections, after which they were stained with histochemical and immunohistochemical methods. Histological changes ofthe endocrine pancreas, with the emphasis on &alpha;- and &beta;-cells, were examined in three experimental groups of rats. In addition, the expression of insulin and glucagon hormone, the inducible nitric oxide synthase (iNOS) and CYP2E1 enzymes, and the expression of antioxidative enzymes catalase (CAT) and superoxide dismutases 1 and 2&nbsp; (SOD1 and SOD2) in the islets of Langerhans were also investigated. A potential change in the functionality of &beta;-cells was also examined by analyzing glucose level in the serum of rats treated with acrylamide. In pancreatic islets of Langerhans the majority of cells (&gt;80%) are &beta;-cells. Therefore, in addition to in vivo experiments, the toxicity of acrylamide was examined in vitro on rat insulinoma Rin-5F cell line.The main goal of in vitro research was to investigate the impact of increasing acrylamide concentrations on the viability of treated Rin-5F cells, and also to examine whether IC50 concentration of this substance, applied at different intervals of time (0.5, 1, 3, 6, 12 and 24 h), induce oxidative and nitrosative stress. Redox-status of Rin-5F cells treated with acrylamide was examined by analyzing oxidative and nitrosative stress biomarkers, CAT and total SOD activity, as well as changes in the expression of the CAT, SOD1, SOD2 and iNOS. In addition, the effect of the same treatment on the transcription of the insulin, CYP2E1, Bax and Bcl-2 gene was analyzed.The results of the thesis showed that acrylamide treatment does not lead to significant changes in the histological structure, diameter and number of islets of Langerhans of treated animals. Application of stereological methods indicated microstructural changes of &alpha;- and &beta;-cells ofendocrine pancreas. It has been shown for the first time that treatment with acrylamide negatively affects the number and surface area of pancreatic &beta;-cells. In addition, a significant dose-dependent decline in the amount of insulin in pancreatic &beta;-cells was also demonstrated. However, no change in serum glucose level was observed in treated animals. Acrylamide treatment led to a statistically significant increase in the number of &alpha;-cells in animals receiving a lower dose of treatment, while the number of &alpha;-cells in animals receiving a higher dose of treatment did not differ significantly from the control. Treatment with acrylamide led to a significant increase in the amount of the glucagon in &alpha;-cells. Treatment with acrylamide did not cause a significant change in the expression of CAT, SOD1 and SOD2 in islets of Langerhans. However, there was a significant dosedependent increase in the&nbsp; expression of iNOS enzyme, whereas expression of CYP2E1 significantly decreased in dose-dependent manner in treated animals. Results of the thesis showed that acrylamide exerts a negative effect on the viability of Rin-5F cell line. It has been established that the IC50 concentration of acrylamide for the Rin-5F cell line is 10 mM. The results of the thesis indicate that treatment of Rin-5F cell line with IC50 concentration of acrylamide for 1, 12, and 24 h significantly increased the level of malondialdehyde (MDA). Exposure to acrylamide for 1, 3, 6, 12 and 24 h significantly decreased the level of reduced GSH, while the level of free -SH groups was reduced after 3 and 6 h of acrylamide treatments. Treatment with IC50 concentration of acrylamide significantly enhanced CAT activity after 1 h of acrylamide exposure, while 12 h exposure significantly reduced the activity of this enzyme. Application of acrylamide reduced SOD activity after 1, 12, and 24 h exposure, while 6 h exposure significantly increased the activity of SOD enzymes. Results of the thesis also showed a very significant increase of the nitrite level, which is directly proportional to the level of nitrogen oxide (NO) and the level of the iNOS activity. This finding points to the potential occurrence of nitrosative stress in acrylamide-treated Rin-5F cells. It has been shown for the first time that acrylamide treatment leads to significant variations in transcription of iNOS, SOD1, SOD2, CAT, CYP2E1, Bax and Bcl-2 genes in treated Rin-5F cells, while the same treatment does not affect transcription of the insulin gene. Treatment with acrylamide at a concentration of 10 mM for increasing periods of time leads to an increase in the relative amount of the iNOS gene iRNA at all treatment points. Twelve and and 24 h of acrylamide exposure increased the transcription of the SOD1 and SOD2 genes. Transcription of CAT gene was increased after 3 h&nbsp; ofacrylamide exposure. Furthermore, it has been shown that acrylamide treatment leads to variations in the mRNA synthesis of CYP2E1 gene, which is particularly significant in the context of detoxification of this toxic substance. An increase in the transcription ofthe CYP2E1&nbsp; gene was observed after 0.5 and 1 h of acrylamide exposure, while the reduction of&nbsp; transcription occurred after 12 and 24 h of acrylamide exposure. The treatment with 10 mM acrylamide has led to an increase of the transcription of the Bax gene at all treatment points, and also to an increase of transcription of the Bcl-2 gene after of 0.5, 1, and 3 h of acrylamide exposure. Summarizing all the results of this thesis, it can be concluded that the endocrine pancreas&nbsp; is one of the target tissues of acrylamide, to which this substance exerts a multiple adverse effects.</p>
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HEPATIC CYTOCHROME P450 REDUCTASE-NULL MICE AS AN ANIMAL MODEL TO STUDY ELECTRON TRANSFER PATHWAYS IN CHOLESTEROL SYNTHESIS AND CYP2E1-MEDIATED DRUG METABOLISM

Li, Li 01 January 2006 (has links)
NADPH-cytochrome P450 reductase (CPR) is a flavoprotein containing both FAD and FMN and functions as the electron donor protein for several oxygenase enzymes found on the endoplasmic reticulum of eukaryotic cells, including cytochrome P450s involved in drug metabolism and cholesterol biosynthesis. As many as three enzymes in the cholesterol biosynthetic pathway have been demonstrated, or proposed, to use CPR as a redox partner: squalene monooxygenase, which converts squalene to 2,3-oxidosqualene; lanosterol demethylase, a cytochrome P450 (CYP51); and 7-dehydrocholesterol reductase, the final step in cholesterol synthesis. In yeast CPR can be replaced by the NADH-cytochrome b5 pathway, but this has not been demonstrated in animals or plants. My studies with hepatic cytochrome P450 reductase-null mice have revealed a second microsomal reductase for squalene monooxygenase that was not previously detected. Studies carried out with hepatocytes from CPR-null mice demonstrate that this second reductase is active in whole cells and leads to the accumulation of 24-dihydrolanosterol, indicating that lanosterol demethylation, catalyzed by CYP51, is blocked. These results demonstrate that this second reductase plays a significant role in supporting squalene monooxygenase but not cytochrome P450-mediated reactions. 7-Dehydrocholesterol reductase (E.C. 1.3.1.21) catalyzes the reduction of the 7-8 double bond of 7-dehydrocholesterol to yield cholesterol. It has been suggested that cytochrome-P450 reductase is required for this reaction. My studies show that 7-dehydrocholesterol reductase is enzymatically active in CPR-null microsomes, with activity equal to or greater than that found in preparations from wild-type mice. Mammalian cytochrome b5, which can accept electrons from either cytochrome P450 reductase or NADH-cytochrome b5 reductase, is known to be involved in augmenting some P450-dependent monooxygenase reactions. Cytochrome P450 2E1 has been found to exhibit reasonable rates of turnover via an NADHcytochrome b5 pathway in reconstituted enzyme systems and in heterologous hosts. Using microsomes from hepatic CPR-null mice, I have determined that NADH-dependent CYP2E1 activity in the absence of NADPH-dependent activity constituted approximately 10% of CYP2E1 activity observed in microsomal preparations with NADPH from wild-type mice. However, little or no CYP2E1 activity could be detected in primary hepatocytes isolated from CPR-null mice.
18

Proteomics of Oxidative Stress Using Inducible CYP2E1 Expressing HepG2 Cells and 3T3-L1 Adipocytes as Model Systems

Newton, Billy Walker 2011 May 1900 (has links)
The overall goal of this research was to investigate oxidative stress related changes to the proteomes of 3T3-L1 adipocytes and an inducible CYP2E1 expressing HepG2 cells. Enhanced oxidative stress in hypertrophic adipocytes is associated with metabolic dysregulation and insulin resistance. Because mitochondria generate reactive oxygen species (ROS), we monitored changes to the adipocyte mitochondrial proteome during differentiation and enlargement. We labeled mitochondrial extracts from 3T3-L1 cells that were 0, 4, 7, 10, 14, and 18 days post differentiation with iTRAQ, followed by MS based identification. We found citric acid cycle proteins such as pyruvate carboxylase, citrate synthase, as well as beta-oxidation enzymes; cartinine acyl transferase and long-chain enoyl-CoA hydratase up-regulated from 7 through 18 days post differentiation onset. These data indicate TCA up-regulation for enhanced metabolic and citrate output necessary for lipid synthesis in adipocytes. Paradoxically, the data also show the simultaneous increase in the fatty acid oxidation, indicating a metabolic overdrive state. Biochemical assays showing peaks in ATP and ROS generation in 3 day old adipocytes provide further evidence of this overdrive state. A second peak in ROS generation occurred in 10 day old adipocytes; concurrent ATP generation reduced to near pre-adipocyte levels and this may indicate a metabolic shift that may be responsible for increased oxidative stress in hypertrophic adipocytes. We developed a doxycycline inducible CYP2E1 expressing HepG2 cell line using the pTet-On/pRevTRE expression system to allow greater control and sensitivity in the generation CYP2E1 mediated oxidative stress. Our cell line (RD12) demonstrated stability and tight expression control. After induction, RD12 cells showed 30 percent higher CYP2E1 activity when compared to the constitutive E47 cell line. RD12 cells showed 30 percent greater toxicity than E47 cells and 25 percent less free glutathione when exposed to 20 mM acetaminophen, indicating RD12 cells are more sensitive to the effects reactive intermediates and oxidative stress generated by CYP2E1. We conducted a survey of the toxicity of dietary fatty acids (oleic, linoleic, and palmitic) on HepG2 cells to determine fatty acid doses that induced metabolic changes, but did not cause excessive cell death. The dose of 0.20 mM linoleic and palmitic acid for 48 hours produced low toxicity, but oleic acid actually produced lower toxicity than untreated cells. After exposure cells were treated with a pro-oxidant to determine which fatty acid increased the susceptibility to protein carbonylation. The carbonylated protein isolation procedure indicated the palmitic acid may induce more carbonylation than oleic acid, but greater efficiency in the isolation procedure is required for a confidant determination.
19

In Vivo Interaction Of Carcinogenic Acrylamide With Cytochrome P450 Isozymes And Phase Ii Enzymes In Rabbit Liver, Kidney And Lung

Nuyan, Mine 01 December 2008 (has links) (PDF)
Acrylamide is an industrially produced chemical with known neurotoxic, reproductive toxin and carcinogenic effects. The carcinogenicity associated with acrylamide is mostly attributed to its metabolism by liver CYP2E1. However, studies investigating the effects of acrylamide on CYP2E1 enzyme are limited. In this study, it was aimed to investigate in vivo interaction of carcinogenic acrylamide on microsomal cytochrome P450 enzyme activities, and protein levels, and on cytosolic NQO1 and GST enzyme activities of rabbit liver, kidney and lung of acrylamide-treated rabbits. The in vivo protective effect of resveratrol, a phenolic compound, was also investigated on acrylamide toxicity. New Zealand male rabbits were treated with acrylamide and resveratrol, separately in different doses and conditions. Their combined effects were also investigated. CYP2E1-dependent p-Nitrophenol hydroxylase, NDMA N-demethylase and aniline 4-hydroxylase activities were found to be significantly increased in acrylamide-treated rabbit liver (1.80-3.0 fold) and kidney (1.6-fold). Rabbit liver and kidney CYP2E1 protein levels (determined by western blot analyisis) also increased approximately 2-fold due to acrylamide treatment. In rabbit liver, resveratrol was found significantly effective in decreasing both acrylamide-induced CYP2E1-dependent enzyme activities (approximately 1.5-1.80 fold) and CYP2E1 protein levels (approximately 1.5-1.70 fold). Additionally, resveratrol significantly decreased acrylamide-induced CYP2E1 protein level (2-2.5 fold) in rabbit kidney. However, no significant change was observed in rabbit lung CYP2E1-dependent enzyme activities and CYP2E1 protein levels due to acrylamide, resveratrol or their combined treatments. Furthermore, it was found that acrylamide treatment significantly increased CYP3A6-dependent erythromycin N-demethylase enzyme activity (1.85-fold) and CYP3A6 protein levels in rabbit liver (1.69-fold). No change was observed in CYP2B4-dependent benzphetamine N-demethylase enzyme activities of rabbit liver, kidney and lung by in vivo acrylamide, resveratrol or their combined treatments. Moreover, total GST and GST-Mu activities of rabbit kidney (1.5-fold, respectively) and total GST activity of rabbit lung (1.6-fold) were increased significantly only in resveratrol treated group. NQO1 enzyme activity of rabbit kidney was significantly increased by acrylamide treatment (1.6-fold). The results of the present study have demonstrated for the first time that acrylamide induces rabbit liver and kidney CYP2E1-dependent enzyme activities and CYP2E1 protein levels. The induction of CYP2E1 enzyme activity and protein level by acrylamide treatment can stimulate formation of other toxic compounds and procarcinogens metabolized by CYP2E1 which in turn further potentiates the risk of hepatotoxicity, mutagenicity and carcinogenicity. In the present study, it was also demonstrated for the first time that acrylamide treatment also increases CYP3A6 enzyme activity in rabbit liver which may lead to alterations in drug metabolism. The results of this study have also suggested that resveratrol may have protective effects on acrylamide induced toxicity / however, further in vivo studies are required to clarify the effect of resveratrol on both acrylamide-induced toxicity and anti-oxidant enzymes.
20

The influence of alcohol on acetaminophen hepatotoxicity : CYP2E1 induction and selective mitochondrial glutathione depletion /

Zhao, Ping, January 2002 (has links)
Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 117-125).

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