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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.
1

Roles of mitochondria in the multidrug resistance in R-HepG2 cells. / CUHK electronic theses & dissertations collection

January 2002 (has links)
by Li Yanchun. / "August 2000." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 193-213). / 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.
2

A study of multi-drug efflux pumps in acinetobacter.

January 2003 (has links)
Chau Sze-lok. / Thesis submitted in: December 2002. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 221-245). / Abstracts in English and Chinese. / ABSTRACT (English) --- p.i / ABSTRACT (Chinese) --- p.iii / ACKNOWLEDGMENT --- p.v / LIST OF CONTENTS --- p.vii / LIST OF TABLES --- p.xiv / LIST OF FIGURES --- p.xvii / ABBREVIATIONS --- p.xx / TERMS --- p.xxi / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / (PART A) / Chapter 1.1 --- Acinetobacter spp --- p.1 / Chapter 1.2 --- Clinical importance of Acinetobacter --- p.4 / Chapter 1.3 --- Resistance mechanisms / Chapter 1.3.1 --- Intrinsic resistance --- p.7 / Chapter 1.3.2 --- Acquired resistance --- p.15 / Chapter 1.4 --- Resistance in Acinetobacter --- p.21 / Chapter 1.4.1 --- The efflux system in Acinetobacter --- p.22 / Chapter 1.4.2 --- Other antibiotic resistance mechanisms in Acinetobacter --- p.23 / (PART B) / Chapter 1.5 --- Methods used in this study --- p.29 / Chapter 1.6 --- Rationale of this study --- p.35 / Chapter 1.7 --- Objectives --- p.37 / Chapter CHAPTER 2 --- MATERIALS AND METHODS --- p.39 / Chapter 2.1 --- Bacterial strains and isolates / Chapter 2.1.1 --- Isolates for studying blaIMP-4 --- p.39 / Chapter 2.1.2 --- Isolates for studying adeB --- p.39 / Chapter 2.1.3 --- Isolates for investigation of other efflux pump(s)in Acinetobacter GDG3 --- p.40 / Chapter 2.1.4 --- Isolates for studying the distribution of efflux pumps --- p.40 / Chapter 2.1.5 --- Reference strains --- p.41 / Chapter 2.2 --- Materials / Chapter 2.2.1 --- Sources of materials --- p.42 / Chapter 2.2.2 --- Buffers and solutions --- p.45 / Chapter 2.3 --- Instruments and software --- p.46 / Chapter 2.4 --- General bacteriological techniques / Chapter 2.4.1 --- Bacteriological dientification --- p.47 / Chapter 2.4.2 --- Stock isolates --- p.48 / Chapter 2.4.3 --- Retrieval of isolates --- p.48 / Chapter 2.5 --- General molecular biology techniques / Chapter 2.5.1 --- Agarose gel electrophoresis --- p.49 / Chapter 2.5.2 --- Polymerase chain reaction (PCR) --- p.50 / Chapter 2.5.3 --- Amplified Ribosomal Restriction DNA Analysis (ARDRA) --- p.51 / Chapter 2.5.4 --- Pulsed field gel electrophoresis (PFGE) --- p.53 / Chapter 2.5.5 --- Minimal inhibitory concentration (MIC) --- p.55 / Chapter 2.5.6 --- Antibiotic sensitivity test - disc diffusion test --- p.56 / Chapter 2.5.7 --- Detection of the presence of the common resistance mechanisms --- p.57 / Chapter 2.5.8 --- TA Cloning --- p.60 / Chapter 2.5.9 --- DNA Sequencing --- p.62 / Chapter 2.5.10 --- Sequence analysis --- p.64 / Chapter 2.5.11 --- CYBR Green Assay --- p.65 / Chapter 2.5.12 --- Complementary DNA (cDNA) preparation --- p.66 / Chapter 2.5.13 --- Real time RT-PCR --- p.67 / Chapter 2.5.14 --- Construction of Genome Walker Libraries --- p.69 / Chapter 2.6 --- "Selection of acinetobacters from ICU, blood culture and other clinical isolates" / Chapter 2.6.1 --- Isolates from existing stock cultures --- p.71 / Chapter 2.6.2 --- New isolates obtained for this study --- p.71 / Chapter 2.7 --- Study of expression level of the blaIMP-4 gene / Chapter 2.7.1a --- Verification of the specificity of primers for blaIMP-4 --- p.72 / Chapter 2.7.1b --- Verfication of the specificity of primers for 16S rRNA gene --- p.73 / Chapter 2.7.1c --- Construction of standard curve --- p.76 / Chapter 2.7.2 --- Expression levels of blaIMP-4 and meropenem MICin blaIMP-4+ blood culture isolates --- p.77 / Chapter 2.7.3 --- Intra-assay reproducibility --- p.11 / Chapter 2.7.4 --- Detection of the production of metallo-β-lactamase --- p.77 / Chapter 2.8 --- Study of adeABC expression / Chapter 2.8.1 --- Determination of the presence of the adeB gene --- p.78 / Chapter 2.8.2 --- Entirety of the adeABC operon --- p.79 / Chapter 2.8.3 --- Expression level of the adeB gene --- p.82 / Chapter 2.8.4 --- Expression levels of adeB in sets of serial isolates --- p.84 / Chapter 2.8.5 --- Intra-assay reproducibility --- p.84 / Chapter 2.8.6 --- Inter-assay reproducibility --- p.84 / Chapter 2.9 --- Investigation of other efflux pumps in acinetobacter genomic DNA group3 / Chapter 2.9.1 --- Detection of adeB homologue in a genomic DNA group 3isolate --- p.85 / Chapter 2.9.2 --- Chromosome walking of the adeB-like genes --- p.87 / Chapter 2.9.3 --- Sequences of AdeE and AdeY and their comparison --- p.105 / Chapter 2.9.4 --- Topology prediction of AdeE and AdeY --- p.105 / Chapter 2.9.5 --- The role of the putative pump AdeE --- p.106 / Chapter 2.10 --- Distribution of AdeB and the putative efflux pumps AdeE and AdeY in acinetobacters from different bacterial collections / Chapter 2.10.1 --- Distribution of adeB and the putative pumps (adeE and adeY) in blood cultures (1997-2000) --- p.113 / Chapter 2.10.2 --- Confirmation of the identity of the amplification products of adeE and ade Y in blood culture isolate (1997-2000) --- p.115 / Chapter 2.10.3 --- The presence of adeE in GDG 3 acinetobacters from different sources --- p.116 / Chapter 2.10.4 --- "The presence of adeB, adeE and adeY in antibiotic susceptibility" --- p.116 / Chapter 2.10.5 --- "adeB, adeE and adeY and the clonally and epidemiologically related sets of isolates" --- p.116 / Chapter 2.10.6 --- "adeB, adeE and adeY and the blaIMP-4+ isolates" --- p.116 / Chapter CHAPTER 3 --- "SELECTION OF ACINETOBACTERS FROM ICU, BLOOD CULTURE AND OTHER CLINICAL ISOLATES" --- p.119 / Chapter 3.1 --- Results / Chapter 3.1.1 --- Isolates from existing stock cultures --- p.119 / Chapter 3.1.2 --- New isolates obtained for this study --- p.127 / Chapter 3.2 --- Discussion / Chapter 3.2.1 --- Identification of clonally related isolates by PFGE --- p.129 / Chapter 3.2.2 --- Correlation between the presence of common resistance mechanisms and the changes in antimicrobial susceptibility --- p.129 / Chapter 3.2.3 --- Development of resistance in serial isolates --- p.131 / Chapter CHAPTER 4 --- STUDY OF blaIMP-4 EXPRESSION --- p.133 / Chapter 4.1 --- Results / Chapter 4.1.1 --- Study of expression level of the blaIMP-4 gene --- p.134 / Chapter 4.1.2 --- Expression levels of blaIMP-4 and meropenem MIC in blaIMP-4+ blood culture isolates --- p.136 / Chapter 4.1.3 --- Intra-assay reproducibility \ --- p.37 / Chapter 4.1.4 --- Detection of the production of metallo-β-lactamase --- p.140 / Chapter 4.2 --- Discussion / Chapter 4.2.1 --- Dissociation curve --- p.140 / Chapter 4.2.2 --- Reproducibility of real time RT-PCR --- p.140 / Chapter 4.2.3 --- Relationship between mRNA level of blaIMP-4 and the meropenem MIC --- p.142 / Chapter CHAPTER 5 --- STUDY OF adeABC EXPRESSION --- p.145 / Chapter 5.1 --- Results / Chapter 5.1.1 --- Determination of the presence of the adeB gene --- p.145 / Chapter 5.1.2 --- Entirety of the adeABC operon --- p.146 / Chapter 5.1.3 --- Expression level of the adeB gene --- p.148 / Chapter 5.1.4 --- Expression levels of adeB in sets of serial isolates --- p.151 / Chapter 5.1.5 --- Intra-assay reproducibility --- p.154 / Chapter 5.1.6 --- Inter-assay reproducibility --- p.154 / Chapter 5.2 --- Discussion / Chapter 5.2.1 --- Detection of adeB --- p.156 / Chapter 5.2.2 --- Entirety of the adeABC operon --- p.156 / Chapter 5.2.3 --- Reproducibility of real time RT-PCR --- p.157 / Chapter 5.2.4 --- Relationship between adeB-mRNA level and antimicrobial susceptibility --- p.157 / Chapter CHAPTER 6 --- INVESTIGATION OF OTHER EFFLUX PUMPS IN ACINETOBACTER GENOMIC DNA GROUP3 --- p.159 / Chapter 6.1 --- Results / Chapter 6.1.1 --- Detection of adeB homologue in a genomic DNA group3 isolate --- p.159 / Chapter 6.1.2 --- Chromosome walking of the adeB-like genes --- p.162 / Chapter 6.1.3 --- Sequences of AdeE and AdeY and their comparison --- p.173 / Chapter 6.1.4 --- Topology prediction of AdeE and AdeY --- p.175 / Chapter 6.1.5 --- The role of the putative pump AdeE --- p.177 / Chapter 6.2 --- Discussion / Chapter 6.2.1 --- The AdeE RND transporter --- p.181 / Chapter 6.2.2 --- The theoretical AdeY protein --- p.183 / Chapter CHAPTER 7 --- DISTRIBUTION OF AdeB AND THE PUTATIVE EFFLUX PUMPS AdeE and AdeY IN ACINETOBACTERS FROM DIFFERENT BACTERIAL COLLECTIONS --- p.184 / Chapter 7.1 --- Results / Chapter 7.1.1 --- Distribution of adeB and the putative pumps (adeE and ade Y) in blood cultures (1997-2000) --- p.184 / Chapter 7.1.2 --- Confirmation of the identity of the amplification products of adeE and adeY in blood culture isolates (1997-2000) --- p.187 / Chapter 7.1.3 --- The presence of adeE in GDG 3 acinetobacters from different sources --- p.195 / Chapter 7.1.4 --- "The presence of adeB, adeE and ade Y in antibiotic susceptibility" --- p.196 / Chapter 7.1.5 --- "adeB, adeE and adeY and the clonally and epidemiologically related sets of isolates" --- p.202 / Chapter 7.1.6 --- "adeB, adeE and adeY and the blaIMP-4+ isolates" --- p.202 / Chapter 7.2 --- Discussion / Chapter 7.2.1 --- PCR-RFLP typing --- p.205 / Chapter 7.2.2 --- Distribution of adeB --- p.205 / Chapter 7.2.3 --- Distribution of adeE --- p.206 / Chapter 7.2.4 --- Distribution of adeY --- p.207 / Chapter 7.2.5 --- Distribution of adeE and adeY in GDG 3 isolates --- p.207 / Chapter CHAPTER 8 --- GENERAL DISCUSSION --- p.209 / Chapter 8.1 --- Significance of adeB and the putative pumps (adeE and adeY) --- p.211 / Chapter CHAPTER 9 --- CONCLUSION --- p.218 / Chapter 9.1 --- Conclusion --- p.218 / Chapter 9.2 --- Future Plan --- p.219 / REFERENCES --- p.221 / APPENDIX --- p.246 / Appendix1 --- p.246 / Appendix2 --- p.247 / Appendix3 --- p.252 / Appendix4 --- p.253 / Appendix5 --- p.259
3

Effects of arsenic trioxide on human hepatoma cells.

January 2001 (has links)
Siu Pak-yan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 158-174). / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abstract --- p.ii / 摘要 --- p.iv / Contents --- p.vi / List of Figures and Tables --- p.xiii / List of Abbreviations --- p.xviii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Characteristics of Arsenic Compound --- p.1 / Chapter 1.1.1 --- Arsenic Compounds are Used as Poison --- p.1 / Chapter 1.1.2 --- Arsenic Compounds are Used as Medicine --- p.2 / Chapter 1.2 --- Arsenic Trioxide is a Traditional Chinese Medicine --- p.3 / Chapter 1.3 --- Properties of Arsenic Trioxide --- p.5 / Chapter 1.4 --- Use of Arsenic Trioxide in Cancer Treatment --- p.7 / Chapter 1.4.1 --- Arsenic Trioxide as a Therapeutic Agent in the Treatment of Acute Promyelocytic Leukemia --- p.7 / Chapter 1.4.1.1 --- Characteristics of Acute Promyelocytic Leukemia --- p.7 / Chapter 1.4.1.2 --- Treatment of Acute Promyelocytic Leukemia with All-Trans Retinoic Acid --- p.10 / Chapter 1.4.1.3 --- Treatment of Acute Promyelocytic Leukemia with Arsenic Trioxide --- p.11 / Chapter 1.4.1.4 --- Action Mechanism of Arsenic Trioxide --- p.13 / Chapter 1.4.2 --- Arsenic Trioxide as a Therapeutic Agent in the Treatment of Non-APL Leukemia --- p.15 / Chapter 1.4.3 --- Arsenic Trioxide as a Therapeutic Agent in the Treatment of Solid Tumors --- p.16 / Chapter 1.5 --- Human Hepatocellular Carcinoma --- p.16 / Chapter 1.5.1 --- The Incidence of Liver Cancer --- p.16 / Chapter 1.5.2 --- Classification of Liver Cancer --- p.17 / Chapter 1.6 --- Aim of the Project --- p.17 / Chapter 1.6.1 --- In Vitro Study of the Effect of Arsenic Trioxide on HepG2 Cells --- p.19 / Chapter 1.6.2 --- In Vivo Study of the Effect of Arsenic Trioxide by Tumor-Bearing Nude Mice Model --- p.20 / Chapter 1.6.3 --- "In Vitro Study of the Effect of Arsenic Trioxide on Multidrug-Resistant Human Hepatocellular Carcinoma Cell Line, R-HepG2" --- p.22 / Chapter Chapter 2 --- Materials and Methods / Chapter 2.1 --- Materials --- p.24 / Chapter 2.1.1 --- Cell Lines and Culture Medium --- p.24 / Chapter 2.1.1.1 --- Cell Lines --- p.24 / Chapter 2.1.1.2 --- Culture Medium --- p.25 / Chapter 2.1.2 --- Chemicals --- p.26 / Chapter 2.1.3 --- Reagents and Buffers --- p.27 / Chapter 2.1.3.1 --- Phosphate Buffered Saline (PBS) --- p.27 / Chapter 2.1.3.2 --- "3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) Solution" --- p.27 / Chapter 2.1.3.3 --- Reagents for DNA Fragmentation Assay --- p.21 / Chapter 2.1.3.3.1 --- DNA Lysis Buffer --- p.27 / Chapter 2.1.3.3.2 --- Tris-EDTA (TE) Buffer --- p.27 / Chapter 2.1.3.3.3 --- Tris-Acetate (TAE) Buffer --- p.28 / Chapter 2.1.3.3.4 --- Proteinase K and Ribonuclease A (RNase A) --- p.28 / Chapter 2.1.3.3.5 --- 6X DNA Loading Dye --- p.28 / Chapter 2.1.3.3.6 --- One Hundred Base-Pair DNA Ladder --- p.28 / Chapter 2.1.3.4 --- Reagents for Western Blot Analysis --- p.29 / Chapter 2.1.3.4.1 --- SDS Lysis Buffer --- p.29 / Chapter 2.1.3.4.2 --- 4X Lower Gel Buffer --- p.29 / Chapter 2.1.3.4.3 --- 4X Upper Gel Buffer --- p.29 / Chapter 2.1.3.4.4 --- 10X SDS Running Buffer --- p.29 / Chapter 2.1.3.4.5 --- 2X SDS Sample Loading Dye --- p.30 / Chapter 2.1.3.4.6 --- Electroblotting Buffer --- p.30 / Chapter 2.1.3.4.7 --- Tris-Buffered Saline with 01% Tween-20 (TBS-T) --- p.30 / Chapter 2.1.3.4.8 --- Lysis Buffer for Detection of the Release of Cytochrome C --- p.31 / Chapter 2.1.3.5 --- Propidium Iodide (PI) --- p.31 / Chapter 2.1.3.6 --- "5,5 ´ة,6,6´ة-tetrachloro-1,1',3,3 '-tetraethylbenzimidazolyl carbocyanine Iodide (JC-1)" --- p.31 / Chapter 2.1.3.7 --- Reagents for In Vivo Study --- p.32 / Chapter 2.1.3.7.1 --- Saline --- p.32 / Chapter 2.1.3.7.2 --- Homogenizing Buffer --- p.32 / Chapter 2.1.3.7.3 --- 10% Buffered Formalin --- p.32 / Chapter 2.1.3.7.4 --- Acid Alcohol --- p.32 / Chapter 2.1.3.7.5 --- Scott's Tap Water --- p.32 / Chapter 2.1.3.7.6 --- 0.5% Aqueous Eosin --- p.33 / Chapter 2.2 --- Methods --- p.33 / Chapter 2.2.1 --- MTT Assay --- p.33 / Chapter 2.2.2 --- Trypan Blue Exclusion Assay --- p.34 / Chapter 2.2.3 --- Analysis of Cell-Cycle Phase Distribution by Flow Cytometry with PI Staining --- p.34 / Chapter 2.2.4 --- DNA Fragmentation Assay --- p.35 / Chapter 2.2.5 --- Quantification of Apoptosis by Flow Cytometry with Annexin V-PI Staining --- p.36 / Chapter 2.2.6 --- Assessment of the Change in Mitochondrial Membrane Potential (ΔΦm) --- p.37 / Chapter 2.2.7 --- Western Analysis --- p.38 / Chapter 2.2.8 --- Glucose Uptake Assay --- p.40 / Chapter 2.2.9 --- ATP Production Assay --- p.41 / Chapter 2.2.10 --- In Vivo Study --- p.44 / Chapter 2.2.10.1 --- Animal Model --- p.44 / Chapter 2.2.10.2 --- Cell Line --- p.44 / Chapter 2.2.10.3 --- Treatment with Arsenic Trioxide --- p.44 / Chapter 2.2.10.4 --- Assessment of the Anti-Cancer Activity of Arsenic Trioxide --- p.45 / Chapter 2.2.10.5 --- Tissue Sample Preparation --- p.45 / Chapter 2.2.10.5.1 --- Preparation of Plasma --- p.45 / Chapter 2.2.10.5.2 --- Preparation of Liver Tissue Homogenate --- p.46 / Chapter 2.2.10.5.3 --- Preparation of Cytosolic Fraction --- p.46 / Chapter 2.2.10.6 --- Measurement of the Plasma Enzyme Activity --- p.46 / Chapter 2.2.10.6.1 --- "Plasma Creatine Kinase (CK) Activity, Plasma Lactate Dehydrogenase (LDH) Activity, Plasma Alanine Transaminase (ALT) Activity and Plasma Asparate Transaminase (AST) Activity" --- p.46 / Chapter 2.2.10.7 --- Preparation of Tissue for Light Microscopic Study --- p.48 / Chapter 2.2.10.8 --- Measurement of the Basal Reduced Glutathione (GSH) Level of Liver Tissue --- p.51 / Chapter 2.2.10.9 --- "Measurement of the Activity of Antioxidant Enzyme, Glutathione S-Transferase (GST) of Liver Tissue" --- p.53 / Chapter 2.3 --- Statistical Analysis --- p.54 / Chapter Chapter 3 --- "In Vitro Study of Arsenic Trioxide on Acute Promyelocytic Leukemia Cell Line, NB-4" / Chapter 3.1 --- Introduction --- p.55 / Chapter 3.2 --- Principle of Flow Cytometry with Annexin V-PI Staining --- p.56 / Chapter 3.3 --- The Effect of Arsenic Trioxide on Cell Proliferation of NB-4 Cells --- p.59 / Chapter 3.4 --- Study of the Action Mechanism of Arsenic Trioxide upon Treatment of NB-4 Cells --- p.61 / Chapter 3.5 --- Summary --- p.63 / Chapter Chapter 4 --- "In Vitro Study of Arsenic Trioxide on Human Hepatocellular Carcinoma Cell Line, HepG2" / Chapter 4.1 --- Introduction --- p.64 / Chapter 4.2 --- The Effect of Arsenic Trioxide on Cell Proliferation of HepG2 Cells by MTT Assay --- p.66 / Chapter 4.3 --- The Effect of Arsenic Trioxide on HepG2 Cells at Clinically Achievable Concentration --- p.68 / Chapter 4.3.1 --- The Cytotoxicity of Arsenic Trioxide on HepG2 Cells by Trypan Blue Exclusion Assay --- p.68 / Chapter 4.3.2 --- The Effect of Arsenic Trioxide on Cell-Cycle Phase Distribution --- p.71 / Chapter 4.3.3 --- The Underlying Mechanism of the Cytotoxic Effect of Arsenic Trioxide 一 Necrosis or Apoptosis? --- p.74 / Chapter 4.3.3.1 --- DNA Fragmentation Assay --- p.74 / Chapter 4.3.3.2 --- Flow Cytometry with Annexin V-PI Staining --- p.76 / Chapter 4.3.3.3 --- Brief Conclusion --- p.78 / Chapter 4.3.4 --- The Study of the Mechanism of Apoptotic Pathway --- p.78 / Chapter 4.3.4.1 --- Activation of Caspase-3 upon Arsenic Trioxide Treatment --- p.79 / Chapter 4.3.4.2 --- The Participation of Mitochondria in Arsenic Trioxide-Induced Apoptosis --- p.81 / Chapter 4.3.4.2.1 --- The Change in Mitochondrial Membrane Potential upon Arsenic Trioxide Treatment --- p.81 / Chapter 4.3.4.2.2 --- The Study of the Release of Cytochrome C from the Mitochondria to Cytosol upon Treatment with Arsenic Trioxide --- p.85 / Chapter 4.3.4.2.3 --- Brief Conclusion --- p.87 / Chapter 4.4 --- Arsenic Trioxide Mediated Its Effect via Other Action Mechanisms --- p.87 / Chapter 4.4.1 --- The Effect of Arsenic Trioxide on the Expression of Glucose Transporters 1 and2 --- p.88 / Chapter 4.4.2 --- The Effect of Arsenic Trioxide on Glucose Uptake --- p.91 / Chapter 4.4.3 --- The Effect of Arsenic Trioxide on ATP Production --- p.93 / Chapter 4.4.4 --- Brief Conclusion --- p.93 / Chapter 4.5 --- Summary --- p.95 / Chapter Chapter 5 --- In Vivo Study of Arsenic Trioxide on HepG2-Bearing Nude Mice / Chapter 5.1 --- Introduction --- p.96 / Chapter 5.2 --- Treatment with Arsenic Trioxide --- p.97 / Chapter 5.3 --- Assessment of the Anti-Tumor Effect of Arsenic Trioxide --- p.99 / Chapter 5.4 --- The Effect of Arsenic Trioxide toward Normal Tissues --- p.103 / Chapter 5.4.1 --- The Effect of Arsenic Trioxide on Liver --- p.104 / Chapter 5.4.1.1 --- Morphological Study --- p.104 / Chapter 5.4.1.2 --- Enzymatic Study --- p.107 / Chapter 5.4.1.3 --- Brief Conclusion --- p.107 / Chapter 5.4.2 --- The Effect of Arsenic Trioxide on Heart --- p.110 / Chapter 5.4.2.1 --- Morphological Study --- p.110 / Chapter 5.4.2.2 --- Enzymatic Study --- p.112 / Chapter 5.4.2.3 --- Brief Conclusion --- p.112 / Chapter 5.5 --- Involvement of the Glutathione Redox System --- p.115 / Chapter 5.5.1 --- Basal GSH Level --- p.115 / Chapter 5.5.2 --- The Activity of Glutathion S-Transferase --- p.117 / Chapter 5.5.3 --- Brief Conclusion --- p.117 / Chapter 5.6 --- Summary --- p.120 / Chapter Chapter 6 --- "In Vitro Study of Arsenic Trioxide on Multidrug-Resistant Human Hepatocellular Carcinoma Cell Line, R-HepG2" / Chapter 6.1 --- Introduction --- p.121 / Chapter 6.2 --- The Effect of Doxorubicin on the Parental HepG2 Cells and R-HepG2 Cells by MTT Assay --- p.123 / Chapter 6.3 --- The Effect of Arsenic Trioxide on Cell Proliferation of R-HepG2 Cells by MTT Assay --- p.126 / Chapter 6.4 --- The Effect of Arsenic Trioxide on Cell-Cycle Phase Distribution of R-HepG2 Cells --- p.129 / Chapter 6.5 --- Trioxide on R-HepG2 Cells ´ؤ Necrosis or Apoptosis? --- p.131 / Chapter 6.5.1 --- DNA Fragmentation Assay --- p.131 / Chapter 6.5.2 --- Flow Cytometry with Annexin V-PI Staining --- p.133 / Chapter 6.5.3 --- Brief Conclusion --- p.133 / Chapter 6.6 --- Examination of the Probable Involvement of Arsenic Trioxide as a Substrate of P-Glycoprotein --- p.135 / Chapter 6.7 --- Summary --- p.137 / Chapter Chapter 7 --- Discussion / Chapter 7.1 --- The Significance of the Study of Arsenic Trioxide in the Treatment of Arsenic Trioxide --- p.138 / Chapter 7.2 --- Comparison of Preparation of Drug in Present Study with Others --- p.140 / Chapter 7.3 --- Effect of Arsenic Trioxide on Human Hepatocellular Carcinoma --- p.142 / Chapter 7.4 --- Mechanism Study of Arsenic Trioxide --- p.142 / Chapter 7.5 --- Dosage of Arsenic Trioxide Used in In Vivo Study --- p.152 / Chapter 7.6 --- Cytotoxicity of Arsenic Trioxide toward Normal Tissues --- p.153 / Chapter 7.7 --- "Effect of Arsenic Trioxide on Multidrug-Resistant Human Hepatocellular Carcinoma Cell Line, R-HepG2" --- p.154 / Chapter 7.8 --- Conclusions and Future Prospect --- p.156 / Chapter Chapter 8 --- References / Chapter 8.1 --- English References --- p.158 / Chapter 8.2 --- Chinese References --- p.174 / Chapter 8.3 --- Online References --- p.174
4

Modulação do fenótipo de resistência a múltiplas drogas por lipoproteínas em células de sarcoma uterino resistente à doxorrubicina / Modulation of phenotype of multidrug resistance for lipoprotein in uterine sarcoma cells resistant to doxorubicin

Celestino, Andrea Turbuck 24 February 2010 (has links)
O desenvolvimento de resistência a múltiplas drogas na terapêutica do câncer é um importante obstáculo para o tratamento efetivo. Os mecanismos de resistência a múltiplas drogas ocasionam a redução intracelular de agentes quimioterápicos e, por conseqüência, estão envolvidos no fracasso no tratamento do câncer. Os principais genes envolvidos neste fenômeno são: o gene MDR1(multiple drug resisctance), que codifica uma glicoproteína de alto peso molecular, a P-gp; o gene MRP1, que codifica uma glicoproteína de 190 Kda, denominada proteína associada à resistência a múltiplas drogas; e o gene da LRP (proteína relacionada à resistência de pulmão). Alguns estudos sugerem que o colesterol pode estar envolvido diretamente com o fenômeno de resistência a múltiplas drogas, e que os lipídeos podem influenciar várias e complexas funções no MDR, por afetarem o transporte de drogas através da membrana plasmática. Além disso, células tumorais tem maior necessidade de colesterol devido a uma taxa de multiplicação mais elevada que as células normais. Neste estudo analisou-se a expressão dos genes MDR1, MRP1 e LRP em células de sarcoma uterino resistentes à doxorrubicina, e a influência de lipoproteínas. Houve aumento da expressão dos genes MDR1, MRP1 e LRP nas células tratadas com a LDL, sendo mais expressivo o gene MDR1. A HDL diminuiu a expressão dos genes MRP1 e LRP. No entanto, o gene MDR1 teve sua expressão diminuída somente em concentrações maiores. As células cultivadas em meio sem soro fetal apresentaram um elevado aumento na expressão destes genes. Em conclusão, as lipoproteínas podem modular a expressão dos genes MDR1, MRP1 e LRP e, assim, atuar na resistência a múltiplas drogas. / The development of multidrug resistance in anticancer therapy is an obstacle in the efficiency of the treatment. The multidrug resistance mechanism causes reduction of intracellular chemotherapeutical drugs. Therefore, it leads to treatment failure. There are three main multidrug resistance genes: MDR1, which codifies the P-gp (a high weight glycoprotein); MRP1, which codifies a 190 Kda glycoprotein; and, the LRP (lung resistance related protein) gene. Several reports suggest that cholesterol may be directly involved with the multidrug resistance phenomenon and that lipids may affect many complex functions in this regard, as the activity of the drug transport across the plasmatic membrane. Moreover, tumor cells have great cholesterol necessity due to the high cell multiplication rate. Here we described the MDR, MRP, LRP gene expression of a doxorubicin-resistant uterine sarcoma cell line under the influence of lipoproteins. LDL increased the expression of all genes, mainly MDR1. Treatment with HDL led to reduction of MRP and LRP expression. However, the MDR gene expression decreased only by higher concentrations of HDL. Cells grown in serumdeprived medium led to an increased expression of all the studied genes. Therefore, lipoproteins may modulate the MDR, MRP, LRP gene expression and, consequently, the cell resistance to drugs.
5

Reversal of multidrug resistance by novel polyoxypregnane compounds.

January 2011 (has links)
Chai, Stella. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 108-126). / Abstracts in English and Chinese. / ABSTRACT --- p.i / 論文摘要 --- p.iii / ACKNOWLEDGEMENTS --- p.v / PATENT AND PUBLICAION --- p.vii / CONFERENCE ABSTRACTS AND PRESENTATIONS --- p.viii / AWARDS --- p.ix / ABBREVIATIONS --- p.x / LIST OF TABLES --- p.xii / LIST OF FIGURES --- p.xiv / TABLE OF CONTENT --- p.xviii / Chapter CHAPTER 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Multidrug resistance (MDR) --- p.1 / Chapter 1.1.1 --- Cancer --- p.1 / Chapter 1.1.2 --- Mechanisms of MDR in cancer --- p.1 / Chapter 1.1.2.1 --- Drug entry --- p.3 / Chapter 1.1.2.2 --- Drug metabolism --- p.3 / Chapter 1.1.2.3 --- Drug sequestration --- p.4 / Chapter 1.1.2.4 --- Mechanisms activated after nuclear entry --- p.5 / Chapter 1.1.2.5 --- Evasion of drug-induced apoptosis --- p.5 / Chapter 1.1.3 --- Approaches in treating MDR --- p.5 / Chapter 1.1.3.1 --- Overcoming MDR by inhibiting transporters --- p.6 / Chapter 1.1.3.2 --- Overcoming MDR by altering signaling pathway --- p.6 / Chapter 1.1.4 --- ATP Binding Cassette (ABC) Transporters --- p.7 / Chapter 1.1.4.1 --- P-glycoprotein (P-gp) --- p.7 / Chapter 1.1.4.2 --- Multidrug resistance-associated protein 1 (MRP 1) --- p.9 / Chapter 1.1.4.3 --- Breast cancer resistant protein (BCRP) --- p.10 / Chapter 1.1.4.4 --- ABC drug transporters and drug absorption --- p.11 / Chapter 1.2 --- The Use of Traditional Chinese Medicine (TCM) in circumventing P-gp-mediated MDR --- p.12 / Chapter 1.2.1 --- Active ingredients in TCM - Alkaloid --- p.12 / Chapter 1.2.2 --- Active ingredients in TCM - Saponin --- p.14 / Chapter 1.2.3 --- Active ingredients in TCM - Flavonoid --- p.15 / Chapter 1.2.4 --- Active ingredients in TCM - Others --- p.17 / Chapter 1.3 --- Polyoxypregnane compounds (POPs) --- p.17 / Chapter 1.3.1 --- Characterization --- p.17 / Chapter 1.3.2 --- POPs isolated from M. tenacissima --- p.18 / Chapter 1.4 --- Objectives of Current Study --- p.22 / Chapter CHAPTER 2. --- EFFECTS OF POLYOXYPREGNANE COMPOUNDS ON VIABILITY AND PROLIFERATION OF HUMAN RESISTANT CANCER CELLS --- p.24 / Chapter 2.1 --- Materials and Methods --- p.25 / Chapter 2.1.1 --- "Chemicals, Materials and Reagents" --- p.25 / Chapter 2.1.2 --- Methods --- p.26 / Chapter 2.1.2.1 --- Cell Lines and Cell Culture --- p.26 / Chapter 2.1.2.2 --- Preparation of POPs --- p.27 / Chapter 2.1.2.3 --- Sulforhodamine B assay --- p.27 / Chapter 2.1.2.4 --- Statistical analysis --- p.29 / Chapter 2.2 --- Results --- p.29 / Chapter 2.2.1 --- Effects of POPs on the viability of parental SW620 and P-gp-overexpressing resistant SW620/Ad300 cells --- p.29 / Chapter 2.2.2 --- Effects of POPs on the viability of parental MCF-7 and MRP1-overexpressing resistant MCF-7/VP cells --- p.33 / Chapter 2.2.3 --- Effects of POPs on the viability of parental MCF-7 and ABCG2-overexpressing resistant MCF-7/FLV1000 cells --- p.37 / Chapter 2.3 --- Discussion --- p.41 / Chapter 2.3.1 --- Structure activity relationship (SAR) --- p.43 / Chapter 2.3.2 --- Nine compounds relating to P-gp-mediated MDR --- p.46 / Chapter CHAPTER 3. --- MECHANISM OF NINE SELECTED POPS IN MODULATING P-GP-MEDIATED MDR --- p.49 / Chapter 3.1 --- Materials and Methods --- p.49 / Chapter 3.1.1 --- "Chemicals, Materials and Reagents" --- p.49 / Chapter 3.1.2 --- Methods --- p.53 / Chapter 3.1.2.1 --- Cell Lines and Cell Culture --- p.53 / Chapter 3.1.2.2 --- Extraction of nine POPs from M. tenacissima --- p.54 / Chapter 3.1.2.3 --- Sulforhodamine B (SRB) assay --- p.55 / Chapter 3.1.2.4 --- Flow cytometry assay --- p.55 / Chapter 3.1.2.5 --- P-gp ATPase assay --- p.56 / Chapter 3.1.2.6 --- Immuno-blot/Western blot analysis --- p.58 / Chapter 3.1.2.7 --- Reverse transcription and quantitative real-time PCR --- p.59 / Chapter 3.1.2.8 --- Statistical analysis --- p.60 / Chapter 3.2 --- Results --- p.60 / Chapter 3.2.1 --- Effects of nine selected POPs on the viability of sensitive human breast cancer MCF-7 cells --- p.60 / Chapter 3.2.2 --- Effects of nine selected POPs on the viability of MDR 1 -transfected HEK1 MDR1 cell line and its control vector transfected cell line HEK293 pcDNA3 --- p.61 / Chapter 3.2.3 --- Effects of nine selected POPs in inhibiting efflux of P-gp substrate --- p.64 / Chapter 3.2.4 --- Effects of nine selected POPs in modulating P-gp ATPase activity --- p.68 / Chapter 3.2.5 --- Effects of nine selected POPs in regulating P-gp protein expression --- p.69 / Chapter 3.2.6 --- MDR1 mRNA expression in various cell lines --- p.72 / Chapter 3.3 --- Discussion --- p.72 / Chapter 3.3.1 --- Effective POPs are targeting specifically P-gp overexpression --- p.73 / Chapter 3.3.2 --- Mechanistic understanding the circumvention of MDR by the effective POPs --- p.74 / Chapter 3.3.2.1 --- Relative potency for the reversal of P-gp-mediated MDR --- p.75 / Chapter 3.3.2.2 --- Inhibition of P-gp-mediated drug efflux across cell membrane by the effective POPs --- p.75 / Chapter 3.3.2.3 --- Stimulation of ATPase by the effective POPs --- p.76 / Chapter 3.3.2.4 --- No effect of POPs on the alteration of P-gp expression --- p.77 / Chapter 3.3.2.5 --- An overall summary of the mechanism of MDR reversal by the effective POPs --- p.78 / Chapter 3.3.3 --- Implication in drug disposition and drug-drug interactions --- p.79 / Chapter 3.3.4 --- Additional information for the structure activity relationship (SAR) --- p.80 / Chapter CHAPTER 4. --- EFFECTS OF CRUDE EXTRACT AND THREE MAJOR POLYOXYPREGNANES (POPS) OF MARS DEN I A TENACISSIMA --- p.81 / Chapter 4.1 --- Materials and Methods --- p.82 / Chapter 4.1.1 --- "Chemicals, Materials and Reagents" --- p.82 / Chapter 4.1.2 --- Methods --- p.82 / Chapter 4.1.2.1 --- "Preparation of M. tenacissima extract, artificial mixture and three fractions" --- p.82 / Chapter 4.1.2.2 --- Sulforhodamine B assay --- p.85 / Chapter 4.1.2.3 --- "Biotransformation study of POP68, POP69 and POP70" --- p.85 / Chapter 4.1.2.4 --- HPLC-MS analysis --- p.86 / Chapter 4.1.2.5 --- Animal care and housing conditions --- p.87 / Chapter 4.1.2.6 --- Toxicity studies of fraction 2 in mice --- p.88 / Chapter 4.1.2.7 --- Statistical analysis --- p.89 / Chapter 4.2 --- Results --- p.89 / Chapter 4.2.1 --- "Effects of crude extract, artificial mixture on the viability of sensitive human breast cancer MCF-7 cells" --- p.89 / Chapter 4.2.2 --- "Effects of crude extract, artificial mixture on the viability of sensitive SW620 and P-gp-overexpressing resistant SW620/Ad300 cells" --- p.90 / Chapter 4.2.3 --- "Metabolites of POP68, POP69 and POP70 after incubation with human intestinal microbiota" --- p.91 / Chapter 4.2.4 --- Toxicity of fraction 2 in mice --- p.94 / Chapter 4.3 --- Discussion --- p.98 / Chapter CHAPTER 5. --- FINAL DISCUSSION AND CONCLUSIONS --- p.105 / REFERENCES --- p.108
6

Characterisation of antibiotic-resistant Propionibacterium acnes from acne vulgaris and other diseases /

Oprica, Cristina, January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 5 uppsatser.
7

The identification and distribution of multidrug resistance in Streptococcus pneumoniae in Washington State /

Luna, Vicki Ann, January 1999 (has links)
Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 143-181).
8

Modulação do fenótipo de resistência a múltiplas drogas por lipoproteínas em células de sarcoma uterino resistente à doxorrubicina / Modulation of phenotype of multidrug resistance for lipoprotein in uterine sarcoma cells resistant to doxorubicin

Andrea Turbuck Celestino 24 February 2010 (has links)
O desenvolvimento de resistência a múltiplas drogas na terapêutica do câncer é um importante obstáculo para o tratamento efetivo. Os mecanismos de resistência a múltiplas drogas ocasionam a redução intracelular de agentes quimioterápicos e, por conseqüência, estão envolvidos no fracasso no tratamento do câncer. Os principais genes envolvidos neste fenômeno são: o gene MDR1(multiple drug resisctance), que codifica uma glicoproteína de alto peso molecular, a P-gp; o gene MRP1, que codifica uma glicoproteína de 190 Kda, denominada proteína associada à resistência a múltiplas drogas; e o gene da LRP (proteína relacionada à resistência de pulmão). Alguns estudos sugerem que o colesterol pode estar envolvido diretamente com o fenômeno de resistência a múltiplas drogas, e que os lipídeos podem influenciar várias e complexas funções no MDR, por afetarem o transporte de drogas através da membrana plasmática. Além disso, células tumorais tem maior necessidade de colesterol devido a uma taxa de multiplicação mais elevada que as células normais. Neste estudo analisou-se a expressão dos genes MDR1, MRP1 e LRP em células de sarcoma uterino resistentes à doxorrubicina, e a influência de lipoproteínas. Houve aumento da expressão dos genes MDR1, MRP1 e LRP nas células tratadas com a LDL, sendo mais expressivo o gene MDR1. A HDL diminuiu a expressão dos genes MRP1 e LRP. No entanto, o gene MDR1 teve sua expressão diminuída somente em concentrações maiores. As células cultivadas em meio sem soro fetal apresentaram um elevado aumento na expressão destes genes. Em conclusão, as lipoproteínas podem modular a expressão dos genes MDR1, MRP1 e LRP e, assim, atuar na resistência a múltiplas drogas. / The development of multidrug resistance in anticancer therapy is an obstacle in the efficiency of the treatment. The multidrug resistance mechanism causes reduction of intracellular chemotherapeutical drugs. Therefore, it leads to treatment failure. There are three main multidrug resistance genes: MDR1, which codifies the P-gp (a high weight glycoprotein); MRP1, which codifies a 190 Kda glycoprotein; and, the LRP (lung resistance related protein) gene. Several reports suggest that cholesterol may be directly involved with the multidrug resistance phenomenon and that lipids may affect many complex functions in this regard, as the activity of the drug transport across the plasmatic membrane. Moreover, tumor cells have great cholesterol necessity due to the high cell multiplication rate. Here we described the MDR, MRP, LRP gene expression of a doxorubicin-resistant uterine sarcoma cell line under the influence of lipoproteins. LDL increased the expression of all genes, mainly MDR1. Treatment with HDL led to reduction of MRP and LRP expression. However, the MDR gene expression decreased only by higher concentrations of HDL. Cells grown in serumdeprived medium led to an increased expression of all the studied genes. Therefore, lipoproteins may modulate the MDR, MRP, LRP gene expression and, consequently, the cell resistance to drugs.
9

Caracterização clínica, microbiológica e molecular e tratamento de infecções por enterobactérias resistentes aos carbapenêmicos / Clinical, microbiology and molecular characterization and treatment of infections with carbapenem-resistant Enterobacteriaceae

Carrilho, Cláudia Maria Dantas de Maio 26 March 2015 (has links)
Introdução: Infecções por Enterobactérias resistentes aos carbapenêmicos (ERC), em especial produtoras de Klebsiella pneumoniae carbapenamase tipo KPC hoje são endêmicas em diversas regiões do mundo, seu tratamento é ainda um grande desafio em particular de isolados resistentes à polimixina. Objetivos: Descrever as características clínicas, microbiológicas e moleculares das infecções por ERC. Método: Estudo de coorte prospectiva, realizado no Hospital Universitário de Londrina, Paraná, Brasil, entre março de 2011 a dezembro de 2012. Foram acompanhados pacientes >= 18 anos, que apresentaram infecção por ERC. Dados demográficos e clínicos como idade, sexo, diagnóstico à admissão e presença de co-morbidades de acordo com critérios de Charlson, internação em Unidade de Terapia intensiva e scores APACHE e SOFA desses pacientes, colonização prévia por ERC, cirurgia prévia à infecção, diálise, uso prévio de antimicrobianos e sítio de infecção foram coletados. Foram avaliados os antimicrobianos utilizados para tratamento das infecções por mais de 48 horas nos seguintes pontos: monoterapia ou terapia associada, tempo de início (menor e maior que 12 horas). A identificação do agente foi realizada por método automatizado (Vitek II - bioMerieuxR) e a concentração inibitória mínima dos antibióticos por técnica de microdiluição em caldo, pesquisa de gene blaKPC pela técnica de Polimerase Chain Reaction e sinergismo entre drogas utilizadas em tratamento combinado por meio do método Time Kill. A clonalidade, por Pulsed Field gel eletroforese e analisada por dendograma pelo Bionumerics. Foram realizadas análise bivariada e regressão logística multivariada com técnica de Forward Stepwise para detectar fatores de risco para resistência a polimixina e mortalidade. O nível de significância adotado foi de 5%, utilizando os programas Epi Info 7.0 e SPSS. Resultados: No período de estudo, 127 pacientes apresentaram infecções por ERC, idade média de 55,7 (± 18) anos e 88 (69.3%) do sexo masculino. Infecções de trato respiratório (52-42%) e trato urinário (51 - 40,2%) foram as mais freqüentes, 27 (21,3%) resistentes à polimixina, 113 (89%) das enterobactérias eram K. pneumoniae e 96 (75,6%) tinham gene blaKPC.. Cinquenta e cinco (43,3%) eram polimicrobianas, a maioria (28,3%) co-infecção por Acinetobacter baumannii. A taxa de mortalidade hospitalar foi 61,4%, sendo 34,6% relacionada à infecção e não houve diferença significativa entre os grupos sensíveis (34%) e resistentes à polimixina (37%), p=0.46. Os fatores de risco independentes para óbito foram choque (OR 27.40; IC95% 1.68-446.82; p= 0.02) e diálise (OR 13.26; IC95% 1.17-149.98; p= 0.03); para resistência à polimixina: uso prévio de carbapenem ( OR 2.95; IC95% 1.12-7.78; p= 0.02) e para óbito nessa população: diálise (OR 7,58; IC95% 1,30-43,92; p= 0.02). Terapia combinada, tempo de início de antibiótico sensível e sinergismo in vitro não tiveram impacto significativo na mortalidade. Conclusão: O uso prévio de carbapenêmico foi o único fator associado com a resistência à polimixina nesse estudo. Os fatores associados ao óbito entre os pacientes com infecções por enterobactérias resistentes à polimixina foram fatores de gravidade, como diálise e choque. Nenhuma opção terapêutica, em especial a associação de drogas e nem o tempo de início do tratamento, interferiu na mortalidade deste grupo de pacientes / Introduction: Infections due to Carbapenem resistant Enterobacteriaceae (CRE), particularly Klebsiella pneumoniae producing carbapenemase type KPC, have been endemic in several regions around the world. Their treatment remains a major challenge, particularly for isolates resistant to polymyxin. Objectives: To describe the clinical, microbiological and molecular characteristics of infections by CRE. Methods: Prospective cohort conducted at the University Hospital of Londrina, Paraná, Brazil, from March 2011 to December 2012. All hospitalized patients >= 18 years old who developed infection by CRE were followed until death or discharge. We collected and analyzed the following clinical data: age, sex, diagnosis at admission, presence of comorbidities according to the Charlson criteria, admission in Intensive Care Unit, APACHE and SOFA scores, previous colonization by CRE, previous surgery, dialysis, prior antibiotic use and infection site; furthermore, we also evaluated the time between the blood culture collect and the first antimicrobial dose administration (start time - smaller or longer than 12 hours) as well as whether the treatment was monotherapy or combine therapy for more than 48 hours. The microbiological identification was performed by automated method (Vitek II - bioMerieuxR) and the minimum inhibitory concentration of antibiotics by broth microdilution technique, research blaKPC gene by the technique of Polymerase Chain Reaction and synergism between the drugs used in the combination therapy by Time Kill method. The clonality was carried out by pulsed-field gel electrophoresis and analyzed by dendrogram by BioNumerics. Bivariate analyses and multivariate logistic regression with forward stepwise technique were performed to detect risk factors for resistance to polymyxin and mortality. The level of significance was 5%, using Epi Info 7.0 and SPSS programs. Results: During the study period, 127 patients developed infections by CRE, mean age 55.7 (± 18) years and 88 (69.3%) were male. Respiratory tract infections 52 (42%) and urinary tract 51 (40.2%) were the most frequent. Twenty seven (21.3%) agents were resistant to polymyxin; 113 (89%) were K. pneumoniae and 96 (75.6%) had blaKPC gene. Fifty-five (43.3%) were polymicrobial, the majority (28.3%) co-infection by Acinetobacter baumannii. The hospital mortality rate was 61.4% and 34.6% of the death were related to infection. There was no difference in mortality rate between sensitive (34%) versus resistant (37%)(p = 0.46) to polymyxin. The independent risk factors for death were shock (OR 27.40; 95% CI 1.68-446.82; p = 0.02) and dialysis (OR 13:26; 95% CI 1.17-149.98; p = 0.03); and for resistance to polymyxin were previous use of carbapenem (OR 2.95; 95% CI 1.12-7.78; p = 0.02). The risk factor for death in our study was dialysis (OR 7.58; 95% CI 1.30 to 43.92; p = 0.02). Combine therapy, start time and sensitive and antibiotic synergy in vitro had no significant impact on mortality. Conclusion: In our study, previous carbapenem use was the only factor associated with resistance to polymyxin. Furthermore, dialysis and shock were the only factors associated with death among patients with infections caused by CRE resistant to polymyxin. No therapeutic option, especially the combination of drugs and the start time decreased the higher mortality rates in this group of patients
10

Reversal of multidrug resistance in colon cancer cells by tanshinones: 丹參酮對結腸癌細胞多藥耐藥的逆轉 / 丹參酮對結腸癌細胞多藥耐藥的逆轉 / CUHK electronic theses & dissertations collection / Reversal of multidrug resistance in colon cancer cells by tanshinones: Dan shen tong dui jie chang ai xi bao duo yao nai yao de ni zhuan / Dan shen tong dui jie chang ai xi bao duo yao nai yao de ni zhuan

January 2014 (has links)
Colon cancer, a disease in which malignant tumors form in the tissues of colon, is the first commonest cancer and the second leading cause of cancer-related deaths in Hong Kong. The standard treatment options for colon cancer include surgery and chemotherapy. However, multidrug resistance (MDR) develops in nearly all patients with colon cancer. In fact, most of the cancer-related deaths are due to chemotherapy failure caused by MDR, which occurs during the course of cancer progression and chemotherapy. Thus, the reversal of MDR plays an important role in the successful chemotherapy for colon cancer. This study investigated such a pharmacological action in reversing MDR in colon cancer cells by tanshinones, targeting the two common mechanisms responsible for MDR, i.e. overexpression of ATP-binding cassette (ABC) transporters and suppression of apoptosis. / Overexpression of P-glycoprotein (P-gp), one of the most important ABC transporters, can mediate the efflux of drugs out of cancer cells, leading to MDR and chemotherapy failure. The reversal of P-gp-mediated MDR by five tanshinones including tanshinone I, tanshinone IIA, cryptotanshinone, dihydrotanshinone and miltirone was evaluated in colon cancer cells. Bi-directional transport assay showed that only cryptotanshinone and dihydrotanshinone decreased the P-gp-mediated digoxin efflux in Caco-2 cells. The two tanshinones potentiated the cytotoxicities of doxorubicin and irinotecan in P-gp overexpressing colon cancer SW620 Ad300 cells. Moreover, these two tanshinones also increased intracellular accumulation of P-gp substrate in SW620 Ad300 cells, presumably by down-regulating P-gp mRNA and protein levels, as well as inhibiting P-gp ATPase activity. / Suppression of apoptosis can lead to MDR in cancer cells to anticancer agents with pro-apoptotic property. Hence, this study also investigated the circumvention of resistance to apoptosis in drug resistant colon cancer cells by cryptotanshinone and dihydrotanshinone, two potential MDR-reversing tanshinones. The drug resistant SW620 Ad300 cells were still sensitive to both cryptotanshinone and dihydrotanshinone in the promotion of cell death. When compared with the parental SW620 cells, the two tanshinones induced less apoptosis but more autophagy in the drug resistant cells. Further studies showed that cell viability was increased after inhibition of autophagy by siRNA interference or autophagy inhibitor. Thus, autophagy induced by the two tanshinones was pro-cell death in SW620 Ad300 cells, which could overcome resistance to apoptosis. / In addition, suppression of apoptosis can be caused by p53 defects/mutations, which were found in more than 50% of all human cancers. Our results also showed that apoptosis and autophagy induced by cryptotanshinone and dihydrotanshinone were independent of the status of p53 in colon cancer cells. The p53-independent cytotoxic actions of the two tanshinones could be useful in overcoming resistance to apoptosis in cancer cells caused by p53 defects/mutations. / Taken together, the current findings indicate a great potential of cryptotanshinone and dihydrotanshinone in the reversal of MDR caused by P-gp overexpression and suppression of apoptosis. They are promising candidates to be further developed as therapeutic agents in the adjuvant therapy for colon cancer, especially for the multidrug resistant cancer types. / 結腸癌是指形成在結腸組織的惡性腫瘤,在香港常見的癌症中排第一位,亦是香港排第二位的致死癌症。結腸癌的標準治療方案主要包括手術和化療。然而,多藥耐藥是結腸癌成功化療的一個障礙。事實上,大多數癌症引起的死亡都和在癌症的發展和化療的過程中產生的多藥耐藥有關。因此,多藥耐藥的逆轉對於結腸癌的成功化療非常重要。本研究旨在通過針對多藥耐藥兩種常見的機制ABC跨膜蛋白的過表達和抑制的細胞凋亡來探討丹參酮對結腸癌細胞多藥耐藥的逆轉。 / P-gp的過表達可介導藥物排出癌細胞,從而導致多藥耐藥和化療失敗。本研究評價了tanshinone I,tanshinone IIA,cryptotanshinone,dihydrotanshinone和miltirone對P-gp介導的結腸癌細胞多藥耐藥的逆轉。雙向轉運實驗表明,只有cryptotanshinone和dihydrotanshinone可以減少P-gp介導的digoxin外排。這兩個丹參酮可以增加doxorubicin和irinotecan在P-gp過表達的結腸癌SW620 Ad300細胞中的毒性。此外,這兩個丹參酮也增加P-gp底物在SW620 Ad300細胞內的積累,推測是通過下調P-gp的mRNA和蛋白水平,以及抑制P-gp的ATP酶活性。 / 抑制的細胞凋亡可導致腫瘤細胞對促凋亡的抗癌藥物产生多藥耐藥。因此,本研究也探討了cryptotanshinone和dihydrotanshinone能否克服結腸癌細胞的凋亡耐受。結果表明cryptotanshinone和dihydrotanshinone仍然能够杀死耐藥的SW620 Ad300細胞。當與SW620細胞相比,這兩個丹參酮在耐藥細胞中誘導的細胞凋亡較少,但自噬增多。進一步研究表明,這兩個丹參酮誘導的自噬是促進細胞死亡的,從而可以克服細胞的凋亡耐受。 / 此外,p53的缺陷/突變存在於50%以上的人類癌症中,并可以抑制細胞產生凋亡。結果表明,cryptotanshinone和dihydrotanshinone誘導的凋亡和自噬與p53在結腸癌細胞中的表達無關。這兩個丹參酮不依賴於p53的細胞毒性可以用於克服p53缺陷/突變引起的凋亡耐受。 / 綜上所述,本研究結果表明cryptotanshinone和dihydrotanshinone在逆轉P-gp的過表達和抑制的細胞凋亡引起的多藥耐藥中具有巨大潛力。它們可以進一步發展為有前途的治療劑并用於結腸癌的輔助治療,尤其是用於多藥耐藥的結腸癌。 / Hu, Tao. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 163-182). / Abstracts also in Chinese. / Title from PDF title page (viewed on 06, December, 2016). / Hu, Tao. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

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