Amiodarone (AM) is a potent antidysrhythmic agent which can cause potentially life-threatening pulmonary fibrosis, and N-desethylamiodarone (DEA) is a metabolite of AM that may contribute to the toxicity of AM in vivo. Recent evidence has implicated the involvement of the renin-angiotensin system (RAS) in the initiation and progression of amiodarone-induced pulmonary toxicity. In cultured HPL1A human peripheral lung epithelial cells, we found AM to be converted to DEA minimally (< 2%) after 24 h of incubation, indicating that the HPL1A cell culture model can be used to study the effects of AM and DEA independently. Apoptotic cell death was assessed by annexin-V-FITC (ann-V) staining and by terminal deoxynucleotidyl transferase-mediated 2’-deoxyuridine 5’-triphosphate nick-end labeling (TUNEL), while necrotic cell death was determined by propidium iodide (PI) staining. The percentage of PI positive cells increased over six-fold after 24 h treatment with 20 μM AM (80.8%) compared to control (12.0%), and doubled after 24 h treatment with 3.5 μM DEA (20.4%) compared to control (10.8%). The percentage of ann-V positive cells decreased from 8.26% (control) to 1.56% following 24 h treatment with 10 μM AM and more than doubled after 24 h incubation with 3.5 μM DEA (22.0%) compared to control (9.86%) (p<0.05). Treatment for 24 h with 5.0 μM DEA caused the percentage of TUNEL positive cells to increase from 4.21% (control) to 26.7% (p<0.05). Vitamin E (5 – 20 μM) did not protect against AM or DEA cytotoxicity, as determined by ann-V and PI dual staining. Angiotensin II (100 pM – 1 μM) alone or in combination with AM or DEA did not alter cytotoxicity. Furthermore, the angiotensin converting enzyme inhibitor captopril did not protect against AM or DEA cytotoxicity. In conclusion, in vitro, AM activates primarily necrotic pathways, whereas DEA activates both necrotic and apoptotic pathways, and the RAS does not seem to be involved in AM or DEA cytotoxicity in HPL1A cells. Multiple mechanisms may contribute to the initiation of lung damage observed clinically, due to actions of both AM and its metabolite DEA. Keywords: amiodarone, desethylamiodarone, vitamin E, renin-angiotensin system / Thesis (Master, Pharmacology & Toxicology) -- Queen's University, 2009-11-26 13:57:09.65

Thesis (Ph. D.)--Washington State University, August 2008. / Includes bibliographical references.

Thesis (doctoral)--Rijksuniversiteit te Groningen.

No description available.

The prevailing paradigm is that cardiac ANG II is synthesized in the extracellular space from components of the circulating and/or local renin-angiotensin system. The recent discovery of intracrine effects of ANG II led us to determine whether ANG II is synthesized intracellularly in neonatal rat ventricular myocytes (NRVM). NRVM, incubated in serum-free medium, were exposed to isoproterenol or high glucose in the absence or presence of candesartan, which was used to prevent angiotensin type 1 (AT1) receptor-mediated internalization of ANG II. ANG II was measured in cell lysates and the culture medium, which represented intra- and extracellularly synthesized ANG II, respectively. Isoproterenol increased ANG II concentration in cell lysates and medium of NRVM in the absence or presence of candesartan. High glucose markedly increased ANG II synthesis only in cell lysates in the absence and presence of candesartan. Western analysis showed increased intracellular levels of angiotensinogen, renin, and chymase in high-glucose-exposed cells. Confocal immunofluorocytometry confirmed the presence of ANG II in the cytoplasm and nucleus of high-glucose-exposed NRVM and along the actin filaments in isoproterenol-exposed cells. ANG II synthesis was dependent on renin and chymase in high-glucose-exposed cells and on renin and angiotensin-converting enzyme in isoproterenol-exposed cells. In summary, the site of ANG II synthesis, intracellular localization, and the synthetic pathway in NRVM are stimulus dependent. Significantly, NRVM synthesized and retained ANG II intracellularly, which redistributed to the nucleus under high-glucose conditions, suggesting a role for an intracrine mechanism in diabetic conditions.

No description available.

Chan Wai-Pong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 114-135). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- General review of pancreas --- p.1 / Chapter 1.2 --- The renin-angiotensin system (RAS) --- p.4 / Chapter 1.3 --- Tissue RAS --- p.12 / Chapter 1.4 --- Hypoxia and RAS --- p.21 / Chapter 1.5 --- Pancreatitis and RAS --- p.25 / Chapter 1.6 --- Aim of study --- p.27 / Chapter Chapter 2 --- Method / Chapter 2.1 --- Experimental animals and rat models --- p.30 / Chapter 2.2 --- Immunohistochemistry --- p.33 / Chapter 2.3 --- Semi-quantitative reverse transcriptase-polymase chain reaction (RT-PCR) --- p.37 / Chapter 2.4 --- Western blot analysis --- p.41 / Chapter 2.5 --- "Standard curve, quantitative competitive RT-PCR (SC-QC-RT-PCR)" --- p.45 / Chapter 2.6 --- Data analysis --- p.48 / Chapter Chapter 3 --- Result / Chapter 3.1 --- Existence of a local RAS in the rat pancreas --- p.49 / Chapter 3.2 --- Effect of chronic hypoxia on RAS expression in neonatal rat --- p.59 / Chapter 3.3 --- Effect of chronic hypoxia on RAS expression in mature rat --- p.72 / Chapter 3.4 --- Effect of experimental pancreatitis on RAS expression --- p.86 / Chapter Chapter 4 --- Discussion / Chapter 4.1 --- Existence of a local RAS in the rat pancreas --- p.97 / Chapter 4.2 --- Regulation of pancreatic RAS by chronic hypoxia --- p.101 / Chapter 4.3 --- Regulation of pancreatic RAS by pancreatitis --- p.106 / Chapter 4.4 --- Conclusion --- p.111 / Chapter 4.5 --- Further work --- p.112 / Chapter Chapter 5 --- References --- p.114

Lau Tung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 142-157). / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.iii / Acknowledgements --- p.v / Table of Contents --- p.vi / List of Abreviations --- p.x / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Pancreas and its functions --- p.1 / Chapter 1.1.1 --- Structure of pancreas --- p.1 / Chapter 1.1.2 --- Exocrine function --- p.4 / Chapter 1.1.3 --- Endocrine function --- p.7 / Chapter 1.1.3.1 --- Pancreatic islet and islet cells --- p.7 / Chapter 1.1.3.2 --- Regulation of insulin secretion --- p.10 / Chapter 1.1.3.3 --- Mechanism for glucose-stimulated insulin release --- p.14 / Chapter 1.1.3.4 --- Bi-phase response of insulin secretion --- p.16 / Chapter 1.2 --- Pancreatic Renin-Angiotensin System --- p.19 / Chapter 1.2.1 --- Circulating RAS and local RAS --- p.19 / Chapter 1.2.2 --- RAS inhibitors --- p.25 / Chapter 1.2.2.1 --- Angiotensin converting enzyme inhibitor --- p.25 / Chapter 1.2.2.2 --- Non-specific Ang II receptor blocker --- p.28 / Chapter 1.2.2.3 --- Specific AT1 receptor antagonist --- p.29 / Chapter 1.2.2.4 --- Specific AT2 receptor antagonist --- p.30 / Chapter 1.2.3 --- RAS and Pancreas --- p.30 / Chapter 1.2.3.1 --- Expression and localization of pancreatic RAS --- p.30 / Chapter 1.2.3.2 --- Regulation of pancreatic RAS and its clinical relevance --- p.32 / Chapter 1.3 --- Islet Transplantation and RAS --- p.34 / Chapter 1.3.1 --- Whole pancreas and islet transplantation --- p.34 / Chapter 1.3.2 --- Problems encountered in islet transplantation --- p.36 / Chapter 1.3.3 --- Potential role of RAS in islet transplantation --- p.38 / Chapter 1.4 --- Diabetes Mellitus and RAS --- p.40 / Chapter 1.4.1 --- Diabetes Mellitus --- p.40 / Chapter 1.4.2 --- Type 1 diabetes and its animal model --- p.42 / Chapter 1.4.3 --- Type 2 diabetes and its animal model --- p.44 / Chapter 1.4.4 --- RAS blockade in diabetes patients --- p.46 / Chapter 1.4.5 --- Potential role of RAS in Diabetes Mellitus --- p.47 / Chapter 1.5 --- Aims of Study --- p.49 / Chapter Chapter 2 --- Materials and Methods / Chapter 2.1 --- Experimental animals and mouse models --- p.50 / Chapter 2.1.1 --- Experimental animals for islet isolation and transplantation --- p.50 / Chapter 2.1.2 --- Mouse model for type 2 diabetes --- p.51 / Chapter 2.2 --- Islet isolation and transplantation --- p.52 / Chapter 2.2.1 --- Enzymatic islet isolation --- p.52 / Chapter 2.2.2 --- Islet transplantation --- p.53 / Chapter 2.3 --- Biological assay on islet functions --- p.53 / Chapter 2.3.1 --- Measurement of islet insulin release --- p.53 / Chapter 2.3.2 --- Measurement of islet glucose oxidation rate --- p.56 / Chapter 2.3.3 --- Measurement of islet (pro)insulin biosynthesis --- p.59 / Chapter 2.3.4 --- Measurement of islet total protein synthesis --- p.60 / Chapter 2.4 --- Chronic losartan treatment --- p.62 / Chapter 2.5 --- Perfusion experiment of transplanted islet graft --- p.62 / Chapter 2.6 --- Insulin content of the islet graft --- p.63 / Chapter 2.7 --- Islet graft (pro)insulin and total protein biosynthesis --- p.64 / Chapter 2.8 --- Real-time RT-PCR Analysis --- p.64 / Chapter 2.8.1 --- Design of primers and probes --- p.67 / Chapter 2.8.2 --- Use of internal control --- p.69 / Chapter 2.8.3 --- RT-PCR reaction --- p.69 / Chapter 2.8.4 --- Calculation using the comparative CT method --- p.70 / Chapter 2.9 --- Western Blot Analysis --- p.71 / Chapter 2.10 --- Immunocytochemistry --- p.72 / Chapter 2.11 --- Statistical data analysis --- p.73 / Chapter Chapter 3 --- Results / Chapter 3 .1 --- Effect of Angiotensin II and Losartan on islet insulin release --- p.74 / Chapter 3.1.1 --- Insulin release from normal islets --- p.74 / Chapter 3.2 --- "Effect of Angiotensin II and Losartan on islet glucose oxidation rate, (pro)insulin and total protein biosynthesis" --- p.77 / Chapter 3.2.1 --- Glucose oxidation rate of isolated normal islets --- p.77 / Chapter 3.2.2 --- (pro)insulin and total protein biosynthesis of isolated normal islets --- p.77 / Chapter 3.3 --- Regulation of RAS components in islet transplantation --- p.81 / Chapter 3.3.1 --- Expression of RAS components in endogenous islets and transplanted islets --- p.81 / Chapter 3.3.2 --- Localization of AT1-receptor in endogenous islets --- p.87 / Chapter 3.3.3 --- Expression of AT1-receptor protein in endogenous and transplanted islets --- p.89 / Chapter 3.3.4 --- Relative abundance of RAS components in kidney and liver --- p.91 / Chapter 3.3.5 --- Insulin release from perfused transplanted islet graft --- p.93 / Chapter 3.3.5 --- (pro)insulin and total protein biosynthesis of transplanted islet graft --- p.96 / Chapter 3.4 --- Effect of Angiotensin II and losartan on diabetic islets --- p.99 / Chapter 3.4.1 --- Expression of RAS components in diabetic pancreas --- p.99 / Chapter 3.4.2 --- Localization of AT1 receptors in diabetic pancreas --- p.105 / Chapter 3.4.3 --- Insulin release from islets of type 2 diabetic mice --- p.107 / Chapter 3.4.4 --- (pro)insulin and total protein biosynthesis of islets from type 2 diabetic mice --- p.112 / Chapter Chapter 4 --- Discussion / Chapter 4.1 --- Effect of angiotensin II and losartan on islet insulin release --- p.116 / Chapter 4.2 --- Existence of local RAS in pancreatic islets --- p.119 / Chapter 4.3 --- Regulation of islet RAS components in transplanted islets --- p.122 / Chapter 4.4 --- Clinical relevance of islet RAS in transplantation --- p.125 / Chapter 4.5 --- Regulation of islet RAS by type 2 diabetes --- p.126 / Chapter 4.6 --- Clinical relevance of islet RAS in type 2 diabetes --- p.134 / Chapter 4.7 --- Conclusion --- p.140 / Chapter 4.8 --- Further studies --- p.141 / Chapter Chapter 5 --- Bibliography --- p.142

Thesis (M.Sc.)--University of Alberta, 2009. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science, Department of Physiology. Title from pdf file main screen (viewed on October 11, 2009). Includes bibliographical references.

published_or_final_version / Physiology / Doctoral / Doctor of Philosophy