Chong Lung-wun. / Thesis (M.Sc.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 49-58). / Abstracts in English and Chinese. / Acknowledgement --- p.1 / Contents --- p.2 / Abstract --- p.4 / Chapter I. --- Introduction --- p.6 / Chapter 1. --- Nitrate therapy for angina patients --- p.7 / Chapter 1.1 --- The mode of action of nitrates --- p.8 / Chapter 1.2 --- Hypotheses for the nitrate tolerance --- p.9 / Chapter 1.2.1 --- The Sulfhydryl depletion hypothesis --- p.9 / Chapter 1.2.2 --- Neurohormonal hypothesis --- p.10 / Chapter 1.2.3 --- Plasma volumc expansion hypothesis --- p.10 / Chapter 1.2.4 --- Free-radical hypothesis --- p.11 / Chapter 2. --- Testosterone therapy for angina patients --- p.12 / Chapter 3. --- Nitric Oxide and Steroidogenesis --- p.13 / Chapter II. --- Materials and Methods --- p.14 / Chapter 1. --- Subjects --- p.14 / Chapter 2. --- Method for measuring nitrite and nitrate in plasma --- p.16 / Chapter 3. --- Method for the determination of total and free testosterone in blood --- p.24 / Chapter 3.1 --- Reagent preparation --- p.24 / Chapter 3.2 --- Assay procedure for total testosterone --- p.28 / Chapter 3.3 --- Assay procedure for free testosterone --- p.29 / Chapter 3.4 --- Determination of working antiserum for free testosterone assay --- p.30 / Chapter 4. --- Method for the determination of serum Cortisol --- p.31 / Chapter III. --- Result --- p.33 / Chapter 1. --- Summary of nitric oxide assay performance --- p.33 / Chapter 2. --- Summary of total testosterone assay performance --- p.34 / Chapter 3. --- Summary of free testosterone assay performance --- p.34 / Chapter 4. --- Data analysis --- p.35 / Chapter IV. --- Discussion --- p.43 / Chapter V. --- Conclusion --- p.47 / Chapter VI. --- References --- p.49

Orientadores: Carlos Arturo Levi D'Ancona, Edson Antunes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-25T22:31:02Z (GMT). No. of bitstreams: 1 Miyaoka_Ricardo_D.pdf: 38810158 bytes, checksum: a73083863b9c18c44630b11b53472286 (MD5) Previous issue date: 2014 / Resumo: Introdução: A terapia medicamentosa expulsiva no tratamento da calculose ureteral visa abreviar o tempo para eliminação espontânea do cálculo e evitar a necessidade de uma intervenção cirúrgica. As terapêuticas atuais baseiam-se essencialmente em bloqueadores de canais de cálcio e bloqueadores alfa-adrenérgicos, mas têm eficácia questionável, conforme demonstram estudos clínicos mais recentes e com alto nível de evidência. Assim, faz-se necessária a investigação persistente de novos agentes para este fim. Objetivos: Descrever modelo padronizado de contratilidade ureteral in vitro com segmentos isolados de ureter humano a fim de avaliar o relaxamento provocado pelo estimulador da guanilato ciclase solúvel BAY 41-2272; avaliar o envolvimento da via do NO-GMPc-PDE5 e dos canais de potássio e urotélio neste processo; avaliar a expressão das enzimas guanilato ciclase solúvel (GCs), óxido nítrico sintase (NOS) e fosfodiesterase tipo 5 (PDE5) no ureter por meio de imunohistoquímica. Materiais e Métodos: Segmentos de ureter distal de 17 doadores falecidos de múltiplos órgãos de ambos sexos (24 ¿ 65 anos de idade, média 40 ± 3.2 anos; homens 2:1 mulheres) foram utilizados. A contratilidade ureteral foi avaliada em banho de solução de Krebs e o tecido pré-contraído com KCl 80nM . Os valores de potência foram determinados como o log negativo da concentração molar para induzir 50% do relaxamento máximo nos espécimes pré-contraídos com KCl. O teste não-pareado T de Student foi usado para as comparações. Resultados: O BAY 41-2272 produziu relaxamento em ureter isolado em tecidos pré-contraídos com KCl (80 mM) com valores de potência (pEC50) e relaxamento máximo (Emax) de 5,82 ± 0,12 (n=8) e 84 ± 5%, respectivamente. A adição do inibidor da sintase de óxido nítrico (L-NAME, 100 ?M, n=6) ou da guanilato ciclase solúvel (ODQ, 10 ?M, n=6) reduziu em, 21 e 44% (P<0,05) a Emax, respectivamente, sem alteração dos valores de pEC50. A pré-incubação do inibidor da PDE5, sildenafil (100 nM) potencializou (pEC50: 6,39 ± 0,10, n=8, P<0,05) o relaxamento induzido pelo BAY 41-2272 em comparação à curva controle. A adição dos bloqueadores inespecíficos de canais de potássio (glibenclamida) ou ATP-dependentes (tetraetilamônio ¿ TEA) e a ausência de urotélio não interferiram nos parâmetro farmacológicos do BAY 41-2272. A imunorreatividade mostrou a presença da eNOS no endotélio de estruturas vasculares do ureter e nNOS no urotélio, estruturas nervosas e, fracamente, na musculatura lisa. A GCs é expressa tanto no urotélio como na musculatura lisa. A PDE5 é expressa, exclusivamente, na musculatura lisa. Conclusão: O BAY 41-2272 provoca relaxamento em segmentos ureterais humanos pré-contraídos com KCl em modelo in vitro de forma concentração-dependente, essencialmente pela ativação da guanilato ciclase presente no músculo liso, e não no urotélio, apesar de um mecanismo GMPc-independente poder estar envolvido. Esta nova classe farmacológica pode ter papel no tratamento clínico de cálculos ureterais obstrutivos / Abstract: Introduction: Medical expulsive therapy in the treatment of ureteral calculi aims to reduce the timeframe for spontaneous stone expulsion avoiding an unwanted surgical intervention. Current clinical therapy is essentially based upon the use of calcium channel blockers and alpha-adrenergic antagonists which have been recently shown to offer questionable efficacy according to well-designed recent clinical trials with a high level of evidence. As such, it is necessary to continue the pursuit for new agents that could abbreviate the time for ureteral stone expulsion. Objectives: To report on a standardized ureteral contractility in vitro model with isolated human ureter segments in order to characterize the relaxation induced by soluble guanylate cyclase stimulator BAY 41-2272; to assess the involvement of NO-cGMP-PDE5 pathway and potassium channels in ureteral relaxation; to assess the immunohystochemical expression of endothelial (eNOS) and neuronal NO synthase (nNOS), soluble guanylate cyclase (sGC) and type 5 phosphodiesterase (IPDE5) in human ureter. Materials and Methods: Distal ureteral segments harvested from 17 multiple organs deceased donors (age 24-65; mean 40 ± 3.2; men/women ratio 2:1) were used. Ureteral contractility was assessed with segments immersed into Kreb¿s solution after being pre contracted with 80mM KCl. BAY 41-2272 induced ureteral relaxation in KCl pre contracted isolated segments with pEC50 and Emax of 5,82 ± 0,12 (n=8) and 84 ± 5%, respectively. Addition of a NOS inhibitor (L-NAME, 100 ?M, n=6) or soluble guanylate cyclase (ODQ, 10 ?M, n=6) led to a reduction of 21% and 44% in Emax values (P<0,05), respectively. pEC50 values remained unaltered. PDE5 inhibitor sildenafil (100 n M) enhanced (pEC50: 6,39 ± 0,10, n=8, P<0,05) the relaxing effect provoked by BAY 41-2272 compared with control curve. Neither unspecific potassium channel blockers glibenclamide nor ATP-dependent potassium channel blocker tetraethylammonium (TEA) nor ureteral urothelium removal influenced the relaxation response by BAY 41-2272. Immunochemistry markers showed eNOS expression in ureteral vascular endothelium, nNOS in urothelium, nerve structures and with less intensity in smooth muscle. Soluble guanylate cyclase was present in urothelium and smooth muscle; and PDE5 was only expressed in ureteral smooth muscle. Conclusions: BAY 41-2272 relaxes human isolated ureter segments in a concentration-dependent manner, mainly by activating the sGC enzyme in smooth muscle cells rather than in the urothelium, although a cyclic guanosine monophosphate-independent mechanism may exist. This pharmacological class may have a role in treating ureteral obstructive calculi / Doutorado / Fisiopatologia Cirúrgica / Doutor em Ciências da Cirurgia

In the studies about ovarian cancer cells, basal iNOS expression in the chemosensitive OV2008 cells was significantly higher than in the chemoresistant C13* cells. Cisplatin further increased iNOS expression in OV2008 cells, but had no effect in C13* cells. Furthermore, cisplatin dramatically reduced the expression levels of eNOS and nNOS, but again only in OV2008 cells. The data suggest that failure of cisplatin to upregulate iNOS and downregulate eNOS and nNOS in C13* cells could be an etiological factor in chemoresistance. Addition of exogenous NO at high levels, using SNAP, significantly increased p53 protein levels and caused apoptosis in both cell types. Specific iNOS inhibitor (1400W) partially blocked the pro-apoptotic effects of cisplatin in OV2008 cells, suggesting involvement of iNOS in cisplatin-induced apoptosis. However, blocking of all three isoforms of NOS with NG-amino-L-arginine in C13* cells dramatically changed these cells from chemoresistant to chemosensitive, greatly potentiating the pro-apoptotic effects of cisplatin. / Inhibition of Src-kinase activity reduces DNA synthesis in ovarian cancer cells. In an in vitro experiment, Src phosphorylated PKG on a tyrosine residue and PKG, presumable via serine-phosphorylation of Src, enhanced Src auto(tyrosine)phosphorylation. In ovarian cancer cells, inhibition of basal PKG activity with DT-2 decreased both basal and EGF-stimulated Src kinase activation and DNA synthesis. The data suggest that PKG at basal activity, is necessary for both basal and growth factor-stimulated Src kinase activation and enhanced DNA synthesis in human ovarian cancer cells. / The novel role of sGC/cGMP/PKG pathway on stimulating cell proliferation, potentially via interaction with the Src kinase pathway in human ovarian cancer cells, was demonstrated. ODQ dramatically reduced DNA synthesis rates, suggesting that basal sGC activity and basal cGMP levels are needed for ovarian cancer cell proliferation. DT-2 also reduced cell proliferation, suggesting the direct involvement of PKG. ANP and BNP had no effect on cell proliferation, suggesting that further activation of cGMP/PKG pathway above basal levels does not further enhance cell proliferation. / The present study also demonstrated that elevating cGMP slightly above the basal levels further protects pancreatic islet cells against spontaneous onset of apoptosis. The results showed that natriuretic peptides (both ANP and BNP) and low-level NO (i.e. physiological levels) as supply by NO donor, S-nitroso-N-acetylpenicilamine (SNAP) further prevented spontaneous apoptosis in pancreatic islets after isolation, whereas NO at high concentrations (i.e. pathological levels) promoted apoptosis in pancreatic islet cells. The commonly-used PKG inhibitor KT5823 and the newly-developed specific PKG inhibitor DT-2 completely prevented anti-apoptosic effect of ANP, suggesting the direct involvement of PKG in protection against spontaneous apoptosis. / The present study demonstrated that basal activity of sGC/cGMP/PKG signaling pathway is essential for partially limiting spontaneous apoptosis in pancreatic islet cells. The sGC inhibitor ODQ caused induction of apoptosis, which was completely blocked by co-treatment with ANP or BNP, agents that elevate cGMP via pGC, bypassing the ODQ block. Co-treatment with 8-Br-cGMP, a direct activator of PKG also completely prevented ODQ-induced apoptosis in islets. / Leung Lai-han. / "July 2006." / Adviser: Ronald Ray Fiscus. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1483. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 175-191). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.