Zhao Hailu. / "June 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 192-210). / 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 Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

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.

BACKGROUND AND OBJECTIVES: Type 2 diabetes mellitus (T2DM) is a complex disease with genetic predisposition and histopathological characterization. Pancreatic islet amyloidosis, hyaline arteriolosclerosis, and diabetic glomerulopathy are histopathological hallmarks of T2DM at autopsy examination. The associations of genetic variants with diabetic amyloidosis, arteriosclerosis and glomerulopathy have not been fully elucidated. Several candidate genes including apolipoprotein E (ApoE), insulin degrading-enzyme (IDE) and glucose transporter-1 ( GLUT1) have been reported to increase risk of T2DM in human studies although results are not always consistent. Capitalizing on the pathological hallmarks of T2DM, I used autopsy specimens to investigate the risk associations of polymorphisms of ApoE (rs429358 and rs7412), IDE (rs6583813) and GLUT1 (rs710218) genes with clinical features and specific pathological changes in diabetic kidney and pancreas. I further explored the mechanisms of these associations by evaluating the histopathological changes and protein expression in pancreas and kidney. / CONCLUSIONS: These findings suggest that genetic factors have important effects in the development of tissue-specific changes and chronic complications in T2DM. Islet amyloidosis, arteriosclerosis and glomerulosclerosis in T2DM may share common pathogenetic processes as suggested by the coexistence of chaperone proteins, amyloid P and ApoE. Genetic--pathologic correlation studies are useful in advancing our understanding of the mechanisms of complex diseases such as T2DM. / METHODS AND MATERIALS: Genomic DNA was extracted from white blood cell-concentrated paraffin embedded formalin fixed spleen tissues. Genotyping for ApoE, IDE and GLUT1 polymorphisms was determined by polymerase chain reaction (PCR) and ligase detection reaction (LDR). The pathological changes were blindly assessed in pancreatic and kidney tissues of autopsy specimens. Protein expression of these genes was examined by immunostaining and quantified by using Metamorph image analysis system. / RESULTS: In a consecutive study population of 3693 autopsy specimens containing 328 T2DM and 209 control cases, the respective frequencies of genotypes were as follows: 1) TT of GLUT1 rs710218: 11.2% vs. 11.3%; 2) ApoE epsilon2: 19.4% vs. 10.9%; 3) ApoE epsilon4: 12.1% vs. 9.1% and 4) C carriers of IDE rs6583813: 51.2% vs. 47.9%. The key genotype-phenotype correlations were as follows. 1) In the T2DM cases, GLUT1 rs710218 IT genotype carriers (0% in TT genotype vs. 59.1% in AA genotype, P=0.0407) were less likely but ApoE epsilon 2 allele carriers (57.1% in epsilon2 allele carriers vs. 23.5% in epsilon3 allele carriers P=0.0382) were more likely to have diabetic glomerular hypertrophy than referential group. ApoE epsilon2 carriers showed increased glomerular ApoE protein expression with the immunoreactivity found mainly in the mesangial regions and nodular lesions. On the other hand, ApoE epsilon 3/epsilon4 cases had diffuse ApoE expression in glomerular capillaries. 2) ApoE epsilon4 carriers were more likely to have islet amyloidosis than non-carriers (62.5% in epsilon4 allele carriers vs. 23.6% in epsilon 3 allele carriers P=0.0232). There was immunolocalization of the chaperone proteins, amyloid P and ApoE in both islet amyloid deposits and arterial walls with hyaline arteriolosclerosis. 3) In T2DM cases, IDE rs6583813 C allele carriers had higher prevalence of vascular disorders [hypertension (67.4% vs. 43.6%, P=0.0332), death due to cardiovascular disease (58.1% vs. 25.6%, P=0.0479) and cerebral vascular accident (CVA) (20.9% vs. 2.4%, P=0.0412)1 than T allele carriers. / Guan, Jing. / Adviser: Chan Chung Ngor Juliana. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 175-192). / 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, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.