A current hypothesis states that tolerance to nitroglycerin (GTN) involves increased formation of superoxide (O 2 . ). Studies showing that inhibitors of protein kinase C (PKC) prevent tolerance to GTN suggest the involvement of PKC activation, which can also increase O 2 . . We examined the roles of O 2 . , peroxynitrite (ONOO Ϫ ), and PKC activation in GTN tolerance. Pre-exposure of rat aortic rings to GTN (5 ϫ 10 Ϫ4 M) for 2 h caused tolerance to the vasodilating effect of GTN, as evidenced by a substantial rightward shift of GTN concentration-relaxation curves. This shift was reduced by treatment of the rings with the antioxidants uric acid, vitamin C, or tempol or the PKC inhibitor chelerythrine. We also found that O 2 . generation via xanthine/ xanthine oxidase in the bath induced tolerance to GTN. However, responses to nitroprusside were not affected. In vivo tolerance produced in rats by 3-day i.v. infusion of GTN was also almost completely prevented by coinfusion of tempol. In bovine aortic endothelial cells (EC), addition of GTN produced a marked increase in tyrosine nitrosylation, indicating increased ONOO Ϫ formation. This action was blocked by prior treatment with uric acid, superoxide dismutase, N G -nitro-L-arginine methyl ester, or chelerythrine. We also demonstrated that GTN translocates the ␣-and ⑀PKC isoforms in EC. However, PKC was not affected by GTN treatment. In conclusion, tolerance to GTN involves enhanced production of O 2 . and ONOO Ϫ and activation of NO synthase. Furthermore, sustained activation of ␣-and ⑀PKC isozymes in EC by GTN may play a role in development of tolerance.

Injecting drug use plays a critical role in the transmission of HIV in Vietnam. This paper provides a comprehensive review of studies on risks of HIV infection among injecting drug users (IDUs) in Vietnam. Current research evidence shows that the age at which drug initiation starts is becoming younger and the transition time between non-injecting to injecting drug use becoming shorter. The practice of needle sharing and unprotected sex was quite common among the IDUs. Although most of the IDUs generally had good knowledge of HIV transmission routes, most IDUs were not aware of their infection status. Data from a national surveillance programme shows that a third of the IDUs were HIV positive. Amongst all HIV positive cases, almost two-thirds had a history of intravenous drug use. A number of studies have identified a range of risk factors and barriers to minimize the risk of HIV infection in IDUs. This paper discusses these issues and makes recommendations for changes to HIV/AIDS policies, programme interventions as well as future research on the topic.

Sexually transmitted infections (STIs) in Vietnam have been increasing. Control of STIs among female sex workers (FSWs) is important in controlling the epidemic. Effective STI control requires that physicians are skilful in taking sexual history for FSW patients. Three hundred and seventy-one physicians responded to a survey conducted in three provinces in Vietnam. The respondents were asked whether they asked FSW patients about their sexual history and information asked during sexual history taking. The respondents were also asked about their barriers for taking sexual history. Over one-fourth (27%) respondents always, over half (54%) respondents sometimes and 19% respondents never obtained a sexual history from FSW patients. Multivariable analysis revealed that factors associated with always taking a sexual history were being doctor, training in STIs and working at provincial level facilities. Physician's discomfort was found to be inversely associated with training on communication with patients, seeing 15 or fewer patients a week, working at provincial level facilities. Issues in sexual history taking among FSW patients in general practice in Vietnam were identified. These issues can help STI control for FSW patients and need due attention in order to improve STI management in Vietnam.

BackgroundSexually transmitted infections (STIs) are a public health problem in Vietnam with sub-optimal care in medical practice. Identifying practitioners’ perceived barriers to STI care is important to improve care for patients with STIs.MethodsA cross-sectional survey was conducted among 451 physicians. These physicians were dermatology and venereology (D&V) doctors, obstetrical/gynaecological (Ob/Gyn) doctors, general practitioners, and assistant doctors working in health facilities at provincial, district and communal levels in three provinces in Vietnam.ResultsAlmost all (99%) respondents mentioned at least one barrier to STI care. The barriers were “lack of STI training” (57%), “lack of professional resources” (41%), “lack of time” (38%), “lack of reimbursement” (21%), “lack of privacy/confidentiality” (17%), “lack of counselling” (15%), and “not the role of primary care provider” (7%). Multivariable logistic regression analysis showed that “lack of professional resources” was associated with respondents being in medical practice for ten years or under (vs. 11–20 years), and working at district or communal health facilities (vs. provincial facilities); “lack of time” were associated with respondents being female, seeing more than 30 patients a week (vs. <15 patients/week); and “lack of privacy/confidentiality” was associated with physicians’ seeing more than 30 patients a week (vs. <15 patients/week).ConclusionThe study has identified several barriers to STI care in medical practice in Vietnam. Results of the study can be used to improve areas in STI care including policy and practice implications.

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