Significance Factors that influence the virulence of HIV are of direct relevance to ongoing efforts to contain, and ultimately eradicate, the HIV epidemic. We here investigate in Botswana and South Africa, countries severely affected by HIV, the impact on HIV virulence of adaptation of HIV to protective HLA alleles such as HLA-B*57. In Botswana, where the epidemic started earlier and reached higher adult seroprevalence than in South Africa, HIV replication capacity is lower. HIV is also better adapted to HLA-B*57, which in Botswana has no protective effect, in contrast to its impact in South Africa. Modelling studies indicate that increasing antiretroviral therapy access may also contribute to accelerated declines in HIV virulence over the coming decades.

Introduction Aboriginal and Torres Strait Islander Australians living in remote locations suffer disproportionately from chronic hepatitis B (CHB). Defining the temporospatial epidemiology of the disease-and assessing the ability of local clinicians to deliver optimal care-is crucial to improving patient outcomes in these settings. Methods The demographic, laboratory and radiology findings in all patients diagnosed with CHB after 1990, and presently residing in remote Far North Queensland (FNQ), tropical Australia, were correlated with their management and clinical course. Results Of the 602 patients, 514 (85%) identified as Aboriginal and Torres Strait Islander Australians, 417 (69%) of whom had Torres Strait Islander heritage. Among the 514 Aboriginal and Torres Strait Islander Australians, there were only 61 (12%) born after universal postnatal vaccination was introduced in 1985. Community CHB prevalence varied significantly across the region from 7/1707 (0.4%) in western Cape York to 55/806 (6.8%) in the Eastern Torres Strait Islands. Although 240/602 (40%) are engaged in care, with 65 (27%) meeting criteria for antiviral therapy, only 43 (66%) were receiving this treatment. Among 537 with complete data, 32 (6%) were cirrhotic, of whom 15 (47%) were engaged in care and 10 (33%) were receiving antiviral therapy. Only 64/251 (26%) in whom national guidelines would recommend hepatocellular carcinoma (HCC) surveillance are receiving screening, however, only 20 patients have been diagnosed with HCC since 1999. Conclusion Vaccination has had a dramatic effect on CHB prevalence in FNQ in only a generation. However, although engagement in care is the highest in Australia, this is not translating into

The effects of the Pseudomonas aeruginosa virulence factor pyocyanin (PCN) on the contractile function of porcine coronary arteries was investigated in vitro. Artery rings (5 mm) were suspended in organ baths containing Krebs' solution for the measurement of isometric tension. The effect of PCN on resting and precontracted coronary arteries was initially investigated with various agents. Arteries were precontracted with prostaglandin (PG) F2α or potassium chloride and endothelium-dependent relaxations were induced by various agents in the presence of PCN. Pyocyanin (0.1-10 μmol/L) evoked small-amplitude, dose-dependent contractions in resting porcine coronary arteries. In addition, PCN amplified the contractile response to PGF2α , but did not alter responses to carbachol. Pyocyanin (0.1-10 μmol/L) significantly inhibited endothelium-dependent relaxations evoked by neurokinin A. Pyocyanin also inhibited relaxations evoked by diethylamine nitric oxide (a nitric oxide donor), forskolin (an adenylate cyclase activator), dibuytyryl-cAMP (a cAMP analogue), 8-bromo-cGMP (a cGMP analogue) and P1075 (a KATP channel activator), but not isoprenaline (β-adrenoceceptor agonist). These results indicate that physiological concentrations of PCN interfere with multiple intracellular processes involved in vascular smooth muscle relaxation, in particular pathways downstream of nitric oxide release. Thus, PCN may alter normal vascular function in patients infected with P. aeruginosa.

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