Prevalence of Trichomonas vaginalis, Chlamydia trachomatis, Neisseria gonorrhoeae and human papillomavirus in a sexual health clinic setting in urban Sri Lanka.

The prevalences of Trichomonas vaginalis, Chlamydia trachomatis, Neisseria gonorrhoeae, and human papillomavirus (HPV) in Sri Lanka are not well reported; the objective of this study is to describe the prevalences of these four sexually transmitted infections among attendees of sexual health clinic in an urban setting. Vaginal swabs were collected from consenting women attending a sexual health clinic and tested for the presence of the above sexually transmitted infections using nucleic acid amplification techniques. Basic demographic details were sought from each participant (483 women of age range 14-61, median 30 years, IQR 12 years) via a research assistant-administered questionnaire. Overall, a prevalence of T. vaginalis, C. trachomatis, N. gonorrhoeae and HPV was 2.3%, (95% CI: 1.2-4.1%), 8.2% (95% CI: 5.6-11.4%), 7.6% (95% CI: 5.2-10.8%), and 44.4% (95% CI: 39.8-49.1%), respectively. Among the 197 positive for HPV, HPV6 accounted for 23.1%, HPV16 (12.5%), then HPV11, HPV66 and HPV58 were the commonest. Vaccine-related types (6/11/16/18) were detected in 59.9% of cases (95%CI: 52.7-66.8%). The high prevalence of sexually transmitted infections (45.2%) is a potential risk factor for an increase in HIV infections in the country and the high carriage of HPV supports the need for cervical cancer screening and prevention programmes.

Toxicity due to organophosphorus compounds: what about chronic exposure?

The inappropriate use of toxic chemicals is common in developing countries, where it leads to excessive exposure and high risks of unintentional poisoning. The risks are particularly high with the pesticides used in agriculture, where poor rural populations live and work in close proximity to these compounds, which are often stored in and around the home. It is estimated that 99% of all deaths from pesticide poisoning occur in developing countries. Whilst the acute toxicity of pesticides has been well documented, there is still relatively little known of the effects on health of chronic pesticide exposure. Organophosphate insecticides have been extensively used in agriculture in developing countries, with little protection for the communities and individuals thus exposed. Given the indisputable chronic exposure of vulnerable groups to organophosphate compounds, including pregnant women, the fetus and young children, the potential for widespread adverse effects is considerable. Thus, whilst there is some evidence that chronic exposure may have adverse effects on health, there is an urgent need for high-quality observational and interventional studies of both occupational and environmental exposure to these compounds.

Protection by garlic against adriamycin induced alterations in the oxido-reductive status of mouse red blood cells.

The effects of oral garlic supplementation on the activities of (a) the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPX) and (b) lipid peroxidation, as assessed by malondialdehyde (MDA) production in red blood cells of normal mice and those subject to oxidative stress by chronic administration of the anti-tumour drug adriamycin has been investigated. As expected, adria-mycin administration resulted in a significant increase in MDA generation (by 105.4%) and a decrease in GPX activity (by 23.8%) in the red blood cells. Although garlic had no significant effects on the basal levels of the antioxidant enzymes or MDA generation in red blood cells of normal mice (untreated with adriamycin), at doses of 20 mg/kg or 100 mg/kg, garlic was able to decrease significantly the adriamycin induced changes in the oxido-reductive status of the red blood cells. Thus, on administration of adriamycin to mice fed diets containing 20 mg/kg or 100 mg/kg garlic, the drug-induced increase in MDA generation was 38.2% and 22.5% respectively, less than that produced by adriamycin in mice fed normal diets, containing no garlic (105.4%). Similarly, in mice fed diets providing 20 mg/kg and 100 mg/kg garlic, adriamycin was able to decrease GPX activity by only 15.1% and 7.6% respectively, less than that produced by adriamycin in rats fed normal diets, containing no garlic (23.9%).

Involvement of superoxide dismutase and pyruvate:ferredoxin oxidoreductase in mechanisms of metronidazole resistance in Entamoeba histolytica.

Metronidazole resistance has been induced in an axenic strain of Entamoeba histolytica (HTH-56:MUTM) following continuous exposure to steadily increasing drug concentrations. The drug-resistant line is routinely maintained in normally lethal levels of metronidazole (10 microM). Resistance to this concentration of drug was developed over 177 days. Decreased pyruvate:ferredoxin oxidoreductase (PFOR) activity in anaerobic organisms is one mechanism of metronidazole resistance but in entamoeba, PFOR activity was not decreased in metronidazole-resistant parasites as determined by immunofluorescent assays and immunoblotting studies. 2-Oxoacid oxidoreductase activity, which appeared to be due to a single enzyme, PFOR, was evident with pyruvate as well as the alternative substrates, alpha-ketobutyrate, alpha-ketoglutarate and oxaloacetate. A marked increase in superoxide dismutase (SOD) activity was detected in metronidazole-resistant E. histolytica. Increased SOD activity has not previously been documented as a mechanism of drug resistance although SOD has been associated with a range of stress situations in other organisms.

The surface coat of bloodstream forms of Trypanosoma musculi from mice.

Iodination and immunoprecipitation techniques together with indirect fluorescent antibody tests identified two polypeptides (SP) of molecular weights 88,000-92,000 and 66,000-70,000 in the surface coat of bloodstream forms of the mouse trypanosome, Trypanosoma musculi. As parasites multiply and enter the early plateau phase of infection the 88,000-92,000 SP is present while the 66,000-70,000 SP is only detectable after the mid-plateau phase. Western blotting of parasite extracts showed that the 88,000-92,000 SP was present throughout the course of infection, but it appears to become masked by the 66,000-70,000 SP or possibly immunoglobulin from about 16 days after infection. Based on results when Western blots of parasite extracts were probed with antibodies affinity purified against the 88,000-92,000 SP, the two SP appear to be immunologically related and the smaller may be a cleavage product of the larger. This would explain why affinity purified antibodies to each SP bound to trypanosomes collected 8 days after infection, when only the 88,000-92,000 is detectable in parasite extracts. However, the failure of antibodies affinity purified against the 66,000-70,000 SP to bind to the 88,000-92,000 SP in Western blots suggests that the smaller SP has some epitopes that are immunologically distinct from those of the larger SP.