Intravaginal cleansing among women attending a sexually transmitted infection clinic in Kingston, Jamaica.

OBJECTIVES: Although common worldwide, intravaginal cleansing is associated with poor health outcomes. We sought to describe intravaginal cleansing among women attending a sexually transmitted infection (STI) clinic in Jamaica. METHODS: We examined intravaginal cleansing ("washing up inside the vagina", douching, and products or materials used) among 293 participants in a randomized trial of counselling messages at an STI clinic in Kingston. We focussed on information on intravaginal cleansing performed in the 30 days and three days preceding their baseline study visit. We describe reported cleansing behaviours and used logistic regression to identify correlates of intravaginal cleansing. RESULTS: Fifty-eight per cent of participants reported intravaginal cleansing in the previous 30 days, and 46% did so in the three days before baseline. Among those who cleansed in the previous 30 days, 88% reported doing so for hygiene unrelated to sex, and three-fourths reported generally doing so more than once per day. Soap (usually with water) and water alone were the most common products used for washing; commercial douches or detergents were reported infrequently. Intravaginal cleansing in the three days before the baseline visit was positively associated with having more than one sex partner in the previous three months (adjusted odds ratio [AOR], 1.9; 95% CI, 1.1, 3.2), and negatively associated with experiencing itching in the genital area at baseline (AOR, 0.6; 95% CI, 0.4, 1.0). CONCLUSIONS: A large proportion of women attending STI clinics in Jamaica engage in frequent intravaginal cleansing, indicating a need for clinicians to discuss this topic with them accordingly.

Stability and effectiveness of chlorine disinfectants in water distribution systems.

A test system for water distribution was used to evaluate the stability and effectiveness of three residual disinfectants--free chlorine, combined chlorine, and chlorine dioxide--when challenged with a sewage contaminant. The test distribution system consisted of the street main and internal plumbing for two barracks at Fort George G. Meade, MD. To the existing pipe network, 152 m (500 ft) of 13-mm (0.5 in.) copper pipe were added for sampling, and 60 m (200 ft) of 2.54-cm (1.0 in.) plastic pipe were added for circulation. The levels of residual disinfectants tested were 0.2 mg/L and 1.0 mg/L as available chlorine. In the absence of a disinfectant residual, microorganisms in the sewage contaminant were consistently recovered at high levels. The presence of any disinfectant residual reduced the microorganism level and frequency of occurrence at the consumer's tap. Free chlorine was the most effective residual disinfectant and may serve as a marker or flag in the distribution network. Free chlorine and chlorine dioxide were the least stable in the pipe network. The loss of disinfectant in the pipe network followed first-order kinetics. The half-life determined in static tests for free chlorine, chlorine dioxide, and combined chlorine was 140, 93, and 1680 min.

Histidyl-transfer ribonucleic acid synthetase in positive control of the histidine operon in Salmonella typhimurium.

Histidyl-transfer ribonucleic acid (tRNA) synthetase (HRS), coded by the hisS gene, appears to play two roles in regulation of the histidine operon of Salmonella typhimurium: (i) in synthesis of a critical effector molecule, histidyl-tRNA, and (ii) a more direct effect elicited by the presence of the enzyme protein itself. The specific activity of HRS was elevated either by mutations in the strB locus or in hisS(+) merodiploids of Escherichia coli/S. typhimurium and S. abony/S. typhimurium. In each case, an increase in HRS was accompanied by an increase in histidine operon expression, indicating that HRS may be involved in positive control of the histidine operon. It is unlikely that HRS leads to increased histidine operon expression merely by acting as a "sponge" for charged tRNA. Rather, HRS appears to influence operon expression by interaction with some effector molecule other than charged tRNA or by a direct interaction with the histidine operator-promoter region. The functional level of histidine operon expression has no effect on HRS specific activity.