Publications

BACKGROUND

The use of genotyping to distinguish recrudescent from new infections is currently recommended for all clinical antimalarial efficacy trials by the World Health Organization. However, genotyping-adjusted drug efficacy estimates may vary between trials due to the use of different genotyping methods and to the different settings in which these methods are applied.

METHODS

A systematic review of all clinical antimalarial efficacy trials published from 1995-2005 was performed to characterize the use of genotyping, including the methods used and the effect of these methods on estimates of drug efficacy.

RESULTS

In a multivariate analysis, the method of interpretation of genotyping results, the studied therapy, the location of the trial, and the duration of study follow-up all had statistically significant effects on the percent of genotyped outcomes classified as new infections.

CONCLUSION

Criteria for defining appropriate, standardized genotyping methods for use in different settings are needed to enable more accurate estimates of antimalarial drug efficacy and better comparison between trials. The advantages and disadvantages of different genotyping methods and their potential impact in various settings are discussed.

This study aimed to systematically review and describe the evidence on chlamydia and gonorrhoea reinfection among men, and to evaluate the need for retesting recommendations in men. PubMed and STI conference abstract books from January 1995 to October 2006 were searched to identify studies on chlamydia and gonorrhoea reinfection among men using chlamydia and gonorrhoea nucleic acid amplification tests or gonorrhoea culture. Studies were categorised as using either active or passive follow-up methods. The proportions of chlamydial and gonococcal reinfection among men were calculated for each study and summary medians were reported. Repeat chlamydia infection among men had a median reinfection probability of 11.3%. Repeat gonorrhoea infection among men had a median reinfection probability of 7.0%. Studies with active follow-up had moderate rates of chlamydia and gonorrhoea reinfection among men, with respective medians of 10.9% and 7.0%. Studies with passive follow-up had higher proportions of both chlamydia and gonorrhoea reinfections among men, with respective medians of 17.4% and 8.5%. Proportions of chlamydia and gonorrhoea reinfection among men were comparable with those among women. Reinfection among men was strongly associated with previous history of sexually transmitted diseases and younger age, and inconsistently associated with risky sexual behaviour. Substantial repeat chlamydia and gonorrhoea infection rates were found in men comparable with those in women. Retesting recommendations in men are appropriate, given the high rate of reinfection. To optimise retesting guidelines, further research to determine effective retesting methods and establish factors associated with reinfection among men is suggested.

Quantitative real-time PCR (qPCR) is a commonly used validation tool for confirming gene expression results obtained from microarray analysis; however, microarray and qPCR data often result in disagreement. The current study assesses factors contributing to the correlation between these methods in five separate experiments employing two-color 60-mer oligonucleotide microarrays and qPCR using SYBR green. Overall, significant correlation was observed between microarray and qPCR results (rho=0.708, p<0.0001, n=277) using these platforms. The contribution of factors including up- vs. down-regulation, spot intensity, rho-value, fold-change, cycle threshold (C(t)), array averaging, tissue type, and tissue preparation was assessed. Filtering of microarray data for measures of quality (fold-change and rho-value) proves to be the most critical factor, with significant correlations of rho>0.80 consistently observed when quality scores are applied.

Mycoplasmas cause chronic inflammation and are implicated in asthma. Mast cells defend against mycoplasma infection and worsen allergic inflammation, which is mediated partly by histamine. To address the hypothesis that mycoplasma provokes histamine release, we exposed mice to Mycoplasma pulmonis, comparing responses in wild-type and mast cell-deficient KitW-sh/KitW-sh (W-sh) mice. Low histamine levels in uninfected W-sh mice confirmed the conventional wisdom that mast cells are principal sources of airway and serum histamine. Although mycoplasma did not release histamine acutely in wild-type airways, levels rose up to 50-fold above baseline 1 week after infection in mice heavily burdened with neutrophils. Surprisingly, histamine levels also rose profoundly in infected W-sh lungs, increasing in parallel with neutrophils and declining with neutrophil depletion. Furthermore, neutrophils from infected airway were highly enriched in histamine compared with naive neutrophils. In vitro, mycoplasma directly stimulated histamine production by naive neutrophils and strongly upregulated mRNA encoding histidine decarboxylase, the rate-limiting enzyme in histamine synthesis. In vivo, treatment with antihistamines pyrilamine or cimetidine decreased lung weight and severity of pneumonia and tracheobronchitis in infected W-sh mice. These findings suggest that neutrophils, provoked by mycoplasma, greatly expand their capacity to synthesize histamine, thereby contributing to lung and airway inflammation.