Host genetic contribution to the cellular immune response to Chlamydia trachomatis: Heritability estimate from a Gambian twin study.

If the cellular immune response to Chlamydia trachomatis is subject to genetic influences, the degree and mechanisms of such genetic control may have important implications for vaccine development. We estimated the relative contribution of host genetics to the total variation in lymphoproliferative responses to C. trachomatis antigen by analyzing these responses in 64 Gambian twin pairs from trachoma endemic areas. Zygosity was determined by restriction fragment length polymorphism analysis of minisatellite probes and microsatellite typing. Proliferative responses to serovar A elementary body antigen were estimated in monozygotic (MZ) and dizygotic (DZ) twin pairs. We found a stronger correlation and lower within-pair variability in these responses in MZ than in DZ twin pairs. The heritability estimate was 0.39 (P = 0.07) suggesting that host genetic factors contributed 39% of the variation. A better understanding of these genetic influences will contribute to the elucidation of preventive therapies for ocular C. trachomatis infection and may identify important mechanisms in protection for rational vaccine construction.

Genetic regulation of fever in Plasmodium falciparum malaria in Gambian twin children.

The role of genetic factors in determining the clinical response of children to Plasmodium falciparum infection is not fully understood. A longitudinal survey of malaria morbidity in a cohort of 258 pairs of twin children was conducted in a rural area of Gambia to assess the extent to which genetic factors determine the host's susceptibility and clinical response to infection. The marginal correlation (which measures the excess probability of both twins being affected above that expected assuming independence) for malaria was higher in dizygous (DZ) than in monozygous (MZ) twin pairs, indicating that infection per se is largely determined by environmental factors. Once infected however, both members of an MZ pair were more likely to develop fever than were twins of a DZ pair, suggesting that genetic factors influence the presentation of clinical disease.

Comparative pharmacokinetic study between lenampicillin, bacampicillin and amoxycillin.

A cross-over study was performed comparing serum kinetics and urinary excretion in six healthy, fasting volunteers after ingestion of comparable amounts of lenampicillin, bacampicillin and amoxycillin. Venous blood samples and urine samples were taken at intervals for 6 and 12 h respectively post-tablet ingestion and assayed for free ampicillin or amoxycillin concentration with Bacillus subtilis as indicator organism. The most rapid Tmax and the highest Cmax were achieved with lenampicillin. The AUC was similar for lenampicillin, bacampicillin and amoxycillin as was the total percentage urinary recovery of antibiotic. Potential pharmacokinetic advantage of orally administered lenampicillin and bacampicillin compared to comparable doses of amoxycillin are higher peak serum concentrations (12.0 mg/l lenampicillin; 9.7 mg/l bacampicillin; 7.6 mg/l amoxycillin) and more rapid time to peak concentration (0.6 h lenampicillin; 0.7 h bacampicillin and 1.4 h amoxycillin).

The practice of traditional birth attendants in Zululand.

PIP: Approximately 60% of births in the Mseleni area of South Africa's Kwa Zulu province were home deliveries in 1984. Home deliveries in the area are generally attended by members of the pregnant woman's family. If difficulties are encountered during labor, the family will call upon a midwife, or Traditional Birth Attendant (TBA) for assistance. 14 TBAs from the Mseleni area were interviewed in 1984, about their technics and beliefs with regard to childbirth, and how they had acquired them. Most of the women reported that they had learned their technics from their mothers, who had also been TBAs. But TBAs from Mseleni District, where the local hospital was situated, had apparently learned from women working at the hospital that eggs and milk were valuable foods for their patients. The traditional beliefs and practices that the TBAs reported varied depending on the particular district they were from. Judged by the standards of modern medicine, some of these traditional practices appeared to be useful, while others seemed counterproductive. All of the interviewers expressed a willingness to participate in a training program at the hospital. It is recommended that such a program be conducted.^ieng