Background

Follow up of Human Immunodeficiency Virus (HIV)-exposed infants is an important component of Prevention of Mother-to-Child Transmission (PMTCT) programmes in order to ascertain infant outcomes post delivery. We determined HIV transmission, mortality and loss to follow-up (LTFU) of HIV-exposed infants attending a postnatal clinic in an urban hospital in Durban, South Africa.

Methods

We conducted a retrospective cohort study of infants born to women in the PMTCT programme at McCord Hospital, where mothers paid a fee for service. Data were abstracted from patient records for live-born infants delivered between 1 May 2008 and 31 May 2009. The infants’ LTFU status and age was based on the date of the last visit. HIV transmission was calculated as a proportion of infants followed and tested at six weeks. Mortality rates were analyzed using Kaplan-Meier (K-M), with censoring on 15 January 2010, LTFU or death.

Results

Of 260 infants, 155 (59.6%) remained in care at McCord beyond 28 weeks: one died at < 28 days, three died between one to six months; 34 were LTFU within seven days, 60 were LTFU by six months. K-M mortality rate: 1.7% at six months (95% confidence interval (CI): 0.6% to 4.3%). Of 220 (83%) infants tested for HIV at six weeks, six (2.7%, 95% CI: 1.1% to 5.8%) were HIV-infected. In Cox regression analysis, late antenatal attendance (≥ 28 weeks gestation) relative to attending in the first trimester was a predictor for infant LTFU (adjusted hazards ratio = 2.3; 95% CI: 1.0 to 5.1; p = 0.044).

Conclusion

This urban PMTCT programme achieved low transmission rates at six weeks, but LTFU in the first six months limited our ability to examine HIV transmission up to 18 months and determinants of mortality. The LTFU of infants born to women who attended antenatal care at 28 weeks gestation or later emphasizes the need to identify late antenatal attendees for follow up care to educate and support them regarding the importance of follow up care for themselves and their infants.

Total hip arthroplasty (THA) has completely revolutionized the nature in which the arthritic hip is treated, and is considered to be one of the most successful orthopaedic interventions of its generation. With over 100 years of operative history, this review examines the progression of the operation from its origins, together with highlighting the materials and techniques that have contributed to its development. Knowledge of its history contributes to a greater understanding of THA, such as the reasons behind selection of prosthetic materials in certain patient groups, while demonstrating the importance of critically analyzing research to continually determine best operative practice. Finally, we describe current areas of research being undertaken to further advance techniques and improve outcomes.

Previous studies have demonstrated that female reproductive hormones influence chlamydial infection both in vivo and in vitro. Due to the reduced availability of human genital tissues for research purposes, an alternative hormone-responsive model system was sought to study chlamydial pathogenesis. Mature female swine eliminated from breeding programs were selected as the animals of choice because of the similarity of a sexually transmitted disease syndrome and sequelae in swine to a disease syndrome and sequelae found in humans, because of the near identity of a natural infectious chlamydial isolate from swine to Chlamydia trachomatis serovar D from humans, and because a pig's epithelial cell physiology and the mean length of its estrous cycle are similar to those in humans. Epithelial cells from the cervix, uterus, and horns of the uterus were isolated, cultivated in vitro in Dulbecco's minimum essential medium-Hanks' F-12 (DMEM-F-12) medium with and without exogenous hormone supplementation, and analyzed for Chlamydia suis S-45 infectivity. The distribution of chlamydial inclusions in swine epithelial cells was uneven and was influenced by the genital tract site and hormone status. This study confirmed that, like primary human endometrial epithelial cells, estrogen-dominant swine epithelial cells are more susceptible to chlamydial infection than are progesterone-dominant cells. Further, the more differentiated luminal epithelial cells were more susceptible to infection than were glandular epithelial cells. Interestingly, chlamydial growth in mature luminal epithelia was morphologically more active than in glandular epithelia, where persistent chlamydial forms predominated. Attempts to reprogram epithelial cell physiology and thereby susceptibility to chlamydial infection by reverse-stage, exogenous hormonal supplementation were unsuccessful. Freshly isolated primary pig epithelial cells frozen at −80°C in DMEM-F-12 medium with 10% dimethyl sulfoxide for several weeks can, after thawing, reform characteristic polarized monolayers in 3 to 5 days. Thus, primary swine genital epithelia cultured ex vivo appear to be an excellent cell model for dissecting the hormonal modulation of several aspects of chlamydial pathogenesis and infection.

Unlike chlamydial lipopolysaccharide, which is released from the developing inclusion to the surface of infected genital epithelial cells, both Chlamydia trachomatis heat shock protein (hsp) 60 and 70 antigens remained confined within the inclusion during the course of the chlamydial developmental cycle. Exposure of the infected cells to penicillin to induce a persistent infection or to a lipophilic microbicide did not potentiate secretion or exocytosis of the chlamydial hsp.