Interventions among male clients of female sex workers in Benin, West Africa: an essential component of targeted HIV preventive interventions.

OBJECTIVES: To assess the impact of interventions targeted towards female sex workers (FSWs) and their male clients on client HIV/STI prevalence and sexual behaviour. METHODS: From 1993 to 2006, an HIV/STI preventive intervention focusing on condom promotion and STI care was implemented among FSWs in Cotonou, Benin, and then expanded to cover their male sexual partners in 2000. The interventions were scaled up to five other cities of Benin in 2001-2002. Serial cross-sectional surveys of HIV/STI prevalence and sexual behaviour were carried out among clients in Cotonou in 1998, 2002 and 2005; and in the five other cities (O/Cotonou) in 2002 and 2005. RESULTS: Significant declines in gonorrhoea prevalence among clients of FSWs: Cotonou, from 5.4% in 1998 to 1.6% in 2005; O/Cotonou: from 3.5% in 2002 to 0.59% in 2005. Chlamydia prevalence also declined O/Cotonou, from 4.8% to 1.8%, while HIV prevalence remained stable. Reported condom use by clients with both FSWs and casual non-FSW partners, but not regular partners, increased significantly. While condom use at last sex with an FSW was similar in Cotonou to O/Cotonou around the time of implementation of the interventions (56% in 1998 vs 49% in 2002, respectively), it had risen to similar levels by 2005 (95% and 96%, respectively). CONCLUSIONS: These results demonstrate that it is possible to implement preventive and clinical services for clients of FSWs, and suggest that such interventions, integrated with those targeted towards FSWs, can have a significant effect on sexual behaviour and STI prevalence (particularly gonorrhoea) among this population.

Postnatal development of electrophysiological properties of nucleus accumbens neurons.

We have studied the postnatal development of the physiological characteristics of nucleus accumbens (nAcb) neurons in slices from postnatal day 1 (P1) to P49 rats using the whole cell patch-clamp technique. The majority of neurons (102/108) were physiologically identified as medium spiny (MS) projection neurons, and only these were subjected to detailed analysis. The remaining neurons displayed characteristics suggesting that they were not MS neurons. Around the time of birth and during the first postnatal weeks, the membrane and firing characteristics of MS neurons were quite different from those observed later. These characteristics changed rapidly during the first 3 postnatal weeks, at which point they began to resemble those found in adults. Both whole cell membrane resistance and membrane time constant decreased more than fourfold during the period studied. The resting membrane potential (RMP) also changed significantly from an average of -50 mV around birth to less than -80 mV by the end of the third postnatal week. During the first postnatal week, the current-voltage relationship of all encountered MS neurons was linear over a wide range of membrane potentials above and below RMP. Through the second postnatal week, the proportion of neurons displaying inward rectification in the hyperpolarized range increased steadily and after P15, all recorded MS neurons displayed significant inward rectification. At all ages, inward rectification was blocked by extracellular cesium and tetra-ethyl ammonium and was not changed by 4-aminopyridine; this shows that inward rectification was mediated by the same currents in young and mature MS neurons. MS neurons fired single and repetitive Na(+)/K(+) action potentials as early as P1. Spike threshold and amplitude remained constant throughout development in contrast to spike duration, which decreased significantly over the same period. Depolarizing current pulses from rest showed that immature MS neurons fired action potentials more easily than their older counterparts. Taken together, the results from the present study suggest that young and adult nAcb MS neurons integrate excitatory synaptic inputs differently because of differences in their membrane and firing properties. These findings provide important insights into signal processing within nAcb during this critical period of development.