Chemical mediation of coral larval settlement by crustose coralline algae.

The majority of marine invertebrates produce dispersive larvae which, in order to complete their life cycles, must attach and metamorphose into benthic forms. This process, collectively referred to as settlement, is often guided by habitat-specific cues. While the sources of such cues are well known, the links between their biological activity, chemical identity, presence and quantification in situ are largely missing. Previous work on coral larval settlement in vitro has shown widespread induction by crustose coralline algae (CCA) and in particular their associated bacteria. However, we found that bacterial biofilms on CCA did not initiate ecologically realistic settlement responses in larvae of 11 hard coral species from Australia, Guam, Singapore and Japan. We instead found that algal chemical cues induce identical behavioral responses of larvae as per live CCA. We identified two classes of CCA cell wall-associated compounds--glycoglycerolipids and polysaccharides--as the main constituents of settlement inducing fractions. These algae-derived fractions induce settlement and metamorphosis at equivalent concentrations as present in CCA, both in small scale laboratory assays and under flow-through conditions, suggesting their ability to act in an ecologically relevant fashion to steer larval settlement of corals. Both compound classes were readily detected in natural samples.

Outcome of HIV infected patients on continuous ambulatory peritoneal dialysis.

A retrospective analysis of 39 HIV infected patients with ESRD cared for in New Haven from 1987 to June 1992 was performed. All patients had evidence for HIV infection at the start of CAPD therapy. Cumulative technique survival at one and two years was 43% and 27%, respectively. Only eight patients transferred to center dialysis. One and two year patient survival on CAPD was 58% and 54%, respectively. Mortality was higher in patients with advanced infection than in those with asymptomatic HIV infection. Hospitalization rates were also higher in patients with advanced infection. HIV infected patients had higher rates of peritonitis (3.9 episodes/outpatient CAPD year) compared to non-HIV infected patients (1.5 episodes/CAPD year), especially for pseudomonal and fungal infections. Active injection drug use and use of the "straight set" system were associated with increased rates of peritonitis. CAPD deserves consideration as a therapy for HIV infected patients with ESRD.