Development and Preliminary Pilot Testing of a Peer Support Text Messaging Intervention for HIV-Infected Black Men Who Have Sex With Men.

BACKGROUND: Black men who have sex with men (MSM) are disproportionately infected with HIV and are less well retained along the HIV continuum of care. We report on the feasibility of a peer support text messaging intervention designed to increase retention in HIV care and HIV medication adherence among HIV-infected black men who have sex with men. METHODS: Based on formative research, a cell phone app was developed to support a peer-based text messaging intervention. The app allowed the researchers to view text messages sent between mentors and mentees, but did not allow them to view other text messages sent by these phones. Three HIV-infected black men who have sex with men were recruited to serve as volunteer peer mentors. They were trained in motivational techniques, peer support skills, and skills for improving appointment attendance and medication adherence. Mentees (N = 8) received the intervention for 1 month. Mentees completed a postintervention survey and interview. RESULTS: The peer mentor text messaging intervention was feasible. Mentors delivered support in a nonjudgmental, motivational way. However, technical and other implementation problems arose. Some mentees desired more frequent contact with mentors, and mentors reported that other commitments made it difficult at times to be fully engaged. Both mentors and mentees desired more personalized contact (ie, phone calls). CONCLUSIONS: A text messaging peer mentor intervention was feasible. Additional research with a larger sample is needed to determine optimal ways to improve mentors' engagement in the intervention and to determine intervention acceptability and efficacy. In future studies, peer support phone calls could be incorporated.

Characterization of an aldolase-dehydrogenase complex that exhibits substrate channeling in the polychlorinated biphenyls degradation pathway.

An aldolase and dehydrogenase complex from the polychlorinated biphenyl degradation pathway of the bacterium Burkholderia xenovorans LB400 was purified. The aldolase, BphI, had the highest activity with Mn(2+) as the cofactor and was able to transform 4-hydroxy-2-oxopentanoate and 4-hydroxy-2-oxohexanoate to pyruvate and acetaldehyde or propionaldehyde with similar specificity constants. Aldolase activity was competitively inhibited by the pyruvate enolate analogue, oxalate, with a K(ic) of 0.93 microM. The pH-rate profiles suggested the involvement of a pK(a) 7.7 catalytic base in the reaction mechanism. BphI activity was activated 15-fold when substrate turnover was occurring in the dehydrogenase, BphJ, which can be attributed partially to nicotinamide coenzyme binding to BphJ. BphJ had similar specificity constants for acetaldehyde or propionaldehyde and was able to utilize aliphatic aldehydes from two to five carbons in length as substrates, although K(m) values for these aldehyes were >20 mM. When 4-hydroxy-2-oxopentanoate was provided as a substrate to the BphI-BphJ complex in a coupled enzyme assay, no lag in the progress curve of BphJ was observed. When 1 mM propionaldehyde was added exogenously to a reaction mixture containing 0.1 mM 4-hydroxy-2-oxopentanoate, 95% of the CoA esters produced was acetyl CoA. Conversely, 99% of the CoA esters produced was propionyl CoA when a 10-fold molar excess of exogenous acetaldehyde was added in a reaction mixture containing 4-hydroxy-2-oxohexanoate. These results demonstrate that acetaldehyde and propionaldehyde, products of the BphI reaction, are not released in the bulk solvent but are channeled directly to the dehydrogenase.