Reducing HIV Risk among Transgender Women in Thailand: A Quasi-Experimental Evaluation of the Sisters Program

Transgender women are particularly at risk of HIV infection, but little evidence exists on effective HIV prevention strategies with this population. We evaluated whether Sisters, a peer-led program for transgender women, could reduce HIV risks in Pattaya, Thailand. The study used time-location sampling to recruit 308 transgender women in Pattaya into a behavioral survey in 2011. Coarsened exact matching was used to create statistically equivalent groups of program participants and non-participants, based on factors influencing likelihood of program participation. Using multivariable logistic regression, we estimated effects of any program participation and participation by delivery channel on: condom use at last sex; consistent condom and condom/water-based lubricant use in the past 3 months with commercial, casual, and regular partners; and receipt of HIV testing in the past 6 months. Program coverage reached 75% of the population. In a matched sub-sample (n = 238), participation in outreach was associated with consistent condom/water-based lubricant use with commercial partners (AOR 3.22, 95% CI 1.64–6.31). Attendance at the Sisters drop-in center was associated with receiving an HIV test (AOR 2.58, 95% CI 1.47–4.52). Dedicated transgender-friendly programs are effective at reducing HIV risks and require expansion to better serve this key population and improve HIV prevention strategies.     

Structure of the abdominal receptor responsive to internally applied pressure in the blood-feeding insect,Rhodnius prolixus

Summary The sensory receptor responsive to pressure applied internally to the ventral abdominal body wall of the blood-feeding insects, Rhodnius prolixus, is a single sense cell containing, at its distal end, a cilium enclosed within a scolopale, a densely staining structure characteristic of insect scolopidial sensilla. A small spherical structure lies within a dilation near the midregion of the cilium, and contains nine heavily staining bodies, the position of each corresponding to a pair of microtubules in the cilium. Proximal to the dilation, the microtubules are organized in a ring of nine pairs with one microtubule of each pair associated with dyneinlike arms. Dastal to the dilation a central pair of microtubules is present, but dyneinlike arms are absent. The scolopale cell, which gives risc to the scolopale, has cytoplasmic invaginations that form an elaborate array of extracellular compartments surrounding the body wall of the sense cell. These compartments may serve to dampen high frequency vibrations permitting the receptor to respond to pressure exerted by touch, an attribute in keeping with the receptor's proposed function of detecting abdominal distension related to the size and movement of the stomach.     

Association of the type II cAMP-dependent protein kinase with a human thyroid RII-anchoring protein. Cloning and characterization of the RII-binding domain.

The type II cAMP-dependent protein kinase (PKA) is localized to specific subcellular environments through binding of the dimeric regulatory subunit (RII) to anchoring proteins. Subcellular localization is likely to influence which substrates are most accessible to the catalytic subunit upon activation. We have previously shown that the RII-binding domains of four anchoring proteins contain sequences which exhibit a high probability of amphipathic helix formation (Carr, D. W., Stofko-Hahn, R. E., Fraser, I. D. C., Bishop, S. M., Acott, T. E., Brennan, R. G., and Scott J. D. (1991) J. Biol. Chem. 266, 14188-14192). In the present study we describe the cloning of a cDNA which encodes a 1015-amino acid segment of Ht 31. A synthetic peptide (Asp-Leu-Ile-Glu-Glu-Ala-Ala-Ser-Arg-Ile-Val-Asp-Ala-Val-Ile-Glu-Gln-Val -Lys-Ala-Ala-Tyr) representing residues 493-515 encompasses the minimum region of Ht 31 required for RII binding and blocks anchoring protein interaction with RII as detected by band-shift analysis. Structural analysis by circular dichroism suggests that this peptide can adopt an alpha-helical conformation. Both Ht 31 (493-515) peptide and its parent protein bind RII alpha or the type II PKA holoenzyme with high affinity. Equilibrium dialysis was used to calculate dissociation constants of 4.0 and 3.8 nM for Ht 31 peptide interaction with RII alpha and the type II PKA, respectively. A survey of nine different bovine tissues was conducted to identify RII binding proteins. Several bands were detected in each tissues using a 32P-RII overlay method. Addition of 0.4 microM Ht 31 (493-515) peptide to the reaction mixture blocked all RII binding. These data suggest that all anchoring proteins bind RII alpha at the same site as the Ht 31 peptide. The nanomolar affinity constant and the different patterns of RII-anchoring proteins in each tissue suggest that the type II alpha PKA holoenzyme may be specifically targeted to different locations in each type of cell.     

Methylation patterns at the hypervariable X-chromosome locus DXS255 (M27 beta): correlation with X-inactivation status.

Methylation patterns surrounding a hypervariable X-chromosome locus, DXS255, have been analyzed with the restriction enzyme MspI and its methylation-sensitive isoschizomer HpaII. HpaII sites flanking the hypervariable region were found to be methylated on 41 active X chromosomes and unmethylated on 11 inactive X chromosomes present in a range of male, female, and hybrid cells and tissues. This differential methylation pattern coupled with the previously described high level (greater than 90%) of heterozygosity at the DXS255 locus can therefore be applied to determine the inactivation status of X chromosomes in females heterozygous for X-linked disease and in tumor clonality studies.     

Catalysis by dienelactone hydrolase: A variation on the protease mechanism

Dienelactone hydrolase (DLH), an enzyme from the β-ketoadipate pathway, catalyzes the hydrolysis of dienelactone to maleylacetate. Our inhibitor binding studies suggest that its substrate, dienelactone, is held in the active site by hydrophobic interactions around the lactone ring and by the ion pairs between its carboxylate and Arg-81 and Arg-206. Like the cysteine/serine proteases, DLH has a catalytic triad (Cys-123, His-202, Asp-171) and its mechanism probably involves the formation of covalently bound acyl intermediate via a tetrahedral intermediate. Unlike the proteases, DLH seems to protonate the incipient leaving group only after the collapse of the first tetrahedral intermediate, rendering DLH incapable of hydrolyzing amide analogues of its ester substrate. In addition, the triad His probably does not protonate the leaving group (enolate) or deprotonate the water for deacylation; rather, the enolate anion abstracts a proton from water and, in doing so, supplies the hydroxyl for deacylation. © 1993 Wiley-Liss, Inc.