Protease inhibitors and cardiovascular outcomes in patients with HIV-1

Protease inhibitors for treatment of HIV-1 have been linked with increased risk of hyperlipidaemia and hyperglycaemia. In a cohort of 5672 outpatients with HIV-1 seen at nine US HIV clinics between January, 1993, and January, 2002, the frequency of myocardial infarctions increased after the introduction of protease inhibitors in 1996 (test for trend, p=0.0125). We noted that 19 of 3247 patients taking, but only two of 2425 who did not take, protease inhibitors had a myocardial infarction (odds ratio 7.1, 95% CI 1.6-44.3; Cox proportional hazards model-adjusted for smoking, sex, age, diabetes, hyperlipidaemia, and hypertension-hazard ratio 6.5, 0.9-47.8). Our findings suggest that, although infrequent, use of protease inhibitors is associated with increased risk of myocardial infarction in patients with HIV-1.     

Msx1 and Msx2 are functional interacting partners of T-box factors in the regulation of Connexin43

AIMS: T-box factors Tbx2 and Tbx3 play key roles in the development of the cardiac conduction system, atrioventricular canal, and outflow tract of the heart. They regulate the gap-junction-encoding gene Connexin43 (Cx43) and other genes critical for heart development and function. Discovering protein partners of Tbx2 and Tbx3 will shed light on the mechanisms by which these factors regulate these gene programs. METHODS AND RESULTS: Employing an yeast 2-hybrid screen and subsequent in vitro pull-down experiments we demonstrate that muscle segment homeobox genes Msx1 and Msx2 are able to bind the cardiac T-box proteins Tbx2, Tbx3, and Tbx5. This interaction, as that of the related Nkx2.5 protein, is supported by the T-box and homeodomain alone. Overlapping spatiotemporal expression patterns of Msx1 and Msx2 together with the T-box genes during cardiac development in mouse and chicken underscore the biological significance of this interaction. We demonstrate that Msx proteins together with Tbx2 and Tbx3 suppress Cx43 promoter activity and down regulate Cx43 gene activity in a rat heart-derived cell line. Using chromatin immunoprecipitation analysis we demonstrate that Msx1 can bind the Cx43 promoter at a conserved binding site located in close proximity to a previously defined T-box binding site, and that the activity of Msx proteins on this promoter appears dependent in the presence of Tbx3. CONCLUSION: Msx1 and Msx2 can function in concert with the T-box proteins to suppress Cx43 and other working myocardial genes.     

Architectural plan for the heart: early patterning and delineation of the chambers and the nodes

During folding of the embryo, lateroanterior visceral mesoderm forms the embryonic tubular heart at the midline, just ventral to the foregut. In mice, this nascent tube contains the future left ventricle and atrioventricular canal. Mesenchymal cells subsequently recruited to the cardiac lineage at the intake and the outflow of the tube will form the atria and the right ventricle and outflow tract, respectively. Shortly after its emergence, the embryonic heart tube starts to loop, and the first signs of left ventricular chamber differentiation become visible on the outer curvature of the middle portion of the tube. Subsequently, the right ventricle differentiates cranially, and the atria caudally, while the inflow tract, atrioventricular canal, inner curvatures, and outflow tract form recognizable components flanking the chambers. The latter, nonchamber regions in turn provide signals for the formation of the cushion mesenchyme, are involved in remodeling of the heart, and form the nodes of the conduction system. This review discusses how the patterning of the heart tube relates to the localized differentiation of atrial and ventricular chambers, why some parts of the heart do not form chambers, and how this relates to the formation of the conduction system.     

Late onset Ommaya reservoir infection due to Staphylococcus aureus: case report and review of Ommaya Infections

The Ommaya reservoir system has been used for the treatment of chronic central nervous system infections and intracranial tumors for more than three decades. The majority of reported Ommaya reservoir infections occur proximate to the time the device is accessed. A review of the literature reveals that late onset of reservoir infection is quite rare. We report a case of Ommaya reservoir infection due to Staphylococcus aureus that was diagnosed seven years after its insertion and usage for intracerebral non-Hodgkin's lymphoma and review the literature on the microbiology and management of Ommaya reservoir infections.