OBJECTIVESeveral pathomechanisms are implicated in the pathogenesis of metabolic syndrome (MetS), most of which have not been investigated in African Americans (AAs). We examined the contribution of a selected panel of biomarkers to the development of MetS in Jackson Heart Study (JHS) participants in this investigation.RESEARCH DESIGN AND METHODSWe evaluated 3,019 JHS participants (mean age, 54 years; 64% women) with measurements for seven biomarkers representing inflammation (high-sensitivity C-reactive protein [CRP]), adiposity (leptin), natriuretic pathway (B-natriuretic peptide [BNP]), adrenal pathway (cortisol and aldosterone), and endothelial function (endothelin and homocysteine). We related the biomarker panel to the development of MetS on follow-up and to longitudinal changes in MetS components.RESULTSThere were 278 (22.9%) of 1,215 participants without MetS at baseline who had development of new-onset MetS at follow-up. The incidence of MetS was significantly associated with serum aldosterone (P = 0.004), CRP (P = 0.03), and BNP (P for trend = 0.005). The multivariable-adjusted odds ratios (95% CI) per SD increment of log biomarker were as follows: 1.25 (1.07–1.45) for aldosterone, 1.20 (1.02–1.43) for CRP, and 1.54 (1.07–2.23) and 1.91 (1.31–2.80) for low and high BNP quartiles, respectively. Aldosterone was positively associated with change in all MetS risk components, except low HDL cholesterol and waist circumference. CRP concentration was significantly and directly associated with change in systolic blood pressure (SBP) and waist circumference but inversely associated with HDL cholesterol. For BNP, we observed a U-shape relation with SBP and triglycerides.CONCLUSIONSOur analysis confirms that, in AAs, higher circulating aldosterone and CRP concentrations predict incident MetS. The nonlinear U-shape relation of BNP with MetS and its components has not been reported before and thus warrants replication.
Gawalapu, Ravi Kumar. Fluorescence labeling and computational analysis of the strut of myosin's 50 kDa cleft. Doctor of Philosophy (Biochemistry), August 2007, 148 pp., 3 tables, 60 illustrations, 120 references, 120 titles.In order to understand the structural changes in myosin S1, fluorescence polarization and computational dynamics simulations were used. Dynamics simulations on the S1 motor domain indicated that significant flexibility was present throughout the molecular model. The constrained opening versus closing of the 50 kDa cleft appeared to induce opposite directions of movement in the lever arm. A sequence called the "strut" which traverses the 50 kDa cleft and may play an important role in positioning the actomyosin binding interface during actin binding is thought to be intimately linked to distant structural changes in the myosin's nucleotide cleft and neck regions. To study the dynamics of the strut region, a method of fluorescent labeling of the strut was discovered using the dye CY3. CY3 served as a hydrophobic tag for purification by hydrophobic interaction chromatography which enabled the separation of labeled and unlabeled species of S1 including a fraction labeled specifically at the strut sequence. The high specificity of labeling was verified by proteolytic digestions, gel electrophoresis, and mass spectroscopy.Analysis of the labeled S1 by collisional quenching, fluorescence polarization, and actinactivated ATPase activity were consistent with predictions from structural models of the probe's location. Although the fluorescent intensity of the CY3 was insensitive to actin binding, its fluorescence polarization was notably affected. Intriguingly, the mobility of the probe increases upon S1 binding to actin suggesting that the CY3 becomes displaced from interactions with the surface of S1 and is consistent with a structural change in the strut due to cleft motions. Labeling the strut reduced the affinity of S1 for actin but did not prevent actin-activated ATPase activity which makes it a potentially useful probe of the actomyosin interface. The different conformations of myosin S1 indicated that the strut is not as flexible as several other key regions of myosin as determined by the application of force constraints to elastic portions of the myosin
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