Bioimpedance Analysis Parameters and Epicardial Adipose Tissue Assessed by Cardiac Magnetic Resonance Imaging in Patients With Heart Failure

There is increasing evidence that body composition should be considered as a systemic marker of disease severity in congestive heart failure (CHF). Prior studies established bioelectrical impedance analysis (BIA) as an objective indicator of body composition. Epicardial adipose tissue (EAT) quantified by cardiac magnetic resonance (CMR) is the visceral fat around the heart secreting various bioactive molecules. Our purpose was to investigate the association between BIA parameters and EAT assessed by CMR in patients with CHF. BIA and CMR analysis were performed in 41 patients with CHF and in 16 healthy controls. Patients with CHF showed a decreased indexed EAT (22 ± 5 vs. 34 ± 4 g/m², P < 0.001) and phase angle (PA) (5.5° vs. 6.4°, P < 0.02) compared to healthy controls. Linear regression analysis showed a significant correlation of CMR indexed EAT with left ventricular ejection fraction (LV‐EF) (r = 0.56, P < 0.001), PA (r = 0.31, P = 0.01), total body muscle mass (TBMM) (r = 0.41, P = 0.001), fat‐free mass (FFM) (r = 0.30, P = 0.02), and intracellular water (ICW) (0.47, P = 0.0003). Multivariable analysis demonstrated that LV‐EF was the only independent determinant of indexed EAT (P < 0.0001). Receiver operating characteristic curve analysis indicated good predictive performance of PA and EAT (area under the curve (AUC) = 0.86 and 0.82, respectively) with respect to cardiac death. After a follow‐up period of 5 years, 8/41 (19.5%) patients suffered from cardiac death. Only indexed EAT <22 g/m² revealed a statistically significant higher risk of cardiac death (P = 0.02). EAT assessed by CMR correlated with the BIA‐derived PA in patients with CHF. EAT and BIA‐derived PA might serve as additional prognostic indicators for survival in these patients. However, further clinical studies are needed to elucidate the prognostic relevance of these new findings.     

Possible cooperativity in crossbridge detachment in muscle fibers having magnesium pyrophosphate at the active site.

When rabbit psoas muscle fibers bathed in solutions containing the ATP analogue magnesium pyrophosphate (MgPPi) are first stretched rapidly and then held isometric, a force is generated during the stretch which decays during the subsequent isometric period (Schoenberg, M., and E. Eisenberg. 1985. Biophys. J. 48:863-871). Previously we showed that the force decay is due to crossbridge heads detaching and reattaching in positions of lesser strain, the rate of decay of force reflecting the crossbridge detachment rate constants. Since the crossbridge detachment rate constants with MgPPi bound to the active site are so much faster than without analogue bound, at subsaturating concentrations of analogue, if the heads act independently and nucleotide association and dissociation is rapid, the rate of force decay should simply be proportional to the number of heads with bound analogue. That is, the analogue concentration dependence of the rate of force decay should have the same form as the Michaelis-Menten equation. Here we report that the concentration dependence of the rate of force decay is not described by the Michaelis equation, but is instead sigmoidal. This suggests possible cooperativity in the detachment of the crossbridge heads, the amount of cooperativity being described by an interaction coefficient of approximately 2. One idea put forward to explain the data is that both of the heads of a crossbridge may need to bind analogue before the crossbridge can relax a substantial fraction of the tension it supports.     

Temporal dynamics and spatial variation of algae in relation to hydrology and sediment characteristics in the Okefenokee Swamp,Georgia

In a 20-month study, phytoplankton and periphyton chl a, and dry mass of macroscopic algal aggregates in four marshes and a lake within the Okefenokee Swamp (Georgia, USA) were comparable to other wetlands and lake littoral areas. Chlorophyll levels in two marshes were inversely related to water level and phytoplankton at three marshes developed unimodal maxima following macrophyte dieback. Standing stocks in a vernally inundated marsh were greater than a nearby marsh which was permanently inundated; chlorophyll levels displayed longer blooms in the inundated marsh during periods of low rainfall or after drought. Field dynamics, sediment sorption characteristics and algal bioassays suggest that evaporative drawdown stimulates algae by release of nutrients from exposed peat, while high water levels reduce nutrient release from sediments and disperse phytoplankton through flushing. Equilibrium phosphate concentrations of sediments and algal levels were higher at an abandoned rookery than a nearby non-rookery area, indicating nutrient enrichment from residual guano deposits.     

Identification and characterization of a cDNA encoding ribosomal protein S12 from Xenopus laevis

The complete nucleotide (nt) sequence of the cDNA clone XL-S12, encoding a Xenopus laevis (XI) homologue of the mammalian ribosomal protein S12, has been determined. The sequence predicts a XI S12 protein of 132 amino acids (aa) with a molecular mass of 14.7 kDa. XI S12 shares 95 and 97% aa sequence identity with the human and murine S12 proteins, respectively. Analysis of nt substitution patterns and rates indicates that S12 is a very highly constrained protein, evolving at an estimated rate of only 0.03 x 10˜9 non-synonymous (protein-altering) substitutions per site per year.     

Position and sequence requirements for poly(A) length regulation by the poly(A) limiting element.

The poly(A)-limiting element (PLE) is a cis-acting sequence that acts to limit poly(A) tail length on pre-mRNA to <20 nt. Functional PLEs are present in a number of genes, underscoring the generality of this control mechanism. The current study sought to define further the position requirements for poly(A) length regulation and the core sequence that comprises a PLE. Increasing the spacing between the PLE and the upstream 3' splice site or between the PLE and the downstream AAUAAA had no effect on poly(A) length control. However, moving the PLE from the terminal exon to either an upstream exon or intron eliminated poly(A) length control. Poly(A) length control was further evaluated using a battery of constructs in which the PLE was maintained in the terminal exon, but where upstream introns were either deleted, modified, or replaced with a polypyrimidine tract. Poly(A) length control was retained in all cases, indicating that the key feature is the presence of the PLE in the terminal exon. A battery of mutations demonstrated the importance of the 5' pyrimidine-rich portion of the element. Finally, UV crosslinking experiments identified an approximately 62-kDa protein in Hela nuclear extract that binds to a wild-type 23-nt PLE RNA oligonucleotides but not to a mutated nonfunctional form of the element.     

Body image among older,rural, African-American women with type 2 diabetes

Type 2 diabetes and obesity co-occur in high prevalence among African-American women. The positive value placed on large body size has both historic and contemporary biosocial relevance. The maintenance of weight at medically recommended levels is a cornerstone of both prevention and treatment of Type 2 diabetes. This study of overweight, elderly, rural African-American women with Type 2 diabetes found they generally preferred smaller body sizes compared to previous studies. Normal to slim body images as presented in a photographic array were selected as being more attractive, less likely to have diabetes and hypertension, healthier and to be more medically compliant than obese, grossly obese or very thin images. Body image is a psychosocial variable that should be included in weight control initiatives.