Impact of Body Mass Index on Left Ventricular Function

Background

Obesity is associated with increased cardiovascular morbidity and mortality. A direct effect of isolated obesity on cardiac function is not well established. The study was designed to determine the direct effect of various grades of isolated obesity on echocardiographic indices of systolic and diastolic left ventricular function.

Methods

Fifty one obese and 25 normal weight, serving personnel without any other pathological condition were studied. Group I (n=25) consisted of subjects with normal weight and body mass index (BMI <25kg/m²), Group II (n=34) of overweight subjects (BMI 25-29.9 kg/m²) and Group III (n=17) of obese subjects (BMI >30 kg/m²). Echocardiographic indices of systolic and diastolic function were obtained and dysfunction was assumed when at least two values differed by ≥ 2 SD from the normal weight group.

Result

Ejection fraction, fractional shortening were increased (p<0.05) in Group II and III. Left ventricular dimensions were increased (p< 0.001) but relative wall thickness was unchanged. Systolic dysfunction was not observed in any of the obese patients. The mitral valve pressure half time (p< 0.01), left atrial diameter (p < 0.01) and the deceleration time were increased (p< 0.01) in obese subjects, while other diastolic variables were unchanged. No difference were found between obesity subgroups. Subclinical diastolic dysfunction was more prevalent among obese subjects. BMI correlated significantly with indices of left ventricular systolic and diastolic function.

Conclusion

Subclinical left ventricular diastolic dysfunction was noted in all grades of obesity which correlates with BMI.Key Words: Obesity, Systolic function, Diastolic function, Echocardiography     

Causal entropies--a measure for determining changes in the temporal organization of neural systems

We propose a novel measure to detect temporal ordering in the activity of individual neurons in a local network, which is thought to be a hallmark of activity-dependent synaptic modifications during learning. The measure, called causal entropy, is based on the time-adaptive detection of asymmetries in the relative temporal patterning between neuronal pairs. We characterize properties of the measure on both simulated data and experimental multiunit recordings of hippocampal neurons from the awake, behaving rat, and show that the metric can more readily detect those asymmetries than standard cross correlation-based techniques, especially since the temporal sensitivity of causal entropy can detect such changes rapidly and dynamically.     

Evaluation of perilymphatic fistulas by middle ear endoscopy.

Transtympanic endoscopy provides a unique opportunity to view the undisturbed contents of the middle ear. Fiberoptic and rigid endoscopes have been used for thorough examination of the middle ear without the need for local anesthetics or surgical trauma. Endoscopy is now routinely used in the evaluation of a perilymphatic fistula and the patient is awake during an intermittent forceful Valsalva maneuver. Oval and round windows in both ears of five cats were studied endoscopically to evaluate surgically created fistulas. Excellent visualization of the defect was obtained in all instances. Endoscopy is a useful office technique for the evaluation of perilymphatic fistula. It reduces the need for surgical exploration and provides a satisfactory examination of the middle ear. Obliteration of the window niche can even be performed through the myringotomy using autologous blood.     

运动对铁吸收的影响及其作用途径

目的:综合分析运动对铁吸收的影响及其作用途径。资料来源:检索Pubmed1950-01/2006-04有关运动对铁吸收的影响及其作用途径的文献,检索词为“iron absorption,iron metabolism,exercise”。同时检索万方数据库1994-01/2006-03有关运动对铁吸收的影响及其作用途径的文献,检索词为“铁吸收,铁代谢,运动”。资料选择:初选后,有关铁吸收、运动对铁吸收影响及其调节机制的文献被选中。发表于2002年后的文献被优先选择,排除重复实验和Meta分析。资料提炼:检索到9000篇文献,大部分是关于铁吸收调节机制的文献,其中40篇有关运动和铁吸收及其调节机制,30篇作为代表性研究文献被引用。资料综合:运动可导致低铁状态,影响运动能力,这种低铁状态的形成及其调节与铁吸收相关。但是,对于运动如何影响铁吸收存在两种截然相反的观点,一种观点认为运动促进铁吸收;另一种观点认为运动降低铁吸收。最近的研究已经显示运动可能通过机体铁水平、一氧化氮、Hepcidin、促红细胞生成素、低氧以及基因突变(如HFE突变)调节铁吸收。结论:有关运动影响铁吸收的研究仍是初步的,在运动情况下如何调节铁吸收尚有待研究,这对于进一步分析运动诱导的低铁状态的本质以及运动员和运动健身人群是否需要以及如何补充铁具有重要意义。     

X型胶原蛋白与骨骼生长发育关系的研究进展

X型胶原是近年来发现的一种新型胶原,它只存在于生长发育期的即将骨化的软骨内,以液态均相的形式分布于细胞外基质,并启动软骨骨化。它具有特异性合成、局限性分布、一过性存在的特征。许多骨骼系统疾病与X型胶原的异常有着密切的关系。     

Apoptosis in peripheral lymphocytes in systemic lupus erythematosus: a review

There is increasing evidence to suggest that abnormalities in apoptosis may play a part in the pathogenesis of systemic lupus erythematosus (SLE). For example, there is now considerable evidence that bel-2 expression is enhanced in a proportion of peripheral T cells, but not in B cells, in SLE patients and correlates with overall disease activity regardless of the activity index employed. Further work is required to establish whether enhanced bel-2 expression by some T cells in SLE patients is related to their activation or intrinsically enhanced by genetic predisposition. Mutations in Fas result in a lymphoproliferative syndrome and may play a role in accelerating autoimmune disease. A report of three children with mutations in Fas has once again focused attention on this regulator of apoptosis. The relationships between inducers and inhibitors of apoptosis may differ in different cell types, and must be elucidated before the implications of observations made in lymphocytes from SLE patients can be fully understood.