Simulation of time-resolved breast transillumination

A Monte Carlo simulation has been developed to predict the quality of time-resolved images of the breast by transillumination. The smallest diameter of a detectable carcinoma located in the breast has been computed. The simulation suggests that time-resolved imaging of the breast is possible and invaluable in the near infra-red (NIR) by transillumination. The enhancement of the transfer function by the introduction of time-resolved detection is limited by the contribution of noise at short integration times. The estimated diameter of the smallest detectable sphere is derived from the image quality index (IQI) theory and its value is around 4 mm. The simulated images of an absorbing sphere (approximating the carcinoma) within a homogeneous medium (approximating the surrounding tissue) show a significant improvement of the image with short integration time.     

The Genetics of Obesity: What Have Genetic Studies Told Us About the Environment

Genetic studies have shown that both childhood and adult body mass index are substantially heritable. The evidence for shared family environmental influences is largely absent, even though there are clear indications that secular changes in energy expenditure have brought about a significant increase in the prevalence of obesity. This apparent inconsistency may be explained by the dual phenomena of the near-universality of access to environments that facilitate reductions in energy expenditure (e.g., TV as a recreational pastime), together with heritable individual differences in the response to or utilization of these environments. The impact of changes in nonshared environments on body weight can be estimated from biometrical genetical studies and is found to be both small and relatively short-lived. Genetic and environmental results from longitudinal studies are consistent with what is known about the changing distribution of adiposity during adulthood and clinical experience of the difficulty of maintaining behavioral-induced weight loss.     

Changes in circulating blood volume following isoflurane or sevoflurane anesthesia

Changes of circulating blood volume (CB volume) measured by the dual indicator dilution method were observed in 33 chronically instrumented mongrel dogs following either alpha-chloralose-urethane (C group), additive isoflurane (I group) or sevoflurane anesthesia (S group). These anesthetic groups were each divided into two subgroups with regard to respiratory care, namely Cp, Ip and Sp for those with intermittent positive pressure ventilation (six animals per subgroups), and Cs, Is and Ss for those with spontaneous breathing (five animals per subgroups).The CB volume under positive pressure ventilation remained unchanged in the Ip and Sp groups at both 0.5 and 1.0 MAC, and in the Cp group. The CB volume remained essentially unchanged in the Cs and Is groups at both 0.5 or 1.0 MAC, but the plasma volume tended to increase slightly in the Is group at 1.0 MAC.In the Ss group under spontaneous breathing, however, the CB volume increased from 84.4 ± 7.0 to 91.4 ± 7.7 at 0.5 MAC, and to 91.4 ± 10.2ml·kg^–1 at 1.0 MAC (0.01 P 0.05). These increases were caused by an increase in the plasma volume.The above data suggests that a concomitant increase in the venous pressure associated with an increase in the intrathoracic pressure produced by positive pressure ventilation would attenuate changes in the CB volume during sevoflurane anesthesia.(Hamada H, Takaori M, Kimura K, et al.: Changes in circulating Blood volume following isoflurane or sevoflurane anesthesia. J Anesth 7: 316–324, 1993)     

低心室容量负荷未能影响兔离体心肌的氧耗反应时间

为了解心肌容量负荷是否影响心肌的氧化磷酸化过程,采用兔离体灌流心肌线粒体氧耗反应时间测定方法,对一下正常心室容量负荷和低心室容量负荷时的心肌线粒体氧耗反应时间进行比较,结果提示心肌作功负荷变化未能影响心肌线粒体的能量代谢动态调节过程。     

脑血管病危险因素在海口城乡对比的调查

目的 通过脑血管病危险因素在海口城乡对比的调查,了解脑血管病发病的相关因素。方法 以整群随机抽样法,从超过４０岁人群中取城市１９２人,农村２３１人进行测定血糖、血甭胆固醇、苷油三酯、高密度脂蛋白、低密度脂蛋白、极低密度脂蛋白。结果 经统计学处理,发现胆固醇、苷油三酯高、低密度脂蛋白、极低密度脂蛋白、极低密度脂蛋白城乡比较均有显著差异（Ｐ〈０．０１）,脑血管病发病率、死亡率,城市明显高于乡村（Ｐ〈０