女人更怕冷

寒冷的冬李,低温、大风等气象因素加快了人体的热量散失,肌肤、器官、心理就会有些不适,这就是通常说的“怕冷”。比较起来,女人比男人更加怕冷。这其中自然有主观方面的因素(比如,女人多爱撒娇、意志力不强、为追求体形而刻意节食等),但更多的却是生理方面的原因。传统中医认为,人之所以怕冷,是因为“人体阳气丧微,     

In vitro fluorescence displacement investigation of thyroxine transport disruption by bisphenol A

Bisphenol A (BPA) is a chemical with high production volume and wide applications in many industries. Although BPA is known as an endocrine disruptor, its toxic mechanisms have not been fully characterized. Due to its structural similarity to thyroid hormones thyroxine (T4) and triiodothyronine (T3), one possible mechanism of BPA toxicity is disruption of hormone transport by competitive binding with the transport proteins. In this study, the binding interactions of BPA, T4, and T3 with three thyroid hormone transport proteins, human serum albumin (HSA), transthyretin (TTR), and thyroxine-binding globulin (TBG) were investigated by fluorescence measurement. Using two site-specific fluorescence probes dansylamide and dansyl-L-proline, the binding constants of BPA with HSA at drug site I and site II were determined as 2.90 104 and 3.14 104 L/mol, respectively. By monitoring the intrinsic fluorescence of tryptophan, a binding constant of 4.70 103 L/mol was obtained. Similarly, by employing 8-anilino-1-naphthalenesulfonic acid as fluorescence probe, the binding a nity of BPA with TTR and TBG was measured to be 3.10 105 and 5.90 105 L/mol, respectively. In general, BPA showed lower binding a nity with the proteins than T3 did, and even lower a nity than T4. Using these binding constants, the amount of BPA which would bind to the transport proteins in human plasma was estimated. These results suggest that the concentrations of BPA commonly found in human plasma are probably not high enough to interfere with T4 transport.     

环境激素对人类健康的影响

在人工合成化学品日益繁多的今天,环境激素因其对动植物以及人类健康的威胁而倍受关注。环境激素在环境中普遍存在,不仅对生物的繁殖具有一定影响,而且还对生物的许多行为和感知能力产生影响。本文简述了环境激素的概念、特点和分类,总结了环境激素对人类健康的危害,并阐述了其作用产生机理,探讨了环境激素物质的控制措施。     

秋意渐浓防秋愁

自古有“伤春悲秋”的说法。让人产生悲伤情绪的是一种激素,叫“褪黑激素”,它不但让人抑郁,还能让人入睡,是由我们大脑底部一个叫松果体的腺体产生的。充足的阳光可以抑制褪黑激素的分泌。但入秋后,阳关照射时间明显减少,特别秋天多雨,人体的褪黑激素就会增多,同时甲状腺素、肾上腺素的分泌会受到抑制,细胞也就会“懈工偷懒”,人的情绪...     

羟基多溴代二苯醚与甲状腺素运载蛋白相互作用的3D-QSAR研究

近年来,羟基多溴代二苯醚(OH-PBDEs)的类甲状腺素效应逐渐引起人们的关注,然而其结构效应关系和致毒机制尚不清楚。甲状腺激素结合球蛋白(TBG)和运甲状腺素蛋白(TTR)是人体转运甲状腺素的重要蛋白,通过计算毒理学手段可以揭示OH-PBDEs的微观毒理机制。利用分子对接技术研究OH-PBDEs与TBG、TTR的结合模式和构象特征,识别关键氢键氨基酸为赖氨酸Lys270(TBG),亮氨酸Leu110(TTR)和丝氨酸Ser117(TTR)。基于活性构象特征,构建14种典型OH-PBDEs的3D-QSAR模型,定量预测OH-PBDEs与TBG、TTR的结合亲和力。最佳预测模型的相关系数r2分别为0.966(TBG)和0.961(TTR),抽一法交叉验证相关系数q2分别为0.560(TBG)和0.525(TTR)。研究发现,OH-PBDEs的静电和氢键作用可增强结合亲和力,分别贡献65.4%(TBG)和68.7%(TTR)。研究结果为揭示OH-PBDEs与甲状腺素转运蛋白的相互作用提供新视角,有助于全面评价OH-PBDEs对人体甲状腺素调节功能的损伤。