老年性痴呆与酶缺少有关

长期以来,引起老年性痴呆最常见的疾病,Alzheimer's病(简称AD),不知损害了多少老年人的头脑和智力,而医生对此却无能为力。然而最近,巴尔的摩的神经科学家们已经掌握了充分的证据认为,AD的发生与脑内控制注意力、学习和记忆功能的区域中某些酶的不足有关。这一可喜的进展给患者和医生带来了希望和光明。据美国“科学”杂志(Vol219,p1184)报道,约翰霍普金斯医学院的科学家,De Long等已经发现了第一例、由某些特定的神经递质和神经通路     

表观遗传驱动着表型?

Katsnelson等识别出一种无编码蛋白的DNA区域仍能够决定表型的某些特征（身高、对某种疾病的易感）的机制。科学家们发现某些染色质的修饰常赋有表观遗传的意义，不受基因序列调节，事实上由个体的DNA决定。此外，这些染色质变异常伴有不同的单核苷酸多态性（SNP），提示此变异可能是使这些SNPs（常见于DNA无编码区域）影响表型的一个平台。     

从血管生物学的一些研究看心肌梗塞的发病机制

1912年Herrick提示冠脉急性血栓形成造成AMI。但60年代对血栓的作用大加质疑。到了1980年DeWood等说明大多数心梗的十分早期事件是冠脉血栓形成,溶栓疗法由此蓬勃发展。但冠状动脉血栓何以只发生于某些个体,发生于动脉粥样硬化的某些区域?     

慢性心力衰竭的认知障碍流行病学研究进展

反映学习和记忆的认知功能是大脑高级神经活动的表现,认知障碍是由于某些疾病等原因导致认知功能(学习和记忆等神经行为学)出现损伤的表现.     

虚拟仿真在基于PBL流行病学教学中的应用初探

将虚拟仿真应用于"以问题为基础的学习"(PBL)的流行病学教学模式当中,克服传统教学以理论为主、某些高危险性传染病不能进行实际现场教学的缺点。通过两种教学形式的融合,培养学生自主学习、发现问题和人际交流的能力,强化流行病学实践操作技能,提高医学生综合素质。     

毒物兴奋效应与抗衰老研究

某些毒物在低剂量时对生物体的刺激导致反馈改善的现象,简称“毒物兴奋效应”。是一个近年发展兴起的生物细胞及生物体抗应激、抗衰老研究的新领域,其分子机制正在被逐步阐明。某些轻微的生物应激如：热应激、重力应激、运动应激、损伤应激及限食应激等,也能在生物体内产生一连串的级联放大效应,进而诱发多种协同的和多效的分子作用,从而对机体健康产生反馈保护的效果。由于导致机体防御能力的增加和大分子损伤的减少,毒物兴奋效应在生命平衡系统中起到了重要的“疫苗样”作用。同时,毒物兴奋效应理论也为生物体代谢及平衡的波动范围,机体的抗应激能力,细胞的适应性和存活率提供了更为广泛合理的科学解释。换言之,毒物兴奋效应减少了某些环境伤害时“人仆平衡态区域”的压缩,而这种平衡态区域的压缩就是引起衰老、疾病甚至死亡的最基本原因。因此,健康老龄化也许可以通过这种温和的周期性毒物兴奋效应刺激来实现。     

应用PCR—RFLP检测胃癌组织中17p^13.3杂合性丢失

应用ＰＣＲ－ＲＦＬＰ检测胃癌组织中１７ｐ１３．３杂合性丢失王东旭房殿春罗元辉刘为纹近来研究表明，染色体特定部位的丢失与某些人类肿瘤的发生密切相关。１７号染色体短臂上一区三带三亚带（１７ｐ１３．３）就是一个常见丢失区域，这个区域可能存在一个待定的抑癌基...     

问题解答:

一、何谓过早复极综合征?有何临床意义? 答:过早复极综合征(Early repolarization Syndrome)是心电图的一种正常变异。在健康人中占1～2.5％,在黑人中更多见。原因是在心室全部去极化结束之前,某些区域的心室肌提早复极,产生向前、下偏左的ST     

心室晚电位

心室晚电位(Ventricular late poten-tials)是与心室某些病变区域存在的缓慢传导有关而延迟除极所出现的舒张期碎裂电活动,因这种晚电位(LPs)通常晚于 QRS 波而出现在 QRS 终了处并延伸至ST 段内,故得名。目前认为 LPs 是预测、预报严重室性心律失常和心脏性猝死的信号。     

大面积脑梗死的CT诊断回顾性分析

目的探讨并分析临床上CT诊断大面积脑梗死的临床征象。方法对2005年7月—2011年8月在我院就诊的80例大面积脑梗死患者的临床资料进行回顾性分析,并对其特征表现进行探讨和分析。结果 80例患者接受CT检查之后,大面积脑梗死出现的部位:脑枕叶区域梗死17例(占21.25%),脑半球区域梗死22例(占27.50%),颞、顶叶区域梗死13例(占16.25%),脑基底区域梗死9例(占15.00%),额、顶叶区域梗死12例(占11.25%),顶叶、丘脑区域梗死7例(占8.75%)。80例患者中,梗死呈大片状且片状边界模糊低密度区患者9例,梗死中线结构向对侧移动患者12例,脑中动脉呈条线状高密度分布且包含钙化患者54例,梗塞分布呈双侧显示患者5例。结论大面积脑梗死与脑出血在某些症状表现上颇为类似,在临床诊断上通过CT检查可以进行有效的区分和鉴别,能够为该病的治疗提供有价值的数据和资料支持。     

Research and Evaluation of the Influence of the Construction of the Gate and the Influence of the Piston Velocity on the Distribution of Gases into the Volume of the Casting

Distribution of gasses to the cast volume and volume of pores can be maintained within the acceptable limits by means of correct setting of technological parameters of casting and by selection of suitable structure and gating system arrangement. The main idea of this paper solves the issue of suitability of die casting adjustment—i.e., change of technological parameters or change of structural solution of the gating system—with regards to inner soundness of casts produced in die casting process. Parameters which were compared included height of a gate and velocity of a piston. The melt velocity in the gate was used as a correlating factor between the gate height and piston velocity. The evaluated parameter was gas entrapment in the cast at the end of the filling phase of die casting cycle and at the same time percentage of porosity in the samples taken from the main runner. On the basis of the performed experiments it was proved that the change of technological parameters, particularly of pressing velocity of the piston, directly influences distribution of gasses to the cast volume.     

表观扩散系数值与肝细胞癌分级的相关性以及相关性与肿瘤大小关系的分析

[摘要]　目的　探讨表观扩散系数（apparent diffusion coefficient, ADC）值与肝细胞癌（hepatocellular carcinoma, HCC）组织学分级的相关性以及不同直径肿瘤的ADC值与HCC的相关性。方法?回顾性分析2017年—2020年180例病理证实为HCC的病例资料,按肿瘤直径大小分为＜2 cm、≥2 cm且＜3 cm、≥3 cm且＜5 cm、≥5 cm 4组,标为I、II、III、IV组。分析ADC值与HCC组织学分级的相关性,并分析在不同直径肿瘤ADC值与HCC的相关性。结果?高、中和低分化HCC的ADC值分别为（1.159±0.302）×10-3、（0.951±0.213）×10-3和（0.811±0.239）×10-3 mm2/s,逐级降低（P＜0.05）。ADC值与总体HCC的组织学分级呈负相关（r=-0.474）,与I～III组HCC的组织学分级均呈负相关（r值分别为-0.663、-0.527、-0.364）,而与IV组HCC的组织学分级无相关性。结论?ADC值可以作为非侵入性预测HCC组织学分级的指标,预测结果受肿瘤大小影响,更适用于小肝细胞癌。     

缺锌对孕鼠生长发育及其肝脏、胎盘中谷胱甘肽过氧化物酶及过氧化氢酶活性的影响

为观察喂养缺锌饲料对孕鼠生长发育及其肝脏、胎盘中谷胱甘肽过氧化物酶(GSH-PX)及过氧化氢酶(CAT)活性的影响。将16只受孕Wistar鼠随机分为缺锌组(ZD组)、加锌组(ZS组)和正常对照组(ZC组),分别喂饲缺锌饲料、加锌饲料和基础饲料,记录每只孕鼠每日体重变化。于妊娠21日将孕鼠处死,取其肝脏、胎盘作GSH-PX和CAT活性测定。结果为ZD组孕鼠体重未见增加,SC组和ZS组孕鼠体重增加明显;与ZC组和ZS组相比,ZD组孕鼠肝脏和胎盘中GSH-PX活性显著降低(P<0.05),孕鼠肝脏和胎盘中CAT活性显著升高(P<0.05)。故认为缺锌可影响孕鼠肝脏、胎盘中谷胱甘肽过氧化物酶及过氧化氢酶活性,并影响其生长发育。     

Ligaments of the larynx and the adjacent pharynx and esophagus

Two ligament systems of the larynx are demonstrated by dissection. The suspensory ligament of the esophagus is attached to the posterior aspect of the cricoid cartilage and is also a part of the fascial sheath which is common to the hyoid, thyroid, and cricoid. The ligaments at the inner margins of the vocal, ventricular, and aryepiglottic folds are distinctive in site and, inferentially, in function. The aryepiglottic ligaments join at the incisura between the arytenoid cartilages and are continued as the corniculopharyngeal ligament which splays into the flexible tissues in the anterior wall of the hypopharynx, posterior to the suspensory ligament of the esophagus. These ligament systems are involved in two different actions in swallow. The gross superior and anterior motions of the larynx are transmitted to the esophagus by the suspensory ligament, so that the esophagus is elevated in relation to the bolus and is also opened. These esophageal displacements resemble, in effect, the swallow displacements of the pharyngoesophageal segment and of the constrictor wall of the hypopharynx. The marginal ligaments of the laryngeal folds help to implement the constriction and closure of the larynx during swallow. By anatomical inference, the corniculopharyngeal ligament effects vertical traction within the flexible tissues of the anterior wall of the hypopharynx.     

Humanism and the suffering of the people

Abstract
Humanism includes, among its many contexts, the ideal of the universal perfection of health. Procedures for alleviation of disease existed through all epochs of human history, but efficacy was mostly lacking. The prototypic humanism of the Renaissance ( ad  1300−1600) scarcely involved the medical ­sciences other than human anatomy. The Enlightenment of the seventeenth century included discovery of the circulation of the blood, and applications of microscopy. Discoveries relevant to medical practice began in the nineteenth century, ushered in by vaccination and the germ theory of disease. This 200-year period saw a transformation of human health according to the surrogate marker of increased life-­expectancy. This has been variously attributed to: (i) increased prosperity following the industrial revolution, (ii) efforts of humanistic social and public health reformers and, more recently, (iii) advances in medical science. Yet the beneficiaries remain a minority of the world's population. The nexus between poverty, illness and low life-expectancy between and within nations is the major challenge for the future. Contemporary science is providing ever-expanding knowledge on means to achieve the goal of perfection of human health, but the need for humanism is as great as at any previous age. Fortunately, however, the targets are more clearly visible than during the periods of poverty, plagues and pestilence of the past. (Intern Med J 2003; 33: 195−202)