烧伤后红细胞损伤的机制——过氧化脂质、维生素E与溶血的关系

本实验发现大鼠体表面积20％Ⅲ°烧伤后,皮肤内产生了大量丙二醛(MDA),第二天达最高,第七天有第二高峰,血浆和红细胞(RBC)MDA第三天达最高,血浆和RBC维生素E(VE)于伤后第二天后迅速下降,RBC溶血第三天最甚。对皮肤MDA、血浆MDA、RBCMDA、血浆VE、BBC VE、1％H_2O_2溶血进行相关分析后发现在不同时相,有不同的相关关系,但基本遵循烧伤皮肤MDA增加、血浆MDA增加、RBC MDA增加、血浆和RBC VE降低,溶血增加的规律。文中讨论了RBC损伤的机制。     

病毒性心肌炎心肌线粒体结构功能变化及大剂量维生素C干预作用

目的：探讨病毒性心肌炎（ＶＭＣ）小鼠心肌线粒体结构和功能，并用大剂量维生素Ｃ进行干预。方法：雄性Ｂａｌｂ／ｃ小鼠随机分为柯萨奇Ｂ３病毒（ＣＶＢ３）感染组（ＩＧ）、ＣＶＢ３感染加大剂量维生素Ｃ治疗组（ＩＶＧ）和对照组（ＣＧ）。采用电镜和形态计量学方法观察心肌线粒体形态、数量和膜磷脂定位，用酶细胞化学法分析心肌线粒体细胞色素氧化酶（ＣＣＯ）和琥珀酸脱氢酶（ＳＤＨ）活性。结果：ＩＧ小鼠心肌线粒体大量破坏，ＣＣＯ和ＳＤＨ活性降低，膜磷脂严重缺失、定位改变（Ｐ　＜０．０５～　０．０１）。不同时相点ＩＶＧ上述各项指标均较ＩＧ显著改善（Ｐ　＜０．０５～０．０１）。结论：ＶＭＣ心肌线粒体结构严重破坏、功能明显下降，大剂量维生素Ｃ能有效保护心肌线粒体结构和功能。     

Proteolytic Processing Mechanisms in the Biosynthesis of Neuroendocrine Peptides: The Subtilisin-like Proprotein Convertases

The recent discovery of a novel family of precursor processing endoproteases has greatly accelerated progress in understanding the complex mechanisms underlying the maturation of prohormones, neuropeptides, and many other precursor-derived proteins. At least six members of this family have been found thus far in mammalian species, several having alternatively spliced isoforms, and related enzymes have been identified in many invertebrates, including molluscs, insects, nematodes, and coelenterates. The proprotein convertases are all dependent on calcium for activity and all possess highly conserved subtilisin-like domains with the characteristic catalytic triad of this serine protease (ordered Asp, His, and Ser along the polypeptide chain). Two members of this family, PC2(SPC2) and PC1/PC3(SPC3), appear to play a preeminent role in neuroendocrine precursor processing. Both convertases are expressed only in the brain and in the extended neuroendocrine system, while another important family member—furin/PACE (SPC1)—is expressed more ubiquitously, in almost all tissues, and at high levels in liver. SPC2 and SPC3 exhibit acidic pH optima and other properties which enhance their activity in the acidic, calcium-enriched environment of the dense-core secretory granules of the regulated pathway in neuroendocrine cells, while furin has a neutral pH optimum and is localized predominantly to the trans Golgi network where it is retained by a C-terminal transmembrane domain. Furin processes a wide variety of precursors in the constitutive pathway, such as those of growth factors, receptors, coagulation factors, and viral glycoproteins. Recent findings on the processing of proopiomelanocortin, proinsulin, proglucagon, and several other neuroendocrine precursors by SPC2 and SPC3 are discussed, along with information on the structure, properties, evolution, developmental expression, and regulation or the convertases. An inherited defect in the fat/fat mouse which affects the processing of proinsulin, and probably also many other prohormones, due to a point mutation in carboxypeptidase E has recently been identified and has begun to provide new insights into the functional integration of the individual processing steps.     

双波长分光光度法测定复方甲硝唑片含量

本文采用双波长分光光度法测定复方甲硝唑片含量，可不经分离直接测定甲硝唑和维生素Ｂ６；其平均回收率分别为：１０２．５２％（ＲＳＤ＝１．２１％ｎ＝５），９９．２７％（ＲＳＤ＝２．５６％ｎ＝５）。     

食管癌患者与对照组血清维生素A水平分析

目的:为了解食管癌患者和非食管癌患者体内维生素A的水平及其与食管癌发病的关系.方法:采用微量荧光法对32例食管癌患者(实验组)和32例非食管癌患者(对照组)血清中维生素A含量进行了测定.结果:显示实验组与对照组血清维生素A均值分别为1.55μmol/L,1.69μmol/L.经统计学处理两组血清维生素A水平有显著性差异(P<0.01).结论:提示食管癌的发生可能与机体维生素A水平有关,这种关系需进一步探讨.     

Conditions of Alzheimer-type dementia in the old-old and oldest-old patients with special reference to extreme conditions of brain aging

A neuropathological study on 1540 consecutive autopsy brains ranging from 60 to 107 years of age revealed the following points. (1) Of the of the demented cases of the plaque-predominant type, 93% were complicated with multiple tiny cortical infarcts. They showed a tendency for dementia to develop before or after the appearance or worsening of a systemic disorder such as cardiovascular disease, respiratory infection and cancer. However, there was no case showing Alzheimer-type dementia (ATD). (2) The plaque-predominant type might be an extreme condition of brain aging in terms of senile plaques (SP). It is likely that although the pathological appearance of SP alone is not responsible for dementia, its coexistence with multiple cortical infarcts could be the cause of dementia. Therefore, this type should be distinguished from ATD. (3) Primary hippocampal degeneration could also be an extreme condition of brain aging in terms of neurofibrillary tangles. This condition was different pathologically from the hippocampal lesion in ATD. (4) Several characteristics of old-old and oldest-old patients were clarified.     

维生素E对培养心肌细胞脂质过氧化损伤的保护

应用氢过氧化枯烯引发体外培养的乳鼠心肌细胞脂质过氧化损伤过程，观察了添加维生素Ｅ（２００ｍｇ／Ｌ的α－生育酚）的影响。结果显示：维生素Ｅ能明显减轻细胞脂质过氧化物的蓄积、细胞内肌酸激酶漏出和ＤＮＡ断裂，保护细胞膜流动性、肌球蛋白轻链肌酸激酶和头部ＡＴＰ酶的活性；但对￣３Ｈ－ＴｄＲ掺入的影响不显著。表明维生素Ｅ具有抵抗脂质过氧化所致心肌细胞损伤的作用。     

房室间隔缺损的形态学诊断——二维超声心动图与心血管造影,手术的比较

为了评估二维超声心动图（２ＤＥ）对房室间隔缺损（ＡＶＳＤ）的诊断和手术方法选择价值，对８７例ＡＶＳＤ的２ＤＥ，心血管造影及手术结果进行回顾对照研究，病例年龄自３月至１１月（平均３．９岁）。部分型ＡＶＳＤ４６例，过渡型１２例，完全型２９例（Ａ型２１例，Ｂ型４例，Ｃ型４例）２ＤＥ诊断与手术诊断符合率在部分型ＡＶＳＤ中为９７％，在过渡型及完全型ＡＶＳＤ中为８４％，２ＤＥ诊断与手术诊断不符合大多为过渡型与     

Significance of antibodies to the recombinant E2 protein of hepatitis G virus in haemodialysis patients

Patients on maintenance haemodialysis represent a high-risk group for parenterally transmitted viral infections, such as hepatitis B, C and G. In addition to hepatitis G virus (HGV) (GBV-C) RNA, analysed in previous studies, we characterized the seroprevalence rates of antibodies to the putative E2 protein (anti-E2) of HGV in a German cohort of patients on maintenance dialysis ( n = 72) in comparison to healthy blood donors ( n = 100). The presence of anti-E2 and/or HGV RNA as indicators of present or past HGV infection could be demonstrated in 34.7% of patients and in 16% of the blood donors ( P < 0.01). The infection rates with HGV seem to increase only during the first 6 years of haemodialysis. The simultaneous presence of viraemia and anti-E2 was found very rarely in patients and controls. Therefore, the emergence of anti-E2 indicates clearance of HGV viraemia. In conclusion, patients on haemodialysis are at high risk of acquiring HGV infection, but a chronic carrier state with viraemia is rare. The risk of infection is not strictly correlated with the duration of dialysis.     

The hemolysin of escherichia coli

Many strains of E. coli elaborate a hemolysin which is responsible for the zone of -hemolysis surrounding bacterial colonies on blood agar. The significance of this cytolysin as a determinant of bacterial pathogenicity has been established in animal models with the use of genetically engineered, isogenic bacterial strains. An analogous role in human infections has been inferred from the high association of hemolysin production with disease. Studies at a molecular genetical level have defined 4 genes that are required for the synthesis, post,translational modification and secretion of the hemolysin. The structural gene hlyA encodes for a 107-110 000 polypeptide, which must be modified in an unknown manner to its active form by the product of the neighboring hlyC gene. Genes hlyb and hlyD encode for proteins that export the molecule to the extracellular medium. The signal for secretion is contained in the C-terminal portion of the toxin molecule. The secreted hemolysin attacks plasma membranes of target mammalian cells by inserting as a monomer into the bilayer and generating hydrophilic transmembrane pores of approximately 2 nm effective diameter. The pores display a marked selectivity for cations over anions and pore-opening is dependent on the presence of a correct transmembrane potential. Binding to a membrane target does not require the presence of a specific receptor, and pores may be generated in planar lipid membranes consisting solely of phosphatidylcholine. Pore formation in nucleated cells can trigger secondary reactions such as stimulation of arachidonate metabolism with release of lipid mediators, probably initiated by passive influx of extracellular Ca²⁺. Perfusion of subcytolytic doses through isolated and ventilated rabbit lungs induces lung edema that is at least partially due to such secondary events. The capacity of E. coli hemolysin to damage human tissues via primary and secondary processes is consistent with the concept of its pathogenic role in human infections.[/p]Corresponding author.