Modification of DiFrancesco-Noble equations to simulate the effects of vagal stimulation onin vivo mammalian sinoatrial node electrical activity

We present a new mathematical model for vagal control of rabbit sinoatrial (SA) node electrical activity based on the DiFrancesco-Noble equations. The original equations were found to be unstable, resulting in progressive cycle by cycle depletion or accumulation of ions in intra- and extracellular compartments. This problem was overcome by modifying the maximum Na−K pump current and the time constant for uptake of intracellular calcium. We also included a formulation for the acetylcholine (ACh)-activated potassium current which was consistent with experimental data. This formulation was based on kinetics first proposed by Osterrieder and later modified by Yanagihara. The resulting model exhibits cycle-cycle ionic stability, and includes an ACh-activated potassium current which accurately reproduces experimentally observed effects of vagal stimulation on both the membrane potential and its timederivative. Simulations were performed for both brief-burst and prolonged vagal stimulation using simplified square wave profiles for the concentration of ACh in the synaptic cleft space. This protocol permits the isolation of cardiac period dynamics caused by changes in membrane potential and intra- and extracellular ionic concentrations from those caused by other mechanisms including the dynamics of ACh release, diffusion, hydrolysis and washout. Simulation results for the effects of brief-burst single cycle stimulation on the cardiac period agree closely with experimental data reported in the literature, accurately reproducing changes in membrane potential and the phasic dependency of the response to the position of vagal stimulus bursts within the cycle. Simulation of the effects of prolonged vagal stimulation accurately reproduced the steady-state characteristics of heart period response, but did not yield the complex multimodal dynamics of the recovery phase, or the pronounced post vagal tachycardia observed experimentally at the termination of the stimulus. Our results show that the major chronotropic effects of vagal stimulation on the SA cell membrane can be explained in terms of the ACh-activated potassium current. The effects of this membrane current however are generally fast acting and cannot contribute to any long lasting dynamics of the cardiac period response. The modified DiFrancesco-Noble model presented in this article provides a valuable theoretical tool for further analysis of the dynamics of vagal control of the cardiac pacemaker.     

流行性乙型脑炎病毒活疫苗株SA14-14-2基因稳定性研究

目的 通过研究流行性乙型脑炎活疫苗减毒株基因稳定性，从分子水平证实流行性乙型脑炎活疫苗的遗传稳定性。方法分析流行性乙型脑炎活疫苗主种子、工作种子及其相应的疫苗病毒E蛋白基因核苷酸和氨基酸序列，并与其强毒株和基因库中乙脑病毒减毒株(AF15119)比较。结果乙脑活疫苗主种子、工作种子及其相应的疫苗病毒的E蛋白基因核苷酸序列完全相同。这些病毒E蛋白的氨基酸序列与基因库中乙脑病毒弱毒株(AF315119)比较显示第E447位点氨基酸有差异。结论乙脑病毒活疫苗减毒株遗传学特性稳定。     

胃癌患者8种肿瘤标志物测定的临床价值

对 30 2例胃癌术前检测CA5 0、CA199、CA12 5、CA72 4、CEA、β2 -MG、SA、Fer等 8种肿瘤标志物 ,并按年龄、胃癌病期及病理分类分组分析。结果 :(1) 30 2例胃癌血清中 8种肿瘤标志物总的阳性率依次为 β2 -MG6 5 .9%、CA19932 .1%、CA72 42 9.5 %、SA2 4.5 %、CA12 5 16 .9%、CEA13 .2 %、CA5 0 11.6 %、Fer(- )。 (2 ) 8种肿瘤标志物阳性率与年龄大小均无关。 (3) β2 -MG、CA72 4、CA12 5、CA199、SA、CEA、在Ⅲ、Ⅳ期病例中均较敏感 ,且随病期增加 ,阳性率增高。 (4 )CA199和CA72 4对腺癌、β2 -MG和SA对低分化腺癌、β2 -MG和CA72 4对粘液癌、混合型癌阳性率较高。提示血清测β2 -MG、CA199、CA72 4、SA、CA12 5对胃癌的辅助诊断有一定应用价值     

流行性乙型脑炎减毒活疫苗大面积接种后安全性和流行病学效果的5年观察

目的 考核乙脑减毒活疫苗大面积接种后的安全性和降低乙脑发病率,在乙脑高发区安徽省蒙城和涡阳县进行为期５年（１９９２￣１９９６年）的人群观察。方法 观察对象１￣６岁儿童。１岁初免１针,２岁加强１针。结果 通过５年连续观察共接种乙脑活疫苗３３５９４１人。 表明：①疫苗对小龄儿童接种后近期和５年内均未出现不良反应,表明疫苗是安全的。②当地乙脑平均总发病率有显著性下降,从接种观察前１９８７￣１９９１年的１     

食管癌患者手术切除前后SA、CEA和SCP检测的临床意义

目的　探讨食管癌患者手术切除前后血清 SA、CEA、SCP水平的变化。方法　应用放免法测定 4 3例食管癌患者血清 CEA含量 ,化学法测定 SA和 SCP含量 ,并以 35名正常健康人作对照。结果　食管癌患者在手术切除前血清 SA、CEA、SCP水平非常显著地高于正常人组 (P<0 .0 1) ,手术切除后 6个月转移者血清 SA、CEA、SCP水平持续异常 ,未转移者血清 SA、CEA、SCP在正常水平。结论　血清 SA、CEA、SCP含量测定的变化与食管癌患者的病情和预后密切相关 ,有一定的临床应用价值     

血清SA,Cu／Zn比值联合检测诊断肺癌患者的临床意义

对１７８例原发性肺癌患者血清唾液酸（ＳＡ）含量、铜／锌（Ｃｕ／Ｚｎ）比值进行了测定分析，并与８０例正常人作对照。结果表明：原发性肺癌患者血清ＳＡ含量（１２２．２０±３６．３０）、Ｃｕ／Ｚｎ比值显著高于对照组，（Ｐ＜０．０１）。单项检测：两项指标对肺癌的诊断敏感性分别为７６．４％和６１．２％，特异性为９７．５％和７６．３％；联合检测：以两项之一阳性为诊断依据时，特异性可达９８．７％。表明ＳＡ和Ｃｕ／Ｚｎ比值联合检测较单项检测对肺癌的诊断更有临床应用价值。     

苦参碱对人增生性瘢痕成纤维细胞增殖的体外抑制作用

组织损伤修复是人体自我保护的一个正常病理过程,而过度修复则会出现组织纤维化,影响组织、器官的正常功能,人增生性瘢痕是创伤过度修复的异常结果。苦参碱(matrine,Mat)广泛存在于豆科植物苦参、苦豆子及广豆根中,近年研究发现其具有较强的抗组织纤维化作用[1],目前关于Mat对人增生性瘢痕成纤维细胞(下文简称为成纤维细胞)作用的报道较少。本实验以成纤维细胞为靶细胞观察不同质量浓度的Mat在体外对该细胞增殖的影响,并对其抗纤维化作用机制进行初步研究。1材料与仪器苦参碱标准品(中国药品生物制品检定所提供);DMEM培养基(Gibco公司产…     

三种方法检测乙型肝炎病毒表面抗原阳性结果的分析

目的探讨微粒子化学发光检测技术(MEIA),酶联免疫吸附试验(ELISA)和胶体金免疫层析试验(GICA)检测乙型肝炎病毒表面抗原(HBs Ag)的结果符合率。方法用MEIA、ELISA和GICA三种方法对200份标本进行乙型肝炎病毒表面抗原检测,比较三种方法的阳性率、敏感度和特异度。结果 ELISA法阳性率为43.5%,阴性率为56.5%;GICA法阳性率为41.0%,阴性率为59.0%;MEIA法阳性率为45.5%,阴性率为54.5%。ELISA与MEIA符合度较高,阳性率较高,GICA与MEIA符合度差,阳性率最低。三种方法中以MEIA法的敏感度和特异度最高,其次为ELISA法,GICA法最低。结论 GICA灵敏度较低,只能作为初筛;ELISA较MEIA灵敏度略低,遇到检测样本吸光度值(OD值)在对照样本临界值(cut off值)附近时,需要复检。     

Renal Kallikrein-Kinin System and the Depressor Effect of Angiotensin Converting Enzyme Inhibitors MK 421, SA 446, And Captopril In Rats

Responses in urinary kallikrein and kinin excretion and systolic blood pressure to MK 421, SA 446 or captopril were studied in normotensive rats fed on a regular or a low sodium diet to assess the role of renal kallikrein-kinin system in their hypotensive effect. MK 421, SA 446 or captopril were infused at a rate of 6 mg/kg/day by osmotic minipump implanted intraperito-neally for up to 6 days. The magnitude of fall in systolic blood pressure was greater on a low sodium diet when compared to on a regular diet, whereas the pattern of the fall was similar on both diets. The magnitude of falls in plasma angiotensin II and aldosterone concentration induced by MK 421, SA 446 and captopril was not significantly different between both regular and low sodium diets. Urinary kallikrein and kinin excretion and sodium excretion were increased during infusion of MK 421, SA 446 or captopril on a low sodium diet, however any significant changes were not found in each of them on a regular diet

The present results suggest that on a low sodium diet the augmented hypotensive response to angiotensin converting enzyme inhibitors in the rats might be due to the enhanced renal kallikrein-kinin system in addition to suppressed renin-angiotensin system     

Primary Sjögren's syndrome complicated by sarcoidosis and psoriasis vulgaris

Abstract

Primary Sjögren's syndrome (SS), sarcoidosis (SA), and psoriasis vulgaris (PV) are all chronic diseases of unknown etiology. Recent studies suggest that activated T cells play a central role in their pathogenesis. We describe a case of a Japanese woman with primary SS complicated by SA and PV. To our knowledge, this is the first case in which these three diseases coexist. Although these three disorders may have a common immunopathogenic mechanism, the extreme rarity of their coexistence suggests that distinct etiological mechanisms are also involved and appear to play an important role in triggering and developing each disease.