4-氨基吡啶对皮层神经元细胞内游离钙的影响

目的研究4-氨基吡啶(4-AP)对体外培养的皮层神经元细胞内游离钙浓度([Ca2+]i)的影响,了解4-AP的药理学作用机制.方法荧光探针Fluo-3-AM标记体外培养的皮层神经细胞内游离钙后,用共聚焦显微镜观察记录4-AP及L型谷氨酸对小鼠原代培养的皮层神经元[Ca2+]i的影响.结果4-AP与谷氨酸均能提高[Ca2+]i,两者峰值与持续时间存在差异,共同作用于细胞时的上升曲线与单用谷氨酸时相仿.结论4-AP的药理作用机制可能与提高神经细胞[Ca2+]i有关,其中机制与兴奋性氨基酸的[Ca2+]i升高作用可能不同.     

大电导钾通道对小鼠皮层神经元胞内游离钙和动作电位的影响

目的 探讨大电导钾通道（BK）对小鼠大脑皮层神经元胞内游离钙 ( [Ca2+]i） 和兴奋性的调节作用。方法 体外培养小鼠皮层神经元,用膜片钳技术观察BK特异性阻断剂IBERIOTOXIN对神经元 [Ca2+]i和动作电位频率的影响,用显微荧光测钙法观察IBERIOTOXIN对高钾条件下[Ca2+]i的影响。结果 生理状态下,IBERIOTOXIN灌流(100nmmol/L)对神经元细胞自发动作电位的频率、[Ca2+]i无显著影响;持续电刺激去极化后,IBERIOTOXIN灌流使动作电位频率增加,[Ca2+]i显著升高。高钾溶液(20mmol/L)引起神经元[Ca2+]i升高, 而IBERIOTOXIN灌流则使[Ca2+]i进一步显著升高。结论 BK对小鼠受持续去极化刺激或高钾条件时的神经元[Ca2+]i和兴奋性具有明显调节作用。     

急性给予ApoE4升高大鼠皮层神经元内静息[Ca~(2+)]i

目的研究载脂蛋白E(ApoE)对大鼠皮层神经元内游离钙离子水平[Ca2+]i的影响。方法用激光共聚焦显微镜(LSCM)和Fluo-3/AM荧光探针标记检测皮层神经元钙信号瞬间动态变化;用N-甲基-D-天冬氨酸(NMDA)受体阻断剂MK-801观察ApoE4对其影响。结果ApoE4可以呈时间及浓度依赖性升高神经元内静息[Ca2+]i(P<0.01或P<0.05),MK-801可以部分阻断ApoE4所致的静息[Ca2+]i升高(P<0.05或P<0.01);而ApoE3无影响。结论急性给予ApoE4能升高神经元内静息[Ca2+]i,NMDA受体的激活可能参与了ApoE4所致的胞内钙信号改变与其神经毒作用。     

外源性锌对缺氧神经元的保护作用

目的:观察不同浓度外源性锌对神经元细胞内游离钙([Ca2 ]i)的影响,探讨低浓度外源性锌对于缺氧神经元保护作用的可能机制.方法:原代培养大鼠皮层神经元,加入不同浓度的外源性锌,激光扫描共聚焦显微镜检测神经元[Ca2 ]i的变化;建立细胞缺氧模型,检测10 μmol/L外源性锌对于缺氧神经元[Ca2 ]i和[Zn2 ]i的影响.结果:神经元的[Ca2 ]i,μmol/L锌组与对照相比无明显变化;100μmol/L锌组一过性升高,后降至对照水平;500 μmol/L锌组,明显高于对照水平.除正常加锌组外,其余各组神经元[Zn2 ]i和[Ca2 ]i均较正常对照组增高;但正常加锌组、缺氧加锌组神经元[Zn2 ]i和[Ca2 ]i均较缺氧组降低.结论:外源性锌对于神经元的作用随浓度而不同;10 μmol/L外源性锌维持了神经元的钙稳态,它对于缺氧神经元的保护作用,可能通过抑制钙超载实现.     

皮质酮快速升高大鼠脊髓背角神经元钙浓度

目的:观察皮质酮(CORT)对培养的脊髓背角神经元Ca2+浓度([Ca2+]i)的调节作用及机制。方法:培养新生SD大鼠脊髓背角神经元,激光共聚焦显微镜检测神经元[Ca2+]i的变化。结果:CORT可快速升高培养的脊髓背角神经元[Ca2+]i,且呈现剂量依赖性(P0.05);CORT诱导的神经元[Ca2+]i升高是以外钙内流为主(P0.01);百日咳毒素(G蛋白活化阻断剂)可阻断CORT所致的脊髓背角神经元[Ca2+]i升高(P0.01),而糖皮质激素受体拮抗剂RU38486对CORT的效应无抑制作用。结论:CORT通过非基因组途径快速增高培养的脊髓背角神经元[Ca2+]i。     

尾加压素Ⅱ对大鼠肾小球系膜细胞内游离钙浓度影响

目的探讨尾加压素Ⅱ(UrotensinⅡ,UⅡ)对肾小球系膜细胞(GMC)内游离钙浓度的影响及其作用机制.方法以体外培养的SD乳鼠GMC为研究对象,用UⅡ刺激GMC,Fluo3/AM荧光标记细胞内游离钙离子,激光共聚焦显微技术动态测定GMC内游离钙浓度变化.结果UⅡ激发GMC内[Ca2+]i升高作用分2个时相,即瞬时峰值升高时相和缓慢持久升高时相,对峰值升高呈剂量依赖方式,在10-10mol/L～10-7mol/L范围内引起峰值升高,且随着剂量增加,幅度增大.硝苯地平和无钙缓冲液对UⅡ激发GMC内[Ca2+]i瞬时峰值升高无作用,但可完全阻止缓慢持久升高时相出现.结论UⅡ激发GMC内[Ca2+]i浓度瞬时峰值升高时相是由细胞内储存钙释放介导的,而缓慢持久升高时相是由细胞外钙流入增加引起的.     

阿司匹林对化学性缺氧状态下新生大鼠脑神经细胞[Ca~(2+)]i和NGB的影响

目的 探讨阿司匹林(ASA)对化学性缺氧大鼠脑神经细胞的保护作用及细胞外钙离子对ASA神经保护作用的影响。方法 分别在含钙和去钙培养液中加入连二亚硫酸钠（Na2S2O4）诱导化学性缺氧,用ASA预处理体外培养的大鼠脑细胞,激光共聚焦显微镜观察[Ca2+]i和脑红蛋白（NGB）的变化。结果 化学性缺氧使大鼠脑细胞[Ca2+]i和NGB表达增高（P＜0.05, n=5）。ASA预处理可明显缓解缺氧组和无钙缺氧组大鼠脑细胞[Ca2+]i和NGB的增高（P＜0.05, n=5）。结论 ASA可能通过减少大鼠脑细胞的钙超载,抑制缺氧诱导的NGB表达增高,发挥神经细胞保护作用。     

急性缺氧对大鼠远端肺静脉平滑肌细胞内钙浓度的影响

目的:研究急性缺氧对大鼠远端肺静脉平滑肌细胞(PVSMC)细胞内钙浓度([Ca2+]i)的影响及L型电压依赖性钙通道(VDCC)阻断剂硝苯地平的作用,为缺氧性肺动脉高压发病机制的进一步研究提供理论依据.方法:胶原酶消化法培养大鼠远端PVSMC,利用荧光显微镜和细胞内钙浓度检测系统观测急性缺氧(4％O2)、高钾(60 mmol/L KCl)溶液对PVSMC的[Ca2+]i影响及硝苯地平的干预作用.结果:对照组PVSMC的[Ca2+]i随时间变化维持基线水平;缺氧组PVSMC急性缺氧后,[Ca2+]i迅速升高并维持平台水平,△[Ca2+]i达82.83 nmol/L士23.03 nmol/L;硝苯地平干预组PVSMC予急性缺氧和5μmol/L硝苯地平干预后,[Ca2+]i升高幅度较小;高钾溶液孵育PVSMC后,[Ca2+]i迅速增高,5 μmol/L硝苯地平能完全阻断PVSMC的[Ca2+]i对高钾溶液的反应.结论:急性缺氧可使大鼠远端PVSMC的[Ca2+]i升高,其机制可能与激活PVSMC的VDCC和另外的非VDCC依赖的钙通道导致细胞外Ca2+内流有关.     

长春新碱诱导的自噬性凋亡与细胞内游离Ca~(2+)浓度的相关性研究

目的　研究长春新碱 (VCR)诱导的L 0 2细胞自噬性凋亡时细胞内游离钙离子浓度 ([Ca2 +]i)的变化 ,以及自噬特异性抑制剂 3 methyladenine(3MA)对此自噬性凋亡和 [Ca2 +]i的影响。方法　应用已建立的VCR诱导L 0 2细胞自噬性凋亡模型 ,使用电镜、流式细胞术检测细胞凋亡 ;用Fluo 3/AM荧光探针经流式细胞仪测定L 0 2细胞平均 [Ca2 +]i。结果　电镜及流式细胞术检测证实VCR诱导L 0 2细胞发生了自噬性凋亡 ,此凋亡过程中 [Ca2 +]i明显升高 ,以凋亡早期更为明显 :3MA可显著抑制VCR所致的 [Ca2 +]i升高并能降低凋亡细胞比例。结论　在体外条件下VCR可以诱导L 0 2细胞自噬性凋亡 ,其发生可能与VCR导致 [Ca2 +]i升高有关 ;3MA可能通过抑制 [Ca2 +]i升高而抑制自噬及VCR所致的自噬性凋亡。     

皮质酮对原代培养的海马神经元及其Ca2+/CaMKⅡ的影响

在培养液中加入10-7、10-6和10-5浓度(mol/L)的皮质酮,采用MTT染色测定、Fura-2/AM的荧光标记以及Western印迹的方法,观察了不同浓度的皮质酮作用下海马神经元形态学和细胞存活率的变化以及胞浆内游离钙离子浓度[Ca2+]i和CaMKII表达的变化规律,探讨其对原代培养的大鼠海马神经元及其Ca2+/CaMKII的影响和可能的机制.结果发现10-6、10-5浓度的皮质酮对海马神经元的形态学影响较大,与对照组比较,细胞存活率明显降低;[Ca2+]i分别为113.1022±16.9716、155.3794±20.7727;CaMKII的表达也明显减少;三者的变化均显著(P＜0.01),而10-7浓度的皮质酮对上述指标影响不大(P＞0.05).此外,相关性分析表明[Ca2+]i和CaMKII的表达呈现负相关(P＜0.05).以上结果提示,皮质酮对大鼠海马神经元的作用存在浓度依赖效应,浓度越高,对大鼠海马神经元的损伤越大,同时也验证了皮质酮是啮齿类动物的主要的应激激素.     

Secular change in menarche in women in Madrid

The age at menarche was estimated by recollection in 1617 women between the ages of 18 and 60 in Madrid and a nearby suburb, Pinto. The population of Pinto is working-class and the Madrid group, taken from residential neighbourhoods , belongs to the upper middle class. In both groups we found a diminution in average age at menarche, from 14.04 to 13.02 years in Madrid and from 14.55 to 13.16 years from about 1935 to about 1965 in Pinto. These changes have been more intense in the group which is less well-off economically, where living conditions have varied much more drastically.     

Intestinal helminthiasis in school children in Haiti in 2002

A survey on intestinal helminths in school children was conducted in Haiti in 2002. This first nationwide study involving the entire country was stratified by department according to urban and rural zones using the cluster method. Focusing on elementary school children (n=5792; age range 3 to 20 years), it involved 26 urban and 49 rural schools randomly selected. Stools were preserved in formalin and examined by the Ritchie technique. Thirty-four per cent of stools (1981/5792) tested positive for intestinal helminths with the following parasites identified: Ascaris lumbricoides (27.3%), Trichuris trichiura (7.3%), Necator americanus (3.8%), Hymenolepsis nana (2%), Taenia sp. (0.3%) and Strongyloides stercoralis (0.2%). The helminth prevalence was higher in rural (38.4%) compared to urban areas (30%). There was no significant difference in prevalence by sex and age. The importance of geohelminths changed from one department to another with the highest prevalence found in the Southern department of Grande Anse (73.7%) and the lowest prevalence in the Center department (20.6%). Five out of the country's nine departments had a similar prevalence varying from 25.5% to 28.2%. Intestinal helminthic polyparasitism was observed in a percentage of infested school children comprise between 3.4% and 28.6% according in relation to the geographical area. A program to fight against geohelminths in school children should be initiated as a public health priority. Albendazole is the drug of choice. Frequency of drug distribution should be based on the prevalence of geohelminths in each department.     

Experience in adult population in dengue outbreak in Delhi

A dengue outbreak has recently hit the Indian capital. We studied the clinical profile of adult patients. Five hundred and sixty patients of dengue infection were admitted in a specially created ward according to the criteria laid down by WHO. Haematemesis (28.28%), epistaxis (26.78%) and malena (14.28%) were some of the common presentations. Similarly lymphadenopathy, especially cervical (30.89%), palatal rashes (26.96%) and hepatomegaly (23.75%) were the most commonly encountered findings on physical examination. Most of the cases were of dengue fever with haemorrhage and only 2.5% cases were classified under dengue haemorrhagic fever or dengue shock syndrome. The average hospital stay was 3.4 days but only 9.8 hours in the eleven patients who died, suggesting their late arrival in preterminal situation giving little time for resuscitation. Thrombocytopenia was not a feature and only 12.85% patients had platelet count less than 70,000/cmm. Most of the patients who were admitted with thrombocytopenia, showed normalization in their platelet counts in next few days. Serological examination demonstrated evidence of recent dengue infection in 41.17% patients. Few patients required blood or platelet concentrate transfusion. Eleven patients died, three due to DIC, one of intracranial haemorrhage and seven due to massive gastric haemorrhage. Rest of the patients recovered completely. Thus we can conclude that recent outbreak in Delhi was of dengue fever with haemorrhage and mortality was very low in patients who came early to the hospital.     

Changes in the hypothalamic nuclei in in experimental allergy

Summary In rabbits subjected to prolonged sensitization and in which the Arthus phenomenon was induced there was a marked reaction of the hypothalamic nuclei. Staining by Gomori's method indicated a cellular swelling, loss of granules, and protoplasmic vacuolization in the supraoptic nucleus. There was a considerable increase in the size of the cross-sectional area of the cells. The same effects were much less well shown in the paraventricular nucleus. These results show that marked signs of increased neurosecretion developed in the animals at the height of the Arthus phenomenon.(Presented by Active Member AMN SSSR V. V. Parin) Translated from Byulleten Éksperimental'noi biologii i Meditsiny, Vol. 55, No. 4, pp. 110–113, April, 1963.     

Development in in vitro toxicology

There are three principal pressures driving the development of in vitro toxicology: (1) the need for more efficient testing systems to cope with the large number of xenobiotics currently being developed; (2) public pressure to reduce animal experimentation; and (3) a need for a better understanding of the mechanisms of toxicity. Within this, in vitro toxicology is focused on local, systemic, and target-organ toxicity. It is becoming increasingly apparent that a step or decision-tree approach using input of a variety of experimental data (physicochemical properties, biokinetics, cytotoxicity) provides the most efficient system for predicting toxicity. Examples of the use of in vitro toxicity systems for prediction of systemic toxicity and target-organ (liver) toxicity are presented.Originally presented at ECCP 93.