同型半胱氨酸促进大鼠血管平滑肌细胞增殖和表型转化

目的:研究同型半胱氨酸(Hcy)对大鼠血管平滑肌细胞(VSMCs)表型转化和增殖的影响,以期为Hcy作为动脉粥样硬化(AS)独立危验因子的分子机制提供证据。方法:体外培养大鼠血管平滑肌细胞,用不同浓度的Hcy作用于细胞24h后:(1)MTT法测定细胞的增殖率;(2)流式细胞术检测细胞周期;(3)半定量RT-PCR法检测平滑肌22α(SM22α)mRNA的表达;(4)透射电镜观察VSMCs的形态学特征,确定其表型转换特征。结果:Hcy可导致细胞增殖率增加;G0/G1期细胞逐渐减少,S期细胞逐渐增多;SM22α mRNA表达下调,Hcy浓度增至1000μmol/L时差异显著;透射电镜显示,高浓度Hcy作用后VSMCs胞浆中内质网、高尔基复合体明显增多、胞核大、染色质疏松。结论:Hcy促进VSMCs增殖的同时可促进其表型的转化。     

同型半胱氨酸诱导血管平滑肌细胞组织因子表达增强

目的: 研究同型半胱氨酸（Hcy）诱导人血管平滑肌细胞（VSMCs）组织因子（TF）表达的作用，及其对核转录因子（NF-κB）活性和诱导型一氧化氮合酶（iNOS）表达的影响。 方法: 培养人脐动脉VSMCs，将不同浓度的Hcy和/或NF-κB抑制剂PDTC与VSMCs孵育不同时间，用RT-PCR方法检测TF mRNA表达，用Western blotting检测核NF-κB水平，用流式细胞术（FCM）检测细胞表面TF蛋白水平和iNOS水平。 结果: 10 μmol/L Hcy作用4 h，TF表达开始升高，500 μmol/L达峰值，Hcy能显著诱导VSMCs表达TF mRNA；对照组VSMCs细胞膜表面有低水平的TF蛋白表达，10 μmol/L Hcy作用4 h即可诱导VSMCs表达TF蛋白，500 μmol/L 达高峰，Hcy能显著诱导VSMCs表达TF；500 μmol/L Hcy作用1 h，细胞核NF-κB水平明显升高，Hcy可诱导VSMCs NF-κB活化;NF-κB抑制剂PDTC可明显抑制Hcy对TF mRNA和细胞TF表达的诱导作用；单独Hcy作用不能诱导VSMCs表达iNOS。 结论: Hcy能显著诱导VSMCs表达TF，增强VSMCs的NF-κB活化，从而介导TF基因表达和蛋白合成，通过NF-κB介导VSMCs表达TF可能是Hcy导致AS、血栓形成的重要机制。     

同型半胱氨酸对血管平滑肌细胞分泌金属蛋白酶组织抑制剂-1的影响

目的：观察同型半胱氨酸(Hcy)对血管平滑肌细胞(VSMCs)分泌金属蛋白酶组织抑制剂-1(TIMP-1)的影响。方法：体外培养大鼠VSMCs，加入不同浓度的Hcy培养48 h，应用Western blot技术观察Hcy对VSMCs分泌基质金属蛋白酶-1(MMP-1)和TIMP-1的影响，并通过半定量RT-PCR方法观察TIMP-1 mRNA表达的变化。结果：Hcy减少VSMCs MMP-1的分泌，上调TIMP-1 mRNA的表达，使TIMP-1分泌增加，并呈剂量依赖效应。结论：提示Hcy减少胶原降解可能是致动脉粥样硬化的发病机制之一。     

三七总皂甙抑制兔血管平滑肌细胞增殖及促进C-MYC基因表达

血管平滑肌细胞(vascular smooth muscle cells,VSMCs)的异常增殖与凋亡在动脉粥样硬化(atherosclerosis,AS)病理生理过程中起核心作用[1~3]。三七总皂甙(panax notoginsengsaponins,PNS)具有抗AS的作用。本研究观察PNS对VSMCs增殖周期、细胞凋亡过程及凋亡相关基因C-MYC表达的影响,探讨其作用机制。1材料与方法1·1 VSMCs的培养及分组:分离并培养兔胸主动脉VSMCs,取生长状态良好的第4~8代细胞用于实验。参照文献[3]将实验分为空白对照、300和600 mg/L PNS 3组。PNS(纯度>99%)由中国药品生物制品检定所提供。1·2细胞增殖和…     

LDLR启动子区DNA甲基化调控同型半胱氨酸致平滑肌细胞增殖的作用机制

 摘 要：目的 探讨低密度脂蛋白受体(LDLR)在同型半胱氨酸(Hcy)致血管平滑肌细胞(VSMCs)增殖中的作用机制。方法 原代培养VSMCs, 用50、100、200 、500 μmol/L Hcy干预72 h; MTT法观察VSMCs增殖的活性, ELSIA法和同位素法分别检测VSMCs中ox-LDL含量和DNA甲基转移酶活性; 实时定量PCR和巢式降落式甲基化特异性PCR(nMS-PCR)检测LDLR的表达和启动子区DNA甲基化的状态。结果 随着Hcy浓度的增加, VSMCs中ox-LDL含量和DNA甲基转移酶活性明显增加, 而VSMCs增殖活性下降, 同时LDLR mRNA表达增高, 且LDLR 基因启动子区呈低甲基化状态, 与对照组比较有显著性差异(P<0.05, P<0.01)。结论 LDLR基因启动子区DNA低甲基化致LDLR表达增高可能是Hcy引起VSMCs损伤的重要机制之一。     

The mechanism of LDLR promoter DNA methylation in the proliferation of VSMCs induced by homocysteine

目的 探讨低密度脂蛋白受体(LDLR)在同型半胱氨酸(Hcy)致血管平滑肌细胞(VSMCs)增殖中的作用机制.方法 原代培养VSMCs,用50、100、200及500 μmol/L Hcy干预72 h;MTT法观察VSMCs增殖的活性,ELSIA法和同位素法分别检测VSMCs中ox-LDL含量和DNA甲基转移酶活性;实时定量PCR和巢式降落式甲基化特异性PCR(nMS-PCR)检测LDLR的表达和启动子区DNA甲基化的状态.结果 随着Hcy浓度的增加,VSMCs中ox-LDL含量和DNA甲基转移酶活性明显增加,而VSMCs增殖活性下降,同时LDLR mRNA表达增高,且LDLR基因启动子区呈低甲基化状态,与对照组比较有显著性差异(P ＜0.05,P＜0.01).结论 LDLR基因启动子区DNA低甲基化致LDLR表达增高可能是Hcy引起VSMCs损伤的重要机制之一.     

同型半胱氨酸对人血管平滑肌细胞凋亡及半胱天冬酶-3表达的影响

目的：观察同型半胱氨酸(Hcy)对人血管平滑肌细胞（VSMCs）凋亡以及半胱天冬酶-3（caspases-3）表达的影响。 方法： 采用组织贴块法体外培养人VSMCs，流式细胞术检测人VSMCs细胞凋亡，逆转录-聚合酶链反应法检测caspases-3 mRNA的表达。 结果： 体外培养的人VSMCs在终浓度为500 μmol/L Hcy的培养液中孵育0 h、6 h、12 h、24 h、48 h后的细胞凋亡率分别为2.39％±0.47％、2.45％±0.64％、7.58％±1.02％、13.37％±4.71％、17.69％±3.13％，caspases-3 mRNA与GAPDH扩增条带吸光度(A)比值分别为0.24±0.08、0.29±0.10、0.89±0.26、1.37±0.24、1.82±0.53，表明Hcy呈时间依赖性诱导人VSMCs细胞凋亡和 caspases-3 mRNA的表达上调；在终浓度为0、100、200、500、1 000 μmol/L Hcy的培养液中孵育24 h后的细胞凋亡率分别为2.68％±0.23％、2.79％±0.12％、8.45％±2.41％、13.37％±4.71％、23.75％±5.56％，表明Hcy呈浓度依赖性诱导人VSMCs细胞凋亡。 结论： Hcy诱导人VSMCs凋亡可能是由caspase-3参与的死亡信号通路介导的，诱导人VSMCs凋亡可能是Hcy致动脉粥样硬化作用的机制之一。     

同型半胱氨酸对下丘脑-垂体条件培养基作用后的内皮细胞NO和脂过氧化物代谢的影响

血中同型半胱氨酸(homocysteine,Hcy)的浓度升高被认为是致动脉粥样硬化(atherosclerosis,AS)的危险因子,血浆Hcy水平与AS病程呈明显的剂量依赖关系。近年来的研究也发现Hcy可损伤内皮细胞(en-dothelial cells,EC),促进平滑肌细胞增殖,改变血液的抗凝状态及血小板功能,促进低密度脂蛋白的氧化等。因此,研究控制由Hcy引起EC受损有重要意义。     

金属硫蛋白抑制同型半胱氨酸诱导的大鼠血管平滑肌细胞增殖

目的:研究金属硫蛋白(MT)对同型半胱氨酸(Hcy)诱导大鼠血管平滑肌细胞(vascularsmoothmusclecells,VSMCs)增殖的影响及其作用机制。方法:以[³H]-TdR掺入法测定VSMCs增殖程度,免疫沉淀法测定VSMCs内丝裂素活化蛋白激酶(MAPK)活性,[¹⁰⁹Cd]-血红蛋白饱和法测定MT含量,硫代巴比妥酸法测定丙二醛(MDA)含量,NADH氧化法测定乳酸脱氢酶(LDH)漏出量。结果:Hcy(10^-6-10^-4mmol/L)呈浓度依赖性的刺激培养大鼠VSMCs[³H]-TdR掺入,0.1mmol/LHcy刺激[³H]-TdR掺入比对照组高4.2倍(P＜0.01)。Hcy亦呈浓度依赖性地激活VSMCsMAPK活性、增加细胞MDA的生成和LDH的漏出(P均<0.01)。单独MT孵育,对VSMCs的上述指标均无明显影响(P＞0.05)。但MT(10^-6-10^-4mol/L)呈浓度依赖性抑制100μmol/LHcy的促增殖效应(r=0.98,P＜0.01)。MT显著抑制Hcy对VSMCs的MAPK活性、MDA生成和LDH漏出的激活作用(均P＜0.01)。以0.5mmol/LZnCl₂预孵育6h后,VSMCsMT含量比非诱导细胞高5.7倍(P＜0.01),这种内源性MT高表达的细胞,显著抵抗Hcy刺激的-TdR掺入和MAPK激活;抑制Hcy的促细胞MDA生成与LDH漏出效应(均P＜0.01)。结论:MT能有效抑制Hcy促大鼠VMSCs增殖作用,其机制可能与MT拮抗Hcy对MAPK的激活和其抗氧化作用有关。     

同型半胱氨酸对大鼠血管平滑肌细胞分泌和表达IL-6的影响

目的:探讨同型半胱氨酸(Hcy)对大鼠血管平滑肌细胞(VSMCs)分泌和表达促炎性细胞因子白细胞介素-6(IL-6)的影响。方法:在大鼠主动脉平滑肌细胞培养基中加入不同浓度的Hcy, 并孵育不同时间。用ELISA法检测培养上清IL-6蛋白含量, 用半定量RT-PCR法检测IL-6mRNA表达。结果:0.25mmol/LHcy干预后, IL-6在6h开始高于对照组; 4.达峰值, 48h仍较对照组高;并且在一定的浓度范围内, Hcy呈剂量依赖性刺激VSMCs产生IL-6, 01mmol/L及0.25mmol/LHcy分别使IL-6产量较对照增多1.4和3.4倍。RT-PCR结果显示Hcy能刺激IL-6mRNA表达, 也呈剂量和时间依赖关系。结论:Hcy能促进VSMCs产生和表达IL-6、激活血管壁炎症反应, 这可能为其诱导动脉粥样硬化的重要机制之一。     

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.