脂肪间充质干细胞分化为内皮细胞并体外构建组织工程心脏瓣膜

背景：组织工程心脏瓣膜是利用组织工程技术将种子细胞种植于瓣膜支架上所构建的一种人工瓣膜,目前国内外研究主要集中于种子细胞来源及支架选择上。 目的：探讨人脂肪间充质干细胞体外向内皮细胞诱导分化后的细胞作为种子细胞,脱细胞猪主动脉瓣膜作为支架体外构建组织工程心脏瓣膜的可行性。 方法：利用吸脂术采集脂肪组织,分离、培养脂肪间充质干细胞,流式细胞仪鉴定细胞表型;免疫细胞化学方法及RT-PCR检测细胞分化标志物;应用Triton X-100联合胰蛋白酶的方法制备脱细胞猪主动脉瓣支架,将体外培养扩增的诱导分化后的内皮细胞种植于支架上构建组织工程心脏瓣膜,光镜及电镜下观察组织工程心脏瓣膜的组织学结构。 结果与结论：脂肪组织分离培养的脂肪间充质干细胞向内皮细胞诱导分化后表达CD31、CD34、CD144、Ⅷ因子和内皮型一氧化氮合成酶等内皮细胞特异性抗原;脱细胞猪主动脉瓣膜支架脱细胞完全,弹力纤维及胶原纤维保持完整;构建的组织工程心脏瓣膜可见支架上排列连续的单细胞层。提示脂肪间充质干细胞在体外向内皮细胞诱导分化后已初步具有内皮细胞功能,在脱细胞猪主动脉瓣膜支架上生长良好,可以在体外初步构建组织工程心脏瓣膜。     

骨髓间充质干细胞作血管组织工程种子细胞的研究进展

骨髓间充质干细胞易于分离培养，增殖能力强，体外培养多次传代后仍保持多向分化潜能其以自身多方面的特点已成为血管组织工程又一种可选择的种子细胞，对临床应用具有重要价值，但其进一步体外成血管的条件尚需深入研究。综述骨髓间充质干细胞hMSCs体外培养、定向分化为内皮细胞的条件及相关研究进展。     

骨髓间充质干细胞作血管组织工程种子细胞的研究进展

骨髓间充质干细胞易于分离培养,增殖能力强,体外培养多次传代后仍保持多向分化潜能其以自身多方面的特点已成为血管组织工程又一种可选择的种子细胞,对临床应用具有重要价值,但其进一步体外成血管的条件尚需深入研究。综述人骨髓间充质干细胞hMSCs体外培养、定向分化为内皮细胞的条件及相关研究进展。     

组织工程化血管种子细胞研究现状

种子细胞制取、培养、种植的研究是组织工程化血管研究的关键性环节。目前常用于作为组织工程化血管种子细胞的是白体血管壁细胞，如内皮细胞。造血系统来源的干细胞及间充质干细胞由于取材方便，可体外大量培养增殖，无免疫原性的优点，有望成为组织工程化血管的种子细胞主要来源，随着对胚胎干细胞的进一步研究，胚胎干细胞也可作为种子细胞。考虑到流体切应力对种子细胞的影响，动态培养种子细胞可促进种植后细胞的粘附性、细胞生长及功能的发挥，使组织工程血管更符合生理需要。     

人胎盘间充质干细胞促进血管生成

背景：构建组织工程化骨组织的同时,促进种子细胞与材料复合物内血液供应的重建成为研究的关键。胎盘间充质干细胞可以作为骨组织工程研究的种子细胞,研究其分化为血管内皮细胞以及促进血管生成有着重要意义。 目的：观察胎盘间充质干细胞在体外分化为血管内皮细胞以及体内促血管生成作用。 方法：分离培养人胎盘间充质干细胞,鉴定其表面抗原,经血管内皮生长因子和人碱性成纤维细胞生长因子联合体外诱导胎盘来源间充质干细胞向血管内皮细胞定向分化,诱导后细胞通过内皮细胞标志物KDR、v-WF染色鉴定。8只新西兰大白兔制成桡骨中段1.5 cm长的骨缺损模型,分别植入人胎盘间充质干细胞/丝素蛋白/羟基磷灰石和丝素蛋白/羟基磷灰石进行对照。植入后4,12周分别行大体观察、组织学观察和X射线观察,比较骨缺损修复以及血管生成情况。 结果与结论：胎盘间充质干细胞的诱导分化形态明显改变,胞体逐步回缩,立体感增强,内皮细胞标志物KDR、v-WF染色结果阳性。胎盘来源间充质干细胞与丝素蛋白/羟基磷灰石材料复合培养植入后,4周时新骨已开始形成,12周时有部分新生骨组织形成板层骨,骨小梁形成,内可见新生血管形成,而对照组支架材料降解较慢,未见新生血管。说明胎盘来源间充质干细胞体外可以分化为血管内皮细胞,与丝素蛋白/羟基磷灰石材料联合移植能够促进移植物内血管生成,较好的修复骨缺损。     

间充质干细胞构建组织工程化气管的研究与应用

背景：间充质干细胞诸多特有的良好生物学特性使得其在组织工程化气管研究中成为理想的种子细胞来源。 目的：总结间充质干细胞在构建组织工程化气管领域的研究现状、进展、存在的问题及展望。 方法：由作者检索PubMed数据库及CNKI数据库1979至2012年,在英文标题和摘要中以“mesenchymal stem cells, tissue-engineered trachea”和“tracheal chondrocytes, tracheal epithelial cells, tracheal vascular endothelial cells” 检索,中文文献检索中以“间充质干细胞、组织工程化气管、气管软骨细胞、气管上皮细胞和气管血管内皮细胞”为关键词,选择与组织工程化气管相关的文章,同一领域文献则选择近期发表或发表在权威杂志的文章,共纳入51篇。 结果与结论：组织工程化气管种子细胞研究主要包括软骨细胞、上皮细胞和血管内皮细胞。实验已证实, 间充质干细胞可定向分化为软骨细胞,细胞因子在诱导间充质干细胞分化为软骨过程中起着关键作用。目前尚未发现合适的诱导因子能特异性诱导间充质干细胞定向分化气管上皮细胞。有研究发现间充质干细胞具有向上皮细胞分化的潜能。间充质干细胞在体内或体外特殊条件下可诱导分化为血管内皮细胞,为间充质干细胞作为种子细胞分化血管内皮细胞应用于组织工程化气管起到借鉴作用。     

脂肪组织来源的干细胞的研究进展

来自中胚层的脂肪组织与骨髓组织一样含有大量能自我更新和多向系分化潜能的细胞群称为脂肪干细胞。其取材方便，来源丰富，可在体外稳定增殖传代。并与骨髓间充质干细胞有相似的多向分化表面标志CD105、STRO-1以及CD166受体。研究发现它具有多向系分化潜能，除可以分化为问充质来源的脂肪、骨，软骨、脂肪以及骨骼肌、心肌等细胞，也可诱导分化为来源于外胚层的神经细胞以及具有功能性的血管内皮细胞，用以修复骨、软骨、心肌、骨骼肌、血管以及神经等组织。其具有造血支持作用以及可被逆转录病毒、腺病毒以及慢病毒较高的转染效率等优点，可以作为基因转移良好的靶细胞。因而，脂肪来源的干细胞其有望成为组织工程、细胞治疗以及基因转染良好的种子细胞。     

脐血间充质干细胞的分离鉴定及其向脂肪和成骨的分化

目的分离鉴定脐血(UCB)中的间充质样干细胞(MLSC),探索其向脂肪和成骨分化的可行性。方法用羟乙基淀粉沉淀法分离脐血有核细胞,利用细胞贴壁生长特性分离纯化脐血间充质样干细胞;流式细胞仪检测其表面标志;多种成分联合诱导其向脂肪、成骨方向分化,细胞化学染色检测诱导后的细胞变化。结果培养得到一组间充质样干细胞,不表达造血细胞的标志(CD34/CD45/CD14)及内皮细胞的标志CD106,强表达间充质细胞的标志CD29、CD44和CD13,在适当的诱导条件下可向脂肪及成骨方向分化。结论脐血中含有间充质样干细胞,表达间充质干细胞的表面标记,并可以向脂肪、成骨方向分化,因此可以作为组织工程的种子细胞。     

脂肪源干细胞向血管内皮细胞的分化

背景：脂肪来源干细胞在体内储备丰富,体外增殖快速,具有多向分化潜能,是目前组织工程种子细胞的研究热点。近年来越来越多的研究表明脂肪干细胞在一定条件下可被诱导分化为内皮细胞,促进血管生成。 目的：观察兔脂肪干细胞体外分离培养及诱导分化为血管内皮细胞的生物学特性。 方法：取兔附睾处脂肪,采用胶原酶消化分离获得脂肪干细胞,体外培养至第3代后加入血管内皮细胞生长因子与碱性成纤维细胞生长因子联合诱导分化,对诱导前后细胞进行形态学观察、生长曲线测定、免疫组织化学染色及流式细胞仪表型检测。 结果与结论：兔脂肪干细胞生长旺盛,第3代兔脂肪干细胞呈成纤维细胞样,生长曲线呈“S”型,15代以内细胞形态未见明显变化。免疫荧光法检测Vimentin阳性,流式细胞仪检测CD44表达阳性,CD31表达阴性;诱导后细胞CD31表达阳性,CD44表达阴性。第3代兔脂肪干细胞向血管内皮细胞诱导分化21 d显微镜下呈铺路石样形态,血管内皮细胞第Ⅷ因子相关抗原染色细胞阳性,透射电镜下可见W-P小体。提示脂肪干细胞在体外可诱导分化为血管内皮细胞,可为组织工程血管提供理想的种子细胞。     

间充质干细胞诱导分化为血管内皮细胞的研究进展

间充质干细胞(Mesenchymal stem cells,MSCs)是一种起源于中胚层的成体干细胞,可以向所有中胚层来源的细胞及部分外胚层来源的细胞分化,且MSCs具有来源广泛、易于体外分离培养、免疫原性低,移植后无免疫排斥反应和易于基因转染等特点。血管内皮细胞属于中胚层细胞,MSCs可定向诱导分化为血管内皮细胞,在体外构建成理想的血管移植物,用于心脏组织工程瓣、血管组织工程以及再生医学领域。本文就间充质干细胞的生物学特性及诱导分化为内皮细胞的相关研究以及研究中存在的问题作一综述。     

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.