尼群地平对实验性糖尿病大鼠心肌收缩性的影响

腹腔注射链脲佐霉素（６５ｍｇ／ｋｇ）诱发Ｗｉｓｔａｒ大鼠糖尿病。糖尿病发病４周后,向饲料中加尼群地平（３０ｍｇ·ｋｇ－１·ｄ－１）。结果表明,糖尿病４周时大鼠心室舒张功能首先受损,８周后心室舒张和收缩功能均明显受累。尼群地平处理对糖尿病大鼠的心肌收缩性有一定的改善作用。提示尼群地平对大鼠糖尿病性心肌病有一定有益作用。     

山羊关节炎─脑炎前病毒的PCR检测

山羊关节炎─脑炎前病毒的ＰＣＲ检测相文华,丁恩雨,秦运安,吕晓玲,沈荣显（中国农业科学院哈尔滨兽医研究所哈尔滨１５０００１）关键词聚合酶链反应,山羊关节炎—脑炎病毒,整合山羊关节炎—脑炎（ＣａｐｒｉｎｅＡｒｔｈｒｉｔｉｓ－Ｅｎｃｅｐｈａｌｉｔｉｓ,Ｃ...     

霍山三种石斛与其栽培土壤中微量元素分布关系研究

本文应用灰色系统理论,对安徽霍山三种石斛与其栽培土壤中15种微量元素分布状况进行了关联分析．结果发现.其关联序为γ_根＞γ_叶＞γ_茎;γ_(-年茎)≈γ_(二年茎)≈γ_(三年茎);γ_(霍斛)＞γ_(铁斛)＞γ_(铜斛).可见霍山石斛与其栽培土壤间的微量元素相关性比其它石斛强,因而可通过增施微肥的办法来提高霍山石解中某些人体必需微量元素的含量．     

金属离子螯合剂对橙汁中L—抗坏血酸的保护及其机理探讨

本文研究了在加热过程中金属离子螯合剂植酸、聚磷酸钠和EDTANa_2对橙汁和橙汁模拟体系中L—抗坏血酸的稳定作用,并采用红外光谱和紫外差光谱对EDTANa_2的保护机理作了初步探讨。结果表明:植酸和聚磷酸钠均不能降低Cu~(2+)对橙汁模拟体系中L—抗坏血酸氧化降解的催化作用,而EDTANa_2不仅能络合Cu~(2+),减少L—抗坏血酸的催化降解损失,而且红外光谱和紫外差光谱及溶剂微扰研究还揭示出EDTANa_2可与L—抗坏血酸形成氢键保护,这种氢键保护作用受到糖和柠檬酸的不利影响。     

Evidence that methylation of the FMR-I locus is responsible for variable phenotypic expression of the fragile X syndrome.

DNA at the FMR-1 locus was analyzed by Southern blot using probe StB12.3 in an unusual fragile X family with six brothers, three of whom are affected with fragile X to varying degrees, two of whom are nonpenetrant carriers, and one of whom is unaffected. Fragile X chromosome studies, detailed physical examinations, and psychological testing were completed on all six. Two of the affected brothers and the two nonpenetrant brothers were found to be methylation mosaics. The three affected males spanned the phenotypic and cognitive spectrum of the fragile X syndrome. A correlation was seen between the degree of methylation and the phenotypic expression identified in the three affected males. The two males initially classified as nonpenetrant were found to have mild phenotypic expression which consisted of minor cognitive deficits and a partial physical phenotype. These two, who were negative on fragile X chromosome studies, were found on DNA analysis to have large broad smears, with approximately 97% of the DNA unmethylated. The results described here indicate that some "nonpenetrant" carrier males may have varying amounts of methylation of the FMR-1 region, which can result in mild expression of the fragile X syndrome. The apparently mild phenotypic and cognitive expression of the fragile X syndrome in the two males, initially classified as nonpenetrant, who are mosaic for hypermethylation of an expansion of the CGG repeat in the premutation range, indicates that expression of the syndrome is not confined to males with large, hypermethylated expansions (full mutation) but has instead a gradient effect with a threshold for the full expression of the phenotype.     

On-line monitoring of cell concentration of Perilla frutescens in a bioreactor

This article demonstrates the successful in situ real-time monitoring of the cell concentration of Perilla frutescens in a bioreactor by using a laser turbidimeter. It was found that turbidity measurements at 780 nm with the laser sensor were hardly affected by the red color of the anthocyanin produced by P. frutescens cells, nor by the aeration rate or agitation speed within the ranges investigated. There was an excellent linear relationship, with a correlation coefficient (r(2)) higher than 0.99, between the sensor's response and the cell concentration. The whole growth stage of the cells, i.e., lag, logarithmic, and stationary phases, in bioreactor cultivations, could be satisfactorily estimated on-line by means of the in situ turbidimeter. However, during the declining phase of the cells, an apparent deviation was observed between the on-line estimations and off-line measurements of cell concentrations by dry cell weight, while the wet cell weight could be estimated by the same turbidimeter system. We found that this deviation was caused by a decrease in the cell density due to an increase of the individual cell volume and a decrease of the cell dry weight during the declining phase. (c) 1993 John Wiley & Sons, Inc.     

盐酸胍诱导的α淀粉酶去折叠与再折叠

利用蛋白质内源荧光和酶活性两种信号以及荧光偏振,HPLC和停流等方法研究了盐酸胍诱导的α淀粉酶去折叠与重折叠的平衡转变和动力学。实验结果表明α淀粉酶去折叠与重折叠是两个不同的过程;变性与复性过程中可能伴有聚集体生成;去折叠与重折叠均为双相过程,重折叠大约始于2秒之后。     

黄花棘豆的喹诺里西定生物碱

豆科棘豆属有毒植物含多种有毒生物碱,有关棘豆属中生物碱成分的研究,早在1929年Couch由兰伯氏棘豆(Oxytropis lambertii DC.)中分离到一种多羟基化的含氮有机化合物,这是最早报道由棘豆属植物中分离出的生物碱成分,由于当时条件限制未能确定其结构。1982年美国农业部西部研究中心的植物化学家Molyneux从绢毛棘豆(Oxytropis sericea)中分离到苦马豆碱(swainsonine)等吲哚里西定生物碱(indolizidinealkaloids);1989年沈阳药学院于荣敏等由小花棘豆(Oxytropis glabra DC.)中分离出多种喹诺里西定生物碱。喹诺里西定生物碱具有多种生理活性,对试验动物中枢神经系统产生抑制,呼吸抑制或兴奋,致幻、流产和致畸等作用。本文报道由黄花棘豆(Oxytropis ochrocephala Bunge)中测得4种喹诺里西定生物碱。     

卡介苗对枯否细胞生物特性影响的免疫细胞化学研究

卡介苗(BCG)是增强肝枯否细胞(KC)抗肝癌细胞作用的最佳免疫制剂之一。本实验是给大鼠BCG后,应用溶菌酶免疫细胞化学法显示KC,以图象分析系统测定KC的数量、分布和面积,以细胞分光光度计测定KC溶菌酶活性;分离KC体外受BCG作用后,用ELISA法测定RC的Fc受体表达。结果显示:BCG使KC数量增多一倍,尤以肝小叶周边带为显著;KC体积明显增大,细胞面积增大55.71％,周边带KC面积增大一倍上;细胞溶菌酶光密度增大64.35％;Fc受体表达增强64.82％。上述结果是BCG增强KC抗肝癌细胞作用有关细胞学机制。