集总动力学模型研究的普遍方法与原则探讨

在积累了大量实践经验的基础上,结合石油加工过程中集总动力学模型的研究,对集总研究的普遍方法与原则进行了讨论与阐述,提出了几点自己的观点及应该注意的事项。     

成都地区汉族人群ACE基因多态性与血清ACE活性的相关性

为调查中国汉族人群血管紧张素转换酶(ACE) 基因多态性分布及与血清ACE(SA CE)活性的相关性.采用比色法和PCR技术,对90例健康汉族人群进行SACE活性和ACE基因插入/缺失(I/D)多态性的检测.结果显示:中国汉族人群ACE基因DD型占18%,DI型占44%,II 型占38%, D和I等位基因频率分别为0.40和0.60.ACE基因多态性与SACE活性密切相关,提示不同种族间ACE基因分布存在着差异,中国汉族人群ACE基因多态性以II型和I等位基因占优势;SACE活性受ACE基因I/D多态性的影响.     

环丙沙星与氧氟沙星联用抗结核药物肝毒性比较

目的　研究环丙沙星或氧氟沙星联用抗结核药的肝毒性并探讨其机制。方法　分别测定异烟肼和利福平联合用药 (IR)组及其分别联用氧氟沙星 (IRO)或环丙沙星 (IRC)组小鼠的血清谷氨酸氨基转移酶 (ALT)、肝指数、肝匀浆丙二醛 (MDA)含量、肝微粒体细胞色素P45 0和线粒体Ca2 ATP酶活性 ,及肝病理检查 ,结果与对照组以及实验组之间进行比较。结果　与正常对照组比较 ,IR组及IRO组的血清ALT、肝细胞匀浆MDA明显增高 (P <0 .0 5 ) ,而IRC组变化不大 (P >0 .0 5 ) ;同时发现IR组和IRO组的肝微粒体细胞色素P45 0含量较高和线粒体Ca2 ATP酶活性较低 ,而IRC组则相反 ;病理检查IRO和IRC组肝细胞坏死程度稍轻但与IR组比较无明显差异。结论　氧氟沙星、环丙沙星不增加异烟肼和利福平联用肝毒性 ,且环丙沙星有一定的拮抗作用。     

基因工程耐热碱性磷酸酯酶的表达与分离纯化

目的　获得可用于探针的非放射性标记的耐热碱性磷酸酯酶。方法　把耐热碱性磷酸酯酶的基因克隆入质粒pJLA5 0 3上 ,在E .coliMph44中表达。表达的酶用聚乙烯亚胺沉淀核酸 ,热变性 ,硫酸铵沉淀 ,层析等方法纯化。结果　经表达纯化后每克细菌可获得 1.5mg的酶 ,酶的纯度为 90 % ,比活为 78.4U/mg。结论　耐热碱性磷酸酯酶可在E .coliMph44中表达 ,表达的酶可用热变性和其它蛋白质纯化方法来纯化。     

ACEI对血压正常的早期糖尿病肾病治疗作用的Meta分析

目的：对血管紧张素转换酶抑制剂（ＡＣＥＩ）能否延缓血压正常的早期糖尿病肾病（ｄｉａｂｅｔｉｃ ｎｅｐｈｒｏｐａｔｈｙ,ＤＮ）患者的病情进展进行系统评价。方法：检索ＭＥＤＬＩＮＥ及中国生物医学文献数据库中收录的１９９０年１月至１９９９年４月间,有关ＡＣＥＩ对伴微量白蛋白尿的早期ＤＮ治疗作用的随机对照临床试验方面的文献。按照入选标准,最终有１０项随机对照临床试验纳入本研究。用ＲｅｖＭａｎ３．１软件对１     

高空吸纯氧和缺氧状态下对人体心肌酶的影响

目的 :研究人体在高空吸纯氧及缺氧状态下对血清心肌酶及心率的影响。方法 :将实验者分为吸纯氧组和缺氧组及对照组 ,前两组在 5km高空吸纯氧或不吸氧 ,对照组不升空 ,分别测定血清天冬氨酸氨基转移酶 (AST)、乳酸脱氢酶(LDH)、肌酸激酶 (CK)、α 羟丁酸脱氢酶 (α HBCH)和心率变化。结果 :在 5km高空 ,缺氧时CK增高明显 (P <0 .0 5) ,血清心肌酶活性随吸纯氧时间延长有逐渐增高的趋势 ;吸纯氧时血清心肌酶活性随时间延长有逐渐增高的趋势 ,缺氧时心率随缺氧时间延长而逐渐加快。结论 :长时间吸纯氧或缺氧都将对机体产生损害     

贲门癌患者围手术期上消化道动力学观察

目的观察贲门癌对食管运动功能的影响以及手术后残余食管、残胃的运动功能改变。方法　用低顺应性三腔聚乙烯液压毛细管灌注导管对22例正常人和31例中晚期贲门癌患者进行了食管压力测定。所有受检者均仰卧位,每次吞咽5ml水,采用定点牵拉法。计算机自动计算出各部位的静息压、收缩压、收缩及松弛时间、传播速度。结果贲门癌患者手术前与正常人的各项指标(除下括约肌外)相比较,贲门癌患者食管下段收缩时间明显长于正常人。贲门癌患者手术前后的数据比较:①手术后上括约肌收缩压明显高于手术前。②手术后食管上段静息压和收缩压均明显高于手术前。③手术后食管中段收缩压明显低于手术前。④手术后胃的压力明显低于手术前。⑤手术后食管中段静息压明显低于胃的压力。结论①贲门癌这一疾病并未改变食管运动功能。②手术后近期吻合口处有一高压带,可起到阻止胃腔正压向食管腔传递的压力屏障作用。③手术使食管中段收缩运动功能减弱。④术后反射性引起食管上段收缩增强,从功能上讲似能阻止可能发生的食管咽返流。     

POLYMORPHISM OF ANGIOTENSIN-CONVERTING ENZYME GENE AND GENETIC SUSCEPTIBILITY TO ASTHMA WITH FAMILIAL AGGREGATION

Objective. Angiotensin-converting enzyme (ACE) plays a key role in the metabolism of angiotensin Ⅱ (AT Ⅱ) and inactivation of bradykinins and tachykinins, which are potent bronchialconstrictors and mediators of inflammation asthma, and ACE is heavily expressed in the lungs. An insertion-deletion (D/I) polymorphism of ACE gene has been shown to be associated with levels of ACE. We investigate whether the polymorphism of ACE gene is associated with asthma and bronchial responsiveness.Methods. A case-control study was carried out in 50 asthmatics, 7 families with at least 2 asthmatic individuals, and 50 healthy subjects. The insertion/deletion (I/D) polymorphism of ACE gene was amplified by polymerase chain reaction (PCR). Methacholine brocho-provocation and pulmonary function tests were performed in all asthmatics. Results. There was an higher gene frequency of DD genotype of ACE gene in asthmatic subjects and families individuals compared with healthy subjects (46%, 53% vs 16%, P＜0.05; odd ratio 4.98). Anhigher prevalence of DD genotype of ACE was in patients with bronchial hyperresposiveness (BHR) (67%vs 33%, P＜0.05; odd ratio 3.8). Accordingly, the mean values of FEV1% and FEV1/FVC were higher in asthmatics carrying non-DD alleles than patients with DD genotype (73.78% vs 56.56%, P＜0.05; 79.19% vs 69.29%, P＜0.05, respectively).Conclusion. These results suggested that DD allele of ACE genotype was significantly involved in genetic susceptibility to asthma. DD genotype of ACE might be a risk factor for the degree of airway obstruction, it could also be implicated in pathogenesis of bronchial hyperresponsiveness.     

MTT显色反应实验条件分析

目的 :检验分析MTT实验方法本底高、灵敏度低、稳定性差的影响因素 ,改进实验条件提高灵敏度和稳定性 ,降低本底。方法 :用MTT比色方法 ,细胞毒试验及细胞增殖实验 ,分析比较不同条件下MTT显色反应的性能特点。结果 :比较了 13种溶剂对Formazan的溶解性能。分析检验了琥珀酸脱氢酶在细胞上的分布特点、pH值对MTT反应体系的影响、酚红和牛血清对检验结果的影响 ,提出相应对策。检测了MTT反应时间曲线和细胞活力曲线。分析了改进后的MTT实验方法的灵敏度和稳定性。结论 :以MTT为底物的酶在细胞代谢中主要分布在细胞膜表面。MTT反应体系的pH值为 6 7,比较好的Formazan溶剂是正丙醇、异丙醇和乙二醇乙醚。去掉细胞培养上清 ,检测细胞上的酶 ,用溶剂使蛋白质变性 ,经沉淀去掉蛋白质影响 ,能使MTT实验方法的本底降低 ,灵敏度提高。通常情况下该方法检测K 5 62细胞和人淋巴细胞的灵敏度分别为 10 0 0和 10 0 0 0个细胞左右。     

The effect of big endothelin-1 in the proximal tubule of the rat kidney

1. An obligatory step in the biosynthesis of endothelin-1 (ET-1) is the conversion of its inactive precursor, big ET-1, into the mature form by the action of specific, phosphoramidon-sensitive, endothelin converting enzyme(s) (ECE). Disparate effects of big ET-1 and ET-1 on renal tubule function suggest that big ET-1 might directly influence renal tubule function. Therefore, the role of the enzymatic conversion of big ET-1 into ET-1 in eliciting the functional response (generation of 1,2-diacylglycerol) to big ET-1 was studied in the rat proximal tubules.
2. In renal cortical slices incubated with big ET-1, pretreatment with phosphoramidon (an ECE inhibitor) reduced tissue immunoreactive ET-1 to a level similar to that of cortical tissue not exposed to big ET-1. This confirms the presence and effectiveness of ECE inhibition by phosphoramidon.
3. In freshly isolated proximal tubule cells, big ET-1 stimulated the generation of 1,2-diacylglycerol (DAG) in a time- and dose-dependent manner. Neither phosphoramidon nor chymostatin, a chymase inhibitor, influenced the generation of DAG evoked by big ET-1.
4. Big ET-1-dependent synthesis of DAG was found in the brush-border membrane. It was unaffected by BQ123, an ET_A receptor antagonist, but was blocked by bosentan, an ET_A,B-nonselective endothelin receptor antagonist.
5. These results suggest that the proximal tubule is a site for the direct effect of big ET-1 in the rat kidney. The effect of big ET-1 is confined to the brush-border membrane of the proximal tubule, which may be the site of big ET-1-sensitive receptors.