Mecillinam susceptibility as an indicator of β-lactamase production in Staphylococcus aureus

The use of direct susceptibility testing from specimens has led to the fortuitous observation that penicillin-susceptible strains have larger inhibition zones for mecillinam than do β -lactamase producers. The current study was, therefore, undertaken to test 179 Staphylococcus aureus isolates for mecillinam susceptibility by Rosco Neo-Sensitabs and to compare the results with commonly used tests for β -lactamase production, i.e. size and character of penicillin inhibition zones, chromogenic cephalosporin (nitrocefin) tests and clover leaf assays. Agreement between methods was reached for 175 of 179 strains when disregarding the results of the nitrocefin tests, 88 isolates being found susceptible and 87 being found to be β -lactamase producers. All 88 susceptible isolates had mecillinam zones of >22 mm, with the great majority being >25 mm; double zones did, however, occur. The 87 β -lactamase producers had zones <14 mm or no zones. Four isolates presenting problems in had mecillinam zones of ≤20 mm and were without tapering growth at the penicillin inhibition zone edge. In conclusion, the size of the mecillinam inhibition zone is found to be a useful supplementary test in the clinically important distinction between β -lactamase-producing and non-producing isolates of S. aureus .     

Biochemical and ultrastructural alterations produced by miconazole and econazole in Trypanosoma cruzi

Miconazole and econazole, two fungicide imidazole derivatives, completely inhibited growth of Trypanosoma cruzi (Tulahuen strain) at concentrations of about 20 muM. Culturing of T. cruzi in the presence of lower doses of imidazole derivatives produced: decrease of 5,7-diene sterol content in epimastigotes (including ergosterol); disappearance of the nuclear chromatin, vacuolization and decrease in the electron density of the cytoplasm; selective surface alterations as revealed by an increased response to wheat-germ- and phytohemagglutinin. At variance with the effect of miconazole on Candida (De Nollin et al. (1977) Antimicrobial. Agents Chemother. 11, 500-513), miconazole and econazole, under the experimental conditions used, did not increase the rate of hydrogen peroxide generation by T. cruzi.     

Heparin effect on ionised calcium concentration

The effect of heparin on plasma ionised calcium was studied by adding it in increasing amounts to whole blood from 10 normal subjects. There was no significant change in ionised calcium from the addition of 1 U/ml but a significant fall of 0.02 mmol/1 when 2 U/ml were added and a progressive further fall with increasing concentrations. Heparin from three different manufacturers produced similar results. The effect of heparinisation in vivo was studied during regular haemodialysis on 10 patients with chronic renal failure. Following intravenous injection of 10000 U of heparin there was a consistent and significant fall averaging 0.03 mmol/l.     

油菜吲哚硫苷降解物对S180小鼠抗肿瘤作用的实验研究

目的 探讨油菜资源中吲哚硫苷降解物对肿瘤的抑制作用及对免疫功能的影响。方法 分别将两种不同提取法制备的高、低浓度的吲哚硫苷对S180小鼠ig给药，ip环磷酰胺。结果 吲哚硫苷降解物2号高浓度和吲哚硫苷降解物1号低浓度治疗组与生理盐水对照组相比有明显的抑制作用，能增加淋巴细胞转化率。结论 吲哚硫苷降解物可能是通过增强机体免疫功能来抑制移植性肿瘤生长，起到抗肿瘤的作用。     

用PCR—RFLP和16SrDNA指纹图法分析幽门螺杆菌基因型

本文建立了PCR－RFLP和16srDNA指纹图法．对19株幽门螺杆菌（HP）进行基因型分析：HP尿素酶C基因的PCR扩增产物．分别用HindⅢ、HaeⅢ、AluⅠ酶切，结果显示：每个酶均将19株HP分为3种RFLP图谱．综合HindⅢ，HaeⅢ和AluⅠ酶切结果，19株HP分为10个酶切带型；PCR扩增HP标准株16SrRNA基因，地高辛标记制备550bp探针，19株HPDNA分别经HaeⅢ和EcoRⅠ酶切、电泳后，通过Southern杂交获16SrDNA指纹图，结果显示：HaeⅢ酶切分为14个杂交带型，EcoRⅠ酶切19株HP杂交带型均不同。本实验表明：上述两种方法重复性好，分群力高，可准确有效地对HP作出鉴定并将其分型。19株HP株间存在基因型差异。     

新抗喘药物的研究——茶碱衍生物及卤代苯乙醇胺化合物的合成

本文根据β_2-受体兴奋剂和茶碱类药物的作用机制,结合两类药物的基本结构和构效关系,运用新药设计中的拼合原理及生物电子等排原理,设计扦合成了两类共十六个尚未见于文献报导的化合物。经初步药理实验证明均具有抗哮喘作用,其中I_(5-8)活性较高,且对心脏副作用轻微,可望成为治疗哮喘的新药。     

新生儿脑病S-100蛋白监测与预后的研究进展

目的:通过监测新生儿缺氧缺血性脑病(HIE)患儿血清中S-100蛋白含量的动态变化,建立对HIE患儿的早期科学诊断及预后评估技术指标。并探讨S-100蛋白浓度变化与病情的严重程度及转归之间的关系。方法:采用酶联免疫吸附试验、双抗体夹心法检测,对120例HIE有症状组患儿(HIE轻度症状组40例,HIE中度症状组40例,HIE重度症状组40例)和40例新生儿窒息组患儿与40例对照组健康新生儿血清S-100蛋白含量进行检测,并进行动态观察。结果:①HIE有症状组不同时期血清S-100蛋白含量均显著高于对照组(P<0.01);②新生儿窒息组不同时期的血清S-100蛋白含量也明显高于对照组(P<0.01);③HIE有症状组血清S-100蛋白含量明显高于新生儿窒息组(P<0.05)。结论:HIE有症状组患儿病情越重,其血清S-100蛋白含量则越高,提示血清S-100蛋白可作为判断HIE病情程度的客观依据和早期诊断以及预后评估HIE的主要指标。     

Kringle 5的真核植物细胞穿梭表达载体的构建

目的：构建含有目的基因kring5的真核植物细胞穿酸表达载体。方法：应用RT－PCR方法，从正常人肝脏组织中获得kringle5基因，测序后，再通过DNA重组技术，将kringle5基因片段克隆到真核植物细胞表达载体pBI121和pCAMBIA3301上。结果：得到的kringle5基因序列测定结果与文献相符，重组载体pB1k5和pC33k5经酶切鉴定正确，含有植物高效表达CaMV35S启动子。结论：重组载体pB1k5和pC33k5不仅可以在大肠杆菌中稳定复制，而且可以在植物细胞中表达。     

头孢呋辛酯制备工艺的改进

以头孢呋辛钠为原料，从制备（R，S）-乙酸1-溴乙酯开始。经酯化反应的溶剂沉淀过程无须分离直接制得高纯度非晶型的头孢呋辛酯。本制备方法简便，适于工为化生产。