大肠菌群MPN检测法在药品微生物限度检查中的应用

采用大肠菌群作为卫生指示菌,对口服药品进行细菌学检验,实验结果表明有利于口服药品染菌状况的监督与控制。     

4种头孢菌素的抗生素后效应影响因素

目的：研究头孢呋辛（ＣＸＭ）、头孢噻肟（ＣＴＸ）、头孢哌酮（ＣＰＺ）、头孢地嗪（ＣＤＺＭ）的抗生素后效应及药物浓度、接触时间、菌种等因素的影响。方法：采用ＡＶＡＮＴＡＧＥ全勇自动微生物分析仪、用光密度法测定４种抗生素不同浓度对２种共１２株临床常见致病菌不同反应时间的体外抗生素后效应（ＰＡＥ）。结果：４种头孢菌素类药物对革兰阳性球菌有较明显的ＰＡＥ，对革兰阴性杆菌ＰＡＥ较小甚至没有或为负值；药物浓度     

高血压鼠局部脑梗塞后脑超微结构改变动态观察

本文选用肾血管性高血压鼠(RHR)复制大脑中动脉闭塞(MCAO)模型,其后2h至7d分8次取不同区域脑组织进行透射电镜动态观察超微结构的改变。显示局部脑梗塞后发生全脑性改变,其损害程度和出现时间梗塞区最早,以坏死为主,呈完全不可逆性损害;边缘区稍后,主要是微血管塌陷和微血栓形成及部分脑细胞坏死,呈部分可逆性损害,远隔区和镜区最迟,以内皮和星形细胞水肿为主,呈可逆性损害,认为用RHR复制MCAO,更接近于高血压性脑血管损害基础上发生脑梗塞的临床病理改变,全脑超微结构的动态性改变中微血管损害起着重要作用。     

小儿胃膀胱扩大成形术

采用胃膀胱扩大成形术，用于小儿下尿路再建以保护上尿路，控制尿失禁并评价其疗效。３例女性患儿（平均年龄９岁）行带血管蒂胃组织片膀胱扩大成形术。术后随访８个月至２年。３例患儿膀胱容量从术前２０～３０ｍｌ增至２５０～３００ｍｌ，２例排尿控制满意，１例能部分控制排尿。上尿路功能改善２例，稳定１例。血浆电解质成分无改变。胃组织的解剖及代谢特点使胃膀胱扩大成形术不失为小儿下尿路再建的一个重要方法。     

Isolation, affinity purification, and identification of piglet small intestine mucosa receptor for enterotoxigenic Escherichia coli k88ac+ fimbriae

An affinity chromatography technique was utilized to isolate and purify the receptors of Escherichia coli K88ac(+) fimbriae from the mucus of the small intestines of newborn piglets. Purified K88ac+ fimbriae were covalently immobilized onto a beaded agarose matrix (Sepharose 4B). The immobilized fimbriae were used for the affinity purification of the K88ac+ receptors. Only two major proteins were tightly and specifically bound to the immobilized fimbriae after the column containing bound receptor was washed exhaustively with a buffer containing a high concentration of salt and a detergent. The receptors were eluted as a single component at a low pH. The isolated proteins were then subjected to enzyme-linked immunosorbent assay, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western blot (immunoblot) analyses. The two proteins were of high purity, were responsible for nearly all of the fimbrial binding capacity of the crude mucus, and had molecular masses of 26 and 41 kDa. The method for isolation of E. coli binding proteins is simple and yields purified intestinal receptors in a single chromatographic run. The intestinal mucus of different piglets has different proportions of the two receptor proteins.     

Translocation of Enterococcus faecalis strains across a monolayer of polarized human enterocyte-like T84 cells

We used a two-chamber system to study transcytosis of Enterococcus faecalis across monolayers of human colon carcinoma-derived T84 cells, which show structural resemblance to the native intestine. Among 16 E. faecalis isolates from different sources, the well-characterized strain OG1RF and 8 other isolates (2 endocarditis isolates, 1 urine isolate, and all 5 fecal isolates) showed translocation in this assay, while 6 clinical isolates (3 endocarditis and 3 urine isolates), the recipient strain JH2-2, and the control, Escherichia coli DH5alpha, had no detectable translocation. Of two OG1RF mutants involving the previously studied epa (enterococcal polysaccharide antigen) gene cluster, known to be needed for virulence and resistance to killing by polymorphonuclear leukocytes, one epa mutant (TX5179) was unable to translocate, while TX5180, with an epa disruption farther downstream, showed a moderate decrease in translocation relative to that of the wild-type strain OG1RF (P < 0.01), indicating that the epa gene cluster is important for translocation across a T84 monolayer. This observation was confirmed by complementation of the epa mutant (TX5179) with epa genes and restoration of its translocation ability. In conclusion, we have demonstrated translocation of at least some strains of E. faecalis across T84 monolayers, although strains differ considerably in this ability, and we have demonstrated that epa mutations can cause marked changes in successful translocation. These results suggest that this model may be a useful in vitro system for studying the process of translocation from the intestinal tract.     

Proteolysis-independent regulation of PI3K by Cbl-b-mediated ubiquitination in T cells

Cbl-b, a ring-type E3 ubiquitin protein ligase, is implicated in setting the threshold of T lymphocyte activation. The p85 regulatory subunit of phosphatidylinositol 3 kinase (PI3K) was identified as a substrate for Cbl-b. We have shown that Cbl-b negatively regulated p85 in a proteolysis-independent manner. Cbl-b is involved in the recruitment of p85 to CD28 and T cell antigen receptor zeta through its E3 ubiquitin ligase activity. The enhanced activation of Cbl-b(-/-) T cells was suppressed by the inhibition of PI3K. The results suggest a proteolysis-independent function for Cbl-b in the modification of protein recruitment.