葡萄球菌的分离鉴定及药敏分析

目的：了解不同种类葡萄球菌在本院临床标本中的感染情况及耐药性，为临床治疗和控制此类感染提供参考。方法：采用VITEK-AMS GPI卡进行鉴定，纸片扩散法(NCCLS)及GPS卡进行药敏实验、β内酰胺酶测定和MRS检测，并结合临床资料进行分析。结果：总共3753株感染菌中822株为葡萄球菌(21．90％)，其中金黄色葡萄球菌(SA)322株(39．17％)，凝固酶阴性葡萄球菌(CNS)500株(60．83％)。SA中293株(90．99％)产生β内酰胺酶，苯唑西林耐药者(MRSA)183株(56．83％)；CNS中450株(90．00％)产生β内酰胺酶，苯唑西林耐药的凝固酶阴性葡萄球菌(MRCNS)350株(70．00％)。结论：葡萄球菌特别是凝固酶阴性葡萄球菌是临床感染的主要致病菌之一；万古霉素是有效治疗苯唑西林耐药的葡萄球菌(MRS)的唯一可选药物；合理使用抗生素对治疗和控制感染至关重要。     

增生性玻璃体视网膜病变基质金属蛋白酶的定量研究

目的:研究增生性玻璃体视网膜病变(proliferative vitreoretinopathy,PVR)玻璃体中基质金属蛋白酶(matrix metalloproteinases,MMPs)的表达,探讨MMPs在PVR病理过程中的作用。方法:PVR患者采用标准三切口巩膜扁平部玻璃体切割术(pars plana vitrectomy,PPV),取未稀释的玻璃体21只眼,PPV术后复发的玻璃体腔液20只眼,意外死亡的正常人玻璃体10只眼,采用明胶酶谱分析法定量分析MMP-2和MMP-9活性水平。结果:PVR玻璃体有MMP-2活性水平增高,与正常玻璃体比较差异有显著性意义(P<0.05)。21眼PVR玻璃体中13只眼有MMP-9活性水平增高,平均(171.52±13.17)扫描单位。20眼PPV术后PVR复发的玻璃体腔液19只眼有MMP-9活性水平增高,平均(156.01±37.21)扫描单位。正常人玻璃体无MMP-9的表达。结论:PVR玻璃体有MMP-2和MMP-9活性水平增高,MMP-9活性水平增高可能与术后PVR复发有关。眼科学报2003;19:130-132。     

新生儿脐炎85例脐部分泌物细菌学分析

目的：了解新生儿脐部感染细菌学状况，为临床提供预防及治疗参考。方法：调查我院1997年1月－2002年6月收治的有完善细菌学资料的新生儿脐炎85例，对所获得的98例致病菌的种类及药敏状况进行分析。结果：社会获得性感染主要致病菌为G^ 球菌（70．5％），金黄色葡萄球菌占比例较高。医院感染主要致病菌为C^-杆菌（51．4％），以大肠埃希菌占比例较高。两类感染所分离的细菌均具有多重耐药性，但对氨基糖苷类及喹诺酮类耐药率较低，其次是第三代头孢菌素类抗生素。结论：临床对新生儿脐部感染，特别是有严重感染中毒症状时，应首先考虑使用第三代头孢菌素类抗生素。     

根据桂枝汤的效应消除半衰期和表观消除半衰期制订给药方案的探讨

为探讨药效法估测的效应消除半衰期和效量法估测的表观半衰期对合理制订给药方案的意义和作用,以桂枝汤解热和抗炎的药物动力学实验中所得的相应参数值设计了给药方案,观察了它们在提高药效上的作用。结果表明在给药总剂量相等、首次给药同时开始的情况下,以半衰期设计的给药方案组的药效均明显高于习惯的一次给药组;而以效应消除半衰期设计给药方案组药效增强率又高于以表观半衰期设计的方案组。提示效应消除半衰期比表观半衰期似更有实践意义。     

Absence of structural alterations of the multidrug resistance genes in transitional cell carcinoma

Summary Tumor DNA from 27 patients with treated or untreated transitional cell carcinomas of the urinary tract was screened for genomic alterations of the multidrug resistance genes in order to determine whether structural changes of these genes are important in primary urothelial tumors. None of the tumors showed evidence of amplification or rearrangements of either mdr1 or mdr2. The lack of amplification or rearrangements observed in these tumors suggests that structural alterations of the mdr1 and mdr2 genes are not important mediators of drug resistance in TCC.Supported in part by grant CA-34775 from the National Institutes of Health and by a grant from the Heckscher Foundation for ChildrenDr. Klein is a fellow of the American Cancer Society     

Antimetastatic Activity of Polymeric RGDT Peptides Conjugated with Poly(ethylene glycol)

Polymeric peptides containing defined repetitive or cyclic structures of RGDT sequence, (RGDT)_n (n = 1 to 11) and cyclo(RGDT)_n (n=2 to 4), at a dose of 500 μg exhibited an inhibitory effect on experimental lung metastasis upon co-injection with tumor cells and the magnitude of the effect increased in parallel with the increase of degree of repetition of the RGDT sequence. The conjugation of (RGDT)_n (n = 1, 5, 11) with poly(ethylene glycol), PEG as a polymeric carrier led to enhanced inhibition of lung metastasis in proportion to the degree of RGDT sequence repetition and in a dose-dependent manner. Multiple i.v. administrations of PEG-(RGDT)₁₁, at 2-day and 3-day intervals before the excision of primary tumors, effectively inhibited spontaneous lung metastasis by s.c. inoculation of tumors, whereas (RGDT)₁₁ exhibited inhibition of lung metastasis only when given at 2-day intervals. This indicates that the conjugation of PEG with (RGDT)_n allowed the prolongation of administration interval, implying a sustained inhibitory effect on tumor metastasis. In support of this supposition, a decrease in the arrest of radiolabeled tumor cells in the lungs was observed when PEG-(RGDT)₁₁ was co-injected i.v. with tumor cells, or injected i.v. one day before tumor inoculation. In contrast, (RGDT)₁₁ significantly inhibited the tumor cell arrest in the lungs only upon co-injection with tumor cells. We also noted that (RGDT)_n, cyclo(RGDT)_n and PEG-(RGDT)₁₁ inhibited tumor cell invasion into Matrigel in a concentration-dependent manner and in proportion to the degree of RGDT sequence repetition, indicating that the peptide-mediated antimetastatic effect is partly associated with the anti-invasive potential. Thus, the conjugation of anti-cell adhesive and antimetastatic RGDT peptide with PEG might provide a therapeutically promising basis for the prevention of cancer metastasis (“anti adhesion therapy”).     

New approaches to QSAR: Neural networks and machine learning

Summary Neural networks and machine learning are two methods that are increasingly being used to model QSARs. They make few statistical assumptions and are nonlinear and nonparametric. We describe back-propagation from the field of neural networks, and GOLEM from machine learning, and illustrate their learning mechanisms using a simple expository problem. Back-propagation and GOLEM are then compared with multiple linear regression (using the parameters and their squares) on two real drug design problems: the inhibition ofEscherichia coli dihydrofolate reductase (DHFR) by pyrimidines and the inhibition of rat/mouse tumour DHFR by triazines.     

青霉烷砜对氨苄青霉素的增效作用

观察加用青霉烷砜后氨苄青霉素对痢疾杆菌的体外杀菌效果。结果表明,加用青霉烷砜后对69株痢疾杆菌的杀菌效果,从单纯氨苄青霉素的杀菌率59.4％(41/69)提高到98.6％(68/69),有显著增效作用(P<0.005)。各株痢疾杆菌对国产和墨西哥产氨苄青霉素的敏感性无差异。证明青霉烷砜对氨苄青霉素有增效作用,对原耐氨苄青霉素痢疾杆菌的杀菌率达96.4％(27/28)。对耐药痢疾杆菌治疗药物的选择提供了有益的参考。