引起幼儿腹泻的腺病毒的实验室诊断

目的研究引起幼儿腹泻的腺病毒的型别。方法取因腹泻住院的幼儿粪便标本．经PCR检测为腺病毒F组(Ad40或Ad41)阳性后,用293细胞分离病毒并培养,当细胞发生典型病变效应,刮下细胞备用：(1)固定,送电镜室检测;(2)按照湖北中医学院检验系实验室常用的方法提取病毒DNA。用SmaⅠ和HindⅢ2种限制性核酸内切酶消化腺病毒DNA并与文献报道的Ad40和Ad41的酶切图谱比较。结果5例阳性标本的PCR产物的大小是519bp．电镜可见细胞核内腺病毒晶格状排列;并且SmaⅠ和HindⅢ的酶切图与文献报道的Ad41图谱一致。结论用PCR和限制性核酸内切酶组合方法检测肠道腺病毒是可行的。     

Further studies on hybrid cell-surface antigens associated with human chromosome 11.

A new human immunogenetic cell-surface activity associated with human chromosome 11 in the AL human-Chinese hamster ovary cell hybrid is described. Like a1, but not a2, it is present on the human erythrocyte. By mutagenesis and selection, specific, stable, variants of the AL hybrid have been prepared exhibiting various combinations of a1, a2, a3, and lactic dehydrogenase A activities. The antigens of the AL system can be demonstrated by the horseradish peroxidase system which offers a promising approach to scanning of tissue cells.     

Further studies on the side reactions associated with use of N(pi)-benzyloxymethylhistidine

The use of N(alpha)-tert.-butyloxycarbonyl-N(pi)-benzyloxymethylhistidine [Boc-His(Bom)] in peptide synthesis results in a serious level of side products arising from the generation of formaldehyde during the HF cleavage reaction. In particular, when treating a His(Bom)-containing peptide having Cys at the N-terminus by HF, this leads to almost complete conversion of the Cys-peptide to thiazolidyl (Thz)-peptide unless precautions are taken. Also, the reaction of formaldehyde with the N-terminal Trp and the N-methylanthranyl (Nma) group was found to produce tetrahydro-beta-carboline and dihydroquinazolin derivatives, respectively, upon isolation from HF mixtures. The addition of cysteine as a scavenger in HF proved to be effective for suppressing modification arising from the generation of formaldehyde.     

Further inhibition studies on guanidinobenzoatase, a trypsin-like enzyme associated with tumour cells

Guanidinobenzoatase is a proteolytic enzyme capable of degrading fibronectin and is a tumour associated enzyme. Guanidinobenzoatase has been shown to be an arginine selective protease and is distinct from trypsin, plasminogen activator, plasmin, thrombin and a newly described tumour associated enzyme specific for guanidino phenylalanine residues. These conclusions have been derived from inhibition studies employing 4-methyl-p-guanidinobenzoate as substrate. Three active site titrants for trypsin have been shown to be good substrates for guanidinobenzoatase. A new active site titrant for trypsin, rhodamine bisguanidinobenzoate, can also be used to assay guanidinobenzoatase in a stoichiometric manner. This active site titrant can be employed to label guanidinobenzoate on the surface of leukaemia cells.     

Membrane cofactor protein is a receptor for adenoviruses associated with epidemic keratoconjunctivitis

Subgroup D adenovirus (Ad) types 8, 19, and 37 (Ad8, -19, and -37, respectively) are causative agents of epidemic keratoconjunctivitis and genital tract infections. Previous studies showed that Ad37 binds to a 50-kDa membrane glycoprotein expressed on human ocular (conjunctival) cells. To identify and characterize the role of the 50-kDa glycoprotein in Ad37 infection, we partially purified this molecule from solubilized Chang C conjunctival cell membranes by using lentil lectin chromatography and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Liquid chromatography coupled to nano-electrospray ionization-tandem mass spectrometry was subsequently used to identify four Ad37 receptor candidates: CD46, CD87, CD98, and CD147. Immunodepletion analyses demonstrated that the 50-kDa protein is identical to CD46 (also known as membrane cofactor protein). The Ad37, but not Ad5, fiber knob bound to the extracellular domain of CD46, demonstrating a direct interaction of an Ad37 capsid protein with CD46. An antibody specific for the N-terminal 19 amino acids of CD46 also blocked Ad37 infection of human cervical carcinoma and conjunctival cells, indicating a requirement for CD46 in infection. Finally, expression of a 50-kDa isoform of human CD46 in a CD46-null cell line increased cell binding by wild-type Ad37 and gene delivery by an Ad vector pseudotyped with the Ad37 fiber, but not by a vector bearing the Ad5 fiber. Together, these studies demonstrate that CD46 serves as an attachment receptor for Ad37 and shed further light on the cell entry pathway of subgroup D Ads.     

Further studies on fixation with osmium tetroxide

Summary The effect of buffered media containing dextran, sucrose and different organic ions, on the volume of blood and ascitescells during fixation with osmium tetroxide has been studied. The findings are in agreement with similar studies ontissue pieces as reported earlier. The presence of osmium tetroxide causes a marked swelling of the cells as estimated by hematocrit techniques. The swelling can be balanced by an appropriate composition of the fixation vehicle, the significance of which is discussed.

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Zusammenfassung Es wurde die Wirkung von Pufferlösungen, die Dextran, Sucrose und verschiedene organische Ionen enthalten, auf das Volumen von Blut- und Asciteszellen während der Fixation mit Osmiumtetroxyd untersucht. Die Ergebnisse stimmen mit ähnlichen Befunden anGewebsstücken, über die früher berichtet wurde, überein. Die Gegenwart von Osmiumtetroxyd verursacht eine bemerkenswerte Zellschwellung, die mittels Hämatokrit-Technik bestimmt wurde. Die Schwellung kann durch eine angepaßte Zusammensetzung verschiedener Fixierungszusätze ausgeglichen werden. Über die Bedeutung dieser Zusätze wird diskutiert.

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With 2 Figures in the Text     

Further studies on a hybrid cell-surface antigen associated with human chromosome 11 using a monoclonal antibody

A monoclonal antibody has been obtained that recognizes an antigen encoded by human chromosome 11. We present evidence that this monoclonal antibody recognizes the same or a similar antigenic activity as that previously called a1. Genetic information necessary for a1 expression and recognition by the monoclonal antibody both map to 11p13 leads to 11pter. Mutants that have lost a1 are no longer recognized by the monoclonal antibody. The macroglycolipid fraction of human erythrocyte membranes which contains the a1 antigenic activity is able to convert antigen-negative Chinese hamster ovary cells into cells which are killed by the monoclonal antibody plus complement.