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Biomedical subjects

J L Melnick

Publications and source records attributed to J L Melnick.

At least 271 records · Page 15Linked to original sources
PubMed1973

Lyophilized combination pools of enterovirus equine antisera: preparation and test procedures for the identification of field strains of 42 enteroviruses.

This paper describes the preparation of 8 dried pools (designated A to H) of sera. Each pool is composed of 10 or 11 of 42 individual enterovirus equine sera and contains 500 antibody units of each serum component per 0.1 ml. Procedures for using the antiserum pools are given, and guidance is provided for interpreting the results of serum neutralization tests in identifying field isolates.

Animals↗
PubMed1973

WHO collaborative studies on enterovirus reference antisera; fourth report.

This paper summarizes the results of the fourth part of a comprehensive programme undertaken by the WHO International Reference Centre for Enteroviruses and other laboratories for the testing of enterovirus equine antisera prepared for long-term use as reference antisera. The studies were designed to appraise the specificity of the immune serum of horses inoculated with prototype enteroviruses (coxsackievirus types A2, 4, 8, 10, 11, 14-16, 18-21, and 24, and echoviruses E21, 27, 30, 31, and 33). Tests for neutralizing antibody were performed against the homologous viruses and against available regional homotypic strains. Heterotypic tests were performed against reoviruses 1-3, adenoviruses 1-31, and the entire series of enteroviruses (with the exception of enterovirus 68). The homologous geometric mean titre of the 5 echovirus antisera ranged from 3 000 to 10 000; the titre of 1 coxsackievirus antiserum (A24) was only about 400, but the titres of the others ranged from 1 500 to 14 000. All corresponding preinoculation sera were negative. Heterotypic antibody of significant titre was found in 4 antisera: E31 serum against E5 virus, CA8 serum against CA3 virus, CA13 serum against CA18 virus, and CA15 serum against CA2 virus. Information on other heterotypic antibody titres (where found) is recorded for guidance in the use of the sera. The results of homotypic tests with viruses isolated by the collaborating laboratories, though limited in number, were satisfactory.

Adenoviridae↗
PubMed1973

Enterovirus type 70: the etiologic agent of pandemic acute haemorrhagic conjunctivitis.

A new enterovirus, now classified as enterovirus type 70, was isolated from the conjunctiva of patients with acute haemorrhagic conjunctivitis during the 1971 epidemics that occurred in Japan, Singapore, and Morocco. These epidemics were parts of a pandemic involving Africa (Algeria, Ghana, Morocco, Nigeria, and Tunisia), Asia (Cambodia, China (Province of Taiwan), Hong Kong, India, Indonesia, Japan, Malaysia, the Philippines, Singapore, and Thailand), and England during 1969-71. A representative strain from each of the three epidemic areas was studied cooperatively. The strains exhibited the physicochemical characteristics of enteroviruses. Cross-neutralization tests showed that these viruses were distinct from all known human enterovirus immunotypes, but that they were antigenically closely related. The human origin of the viruses was demonstrated by the appearance of homologous neutralizing antibodies during convalescence in patients with acute haemorrhagic conjunctivitis.

Acute Disease↗
PubMed1972

Enterovirus concentration on cellulose membranes.

Cellulose nitrate membranes were used as one of the adsorbents in concentrating viruses from water. For adsorption to occur, salts were required. With increase in valency of salt, less salt was necessary for enhanced virus adsorption to membranes. Trivalent salts were more effective because they could be used at only 1% the concentration required for divalent salts. Thus, 0.5 mM AlCl(3) was as effective as 50 mM MgCl(2). For testing 500 gal of water, only 0.24 kg of AlCl(3) was required in contrast to 20 kg of MgCl(2). Virus could then be eluted from such membranes, having an area of 486 cm(2), with 250 ml of pH 11.5 buffer. Lowering the pH of the eluate and adding AlCl(3) permitted the virus to be quickly readsorbed on a smaller cellulose membrane, i.e., 4 cm(2). Virus for assay was eluted from the small membrane in 1 ml. This procedure has provided the basis for concentrating minute amounts of virus from large volumes of water.

Adsorption↗
PubMed1972

Concentration and purification of influenza virus on insoluble polyelectrolytes.

A method for rapid concentration and purification of influenza virus by adsorption on and elution from an insoluble polyelectrolyte is described. To accomplish this task, influenza virus had to be rendered stable at pH 4 to 5, since viruses adsorb to the polyelectrolyte more efficiently at this pH range. A precipitate which forms in influenza harvests under acid conditions in the cold can be removed by ammonium sulfate at a concentration which traps the precipitate but not the virus. Thus, ammonium sulfate-treated influenza virus in allantoic fluid could be readily concentrated on the polyelectrolyte. Elution yielded a virus concentrate essentially free of nonviral proteins.

Adsorption↗
PubMed1972

Photodynamic treatment of herpes keratitis.

Photodynamic inactivation of virus was tested as a potential therapeutic tool for herpesvirus-induced keratitis, which is a leading cause of blindness and disability. Experimental keratitis produced in rabbits by infection with herpesvirus isolated from a human periorbital lesion was treated with proflavine and light. The herpetic keratitis could be rapidly resolved by the dye-light treatment, whereas improvement was not seen in untreated rabbits, nor in those treated with light alone or dye alone.

Acridines↗
PubMed1972

Production of potent anti-Australia antigen sera of high specificity and sensitivity in goats.

Potent antisera of high specificity and sensitivity were produced, in goats, to purified Australia antigen (Au). The antigen was prepared by one of three methods: (i) pelleting, low pH treatment, isopycnic centrifugation two times in CsCl, and rate zonal centrifugation in sucrose; (ii) same as procedure i, with the exception of the low pH treatment; or (iii) twice banding in CsCl by using a BXIV batch-type zonal centrifuge rotor with subsequent preparative Pevikon electrophoresis. The goat anti-Au sera contained high levels of precipitating antibody as tested by immunodiffusion in agar gel and discontinuous counterimmunoelectrophoresis (DCIE) as well as specific complement-fixing antibody and could be used for routine screening of sera for Au without prior adsorption with Au-negative normal human serum (NHS). Identification of 66 of 70 positive specimens (94.3%) in a panel of 98 coded sera (49 duplicates) with 100% reproducibility was made by using one of the goat anti-Au sera at a dilution of 1:16 in the DCIE method. No false positives were recorded. Low levels of antibody against NHS components were effectively removed by a single adsorption with glutaraldehyde cross-linked NHS.

Adsorption↗