Search PubMed⌕ Search

Biomedical subjects

N J Schmidt

Publications and source records attributed to N J Schmidt.

At least 91 records · Page 5Linked to original sources
PubMed1974

Solid phase radioimmunoassay for identification of Herpesvirus hominis types 1 and 2 from clinical materials.

A solid phase radioimmunoassay (RIA) was developed for typing Herpesvirus hominis (HVH) strains isolated from clinical materials, and it also proved to be applicable to the direct detection and typing of HVH antigen in human and animal brain tissue. The procedure utilized virus-infected human fetal diploid cells or brain tissue smears in the bottom of 1-dram glass vials, antigen was detected through the use of intermediate HVH antisera produced in rabbits or hamsters and cross-absorbed with the HVH heterotype, and (125)I-labeled anti-species (rabbit or hamster) globulins produced in goats were used for detection of immune complexes. The cross-absorbed HVH antisera could be used at high dilutions in the RIA test, and they reacted with marked type-specificity in the RIA system. Specificity of the test was also improved by determining and using optimal concentrations of intermediate sera and of (125)I-labeled anti-species globulins. Results of typing HVH isolates by the RIA procedure agreed in all instances with those obtained by direct fluorescent antibody staining with cross-absorbed conjugates. The RIA procedure was effective and more sensitive than direct fluorescent antibody for demonstrating and typing HVH antigen directly in smears of infected human brain tissue.

Animals↗
PubMed1974

Reactivity of envelope, capsid, and soluble antigens of Herpesvirus hominis types 1 and 2 in the indirect hemagglutination test.

Envelope, capsid, and soluble antigens of Herpesvirus hominis (HVH) types 1 and 2 were compared to crude antigens (disrupted HVH-infected cells) for potency, type-specificity, and diagnostic value in the indirect hemagglutination (IHA) test. The envelope appeared to be the predominant component reacting in the IHA test, but recurrent HVH infections increased the reactivity of human sera with capsid antigens. The soluble antigens reacted in the IHA test with HVH immune animal sera, but very few convalescent-phase human sera showed reactivity with soluble antigens. Overall, none of the subunit antigens showed greater type-specificity than did crude antigens in IHA tests with immune animal or convalescent-phase human sera. Recurrent infections with type 1 or type 2 viruses tended to broaden heterotypic reactivity of the patients' sera with both crude and subunit antigens, even in patients showing only a single type of antibody by IHA inhibition. Subunit antigens were no more sensitive than crude antigens in demonstrating significant IHA antibody titer rises for serodiagnosis of herpesvirus infections, and they generally had to be used at lower working dilutions than crude antigens.

Animals↗
PubMed1973

Association of group B coxsackie viruses with cases of pericarditis, myocarditis, or pleurodynia by demonstration of immunoglobulin M antibody.

Tests for immunoglobulin M (IgM) antibody to group B coxsackieviruses were performed on sera from 259 patients with a clinical diagnosis of pericarditis, myocarditis, or pleurodynia on whom there were no definitive serological or virus isolation findings to establish a viral etiology, and on 259 "control" patients with clinical diagnoses of viral or mycoplasmal pneumonia or pneumonitis. IgM antibodies to coxsackievirus types B1, B3, B4, B5, and B6 were detected by a micro-immunodiffusion technique, and antibodies to virus type B2 were detected by reduction of neutralizing antibodies with ethanethiol. Of the patients with pericarditis, myocarditis, or pleurodynia, 27% (70) had IgM antibody to group B coxsackieviruses, as compared with 8% in the control group. On retrospective review of the clinical diagnosis, some of the patients in the control group with IgM antibody were found to have had additional clinical findings which could be attributed to a coxsackievirus infection. Coxsackievirus IgM antibody was demonstrable in 30% of 113 patients in the study group for whom virus isolation had been attempted with negative results. The presence of coxsackievirus IgM is discussed in relation to the time of serum collection, age of the patients, and month of onset of illness.

Adolescent↗
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

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

Immunofluorescence staining of group B coxsackieviruses.

Studies were conducted on the sensitivity and specificity of indirect fluorescent-antibody (FA) staining for identification of group B coxsackieviruses. Antisera produced in four different species (monkeys, rabbits, horses, hamsters) and immune ascitic fluids prepared in mice were compared for suitability in FA staining. The horse antisera showed high titers of nonspecific staining, and the rabbit antisera showed relatively low homologous FA titers. Immune reagents from monkeys, hamsters, and mice were used for homologous and heterologous testing against cell cultures infected with the various group B coxsackieviruses. Antisera or immune ascitic fluids produced in these three species showed some heterotypic and nonspecific staining at low dilutions, with the monkey antisera showing the highest heterotypic titers. However, the immune reagents could be diluted to a point where they gave no heterotypic reactivity, but still showed characteristic homotypic staining. Heterotypic staining appeared as diffuse, low-level staining of the cells, whereas homotypic staining revealed characteristic, brightly staining aggregates of viral antigen in the cytoplasm of the infected cells. By using hamster immune sera, appropriately diluted to eliminate heterotypic staining and yet give strong homotypic staining, it was possible to identify correctly 79 (93%) of 85 field strains of group B coxsackieviruses at the first passage level in BS-C-1 cells; the remainder of the strains were identified after two passages in BS-CS-1 cells. No incorrect identifications were made. A limited number of field strains of group B coxsackieviruses were passed into rhesus monkey kidney and human fetal diploid kidney cells, and these were all correctly identified by FA staining, even the strains which failed to produce a cytopathic effect in the human fetal diploid kidney cells. Two human heart and brain tissues from which coxsackievirus type B4 had been isolated failed to show homotypic FA staining in excess of nonspecific or heterotypic staining.

Animals↗
PubMed1972

Modified hemagglutination-inhibition test for rubella employing human group O erythrocytes.

A hemagglutination-inhibition (HI) test for rubella is described which utilizes human group O, rather than 1-day-old chick, erythrocytes. The test was found to be as sensitive and reproducible for detection of rubella antibody as HI tests employing chick erythrocytes. Advantages to the use of human erythrocytes are (i) they are more available, (ii) it is unnecessary to absorb natural agglutinins from human test sera, and (iii) heparin-MnCl(2)-treated sera do not agglutinate human erythrocytes, as is sometimes the case with chick erythrocytes. Factors influencing the reliability of the test are discussed.

Agglutination Tests↗
PubMed1972

Occurrence and persistence of "Australia" antigen determinants.

"Australia" (Au) antigens from various groups of individuals were examined for the presence of d and y determinants. Antigens from all of the 214 individuals examined were found to possess either the d or y determinant, in addition to the a determinant. With the ay antiserum employed, antibody absorption was found to be a more effective means than demonstration of spur formation for detection of the y determinant. Antigens with ad specificity predominated in a collection of sera from non-ill Tongan children and adults, but no significant differences were noted in the specificities of antigens from individuals from four different regions. Almost all of the antigens from various groups of individuals in California, including inmates of a state hospital, a group of heroin users, and hepatitis patients from San Francisco General Hospital, were of the ay specificity. With one exception, antigenic specificities were found to persist for 3 years in a group of Tongan school children. Specificities also persisted in chronic carriers from California and in hepatitis patients over the course of antigenemia. Of 15 human and 4 animal antisera examined, antibodies to the y determinant were demonstrable only in a single (human) antiserum, and antibodies to the d determinant were demonstrable in one guinea pig antiserum and one horse antiserum.

Adsorption↗