Biomedical subjects

N M Burdash

Publications and source records attributed to N M Burdash.

44 records · Page 3Linked to original sources

PubMedDate not supplied

Immunologic parameters in Down's syndrome.

Down's syndrome children are known to have increased susceptibility to respiratory infections. Quantitative or qualitative differences in the various components of the immune system could account for increased susceptibility to infection involving the upper respiratory tract. In an effort to establish certain normal values and to determine if humoral immune abnormalities are associated with the chromosomal anomalies of Down's syndrome, immunoglobulin levels, certain complement component levels, viral antibodies, hepatitis B surface antigen and milk precipitins from a population of inpatients and outpatients were compared with those of age, sex and race matched control populations. It does not appear that the upper respiratory infections are associated with abnormally low levels of immunoglobulins or complement, with the possible exception of IgM. Both the inpatient and outpatient Down's syndrome populations had decreased levels of IgM, indicating a possible relationship with the syndrome itself. In addition, the symptomatology does not seem to be due to IgE mediated atopic sensitivity. Hepatitis B surface antigen was found only in institutionalized Down's syndrome patients, but it did not seem to be related to the other immune components studied.

Adolescent↗

PubMedDate not supplied

MIF-like activity in non-stimulated and virus infected cell cultures.

Macrophage-migration inhibition factor (MIF) is a lymphocyte-derived substance which plays an important role in cell mediated immunity. Soluble factors containing MIF-like activity and produced by non-stimulated and virus-infected non-lymphoid cell cultures have also been reported. In the present study, a MIF-like factor was repeatedly detected in Buffalo green monkey kidney cells infected with mumps and herpes simplex virus type 1 (HSV-1) indicating that this substance is reproducible and can be stimulated by two viruses of widely varying groups. Wistar-38 (WI-38) cell cultures also increased production of this substance in response to mumps but not HSV-1 infection, indicating that the production of this factor is not necessarily induced by all viruses. A factor which stimulated the spread of macrophages was also found to be induced in WI-38 cells by both viruses, suggesting yet another substance produced by non-lymphoid cells in response to viral infection. The ability of non-stimulated WI-38 cells to produce MIF-like activity was also confirmed, and this factor could be further stimulated or opposed by viral infection.

Cells, Cultured↗

PubMedDate not supplied

Streptococcal antibody tests in rheumatic fever.

Although the incidence of rheumatic fever has declined significantly over the last decade, testing for antibodies to streptococcal extracellular enzymes maintains an important role in differentiating this disease from others with similar characteristics. Detection of antibodies to streptolysin O and DNase-B remain the more popular single antibody tests while the streptozyme test, which detects antibodies to five distinct streptococcal extracellular products, has been increasingly used in recent years as a screening test. Several new procedures detecting antibodies to different somatic antigens have been developed, the most promising of which seem to be anti-Group A carbohydrate tests. Because antibodies to the group A carbohydrate remain for several years in patients with persistent rheumatic valvular disease, this test should aid in the differentiation of rheumatic from non-rheumatic heart disease.

Antibodies, Bacterial↗

PubMedDate not supplied

Detection of group B streptococci by agglutination testing from selective broth cultures.

A rapid technique for the immunological identification of group B streptococci in vaginal swabs is reported. Vaginal swabs obtained from 567 pregnant women at term or during labor were incubated for eight hrs in Todd Hewitt broth containing 15 micrograms per ml nalidixic acid, one microgram per ml polymixin, and 0.1 microgram per ml crystal violet (NPC broth). After streaking the swabs on blood agar plates, both plain broth cultures and their nitrous acid extracted pellets were tested with a commercial latex agglutination reagent. Beta-hemolytic colonies grown on the blood agar plates after overnight incubation were grouped with commercial latex agglutination and coagglutination reagents for reference identification. Sensitivities for the broth culture and nitrous acid techniques were 86.8 percent and 94.7 percent, respectively; specificities were 97.4 percent and 98.7 percent respectively. Nitrous acid extraction of vaginal broth cultures followed by latex agglutination testing can significantly shorten the time needed to detect group B streptococci, resulting in the intrapartum detection of these organisms.

Bacteriological Techniques↗

PubMedDate not supplied

The Crithidia luciliae and Farr assays for the detection of systemic lupus erythematosus.

The specificity and sensitivity of two commercial systems for the detection of anti-native deoxyribonucleic acid (DNA) antibodies in the diagnosis of active systemic lupus erythematosus were evaluated. Sera containing antinuclear antibodies from 64 patients were tested by an indirect immunofluorescent antibody technique employing the protozoan Crithidia luciliae as substrate and immunoradioassay based on the Farr technique. Twenty one patients had active systemic lupus erythematosus, 21 had other collagen vascular diseases, and 22 had miscellaneous non-collagen vascular diseases. The immunofluorescence test was 100 percent specific and 66.7 percent sensitive for systemic lupus erythematosus, whereas the radioimmunoassay was 90.7 percent specific and 80.9 percent sensitive. There was agreement between methods in 57 of the 64 (89.1 percent) sera tested.

Antibodies↗

PubMedDate not supplied

Identification of clinically significant anaerobic bacteria.

By combining the various methodologies for anaerobic bacteriology, a scheme has been developed with four flow charts for the identification of the clinically significant anaerobic organisms. This scheme incorporates the use of gas chromatography and a micromethod biochemical system.

Anaerobiosis↗

PubMedDate not supplied

A quantitative immunofluorescence assay for IgM rheumatoid factor.

A quantitative immunofluorescence assay for IgM rheumatoid factor (RF) has been developed using the FIAX fluorometer. Two hundred and six (206) patient serum samples submitted for RF or antinuclear antibody testing were assayed by the fluorometric method and by the sheep cell slide agglutination test (Rheumaton, Wampole Laboratories) currently used in our clinical laboratory. There was an overall agreement of 95.1% between the 2 methods. The fluorometric RF assay is simple, sensitive, reproducible, and does not suffer from the subjectivity present in slide agglutination tests.

Agglutination Tests↗

PubMedDate not supplied

Evaluation of a bioassay method for serum amikacin concentrations.

The bioassay system from American Diagnostic for amikacin was compared to the same company's radioimmunoassay (RIA) technique used in this hospital. The bioassay is performed by adding serum from a patient to wells cut in agar which have been seeded with a susceptible fast growing microorganism (Enterobacter). After incubation of five hours at 37 degrees, the zones of inhibition for four standards are measured and plotted. The amount of amikacin in the serum sample is then determined from the linear graph. Ten replicates of a serum with 8 microgram per ml of amikacin and 10 replicates of a serum with 20 microgram per ml of amikacin were assayed on each of four days. Aliquots of the same samples were assayed in a similar manner by RIA. The coefficients of variation (CVs) of the within run assays by the bioassay and RIA methods for the low amikacin test sample ranged from 4.7 to 7.2 percent and 6.2 to 13.0 percent, respectively. The within run CVs for the high amikacin test sample for the bioassay and RIA methods ranged from 5.2 to 6.9 percent and 5.0 to 13.9 percent, respectively. The day to day and overall CVs for the bioassay and RIA methods for the low amikacin test sample were 1.5 and 5.8 percent and 7.4 and 11.8 percent, respectively. For the high amikacin test sample, they were 0.4 and 6.0 percent and 4.0 and 9.6 percent, respectively. The correlation coefficient for 49 sera from patients on amikacin was 94 percent between the two methods.

Amikacin↗