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Biomedical subjects

R Bergman

Publications and source records attributed to R Bergman.

At least 271 records · Page 15Linked to original sources
PubMed1980

Cell-mediated immune response in pigs persistently infected with a Mycobacterium avium strain.

Following a persistent bacterial infection with a Mycobacterium avium strain in pigs, the lymphocyte stimulation (LS), leucocyte migration inhibition (LMI) and tuberculin skin reactivity responses were studied. The responses in the LS and LMI tests occurred within a period of 35 to 49 days after infection. Positive tuberculin skin responses were found 40 to 70 days after infection. No direct correlation was evident between the LS and LMI tests during the experimental period. The responses to purified protein derivatives (PPD) in the LMI test were of shorter duration than those seen in the LS test. The course of LS in pigs expressed high, lower and non-stimulatory responses to the tested PPDs. At the end of the experimental period, 173 days after infection, lymphocyte stimulatory reactivity to PPDs could be demonstrated in all pigs, whereas a positive tuberculin skin test was observed in only one animal. Lymphocyte responses to M avium PPD were generally higher than were the other tested PPDs.

Animals↗
PubMed1979

Gas chromatographic characterization of porcine and human strains belonging to the Mycobacterium avium-intracellulare complex.

Trifluoroacetylated whole-cell methanolysates of 23 strains designated as belonging to the Mycobacterium avium-intracellulare complex by biochemical, growth chromogenicity and chicken pathogenicity tests, were analysed by gas chromatography. Twenty of the strains were isolated from pigs and the remainder from human beings. Serological typing showed that 13 of the porcine strains, but none of the human strains, belonged to M. avium. The remaining strains, except one which showed autoagglutination, did not react with antisera to M. avium (serotypes 1-3), thus suggesting that they belonged to M. intracellulare. Five different, highly reproducible chromatographic patterns, the main peaks of which were considered as representing bacterial carbohydrates and fatty acids, could be distinguished by visual examination and by cluster analysis. The chromatographic results could not be correlated with those obtained from serotyping of the strains studied. Mycobacteria recovered from different organs of one and the same pig gave virtually identical chromatograms. The strains isolated from three human beings had a chromatographic pattern which was identical with one of those produced by the porcine strains. The present investigation indicates that the gas chromatographic analytic technique used differentiates bacteria within the M. avium-intracellulare complex, without assigning the organisms to species.

Animals↗
PubMed1979

Occurrence and characterization of "avium-like" Mycobacteria isolated from animals in Sweden.

431 cultures of "avium-like" mycobacteria (ALM) were isolated from wild and domestic animals during 1974--76 at the National Veterinary Institute, Stockholm. Of these, 50 isolates from pigs were studied by growth-chromogenicity, pathogenicity, and biochemical tests. Furthermore, thin-layer chromathography was performed, and on some isolates serotyping. All 50 isolates belonged to Runyon's group III and were pathogenic for chicken; none was capable of splitting oleic acid from Tween 80. 47 gave tellurite reduction within a period of three days; one was arylsulphatase-positive after three days and a further four after 14 days. The biological and biochemical tests permit assignation of the 50 isolates to the M. avium-intracellulare complex. The lipid patterns of the isolates examined were analysed by thin-layer chromatography. Thirty-five of the isolates showed a lipid pattern similar to that of A 2 of the fowl reference strain; three belonged to lipid type A 1 and four to A 3. Eight could not be typed. Of 22 isolates, 14 could be assigned to M. avium serotypes.

Animal Population Groups↗
PubMed1978

Parainfluenza-3 virus: difference in capacity of neuraminidase-weak and strong strains to infect young calves and to elicit cellular immune response.

Calves less than four weeks old could not be infected with a neuraminidase-weak strain of parainfluenza-3 virus (Pi3) but were successfully infected with either of two neuraminidase-strong strains. The criteria for infection were virus excretion, cell-mediated and antibody-mediated immune responses. In the lymphocyte stimulation test, calves infected with the neuraminidase-strong Pi3 strain Tüb-E6 responded more strongly to antigen prepared from this strain than to antigen from the heterologous Pi3 strain Um-23. The non-immunoglobulin haemagglutination inhibition activity of the liquid phase of nasal secretions of newborn calves decreased after treatment with Vibrio cholerae neuraminidase. For virus-bound neuraminidase the liquid phase from newborn calves was a richer substrate than the liquid phase from older animals.

Animals↗