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Biomedical subjects

D H Roberts

Publications and source records attributed to D H Roberts.

At least 91 records · Page 5Linked to original sources
PubMed1978

Studies on bovine leukosis as it is seen in England and Wales.

A random series of 14 clinical cases of bovine leukosis as it is seen in England and Wales has been studied clinically, haematologically, serologically (by the indirect fluorescent antibody test and later by agar gel immunodiffusion as well), virologically (for evidence of bovine leukaemia virus--BLV) and using the electron microsocope to count intranuclear pockets in circulating lymphocytes. Additionally calves have been inoculated with whole blood and a tissue lymphocyte suspension from the first six cases and the experimental calves studied periodically by the same methods. Herds of origin of the field cases were examined for clinical evidence of lymphomatosis, for evidence of leukaemia and for serum antibody to BLV. To date no evidence has been found to indicate that the field cases were other than sporadic and non-contagious. Neither BLV nor specific antibody has been demonstrated; no increase in lymphocytic nuclear pockets has been seen; the transmission tests are still apparently negative. It would appear that sporadic bovine leukosis and enzootic bovine leukosis are aetiologically separate entities.

Animals↗
PubMed1975

Passive immunity to contagious bovine pleuropneumonia.

A significant passive protection against contagious bovine pleuropneumonia (CBPP) was demonstrated in cattle. One group of cattle was inoculated with serum from CBPP-recovered cattle, while another group was inoculated with serum from susceptible cattle. The two groups, along with an untreated control group, were challenged with the virulent Gladysdale strain of Mycoplasma mycoides, using the in-contact method. Four out of the five cattle inoculated with serum from animals which had recovered from CBPP were protected, whereas three of five cattle inoculated with serum from susceptible animals and all the untreated animals died of CBPP.

Animals↗
PubMed1973

Cell-mediated immune response in cattle to Mycoplasma mycoides var. mycoides.

The cell-mediated immune response of cattle to Mycoplasma mycoides var. mycoides was studied. Sensitized lymphocytes in blood leukocyte preparations showed a significant degree of antigen-induced transformation, judged by the uptake of tritiated thymidine. The increase in tritiated thymidine uptake in sensitized lymphocytes in the presence of M. mycoides membrane antigen varied from 2- to 13-fold compared with the controls, and this increase in activity was observed from 3 days after artificial infection. Inhibition of leukocyte migration by M. mycoides membrane antigen commenced between 17 and 30 days after infection, and preliminary observations indicate that this test correlated with the intradermal allergic test. M. mycoides-induced unresponsiveness was demonstrated 23 and 30 days after infection. Unresponsiveness, in that the lymphocytes did not respond to phytohemagglutinin, was very marked in two of three animals and partial in the third animal, whereas the humoral antibody response did not appear to be affected. Antigen-induced transformation was demonstrated in only two out of six cattle vaccinated two months previously with M. mycoides T(1) broth culture vaccine, and óne animal only gave a doubtful intradermal allergic reaction. A further six cattle vaccinated 15 months previously were negative to both the leukocyte migration inhibition test and the intradermal allergic test.

Animals↗
PubMed1971

Interaction of porcine mycoplasmas with fresh animal serum.

When fresh animal serum was dropped onto seeded mycoplasma agar plates, inhibition of growth frequently occurred. This effect was dependent on the mycoplasma serotype and on the animal species from which the fresh serum came. This activity of fresh animal serum was heat-labile and would not diffuse through the agar medium. Growth of all the porcine mycoplasma serotypes was inhibited by fresh sheep serum. M. hyorhinis, M. hyopneumoniae, B 3 and the P 45 strains were insensitive to fresh horse serum. The addition of fresh horse serum to specific M. hyorhinis rabbit antiserum-impregnated disks appeared to have a synergistic effect and the combination of M. hyorhinis antiserum-impregnated disk and fresh horse serum always inhibited the growth of M. hyorhinis strains.

Agar↗