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Biomedical subjects

B M Jones

Publications and source records attributed to B M Jones.

At least 235 records · Page 13Linked to original sources
PubMed1977

Delayed hypersensitivity to Escherichia coli in the rat--a study of its possible relevance to the pathogenesis of kidney scars.

Rats sensitized to various strains of Escherichia coli (078, O2K13H1, O6K13H1 and O6K2a2cH1) showed cutaneous delayed type hypersensitivity (DTH) reactions after intradermal challenge with the same or a different strain of Esch. coli. Cutaneous DTH was transferred to non-sensitized rats by administration of lymphocytes from sensitized animals. The common antigen(s) responsible for DTH was not identified but DTH reactions were found to be unrelated to the O or K serotype of the Esch. coli strains used. Intrarenal administration of killed Esch. coli to animals showing cutaneous DTH and non-sensitized controls did not produce evidence of DTH reactions of the kidney. Instead it was shown that intrarenal administration of formalin- or heat-killed Esch. coli leads to kidney scarring in both sensitized animals and non-sensitized controls. These scars were comparable in severity, and were similar to those obtained after infection of the kidney with live organisms. It is concluded that DTH reactions do not play a role in the pathogenesis of kidney scarring associated with Esch. coli infection of the rat kidney but that the strains of Esch. coli studied possess a common heat- and formalin-stable nephrotoxic factor which induces kidney scarring.

Animals↗
PubMed1976

On the susceptibility of human platelets to aggregation by concanavalin A and the effect of this lectin on their response to ADP.

Concanavalin A aggregated gel-filtered platelets in 0.9% NaCl solution signifying cross-bridging by the lectin. Aggregation of these platelets by concanavalin A was temperature dependent; it did not occur at 0-4 degrees C unless the platelets were previously trypsinized. The level of aggregation of trypsinized platelets by concanavalin A at 0-4 degrees C was similar to that of untreated platelets at 37 degrees C. It is suggested that trypsin facilitates platelet aggregation by concanavalin A at 0-4 degrees C by causing a configurational change in membrane glycoproteins which orientates concanavalin A receptor sites into positions that favour lectin cross-bridging. Concanavalin A failed to aggregate platelets in plasma. Radioisotope studies showed that the amount of [3H]concanavalin A which combined with platelets in plasma was extremely low compared with gel-filtered platelets in saline. The aggregation of Ehrlich ascites cells by concanavalin A was considerably reduced when platelet-free plasma was added to the medium suggesting that it was due to the presence of concanavalin A-reactive components in the plasma. Concanavalin A inhibited the ADP-induced aggregation of platelets suspended in plasma or in a salts solution supplemented with calcium and fibrinogen, although the inhibitory effect was more conspicuous in the latter case. The results suggests that concanavalin A produces its inhibitory effect on ADP-induced platelet aggregation by interacting with membrane glycoproteins, and this further suggests their involvement in aggregation.

Adenosine Diphosphate↗
PubMed1976

Specific binding of anti-myosin and -actin gamma-globulins to the surface of trypsin-dissociated embryonic chick cells.

125I-labelled sheep anti-rabbit gamma-globulin antibodies were used to locate rabbit antibodies to smooth- and striated-muscle actomyosins at the surface of trypsin-dissociated embryonic chick cells. Statistical analysis of electron microscope autoradiographs revealed that the plasma membrane of these cells was significantly labelled with both antibodies. Further tests revealed that there were a significantly greater number of antigenic sites present on the cell surface for the gizzard smooth-muscle antibodies than for those against pectoralis straited-muscle actomyosin. It was further shown that both the rate and extent of binding of the 125I-labelled smooth-muscle actomyosin antibodies to the cells were greater than for anti-straited-muscle gamma-globulins. Binding of the former was reduced to a level similar to that of 125I-NIS conjugate by preincubation of the gamma-globulins with smooth-muscle heavy meromyosin, while a simiar reduction was observed when anti-pectoralis actomyosin was treated with actin. It was concluded that actin- and myosin-like proteins must now be considered as integral components of the plasma membrane.

Actins↗
PubMed1976

Increased upper airway resistance in patients with airway narrowing.

The mean air flow resistance of the orolaryngeal (upper) airway was significantly increased in 7 of 11 patients with chronic airway obstruction, when compared with 6 controls. All the patients had noisy respiration with harsh breath sounds audible by auscultation over the larynx. The increase in resistance was greater during expiration than during inspiration. Since 4 patients had normal upper airway resistance, the signs were not invariably associated with upper airway narrowing and presumably could arise also in the chest. When increased, upper airway resistance was usually more than half the total airway resistance. It is suggested that this increase could only be due to narrowing of the glottis, probably by muscle activity. This narrowing may have had the same function as expiration through pursed lips. On the other hand, when present, the increased resistance through the upper airway during inspiration is unlikely to have had a useful function.

Adult↗
PubMed1976

Mechanisms of leucocyte migration inhibition by breast tumour cell fractions.

Leucocyte migration inhibition by autologous breast tumour cell fractions was mediated by a soluble factor synthesized and released by mononuclear leucocytes and active against migrating granulocytes. This mechanism is similar to that previously described in respect to cell-mediated sensitivity to microbial antigens. Alternative mechanisms involving directly reactive granulocytes or cytophilic antibodies were rarely operative in the migration tests.

Antibodies, Neoplasm↗
PubMed1976

Shape changes and reduced calcium level in the surface membrane region of human platelets exposed to manganese in vitro.

The effect of exogenous manganese ions upon human platelets in vitro has been studied. Morphological changes reported include the loss of discoid shape, increase in filopodia and close apposition of platelet surfaces. Electron microscope X-ray microanalysis of thin-sectioned material revealed a significant decrease in the bound calcium levels of the surface membrane as a result of manganese treatment. Analysis of whole platelet homogenates using atomic absorption spectrophotometry indicated that the total internal platelet calcium content had increased significantly. It is suggested that manganese induces the observed changes by displacing calcium from the regulatory system of an actomyosin-like protein complex at the periphery of the platelet.

Blood Platelets↗
PubMed1975

Horizontal studies of cell mediated immune reactions to autologous tumour antigens in patients with operable mammary carcinoma.

The leucocyte migration and guinea-pig macrophage migration procedures were used to assess cell mediated, tumour directed immune reactions in patients with mammary carcinoma undergoing simple mastectomy with or without post-operative irradiation. Forty-seven per cent of patients reacted to autologous tumour antigens and 40% to allogeneic antigens when tested 7 days after operation; 23% reacted to autologous antigens at 2 months, 19% at 6 months and 34% at 1 year after surgery. Reactions to benign tissue fractions were rare. Better discrimination between test and control subjects was obtained when 3000 g sediments rather than nuclei-depleted homogenates (extracts) were used. Irradiation 3-7 weeks post-operatively did not depress the in vitro response at 2 months and yielded a higher rate of positive reactions at 6 months. Correlations of serial LMT responses with certain clinical findings are discussed.

Antigens, Neoplasm↗
PubMed1975

An automated immunoradiometric assay for ferritin.

A semi-automated method for the immunoradiometric assay of ferritin has been developed. Results obtained with serum samples show excellent correlation between this method and the previously described assay. A further useful reduction in the assay time may be achieved by incubating for 3 hours at 37 degrees C instead of 24 hours at 4 degrees C.

Ferritins↗