Biomedical subjects

J M Witkowski

Publications and source records attributed to J M Witkowski.

5 recordsLinked to original sources

PubMed1992

Transmembrane electrical potential of lymphocytes in ageing mice. Flow cytometric analysis of mitogen-stimulated cells.

The changes in transmembrane electrical potential (TMP) of Concanavalin A (Con-A)-stimulated lymphocytes from young adult and aged CBA/Ca mice were studied with a potential-sensitive fluorescent oxonol probe. The initial effect of Con-A was to depolarise lymphocytes from young mice and abrogated in the presence of tetraethylammonium chloride (TEA), an inhibitor of K(+)-selective channels. Young and old T lymphocytes both responded to the calcium ionophore A23187 by becoming hyperpolarized, but this occurred more slowly in the old cells. While treated with the ionophore, old B cells appeared to be limited in their ability to depolarize in the presence of high external K+ concentrations, which did not hold for T cells of old animals. One or more defects in the mechanisms of monovalent ion transport across the membrane of old lymphocytes are probably responsible for these differences and may be associated with the known age-related dysfunction of the immune system.

Aging↗

PubMed1991

Influence of age on transmembrane potential and cell surface charge of human peripheral blood lymphocytes estimated with fluorescent probes.

Transmembrane potential (TMP) and surface charge (CSC) of human peripheral blood lymphocytes were estimated in relation to donor's age. Cyanine dye DiOC(6) and fluorescein--coupled poly-L-ornithine EPLO were used as representative fluorescent probes for microfluorimetric determination of relative TMP and CSC values. Significant decrease in cyanine fluorescence was observed in lymphocytes of old people, which was interpreted as relative depolarization of these cells. No such difference was found when surface charges of young and old cells were compared, although some brightly fluorescent, i.e. highly charged cells appeared among the latter.

Adult↗

PubMed1986

Effects of air ions on the membrane Na, K-ATPase activity of L 1210 cells.

The effect of exposure of L 1210 mouse leukemia cells to artificially generated air ions on the activity of membrane Na, K-ATPase in the cells was investigated. The exposure of cells to air ions of both signs gave identical results, i.e. diminution of transport activity of the enzyme, measured by radioactive 86Rb transport into the cell (ouabain-dependent). Passive ouabain-independent transport of Rb+ into the cells remained unchanged in the air ion-treated cells, as did the passive efflux of the radioisotope from preloaded cells. The possible explanation of the phenomena observed is discussed.

Air Ionization↗

PubMed1985

Decrease of lymphocyte (Na+,K+)ATP-ase activity in aged people.

Activity of (Na+,K+)ATP-ase measured by means of influx of 86Rb was compared in lymphocytes from young, middle-age and old people. It was found that the (sensitive to ouabain) activity of (Na+,K+)ATPase was significantly diminished in the lymphocytes from aged subjects.

Adolescent↗

PubMedDate not supplied

Modification of mitogenic response to concanavalin A of lymphocytes from old-aged donors by ion channel blockers.

Mitogenic response of lymphocytes from young and old donors to Concanavalin A in the absence or presence of Na+ channel blocker--saxitoxin--was compared. Effect of Ca++ channel blockers (Verapamil Diltiazem) on mitogenic response of lymphocytes from old subjects was also examined. It was found that the mitogenic response to Concanavalin A of lymphocytes from donors was significantly lower than that of young ones. In the presence of Saxitoxin the enhancement of the response was noticeable in both groups and the mean responses were similar. However, among the old donors, opposite to the young ones, very high and very poor responders were present. Verapamil and Diltiazem caused significant reduction of mitogenic response to Concanavalin A in the group of old donors. These observations suggest a possible effect of ion channel blockers on immunological functions which would have special significance for old organisms.

Adult↗