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Biomedical subjects

J Nowak

Publications and source records attributed to J Nowak.

At least 181 records · Page 10Linked to original sources
PubMed1979

T and B lymphocytes in the ontogenetic development of man.

Cord blood lymphocytes of premature and mature fetuses and peripheral blood of infants and adults were studied by rosette techniques and membrane immunofluorescence. Percentage of lymphocytes carrying surface immunoglobulins, receptors for complement and receptors for uncoated sheep erythrocytes or receptors for Fc IgG was determined. T lymphocyte receptors were found to appear later in ontogeny than the receptors typical of B lymphocytes. Receptors for Fc IgG were the earliest to appear: already in premature fetuses the percentage of lymphocytes resembled the one seen in healthy adults. However, the absolute number of T cells increased during development of fetuses and infants and slightly decreased in adults. On the other hand, the absolute number of B lymphocytes were highest in mature fetuses and decreased in subsequent age groups. In the course of human ontogeny a progressive increase was found in lymphocytes carrying full sets of T or B lymphocyte receptors, paralleled by a corresponding decrease in mean values of "null" lymphocytes free of detectable receptors.

Adolescent↗
PubMed1978

Effect of exercise on human arterial and regional venous plasma concentrations of prostaglandin E.

Healthy male volunteers underwent catheterization of a brachial artery and subclavian, hepatic, renal, and femoral veins. Blood was sampled simultaneously from all catheters, at rest as well as during supine leg exercise at 130 W. Plasma PGE were extracted and purified, using silicic acid chromatography, and subsequently quantified, using RIA. At rest no release or uptake of PGE was observed in the arm, the splanchnic region, or the leg, but in the kidney an uptake was noted. During exercise a significant release of PGE developed in the arm and in the leg. The data support the hypothesis that vascular PGs play a role in the local adaptation of the circulatory system to exercise.

Adult↗
PubMed1978

Influence of indomethacin and of prostaglandin E1 on total and regional blood flow in man.

The central and regional circulatory effects in man of the prostaglandin synthetase inhibitor indomethacin and of prostaglandin E1 (PGE1) were studied. Systemic blood pressure, cardiac output, and renal and splanchnic blood flow were measured at rest, following infusion of indomethacin (50 mg i.v.), and during infusion of PGE1 (4--8 mg x min-1 i.v.) after the administration of indomethacin. An increase in the total systemic resistance (+ 20%), as well as in the renal (+ 30%) and splanchnic (+ 16%) vascular resistances developed rapidly following the administration of indomethacin. Infusion of PGE1 completely restored the resistance in the renal and splanchnic regions, and in addition markedly increased the blood flow in non-visceral tissues. We suggest that the circulatory effects by indomethacin are elicited via the drug's inhibitory effect on prostaglandin synthetase in the vessel walls, and that vasodilating products of PG synthetase affect the regional blood flow distribution in man.

Adult↗
PubMed1976

Effects of inhibitors of DNA, RNA and protein synthesis on frequencies and types of premature chromosome condensation from X-ray induced micronuclei.

Cells containing X-ray induced micronuclei were treated for a few hours before fixation with inhibitors of DNA synthesis (cytosine arabinoside; azathioprine; thymidine; trenimon), of RNA synthesis (actinomycin D; ethidium bromide), and of protein synthesis (puromycin). Only the inhibitors of DNA synthesis lead to a significant suppression of the frequencies of mitoses with micronucleus derived premature chromosome condensation (PCC). We tend to interprete the result as follows: Micronuclei that are in the G1 phase of their cell cycles are accumulated at the G1/S border or in the early S phase of their cell cycles under the influence of the inhibitors of the DNA synthesis. Micronuclei blocked in this way cannot be induced to undergo PCC and seem to disappear from the cells.

Azathioprine↗