PubMed Health⌕ Search

Biomedical subjects

K Krzystyniak

Publications and source records attributed to K Krzystyniak.

At least 55 records · Page 3Linked to original sources
PubMed1984

Entry of mouse hepatitis virus 3 into cells.

The involvement of lysosomes in infection by mouse hepatitis virus 3 (MHV3) was studied. L cells were infected with MHV3 in the presence of NH4Cl or chloroquine, weak bases which increase the intralysosomal pH and impair lysosomal functions. NH4Cl significantly inhibited virus-induced cytopathic effects and MHV3 replication, but did not prevent the attachment of 3H-labelled virus. No inhibition of MHV3 replication by NH4Cl and chloroquine was observed when lysosomotropic agents were added later than 3 h post-infection, suggesting the direct involvement of lysosomes in release of the viral genome into cytoplasm. These results, together with the lack of antibody-mediated immune lysis of MHV3-infected cells, suggest that MHV3 entered cells by an endocytic pathway (viropexis) followed by internalization into cellular lysosomes.

Ammonium Chloride↗
PubMed1983

Muscarinic acetylcholine receptors of rat lymphocytes.

The muscarinic acetylcholine receptors on rat lymphocytes were determined by [3H]quinuclidinyl benzilate binding studies. Binding of [3H]quinuclidinyl benzilate is rapid (half saturation occurred within 120 s) and highly specific. Muscarinic receptors reveal high lability. The number of receptors on plasma membrane depends on time of incubation as well as on composition of incubation medium. Lymphocytes incubated in nutrient-deficient media lose their surface receptors; enrichment of the medium causes reappearance of the receptors. Appearance of [3H]quinuclidinyl benzilate-binding sites in the incubation medium was under conditions in which binding to lymphocytes was decreased. It is concluded that the number of plasma membrane receptors on rat lymphocytes represents the dynamic steady state in which newly synthesized and degraded receptors are balanced.

Animals↗
PubMed1983

Immunodepression of lymphocyte response in mouse hepatitis virus 3 infection.

Replication of MHV3 in macrophage-depleted T cells and effects of MHV3 infection on mouse lymphocytes were studied in mixed lymphocyte reaction and in mitogen-stimulated cells. In vitro infection of lymphocytes with infectious MHV3 resulted in replication of the virus and marked inhibition of the proliferative response of cells. In mixed lymphocyte cultures, a strong inhibition was obtained when either X-irradiated stimulator cells or responder cells were preinfected with infectious virus. Inactive virus was able, however, to induce a slight inhibition of MLC reaction following treatment of responder cells, but no inhibition was seen when stimulator cells were treated. Since the infection did not visibly affect lymphocyte viability, MHV3 appeared to replicate in lymphocytes without displaying any cytopathic effects comparable to those observed in infected macrophages.

Animals↗
PubMed1981

Early interaction between mouse hepatitis virus 3 and cells.

The interaction between mouse hepatitis virus 3 (MHV3) and cells was studied in order to investigate whether or not early events occurring after infection could be involved in the difference in virus replication seen between mouse strains with different genetic sensitivities to MHV3 infection. Kinetic data showed that MHV3 uptake by both macrophages and L cells was time- and temperature-dependent. In addition, treatment of cells with cytochalasin B or prostaglandin E1, prior to virus infection, resulted in a strong inhibition of sheep red blood cell phagocytosis without any effect on MHV3 uptake. Similar uptake of radiolabelled MHV3 was shown by whole spleen cells, purified T lymphocytes and thymocytes. Furthermore, no difference in 3H-labelled MHV3 uptake was seen between macrophages originating from resistant A/J mice, semi-susceptible (C57Bl/6 x A/J)F1 and susceptible animals. These results indicate, therefore, that genetically related in vivo sensitivity toward MHV3 infection is not related to differential uptake of virus by cells.

Alprostadil↗
PubMed1978

Studies on cyclic AMP-cyclic GMP cooperation and on the influence of acetylcholine, adrenaline and thiols in lymphocyte reactivity.

In rat's lymph node lymphocytes, maximal stimulation of the response after suboptimal doses of PHA (1/2 of the optimal dose), measured by the incorporation of 3H-thymidine, after 10(-6) M acetylcholine and after 10 min interval between PHA and acetylcholine application was obtained. In these experiments inhibition of acetylcholine action by its muscarainic antagonists was not observed. It was shown that exogeneous cAMP as well as other factors, which increase cAMP level in lymphocytes had opposite effects to those, which could be caused by increasing of cGMP. Acetylcholine in optimal concentration (10(-6) M) as well as thiols, did not increase the level of endogeneous cAMP in rat lymphocytes.

Acetylcholine↗
PubMed1978

Studies on the influence of thiols on lymphocytes (T-type lymphocytes) function.

Changes of the oxidation/reduction potential of the coupled -SH/SS low molecular sulfhydryl system in rat lymphocytes were determined after incubation of cells with D-penicillamine, cysteine and cysteine hydrazide, in concentration of thiols which did not disturb the response of the cells to phytohemagglutinin (PHA). Considerable increase of the -SH content in lymphocytes was observed after treatment of the cells with cysteine and cysteine hydrazide. Our findings suggest that the biological effect of thiols used in optimal concentrations and conditions might be coupled with the disturbance of the -SH/SS oxidation/reduction system in cells.

Cell Survival↗
PubMed1978

Studies on the influence of thiols on lymphocytes (T-type lymphocytes) functions.

We described changes in nonprotein sulfhydryl content and in intracellular concentration of cysteine (unbound form) in lymphocytes incubated with cysteine, cysteine hydrazide and D-penicillamine (dimethy lcysteine) in concentrations which do not alter the viability of the cells. Essential differences between the action of cysteine and cysteine hydrazide on one hand, and D-penicillamine on the other, can be observed. The formers cause the argumentation in nonprotein thiols content in lymphocytes, whereas D-penicillamine in a similar concentration does hardly alters the intracellular redox -SH/SS potential of nonprotein thiols within the lymphocytes.

Animals↗
PubMed1978

Influence of the cysteine derivatives on the cell-mediated immunity.

The immunosuppressive action of N,N, S-trimethyl-cysteine, S-methyl-L-cysteine hydrazide hydrochloride and L-cysteine hydrazide on the course of post-adjuvant polyarthritis, graft-versus-host reaction, turpentine oedema and incorporation of 3H-thymidine into spontaneous or PHA stimulated lymphocyte cultures was examined. Inhibition of post-adjuvant polyarthritis and prolongation of skin allograft survival time were observed. L-cysteine hydrazide had shown the most inhibiting action. In vitro, S-methyl-L-cysteine hydrazide hydrochloride decreased and N,N, S-trimethyl-cysteine increased the incorporation of 3H-thymidine into the lymphocyte cultures stimulated by PHA. The obtained results were compared with the action of DL-cysteine hydrochloride.

Animals↗
PubMed1977

The action of cysteine on PHA-stimulation of lymphocytes. I. Influence of DNA synthesis.

The influence of short-time preincubation of rat lymphocytes in solutions of L-cysteine reduced glutathione, and dithiothreitol on PHA stimulation of these cells was studied by measuring incorporation of 3H-thymidine. Thirty-minute preincubation in cysteine solution enhanced PHA-induced incorporation of 3H-thymidine. One-hour incubation caused earlier peak of incorporation by one day; and two-hour incubation distinctly inhibited spontaneous incorporation of 3H-thymidine. Incubation in solutions of glutathione and dithiothreitol had no effect on the course or intensity of 3H-thymidine incorporation. However, constant presence of these compounds in cultures was toxic for lymphocytes.

Animals↗
PubMed1977

The action of cysteine of PHA-stimulation of lymphocytes. II. Influence on incorporation of 3H-uridine and 14C-leucine.

The influence of short-term preincubation and continuous cultivation with L-cysteine hydrochloride on incorporation of 14C-leucine nad 3H-uridine in cultures of PHA-stimulated and unstimulated lymphocytes was studied. Preincubation during 1 and 2 hours in presence of cysteine inhibited incorporation of these compounds during the first few days of incubation. After 2-hr preincubation, incorporation was first somewhat depressed and then markedly enhanced. Continual presence of cysteine in the medium markedly inhibited incorporation of 3H-uridine and 14C-leucine from the first to last day of incubation.

Animals↗
PubMed1976

Interaction of 6,6'-dithiodinicotinic acid with rat thymocytes pretreated with thiol compounds.

The number of sulfhydryl groups in the membranes of rat thymocytes were determined, expressed in terms of concentration of 6-mercaptonicotinic acid produced by reduction of 6,6'-dithiodinicotinic acid. The influence of incubation of thymocytes in solutions of L-cysteine, reduced glutathione and dithiothreitol on the number of -SH groups was studied. About twofold higher degree of reduction of 6-6'dithiodinicotinic acid was observed in the reaction with thymocytes incubated previously in 2 mM solution of L-cysteine in comparison with controls. Incubation of thymocytes with dithiothreitol and gluthathione had no effect on the number of -SH groups.

Animals↗
PubMed1976

The action of thiols on lymphocyte membranes.

Short-term incubation with cysteine in concentrations not altering cell viability increased the amount of -SH groups on the surface of rat lymphocytes. Maximal effect was achieved in 10 min using 2 mM cysteine, which concentration also induced immediate total loss of response to adrenaline, as measured by intracellular cyclic AMP level. Neither of these effects was observed after incubation of lymphocytes with glutathione or dithiothreitol.

Animals↗