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Biomedical subjects

L Paczek

Publications and source records attributed to L Paczek.

At least 145 records · Page 8Linked to original sources
PubMed1991

Suppression of beta 2-microglobulin release from lymphocytes by dialysis membranes.

As lymphocytes are one of the main sources of circulating beta 2-microglobulin (beta 2M), the direct effect of different dialysis membranes on beta 2M release from those cells was studied in vitro. Lymphocytes were isolated from 11 long-term haemodialysis patients and nine healthy controls. Cells were cultured on flat sheet membranes made from either Cuprophan, Hemophan, or polyacrylonitrile. Polystyrole petri dishes were used as controls. Beta 2M concentrations in the supernatant were measured after 3 and 7 days of culture by ELISA techniques. Beta 2M release from lymphocytes obtained from uraemic patients was almost identical to the release from healthy subjects. In the presence of all three membranes the release of beta 2M was less than that produced on polystyrole. This held true for lymphocytes isolated from both healthy and uraemic subjects. As for the three membranes the release of beta 2M into the supernatants was statistically the same when the adsorptive capacity of polyacrylonitrile was taken into account. However, there was a tendency for Cuprophan to exert the strongest inhibition, while Hemophan and polyacrylonitrile reduced beta 2M release to a lesser degree. Based on these data it seems that prolonged interaction between dialysis membranes and lymphocytes does lead to a reduction in beta 2M release.

Adult↗
PubMed1991

Cytokine production by monocytes during haemodialysis.

In order to follow the effect of haemodialysis on monocyte function, we measured the release of interleukin-1 beta (Il-1), interleukin-6 (Il-6), and tumour necrosis factor alpha (TNF alpha) from cultured monocytes isolated before and after dialysis. Monocytes obtained from patients before dialysis released smaller amounts of cytokines than cells from healthy controls. The choice of the dialysis membrane had no effect on predialytic monocyte activity. Basal cytokine release after dialysis remained virtually unchanged, irrespective of the membrane material used. When stimulated with LPS, cells significantly produced more cytokines than under basal conditions. Stimulated monocytes isolated before dialysis produced considerably more cytokines than cells obtained at the end of the dialysis. Taken together, uraemia by itself seemed to depress monocyte activity. Haemodialysis either with cuprophan or PMMA dialysers had no influence on basal cytokine release during a 24-h period following dialysis. Uraemic monocytes, however, appeared to be primed, since stimulation with LPS in vitro caused a more pronounced release of cytokines than in healthy volunteers.

Aged↗
PubMed1990

Dialysis membranes inhibit in vitro release of beta-2-microglobulin from human lymphocytes.

In the present study the effect of different dialysis membrane materials on in vitro beta 2-microglobulin (beta 2M) release by human lymphocytes was investigated. Lymphocytes were isolated from 11 long-term haemodialysis patients and 9 healthy controls. Cells were cultured either on flat sheet membranes made from Cuprophan, Hemophan and polyacrylonitrile or on polystyrol. beta 2M concentrations in the supernatant were measured at 3 and 7 days of culture, respectively. The beta 2M release from lymphocytes obtained from uraemic patients was almost identical with the release from healthy subjects. In the presence of all three membranes the release of beta 2M was less of what was produced on polystyrol. This held true for lymphocytes isolated from both healthy and uraemic subjects. As for the three membrane materials, the release of beta 2M into the supernatants was statistically not different when the adsorptive capacity of polyacrylonitrile was taken into account. However, there was a tendency for Cuprophan to exert the strongest inhibition, while Hemophan and polyacrylonitrile reduced beta 2M release to a lesser degree. Based on these data it seems that the increase in serum beta 2M which has been observed during dialysis with Cuprophan membranes is not caused by direct interaction of lymphocytes with Cuprophan membranes.

Acrylic Resins↗
PubMed1989

TFX modulates the immunosuppressive effect of cyclophosphamide on antibody production in mice.

This study is a continuation of our previous work demonstrating the potentiating activity of TFX on cyclophosphamide-induced immunosuppression. Mice primed with TFX subsequently received cyclophosphamide and antigen and their B cell responses were evaluated with an aid of antigen-specific and reverse plaque forming cell assay. Cyclophosphamide-dependent inhibition of immunoglobulin synthesis was significantly stronger in mice pretreated with TFX than in controls. However, the synergistic immunosuppressive action of TFX with cyclophosphamide was evident only when polyclonal but not specific humoral response was studied.

Animals↗
PubMed1987

Graft-induced polyclonal activation of B cells. I. Alloantigen-induced humoral response in mice.

In recent years evidence has accumulated pointing out that graft rejection may be mediated not only by cellular but also humoral mechanisms. To study this problem in some detail, humoral responses were studied in mice subjected to skin grafting across the H-2 locus. B cell reactivity was measured during the first and second set reactions on consecutive days after transplantation until graft rejection. In vitro B cell activity was assessed by means of the reverse plaque-forming cell assay (PFC) using cells obtained from the lymph nodes and spleens. The results indicate that polyclonal activation of B cells is an integral part of the immune response to skin transplantation in mice. However, no correlation was found between the level of activation as demonstrated by the PFC and the time of graft rejection.

Animals↗
PubMed1987

Graft-induced polyclonal activation of B cells. II. Humoral response of renal allograft recipients (RAR).

Ig production by peripheral blood lymphocytes of renal allograft recipients was studied. It was demonstrated that lymphocytes of patients with acute graft rejection produce elevated numbers of PFC in culture in response to PWM (a T-cell dependent stimulus) and Salmonella paratyphi B (a T-cell independent stimulus) as well as spontaneously. PFC responses were significantly higher in patients with acute rejection than in a group of patients with stable graft function. The B cells of the recipients with stable graft function showed a normal humoral response in vitro. During chronic rejection no significant changes were found in the production of antibodies by B cells.

Adult↗
PubMed1983

The effect of azathioprine on terminal differentiation of human B lymphocytes.

The effect of azathioprine on the terminal differentiation of human B cells triggered in vitro by pokeweed mitogen and S. aureus Cowan I bacteria was studied. AZ caused an enhancement of Ig synthesis in its lower concentrations, a phenomenon dependent on the inactivation of suppressor T cells. Higher drug concentrations impaired T-helper function as well as B cell differentiation of peripheral blood, lymph node, and spleen lymphocytes.

Adolescent↗
PubMed1983

Dual effect of transplantation immunity on lymphocyte and granulocyte progenitors.

Bone marrow, regional lymph node, and spleen myelo- and lymphopoiesis in vitro were studied in mice subjected to skin grafting across the H-2 barrier. It was demonstrated that during the early days posttransplantation there was an enhancement of myeloid and B and T lymphoid colony formation in agar, whereas at approximately the time of graft rejection a strong inhibition of colony growth was observed. These phenomena were regularly observed using bone marrow and lymph node but were not as apparent with spleen cells. Likewise, colony-stimulating factor production by spleen and lymph node cells was increased initially but later when rejection occurred reached levels lower than those of syngeneic control animals, although PGE2 production was increased at the time of rejection.

Animals↗