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Biomedical subjects

S Peller

Publications and source records attributed to S Peller.

At least 37 records · Page 2Linked to original sources
PubMed1988

Effect of levamisole on chemotaxis of granulocytes from uremic patients.

Uremic granulocyte chemotaxis was assessed in the presence of four different concentrations of levamisole. Chemotactic responsiveness of uremic granulocytes was significantly decreased compared to normal, both in the absence of levamisole and with all levamisole concentrations tested. However, with 10(-3) and 10(-4) M levamisole concentrations, uremic granulocyte chemotaxis was similar to that of normal granulocytes without levamisole. Defective chemotactic activity of granulocytes may play a role in the increased susceptibility of uremic patients to infections. Pharmacological correction of this defect may improve the patients' ability to cope with infections.

Adult↗
PubMed1988

1,25-Dihydroxyvitamin D-induced suppressor cells in uremic versus normal lymphocytes.

1,25-Dihydroxyvitamin D3 (DHD) has been shown to suppress mitogen-induced blast transformation. This inhibition is abolished by prior elimination of adherent cells. Chronic renal failure is an immunodeficiency state on the one hand and is associated with abnormalities in vitamin D metabolism on the other. The effect of DHD on the induction of suppressor cells in uremic vs. normal peripheral blood mononuclear cells was investigated. Study groups included 16 chronically uremic patients and 16 age- and sex-matched controls. DHD induced suppressor cell activity in normal lymphocytes. However, no suppressor cell activity was observed in lymphocytes from the uremic patients preincubated with DHD. The origin of the responder cells (normal or uremic) did not affect the outcome. The results would suggest that monocyte-adherent suppressor cells from uremic subjects are either incapable of binding DHD or fail to mount a normal post-receptor intracellular chain of events culminating in suppressor activity.

Adult↗
PubMed1986

Induction of suppressor cells in normal lymphocytes by uremic serum.

Sera of patients on chronic hemodialysis induced suppressor cell activity (SCA) in normal peripheral blood mononuclear cells, which significantly impaired blastogenic response to PHA. This SCA is statistically not different from Con A induced SCA. Both SCAs are however additive. Speculations concerning the modes of action of this induced SCA are discussed.

Adult↗
PubMed1986

Immunoregulatory defect in patients with autoimmune thrombocytopenic purpura (ATP).

Con A-induced suppressor cells were studied in 20 patients with autoimmune thrombocytopenic purpura and 20 normal controls. Percentage of suppression was determined on autologous and allogenic lymphocytes during blast transformation with phytohemagglutinin (PHA). In 10 patients and 10 controls helper (T4) and suppressor (T8) subsets were also determined, using monoclonal antibodies. We found a significant decrease in patients' suppressor cell activity both with autologous and allogeneic lymphocytes. Patients' responder lymphocytes were also impaired when tested with normal suppressor cells. The numbers of T4 and T8 in patients was found to be normal although the ratio T4/T8 was somewhat lower than in normal controls. There was a significant direct correlation between the numbers of T4 of patients and their suppressor cell activity on allogeneic lymphocytes suggesting an immunoregulatory defect at the level of induction of suppressor cells.

Adolescent↗
PubMed1986

The effects of uremic serum and 3'-5' cyclic AMP on blastogenesis of normal lymphocytes.

Phytohemagglutinin (PHA) induced lymphocyte blast transformation is impaired both in uremic lymphocytes and in normal lymphocytes exposed to uremic serum. Cyclic AMP is known to inhibit blast transformation in normal and uremic lymphocytes. This investigation was undertaken to assess quantitatively the effects of uremic serum and cyclic AMP on blastogenesis of normal lymphocytes. Uremic serum or cyclic AMP significantly inhibited blast transformation of normal lymphocytes. These effects were statistically similar and cumulative. We conclude that the inhibition imposed by uremic serum on normal lymphocyte blastogenesis is predominantly mediated by a mechanism(s) different from cyclic AMP.

Cells, Cultured↗
PubMed1985

The effect of several uremic parameters on uremic serum inhibition of lymphocyte blastogenesis.

Uremic sera are known to inhibit thymidine incorporation of normal lymphocytes. The nature of the factor(s) responsible for this inhibitory effect has not been completely elucidated. In this study a possible correlation was investigated between a number of uremic blood constituents altered with the progression of the disease and the immunoinhibitory effect of the respective sera. No such correlation was found with the values of hematocrit, urea, creatinine, calcium and phosphorus. On the other hand a significant negative correlation emerged between H+ and Mg2+ ion levels and the inhibition imposed on normal lymphocyte thymidine incorporation. This apparently paradoxical result would indicate that with regard to these two parameters the greater the severity of renal failure the smaller would be the immunoinhibitory effect of the respective serum. The inhibition imposed by uremic serum on immune functions is probably a multifactorial phenomenon, in which H+ and Mg2+ might play a role antagonistic to inhibitory factors.

Adult↗
PubMed1985

Functions of polymorphonuclear (PMN) leukocytes of patients with lymphoproliferative diseases.

PMN leukocytes from untreated patients with multiple myeloma (MM), Hodgkin's disease (HD) and non-Hodgkin lymphoma (NHL) were studied in vitro for their phagocytic and chemotactic function. Alkaline phosphatase score and the reduction of nitroblue tetrazolium (NBT) in these leukocytes were also determined. Most of the functions of PMN leukocytes from untreated patients with MM were impaired, compared to control leukocytes, while those from patients with HD and NHL were impaired only in their chemotactic response to casein and endotoxin-activated serum (EAS).

Adolescent↗
PubMed1982

Modulation of endometrial lymphocyte response in menstrual cycle of fertile women.

Endometrial lymphocytes were isolated in two groups of fertile women, 17 of them normal and seven with various clinical problems. In order to study their immunological properties, endometrial and blood lymphocytes were cultured with either phytohemagglutinin (PHA), concanavalin A (Con A), pokeweed (PW), or purified protein derivative (PPD). Lymphocyte response was assayed by tritiated thymidine incorporation. The percent of T cells was estimated by E-rosette formation. In the normal fertile group, endometrial lymphocyte response to PHA and to Con A was found to correlate with the days of menstrual cycle, rising in a linear fashion between days 9 and 24. In the group with clinical problems, no correlation was noted. In neither group were endometrial lymphocyte responses to PW or PPD or percent of endometrial lymphocyte rosette formation influenced by the menstrual cycle. The modulation of endometrial lymphocyte response to PHA or to Con A stimulation in normal fertile women during the menstrual cycle seems unrelated to the number of T cells.

Adult↗
PubMed1981

Effect of uremic serum on E-rosette formation of normal lymphocytes modulated by levamisole.

The number of E-rosette forming cells of lymphocytes from healthy subjects was determined under various experimental conditions. Sera from 16 chronic hemodialysis patients were incubated with lymphocytes from 16 matched normal subjects. The effect of levamisole on this combination was studied. Uremic serum markedly inhibited E-rosette formation of normal lymphocytes. Pretreatment with levamisole completely prevented this effect, whereas levamisole treatment following incubation with uremic serum resulted in a partial correction of the E-rosette formation. The hypothesis best fitting these results is that a factor present in uremic serum blocks sheep red cell receptors on normal lymphocytes; levamisole, having a greater affinity for these receptors, prevents or partially corrects the effect of the blockade.

Humans↗
PubMed1979

UV-endonuclease from calf thymus with specificity toward pyrimidine dimers in DNA.

We describe the partial purification of an endonuclease from calf thymus that nicks phage PM2 DNA irradiated with UV doses producing only a few pyrimidine dimers per molecule. It has much less activity on DNA that has been subjected to enzymatic photoreactivation after UV irradiation. The calf thymus endonuclease is different from other mammalian UV-endonucleases so far described in that it seems to be dimer specific. The enzyme is stimulated by Mg2+ and is inactive in the presence of EDTA. It binds to UV-irradiated DNA-Sepharose from which it is released by low concentrations of KCl. Gel filtration data indicate that the endonuclease may belong to a high molecular weight protein or protein complex. The enzyme is very labile and freezing increases its lability.

Animals↗