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Biomedical subjects

N Lahat

Publications and source records attributed to N Lahat.

At least 91 records · Page 5Linked to original sources
PubMed1987

Monocyte produced burst-promoting activity after stimulation with lymphokine.

Normal monocytes were stimulated by lymphokine(s) from a homogenous population of malignant T cells of the helper phenotype (OKT 3+/4+/6-/8-/11+). The resultant monocyte-conditioned medium after stimulation with T cell-conditioned medium (M-CM+) was assayed for burst-promoting activity. The number of burst-forming units-erythriod (BFU-E) in methylcellulose cultures of normal human nonadherent peripheral blood cells increased by nearly threefold in the presence of 5% M-CM+. This activity was lost after the conditioned medium was boiled for 20 min. The addition of 5% conditioned medium (CM) from unstimulated monocytes did not significantly increase BFU-E proliferation. We conclude that lymphokine(s) from malignant T cells of the helper phenotype stimulate normal monocytes to produce a heat-sensitive monokine that increases BFU-E proliferation.

Colony-Forming Units Assay↗
PubMed1986

Autologous mixed lymphocyte reaction in multiple myeloma patients: effect of adherent mononuclear cells and T lymphocytes.

Autologous mixed lymphocyte reaction (AMLR) was measured in 12 patients with multiple myeloma. In ten patients depressed AMLR was found. Depletion of adherent monocytes caused enhancement of AMLR in those with a normal OKT4/OKT8 ratio. Only after monocyte depletion was a high correlation found between the AMLR values and the absolute number of OKT+4-T lymphocytes in the patients' peripheral blood. There was an inverse correlation between the suppressive effect of adherent monocytes on AMLR and the patients' serum levels of polyclonal IgG and IgM. Defects in both monocytes and OKT+4-T cells might have caused the low AMLR values and perhaps played a role in multiple myeloma immunodeficiency.

Aged↗
PubMed1985

A subpopulation of suppressor cells in Richter's syndrome with both monocytic and T-lymphocytic characteristics.

We evaluated T-lymphocyte functions in the peripheral blood of a patient with B-cell chronic lymphocytic leukemia after transformation to large cell lymphoma (Richter's syndrome). A subpopulation of E-rosette adherent cells were found with T-lymphocytic surface markers (OKT3+/8+/4+), monocytic characteristics (latex ingestion, nonspecific esterase staining), and suppressor activity. In contrast to the patient's nonadherent T-cells, this subpopulation suppressed PHA proliferation of autologous lymphocytes, pokeweed mitogen (PWM)-induced proliferation of normal non-T cells, and a mixed lymphocyte reaction. Further studies are warranted in patients with Richter's syndrome, in order to determine the frequency and significance of our findings.

Cell Adhesion↗
PubMed1985

Cellular immune functions in patients with primary hyperparathyroidism: effects of histamine and cimetidine.

The possibility of a link between parathyroid hyperfunction and cellular immune functions was studied in primary hyperparathyroid (1 degree HP) patients. The effect of cimetidine on lymphocyte functions in 1 degree HP patients and control subjects was also investigated. Histamine-induced suppressor activity of lymphocytes from 1 degree HP patients was significantly greater than that of controls. Cimetidine addition to both normal and 1 degree HP lymphocyte cultures abolished histamine-induced suppression. In vivo administration of cimetidine, while ineffective towards normal lymphocytes, depressed phytohemagglutinin stimulation of 1 degree HP lymphocytes, indicating possible immunological damage caused by this drug, which is frequently used in the treatment of patients with 1 degree HP.

Cimetidine↗
PubMed1985

Monocyte suppressor function in burns: T cell-monocyte interaction in mediating suppression.

Reduced in vitro T cell mitogen-induced transformation, low proportion of T cells and increased proportion of non-T cells were found in blood mononuclear cells of patients with severe burns 3-12 days after the injury. High spontaneous proliferation of non-T cells was observed and could be related mainly to the B cell fraction. Monocytes mediated suppression of mitogen-stimulated T cell proliferation. We further studied the role of monocytes in the enhanced suppressor activity of Con A-activated T cells and found that in this assay system, the patient's T cells mediated suppression in collaboration with monocytes. In vitro, increased suppressor function was probably the result of in vivo stimulation of inhibitory activity ascribed to both monocytes and T cells of patients. Addition of indomethacin to cell cultures markedly reduced suppression of lymphocyte proliferation. Less significant reduction was noted when the patient's T cells were activated in vitro by Con A. Adjuvant treatment of burn patients with indomethacin may play a role in alleviating suppression of immune response in these patients.

Adolescent↗
PubMed1985

Effect of theophylline on the proportion and function of T-suppressor cells in asthmatic children.

T-cell subpopulations and their function were studied in asthmatic children with or without theophylline therapy. A decreased proportion and function of theophylline-sensitive T-suppressor cells was found in fresh peripheral blood of asthmatic children. Following peripheral blood mononuclear cells (PBMC) incubation in theophylline-free medium, the proportion of theophylline-sensitive T-cells in asthmatic children treated with theophylline was elevated to normal values. However, their suppressive effect on control lymphocyte proliferation was unchanged.

Adolescent↗
PubMed1985

L-Thyroxine-induced leukopenia in a patient with Hashimoto's disease: involvement of suppressor-cytotoxic T cells.

A study of in vitro reactivity to L-T4, as assessed by peripheral blood lymphocyte transformation, was carried out in a patient with Hashimoto's disease who developed leukopenia during treatment with L-T4. L-T4 stimulated lymphocyte transformation in this patient. The proliferating cells were of T lineage and further typing demonstrated that they bore the OKT8 antigen. Cell-mediated immune reactions mediated by OKT8+T cells might have caused the leukopenia, although other mechanisms involving cytotoxic antibodies or antibody-dependent cell-mediated cytotoxicity cannot be excluded.

Female↗
PubMed1985

Behçet's disease: clinical and immunological response to immunosuppressive therapy. A case report.

A patient with Behçet's disease had recurrent bilateral uveitis with retinal exudates and visual deterioration while under intermittent corticosteroid treatment. His peripheral blood lymphocytes showed the following abnormalities: low percentage of T cells; low T cell suppressor activity; high spontaneous B cell proliferation; and high response to phytohemagglutinin. Prostaglandin-producing adherent cells were found to have suppressive activity. Chlorambucil induced a clinical and immunological remission.

Adult↗
PubMed1977

The mutual clonal origin of the lymphoplasmocytic and lymphoma cell in alpha-heavy chain disease.

Biosynthetic studies in alpha-heavy chain disease were performed on the gut tumour which was composed mainly of lymphoplasmocytic cells and on the mesenteric lymph node tumour composed mainly of immunoblasts. The gut tumour cells synthesised alpha-heavy chains and secreted them during 2-5 hr culture, whereas the lymph node tumour cells synthesized alpha-heavy chains which were shed into the culture medium only after 20 hr. These chains were shown to be present on the surface of the immunoblastic tumour cells by enzymatic radioiodination. Both the surface and the secreted alpha-heavy chain of the lymph node and gut tumour were found to be smaller than the alpha-heavy chain of myeloma proteins. These results suggest that the lymphoblasmocytic and the immunoblastic tumour cells originate from the same defective clone.

Adult↗
PubMed1977

Ferritin on the surface of lymphocytes in Hodgkin's disease patients. A possible blocking substance removed by levamisole.

Enzymatic radioiodination of surface proteins of Hodgkin's disease peripheral blood mononuclear cells revealed the presence of a blocking protein on their surface. This protein shed into the medium after incubation with levamisole, which resulted in the unmasking of surface proteins similar to those on normal monunuclear cells. The blocking substance was identified. It reacted with anti-human spleen ferritin. It had no detectable iron and dissociated into monomeric subunits of 18,000 mol. wt. by reduction and alkylation, and therefore it is most probably apoferritin rather than ferritin.

Apoferritins↗