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Biomedical subjects

D Gemsa

Publications and source records attributed to D Gemsa.

At least 127 records · Page 7Linked to original sources
PubMed1983

Stimulation of prostaglandin E and thromboxane synthesis in macrophages by purified C3b.

Complement cleavage product C3b was examined for its effect on macrophages. Albumin-elicited guinea pig peritoneal macrophages kept in short-term culture were challenged with purified homologous C3b, and release of oxygen and arachidonic acid metabolites was studied. C3b at concentrations ranging from 20 to 80 micrograms/ml induced synthesis of large quantities of the arachidonic acid cyclooxygenation products thromboxane B2 (TXB2) and prostaglandin E (PGE) but failed to trigger an oxidative burst. Our findings link together macrophages, complement, and arachidonate metabolites as major participants in inflammatory responses.

Animals↗
PubMed1982

Production of prostaglandin E and an interleukin-1 like factor by cultured astrocytes and C6 glioma cells.

When treated with lipopolysaccharide (LPS), cultured murine astrocytes released significant amounts of prostaglandin E, which caused an inhibition of the in vitro proliferative response of C3H/HeJ thymocytes to mitogen. In addition, an interleukin 1 (IL 1)-like factor secreted by LPS-treated glia cell cultures and by C6 glioma cells was detected. The characterization of the factor as an IL 1-like mediator is based on the findings that the factor 1) enhances the mitogen-induced thymocyte proliferation, 2) exhibits no interleukin 2 (IL 2) activity, but 3) augments IL 2 production by mitogen-stimulated thymocytes, and 4) has a m.w. between 13,500 and 18,000 when generated in serum-free conditions. These observations suggest that astrocytes may interact with the immune system by elaborating nonspecific factors that modulate lymphocyte proliferation. This property of astrocytes may be important in the generation of specific immune responses in the brain, which is considered to be an immunologically privileged organ as it is anatomically sequestered from the immune system.

Animals↗
PubMed1981

The influence of synovial fluid from patients with rheumatoid arthritis on the proliferation of peripheral blood lymphocytes and the prostanoid release from monocytes.

The present study was designed to characterize leukocytes of patients with rheumatoid arthritis (RA) with regard to proliferation of peripheral blood lymphocytes (PBL) and prostanoid release from circulating monocytes (M phi. Compared to cells of healthy individuals, PBL from RA patients exhibited a reduced mitogenic response to concanavalin A (Con A) which was associated with an increased capacity of circulating M phi to synthesize PGE and thromboxane B2 (TXB2). Addition of synovial fluid exudates of RA patients (RA-SFE) to peripheral blood leucocyte cultures produced three effects: A spontaneous proliferation of normal and RA-PBL, a reduction of the Con A response of normal and RA-PBL, a reduction of the Con A response of normal and RA-PBL, and an enhanced release of PGE and TXB2 from RA-M phi only. To elucidate the cellular origin of these activities, normal and RA-PBL were incubated with supernatants (SNT) os synovial cell cultures from RA patients and patients with non-RA joint diseases. SNT from Con A-stimulated synovial lymphocytes of both RA and control patients induced a spontaneous proliferation of normal and RA-PBL. In contrast, SNT from non-lymphoid adherent synovial cells of RA and control patients reduced the Con A response of normal and RA-PBL but a striking difference was noted in that an enhanced PGE and TXB2 release occurred only from M phi of RA patients.

Arthritis, Rheumatoid↗
PubMed1980

Induction of prostaglandin E release from macrophages by colchicine.

Rat peritoneal macrophages released high amounts of prostaglandin E (PGE) when treated in vitro with 10(-7) to 10(-4) M colchicine. PGE production occurred after a lag period of 4 hr and proceeded at a constant rate for more than 24 hr. Lymphocytes could not be stimulated to PGE release by colchicine. Disaggregation of microtubules appeared to be an essential event, since lumicolchicine was inactive and addition of heavy water (D2O) abolished colchicine-induced PGE formation. Cytochalasin B (5 microgram/ ml) did not interfere with PGE production by colchicine during the initial 12 hr, but thereafter it gave rise to an activity capable of degrading or converting newly synthesized PGE. Although details of the mechanisms by which colchicine in association with disrupted microtubules may induce PGE release remain unclear, these observations suggest that components of the cytoskeleton may efficiently influence the biosynthesis of prostaglandins.

Animals↗