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Biomedical subjects

M Yaron

Publications and source records attributed to M Yaron.

At least 181 records · Page 10Linked to original sources
PubMed1980

Stimulation of prostaglandin E production by bacterial endotoxins in cultured human synovial fibroblasts.

E coli, shigella, salmonella, and cholera endotoxins stimulated prostaglandin E (PGE) production by cultured human synovial and foreskin fibroblasts. The minimal effective dose of Shigella endotoxin was 2 micrograms/ml and a maximal response was observed at 10 micrograms/ml. PGE stimulation was first detected 7 hours after addition of cholera endotoxin. Stimulation by shigella endotoxin of both PGE and hyaluronic acid production was inhibited by indomethacin and aspirin. The present results suggest that PGE is a mediator of joint inflammation induced by endotoxins.

Cells, Cultured↗
PubMed1979

Acute induction of joint inflammation in the rat by poly I . poly C.

Intraarticular injection of interferon inducer, double-stranded polyinosinate-polycytidylate (Poly I . C) caused acute synovitis in rats. This acute inflammatory response was accompanied by an increased concentration of prostaglandin E (PGE) in the synovial tissue. Double-stranded polyadenylate-polyuridylate (Poly A . Poly U) was less potent than Poly I . Poly C in inducing synovitis and increasing PGE concentration, while single-stranded polyinosinate (Poly I) or polycytidylate (Poly C) were inactive in these respects. Intraarticular injection of partially purified mouse fibroblast interferon also induced synovial inflammation. The present results suggest that interferon may be a mediator of viral inflammatory responses.

Animals↗
PubMed1977

Hyaluronic acid production by irradiated human synovial fibroblasts.

Radioactive particles as well as X-irradiation from an external source have been used in the treatment of rheumatoid arthritis, osteoarthritis, and ankylosing spondylitis. In order to clarify effects of ionizing irradiation on synovial cells, radioactive gold (198Au) and yttrium (90Y) were added to fibroblast cultures derived from human synovial membranes. Other cultures were irradiated by a Picker X-ray machine. Fibroblast growth and hyaluronic acid production were measured. Radioactive gold and yttrium particles induced a significant increase of hyaluronic acid synthesis rate (pg/cell/day) and inhibited fibroblast growth. Fibroblasts continued to overproduce hyaluronic acid and to show growth inhibition 3 weeds after irradiation with radioactive gold. Hydrocortisone inhibited hyaluronic acid overproduction induced by radioactive gold. Overproduction of hyaluronic acid induced by the X-ray machine was inhibited by hydrocortisone, actinomycin-D, and cycloheximide. Fibroblasts derived from normal and rheumatoid patients responded similarly to ionizing irradiation.

Fibroblasts↗
PubMed1976

Connective tissue activation: VIII. The effects of temperature studied in vitro.

The effects of increasing environmental temperature were studied in two normal and two rheumatoid human synovial cell cultures. Control cultures showed an increased rate of hyaluronate synthesis and glucolysis as temperature was increased from 30 C to 39 C. Cultures which were activated (stimulated by a connective tissue activating peptide, CTAP) showed an especially striking increase in hyaluronic acid synthesis, glucose uptake and lactate formation at 36 C and 38 C. The data suggest that small changes in joint temperature may be associated with profound alterations in synovial metabolic activity.

Arthritis, Rheumatoid↗