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Biomedical subjects

M I Jayson

Publications and source records attributed to M I Jayson.

At least 145 records · Page 8Linked to original sources

Continuous recording of neck rotation: preliminary observations.

An instrument is described that allows continuous recording of neck rotation for periods of up to 12 hours. This allows analysis of how the neck actually is used rather than its range of positions on static testing. This technique will be helpful in evaluating the severity of disorders of the neck and the effectiveness of treatment.

Electronics↗

Chloroquine: its effect on leucocyte auto- and heterophagocytosis.

The effect of chloroquine on phagocytosis and leucocyte ultrastructure has been examined. Incubation of neutrophils in 50 micrograms/ml chloroquine for 15 minutes produced a significant inhibition of latex particle uptake. After 90 minutes both 50 and 5 micrograms/ml inhibited phagocytosis while 7 of 9 cases were also inhibited at 0.5 micrograms/ml. However, after 4 hours 50 micrograms/ml chloroquine caused neutrophil granule vacuolation and a massive increase in autophagosomes in other cell types. Incubation in 5 to 0.05 micrograms/ml, which includes therapeutic plasma levels, had no effect on neutrophil ultrastructure but produced a dose-related increase in the number of lymphocytes containing autophagosomes, reflecting altered lysosomal function. As the antimalarial effect of chloroquine is manifested by giant autophagosome formation in Plasmodium, a common antirheumatic and antimalarial mechanism of action is postulated.

Autophagy↗

The presence of abnormal lysosomes in lymphocytes and neutrophils during chloroquine therapy: a quantitative ultrastructural study.

Lysosomal ultrastructure in circulating lymphocytes and neutrophils from the blood of 22 patients with rheumatoid arthritis or systemic lupus erythematosus undergoing chloroquine therapy has been examined and compared with that of rheumatoid cases receiving alternative forms of treatment and non-rheumatoid controls. The lymphocytes of all 22 patients receiving chloroquine showed a highly significant number of lamellar inclusion bodies (mean 9.3%) compared with only occasional inclusions in six of the 14 rheumatoid and four of the 12 non-rheumatoid controls (means 0.86% and 0.83% respectively). Neutrophils from eight chloroquine-treated patients also showed abnormal granules which were absent from both control groups. These findings confirm our earlier in vitro work which indicated that lymphocytes, compared with neutrophils, had a greater susceptibility to chloroquine action with respect to alterations in lysosomal structure.

Arthritis, Rheumatoid↗

Starch synovitis.

Three patients with unexplained synovial inflammation were found to have an ulcerative, granulomatous synovitis on biopsy. Maize starch was identified in giant cells within the granulomata. Starch synovitis has clinical and histological similarities to starch peritonitis, which is thought to be an example of a cell mediated immune response.

Adult↗

Problems for rheumatic patients in opening dispensed drug containers.

The ability of 50 rheumatoid arthritis patients with hand involvement and 50 normal control subjects to open a range of reclosable tablet containers and unit dose packs was tested. Child-resistant containers, particularly the clic-loc type, proved the most difficult for patients and control subjects to open. Smaller containers were less easy to open than comparable ones of a larger size. Only 54% patients were able to remove a suppository from its wrapping. Blister packs and conventional screw-capped tablet bottles were easiest to open. Dispensing of drugs for rheumatic patients in child-resistant containers should be limited to those without hand involvement.

Activities of Daily Living↗

Compression stresses in the posterior elements and pathologic consequences.

Pathologic, experimental, and clinical studies indicate that excessive strain concentration may occur in the posterior elements of the spine and be increased by extension. They may cause small fractures in this region and can be responsible for episodes of back pain. The diagnosis is usually missed.

Adult↗

Inhibition of lymphocyte activation by gold sodium thiomalate.

Activation of lymphoid cells by both T and B cell mitogens was inhibited by gold sodium thiomalate (GST). The action of GST did not appear to be exerted at early stages of lymphocyte activation. Inhibition by GST was sustained throughout 4 days of culture. The inhibitory effect of GST was reduced at low serum concentrations. Sodium thiomalate and sodium chloroaurate were also able to inhibit lymphocyte activation.

Animals↗

Prednisolone inhibits phagocytosis by polymorphonuclear leucocytes via steroid receptor mediated events.

Prednisolone, at concentrations between 2.78 x 10(-6) M (1 mug/ml) and 1.39 x 10(-8) M (5 x 10(-3) mug/ml) exerts an inhibitory effect on the phagocytosis of latex particles by normal human polymorphonuclear leucocytes in vitro as assessed by electron microscopical analysis. This inhibition appears to be receptor-mediated, as it is dependent upon RNA and protein synthesis and is glucocorticoid specific.

Cycloheximide↗

The clinical significance of pain threshold measurements.

Pain is an experience common to us all. There are various methods of attempting to measure pain in an individual. Pain threshold would appear to be the most useful of these as it is atraumatic and repeatable over long periods in healthy individuals. Various factors affect pain threshold such as anxiety. There are a number of ways of measuring pain threshold the requirement for these being similar, for example producing no tissue damage. Pain threshold appears to change in various clinical conditions such as osteoarthrosis of the hip once the painful condition is relieved the threshold may revert back to normal. Other painful conditions such as rheumatiod arthritis do not appear to alter the pain threshold. Pain threshold does not appear to be altered by analgesic drugs, however other drugs may alter the pain threshold.

Age Factors↗

Extractable proteoglycan from human femoral-head articular cartilage.

Proteoglycans were prepared from human femoral-head articular cartilage by using either guanidinium hydrochloride or MgCl2 as extractant, followed by density-gradient centrifugation. The proteoglycan subunit had a particle weight of 2.6 x 10(6), with a radius of gyration, RG, of 68.5 nm in 150 mM-NaCl/20 mM-sodium phosphate buffer, pH 7.0. The proteoglycan aggregate had a particle weight of 3.7 x 10(6) (RG 84 nm) for guanidinium hydrochloride extracts and 8.7 x 10(6) (RG 118 nm) for MgCl2 extracts in the same buffer. The addition of excess of high-molecular-weight hyaluronate did not significantly alter the particle size of the aggregate. The small increase in size probably reflects a rapid equilibrium between hyaluronate and proteoglycan monomers, and is not due to proteolytic cleavage producing non-aggregating units. Experiments that support the rapid-interaction hypothesis include analytical ultracentrifugation and column chromatography. This interaction does not appear to be pressure-sensitive at 20 degrees C, but is sensitive to temperature variation near the physiological range.

Adolescent↗

Effect of inflammatory arthritis on dexamethasone receptors in phagocytes--a possible role for plasma factors.

Synovial tissue cells from patients with seropositive rheumatoid arthritis bind dexamethasone in a similar fashion to the classical steroid receptors on other cells. In contrast, synovial fluid cells and blood PMNLs from these patients bind dexamethasone with much reduced affinity. Some component of plasma may interfere with the binding of dexamethasone to its receptor.

Arthritis, Rheumatoid↗

beta 2-Microglobulin levels in serum and urine of rheumatoid arthritis patients on gold therapy.

The levels of beta 2-microglobulin (beta 2-m) in serum and urine of 24 seropositive patients with rheumatoid arthritis (RA) treated with regular gold (sodium aurothiomalate) injections have been investigated. The values obtained were compared with levels from 20 seropositive patients with RA treated only with nonsteroidal anti-inflammatory drugs and 20 age and sex matched normal controls who had received no medication. A significant increase of urinary beta 2-m levels was found in the gold-treated RA group. No correlation between dose of gold received and the levels of beta 2-m in the urine could be established. There was also no correlation between the erythrocyte sedimentation rate (ESR) or total lymphocyte count and beta 2-m levels in serum or urine. We conclude that serum and urinary beta 2-m levels appear to be poor indices of joint inflammation, but sequential urinary beta 2-m levels may prove valuable in monitoring the development of renal tubular lesions due to gold therapy.

Adult↗