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Biomedical subjects

M J Shaw

Publications and source records attributed to M J Shaw.

At least 55 records · Page 3Linked to original sources
PubMed1987

Preparation of enriched plasma membranes from bovine gallbladder muscularis for characterization of cholecystokinin receptors.

A method for the preparation of enriched plasma membranes from bovine gallbladder muscularis was developed, validated, and applied to the characterization of receptors for the gastrointestinal hormone cholecystokinin (CCK) on this target. Binding of radioiodinated CCK ligands to this preparation was rapid, reversible, temperature-dependent, saturable, and specific. Only structurally related peptides inhibited CCK binding, and good correlation existed between relative potencies for binding inhibition and for stimulating gallbladder contraction. Computer analysis of CCK-binding data using a nonlinear model-fitting program best fit a model with a single class of sites, with Kd 756 pm and binding capacity 4.5 +/- 1.3 pmol/mg of protein. This degree of enrichment for plasma membranes was adequate for the initial biochemical characterization of this CCK receptor. Affinity labeling using 125I-Bolton Hunter-CCK-33 and m-maleimidobenzoyl-N-hydroxysuccinimide ester identified proteins with Mr = 70,000-85,000, Mr = 120,000-125,000, and Mr = 200,000. Labeling was inhibited in a concentration-dependent manner, with an IC50 of 1 nM CCK-8, and the electrophoretic mobility of these bands was not different under reducing and nonreducing conditions. The major labeled band of Mr = 70,000-85,000 has a lower apparent Mr than that of the analogous band in pancreas labeled with similar methods, supporting the molecular heterogeneity of CCK receptors on these two target tissues.

Animals↗
PubMed1985

Clinical and endoscopic findings in patients early in the course of clostridium difficile-associated pseudomembranous colitis.

Endoscopic and clinical features are reported for 39 patients detected early in the course of pseudomembranous colitis. Disease was detected early by virtue of careful surveillance in patients in whom diarrhea developed. Early proctosigmoidoscopic findings in pseudomembranous colitis are illustrated. Clinical presentation includes development of fever, leukocytosis, abdominal pain, and even an ileus picture on radiography in addition to diarrhea.

Adult↗
PubMed1984

Attachment retained overdentures: a report on their maintenance requirements.

Twenty-three patients who received attachment retained overdentures between 1964 and 1977 are reviewed. One third of the patients examined had carious abutment teeth, oral hygiene was poor, and periodontal disease prevalent. Overdentures opposed by natural teeth required more extensive prosthetic maintenance than overdentures opposed by a conventional complete denture. Three quarters of the teeth retaining the prostheses were functioning adequately after a mean period of 7 years.

Adult↗
PubMed1981

Native type II collagen--induced arthritis in the rat: the effect of complement depletion by cobra venom factor.

Antibodies to native bovine type II collagen may be important in initiating arthritis in rats immunized with this antigen. The cross-reactivity of these antibodies with native rat type II collagen was higher in rats that developed arthritis than in those that did not. Depletion of serum C3 levels by cobra venom factor delayed the onset of arthritis until C3 levels were returning to normal; therefore, complement may be involved in initiation of the arthritis, and this arthritis may be an example of an immune complex--mediated disease.

Animals↗
PubMed1981

Incidence and correlation between serum IgG and IgM antibodies to native type II collagen in patients with chronic inflammatory arthritis.

Raised serum IgG and IgM antibody levels to native type II collagen were found in patients with rheumatoid arthritis and in patients with juvenile chronic arthritis. There was a good correlation between the serum IgG and the IgM antibody levels in rheumatoid arthritis and a weaker correlation in juvenile chronic arthritis. Raised serum IgM antibody levels to native type II collagen were found in only 1 patient each with ankylosing spondylitis and psoriatic arthritis, and in these groups here was no correlation between the serum IgG and the IgM antibody levels. The highest serum IgG and IgM antibody levels to native type II collagen were found in rheumatoid arthritis. These results, together with the results on serum antiglobulin levels, indicate that patients with rheumatoid arthritis produce antibodies of both IgG and IgM immunoglobulin class which may have pathogenetic significance in the more severe arthritis found in this condition.

Adolescent↗
PubMed1980

Incidence of serum antibodies to native type I and type II collagens in patients with inflammatory arthritis.

Using a new solid-phase double-antibody radioimmunoassay we have determined the incidence of serum IgG antibodies to native bovine type I and type II collagens in patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS), and psoriatic arthritis. Raised serum IgG antibody levels to native type I collagen were present in 49% of patients with RA, 30% with AS, and none of the patients with psoriatic arthritis. Raised serum IgG antibody levels to native type II collagen were present in 42% of patients with RA, 30% with AS, and none of the patients with psoriatic arthritis. In rheumatoid arthritis there was a lack of correlation between IgG antibody levels to collagen and the erythrocyte sedimentation rate, IgG rheumatoid factor, and circulating immune complexes measured by the Clq-binding activity. In ankylosing spondylitis IgG antibody levels to native type II collagen were raised only in patients with peripheral joint involvement. The significance of IgG anticollagen antibodies is not certain, but parallels with rheumatoid factor are discussed.

Adult↗
PubMed1980

Native type II collagen-induced arthritis in the rat. I. Incidence and humoral response to collagen.

An acute inflammatory arthritis has been induced in 76% of rats injected intradermally with native bovine type II collagen emulsified in Freund's complete (CFA) or incomplete (ICFA) adjuvant. The arthritis became chronic in 14 out of 31 rats, and ear and tail lesions were noted in some rats. No arthritis was induced by native type I collagen, denatured type II collagen, rabbit IgG, or buffer alone injected intradermally with adjuvant. Using a solid-phase radioimmunoassay for serum antibodies we have shown that IgM and IgG levels to native bovine type II collagen were significantly higher in arthritic than nonarthritic rats. Antiglobulin antibody levels were not raised in arthritic rats. Equivalent antibody levels to native type II collgen were obtained whether this antigen was emulsified in ICFA or CFA. However, native type I collagen produced high antibody levels only when emulsified in CFA, indicating a difference in the immunogenicity of these collagens. These studies suggest that native type II collagen possesses arthritogenic properties in the rat and that humoral immunity may play a role in the induction of this arthritis.

Animals↗
PubMed1977

Steroid and FSH action on LH receptors and LH-sensitive testicular responsiveness during sexual maturation of the rat.

This study examines the effect of FSH, testosterone and estradiol on testicular LH receptors and in vitro testicular responsiveness to LH in immature rats under various conditions. FSH treatment of 15-day-old immature rats significantly increased the number of LH receptors but did not alter testicular responsiveness. FSH treatment of hypophysectomized immature rats increased the number of LH receptors and markedly increased testicular responsiveness. Treatment of hypophysectomized rats with testosterone proprionate for 4 days, followed by a 5-day treatment with FSH, enhanced the effect of FSH on the number of LH receptors but did not increase the effect of FSH on testicular responsiveness. In contrast, treatment with estradiol for 4 days before FSH treatment had no effect on the FSH-induced increase in LH receptors but completely inhibited the FSH-induced increase in testicular responsiveness. These observations suggest that during male sexual maturation (1) regulation of LH receptors is distinct from regulation of testicular responsiveness to LH, (2) estradiol may be a factor in the regulation of testicular responsiveness to LH, and (3) testosterone may enhance the FSH-induced increase of LH receptors.

Animals↗
PubMed1976

Exeriences with isoprenaline induced myocardial necrosis in the rat.

An attempt has been made to quantify myocardial lesions produced in the rat by isoprenaline for use as a model to assess possible incremental effects of environmental and dietary factors. This was initially made difficult by variation in the cardiotoxicity of different samples of isoprenaline. Investigation of these samples failed to reveal the basis for the differences. Active preparations have, however, produced profound changes both clinically and pathologically. The earliest light-microscopic changes both clinically and pathologically. The earliest light-microscopic change was loss of fuchsinophilia of fibres in sections stained by the picro-Mallory technique. By 24 hr obvious necrosis, fragmentation and lysis of the fibres had occurred. Treatment of frozen sections to demonstrate succinate dehydrogenase showed early changes in the character of formazan, suggesting the possibility of a transient alteration in the hydrogen transport system. By 48 hr, this is reversed except in those fibres undergoing necrosis where there is a complete loss of formazan. This contrast in staining between normal and necrotic fibres constitutes the basis for quantification which has been carried out by point counting. The results show some differences in the amount of myocardial necrosis between different batches of animals but relatively small differences within individual batches, suggesting that the introduction of additional variants into the system should be capable of producing clear cut results.

Animals↗