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Biomedical subjects

J Webb

Publications and source records attributed to J Webb.

At least 181 records · Page 10Linked to original sources
PubMed1986

Measurement of serum DNA binding in chronic active hepatitis and systemic lupus erythematosus using the Farr assay.

Antibodies to double-stranded DNA (dsDNA), generally regarded as highly specific for systemic lupus erythematosus (SLE), have also been reported in chronic active hepatitis (CAH). Using the Farr assay and E. coli DNA, fractionated by benzoylated-naphthoylated-DEAE cellulose chromatography into dsDNA and dsDNA containing single-stranded regions, we compared the serum DNA binding of CAH and SLE patients. Although CAH sera were found to have dsDNA binding significantly above the normal control group such binding was of low level and we could find no evidence of markedly elevated dsDNA binding in CAH. However 12 of the 20 CAH sera studied did bind preferentially to dsDNA containing single-stranded regions suggesting the presence of anti-single-stranded DNA antibodies. We conclude that the description of elevated anti-dsDNA antibodies, as measured by the Farr assay, in CAH is due to the interaction of anti-single-stranded DNA antibodies or other serum components with single-stranded DNA contaminating dsDNA preparations.

Adult↗
PubMed1986

The effects of copper nutrition and developmental state on the biosynthesis of diamine oxidase in clover leaves.

The biosynthesis of diamine oxidase (DAO; EC 1.4.3.6) in leaf blades of subterranean clover (Trifolium subterraneum L. cv Seaton Park) was followed by labeling whole plants with (14)CO(2). A pulse-chase experiment where DAO was immunoprecipitated with anti-DAO antibodies showed that only leaf primordia and the youngest emerged leaves were able to synthesize the enzyme. The amount of DAO in young leaves of clover grown with a range of Cu treatments was determined by its enzymic activity and by single radial immunodiffusion against anti-DAO antibodies; both parameters were highly correlated with the Cu concentration of the leaf. Further, anti-DAO antibodies reacted against apo-DAO prepared in vitro indicating that apo-DAO was absent from Cu-deficient leaves. These results suggest that the biosynthesis of DAO in young clover leaves is controlled by the Cu concentrations of the leaves. Poly(A) mRNA purified from leaf primordia and young emerging leaves of plants with either a high Cu or low Cu supply was translated in wheat germ and rabbit reticulocyte cell-free systems. No differences between the two Cu treatments could be seen in the sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles of the translation products after fluorography. However, anti-DAO antibodies did not detect any DAO synthesized in vitro from either treatment.

Journal Article↗
PubMed1986

Complement and immune complex diseases.

Research during the past decade has led to a much greater understanding of the activation and control, as well as a more complete delineation, of the complement system of proteins. There has been definition of the roles of individual components in modulation of immune complex formation, the deposition of which leads to tissue injury in the autoimmune connective tissue diseases. The ability of serum to render immune complexes more soluble is complement-mediated and appears to be an important protective mechanism against immune complex diseases. Inherited deficiencies and production of non-functional variants of complement components, decreased synthesis, hypercatabolism, and the presence of serum inhibitors may all contribute to the reduced immune complex solubilisation which has been found in the connective tissue diseases. More work is required to define further the role of complement and immune complexes in the basic pathogenesis of these diseases.

Antigen-Antibody Complex↗
PubMed1986

Cytophagic panniculitis.

A 60 year old woman developed generalised erythema nodosum-like lesions together with hectic fever, lymphadenopathy, and hepatitis. Biopsies revealed lobular panniculitis with a benign histiocytic infiltrate and prominent phagocytosis in subcutaneous sites, lymph nodes, and bone marrow. All immunological, serological, and culture studies were negative, apart from throat isolation of herpes simplex. The patient responded to high-dose corticosteroids. The case illustrates the differential diagnosis of lobular panniculitis, with histiocytic infiltrate and cytophagocytosis. These combined features are consistent with the recently described syndromes of cytophagic panniculitis and virus-associated hemophagocytic syndrome.

Erythrocytes↗
PubMed1986

Inhibition of complement-mediated solubilisation of antigen-antibody complexes by serum factor(s) in patients with various connective tissue diseases.

Control of immune complex formation is important to limit disease resulting from their deposition in tissues. Any inhibition of immune complex solubilisation is thus significant in the pathogenesis of immune complex diseases. More than half of our patients with various rheumatic connective tissue diseases were demonstrated to have serum inhibition of immune complex solubilisation (12/16 rheumatoid arthritis, 22/37 systemic lupus erythematosus, 16/29 primary Sjogren's syndrome, and eight of nine with mixed connective tissue disease). This serum inhibitory activity did not correlate well with serum levels of IgM rheumatoid factor or circulating immune complexes, and its nature remains to be elucidated.

Antibodies, Antinuclear↗
PubMed1986

Calcification is rare in adult-onset dermatopolymyositis.

Extensive subcutaneous and muscular calcification developed in a patient having adult-onset dermatopolymyositis (DM-PM) with an 'overlap' connective tissue disease. We wish to emphasize the rarity of calcification in adult onset DM-PM, which is contrary to the generally held impression.

Adult↗
PubMed1985

Iron chelation by pyridoxal isonicotinoyl hydrazone and analogues in hepatocytes in culture.

Pyridoxal isonicotinoyl hydrazone (PIH) and several analogues were synthesized and assessed in the rat hepatocyte culture for their potential in iron chelation therapy. Pyridoxal isonicotinoyl hydrazone and pyridoxal benzoyl hydrazone were as effective as desferrioxamine (DFO) in reducing both net uptake of rat transferrin-59Fe and incorporation into ferritin by hepatocytes. Dialysis studies showed that this was due to a cellular action and not to the extracellular chelation of transferrin-bound 59Fe. The analogues of PIH were more effective in mobilization studies than PIH and DFO, releasing more 59Fe from ferritin as well as from the stroma-mitochondrial membranes in hepatocytes prelabelled using transferrin-59Fe. Chelator action was dependent on incubation time, concentration, temperature and lipophilicity. Pyridoxal benzoyl hydrazone, the most effective iron chelator, was also the most lipophilic, suggesting that access to cellular iron compartments as well as iron-binding affinity is important in effective iron chelation.

Animals↗
PubMed1985

Paralysis and unilateral arthritis: is the association established?

A patient with long-standing upper limb lower motor neurone paresis more recently developed homolateral upper motor neurone hemiplegia. Subsequent primary generalised osteoarthritis spared only the paralysed upper limb. Detailed review of reported cases suggest that the "protective" effect of paralysis against subsequent development of arthritis is not as clearly established as generally believed.

Aged↗
PubMed1985

Development of three copper metalloenzymes in clover leaves.

Subterranean clover (Trifolium subterraneum L. cv Seaton Park) was grown in solution cultures containing adequate nitrogen both with and without Cu. After Cu deficiency had developed, Cu(2+) was added to some deficient plants and Cu content, protein content, and activities of three Cu metalloenzymes (diamine oxidase [EC1.4.3.6], ascorbate oxidase [EC1.10.3.3] and o-diphenol oxidase [EC1.10.3.1]) were assayed in young and recently matured leaf blades over 11 days during the development of the next three leaves.Copper deficiency had little effect on protein concentrations, but markedly depressed enzyme activities and Cu concentration in all leaf blades assayed. Within 4 d of adding Cu(2+) to Cu-deficient plants, Cu concentrations of all the leaf blades increased to adequate values. Enzyme activities only increased to control levels in leaves which had not yet emerged at the time that Cu(2+) was added.The results suggest that active holoenzymes of diamine oxidase, ascorbate oxidase, and o-diphenol oxidase can only be synthesized in leaf blades during very early stages of their development.

Journal Article↗
PubMed1985

Dramatic and rapid shrinkage of a massive invasive prolactinoma with bromocriptine: a case report.

Shrinkage of a massive, highly invasive, longstanding (probably 40 years) prolactin-secreting pituitary tumour is described in which tumour volume was reduced by 40% 8 d after beginning bromocriptine treatment. After 4 months of treatment the tumour was only 11% of the pretreatment volume and by 8 months it was further reduced in size being confined to the pituitary fossa, which was partially empty. Reduction in tumour volume was accompanied by a gradual reduction in serum prolactin concentrations to normal values at 4 months. Between 4 and 18 months serum prolactin has remained normal on 5 mg of bromocriptine daily. Visual function improved within 48 h of starting bromocriptine and was almost normal by 6 d. CSF rhinorrhoea developed as the tumour shrank and was successfully managed with the relatively minor procedure of a diversionary lumbo-peritoneal shunt. Bromocriptine should be considered as the initial treatment of choice for massive invasive prolactinomas because of the significant risk of morbidity from neurosurgical treatment.

Bromocriptine↗
PubMed1985

Autonomic regulation of postprandial plasma somatostatin, gastrin, and insulin.

To evaluate the neural regulation of postprandial somatostatin release we studied the effect of blockade of (a) alpha-adrenergic and beta-adrenergic and (b) cholinergic receptors on the plasma somatostatin, gastrin and insulin responses to a standard meal in two groups of five fasting healthy male volunteers. Thymoxamine (0.1 mg/kg iv over two minutes then 10 mg/hour for two hours) and propranolol (0.15 mg/kg iv over two minutes, then 0.75 mg/kg/hour for two hours) were started just before eating while atropine (0.04 mg/kg/im) was given at 15 minutes on completion of the meal. There was a prompt and sustained rise in plasma somatostatin after a control meal in all experiments. This rise was arrested by atropine but not altered by either thymoxamine or propranolol. The plasma gastrin response to a meal was moderately enhanced by thymoxamine and markedly enhanced by atropine. Postprandial insulin release was not affected by alpha- or beta-adrenergic blockade but was abolished by atropine. The effect of atropine on the postprandial plasma somatostatin rise might have been mediated through reduction in gastric acidity or delay in gastric emptying. Hence we gave five fasting male volunteers and intraduodenal infusion of fat emulsion (25 calories in 30 minutes) on two occasions both alone and after atropine. Plasma somatostatin rose during the fat infusion alone and this rise was abolished by atropine. These data suggest that (a) cholinergic but not adrenergic mechanisms are important modulators of plasma somatostatin release after orally ingested and intraduodenally infused nutrients (b) atropine abolishes plasma somatostatin release independently of its effects on gastric acidity and motility and (c) are consistent with the hypothesis that atropine potentiates postprandial gastrin release through reduction of somatostatin mediated inhibition.

Adult↗
PubMed1985

A follow-up study of cross-cultural validity of Developmental Test of Visual-motor Integration.

A follow-up study with a younger group of mildly handicapped Japanese students was conducted to determine if the correlations between the Developmental Test of Visual-motor Integration and reading and mathematics achievement would substantiate the previous findings. For 30 mildly handicapped 11- and 12-yr.-old Japanese students, visual-motor integration scores were significantly correlated with both mathematics and reading scores. These results, added to the 1984 Webb and Abe data, further support the test's cross-cultural validity.

Achievement↗
PubMed1985

Streptococcus group G septic polyarthritis.

A case of streptococcus group G polyarthritis has been identified from blood and synovial fluid cultures and was sensitive to penicillin G. The clinical tendency to polyarticular infection by this organism and its discordant response to the antibiotics indicated by in vitro studies are discussed.

Arthritis, Infectious↗