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Biomedical subjects

J R Klinenberg

Publications and source records attributed to J R Klinenberg.

At least 91 records · Page 5Linked to original sources
PubMed1973

Uric acid. Characterization of its interaction with human serum albumin.

Binding of sodium urate to human serum albumin (HSA) was measured by continuous ultrafiltration at pH 7.4 and ionic strength 0.16 over the concentration range 1-13 mg/100 ml. The percent sodium urate bound to 5 g/100 ml HSA was constant over this concentration range: 30.3 (SE+/-0.6)% being bound at 4 degrees C, 22.6+/-0.3% at 22.5 degrees C, and 19.6+/-0.3% at 37 degrees C. Derived association constants, assuming one binding site were 6.0 x 10(2) M(-1) (4 degrees C), 4.47 x 10(2) M(-1) (22.5 degrees C), and 3.88 x 10(2) M(-1) (37 degrees C).

Binding Sites↗
PubMed1972

The effect of azathioprine on gammaglobulin synthesis in man.

The effect of azathioprine therapy on gammaglobulin synthesis was evaluated in nine patients with rheumatic disorders. The rates of synthesis of IgG and IgM were calculated before and after 4 months of azathioprine treatment using turnover studies of radioiodinated gammaglobulins. The synthesis of IgG decreased 33.4% of the initial IgG synthetic rate. Seven of nine patients showed reductions of IgG synthesis ranging from 16.8 to 74.1%. IgM production decreased from 24.5 to 74.2% in eight of nine patients with a mean reduction of 40.9%. Studies before and after a control period of 4 months of placebo in six patients revealed a mean increase in IgG and IgM synthesis. Serum immunoglobulin concentrations after 4 months of azathioprine treatment were not consistently reduced and did not parallel changes in immunoglobulin synthesis. Reduced gammaglobulin synthesis may play a role in the therapeutic action of this and other "immunosuppressive" drugs.

Antibodies, Antinuclear↗
PubMed1970

Altered immunoglobulin metabolism in systemic lupus erythematosus and heumatoid arthritis.

IgG and IgM metabolism was evaluated in 10 patients with systemic lupus erythematosus (SLE), 10 patients with rheumatoid arthritis (RA), and in seven normal volunteers. The biological half-lives of purified IgG and IgM, labeled with (131)I and (125)I, respectively, were determined by serial measurements of radioactivity in the blood and urine with a gamma well counter, and by serial counts of total body radioactivity in a total body counting chamber. The mean survival half-life for IgG in patients with SLE was 8.2 days as compared to an average of 18 days in normal controls. An average of 10.1% of total body IgG was catabolized daily compared to a mean of 3.9% in normal controls. Turnover of IgM in patients with SLE was, with very few exceptions, normal. In contrast, patients with rheumatoid arthritis revealed a milder abnormality of IgG metabolism, but markedly abnormal IgM catabolism with a mean half-life averaging 5.9 days as compared to 9.3 days in control subjects. An average of 14.2% of total body IgM was catabolized daily in patients with RA as compared to 8.1% in normal controls. Our data suggest that there are basic differences between patients with RA and SLE in the synthesis and catabolism of IgG and IgM not readily apparent from serum IgG and IgM concentration. Abnormal IgG and IgM metabolism may be related to underlying immunological mechanisms in these diseases. Immunoglobulin turnover studies appear to be an additional means for the characterization of rheumatic diseases.

Adrenal Cortex Hormones↗
PubMed1969

Effect of drugs on urate binding to plasma proteins.

The effect of various drugs on urate binding to plasma proteins was investigated in normal subjects. Whereas allopurinol, aspirin, phenylbutazone, probenecid, and sulphinpyrazone all significantly reduced plasma urate concentrations, only aspirin, phenylbutazone, and probenecid significantly impaired urate binding. Colchicine and indomethacin in the doses administered had no significant effect on plasma urate concentrations or binding. In the case of aspirin, urate binding was reduced to 25% of normal, and this effect was quickly abolished after cessation of therapy. Phenylbutazone reduced urate binding to 56% and probenecid to 46% of normal; this impairment was still detected four days after cessation of therapy. Drugs may impair urate binding by competition for plasma protein binding sites, with displacement of bound urate. Impairment of urate binding in vivo by administration of certain drugs may be relevant to the precipitation of acute gouty arthritis, to the formation of gouty tophi, and to the augmentation of uricosuria. Furthermore, the role of drugs must be seriously considered during all studies on urate binding in patients with gout.

Adult↗