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L S Pletscher

Publications and source records attributed to L S Pletscher.

7 recordsLinked to original sources
PubMed1985

Mitogenic factors in prostatic tissue and expressed prostatic secretion.

Expressed prostatic secretions and extracts of benign prostatic hyperplasia tissue contain a polypeptide growth factor(s) that stimulates the uptake of tritium-labeled thymidine by cultured 3T3 fibroblasts. Mitogenic activity was present in expressed prostatic secretions and extracts of benign prostatic hyperplasia tissue. The apparent molecular weights of the mitogenic fractions were estimated to be 300,000, 150,000 and 60,000 daltons for prostatic tissue extracts, and 30,000 daltons for expressed prostatic secretions. Bioassays yielded a mean of 27 units of mitogenic activity per mg. protein in expressed prostatic secretions obtained from men with normal and enlarged prostate glands. There was no difference in bioassayable mitogenic activity in the expressed prostatic secretions from normal and benign prostatic hyperplasia samples but gel filtration studies revealed a high molecular weight component present only in samples from men with prostatic enlargement. A dialyzable low molecular weight inhibitor of fibroblast growth was found in the prostatic tissues and expressed prostatic secretions. We report the characterization studies and discuss the possible roles of growth factors in the pathogenesis of benign prostatic hyperplasia.

Cells, Cultured↗
PubMed1982

Suppression of the normal autologous mixed leukocyte reaction by sera from patients with systemic lupus erythematosus.

Sera from 15 patients with active systemic lupus erythematosus and 7 patients with inactive lupus were added to normal autologous mixed leukocyte reaction (MLR) cultures. Twelve of the 22 sera reduced autologous T cell proliferative responsiveness to B plus null (B + N) cells or macrophages by 50% or more. This inhibition correlated with defective autologous MLR in fresh mononuclear cells from those patients. When normal responding and stimulating cell populations were preincubated with suppressive lupus sera, then added to autologous MLR cultures that contained normal serum, proliferative responses were also reduced; inhibitors are directed against participating mononuclear cell subpopulations. The suppressive serum factors were directed variously against monocyte/macrophage (M phi), B + N, or T cell populations; M phi/T interactions were suppressed most frequently. The inhibitors were not removed by high-speed centrifugation or by depletion of antibodies to DNA, and they did not correlate with the presence of lymphocytotoxic antibodies. The presence of serum inhibitors of normal M phi/T and B + N/T autologous MLR may be an immunologic abnormality important in the initiation, perpetuation, or exacerbation of systemic lupus erythematosus.

Adult↗
PubMed1980

Immunosuppressive effects of low doses of glucocorticoids: effects on autologous and allogeneic mixed leukocyte reactions.

The effects of single oral doses of 10, 15, or 30 mg of prednisone on circulating mononuclear cells, autologous MLR, mitogen responses, and allogeneic MLR were studied in healthy volunteers. Doses as low as 10 mg were immunosuppressive, causing diminution of circulating T cells and monocytes, and significant reduction in autologous but not allogeneic MLR responses. These effects were maximal 6 hr after drug administration and gone by 24 hr. Autologous MLR responses were particularly sensitive to the effects of prednisone being significantly and consistently suppressed 2 hr after drug administration, before significant cell redistribution had occurred. Macrophage-enriched stimulating cells were more easily suppressed than responding T cells. Since the autologous MLR may be important in in vivo regulation of immune responses, its reduction by low-dose glucocorticoids may be of clinical relevance. This suppressive effect must be considered in studies of the autologous MLR in patients receiving glucocorticoid therapy.

Adult↗
PubMedDate not supplied

Immunosuppressive effects of deflazacort - a new glucocorticoid with bone-sparing and carbohydrate-sparing properties: comparison with prednisone.

Deflazacort is a synthetic glucocorticoid with fewer adverse effects on bone and carbohydrate metabolism than prednisone or beta-methasone. Its antiinflammatory effects have compared favorably to prednisone in European studies of rheumatoid arthritis. We compared the immune effects of prednisone and deflazacort in normal volunteers. Circulating lymphocytes were reduced similarly by equivalent doses of both drugs; monocyte numbers were reduced more by deflazacort. Each drug suppressed autologous mixed lymphocyte reaction in vitro and in vivo; this effect persisted longer with deflazacort. Deflazacort may be a superior therapeutic agent because of its lower toxicity and longer duration of one immunosuppressive effect; it might be effective in alternate day regimens.

Adult↗