Michizo Kishihara

Werner's syndrome: In vivo and in vitro characteristics as a model of aging☆

Abstract Three patients who suffered from Werners syndrome were studied to help to elucidate differences from and/or analogies to both clinical symptoms and biochemical changes in normal aging. Our patients commonly manifested graying of hair, atrophy and hyperkeratosis of the skin, cataracts and hypogonadism. Such alterations would appear to be analogous to normal aging phenomena. However, the types of cataracts, degree of skin changes and growth retardation in Werners syndrome differed from the normal aging phenomena. Studies of endocrine functions in our patients did not show definite evidence of generalized hypopituitarism and impaired function of hormone secretion. Resistance to hormones human cholionic gonadotropin (hCG), luteinizing hormone-releasing hormone (LH-RH) and insulin was observed, suggesting a possible alteration of a diversity of proteins which may affect hormone receptors. Immunologic aspects were also studied, since the genetically programmed failure of thymic function could play a major role in the pathogenesis of aging and age-related diseases. Our results in three patients did not indicate any definite immunologic abnormalities. Culture studies showed that skin fibroblasts in Werners syndrome exhibited more decreased potentials of in vitro clonal growth and elongation of newly synthesizing DMA as phenotypic expressions than did normal skin cells. Yet, in Werners syndrome, cells repaired DNA damage normally. The relationship of these findings to the basic genetic defect of Werners syndrome remains unknown.

Mitogenic response of human and murine T lymphocytes to staphylococcal protein A: Not mediated by binding to cell surface immunoglobulins

Abstract Staphylococcal protein A (SpA) stimulates human lymphocytes more efficiently than murine lymphocytes. The subsets of lymphocytes responding to SpA were heterogeneous. In the subsets, cortisone resistant, low Thy 1,2, minor populations of murine thymocytes and mature peripheral T lymphocytes were predominantly stimulated by SpA. Though SpA stimulated cortisone-resistant thymocytes, further treatment of these cells with anti-mouse immunoglobulin sera and guinea pig complement failed to influence the mitogenic response to SpA. It seems likely that SpA contains a substance stimulating T lymphocytes, through binding to sites other than the surface immunoglobulins.

Purification of calmodulin from human brain

Abstract Calmodulin was purified from human brain by ammonium sulfate precipitation, gel filtration, and anion exchange chromatography. The purified calmodulin was homogenous when evaluated by polyacrylamide gel electrophoresis. The biological and physicochemical properties of human brain calmodulin such as the ability to activate calmodulin-deficient bovine phosphodiesterase, molecular weight, and amino acid composition were almost the same as bovine brain calmodulin.

Effect of various drugs on the binding of thyrotrophin to thyroid plasma membranes.

Effects of enzyme inhibitors and membrane-active drugs on the binding of 125I-labelled thyroid-stimulating hormone (TSH) to human thyroid membranes and membrane adenylate cyclase (AC) activity were studied. FOY, a synthetic polyvalent proteolytic enzyme inhibitor, Trasylol, alpha- and beta-adrenergic blocking agents, tranquilizers, anti-histamines and polyene antibiotics enchanced TSH binding in a dose-dependent manner, whereas selective enzyme inhibitors and adrenergic stimulating agents had no effect. Both propranolol and FOY inhibited basal and TSH stimulated AC activity of thyroid membranes. FOY, as well as propranolol was found to have protective effects on hypotonic erythrocyte lysis. These results suggest that propranolol and FOY increased TSH binding by the same mechanism, probably the so-called membrane-stabilizing effects. Although the detailed mechanisms underlying the increased TSH binding by these drugs remain unknown, they may change the membrane structure, thereby enhancing the TSH receptor affinity.