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Biomedical subjects

S Hatano

Publications and source records attributed to S Hatano.

At least 91 records · Page 5Linked to original sources
PubMed1986

Actin-fragmin interactions as revealed by chemical cross-linking.

A one to one complex of actin and fragmin (a capping protein from Physarum polycephalum plasmodia) was cross-linked with 1-ethyl-3-[3-(dimethylamino)propyl] carbodiimide. The cross-linking reaction generated two cross-linked products with slightly different molecular weights (88 000 and 90 000) as major species. They were cross-linked products of one actin and one fragmin. The cross-linking site of fragmin in the actin sequence was determined by peptide mappings [Sutoh, K. (1982) Biochemistry 21, 3654-3661] after partial chemical cleavages of cross-linked products with hydroxylamine. The results indicated that the N-terminal segment of actin spanning residues 1-12 participated in cross-linking with fragmin. The cross-linker used in this study covalently bridges lysine side chains and side chains of acidic residues when they are in direct contact. Therefore, it seems that acidic residues in the N-terminal segment of actin (Asp-1, Glu-2, Asp-3, Glu-4, and Asp-11), at least some of them, are in the binding site of fragmin. It has already been shown that the same acidic segment of actin is in the binding site of myosin or depactin (an actin-depolymerizing protein isolated from starfish oocytes). We suggest that the unusual amino acid sequence of the N-terminal segment of actin makes its N-terminal region a favorable anchoring site for various types of actin-binding proteins.

Actin Depolymerizing Factors↗
PubMed1986

Falls in the institutionalized elderly in Japan.

Falls can be considered a vital factor in impeding successful aging in the elderly. The purpose of the study is to know rates of falls per year among the elderly, to observe the situations when falls occurred, and to clarify the association of falls with physical deterioration. The survey was carried out in 1406 residents aged 65 and over of the Tokyo Metropolitan Home for the Elderly in 1982. The rate of subjects who fell more than once during a one-year period was 14.5%. Females had a higher rate than males. Sixty per cent of all the falls occurred indoors. As for the cause of the falls, extrinsic factors were accounted three times as much as intrinsic factors. Among injuries sustained by the falls, fracture was more frequent in females than in males. Length of time of standing on one leg was shorter for fallers than for non-fallers in both sexes. However, the differences were not significant when age was controlled. Fall is attributed not only to physical factors but also to environmental factors. Therefore, it should be encouraged to design an environment with devices.

Accidents↗
PubMed1986

Memory changes in the Benton Visual Retention Test between ages 70 and 75.

The influences of education and activity on memory of Japanese older adults were investigated. The Benton Visual Retention Test was given to 302 individuals (145 men and 157 women) aged 69 to 71 (average age 70) living in a suburb of Tokyo. Participants were retested 5 years later (average age 75). Memory as evaluated by Benton correct scores declined in both men and women during the 5 years. The influence of the first time Benton score, education, activity, and sex on the second-time Benton score was analyzed by multiple regression analysis. The second Benton score was strongly influenced by the initial score. Level of education and activity contributed to memory after 5 years. No difference in the magnitude of memory changes was found between men and women. The first time Benton score by education term showed a weak but negative contribution.

Activities of Daily Living↗
PubMed1985

Cushing's disease: pituitary microadenoma demonstrated by high resolution computed tomography with thin slices.

A girl 16 7/12 years of age with Cushing's disease secondary to pituitary microadenoma is described. The tumor was very clearly demonstrated by high-resolution contrast-enhanced computed tomography (CT) with thin slices and was removed by transsphenoidal microadenomectomy. In some patients with Cushing's disease levels of ACTH and cortisol are not always high. Therefore, high-resolution contrast-enhanced CT with thin slices should be performed when the diagnosis of Cushing's disease is suspected even when the definite diagnosis cannot be established by endocrinological examinations.

Adenoma↗
PubMed1985

Studies of serum lipoproteins of adolescent Japanese and U.S. (Bogalusa) children using a common laboratory.

A cross-cultural comparison of serum lipoprotein profiles was made between adolescent children ages 12, 15, 16, and 17 years from the United States (Bogalusa) and Japan using a common laboratory. Characteristically, adolescent white children have relatively low total and alpha-lipoprotein cholesterol levels and high pre-beta-lipoprotein cholesterol, while black children have high total and alpha-lipoprotein cholesterol levels and low triglycerides; Japanese children, in contrast, have high total and beta-lipoprotein cholesterol and disproportionately high triglyceride levels in relation to low levels of pre-beta-lipoprotein cholesterol. The sex-related differences were similar among Japanese and white children, with boys showing lower alpha-lipoprotein cholesterol and higher triglyceride levels than girls. In terms of changes in beta-lipoprotein cholesterol/alpha-lipoprotein cholesterol ratios with age, the values showed an increase among white boys, no change among black children, and a decrease among white girls as well as among Japanese children of both sexes. There was no inverse relationship between alpha-lipoprotein cholesterol and triglycerides or pre-beta-lipoprotein cholesterol in Japanese children. These observations suggest intrinsic metabolic differences among these race-sex groups. Such information should help elucidate environmental factors that influence cardiovascular risk among varied cultures.

Adolescent↗
PubMed1985

Trace elements (copper, zinc, manganese, and selenium) in plasma and erythrocytes in relation to dietary intake during infancy.

All determinations of copper, zinc, manganese, and selenium were performed with a flameless atomic absorption spectrophotometer. Seventy-three full-term infants aged 1 to 52 weeks were divided into three age groups. Each age group contained two subgroups, breast-fed and formula-fed. No statistically significant differences between formula-fed and breast-fed subgroups were found in regard to the levels of copper and zinc in plasma and erythrocytes. At 1 to 5 weeks of age, the manganese concentration of erythrocytes was higher in formula-fed than in breast-fed infants (p less than 0.001). This might be due to the high dietary intake of this element in the formula-fed subgroup. On the other hand, plasma selenium concentrations were significantly higher in breast-fed than in formula-fed infants of all ages (p less than 0.01 at 1 to 5 weeks and p less than 0.05 at 6 to 52 weeks). This suggests that selenium compounds are biologically more available for infant nutrition in breast milk than in formula.

Copper↗
PubMed1985

Zinc, copper, manganese, and selenium metabolism in patients with human growth hormone deficiency or acromegaly.

This study was designed to evaluate trace metal metabolism in patients with known abnormalities of human growth hormone (hGH). The mean concentration of zinc in plasma and urine decreased in patients with hGH deficiency after hGH injection, whereas, after adenomectomy, in patients with acromegaly, zinc increased in plasma, remained the same in erythrocytes, and decreased in urine. There was a negative correlation between plasma zinc and serum hGH levels and a positive correlation between urinary zinc excretion and serum hGH levels in acromegaly. In hGH deficiency, the copper content remained unchanged in plasma and erythrocytes and rose in urine after treatment; however, in acromegaly, the copper content increased in plasma and remained unchanged in erythrocytes and urine after surgery. The mean concentration of erythrocyte manganese did not change significantly after treatment in patients with hGH deficiency or acromegaly, but the pre-hGH treatment level of erythrocyte manganese in hGH deficiency was lower than in the controls. Plasma selenium concentrations were decreased in hGH deficiency and increased in acromegaly patients after therapy. These results suggest that hGH affects the metabolism of zinc, copper, manganese, and selenium.

Acromegaly↗
PubMed1984

Ca2+-dependent contraction of human lung fibroblasts treated with Triton X-100: a role of Ca2+-calmodulin-dependent phosphorylation of myosin 20,000-dalton light chain.

Human lung fibroblast MRC-5 cells treated with Triton X-100 (MRC-5 cell models) were able to contract in the presence of MgATP and Ca2+ of more than 1 microM. Immunofluorescence microscopy with antibodies to actin and myosin 20,000-dalton (20 Kd) light chain revealed that stress fibers were prominent in MRC-5 cell models. Use of a fluorescent actin probe, 7-nitrobenz-2-oxa-1,3-diazole-phallacidin permitted visualization of contraction of the stress fibers in the presence of MgATP and Ca2+. Of the proteins in MRC-5 cell models, only a myosin 20 Kd light chain was phosphorylated in a Ca2+-dependent manner. This Ca2+-dependent phosphorylation of the 20 Kd light chain closely corresponded with the contraction of MRC-5 cell models: 1) Both phosphorylation of the 20 Kd light chain and contraction of MRC-5 cell models were inhibited by calmodulin antagonists such as N-(6-aminohexyl)5-chloro-1-napthalene sulfonamide. 2) The threshold Ca2+ concentration for phosphorylation of the 20 Kd light chain was similar to that for contraction of MRC-5 cell models. Both were lowered by exogenous calmodulin in a concentration-dependent manner. 3) The 20 Kd light chain was thiophosphorylated by incubation of MRC-5 cell models with an ATP analogue, adenosine 5'-0-(3-thiotriphosphate) only in the presence of Ca2+. After this treatment, MRC-5 cell models lost the Ca2+-dependence for contraction. These results indicate that Ca2+-calmodulin-dependent phosphorylation of myosin 20 Kd light chain is required for contraction of MRC-5 cell models.

Adenosine Triphosphate↗
PubMed1984

Configurational changes in rat liver nuclear chromatin caused by azo dyes.

The effects of azo dyes on the chromatin configuration of isolated rat-liver nuclei were examined by electron microscopy for elucidation of the mechanism of dye-stimulated in vitro RNA synthesis. Sunset Yellow FCF had no effect on the incorporation of [3H]UTP into RNA but amaranth and Ponceau 3R stimulated incorporation approximately two- and 3.5-fold, respectively. Sunset Yellow FCF did not produce any major alteration in liver nuclei. Isolated liver nuclei treated with amaranth or Ponceau 3R showed dissociation of heterochromatin and the nucleoli lost their fine-granular structure acquiring a coarse-granular configuration. The dense structure of heterochromatin in liver nuclei treated with Ponceau 3R was completely dissociated and appeared as a lace-like configuration. These results suggest that both Ponceau 3R and amaranth stimulate in vitro RNA synthesis by causing the dissociation of heterochromatin in isolated rat-liver nuclei.

Amaranth Dye↗
PubMed1984

Mechanism of regulation of actin polymerization by Physarum profilin.

Physarum profilin reduces the rates of nucleation and elongation of F-actin and also reduces the extent of polymerization of actin at the steady state in a concentration-dependent fashion. The apparent critical concentration for polymerization of actin is increased by the addition of profilin. These results can be explained by the idea that Physarum profilin forms a 1:1 complex with G-actin and decreases the concentration of actin available for polymerization. The dissociation constant for binding of profilin to G-actin is estimated from the kinetics of polymerization of G-actin and elongation of F-actin nuclei and from the increase of apparent critical concentration in the presence of profilin. The dissociation constants for binding of Physarum profilin to Physarum and muscle actins under physiological ionic conditions are in the ranges of 1.4-3.7 microM and 11.3-28.5 microM, respectively. When profilin is added to an F-actin solution, profilin binds to G-actin which co-exists with F-actin, and then G-actin is dissociated from F-actin to compensate for the decrease of the concentration of free G-actin and to keep it constant at the critical concentration. At the steady state, free G-actin of the critical concentration is in equilibrium not only with F-actin but also with profilin-G-actin complex. The stoichiometry of 1:1 for the formation of complex between profilin and G-actin is directly shown by means of chemical cross-linking.

Actins↗
PubMed1984

Zinc, copper, manganese, and selenium metabolism in thyroid disease.

This study was designed to evaluate trace metal metabolism in adults with thyroid diseases. Erythrocyte zinc values were significantly lower than normal in hyperthyroidism and higher in hypothyroidism. A significantly higher than normal urinary excretion of zinc was observed in hyperthyroidism. The mean concentrations of plasma and erythrocyte copper were significantly above normal in hyperthyroidism. Plasma selenium levels were significantly lower than normal in hyperthyroidism. No statistically significant difference was found in plasma zinc, erythrocyte manganese, or urine copper values between patients with thyroid diseases and healthy controls. The erythrocyte manganese content correlated well with thyroxine and triiodothyronine levels. Plasma prealbumin and retinol-binding protein correlated well with the erythrocyte zinc content but not with plasma zinc levels. There was no correlation between erythrocyte superoxide dismutase activity and erythrocyte copper or zinc concentrations. The results of this study suggest that the metabolism of zinc, copper, manganese, and selenium is abnormal in thyroid diseases.

Adolescent↗
PubMed1984

Plasma selenium concentration in healthy Japanese children and adults determined by flameless atomic absorption spectrophotometry.

This study showed a rapid and direct method for determining selenium concentration in plasma by flameless atomic absorption spectrophotometry, and differences in plasma selenium concentration in healthy children and adults. A direct method is possible, since selenium is heat stable in the presence of nickel. With this method, the recovery of selenium added to plasma was 100.3 +/- 5.7%, and the relative standard deviation in repeated determinations of pooled plasma selenium was 3.0% and 6.8%. The plasma selenium concentration in adults was 99.4 +/- 12.5 ng/ml, lower than reported concentrations from the United States and Canada, and higher than those from New Zealand. These variations may reflect dietary habits, bioavailability of selenium compounds in diet, racial difference, or different analytical methods. The mean concentration of plasma selenium at 1 to 6 months of age (51.0 +/- 13.1 ng/ml) was significantly lower than in adults (p less than 0.001); it increased gradually and steadily to the adult level with age. This age-related difference of plasma selenium level is similar to that reported previously.

Adolescent↗
PubMed1984

Effect of zinc ion on human chorionic gonadotropin-stimulated in vitro production of cyclic AMP and testosterone by rat testis.

This study explores the effects of several divalent metal ions on the in vitro production of cyclic AMP, cyclic GMP, and testosterone by rat testicular tissue and on the amount of binding of [125I]human chorionic gonadotropin (hCG) in the testis. Zn2+ at concentrations of 10(-6) to 10(-4) M enhanced the hCG-stimulated production of cyclic AMP and testosterone, but only in the presence of Ca2+ X [125I]hCG binding to rat testicular tissue was not affected by Zn2+ X Cu2+, Ni2+, Co2+, and Mn2+ did not increase cyclic AMP or testosterone production in concentrations of 10(-7) to 10(-3) M and even inhibited them at a high concentration (10(-2) M). Cyclic GMP production was not affected by these divalent ions. These results suggest that Zn2+ may play an important role in rat testicular steroidogenesis.

Animals↗