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Biomedical subjects

T Usui

Publications and source records attributed to T Usui.

At least 451 records · Page 25Linked to original sources
PubMed1985

Inhibition by adenine of in vitro immunological functions of normal and adenine phosphoribosyltransferase-deficient human lymphocytes.

Exogenous adenine strongly inhibited mitogen-stimulated transformation, cytoplasmic immunoglobulin production, and natural killer activity of human mononuclear leukocytes at the high concentration of 1.0 mM. These inhibitions by adenine were not due to cytotoxicity, because the viability of cultured cells was not affected by adenine up to 1.0 mM. As the magnitude of inhibition by adenine of these in vitro immunological functions was similar in normal and adenine phosphoribosyltransferase-deficient cells, its inhibition was not mediated by corresponding nucleotides. Adenine at the concentration of 0.1 mM caused 50% inhibition of cytoplasmic immunoglobulin production without alternating cell proliferation or viability. This suggests that an appropriate concentration of adenine may inhibit the differentiation of B cells to plasma cells rather than affecting cell proliferation. Understanding the mechanisms of adenine inhibition may lead to new approaches for the regulation of immune responses.

Adenine↗
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

Influence of diet on the development of gastrin- and somatostatin-like immunoreactivity in the stomach of rats.

The effects of changes in diet on antral gastrin-like immunoreactivities and antral and corporal somatostatin-like immunoreactivities were studied in three groups of young male rats. Group 1 rats were weaned physiologically, group 2 rats received only breast milk, and group 3 rats were fed milk until 20 days of age and then were switched abruptly to laboratory chow. In group 1, antral gastrin-like immunoreactivity and somatostatin-like immunoreactivity increased gradually from 13 days of age to adults. In group 2, antral gastrin-like immunoreactivity did not increase, and antral and corporal somatostatin-like immunoreactivity increased until 20 and 25 days of age, respectively. In group 3, there were three- to fivefold increases of antral gastrin-like immunoreactivity and somatostatin-like immunoreactivity after changing to laboratory chow. Dietary changes had no effect on the concentration of corporal somatostatin-like immunoreactivity. These results suggest that the developmental patterns of gastric gastrin-like immunoreactivity and somatostatin-like immunoreactivity are closely related to diet; laboratory chow may play an important role in the development of these gut hormones.

Animals↗
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↗
PubMed1985

A case of prostatic carcinoma with skin metastases.

The 30th case of metastatic skin carcinoma of prostatic origin was presented. The cytosolic R1881 receptor was detected moderately in the metastatic nodule of the skin, however, the measurement of this receptor had a limited value for the purpose of treating the patient with antiandrogenic agents.

Adenocarcinoma↗
PubMed1985

Distribution of neurotensin-like immunoreactivity in the hypothalamus, pituitary gland, and gastro-intestinal tract of rats.

The distribution of neurotensin-like immunoreactivity (NTLI) in the pituitary gland, hypothalamus, and throughout the gastro-intestinal tract of adult rats was determined by radioimmunoassay (RIA). NTLI concentrations were higher in the hypothalamus than in the pituitary gland or gastro-intestinal tract. The anterior and posterior pituitary gland had almost the same concentration of NTLI. In the gastro-intestinal tract, the mucosal layer of the small intestine had abundant NTLI. The mucosal layer had higher NTLI levels than the muscular layer throughout the alimentary tract.

Animals↗
PubMed1985

LPF-induced T cell colony formation: effect of PMA and interleukin-2, and surface marker analysis.

We demonstrated that a primary exposure to the lymphocytosis promoting factor (LPF) of Bordetella pertussis-induced T cell colony formation. Colony formation was observed when mononuclear cells (MNC) were cultured at concentrations of more than 1 X 10(6)/ml, and reached a peak on day 8. However, the number of colonies generated with LPF was about one-third induced with phytohaemagglutinin (PHA). Removal of monocytes from MNC or T cells resulted in the failure of colony formation, but colony growth could be restored by the addition of monocytes or B enriched cells, indicating that they were required for the optimal colony growth induced by LPF. In the absence of accessory cells, optimal colony growth from monocyte depleted T cells could be obtained when an appropriate concentration of phorbol myristate acetate (PMA) or interleukin-2 (IL-2) was added in the cultures with LPF. PMA did not enhance LPF-induced colony formation in the cultures containing a sufficient amount of exogeneous IL-2. These findings suggest that IL-2 is essential to LPF-induced colony formation. Surface marker analysis showed that most of LPF-induced colony cells were T cells. The percentages of T4+ and T gamma cells of LPF-induced colony cells were more, and T8+ cells less, than those of PHA-induced colony cells. Ia1, T9 and Tac antigens were detected on many colony cells induced by LPF or PHA. These results indicate that the phenotype of LPF-induced colony cells differs from those of PHA, but the sequential antigen expression on lymphocytes triggered by IL-2 might be similar in both LPF- and PHA-induced colony formation.

Antigens, Surface↗