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Biomedical subjects

K Tsuda

Publications and source records attributed to K Tsuda.

At least 343 records · Page 19Linked to original sources
PubMed1985

Ascites with peritoneal myeloid metaplasia in a patient with advanced non-Hodgkin's lymphoma.

Peritoneal myeloid metaplasia associated with ascites containing numerous hemopoietic cells in a patient with non-Hodgkin's lymphoma is described. It is suggested that massive infiltration of lymphoma cells into the bone marrow caused marrow failure and compensatory mechanisms supervened leading to myeloid metaplastic implants in the peritoneum associated with ascites as well as in the liver, spleen and lymph nodes. There was also a significant leuko-erythroblastic reaction in the peripheral blood.

Ascites↗
PubMed1985

Malignant lymphoma in the Miyazaki district: analysis of 237 biopsy cases.

Pretreatment biopsy specimens of 237 consecutive patients with malignant lymphoma, who presented to us from 1979 to 1982, were reviewed and reclassified. According to the new classification proposed by the Lymphoma Study Group of Japan (LSG), there were 226 patients with non-Hodgkin's lymphoma (NHL) which was further classified as diffuse lymphoma (216 cases), follicular lymphoma (4 cases), mycosis fungoides (4 cases), and others (2 cases). The 216 cases of diffuse NHL were subdivided into small cell (2 cases), medium-sized cell (71 cases), mixed (7 cases), large cell (92 cases), pleomorphic (40 cases), lymphoblastic (3 cases), and Burkitt's type (1 case) lymphoma. Cell surface marker studies using conventional methods were performed on 65 NHL patients, of whom 45 showed T-cell marker and 11 B-cell marker, and 8 had neither marker. The average survival periods were 13.1 mo for 107 patients with NHL, 27.9 mo for those with mycosis fungoides and 70.0 mo for 10 patients with Hodgkin's disease. Patients with adult T-cell leukemia survived for an average of only 5.5 mo. Histologically diffuse pleomorphic type had the worst prognosis. T-cell lymphoma appeared to have a poorer prognosis than B-cell lymphoma.

Adolescent↗
PubMed1985

Synthesis of cyclic silyl nucleosides having bulky groups on the silicon atom.

Synthesis of cyclic silyl nucleosides having bulky tert-butyl groups on the silicon atom has been investigated. Cyclic silyl deoxyribonucleosides having one tert-butyl group on the silicon atom was obtained without difficulty in the standard silylation reaction using dichlorosilane and imidazole. However, under similar conditions the reaction with di-tert-butyldichloro-silane proceeded only slowly by virtue of steric hindrance. The reaction has been largely improved by the use of 1-hydroxy-benzotriazole as a catalyst for silyl transfer and silver salts of acids to generate silylating reagents of high reactivity.

Indicators and Reagents↗
PubMed1984

Somatostatin, glucagon, and insulin secretion from isolated perfused pancreas of new genetically obese hyperglycemic rats.

Insulin, somatostatin, and glucagon release from the perfused pancreas was studied in the newly developed genetically obese hyperglycemic hyperinsulinemic (Wistar fatty) rat. Insulin and somatostatin levels rose significantly compared to those in lean littermate controls during arginine infusion. The glucagon increase, however, was significantly less when total amounts during arginine infusion were calculated. These results show that hypersecretion of insulin and somatostatin in vitro may suppress glucagon release in Wistar fatty rats.

Animals↗
PubMed1984

Different effects of prostaglandin E1, E2 and D2 on pancreatic somatostatin release.

The effects of PGE1, PGE2 and PGD2 on somatostatin, insulin and glucagon secretions were investigated at various glucose concentrations using the isolated perfused rat pancreas. At glucose concentrations varying from 0 to 16.7 mM, PGE1 and PGE2 enhanced somatostatin release in a glucose dose-dependent manner. PGE1 did not significantly stimulate insulin secretion at glucose concentrations of 4.4 mM or less, but did at glucose concentrations of 8.8 mM or more, PGE2 augmented insulin release at 4.4 and 16.7 mM glucose, but not in the absence of glucose. Glucagon release was induced by PGE1 and PGE2 in a biphasic pattern with the maximal response in the absence of glucose. Like PGE1 and PGE2, PGD2 stimulated insulin and glucagon release in a glucose-related fashion. PGD2, however, was not capable of stimulating somatostatin release at various glucose concentrations even in the presence of 16.7 mM glucose. In conclusion, PGE1, PGE2, and PGD2 increase insulin and glucagon secretion in a glucose-dependent manner. PGE1 and PGE2 also stimulate somatostatin release, but PGD2 has no effect on somatostatin secretion at the doses studied.

Alprostadil↗
PubMed1984

Changes in insulin, somatostatin, and glucagon secretion during the development of obesity in ventromedial hypothalamic-lesioned rats.

Changes in insulin, somatostatin, and glucagon secretion during the development of obesity in rats after ventromedial hypothalamic (VMH) lesions were evaluated by measuring fasting hormone levels and their secretion from the isolated perfused pancreas. Fasting peripheral insulin levels were not altered 1 week after the VMH lesions but became progressively elevated at 3-4, 8-9, and 11-12 weeks compared to the values in sham-operated and age-matched control rats. In the portal vein, insulin levels also progressively increased in VMH-lesioned rats, but the portal-peripheral gradient of insulin in the later phase of VMH obesity was significantly lower than in the early phase after VMH lesions. On the contrary, the arginine-induced insulin release from the perfused pancreas was highest at 1 week and gradually decreased thereafter, although it continued to remain higher than that of controls. The perfusate somatostatin response to arginine also was exaggerated in the VMH-lesioned rats. However, both the peripheral glucagon level and the glucagon secretion from the perfused pancreas of the VMH-lesioned rats were not significantly different from the controls. These results show that VMH lesions result in an increased insulin and somatostatin secretion. Using the cyclically perfused liver in situ, we have found that the hepatic extraction rate of insulin is indeed reduced in rats 8-9 weeks after VMH lesioning, and so have at least partly accounted for the decreased portal-peripheral gradient of insulin in the later VMH postoperative phase.

Animals↗
PubMed1984

Neurotransmitter release and vascular reactivity in spontaneously hypertensive rats.

This study was designed to investigate neurotransmitter release during the sympathetic nerve stimulation of perfused mesenteric arterial beds of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) at young and adult ages. The role of Ca in neurotransmitter release and vascular responsiveness was also examined by using a Ca-antagonist (verapamil). Pressor responses to electrical nerve stimulation and exogenous noradrenaline were greater in SHR than in WKY. Noradrenaline overflow by electrical nerve stimulation from mesenteric arterial beds was also significantly greater in young SHR than age-matched WKY. However, in adult SHR, the noradrenaline overflow was reduced compared with WKY. After verapamil infusion (5.0 X 10(-7)M approximately 2.5 X 10(-6)M), suppression of the pressor responses and noradrenaline overflow evoked by electrical nerve stimulation was greater in SHR than in WKY at both ages. The pressor responses to exogenous noradrenaline were also inhibited by verapamil more in young SHR than in young WKY. In adult SHR, the inhibition was similar to age-matched WKY. These results suggest that noradrenaline release from sympathetic nerve endings in SHR increase at a young age and decreases in adults, and depends at least partly on Ca-influx at both ages as dose vasoconstrictor reactivity. Therefore, Ca-dependency in SHR at both pre- and post-synaptic sites of neurotransmission may contribute to the pathogenesis of hypertension.

Animals↗
PubMed1984

Increased osmotic fragility of erythrocytes in essential hypertension.

The correlation between hypertension and the osmotic fragility of erythrocytes was examined. High osmotic fragility of erythrocytes was observed in patients with essential hypertension and normotensive subjects with family history of hypertension, compared with normotensive controls without family history of hypertension. In patients with secondary hypertension, the osmotic fragility of erythrocytes was not significantly different from that of normotensive controls without family history of hypertension. The membrane fragility had no correlation with the level of blood pressure or dietary salt intake. Thus, the osmotic fragility of erythrocytes might reflect functional or structural abnormalities of cell membranes, and could be one of the genetic markers of the hypertensive predisposition.

Adult↗
PubMed1984

Alteration of presynaptic alpha 2-mediated inhibition of norepinephrine release in perfused mesenteric arteries of young and adult spontaneously hypertensive rats.

The present study was designed to evaluate norepinephrine release during sympathetic nerve stimulation and its inhibitory characteristics by presynaptic alpha 2-adrenoceptor in the perfused mesenteric arteries of young and old spontaneously hypertensive rats (SHR) compared with age-matched Wistar-Kyoto rats (WKY). Sympathetic nerve stimulation caused significantly greater overflow of endogenous norepinephrine from adrenergic nerve terminals in young SHR than age-matched WKY. Yohimbine, alpha 2-adrenoceptor antagonist, exerted a facilitatory effect on norepinephrine overflow from mesenteric vasculature. This effect was less in young SHR than in aged-matched WKY. On the other hand, in adult SHR the amount of norepinephrine overflow was somewhat reduced compared with age-matched WKY. The difference of the facilitatory effect on norepinephrine overflow by yohimbine between SHR and WKY was not so marked as that observed in young age. These results indicate that increased norepinephrine release from sympathetic nerve endings in young SHR could depend at least partly on impaired presynaptic alpha 2-mediated inhibition, while normal or reduced norepinephrine release in adult SHR might be an adaptive mechanism to prevent further increase in blood pressure in SHR.

Aging↗
PubMed1984

Deoxyribonucleoside-3',5'-cyclic silanediyl derivatives: formation and properties.

Formation of 3',5'-O-(dialkylsilanediyl)deoxyribonucleosides was studied. Treatment of deoxythymidine in DMF with bifunctional silylating reagent such as di-t-butyldichlorosilane and diisopropyldichlorosilane in the presence of imidazole gave the expected silanediyl derivatives. The structure was confirmed mainly by NMR spectroscopy. The stability of these cyclic silyl derivatives toward hydrolysis is also described.

Deoxyribonucleosides↗
PubMed1984

Circulating levels of vitamin D metabolites in patients with hyperinsulinaemia.

Circulating levels of vitamin D metabolites were studied in hyperinsulinaemic patients with insulinoma or insulin autoimmune syndrome. Plasma ionized calcium, parathyroid hormone, and 24,25-dihydroxyvitamin D (24,25(OH)2D) levels were not statistically different from controls, but the 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D) levels were significantly decreased in these patients, compared to controls (P less than 0.01 and P less than 0.05, respectively). However, the ratio of 24,25(OH)2D to 25(OH)D and that of 1,25(OH)2D to 25(OH)D in hyperinsulinaemic patients were significantly higher (P less than 0.01) than in controls. These results suggest that there may be alterations of vitamin D metabolism in the endogenous hyperinsulinaemic state.

Adult↗