Search PubMed⌕ Search

Biomedical subjects

M Itoh

Publications and source records attributed to M Itoh.

At least 1,135 records · Page 63Linked to original sources
PubMed1979

Effects of thyroidectomy on monoamine oxidase activities toward tyramine and serotonin in the circumventricular nuclei of the rat.

Following thyroidectomy, monoamine oxidase (MAO) activities toward tyramine decreased significantly by 20% in the nucleus periventricularis and the nucleus arcuatus among the 3 hypothalamic nuclei of the rat, while MAO activity toward serotonin decreased significantly by 10% only in the nucleus periventricularis. It is suggested that thyroidectomy induced selective changes on the multiple forms of MAO in the discrete circumventricular nuclei.

Animals↗
PubMed1979

A computer-aided three-dimensional display system for ultrasonic diagnosis of a breast tumour.

This paper describes a three-dimensional (3-d) display method by which the shape of an abnormal tissue, say, a breast tumour is represented as a line picture on a cathode ray tube (crt). The 3-d image consists of a set of overlaid contour lines, each of which shows the boundary of the tissue and is obtained from the corresponding B-scan digitized image by using image processing techniques such as smoothing and Laplacian. The system together with the 3-d algorithm is explained and some of the experimental results and pertaining problems are discussed.

Beta Particles↗
PubMed1979

Effect of 5-hydroxytryptamine on blood glucose and cyclic AMP in the rat.

The effects of 5-hydroxytryptamine (5-HT) on plasma cyclic AMP (cAMP) and glucose concentrations were studied in rats in vivo. 5-HT injected i.p. increased plasma cAMP and glucose. Injections of propranolol, hexamethonium, and cyproheptadine inhibited the 5-HT-induced increase in glucose but not in cAMP. Atropine did not inhibit the action of 5-HT. These effects of 5-HT were not seen in adrenomedullectomized rats, and 5-HT did not elevate the concentration of plasma cAMP in anti-glucagon antiserum-injected rats. These results confirm the previously reported finding that 5-HT-induced increase in blood glucose is mediated via adrenaline released from adrenal medulla by 5-HT and suggest that the increase in plasma cAMP, induced by 5-HT, is due to glucagon released by an unknown factor, or factors other than adrenaline released from the adrenal medulla by 5-HT.

Adrenal Medulla↗
PubMed1979

Immunoreactive somatostatin in the hypothalamus and other regions of the rat brain: effects of insulin, glucose, alpha- or beta-blocker and L-dopa.

Effects of various hormonal and pharmacological manipulations on somatostatin distribution were investigated to elucidate the physiological significance of somatostatin in the hypothalamus and the other regions of the rat brain. Immunoreactive somatostatin (IRS) was measured by radioimmunoassay newly developed. Insulin induced an increase of hypothalamic IRS and a decrease of plasma RGH, while glucose administration resulted in the opposite responses, which were not significant. Insulin also increased IRS in the thalamus and the brain stem. The insulin-induced increase of hypothalamic IRS was reduced by hyperglycemia. Glucagon reduced IRS initially and then increased it with an elevation plasma RGH. L-dopa did not affect hypothalamic IRS, although it decreased plasma RPRL. Phentolamine slightly increased plasma RGH and decreased IRS in most regions of the rat brain, while propranolol increased IRS in these regions. Pretreatment with propranolol significantly increased plasma RGH 120 min after insulin administration, and hypothalamic IRS decreased initially by pretreatment with propranolol, and then it increased significantly. When pretreated with propranolol, glucagon markedly increased plasma RGH and decreased IRS significantly. From these findings it is concluded that hypothalamic IRS may participate in the hormonal regulatory system in correlation to plasma RGH, as observed in studies on plasma GH and hypothalamic IRS following insulin, glucose, propranolol or phentolamine administration, but IRS in other regions of the brain may have some other actions as a neurotransmitter or a modulator, because of no significant correlation between plasma GH or PRL and IRS in these regions following various stimuli. In addition, glucose homeostasis and adrenergic mechanism may be important factors in regulating IRS in the rat brain.

Adrenergic alpha-Antagonists↗
PubMed1979

Effect of renal vein ligation with or without suprarenal inferior vena cava ligation on sodium and phosphate excretions during acute extracellular volume expansion in the rat.

Right nephrectomy with or without inferior vena cava (IVC) ligation was performed in rats 1 week after left renal vein ligation. Left kidney function and sodium and phosphate excretions by volume expansion were investigated. Inulin (CIN) and para-aminohippuric acid (CPAH) clearances and fractional excretions of sodium (FENa) and phosphate (FEP) were examined before and after volume expansion was induced by normal saline. Kidney functions were well preserved with development of collateral venous channels; biochemical parameters returned to the normal ranges. However, CIN and CPAH were reduced to 33 to 25 per cent of control values and the filtration fraction was elevated. After volume expansion, a marked increment of FENa was observed in cases of IVC ligation but the increment in animals without IVC ligation was less than in the control group. FEP was also increased in experimental groups but the magnitude of phosphaturia was not so prominent compared to the control group. The increment of FEP was not comparable to that of FENa. Thus, from the aspect of kidney function, this experiment showed the rationality of left renal vein ligation with contralateral nephrectomy. From the pathophysiologic aspect, the magnitude of natriuresis and phosphaturia by volume expansion was not prominent and a reduced reabsorptive capacity for sodium and phosphate may exist in a solitary kidney with a ligated renal vein. When suprarenal IVC ligation was also done, prominent natriuresis was observed with saline infusion.

Animals↗