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Biomedical subjects

M Ito

Publications and source records attributed to M Ito.

At least 37 records · Page 2Linked to original sources

Effect of tolbutamide on plasma catecholamine in insulin dependent diabetics.

In 4 cases of insulin dependent diabetics, blood levels of glucose, C-peptide reactivity (CPR), free fatty acid, and catecholamines were followed after the intravenous tolbutamide response test. Plasma CPR was low and did not respond to tolbutamide injection, and blood levels of glucose and free fatty acid did not change during the test. Fifteen min after the tolbutamide injection, plasma epinephrine plus norepinephrine and norepinephrine levels fell to 87.5% and 67.4% of the initial values, respectively. These results suggest that decrease in the blood glucose and free fatty acid levels usually observed after tolbutamide injection is not the direct action of drug, but is secondary to insulin secretion, and tolbutamide-induced decrease in catecholamines may contribute to the secretion of insulin from the pancreatic beta-cells.

Catecholamines

Significance of skin pressure in body heat balance.

It has been demonstrated by Takagi and his colleagues that pressure on a specified area of the body surface causes depression of sweating in a certain body division and changes in the relative sweat rates between body divisions. Furthermore, skin pressure has been assumed to suppress the central thermoregulatory activity, thus bringing about a rise or fall in body temperature in a hot or cool environment, respectively. We examined the effect of skin pressure applied to the bilateral subaxillary regions on body heat balance by means of continuous recordings of evaporative weight loss (total sweat rate), local sweat rates at various areas and rectal and skin temperatures and measurements of metabolic rate. Most experiments were carried out at a room temperature of 36 degrees C with 40% rh and a few were done at 27 degrees C in the absence of thermal sweating. Various strengths of pressure up to 5 kg/50 cm2 were employed. It was observed that the total sweat rate was either unchanged, decreased or occasionally even increased. There was an apparent tendency that the stronger the pressure was, the more depressed was the total sweating. A weaker pressure, on the other hand, often caused facilitation of total sweating. Changes in rectal and mean body temperatures and in metabolic rate were minimal in the majority of cases, and bore no relationship to the changes in the total sweat rate. These results offer no evidence that skin pressure of up to 5 kg/50 cm2 affects human central thermoregulatory activity but suggest that it may exert a sweat-inhibitory effect, primarily through the interaction of sudomotor impulses somewhere along the efferent pathways, possibly at the spinal segmental level.

Adult

[Automatic rearing system of mice and transmission of pseudomonas aeruginosa].

Mice either excreting or not excreting Pseudomonas aeruginosa in feces were maintained in stainless steel mesh cages on an automated rearing apparatus with automatic water-supply nozzles and intermittently flusing metal racks. No evidence of transmission of the organisms from positive mice to negative ones was obtained during at least eight weeks.

Animals

[Pharmacological studies on experimental nephritic rats (6). Antinephritic effects of sodium chondroitin sulfate and other drugs on modified type of Masugi's nephritis].

Using the modified model of Masugi's nephritis in rats, the antinephritic effects of sodium chondroitin sulfate (CS) and other drugs were evaluated by determining the biochemical parameters in urine, serum and renal cortex as well as light microscopic observation in kidneys by preventive and curative tests. In the preventive test where drug treatment was initiated at the same time as the injection of anti-kidney serum, CS (200 mg/kg p.o.) was effective in reducing serum triglyceride level, but was ineffective against other parameters. In the curative test where drug treatment was given from the 10th day after the induction of nephritis, CS (200 mg/kg p.o.) resulted in reductions of urinary excretions of protein and enzymes such as alkaline phosphatase and N-acetyl-beta-glucosaminidase, the inhibition of urinary fibrinolytic activity and reduction in levels of serum cholesterol and triglyceride. Moreover, histological examination indicated a significant reduction of the index of glomerular lesions by the treatment of this drug. Of other drugs, dexamethasone (0.1 mg/kg p.o.) was effective in both tests, while warfarin potassium (0.05 or 0.1 mg/kg p.o.) exerted a beneficial effect only in the preventive test. From these results, the effectiveness of CS in the curative test is probably due to promotion of healing of damaged tissue in the kidneys.

Adrenochrome

Effects of ascorbic acid and sodium ascorbate on cyclic nucleotide metabolism in human lymphocytes.

L-ascorbic acid (LAA) augmented cGMP many-fold in highly purified human peripheral blood lymphocytes. The cGMP response occurred within 10 sec and persisted for at least 60 min. D-ascorbic acid (DAA) and dehydroascorbic acid (DHAA) were also equally active in enhancing cGMP concentrations but metabolic precursors of ascorbic acid and other inorganic acids did not increase cGMP levels. Determination of the amount of DHAA contaminating the LAA precluded the possibility that it was solely responsible for the enhanced cGMP levels. The sodium or calcium salts of ascorbic acid did not increase cGMP concentrations. If these neutralized preparations were acidified, increased cGMP concentrations were then noted. In broken cell preparations, LAA, DAA, and DHAA and to a lesser extent sodium ascorbate (NaA) enhanced guanylate cyclase activity while neither inhibited cAMP or cGMP phosphodiesterase (PDE) activity. The possible role of H2O2, fatty acid liberation, prostaglandin production, oxidizing-reducing agents, and free radical formation in mediating the effects of ascorbic acid on cGMP levels were evaluated, but none of these potential mechanisms were definitively proven to be a required intermediary for the cGMP enhancing activity of ascorbic acid. LAA, DHAA or NaA did not induce lymphocyte transformation or modulate lectin-induced mitogenesis.

2',3'-Cyclic-Nucleotide Phosphodiesterases