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Biomedical subjects

T Sano

Publications and source records attributed to T Sano.

At least 829 records · Page 46Linked to original sources
PubMed1976

Selective depleting effect of syrosingopine on brain catecholamine levels with relation to morphine analgesia in the rat.

Reserpine was the most potent, rescinnamine the next and syrosingopine the weakest in the depleting effects on brain amines of rauwolfia alkaloids. After syrosingopine, brain dopamine (DA) was decreased to a smaller degree and with a shorter duration as compared with norepinephrine (NE) and serotonin (5-HT), whereas reserpine elicited a marked and long lasting reduction in these amines. Accordingly, syrosingopine induced a depletion of brain NE and 5-HT without alteration in brain DA content 2-4 days after administration. Repeated administrations of syrosingopine, 2 mg/kg daily for 2 or 4 days, resulted in similar alterations in brain amine levels. This selective depleting effect of syrosingopine on brain amines was potentiated by combined treatment with disulfiram or fusaric acid, a dopamine beta-hydroxylase inhibitor. Under the condition of selective depletion of brain amines induced by repeated administrations of syrosingopine, 2 mg/kg daily for 2 days, the analgesic action of morphine was not affected, whereas reserpine and tetrabenazine antagonized morphine analgesia, concomitant with inducing a depletion of all brain amines. The results suggest that brain DA may be more important than brain NE or 5-HT with regard to the mechanisms by which morpine produces analgesia.

Analgesia↗
PubMed1976

Electrical alternans of TU wave in Romano-Ward syndrome.

A case is presented in which an exceptional electrical alternans of the TU wave occurred in association with the Romano-Ward syndrome. This appears to be the first reported example of this association. Ventricular fibrillation was documented during the syncopal attacks. There was no evidence of abnormality of the serum electrolytes.

Aged↗
PubMed1976

Role of sinoatrial ring bundle in internodal conduction.

The role of the sinoatrial ring bundle (SARB) in internodal conduction was examined by the microelectrode technique in excised rabbit hearts. The spread of the sinus impluse to the surrounding tissues was shown to proceed anteriorly toward the right branch of the crista terminalis significantly faster than toward the other direction. Thus the right SARB and the right branch of the crista terminalis close to the sinus node were the earliest areas excited by the sinus impulse in the areas surrounding the sinus node. It was further shown that the activation sequence does not initiate from the right SARB to the right branch of the crista terminalis via the junction of these two structures. Cutting the SARB did not produce any delay in conduction from the sinus node to the atrioventricular (AV) node. The conduction velocity measured at the endocardial surface by two microelectrodes has proved that conduction in the crista terminalis was significantly faster than in the SARB. The upstroke of the action potential from the crista terminalis was also steeper than that from the SARB. These results suggest that the SARB is not the main route for impulse propagation from the sinus node to the AV node; the fastest internodal conduction therefore takes place with wide wave fronts, along the crista terminalis.

Action Potentials↗
PubMed1976

Role of slow inward current in the genesis of ventricular arrhythmia.

Action potentials of premature beats in ventricular muscle fibers showed a transient prolongation of duration as well as an increase in second depolarization of the plateau phase when the preceding diastolic intervals were progressively shortened. These changes were abolished by manganese ions. Voltage clamp experiments also disclosed a transient increase in slow inward current in premature excitations, of which time course was very similar to that in action potential changes. These results suggested that prolongation of action potential durations was mainly brought about by changes in slow inward current and this was partly related to the characteristics of recovery from inactivation of this current. An increase of slow inward current produced depressed conduction on the subsequent beat and it also shared the effects to extend the areas of slow response. These effects may accelerate the occurrence of re-entry.

Action Potentials↗
PubMed1976

Precancerous changes in the stomach.

Intestinal metaplasia is often associated with human gastric carcinoma. Intestinalization seems to be a typical example of abnormal differentiation and is possibly a precancerous state. For investigation of intestinal metaplasia, a method for visualizing disaccharidases using Tes-Tape was developed; this method was applied to many specimens of stomach surgically removed for the treatment of gastric carcinoma. More than 130 specimens of human stomach were investigated. Intestinalization was classified into types I and II intestinal metaplasia. In type I intestinal metaplasia, sucrase, maltase, trehalase, alkaline phosphatase, goblet cells, and Paneth cells were present; while the type II intestinal metaplasia, sucrase and maltase were present but alkaline phosphatase and trehalase were absent. In type II, goblet cells were present but not Paneth cells. The histochemical technique for sucrase was newly devised. Some of the villi with goblet cells in the area of intestinalization in the stomach were not stained by sucrase activity, although most of the villi were stained. The presence of a third type of metaplasia was suggested. Purified sucrases obtained from the intestine and one case of type I intestinal metaplasia showed blood group reactivity due to the oligosaccharide side chain. However, purified sucrases obtained from two cases of type II intestinal metaplasia were negative in blood group reactivity. A close relation between distribution of alpha-fetoprotein and carcinoembryonic antigen in gastric carcinoma and that in surrounding intestinal metaplasia is discussed.

Carcinoembryonic Antigen↗