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Biomedical subjects

Y Katano

Publications and source records attributed to Y Katano.

At least 91 records · Page 5Linked to original sources
PubMed1976

[Experimental anti-arrhythmic effects of a new beta-adrenergic receptor blocking agent, dl-l-(tert. butylamino)-3-[(2-propinyloxy)phenoxy]2-propanol hydrochloride (dl Kö 1400-Cl)].

Antiarrhythmic property of a new adrenergic beta-blocking agent, dl-1-(tert.butylamino)-3[(2-propinyloxy) phenoxy]-2-propanol hydrochloride (Kö 1400-Cl) was studied, using 1) ouabain-induced arrhythmia in the guinea pig, 2) aconitine-induced arrhythmia in the rat, 3) arrhythmia induced by two-step ligation of coronary artery (Harris's method) in the dog and 4) halothane-adrenaline arrhythmia in the dog and was compared with those of propranolol, oxprenolol, procainamide and ajmaline. Procainamide and ajmaline produced a marked protective effect against aconitine-induced ventricular extrasystole, but were not so effective against aconitine-induced ventricular fibrillation, while oxprenolol and, to a lesser degree, propranolol were effective against the latter type of aconitine arrhythmias. Kö 1400-Cl proved to be ineffective. All the compounds tested produced a marked protective action against ouabain-arrhythmia. Whereas procainamide was most effective in abolishing the ventricular arrhythmia due to coronary-ligation even on the first postoperative day, Kö 1400-Cl and propranolol were almost ineffective on the first day. Even on the second postoperative day, the antiarrhythmic effects of these two beta-blockers were not remarkable, effective only in 2/4 animals in the case of Kö 1400-Cl and in 2/3 animals in the case of propranolol. On the contrary, all the beta-blockers tested produced a protective action against halothane-adrenaline arrhythmia at much lower doses than against coronary ligation arrhythmia. The potency ratio of Kö 1400-Cl and propranolol was 3 : 1, which paralleled with beta-blocking activity of these compounds.

Aconitine↗
PubMed1975

[Assay of cardiotonic steroids based on a 2-compartment model].

In an attempt to develop an assay method for cardiotonic steroids (CS), a two compartment model was applied to the whole dog. As representative CS, g-strophanthin, digoxin and digoxigenin were infused continuously to the animal, and the minimal cardiotonic, irregularity and lethal doses were determined, together with indices K1 and K2, representing the rate of uptake and elimination, respectively, of these compounds into and out of a specific site within the myocardium. The order of cardiotonic potency was: g-strophanthin greater than digoxin greater than digoxigenin. The indices K1 (and K2) were the greatest with digoxigenin )digoxigenin), the second greatest with g-strophanthin (digoxin) and the smallest with digoxin (g-strophanthin). The order of the margin of safety as a ratio between the minimal irregularity and the minimal cardiotonic doses was: digoxin greather than g-strrophanthin greather than lethal and the minimal cardiotonic doses. The cardiotonic, irregularity and lethal doses obtained in the present study coincided well with the values obtained in the canine heart-lung preparations, thus lending further support to the idea that effects of the CS appear when the substances accumulated to a definite amount at a specific site within the myocardium.

Animals↗
PubMed1975

Coronary vasodilatation and adrenergic receptors in the dog heart and coronary.

The question of whether the coronary blood vessels contain an intrinsic adrenergic mechanism for vasodilatation of physiological significance has been examined in the canine heart-lung preparation with a donor by studying the response of the coronary vessels to epinephrine, norepinephrine, isoproterenol and salbutamol in combination with practolol. To differentiate the vasodilatation mediated through adrenoceptors in the coronary vessels from that resulting from an increase in the myocardial O2 consumption, a special method of analysis was developed based on the linear relation between the coronary flow and the myocardial O2 consumption. It was found that all four compounds produced an increase in the coronary flow attributable to an increased myocardial O2 consumption. Epinephrine and norepinephrine produced a decrease in the coronary flow after practolol which completely abolished the increase in the myocardial O2 consumption as well as the positive inotropic and chronotropic effects produced by these compounds, while isoproterenol and salbutamol produced an increase. These results indicate that adrenergic beta-receptor exists in the coronary subserving a vasodilatation. However, the vasodilatation through this mechanism is of minor importance under physiological conditions and becomes completely masked in the presence of an overwhelmingly strong vasodilatation consequent to an increase in the myocardial O2 consumption.

Albuterol↗
PubMed1975

Effects of ethyl adenosine-5'-carboxylate on the heart and coronary circulation.

Using the canine heart-lung preparation supported by a donor, the effects of ehtyl adenosine-5'-carboxylate (EAC) on the heart and coronary circulation were studied and compared with those of adenosine. EAC produced qualitatively similar effects to adenosine in this preparation. Aminophylline inhibited the effects of EAC as well as those of adenosine. Dipyridamole did not potentiate the effects of EAC, while it produced a definite potentiation of the effects of adenosine.

Adenosine↗
PubMedDate not supplied

TT virus (TTV) is not associated with acute sporadic hepatitis.

A novel virus, TT virus (TTV), recently discovered by Okamoto et al. in the serum of a patient with posttransfusion hepatitis, is thought to be one of the causative agents of blood-borne acute hepatitis. The association of this virus with acute sporadic hepatitis was evaluated. TTV DNA was detected in 4 (4.9%) of 81 cases of acute hepatitis A, in 5 (16.7%) of 30 cases of acute hepatitis B, in 1 (25.0%) of 4 cases of acute hepatitis C, in 1 (9.1%) of 9 cases of cytomegalovirus and Eppstein-Barr infection, and in 8 (13.6%) of 59 cases of acute hepatitis of unknown etiology. These positive rates of TTV in various etiologies did not differ significantly amongst each other, and were similar to those of healthy volunteers, i.e. 12.0% (12/100). The comparison of levels of alanine aminotransferase, aspartate aminotransferase, total bilirubin, hepaplastin test and prothrombin time between TT virus-positive and -negative patients did not show any differences. This indicates that TTV is neither a main causative agent of acute sporadic hepatitis of unknown etiology, nor does it affect the clinical features of acute hepatitis with already known etiology.

Acute Disease↗
PubMedDate not supplied

Effects of l- and d-propranolol on the ischemic myocardial metabolism of the isolated guniea pig heart, as studied by 31P-NMR.

Using 31P nuclear magnetic resonance (NMR) spectroscopy (acquisition time of 3 min), we studied the effects of l- and d-propranolol on the ischemic derangement of myocardial energy metabolism in the isolated perfused guinea pig heart. The myocardial pH and concentration of high-energy phosphate were used as measures of the energy metabolism. Cardiac pH progressively declined during ischemia from 7.41 +/- 0.04 to 7.13 +/- 0.05, 6.91 +/- 0.04, 6.74 +/- 0.04, and 6.61 +/- 0.04 (before ischemia and 3, 6, 9, and 12 min after ischemia, respectively). After 3 min of reperfusion, pH rapidly returned to 7.42 +/- 0.04. Creatine phosphate (CP) and adenosine triphosphate (ATP) contents were reduced, while inorganic phosphate (Pi) contents were increased during ischemia. Whereas CP and Pi contents were restored to the normal values after reperfusion, the recovery of ATP contents was poor. Both l- and d-propranolol (10(-6) M) significantly suppressed the fall of the myocardial pH. Changes in the high-energy phosphate contents were also attenuated by l- and d-propranolol. These results suggest that not only l-propranolol, but also d-propranolol can produce beneficial effects on the ischemic derangements of myocardial energy metabolism.

Adenosine Triphosphate↗
PubMedDate not supplied

Detection of noradrenaline-immunoreactive nerve fibres in rat liver by immunoelectron microscopy.

Noradrenergic innervation of rat liver was studied immunohistochemically using antibody to noradrenaline at the electron-microscopic level. Noradrenaline-immunoreactive nerve fibres were located in the portal tract and some were in close contact with the portal vein and hepatic artery. Noradrenaline-immunoreactive fibres were found to contain many vesicles that were reactive to anti-noradrenaline antibody. This preliminary study suggests that the method for detecting noradrenaline-immunoreactive fibres using the antibody is useful for studies at the electron-microscopic level.

Animals↗
PubMedDate not supplied

The non-surgical treatments of hepatocellular carcinomas in a patient with severe hemophilia A.

We recently treated a patient with multiple hepatocellular carcinomas (HCC) who had severe hemophilia A and thrombocytopenia secondary to cirrhosis. He was not a candidate for surgery because of his liver failure. Transcatheter arterial chemoembolization and percutaneous ethanol injection therapy were successfully performed without complications by maintaining factor VIII levels above 40%. We believe that the non-surgical treatment of HCC can be performed safely in patients with coagulation disorders, by the appropriate administration of coagulation factors, despite thrombocytopenia and/or elongation of the prothrombin time from cirrhosis.

Adult↗