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Biomedical subjects

M Kadoya

Publications and source records attributed to M Kadoya.

At least 109 records · Page 6Linked to original sources
PubMed1986

Hepatic artery embolization of experimental hepatic tumors with absolute ethanol.

Hepatic artery embolization with absolute ethanol (HAEE) was done in rats and rabbits with experimentally induced liver tumors, and its effects on liver parenchyma and tumors were analyzed microscopically in comparison with those of controls. HAEE with 0.1 ml in rats brought massive tumor necrosis and minimal damage to liver parenchyma. But HAEE with 0.15 ml in rabbits induced moderate to massive necrosis of liver parenchyma with minimal to moderate tumor necrosis. Damage to the intrahepatic bile ductules was also seen in both animals. Many problems should be resolved before clinical use.

Animals↗
PubMed1985

Unusual portosystemic collateral penetrating the liver parenchyma.

We present a case of an extremely rare portosystemic collateral pathway which arose from the right intrahepatic portal vein, passed through the liver parenchyma, and terminated into the inferior vena cava. We demonstrate the findings of diagnostic imaging and discuss the etiology of the collateral circulation in this unusual case.

Aged↗
PubMed1985

201Tl per-rectal scintigraphy in primary hepatocellular carcinoma.

The results of 201Tl per-rectal scintigraphy in 10 patients with primary hepatocellular carcinoma (HCC) were presented together with the findings from contrast angiography, computed tomography and ultrasonography. 201Tl accumulation within the tumour was seen in seven of ten patients. This accumulation was thought to be due to 201Tl supply not from the portal vein but from the hepatic artery since significantly high heart to liver uptake (H/L) ratio from 0.71 to 1.21 and clear visualization of the heart and kidneys, indicating the presence of abundant portal-to-systemic shunting, were observed. Another three patients showed negative 201Tl accumulation within the tumour and near-normal H/L ratios from 0.32 to 0.47 which indicates little portal-to-systemic shunting. This finding reveals the evidence of the lack of 201Tl supply to the tumour from the portal vein. It seems that HCC does not receive any significant amount of blood flow from the portal system.

Administration, Rectal↗
PubMed1984

Segmental staining on hepatic arteriography as a sign of intrahepatic portal vein obstruction.

Peripheral obstruction of intrahepatic portal vein branches was detected by dynamic sequential computed tomography during arterial portography and subsequently confirmed surgically in 9 patients with hepatic neoplasm (7 hepatocellular carcinomas, 1 cholangiocarcinoma, and 1 metastatic lymphadenopathy from gastric carcinoma). In 1 patient, 2 obstructed segments were seen. Eight of these 10 segments showed more dense staining than other regions of the liver during infusion hepatic angiography. Retrograde opacification of the peripheral venules of the obstructed portion was seen in 2 of these 8 segments. This pattern was attributed to trans-sinusoidal or peripheral arterioportal shunting. In 5 cases, the segmental staining obscured the tumor stain, making the tumor appear larger than it actually was or causing it to be missed altogether.

Adenoma, Bile Duct↗
PubMed1983

Work in progress: dynamic sequential computed tomography during arterial portography in the detection of hepatic neoplasms.

Dynamic sequential computed tomography with table incrementation during arterial portography (DSCTI-AP) of the entire liver was performed in an attempt to improve the detection of hepatic neoplasms. In 13 of 17 patients, DSCTI-AP detected more hepatic lesions than were detected by other imaging methods, including radionuclide liver scans, ultrasound, computed tomography, and hepatic angiography. In only one case, an extremely hypervascular hepatocellular carcinoma, hepatic angiography was superior to DSCTI-AP. DSCTI-AP is a simple technique that may be carried out as a part of hepatic angiography. We believe that DSCTI-AP is a sensitive and useful method for the accurate detection of hepatic neoplasms.

Angiography↗
PubMed1983

Electrophysiological effects of nicardipine hydrochloride on the isolated sinoatrial and atrioventricular nodes of the rabbit.

The electrophysiological effects of nicardipine-HCl, a new calcium antagonist and potent vasodilator, were studied in the isolated sinoatrial (SA) and atrio-ventricular (AV) nodes of the rabbit in an oxygenated Tyrode solution at 35 degrees C using an intracellular microelectrode technique. Nicardipine-HCl decreased the spontaneous rate of the SA node and prolonged sinus recovery time, dose-dependently. The effective refractory period (ERP) and functional refractory period (FRP) of the AV node and AV conduction time (A-H interval) were also prolonged by nicardipine-HCl in a dose-dependent manner. In conclusion, nicardipine-HCl has electrophysiological effects on the SA and the AV node similar to those of other calcium antagonists in the excised and superfused rabbit heart.

Animals↗
PubMed1982

Electrophysiological effects of disopyramide on hypoxic rabbit ventricular muscle.

Intracellular microelectrode recording techniques were used to elucidate the mechanism of the antiarrhythmic action of disopyramide in an isolated rabbit ventricular muscle perfused by hypoxic Tyrode's solution. Hypoxia induced no significant changes of the resting membrane potential or action potential amplitude but decreased the maximum upstroke velocity of the action potential (dV/dt max) and shortened the action potential duration and the effective refractory period. Disopyramide in a dose of 5 microgram/ml induced a significant decrease of resting membrane potential and action potential amplitude of hypoxic muscle while it did not alter these parameters in oxygenated muscle. Disopyramide depressed dV/dt max in hypoxic muscle as well as in oxygenated muscle. However, there was much greater depression in hypoxic cells. After disopyramide, action potential duration at the 90% level of repolarization and the effective refractory period were prolonged in both hypoxic and oxygenated ventricular muscle. However, disopyramide lengthened the effective refractory period of hypoxic muscle to a much greater degree than that of oxygenated muscle. This resulted in a decrease of disparity in refractoriness. The above differential effects of disopyramide in oxygenated and hypoxic tissue may account for its effectiveness in postinfarction re-entrant arrhythmias.

Action Potentials↗