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Biomedical subjects

M Hashizume

Publications and source records attributed to M Hashizume.

At least 181 records · Page 10Linked to original sources
PubMed1986

Patterns of pannus growth of the expanded polytetrafluoroethylene vascular graft with special attention to the intimal hyperplasia formation.

Serial histologic observations of the healing process of expanded polytetrafluoroethylene (PTFE) vascular grafts in dogs were performed. The common iliac arteries of 12 mongrel dogs were replaced with a 2-cm segment of 6 mm PTFE graft, bilaterally. The grafts were studied microscopically after the animals were killed at 4, 8, 12, 16, 20, and 24 weeks. All the grafts remained patent up to 24 weeks. Special attention was paid to the histological characteristics of pannus growth, which were divided into two types: smooth appearing and irregular. The former type was characterized by smooth, thinner connective tissue growth along the graft, and the latter was defined as irregular-shaped pannus containing large and small thrombi. Only pannus of the smooth type showed similar growth patterns and growth rates. These findings suggest essentially that pannus develops smoothly from both ends of the graft; however, thrombi disturbed this growth pattern. In 24 grafts, eight nodular lesions of the pannus (greater than 500 mu in height) were found: five distally and three proximally. All eight lesions were found within 3 mm of the anastomoses. Among these eight lesions, five were on the completely healed pannus, and the remainings were all on the irregular pannus. This suggests that thrombi organization followed by nodular lesions are major offending factors that lead to the formation of intimal hyperplasia.

Animals↗
PubMed1985

Hyperdynamic circulation in the left gastric venous area in patients with portal hypertension: angiological assessment.

The time of appearance of the left gastric vein on serial celiac arteriograms in patients with portal hypertension and esophageal varices was compared with that of the portal vein to assess regional hemodynamics in the left venous portion of the stomach, an area located in close proximity to the varices. In two thirds of all the patients with cirrhosis or non-cirrhotic idiopathic portal hypertension (IPH), the left gastric vein was visualized earlier or simultaneously than or with the portal vein, while in all but one patient with prehepatic portal obstruction, there was a delayed opacification of the left gastric vein. These results suggest the presence of a hyperdynamic circulatory state which promotes venous hypertension in the left gastric venous area of the stomach of a considerable number of patients with cirrhosis or IPH. In such a hemodynamic state, selective decompression of varices can be achieved by a left gastric venous caval shunt.

Esophageal and Gastric Varices↗
PubMed1985

The role of prostacyclin in patients with portal hypertension.

The serum levels of prostacyclin in portal venous blood samples from patients with portal hypertension were measured by radioimmunoassay to assess the role of prostacyclin in this clinical entity. Portal venous prostacyclin activity exceeded peripheral venous activity 2-3 fold in both cirrhotics and non-cirrhotics. The size of esophageal varices showed an inverse relation to the concentration of portal venous prostacyclin in the cirrhotics. There was no significant difference between the portal vein pressure and the size of varices, and the portal vein pressure did not correlate with the concentration of 6 keto-PGF1 alpha. Thus, serum levels of portal venous prostacyclin may depend on the development of collateral circulation in cirrhotics and increased splanchnic blood flow probably accelerates the washout effect.

Adult↗
PubMed1984

Exclusion of nonisolated splenic vein in distal splenorenal shunt for prevention of portal malcirculation.

In an attempt to prevent portoprival malcirculation after distal splenorenal shunt (DSRS), a splenic hilar renal shunt (HRS) with proximal flush ligation of splenic vein was designed. To accomplish this procedure, two methods were compared: HRS alone (Group A) and HRS plus proximal flush ligation of the splenic vein (Group B). In Group A, which included 20 cirrhotic patients with esophageal varices, angiographic as well as pulsed Doppler flowmetric follow-up study revealed a portal thrombosis in two patients and severe narrowing of a portal vein in another two. Considerable stealing flow was observed in these four patients. In the Group B series, which included 33 cirrhotic patients, there were no gross changes in the portal hemodynamics. Normal prograde portal flow was confirmed by Doppler flowmeter in this series including 14 patients of more than 8 months after surgery. When the amount of nonisolated splenic vein embedded in the pancreas is minimized, portal malcirculation after distal splenorenal shunt can, to a great extent, be prevented.

Collateral Circulation↗
PubMed1984

The natural history of non-alcoholic cirrhosis.

To assess the natural history of non-alcoholic liver cirrhosis, one hundred and eighty medically treated Japanese cases, including 110 accompanied by esophageal varices were investigated retrospectively. Among those patients with varices fifty-one (46.4%) bled from the upper gastrointestinal (GI) tract and thirty-two (29.1%) from esophageal varices, while GI bleeding was found in only six out of 70 patients without varices. The GI bleeding rate was the highest in patients with varices and concomitant hepatoma (76.5%). The mortality rate of the GI bleeders was 68.6% in patients with varices and 33.3% in patients without varices. The mortality on the first variceal bleeding episode was 65.6%, and another 25.0% had rebleeding from varices, resulting in a one-year survival of 9.4%. The ten-year cumulative percentage of variceal bleeding was 61.2% in patients with varices, and that of occurrence of hepatoma was 50.7% in total of 180 patients. This study revealed that the non-alcoholic cirrhotic patients have a highly rate of complication by hepatoma and that the development of hepatoma doubles the risk of varix rupture.

Adult↗
PubMed1978

Experimental studies and clinical report on the electrical alternans of ST segment during myocardial ischemia.

During myocardial ischemia produced in 43 dogs by occlusion of left coronary artery, electrical alternans developed in 34 experiments. The most common was alternans of ST-T complex. Surface and intracellular electrograms were recorded simultaneously from contiguous sites in the ischemic area. The alternans of ST-T complex in the surface electrogram corresponded to that of the rate of repolarization of the membrane action potential. The development of this alternans is localized in 2 relatively small area and transient. This may be the reason why electrical alternans of ST-T is clinically rare. A clinical case showing electrocardiographic changes of electrical alternans of ST-T complex without any change in the QRS complex is reported. Myocardial infarction and hypokalemia is considered as a cause of the alternans. The present results support the hypothesis that the mechanism of electrical alternans will be an alternation of the rate and extent of the ions transported across the myocardial cell membrane.

Aged↗