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Biomedical subjects

Y Nimura

Publications and source records attributed to Y Nimura.

At least 289 records · Page 16Linked to original sources
PubMed1991

[Coagula tamponade as a complication of open heart surgery: the clinical significance and diagnostic value of transesophageal echocardiography].

The pathogenesis of low cardiac output failure (LOF) immediately after open heart surgery was studied in 41 patients with LOF and 15 control patients without LOF using echocardiography. In 35 patients, transesophageal echocardiography was also performed. Left ventricular (LV) contraction was impaired in 28 of the 41 LOF patients, in whom LV fractional shortening was less than 25%. In the other 13 LOF patients, however, it was greater than 25%. In 12 of these 13 patients, transesophageal echocardiography revealed that accumulating pericardial coagula were localized in the right side of the heart, deforming the right atrial and ventricular chambers. The LV end-diastolic diameter was significantly less than the control, indicating that the pericardial coagula disrupted the distension of the heart. Emergent coagulotomy was performed in 5 patients, and hemodynamic conditions were improved. In spite of "cardiac tamponade", the wall motion and pressure tracings of the right atrium and right ventricle in these patients differed from those in fluid tamponade. Therefore, this condition should be designated "coagula tamponade." In the other 22 patients in whom transesophageal echocardiography was employed, no coagula were observed. Since pericardial coagula can hardly be detected by transthoracic echocardiography, transesophageal echocardiography is indispensable for diagnosing pericardial coagula noted immediately after open heart surgery.

Adult↗
PubMed1991

[Human heart recovery during weaning from a left ventricular assist system: time course and outcome prediction].

To investigate the time course of recovery of a failing heart using the left ventricular assist system (LVAS) and to predict the outcome of weaning from the LVAS, 14 patients with a failing heart were studied. Among them, 5 had recovered and survived for more than 2 weeks after weaning from the LVAS (recovered group), while 9 could not be weaned or died within 2 weeks after weaning (unrecovered group). All patients were gradually weaned from the LVAS with adequate support for systemic circulation for 3 days. In the recovered group, indices of systolic time intervals (STIs) showed improvement within a week. However, improvement of STIs was slow reaching a plateau around the 10th day in the unrecovered group. On weaning from the LVAS, aortic systolic pressure and ejection time were regulated by the patients' own hearts and were nearly the same between the 2 groups. However, left atrial pressure was significantly higher in the unrecovered group than in the recovered group. These hemodynamic features were first present on the 7th day. Therefore, hemodynamic data on the 7th assistant day can be a reliable factor in predicting the possibility of successful weaning from the LVAS and recovery in patients with a failing heart.

Adult↗
PubMed1991

[Management of cholangitis complicated in biliary carcinoma with hilar bile duct stenosis].

We reviewed 60 cases of biliary carcinoma with hilar bile duct stenosis which had received percutaneous transhepatic cholangio-drainage (PTCD). Of the 60 cases, nine were complicated with acute cholangitis (AC) and three with segmental acute obstructive suppurative cholangitis (S-AOSC). The incidence of cholangitis was 20%. Six patients with AC and three with S-AOSC underwent hepatic resection for carcinoma. As to preoperative management for cholangitis in these 9 cases, conservative chemotherapy was effective in only 2 cases, and additional PTCD or segmental introduction of the drainage catheter under PTCS were useful in 5 cases. The remaining 2 cases with S-AOSC needed urgent hepatic resection including suppurative hepatic segments after various interventional treatments. No significant difference was found in resectability, morbidity and mortality between the cholangitis group and non-cholangitis group. In conclusion, it is emphasized that postoperative outcome of biliary carcinoma with cholangitis will be improved by adequate PTCD and/or urgent hepatic resection.

Acute Disease↗
PubMed1991

[Efficacy of transesophageal echocardiography immediately after open heart surgery: diagnosis of coagula tamponade].

Massive pericardial coagula were detected by transesophageal echocardiography in some patients with low cardiac output failure immediately after open heart surgery. Characteristically, the coagula were localized anterior to the right atrium and right ventricle in all patients. The coagula could not be detected by transthoracic echocardiography. Despite of low output, absence of wall motion abnormality of the left ventricle, tachycardia, elevated atrial pressure and small left ventricular cavity lead to diagnose cardiac tamponade by pericardial coagula. Neither the right atrial nor the right ventricular wall showed collapsing motion except the area with pericardial effusion. Massive coagula in the anterior mediastinum produced similar clinical manifestation, but could be differentiated from pericardial coagula by echographic identification of the anterior pericardium. Pericardial coagula were also observed in patients with superior vena cava syndrome, but low right atrial pressure differentiated it from coagula tamponade. In all of the present patients, usual transthoracic echocardiography did not offer any sufficient images for diagnosing pericardial coagula. Transesophageal echocardiography was indispensable for detecting pericardial coagula soon after open heart surgery.

Adult↗
PubMed1991

[Cholangiographic studies on bile duct branches of the caudate lobe in resected cases with biliary tract carcinoma involving the hepatic hilus].

Diagnostic value of the cholangiography was studied for carcinoma of the biliary tract involving the hepatic hilus, and special attention was paid on the cholangiogram of the bile duct branches (B1) of the caudate lobe. Cholangiograms of B1 were compared with pathologic findings in 42 (27 bile duct carcinomas, 15 gallbladder carcinomas) of 43 cases of biliary tract carcinomas. Sixty-four of B1 in the 42 cases could be studied radiologically and histopathologically. The findings of the root of B1 were classified into 4 groups: group A, not stenotic; group B, short segmental stenosis; group C, long segmental stenosis and group D, poorly imaged. Carcinoma invasion was found in 6 of 18 of group B, and in 9 of 16 of group C. Carcinoma was confirmed near the root of B1 in the remaining 7 of the 16 group C. Carcinoma invasion was found in 20 of 21 of group D, and invasion was suspected in the remaining one. Carcinomas were found in the root of B1 in all cases of poorly imaged or long segmental stenosis of B1, and in 33% of short segmental stenosis of B1. Therefore caudate lobe resection should be performed for carcinoma of the biliary tract involving the hepatic hilus.

Adult↗
PubMed1991

Mechanism of adaptive increase of respiratory enzymes in rat liver mitochondria during obstructive jaundice.

In order to elucidate the response of mitochondria to obstructive jaundice, we have examined the effects of common bile duct ligation on rat liver mitochondria. Although oxidative phosphorylation, especially respiratory control, of mitochondria was disturbed after the ligation, specific enzymic activities and subunit contents of the respiratory enzymes in mitochondria were significantly increased one week after the ligation. The immunostain for ubiquinol-cytochrome c oxidoreductase confirmed the increase in the subunit amounts in hepatocytes. This increase was associated with the increase in specific contents of DNA in mitochondria. These results suggest that mitochondrial biosynthesis is stimulated during obstructive jaundice.

Animals↗
PubMed1991

[Trends of management of carcinoma of the biliary tract].

Trends of management of carcinoma of the biliary tract are described. Ultrasonography has made it possible to perform non-invasive and routine examination for biliary disorders and to find early cancer of the gallbladder. Moreover, endoscopic ultrasonography has enabled to make a differential diagnosis and a staging diagnosis. Percutaneous transhepatic cholangioscopy has been used as the most precise diagnostic procedure and peroral cholangioscopy has been introduced as a more convenient endoscopy. Although percutaneous transhepatic biliary drainage is considered to be hazardous and disadvantageous procedure in Western countries, it is essential in Japan where radical and extended operation are frequently performed. In Japan, major hepatectomies, pancreatoduodenectomy and/or combined resections of major vessels are aggressively adopted for advanced gallbladder cancers. However, such operations are still much dangerous and long-term survivors are few. Therefore, application of these extended operation for this advanced disease should be carefully re-examined. Various hepatectomies with caudate loberesection have been performed for patients with carcinoma of the hepatic hilus. Liver transplantation is also attempted for this disease, however, not accepted generally. Pylolus preserving pancreatoduodenectomy is now being accepted for biliary malignancies, which brings excellent quality of life.

Biliary Tract Neoplasms↗
PubMed1990

The three-dimensional microstructure of intramural lymphatics in the canine large intestine.

The three-dimensional microstructure of the intramural lymphatics of canine large intestine was clarified micrographically. After direct injection of India ink into the colon wall, we prepared 2 less than 3cm full-thickness transparent specimens of the opened colon wall and transparent sections. Lymph vessels were distinguished from blood vessels by intraarterial injection of cinnabar ink. A stereomicroscope was used for observation, and stereograms were reproduced. Lymph vessel networks were present in the shallow and deep layers of the lamina propria mucosae and the deep layer of the submucosa. The lymph vessel networks in the lamina propria mucosae were present immediately beneath the blood capillary networks. The thickest lymph vessels and the densest network appeared in the submucosa. From the submucosa, some of the lymph vessels existed immediately to merge into the collecting trunks and other lymph vessels which compose a minor pathway existed along lymph vessels in the muscular layer and finally merged into the collecting trunks in the subserosa.

Animals↗
PubMed1990

The effects of lying position on ventricular volume in congenital absence of the pericardium.

In patients with congenital absence of the left pericardium, the heart is supported by the existing right pericardium in the right lateral position, while it is not in the left lateral position. To investigate the change in ventricular size resulting from postural change, seven patients with this malformation were examined. Ventricular volumes were calculated by computed tomography, integrating areas of computed tomographic cross sections measured at 1 cm intervals from the cardiac apex to the aortic arch. In the right lateral position, right ventricular (RV) and left ventricular (LV) volumes were no different from those of five control subjects. With a change in the lying position to the left, the increase in the ventricular volume was significantly greater than that in the control subjects (35 +/- 11 versus 3 +/- 3 ml in the right ventricle and 15 +/- 13 versus 3 +/- 8 ml in the left ventricle). The increases in RV and LV end-diastolic pressure, however, were almost the same as those in the 11 control subjects. It is concluded that the cardiac ventricle, especially the right ventricle, dilates significantly with a small increase in preload in patients with congenital absence of the pericardium. It may be a clue for clarifying the ventricular distensibility being freed from physiologic restraint of the pericardium for a long period.

Adult↗
PubMed1990

Effects of acute portal hypertension by portal venous stenosis on systemic hemodynamics in dogs.

Effects of acute portal hypertension on systemic hemodynamics after hepatectomy were evaluated by portal venous stenosis (PVS) model in dogs. In protocol 1, portal hypertension of about twice portal venous pressure (PVP) decreased cardiac output (CO) and left atrial pressure (LAP) by 24.5% (p less than 0.01) and 1.0 mm Hg (p less than 0.01), respectively. In protocol 2, stepwise PVS demonstrated that CO change (%) and LAP change (mm Hg) were inversely proportional to PVP change (r = -0.937 and -0.883, respectively). The ratio of CO change to LAP change with stepwise PVS was comparable to that obtained by repeated hemorrhage in protocol 3. The present study shows that low CO with portal hypertension is caused by a reduction of venous return to the heart.

Acute Disease↗
PubMed1990

Improvement in mitral flow dynamics during exercise after percutaneous transvenous mitral commissurotomy. Noninvasive evaluation using continuous wave Doppler technique.

Evaluation of mitral flow dynamics during exercise is critically important in patients who receive percutaneous transvenous mitral commissurotomy (PTMC) because limited mitral flow during exercise provokes hemodynamic deterioration and involves cardiogenic symptoms in patients with mitral stenosis. To examine mitral flow dynamics during exercise, we applied continuous wave Doppler technique in 20 patients with mitral stenosis. Exercise Doppler study was performed 2 days before and 5 days after PTMC. PTMC increased mitral valve area from 1.0 +/- 0.3 (mean +/- SD) to 1.9 +/- 0.5 cm2 and decreased mean transmitral pressure gradient from 8 +/- 2 to 4 +/- 1 mm Hg at rest. Moreover, PTMC decreased mean transmitral pressure gradient from 21 +/- 6 to 11 +/- 4 mm Hg at submaximal exercise. The extent of an increase in mitral valve area by PTMC correlated with a decrease in the mean transmitral pressure gradient at the submaximal exercise (r = -0.76, p less than 0.01) and that at rest (r = -0.52, p less than 0.05). Heart rate after PTMC during exercise was significantly lower than that before PTMC, indicating that the compensatory mechanism (tachycardia) to increase cardiac output during exercise is less necessary after PTMC. Thus, we conclude that the mitral flow dynamics during exercise is improved, as well as the resting mitral flow dynamics 5 days after PTMC, and that exercise Doppler study enabled us to make a noninvasive evaluation of the mitral flow dynamics in patients who receive PTMC.

Adult↗
PubMed1990

[Venous return and collapse of the right heart in cardiac tamponade].

To elucidate the characteristics of venous inflow into the heart in cardiac tamponade, transmitral (TMF), transtricuspid (TTF) and superior vena cava (SVC) flows were examined using pulsed Doppler echocardiography in nine mongrel open-chest dogs. Cardiac tamponade was produced by the slow infusion of warmed normal saline into the pericardial sac. With increment of pericardial infusion, right atrial collapse (RAC) developed followed by right ventricular collapse (RVC). The systemic blood pressure became depressed and the left ventricular end-diastolic diameter decreased, even in the RAC state, indicating that RVC is not of the primary significance for cardiac tamponade. Characteristically, peak velocities of TMF and TTF in early diastole decreased concomitantly with RAC and RVC. Neither early diastolic filling time nor its acceleration time was altered during tamponade. These changes in blood flow were accompanied by decrements of transmural filling pressure and abnormal motion of the right ventricle. In SVC flow, the diastolic wave characteristically disappeared. This change seemed to be a reflection of the decrease in peak velocity of early diastolic filling flow into the right ventricle. That is, impairment of cardiac relaxation during cardiac tamponade is represented as decreased filling flow velocity in early diastole.

Animals↗
PubMed1990

[Changes in hepatic ultrastructure and function following portal vein resection with a use of an internal shunt bypass].

Experimental studies on ultrastructural and functional changes of mitochondria were carried out using adult dog livers after portal vein resection with an internal shunt bypass. As a comparative study portal vein resection with an external shunt bypass was also carried out. A 10 cm long anti-thrombotic UK catheter was inserted into the portal vein as an internal shunt bypass (internal shunt group). Similarly, a catheter was inserted between the portal vein and inferior caval vein as an external shunt bypass (external shunt group). The time of portal vein shunt bypass was 2 hrs for both groups. During operations, the blood flow of the hepatic artery was blocked. After the bypass was installed, the hepatic artery and the portal vein were declamped. As a control experiment the hepatic artery was clamped without making a shunt bypass (non-shunt group). Left lateral lobe was resected from the liver prior to the shunt implant and then the right lateral lobe was removed 2 hrs after the declamping of the hepatic artery. Biochemical analysis on mitochondria isolated from the livers of the internal and the external shunt groups was carried out. Changes of mitochondrial ultrastructure were also studied using electron microscope. Changes in serum m-GOT and OCT activities were also examined. Essentially no changes were detected in phosphorylating capacities and ultrastructure of mitochondria of the livers obtained from either the external shunt group or the internal shunt group. However m-GOT and OCT activities in the serum were definitely elevated in the external shunt group of animals compared to those in the internal shunt group of animals. This suggests that the permeability of hepatic mitochondrial membranes in the external group of animals was changed probably due to hypoxia. From these results we recommended the application of the internal shunt bypass for hepato-biliary surgery combined with the resection of the portal vein.

Adenosine Triphosphatases↗
PubMed1990

Resection of intrahepatic bile duct carcinoma with hilar bile duct and portal vein invasion--a case report.

A case of resected intrahepatic bile duct cancer with hilar bile duct and portal vein invasion is presented. Percutaneous transhepatic biliary drainage was performed to alleviate jaundice and evaluate the biliary system. Intraductal tumor extension was determined, and an accurate histological diagnosis was made in biopsy material obtained under percutaneous transhepatic cholangioscopy. Preoperative surgical planning was carried out on the basis of an evaluation of the findings of ultrasonography, computed tomography, arteriography, portography and percutaneous transhepatic cholangioscopy. Curative surgery, which included right hepatic lobectomy with total caudate lobectomy and combined resection and reconstruction of the portal vein, was performed. Bilioenteric continuity was re-established by a Roux-en-Y jejunal loop. The histological diagnosis was moderately differentiated tubular adenocarcinoma originated in the right posterior branch of the intrahepatic bile duct. Postoperative recovery was very good, and the patient has now been enjoying a good active social life for the past three years with no signs of tumor recurrence. This case report discusses the accurate diagnosis and rational surgical treatment for intrahepatic bile duct carcinoma with hilar invasion.

Adenoma, Bile Duct↗
PubMed1990

[A clinicopathological study of mucus producing bile duct carcinoma].

Bile duct carcinoma, which produces clinically recognizable mucus, was defined as "mucus producing bile duct carcinoma", and clinicopathological study was carried out in 7 cases of bile duct carcinoma suitable for the definition. All the tumors arose from the intrahepatic bile duct. There were no tumors arising from the extrahepatic bile duct. Superficially spreading mucosal infiltration of carcinoma was recognized in 6 cases out of 7, and accordingly distinct cholangiography after draining mucus through percutaneous transhepatic cholangio-drainage (PTCD) and percutaneous transhepatic cholangioscopy (PTCS) were indispensable for accurate diagnosis of the extent of carcinoma. The prognosis of patients with mucus producing bile duct carcinoma were almost satisfactory if rational operation had been performed according to accurate diagnosis. On the other hand, since mucus producing bile duct carcinoma frequently has a cystic lesion, the relation to biliary cystadenocarcinoma may become a subject of question. We advocate that biliary cystadenocarcinoma should be included in mucus producing bile duct carcinoma since biliary cystadenocarcinoma originally arises from the intrahepatic bile duct and very rarely from the extrahepatic bile duct. But now the concept of biliary cystadenocarcinoma is equivocal and further investigations will be requested.

Adult↗