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Biomedical subjects

A Harada

Publications and source records attributed to A Harada.

At least 289 records · Page 16Linked to original sources
PubMed1988

Systemic hemodynamics in non-cirrhotic portal hypertension--a clinical study of 19 patients.

The features of systemic hemodynamics were analyzed in 19 non-cirrhotic patients with prominent esophageal varices. The patients were divided into two groups; Group I comprised 8 patients with an occluded extra-hepatic portal vein and Group II comprised 11 patients with a patent extra-hepatic portal vein whose histopathological diagnosis was idiopathic portal hypertension or hepatic fibrosis. An increase in the cardiac index and a decrease in the total peripheral resistance were significant in both groups when compared with 12 control patients (p less than 0.01). There was a significant correlation between the cardiac index and plasma volume in the 14 non-cirrhotic patients with portal hypertension (r = 0.537, p less than 0.05), but no significant relationships were identified between the cardiac index and liver functional values. These results reveal that the systemic hemodynamics in non-cirrhotic portal hypertension are significantly hyperdynamic, as in cirrhotic portal hypertension. They also suggest that the expanded plasma volume secondary to the enlargement of the portal bed might be closely related to the mechanism of hyperdynamic systemic circulation in non-cirrhotic portal hypertension.

Adolescent↗
PubMed1988

[Arterial infusion of anticancer agent and lipiodol using a totally implanted drug delivery system].

We attempted arterial infusion of anticancer agent using a totally implanted drug delivery system in 52 patients who had inoperable liver cancer or the scheduled adjuvant chemotherapy after hepatic resection. The response rate of the cases using lipiodol was 38%, while that of the cases using only ADM and MMC was 0%. We studied changes in serum concentration of ADM and MMC. The results indicated that using 60% Urographin to make ADM, MMC-lipiodol emulsion was effective for targetting and control release.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Potential distribution mapping. New method for precise localization of intramural septal origin of ventricular tachycardia.

Ventricular tachycardia that requires surgical management frequently arises from intramural sites in the ventricular septum. However, epicardial and endocardial activation-time maps are incapable of identifying these intramural sites. To overcome this limitation, we have developed potential-distribution mapping with newly designed epicardial and endocardial electrodes for the right and left ventricles. During normothermic cardiopulmonary bypass in eight dogs, these endocardial electrodes were introduced into the right ventricular and left ventricular cavities through right and left atriotomies. The heart was paced with a plunge-needle electrode positioned to mimic ventricular tachycardias originating intramurally in the ventricular septum. Potential-distribution maps were then constructed from 61 epicardial, 30 right ventricular endocardial, and 31 left ventricular endocardial unipolar electrograms to determine if surface potential-distribution maps could localize the intramural septal pacing site. The primary potential minima (less than -3 mV) in both right ventricular and left ventricular endocardium occurred in the electrodes closest to the intramural septal pacing site. At the instant of occurrence of the primary potential minimum, the amplitude of the adjacent potential maximum was more positive when the pacing site was more distant from the endocardial surface. Therefore, the amplitude of the coexisting potential maximum was an important indicator of depth of the pacing site. The time difference between the occurrence of right ventricular and left ventricular primary potential minima correlated with depth of the intramural pacing site and was also a valid predictor of the intramural pacing site. The intramural pacing site interpolated from the endocardial sites and the time difference of right ventricular and left ventricular primary potential minima was within 3.2 +/- 1.2 mm of the actual pacing site determined by postmortem examination. Endocardial breakthrough of wavefronts on the right ventricular and left ventricular septal surfaces obtained from corresponding activation-time maps were less accurate in indicating the electrodes closest to the pacing site. Neither epicardial activation-time maps nor potential-distribution maps were capable of identifying the intramural septal pacing site. Thus, unlike conventional endocardial activation-time maps, endocardial potential-distribution maps are capable of more accurate localization of the origin of ventricular tachycardias arising in the intramural ventricular septum.

Animals↗
PubMed1988

A scanning electron microscopy and electron probe X-ray microanalysis (SEM-EPMA) of pink teeth.

Samples of postmortem pink teeth were investigated by scanning electron microscopy and electron probe X-ray microanalysis. Fracture surfaces of the dentin in pink teeth were noticeably rough and revealed many more smaller dentinal tubules than those of the control white teeth. Electron probe X-ray microanalysis showed that the pink teeth contained iron which seemed to be derived from blood hemoglobin. The present study confirms that under the same circumstance red coloration of teeth may occur more easily in the teeth in which the dentin is less compact and contains more dentinal tubules.

Animals↗
PubMed1988

Right atrial isolation: a new surgical treatment for supraventricular tachycardia. I. Surgical technique and electrophysiologic effects.

This study describes the surgical technique and electrophysiologic effects of isolating the right atrium while preserving normal function and continuity of the sinoatrial node with the remainder of the heart. Thirteen adult mongrel dogs underwent normothermic cardiopulmonary bypass. A posterorlateral right atriotomy was performed that encircled the upper right atrium but excluded the atrial pacemaker complex. The incision was extended anteromedially to the tricuspid valve anulus just anterior to the membranous interatrial septum and inferiorly just posterior to the os of the coronary sinus and the tricuspid valve anulus. Postoperatively, electrophysiologic data confirmed (1) that the body of the right atrium was electrically isolated from the remainder of the heart, (2) that the sinoatrial node continued to function normally, and (3) that the sinoatrial node remained in continuity with the left atrium and ventricles. Right atrial tachycardia was simulated by rapid right atrial pacing and was confined to the isolated right atrium. Moreover, the simulated tachycardia did not affect normal sinus rhythm or normal atrioventricular conduction. It is concluded that isolation of the right atrium with preservation of normal sinoatrial node function and continuity is feasible. This technique offers an alternative to the current surgical approaches for management of refractory supraventricular tachycardias that arise in the right atrium.

Animals↗
PubMed1988

Right atrial isolation: a new surgical treatment for supraventricular tachycardia. II. Hemodynamic effects.

Surgical isolation of the body of the right atrium presents a unique hemodynamic situation in which the synchronous right atrial contraction (kick) is lost but the synchronous left atrial contraction is preserved. The hemodynamic effects of this procedure were evaluated by pacing at selected atrial sites postoperatively to simulate (1) sinus rhythm with a synchronous right atrial kick, (2) sinus rhythm without a synchronous right atrial kick, (3) right atrial tachycardia propagated to the entire heart (propagated right atrial tachycardia), and (4) right atrial tachycardia confined to the isolated right atrium with sinus rhythm in the rest of the heart (confined right atrial tachycardia). Hemodynamic data recorded under these four conditions showed that (1) during sinus rhythm, synchrony of right atrial contraction had no significant effect on any of the hemodynamic parameters studied and (2) conversion from propagated right atrial tachycardia to confined right atrial tachycardia resulted in an increase in mean arterial pressure (65 +/- 5 to 78 +/- 3 mm Hg, p less than 0.005) and stroke volume index (9 +/- 1 to 19 +/- 3 ml/beat/m2, p less than 0.005) with a decrease in left atrial pressure (9 +/- 2 to 5 +/- 1 mm Hg, p less than 0.05) and right atrial pressure (6 +/- 1 to 5 +/- 1 mm Hg, p less than 0.05). Moreover, cardiac hemodynamic performance remained within normal limits for up to 14 weeks. Thus the right atrial isolation procedure does not adversely affect cardiac hemodynamics despite the loss of synchronous right atrial contraction during sinus rhythm, and the procedure prevents hemodynamic deterioration during right atrial tachycardia.

Animals↗
PubMed1987

Effects of sodium tetradecyl sulfate endoscopic variceal sclerotherapy on the esophagus. A prospective clinical and histopathologic study.

A prospective clinical, endoscopic, and histopathologic study of the esophagus was carried out in 24 patients with advanced liver disease who underwent esophageal variceal sclerotherapy (EVS) and who eventually came to autopsy. Patients were arbitrarily divided into three groups: acute (group I), intermediate (group II), and chronic (group III) based on the interval between the first EVS and death. EVS with sodium tetradecyl sulphate (STS) initially produced thrombosis with varying degrees of necrosis and inflammation followed by ulceration, recanalization, and eventually fibrosis with obliteration of varices. Recurrent variceal hemorrhage (VH) leading to death was highest in the acute group since all patients died of uncontrollable VH (100%); it ranged between 50-60% in both the intermediate and chronic groups. Despite variceal obliteration, recurrent hemorrhage developed in the chronic group due to gastric varices or other venous channels in the esophagus or stomach. Additionally, we describe findings not previously reported, such as the presence of sclerosant outside the varices after intravariceal injection, thrombosis of gastric varices after esophageal injections, and the development of muscular wall thickening.

Adult↗
PubMed1987

[Clinicohistopathological and immunohistochemical studies on intrapancreatic spread of pancreatic carcinoma].

Clinicohistopathological and immunohistochemical studies on intrapancreatic spread of pancreatic carcinoma were performed on 30 cases with total pancreatectomy accompanied by portal vein resection. In the observation of HE stained tissue sections of 25 cases of carcinoma of head of the pancreas, the intrapancreatic spread from the head to body or tail was observed in 9 out of 25 cases (36%). However, by the immunostaining of CEA, CA19-9 and Dupan 2, small cancer nests surrounded by fibrous tissues could be easily detected and intrapancreatic continuous spread from the head to body or tail was observed in 15 out of 25 cases (60%). The intrapancreatic spread of the carcinoma correlated with portal invasion of carcinoma, hardness of the body and tail, obstruction of main pancreatic duct and irregular pancreaticogram. The intraoperative quick immunostaining on the cryostat sections of the pancreatic tissue, together with the HE staining, is useful to determine the intrapancreatic spread of the carcinoma. The indication of total pancreatectomy for pancreatic carcinoma can be determined by these results.

Antigens, Neoplasm↗
PubMed1987

[Preparation of an antithrombogenic bypass-catheter of the portal vein and its application to extended radical surgery in pancreatic cancer].

The curative resectability of pancreatic cancer has been considered to be extremely low. One of the reasons for this is invasion of the pancreatic cancer cells into the portal vein, and resection of the portal vein in the usual manner would bring create various problems following acute portal vein occlusion. Sudden occlusion of the portal vein has been shown to cause profound and fatal shock in animal experiments. Now, however, with our newly developed procedure of bypassing the portal blood into the systemic circulation or intrahepatic portal vein using an antithrombogenic bypass-catheter, made from heparinized hydrophilic polymer (Toray, Anthron), combined resection of the portal vein can be performed with safety and ease. Using the catheter-bypass method, 55 pancreatectomies accompanied by portal vein resection have been safely performed, mostly in patients with pancreatic cancer. Occlusion time of the portal vein ranged from 20-302 minutes (mean, 94 minutes). No side effects of the catheter were observed. The rate of occurrence of postoperative thrombosis of the portal vein was 1.8% (1/55) and operative mortality was 7.3% (4/55). Resectability rate for pancreatic cancer was 11.2% (5/42) between 1971 and 1980, but this has been remarkably improved to over 60% (53/87) in the period between 1981 and August 1986 by the application of the catheter-bypass method. This method is recommended not only for pancreatic cancer operations but also for hepatobiliary surgery.

Catheterization↗