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Biomedical subjects

R Omoto

Publications and source records attributed to R Omoto.

At least 109 records · Page 6Linked to original sources
PubMed1991

Multicentre clinical trial of antirejection pulse therapy with deoxyspergualin in kidney transplant patients.

The present randomized comparative clinical trial was carried out to confirm the efficacy of a newly developed immunosuppressive drug, 15-deoxyspergualin (DSG), and also to find its optimal dose for antirejection pulse therapy. The study included 66 patients with rejection which had occurred within 6 months after renal transplantation. They were treated with DSG at 3, 5 or 7 mg/kg/day for 5 days. The overall percentage of efficacy was 73% and the percentage of efficacy was the highest in the 3-mg/kg group (82%). The incidence of adverse reaction tended to be dose-dependent. From these results, the optimal dose of DSG was judged to be 3-5 mg/kg/day for antirejection pulse therapy, and at doses in this range the percent efficacy could be expected to be 80% or more.

Graft Rejection↗
PubMed1991

Emergency surgical intervention of acute aortic dissection with the rapid diagnosis by transesophageal echocardiography.

Forty-five serial patients with acute aortic dissection were examined by transesophageal color Doppler echocardiography (TEE), and the diagnosis was made without aortography. No complications related to TEE occurred. Sufficient information for surgery was immediately obtained at the bedside by the TEE examination. Forty-four of 45 patients (98%) were diagnosed accurately, and 20 emergency operations for patients with type A aortic dissection and six emergency operations for patients with type B aortic dissection were performed. In only one patient, a small intimal flap in the ascending aorta was not detected by TEE. The operative mortality rate was 20% and 50% for types A and B aortic dissections, respectively. As a result of the progress of biplanar TEE technology, an easier and more accurate diagnosis of patients with acute aortic dissection can be achieved. The immediate and accurate diagnosis of acute aortic dissection can be achieved by TEE at the bedside, and treatment strategy can be more precisely determined.

Adult↗
PubMed1990

[On-line angle correction of color flow mapping images using a personal computer].

To quantitatively assess flow area or kinetic energy in color flow mapping (CFM), angle correction, which has been totally ignored using current systems, is now considered indispensable. To reconstruct flow images using angle-corrected velocity mapping, we incorporated a personal computer (NEC PC-LT) in the cine-memory of a CFM system (Aloka SSD-870). To demonstrate the effect of angle correction on CFM, the maximum left ventricular diastolic flow images were obtained in seven normal adults using the apical long-axis views where the angle of incidence was less than 10 degrees, and the parasternal long-axis view, where the angle of incidence was between 40 and 60 degrees. A 3.5 MHz probe with a 4 KHz pulse repetition frequency at a frame rate of 10/sec was used. Flow area and kinetic energy of the original and angle correction images in the aliased parts and the total flow areas were calculated and expressed as percent values of the control (color correction image of total flow area in the apical view). The total flow area of the original image in the apical view was 96.4% and 87.2% in the parasternal view, or 98.6% by effective angle correction, and the kinetic energy of the original image in the apical view was 94.0% and 58.8% in the parasternal view, or 93.3% by angle correction. In conclusion, although flow area and kinetic energy of the original image in the parasternal view were significantly less than those of the original and the angle correction images in the apical view (p less than 0.05), they could effectively be evaluated by angle correction. Thus, this system can contribute to quantitative assessment of CFM.

Adult↗
PubMed1990

[Evaluation of patency of internal mammary artery grafts: a comparison of two-dimensional Doppler echocardiography with coronary angiography].

To examine the clinical feasibility of color flow mapping Doppler echocardiography (CFM) in diagnosing the patency of internal mammary artery (IMA) grafts, 41 patients who had had coronary bypass surgery were examined by both CFM and coronary angiography (CAG) within one week of the CFM examination. Coronary bypass surgery was performed one to eight months prior to this study, and the average number of bypass grafts was 2.7 +/- 0.7. The patency of the IMA grafts was confirmed in all except one patient by CAG; whereas, the flow in the IMA grafts was clearly visualized in all 22 patients by CFM from the left parasternal echo window. Peak velocities of the IMA graft flow in the 22 patients were 31.7 +/- 12.0 (19-49) cm/sec in diastole and 14.9 +/- 8.5 (5-36) cm/sec in systole. No false positive diagnosis was made in the CFM examination. The sensitivity, specificity, negative predictive value, and positive predictive value of CFM in the diagnosis of IMA graft patency were 55%, 100%, 5.3% and 100% respectively. In conclusion, although the sensitivity of color Doppler still remains relatively low, its specificity in the diagnosis of IMA graft patency is 100%. Thus, color Doppler is expected to be valuable for long-term follow-up of IMA graft patencies.

Adult↗
PubMed1990

[Advantages of transesophageal color Doppler echocardiography in the diagnosis and surgical treatment of cardiac masses].

To determine the clinical advantages of transesophageal color Doppler echocardiography (TEE) for imaging cardiac tumors and left atrial thrombi, 24 cases with intra- or extracardiac masses were examined by transthoracic color Doppler echocardiography (TTE) and TEE before and after cardiac surgery. Five with left atrial myxomas, two with lung tumors, five with mediastinal tumors and 12 with mitral stenosis coexisting left atrial thrombi were included in this study. The echocardiographic findings of the cardiac masses were compared with the surgical findings in all cases. In all of the five cases with left atrial myxomas, the tumors were detected. However, the sites of attachment and a stalk in three cases were not observed by TTE. TEE clearly imaged the left atrial myxomas, and evaluated the size and shape of the tumors, the sites of their attachment and a stalk arising from the interatrial septum, and mobility in four cases, except for one in which there was a broad attachment to the endocardium. Mitral regurgitation was detected in only two cases using the color Doppler mode of TTE, but in all cases using TEE. Both techniques failed to recognize tissue characterization. Among seven cases with secondary cardiac tumors or mediastinal tumors, extracardiac masses were detected in five; however, an intracardiac tumor attached to the interatrial septum and an extracardiac tumor extending to the superior vena cava and an upper part of the right atrium could not be imaged using TTE. TEE detected all tumors at all sites in the heart and vessels, and estimates of their extents were in accord with the operative findings in 17 of 18 sites. One exceptional case had a tumor which extended to the right ventricle. Neither technique could detect infiltration of the heart which was present in five of the seven cases. Multiple left atrial thrombi were observed in eight of 12 cases, resulting in 21 thrombi and they were diagnosed by TEE in six of 12 cases. Thrombi, when attached to the left atrial posterior or inferior walls, were easily detected in four of five cases, but were not identified in four of six and in eight of nine cases at the lateral wall or in the left atrial appendage by TTE. However, TEE detected all thrombi in every site in the left atrium and left atrial appendage in 11 of 12 cases. TEE was thus superior to TTE in detecting cardiac masses, recognizing abnormal flow and estimating anatomical relationship between tumors or thrombi and cardiac structures.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Early diagnosis and surgical intervention of acute aortic dissection by transesophageal color flow mapping.

To determine whether transesophageal color Doppler echocardiography (TEE) is useful for the early diagnosis and surgical intervention in acute aortic dissection, 57 serial patients with acute aortic dissection were examined. These patients were evaluated by TEE with either the single-plane probe (39 patients) or the biplanar probe (18 patients) just after admission. The intimal flap was detected in all patients, and there were 18 patients with type A dissection and 39 patients with type B dissection. The entry was visualized in 83% of type A dissection cases and in 90% of type B dissection cases. In two of 18 patients examined with the biplanar probe technique, the entry was detected in the longitudinal view only. Emergency operations were performed in 18 patients with type A dissection and in 10 patients with ruptured type B dissection. Twenty-nine of 39 patients with type B dissection were treated conservatively. The operative mortality rate of patients with type A dissection was 22%, and that of patients with ruptured type B dissection was 60%. The major advantage of TEE is its ease of application at the bedside or in the operating room, which allows immediate and accurate diagnosis of acute aortic dissection for emergency surgical intervention. Biplanar TEE provides additional acoustic windows, ease of spatial orientation, and more accurate visualization of entry. TEE is a useful and powerful diagnostic tool for acute aortic dissection, and by using this method, one may achieve a more rapid and aggressive surgical approach for patients with acute aortic dissection.

Acute Disease↗
PubMed1990

The value of Doppler echocardiography in the treatment of tricuspid regurgitation in patients with mitral valve replacement. Perioperative and two-year postoperative findings.

The treatment for tricuspid regurgitation in patients who have mitral valve replacement remains controversial partly because of the lack of a convenient method for measuring reflux. The purpose of this study was to assess Doppler measurement of tricuspid regurgitation in selecting patients for surgical or nonsurgical management and in evaluating the results. Thirty-three patients who had mitral valve surgery had three ultrasound examinations: before operation, before discharge from hospital, and 2 years after operation. Seventeen patients were assigned to tricuspid annuloplasty and 16 to no procedure. Assignment was based on visual grading of regurgitant velocity maps and intraoperative grading by direct palpation. Before operation patients in the annuloplasty group had larger mean jet velocity areas, right atrial size, and diastolic transvalvular velocities than had the nonsurgical group. However, the overlap of data precluded the definition of thresholds for separating the patients into either of two regimens. Early after operation the patients with annuloplasties showed decreased regurgitant indexes similar to the preoperative levels of patients who had no procedure; the latter preoperative levels had not changed. Late after operation both groups showed stabilization or trends toward less regurgitation, and continued decreases in tricuspid diastolic flow velocities. Thus Doppler ultrasonography played a complementary role in selecting patients for annuloplasty or nonsurgical management and a major role in the longitudinal evaluation of treatment.

Echocardiography, Doppler↗
PubMed1990

A novel rescue drug, 15-deoxyspergualin. First clinical trials for recurrent graft rejection in renal recipients.

The present multicentral clinical study performed in 6 institutes demonstrated that the novel immunosuppressive agent, 15-deoxyspergualin (DSG), is very effective on rejection. In 34 cases of rejection, 30 were treated with DSG at 40 mg/m2 (1 case), 80 mg/m2 (7 cases), 120 mg/m2 (9 cases), 180 mg/m2 (9 cases), and 220 mg/m2 (8 cases). The overall remission rate was 79% in 34 cases of rejection including accelerated, acute, and chronic rejection in different periods after transplantation. Analyzing the remission rates of early phase acute rejection occurring within 3 months after transplantation according to treatment pattern, the remission rate was 100% in 3 cases treated with DSG alone (using DSG 1 week or longer after other agents), 88% in 8 cases treated by rescue use of DSG (using DSG within 1 week after other agents), and 86% in 7 cases treated by combined use of DSG with other agents. Adverse reactions included reductions in WBC and platelets, anemia, perioral numbness, gastrointestinal troubles, and others. However all these symptoms were so mild that DSG treatment was not discontinued. Further studies are necessary on the effect of DSG, especially in acute rejection under conditions that reduce the many influences of other agents as much as possible.

Adult↗
PubMed1989

Doppler echography for hemodynamic studies of the azygos vein.

Using a convex array transducer, the advantages and shortcomings of transesophageal real-time two-dimensional Doppler echography (TE2DD) were assessed in a study of the vessels around the esophagus and the stomach in 67 adult patients with (n = 56) or without (n = 11) liver cirrhosis. In most cases, all but the upper- and lowermost margins of the azygos vein could be visualized. The more caudally the portion located, the smaller its diameter and flow velocity became. The average number of intercostal veins visualized by TE2DD was 4 per person. The observable esophagogastric varices seemed to be limited to deeply located ones around the esophagogastric junction. In five patients who had undergone distal splenorenal shunt, splenic venous flow, or shunt flow could be seen from the stomach over a length of about 5 cm. The azygos venous flow in cirrhotic patients was significantly greater than that of patients without cirrhosis. TE2DD appears to be very useful for evaluating flow in the cephalad collateral veins and other vessels around the esophagus and the stomach.

Adult↗
PubMed1989

The effects of a prostacyclin analog OP-41483 on pulmonary oxygen toxicity in an isolated heart-lung autoperfusion model.

Using an isolated canine heart-lung autoperfusion model, the effect of prostacyclin analog (OP-41483) on pulmonary oxygen toxicity was investigated. Twenty-four mongrel dogs were divided into four groups. Groups 1 and 2 inspired oxygen at concentrations (FiO2) of 0.95 and 0.6, respectively, while groups 3 and 4 received OP-41483 (0.1 micrograms/kg/min) in addition to FiO2 of 0.95 and 0.6. Autoperfusion was performed for five hours, and during the experiments the systolic blood pressure was maintained at 100 mmHg and the cardiac output at 40 ml/kg/min. After five hours of perfusion, PaO2 decreased significantly (P less than 0.01) from 410 +/- 49 mmHg to 237 +/- 38 mmHg in group 1, and also decreased significantly (P less than 0.01) from 368 +/- 44 mmHg to 243 +/- 26 mmHg in group 2. However, no significant changes in PaO2 were observed in groups 3 and 4. The pathological examinations clearly revealed perivascular edema and vascular dilation in groups 1 and 2, whereas no abnormal pathological findings were seen in groups 3 and 4. The above results indicate that OP-41483, when administered at the low dose of 0.1 micrograms/kg/min, induces no circulatory changes and exerts an effective action with respect to the prevention of pulmonary edema.

Animals↗