Biomedical subjects

S Imawaki

Publications and source records attributed to S Imawaki.

22 records · Page 2Linked to original sources

PubMed1987

Extra-anatomical bypass formation and exclusion of thoracic aortic aneurysms by "paired clamp method": the development of hind leg paralysis, the thrombus formation and the pressure ratio between the excluded cavity and the aorta.

The extra-anatomical bypass formation and the exclusion of thoracic aortic aneurysms by the "paired clamp method" applied to the thoracic aorta of mongrel dogs, and the development of hind leg paralysis was studied experimentally in relation to the ratio between the mean excluded cavity pressure and the mean aortic pressure ratio (EA-ratio). The relationship between thrombus formation in the excluded cavity and the EA-ratio was also studied. Animals were divided into 4 groups: Group 1 underwent the cross-clamping of the descending thoracic aorta for 8 min; Group 2 underwent exclusion of the entire thoracic aorta under permanent bypass; Group 3 underwent ligation of 2/3 of the proximal intercostal arteries which branched from the excluded thoracic aorta; and Group 4 underwent division of the excluded thoracic aorta into 3 parts by ligation. No animals in group 1 developed paralysis. When EA-ratios were higher than 0.48, animals in groups 2 and 3 were not paralyzed, whereas all but 1 animals with EA-ratios lower than or equal to 0.48 were paralyzed. There was statistically significant difference between the EA-ratio of the non-paralyzed animals and that of the paralyzed animals in groups 2 and 3. Four out of 5 animals in group 4 were paralyzed. However, there was no statistically significant difference between the EA-ratio in these 4 paralyzed animals and that in the non-paralyzed animals in groups 2 and 3. When the EA-ratio was lower than or equal to 0.59, all but 1 excluded cavities of groups 2 and 3 animals were fully thrombosed 7 or 8 days after the operation. None of these animals showed the aggravation of the paralysis during the observation period and, conversely, the paralysis of almost all animals was ameliorated. These results suggested that the EA-ratio is useful in predicting the development of paralysis and thrombus formation in the excluded cavity after the operation of thoracic aortic aneurysms by the "paired clamp method".

Animals↗

PubMed1987

[Adenocarcinoma of an extraperitoneal rectum in a 17-year-old female].

A 17-year-old female with an adenocarcinoma of the extraperitoneal rectum, which was diagnosed correctly by preoperative intrarectal ultrasonography as being in Dukes' A stage, was operated on, this surgery performed adhering to function preserving procedures. Histologically, the tumor uncovered was found to be a well differentiated adenocarcinoma and, as had been expected, in Dukes' A stage. An absolute curative operation was achieved. The operative procedure for juvenile rectal cancer must be planned to achieve both tumor removal and bodily function preservation to assure the best possible quality of postoperative life. We recommend intrarectal ultrasonography at the preoperative stage, the results to be used in deciding on the operative procedure.

Adenocarcinoma↗

PubMedDate not supplied

Repair of both papillary and free wall rupture following acute myocardial infarction.

A 60-year-old patient with rupture of the papillary muscle combined with free wall rupture secondary to myocardial infarction is described. Transesophageal echocardiography was useful in making the diagnosis. Surgery was performed 2 days after the onset of acute myocardial infarction, and patch reinforcement of the ruptured wall and mitral valve replacement were effective. Only one case of this type of double rupture has been reported, and this is the first case to have been repaired surgically. It may be unusual for double rupture to occur because the first rupture decreases wall stress to less than the normal level.

Coronary Angiography↗

PubMedDate not supplied

A pulsatile cardiopulmonary bypass system that prevents negative pressure at the membrane oxygenator.

Negative pressure is a problem in pulsatile cardiopulmonary bypass (CPB). To avoid this, the authors designed a pulsatile CPB system containing a Sarns centrifugal pump (CP) and a Univox membrane oxygenator, in which the inertial flow is not obstructed by the CP. In both an in vitro study and a clinical study, negative pressure was not observed in the arterial line of the CPB circuit when this system was used. When a roller pump (RP) was used, however, instead of a CP, negative pressure did occur. In a clinical study using this system, mean pulse pressure was 36 mmHg and hemolysis, expressed as the rate of rise in plasma free hemoglobin from 10 to 70 min of CPB, was 26.2 mg/dl/hr, which did not exceed that seen with a pulsatile CPB using an RP instead of a CP. The hemolysis seen in the study caused no clinical problems. Thus, pulsatile CPB using a CP and Univox membrane oxygenator should be considered for clinical use to prevent the occurrence of negative pressure.

Cardiopulmonary Bypass↗