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Biomedical subjects

A Taira

Publications and source records attributed to A Taira.

At least 235 records · Page 13Linked to original sources
PubMed1986

[Orthotopic allotransplantation of the canine liver; a simplified technic with hypothermia].

A simplified technique of the liver transplantation under hypothermia has been studied in dog. An immersion hypothermia was used in both the donor and the recipient. The temperature of the graft at excision was lowered to 20 degrees C with supplemental use of topical cooling. The temperature of the recipient was lowered at 27 degrees C when the transplantation was attempted. Chlorpromazine and dopamine were employed beneficially in hypothermia. No perfusion or irrigation of the graft was performed. The use of heparin was avoided. Anastomoses were carried out in turn of the proximal vena cava, portal vein, distal vena cava and the hepatic artery with a stem shaped aorta. Reperfusion was established after the completion of anastomosis between the proximal vena cava and portal vein. The anhepatic phase of the recipient was uneventfully lasted without heparinization. All dogs, 5 out of 11 without early surgical troubles survived more than 5 days. Immunosuppressive therapy was not employed except one which died of pneumonia on the 19th postoperative day. Histologically, these dogs were free from ischemic injury and/or thrombotic lesion throughout transplantation procedure.

Animals↗
PubMed1986

[Acute and chronic experimental tricuspid valvular stenosis in dogs].

Acute and chronic experimental tricuspid valve stenosis was produced in 20 dogs. Clinical and hemodynamic alterations that resulted from severe anatomic tricuspid valve narrowing were surprisingly mild. In the acute stenosis studies, the normal tricuspid valve area of 8.2 +/- 0.3 sq cm was narrowed to less than 1.0 +/- 0.1 sq cm with a resulting right auricle-right ventricle diastolic gradient of 3.7 +/- 0.7 mm Hg. In chronic studies, a decrease in tricuspid valve area from 7.6 sq cm to 1.6 +/- 0.3 sq cm produced a diastolic gradient of 1.8 +/- 0.2 mm Hg. After 60 days, overt signs of right-sided failure (pleural effusions and ascites) were absent, and histological evidence of passive congestion (liver and spleen) was not recognized. The splanchnic vascular beds appear to act as excellent buffers against increases in right-sided cardiac pressure. We conclude that isolated narrowing of the tricuspid valve must be very severe to cause notable clinical and hemodynamic changes.

Animals↗
PubMed1986

[Continuous wave Doppler echocardiographic assessment of prosthetic aortic valves].

To assess the prosthetic aortic valve functions according to types and sizes of valves, the peak flow velocity was recorded by means of continuous wave Doppler echocardiography in 40 patients (age 45 +/- 15 years) with prosthetic aortic valves and in 25 normal subjects. Twenty-one patients had Björk-Shiley valves (1-18 months after replacement); 12 had St. Jude Medical valves (6-48 months after replacement); and seven had Carpentier-Edwards porcine xenografts (48-84 months after replacement). The peak blood flow velocity across the prosthetic valve was recorded at the left ventricular apex, the suprasternal notch, and the right parasternal border in the second intercostal space. The pressure gradient was derived from the peak flow velocity by means of the simplified Bernoulli equation (P = 4V2). The peak and mean flow velocities and the peak and mean pressure gradients were measured to evaluate the opening function of the prosthetic valves. The results were as follows; The peak flow velocities were recorded in 33 patients (83%) with aortic valve replacements. All four measurements were significantly greater in patients with prosthetic aortic valves than in normal subjects, but there was no significant difference according to the valve type. The opening function was less in patients with smaller valves than in those with larger ones. There was a clear correlation between opening function and valve size. We concluded that continuous wave Doppler echocardiography is a useful noninvasive method for evaluating the opening function of a prosthetic aortic valve.

Adult↗
PubMed1985

Function of the transplanted canine heart after prolonged preservation by simple immersion.

The purpose of this study was to investigate the maximum limits of a simple topical cooling method with preservation of graft viability following orthotopic transplantation. Coronary vascular washout was performed with cold potassium-verapamil cardioplegia. The heart was then removed, suspended in the same solution, and stored at 4 degrees C. The experimental material was divided into three groups according to the preservation time: 24 h in group I (six animals), 36 h in group II (five animals), and 48 h in group III (three animals). All six animals in group I and four of five animals in group II maintained a stable recipient circulation after transplantation. No animals in group III could be taken off cardiopulmonary bypass. Contraction band injury after transplantation was more frequently observed in the group II grafts than in those of group I. In conclusion, the combination of coronary vascular washout with cold potassium-verapamil cardioplegia and storage at 4 degrees C in the same solution may preserve the canine heart for 24-36 h, as demonstrated by cardiac function immediately after orthotopic transplantation.

Animals↗
PubMed1985

Orthotopic transplantation of the canine heart after prolonged preservation by simple immersion.

The viability of the heart was assessed following orthotopic transplantation. Following coronary vascular washout with cold potassium-verapamil cardioplegia, the heart was removed, immersed in the same solution, and stored at 4 degrees C for 24 hours in Group I (6 animals), 36 hours in Group II (5 animals), and 48 hours in Group III (3 animals). All six animals in Group I and four of five animals in Group II maintained a stable recipient circulation for the acute phase of 2 hours after transplantation, without cardiopulmonary bypass. For the dogs in Group III, cardiopulmonary bypass was vital. Contraction band injury after transplantation was more frequently observed in the Group II grafts than those of Group I. We conclude that the combination of coronary vascular washout with cold potassium-verapamil cardioplegia and storage at 4 degrees C in the same solution may preserve the canine heart for up to 24 to 36 hours, as demonstrated by post-orthotopic transplantation function.

Animals↗
PubMed1985

Cyanosis in atrial septal defect due to persistent eustachian valve.

Two cyanotic patients had venoarterial shunting from the inferior vena cava to the left atrium in an uncomplicated atrial septal defect with normal right ventricular pressures. Cyanosis was due to a large, anomalous inferior vena caval valve, the eustachian valve. The mechanism of cyanosis and technical problems for surgical repair are discussed.

Adolescent↗
PubMed1985

[Continuous wave Doppler assessment of prosthetic valves in the mitral position: comparison of the St. Jude medical mechanical valve and the porcine xenograft valve].

To assess the opening function of prosthetic valves in the mitral position with special reference to the type and size of the valve and the years since replacement, we recorded maximum flow velocity through the mitral orifice using continuous wave Doppler echocardiography for 50 patients with mitral valve replacement and 15 normal subjects. There were 33 patients with St. Jude Medical valves and 17 with porcine xenograft valves. An ultrasonic transducer was placed over the left ventricular apex and the direction of the ultrasonic beam was positioned to be parallel with mitral flow using the Doppler audio signals. A pressure gradient was calculated from continuous wave Doppler flow velocity with a simplified Bernoulli's equation proposed by Hatle et al. The peak and mean maximum flow velocity, mean pressure gradient across the valve and the pressure half time were measured to evaluate the opening function of the prosthetic valve. The results were as follows: All four measurements were significantly larger in patients with valve replacements than in normal subjects, and were significantly increased in patients with porcine xenograft valves compared to those with St. Jude Medical valves. The opening function was well maintained in patients having larger valves than in those having smaller ones in the group of St. Jude Medical valve replacement. In patients who had porcine xenograft valve for four years or more, the opening function was decreased the more years they had been implanted. We conclude that continuous wave Doppler echocardiography is a useful noninvasive method for the quantitative assessment of the diastolic opening function of the prosthetic mitral valve.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[A comparative study of experimental models for cardiac preservation through orthotopic transplantation].

Various kinds of models for canine heart preservation were evaluated through orthotopic transplantation. Following warm ischemic (WIT) and preservation times (PT), donor hearts were orthotopically transplanted to recipients and observed for 2 hours. The study was divided into four groups. A heart-lung preparation (Group A) was preserved by coronary perfusion with diluted blood for an hour following 15-minute WIT in A-1 (n = 33), and 2 hours following 30-minute WIT in A-2 (n = 19). Following 30-minute WIT, the heart (Group B) was preserved for an hour by coronary perfusion with diluted blood in B-1 (n = 20), a modified Krebs solution in B-2 (n = 14), and a EL-solution in B-2 (n = 14). Following 30-minute WIT, the heart (Group C) was preserved for 2 hours by a Langendorff's model with coronary perfusion using perfluorochemical in C-1 (n = 5) and Hydroxyethyl starch in C-2 (n = 1). In Group D, electromechanical arrest of the heart and coronary vascular washout were performed in D-1 (n = 8) with K+ cardioplegia, D-2 (n = 8) with K+-verapamil cardioplegia, and D-3 (n = 5) with Collins M-verapamil cardioplegia. The heart was then removed and suspended in the same solution. The graft was preserved at 4 degrees C for 6 hours in D-1 and D-2, and 24 hours in D-3. Fourty-eight % in A-1 and 26% in A-2 were successfully transplanted.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Cardioplegia].

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Adenosine Triphosphate↗