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Biomedical subjects

T Magara

Publications and source records attributed to T Magara.

At least 37 records · Page 2Linked to original sources
PubMed1994

Optimal perfusion pressure for experimental retrograde cerebral perfusion.

We evaluated cerebral metabolism during retrograde cerebral perfusion (RCP) and circulatory arrest during profound hypothermia, and also investigated the effects of perfusion pressure on RCP. Twenty-four adult mongrel dogs were placed on cardiopulmonary bypass and cooled to a nasopharyngeal temperature of 20 degrees C. At this temperature, hypothermic circulatory arrest (HCA; n = 6), and RCP with a perfusion pressure of 10 mmHg (RCP10; n = 6), 20 mmHg (RCP20; n = 6), and 30 mmHg (RCP30; n = 6) were carried out for 60 minutes. RCP was performed with oxygenated blood via the bilateral maxillary veins, and the retrograde flow rate was regulated to maintain a mean perfusion pressure of 10, 20, or 30 mmHg in the external jugular vein. At 60 minutes of RCP, we measured nasopharyngeal temperature; regional cerebral blood flow (rCBF); cerebral oxygen consumption, carbon dioxide excretion, and excess lactate; cerebral tissue adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP) and energy charge; and cerebral tissue water content. In the RCP10 group, there was excess cerebral lactate, and ATP and energy charge were low. In the RCP30 group, the water content of cerebral tissue was significantly higher than in other groups. In the RCP20 group, temperature was maintained in a narrow range, oxygen consumption and carbon dioxide excretion could be observed, there was no excess lactate, and ATP and energy charge were significantly higher than in the HCA group. In conclusion, RCP can provide adequate metabolic support for the brain during circulatory arrest, and a perfusion pressure of 20 mmHg is most appropriate for RCP.

Animals↗
PubMed1994

Premature termination mutations in two patients with deficiency of lactate dehydrogenase H(B) subunit.

Two patients with low lactate dehydrogenase (LD) activity were discovered during healthcare examinations and were found to be homozygous for LD-H (heart) subunit deficiency by electrophoretic isoenzyme analysis of serum and erythrocyte hemolysate. The molecular nature of the genetic mutations was characterized by amplification by the polymerase chain reaction and DNA sequencing. In one case, a single-base substitution (T-->G transversion) at codon 147 of the LD-H(B) gene resulted in a nonsense mutation; in the other case, a deletion of 2 base pairs had occurred at codon 139, resulting in a frameshift translation and premature termination.

Adult↗
PubMed1994

Pericardial cyst in the midline position.

Pericardial cysts are uncommon benign abnormalities and their incidence in mediastinal tumours is approximately 7%. The authors report the case of a 73-year-old man suffering from pericardial cyst in the midline position. The good results obtained following surgery are also reported.

Aged↗
PubMed1991

[A case report of resected double primary lung cancers in the same one segment].

A 68-year-old man with hypertension was admitted to the Shiga Kenritsu Seijinbyo Center for further examinations, because abnormal opacity in the right upper lung field was accidentally revealed by chest X-ray. Chest CT demonstrated two separate mass shadows, one 31 X 27 mm, the other 10 X 10 mm in size, both of which were located in the posterior segment of right lung. Specimens from transbronchial biopsy of the larger mass was histologically diagnosed as adenocarcinoma. He underwent right upper lobectomy with hilar and mediastinal lymph nodes resections. Postoperative patho-histological study showed the larger mass to be poorly differentiated adenocarcinoma, the smaller one, small cell carcinoma respectively, and no continuity between the two masses. Lymph nodes metastasis were negative. Any malignancy was not detected by brain CT, abdominal CT and any other gastro-intestinal examinations, and he was diagnosed to have double primary lung cancers in the same one segment. In this report, we discussed the diagnosis and treatment of double primary lung cancers, and reviewed the literatures.

Adenocarcinoma↗
PubMed1990

[Aortic valve replacement following percutaneous transluminal balloon valvuloplasty--a case report].

A 71-year-old female was operated on, because of massive aortic regurgitation following elective percutaneous transluminal balloon aortic valvuloplasty (PTAV) for calcified bicuspid aortic stenosis. The damaged aortic valve was successfully replaced with a 19 mm St. Jude Medical prosthetic valve. More careful consideration may be required in selection of the candidates of PTAV, as the procedure is not so satisfactory as reported in literatures concerning its efficacy and safety.

Aged↗
PubMed1990

[Surgical therapy of ruptured aortic aneurysm involving a Shuford type-3 right-sided aortic arch].

A 64-year-old man was admitted to our hospital with a complaint of severe back pain of sudden onset on Nov. 2, 1988. Aortogram and chest-CT demonstrated a ruptured dissecting aortic aneurysm involving a Shuford type-3 right-sided aortic arch. Emergency operation was done under temporary brachio-femoral arterial bypass. The thoracic aorta was transected distal to an aberrant left subclavian artery. The entry which located proximal to the aberrant subclavian artery was closed by two u-stay sutures with pledgets. The transected aorta was closed and reinforced with Sandwich method using Teflon-felt. The false lumen completely disappeared on chest-CT on 36th day postoperatively, and the patient is now doing well, although re-thoracotomy was necessary because of post-operative bleeding. To our knowledge, this is the first case of repair of a ruptured dissecting aortic aneurysm involving a right-sided aortic arch which is reported to be very rare.

Aortic Dissection↗
PubMed1990

[A case report of epicardial cryoablation in a five-month-old infant with WPW syndrome].

A five month old boy was referred to us with recurrent episodes of tachycardia and heart failure due to WPW syndrome. ECG and electrophysiological studies revealed a left lateral wall accessory conduction pathway. The patient did not respond to medical treatment and the division of the accessory pathway was performed by epicardial cryoablation methods through left lateral thoracotomy without using cardio-pulmonary bypass. Tachyarrhythmia and delta wave disappeared immediately following the operation and the patient had uneventful postoperative recovery. In this paper, the usefulness of epicardial cryoablation with left lateral thoracotomy for infants with a proved left accessory conduction pathway is stressed.

Cryosurgery↗
PubMed1989

[Re-operation for WPW syndrome due to recurrence of tachycardial attack].

A thirteen-year-old girl was admitted to our hospital because of tachycardial attack. Twelve years ago, she was diagnosed as WPW syndrome and division of accessory conduction pathway was performed at the other hospital, and it was described that the accessory pathway was located on the right lateral wall. ECG showed no delta wave nor PSVT postoperatively. But 12 years later, delta wave and PSVT reappeared. Operative treatment for recurrent tachycardial attacks was performed. Intraoperative pacing study revealed the right posterior-septal accessory pathway. It was divided and cryoablated. This paper reports an additional operation for the second accessory pathway of WPW syndrome.

Adolescent↗
PubMed1989

[Experimental study on the mechanism of serum leakage from expanded polytetrafluoroethylene (EPTFE) vascular prosthesis].

Even in recent years, the Blalock-Taussig (B-T) shunt operation has been carried out in order to increase pulmonary blood flow in patients of low pulmonary flow congenital heart disease. In such a case, a modified B-T shunt using an EPTFE vascular prosthesis would be employed in order to prevent blood flow obstruction in the upper extremity, and occasionally serum leakage from EPTFE vascular prosthesis is a complication. This has often troubled cardiovascular surgeons the world over, and we attempted to elucidate the mechanism of serum leakage and to discover how to prevent the situation from occurring. Using scanning electron microscopy, the structure of EPTFE vascular prosthesis was found to consist of an average of 0.5 micro meter polytetrafluoroethylene (PTFE) fibers arranged in parallel 5.0 micro meters from each other. The reason why serum does not usually leak from these widely spaced fibers is due to the presence of a repellent force derived from the surface tension and the contact angle between the solid surface of PTFE and the liquid. When the contact angle is over 90 degrees, the repellent force is in effect, while when it is below 90 degrees, this force is decreased. The surface tension and contact angle of physiological saline on the surface of PTFE showed values of 71.6 dyn/cm and 114.0 degrees, respectively, while demonstrating a strong repellent force. On the other hand, the surface tension of heparinized blood on the surface of the PTFE was 56.5 dyn/cm and the contact angle was 90.6 degrees. Thus, heparinized blood was assumed to act on the surface of the PTFE with a weak repellent force and for that reason had a tendency to easily leak from the EPTFE vascular prosthesis. When the surface of the PTFE was in contact with blood, blood protein was fixed to the surface of the PTFE and the contact angle of blood was thereby decreased. When the inner pressure of the vascular prosthesis was increased, the wall was stretched easily in a circumferential direction but with great difficulty in a longitudinal direction. With the PTFE stretched and released repeatedly, the expanded circumference was enlarged progressively due to the plastic character of the PTFE and because the spaces between the PTFE fibers were widened. In order to examine the relationship between the space between fibers and the critical pressure leading to serum leakage, computer simulation was carried out and the results showed a reversed linear correlation between the density of the fibers and the minimal pressures responsible for serum leakage.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

[A clinical experience of signs of compression in the neighboring organs after operation with Carpentier's method in dissecting aneurysm of the aorta].

A patient with a DeBakey IIIb type dissecting aneurysm of the aorta was treated with Carpentier's method. But after surgery the thromboexclusion procedure at the pseudo-lumen was insufficient. Fourteen months after surgery the left lung area suddenly became opaque, suggesting the possibility of impending rupture of the aneurysm. Therefore the patient underwent emergency surgery in which another permanent clamp was attached to the peripheral end of the aneurysm. After this operation, the aneurysm became reduced in size and the left lung inflated again, but an aorto-pulmonary fistula was formed 24 days later. After 6 months after second surgery, the patient began to experience dysphagia and dyspnea on exertion. Detailed examinations showed that these symptoms were caused by compression of the esophagus, bronchus and pulmonary artery by the permanent clamp. That is, this clamp, which possibly moved during organic change and size reduction of the aneurysm, seems to have compressed the adjoining organs enough to cause dysfunction. Such a compression of the neighboring organs can be regarded as one of problems originating from Carpentier's method, and shows that the procedure is not problem free yet.

Aortic Dissection↗
PubMed1988

Regional blood flow in the liver, pancreas and kidney during pulsatile and nonpulsatile perfusion under profound hypothermia.

Regional blood flow in the liver, pancreas and kidney was measured under conditions of profound hypothermia associated with total circulatory arrest, to determine whether cardiopulmonary bypass with pulsatile flow would improve the blood flow in these visceral organs in comparison with nonpulsatile flow. Using 56 adult mongrel dogs, total cardiopulmonary bypass was carried out to induce hypothermia and 40 min of total circulatory arrest was performed at 20 degrees C. After total arrest, the temperature was raised to 35 degrees C. With pulsatile flow, a decrease of the regional blood flow in the liver, pancreas and kidney was prevented during cooling, especially at 20 degrees C before total circulatory arrest. Moreover, regional renal blood flow recovered rapidly with pulsatile flow after total arrest at 20 degrees C, while after arrest with nonpulsatile flow blood flow in the kidney could not be measured in the cortex and was significantly lower in the medulla. In summary, pulsatile flow improves the hepatic, pancreatic and renal blood flow and, referring to our previous experiments, protects the function of these organs during cardiopulmonary bypass associated with profound hypothermia and total circulatory arrest.

Animals↗
PubMed1986

Radical surgical cure of Wolff-Parkinson-White syndrome: the Kanazawa experience.

Between 1973 and 1983, we operated on 160 patients with Wolff-Parkinson-White syndrome at Kanazawa University Hospital; 126 had Wolff-Parkinson-White syndrome alone, and 34 had combined cardiac diseases. Of the 160 patients, 140 were completely cured; postoperatively, they had no delta wave on electrocardiograms and no tachycardia attacks. In 11 patients, the delta wave reappeared an average of 56 days after operation. They, and three other patients with concealed Wolff-Parkinson-White syndrome, experienced several postoperative episodes of tachycardia. However, in 12 of the 14 patients with postoperative tachycardia attacks, these disappeared completely in the course of a long follow-up period and these patients are also considered to be cured symptomatically. In the two remaining patients, the tachycardia attacks persisted. Of the 126 patients with Wolff-Parkinson-White syndrome alone, none died as a direct result of the operation. Patients with combined cardiac diseases other than cardiomyopathy, mild Ebstein's anomaly, or venous abnormality were treated in one operation. Six of the 34 patients with combined cardiac diseases died. In none of the 160 patients was the His bundle intentionally interrupted as an alternative method of interrupting the accessory conduction pathway. Our study showed that life-threatening arrhythmias occur more often than expected in patients with Wolff-Parkinson-White syndrome and the tolerance for tachycardia attacks differs from patient to patient. Because the surgical treatment of Wolff-Parkinson-White syndrome is safe and reliable, as indicated in this report, the radical correction of this disease should be considered in carefully evaluated patients.

Adolescent↗