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Biomedical subjects

M Tsubota

Publications and source records attributed to M Tsubota.

At least 37 records · Page 2Linked to original sources
PubMed1996

Advantages of using the midline incision right retroperitoneal approach for abdominal aortic aneurysm repair.

This study was conducted to compare the midline incision right retroperitoneal approach for repairing abdominal aortic aneurysms (AAA) with the transperitoneal approach. The intra- and postoperative course of 15 patients who underwent AAA repair using the transperitoneal approach between 1987 and 1991 and another 15 patients who underwent AAA repair using the retroperitoneal approach between 1991 and 1994 were evaluated. The incidence of postoperative wound complications was also assessed. There was no operative or hospital death in either group. Although a significantly longer interval was required from the incision to the aortic clamp using the extraperitoneal method, there were no statistical differences in the aortic clamping time, total operation time, or blood loss between the two groups. On the other hand, there was a statistically significant improvement in bowel function and a significant reduction in the length of postoperative hospitalization following the extraperitoneal procedure. Furthermore, no wound complications such as those associated with the left flank incision developed after the extraperitoneal procedure. Thus, we recommend the midline incision right retroperitoneal approach for AAA as it does not involve muscle division and is associated with fewer complications.

Aged↗
PubMed1995

A new nucleophilic ring opening of an activated cyclopropane and a formal synthesis of (+/-)-carbovir.

The reaction of bicyclo[3.1.0]hexane 1, possessing a doubly activated cyclopropane ring, with acetic acid and potassium acetate in DMSO proceeded smoothly to give the adduct 2 in good yield. A formal total synthesis of the potent anti-HIV agent (+/-)-carbovir (9) was done by converting 2 into a known precursor 8 in 8 steps via allyl alcohol 7 including the regioselective introduction of a double bond (4 to 5) and attachment of the nucleobase using the Mitsunobu reaction (7 to 8).

Antiviral Agents↗
PubMed1995

[A successfully treated case of thoracoabdominal aortic aneurysm complicated with the coagulation disorder].

We could performed the safe operation for thoracoabdominal aortic aneurysm complicated with pre-DIC. A diagnosis of pre-DIC was made by laboratory data. Low heparin pretreatment was performed for the short term because we presumed the cause for pre-DIC was thromboses in aneurysm. That treatment was effective for the temporal remission of pre-DIC. In addition, during partial ECC low heparin (1 mg/kg) and nafamostat mesilate (2 mg/kg/h) were used. As a result, during and after the operation blood loss was a little. In summary heparin pretreatment is useful therapy for DIC and pre-DIC in aortic aneurysm patients.

Aged↗
PubMed1995

Long-term outcome of operative treatment of focal atrial tachycardia.

BACKGROUND: This study examined the long-term clinical outcome of patients with focal atrial tachycardia who were treated surgically. Focal atrial tachycardia is a relatively rare arrhythmia that is often difficult to control with conventional medical therapy. Therapeutic modalities are not well defined because of the scarcity of long-term data of treated patients, including pathologic findings. STUDY DESIGN: Nine patients, six men and three women, ranging in age from 16 to 50 years (mean of 34 +/- 14 years), underwent operative treatment for focal atrial tachycardia. The average rate of tachycardia was 167 +/- 22 beats per minute. All patients were treated with antiarrhythmic drugs (mean 2.9 drugs per patient). Concomitant operative procedures were performed upon four patients, including division of the accessory atrioventricular pathway for the Wolff-Parkinson-White syndrome in two patients, plication of the right atrium for idiopathic right atrial dilatation in one patient, and a closure of the atrial septal defect in one patient. Focal ablation was performed in all instances. RESULTS: There was no early or late death nor postoperative complications. Atrial tachycardia disappeared and there were no episodes of recurrent tachycardia postoperatively during the mean follow-up period of 67 +/- 38 months. Histopathologic findings from four patients revealed a sinus node-like structure, diffuse chronic epimyocarditis, focal myocarditis, and fascicular disarray lesions. CONCLUSIONS: Excellent long-term result were obtained in patients with focal atrial tachycardia who were treated operatively. Early operative intervention is preferable before the occurrence of impaired ventricular function. From the histopathologic findings, operative therapy should be selected in patients with diffuse atrial lesions.

Adolescent↗
PubMed1994

Surgical treatment of Wolff-Parkinson-White syndrome in infants and children.

Electrophysiologic features and surgical results were examined in 55 pediatric patients who underwent surgical accessory pathway division for Wolff-Parkinson-White syndrome. There were 31 male and 24 female patients ranging in age from 4 months to 15 years (mean age, 9.8 +/- 4.2 years; 25 patients were less than 10 years old; 4 patients were less than 12 months). Eleven of these patients had associated congenital heart disease and underwent concomitant surgical procedures to treat those conditions. Preoperative effective refractory period of antegrade accessory pathways, the right atrium, atrioventricular node, and cycle length during reentrant tachycardia were shorter in pediatric patients than in adult patients. Antegrade accessory pathways showed right predominance more frequently in the pediatric group than in the adult group. Surgical techniques included an endocardial approach (an epicardial approach was used in 1 patient) and concomitant operation for combined heart disease. The early mortality rate was 3.6%, whereas no late deaths occurred during the follow-up period of 96.8 +/- 54.9 months (maximum follow-up, 205 months). The absolute cure rate was 92%. There were no significant differences in early and late mortality between pediatric and adult patients. Surgical treatment of the Wolff-Parkinson-White syndrome in pediatric patients is as safe and effective as in adults. Considering the potential complications from prolonged fluoroscopic exposure during catheter ablation, surgical division of accessory pathways in children is a promising modality for the treatment of Wolff-Parkinson-White syndrome in selected cases.

Adolescent↗
PubMed1994

Surgical treatment of arrhythmogenic right ventricular dysplasia: long-term outcome.

Eight male patients ranging from 15 to 51 years old (mean age, 36.3 years) underwent surgical treatment of ventricular tachycardia (VT) associated with arrhythmogenic right ventricular dysplasia. One patient had an associated left ventricular aneurysm. The earliest activation site was detected for 15 lesions, and delayed potentials were recorded during sinus rhythm in all patients. On the basis of the epicardial mapping, the origins of the VT foci in the right ventricle were resected. Cryoablation on the surrounding myocardium was performed. There were no surgical deaths or postoperative fatal complications. During long-term follow-up, there has been no recurrence of VT and no congestive heart failure in the 6 patients without left ventricular involvement. The 2 patients with LV involvement died late of either congestive heart failure or development of VT originating from the left ventricle. In conclusion, a surgical approach consisting of myocardial excision and cryocoagulation offers a curative treatment of VT associated with arrhythmogenic right ventricular dysplasia and yields excellent long-term results when the VT origin is well identified in the right ventricle.

Adolescent↗
PubMed1994

Myocardial coagulation by intraoperative Nd:YAG laser ablation and its dependence on blood perfusion.

To investigate whether the efficacy of intraoperative laser ablation therapy is affected by myocardial blood perfusion, we irradiated 11 canine hearts through the epicardium with a Nd:YAG laser (10, 20, and 30 J/mm2) using air as the medium. Compared coagulated myocardial depth, width, and volume obtained in the red beating heart was compared with those in the white nonbeating heart infused with 0 degrees C saline (cardioplegic model) via the coronary artery. Histologically, the macro- and microscopical findings were very similar. At each level of energy, the width and volume of red myocardium coagulated were significantly larger than those of white myocardium (P < 0.01). At 30 J/mm2, the depth of coagulation of red myocardium was significantly larger than that of white myocardium (P < 0.01). The coagulated volume of the white myocardium was about 60% of that of the red myocardium. Nd:YAG laser energy was absorbed by blood (red color = hemoglobin), and more energy was transferred in the higher temperature myocardium. During intraoperative Nd:YAG laser ablation, the presence of blood perfusion in cardiac tissue is thought to be an important factor affecting safe irradiation.

Animals↗
PubMed1994

Surgical treatment of ventricular tachycardia after surgical repair of tetralogy of Fallot. Relation between intraoperative mapping and histological findings.

BACKGROUND: The mechanism of ventricular tachycardia (VT) after correction of tetralogy of Fallot (TF) is poorly understood. The purpose of this study was to examine the histopathology of the arrhythmogenic area detected by intraoperative mapping. METHODS AND RESULTS: The patients were three men who underwent radical surgery for TF at age 3, 3, or 5 years, respectively. VT developed at 8, 9, or 11 years, respectively, after surgery, and shock developed during VT in every case. The ECG revealed monomorphic VT in two cases and polymorphic VT in one case. Induction of VT resulted in a wide left-axis deviation-pattern QRS with cycle lengths varying between 260 and 330 milliseconds. The VT origin was identified at the right ventricular outflow tract (RVOT). A radical operation was performed with the patient under cardiopulmonary bypass. On epicardial mapping, delayed activation of the RVOT was recorded during sinus rhythm, and clockwise circus movement of the macroreentry current during VT on the right ventricular free wall was documented in each case. The VTs were treated successfully by surgical resection and cryoablation of the myocardium. In every patient, histology of the myocardial specimens showed degeneration, adiposis, fibrosis, inflammatory cell infiltration, and scattered myocyte islets. These lesions corresponded anatomically to the area of myocardium in which delayed activation was evident during epicardial mapping. CONCLUSIONS: The results of this study indicate that patients with VT after radical correction of the TF have abnormal histopathological findings at the site of the prior right ventriculotomy scar. These lesions were noted within the region of delayed activation found during epicardial mapping and were found to be a part of the reentrant circuit.

Adult↗
PubMed1994

Surgical treatment of patients with Wolff-Parkinson-White syndrome and associated acquired valvular heart disease.

Between November 1973 and March 1993, 454 patients underwent surgical division of an accessory pathway. The surgical and electrophysiologic data for 15 of these patients who underwent concomitant operation for acquired valvular heart disease were examined. This subgroup consisted of 10 male and 5 female patients whose ages ranged from 11 to 62 years (mean 51.6 +/- 9.7 years). The primary surgical indication was congestive heart failure in all cases; a concomitant history of cardiopulmonary resuscitation was present in two cases. Nine of these patients had mitral valve disease, three had aortic valve disease, two had combined aortic and mitral valve disease, and one had tricuspid valve disease. The surgical technique used for the treatment of Wolff-Parkinson-White syndrome included (1) an endocardial approach with the use of cardioplegic arrest, (2) a sharp dissection of the involved valve anulus, and (3) cryoablation. Concomitant surgical treatments of valvular heart disease included open mitral commissurotomy in five cases, mitral valve replacement in four cases, aortic valve replacement in three cases, aortic valve replacement with mitral valve commissurotomy in two cases, and tricuspid valvuloplasty (De Vega technique) in one case. Other concomitant surgical procedures included tricuspid annuloplasty with atrialized right ventricle and replacement of the ascending aorta in one case and left ventricular myectomy for hypertrophic obstructive cardiomyopathy in one case. No early deaths occurred. A successful disappearance of the delta wave and episodes of recurrent tachycardia were achieved in all 15 patients. Long-term surgical follow-up, averaging 86.2 +/- 54.8 months also demonstrated no late instances or recurrence of either a delta wave or tachycardia.

Adolescent↗
PubMed1994

[Two cases of tuberculous constrictive pericarditis].

Case 1 was a 79-year-old male suspected of tuberculous constrictive pericarditis. He was admitted to our hospital because of surgical treatment. His heart failure was NYHA IV. Culture of pleural effusion and pericardial effusion was negative. But ADA level in pericardial effusion was found to be increased. So tuberculosis was suspected. Cardiac catheterization date was compatible with constrictive pericarditis. Case 2 was a 73-year-old female. She was admitted because of heart failure (NYHA IV). As RVP wave indicated dip & platou at cardiac catheterization, she was diagnosed as constrictive pericarditis. ADA level in pleural effusion increased. So tuberculosis was suspected as etiology of constrictive pericarditis. In both cases, after pericardiectomy, heart failure improved to NYHA I. Results of pathological examination were tuberculous inflammation.

Aged↗
PubMed1993

[A case of anterior mediastinal mature teratoma containing air because of penetration to the lung].

A case of anterior mediastinal mature teratoma containing air because of penetrating to the lung was reported. The patient was a 28-year-old woman. The chest X-ray film on admission showed a homogeneous mass in the anterior mediastinum. This shadow changed to cystic one after ten days later. The tumor was removed together with adhering part of the left lung and pericardium through median sternotomy. Histologically, the wall of cysts contained sebaseous glands, bronchial glands and pancreatic tissue containing both exocrine and endocrine elements.

Adult↗
PubMed1993

[Injury of pulmonary artery and intrathoracic artery--a surgical case report].

The patient was a 52-year-old man. Tube drainage was performed to the right traumatic hemothorax. Then, 2,000 ml of blood flowed out and bleeding stopped for a time. Four hours later after injury, massive bleeding occurred again. So emergency thoracotomy was performed and we found a laceration in the main pulmonary artery and injury of intrathoracic artery. Pulmonary artery disruption from blunt chest trauma is rare. Further discussion was made by reviewing the related literature.

Accidents, Traffic↗
PubMed1992

Comparative study of eight sets of ECG criteria for the localization of the accessory pathway in Wolff-Parkinson-White syndrome.

Eight sets of electrocardiographic (ECG) criteria for the localization of accessory conduction pathway (ACP) were evaluated on 182 patients with a single ACP. The Rosenbaum criteria identified 78.6% of the left-sided and 94.0% of the right-sided ACPs. Four of the other seven sets of criteria demonstrated a sensitivity higher than 70.9% and six showed a specificity higher than 74.9% in the 4-region ACP localization. The ECG feature of the delta wave polarity in lead V1 correctly localized the ACP to one of three broad regions in 162 of 182 patients with an overall specificity of 94.5%. The study indicates that (1) the 12-lead ECG is of practical value for initial ACP localization; (2) a type A ECG is almost invariably associated with a left-sided ACP, while type B may occur with any ACP location; (3) the polarity of the delta wave is the most important ECG feature, and the polarities of the delta wave and main QRS complex in lead V1 play an important role in ACP localization.

Adult↗
PubMed1992

Structural analysis of nucleic acids by precise denaturing gradient gel electrophoresis: I. Methodology.

A method to convert the conventional denaturing gradient gel electrophoresis into a highly reproducible experimental system was developed. It was based on the following experimental findings; (i) dyes, which are small molecules, do not exhibit mobility changes attributed to their conformational change while nucleic acids do; and (ii) most of the mobility shifts caused by experimental fluctuations could be cancelled by normalizing the mobility of a sample with respect to the corresponding one of a dye. The method involves co-migration of internal reference dyes with samples (nucleic acids), and computer-aided data processing, allowing us to obtain the relative mobility of nucleic acids with respect to a dye throughout the denaturing gradient. The overall pattern of the relative mobilities thus obtained, named the normalized mobility profile (NMP), corresponded well to conformational changes of a macromolecule induced by denaturing effects. This method provides us with objective data without using internal macromolecular references, which not only guarantees the precision but also extends the range of application of the denaturing gradient method.

Base Sequence↗