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Biomedical subjects

C Yamashita

Publications and source records attributed to C Yamashita.

At least 19 recordsLinked to original sources
PubMed1999

Mild hypothermia for temporary brain ischemia during cardiopulmonary support systems: report of three cases.

Recovery without residual neurological damage after cardiac arrest with temporary cerebral ischemia is rare. Therefore, it is most important that every effort is made to prevent brain damage occurring immediately after successful cardiopulmonary resuscitation. We report herein the cases of three patients who suffered either cardiogenic or hypovolemic shock and were resuscitated by a cardiopulmonary support system followed by mild hypothermia. All three patients recovered completely without any neurologic damage. The outcomes of these three patients demonstrated that mild hypothermia may be important for cerebral preservation after cardiopulmonary resuscitation.

Aged↗
PubMed1999

Preventive influence of inhaled nitric oxide on lung ischemia-reperfusion injury.

In lung transplantation, lung ischemia-reperfusion injury is a serious problem when using long-term preserved grafts. A warm ischemic lung model was prepared using rabbits. NO was administered by inhalation (group I, n = 9). The control group was not administered NO (group II, n = 8). Severe ischemia-reperfusion injury occurred as evidenced by hypoxia and lung edema. PaO2 at 120 min after reperfusion was 325 +/- 41 mmHg in group I and 40 +/- 6 mmHg in group II. The pulmonary blood flow of the left lung at 120 min after reperfusion was 51% +/- 3% in group I and 20% +/- 5% in group II. The wet-to-dry weight ratio was 5.5 +/- 0.2 for the right lungs, 5.8 +/- 0.8 for the left lung in group I, and 6.1 +/- 0.4 for the left lung in group II. Histopathologically, marked hemorrhage, hyaline membrane formation, and leukocyte infiltration were observed in group II but not in group I. These data suggested that inhaled NO reduced warm ischemia-reperfusion injury in the lung, and also contributed to a better preserved lung function.

Administration, Inhalation↗
PubMed1999

Aortic valve replacement after retrosternal gastric tube reconstruction for esophageal cancer.

A 59-year-old man with a history of the thoraco-abdominal esophagus resection with retrosternal gastric tube reconstruction for esophageal cancer complicated by anastomosis leakage and purulent pericarditis was admitted for aortic regurgitation due to infective endocarditis. Floppy vegetation and worsening cardiac failure indicated aortic valve replacement. In a median sternotomy approach, the thickest adhesion between the cervical esophagus and posterior surface of the manubrium sternae was freed using an ultrasonic osteotome. Severe adhesions in the pericardium due to purulent pericarditis were found. Median sternotomy enabled minimal exposure of the aortic root, upper right atrium, and right superior pulmonary vein for instituting extracorporeal circulation and replacing the aortic valve. The patient's postoperative course was uneventful. For cardiac surgery in patients with a retrosternal gastric tube, left anterior or right thoracotomy may be considered to avoid gastric tube injury. Median sternotomy, however, is an alternative enabling safe heart exposure, and the ultrasonic osteotome was very useful in incising the sternum without injuring the cervical esophagus, which had no serosa.

Aortic Valve↗
PubMed1999

Valvular heart disease. A comparative study of results after primary operation, reoperation, and after multiple reoperation.

Reoperation for valvular heart disease has been associated with a higher operative mortality than primary operations, especially in patients who had multiple prior operations. We have analyzed the 226 consecutive patients who underwent valve replacement. These involved 163 primary operations, 52 first reoperation, and 11 second/third reoperations. Preoperative left ventricular dysfunction was more severe, and operation time and cardiopulmonary bypass time were significantly greater according to the number of operations, associated with a greater amount of intraoperative blood loss. The operative mortality after a second/third reoperation was 27.3%, which was significantly higher than that after primary operation (6.7%) (p < 0.05), and that after first reoperation (5.8%) (p < 0.05). Seven (64%) patients who underwent a second/third reoperation had poor preoperative left ventricular function (%FS < 25%), and 5 (71%) of these required postoperative mechanical supports, and 3 (60%) of the 5 patients died of low output syndrome. We have found that poor preoperative left ventricular function and the duration on cardiopulmonary bypass, but not the number of reoperation were correlated with operative mortality. Continued efforts should be directed to decrease the mortality for multiple reoperative valve surgery.

Adult↗
PubMed1999

Transaortic video-assisted removal of a left ventricular thrombus.

A mobile and pedunculated left ventricular thrombus was developed after acute myocardial infarction in a 59-year-old man, and was successfully removed surgically through the aortic valve using a video-assisted thoracoscope. Transaortic video-assisted thoracoscopy greatly facilitated exposure of the interior of the left ventricle and preserved left ventricular function by avoiding ventriculotomy.

Endoscopy↗
PubMed1999

Usefulness of postoperative percutaneous cardiopulmonary support using a centrifugal pump: retrospective analysis of complications.

Between January 1992 and December 1997, we employed percutaneous cardiopulmonary support (PCPS) using a centrifugal pump in 25 patients. In 21 of them, PCPS was used postcardiotomy. These patients could not be weaned from cardiopulmonary bypass due to profound ventricular failure. As for the other 4 patients, PCPS was used preoperatively for profound cardiogenic shock, a thrombosed valve, a stuck valve, and pulmonary embolization. Nine patients (43%) were weaned from PCPS (Group 1), and 3 (14%) were discharged from the hospital. The other 12 patients (57%) had perioperative extensive myocardial infarction and could not be weaned (Group 2). The causes of death were bleeding and multiple organ failure (MOF) associated with ventricular failure. The reasons for MOF were perioperative massive transfusion and hepatic congestion caused by sustained ventricular failure. To increase the survival rate, complete hemostasis and prevention of increased central venous pressure by early use of PCPS are necessary.

Acute Kidney Injury↗
PubMed1999

Structure, evolution, and liver-specific expression of sterol 12alpha-hydroxylase P450 (CYP8B).

The rat CYP8B cDNA encoding sterol 12alpha-hydroxylase was cloned and sequenced. The amino acid sequence of the heme-binding region of CYP8B was close to those of CYP7A (cholesterol 7alpha-hydroxylase) and CYP7B (oxysterol 7alpha-hydroxylase). Molecular phylogenetic analysis suggests that CYP8B and the CYP7 family derive from a common ancestor. The P450s of the CYP7 and CYP8 families, except for CYP8A (prostacyclin synthase), catalyze the oxygenation of sterols from an alpha surface in the middle of the steroid skeleton. These facts suggest that CYP8B is a P450 closely linked to those of the CYP7 family. CYP8B was expressed specifically in liver. Hepatic CYP8B mRNA level and the 12alpha-hydroxylase activity were altered by cholestyramine feeding, starvation, streptozotocin-induced diabetes mellitus, and administration of clofibrate, dexamethasone or thyroxin, indicating the pretranslational regulation of CYP8B expression. The enhanced CYP8B mRNA expression in streptozotocin-induced diabetic rats was significantly decreased by insulin within 3 h of its administration. These facts demonstrate a regulatory role of insulin in CYP8B expression as a suppressor.

Amino Acid Sequence↗
PubMed1999

Usefulness of cardiopulmonary bypass in reconstruction of inferior vena cava occupied by renal cell carcinoma tumor thrombus.

UNLABELLED: Aggressive surgical treatment in renal cell carcinoma is still controversial. The aim of this paper is to assess inferior vena caval (IVC) reconstruction for suprahepatic vena caval renal cell carcinoma (RCC) tumor thrombus. Twelve patients with suprahepatic vena caval thrombus from renal cell carcinoma who underwent surgical repair with cardiopulmonary bypass were evaluated. The vena caval defect was reconstructed by direct suture, patch repair, or graft replacement. Of 12 patients undergoing partial cardiopulmonary bypass, tumor thrombus extended to the junction of the hepatic vein in three patients and to the right atrium in one. Tumor thrombus was removed manually or with balloon catheter. Tumor thrombus in the right atrium was removed during electrical ventricular fibrillation. Repair of the IVC was performed by direct suture of the IVC wall in two patients, patch repair with expanded polytetrafluoroethylene (EPTFE) graft in seven, and graft replacement with an EPTFE graft in three. There were no operative deaths and the only postoperative complication was one patient death from pulmonary emboli. The four patients with nonlocalized disease died within 2 years, but four patients lived for more than 3 years postoperatively. Survival was 37.5% at 3 years and 18.8% at 5 years by the Kaplan-Meier's method. CONCLUSIONS: (1) Partial cardiopulmonary bypass is useful for the control of bleeding when tumor thrombus in the IVC extends to the junction of the hepatic vein. (2) Nephrectomy with tumor thrombectomy of the IVC is valuable, and long-term survival is possible in patients without distant metastases or regional lymph node metastases.

Adult↗
PubMed1999

Efficacy of initial controlled perfusion pressure for ischemia-reperfusion injury in a 24-hour preserved lung.

In lung transplantation, the safety period of the ischemic time of the graft is within 6 hours. Because of the problem of donor shortage, it is essential to extend the safety period of the preservation time of the donor lung. However, the longer the preservation time is, the more severe is the resulting ischemia-reperfusion injury. This study was designed to evaluate the efficacy of initial controlled perfusion pressure in the reduction of ischemia-reperfusion injury in a 24-hour preserved lung. Japanese white rabbit lungs were flushed with a low-potassium dextran solution (4C, 500 ml) after injection of prostaglandin E1 (20 microgram, bolus via PA) and submersed in the same solution for 24 hours at 4C. After preservation, the left lung was reperfused using an extracorporeal lung perfusion model which comprised of a closed circuit combined with a membrane deoxygenator. Assessment of lung function included gas analysis of influent and effluent blood and mean pulmonary artery perfusion pressure. Then the lung wet/dry weight ratio was calculated. In group I of the control group (n=6), the left lung was reperfused immediately following flushing (without preservation) at a flow rate of 50 ml/min for 60 minutes. In groups II and III, grafts were stored for 24 hours. In group II, grafts (n=6) were reperfused at a flow rate of 50 ml/min for 60 minutes. In group III (n =6), the flow rate was controlled by maintaining the perfusion pressure below 30 mmHg during the initial 5 minutes and was increased to 50 ml/min for the subsequent 60 minutes. In group II, the mean pulmonary artery pressure during perfusion increased rapidly, and oxygenation deteriorated. All grafts developed pulmonary edema within 12 minutes after reperfusion. Examination of the specimen revealed that the peripheral lung was not perfused. In group III, the mean pulmonary artery perfusion pressure was maintained below 30 mmHg, and oxygenation was preserved sufficiently throughout the experiment (delta PO2 > 100 mmHg) with no significant difference from control values. In conclusion, ischemia-reperfusion injury of the 24-hour preserved lung was attenuated prominently by controlling initial perfusion pressure for 5 minutes.

Analysis of Variance↗
PubMed1999

The effect of direct lidocaine injection into the clamped aortic segment on the spinal evoked potential: early diagnosis for spinal cord ischemia.

PURPOSE: The aim of this study was to identify a method to determine whether segmental artery reconstruction was indicated during aortic clamping. METHOD: Spinal cord evoked potential (SCEP) and regional spinal blood flow were studied in 24 adult dogs. Using the left heart bypass technique, aortic clamping divided the aorta into thoracic, abdominal, and terminal segments. After the occlusion of the descending aorta and discontinuation of the perfusion to the abdominal segment, animals were assigned to four groups: no treatment with perfusion to the terminal aorta (group IA), no treatment with cessation of bypass (group IB), 5% lidocaine administration (5 mg/kg) into the abdominal segment with perfusion to the terminal aorta (group IIA), and lidocaine administration with cessation of bypass (group IIB). RESULTS: Cessation of bypass reduced spinal blood flow and SCEP amplitude. Lidocaine injection allowed for a significant rapid decrease in SCEP amplitude in group IIB compared with group IB (24.2% +/- 13.4% versus 92.3% +/- 33.2%; p = 0.0039). The degree of spinal blood supply was reflected immediately in the magnitude of SCEP amplitude change by the direct lidocaine injection. (group IB versus group IIB; p = 0.023). CONCLUSION: The direct injection of lidocaine into the clamped aorta results in a rapidly change in SCEP in the threat of ischemia and can be used to make an early detection of the segmental arteries perfusing to the spinal cord.

Analysis of Variance↗
PubMed1998

Role of endogenous endothelin in the development of graft arteriosclerosis in rat cardiac allografts: antiproliferative effects of bosentan, a nonselective endothelin receptor antagonist.

BACKGROUND: The purpose of this study was to determine whether endothelin-1 (ET-1) contributes to the development of graft arteriosclerosis and whether the orally active nonpeptide endothelin receptor antagonist bosentan, which blocks both ETA and ETB receptors, can protect against this pathologic damage. METHODS AND RESULTS: Recipient male Lewis rats were divided into three groups; group 1 received heterotopic heart transplantations from Lewis donors and groups 2 and 3 received transplantations from Brown-Norway donors; group 3 recipients also received bosentan orally at the dose of 20 mg/kg per day for 120 days. All recipients were given cyclosporine and were euthanized at examination 120 days after transplantation. Plasma ET-1 levels were significantly higher in group 2 than in group 1 (6.99+/-0.91 and 4.15+/-.83 pg/mL, respectively). Strong ET-1 immunoreactivity was seen in both the thickened neointima and the media of the coronary arteries in group 2 but not in group 1. The mean ratio of the coronary luminal area to the total vascular area in group 2 (19.0+/-11.7%) was significantly lower than that in group 1 (34.2+/-9.9%) and was significantly increased in group 3 (33.2+/-9.2%). CONCLUSIONS: These results show that local upregulation of ET-1, mainly in the thickened neointima and the media of the coronary arteries, may play an important role in the pathogenesis of graft arteriosclerosis by stimulating ETA receptors, ETB receptors, or both. Orally active bosentan might be a useful agent for the clinical prevention of graft arteriosclerosis.

Actins↗
PubMed1998

Successful surgical treatment of an Edwards type IIIB right aortic arch aneurysm: report of a case.

A true aneurysm of the right aortic arch which accompanies various branching characteristics is very rare. We report herein the successful surgical treatment of an elderly patient found to have an Edwards type IIIB right aortic arch aneurysm encircling and compressing the trachea. The complete right aortic arch and right subclavian artery were reconstructed through the inside of the aneurysm using selective cerebral perfusion. The patient recovered well, with no residual neurologic deficit and with resolution of the dyspnoic attacks he had suffered preoperatively.

Aortic Aneurysm, Thoracic↗
PubMed1998

Repeat tricuspid valve replacement for acquired valvular heart disease: report of a case.

A patient was admitted to our hospital for investigation of exertional dyspnea and liver dysfunction, 10 years after undergoing mitral valve replacement (MVR) and tricuspid valve replacement (TVR) using a Bjork-Shiley mechanical valve and a Carpentier-Edwards bioprosthesis, respectively. Echocardiographic examinations, magnetic resonance imaging (MRI), and cardiac catheterization subsequently revealed severe degenerative changes of the artificial tricuspid valve. Thus, a repeat TVR with plication of his enlarged right atrium that was compressing the right lung was performed. The extracorporeal circulation was adjusted so that the oxygen saturation of the hepatic vein was maintained above 50% to prevent liver damage. The patient had a good postoperative course and has encountered no further problems since his discharge from hospital.

Female↗
PubMed1998

Pulmonary circulatory parameters as indices for the early detection of acute rejection after single lung transplantation.

We investigated the relationship between the changes in the pulmonary blood flow and histology during acute rejection following single lung transplantation. In single lung transplantation using adult mongrel dogs, immunosuppression with cyclosporine and azathioprine was discontinued after postoperative day 14 to induce rejection. Doppler flow probes were placed adjacent to the ascending aorta and the left pulmonary artery to measure the blood flow on a daily basis. In addition, chest roentgenograms were also examined daily. The pulmonary pressure was measured using a Swan-Ganz catheter prior to and following the induction of rejection. Open lung biopsies were performed when the left pulmonary artery flow decreased to half of the prerejection value. The pulmonary artery flow decreased to 14.3% of the aortic flow 5 days after the discontinuation of immunosuppression. The graft pulmonary vascular resistance increased significantly compared to the prerejection values (P < 0.001). This was not accompanied by any abnormalities on chest roentgenography. The histology was consistent, with marked perivascular lymphocytic infiltration with little alveolar or interstitial changes. During rejection, the increased pulmonary vascular resistance in the graft was probably the result of perivascular inflammatory cell infiltration, which was seen prior to changes on chest roentgenography. Changes in the left pulmonary artery flow and histology thus appear to be closely correlated in the early stages of acute rejection.

Animals↗
PubMed1998

Impact of retrograde cerebral perfusion with posterolateral thoracotomy on distal arch aneurysm repair.

BACKGROUND: Repair of distal aortic arch aneurysms is difficult to accomplish through a median sternotomy or left thoracotomy, and stroke and respiratory disorders often become lethal complications with the use of circulatory arrest. We investigated the use of retrograde cerebral perfusion with a posterolateral thoracotomy in the repair of distal arch aneurysms. METHODS: Thirty-eight patients underwent repair of a distal arch aneurysm. They were divided into three groups according to the method of surgical repair used. Sixteen patients (group I) underwent proximal anastomosis of the graft with the use of an aortic cross-clamp. Eight patients (group II) underwent open proximal anastomosis with the use of retrograde cerebral perfusion (oxygenated blood perfusion through a superior vena cava cannula) and a median sternotomy and anterolateral thoracotomy. Fourteen patients (group III) also underwent open anastomosis with the use of retrograde cerebral perfusion (cerebral perfusion through blood returned to the right atrium with the patient in the Trendelenburg position) and a posterolateral thoracotomy. RESULTS: The operative mortality rate in group I was 25.0%; 4 of 16 patients died of stroke, myocardial infarction, and intestinal necrosis. In group II, 3 of 8 patients (37.5%) died of respiratory failure and aortic dissection. In group III, only 1 of 14 patients (7.1%) died, as a result of heart failure. CONCLUSIONS: The use of retrograde cerebral perfusion with a posterolateral thoracotomy is an alternative method that minimizes the risk of stroke and respiratory failure during distal aortic arch operations.

Adult↗
PubMed1998

Surgical treatment for transvenous tumor extension into the heart: four cases.

From 1984 to 1996, four patients with transvenous intracardiac tumor extension underwent operations in the Kobe University Hospital. The primary tumors of two were intravenous leiomyomatoses originating from the uterus; a third patient had invasive thymoma, and the fourth patient had clear cell sarcoma of the kidney. In 1985, one patient had a curative, staged resection. One-stage operations were carried out in three patients, and all intracardiac tumors were successfully resected en bloc with the primary tumors under conditions of electrical ventricular fibrillation and mild hypothermia. Combined venous reconstructions were necessary for en bloc resection in three cases. Two patients with malignancy received postoperative chemoradiotherapy, and all four patients were discharged uneventfully from our hospital. We consider radical resection with curative intent only for patients with tumors extending into the heart. In these cases, a one-stage operation is preferable, and electrical ventricular fibrillation with mild hypothermia is a recommended method of circulatory assist because of its simplicity.

Adult↗
PubMed1998

Neonatal erythema infectiosum.

A report is presented of a patient with neonatal erythema infectiosum who developed petechiae, transient thrombocytopenia and transient cardiac failure due to transplacental transmission of human parvovirus B19 (HPV B19) infection. It is suggested that the thrombocytopenia was caused by platelet-associated IgG produced by the patient, and that the cardiac failure may have been caused by direct entry of HPV B19 into the cardiac tissue.

Adult↗