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Biomedical subjects

S Shimokawa

Publications and source records attributed to S Shimokawa.

At least 37 records · Page 2Linked to original sources
PubMed2001

Three-dimensional magnetic resonance imaging of lung and liver tumors in mice by use of transversal multislice magnetic resonance images.

PURPOSE: To diagnose lung and liver tumors experimentally induced in mice in three-dimensional magnetic resonance (MR) images constructed by superimposing transversal multislice MR images of thoracic and abdominal regions taken under a high magnetic field of 7.05 tesla (T). METHODS: Lung and liver tumors were induced by administration of urethane to A/J mice and implantation of transplantable colon-26 cells into BALB/c mice, respectively. Two-dimensional (2-D) multislice MR images from the thoracic to abdominal regions were taken under the proton density-weighted conditions. Each organ in the 2-D MR images was pseudocolored, and a three-dimensional (3-D) image was constructed by superimposing them on a UNIX computer, using volume-rendering software. RESULTS: In the normal mouse, each organ in the thoracic and abdominal regions was three-dimensionally imaged and was clearly distinguished from the others. In mice with tumors in the lung or liver, the pathologic changes in the tissue could be visualized in 3-D images. CONCLUSIONS: The MR images three-dimensionally constructed by use of a method combining MR imaging under a high magnetic field of 7.05 T and a computer technique using volume-rendering software was useful for diagnosis of lung and liver tumors experimentally induced in mice.

Abdomen↗
PubMed2000

Involvement of the right atrium by malignant lymphoma as a cause of right cardiac failure: report of a case.

We describe herein a rare case of malignant lymphoma occupying almost the entire space of the right atrial cavity and causing low cardiac output syndrome. A life-saving emergency operation was carried out after the establishment of a temporary bypass between the axillary and femoral veins to prevent exacerbation of the patient's condition during the induction of anesthesia. Cardiopulmonary bypass was commenced and the right atrium was opened. A large tumor in the right atrium could not be completely removed due to invasion of the atrial wall. A bypass from the left innominate vein to the pulmonary arterial trunk was constructed with a prosthetic graft to convert the blood flow directly from the systemic vein to the pulmonary artery. Postoperative radiation treatment was given, which resulted in reducing the size of the tumor considerably, and the patient is doing well 1 year after his operation.

Blood Vessel Prosthesis Implantation↗
PubMed2000

The influence of human T lymphotropic virus type I infection on the outcome of cardiovascular surgery.

OBJECTIVE: Human T lymphotropic virus type I infects CD4(+) T cells and affects cell-mediated immunity. Cardiopulmonary bypass transiently alters lymphocyte subsets, resulting in a reduction in CD4(+) T cells and an increase in CD8(+) T cells. We proposed that cardiovascular operations and human T lymphotropic virus type I infection may act synergistically, resulting in serious damage to cell-mediated immunity. METHODS: A total of 517 consecutive patients who were preoperatively screened for anti-human T lymphotropic virus type I antibody and underwent cardiovascular operations with cardiopulmonary bypass were enrolled in this study. Of the 517 patients, 82 (16%) had positive test results for anti-human T lymphotropic virus type I antibody. The surgical outcome of patients with positive and negative results for anti-human T lymphotropic virus type I antibody was analyzed retrospectively. RESULTS: There was no difference between the 2 groups with respect to early mortality. Distribution of survival curve was also not significantly different (P =.5; mean follow-up duration, 2.4 +/- 1.8 years [range, 0-9.4 years] and 3.2 +/- 2.8 years [range, 0-9.8 years]) in the groups with positive and negative antibody results, respectively). In particular, long-term follow-up did not reveal adult T-cell leukemia or human T lymphotropic virus type I-associated myelopathy, and occurrence of neoplasm did not differ between groups. Early infectious complication was, however, significantly higher in the group with positive antibody results than in the group with negative results (P =.02). Logistic regression analysis revealed human T lymphotropic virus type I infection as a significant risk for this complication (P =.04; odds ratio, 2.5; 95% confidence interval, 1. 0-5.8). CONCLUSION: A combination of human T lymphotropic virus type I infection and cardiovascular operation is believed to increase the potential risk of infectious complications shortly after the operation. However, this synergistic effect seems to be transient and has little influence on long-term prognosis.

Aged↗
PubMed2000

Preoperative autologous donation of blood for a simple cardiac anomaly: analysis of children weighing under twenty kilograms.

OBJECTIVE: Preoperative autologous donation of blood has been expanded to cardiac operations in children. However, because of problems such as lack of cooperation and hemodilution during cardiopulmonary bypass, its efficacy in small children is unclear. This study clarifies the clinical significance of preoperative autologous donation of blood in small children. METHODS: Thirty-seven patients weighing under 20 kg (age range, 3-9 years; weight range, 13-20 kg) underwent preoperative autologous donation and cardiac operations to treat a simple anomaly. Twenty-five age- and weight-matched patients who were not cooperative or refused preoperative autologous donation served as control subjects. Autologous blood was collected by the simple or leapfrog method and stored as blood components. Each collecting volume was 5 to 10 mL/kg. RESULTS: The donation was performed 6+/-2 times during 50+/-16 days, and the whole storage volume was 48+/-17 mL/kg. There was no serious complication. The minimum hematocrit level negatively correlated with the priming volume of cardiopulmonary bypass (preoperative donation patients: P<.01, r(2) = 0.4; control subjects: P =.5, r (2) = 0.03). Blood loss did not significantly differ between preoperative donation patients and control subjects, and the transfused blood volumes were 43+/-13 mL/kg and 29+/-22 mL/kg, respectively. All of the autologous blood products but fresh frozen plasma were reinfused. Use of homologous blood was significantly less in preoperative donation patients than in control subjects (0% vs 80%, P <.01). In preoperative donation patients postoperative recovery in hemoglobin level was significantly better, which is concurrent with a higher reticulocyte level. CONCLUSION: Preoperative autologous donation can be performed safely with clinical efficacy, even in children under 20 kg. This can be improved further through coupling with another procedure.

Analysis of Variance↗
PubMed2000

Intracranial dural metastasis of mediastinal seminoma--case report.

A 24-year-old male presented with a rare intracranial dural metastasis from a mediastinal germ cell tumor infiltrating the superior vena cava, pericardium, ascending aorta, and lung. Routine chest radiography incidentally revealed the abnormal mediastinum, which was partially resected after median sternotomy, followed by radiotherapy. One year after the radiotherapy, magnetic resonance imaging revealed a right parasagittal tumor mimicking a meningioma. Partial tumor removal was performed. Two cycles of chemotherapy with carboplatin and etoposide were then performed, and the residual tumor almost completely disappeared. The histological diagnosis of both the mediastinal and intracranial tumors was pure seminoma. Sections of metastatic tumor revealed several thick fibrous septa and numerous epithelioid granulomas infiltrated by plasma cells, intermingled between the clusters of tumor cells. Follow up of patients apparently in remission from mediastinal seminoma without evidence of advanced or recurrent disease at other sites is recommended.

Adult↗
PubMed2000

[Simultaneous operation for lung tumor and cardiovascular disease].

Successful simultaneous operation for lung tumor and cardiovascular disease was performed in three cases. A 76-year-old man with stage I lung cancer and ischemic heart disease underwent a partial lobectomy following single coronary artery bypass grafting through a median sternotomy. A 62-year-old man with stage I suspected lung cancer and thoracic aortic aneurysm underwent a partial segmentectomy before aneurysmectomy and patch closure using vascular prosthesis through a left posterolateral thoracotomy. These two cases were performed under extracorporeal circulation. A 69-year-old man with bronchogenic carcinoma and abdominal aortic aneurysm underwent a left upper lobectomy with standard lympho node dissection following aneurysmectomy and grafting using vascular prosthesis. As a simultaneous procedure, limited operation for lung tumor, especially for stage I non-small cell lung cancer, is acceptable for cases in using extracorporeal circulation. On the other hand, except emergency ruptured cases of abdominal aortic aneurysm, standard radical operation for lung cancer as a simultaneous procedure is preferred for cases such as lung cancer accompanied with abdominal aortic aneurysm without extracorporeal circulation.

Aged↗
PubMed2000

[Surgical treatment for malignant pleural mesothelioma in eight cases].

Between 1987 and March 2000, we have operated on eight patients for malignant mesothelioma which consisted of four of localized type and four of diffuse type. We have aggressively resected mesothelioma combined with chemotherapy whether the tumor was primary or recurrent, and concluded the following. 1) In localized malignant mesothelioma, en-bloc primary tumor resection was possible and additional resection for recurrence was effective and useful for long time survival. 2) In diffuse malignant mesothelioma, complete tumor resection was impossible to even perform pleuropneumonectomy accompanied with partial resection of pericardium and diaphragm and, therefore, the prognosis was poor in four patients and all died around one year. 3) Because recurrent pattern for localized type was diffuse type, diagnosis and surgical treatment in early stage was essential for long time survival.

Adult↗
PubMed1999

Application of a manifold system for temporary reperfusion during proximal anastomoses in conventional coronary bypass surgery.

We report the application of a manifold system which is attached to saphenous vein grafts after the completion of distal coronary anastomosis. This technique permits not only the direct delivery of cardioplegic solution into the distal coronary artery, but also the reperfusion of revascularized coronary arteries via saphenous vein grafts by changing the connection to the arterial circuit during proximal anastomosis under a partial occlusion of the aorta in conventional coronary artery bypass surgery.

Cardioplegic Solutions↗
PubMed1999

Repair of an acute type A dissection: fate of the remnant false lumen and preserved aortic valve.

From January 1992 through March 1997, 75 patients (DeBakey type I/II = 56/19) underwent a surgical repair of a type A acute dissection. The patients included 37 men and 38 women ranging in age from 23 to 83 years with a mean of 65 years. All patients were admitted to our hospital with a mean interval of 2.2 days from the episode of onset. The overall hospital mortality rate was 25% (19/75). There were three late deaths among the 56 patients discharged from the hospital. The actuarial survival rate for the patients surviving the operation was 87% at 5 years after repair. A subsequent aortic operation was necessary in 6 patients, while 3 other patients who had late aortic complications were put on medical therapy alone. As a result, the aortic event-free survival rate was 54% at 5 years. For a type I dissection the false lumen was completely thrombosed after repair in 34%. The descending thoracic aorta with a patent false lumen was markedly enlarged in proportion to the follow-up time. After a conservative approach to the aortic valve, all but one patient demonstrated an adequate valve function throughout this study period. This experience with a midterm follow-up showed an acceptable durability of the preserved aortic valve and a progressive enlargement of the persistent false lumen with a high rate of aortic complications. Hence, all patients with a type A dissection need a close follow-up to assess the aorta for complications of either recurrent or residual aneurysms and dissections.

Acute Disease↗
PubMed1999

Coronary artery aneurysm after stent implantation.

A coronary artery aneurysm that developed 6 months after coronary stent implantation in the left anterior descending artery, was treated by double coronary artery bypass grafting due to restenosis of the affected vessel and progression of right coronary artery stenosis. Although the poststenting aneurysm initially remained postoperative angiography showed that it had disappeared. In addition to thrombotic occlusion, another mechanism behind its disappearance may be that geometric changes of the implanted stent caused by heart retraction during surgery closed the entrance to the aneurysm.

Adult↗