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Biomedical subjects

T Sasajima

Publications and source records attributed to T Sasajima.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Surgical management of chest wall tumors].

Twenty-four patients with chest wall tumors underwent resection during the past twenty years. There were 12 female and 12 male patients with ages ranging from 7 months to 78 years (mean 44 years). Five patients had primary malignant neoplasms, 7 had metastases, and 12 had benign tumors. The tumor was located in the soft tissue in 14 patients and in the ribs and the sternum in 10. Ninety-two percent of tumors were diagnosed correctly if they were benign or malignant before resection, however the final diagnosis was made in only 25% of benign tumors and 54% of malignant tumors before surgery. Thirty-one operations were performed in 24 patients and 10 reconstruction with prosthetic materials were done. Concerning malignant neoplasms patients with primary tumors had better prognosis than those with metastases and patients underwent reconstruction had better prognosis than those underwent resection only. We conclude that wide resection with reconstruction is potentially curative treatment.

Adolescent↗
PubMed1999

[A case of tracheal fistula after operation for esophageal cancer].

We have experienced a case of mediastinal abscess and tracheal fistula after operation for esophageal cancer and successfully closed by using intercostal muscle pedicle flap. A 61-year-old male underwent esophagectomy for advanced esophageal cancer. On the 12th postoperative day, mediastinal abscess caused by leakage was detected, and drainage of the mediastinal and thoracic cavity was performed. On the 29th postoperative day, tracheal fistula was detected, and operation was performed in order to close the fistula by using of intercostal muscle pedicle flap. His postoperative course was fair and general condition was improvement, esophageal reconstruction using of free jejunal graft was performed and oral ingestion was started.

Aged↗
PubMed1998

Imaging herpes virus thymidine kinase gene transfer and expression by positron emission tomography.

We report a series of studies that assess the feasibility and sensitivity of imaging of herpes virus type one thymidine kinase (HSV1-tk) gene transfer and expression with [124I]-5-iodo-2'-fluoro-1-beta-D-arabinofuranosyluracil ([124I]-FIAU) and positron emission tomography (PET) and the ability of [124I]-FIAU-PET imaging to discriminate different levels of HSV1-tk gene expression. Studies were performed in rats bearing multiple s.c. tumors derived from W256 rat carcinoma and RG2 rat glioma cells. In the first set, we tested the sensitivity of [124I]-FIAU-PET imaging to detect low levels of HSV1-tk gene expression after retroviral-mediated gene transfer. HSV1-tk gene transduction of one of preestablished wild-type W256 tumor in each animal was accomplished by direct intratumoral injection of retroviral vector-producer cells (W256-->W256TK* tumors). Tumors produced from W256 and W256TK+ cells served as the negative and positive control in each animal. Highly specific images of [124I]-FIAU-derived radioactivity were obtained in W256TK* tumors (that were transduced in vivo) and in W256TK+ tumors but not in nontransduced wild-type W256 tumors. The level of "specific" incorporated radioactivity in transduced portions of both W256TK* and W256TK+ tumors was relatively constant between 4 and 50 h. In the second set, we tested whether [124I]-FIAU and PET imaging can measure and discriminate between different levels of HSV1-tk gene expression. Multiple s.c. tumors were produced from wild-type RG2 cells and stably transduced RG2TK cell lines that express different levels of HSV1-tk. A highly significant relationship between the level of [124I]-FIAU accumulation [% injected dose/g and incorporation constant (Ki)] and an independent measure of HSV1-tk expression (sensitivity of the transduced tumor cells to ganciclovir, IC50) was demonstrated, and the slope of this relationship was defined as a sensitivity index. We have demonstrated for the first time that highly specific noninvasive images of HSV1-tk expression in experimental animal tumors can be obtained using radiolabeled 2'-fluoro-nucleoside [124I]-FIAU and a clinical PET system. The ability to image the location (distribution) of gene expression and the level of expression over time provides new and useful information for monitoring clinical gene therapy protocols in the future.

Animals↗
PubMed1998

Tumor growth modulation by sense and antisense vascular endothelial growth factor gene expression: effects on angiogenesis, vascular permeability, blood volume, blood flow, fluorodeoxyglucose uptake, and proliferation of human melanoma intracerebral xenografts.

Vascular endothelial growth factor (VEGF), also known as vascular permeability factor, has been investigated as a potent mediator of brain tumor angiogenesis and tumor growth. We evaluated the effect of VEGF expression on the pathophysiology of tumor growth in the brain. Human SK-MEL-2 melanoma cells, with minimal VEGF expression, were stably transfected with either sense or antisense mouse VEGF cDNA and used to produce intracerebral xenografts. Vascular permeability, blood volume, blood flow, and tumor fluorodeoxyglucose metabolism were assessed using tissue sampling and quantitative autoradiography. Tumor proliferation was assessed by measuring bromodeoxyuridine labeling indices. Tumor vascular density and morphological status of the blood-brain barrier were evaluated by immunohistochemistry. SK-MEL-2 cells transfected with sense VEGF (V+) expressed large amounts of mouse and human VEGF protein; V+ cells formed well-vascularized, rapidly growing tumors with minimal tumor necrosis. V+ tumors had substantial and significant increases in blood volume, blood flow, vascular permeability, and fluorodeoxyglucose metabolism compared to wild-type and/or V- (antisense VEGF) tumors. VEGF antisense transfected V- expressed no detectable VEGF protein and formed minimally vascularized tumors. V- tumors had a very low initial growth rate with central necrosis; blood volume, blood flow, vascular permeability, and glucose metabolism levels were low compared to wild-type and V+ tumors. A substantial inhibition of intracerebral tumor growth, as well as a decrease in tumor vascularity, blood flow, and vascular permeability may be achieved by down-regulation of endogenous VEGF expression in tumor tissue. VEGF-targeted antiangiogenic gene therapy could be an effective component of a combined strategy to treat VEGF-producing brain tumors.

Animals↗
PubMed1998

Treatment of primary varicose veins: an assessment of the combination of high saphenous ligation and sclerotherapy.

This study was conducted to determine the optimal treatment for minimizing the recurrence of varicose veins, and to assess the value of the combined treatment of high saphenous ligation and sclerotherapy. A combined total of 967 limbs in 660 patients with primary varicose veins were treated. The treatments comprised: sclerotherapy alone in 81 limbs, high saphenous ligation alone in 3 limbs, a combination of sclerotherapy and high saphenous ligation in 843 limbs, and a combination of sclerotherapy and ligation of incompetent perforating veins in 10 limbs. Recurrent varicose veins appeared from 3 months after the initial treatment in 61 (6.3%) limbs. Saphenous-type recurrence, being the presence of saphenofemoral incompetence (SFI) and/or saphenopopliteal incompetence (SPI), was found in 20 limbs, and further treatment was given. Segmental-type recurrence, being superficial varices without SFI or SPI, was found in 41 limbs, all of which were treated with further sclerotherapy alone. To minimize the recurrence rate of varicose veins, the presence or absence of SFI, SPI, and incompetent perforating veins must be confirmed prior to the initial treatment. It was concluded that the combination of high saphenous ligation and sclerotherapy is effective for patients with SFI and/or SPI, whereas sclerotherapy alone is better for patients without SFI or SPI.

Adult↗
PubMed1998

Isolated right ventricular hypoplasia: intraoperative balloon occlusion test.

A 42-year-old woman with isolated right ventricular hypoplasia underwent operation. To determine the optimal procedure, we temporarily occluded the atrial septal defect with a balloon catheter that was introduced through the right atrial appendage. The hemodynamics were stable throughout the occlusion test. Simple closure of the atrial septal defect was safely accomplished. Intraoperative occlusion test with the balloon catheter was a good alternative to preoperative occlusion test.

Adult↗
PubMed1998

Effect of skeletonizing dissection on the internal thoracic artery.

BACKGROUND: Skeletonization of the internal thoracic artery (ITA) produces greater length for coronary bypass grafting. We studied the effect of skeletonization on the morphology, histology, and tissue viability of the ITA wall. METHODS: Six mongrel dogs underwent unilateral ITA dissection; the contralateral ITA was the control. Study periods were 3 weeks (n=3) and 12 weeks (n=3). At sacrifice, the entire anterior chest wall was removed and dynamically fixed with formalin. Extensive histologic comparisons were performed on three tissue blocks taken from each ITA, 2, 8, and 24 cm from their origin. RESULTS: Flows at the end of the study were comparable to measurements taken during operation, immediately after skeletonization. Grossly, the ITA wall was not injured by skeletonization and there was no adventitial hematoma or bleeding from the sealed branch ends. Microscopic observations showed intact, normal wall structures. Histologic data showed no major significant difference between controls and skeletonized ITAs. CONCLUSIONS: Careful skeletonizing dissection is not detrimental to the integrity of ITAs, which justifies their use for myocardial revascularization.

Animals↗
PubMed1998

Tube device for facilitating distal anastomosis in aortic arch replacement.

The technique of placing an inverted graft into the descending thoracic aorta facilitates and secures the distal anastomosis in aortic arch replacement, especially in the anastomosis beyond the transverse arch. We developed a simple technique using a pair of thin-walled tubes to enable the arch graft, with its four branches, to be smoothly inserted into the flaccid, normal-caliber descending aorta. The use of these tubes simplified the procedure, resulting in time saving.

Anastomosis, Surgical↗
PubMed1998

Role of medial smooth muscle cell function in antithrombogenicity of vein grafts.

OBJECTIVES: To determine the significance of prostaglandin I2 (PGI2) production by medial smooth muscle cells (SMCs), we assessed PGI2 production from denuded vein grafts and their antithrombogenicity. MATERIALS AND METHODS: A total of 30 dogs were divided into two groups: in group I, 14 dogs (27 veins, 188 segments) were used to assay PGI2 production, which was measured as 6-keto-PGF1 alpha. In group II, 16 dogs were used for an implantation study and the thrombus-free surface (TFS) score was calculated 24 h after implantation. Both groups contained the following subgroups: subgroup A, freshly harvested veins; subgroup B, endothelial denuded veins; subgroup C, veins frozen and cryopreserved; subgroup D, veins treated with protease. RESULTS: Values of 6-keto-PGF1 alpha (pg/mg/min) for basal and stimulated states in subgroup I-A through I-D were 58.0 +/- 8.9 and 530.6 +/- 74.7, 26.3 +/- 4.7 and 82.3 +/- 11.4, 17.9 +/- 1.3 and 39.4 +/- 3.3, and 13.3 +/- 1.8 and 32.2 +/- 6.2, respectively. The PGI2 production in subgroup I-A were significantly higher than those in the other three subgroups (p < 0.01 for basal and stimulated), while the production in subgroup I-B was also significantly higher than those in the remaining two (p < 0.05 for basal and stimulated). The TFS scores in subgroup II-A through II-D were 98 +/- 2%, 90 +/- 2%, 38 +/- 5%, and 15 +/- 7%, respectively, showing significantly superior antithrombogenicity in subgroup II-B, as well as in II-A, when compared with the remaining two (p = 0.014). CONCLUSION: The amount of PGI2 generated by the medial SMCs may be sufficient for maintaining the antithrombogenicity of the endothelial denuded AVGs.

Animals↗
PubMed1998

[Intraoperative coronary artery spasm treated by percutaneous cardiopulmonary support in a patient with left lung cancer].

A 53-year-old man with left lung cancer underwent left upper lobectomy and extended mediastinal lymphadenectomy. Shortly before the end of the operation, electrocardiogram showed elevation of ST wave and multiple ventricular premature contractures first, then ventricular fibrillations, and finally cardiac arrest. Coronary artery spasm was strongly suspected. The patient was resuscitated by cardiac massage and countershock immediately, however, such attacks repeated several times. As medication and cardiac pacing were not effective, percutaneous cardiopulmonary support (PCPS) was established. The hemodynamics was stabilized with PCPS. He was weaned off PCPS the next day. He was discharged and has had no attack so far. PCPS is an excellent modality for intraoperative coronary spasm which is uncontrollable by medicines and other methods.

Carcinoma, Squamous Cell↗
PubMed1997

Role of infrainguinal bypass in Buerger's disease: an eighteen-year experience.

OBJECTIVES: The role of bypass to the distal arteries for patients with Buerger's disease (thromboangiitis or TAO) remains controversial because of the high incidence of graft failure. We retrospectively reviewed the results of 71 bypasses to evaluate their efficacy. MATERIALS AND METHODS: We performed 71 autogenous vein bypasses in 61 patients with TAO. Of the patients, 97% were heavy smokers. The indications for surgery were claudication in 41%, and ischaemic ulcer or gangrene in 59%. Of the bypasses 85% were to the crural arteries or to the arteries below the ankle. The grafts used were 53 single saphenous veins, and 18 venovenous composite grafts. RESULTS: There were 38 graft failures, the main causes including anastomosis to a diseased artery, disease progression (which occurred in smokers after surgery), and vein graft stenosis. Of 38, 10 were restored to patency by revision surgery. Primary and secondary patency rates were 48.8% and 62.5% at 5 years, and 43.0% and 56.3% at 10 years, respectively. The patency rates of the postoperative non-smoking group was significantly higher than that of the smoking group (66.8% vs. 34.7%, p < 0.05). Thirty-six patients (59%) had successful revascularisation and returned to full-time work. However, of 28 with secondary failure, 11 underwent amputation, while 14 had persistent disabling claudication. CONCLUSION: Bypass to the distal arteries is an effective treatment for TAO patients, and the long-term patency is quite satisfactory as long as patients stop smoking.

Adult↗
PubMed1997

Intracarotid recombinant human tumor necrosis factor-alpha reduces cerebral blood flow and methionine uptake in rat brain tumors.

The aim of the present study is to understand the therapeutic effects of recombinant human tumor necrosis factor-alpha (rH-TNF) on hemocirculation and metabolism of brain tumors. Using double-label autoradiographic technique, we have monitored changes in regional cerebral blood flow (rCBF) and protein-bound fraction of (3H-methyl)-L-methionine, expressed as acid-insoluble fraction (AIF), in rat brain tumors following treatment with intracarotid rH-TNF. The central portion of tumors showed a significant decrease in rCBF and AIF at 4 hours after the injection (p < 0.01, p < 0.05, respectively, as compared with non-treated control rats), turned microscopically necrotic at 24 hours, and became more extensively necrotic at 72 hours. Tumor cells remained viable only in the peripheral portion of the tumors after the treatment. The peripheral portion also showed a moderate decrease in rCBF, but less change in AIF to 4 to 72 hours after the treatment. Neither ipsilateral nor contralateral non-involved cortex demonstrated appreciable changes in rCBF and AIF during the observed period. Intracarotid rH-TNF selectively reduces tumor rCBF and AIF, resulting in histological modification.

Animals↗
PubMed1997

Myristoyl gelatin as a sealant for Dacron vascular prostheses.

Myristoyl gelatin (MG) retains its gel structure at temperatures above body temperature without any crosslinking. As a coating material, MG adheres well to polyester fibers, and the outermost layers of the sealant that are in contact with blood or surrounding tissue become hydrophilic. We produced MG-impregnated knitted Dacron vascular prostheses (MG graft [MGG]) and investigated the usefulness of MG as a sealant by replacing the thoracic aorta of dogs. MGGs (5 cm long with an inner diameter of 10 mm) were implanted in 5 mongrel dogs (10-20 kg), and the grafts were retrieved at intervals of 4 h and 2, 4, 8, and 15 weeks after grafting. There was no thrombus formation on the flow surface of the MGGs, indicating adequate antithrombogenic properties. No resorption of MG occurred until after 2 weeks, and neither immune reaction nor excessive foreign body reaction was noted. Fragmentation of the sealant induced by cell infiltration began to occur at 4 weeks, yet the sealing effect persisted. The organization of MGG was almost complete at 8 weeks. Because of its pliability and effective adhesion to polyester fibers, its antithrombogenicity, and the persistent sealing effect due to delayed biodegradation and resorption, we conclude that MG is an extremely useful sealant for polyester vascular prostheses.

Animals↗
PubMed1997

Indications for differential diagnosis of nontumor central nervous system diseases from tumors. A positron emission tomography study.

To accurately differentiate nontumor central nervous system (CNS) diseases from brain tumors, we retrospectively evaluated the cerebral circulation and metabolism in patients with nontumor CNS diseases using positron emission tomography (PET). Regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extraction fraction (rOEF), the metabolic rates of oxygen (rCMRO2), and of glucose (rCMRGI), and the uptake of 11C-methyl-L-methionine (11C-Met) were visually evaluated in lesions and compared with values for the contralateral white matter regions. PET findings were correlated with those of x-ray computed tomography (CT) and magnetic resonance imaging (MRI), and were analyzed for nontumor CNS diseases and cerebral gliomas. rCBF and rCBV were changeable from disease to disease or from stage to stage of disease progression. rOEF and rCMRO2 remained low in 5 and 6, respectively, of 9 nontumor CNS diseases examined, whereas these parameters were increased in CNS infections such as brain abscess. Overall, noteworthy was the locally increased rOEF and rCMRO2 in the patients with a brain abscess in contrast to the values for patients with gliomas. rCMRGI reflected biological characteristics of each disease, and correlated with cell density, whether reactive glial cells or inflammatory cells. 11C-Met was accumulated at a certain stage of nontumor CNS diseases, which implied uptake of the tracer as a result of disruption of the blood-brain barrier as well as metabolic incorporation.

Adolescent↗
PubMed1997

[A case of ruptured aortic arch aneurysm with hemorrhagic cardiac tamponade].

The ruptured thoracic aortic aneurysm is still a dramatic even with very poor outcome, whereby its survival depends largely on early diagnosis and operation. We report a successful case of aortic arch replacement for ruptured aortic arch aneurysm with cardiac tamponade. Lethal hemopericardium causing cardiac tamponade is most commonly seen as a complication of acute myocardial infarction or acute aortic dissection, and subsequent rupture of the heart or ascending aorta leads to the rapid accumulation of blood within the poorly distensible pericardial sac. Our case was operated upon emergency basis due to hemopericardium. On operative findings, the aortic aneurysm located the minor curvature of aortic arch and was a huge saccular shape. In surgical procedure, the total arch replacement was completed using selective cerebral antegrade perfusion with deep hypothermia. Postoperative course was uneventful and no cerebral complication was observed after surgery.

Aortic Aneurysm, Thoracic↗
PubMed1997

Coronary artery bypass grafting of Takayasu's disease with calcified aorta and subclavian artery obstruction.

The lesions of Takayasu's disease, which may involve the aorta and major arterial branches, may pose technical difficulties during coronary artery bypass grafting (CABG). Because the aorta is often thick and calcified, the coronary arterial lesion is often located near the coronary orifice, and the internal thoracic arteries may not be suitable for grafting due to the lesions in the subclavian arteries. A 63-year-old man with a known history of Takayasu's disease was referred to our department with chest pain complaint. Coronary angiography revealed obstruction of the left main coronary artery. CT scan showed that he had a thickened and calcified aorta. Aortography showed that both subclavian arteries had obstructive disease. Instead of using ordinary arterial grafts or vein grafts, a piece of prosthetic patch carrying saphenous vein grafts was sewn to the ascending aorta to construct the proximal anastomosis of CABG. Distal anastomosis was made on the left anterior descending artery and the obtuse marginal branch in the usual fashion. The patient showed uneventful recovery, and a postoperative coronary angiogram showed patent grafts and uncomplicated ventricular performance. This technique is useful when the aorta is not suitable for vein graft anastomosis and arterial grafts are not available as in this case with aortitis reported in the paper.

Aorta↗
PubMed1997

[A study on low grade malignant tumors arisen in the trachea and the bronchus].

Twelve patients who suffered from low grade malignant tumors arisen in the trachea and the bronchus (6 of carcinoid, 4 of mucoepidermoid carcinoma, and 2 of adenoid cystic carcinoma) underwent surgical treatment from 1977 to 1996 in our department. Operations included 1 sleeve resection of the trachea, 1 patch plasty of the trachea, 3 sleeve lobectomies, and 7 lobectomies. Lymph node dissection was performed in 9 of 12 cases. Metastases in lymph nodes were not found in all 12 cases. Five year survival rate of low grade malignant tumors arisen in the trachea and the bronchus was 78.8% and better than that of stage I lung cancers.

Adolescent↗