Biomedical subjects

T Isaka

Publications and source records attributed to T Isaka.

At least 19 recordsLinked to original sources

PubMed2006

[New forceps for a sutureless patch technique using sheet materials].

Intraoperative air leaks are often treated by a sutureless patch technique using a fibrin tissue-adhesive collagen fleece or synthetic materials with fibrin sealant. Intraoperatively, the technique of using these materials has been troublesome, therefore air leaks fail to close. Akicette has been applied as an easy sutureless patch technique for air leaks. Seven air leaks (5 were lung cancers, 2 were spontaneous pneumothorax) were treated with Akicette. Akicette is simple to operate with, and can easily carry sheet materials. Using Akicette, the sheet materials tightly adhered onto surrounding the pleural defect without any sliding on the wet lung surface. Akicette is feasible tool for a sutureless patch technique and is useful to easily place the sheet materials.

Biocompatible Materials↗

PubMed2004

[Clinical study on video-assisted thoracic surgical simultaneously stapled subsegmentectomy for peripheral lung tumors].

BACKGROUND: The purpose of this study is to confirm the safety and validity of video-assisted thoracic surgical simultaneously stapled subsegmentectomy (simultaneously stapling of all subsegmental bronchi and vessels in their natural construction). METHODS: The clinicopathologic information of the 10 patients who underwent video-assisted thoracic surgical simultaneously stapled subsegmentectomy for primary lung cancer (6) and metastatic lung tumor (4) were reviewed retrospectively. The patient population consisted of 7 men and 3 women with a mean age of 70.2 years. RESULTS: Median operative time was 201 minutes. Average blood loss was 76 ml. Mean duration of thoracic drainage was 3 days. There was no surgical mortality. Recurrence was diagnosed in 2 of 6 lung cancer patients (each of contralateral lung metastasis and brain metastasis), and 1 of 2 died 26 months after the operation. All patients have been followed for a mean period of 30.4 months with no local recurrence. CONCLUSIONS: Video-assisted thoracic surgical simultaneously stapled subsegmentectomy is safe and may be an acceptable alternative to segmentectomy, and wedge resection for strictly selective patients with peripheral lung tumors.

Adenocarcinoma↗

PubMed2004

[Inadvertent coil migration that required urgent thoracotomy during embolization for the treatment of pulmonary arteriovenous fistula].

A 70-year-old woman was referred to our department because of a solitary nodular shadow, 2 cm in diameter, in the right mid zone on a chest X-ray. Chest computed tomography revealed a pulmonary arteriovenous fistula (PAVF) in S4 of the right lung. Although the patient did not present with PAVF-related symptoms or hypoxemia, in view of the threat of serious complications, a therapeutic decision was made for coil embolization of the pulmonary artery feeding the PAVF. During the endovascular embolization procedure, the coil migrated into the mitral valve chordae tendinae. Urgent thoracotomy was therefore performed and the coil was safely retrieved from the site. Via the same thoracotomy incision, the PAVF with its surrounding tissue was also resected from the right lobe of the lung. The inadvertent coil migration in this patient may be explained by the fact that the fistula was not large enough to allow the coil to stay in place for the prevention of blood flow from the feeding vessel. These findings indicate that surgical resection of PAVF should be selected when the size of the fistula is too small for coil embolization. Otherwise, if transcatheter embolization is preferred, the detachable balloon approach may be appropriate.

Aged↗

PubMed2001

Intraoperative ultrasonographically guided direct ethanol injection for a brain metastasis from renal cell carcinoma: case report.

A 60-year-old man presented with a brain metastasis from renal cell carcinoma (RCC). Computer tomography revealed a homogeneously enhanced tumor, 3.0 cm in maximum diameter, in the right medial temporal lobe. Cerebral angiography revealed that the tumor was mainly fed by the right posterior cerebral artery. Surgery was performed via right temporal craniotomy. After craniotomy, under ultrasonography (US) guidance, a total of 3.0 ml of ethanol was injected into the tumor to diminish the intratumoral vascular flow. Ultrasonographic guidance was very useful in monitoring the intratumoral vascular flow. After a marked decrease in the vascular flow, the tumor was totally removed using piecemeal technique. During surgery, only minimal bleeding from the tumor was noted. The postoperative course was uneventful, with no evidence of injected ethanol-related complications. In conclusion, this can be a safe, easy, and effective therapeutic technique for diminishing vascular flow within brain tumors rich in vascularity, such as brain metastases from RCC.

Brain Neoplasms↗

PubMed2000

Ultrastructural changes of the vascular endothelium after intra-arterial administration of tumor necrosis factor-alpha (TNFalpha) in rat gliomas.

The ensuing ultrastructural changes in tumor vascular endothelial cells following intra-arterial administration of tumor necrosis factor-alpha (TNFalpha) were studied in an experimental rat glioma model. C6 glioma cells were implanted in Wistar rats and then after 14 days, 5 x 10(3) U of human natural-type TNFalpha (1.7 x 10(5) U/m2) was administered through the carotid artery. The animals were sacrificed at 3 or 24 h after TNFalpha treatment. A detailed examination with transmission electron microscope revealed swelling of the tumor vascular endothelial cell nuclei and mitochondria with matrix densities at 3 h. At 24 h, these cells demonstrated the presence of high amplitude mitochondrial swelling or the violent blebbing characteristic of damaged mitochondria; the cytoplasm was swollen enormously and there were dissolution of cytoplasmic organelles and rupture of the plasma membrane. The observed findings were typical of cell necrosis and confirms yet another mechanism by which TNFalpha exerts its anti-tumor effects, that is, necrotizing effects on tumor vascular endothelium. The information appears to be important in the context of clinical application of intra-arterial TNFalpha in the treatment of malignant gliomas.

Animals↗

PubMed2000

Successful removal of a giant skull base metastasis from hepatocellular carcinoma after direct ethanol injection: case report.

Skull metastases from hepatocellular carcinoma (HCC) are extremely rich in vascularity, which sometimes makes surgery dangerous. For minimally invasive surgery, it is very important to diminish the intratumoral vascular flow preoperatively. We report the case of a 69-year-old man with a giant skull base metastasis from HCC that was successfully removed after two sessions of direct ethanol injection into the tumor as a preoperative treatment to diminish the intratumoral vascular flow. Direct ethanol injection is a modification of percutaneous ethanol injection therapy, which is widely used in the treatment of primary HCC. In this article, we describe in detail the practical procedures and the usefulness of this treatment for a giant skull base metastasis from HCC.

Case Reports↗

PubMed2000

Effectiveness of spray application of ACNU in the local control of malignant gliomas: report of two cases.

Malignant gliomas encompassing the eloquent areas cannot be removed totally and their surgical extirpation is followed by adjuvant therapy for the residual tumor. Recently, we have employed fibrin glue as a vehicle for the sustained release of ACNU (nimustine hydrochloride) by spray application following subtotal tumor removal in two patients with recurrent malignant gliomas. Follow-up MRI at six months demonstrated no neuroradiological evidence of tumor recurrence in the site of operation. We conclude, this novel mode of intra-operative local chemotherapy by spray application of fibrin glue containing antineoplastic agent is effective in the control of residual tumor progression and may also prevent local recurrence and hence suggests its possible role as an adjuvant therapy in the management of malignant gliomas.

Aerosols↗

PubMed1999

Hemangioblastoma of the third ventricle.

A third ventricle tumor, in addition to a recurrent cerebellar hemangioblastoma, was found in a 47-year-old woman on follow-up magnetic resonance imaging (MRI) 5 years after operation of the cerebellar tumor. On MRI, the tumor was hypo- to isointense on T1-weighted images and hyperintense on T2-weighted images compared with the normal gray matter, and was strongly enhanced with gadolinium. The tumor was first treated with fractionated conventional external-beam radiation (5120 cGy in 16 fractions over a 4-week period), resulting in a slight decrease in size of the tumor. For a definite diagnosis and mass reduction, surgery was performed using an interhemispheric translamina terminalis approach, resulting in a partial removal of the tumor due to profuse bleeding. Histological diagnosis was hemangioblastoma. Hemangioblastomas of the third ventricle are extremely rare and have not been specifically discussed. We describe the detailed clinicopathological features of the present case together with the possible explanation for the development of this tumor in this rare location.

Cerebellar Neoplasms↗

PubMed1998

A new in-vitro drug sensitivity test (collagen-gel droplet embedded-culture drug sensitivity test) in carcinomas of pancreas and biliary tract: possible clinical utility.

The collagen-gel droplet embedded-culture drug sensitivity test (CD-DST), a chemosensitivity test, evaluate the efficacy of anticancer drugs and to was used clinically to thus plan rational postoperative chemotherapy for patients with pancreatic and biliary tract carcinomas. The CD-DST solves some problems inherent in other conventional assays. This method: (1) allows evaluation of four chemotherapeutic agents, using small quantities of cells (1 x 10(5) cells), (2) shows high primary culture success rates, (3) maintains the original growth characteristics of the cultured cells, (4) eliminates the effects of fibroblasts by employing image analysis, and (5) permits evaluation using physiologic drug concentrations. Primary cultures of tumor cell samples from all 25 patients with pancreatic or biliary tract carcinomas studied were successful. Against pancreatic carcinomas, the efficacy rates, assessed by CD-DST, of four anticancer drugs evaluated were: 25.0% for mitomycin (MMC), followed by 23.5% for adriamycin, 18.8% for 5-fluorouracil (5-FU), and 11.8% for cisplatin (CDDP). Against biliary tract carcinomas, the rates were highest for 5-FU and MMC (50.0%) and lowest for CDDP (25.0%). The efficacy rates for all four anticancer drugs evaluated were higher against biliary tract carcinomas than against pancreatic carcinomas. Tumor cultures from 10 of 17 patients with pancreatic cancer and 3 of 8 patients with biliary tract cancer showed no sensitivity to any of the drugs tested. The in-vitro results with CD-DST suggest the risk of administering non-selective postoperative chemotherapy to patients with pancreatic and biliary tract carcinomas, and emphasize the importance of carefully selecting effective chemotherapeutic agents based on adequate chemosensitivity testing.

Antineoplastic Agents↗

PubMed1998

Is coordination of two-joint leg muscles during load lifting consistent with the strategy of minimum fatigue?

The purpose of this study was to examine if strong correlations reported for a back lift task between activity (EMG) of two-joint rectus femoris (RF), hamstrings (HA), and gastrocnemius (GA) and the difference in the joint moments could be predicted by minimizing an objective function of minimum fatigue. Four subjects lifted barbell weights (9 and 18 kg) using a back lift technique at three speeds normal, slow, and fast. Recorded ground reaction forces and coordinates of the leg joints were used to calculate the resultant joint moments. Surface EMG of five muscles crossing the knee joint were also recorded. Forces of nine muscles were calculated using static optimization and a minimum fatigue criterion. Relationships (i) (RF EMG-HA EMG) vs (knee moment hip moment) and (ii) GA EMG vs. (ankle moment knee moment) were closely related (coefficients of determination were typically 0.9 and higher). Qualitatively similar relationships were predicted by minimizing fatigue. Gastrocnemius and hamstrings had the agonistic action at both joints they cross during load lifting, and their activation and predicted forces increased with increasing flexion knee moments and extension ankle and hip moments. The rectus femoris typically had the antagonistic action at the knee and hip, and its activation and predicted force were low. Patterns of predicted muscle forces were qualitatively similar to the corresponding EMG envelopes (except in phases of low joint moments where accuracy of determining joint moments was presumably poor). It was suggested that muscle coordination in load lifting is consistent with the strategy of minimum muscle fatigue.

Ankle Joint↗

PubMed1998

Direct ethanol injection for skull metastasis from hepatocellular carcinoma. The techniques and consequences of a therapeutic trial.

The frequency of skull metastasis from hepatocellular carcinoma (HCC) is increasing together with the recent progress in the management of the primary lesion. Cases are often complicated with poor general conditions or metastasis to the other organs, and not readily indicated for surgery. A direct injection of ethanol to the lesion could be one of the therapeutic options to cope with this complicated situation. To evaluate the feasibility of this technique, we planned a therapeutic trial in a patient with HCC associated with lumbar and skull metastasis, the latter metastasis repeated twice during the past one year. A total of 10 ml of ethanol was injected into the skull metastasis percutaneously under ultrasound (US) guidance. US guidance was very useful in determining the sites of injections and the distribution of ethanol as well as monitoring the blood flow within the tumor vessels. The patient transiently complained of local pain at the injection sites, but there were no other adverse effects. Four days after the injection, the lesion was resected by surgery, which confirmed the pathologic diagnosis as well as the nearly-total necrosis of the tumor. This technique is simple, safe and repeatable with low cost. The technical details and the histologic effects are described.

Aged↗

PubMed1996

Cellular targets of exogenous tumour necrosis factor-alpha (TNF alpha) in human gliomas.

To identify the cellular targets of TNF alpha in human gliomas, a total of 30 surgical specimens (12 glioblastomas, 4 anaplastic astrocytomas, 3 astrocytomas, 7 brains adjacent to tumour (BAT), 4 histologically normal-appearing brains) were examined by in vitro binding technique using biotinylated TNF alpha. The TNF-binding sites (TNF-BS) were recognized in the tumour cells in 8 of the 12 glioblastomas, 3 of the 4 anaplastic astrocytomas and in all the 3 astrocytomas. The TNF-BS were also recognized in the vascular endothelial cells in all these cases. The presence of TNF-BS in blood vessels ranged from 7.7 to 74.4% of the background vessels. This wide range of variation in the presence of TNF-BS within the tumour cells and tumour blood vessels may be relevant to the variable response of individual tumours to TNF alpha therapy. Since the tissue of normal brain, which lacks TNF-BS, might hardly be affected by this cytokine, administration of TNF alpha may be considered as an adjuvant therapy in selected groups of patients.

Binding Sites↗

PubMed1996

Morphological effects of tumor necrosis factor-alpha on the blood vessels in rat experimental brain tumors.

The morphological changes in the vascular endothelium caused by the administration of tumor necrosis factor-alpha (TNF-alpha) were studied in an experimental model of rat brain tumors. Wistar rats bearing implanted C6 glioma received human natural-type TNF-alpha (1.7 x 10(5) U/m2) through the carotid artery and were sacrificed 3 or 24 hours later. The endothelial cells of the tumor blood vessels, demonstrated by the immunoreaction to factor VIII-related antigen, were enlarged after TNF-alpha administration. Morphometry demonstrated that the nuclei of these endothelial cells were also increased in size. The endothelial cells in the brain remote to the tumor were not affected. An in vitro binding study demonstrated that TNF-alpha binding sites were distributed in the vascular endothelial cells within the tumor but not in the brain remote to the tumor. The selective effect of TNF-alpha on the tumor blood vessels in experimental brain tumors may be related to the selective distribution of the TNF-alpha binding site.

Animals↗

PubMed1996

Asymptomatic hypothalamic hamartoma associated with an arachnoid cyst--case report.

A 42-year-old male presented with the complaint of mild left facial numbness. Magnetic resonance imaging demonstrated a solid tumor in the interpeduncular cistern and a huge arachnoid cyst in the left middle cranial fossa. The tumor appeared isointense to the surrounding cerebral gray matter on T1-weighted images and hyperintense to that on T2-weighted images. The tumor was partially resected. Histological findings were characteristic of hamartoma. The mild left facial numbness was probably due to compression of the left trigeminal nerve by the arachnoid cyst. Asymptomatic hypothalamic hamartomas may occur in adults with atypical clinical presentations.

Adult↗

PubMed1995

Cell counts in peripheral blood and bone marrow of male C.B-17 scid/scid mice.

Blood cell and bone marrow cell counts were carried out for male C.B-17 scid/scid (SCID) mice aged 3, 6, 9, 18 and 26 weeks and the values were compared with those in C.B-17 +/+ (C.B-17) mice. In the peripheral blood, SCID mice had markedly low numbers of leucocytes and lymphocytes throughout the study. In the bone marrow, SCID mice had relatively low levels of erythroblasts at an early age, low levels of lymphocytes and plasma cells were absent.

Animals↗

PubMed1994

Altered expression of antithrombotic molecules in human glioma vessels.

A total of 14 surgical specimens, including 7 glioblastomas, 3 anaplastic astrocytomas, 2 brains adjacent to glioblastoma and 2 grossly normal brains, were investigated immunohistochemically for the expression of antithrombin III (AT-III), heparan sulfate proteoglycan (HSPG) and thrombomodulin (TM) in the endothelium of microvessels. The immunoreaction to AT-III was of moderate intensity in grossly normal brains, brains adjacent to glioblastoma, and anaplastic astrocytomas, but was only weak in glioblastomas, especially in the capillaries. The immunoreaction to HSPG was constantly intense in the microvessels in all the specimens. Although the immunoreaction to TM was negative or only faint in the microvessels in grossly normal brains, it was moderately to strongly intense in anaplastic astrocytomas and brains adjacent to glioblastoma. The intensity of immunoreaction to TM was variable, from faint to strong in the capillaries, and moderate to strong in larger microvessels in glioblastomas. The present study suggested that the alterations in the expression of those antithrombotic molecules could explain, at least in part, the tendencies for intratumoral hemorrhage as well as intravascular thrombosis in the different areas of malignant gliomas.

Antithrombin III↗

PubMed1994

Expression of thrombomodulin in astrocytomas of various malignancy and in gliotic and normal brains.

A total of 22 surgical specimens, 16 astrocytomas with various malignancy, 3 brains adjacent to tumor and 3 brains with non-neoplastic lesion, was investigated immunohistochemically for the expression of thrombomodulin (TM). This membrane protein is localized on the vascular endothelium of nearly every human tissue and plays a crucial role in the maintenance of antithrombotic property of the endothelial cells. Although the normal cerebral vessels were negative for TM, the tumor vessels were positive for TM. The increased expression of TM was, however, demonstrated not only in glioblastomas but also in low-grade astrocytomas. Furthermore, the vessels in the brains adjacent to tumor and gliotic brains were also positive for TM. Those observations suggested that the tendency of intratumoral bleeding, which is rather characteristic of glioblastomas, is not simply explained by the altered expression of vascular endothelial TM. In two cases of glioblastoma, not only the blood vessels but also the tumor cells were positive. Considering the mitogenic activity of thrombin, a ligand for TM, the increased expression of TM might be related to the tumor neovascularization and also the tumor growth.

Astrocytoma↗

PubMed1994

Remote subarachnoid haemorrhage in the posterior fossa following supratentorial surgery. Clinical observation of 6 cases.

Haemorrhage in regions remote from the site of following intracranial operations is rare, but they do occur. We performed supratentorial craniotomy on 639 patients between the time of introduction of computed tomography (CT) for clinical use in 1983 and June 1992; subarachnoid haemorrhage (SAH) in the posterior fossa occurred postoperatively in six of these cases. These included four patients with tumours in the sellar region, one with an arteriovenous malformation (AVM) and one who underwent superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis. The ages of the six patients ranged from 17-72 years. Haemorrhage occurred on the day of operation in one case and was detected on CT examination on the day following surgery in the remaining five cases. Of three patients with disturbance of consciousness, two underwent suboccipital craniectomy for reduction of intracranial pressure, while one received barbiturate therapy and later underwent cerebrospinal fluid (CSF) shunt surgery. No special treatment was necessary for the remaining three patients with less serious lesions. Five of the six patients ultimately recovered their pre-operative neurological status apart from the primary diseases. Factors inducing such haemorrhages seem likely to include displacement of the cerebellum by reduced CSF pressure during and after operations, and stretching and tearing of the veins and venules in the sulci of the tentorial surface of the cerebellum. Consideration should therefore be given to the maintenance of an appropriate CSF pressure during operation; this is particularly important in elderly patients and those with an atrophied cerebral cortex.

Adolescent↗