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Biomedical subjects

T Akai

Publications and source records attributed to T Akai.

At least 19 recordsLinked to original sources
PubMed2002

Treatments of hamartoma with neuroendoscopic surgery and stereotactic radiosurgery: a case report.

Hypothalamic hamartoma is a non-neoplastic tumor manifesting as gelastic seizure, precocious puberty, and abnormal behavior. Treatment of it is very complicated due to its location. We report a case of hypothalamic hamartoma treated by neuroendoscopic surgery and stereotactic radiosurgery. A 5-year-old girl presented with violent behavior, precocious puberty, gelastic seizure and atonic seizure. She was diagnosed with hypothalamic hamartoma by CT and magnetic resonance imaging at 11 months of age. Tumor size did not change, but tumor intensity had changed on the MR image at 5 years of age. Magnetic resonance spectroscopy revealed decreased N-acetylaspartate and increased choline and creatine in the tumor. After neuroendoscopic biopsy, she underwent linear accelerator stereotactic radiosurgery. But her symptoms remained unchanged for 6 months. She then underwent partial resection and laser coagulation of the tumor by a neuroendoscopic approach. After the procedure, the frequency of her seizures was remarkably decreased, and her violent behavior improved. The transventricular neuroendoscopic approach to the hypothalamus is less invasive than the radical surgery. Neuroendoscopic surgery can be one of the treatments of choice for hypothalamic hamartoma.

Brain Diseases↗
PubMed2001

A silver-containing halogen-free inorganic photochromic glass.

A halogen-free inorganic photochromic soda-lime silicate glass containing silver ions has been developed; reversible change between colorless and yellow color in this glass is achieved through combined 193 nm excimer laser irradiation and heat treatment.

Journal Article↗
PubMed1999

Transformation of fibrolamellar carcinoma to common hepatocellular carcinoma in the recurrent lesions of the rectum and the residual liver: a case report.

A 21-year-old man had undergone central bisegmentectomy of the liver due to fibrolamellar carcinoma (FLC). Twice, 24 and 30 months after the first operation, lymph node metastases were removed. We have reported this case previously and this is the second report of the same case. Forty-two months after the second operation to remove lymph node metastases, a recurrence occurred in the rectum and was excised. However, the tumor also recurred in the residual liver. The patient underwent hepatectomy for a palliative purpose but died 16 months after the last operation. Histopathologically, the primary tumor was diagnosed as pure FLC, but the lymph node metastases had foci of the common hepatocellular carcinoma (HCC) mixed with FLC. In contrast, the recurrent tumors in the rectum and the residual liver showed the histopathological features of common HCC. Thus, during repeated recurrences, histopathological features changed from pure FLC to common HCC.

Adult↗
PubMed1999

Post-stroke treatment with imidapril reduces learning deficits with less formation of brain oedema in a stroke-prone substrain of spontaneously hypertensive rats.

The present study was undertaken to examine the effects of the ACE (angiotensin converting enzyme) inhibitor imidapril, on the brain, when administered after the onset of stroke in a stroke-prone substrain of spontaneously hypertensive rats (SHRSP). Learning deficits and induced lesions in the brain as well as in the kidneys and heart were investigated in detail. SHRSP were divided into two groups with or without salt loading at the age of 4 weeks. The salt loading was performed for 7-9 weeks to increase the incidence of stroke. Within 24 h after the first observation of stroke, animals were subsequently treated with 5 mg/kg imidapril orally once a day or the vehicle for up to the age of 27 weeks. Imidapril attenuated progression of neurological abnormalities such as irritability, hyperkinesia and motor dysfunction, and increased survival rate. In three-panel runway testing, learning deficits did not develop significantly in the imidapril-treated group, and was comparable to that in the non-salt-loaded/non-stroke group. Imidapril reduced oedema formation in the cortex, hippocampus and striatum, and also suppressed lesion formation in the kidneys and heart. Imidapril thus suppressed progression of neurological deficits with loss of learning ability following onset of stroke, and also suppressed formation of oedema in the brain and decreased the number of lesions in other organs. Imidapril-induced reduction of cerebrovascular damage, which presumably occurs in the brain after stroke, may account for the inhibitory effects of imidapril on lesion formation and learning impairment.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1999

Migrated disc in the lumbar spinal canal--case report.

A 49-year-old man who had complained of back pain for 20 years presented with numbness and pain in his left leg persisting for 6 weeks. Magnetic resonance imaging demonstrated a peripherally enhanced intraspinal mass at the L-3 level. The mass was completely removed. The operative and histological findings revealed degenerated disc fragments surrounded by granulation tissue. His symptoms were completely relieved. Migrated disc should be included in the differential diagnosis of patients with a long history of back pain and an intraspinal mass.

Diagnosis, Differential↗
PubMed1998

Treatment of chronic subdural hematoma by closed-system drainage without irrigation.

BACKGROUND: Recurrence of chronic subdural hematoma after surgery has not been eliminated. We sought to determine whether irrigation influences recurrence rate. METHODS: Patients who had undergone surgery for chronic subdural hematoma were reviewed retrospectively. RESULTS: Between 1986 and 1993, 186 cases of chronic subdural hematoma were treated surgically at Mito National Hospital. Recurrence was limited to six cases (3.2%). A closed drainage system without irrigation has been used since 1988 in 119 patients. Before 1988, 67 cases were treated with single burr hole irrigation and drainage. The rate of recurrence with the closed drainage system was 3.4% (four cases), compared with 3.0% (two cases) for irrigation and drainage. CONCLUSION: Compared with irrigation and drainage, the closed drainage system without irrigation was safe and effective, and recurrence of chronic subdural hematoma is not influenced by irrigation.

Adult↗
PubMed1998

Superior sagittal sinus thrombosis associated with primary antiphospholipid syndrome--case report.

A 36-year-old female with a history of recurrent pregnancy loss experienced sudden onset of disturbance in consciousness, with right hemiparesis and total aphasia. Computed tomography revealed a massive hemorrhage in the left frontal lobe, and angiography showed occlusion of the anterior two-thirds of the superior sagittal sinus. Laboratory investigations detected the presence of lupus anticoagulant, elevation of the anticardiolipin beta 2-glycoprotein I complex antibody level, and a decreased protein S activity level. There were no underlying conditions, such as connective tissue disorders, malignancies, infectious diseases, and drug-induced disorders, so the diagnosis was primary antiphospholipid syndrome. Primary antiphospholipid syndrome should be considered in the evaluation of patients with "idiopathic" or "primary" sinus and cerebral venous thrombosis.

Adult↗
PubMed1998

Pseudo-cerebrospinal fluid rhinorrhea after skull base surgery.

A 41-year-old female underwent complete resection of a left petroclival meningioma via an anterior transpetrosal approach, during which the greater superficial petrosal nerve was divided. On the 14th day after the operation, she first noticed leakage of clear fluid from her right nostril whenever the ambient room temperature rose. This pseudo-cerebrospinal fluid rhinorrhea may have developed because of parasympathetic hypersensitivity due to division of the greater superficial petrosal nerve.

Adult↗
PubMed1998

Nontraumatic convexity intradiploic arachnoid cyst.

A 63-year-old male presented with an unusual case of nontraumatic intradiploic arachnoid cyst in the frontotemporal convexity area. Skull radiography showed a circular osteolytic lesion of the right parietal bone. Computed tomography revealed a defect of the inner table, widened diploic space, and thinned outer table. Magnetic resonance imaging showed a cyst containing cerebrospinal fluid. Bone scintigraphy showed no abnormal uptakes. Intraoperative observation confirmed the neuroimaging findings. Histological examination found no abnormal findings in specimens of skull bone or arachnoid membrane. Intradiploic arachnoid cyst is characterized by parasagittal, multiple, well-demarcated osteolytic lesions on radiographs in the elderly. However, the clinical features of this disease remain unclear and diagnosis without an exploratory surgical procedure may not be possible.

Arachnoid↗
PubMed1998

Primitive neuroectodermal tumor in the spinal epidural space--case report.

A 4-year-old boy presented with a rare case of an epidural tumor causing compression of the thoracic spinal cord manifesting as rapid worsening of gait disturbance. The tumor was grossly totally resected, and radiotherapy and chemotherapy were subsequently administered. The histological diagnosis was primitive neuroectodermal tumor. He has been free of recurrence for more than 6 years. Early tumor resection followed by chemotherapy and irradiation is recommended for patients with primitive neuroectodermal tumor and unstable symptoms.

Chemotherapy, Adjuvant↗
PubMed1998

Extraneural metastasis of intracranial germinoma with syncytiotrophoblastic giant cells--case report.

A 14-year-old boy presented with an extraneural metastasis of germinoma with syncytiotrophoblastic giant cells (STGC). The tumor was located in the pineal area, suprasellar cistern, and frontal base, and associated with the slight elevation of the beta-human chorionic gonadotropin (HCG) serum level. Following radiation therapy, the tumor completely disappeared, and the beta-HCG level decreased to normal. Two years after the initial treatment, metastasis of the tumor to the left femur was observed without recurrence of the primary lesion. The biopsy specimen revealed germinoma, the diagnosis was germinoma with STGC because of the associated elevation of HCG level. The metastatic tumor was treated by chemotherapy with cisplatin and etoposide, and the tumor completely disappeared. With adjuvant chemotherapy, he has been recurrence-free for 3 years. Extraneural metastasis occurs more frequently from germinoma with STGC than germinoma. Aggressive chemotherapy combined with radiation therapy in the initial treatment might have to be tried to avoid metastasis from germinoma with STGC.

Adolescent↗
PubMed1997

Thrombin reduces large heparan sulfate proteoglycan molecules in cultured vascular endothelial cell layers through inhibition of core protein synthesis.

We investigated the alteration of heparan sulfate proteoglycans induced by thrombin in cultured vascular endothelial cells. Heparan sulfate proteoglycans, which were metabolically labeled with [3H] glucosamine and [35S] sulfate, were isolated by DEAE-Sephacel ion-exchange chromatography and characterized by molecular sieve gel filtration. Core proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of [35S] amino acids-labeled heparan sulfate proteoglycans after digestion with hepartinase. It was revealed that the high molecular weight subclass of heparan sulfate proteoglycans in the cell layer was markedly decreased by thrombin without changes of the hydrodynamic size of the molecules and the molecular weight of heparan sulfate chains. In addition, thrombin decreased the amount of large heparan sulfate proteoglycan core protein with a molecular weight of approximately 400 kDa, probably perlecan core, in the cell layer and the conditioned medium. The present data suggest that thrombin-induced decrease in the amount of heparan sulfate in vascular endothelial cell layer includes a reduction of the number of large heparan sulfate proteoglycan perlecan molecules through a suppression of the core protein synthesis.

Animals↗
PubMed1997

Leptomeningeal melanoma associated with straight sinus thrombosis--case report.

A 36-year-old female was admitted with leptomeningeal melanoma associated with straight sinus thrombosis manifesting as headache and vomiting. Computed tomography and magnetic resonance imaging showed the subarachnoid space was diffusely enhanced. Her consciousness rapidly deteriorated to a coma. Angiography demonstrated straight sinus thrombosis. Thrombolysis by superselective catheterization and infusion of urokinase was successfully performed. She recovered consciousness, but developed paraparesis 2 weeks later. Malignant melanoma with meningeal dissemination was diagnosed by an open biopsy of the lumbar lesion. Angiitis induced by the infiltration of tumor cells and activation of the blood coagulation cascade was probably the causative mechanism of the sinus thrombosis.

Adult↗
PubMed1997

[The outcome of cerebrovascular disease in the elderly].

The outcome of cerebrovascular disease in the elderly, defined as persons 70 years of age and over, and in the non-elderly, those under 70 years, was compared. Fifty-one consecutive elderly and 156 non-elderly patients were studied. The patients in each group were classified according to type of cerebrovascular event: intracerebral hemorrhage, cerebral infarction, or subarachnoid hemorrhage. Patients were evaluated by using the Glasgow Outcome Scale both at the time discharge and 6 months later. The elderly patients were more severely disabled at the time of discharge than the non-elderly patients. The number of patients evaluated as "good recovery" or "moderate disability" had increased at the 6-month follow-up examination in the non-elderly patients, whereas the condition of many of the elderly patients had declined. The death rate of the elderly at the time of discharge and 6 months later was 17.6% and 52.0%, respectively, as opposed to 13.5% and 18.8% in the non-elderly group. The outcome of cerebrovascular disease was much worse in the elderly patients than in the non-elderly patients. Patient age and status at discharge were important predictors of the clinical course.

Adult↗
PubMed1997

[Skull base aspergillosis granuloma originating from the sphenoid sinus: a case report].

A case of skull base Aspergillus granuloma originating from the sphenoid sinus was reported. This 64-year-old man complained of unilateral visual loss and serious facial pain, and was admitted to our department. He had been treated by transnasal sphenoidectomy because of sphenoid sinus aspergillosis. MRI showed a mass lesion located in the sphenoid sinus, cavernous sinus, ethmoid sinus and intraorbit. Angiography showed severe stenosis of the left internal carotid artery at the cavernous portion. As the symptoms gradually aggravated, we felt compelled to perform intracranial surgical treatment using the extradural approach to the skull base lesions. As the fibrous lesion was very hard and strongly adherent to the surrounding tissues, only partial removal of the lesion and resection of the trigeninal nerve were carried out. After surgery, the patient was released from severe facial pain and had an uneventful course. But, two months later, he died due to Aspergillus meningoencephalitis. Aspergillosis originating from the sphenoid sinus is rare, but it is known that some lesions show abrupt invasive extension to the skull base and the prognosis is bad. Early diagnosis and suitable treatment for the skull base or intracranial lesions is required.

Aspergillosis↗
PubMed1996

Intradiploic haemangioma associated with epidural haematoma.

A 72-year-old female with intradiploic haemangioma associated with epidural haematoma is reported. MRI finding of the lesion is described. The cause of the epidural haematoma is speculated due to fragile vessels attached directly to dura mater through the pores of the inner table of the diploë.

Aged↗