Biomedical subjects
Publications and source records attributed to T Maehara.
We report a case of the papillonodular type of cystic partially differentiated nephroblastoma (CPDN), an extremely rare renal neoplasm that occurs in newborns and infants. The papillonodular type of CPDN is a variant of the conventional form of CPDN. MRI clearly demonstrated the gross pathologic features, distinguishing it from other renal multilocular cystic tumors.
Placenta play the important role of nourishment of fetus and for the regulation of fetal and maternal steroid metabolism. Steroid metabolism is synthesized in mitochondria and levels of enzymes in steroid metabolism are regulated by the rate of synthesis and degradation of these enzymes. Therefore, we studied protease in human placental mitochondria to clarify regulation mechanism of steroid-synthesizing enzymes. 50 micrograms of human early and term placenta homogenate, proteins were analyzed by immunoblotting technique after SDS-polyacrylamid gel electrophoresis. ATP-dependent protease was detected using antiserum raised against purified bovine adrenocortical ATP-dependent protease and avidin-biotin complex method. ATP-dependent protease activity was assayed using 14C-Caseins a substrate. Five cell fractions of homogenate placenta were electrophorated and antibody-stained using ATP-dependent protease, cytochrome P-450 scc and adrenodoxin antibody after the blotting, and the quantity was analyzed by the densitometry and the method of De Douve. We had the following results: 1) ATP dependent protease is present in human placenta and localized in mitochondria. 2) ATP dependent protease decomposes adrenodoxin reductase in human placenta. 3) ATP dependent protease present in almost same consistent in early and term placenta and there is no significant difference. It is suggested as follows that the ATP dependent protease in human placenta participates in the regulation of steroid hormone through the metabolism of steroid synthetic enzyme.
Brain tumors with secondary ipsilateral cerebral hemiatrophy are so rare that only seven cases have been reported in the literature. Three new cases are presented and the clinical findings in all 10 cases are reviewed. The diagnostic value of computed tomography (CT) is emphasized. The authors conclude that nodular high-density lesions located deep in the cerebrum and showing slight contrast enhancement on CT may be associated with ipsilateral cerebral hemiatrophy in young male patients with slowly progressive hemiparesis, dementia, and personality change. In such cases, early diagnosis of germinoma and subsequent radiotherapy may prevent unnecessary surgery.
The authors present a case of hypertensive encephalopathy in which CT and MR were performed. The brain stem and cerebellum were revealed as low density areas on CT and high intensity areas on T2-weighted MR images with mass effect. Slight abnormality was also noticed in the deep cerebral white matter. This distribution pattern is contrary to that described in previous reports in which cerebral white matter was mainly involved. The lesions showed definite improvement when the blood pressure was normalized. MR is more sensitive than CT, and is useful for early detection of the abnormality and follow-up study.
A 31-year-old female having a family history of neurofibromatosis 1 presented a left CPA tumor. MRI findings showed a completely extraaxial tumor, suggesting an acoustic neurinoma except for the lesion in the acoustic meatus. However, the final diagnosis was of exophytic pontine glioma. When a CPA tumor shows no lesion in the internal acoustic meatus, the possibility of exophytic pontine glioma should be considered in the differential diagnosis, especially in NF-1 patients.
This paper reports a patient with advanced esophageal cancer who has survived asymptomatically for five years after radiotherapy given under informed consent. Previously, we had not practiced radiotherapy under informed consent for patients with esophageal cancers. His excellent clinical course encouraged us to promote this form of treatment. This report presents his excellent clinical course in detail and discusses the significance of informed consent in radiotherapy for malignancies.
Since the introduction of linac radiosurgery in October 1994, we have treated 27 patients with 36 lesions. We treated nine AVM, 12 metastatic brain tumors, two malignant lymphomas, one anaplastic astrocytoma, two meningiomas, and one brain tumor of unknown pathology. In the follow-up examinations at least five months after treatment, the local control rate was 83% for the metastatic tumors, and two malignant lymphomas disappeared completely. In addition, satisfactory results have been obtained with AVM and other brain tumors without any side effects. In comparison with gamma-knife radiosurgery, linac radiosurgery has some disadvantages such as longer treatment time and cumbersome accuracy control, but if accuracy control is performed periodically, accuracies of 1 mm or less can be obtained. There is some strengths of linac radiosurgery as follow. 1) The acquisition cost is relatively low. 2) Dose distribution are equivalent to gamma-knife. 3) There is no field size limitation. 4) There is great flexibility in beam delivery and linac systems. Radiosurgery using linear accelerators seems to become widely accepted in the future.
We report a case of linear nevus sebaceous syndrome with seizure, mental retardation, and hemiparesis. Magnetic resonance imaging (MRI) clearly demonstrated associated brain malformations of unilateral megalencephaly with cortical dysplasia and white matter change ipsilateral to the sebaceous nevi of the face and neck. Although magnetic resonance angiography (MRA) demonstrated only distortion of the main cerebral arteries without any occlusive or dysplastic findings, single photon emission computed tomography (SPECT) using [123I]N-Isopropyl-p-iodoamphetamine (IMP) revealed hypoperfusion in the affected cerebral hemisphere.
Multiple malignant gliomas are relatively uncommon, but are sometimes difficult to differentiate from multiple metastatic brain tumors. We analyzed the MR findings of four cases of multiple gliomas, comparing them with 12 cases of multiple metastatic brain tumors. All tumors were pathologically proven by surgical operation or autopsy. Gliomas were located in the deep white matter of the cerebrum, with none found in the posterior fossa. Tumors were relatively large, and irregular, thick, ring-like enhancement was noted after the administration of Gd-DTPA. Intratumoral hemorrhage was noted in only one case. High signal intensity on T2WI around the tumor suggested that edema was greater and more extensive than in metastatic tumors and was seen even in the corpus callosum. One autopsied case that showed this high intensity presented not only edema but also tumor infiltration. Metastatic tumors were located mainly in the corticomedullary junction of the brain. They were relatively small, and eight of 12 tumors showed, nodular or smooth ring-like enhancement. Intratumoral hemorrhage was noted in four cases. Edema was noted mainly around the tumor. We conclude that differential diagnosis between gliomas and metastases is possible to some extent by MRI.
We studied 76 patients with cerebral arteriovenous malformations (AVMs) using dynamic-CT with intravenous injection of contrast material and reconstructed three-dimensional images (3D-CT angiography). All patients received stereotactic radiotherapy (gamma-knife). We compared 3D-CT angiography with conventional angiography to determine the usefulness of this technique. 3D-CT angiography could be performed in conjunction with usual axial high-resolution CT without any additional scanning time and within 10-30 minutes for the overall study. Most niduses and drainers of AVMs were clearly visualized by 3D-CT angiography. 3D-reconstruction was very helpful in demonstrating the niduses, drainers, and three-dimensional structure of AVMs. Demonstrations of feeders were not remarkable. Dynamic CT was very helpful in dose planning for gamma-knife radiosurgery, because gamma-knife angiograms were limited in terms of angles, magnification, and establishing precise localizations using a head frame. 3D-CT added information on trails of drainers and was useful in reducing the volume of irradiation. 3D-CT angiography of cerebral AVMs could be performed routinely, and three-dimensional imaging was helpful in demonstrating the complex anatomy of cerebral AVMs. This technique was very helpful in planning gamma-knife radiosurgery.