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Biomedical subjects

Y Nakasu

Publications and source records attributed to Y Nakasu.

65 records · Page 4Linked to original sources
PubMed1982

Conservative management of congenital defect of skull and scalp.

A case of congenital defect of the scalp and skull, treated conservatively with success, is reported. The defect of the scalp healed rapidly and the underlying osseous defect closed within eight months. The course of obliteration of the osseous defect was followed using radiological methods.

Bone Diseases↗
PubMed1981

Computed tomography of intracranial epidermoid tumours with special reference to atypical features.

Intracranial intradural epidermoid tumours have been known to show characteristic CT features consisting of non-enhancing lucent lesions with sharply defined margins that are often irregular and scalloped. Since the epidermoid tumours are benign, potentially curable lesions, it should be also noted that they may occasionally show atypical CT features such as dense lesion, definite marginal enhancement following contrast medium injection, or tumour associated with large, heavy calcifications. Four such atypical cases are reported, and the literature is reviewed.

Adult↗
PubMed1981

[Giant neurofibroma of the occipital scalp associated with lambda defect-case report (author's transl)].

Calvarial bone defect associated with a hugh neurofibroma in the region of the lambdoid suture was reported in a 42-year-old man with v. Recklinghausen's neurofibromatosis. An enlarging occipital tumor was first noted at age 4 similar to or approximately 5, and an operation was performed at age 12. Lambda defect was noted at that time, but the operative diagnosis was, apparently, "meningocele". Available literature was reviewed, and the significance of calvarial bone defect in the region of the lambdoid suture as a manifestation of v. Recklinghausen's disease was stressed. Lambda defect witn no sclerosing margin, particularly if associated with hypoplasia of the ipsilateral mastoid cells, has been known to represent the primary nature of the bone defect due to mesodermal dysplasia. In the present case, plain radiographs of the skull revealed abnormal sclerotic change around the bone defect. It is suggested that such an osteoblastic change may well indicate the secondary nature of the bone defect due to the presence of overlying neurogenic tumor.

Adult↗
PubMed1980

Amenorrhea-galactorrhea syndrome with craniopharyngioma.

Two cases of craniopharyngioma presenting with amenorrhea-galactorrhea syndrome due to hyperprolactinemia are reported. After operation and irradiation, the tumor reduced markedly in size. Coincidental decrease in plasma prolactin level and restoration of menstruation seem to support the view that the hypothalamic prolactin inhibiting factor (PIF) had played an important role in hyperprolactinemia in these two patients.

Adult↗
PubMedDate not supplied

Sequential MRI findings in a patient with a germ cell tumor in the basal ganglia.

Serial changes of MRI scanning of an 11-year-old boy with hemiparesis due to a germ cell tumor in the basal ganglia are presented. Initial brain MRI T1-weighted images revealed a subtle mixed signal intensity lesion at left anterior and posterior limbs of the internal capsule. This lesion was not enhanced with Gd-DTPA, however, T2-weighted images showed a misty high signal intensity lesion in the same region. The MR images also showed hemiatrophy of the left basal ganglia. Histologic examination of biopsy specimens of the tumor revealed an embryonal carcinoma. The patient was treated with chemotherapy with subsequent improvement in the hemiparesis. Our case suggests that germ cell tumors must be considered in the differential disorders of lesions in the ipsilateral hemiatrophic basal ganglia in pediatric patients with hemiparesis.

Basal Ganglia↗
PubMedDate not supplied

Diffusion-weighted MR in experimental sustained seizures elicited with kainic acid.

PURPOSE: To investigate the early changes in diffusion-weighted MR images in the sustained limbic seizures. METHOD: Intraperitoneal injection of kainic acid was used to induce sustained limbic seizures in seven rats. The animals were investigated with serial 2.0-T MR imaging beginning immediately after kainic acid-induced seizures, and at 24 hours, 3 days, and 7 days after the kainic acid injection. Diffusion-weighted spin-echo and T2-weighted images and apparent diffusion coefficients were sequentially assessed and compared with histologic changes. The results were compared with eight control animals given buffered saline intraperitoneally. RESULTS: Diffusion-weighted MR images revealed an increase in signal intensity bilaterally in the amygdala and the piriform cortices immediately after the sustained seizures, whereas T2-weighted images did not show changes in signal intensity at this time. Both diffusion-weighted and T2-weighted images showed marked increase in signal intensities in these same areas 24 hours after kainic acid injection. The apparent diffusion coefficient values were significantly lower in the area of the amygdala and the piriform cortex immediately after and lower again 24 hours after the sustained seizures. The area of hyperintensity in diffusion-weighted images was concordant with the histologic distribution of neuronal pyknosis and neuropile vacuolation. CONCLUSION: Diffusion-weighted MR revealed focal abnormalities in the limbic system after 1 hour of sustained seizures induced with kainic acid, before changes on T2-weighted imaging. Diffusion-weighted MR is a potential method for studying the mechanisms of brain damage caused by sustained seizures.

Amygdala↗