Heitaro Mogami

Chemotherapy of brain metastases from lung carcinoma: a controlled randomized study.

A controlled randomized study was carried out to evaluate the effects of chemotherapy in patients with brain metastases from lung carcinoma. One hundred patients were randomly divided into three groups at the time of diagnosis or after surgery for metastases. Group A received radiotherapy alone; Group B received radiotherapy and chloroethylnitrosoureas (methyl-CCNU, 100-120 mg/m2, or ACNU 80-100 mg/m2, every 6-8 weeks), and Group C received radiotherapy and a combination of chloroethylnitrosoureas and tegafur (300 mg/m2, daily). Of the 100 patients, 88 could be evaluated. The reduction rates of the tumors of the patients in whom tumor was not surgically removed or not totally removed were compared. Complete resolution of the tumor was noted in 29, 69, and 63% of the patients in Groups A, B, and C, respectively. Tumor regression of greater than or equal to 50% was seen in 36, 69, and 74% of the patients in Groups A, B, and C, respectively. The difference in the response rates of Groups A and C was statistically significant (P less than 0.05). Median survival after the start of treatment for brain metastasis was 27, 30.5, and 29 weeks in Groups A, B and C, respectively. There was 1 long-term survivor (more than 5 years) in Group A, 3 in Group B, and 1 in Group C. The main cause of death was deterioration attributable to the primary lesion or systemic metastasis, and no statistical difference was noted in survival time among the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuronal network disturbance after focal ischemia in rats

We studied functional disturbances following left middle cerebral artery occlusion in rats. Neuronal function was evaluated by [14C]2-deoxyglucose autoradiography 1 day after occlusion. We analyzed the mechanisms of change in glucose utilization outside the infarct using Fink-Heimer silver impregnation, axonal transport of wheat germ agglutinin-conjugated-horseradish peroxidase, and succinate dehydrogenase histochemistry. One day after occlusion, glucose utilization was remarkably reduced in the areas surrounding the infarct. There were many silver grains indicating degeneration of the synaptic terminals in the cortical areas surrounding the infarct and the ipsilateral cingulate cortex. Moreover, in the left thalamus where the left middle cerebral artery supplied no blood, glucose utilization significantly decreased compared with sham-operated rats. In the left thalamus, massive silver staining of degenerated synaptic terminals and decreases in succinate dehydrogenase activity were observed 4 and 5 days after occlusion. The absence of succinate dehydrogenase staining may reflect early changes in retrograde degeneration of thalamic neurons after ischemic injury of the thalamocortical pathway. Terminal degeneration even affected areas remote from the infarct: there were silver grains in the contralateral hemisphere transcallosally connected to the infarct and in the ipsilateral substantia nigra. Axonal transport study showed disruption of the corticospinal tract by subcortical ischemia; the transcallosal pathways in the cortex surrounding the infarct were preserved. The relation between neural function and the neuronal network in the area surrounding the focal cerebral infarct is discussed with regard to ischemic penumbra and diaschisis.

Ultrastructural investigation of the CA1 region of the hippocampus after transient cerebral ischemia in gerbils

SummaryUltrastructural damage leading to delayed neuronal death was investigated in the mid-CA1 region of the hippocampus from the stratum (str.) moleculare to oriens after transient bilateral forebrain ischemia in Mongolian gerbils. After ischemia for 5 min without recirculation, mild swelling of the peripheral part of the apical and basal dendrites was already apparent in the str. moleculare and str. oriens. Mitochondria in the dendrites were also swollen in the same area. During recirculation for 12 h to 3 days, swelling of the dendritic cytoplasm persisted with formation of microvacuoles, but swelling of mitochondria receded. Microvacuolation and loss of microtubules were also observed in the proximal part of the dendrites during this period, and swelling and disruption of internal cristae were observed in mitochondria after recirculation for 3 days. The dendrites became severely degenerated after recirculation for 4 days. In the pyramidal cell bodies, no abnormality was observed at the end of ischemia for 5 min, but disaggregation of polyribosomes and swelling of the endoplasmic reticulum were observed 12 h after recirculation. Proliferation of the endoplasmic reticulum in parallel arrays occurred after recirculation for 1 day and persisted. Severe degeneration of the pyramidal cell bodies was obvious after recirculation for 4 days. The findings observed in the present investigation suggested that the neuronal structure most vulnerable to ischemia was the peripheral part of the dendrites and postischemic neuronal damage occurred early in this part of the dendrites.

Glioblastoma after Radiotherapy for Craniopharyngioma: Case Report

A 6-year-old girl developed a glioblastoma in the basal ganglia and brain stem 5 years after surgical excision and local irradiation (5460 cGy) for craniopharyngioma. Clinical and histological details are presented, and the literature on radiation-induced gliomas is reviewed.

Hypothalamic hamartoma: report of two cases.

Two histologically confirmed hypothalamic hamartomas, one in a 7-year-old boy and another in a 10-year-old boy, are reported. One patient had precocious puberty, epileptic laughter, and abnormal behavior; the other had cerebral seizures. Partial removal of the tumors had no effect on precocious puberty; however, behavior improved in the first patient, and seizure control improved in the second patient.

Hippocampal Neurons Become More Vulnerable to Glutamate after Subcritical Hypoxia: An in vitro Study

The neurotoxicity of glutamate and hypoxia was investigated in vitro on hippocampal neurons, which were obtained from 18-day-old rat fetuses and were maintained for 3 days in culture. Chemically defined medium without glutamate was used and the plating density was low enough that the effect of exogenously added glutamate could be directly evaluated. In the normal culture condition 1 mM glutamate was necessary to cause significant neuronal loss in the following 24 h. In marked contrast, when glutamate was added after subcritical hypoxic stress, a dose of glutamate as low as 10 μM could exhibit neurotoxicity. Administration of MK-801, a selective noncompetitive antagonist of the N-methyl-d-aspartate (NMDA) receptor, could in part reverse this increased susceptibility to low-dose glutamate after hypoxia, although MK-801 could not protect hippocampal neurons from high-dose glutamate. Therefore, both the NMDA receptor and other subclasses of the glutamate receptor may be involved in this neurotoxicity of glutamate. Different mechanisms of glutamate neurotoxicity with high and low doses are discussed. Our results showed that hippocampal neurons exposed to subcritical hypoxia become more vulnerable to glutamate than those without hypoxia. This increased susceptibility is of great interest to understanding the mechanism of slowly ongoing neuronal loss caused by ischemia or epilepsy.

Effect of brain-stem lesions on metrazol-induced seizures in cats

Abstract 1. 1. The chronic effect of bilaterally paired lesions in the cats brain-stem on Metrazol-induced seizures was studied in order to clarify the intracerebral mechanism for the maintenance of epileptic excitability. 2. 2. The results seem to indicate that there are two systems of facilitatory and inhibitory functions in the brain-stem rostral to the pons as far as Metrazol-induced seizure activity is concerned. The facilitatory system consists of the caudal mesencephalon extending rostrally to the posterior hypothalamus through the ventral part of the rostral mesencephalon and posterior sub-thalamus, and also of the medio-dorsal nucleus of the thalamus. the inhibitory system consists of the dorsal part of the rostral mesencephalon extending rostrally to the thalamus and also of the anterior hypothalamus. 3. 3. It may be suggested that this facilitatory system plays a significant role in the onset and generalization of the Metrazol seizure.

Autoradiographic Study of Regional Protein Synthesis in Focal Cerebral Ischemia with TCA Wash and Image Subtraction Techniques

The standard biochemical method of trichloracetic acid (TCA) wash and the image processing technique were combined to differentiate and visualize the distributions of polypeptide-incorporated and unincorporated tracers in an autoradiographic study of regional protein synthesis, The validity of applying TCA wash procedures to cryostat sections was considered by histologic and chemical evaluations, For the autoradiographic study of in vivo protein synthesis, a tracer dose of L-[14C]valine was administered 30 min after occlusion of the posterior communicating artery in gerbils. Images of total (polypeptide-incorporated and unincorporated) radioactivity and of polypeptide-incorporated radioactivity were obtained from an identical cryostat section before and after TCA wash. The polypeptide-unincorporated radioactivity image was produced with an image processing system by subtracting pixel by pixel the polypeptide-incorporated radioactivity from the total radioactivity. The present study clearly demonstrated that in spite of the sufficient delivery of tracer amino acids, the polypeptide synthesis was completely lost in the ischemic focus. Free tracer was markedly accumulated in the brain adjacent to the ischemic focus. This kind of autoradiographic technique seems to be indispensable in studying the topographical complexity of the altered protein metabolism in the pathologic brain.

Effects of bromocriptine on prolactin-secreting pituitary adenomas. Mechanism of reduction in tumor size evaluated by light and electron microscopic, immunohistochemical, and morphometric analysis.

Prolactin‐secreting pituitary adenomas were studied to clarify the mechanism by which bromocriptine reduces tumor size. Patients examined consisted of three groups: Group I (four cases) received no medication, Group II (six cases) continued bromocriptine treatment (10 mg/day for 2 weeks) until the operation, and Group III (five cases) discontinued the treatment 1 week before the operation. Adenomas in Group II showed a variety of degenerative and necrotic changes of tumor cells in addition to marked decrease in volume of individual cell. Adenomas in Group III showed divergent structural changes. Irreversible changes seen in Group II became more pronounced with a marked increase in stromal tissue. Proliferative areas consisting of intermediate‐sized cells were found in the scarce stromal tissue. The findings seem to indicate that the reduction in size of prolactinomas by bromocriptine treatment results from the reduction in size of individual tumor cell as well as from cell loss secondary to necrosis.

Malignant recurrence of childhood cerebellar astrocytoma: case report.

A 15-year-old boy developed a glioblastoma in a cerebellar hemisphere 7 years after surgical excision and local irradiation of a pilocytic astrocytoma in the cerebellar vermis. Clinical and histopathological details are presented, and the literature on late malignant recurrence of childhood cerebellar astrocytoma is reviewed.