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Biomedical subjects

C Ohye

Publications and source records attributed to C Ohye.

At least 73 records · Page 4Linked to original sources
PubMed1992

[Anaplastic astrocytoma 14 years after radiotherapy for pituitary adenoma].

A case of anaplastic astrocytoma following radiotherapy for growth hormone secreting pituitary adenoma is presented with a review of the literature. A 43 year old female was admitted with the signs of acromegaly and hypertension. An eosinophilic pituitary adenoma was subtotally removed by transsphenoidal approach, and followed by 60 Gy irradiation using a 2 x 2 cm lateral opposed field. Fourteen years later at the age of 57, she suffered from headache, recent-memory disturbance and uncinate fits. CT scan and MRI disclosed ring-like enhanced mass lesion in the left temporal lobe, corresponding to the previous irradiated field. 18F-FDG PET showed hypermetabolism at the lesion. Left frontotemporal craniotomy was performed, and a reddish gray gelatinous tumor containing necrotic center and cyst was partially removed. Histologically, the tumor consisted of hypercellular astrocytic cells with perivascular pseudorosette. Coagulation necrosis at the center of the tumor, and hyalinosis and fibrosis of the blood vessels in and around the tumor, which might have been caused by the antecedent radiotherapy, were recognized. Postoperative radio- and chemotherapy were given, however, she expired 13 months after the operation. Seven cases, including ours, of malignant glioma following radiotherapy for pituitary adenoma were reported in the literature. A total dose of irradiation varies from 45 to 95 Gy with a mean of 50 Gy. The period of latency before tumor occurrence ranges from 5 to 22 years with a mean of 10 years. The differentiation of radiation-induced gliomas from radionecrosis of the brain is also discussed.

Adenoma↗
PubMed1991

Stereotactic Vim-Vo-thalamotomy for choreatic movement disorder.

Two cases with hemichorea and dopa induced dyskinesia (DID) were successfully treated with Vim-Vo thalamotomy. The findings of MRI and PET of these cases were variable because of the difference of their underlying disease processes. In the patients with hemichorea, high electrical activities with irregular bursts of discharge were recorded in Vo and Vim. These may be related to dysfunction of Vo underlying choreatic movement. Regardless of the causes, their choreatic movement was abolished by Vim-Vo thalamotomy affecting mainly Vo after physiological identification of Vim.

Adult↗
PubMed1991

Pathophysiology of central (thalamic) pain: a possible role of the intralaminar nuclei in superficial pain.

In 15 patients with central pain (thalamic pain) after stroke, CT, PET scan and intraoperative thalamic microrecordings were performed. The results are considered together to evaluate a possible role of thalamic intralaminar nuclei in the genesis of central pain, especially of superficial pain. In the non-thalamic lesion group (deep pain dominant), thalamic background neural activity (BNA) was relatively high in Vim but low in CL. Conversely, in the thalamic lesion group (superficial pain dominant), thalamic BNA was higher in CL than in Vim, and markedly decreased in VC. In this group, regional cerebral oxygen consumption (rCMRO2) was relatively maintained, and regional oxygen extraction ratio (raOEF) and the relative value of regional cerebral glucose utilization (CMRGL), compared to rCMRO2, was increased in the cerebral cortex around the central sulcus. The genesis of superficial pain is discussed.

Aged↗
PubMed1991

[Multiple liver metastases of a suprasellar germ cell tumor treated with combined chemotherapy of cisplatin and etoposide].

A 23-year-old man was admitted with progressively disturbed vision and easy fatigability. CT scans demonstrated an enhanced mass in the sellar region. Physical and endocrinological examinations revealed atrophy of both optic nerves, temporal field cuts in both eyes, and panhypopituitarism. Concentrations of human chorionic gonadotropin (HCG) in the serum and cerebrospinal fluid were 12 and 33IU/L, respectively. On November 11, 1987, the tumor was partially removed using the transsphenoidal approach. The histological diagnosis was germinoma with syncytiotrophoblastic giant cells. Following postoperative craniospinal irradiation (whole brain, 30Gy; local, 18Gy; spinal canal 28Gy), CT scans showed no residual tumor and the HCG levels decreased until they were undetectable. Eighteen months later, the patient complained of abdominal pain. His serum HCG level had increased to 2,554 IU/L. CT scans of the abdomen revealed multiple low density areas in the liver. Chest X-ray was negative. A Ga scintigram disclosed only liver metastasis. Administration of a chemotherapy was started on June 26, 1989. Cisplatin and etoposide in doses of 20mg and 40mg respectively were given for 5 consecutive days in one course. Following four courses of the combined chemotherapy, the tumor entirely disappeared on CT scans and the HCG level returned to normal. The patient is now able to work well without evidence of recurrence. Multiple liver metastases of an intracranial germ cell tumor had been fatal in previous reports. This may be the first case with liver metastases in which the victim is still alive. The present case indicates that combined chemotherapy with cisplatin and etoposide is effective for extraneural metastases of an intracranial germ cell tumor.

Adult↗
PubMed1990

Adjunctive treatment for recurrent childhood ependymoma of the IV ventricle: chemotherapy with CDDP and MCNU.

The prognosis of recurrent IV-ventricle ependymoma in children is poor. Three cases of recurrent ependymoma were treated with combination chemotherapy using cis-diamine dichloro platinum (II) (CDDP) and methyl-6-(3-(2-chloroethyl)-3-nitrosoureido)-6-deoxy-alpha-D-glucopyrano side (MCNU). The patients were 2-, 3-, and 6-year-old boys. The interval between the first operation with irradiation and recurrence was 1 year and 5 months to 2 years. Two cases showed a recurrence at the original site; in the other case, a right sylvian tumor deposit was found via computed tomography. The therapeutic regiment for recurrent ependymomas was as follows: (1) the tumor was debulked if possible; (2) additional local irradiation of 30 Gy was administered; (3) combined treatment of 100 mg/m2 CDDP and 80 mg/m2 MCNU over 24 h was given 5 times with an interval of 6 weeks between treatments. The patients tolerated the therapy well with only mild side effects. Remission lasted 1 year in two patients and has lasted for 8 months in one.

Antineoplastic Agents↗
PubMed1990

Strategy of selective VIM thalamotomy guided by microrecording.

Our routine procedure for stereotactic selective Vim thalamotomy is described briefly. Preoperative steps identify the tremor qualitatively and quantitatively. The highlight of the procedure is the use of intraoperative microrecording to determine tremor time-locked rhythmic discharge in the presumed Vim nucleus. Results of the operation are also estimated quantitatively.

Electrocoagulation↗
PubMed1989

Undifferentiated gliomas of the brain stem.

Undifferentiated gliomas of the brain stem were confirmed surgically in two young children. The patients were treated by aggressive irradiation of the entire neuraxis, similar to that administered for medulloblastoma. Therapy resulted in a good prognosis and there was no tumor recurrence.

Brain Neoplasms↗
PubMed1989

Cytometric analysis of the thalamic ventralis intermedius nucleus in humans.

1. The cytoarchitecture and the exact borders of the thalamic ventralis intermedius (Vim) nucleus of humans as originally delineated by Hassler (17) have been studied on the basis of stereotaxic coordinates correlated with Nissl- and Golgi-impregnated sections, using a microscopic image analyzer. 2. The Vim nucleus forms part of a relatively "cell-sparse zone" which includes the other ventrolateral thalamic subnuclei. It is distinguished by the presence of darkly stained, large and medium sized, angular cells with areas of approximately 500-1,000 microns 2 and 300-400 microns 2, respectively, and a cell density of approximately 50-90 (mean 65)/mm2 in 50-microns-thick sections. 3. Both sets of neurons have the characteristics of thalamocortical relay neurons in Golgi preparations. Large neurons have rectangular or square somata 30-50 microns diam and are concentrated mainly in the lateral and ventral two-thirds of the nucleus. The medium neurons have square to round somata, 15-25 microns diam, and are distributed homogeneously through the nucleus. The total dendritic arborization of both types is usually symmetrical in all directions and at least 500-600 microns diam. 4. The borders between the Vim nucleus and the Nucleus ventrooralis (Vo) and between the Vim nucleus and the Nucleus ventrocaudalis internus (Vci) are clearly identified by clearcut differences in cell size and cell density. The borders between the Vim nucleus and the Nucleus ventrooralis internus (Voi) and between the Vim nucleus and the Nucleus zentrolateralis intermedius (Zim) are quite obscure, and these nuclei, with Vim, seem to be parts of the large cell sparse zone comparable to that described in monkeys as VLp or VL. The border between the Vim nucleus and the Nucleus ventrocaudalis externus anterior (Vcea) is also unclear but the increased cell density and intermingling of small and medium-to-small neurons with large neurons are the major features that distinguish the Vcea nucleus from the Vim nucleus cytometrically. 5. The position and anatomic organization of the human Vim nucleus make it likely that it is the region in which kinesthetic response were recorded in the accompanying paper but extension of the recording sites into the Vcea nucleus cannot be ruled out.

Aged↗
PubMed1989

Further physiological observations on the ventralis intermedius neurons in the human thalamus.

1. During the course of stereotaxic thalamotomy for 56 cases with tremor mainly due to Parkinson's disease and essential tremor, extracellular recordings were made from the thalamic ventralis intermedius (Vim) nucleus under local anesthesia. These procedures have been justified as an essential technique to achieve the best therapeutic results by a selective coagulation. These physiological observations provide important information about the functional organization of the ventrolateral thalamic mass in humans. 2. Using Leksell's stereotaxic apparatus, a pair of semimicroelectrodes was introduced simultaneously to the thalamic ventral lateral region from the prefrontal area. The Vim nucleus was identified tentatively by characteristic high background activity which contrasted to that found in its rostral part and by superimposed large amplitude spontaneously active units. 3. In this high activity zone, 135 units (approximately 1/5 of the recorded units) responded to natural stimulation applied to contralateral body parts. Among them, approximately 90% responded to a passive or active movement of a joint. Several lines of evidence suggested that probably muscle receptors were responsible. 4. The rest of units (approximately 10%) responded to light touch applied to contralateral skin surface. Convergent responses between kinesthetic and tactile units were never encountered. Also, kinesthetic and tactile neurons were geographically separated. The latter were found always at the end of our oblique trajectory, following the kinesthetic neurons. 5. Neurons with sensory responses were clustered mostly within the confines of the Vim nucleus, probably extending caudally to the ventrocaudalis externus anterior of Hassler. Evidence for a somatotopic representation in the Vim nucleus was obtained. 6. Electrical stimulation of the appropriate peripheral nerve produced responses of the same thalamic unit(s) that responded to natural stimulation. The latency to upper limb nerve stimulation was between approximately 10 and 20 ms. It was almost fixed in a given case. 7. It is concluded that the Vim nucleus receives kinesthetic afferent input from the contralateral body parts (mainly from the muscle receptor) and may be concerned with muscle sense. This may explain why a small, selective coagulation of the physiologically identified Vim has such a constant effect on several different kinds of tremor.

Action Potentials↗
PubMed1989

Microrecording for the study of thalamic organization, for tumor biopsy and removal.

Use of microrecording technique in stereotactic selective thalamotomy, and in stereotactic biopsy for deep-seated lesions and in tumor removal was briefly described. For selective thalamotomy, the microrecording gives ample information to delineate thalamic subnuclei. Thus, the ventrointermedius (Vim) nucleus is identified by high-amplitude background activity and large-spike discharge, some of which responds solely to contralateral natural stimuli of kinesthetic modality. A small coagulation including this thalamic Vim point resulted in permanent arrest of the various kinds of tremor. As the normal brain tissue, whether the gray or white matter, is electrically active, the microrecording is useful to delineate the brain tumor from its surroundings. Stereotactic diagnostic biopsy and removal of the brain tumor were facilitated by this adjuvant method.

Biopsy↗
PubMed1989

[Autopsy cases of glioblastoma multiforme: treatment results of high-dose fractionated radiation therapy and CT scan findings].

Six autopsy cases of glioblastoma multiforme in cerebral hemisphere were examined by large histological preparations. They were treated by surgery and high-dose fractionated radiation therapy (5 Gy twice weekly). Their morphological changes were compared to the last CT and radiation field and total doses. Four out of six cases showed small residual tumor. One case showed extensive necrosis of the tumor and brain. The other case exhibited no tumor tissue at all. Spongy degeneration of the white matter associated with astrocytosis and macrophage infiltration extended sometimes beyond the local irradiation field. These white matter changes were easily occurred in the previous peritumoral edema where tumor cell infiltration was frequently observed. Residual tumor cells consisted of small anaplastic cells, which might be radioresistant and recur. Enhancement effect of CT scan showed tumor tissue and radiation necrosis with vascular proliferation.

Adult↗
PubMed1987

Neural circuits involved in parkinsonian motor disturbance studied in monkeys.

The outline of neurophysiological studies on a parkinsonian model in monkeys with mesencephalic ventromedial tegmental lesions was presented. By radiologically and physiologically controlled, selective deep-seated lesions, rigidity with or without tremor could be produced separately. From the results obtained mainly by microrecording from various levels of the brain, a neural circuit involved in production of rigidity and tremor has been proposed.

Animals↗
PubMed1986

Long-term follow-up results of selective VIM-thalamotomy.

The authors report the results of a long-term follow-up study of the effects of the physiologically defined selective VIM (nucleus ventralis intermedius)-thalamotomy on tremor of Parkinson's disease in 27 patients and essential tremor in 16 patients. The follow-up period ranged from 3.25 to 10 years (mean 6.58 years). In 43 patients a total of 50 operations (including four bilateral operations and three reoperations) were carried out. The early (2 to 4 weeks after surgery) and late effects on the tremors were determined clinically and electromyographically. Fourteen parkinsonian cases were treated with minimal lesions (about 40 cu mm). Their late results were very similar to the early results: in 10, the tremors were completely abolished, three had a slight residual tremor, and one underwent reoperation 3 months after the first surgery. Eleven essential tremor cases were treated with minimal lesions. Six of these tremors were completely abolished, four patients had slight residual tremors, and one patient with a recurrence underwent reoperation 2 years after the initial surgery. In these 23 successful operations with minimal lesions (excluding two cases with reoperation), the tremor was abolished without discernible long-lasting side effects. The other 23 operations on 16 patients with Parkinson's disease (including one reoperation) and on seven with essential tremor (one of whom also had a minimal lesion on the other side) involved relatively large lesions. In this group, the surgery was successful in almost every case. It was concluded that radiographically and physiologically monitored selective VIM-thalamotomy for parkinsonian and essential tremor is effective even when lesioning is minimal. Moreover, the beneficial effect is maintained over a long period of time.

Adult↗
PubMed1986

[Role of thalamic nuclei in the hypertonia and tremor of Parkinson disease].

Intraoperative recordings allowed the ventralis intermedius nucleus (Vim) to be distinguished from the ventrolateral nucleus (VL). Characteristics of the Vim include marked spontaneous activity, bursts synchronous with tremor, response of certain cells to contralateral kinesthetic and peripheral electric stimuli and paresthesia provoked by an intraoperative stimulus. Coagulation of Vim abolishes tremor while coagulation of VL abolishes hypertonus.

Brain Mapping↗