Cerebral ischemia was produced by occlusion of the canine middle cerebral artery, and the changes in regional cerebral blood flow (rCBF) and somatosensory evoked potentials (SEP, V₁) were monitored for three hours following production of ischemia, under CO₂ inhalation or with a controlled intravenous infusion of Angiotensin II.
In mild ischemia, in which rCBF was decreased by 20 to 40% compared with the control, rCBF and SEP (V₁) significantly recovered during artificially induced hypercapnia (PaCO₂ 43 to 55 mmHg). However, hypertension caused no or only minimal changes in rCBF and SEP (V₁) in ischemia of this degree.
In moderate ischemia, in which rCBF was decreased by 40 to 60% compared to the control, rCBF and SEP (V₁) were significantly restored by artificially induced hypertension.
Induced hypercapnia and hypertension methods are promising as preoperative tests for predicting the resules of bypass surgery. However, care is needed in assessing the results of these tests since response of cerebral arteries by the two activating methods depends on the degree of ischemia.

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Anti-tumor effects of radiofrequency hyperthermia on experimental malignant glioma of rats were examined. Radiofrequency electromagnetic fields at 13.56 MHz were used to heat locally subcutaneously-transplanted Rous sarcoma virus-induced rat gliomas. Temperature profiles during radiofrequency treatment showed that the temperature in the tumor was constantly higher by 2 ?? 5°C than that in the surrounding subcutaneous tissue. The tumor temperature was maintained at a stable level throughout the treatment by adjusting the radiofrequency power.
Following results were obtained: 1) The critical temperature to bring about anti-tumor effects such as delay of tumor growth or extension of the survival of the animals was 43°C. 2) Longer or repeated heating enhanced the anti-tumor effects. 3) Combined therapy consisting of radiofrequency hyperthermia and ⁶⁰Co-irradiation or an anticancer drug, ACNU, showed greater anti-tumor effects than hyperthermia only.

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Transsphenoidal surgery on four cases of craniopharyngioma is reported. The usefulness of this method and operative indications for craniopharyngioma are discussed.
It may be concluded that this method is less invasive and safer for removal of the tumor, with preservation or even the possibility of improvement in the pituitary function, when the tumor is mainly located in the sella or slightly extended into the suprasellar portion. This was confirmed by a comparative study of the pre and post-operative hormonal state in three patients. To decide operative indications, it is necessary to demonstrate the exact location of the tumor. Pneumoencephalotomography, coronal and sagittal CT and/or metrizamide cisternography are the most reliable methods so far to delineate tumor extension. Admittedly, the absolute indication is mainly an intrasellar tumor with enlarged sella, although not many cases of craniopharyngioma are included in this type. Furthermore, transnasal drainage of the cyst or emergency decompression of the chiasm for suprasellar craniopharyngiomas may be indicated in some situations. For radical removal, it may be possible to use both the transsphenoidal and intracranial route simultaneously.

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Twenty-eight patients with cerebellar astrocytoma were treated at the Department of Neurosurgery, Brain Research Institute, Niigata University, between 1947 and 1980. There was one surgical death and two additional patients who died prior to posterior fossa surgery and were confirmed to have a cerebellar astrocytoma by autopsy. Thus, 25 patients were available for follow-up analysis. The surgical procedures, histological findings and the efficacy of radiation therapy as well as the clinical symptoms and signs have been presented.
Thirteen patients were under 15 years of age and 15 were over 16 years old. Eight patients died in the period from 9 months to 9 years (mean 2.6 ± 2.7 years) after posterior fossa surgery. Out of a total of 28 patients, 17 have survived for 1 to 26 years, and 13 of the 17 survivors have survived 10 to 26 years after their tumors had been operated on.
Among 15 patients who received partial excision of the tumor, eight are surviving and seven of them were irradiated. Four of the five patients who underwent subtotal excision are surviving. All of the five patients of total excision are surviving. All of the living patients were found to be in excellent or good neurological condition.
Radiation therapy was performed on 18 patients after posterior fossa surgery. Among 17 patients whose tumors were not totally excised during surgery, eight of 12 patients with radiation therapy are surviving, while only one of five patients without radiation therapy are surviving.
Sixteen out of 19 patients whose tumors were diagnosed as piloid, fibrillary or spongioblastic astrocytoma histologically are surviving. However, only one of six patients whose tumors were diagnosed as protoplasmic, diffuse-type or anaplastic astrocytoma have survived.
It is advocated that every effort should be made to extirpate the solid portion of the tumor as much as possible. However, if the tumor has invaded deeply into the brain stem or the floor of the fourth ventricle, surgical intervention should be stopped to avoid postoperative morbidity. Postoperative radiotherapy seems to have some effect on the prevention of recurrence of the tumor.

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Follow-up studies by cerebral angiography 4 to 11 years after the first angiography were carried out in six out of 44 cases with arteriovenous malformation of the brain (AVM) which were not operated on radically for various reasons. The size of the AVM was unchanged in five cases and spontaneous complete regression of the AVM was noted in one case. This 44 year-old man had a sudden attack of severe headache followed by disturbance of consciousness in April, 1968. Bloody CSF was noted in spinal taps. He was admitted in August, 1968. Vertebral angiography on admission showed an AVM of 1.4×1.1×1.0 cm in size in the left occipital lobe. The main feeder was the posterior cerebral artery and the drainer joined the vein of Galen. Craniotomy was performed, but no attempt was made to remove the AVM. Right hemiparesis and hemihypesthesia suddenly appeared and continued for 1 to 2 months four times from 1970 to 1978, but computerized tomography revealed no abnormal findings. The second angiography performed 10 years after the first study showed complete disappearance of the AVM. The same attack was noted in June, 1979 and the third study revealed reappearance of a small AVM.
Spontaneous disappearance of the AVM was also demonstrated in another case during admission. This 26 year-old man had a sudden attack of left hemiparesis in January, 1966. Right carotid angiography revealed a small AVM of 0.7×0.5×0.5 cm in size in the right parietal lobe. The main feeder was the pericallosal artery and the drainer joined the superior sagittal sinus. A small intracerebral hematoma was noted posterior to the AVM. He was treated conservatively. Angiography performed 3 months after the first study demonstrated complete disappearance of the AVM. The left hemiparesis recovered gradually and he returned to his job. No more attacks were noted for 7 years after discharge.
Ten cases, including the two present cases, showed spontaneous regression of the AVM and 33 cases with angiographically occult AVM were collected from the literature.
Thrombosis of the AVM associated with circulatory disturbance in and around the lesion due to repeated intracerebral bleeding from the AVM was suspected to be the main factor causing spontaneous disappearance of the AVM. Roles of advanced arteriosclerosis and the circulatory condition depending on the location of the AVM in spontaneous regression of the AVM were not clear in the present study.

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A 12-year-old boy was admitted in a comatose state following a sudden episode of headache and vomiting. General physical examination and vital signs at admission were normal. A difference was noted in pupil sizes, the right being slightly larger, and light reactions of both pupils were sluggish. Bilateral deep tendon reflexes were exaggerated and decerebrate posturing was elicited by noxious stimuli. There was right hemiparesis, but facial palsy was not be observed. A lumbar tap revealed an opening pressure of 230 mm H₂O and the fluid was bloody. Ventricular drainage was performed the following day.
Conray ventriculography showed a filling defect in the posterior end of the third ventricle, but the aqueduct of Sylvius and the fourth ventricle were not visualized. Computed tomography (CT) revealed the presence of a high density lesion in the area between the left paramedian pontine tegmentum and the fourth ventricle. It was diagnosed as a primary pontine hemorrhage, and a ventriculo-peritoneal shunt was performed. Left vertebral angiography failed to show any abnormal findings such as vascular malformation.
Ten days after admission, anisocoria disappeared. The patient's consciousness became clear one month after the onset. With improvement of the level of consciousness, the following abnormal neurological findings were noted. Ocular movement indicated the presence of the one-and-a-half syndrome, i.e., complete loss of horizontal movement of both eyes except for lateral gaze of the right eye accompanied by nystagmus. There were left peripheral facial palsy and right hemiparesis with exaggerated deep tendon reflexes plus a right Babinski response.
Right hemiparesis improved after about one year. A CT scan performed two years after the onset revealed a non-enhanced low density area in the pontine tegmentum where the hematoma had been located. At present, the patient is in good health and attending junior high school.

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Two cases of sellar-parasellar chordomas were experienced, the main symptoms of which were slowly progressive cranial nerve palsies.
Localized destruction of the sella turcica and a soft tissue mass protruding into the sphenoid sinus detected by CT and hypocycloid tomography were suggestive of sellar-parasellar chordomas. Endocrinological findings, size of the sella turcica and findings on contrast enhanced CT were helpful in differentiating them from pituitary adenomas. Cerebral angiography, metrizamide CT and hypocycloid tomography of the sella turcica suggested that the main mass was restricted to the epidural spaces, infiltrating into the sphenoid bone. The authors adopted transsphenoidal microsurgery, rather than craniotomy, to avoid injury to the dura mater and dissemination of the tumor cells in the cerebrospinal fluid pathway. The tumors were soft with few vessels and they were easily removed by suction and curettage, preserving the dura mater intact.

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Case 1. A 49-year-old woman was admitted because of a lump in the forehead. She had noticed a lump 5 years previously, and it slowly increased in size. She had been medicated with thyroxin for 2 months prior to admission because of the diagnosis of hypothyroidism and high serum thyroid stimulating hormone level (130 μu/ml). Physical and neurological examinations were normal except for the lump. Laboratory findings were normal. Plain skull films showed an osteolytic area with a reticular pattern and sclerotic margin in the frontal bone. A bone scintigram revealed an accumulation of radioisotopes at the lesion. A selective external carotid angiogram demonstrated feeding arteries from the middle meningeal artery and the superficial temporal artery, and a pooling of contrast material in the arterial through venous phases. A vascular tumor was removed en block. The histology revealed thinwalled dilated vessels between the trabeculae, which was diagnosed as a cavernous hemangioma of the frontal bone. Postoperative recovery was uneventful.
Case 2. A 59-year-old woman was admitted because of a mass in the right temporal region and right facial palsy. She had under gone thyroidectomy for thyroid carcinoma 6 years previously. Postoperatively, she had been medicated with thyroxin. She had noticed a lump on the right temporal region 4 years previously. She had stopped taking thyroxin one year prior to admission. The tumor slowly increased in size and she developed right facial palsy. On examination, she was noted to have a large tumor on the temporal region, right facial pasty of the peripheral type and a slight paresis of the left upper extremity. Plain skull films showed a large osteolytic lesion without reticular pattern or sclerotic margins in the temporal and the sphenoid bones. Computed tomography revealed a large, high and low density mass, which occupied the middle fossa and destroyed the temporal and sphenoid bones. A right common carotid angiogram demonstrated a pooling of contrast material in part of the tumor in the arterial through the venous phases. A vascular tumor was removed partially. The underlying dura was vascular and adherent to the tumor, but there was no invasion of the dura. Microscopically, this tumor was a cavernous hemangioma. Postoperatively, preoperative neurological signs improved.
Some authors suggested that trauma was one of the promoting factors of the tumor growth. In the two cases of the authors, there was no history of trauma but both had hypothyroidism. Some changes in hormonal environments may be one of the promoting factors of tumor growth.

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Pheochromocytomas are functionally active tumors which occur most commonly in the adrenal medulla but which can also develop in an extra-adrenal site. Over 90% of pheochromocytomas including extra-adrenal tumors are located between the diaphragm and the pelvic floor. Only two previous reports of pheochromocytoma originating from the cervical sympathetic chain were found in the literature. A thrid case of pheochromocytoma originating from the cervical sympathetic chain is presented.
The patient was a 18-year-old boy who was admitted to the Sapporo Medical College Hospital, because of attacks of palpitation, headache, generalized sweating and numbness in the four extremities during the past three years. Paroxysmal hypertention was noted and a high level of noradrenalin in plasma and urine was shown. The patient was diagnosed as having a pheochromocytoma. However, it was difficult to detect the tumor. A tumor, which was situated on the right side of the neck at the angle of the jaw became enlarged and palpable after one year. Selective angiography and CT were performed, and the tumor was removed. The tumor, which was 6×3.5×3.5 cm in size, had originated in the right superior cervical sympathetic ganglion. A pathological examination showed chromaffin paraganglioma or pheochromocytoma. The postoperative course was uneventful.

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The authors presented four cases of small vascular malformation (SVM) of choroid plexus in the lateral ventricle and reviewed the 21 cases reported since 1950.
Although 85% of the reported cases occurred in the first four decades of life, two of the authors' series were over 40 years old. The initial symptom was a subarachnoid hemorrhage in 85% of the reported cases and all cases in the authors' series. Focal neurological deficits were present in 33% of the reported cases and two of the authors' series.
Diagnosis of the lesion was made antemortem in 16 of the reported 21 cases and all of the authors' series. Eight of the 16 cases were diagnosed by angiography, two by CT scan, five at the time of operative exploration for intracerebral hematoma or mass lesion in the lateral ventricle and one after plexectomy for hydrocephalus. Among the 15 reported cases with cerebral angiography, the feeding artery, nidus and draining vein were visualized in only seven cases. Case 1 and Case 2 of the authors' series showed similar angiographic findings. Histologically these SVMs were all arteriovenous malformations (AVM).
However, only one of the six reported cases of SVM classified as either cavernous, or venous angioma or teleangiectasis revealed a small vascular area of radiopaque material. In Case 3 of venous angioma, serial angiography showed a very small, spotted vascular lesion in the early arterial phase, and revealed a nearly homogeneous area of contrast material of small size in the venous phase. In Case 4 of cavernous angioma, both a small vascular lesion and early venous filling were demonstrated by serial angiography.
CT scans revealed abnormal vascular lesions in two out of four reported cases of choroid plexus SVM in the lateral ventricle. It was possible to detect the precise anatomical location of the SVM, such as whether a lesion was confined to the choroid plexus or involved deep nuclei. CT scans were also valuable as shown in Case 4 for the identification of cavernous or venous angioma which sometimes did not show apparent angiographic findings. CT scans safely showed either the extent of the hematoma or the degree of hydrocephalus accompanying the SVM.
In conclusion, the authors emphasize that in cases of subarachnoid hemorrhage with neither aneurysms nor macroangioma, the possibility of the presence of choroid plexus SVM in the lateral ventricle must be considered. A combination of serial and magnification angiography, the film subtraction technique and CT scanning is very useful and necessary in identifing this type of lesion.

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Actinomycosis of the central nervous system is very rare. A man aged 48 was admitted to the Ekisaikai Hospital with tetraparesis and urinary obstruction. Myodil myelography showed a complete block at Th4. Laminectomy was carried out from C6 through Th5. Epidural granuloma was found and removed subtotally. The vertebra was not eroded. Pathological diagnosis was actinomycotic granuloma. No cervicofacial, thoracic, or abdominal focus was found. Two years after the operation, he has now completely recovered. This case is probably the first report of spinal epidural actinomycotic granuloma.

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