The possibility of measuring the rCBV with CT-scanner, proposed by several authors, was based upon the assumption that extravasation of the contrast medium does not occur within 1 hour after intravenous administration if the blood-brain-barrier is intact. They have estimated the absolute value of rCBV in different slices of CT-scan by subtraction method. However, some authors have criticized the method itself and pointed out several technical disadvantages as well as the causes of failure.
We had opportunity to examine the rCBV with CT-scanner according to Ladurner's method and found that the estimated values showed significant aberrations. This made us to conclude that the enhancement value after the administration of contrast medium is should reflect the relative amplitude of the rCBV. In order to compare the relative value of rCBV of specified region with other cerebral area, for instance, contralateral corresponding area, a computer programming was established and applied to clinical investigation, especially in the cases of cerebrovascular diseases. Results obtained were as follows;
1) In Moya-Moya disease, rCBV in the site of lesion, was significantly less than the value of contralateral region. Although the patients showed neurological symptoms and signs due to ischemic process the CT-scan appeared within normal.
2) In patients with TIA's there was a consistent tendency that rCBV in the affected region was slightly larger than that of corresponding region. The TIA's might be attributed to sudden drops of increased rCBV at the site of lesion.
3) In patients with fresh cerebral infarction, rCBV surrounding the low density area of CT-scan was larger than that of corresponding area. As a possibility luxurious perfusion of the affected area was suspected.
4) The experimental works with 3 Japanese monkeys showed analogous change of rCBV to the clinical observation when acute cerebral infarction of the monkey was successfully established.

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Intracranial blood vessels are apparently innervated by catecholaminergic neuron. Until now, little is known about the function of these nerve plexes. Some scattered evidence suggests that these perivascular nerve has regulatory function toward cerebral circulation.
To find out its role, experimental cerebral ischemia was produced by temporary occlusion of middle cerebral artery (MCA) in rhesus monkey. Transorbital microsurgical technique was employed for exposing the origin of MCA. Cerebral blood flow was assessed by measurement of the cortical temperature (Tc), using thermister placed on anterior temporal lobe. Following the application of small Scoville clip to MCA, Tc on the same side fell down to certain degree (mean fall of Tc = -2.9 ± 0.6°C) and restoration of flow raised Tc to approximately the same degree (mean rise of Tc = +3.1 ± 0.7°C). Pressure autoregulation (PAR) of cerebral blood flow was examined following the elevation of mean arterial blood pressure by inflation of the aortic balloon.
Three hours occlusion of MCA did not harm PAR, but it became disturbed after five hours in control animals. Following presumptive chemical sympathectomy produced by administration of either L-alpha-methyl-tyrosine or 3-alpha-dimethyl-tyrosine, PAR appeared to be lost on the side of the occlusion alone when MCA occlusion lasted 1.5 hours or longer. Reactivity to hypercapnia and hypocapnia was preserved on both control and chemical sympathectomy groups even after MCA occlusion.
Based on these observations, it was suggested that sympathetic control of cerebral circulation was necessary for counteracting the postischemic vasodilatation with maintaining the proper pressure autoregulation.

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A prolonged vasospasm was produced in the canine basilar artery by administration of fresh autogenous arterial blood into the chiasmatic cistern. Lyophilized homogenates of normal and spastic canine basilar arteries as well as of blood clot around the spastic artery, were made, and their contractile activities were studied with the canine basilar artery in vitro. The lyophilized homogenates of the spastic artery and the blood clot induced a sustained, strong contraction, whereas those of the normal artery produced a transient, slight contraction. The contraction induced by the lyophilized homogenates of spastic artery was reduced slightly by methysergide and greatly by phentolamine. It may be suggested that vasoactive substances are present in the spastic artery as well as in its surrounding clot.

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Endoscopic intraventricular findings using an encephaloscope in 30 cases of ventriculitis and 60 cases of intraventricular hemorrhage were reviewed.
In cases of ventriculitis, encephaloscopic findings were classified into 4 stages, early (initial) stage, advanced stage, late (end) stage and recovery stage. Characteristic findings of the early stage were as follows : fibrin and debris floating in light yellowish or whitish turbid CSF and covering ventricular walls and whitish discolored choroid plexus. In the advanced stage, usually xanthochromic or turbid CSF without floating material and lusterless discolored wall with increased and dilated small vessels, sometimes pus or membranous material covering the ventricular wall and choroid plexus. In the late stage, watery clear CSF without floating material, and markedly dilated ventricles associated with enlarged Foramen of Monro. Characteristic abnormal substances were found in 17 of 30 cases, namely, string-like, rope-like, column-like, or membranous and quite often septal formation (septation) or multilocular cavitation (8 cases). In the recovery stage, after treatment, watery clear CSF with normal pressure and normal-sized ventricle, with few exceptions.
Cases of intraventricular hemorrhage with bloody CSF and high pressure had not always poor prognosis if not associated with clot, but if the Foramen of Monro was closed by a hard clot which was not easy to remove or suck out, the prognosis was usually poor. Sometimes endoscopic investigation revealed preforated holes from thalamic hemorrhage, intraventricular vascular tumor or arteriovenous malformation.
Experience with 18 cases of continuous intraventricular irrigation (CIVI) therapy for ventriculitis and intraventricular hemorrhage was also reported. Newly manufactured artificial CSF had been used since 1974, in a daily dose of 1, 000 to 1, 500 ml depending on the ventricular size. The dose of antibiotics using CIVI was 5-10 times more than that of one intraventricular injection. Duration of CIVI was 4 days to 2 weeks depending on the intraventricular conditions. Clinical safety and usefulness of CIVI with the artificial CSF was discussed.

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In the synchronized chemoradiotherapy of malignant brain tumors it is important to use a drug having a cell cycle phase specificity on G₂-M phase. Moreover, how to recruit G₀ cells to the proliferating pool during therapy is a problem of therapeutic importance for enhancement of the synchronizing effect. The present study was undertaken to elucidate the pharmacological mechanism of VM26 on cell kinetics.
Methods: The rat glial tumor C₆ cell line was cultured for 72 hours initially in the RPMI-1640 medium added with 20% FCS. When the cells were in the log phase, VM26 was added to the medium at concentrations of 0.01, 0.1, 1, 10 and 100 μg/ml and culture was continued for further 24, 48 or 72 hours. After these time intervals specimens were taken for the determination of live cell count and then of the cell cycle phase-distribution by the use of a pulse cytophotometer (ICP 11). Histograms of frequency distribution thus obtained were analysed mathematically for the calculation of percentages of G₀ + G₁, S and G₂ + M phases.
Results: VM26 was recognized to have pronounced cytostatic effect even at the lowest concentration of 0.01 μg/ml. Pulse cytophotometric analysis also showed that tumor cells became synchronized in G₂-M phase after 24-hour-contact with VM26 (1 μg/ml: 71%). S phase-block was not observed by the use of VM26. The histogram obtained at 48 hours of contact with the higher concentrations (1, 10 and 100 μg/ml) of VM26 showed the persistence of 2CDNA peak. The histogram obtained after 72-hour-contact with the drug at these higher concentrations suggested recruitment of G₀ cells to the proliferating pool.
VM26 may thus be expected to have a place in the synchronized chemoradiotherapy of malignant brain tumors.

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Transplantable gliomas of C57BL/6J mice were used in order to investigate the influence of immunological resistance against tumors transplanted in the right parietal lobe. Immunization was induced by subcutaneous inoculation of approximately 1 mm³ of tumor grafts, irradiated by 3, 000 watt.sec/cm² ultrasound or 3, 000 rad X-ray, once a week for 2 weeks to normal animals. Immunization was assured by tumor rejection or no growth 2 to 3 weeks after challenge of non-treated tumor implants. The rates of immunization against tumor were 67% by ultrasound irradiation and 45% by X-ray irradiation.
Passive transfer of resistance against the tumor was evaluated by IV injection of 1 × 10⁸ spleen cells from immunized animals to normal isologous animals. The result showed a 40% rate of transfer. The rate of tumor growth transplanted in the brain was 71 % in immunized mice induced by subcutaneous inoculation with no significant difference from normal mice (81%). However, survival intervals after transplantation were significantly longer (P<0.01), ranging from 17.6 to 23.7 days. The tumor was more localized and showed more degeneration. Lymphocytic infiltration into the brain tumor was much less pronounced than subcutaneous tumor in immunized animals and there was no marked glial reaction. Focal lymphocytic accumulations were sometimes observed in perivascular spaces and in the meninges, but there were no clear differences from non-immunized tumor-bearing mice. The population of T-cells in the spleen and the mesenteric lymphnodes was evaluated by acid α-naphthyl acetate esterase (ANAE) stain in imprint preparations and in freshly snap-frozen (-80°C) and cryostat-cut specimens of the spleen, lymphnodes and brain tumors. ANAE stain reported by Mueller in 1975 demonstrated one or two positive dots in T-cells. T-cells in the spleen and lymphnodes increased but only a few were detected in the brain tumor of the immunized animals. Direct immunofluorescent studies with FITC-labelled anti-mouse Ig antibodies were applied to freshly snap-frozen and cryostatcut specimens. As a result, Ig-cotaining cells infiltrated the tissues around the subcutaneous tumor while a few penetrated the tumor tissues. Fluorescence was not marked on the cytoplasmic membrane of brain tumor of immunized animals but was positive in those of nonimmunized animals and was more marked in those animals which showed tumor growth in spite of induction of immunization, suggesting that the blocking factor described by Hellstrom was involved.

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