Cerebral blood flow and cerebral hematocrit in patients with cerebral ischemia measured by single-photon emission computed tomography.

Single-photon emission computed tomography (SPECT) was used for the measurement of regional cerebral blood flow (CBF), cerebral blood volume (CBV) and cerebral hematocrit (Hct). CBF was measured using N-isopropyl-p-I-123-Iodoamphetamine. CBV was measured by both RBC tracer (Tc-99m RBC) and plasma tracer (Tc-99m human serum albumin) and cerebral hematocrit (Hct) was calculated. In normals, the cerebral-to-large vessel Hct ratio was 75.9%. Isovolemic hemodilution in patients with high Hct tended to increase the cerebral-to-large vessel Hct ratio. Low CBF, high CBV and slow cerebral blood mean transit time (MTT by dynamic CT scanning) was seen during the acute stage of completed infarction and during the symptom-free interval of TIA. Cerebral Hct was increased in the ischemic region of poor prognosis.

Regional cerebral blood volume and hematocrit measured in normal human volunteers by single-photon emission computed tomography.

Single-photon emission computed tomography (SPECT) was used for the measurement of regional cerebral blood volume (CBV) and hematocrit (Hct) in normal healthy human volunteers (mean age 30 +/- 8 years). Regional cerebral red blood cell (RBC) volume and plasma volume were determined separately and their responses to carbon dioxide were investigated. Ten right-handed healthy volunteers were the subjects studied. SPECT scans were performed following intravenous injection of the RBC tracer (99mTc-labeled RBC) and plasma tracer (99mTc-labeled human serum albumin) with an interval of 48 h. Regional cerebral Hct was calculated as the regional ratio between RBC and plasma volumes and then was used for calculating CBV. Mean regional CBV in the resting state was 4.81 +/- 0.37 ml/100 g brain, significantly greater in the left hemisphere compared with the right by 3.8% (p less than 0.01). Mean regional RBC volumes (1.50 +/- 0.09 ml/100 g brain) were less than mean regional plasma volumes (3.34 +/- 0.28 ml/100 g brain), and mean regional cerebral Hcts were 31.3 +/- 1.8%, which was 75.9 +/- 2.1% of the large-vessel Hct. During 5% CO2 inhalation, increases in plasma volume (2.48 +/- 0.82%/mmHg PaCO2) were significantly greater than for RBC volume (1.46 +/- 0.48%/mmHg PaCO2). Consequently, the cerebral-to-large-vessel Hct ratio was reduced to 72.4 +/- 2.2%. Results emphasize the importance of cerebral Hct for the measurement of CBV and indicate that regional cerebral Hcts are not constant when shifted from one physiological state to another.

Primary leptomeningeal ependymoblastoma. Case report.

Ependymoblastoma is considered to be a primitive malignant glioma with ependymal differentiation. This rare tumor occurs in very early life and shows rapid growth and a diffuse infiltration through the leptomeningeal space. The tumor cells are highly immature, with numerous mitoses and multilayered ependymal rosettes. The ependymoblastoma described in this report was found in a 17-year-old girl. In spite of detailed clinical and postmortem examinations, no definite primary site was identified in the neuraxis. The lesion spread predominantly throughout the leptomeningeal space. Histological analysis strongly suggested that this tumor originated from a heterotopic glial nest in the subarachnoid space. The absence of immunohistochemical neural tissue markers, glial fibrillary acidic protein, S-100 protein, neuron-specific enolase, and neurofilaments ruled out neuronal or glial differentiation. The authors were unable to find any previous report of primary leptomeningeal ependymoblastoma.

Clinical effect of Encephabol (pyritinol) in the treatment of cerebrovascular disorders.

The results of a series of multicentre, controlled, double-blind trials of the clinical efficacy of Encephabol compared with placebo in patients with a variety of cerebrovascular disorders are reported.

[Clinical aspects of brainstem infarction].

Ischemic stroke in the vertebrobasilar arterial territory often presents stunning signs and symptoms, and poses little difficulty in the clinical diagnosis. But in less dramatic cases, it is often difficult to make accurate clinical diagnosis and to document the precise extent of an infarct. The purpose of the present study is to demonstrate clinicotopographic correlations in patients with various brainstem and cerebellar infarctions and to reevaluate the importance of bedside clinical examinations for understanding pathophysiology and planning management of the patient. One hundred forty-three patients with clinical diagnosis of the vertebrobasilar infarction confirmed by MRI were studied. MRI is superior to CT scanning in delineating areas of infarction in the territory of posterior cerebral circulation because of the three dimensional approach and the lack of bone artifact. MRI also allowed very precise clinicotopographic correlations even in patients with good recovery, in whom pathologic verification of the lesion is not possible. There are some restrictions of MRI diagnosis to detect the clinical features which change from hour to hour, because of the mechanical limitation in spatial resolution and of the temporal uncertainty of the lesions such as reversible edema or coincidental asymptomatic old lesions. Clinical importance of ocular signs (eg. skew deviation, gaze limitations, nystagmus, pupillary abnormalities and so on) was discussed. Some eye-movement abnormalities (eg. gaze paresis, MLF syndrome, 'one-and-a-half' syndrome, lateropulsion or contrapulsion of eyes, and vertical nystagmus at the primary position) served as useful localizing signs, and especially their consecutive observations were of importance for clinical local diagnosis. Clinical syndromes, caused by lacunar lesions located either in the supratentorial or in the infratentorial structures, such as pure motor hemiparesis and ataxic hemiparesis were also discussed. In some cases of these syndromes, MRI failed to document the precise lesion responsible for the episode due to the multiplicities of small asymptomatic lesions. Even in such cases, detailed clinical informations (temporal profiles of the episode, past medical histories, neuro-ophthalmic signs and so on) may enable the differential diagnosis. It is concluded that the use of new imaging techniques such as MRI may provide new insights in the diagnosis of cerebrovascular diseases, but the importance of clinical observations can not be overemphasized.

[Isolated angitis of the central nervous system--case report and review].

Isolated angitis of the central nervous system (IACNS) is rare condition with inflammation limited to vessels supplying the brain. This IACNS has been a poorly characterized and infrequently reported illness since it was first described as a separate entity in 1959. However, a patient with IACNS has not been reported in Japan. A patient, 39-year old-male, with IACNS limited to small and middle vessels is described. Recurrent, transient consciousness disturbances, focal myoclonus, papilloedema and temporal lobe epilepsy were observed during disease course. CSF finding of this patient showed lymphocytosis with marked increased protein. Carotid and vertebral angiogram showed irregular luminal outline in branches of all arteries. The most specific finding is that of alternating areas of focal stenosis and ectasia giving a "sausage" pattern. These characteristic findings showed in the branch of external carotid arteries. There was no evidence of systemic vasculitis by systemic angiography. Biopsy of temporal artery showed lymphocyte infiltration, fibrinoid necrosis without giant cell and granuloma. Formation of A-V malformation in the branch of external carotid artery was also observed. This histopathological finding was compatible with necrotizing angitis, not granulomatous angitis. Isolated angitis of the central nervous system was diagnosed. In spite of his administration of corticosteroid, cerebrospinal fluid abnormalities has not responded markedly. Abnormal findings of carotid and vertebral angiogram also has not changed. After 7 years from his onset, his neurologic signs and symptoms were well controlled with administration of anti-epileptic drugs.

[Pathogenesis of ipsilateral hemiparesis in patients with lateral medullary syndrome].

Lateral medullary syndrome is known to cause hemiparesis ipsilateral to the medullary lesion. However, it's clinical significance has not been fully evaluated. In this study, we made clinical and angiographic studies in patients with syndrome to elucidate the pathogenesis of ipsilateral hemiparesis. Thirty-four patients with cerebral infarction presenting with this syndrome were studied. Their mean age was 51 years and all the patients were examined within 6 months of their first attack. Diagnosis of ipsilateral hemiparesis was made if subjective feeling of weakness in the upper and lower extremities was associated with increased deep tendon reflexes. Ipsilateral hemiparesis was observed in 38% of all the patients. Cerebral angiography was performed in 26 patients and divided into two groups; group A with ipsilateral hemiparesis (n = 9) and group B without ipsilateral hemiparesis (n = 7). In 56% of patients in group A, angiography showed non-visualization of ipsilateral vertebral artery (VA) and posterior inferior cerebellar artery (PICA). Non-visualization of these two arteries never occurred in the patients of group B. On the other hand, non-visualization of VA alone was observed in 35% of the patients in group B, but it was none in the patients of group A. However, there were no differences in concerning the frequency of non-visualization of PICA alone or non-occlusion at all between both groups. Therefore, the focal ischemia in the region below the pyramidal decussation due to the occlusion of both VA and PICA, regardless of thrombotic or embolic episode, was considered to be responsible for ipsilateral hemiparesis.(ABSTRACT TRUNCATED AT 250 WORDS)

[Neurological and neuroimaging studies of eclampsia].

Clinical and neuroimaging studies were made in twenty-one patients during the attack of eclampsia. Most frequent neurological signs and symptoms were the impairment of consciousness, headache, seizure and visual disturbance. Mean arterial blood pressure increased by 46 mmHg (n = 21) during the attacks. Eight of 9 patients studied by CT and/or MRI showed transient abnormalities on brain images during the attack in the occipital cortex, basal ganglia, and internal and external capsule. The findings were compatible with brain edema and were seen mainly in the white matter. Cerebral blood flow measured by SPECT method in one patient during an attack with visual disturbance showed increased blood flow in the occipital cortex. Acute increase in blood pressure, cerebral hyperperfusion and edema, similar to the pathophysiology of hypertensive encephalopathy, were considered to play an important role in the pathogenesis of eclampsia.

A morphological study for isolation of a single rat trigeminal motoneuron.

We conducted a morphological study for isolation of a single neuron to investigate the electrophysiological properties of trigeminal motoneurons in a further study using the patch clamp technique. Transverse slices of rat brain stem containing the trigeminal motor nucleus (200-300 microns thick) were prepared and stained by the methylene blue staining method. The trigeminal motor nuclei, approximately 1,000 microns in diameter, were identified as densely stained regions in the slices. The somata of motoneurons were classified into two types by shape; ellipsoidal and spherical. The ellipsoidal somata were 50.3 +/- 12.3 microns (mean +/- S.D., n = 290) in long axis and 21.8 +/- 5.3 microns (n = 290) in short axis. The spherical somata were 35.0 +/- 6.9 microns (n = 290) in long axis and 29.3 +/- 5.7 microns (n = 290) in short axis. The neurons were all multipolar with 2-8 dendrites emanating from the soma.

Multi-platform experiment to cross a boundary between laboratory and real situational studies: experimental discussion of cross-situational consistency of driving behaviors.

We constructed an innovative experimental platform to study cross-situational consistency in driving behavior, conducted behavioral experiments, and reported the data obtained in the experiment. To discuss cross-situational consistency, we separated situations in which people use some systems to conduct tasks into three independent conceptual factors: environment, context, and system. We report the experimental results with the following systems: a laboratory system with a gaming controller and steering/pedal controllers and a real system, COMS an instrumented vehicle. The results are summarized as follows. 1) The individual behaviors in each system were stable, and consistency was retained. 2) The consistency of the behaviors was also confirmed when the participants drove using different interfaces in identical systems. 3) However, only slight correlation was observed across different systems in a specific situation where a strong high-order cognitive constraint (i.e., rapid driving) and a weak low-order cognitive constraint (driving with easy handling toward a straight-line course) were given.