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N Komai

Publications and source records attributed to N Komai.

At least 127 records · Page 7Linked to original sources
PubMed1987

Regulation of rCBF by intracortical vasoactive intestinal polypeptide-containing neurons. Immunohistochemical and hydrogen clearance study in rats.

The role of intracortical vasoactive intestinal polypeptide (VIP)-containing neurons in the regulation of cortical blood flow was investigated in rats by immunohistochemical and hydrogen clearance methods. Immunohistochemical studies revealed an intimate association between intracortical VIP-containing neurons and small blood vessels. Intracortical injection of a VIP solution (10(-5) M) produced significantly higher blood flow in the treated cortex (mean +/- standard error of the mean: 46.2 +/- 4.0 ml/100 gm/min) than in the untreated cortex (36.9 +/- 2.4 ml/100 gm/min). These data suggest that intracortical VIP-containing neurons produce dilatation of intracortical blood vessels.

Animals↗
PubMed1987

[Primary T-cell type lymphoma of the central nervous system: a case report].

A case of T cell type primary lymphoma of the CNS is reported. A 50-year-old man was admitted because of speech and memory disturbance and dyscalculia. He had suffered from uveitis of both eyes two years before admission. Neurological examination revealed motor aphasia, finger agnosia, dyscalculia and memory disturbance. CT scan showed a mass lesion which was enhanced irregularly by the contrast medium in the left temporoparietal region. CAG confirmed the presence of a left temporoparietal avascular mass. Total removal of the tumor was performed through the left temporoparietal craniotomy. Histopathological diagnosis of the tumor was malignant lymphoma (diffuse, large cell type). Immunological study with tumor cells in the cerebrospinal fluid revealed that the tumor was T cell type malignant lymphoma. After postoperative whole CNS irradiation and intrathecal methotrexate injection, his preoperative symptoms disappeared. No evidence of the tumor recurrence is seen under CT scan one year and two months after the tumor resection. Relationship between the cell type of the tumor and CT findings is discussed.

Brain Neoplasms↗
PubMed1986

The distribution of adrenergic receptors in cerebral blood vessels: an autoradiographic study.

The first morphological evidence of the existence of adrenergic receptors (alpha 1, alpha 2 and beta) within the vascular walls of the central nervous system were presented using the in vitro receptor autoradiographic technique. In the rat pial arteries all three types of adrenergic receptors were demonstrated, whereas the human pial arteries failed to show significant autoradiographic grains of alpha 1 type of adrenergic receptors indicating a considerable inter-species difference in the distribution of adrenergic receptors. alpha 2 and beta receptors in human pial arteries were found not only in the arterial smooth muscle layers but also in the endothelial layers. This suggests a possibility that circulating sympathomimetic agents play some role in controlling the tone or permeability of vascular walls within the central nervous system. A distinct distribution of alpha 1 receptors in cortical layer IV where the vascular plexus was richest may suggest a relation of alpha 1 receptors and blood flow of brain parenchyma.

Animals↗
PubMed1986

Three dimensional observation of the nerve fibers along the cerebral blood vessels.

Three dimensional observation of the nerve fibers along the cerebral blood vessels was investigated by scanning electron microscopy. Electron probe X-ray microanalysis was also performed in the cerebral blood vessels treated with peroxidase-antiperoxidase immunohistochemistry intensified by nickel ammonium sulfate. Nerve fibers (2-8 microns in diameter) formed a plexus on the outer surface of the adventitia. After branching, the nerve fibers penetrated the blood vessel adventitia. Substance P-immunoreactive nerve fibers showed a meshwork pattern in the outer layer of the adventitia, and vasoactive intestinal polypeptide (VIP)-immunoreactive nerve fibers revealed a spiral running pattern in the inner layer of the adventitia. Taken together with previous studies, these findings suggest that substance P nerve fibers in the cerebral arteries may not be related to arterial dilatation or constriction, but VIP nerve fibers may be vasodilative.

Animals↗
PubMed1986

Hemorrhagic infarction after vasospasm due to ruptured cerebral aneurysm.

Hemorrhagic infarction after vasospasm is a rare condition in patients with aneurysmal subarachnoid hemorrhage (SAH). Induced hypertensive therapy is used for patients with vasospasm, but this treatment has a risk of inducing hemorrhagic infarction. A total of 221 patients whose first computed tomographic (CT) scans were examined within 2 weeks after SAH were investigated for this study. There was symptomatic vasospasm in 99 (45%), cerebral infarction in 37 (17%), and hemorrhagic infarction in 13 (6%). Hemorrhagic infarction usually occurred 20 to 30 days after aneurysmal rupture; this period corresponds with the remission stage of the vasospasm. On CT scans, the hemorrhagic infarction was revealed as a leaky hemorrhage in a low density area in 11 cases, and a massive hemorrhage with mass effect was seen in 2 cases. These findings suggest that hemorrhagic infarction after vasospasm may sometimes be fatal. Cerebral blood flow autoregulation in patients with vasospasm was normal or of a hypertensive type during the remission stage of vasospasm, when hemorrhagic infarction usually appeared. This finding shows that induced hypertension therapy is ineffective during this stage; it should be stopped by this stage because it is ineffective and also may aggravate hemorrhagic infarction.

Adult↗
PubMed1986

A role of the central catecholamine neuron in cerebral circulation.

The effect of the central catecholaminergic neurons on the cerebral microcirculation was investigated by means of a unilateral intracerebral injection of 6-hydroxydopamine (6-OHDA) which produced the degeneration of catecholamine (CA) nerve terminals. Subsequent observation with CA histofluorescence revealed an absence of CA fibers in the vicinity of the 6-OHDA injection site. A significant increase in regional cerebral blood flow (rCBF), measured by the hydrogen clearance method, was demonstrated in the CA-depleted cortex under normocapnia as compared with rCBF in the control cortex (CA-depleted cortex 47.0 +/- 2.8 ml/100 gm/min; control cortex 38.5 +/- 3.5 ml/100 gm/min; p less than 0.005). The increased rCBF in the cortex treated with 6-OHDA was suppressed by the iontophoretic replacement of noradrenaline (NA) to the CA-depleted cortex. An iontophoretic replacement of 10(-5) M dopamine (DA) mildly suppressed the increased rCBF in the 6-OHDA-treated cortex. The CO2 reactivity in the CA-depleted cortex was significantly lower than that of the control cortex (CA-depleted cortex 2.13% +/- 0.6%/mm Hg; control cortex 3.53% +/- 0.70%/mm Hg). No change was noticeable in the cerebral glucose metabolism in the CA-depleted cortex in an investigation based on tritiated (3H)-deoxyglucose uptake. It is suggested that the 6-OHDA-induced change in cerebral blood flow (CBF) is not secondary to alterations in cerebral metabolic rate, and that the central NA neuron system innervating intraparenchymal blood vessels regulates CBF through a direct vasoconstrictive effect on the cerebral blood vessels. The central DA neuron system may modulate the cerebral circulation as a mild vasoconstrictor.

Animals↗
PubMed1986

[CT-stereotaxy].

Explore the source record for details and available documents.

Brain↗
PubMed1986

[Stereotactic evacuation of hypertensive thalamic hematomas using plasminogen activator (urokinase)].

In the past five years, the authors have performed stereotactic evacuation of hypertensive thalamic hematoma using Komai's CT-stereotactic apparatus in 44 cases. Liquefied hematoma was aspirated through a stereotactic cannula, and solid hematoma difficult to aspirate was dissolved by a plasminogen activator (Urokinase) and drained out through a silastic catheter. The mean ratio of the total volume of evacuated hematoma to the estimated volume by CT image was 83.8%. The recovery from motor paresis and consciousness disturbance was observed during the early postoperative days in most patients. Functional outcome (ADL) at 3 months after operation was as follows: 24 cases (54.5%) recovered to a full or partial (self-cared) social life, 15 (34.1%) required partial care at home and 2 (4.5%) remained bedridden. Although 3 patients died within 1 month after operation, the cause of death in these patients was admitted to have no direct relation to operative procedure or to rebleeding due to the Urokinase injection. Postoperative functional prognosis was not affected by the timing of the operation. The important factors affecting ADL were preoperative neurological grade and CT classification. This stereotactic method apparently exceeded the conventional craniotomy method in the functional outcome.

Adult↗
PubMed1985

Chronic subdural hematoma after open heart surgery.

Three cases of chronic subdural hematoma after open heart surgery are reported. In all cases, computed tomography scans revealed subdural accumulations of high density after cardiac surgery. The high-density areas changed into isodensity or low density with mass effect within 2 or 3 weeks. Anticoagulant (heparin) and a tearing of bridging veins after a rapid change of the brain volume by administration of mannitol can be a cause of chronic subdural hematoma. Forty-five to 60 mL of liquefied hematoma was aspirated and the outer membrane of the hematoma cavity was recognized by a trepanation.

Adult↗
PubMed1985

Tuberous sclerosis with an atypical radiological skull change: case report.

The authors describe a case of tuberous sclerosis with atypical radiological skull change in a 8-year-old Japanese child. A plain roentgenogram showed thinning and convolution of the left occipital bone, and a cortical tuber adjacent to the thinned bone was shown by computed tomography. This kind of skull change may suggest the existence of a cortical tuber in patients with tuberous sclerosis, although this finding has not been reported previously. The mechanism of this skull change is discussed.

Child↗
PubMed1985

Chronic encapsulated intracerebral hematoma during infancy: case report.

Chronic encapsulated intracerebral hematoma is a rare condition. Only four cases have been reported. The cause of this condition is unclear. A case of chronic encapsulated intracerebral hematoma in an 1-year-old infant is reported, and the characteristic findings and their causes are discussed with a literature survey.

Cerebral Hemorrhage↗
PubMed1985

5-Hydroxytryptamine innervation of vessels in the rat cerebral cortex. Immunohistochemical findings and hydrogen clearance study of rCBF.

The role of the central 5-hydroxytryptamine (5-HT) neuron system in cerebral microcirculation of the rat was examined by immunohistochemical and hydrogen clearance methods. Immunohistochemical studies demonstrated 5-HT-immunoreactive nerve fibers along intraparenchymal blood vessels (arterioles, capillaries, and venules). Ultrastructural observation revealed that 5-HT-immunoreactive terminal boutons (0.3 to 1.0 micron in diameter) made contact with the basement membrane of the capillaries. After an intracerebral injection of 5,7-dihydroxytryptamine (5,7-DHT), a neurotoxin to the 5-HT neuron system, no 5-HT-immunoreactive nerve fibers were found around the injection site with immunohistochemical techniques. With the hydrogen clearance method, the 5,7-DHT-injected cortex showed no significant change in regional cerebral blood flow (rCBF) in the presence of normocapnia, but a significant increase in rCBF with hypercapnia, compared with the untreated cortex. These facts strongly suggest that the central 5-HT neuron system has an important role in carbon dioxide reactivity of the cerebral blood vessels.

Animals↗
PubMed1984

Monocular movement of contralateral eye following cortical stimulation in the coronal sulcus of cat.

Monocular movements of the contralateral eye were demonstrated following the stimulation of the internal kneelike portion of the cortex in the coronal sulcus of the cat. The stimulation of this cortical area in the coronal sulcus yielded rapid medial or slightly oblique ventromedial movement of the contralateral eye. While ablation of the same cortical area produced contralateral eye shift toward the dorsolateral side and the shifted eye became uncontrollable. The results suggested that the control mechanism of eye movement involves unilateral innervation system to the contralateral side as seen in the extremities.

Animals↗
PubMed1984

A light and electron microscopic immunohistochemical study of vasoactive intestinal polypeptide- and substance P-containing nerve fibers along the cerebral blood vessels: comparison with aminergic and cholinergic nerve fibers.

Vasoactive intestinal polypeptide (VIP)- and substance P-containing nerve fibers were observed in the cerebral blood vessels using an immunohistochemical technique. VIP-containing nerve fibers distributed in a spiral pattern, similar to that of muscle cells. Under electron microscopic observation, VIP-immunoreactive terminals lay close to a muscle cell in the inner layer of the adventitia. In contrast, substance P-containing nerve fibers showed a meshwork pattern in the outer layer of the adventitia. Using both acetylcholinesterase (AChE) staining and VIP immunohistochemistry, AChE-positive and VIP-immunoreactive nerve fibers revealed almost the same distribution in the same specimen. The present data suggest that VIP-containing nerve fibers may play a role in the smooth muscle control of the blood vessels, whereas substance P-containing nerve fibers may not take part in muscle control.

Animals↗
PubMed1984

Aminergic innervation of cerebral veins. Histochemical comparison with extracranial veins.

The density and distribution pattern of aminergic nerve fibers in intracranial and extracranial veins were compared by means of catecholamine histofluorescence studies. Extracranial veins (internal jugular, inferior caval, portal, renal, internal iliac, and femoral veins) showed quite a uniform distribution pattern. Large veins (jugular, caval, renal, and iliac veins) revealed a spiral pattern, and small veins presented as a meshwork (femoral vein) or in a longitudinal pattern (a branch of the femoral vein). In contrast, intracranial veins displayed more complex patterns: the dural sinus showed a longitudinal pattern and the internal cerebral vein and the superficial vein of Labbé revealed a meshwork of nerve fibers. The aminergic fibers were denser in cerebral veins (dural sinus and internal cerebral vein) than in extracranial veins. The complex distribution and the density of aminergic fibers in cerebral veins suggest that the aminergic innervation of the circulatory system may be more important in the brain than in the extracranial organs.

Amines↗
PubMed1984

[Morphological study on innervation of the cerebrospinal blood vessels. II. Spinal blood vessels].

The distribution patterns of aminergic and cholinergic nerve fibers in the feline spinal blood vessels were studied by means of amine histofluorescence and acetylcholinesterase (AChE) staining. The anterior spinal artery had a dense network of aminergic and AChE-positive (probably cholinergic) nerve fibers. The posterior spinal vein, in contrast, had only aminergic nerve fibers. Intraparenchymal small blood vessels in the spinal cord also had strongly fluorescent (probably peripheral) aminergic nerve fibers. This was quite a characteristic feature in the spinal cord. The distribution pattern and the density of these two sorts of nerve fibers widely varied with the individual segment of the spinal cord. The thoracic spinal cord had the lowest number of these nerve fibers throughout the spinal cord. This fact may give a clue to explain why the thoracic spinal cord is most susceptible to ischemic change.

Acetylcholinesterase↗
PubMed1984

[Peptidergic innervation of the cerebral blood vessels--an immunohistochemical study].

By an immunohistochemical technique, vasoactive polypeptide (VIP)-and substance P-containing nerve fibers are observed in the cerebral blood vessels. VIP-containing nerve fibers distribute in a spiral pattern, similar to the muscle cell distribution pattern. Under an electron microscopic observation, VIP-immunoreactive terminals lie just near to a muscle cell in the inner layer of the adventitia. In contrast, substance P-containing nerve fibers show a meshwork pattern in the outer layer of the adventitia. In combination of acetylcholinesterase (AChE) staining and VIP immunohistochemistry, AChE-positive and VIP-immunoreactive nerve fibers reveal almost same distribution in the same specimen. The present data suggest that VIP-containing nerve fibers may play a role of smooth muscle control of the blood vessels, while substance P-containing nerve fibers may not take part in muscle control.

Animals↗