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Biomedical subjects

N Komai

Publications and source records attributed to N Komai.

At least 91 records · Page 5Linked to original sources
PubMed1991

[Acute subdural empyema due to peptostreptococcus].

A very rare case of acute subdural empyema due to peptostreptococcus was reported. A 11-year-old-girl was admitted to our hospital with high grade fever, unconsciousness and rt hemiparesis. CT scans showed the mass effect caused by the subdural empyema over the left frontotemporal region. Subdural empyema was evacuated by the craniotomy. Peptostreptococcus was found in the pus obtained during the operation. However, CT scans 10 days after the operation revealed another subdural empyema in the left frontal base and interhemispheric fissure, which was removed again by the craniotomy using coronal incision 14 days after the first operation. Frontal sinusitis was also demonstrated by CT scan. Killian's operation to the frontal sinusitis was performed by otorhinolaryngologists at the same time. Six weeks after the second operation, she was discharged without any neurological deficits. Peptostreptococcus is one of the indigenous microflora of the oral cavity, skin, gastrointestinal tract and genitourinary system and may be a causative microorganism in every type of human infection due to its abnormal localization. There is a controversy concerning surgical management subdural empyema. Both the burr hole drainage of pus and the craniotomy are advocated. Associated otorhinologic lesions must not be overlooked. Otorhinologic consultation should immediately be obtained so that the drainage of an infected paranasal or mastoid sinus can be performed at the time of craniotomy. This is critical to prevent the recurrence of the subdural empyema from further extension of the extracranial disease.

Acute Disease↗
PubMed1991

[Selective vulnerability of peptide-containing neurons in cerebral ischemia; immunohistochemical study].

Histochemical changes in peptidergic and catecholaminergic neurons during ischemia were investigated in the cerebral neocortex of the gerbil. Catecholaminergic fibers were observed by catecholamine histofluorescence with glyoxylic acid solution, and peptidergic neuron systems such as vasoactive intestinal polypeptide (VIP), somatostatin (SOM), and neuropeptide Y (NPY) were observed by immunohistochemistry. Two hours after unilateral occlusion of the internal carotid artery, catecholaminergic fibers disappeared in the neocortex on the occlusion side, while peptidergic nerve fibers except for NPY fibers were intact after 2 hours of ischemia. NPY fibers had decreased in number on the occlusion side 2 hours after ischemia. VIP-, SOM-, and NPY-immunoreactive neurons showed a decrease of 60% six hours after ischemia, and these neurons completely disappeared in the cerebral neocortex 24 hours after ischemia. These results suggest that catecholaminergic neuron system is more vulnerable than the peptidergic one in ischemic event.

Animals↗
PubMed1991

[Dynamics of extracellular acetylcholine of the gerbil striatum during cerebral ischemia monitored by intracerebral microdialysis].

Neurons in the hippocampus and striatum are vulnerable to the ischemic insult. In the present study we focused on the vulnerability of acetylcholine (ACh)-containing neurons in the striatum. To determine the change of ACh content in the striatum, we employed a simple sensitive brain microdialysis method with high performance liquid chromatography electrochemical detection. Morphological change of cholinergic neurons was studied by ACh-esterase staining during ischemic insult. After bilateral carotid artery occlusion, local cerebral flow decreased less than 5 ml/min/100 g in the striatum. Ach content in dialysate for 20 min after the occlusion was elevated to 135% of the control. ACh content decreased to 15% of the control 2hs after the ischemia. Density of Cholinergic fibers and cell bodies was reduced 10 min after the ischemia and further decreased 20 min after the occlusion. Our study suggests that the transient elevation of ACh content was probably due to diffusion of ACh from destruction cholinergic terminals after the ischemic insult. The increase of ACh immediately after arterial occlusion may affect severity of ischemic damage in the brain by its excitatory effect.

Acetylcholine↗
PubMed1990

Effect of atrial natriuretic peptide on ischaemic brain oedema.

We investigated the effect of intraventricularly administered atrial natriuretic peptide (ANP) on the brain water, sodium and potassium contents in ischaemic brain oedema. Global ischaemia (15 min) followed by recirculation (30 min) produced by a three vessel occlusion in the rat served as a model for induction of ischaemic cerebral oedema. Water content was measured by a drying-weighing method. Sodium and potassium contents were measured by means of flame photometry. The effect of ANP was evaluated by comparing these parameters of the ANP-treated group (5 micrograms/kg and 10 micrograms/kg atriopeptin) with those of the control group (administration of 0.9% NaCL). ANP did not significantly change the content of water, sodium and potassium in the preischaemic or ischaemic brain. Intraventricularly administered ANP (5 micrograms/kg and 10 micrograms/kg) caused significant decrease in the brain water (p less than 0.02) and sodium (p less than 0.01) contents after 15 min of ischaemia and 30 min of recirculation, while the brain potassium content remained unaltered. Serum osmolality, and sodium and potassium concentrations were not influenced by administration of ANP. Accordingly, ANP acts directly on the central nervous system to inhibit brain water and sodium accumulation in ischaemic brain oedema.

Animals↗
PubMed1990

Assessment of risk of carotid occlusion with balloon Matas testing and dynamic computed tomography.

Temporary occlusion of the internal carotid artery with a balloon catheter (balloon Matas test) and simultaneous dynamic computerized tomography scanning (DCT) were performed to determine the tolerance of permanent carotid occlusion in eight cerebral aneurysm and two carotid-cavernous fistula (CCF) cases, in whom internal carotid occlusion might be necessary during operation or as a choice of treatment. All patients were evaluated by mean transit time (MTT), especially % transit time (MTT of the occluded side x 100/MTT of the control side). In six patients, % transit time (%TT) was less than 155 and no neurological signs appeared after permanent internal carotid occlusion. Neurological deficit appeared when mean arterial blood pressure was 80, and disappeared when mean arterial blood pressure was 100 during the balloon Matas test in a case whose %TT was 200. Neurological deficit appeared several seconds after the balloon Matas test in a case whose %TT was 250. The critical %TT value to cause symptomatic ischaemia was 200 from our results. Therefore, it is necessary to undertake treatment such as bypass surgery for the patients whose %TT is near 200, even if the balloon Matas test was negative.

Aged↗
PubMed1990

Effect of atrial natriuretic peptide on ischemic brain edema: changes in brain water and electrolytes.

The effects of intraventricularly administered atrial natriuretic peptide (ANP) on the brain water, sodium, and potassium contents in ischemic brain edema were investigated. By use of a three-vessel occlusion model, ischemic brain edema was produced in the rat brain by 15 minutes of global ischemia followed by recirculation. Water content was measured by means of a drying/weighing method; sodium and potassium contents were measured by means of flame photometry. The effects of intraventricular administration of ANP were evaluated by a comparison between the groups given 2 and 5 micrograms of atriopeptin II (treated) and those given 0.9% NaCl (sham-treated). The treated groups showed significant decreases in brain water (P less than 0.02) and sodium (P less than 0.01) contents at 15 and 30 minutes after recirculation, whereas the brain potassium contents remained unaltered. Before ischemia and immediately after 15 minutes of ischemia, intraventricularly administered ANP did not significantly change the brain water, sodium, or potassium contents. There was no significant difference in the effect on the amount of brain water and sodium between the two doses (2 and 5 micrograms). These effects of ANP were thought not to be mediated by primary changes in serum osmolality and sodium and potassium concentrations, because intraventricular administration of ANP did not change them significantly. The present results reveal that, in ischemic brain edema, ANP may act directly on the central nervous system to inhibit brain water and sodium accumulation.

Animals↗
PubMed1990

Transplantation of autologous superior cervical ganglion into the brain of parkinsonian monkeys.

Autologous transplantation of the superior cervical ganglion (SCG) into the caudate nuclei of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonian monkey was studied in regard to animal behavior and catecholamine (CA) metabolites in cerebrospinal fluid. Monkeys which had undergone autotransplantation of the SCG revealed an apparent improvement in motor activity. The homovanillic acid content in cerebrospinal fluid increased following the SCG transplantation and was correlated with an increase in motor activity. CA histofluorescence studies confirmed the long-term survival of the SCG graft in which many CA fibers and cells were observed. The present experiment indicates that dopamine released from the graft improved the symptoms of parkinsonism in the monkey.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1990

Transplantation of peripheral cholinergic neurons into Alzheimer model rat brain.

The effect of transplantation of peripheral cholinergic neurons was examined in rats with a lesion of the nucleus basalis Meynert (NBM). The rats with an NBM lesion showed abnormal increase of spontaneous activity, disturbance of memory retention, and disturbance of learning acquisition. In contrast, the rats which had received transplantation of cholinergic neurons into the cerebral cortex displayed amelioration of abnormal behavior produced by the destruction of the NBM. Morphological study (acetylcholinesterase) clearly showed survival of many transplanted cholinergic cells. The present study suggests that autotransplantation of peripheral cholinergic cells may be a possible therapy for Alzheimer's disease.

Acetylcholinesterase↗
PubMed1990

Stereotactic hyperthermia for brain tumors.

We have developed a localized hyperthermia system using computed tomography-stereotactic surgery as malignant brain tumor therapy. In an experimental study, the temperature in the area of the cat brain within 20 mm from a radiofrequency electrode reached more than 43.7 degrees C. Intravenous administration of MCNU during hyperthermia caused a significant increase of MCNU content in the heated brain as compared with a control brain. In the clinical study, localized radiofrequent hyperthermia using stereotactic surgery was performed on 7 malignant deep-seated gliomas and 21 metastatic brain tumors. Especially, combination therapy of stereotactic hyperthermia and chemotherapy was effective treatment for gliomas less than 30 mm deep in the brain.

Adolescent↗
PubMed1990

Autologous transplantation of the superior cervical ganglion into the brain of parkinsonian monkeys.

The effect of autologous transplantation of the superior cervical ganglion (SCG) into the brain of parkinsonian monkeys was studied through quantitative measurement of animal behavior. The motor activity of the monkey was measured with a telemetry system during the experiment. After experimental parkinsonism was induced by repeated intravenous injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), three monkeys were treated with autologous transplantation of the SCG into both caudate nuclei. One monkey served as a control without SCG transplantation after MPTP treatment. Three SCG-transplanted monkeys showed biphasic (acute and chronic) behavioral amelioration of parkinsonism after transplantation. In the acute stage, the animals showed transient hyperkinesia with aggressive behavior and loss of circadian rhythm. In the chronic stage following acute hyperkinesia, the animals regained normal behavior and circadian rhythm without aggressiveness. In contrast with the transplanted monkeys, the control monkey failed to show recovery of the bradykinesia and muscle rigidity.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1990

[Epithelial cyst in the central nervous system--characteristic expression of cytokeratin].

Twenty one cases of epithelial cysts in the central nervous system including six colloid cysts of the third ventricle, eight Rathke's cleft cysts in the sella, two enterogenous cysts in the posterior fossa, two epithelial cysts in the spinal canal and three neuroectodermal cysts in the cerebrum were examined immunohistochemically for expression of intermediate filamentous proteins-simple type, stratified type and skin type cytokeratins and GFAP. Colloid cysts of the third ventricle. Rathke's cleft cysts in the sella and epithelial cysts in the spinal canal expressed complexed type cytokeratins while enterogenous cysts and neuroectodermal cysts showed only simple type cytokeratins. In addition, several Rathke's cleft cysts demonstrated skin type differentiation and expressed GFAP in occasional lining cells. The characteristic composition and distribution of cytokeratins in various kinds of epithelial cysts in the central nervous system are demonstrated and discussed with regards to their origins.

Adult↗
PubMed1990

[Cervical spinal epidural abscess: case report].

Most cases of spinal epidural abscesses occur in a midthoracic or lower lumbar location. Cervical spinal epidural abscess is distinctly rare, and its prognosis is not favorable due to respiratory problems. We report a case of cervical spinal epidural abscess. A 77-year-old male was admitted because of tetraparesis and dyspnea. Two months before admission, he had been treated by femoro-femoral bypass for arteriosclerosis obliterans , and he had suffered from postoperative wound infection one month later. He had noticed neck pain two days before admission, followed by a numbness and motor weakness in both hands. Neurological examination showed flaccid tetraplegy with an absence of DTRs, paralysis of intercostal muscles, loss of sensation below the C4 dermatome, and bladder dysfunction. A spinal CT scan revealed a mass lesion in the anterior epidural space from C2 to C6, which displaced the spinal cord posteriorly. A myelogram showed complete blockage of contrast medium at the level of C7-T1. He was treated by emergency laminectomy of C3 to C6 with evacuation of the epidural abscess. Culture showed staphylococcus aureus, for which appropriate antibiotics were administered. In spite of such an intensive treatment, the patient showed poor neurological improvement and died 42 days after operation.

Abscess↗
PubMed1989

Non-Hodgkin's lymphoma involving the brain. Diagnostic usefulness of stereotactic needle biopsy in combination with paraffin-section immunohistochemistry.

A stereotactic needle biopsy was examined for applicability in diagnosing brain non-Hodgkin's lymphoma (NHL), because the procedure is far less aggressive than biopsy by open surgery. Formalin-fixed materials including four stereotactic specimens were available from nine patients with brain NHL. In addition to routine histopathology and histochemistry, paraffin-section immunohistochemistry was performed using a panel of monoclonal antibodies suited to such sections. Although several histopathological features characteristic of brain NHL could not be evaluated in three of the four stereotactic specimens owing to the small size of the specimens and partial invasion by lymphoma cells, the lesions in all cases could be characterised by immunohistochemistry. Examination for cytoplasmic immunoglobulin (cIg) was also performed, but specific identification of cIg was difficult in five cases because of diffuse background staining and passive diffusion of plasma protein into the cells during tissue processing. A review of the literature indicates the technical difficulty in cIg staining, since the incidence of cIg-positive cases in an individual study varied considerably, and lymphoma cells in 15 of 128 cIg-positive brain NHL cases have been reported to possess both light chains. From these findings, together with the relative difficulty in obtaining fresh tissues for study, it is concluded that, when the specimens are to be examined by paraffin-section immunohistochemistry using the above monoclonal antibodies, stereotactic needle biopsy is a useful, less aggressive method for diagnosing brain NHL.

Adult↗
PubMed1989

Cystic arteriovenous malformation. A case report.

The authors report on a rare case of arteriovenous malformation (AVM) associated with cyst formation. Only five similar cases have been reported. CT findings of the cyst are divided into two types: 1) slit-like low density and 2) round one. Three patients showing slit-like cysts had experienced sudden severe headaches, probably due to haemorrhage. In contrast, two patients showing round cystic lesions had not experienced such sudden headaches and they revealed a nodule in the cyst at surgery. These facts suggest that there may be two different mechanisms for cyst formation in AVM's: haemorrhage and exudation. Slit-like cysts may result from old haemorrhage from the AVM nidus. Round cystic lesions may be due to exudation from the AVM nidus.

Adult↗
PubMed1989

[Arteriovenous malformation associated with cyst. Case report].

The authors present the fifth reported case of arteriovenous malformation (AVM) associated with cyst formation. Among these five cases, computed tomography has demonstrated two types of cyst: round, and slit-like with low density. The three patients with slit-like cysts experienced sudden, severe headache, probably due to hemorrhage. The two patients with round cystic lesions did not have sudden headache, and at surgery the cysts were found to contain a mural nodule. These facts suggest that there may be two different mechanisms of cyst formation in the vicinity of an AVM: hemorrhage (slit-like cysts) and exudation (round cysts).

Adult↗
PubMed1989

[Osteoblastic skull metastasis of lung cancer].

A case of osteoblastic skull metastasis of lung cancer is reported. A 56-year-old female patient was admitted to our hospital with complaints of headache and tumor of the right parietal bone. A plain skull X-ray showed hyperostotic feature of the right parietal bone. CT scan displayed that right parietal bone became thick and osteoblastic. Soft tissue was shown in the hyperostotic bone under MRI. An external carotid angiogram showed that the skull tumor was fed by the middle meningeal artery. The skull tumor and 2 solid intracerebral tumors were extirpated. Histological examination revealed adenocarcinoma in the skull and intracerebral lesions. The present case indicates that osteoblastic stimulating factor may be secreted by lung cancer.

Adenocarcinoma↗
PubMed1989

Stereotactic evacuation of hypertensive cerebellar hemorrhage using plasminogen activator.

Treatment for hypertensive cerebellar hemorrhage still remains controversial as to whether direct surgical procedure is indicated or not. This is so even after the introduction of CT scan which easily demonstrates the location and size of the hematoma and the presence of hydrocephalus. In this paper, we present our experience of 20 patients with cerebellar hemorrhage treated by stereotactic evacuation using Komai's CT-stereotactic apparatus. All the patients had vertigo, cerebellar symptoms, dysfunction of brain stem or consciousness disturbance. The hematomas on CT scan were more than 28 mm in diameter. Acute obstructive hydrocephalus occurred in 90% of the patients with hematoma 40 mm or larger in size. The patients with consciousness disturbance were immediately operated on after the attack, and a drainage tube was placed in the hematoma cavity to drain cerebrospinal fluid and liquefied hematoma for one to eight days. On the other hand, when patients with hematoma around 30 mm in diameter complained vertigo for about two weeks, they also were operated on stereotactically. After the operation, their symptoms improved rapidly. The stereotactic operation could aspirate about 85% of the estimated hematoma volume and improved the hydrocephalus, except in one case in which the patient rapidly deteriorated to coma level with a large cerebellar hemorrhage and brain stem damage. This stereotactic evacuation of cerebellar hematoma using a plasminogen activator is effective for not only the removal of hematoma, but also for the treatment of secondary hydrocephalus following obstruction of the fourth ventricle by cerebellar hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗