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Biomedical subjects

N Komai

Publications and source records attributed to N Komai.

At least 55 records · Page 3Linked to original sources
PubMed1994

Development of acquired arteriovenous fistulas in rats due to venous hypertension.

Dural sinus thrombosis has been hypothesized as a possible cause of dural arteriovenous fistulas (AVF's). The pathogenesis and evolution from thrombosis to actual development of an AVF are still unknown. To study dural fistula formation, a surgically induced venous hypertension model in rats was created by producing an arteriovenous shunt between the carotid artery and the external jugular vein. The external jugular vein beyond the anastomosis was ligated 2 to 3 months after surgery and angiography was performed to identify any new acquired AVF's. Forty-six male Sprague-Dawley rats, each weighing approximately 300 gm, were used for this study. In Group I, 22 rats underwent a common carotid artery anastomosis to the external jugular vein, which is the largest draining vein from the transverse sinus via the posterior facial vein, followed by proximal external jugular vein ligation. In Group II, 13 rats underwent the same surgical procedure, followed by contralateral posterior facial vein occlusion. Group III served as the control group, in which 11 rats underwent only unilateral external jugular vein occlusion with or without contralateral posterior facial vein occlusion. The shunts in Groups I and II were ligated at 2 to 3 months following surgery, and transfemoral angiography was performed immediately before and after occlusion. New acquired AVF's had developed in three rats (13.6%) in Group I, three rats (23.1%) in Group II, and no rats (0%) in Group III. One of these newly formed fistulas was located at the dural sinus, analogous to the human dural AVF. The other five were located in the subcutaneous tissue, including the face and neck. The dural AVF in the rat was present on follow-up angiography at 1 week after the bypass occlusion. It is concluded that chronic venous hypertension of 2 to 3 months' duration, without associated venous or sinus thrombosis, can induce new AVF's affecting the dural sinuses or the subcutaneous tissue.

Animals↗
PubMed1994

[Histological analysis of craniopharyngiomas--with special reference to their histological origin and differentiation].

The histogenesis of craniopharyngiomas was immunohistochemically studied on the basis of cytokeratins (CK) expression, with special reference to histological subtype, i.e., the squamous type (Sq) and adamantinomatous type (Ad). Alcian-Blue staining and immunohistochemical expression of secretory component were also studied to assess secretory activity. Although combined expression of simple-, stratified-, and skin-type CK was detected in both Sq and Ad, the pattern of expression in Sq and Ad was different. Sq displayed epidermal differentiation of CK, and secretory activity was limited to the apical cells of Sq. Based on these findings, the histogenesis of Sq appeared to be from Rathke's pouch, but that of Ad remained obscure.

Adolescent↗
PubMed1994

[Transcortical sensory aphasia in a patient with metastatic brain tumor in the left frontal lobe].

We reported a case of a 62-year-old right-handed woman who had transcortical sensory aphasia caused by a metastatic brain tumor in the left frontal lobe. She had mild right hemiparesis involving the face, without hyperactive tendon reflexes. She had neither sensory disturbance nor other cranial nerve deficits. Her spontaneous speech was fluent, and she sometimes had echolalia. Her object naming, word fluency, verbal comprehension and writing were severely disturbed. This contrasted with full preservation of repetition of phonemes and short sentences. Reading of words was preserved. CT scan revealed a subcortical lesion in the left superior frontal gyrus. Gd-enhanced MRI showed a ring-enhanced mass lesion in the frontal lobe outside of Broca's area. We thereby concluded that transcortical sensory aphasia may be caused by frontal lobe lesion independent of the perisylvian speech areas.

Adenocarcinoma, Papillary↗
PubMed1994

Clinicopathological study of lymphomas in the central nervous system--with the reference to the recurrence and proliferative activity.

Nine cases of CNS lymphomas obtained by surgical resection or biopsy between 1984 and 1991 were examined. One case of intraorbital lymphoma was also studied. All patients underwent radiotherapy. In addition, 7 underwent steroid therapy and 4 underwent chemotherapy. The case comprised the following (LSG classification): small cell type (3), medium cell type (1), large cell type (3), and medium and large cell type (3). Immunohistochemically, LCA and B-26 immunopositivity were seen in all cases. Cytoplasmic Ig immunopositivity was observed in five cases. The mean AgNORs number was 4.63 (range: 1.8-7.2). The mean PCNA SI was 26.75 (range: 10.2-39.7). No correlation was found between LSG classification and proliferative activity. Although no correlation was found between AgNORs number and recurrence, the recurrent group showed tendency to have more AgNORs that the non-recurrent group. Although no correlation was found between PCNA SI and recurrence, the recurrent group showed tendency to have a higher PCNA SI than the non-recurrent group. The proliferative activity in AgNORs and PCNA studies may be considered as a prognostic indicator in CNS lymphomas.

Adult↗
PubMed1994

Cellular differentiation, secretory and proliferative activities of craniopharyngiomas.

The cellular differentiation of craniopharyngiomas was studied immunohistochemically by determining the expression of cytokeratins. Alcian-Blue staining was used to assess secretory activity and expression of AgNORs and PCNA as indicators of proliferative activity. Both, tumors of the adamantinomatous type and of the squamous type expressed complex type cytokeratins, with skin type differentiation being noted in some cases. In addition, epidermal differentiation of cytokeratins was found in the squamous types. Intracellular Alcian-Blue staining was limited to apical cells of tumors of the squamous type. Neither AgNORs staining nor PCNA staining proved statistically significant results with respect to the histological type of tumor or patient's age. However, PCNA staining was predominantly noted in basal cells of the squamous type tumors. Although their ultimate significance remains to be established, the results presented provide additional evidence with regard to the possible origin of both craniopharyngioma types, and suggest the potential value of some of the parameters studied as prognostic indicators.

Adolescent↗
PubMed1994

Computed topographic electroencephalographic study in left hemiplegic patients with higher cortical dysfunction.

Computed topographic electroencephalography (EEG) was performed on patients with right hemispheric injury due to cerebral infarction to investigate the relationship of wave form pattern with neurologic and neuropsychologic data and activities of daily living (ADL). Neurologic signs, unilateral spatial neglect, motor impersistence, and constructional apraxia were found to have no relation to the wave form pattern of computed topographic EEG. In patients with abnormalities detected by the "Mini-Mental State" examination (MMSE) or the "Kanahiroi" test, and in patients with abnormalities in word fluency, extensive slowing of EEG frequency was commonly observed ipsilateral to the side of the lesion or bilaterally, and the ADL were frequently poor. In contrast, among the patients with slow waves and retained alpha waves, the MMSE, "Kana-hiroi" test, word fluency, and ADL were less abnormal. Computed topographic EEG may thus be a useful tool to evaluate neuropsychological status in rehabilitation patients with cerebral infarction.

Activities of Daily Living↗
PubMed1993

A case of vessel perforation during interventional neuroradiological procedure. Operative findings of the perforated vessel.

A case of vessel perforation by a guide wire during an interventional neuroradiological procedure is reported. The patient was a 59-year-old woman with a left frontal basal arteriovenous malformation (AVM) fed by the left anterior cerebral artery. Transarterial embolization of the AVM was attempted. During the procedure, vessel perforation by the guide wire occurred at the left A1-A2 junction and resulted in subarachnoid hemorrhage, which stopped spontaneously. The patient developed progressive obstructive hydrocephalus, and surgical treatment was performed. The AVM was totally removed after ventricular drainage, and the arterial perforation site was explored. When clot around the left A1-A2 junction was removed, hemorrhage recurred. This hemorrhage was similar to what has been observed when a small perforating artery was avulsed. The hemorrhage site was coagulated under temporary occlusion of both A1 segments. Surgical intervention was probably not necessary for this type of bleeding if it had stopped spontaneously, because the rebleeding from the small pinhole would be unlikely, and the operation was more hazardous than the usual aneurysmal surgery.

Cerebral Arteries↗
PubMed1993

Complex occipital arteriovenous fistula associated with neurofibromatosis treated by embolization and surgery. Case report.

It is well known that neurofibromatosis is associated with various types of arteriovenous fistulas (AVF), but association with an occipital AVF has not been reported. We are reporting this case which was successfully treated with a combination of embolization and surgery. Superselective angiography defines the anatomic details of the fistula and intraoperative digital subtraction angiography (DSA) facilitates the surgery to cure the fistula. It is important to identify the best therapeutic options using angiographic information to treat a complex arteriovenous fistula.

Adult↗
PubMed1993

Percutaneous transluminal angioplasty for the M2 portion vasospasm following SAH: development of the new microballoon and report of cases.

A new silicone microballoon was developed for the percutaneous transluminal angioplasty of smaller intracranial vessels, such as A1, A2 and M2. This balloon was 0.5 x 2.0 mm in the deflated condition and became 2.2 x 6.5 mm inflated with 0.02 mL of fluid, and its bursting pressure was 2 atm. Two illustrative cases are presented. The first case was not treated in the M2 distribution. The second case of vasospasm of the left M2 portion was successfully treated with this new balloon, with prompt improvement of the neurological condition and cerebral circulation. The usefulness of our microballoon in treating a patient with vasospasm of small intracranial arteries is discussed.

Angioplasty, Balloon↗
PubMed1993

Cerebral blood flow in mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes.

BACKGROUND AND PURPOSE: The precise mechanism of neurological symptoms with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) is still controversial. We investigated the correlation between strokelike episodes and cerebral blood flow in two patients with MELAS and discuss the pathogenesis of strokelike episodes with MELAS. SUMMARY OF REPORT: Cerebral dynamic computed tomography and cerebral angiography were used to measure cerebral circulation in the first case, that of a 20-year-old woman with MELAS. The second subject was a 13-year-old female who was studied with xenon-enhanced computed tomography. The cerebral blood flow studies were performed 3-72 hours after the onset of strokelike episodes. Serial cerebral angiography, dynamic computed tomography, and xenon-enhanced computed tomography showed vasodilation localized in the affected cerebral cortexes during strokelike episodes, without any reduction in regional cerebral blood flow. CONCLUSIONS: Our study suggests that the strokelike episodes associated with MELAS are different in origin from ischemic stroke.

Adolescent↗
PubMed1993

Influence of regional cerebral blood flow on event-related potential (P300).

The relationships between event-related potential (P300), higher brain functions, and regional cerebral blood flow (rCBF) were examined in 31 neurosurgical patients. The P300 latency, evaluated by an acoustic "odd-ball" paradigm, was normal in 14 and prolonged in 17 patients. Fourteen of 17 prolonged P300 patients had reduced rCBF in the right cerebral hemisphere, especially the frontal lobe and/or thalamus. There was a significant inverse relationship between P300 latency and laterality index (rt rCBF/lt rCBF) in the frontal lobe. Prolonged P300 patients revealed significant abnormalities in psychological tests compared to normal P300 patients. There were significant inverse relationships between the P300 latency and "orientation" and "memory" test scores. Decreased rCBF in the right cerebral hemisphere, especially the frontal lobe and/or thalamus, is associated with prolonged P300 latency, suggesting that the right cerebral hemisphere is important in human cognitive processes.

Adult↗
PubMed1993

Acute subdural hematoma associated with vacuolated meningioma--case report.

A 67-year-old male presented with a left temporal convexity vacuolated meningioma associated with acute subdural hematoma manifesting as sudden headache, nausea, and vomiting without neurological deficit. Magnetic resonance imaging disclosed an extra-axial mass as mixed low- and high-signal intensities and a crescent high-intensity area in the left convexity. Histological examination diagnosed meningotheliomatous meningioma with vacuolated components and hemorrhagic foci. The tumor and hematoma were removed without postoperative complications.

Aged↗
PubMed1993

Cytokeratin immunohistochemical study of epithelial cysts in the central nervous system: with special reference to origins of colloid cyst of the third ventricle and Rathke's cleft cyst in the sella.

A variety of epithelial cysts in the central nervous system were examined immunohistochemically for expression of cytokeratins. Colloid cysts, Rathke's cleft cysts and epithelial cysts in the spinal canal expressed complex type cytokeratins, while enterogenous cysts and neuroectodermal cysts showed only simple type cytokeratins. Colloid cysts showed a pattern of cytokeratins similar to that of upper respiratory tract which is endodermal in origin. In contrast, Rathke's cleft cysts showed a pattern of cytokeratins similar to that of the adenohypophysis and salivary gland which are ectodermal in origin. The CK immunohistochemical studies are discussed with regards to diagnostic significance and origins of their cysts.

Adult↗
PubMed1993

[A case of chronic progressive external ophthalmoplegia with pituitary hypothyroidism].

We report a case of chronic progressive external ophthalmoplegia with pituitary hypothyroidism. This patient had complained of hearing-loss at the age of fourteen and loss of body weight at fifteen. She was examined by otorhinolaryngologists at large hospitals yearly over a period of 5-6 years, but hearing-loss remained unknown. As her ophthalmoplegia progressed (as is evident from family photographs from the age of sixteen onward), with hindsight it should have been recognized. When examined on October 11, 1991, she complained of ptosis, speech disturbance and dysphagia at the age of thirty-four. Neurological examination revealed limitation of ocular movement, bilateral ophthalmoplegia, facial muscle atrophy, and weak gag reflex. She showed muscle atrophy in her neck including both sternocleidomastoid, major and minor rhomboid, girdle and distal parts of upper and lower extremities. Muscle biopsy of her biceps demonstrated ragged-red fibers, cytochrome c oxidase (CCO) deficient fibers and deletion of mitochondrial DNA. A plain CT scan revealed bilateral periventricular lucency, and a brain MR image showed a normal sized pituitary gland but diffuse high-signal intensities in the both periventricular white matter with proton density weighted and T2-weighted axial MR image. And also her electroencephalogram showed diffuse 7 Hz slow waves in all areas and increased slow waves by hyperventilation, and all waves from I to V of the auditory brain stem response disappeared. The effect of TRH on serum TSH secretion was not evident in this patient. This case was ascertained to be chronic progressive external ophthalmoplegia with pituitary hypothyroid function.

Adult↗
PubMed1993

[A case of epidural hematoma caused by a vacuum extraction without any skull fractures and accompanied by cephalohematoma].

A case of epidural hematoma associated with cephalohematoma caused by a vacuum extraction was reported. Old liquefied hematoma was removed via a small burr hole in the parietal bone at the age of 23 days. No neurological deficits were recognized at the age of 6 months. As the dura mater does not easily detach from the overlying skull in the neonate, it is a very rare occurrence for this to happen as a complication of the use of forceps or in extractions. To our knowledge, only 4 cases of epidural hematoma after vacuum extraction have been reported. The mechanism of the development of an acute epidural hematoma during extraction is reported to be due to direct force to the dura mater and skull induced by negative pressure of a vacuum extraction. In the present case, it seems that negative pressure produced a detachment of the dura mater from the overlying skull. It suggests that examinations including plain craniogram and CT scan should be performed as soon as possible in the neonate with cephalohematoma when they have been delivered by a vacuum extraction.

Bone Diseases↗
PubMed1993

[Surgical treatment of Parkinson's disease].

Surgical treatment for Parkinson's disease began by blocking of the pyramidal system in early part of this era. In 1942, Meyers performed Ansotomy for the treatment of Parkinsonism without leaving hemiplegia, leading subsequent operating target to blocking of pallidofugal fiber. Then, the development of stereotaxy in 1947 caused an operative progress to Pallidotomy and further to Thalamotomy. Although the spread of levodopa therapy gradually brought about decline of surgical treatment, Thalamotomy became to be reexamined in view of not a little problems about and side effects of levodopa therapy. With the development of CT, MRI and the like, Thalamotomy via MRI-stereotaxy was developed, making operations safer and surer. Besides, transplantation of dopamine neurons into the striatum was tried as an essential treatment and is in clinical application via animal experiments. Fetal ventral mesencephalic tissue and adrenal medullary tissue are available therefore, but demerits are such that the former poses some ethical problem and the latter is poor and short-lived response. The transplantation of stellate ganglion into the striatum, which we have recently developed is safe and more effective than the adrenal medullary tissue. The respective one thirds of the cases did without levodopa following transplantation, needed half as much as the preoperative levodopa dose and needed the same as the latter. Although Horner's syndrome was noted in all cases following transplantation, no Parkinson syndrome became aggravated in any one of the cases.

Adrenal Medulla↗