Biomedical subjects

N Komai

Publications and source records attributed to N Komai.

At least 73 records · Page 4Linked to original sources

PubMed1993

[Newly developed blocking balloon catheter for PTA of internal carotid artery].

We have developed a new blocking balloon system for percutaneous transluminal angioplasty (PTA) of the internal carotid artery (ICA). A latex balloon (BALT) is attached on the top of a Superselector infusion-type catheter (TORAY) which is used as a blocking balloon catheter. It can be navigated into the distal part of the ICA under torque control as well as flow control by withdrawing the core wire. Our PTA procedure is as follows, 1) insert the sheath catheter 8-9 F in size, 2) insert the PTA balloon catheter (Accent balloon, Cook) with a blocking balloon catheter through the sheath catheter, 3) navigate the blocking balloon into the distal part of the ICA, 4) introduce the PTA balloon to the stenotic portion after occlusion of the distal ICA by the blocking balloon, 5) PTA, 6) wash the lumen of the ICA with saline, 7) deflate the blocking balloon and withdraw the system. We performed PTA for 5 ICA lesions in 4 cases and got successful dilatations for all of them without complications. Our blocking balloon system is useful for performing the PTA of the ICA safely.

Aged↗

PubMed1992

The recurrence of primary intracranial germinomas. Special reference to germinoma with STGC (syncytiotrophoblastic giant cell).

Twenty three cases of primary intracranial germinomas including five cases of germinomas with syncytiotrophoblastic giant cells are studied and analyzed, with special reference to the recurrence under radiotherapy. The follow-up period for all cases was 7 months to 12 years (average: 5.8 years) with that for pure germinomas ranging from 8 months to 12 years (average: 5.7 years) and that for germinomas with syncytiotrophoblastic giant cells ranging from 7 months to 11 years (average: 6.3 years). Late recurrence was observed in three cases (3/23, 13%), developing outside of the initial irradiation field. With regard to recurrence, significant correlation to radiation fields was evident, while it was not to radiation doses. Furthermore, germinoma with syncytiotrophoblastic giant cells showed a more significant tendency to recur than pure germinoma. The radiotherapy of germinomas is discussed and the clinical features of germinoma with syncytiotrophoblastic giant cells are presented.

Adolescent↗

PubMed1992

MRI changes in embolized meningiomas.

Study of the MRI changes that occur after superselective embolization of hypervascular meningiomas with Gelfoam powder (5 cases) and polyvinyl alcohol (PVA) particles 150-250 microns in size (4 cases) has indicated that, after embolization, meningiomas showed loss of the signal void, decrease in gadolinium-DTPA contrast enhancement, and prolonged T1 and T2. Shortening of T1 and T2 was seen in two patients with Gelfoam-embolized meningiomas in whom CT showed pooling of iodinated contrast medium in the tissue. In vitro experimental data demonstrated that the shortening of T1 and T2 was due to the iodinated contrast medium.

Aged↗

PubMed1992

A method for quantitative measurement of cerebral vascular permeability using X-ray CT and iodinated contrast medium.

Cerebral vascular permeability is an important consideration in treatment for intracranial tumours. We have developed a new method to measure the cerebral vascular permeability quantitatively using a conventional X-ray CT scanner and iodinated contrast medium. We have already applied our method in 50 cases of intracranial tumour and 5 cases, which establish the methodology, are demonstrated. Dynamic CT scanning of a section including the tumour and the superior sagittal sinus was performed over 40 min after bolus injection of contrast medium, and 25 images were acquired. Our theoretical model of contrast enhancement was applied to analyse time-density curves, and the following parameters were obtained: Ki (inward flux constant), Kb (backward flux constant), Vp (vascular plasma volume), and lambda (extracellular fluid space volume). Furthermore, functional maps were generated from parameters for each pixel. Changes in intra-arterial iodine concentration, required in our model, were measured from CT numbers in the superior sagittal sinus. We have investigated several aspects of our method. Histological findings in surgical specimens of intracranial tumours agreed well with the parameters obtained by our method. Vp was verified quantitatively by single photon emission computed tomography. Our method was shown to be reproducible. These results show that the parameters are useful for assessing tumours and in planning chemotherapy. Our method, which employs no special equipment, is readily available at any institution.

Adult↗

PubMed1992

Local blood flow changes in malignant brain tumours under induced hypertension.

Changes in tumour blood flow under an induced hypertensive state were examined in malignant brain tumours to know if the precondition for the effectiveness of induced hypertensive chemotherapy--relative increase in tumour blood flow--are fulfilled. Tumour blood flow was measured under both a resting and an induced hypertensive state in 12 patients with various malignant brain tumours (6 gliomas, 6 metastatic brain tumours) using xenon-enhanced computed tomography. The blood pressure was elevated 40% above the systemic blood pressure of the resting state by the infusion of angiotensin II. Tumour blood flow increased 30% on average above the normal brain tissue blood flow after the induction of an induced hypertensive state (p < 0.05). The tumour blood flow increased in 11 cases of malignant tumours, but decreased in one case with massive brain oedema after induced hypertension. The increase in blood flow was higher in hypervascular tumours and less in hypovascular tumours. Therefore, induced hypertensive chemotherapy probably will be more effective in hypervascular malignant brain tumours with small mass effects.

Adult↗

PubMed1992

Autotransplantation of peripheral cholinergic neurons into the brains of Alzheimer model rats.

Current hypotheses regarding Alzheimer's disease implicate cholinergic function. In this study, peripheral cholinergic neurons in the vagal nodosal ganglion were transplanted into the brains of Alzheimer model rats. Eighteen Sprague-Dawley strain rats were divided into three groups: 1) unoperated control rats, 2) rats that had undergone bilateral destruction of the nucleus basalis of Meynert (NBM) (Alzheimer model), and 3) the transplantation group in which the vagal nodosal ganglion was transplanted into the cerebral neocortex one week after the bilateral destruction of the Meynert nucleus. Seven weeks after the transplantation rat behaviour was assessed using psychological tests (spontaneous activity, passive avoidance response and the Hebb-Williams maze test). The Alzheimer model rats had a statistically significant increase in spontaneous activity in comparison with controls (P less than 0.01). The transplant rats showed some amelioration of this abnormal increase in spontaneous activity observed in the Alzheimer model rats. All of the control rats showed conditioned passive avoidance responses, while only one Alzheimer model rat retained is shocked-conditions behaviour before 24 hours (P less than 0.01). Three of the six transplanted rats showed complete improvement in the passive avoidance response test. In the Hebb-Williams maze test, the rats with NMB lesions made more errors than the control rats. The transplanted rats had a lower number of errors than NBM-lesioned rats but still more than the controls. Histological examination revealed many cholinergic cells in the transplanted tissue, especially in the area adjacent to the cerebral cortical surface. The present results indicate that autotransplantation of peripheral cholinergic cells ameliorates abnormal behaviour in Alzheimer model rats.

Alzheimer Disease↗

PubMed1992

A study of right unilateral spatial neglect in left hemispheric lesions: the difference between right-handed and non-right-handed post-stroke patients.

We report 20 cases of right unilateral spatial neglect caused by lesions in the left cerebral hemisphere. Differences in neuropsychological symptoms and lesions sites are discussed in connection with handedness. Of the right-handed patients, 6 had severe aphasia, 4 had Gerstmann's syndrome, and 1 had pure agraphia, but unilateral spatial neglect in these cases disappeared after a number of months. Six of the non-right-handed patients had moderate-to-severe aphasia, while the other 3 cases had no aphasia at all. Eight of the 9 cases in this group continued to have right unilateral spatial neglect for more than 6 months. Lesion site as determined by CT differed as to hemisphere, but all fell into the common area previously mentioned in connection with such disorders: i.e., the temporal, parietal and occipital lobes.

Adult↗

PubMed1992

A possible involvement of central atrial natriuretic peptide in cerebral cortical microcirculation.

The possible involvement of atrial natriuretic peptide (ANP) in cerebral cortical microcirculation was investigated in rats by means of laser-Doppler flowmetry and immunohistochemistry. In the laser-Doppler study, local cerebral blood flow (LCBF) changes after the administration of 10(-6) to 10(-8) mol/LANP solution or vehicle (saline solution) as an intracortical injection for 5 minutes were continuously monitored throughout the 30 minutes of the study and were expressed as percentages of preinjection values represented as 0%. The administration of 10(-6) to 10(-8) mol/LANP caused a significant decrease in LCBF; the onset of LCBF responses occurred within a few minutes after the start of the injection and the decrease in LCBF reached the maximum level within 7 to 10 minutes after the completion of the administration, after which LCBF gradually recovered. In the immunohistochemical study, no specific ANP immunoreactivity was found associated with the intraparenchymal blood vessels; however, ANP-immunoreactive neurons were observed primarily in the hypothalamus and septum, in which high concentrations of ANP-containing neurons have been identified. The data from the laser-Doppler study suggest that central ANP may produce a vasoconstriction of the intraparenchymal blood vessels, regardless of whether through direct action on these vessels or through the mediation by some system in the central nervous system. Because there is no evidence for ANP-containing nerves around these vessels, the role of central ANP in the cerebral circulation must await identification of the source of perivascular ANP.

Animals↗

PubMed1992

Postauricular response in motor paresis with intracranial lesions.

The clinical usefulness of the postauricular response (PAR) in the evaluation of motor paresis was studied in 105 patients with intracranial lesions and 25 normal volunteers. Click stimuli at 90 dB hearing level were delivered in each ear, and PARs recorded from bilateral posterior auricular muscles with reference to the vertex (Cz). No volunteer demonstrated PAR in the relaxed posture, but in tensed postures increasing muscle tone PARs were elicited with a latency of 11.5 +/- 0.7 msec and an amplitude of 6.2 +/- 2.8 muV. Sixty-two patients (59%) had high-amplitude PARs in the relaxed posture. PARs were enhanced more frequently in paretic patients than in non-paretic patients (p less than 0.01). In subcortical lesions, the PAR latency had a significant correlation with the degree of motor paresis (p less than 0.005). In patients, the enhanced PAR amplitude suggested the presence of motor paresis associated with deep-seated mass lesions. The enhanced response is thought to be associated with dysfunction of the pyramidal and extrapyramidal tracts.

Brain Diseases↗

PubMed1992

Meningeal melanocytoma: magnetic resonance imaging characteristics and pathological features. Case report.

A case of meningeal melanocytoma at the foramen magnum is reported in a 62-year-old man. Magnetic resonance (MR) imaging revealed characteristic signal patterns: homogeneous high intensity on the T1-weighted image and low intensity on the T2-weighted image. Light microscopy showed a histological appearance similar to that of melanotic meningioma. The ultrastructural features of the neoplastic cells were compatible with those of melanocytes, but they contained no features of arachnoidal cells. Immunohistochemical bromodeoxyuridine study revealed low proliferative activity among the neoplastic cells. The MR appearance and pathological features in this rare case of meningeal melanocytoma are demonstrated and discussed.

Humans↗

PubMed1992

Bilateral morning glory syndrome associated with sphenoid encephalocele. Case report.

Morning glory syndrome is a congenital anomaly of the optic disc in which the disc is enlarged and excavated, with white glial tissue in the center. A case is presented of morning glory syndrome associated with sphenoid encephalocele, median cleft lip, and agenesis of the corpus callosum. A 22-day-old boy was referred to the Wakayama Medical College Hospital for management of dyspnea due to a soft-tissue mass in the oral cavity. Magnetic resonance imaging revealed a mass extending through a bone defect in the sphenoid region and into the oral cavity. Surgical repair was attempted through a bifrontal craniotomy. A bone defect was identified in the sphenoid plate, through which the arachnoid membrane was connected to the oral cavity. Both optic nerves were elongated and adhered to the encephalocele. The wall of the meningocele was compressed digitally through the oral cavity and sutured to the dura mater of the bone defect. The operative findings suggest that a basal encephalocele protruding from a bone defect in the sphenoid plate may disturb the normal development of the optic nerve.

Abnormalities, Multiple↗

PubMed1992

[Pitfalls of endovascular treatment for cerebral aneurysms].

Seventeen cases of unclippable aneurysms were treated by the endovascular balloon technique. Nine of them involved the anterior circulation, and eight involved the posterior circulation. Eleven of them were treated by parent artery occlusion with detachable balloons. Three were treated by endosaccular balloon embolization, and three cases combined with AVMs were occluded using ethylene vinyl alcohol copolymer (EVAL) including feeding arteries of the AVMs. Embolic complications occurred in one case of an IC bifurcation giant aneurysm treated by parent artery occlusion. Ischemic complications also appeared in two cases of aneurysms treated by endosaccular balloon embolization. In one case, the thrombus in the aneurysm propagated into the parent artery and occluded it later. In another case, the displaced balloon had obliterated the parent artery 6 hours after the embolization. Parent artery occlusion is a safe way to treat internal carotid giant aneurysms. However, endosaccular treatment still has some problems, i.e., 1) maintaining the balloon's position to preserve the parent artery, 2) balloon migration into the clot, 3) rupture of the aneurysm during or after treatment. Our studies indicate that endosaccular balloon embolization is still a high risk procedure and should be used only in selected cases, until new embolic agents, such as detachable coils, become available.

Adult↗

PubMed1992

[Pitfalls in cortical localization by intraoperative recording of cortical somatosensory evoked potentials].

Cortical somatosensory evoked potential (SEP) recordings were made in 11 patients who had lesions located in or near the somatosensory or motor gyri to localize the central sulcus and sensorimotor cortex during neurosurgical operations. Cortical localization was successful in 7 of the 11 patients by recording phase reversal waveforms of N20 and P20 at electrode sites in the hand area on opposite sides of the central sulcus. There were 4 cases in which the cortical localization failed. Locations of craniotomy were far distant from the central sulcus retrospectively in 2 of the 4 patients. Cortical SEPs couldn't be recorded despite probable exposure of the hand area and apparently adequate stimulation and recording conditions in 2 patients who had showed no or low amplitude scalp SEP preoperatively. In one of these 2 patients only low amplitude negative waves were recorded at the cortex which was thought far field potentials originated from subcortical structures. In 2 patients cortical SEP was monitored during the removal of the tumors and was useful to estimate the effects of the operative procedures on the sensorimotor cortex. It is concluded that the localization of cortical functions using cortical SEP is useful for reducing risk associated with intracranial surgery. However, we must be aware that there are some pitfalls in this method.

Adolescent↗

PubMed1992

[A case of parkinsonism induced by an oral contraceptive].

We report a case of parkinsonism induced by long term administration of an oral contraceptive. A 38-year-old woman complained of easily stumbling, démarche à petit pas and fatiguability in her lower extremities since January, 1991. When examined on April 5, 1991, she explained taking an oral contraceptive for 7 years on her doctor's recommendation after two times artificial abortions. Her facial expression was mask-like and body was bent forward with knee joints flexed and arms flexed at elbow joints. She had frozen gait with inactive pendulousness of the arms. We could find her muscle rigidity in both upper and lower extremities, especially in her right side extremities. A brain MRI finding was lacunar infarction which proton density weighted and T2-weighted MR images showed small patches of high-signal intensities in white matter of the bilateral frontal lobes and in left periventricular white matter. Her symptoms improved after stopping administration of the oral contraceptive and starting combination therapy with nicergoline and bromocriptine. She had some leg fatiguability at the onset of her next menstruation in May, but it was much less than her previous condition. When her menstruation terminated, those symptoms disappeared and it was possible to stop the administration of bromocriptine and nicergoline, and her symptoms have improved.

Adult↗

PubMed1992

[Three dimensional display of cerebral vessels using a personal computer].

A new method for a 3-D reconstruction of angiographic cerebral vessels was developed. This system was constructed from inexpensive equipment such as a personal computer, a video camera, a video display, and a digitizer. The input of the vessel images on anteroposterior and lateral angiograms was performed using a video camera with a personal computer and an image processing program (FDM 98-4; Fotoron Co.). These processed images were modified with our original editorial method. This can contribute a lot to the erasing of "non-vessel" images such as skull bone and other noise. It also adds concerning vessels which cannot be clearly taken from angiograms with the video camera. The most beneficial point of the editorial method was to reduce the time consumed in the reconstruction. The spatial points of X-ray discharging boxes against the AP and lateral films were calculated from the length and width of the radiated images of metal bars. These bars were attached to the 3 planes of the lucent box in which the patient's head was inserted to take the angiograms. The 3-D points of the vessels were calculated as follows; one point of a vessel on the lateral image and the spatial point of the X-ray discharging box against the image were linked by a line on which a point moved within a Z range. When the extended line which linked the point and the position of the X-ray discharging box against the AP view crossed the AP image, the Z value of the point was adopted and X and Y values were gained.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Angiography↗

PubMed1991

Dynamic computed tomography for the evaluation of cerebrovascular disease.

Dynamic computed tomography (DCT) was evaluated as a diagnostic indicator for chronic supratentorial ischemia in 50 cases with or without minor neurological deficits. Peak height (PH, the maximum value of the gamma fitted curve), peak time (PT, the time to PH from the start of DCT), transit time (TT, the time between the first and second inflection points of the gamma fitted curve), and their functional maps were analyzed. Cerebral angiography was then performed in all cases to identify stenotic or occlusive vascular lesions in major cerebral arteries. DCT clearly detected 12 of 13 occlusions of the internal carotid artery (ICA) or middle cerebral artery (MCA), although one ICA occlusion was masked by the contralateral MCA occlusion. However, DCT detected only severe ICA or MCA stenosis (more than 90%). Probably, stenotic lesions of less than 90% did not cause detectable hemodynamic compromise. DCT using PH, PT, and TT functional maps is a useful diagnostic method for hemodynamic changes in ischemic cerebrovascular disease, although bilateral lesions and less stenotic lesions (less than 90%) are difficult to detect.

Adult↗

PubMed1991

Ruptured cerebral aneurysm successfully clipped in idiopathic thrombocytopenic purpura after high-dose gamma-globulin therapy--case report.

A ruptured cerebral aneurysm in a 50-year-old female with idiopathic thrombocytopenic purpura was successfully clipped after preoperative high-dose gamma-globulin therapy to control the hemorrhagic diathesis. High-dose gamma-globulin therapy with or without steroid and/or platelet transfusion is recommended for such cases if the blood pressure can be controlled and the neurological condition permits delayed surgery.

Blood Loss, Surgical↗

PubMed1991

Embolization of arteriovenous malformations with peripheral aneurysms using ethylene vinyl alcohol copolymer. Report of three cases.

The authors report three cases of arteriovenous malformations (AVM's) with aneurysms arising from the feeding artery; all were successfully treated with a new nonadhesive liquid embolic material, ethylene vinyl alcohol copolymer (EVAL). In two patients the AVM's were totally removed without difficulty, and in one the AVM was managed conservatively after embolization. No new neurological deficits appeared during or after embolization. After road-mapping techniques, EVAL was injected slowly until the feeding artery and aneurysm were completely obliterated. This embolic agent is easy to handle and is considered safe compared with other adhesive liquid embolic agents, such as isobutyl-2-cyanoacrylate or n-butyl cyanoacrylate. It is concluded that EVAL is an excellent agent for embolizing an AVM with a peripheral aneurysm on the feeding artery.

Adult↗