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Biomedical subjects

O Hirai

Publications and source records attributed to O Hirai.

At least 19 recordsLinked to original sources
PubMed1998

[Ruptured aneurysm of the marginal branch of the superior cerebellar artery: case report].

The authors report a rare case of a ruptured aneurysm arising from the marginal branch of the left superior cerebellar artery. At the first retrosigmoid craniectomy carried out on the day of hospitalization, the clip was wrongly placed on the anterior inferior cerebellar artery (AICA). The unanticipated accident was due to incomplete dissection of a thick and severely adhered subarachnoid clot and the mistake was made because the course of the marginal artery was similar to that of the AICA. At the second operation undergone 1 week later, the aneurysm was easily and successfully clipped. After ventriculoperitoneal shunting, the patient returned to normal except for left hearing loss. The authors suppose that delayed surgery would be beneficial as a rule for ruptured aneurysms of the peripheral branch of the cerebellar arteries not only because dissection is easier but also because the risk of rebleeding and vasospasm are reported to be low in such aneurysms.

Aged↗
PubMed1997

Fully-automated roller bottle handling system for large scale culture of mammalian cells.

A fully automatic and continuous cell culture system based on roller bottles is described in this paper. The system includes a culture rack storage station for storing a large number of roller bottles filled with culture medium and inoculated with mammalian cells, mass-handling facility for extracting completed cultures from the roller bottles, and replacing the culture medium. The various component units of the system were controlled either by a general-purpose programmable logic controller or a dedicated controller. The system provided four subsequent operation modes: cell inoculation, medium change, harvesting, and medium change. The operator could easily select and change the appropriate mode from outside of the aseptic area. The development of the system made large-scale production of mammalian cells, and manufacturing and stabilization of high quality products such as erythropoietin possible under total aseptic control, and opened up the door for industrial production of physiologically active substances as pharmaceutical drugs by mammalian cell culture.

Animals↗
PubMed1994

Microbial mutagenicity and in vitro chromosome aberration induction by FK973, a new antitumor agent.

The genotoxic activity of a new antitumor agent, FK973, was compared with that of mitomycin C (MMC) in eukaryotic and prokaryotic cells. In chromosome aberration tests using Chinese hamster fibroblast Don cells, FK973 induced a dose-related increase of aberrant cells after 6 h-pulse treatments, and the minimum effective concentrations with and without S9 were 0.625 and 0.0625 micrograms/ml, respectively. The compound increased revertant colonies in Salmonella typhimurium TA102 at the dose range of 10-5000 micrograms/plate with S9. Without S9, FK973 induced a small increase at the dose range of 500-5000 micrograms/plate in two of three independent experiments, but the number of revertant colonies was less than double that of the vehicle control. The compound did not induce any revertant colonies in colonies in S. typhimurium TA100, TA98, TA1535 or TA1537 with or without S9. MMC was confirmed to increase both chromosome aberrations in Don cells and revertant colonies in TA102. The minimum clastogenic and mutagenic concentrations without S9 were 0.0156 microgram/ml and 0.005 microgram/plate, respectively. The results indicate that FK973 needs metabolic activation to induce reverse mutation in prokaryotic cells, but caused chromosome aberrations in mammalian cells without added S9.

Animals↗
PubMed1994

Mutagenicity tests of polyoxyethylene hydrogenated castor oil 60 (HCO-60).

The genotoxicity of polyoxyethylene hydrogenated castor oil 60 (HCO-60) was examined in reverse mutation test in bacteria, chromosome aberration test in vitro and micronucleus test in mice. The in vitro tests were done with and without metabolic activation using rat liver microsomal fraction. HCO-60 did induce neither reverse mutation in Salmonella typhimurium TA100, TA98, TA1535, and TA1537 and in Escherichia coli WP2uvrA, nor chromosome aberrations in Chinese hamster V79 cells. In addition, no increase in micronucleated polychromatic erythrocytes was elicited in the bone marrow of BDF1 male and female mice. It is concluded that HCO-60 was not genotoxic in these in vitro and in vivo assays.

Animals↗
PubMed1994

[Idiopathic normal pressure hydrocephalus in the aged].

Continuous lumbar cerebrospinal fluid pressure measurement was made in 19 cases of aged patients suspected of idiopathic normal pressure hydrocephalus. Based on the pressure study, they were divided into high pressure group (H group) and normal pressure group (N group). H group was composed of 11 cases and N group of 8 cases. Baseline pressures in H group and N group were 16.3 +/- 3.0 mmHg, 9.6 +/- 1.7 mmHg, respectively and the difference was statistically significant. Pulse pressure was high in H group and frequency of pressure waves was also significantly high in H group. There were no significant differences in clinical symptoms and CT findings between the two groups, except for clinical improvement after cerebrospinal fluid removal, which was noted in all of 6 cases examined in H group. No difference between them was noted on CT cisternography and cerebral blood flow measurement. Shunt surgery was carried out in the cases of H group and it was effective in 8 of 11 cases (72.7%). Thus, continuous lumbar cerebrospinal fluid measurement was useful for selection of idiopathic normal pressure hydrocephalus in the aged.

Aged↗
PubMed1993

C-type natriuretic peptide (CNP) is the major natriuretic peptide in human cerebrospinal fluid.

In order to investigate whether C-type natriuretic peptide (CNP) is present in human cerebrospinal fluid (CSF), we measured CNP-like immunoreactivity (-LI) in human CSF by specific radioimmunoassay (RIA) for CNP. We also measured atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) concentrations in human CSF. ANP-LI, BNP-LI, and CNP-LI concentrations of CSF collected from fifteen patients without neurological disorders were 0.20 +/- 0.13, 0.27 +/- 0.10, and 2.13 +/- 0.27 fmol/ml (mean +/- S.D.), respectively. In fifteen patients with neurological disorders, ANP-LI, BNP-LI, and CNP-LI concentrations in CSF were 0.21 +/- 0.18, 0.33 +/- 0.19, and 2.09 +/- 0.82 fmol/ml, respectively. Although ANP-LI and BNP-LI concentrations in plasma were much higher than those in CSF, CNP-LI was undetectable in plasma (less than 0.2 fmol/ml). These results demonstrate that three natriuretic peptides are present in CSF and that CNP is the major natriuretic peptide in human CSF. These results suggest that CNP in CSF is originated from and play important roles in the central nervous system.

Adult↗
PubMed1992

Skull base metastasis from gastric cancer--case report.

A 48-year-old male presented with a metastatic skull base tumor located on the right of the clivus and the sphenoid sinus, which originated from adenocarcinoma of the stomach. The initial symptom was abducens nerve paralysis and there were no symptoms of upper gastrointestinal tract throughout the course. This gastric cancer, which rarely metastasizes to the central nervous system or osseous system, caused multiple bone metastases which produced the neurological symptoms.

Carcinoma↗
PubMed1991

Prior bleeding enhances the sensitivity of the in vivo micronucleus test.

It has been reported that the sensitivity of the in vivo mouse bone marrow micronucleus test can be increased by inducing erythropoiesis with exogenous erythropoietin prior to treatment (Suzuki et al., 1989). In these studies we demonstrate that removing approximately 0.5 ml of blood from an adult male BDF1 mouse, another method for increasing the rate of erythropoiesis, synergistically increased the frequency of bone marrow micronucleated polychromatic erythrocytes induced by mitomycin C, with maximal enhancement occurring when the mutagen was given 24 h after bleeding. This enhancement response was also demonstrated for benzo[a]pyrene and dimethylnitrosamine but not for 2-acetylaminofluorene. These results indicate that bleeding mice prior to chemical treatment is a simple method for increasing the sensitivity of the micronucleus assay.

Animals↗
PubMed1991

Endodermal epithelial cyst in the prepontine cistern extending into the fourth ventricle--case report.

The authors report a case of epithelial cyst, which recurred 32 years after the initial surgical treatment. Computed tomography showed no abnormality, but magnetic resonance (MR) imaging clearly demonstrated a well-demarcated mass in the prepontine cistern, extending into the fourth ventricle. The lesion showed extreme hyperintensity compared with the surrounding brain on both the T1- and T2-weighted images. The ultrastructural features of the cyst suggested an endodermal origin. MR imaging and electron microscopy are essential for correct diagnosis and exact pathogenetic identification of intracranial cystic lesions.

Brain Diseases↗
PubMed1991

[Ventricular dilation during the treatment of subdural hygromas].

Fifty-one cases with subdural hygroma experienced in the past 20 years were retrospectively reviewed. Eight patients showed definite ventricular dilation differing from simple restoration of the ventricles following disappearance of the cavity. The mean age was 72.4 years. Six patients presented with mental change as the initial symptom. On the initial computed tomography (CT), 75% of the cases had bilateral lesions, all were low density, and 88% were crescent shaped. Trepanation performed on six patients yielded watery clear or xanthochromic fluid. Nine to 61 days (mean 4 weeks) after admission, definite ventricular dilation was observed. Cisternography performed in four patients was all abnormal, although cerebrospinal fluid (CSF) pressure was within normal range. Cerebral blood flow images using 123I-iodoamphetamine and single photon emission CT in four patients revealed periventricular low uptake which was disproportionately large compared with the ventricular span on CT. A ventriculoperitoneal shunt was placed in four patients. The final outcome, however, was poor irrespective of treatment. These findings indicate that an impairment of the CSF circulation was not the sole cause of the ventricular dilation. Low CSF pressure and the disproportionately large periventricular low perfusion, compared with the ventricular span on CT scan, suggest a pre-existing periventricular parenchymal damage, which had been subsequently compromised by the presence of subdural mass lesion. Therefore, attention should be paid in aged patients with bilateral low dense, crescent-shaped subdural hygroma, presenting with mental change, for the risk of subsequent ventricular dilation which may affect the functional outcome.

Aged↗
PubMed1991

[Anterior decompression surgery of aged patients with cervical myelopathy].

One hundred and thirty-nine patients with cervical myelopathy who underwent anterior decompression surgery were reviewed to determine the characteristics and surgical outcome in 26 elderly patients over the age of 65. The mean age of the aged group was 69.7 and that of the remaining 113 patients was 50.0. Extensive spur removal and interbody fusion with iliac bone graft were performed in all patients. Evaluation of clinical grades was based on the Japan Orthopedic Association Score (JOA score) on admission, at discharge and at the time of follow-up (mean 26.8 months). The improvement rate was calculated from Hirabayashi's formula at each point. Preoperatively, the mean duration of illness was longer and the mean JOA score was significantly lower in the aged group. Furthermore, low incidence of soft disc and multi-level lesions were characteristic for the aged. Final JOA score increased from 8.2 to 13.0 in the aged group, while that in the non-aged group increased from 10.5 to 14.8. These differences were statistically significant at each point. Excellent and good results which were designated as an improvement rate of 50% or more were obtained in 73.1% of the aged group, and in 79.6% of the non-aged group. Postoperative complications were slightly more frequent in the aged group, all of which, however, were dislocation of bone graft seen in 3 patients. As compared with the non-aged group, poorer surgical outcome in the aged group was attributed to preoperative poor clinical condition, long duration of preoperative symptoms, low incidence of soft disc herniation and multi-level lesions which were characteristic features for the aged patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1989

Intolerable pulse-synchronous tinnitus caused by occlusion of the contralateral common carotid artery. A successful treatment by aorto-carotid bypass surgery.

A case with severe pulsatile tinnitus of the left side caused by occlusion of the right common carotid artery was reported. Tinnitus in this case was supposed to be due to the rich blood flow of the external carotid systems developed as collateral routes resulting from the occlusion of the right common carotid artery. It subsided with the establishment of a bypass using a vein graft between the ascending aorta and the residual patent portion of the right common carotid artery.

Aorta↗
PubMed1989

[Cerebral hemodynamics and functional prognosis in hydrocephalus].

The functional outcome of cerebral hemodynamics in the chronic stage of juvenile hydrocephalus was determined using single photon emission computed tomography (SPECT). Five patients including three with aqueductal stenosis, one with post-meningitic hydrocephalus, and one case with hydrocephalus having developed after repair of a huge occipital encephalocele. Early images of cerebral blood flow (CBF) were obtained 25 minutes after intravenous injection of 123-I-Iodoamphetamine (IMP), and late images were scanned 3 hours later. Cerebral blood volume (CBV) was also measured using 99mTc in three patients. Twenty cases with adult communicating hydrocephalus were also investigated from the point of view of shunt effectiveness. Although there was no remarkable change in the cerebrovascular bed in the juvenile cases, CBF of the remnant brain parenchyma was good irrespective of the degree of ventricular dilatation. There was a periventricular-reduced IMP uptake in each case, however it somehow matched the ventricular span. Functional outcome one to 23 years after the initial shunt operation was good in every case, despite multiple shunt revisions. Redistribution on late images had no bearing on clinical states. In adult cases, 8 patients with effective shunting demonstrated a relatively localized periventricular low perfusion, with preoperative increased cerebrospinal fluid (CSF) pressure. On the contrary, 12 patients with no improvement with or without shunting showed disproportionately widespread periventricular-reduced IMP uptake, despite low CSF pressure. The present study indicates that periventricular hemodynamics may play an important role in cerebral function compromised by hydrocephalus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Factors responsible for prognosis of chronic subdural hematomas].

239 adult patients with chronic subdural hematoma were reviewed in order to analyse recent characteristics, and the responsible factors affecting functional prognosis. Patients with hygroma, diagnosed by the nature of the subdural fluid, were included since the mode of treatment is regarded as the same. 226 cases were surgically treated with standardized two burr-holes and irrigation, within which 24 cases required reoperation and 13 cases were medically treated since the hematoma was small and there was no mass effect. Functional outcome was evaluated by the Glasgow Outcome Scale. The number of cases have gradually increased, especially among elderly patients and in female ones. 179 patients were categorised as having good recovery, 25 as moderately disabled, 27 as severely disabled, 3 as persistently vegetative, and 5 patients died. Aged patients with preoperative mental change and a disturbance of consciousness, with low dense or mixed dense hematoma without sizable mass effect, with watery-clear or xanthochromic fluid cavity tended to have poorer outcome. Also the prognosis of patients not operated on was poor despite the spontaneous disappearance of the cavity. The delay in re-expansion of the brain had less bearing on the functional prognosis than might be expected. The factors which impeded good recovery were primary brain damage due to preceding diseases such as cerebral infarct or hemorrhage, initial head injury, parkinsonism, and postoperative psychiatric disturbances. The mean age of these patients was significantly higher than those with good recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Continuous lumbar subarachnoid pressure monitoring as an indicator of shunt operation for so-called normal pressure hydrocephalus].

Lumbar subarachnoid pressure (LSP) was continuously monitored via intrathecally introduced polyethylene catheter to select the patients for shunt operation. A total of seventy cases included so-called normal pressure hydrocephalus (NPH) secondary to subarachnoid hemorrhage (SAH; 34 cases), idiopathic NPH (17 cases), secondary NPH whose symptoms developed after operations for brain tumors, head injuries or meningitis (12 cases) and other intracranial diseases including pseudotumor cerebri or meningeal carcinomatosis, etc. (7 cases). Shunt operation was effective in 36 cases and not effective in 9 cases, while 25 cases were not shunted since LSP was not elevated or clinical manifestations were slight. Mean values of baseline pressure and maximum pressure in shunt effective group, shunt non-effective group and non-shunted group were 14.5, 12.7, 9.0 and 29.9, 25.0, 17.9 mmHg, respectively. Statistical difference was observed between shunt effective group and non-shunted group. Frequency of pressure waves was also significantly higher in shunt effective group than in non-shunted group. Above all, measurement of LSP was regarded as useful in idiopathic NPH. However, preoperative clinical symptoms had a closer relationship to shunt response than results of LSP in post SAH patients. Complication related to this monitoring was negligible except in one case of meningitis which was easily treated by administration of antibiotics. Follow-up study also justified our selection since no further deterioration was noted in non-shunted group. The present study indicates that measurement of LSP would be useful in selecting the patients who will benefit from shunting and in eliminating unnecessary shunt operations because this simple method is easily performed at bed side without perforating the skull.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Spontaneous hematomyelia properly diagnosed with magnetic resonance imaging].

A case of spontaneous hematomyelia with symptoms localized to the C 5-6 level is presented. Myelography and metrizamide CT scan failed to demonstrate the lesion, while magnetic resonance imaging clearly revealed a small intramedullary mass in the ventral portion of C 3-4. Subsequent intensity changes over four weeks indicated the lesion to be hematoma. The patient was successfully treated through an anterior approach.

Adult↗