Shoji Asari

Natural history and risk factors of unruptured cerebral aneurysms

We report the results of a statistical analysis of the long-term outcome of 54 patients with 72 unruptured cerebral aneurysms, and identify the factors for predicting subsequent ruptures. Twenty-two patients died during the observation period, which averaged 43.7 months. The 5-year survival rate was 56%. Aneurysms ruptured in 11 patients (20.4%), 10 of whom died without undergoing surgery. The annual bleeding rate was 1.92%. The average size of the 11 ruptured aneurysms was 13.1 mm. In 4 patients, however, bleeding occurred in unruptured cerebral aneurysms of 4 and 5 mm, which suggests that leaving unruptured cerebral aneurysms of less than 10 mm in size untreated is hazardous. According to the Cox proportional hazards model, the shape and location of the aneurysm and the presence of hypertension were the most important factors for predicting a subsequent rupture. Our data suggest that unruptured cerebral aneurysms arising from the vertebrobasilar and middle cerebral arteries of 10-19 mm size and of multilobes had a statistically high probability of subsequent bleeding. Although 20 patients with 28 unruptured cerebral aneurysms were followed through repeated examinations, we could not correlate the risk of subsequent bleeding with changes in the size of the aneurysm.

Enhanced recovery of the nigrostriatal dopaminergic system in MPTP-treated mice following intrastriatal injection of basic fibroblast growth factor in relation to aging.

Studies have suggested that the restorative effects of adrenal medullary chromaffin cell grafts in animal models of Parkinsons disease may be related to trophic factors contained within the chromaffin cells. Basic fibroblast growth factor (bFGF) is present in chromaffin cells and has been shown to exert trophic effects on dopaminergic neurons in vitro. Basic FGF was stereotaxically injected into the striatum of young (2-month-old) and aging (12-month-old) C57BL/6 mice which had been treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) 1 week earlier. MPTP treatment reduced tyrosine hydroxylase (TH)-immunoreactive (IR) fibers in the striatum and striatal dopamine (DA) concentration in both the young and older mice 5 weeks later. Computerized image analysis of striatal DA fibers in young mice treated with bFGF showed significant recovery of DA fibers up to 600 microns from the injection site 5 weeks after MPTP administration. Striatal DA fibers in older mice treated with bFGF showed significant recovery only up to 300 microns from the injection site, and the degree of recovery was very limited compared with young mice. HPLC analysis of DA concentration revealed that striatal DA in young mice recovered significantly when treated with bFGF, but no significant recovery was observed in older mice. It is concluded that bFGF enhances the recovery of striatal DA systems from MPTP toxicity both in young and in older mice, but that such benefits are very limited in older mice.

The relationship between brain surface elastance and brain re-expansion after evacuation of chronic subdural hematoma

BACKGROUND Brain stiffness has been thought to be a factor affecting brain re-expansion after the evacuation of chronic subdural hematoma. METHODS As an index of brain stiffness, the pressure for compressing the brain using an ophthalmodynamometer was defined as brain-surface elastance. This elastance in 14 patients was measured and analyzed in relation to brain re-expansion. RESULTS Patients with an enlarged subdural space on computed tomography 1 month after the operation had higher elastance. There was a correlation between high elastance and high age. CONCLUSIONS Measuring the elastance after evacuation of the hematoma may help predict the persistence of a subdural space.

MR appearance and cyst content of Rathke cleft cysts.

The magnetic resonance signal intensity and cyst content were analyzed in 2 new and 17 previously reported cases of Rathke cleft cyst. Lesions displaying hypointensity on T1-weighted images (T1WI) and hyperintensity on T2-weighted images (T2WI) contained CSF-like fluid. Cases showing hyperintensity on T1WI and isointensity on T2WI frequently contained mucoid material. Hyperintensity on both T1WI and T2WI suggests the presence of blood. A small area of hypo- or isointensity indicates thickening of the cyst wall or collection of cellular debris.

Assessment of the pathological grade of astrocytic gliomas using an MRI score

To evaluate the usefulness of an MRI score for identifying tumour tissue characteristics, 41 histologically verified supratentorial astrocytic gliomas, including 13 low-grade astrocytomas (LGA) 14 anaplastic astrocytomas (AA) and 14 glioblastoma multiformes (GBM), were examined with a 0.5T superconductive MR imager. Nine MRI criteria were used: heterogeneity (HET), cyst formation or necrosis (CN), haemorrhage (HEM), crossing the midline (CM), oedema or mass effect (EM), border definition (BD), flow void (FV), degree (CE-D) and heterogeneity (CE-HET) of contrast enhancement; Gd-enhanced T1-weighted images were obtained in 32 cases (10 LGA, 10 AA, and 12 GBM). Each of the criteria was scored and analysed statistically. The mean values of LGA, AA and GBM were 0.45±0.31, 1.18±0.20, and 1.47±0.22, respectively. The MRI score increased with the pathological grades (P<0.01–0.001). LGA had significantly lower values than AA in five (HET, CN, EM, BD, CE-D) of the nine criteria (55.6%) and lower values than GBM in all except HEM (88.9%). Three criteria (33.3%): HET, CN, and FV were significantly higher in GBM than AA. CE-D, HET, EM, CN, and CE-HET proved to be related to the pathological grade by a multiple regression analysis (P<0.001).

Neurinomas Presenting as Spontaneous Intratumoral Hemorrhage

Massive intratumoral or subarachnoid hemorrhage from neurinomas is very rare. The authors report on six patients, four men and two women, with neurinomas that presented as spontaneous intratumoral hemorrhage. The average age of the patients was 56.8 years (range, 31-74 years). Neurinomas originated from the acoustic nerve in four patients and from the trigeminal nerve in two. Four cases were accompanied by the sudden occurrence of clinical symptoms such as headache, double vision, and hemisensory or motor disturbance. The maximum diameter of the tumors ranged from 2.8 to 3.8 cm (average, 3.1 cm). Histological examinations showed massive hemorrhage and increased vascularity, with dilated, thin-walled vessels, in all cases. The size of the tumor and the increase in vascularity with dilated, thin-walled vessels within neurinomas are important pathogenetic factors of hemorrhage. When sudden onset of symptoms or rapid worsening of chronic symptoms occurs in neurinomas, intratumoral or subarachnoid hemorrhage should be considered as a possible cause, and magnetic resonance imaging can be an important tool in obtaining correct diagnosis.

Inhibition of Poly(ADP-Ribose) Polymerase Attenuates Cerebral Vasospasm After Subarachnoid Hemorrhage in Rabbits

Background and Purpose— Poly(ADP-ribose) polymerase (PARP) is important in modulating inflammation, which has been implicated in cerebral vasospasm after subarachnoid hemorrhage (SAH). We investigated the role of PARP in vasospasm using 3-aminobenzamide (3-AB), a PARP inhibitor, in a rabbit model. Methods— Twenty-four New Zealand White rabbits were divided into 4 groups: (1) no treatment (control group, n=6); (2) blood injection without pretreatment (SAH-only group, n=6); (3) blood injection with pretreatment by vehicle (SAH+vehicle group, n=6); and (4) blood injection with pretreatment by 3-AB (SAH+3-AB group, n=6). We used the single-hemorrhage model of SAH, injecting autologous arterial blood into the cisterna magna. Angiography was performed before (baseline) and after (day 2) SAH, and the diameter of the basilar artery (BA) was measured. Animals were euthanatized after the second angiogram. After perfusion and fixation, the brains were cut into sections for hematoxylin and eosin and immunohistochemical staining for poly(ADP-ribosyl)ation. Results— In the control group, there were no differences in the BA lumen caliber between baseline and day 2 (96.8±10.4%). Cerebral vasospasm in the SAH+3-AB group (88.2±6.2%) was remarkably attenuated in comparison with that in the SAH-only group (64.9±8.0%) and the SAH+vehicle group (65.6±10.8%). The BA in the SAH+3-AB group showed less corrugation of the tunica elastica interna than that in the SAH-only and SAH+vehicle groups. Staining for poly(ADP-ribosyl)ation was markedly inhibited in smooth muscle and adventitial cells of the BA in the SAH+3-AB group compared with other groups. Conclusions— Inhibiting ADP-ribosylation attenuates cerebral vasospasm after SAH in rabbits, and PARP activation may play an important role in the development of cerebral vasospasm.

The effect of a new immunosuppressive agent, FK-506, on xenogeneic neural transplantation in rodents

This study examines the effect of a novel immunosuppressive agent FK-506 (FK) on the survivability of embryonic (E14) rat ventral mesencephalic tissue after intracerebral grafting to the lateral ventricle of adult mice. The recipient mice were given FK in doses of 10 mg/kg or 1 mg/kg for 2 weeks postgrafting, at which time they were sacrificed and histologically processed except for one group of animals on the high dose (10 mg/kg). In this group most animals died from side effects of the drug during the following days. Only the mice receiving the high dose of FK displayed healthy grafts without signs of rejection.

Detection of Lipid Peroxidation and Hydroxyl Radicals in Brain Contusion of Rats

To examine the relationship between the free radicals and brain tissue damage, we investigated the intensity of brain hydroxyl (OH) radical generation and lipid peroxidation in the rat contusion injury model. A unilateral contusion was induced by a weight-drop method. All rats were decapitated six hours after the injury, and brain samples were taken from three portions (core, peripheral, and distal) to examine the specific gravity as an indicator of brain edema, generation of OH using an electron paramagnetic resonance spectrometer (EPR), and malondialdehyde (MDA) and 4-hydroxyalkenals production. Analysis of the specific gravity revealed cerebral edema on the ipsilateral side in the injured group. The signal intensity of EPR in the core and peripheral portions in the contusion group was significantly higher than that in the distal portion of the contusion group and that of all portions in the control animals. No significant difference was observed between the core and peripheral portions of the contusion group. The MDA and 4-hydroxyalkenals production was significantly higher in the core and peripheral portions than in the distal portion of the contusion group and that of all portions of the control group. The degree of posttraumatic brain edema was closely correlated with the increase of DMPO-OH adduct, MDA, and 4-hydroxyalkenals. These results support the current concept that free radical production following traumatic brain injury may induce lipid peroxidation and may be the direct cause of edema formation.

Long-term outcome in surgically treated spina bifida cystica

This report describes the long-term operative outcome of 72 patients with spina bifida cystica. The period of follow-up was between 4 and 20 years. In our series, 17 patients died, with the mortality rate increasing as the lesions were more rostral. All cases involving only a meningocele are living without handicap. The cases of spina bifida cystica with hydrocephalus had higher morbidity and mortality when compared to those without hydrocephalus. We conclude that the rostro-caudal location, the content of the sac, and whether there is associated hydrocephalus are important factors influencing the long-term prognosis of spina bifida cystica.