The relationship between changes in Ca2+-adenosine triphosphatase (ATPase) activity and plasma membrane damage was histochemically studied by enzymatic electron microscopy in rat brains with and without superoxide treatment. The brains were obtained from male Wistar rats after decapitation, and the control brains were examined immediately. Brains not treated with superoxide were incubated at 20°C for 3, 6, or 12 hours. The superoxide-treated brains were immersed in a hypoxanthine-xanthine oxidase system for 20, 60, or 120 minutes. Ca2+-ATPase activity in the cerebral cortex and hippocampal CAI was studied by the lead citrate method. Control brains showed Ca2+-ATPase activity in the membrane of the nerve cell body and dendrites, the basement membrane of endothelial cells, and the erythrocyte membrane. In untreated brains, enzymatic activity gradually decreased but was still detected after 12 hours. In those treated with superoxide, enzymatic activity gradually decreased but was still observed after 120 minutes in fragments of the plasma membrane. These findings show that the plasma membrane is more affected by treatment with superoxide than by decapitation itself, and that plasma membrane damage precedes the disappearance of Ca2+-ATPase activity. Residual Ca2+-ATPase activity does not necessarily imply reversibility of cerebral ischemia.
The effects of interstitial magnetic induction hyperthermia alone and in combination with chemotherapy were evaluated in a rabbit brain tumor model. VX2 carcinoma cells were implanted intracerebrally in 28 rabbits. The animals were divided into four groups of seven each, and the experimental protocols were started on the 7th day after inoculation. Group 1 underwent hyperthermia alone by means of implantation of a needle (Fe-Pt alloy) in the tumor, which was maintained at 45°C for 30 minutes. Group 2 received 12.5 mg/kg ACNU intravenously via a lateral ear vein. In Group 3, 10 minutes after injection of ACNU, hyperthermia was induced in the same manner as in Group 1. Group 4 were controls and received no treatment. The four groups were evaluated and compared in terms of length of survival and pathological features of their brain tumors at the time of death. The mean survival times of Groups 1, 2, 3, and 4 were 14.7, 14.7, 17.3, and 12.3 days, respectively. Statistically significant differences were found between Groups 1 and 4 and between Groups 3 and 4, but not between Groups 1 and 2. Pathological findings in the hyperthermia group included necrosis around the implant. The tumor cells surrounding the necrotic area had degenerated and the vessels were dilated and static. Thus, in this rabbit brain tumor model, hyperthermia alone was significantly superior to no treatment, and combined treatment with hyperthermia and chemotherapy was more effective than either treatment alone.
To clarify the pathophysiology of normal pressure hydrocephalus (NPH) after subarachnoid hemorrhage, the authors measured cerebral blood flow (CBF), cerebral oxygen metabolic rates (CMRO2), the cerebral oxygen extraction fraction (OEF), and cerebral blood volume (CBV) in eight normal volunteers, six SAH patients with NPH, and seven patients without NPH by 15O-labeled gas and positron emission tomography (PET). In the NPH group, PET revealed a decrease in CBF in the lower regions of the cerebral cortex and a diffuse decrease in CMRO2. The decrease in CBF in the lower frontal, temporal, and occipital cortices was significantly greater in the NPH than in the non-NPH group. Reduction of CMRO2 was also more extensive in the NPH group, and both CBF and CMRO2 were more markedly decreased in the lower frontal region. OEF was increased in all areas in both of the patient groups, but the increase was not significant in most areas. CBF, CMRO2 and OEF did not significantly differ between the non-NPH group and the normal volunteers. There was no significant difference in CBV among the three groups. These results indicate that NPH involves impairment of cerebral oxygen metabolism in the lower regions of the cerebral cortex, particularly in the lower frontal region.
Regional cerebral blood flow (CBF) in eight patients in a persistent vegetative state was measured and compared with that in five healthy volunteers. The patients were classified into three groups: Group 1 (locked-in syndrome) consisted of a single patient, Group 2 (typical vegetative state) of five patients, and Group 3 (prolonged coma) of two patients. CBF was measured early after onset by single photon emission computed tomography with 123I-N-isopropyl-p-iodo-amphetamine and/or 99mTc-hexamethylpropyleneamine oxime. The regions of interest (ROIs) were the bilateral frontal, temporal, parietal, occipital, and cerebellar areas and basal ganglia. The values obtained in these areas were averaged, and the ratio for each ROI [(the value in the ROI/the mean value) × 100] was calculated. “Hyperfrontal distribution” of CBF was found to be rare in both the normal condition and the vegetative state. Higher CBF values were noted in the left than in the right frontal area in four of the five volunteers but in only four of the eight patients. CBF distribution in the frontal lobe was characteristic for each group: Group 1 showed high CBF bilaterally, although the elevation was statistically significant only on the right side, and Group 3 exhibited significantly low values. In Group 2, CBF was variable but, for the most part, within normal limits. Awareness was closely correlated with frontal lobe function and alteration of CBF in the frontal region.
Arteriovenous malformations (AVMs) dramatically alter normal cerebral circulatory dynamics. Clinical and radiographic data from 62 patients were analyzed to determine their impact on total brain blood flow (TBF) measured by single-photon emission computed tomography. 48% of patients presented with hemorrhage and 34% with progressive deficits. 37% had angiographic steal and 21 % developed postoperative hyperemic complications. 40% were under 30 years old, 45% were between 30 and 50 years of age, and 15% were over 50. TBF was less than 70 ml/100 gm/min in 32% of patients, between 70 and 84 ml/100 gm/min in 40%, and greater than 84 ml/l00 gm/min in 27%. Female patients had higher TBF than males; 42% of females but only 17% of males had values greater than 84 ml/100 gm+frsal;min (p < 0.05). A trend toward decreased TBF with advancing age was noted. Intracranial hemorrhage was associated with lower TBF; 47% of patients with hemorrhage and 19% of those without had TBF of <70 ml/ 100 gm/min (p < 0.05). 89% of patients with AVMs less than 5 cm in diameter had TBF of ≤84 ml/100 gm/min, and 65% of those with larger AVMs had similarly low flows (p < 0.05). A trend toward lower TBF was observed in patients with unfavorable outcomes.
Sixty-two patients with radiographically proven intracranial arteriovenous malformations underwent preoperative regional cerebral blood flow measurement with 133Xe single-photon emission computed tomography. Contralateral regions of hypoperfusion were detected in all cases. Steal severity was assessed according to the contralateral steal index [ISteal(c)]. ISteal(c) was <0.7 (severe) in 22 (35%), 0.7-0.8 (intermediate) in 18 (29%), and >0.8 (mild) in 22 (35%). ISteal(c) was more frequently severe or mild in females and more often intermediate in males (p < 0.05). Hyperemic complications were encountered more frequently in patients with intermediate ISteal(c) (p = 0.086). An unfavorable outcome was associated with less severe contralateral steal (p = 0.12). A detailed clinical, radiographic, and hemodynamic profile may help to preoperatively identify patients at high risk for a poor surgical outcome.
The efficacy of cisternal drainage in association with early aneurysmal surgery remains highly controversial. The authors attempted to clarify the indications for this procedure and the proper timing of drainage removal in a series of 205 patients with no evidence of intracerebral hematoma who underwent surgical obliteration of bleeding aneurysms within 72 hours after subarachnoid hemorrhage. The 136 patients in whom cisternal drainage was performed constituted Group A and the remaining 69 patients Group B. The acid-base balance and lactate concentration were measured serially in cisternal cerebrospinal fluid (CSF) and arterial blood of 33 patients. Subarachnoid blood demonstrated by computed tomography (CT) was graded according to the system of Fisher et al. The outcome at 6 months did not differ significantly between Groups A and B among patients of preoperative CT grade 2 and clinical grades I-II. However, among patients of CT grade 3 or clinical grade III, those in Group A had better outcomes. The rates of symptomatic vasospasm in Groups A and B were 39.7% and 40.6%, respectively. However, persistent vasospasm was more frequent in Group B (11.8% vs. 26.1 %), particularly in CT grade 3 patients. Ventricular enlargement was more prevalent in Group A (33% vs. 17%). CSF pH higher than arterial pH after the 7th postoperative day was associated with a poor outcome and was fairly well correlated with a rise in CSF HCO, 3- and a fall in CSF PCO2. CSF lactate increased with clinical deterioration but was not well correlated with preoperative CT findings, total volume of CSF outflow, or prognosis. These results suggest that cisternal drainage is indicated in cases of preoperative CT grade 3 or clinical grade III, and that the drainage tube should be removed as soon as possible if the CSF pH falls below the arterial pH and CSF lactate decreases toward the normal level.
The authors report a newborn girl with a large meningoencephalocele, 18.5 cm in diameter, at the anterior fontanel. She had several accompanying anomalies, including microcephalus, cleft palate, and a uvula bifida. A plain skull x-ray revealed craniolacunia and a computed tomography (CT) scan showed maldevelopment of the cerebrum. The mass was resected, after which the fontanel was noted to bulge. CT demonstrated dilated lateral ventricles. A successful shunting procedure permitted the infant to leave the hospital in good general condition.
A 51-year-old female with an ependymal cyst in the left occipital lobe presented with headache, vomiting, dizziness, and right incomplete homonymous hemianopsia. Following a cyst-ventricular communication and cyst-peritoneal shunting procedure, the visual field loss improved markedly. On the basis of the visual field symptoms, computed tomographic findings, and intraoperative observations, the cyst was considered to have developed in the vicinity of the body and posterior horn of the left lateral ventricle, extending to the left occipital lobe.
The authors describe the case of a 37-year-old female with a symptomatic epithelial cyst in the cerebellopontine angle, which is extremely rare. The cyst caused trigeminal neuralgia, which completely disappeared following its removal. The histological diagnosis was choroidal epithelial fluid-filled cyst. The wall of the cyst consisted of a single layer of epithelial cells with microvilli and a basement membrane.
A 16-year-old girl with a large, ruptured arteriovenous malformation (AVM) of the corpus callosum was studied by computed tomography and angiography. The relatively large nidus of the AVM was located mainly in the anterior portion of the corpus callosum, and there was a smaller nidus in the splenium. She also had a persistent primitive left trigeminal artery (PTA). This is the first reported case of an AVM with extensive callosal involvement associated with a PTA. She underwent radiation therapy and remained asymptomatic for 2 years thereafter.
The authors report a case of histologically confirmed cerebral arteriovenous malformation (AVM) in which cerebral angiography demonstrated only mass effect. Magnetic resonance (MR) imaging yielded valuable preoperative diagnostic information. T1 and T2-weighted MR imaging demonstrated an area of mixed signal intensity with a mossy appearance, evidence of a hematoma around the mass, and spots of zero signal intensity within the mass, suggesting the presence of vessels with accelerated blood flow.
A female who had had no previous cerebrovascular events suffered a subarachnoid hemorrhage and was referred to our hospital. Angiography revealed an anterior communicating artery aneurysm and bilateral occlusion of the middle cerebral artery at its origin. She exhibited mild ischemic symptoms after clipping of the aneurysm, possibly as a consequence of disturbance of the collateral blood flow during surgery. This is the third such case reported in the literature.
Meningiomas are often described as hormone-dependent because of their preponderance in females and their tendency to clinically manifest during or after pregnancy. We describe a case of meningioma that grew rapidly during two pregnancies over a 2-year period. The tumor's rapid growth was confirmed by high-resolution computed tomography. Its estimated doubling time was 110 days. The tumor was removed and found to be a benign meningothelial meningioma. The tumor tissue was positive for estrogen receptors (ERs) and progesterone receptors (PRs). In nine cases, including this one, in which ERs and PRs were measured, the positive rate was much higher for PRs than for ERs; only two were positive for ERs. In the case reported here, it is presumed that the growth of the meningioma was influenced by estrogen and/or progesterone binding to receptors, although it is unclear whether one or both hormones was involved.
Benign osteoblastoma is a rare tumor of bone, usually confined to the long bones and vertebrae. Its occurrence in the calvaria is extremely rare. The authors report a case of a temporoparietal lesion in a 29-year-old male. Computed tomography revealed a low-density mass, which was irregularly enhanced by contrast medium. Magnetic resonance imaging demonstrated a mass of low intensity on T1- and high intensity on T2-weighted images. Angiography confirmed the presence of a large epidural mass in the left temporal region. The tumor was excised and the pathological diagnosis was benign osteoblastoma.
A curved ventricular catheter was designed for ventriculoperitoneal shunt procedures. The tip of the catheter can be inserted into the anterior horn along the curvature of the lateral ventricle. To date, it has been applied in 14 cases, all with satisfactory results.