Dumbbell-shaped jugular foramen schwannoma

The authors present a case of dumbbell-shaped schwannoma arising from the vagus nerve. A 40-year-old woman was admitted with a 3-month history of hearing loss on the left ear without vertigo. Neuro-otological examinations revealed retrocochlear deafness with abnormal left vestibular function. Magnetic resonance imaging revealed a dumbbell-shaped tumor of the jugular foramen. The tumor was removed through a cervical-transmastoid approach using Cavitoron ultrasonic surgical aspiration. Two months after the operation, the patient's hearing loss had improved, although she still had some aspiration of saliva and hoarseness.

Suppression of acute experimental allergic encephalomyelitis in Lewis rats with a mycophenolic acid derivative

Oral administration of ethyl O-[N-(p-carboxyphenyl-carbamoyl]-mycophenolate (CAM), a derivative of mycophenolic acid (MPA) and an inosine monophosphate dehydrogenase inhibitor, dose-dependently suppressed acute experimental allergic encephalomyelitis in Lewis rats without exerting any serious adverse effects. A daily dose of 50 mg/kg of CAM almost completely abolished both the clinical disease and the inflammation in the CNS. In the CAM-treated rats, a weight loss and fluctuations of peripheral lymphocyte subsets were minimized. The CAM treatment was effective when started at the time of sensitization but ineffective when deferred till day 10. Furthermore, CAM reduced the percentage of CD4+CD45RC- cells in the peripheral blood. The only detectable adverse effect was moderate anemia but it was rapidly improved after withdrawal of the drug. This drug could be a useful adjunct for the long-term immunosuppressive therapy for inflammatory diseases of the CNS.

Dissociation of 99mTc-ECD and 99mTc-HMPAO distributions in herpes simplex encephalitis

In herpes simplex encephalitis (HSE), the authors noted an evident dissociation between the 99mTc-ethyl cysteinate dimer (ECD) and 99mTc-d,l-hexamethyl-propylene-amine oxime (HMPAO) single photon emission computed tomographies (SPECTs). The patient was a 5-year-old boy with diffuse type of pontine glioma, which was treated with hyperfractionated radiotherapy. Two weeks after the completion of radiation therapy, a lesion suggesting that of HSE was noted in the right fronto-temporal region on magnetic resonance images. 99mTc-HMPAO SPECT showed an increased accumulation of the tracer in this lesion. On the 99mTc-ECD dynamic SPECT, an exaggerated accumulation of the tracer was noted within 80 s of administration, followed by a rapid drop in the accumulation, resulting in a low accumulation in 10 min. It was assumed that this dissociation was due to the different mechanisms to trap HMPAO and ECD in the brain tissue.

Aneurysms located at the horizontal segment of the anterior cerebral artery or the middle cerebral artery

Aneurysms at the horizontal segment of the middle cerebral artery or anterior cerebral artery are relatively rare. The characteristics of 13 cases were analyzed retrospectively. Six of the 13 cases had multiple aneurysms, nine had aneurysmal rupture, and three of these nine were complicated by intracerebral hematoma. Neck clipping of the aneurysm was performed in 11 cases and four developed new cerebral infarction in the territory of the perforating arteries. Overall mortality and morbidity was 15% and 38%, respectively. The outcome for patients with aneurysms at these sites was evidently poorer than for those with aneurysms at other sites.

Protein kinase C in focal ischemic rat brain: dual autoradiographic analysis of [14C]iodoantipyrine (IAP) and [3H]phorbol-12,13-dibutyrate (PDBu)

Protein kinase C (PKC) activity was measured in rat brain with 2 h of middle cerebral artery (MCA) and common carotid artery (CCA) occlusion, using dual autoradiography of [14C]iodoantipyrine (IAP) and [3H]phorbol-12,13-dibutyrate (PDBu). In the ischemic brain, it required more than 120 min of incubation to obtain a plateau in PDBu binding. In contrast, the binding of PDBu in non-ischemic brain reached a plateau with incubation for 60 min. This delay of PDBu binding in the ischemic brain suggests that the affinity of this ligand is reduced due to a change in structure of the cell membrane caused by ischemia. PDBu binding in the ischemic brain increased significantly compared to the non-ischemic brain. This finding provides further evidence that excessive activation of PKC in the ischemic brain may play an important role in ischemic neuronal damage.

Glial cyst in the thalamus with intracystic hemorrhage--case report

A 19-year-old female presented with an unusual glial cyst of the thalamus that caused development of acute hydrocephalus due to hemorrhage and manifested as headache and fainting attacks. Computed tomography showed a large cystic mass lesion in the left thalamus with intracystic hemorrhage. The cyst was subtotally removed. Microscopic examination revealed mild gliosis with marked hemosiderin deposits. The inner surface of the cystic wall lacked an epithelial lining. The diagnosis was glial cyst. Magnetic resonance (MR) imaging 2 months after surgery showed a residual cyst in the left thalamus. However, after 12 months she was asymptomatic, neurologically intact, and MR imaging showed no regrowth of the cyst. Treatment of glial cyst must provide sufficient communication between the cyst and the cerebral ventricles rather than attempt total removal of the cyst, which may present a considerable challenge.

Sequential changes in cerebrovascular reserve capacity in three-vessel occlusion rats

To understand the pathophysiology of hemodynamic compromise, we evaluated the cerebrovascular reserve capacity of a cerebral hemisphere in rats with 3-vessel occlusion (3VO). The bilateral vertebral and left common carotid arteries were occluded in Wistar rats. Sequential changes in local cerebral blood flow (LCBF) and local cerebral plasma volume (LCPV) were measured by [14C]iodoantipyrine and [14C]dextran autoradiography, respectively. There was no significant difference in LCBF between 3VO and control rats at rest. After acetazolamide administration, however, an increase of LCBF in the left hemisphere was less significant compared to that in the right side in the 3VO rats. The left and right ratio was 0.67 +/- 0.15 (P < 0.05) in the parietal cortex and 0.70 +/- 0.10 (P < 0.01) in the caudate nucleus. This asymmetrical response to acetazolamide administration gradually corrected by 7 days after 3VO. A significant increase of the LCPV in the ischemic side was observed between day 0 and the 5th day. The 3VO rat is a useful model for studies on the pathophysiology of a hemodynamically compromised state.

[Familial multiple cavernous angioma in the brain and spinal cord]

We reported two patients from the same family underwent operation for neurological symptoms due to vascular lesions that were proved on pathological examination to be cavernous angiomas. Case 1, a 64-year-old woman was admitted to our hospital because of paraparesis. MRI revealed a mass lesion with high signal intensity in T1 and T2 weighted images at T3-4 level. Complete excision was carried out and diagnosis of cavernous angioma was made. Three years later, she experienced a mild headache and dizziness. CT scan demonstrated a subcortical hematoma in the right frontal lobe. Postoperative pathological diagnosis was cavernous angioma. Case 2, a 65-year-old woman (younger sister of case 1) was operated for the tumor of spinal cord, and diagnosed as a cavernous angioma. Two years later, she developed diplopia and ataxic gait. MRI showed multiple cavernous angioma in the brain including pons. Pontine lesion which was responsible for this episode was removed, and diagnosis was a cavernous angioma histopathologically.

[Crystal forms, improvements of dissolution and absorption of poorly water-soluble (R)-1-[2,3-dihydro-1-(2'-methylphenacyl)-2-oxo-5-phenyl-1H-1, 4-benzodiazepin-3-yl]-3-(3-methylphenyl)urea (YM022)]

Polymorphs of (R)-1-[2,3-dihydro-1-(2'-methylphenacyl)-2-oxo-5-phenyl-1H-1,4- benzodiazepin-3-yl]-3-(3-methylphenyl)urea (YM022) were investigated. Two crystalline forms (alpha- and beta-forms) of YM022 were confirmed by powder X-ray diffractometry and differential scanning calorimetry. alpha- And beta-forms were obtained by recrystallization from ethanol and ethanol: water (5:1), respectively. Amorphous YM022 was obtained by spray drying of YM022 methanol solution. Since both crystalline and amorphous YM022 were sparingly soluble in water, solubilization of YM022 by solid dispersion and wet grinding methods were performed. In vitro dissolution study and in vivo absorption study in dogs were carried out using spray-dried solid dispersion, heat-treated solid dispersion and mechanical mixture. Spray-dried solid dispersion and heat-treated solid dispersion showed enhanced bioavailability, whereas mechanical mixture showed no improvement.

A comparative study of acute and chronic diseases induced by two subgroups of Theiler's murine encephalomyelitis virus

Theiler's murine encephalomyelitis viruses (TMEV) are divided into two subgroups on the basis of their different biological activities. The GDVII strain produces acute polioencephalomyelitis in mice, whereas the DA strain produced demyelination with virus persistence in the spinal cord. A comparative study of GDVII and DA strains suggested that low host immune responses are responsible for the development of acute GDVII infection and that the persistence of infected macrophages plays a crucial role in the development of chronic white matter lesions in DA infection. All 78 mice infected with GDVII died or became moribund by day 13, while none of 54 mice infected with DA died. In the acute stage, the distribution of viral antigens in the central nervous system (CNS) tissue was similar in both GDVII and DA infections, although the virus titer was higher in GDVII infection. In DA infection, a substantial number of T cells were recruited to the CNS on day 6 when they were virtually absent in GDVII infection. The titer of neutralizing antibody was already high on day 6 in DA infection but was negligible in GDVII infection. Development of chronic paralytic disease from day 35 of the DA infection was accompanied by focal accumulation of viral antigen-positive macrophages in the spinal white matter. In addition, whiter matter lesions comparable to those in chronic DA infection were induced in the spinal cord within 7 days after intracerebral injection of DA-infected murine macrophages.

[A case of Jefferson fracture treated with the Sof'wire cable system method of fixation]

Jefferson fracture is a very rare disease which occurs in only 2-13% of all cervical spinal fracture cases and in only 1.3% of total spinal fracture cases. A combination of an atlas-axis fracture occurs relatively frequently and with a higher incidence of neurological morbidity than isolated fractures. However, a Jefferson fracture, which is an isolated C-1 fracture, occurs very rarely. A 58-year-old woman was involved in a traffic accident and admitted to our hospital. She had a large scalp laceration in the parietal region and complained of nuchal pain. Neurological examination revealed nothing abnormal. A cervical x-p (lateral view) revealed no abnormal findings, but an open-mouth view revealed an 8 mm displacement (in total) in the lateral mass of the atlas. A cervical CT revealed a Jefferson fracture. Crutchfield traction was performed for 9 days followed by external immobilization with a halo-vest to allow the patient to be ambulatory quickly. A posterior occipitocervical fusion was performed with an iliac bone autograft using the Sof'wire Cable system for late cervical stability and reducing the period of rigid external immobilization. The postoperative state was uneventful. The halo-vest was removed 10 weeks after surgery. An x-p obtained 3 months postoperatively showed good stability of the cervical spine. The Sof'wire Cable system proved to be very useful.

Effect of plant phenolics on the formation of the spin-adduct of hydroxyl radical and the DNA strand breaking by hydroxyl radical

The effect of plant phenolics, including flavonoids and green tea polyphenolics, on hydroxyl radical was examined by a common method using an electron spin resonance (ESR) technique with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trapping agent. The intensity of the ESR signals of DMPO-OH adduct formed by the interaction of DMPO with Fenton reagent was reduced in the presence of each phenolic in a dose-dependent manner. However, the decrease in the intensity of the signals was due partly to the enhanced disappearance of the spin adduct by the phenolics, as has been previously shown. This spin trapping method was unreliable for evaluation of the effect of the phenolics against hydroxyl radical. Hydroxyl radical induced-DNA single-strand breaks may be a better index for evaluation of the activity of the phenolics regarding hydroxyl radical. The effect of the phenolics on DNA single-strand breaks induced by Fenton reagent was examined. While sesamol and esculetin were inhibitory, most polyphenolics, especially (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG), were rather stimulatory. The results indicate that sesamol and esculetin scavenged hydroxyl radical, and EGC and EGCG generated hydroxyl radical under the conditions where hydroxyl radical was generating.

Relationship between gelation rate of controlled-release acetaminophen tablets containing polyethylene oxide and colonic drug release in dogs

PURPOSE

We hypothesized that sufficient gelation of orally administered hydrophilic matrix tablets before they reach the colon could, as a result of continuous erosion of the gelated matrix, prevent the decrease in colonic drug release which normally occurs here. The purpose of this study was to elucidate the effect of gelation of hydrophilic matrices containing polyethylene oxide on colonic drug release in dogs using controlled-release (CR) acetaminophen tablets.

METHODS

Two types of CR tablets were prepared, a slow gelling tablet (SG) and a rapid gelling tablet (RG) containing an extra highly water soluble filler. In vitro and in vivo performance were examined.

RESULTS

SG and RG showed similar drug release behavior in vitro. In oral administration to dogs, the two formulations showed similar gastrointestinal transit, reaching the colon within 2-4 h after oral dosing. Further, they showed similar maximum plasma levels (Cmax) and time to Cmax (Tmax). In contrast, however, the two tablets produced different plasma levels from 2 h post-dosing, with plasma levels of RG higher than those of SG and with smaller individual variation. Directly observed colonic drug release behavior of RG was similar to in vitro drug release, whereas that from SG was suppressed.

CONCLUSIONS

Colonic drug release is closely related to the gelation of hydrophilic matrix, and rapid gelation provides continuous in vivo drug release.

[Posttraumatic pseudoaneurysm of the middle meningeal artery: a case report]

An epidural hematoma associated with posttraumatic pseudoaneurysm of the middle meningeal artery is a very rare clinical entity. Only 31 such cases have been reported in the literature. A 54-year-old man was admitted with lethargy and right hemiparesis. A skull X-ray film revealed a linear fracture in the left parietal and temporal bone, extending to the base of the skull. A brain CT scan disclosed an acute epidural hematoma over the left cerebral hemisphere, contusional hematoma in the right frontal lobe and thalamus, and subarachnoid hemorrhage in the left Sylvian fissure. During an emergency craniotomy a large epidural hematoma was evacuated and external decompression was performed. Angiography, which was performed about one month after the head injury, revealed an aneurysm of the middle meningeal artery. The aneurysm was removed to avoid delayed rupture at the time of cranioplasty. Histological diagnosis was pseudoaneurysm. We discussed the pathogenesis of a pseudoaneurysm of the meningeal artery and the necessity to pay attention to the presence of a pseudoaneurysm when an active bleeding point is not observed during surgery of the epidural hematoma.

[Aneurysm surgery using temporary occlusion under SEP monitoring]

Premature rupture of a cerebral aneurysm during operation is a serious hazard. Temporary occlusion of intracranial arteries has emerged as a valuable technical adjunct in the management of intracranial aneurysms. Twenty-five patients (from a group of 43 consecutive aneurysm patients treated during a 13-month period) underwent elective temporary arterial occlusion under somatosensory evoked potential (SEP) monitoring. Median nerve SEPs were used during 19 ICA and MCA aneurysm operations, while posterior tibial SEPs only were used in 7 patients with aneurysm of the ACA. Amplitude of the N20 or P40 was evaluated. A decrease in amplitude more than 50% when compared to baseline value was defined as a significant SEP change. In 11 patients of the 25 cases, SEP changes were observed. Temporary occlusion was applied to the proximal portion of the internal carotid artery 10 times, to the M1 portion of the middle cerebral artery 5 times, to the M1-M2 complex 5 times, to the A1 portion of the anterior cerebral artery 9 times, and to the A2 - A3 once. Of the 26 clipping (25 patients), 12 had SEP alterations, 14 had no SEP changes. Temporary occlusion was released within 3 minutes after disappearance of N20 (or P40) in all the patients with SEP changes except one. Nine of these 11 patients showed complete recovery of SEP and two showed partial recovery. Patients with partial recovery of SEP were associated with postoperative new neurological deficit, which was transient in one of them. There was a correlation between changes in SEP and post operative outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary position upbeat nystagmus localizing value

Primary position upbeat nystagmus has been associated predominantly with lesions of the midbrain, midline cerebellum, and lower brainstem. However, the precise localization still remains unclear. We report one case of primary position upbeat nystagmus in which magnetic resonance imaging showed probable bilateral lesions of the prepositus hypoglossi nuclei. Morphological and physiological studies have shown that this nucleus plays important roles in vertical eye movements. We conclude that the dysfunction of bilateral prepositus hypoglossi nuclei causes the upbeat nystagmus in our patient.

Accumulation of exogenous 45Ca after middle cerebral artery occlusion in rats

The distribution of exogenous 45Ca in the focal ischemia rat model (middle cerebral artery occlusion) was studied using 45Ca autoradiography. High 45Ca accumulations were observed in the frontal cortex and caudate-putamen corresponding with morphological damage shown by HE staining. Regional 45Ca concentrations were calculated from the optical density on the 45Ca autoradiograms. Rapid uptake of 45Ca in the ischemic brain occurred during the first 5 hours, and continued more slowly between 5 and 24 hours after ischemia. The area of 45Ca accumulation was also expanded between 5 and 24 hours. An area of low 45Ca concentration around the area of high accumulation developed 5 hours after ischemia, which presumably accumulated 45Ca between 5 and 24 hours after ischemia. The lower concentration of 45Ca in the periphery of ischemia may result from: 1) a decrease in the total amount of calcium due to narrowing of extracellular space accompanied by cytotoxic edema, and 2) delayed accumulation of exogenous 45Ca due to reduced clearance of extracellular fluid.

[Ossified epidural hematomas: report of two cases]

Two cases of ossified epidural hematomas were reported. Patients were nine and twelve year-old boys. Initially they were both followed up conservatively after injuries. Subsequently they were found on CT scan to have calcifications in the capsules of epidural hematomas which were found four months after injury in one case and twelve days after injury in the other. Both underwent craniotomy and histological ossification was found in the capsules of the hematomas. Epidural hematomas in children are known to ossify, and this condition may prevent natural absorption of epidural hematomas. Therefore, careful follow up of hematomas seems to be mandatory on conservative therapy of epidural hematomas in children.

Effects of fixation and varying target length on the sensitivity of polymerase chain reaction for detection of human T-cell leukemia virus type I proviral DNA in formalin-fixed tissue sections

In this study, the fixation condition most suitable for maintaining the sensitivity of the polymerase chain reaction (PCR) was investigated by using the alpha-tubulin gene sequence, and the PCR procedure most effective for detecting human T-cell leukemia virus type I (HTLV-I) proviral sequences in fixed, embedded tissues of adult T-cell leukemia patients was explored. First, the sensitivity of the PCR targeting a 286-bp alpha-tubulin sequence was studied in tissue sections fixed in several fixatives for various periods at 25 or 4 degrees C. For histological examination, fixation with 10% buffered formalin at a lower temperature for a shorter period was found to be preferable to retain the sensitivity. And the HTLV-I sequence was detected in only 7 of 18 specimens (38.9%) when the 374-bp sequence of the gag region was targeted, but the rate increased to 77.8% (14 of 18 specimens) when the length of the target sequence was reduced to 120 bp within the same region. Therefore, the one-round PCR targeting a shorter sequence is preferable for application of PCR to archival fixed tissue specimens, the fixation condition of which may not be ideal for DNA preservation.

Local cerebral glucose utilisation following acute and chronic bilateral carotid artery ligation in Wistar rats: relation to changes in local cerebral blood flow

The effects on local cerebral blood flow (LCBF) and glucose utilisation (LCGU) of permanent, bilateral carotid artery ligation (BCAL) were studied in conscious Wistar rats. LCBF and LCGU were measured using quantitative autoradiographic 14C-iodoantipyrine and the 14C-2-deoxyglucose (14C-DG) techniques in 24 anatomically discrete regions of the brain. LCBF in the cerebral hemispheres 2.5 h (acute) after BCAL significantly decreased to 25-87% of the sham control, with the exception of the mammillary body. After acute BCAL, there was a heterogeneous accumulation of 14C-DG in the caudate nucleus and cerebral cortices. Only in the lateral geniculate body did LCGU significantly decrease after BCAL. One week (chronic) later, LCBF was significantly decreased in 15 (containing the caudate nucleus and all the cerebral cortices) of 24 structures. LCGU in ten (containing the caudate nucleus and all the cerebral cortices) of 24 structures after chronic BCAL significantly decreased to 66-77% of the sham control, except for regions with neuronal damage in which there was a heterogeneous uptake of 14C-DG. The ratio of LCBF/LCGU in chronic BCAL was unchanged in comparison with values in the corresponding sham-operated group. This model of acute and chronic cerebral ischaemia, with impairment in cerebral circulation and/or glucose metabolism, is expected to become a pertinent tool for the neurophysiologist.

Sequential change of capillary permeability in the rat brain after surgical removal of an experimental brain tumor

Experimental brain tumors were excised from rats for sequential observation of changes in local capillary permeability during the postsurgical period. Experimental brain tumor-bearing rats were prepared by stereotaxic transplantation of cultured tumor cells and the resultant tumor was delineated by administration of a dye. Following excision of the stained tumor by craniotomy, sequential changes in local capillary permeability were quantitatively followed-up by autoradiography, using 14C-amino-isobutyric acid as a tracer. Capillary permeability was enhanced following surgery, reaching a maximum both in the extent and degree on the third day. After undergoing a gradual reduction, it showed a marked increase for the second time in a very small area on the 10th postoperative day. A recurrence of the tumor was responsible for this late but marked increase. For a control group, the caudate nucleus was excised from normal rats, followed by observation of the sequential changes in the local capillary permeability. Due to surgical procedure, capillary permeability reached a maximum both in the extent and degree on the 5th postoperative day (slightly later than in the tumor group). This change in capillary permeability was less pronounced than in the tumor group. The difference in the conditions of surgery--tumor excision and partial excision of a normal brain tissue--appeared to explain this difference. The results of this study indicated that it is more desirable to give water-soluble antineoplastic agents early during the postoperative period for chemotherapy of a malignant brain tumor after surgery.