No abstract

Apolipoprotein E (apoE) is known to be a risk factor for the incidence of Alzheimer's disease (AD). In addition, vitamin E has been reported to have a role in the treatment of AD. We examined the potential interrelationship between vitamin E and apoE in brain. As the first step, we determined the concentrations of a-tocopherol in selected brain regions of apoE-deficient mice at different ages. The mice were fed normal rodent chow. All regions of the brain in apoE-deficient mice contained less a-tocopherol than control samples at 2.5 months of age, the initial time of study. This trend continued for 9.5 months for most regions except the spinal cord and cerebellum. Tocopherol levels in these latter regions of apoE-deficient animals increased to control levels during the study. Serum a-tocopherol and cholesterol levels were high in the apoE-deficient animals; however, the CNS cholesterol levels were the same in apoE-deficient and control mice. This suggests that 1) the decline in brain a-tocopherol in apoE deficiency is not due to overall alterations in lipid metabolism; and 2) the processing of a-tocopherol in brain follows a separate pathway than that of cholesterol. Subcellular concentrations of a-tocopherol were unaltered by apoE deficiency indicating that intracellular handling of tocopherol is not affected by apoE. ApoE may be an important protein controlling vitamin E levels in specific brain regions. Further understanding of the interactions between apoE and vitamin E could be important in the appropriate use of vitamin E in AD. V V C 2006 Wiley-Liss, Inc.

Introduction: The posterior fossa in a child poses a considerable challenge to the neurosurgeon. MRI-guided surgery allows for real time interaction between imaging and the neurosurgeon, not permitted by frameless stereotaxy, and with higher resolution than ultrasound or CT. Materials and Methods: The University of Minnesota 1.5 T Phillips interventional MRI was used. From 1997 to 2000, nine posterior fossa intraoperative magnet cases out of eleven were pediatric. The mean age was 6.4 years and the median age 7. Seven midline craniotomies were performed, of which three were re-operations. Two were burr hole placements, one for cyst aspiration and P32 instillation, and the other for tumor biopsy. Results: Two tumors were predominantly in the fourth ventricle, four in the cerebellum, two in the brainstem, and one in the prepontine cystern. Four tumors were juvenile pilocytic astrocytomas, two were anaplastic astrocytomas, and one each was ependymoma, craniopharyngioma cyst, and medulloblastoma. Four patients had complete radiologic resection. Two had maximal resections limited by vital structures. P32 instillation and tumor biopsy were done in a single pass. Follow-up ranged from 3 months to 1.4 years. The cyst that was aspirated and had P32 instillation remains absent. The two mortalities were in the patients with medulloblastoma and anaplastic astrocytoma. There were no intra-operative mortalities. The other patient with anaplastic astrocytoma progressed. The remainder had stable imaging. Conclusion: MRI-guided surgery results in improved resection imaging and real-time needle guidance in tumor operations. Its value could lie in low-grade lesions, where maximal resection is most beneficial.

Neurocutaneous melanosis (NM) coexisting with the Dandy-Walker complex (DWC) is a rare condition, with fewer than 15 cases reported in the literature. The authors present a case of an infant with NM and DWC suffering from progressive brainstem compression following ventriculoperitoneal (VP) shunt placement for hydrocephalus. This 1-year-old boy with congenital melanocytic nevi had met normal developmental milestones until the age of 11 months, when he began regressing in ambulation and language function. Intractable vomiting had developed 1 week later. Magnetic resonance (MR) imaging of the brain revealed DWC with hydrocephalus, and spinal MR images demonstrated a proliferative process within the meninges, consistent with NM. The patient underwent right frontal VP shunt placement resulting in immediate symptom relief, but 3 weeks later became irritable, increasingly lethargic, unable to pull to stand, and unable to tolerate solid food without choking. Due to these symptoms and intractable vomiting, the patient presented to the authors' institution. Brain MR imaging revealed a new-onset diffuse cystic process with anterior and posterior brainstem compression, marked kinking of the cervicomedullary junction, melanocyte pigmentation of the left temporal lobe, diffuse leptomeningeal enhancement, and no evidence of hydrocephalus. Consistent with these imaging findings, the degree of brainstem involvement upon gross visualization predictably deterred resection attempts beyond those necessary for biopsy. Pathological examination revealed diffuse melanocytosis, and the family decided not to pursue aggressive measures postoperatively. This report indicates the potential for rapid intracranial manifestation of diffuse melanocytosis in NM patients. Although the prognosis is poor, early neurosurgical involvement in these patients may provide tissue diagnosis and the potential for decompression if the process is caught early in its course.