True aneurysm on the posterior meningeal artery associated with a dural arteriovenous fistula: case report.

BACKGROUND: We report an unusual case of a true dural aneurysm arising from the posterior meningeal artery that fed a symptomatic dural arteriovenous fistula located at the right transverse-sigmoid sinus junction. CLINICAL PRESENTATION: A 29-year-old right-handed white woman presented with aneurysmal dilatation of hypertrophied posterior meningeal artery feeding a partially treated dural arteriovenous fistula. INTERVENTION: The aneurysm, which measured approximately 3 mm in width and 5 mm in length, was located in the intracranial space with a thin-walled dome projecting toward the cerebellum. Its afferent and efferent vessels were identified, secured, and the lesion was excised en bloc. CONCLUSION: A thorough evaluation of all diagnostic studies should be performed for patients with vascular malformations to help identify these or other unusual lesions that may aid in the risk stratification process and management plan.

Rupture of cerebral myxomatous aneurysm months after resection of the primary cardiac tumor.

BACKGROUND: The natural history of cerebral aneurysms derived from metastatic spread of cardiac myxomas is not well known, and their management presents many dilemmas. METHODS: Case report and literature review. RESULTS: An 18-year-old man presented with an intraparenchymal hemorrhage several months after resection of an atrial myxoma. Angiography showed several myxomatous aneurysms, one of which had bled. The patient had a recurrent hemorrhage before undergoing surgical resection. MRI, angiographic, and pathological data are presented for this rare condition. CONCLUSIONS: Myxomatous aneurysms are important entities for neurointensivists to recognize and can present years after diagnosis. Patients presenting with cerebral infarction or hemorrhage of unknown etiology should undergo cardiac imaging to rule out atrial myxoma, as up to 50% of patients with myxomas present initially with stroke.

Progressive multifocal leukoencephalopathy after rituximab therapy in HIV-negative patients: a report of 57 cases from the Research on Adverse Drug Events and Reports project.

Rituximab improves outcomes for persons with lymphoproliferative disorders and is increasingly used to treat immune-mediated illnesses. Recent reports describe 2 patients with systemic lupus erythematosus and 1 with rheumatoid arthritis who developed progressive multifocal leukoencephalopathy (PML) after rituximab treatment. We reviewed PML case descriptions among patients treated with rituximab from the Food and Drug Administration, the manufacturer, physicians, and a literature review from 1997 to 2008. Overall, 52 patients with lymphoproliferative disorders, 2 patients with systemic lupus erythematosus, 1 patient with rheumatoid arthritis, 1 patient with an idiopathic autoimmune pancytopenia, and 1 patient with immune thrombocytopenia developed PML after treatment with rituximab and other agents. Other treatments included hematopoietic stem cell transplantation (7 patients), purine analogs (26 patients), or alkylating agents (39 patients). One patient with an autoimmune hemolytic anemia developed PML after treatment with corticosteroids and rituximab, and 1 patient with an autoimmune pancytopenia developed PML after treatment with corticosteroids, azathioprine, and rituximab. Median time from last rituximab dose to PML diagnosis was 5.5 months. Median time to death after PML diagnosis was 2.0 months. The case-fatality rate was 90%. Awareness is needed of the potential for PML among rituximab-treated persons.

Phosphorylation of beta-amyloid precursor protein (APP) cytoplasmic tail facilitates amyloidogenic processing during apoptosis.

Secretion and progressive cerebral accumulation of beta-amyloid peptides (Abeta) derived by endoproteolytic ("amyloidogenic") processing of beta-amyloid precursor protein (APP) represent collectively an early and necessary event in the pathogenesis of Alzheimer's disease. We previously demonstrated that secretion of the neurotoxic species Abeta42 increases during staurosporine-induced apoptosis in undifferentiated PC12 cells, in an endocytosis-dependent manner. In the present study, we tested whether phosphorylation of the APP cytoplasmic-tail is contributory to this apoptosis-related increased Abeta-secretory response. We demonstrate that cytoplasmic-tail phosphorylation specifically at amino-acid residue T668 (APP-695 numbering) increases during staurosporine-induced apoptosis, in parallel with activation of the mitogen-activated, proline-directed serine/threonine protein kinase ERK1. We demonstrate additionally that specific ERK inhibition during staurosporine induction, with serum-free conditions, results in down-regulation of APP phosphorylation at T668, together with attenuation of the increased Abeta-secretory response. These results are consistent with APP cytoplasmic-tail phosphorylation at T668 during apoptosis as contributory to increased Abeta42 secretion originating from the endocytotic pathway, likely with cell-line restriction.

The endocytotic pathway is required for increased A beta 42 secretion during apoptosis.

Secretion and progressive cerebral accumulation of beta-amyloid peptides (A beta), which derive by endoproteolytic ('amyloidogenic') processing of beta-amyloid precursor protein (APP), are felt to represent collectively an early and necessary event in the pathogenesis of Alzheimer's disease. APP amyloidogenic processing can occur via secretory or endocytotic pathways, but the relative contribution of these pathways to A beta secretion remains to be established. The effect of apoptosis on amyloidogenic processing and A beta secretion similarly is incompletely understood. We tested the hypothesis that APP processing by the endocytotic pathway represents a stress-related neural cell response, by comparing A beta secretion after induction of apoptosis in PC12 cells transfected either for endocytosis-competent or -deficient APP. Newly prepared adenoviral vectors encompassing targeted mutagenesis of the cytoplasmic tail YENP tetrapeptide sequence, which serves as the principal APP internalization signal, were used to express endocytosis-deficient holoprotein. We report that the endocytotic pathway is required for the generation and secretion of A beta 42, and that secretion of this neurotoxic peptide increases significantly during apoptosis. We demonstrate additionally that more A beta 40 apparently is generated in secretory compartments during apoptosis when APP processing by the endocytotic pathway is impaired.

Surgical management of a ruptured posterior choroidal intraventricular aneurysm associated with moyamoya disease using frameless stereotaxy: case report and review of the literature.

OBJECTIVE AND IMPORTANCE: Prevention of rebleeding is the most important aspect of the management of hemorrhagic moyamoya disease, because rebleeding causes significant morbidity and mortality. CLINICAL PRESENTATION: A 26-year-old male patient with a history of moyamoya disease since the age of 3 years and multiple strokes was in a semicomatose state at presentation. He was found to have intraventricular and periventricular hemorrhages abutting the atrium of the right ventricle. His hospital course was complicated by a second hemorrhage. Both bleeding events were believed to be secondary to a ruptured right lateral posterior choroidal aneurysm. INTERVENTION: The aneurysm was excised and revealed histopathology consistent with a true saccular aneurysm. Frameless stereotactic guidance was used during surgery to minimize damage to collateral vessels and to shorten the surgical corridor. CONCLUSION: The management of hemorrhagic moyamoya disease should be modified based on the source of hemorrhage and its relation to a specifically located aneurysm. In the case of aneurysms arising from the choroidal artery, the general belief is that most of these represent pseudoaneurysms and have a tendency to regress spontaneously. Because of the rebleeding risk, we recommend early intervention in treating ruptured intracranial aneurysms using the least invasive surgical techniques.