In vivo cerebrovascular effects of cocaine- and amphetamine-regulated transcript (CART) peptide.

Cocaine- and amphetamine-regulated transcript (CART) and its associated peptides have been implicated in a number of physiologic processes including modulation of the hypothalamo-pituitary-adrenal (HPA) axis and cardiovascular regulation. Recently, we reported that in isolated cerebral arterioles, CART peptide (CARTp) acts directly to produce endothelium-dependent constriction via the endothelin signaling pathway. We used the rat closed cranial window model to determine the in vivo effects of CARTp on pial arteriolar diameter. Intravenous administration of 30 microg/kg CARTp produced a significant pressor effect and constriction of pial arterioles. The pressor response to systemic CARTp was blocked by the beta-adrenergic receptor antagonist propranolol (2 mg/kg IV). Direct application of 0.1 nM-1 microM CARTp to pial arterioles produced a dose-dependent and long-lasting constriction to approximately 88% of baseline diameter. The constriction response to topically applied 100 nM CARTp was blocked by both the endothelin A (ETA) receptor antagonist BQ-123 (10 microM) and the inhibitor of endothelin-converting enzyme, phosphoramidon (100 nM). These results demonstrate for the first time that CARTp constricts cerebral vessels in vivo, an action mediated by its effects on the endothelin system, specifically via activation of ETA receptors. This supports the notion that CARTp plays a physiologic role in cerebrovascular regulation, particularly during times of HPA axis activation.

Pain relief after cervical ganglionectomy (C2 and C3) for the treatment of medically intractable occipital neuralgia.

Occipital neuralgia (ON) presents a diagnostic challenge because of the wide variety of symptoms, surgical findings, and postsurgical outcomes. Surgical removal of the second (C2) or third (C3) cervical sensory dorsal root ganglion is an option to treat ON. The goal of this study was to evaluate the short-term and the long-term efficacy of these procedures for management of cervical and occipital neuropathic pain. Twenty patients (mean age 48.7 years) were identified who had undergone C2 and/or C3 ganglionectomies for intractable occipital pain and a retrospective chart review undertaken. Patients were interviewed regarding pain relief, pain relief duration, functional status, medication usage and procedure satisfaction, preoperatively, immediately postoperative, and at follow-up (mean 42.5 months). C2, C3 and consecutive ganglionectomies at both levels were performed on 4, 5, and 11 patients, respectively. All patients reported preoperative pain relief following cervical nerve blocks. Average visual analog scale scores were 9.4 preoperatively and 2.6 immediately after procedure. Ninety-five percent of patients reported short-term pain relief (<3 months). In 13 patients (65%), pain returned after an average of 12 months (C2 ganglionectomy) and 8.4 months (C3 ganglionectomy). Long-term results were excellent, moderate and poor in 20, 40 and 40% of patients, respectively. Cervical ganglionectomy offers relief to a majority of patients, immediately after procedure, but the effect is short lived. Nerve blocks are helpful in predicting short-term success, but a positive block result does not necessarily predict long-term benefit and therefore cannot justify surgery by itself. However, since 60% of patients report excellent-moderate results, cervical ganglionectomy continues to have a role in the treatment of intractable ON.

Modified orbitozygomatic craniotomy for craniopharyngioma resection in children.

OBJECT: In this study, the authors evaluated the efficacy and safety of modified orbitozygomatic craniotomy for resection of craniopharyngioma in children. METHODS: A prospective, institutional review board-approved database was retrospectively reviewed for pediatric patients undergoing craniopharyngioma resection performed by a single surgeon. RESULTS: Ten patients underwent craniopharyngioma resection surgery between July 2000 and January 2006 (4 girls and 6 boys, ages 1.5-17 years). Nine patients presented to the authors' institution, and 1 patient was referred after surgery and radiation therapy were administered elsewhere. Nine patients presented with visual field deficits (2 with unilateral or bilateral light perception only) and 5 with endocrine dysfunction. Eight patients had large tumors that significantly displaced the optic chiasm and hypothalamus. All patients underwent a modified frontotemporal orbitozygomatic osteotomy in a single piece. The lamina terminalis was opened in 4 patients with third ventricular extension. One patient required a staged transsphenoidal operation to remove residual tumor in the sella turcica, and 1 patient underwent a contralateral subtemporal approach to resect a daughter lesion in the prepontine cistern. Complete radiographic resection was achieved in all patients. Follow-up averaged 55 months (range 12-95 months). Vision was improved in 8 patients and remained stable in 2. All patients had postoperative endocrine dysfunction. One patient experienced transient cranial nerve IV palsy and 1 suffered a small caudate stroke 5 months after surgery without sequelae. Two patients experienced polyphagia and weight gain without other symptoms of hypothalamic dysfunction. There were no other new neurological deficits. CONCLUSIONS: Modified orbitozygomatic craniotomy provides excellent exposure of the suprasellar region with minimal brain retraction, allowing complete resection of craniopharyngiomas with good visual and neurological results.

Successful ventricle to direct heart shunt placement as a salvage cerebrospinal fluid diversion technique. Case report.

The authors report a complex case in a 35-year-old woman who underwent shunt placement at birth for myelomeningocele. She had previously undergone more than 30 shunt revisions, with placement of the distal catheter in the peritoneum multiple times, and also in the pleura, the gall bladder, and the upper venous system. All shunts had failed and the possible placement sites were now anatomically hostile. A median sternotomy was performed as the next option. The catheter was placed directly into the appendage of the right atrium and secured with a pursestring suture. One month postoperatively, the patient presented with a large pericardial effusion after the distal catheter migrated out of the atrium and into the pericardial space. A repeat sternotomy was performed to drain the pericardial CSF collection. The catheter was reinserted into the atrial appendage, and a tunnel was created in the atrial wall to fix the device more securely. At 1 year postoperatively, the patient had no further symptoms of shunt obstruction or cardiac tamponade, and imaging studies suggested that the shunt system was functional. The authors report the first successful ventricle to direct heart shunt in an adult.

A new model of cortical stroke in the rhesus macaque.

Primate models are essential tools for translational research in stroke but are reportedly inconsistent in their ability to produce cortical infarcts of reproducible size. Here, we report a new stroke model using a transorbital, reversible, two-vessel occlusion approach in male rhesus macaques that produces consistent and reproducible cortical infarcts. The right middle cerebral artery (distal to the orbitofrontal branch) and both anterior cerebral arteries were occluded with vascular clips. Bilateral occlusion of the anterior cerebral artery was critical for reducing collateral flow to the ipsilateral cortex. Reversible ischemia was induced for 45, 60, or 90 mins (n=2/timepoint) and infarct volume and neurologic outcome were evaluated. The infarcts were located predominantly in the cortex and increased in size with extended duration of ischemia determined by T(2)-weighted magnetic resonance imaging . Infarct volume measured by 2,3,5-triphenyl tetrazolium chloride and cresyl violet staining corroborated magnetic resonance imaging results. Neurologic deficit scores worsened gradually with longer occlusion times. A subset of animals (n=5) underwent 60 mins of ischemia resulting in consistent infarct volumes primarily located to the cortex that correlated well with neurologic deficit scores. This approach offers promise for evaluating therapeutic interventions in stroke.