Cellular interactions between axon terminals containing endogenous opioid peptides or corticotropin-releasing factor in the rat locus coeruleus and surrounding dorsal pontine tegmentum.

Recent evidence suggests that certain stressors release both endogenous opioids and corticotropin-releasing factor (CRF) to modulate activity of the locus coeruleus (LC)-norepinephrine (NE) system. In ultrastructural studies, axon terminals containing methionine(5)-enkephalin (ENK) or CRF have been shown to target LC dendrites. These findings suggested the hypothesis that both neuropeptides may coexist in common axon terminals that are positioned to have an impact on the LC. This possibility was examined by using immunofluorescence and immunoelectron microscopic analysis of the rat LC and neighboring dorsal pontine tegmentum. Ultrastructural analysis indicated that CRF- and ENK-containing axon terminals were abundant in similar portions of the neuropil and that approximately 16% of the axon terminals containing ENK were also immunoreactive for CRF. Dually labeled terminals were more frequently encountered in the "core" of the LC vs. its extranuclear dendritic zone, which included the medial parabrachial nucleus (mPB). Triple labeling for ENK, CRF, and tyrosine hydroxylase (TH) showed convergence of opioid and CRF axon terminals with noradrenergic dendrites as well as evidence for inputs to TH-labeled dendrites from dually labeled opioid/CRF axon terminals. One potential source of ENK and CRF in the dorsal pons is the central nucleus of the amygdala (CNA). To determine the relative contribution of ENK and CRF terminals from the CNA, the CNA was electrolytically lesioned. Light-level densitometry revealed robust decreases in CRF immunoreactivity in the LC and mPB on the side ipsilateral to the lesion but little or no change in ENK immunoreactivity, confirming previous studies of the mPB. Degenerating terminals from the CNA in lesioned rats were found to be in direct contact with TH-labeled dendrites. Together, these data indicate that ENK and CRF may be colocalized to a subset of individual axon terminals in the LC "core." The finding that the CNA provides, to dendrites in the area examined, a robust CRF innervation, but little or no opioid innervation, suggests that ENK and CRF axon terminals impacting LC neurons originate from distinct sources and that terminals that colocalize ENK and CRF are not from the CNA.

Spontaneous delayed migration/shortening of the pipeline embolization device: report of 5 cases.

Five patients were found to have spontaneous delayed migration/shortening of their Pipeline Embolization Devices on follow-up angiography. The device migrated proximally in 4 patients and distally in 1 patient. One patient had a subarachnoid hemorrhage and died as a result of migration of the Pipeline Embolization Device, and another patient presented with complete MCA occlusion and was left severely disabled. Mismatch in arterial diameter between inflow and outflow vessels was a constant finding. Migration of the Pipeline Embolization Device was managed conservatively, with additional placement of the device, or with parent vessel occlusion. Obtaining complete expansion of the embolization device by using a longer device, increasing vessel coverage, using adjunctive aneurysm coiling, and avoiding dragging and stretching of the device are important preventive measures. Neurointerventionalists should be aware of this potentially fatal complication and take all necessary preventive measures.

Stent-assisted coiling versus balloon remodeling of wide-neck aneurysms: comparison of angiographic outcomes.

BACKGROUND AND PURPOSE: Stent-assisted coiling and balloon-assisted coiling are 2 well-established techniques for treatment of wide-neck intracranial aneurysms. A direct comparative analysis of angiographic outcomes with the 2 techniques has not been available. We compare the angiographic outcomes of wide-neck aneurysms treated with stent-assisted coiling versus balloon-assisted coiling. MATERIALS AND METHODS: A retrospective review was conducted on 101 consecutive patients treated at our institution, 69 with stent-assisted coiling and 32 with balloon-assisted coiling. Two multivariate logistic regression analyses were performed to determine predictors of aneurysm obliteration and predictors of progressive aneurysm thrombosis at follow-up. RESULTS: The 2 groups were comparable with respect to all baseline characteristics with the exception of a higher proportion of ruptured aneurysms in the balloon-assisted coiling group (65.6%) than in the stent-assisted coiling group (11.5%, P < .001). Procedural complications did not differ between the stent-assisted coiling group (6%) and the balloon-assisted coiling group (9%, P = .5). The rates of complete aneurysm occlusion (Raymond score 1) at the most recent follow-up were significantly higher for the stent-assisted coiling group (75.4%) compared with the balloon-assisted coiling group (50%, P = .01). Progressive occlusion of incompletely coiled aneurysms was noted in 76.6% of aneurysms in the stent-assisted coiling group versus 42.8% in the balloon-assisted coiling group (P = .02). Retreatment rates were significantly lower with stent-assisted coiling (4.3%) versus balloon-assisted coiling (15.6%, P = .05). In multivariate analysis, stented aneurysms independently predicted both complete aneurysm obliteration and progression of occlusion. CONCLUSIONS: Stent-assisted coiling may yield lower rates of retreatment and higher rates of aneurysm obliteration and progression of occlusion at follow-up than balloon-assisted coiling with a similar morbidity rate.

Intracranial vertebral artery dissections: evolving perspectives.

Intracranial vertebral artery dissection (VAD) represents the underlying etiology in a significant percentage of posterior circulation ischemic strokes and subarachnoid hemorrhages. These lesions are particularly challenging in their diagnosis, management, and in the prediction of long-term outcome. Advances in the understanding of underlying processes leading to dissection, as well as the evolution of modern imaging techniques are discussed. The data pertaining to medical management of intracranial VADs, with emphasis on anticoagulants and antiplatelet agents, is reviewed. Surgical intervention is discussed, including, the selection of operative candidates, open and endovascular procedures, and potential complications. The evolution of endovascular technology and techniques is highlighted.