Enriched motor neuron populations derived from bacterial artificial chromosome-transgenic human embryonic stem cells.

S OF OPEN PAPERS controls. Injection of Ad-GAD65 into the trigeminal ganglion also resulted in long-term analgesia following a chronic constriction injury of the infraorbital nerve, a model of orofacial neuropathic pain. Immunohistochemical analysis showed that adenovirus-mediated GAD65 was expressed mainly in the satellite glial cells that surround the perikarya of sensory neurons in the trigeminal ganglion, suggesting that the analgesic effects were mediated by an intraganglionic, paracrine release of GABA. CONCLUSION: Adenoviral vector-mediated expression of GAD65 is a suitable means to synthesize GABA in sensory ganglia and produce analgesia in different pain models. 884 Negative Exploration during Microvascular Decompression: Initial Experience with Intraoperative Glycerol Rhizotomy for Trigeminal Neuralgia Richard S. Zimmerman, M.D., Amy Theiler, PA-C, Naresh P. Patel, M.D. INTRODUCTION: Microvascular decompression (MVD) has been shown to be effective for trigeminal neuralgia (TN). Although patient selection criteria and outcome have been described in detail, there are few reports in the literature focusing on options when the exploration is negative for vascular compression of the trigeminal nerve. One option involves partial sectioning of the root with complications such as facial numbness and incomplete or no pain relief. We describe an alternative, namely open glycerol rhizotomy (OGR), carried out intraoperatively when no discreet vascular compression is observed. METHODS: A total of 101 consecutive MVD cases for TN were reviewed, 14 of which had no vascular compression identified by an experienced surgeon. Included in these 14 were patients who failed previous procedures (e.g., MVD, gamma knife). For the 14 negative explorations, a droplet of glycerol was placed 3 to 4 mm distal to the root entry zone of the sensory portion of the trigeminal root. These cases were retrospectively reviewed for follow-up and to evaluate outcomes. RESULTS: The procedure was tolerated well by all patients. Thirteen of the 14 experienced immediate complete facial pain relief; seven of the 14 experienced initial facial numbness described as mild, but all patients retained their ipsilateral corneal reflex. Reassessment at 6 weeks revealed that nine of 14 had no pain, two were improved, and three had the same pain as prior to surgery. Between 6 months and 2 years after surgery, two patients restarted medication and two had a percutaneous glycerol rhizotomy. There were no cases of anesthesia dolorosa. There were no other neurological deficits and no deaths. CONCLUSION: Intraoperative glycerol rhizotomy appears to be effective when no significant vascular compression is observed and is associated with outcomes comparable to other rhizotomy techniques. Additional follow-up is necessary to establish long-term results, but the initial results suggest the potential for an alternative method of rhizotomy. Transgenic method for combinatorial expression of fluorescent proteins. Hippocampal granule neuron (blue) in mouse dentate gyrus. From, Livet J, Weissman TA, Kang H, Draft RW, Lu J, Bennis RA, Sanes JR, Lichtman JW: Transgenic strategies for combinatorial expression of fluorescent proteins in the nervous system. Nature 450:56–62, 2007. See Elder, pp 1358–1359.