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  • Author or Editor: Ian G. Fleetwood x
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Stephen C. MacDonald, Ian G. Fleetwood, Shawn Hochman, Janice G. Dodd, Gavin K. W. Cheng, Larry M. Jordan and Robert M. Brownstone

Object. One of the current challenges in neurobiology is to ensure that neural precursor cells differentiate into specific neuron types, so that they can be used for transplantation purposes in patients with neuron loss. The goal of this study was to determine if spinal cord precursor cells could differentiate into motor neurons both in culture and following transplantation into a transected sciatic nerve.

Methods. In cultures with trophic factors, neurons differentiate from embryonic precursor cells and express motor neuronal markers such as choline acetyltransferase (ChAT), Islet-1, and REG2. Reverse transcription—polymerase chain reaction analysis has also demonstrated the expression of Islet-1 in differentiated cultures. A coculture preparation of neurospheres and skeletal myocytes was used to show the formation of neuromuscular connections between precursor cell—derived neurons and myocytes both immunohistochemically and electrophysiologically. Following various survival intervals, precursor cells transplanted distal to a transection of the sciatic nerve differentiated into neurons expressing the motor neuron markers ChAT and the α11.2 (class C, L-type) voltage-sensitive Ca++ channel subunit. These cells extended axons into the muscle, where they formed cholinergic terminals.

Conclusions. These results demonstrate that motor neurons can differentiate from spinal cord neural precursor cells grown in culture as well as following transplantation into a transected peripheral nerve.

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Familial trigeminal neuralgia

Case report and review of the literature

Ian G. Fleetwood, A. Micheil Innes, Susan R. Hansen and Gary K. Steinberg

✓ The authors report the case of a 45-year-old woman with medically intractable trigeminal neuralgia (TN) in whom a good clinical response to partial sectioning of the trigeminal nerve was attained. No evidence of vascular compression was found intraoperatively. Several other members of her family, involving three generations, also suffered from TN. The treatment of all affected patients is discussed in the context of a literature review in which the controversies surrounding the origins of the disease and treatment options for patients with the familial variant of TN are addressed.

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Ian G. Fleetwood, Mary L. Marcellus, Richard P. Levy, Michael P. Marks and Gary K. Steinberg

Object. Patients with arteriovenous malformations (AVMs) in a deep location and with deep venous drainage are thought to be at higher risk for hemorrhage than those with AVMs in other locations. Despite this, the natural history of AVMs of the basal ganglia and thalamus has not been well studied.

Methods. The authors retrospectively evaluated a cohort of 96 patients with AVMs in the basal ganglia and thalamus with respect to the tendency of these lesions to hemorrhage between the time of detection and their eventual successful management.

The 96 patients studied had a mean age of 22.7 years at diagnosis, and 51% were male. Intracranial hemorrhage (ICH) was the event leading to clinical detection in 69 patients (71.9%), and 85.5% of these patients were left with hemiparesis. After diagnosis, 25 patients bled a total of 49 times. The cumulative clinical follow up after detection but before surgical management was 500.2 patient-years. The risk of hemorrhage after detection of an AVM of the basal ganglia or thalamus was 9.8% per patient-year.

Conclusions. The rate of ICH in patients with AVMs of the basal ganglia or thalamus (9.8%/year) is much higher than the rate in patients with AVMs in other locations (2–4%/year). The risk of incurring a neurological deficit with each hemorrhagic event is high. Treatment of these patients at specialized centers is recommended to prevent neurological injury from a spontaneous ICH.