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  • Author or Editor: Stephen C. MacDonald x
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Stephen P. Lownie, Alan H. Menkis, Rosemary A. Craen, Bernard Mezon, James MacDonald and David A. Steinman

✓ Giant partially thrombosed intracranial aneurysms are a challenge to treat surgically, and they are also unsuitable for coil embolization. The current options for treatment include extracranial—intracranial bypass followed by parent artery occlusion or direct surgical occlusion in which deep hypothermic circulatory arrest is used.

The authors report the use of another approach in the treatment of a giant anterior circulation aneurysm: selective brain cooling accomplished by extracorporeal perfusion. This facilitated direct surgery on a 4.2-cm, partially thrombosed aneurysm of the middle cerebral artery (MCA). A brain temperature of 22°C was achieved after 20 minutes of perfusion with blood cooled using an extracorporeal technique of femoral—common carotid artery perfusion. This was followed by a 20-minute period of surgical trapping of the MCA, then evacuation and clip occlusion of the aneurysm. During the period of selective brain cooling the patient's core body temperature was maintained above 35°C.

This technique of selective brain cooling may be a useful alternative to currently available surgical and endovascular methods of treatment for giant aneurysms.

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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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Oral Presentations

2010 AANS Annual Meeting Philadelphia, Pennsylvania May 1–5, 2010