Biomedical subjects

Ian G Fleetwood

Publications and source records attributed to Ian G Fleetwood.

4 recordsLinked to original sources

PubMed2005

Anterograde ventricular irrigation during fourth ventricle region surgery.

OBJECTIVE: To reduce postoperative hydrocephalus following surgery in the region of the fourth ventricle. METHOD/TECHNIQUE: We describe the use of a conventionally placed lateral ventricular catheter to facilitate anterograde ventricular irrigation during surgery in the region of the fourth ventricle. This technique offers a safe alternative to more conventional approaches to fourth ventricular irrigation and obviates the need for placement of a third or fourth ventricular catheter and/or serial lumbar punctures by thoroughly flushing blood and tissue debris from the operative field at the time of surgery. RESULTS: Preliminary results spanning a five-year period show a lower incidence in the need for early ventriculo-peritoneal shunts (5%) and delayed ventriculo-peritoneal shunts (10%). CONCLUSION: This technique represents a safe method of reducing hydrocephalus following operative procedures in the region of the fourth ventricle.

Adult↗

PubMed2003

Deep arteriovenous malformations of the basal ganglia and thalamus: natural history.

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.

Adult↗

PubMed2003

Functional motor neurons differentiating from mouse multipotent spinal cord precursor cells in culture and after transplantation into transected sciatic nerve.

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 alpha1 1.2 (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.

Animals↗

PubMed2002

Arteriovenous malformations.

Arteriovenous malformations of the brain are congenital vascular lesions that affect 0.01-0.50% of the population, and are generally present in patients aged 20-40 years. The usual clinical presentations are haemorrhage, seizures, progressive neurological deficit, or headache. Results of natural history studies have shown a yearly haemorrhage rate of 1-4%. Frequency of rebleeding has increased over the years, and several factors that increase risk of haemorrhage have been identified. Although substantial, the morbidity associated with haemorrhages could be less than previously thought. Over the past decade, great advances have been made in application of endovascular embolisation techniques, stereotactic radiosurgery, and microsurgery, allowing effective multidisciplinary treatment of arteriovenous malformations, including those previously deemed to be untreatable. Increasing attention has been paid to management of flow-related aneurysms associated with these malformations. Finally, many reports of recurrent arteriovenous malformations have coincided with new theories regarding the embryogenesis of these disorders and laboratory work suggesting their proliferative potential.

Adult↗