Stephen P. M. J. Downey

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It is widely held that the frontal cortex plays a critical part in certain aspects of spatial and non-spatial working memory. One unresolved issue is whether there are functionally distinct subdivisions of the lateral frontal cortex that subserve different aspects of working memory. The present study used positron emission tomography (PET) to demonstrate(More)
Antemortem demonstration of ischemia has proved elusive in head injury because regional CBF reductions may represent hypoperfusion appropriately coupled to hypometabolism. Fifteen patients underwent positron emission tomography within 24 hours of head injury to map cerebral blood flow (CBF), cerebral oxygen metabolism (CMRO2), and oxygen extraction fraction(More)
OBJECTIVE To investigate the effect of hyperventilation on cerebral blood flow in traumatic brain injury. DESIGN A prospective interventional study. SETTING A specialist neurocritical care unit. PATIENTS Fourteen healthy volunteers and 33 patients within 7 days of closed head injury. INTERVENTIONS All subjects underwent positron emission tomography(More)
Rebleeding following aneurysmal subarachnoid haemorrhage is a major factor contributing to unfavourable outcome. Antifibrinolytic agents reduce the rate of rebleeding but increase the risk of cerebral ischaemia and infarction and hence provide no overall benefit. To address the theoretical concern that recombinant activated factor VII (NovoSeven, Novo(More)
There is increasing recognition that magnetic resonance (MR) imaging and spectroscopy may provide important information in the assessment of patients with acute brain injury. However, optimum care of the acutely head injured patient requires monitoring of intracranial pressure (ICP). Although many monitoring modalities have been integrated into commercially(More)
We have synthesized two potential positron emission tomography (PET) radioligands for the endothelin (ET) receptor. [11C]-PD156707 was produced by O-methylation of PD169390 using [11C]iodomethane. Radiochemical conversions of the order of 74 +/- 3.2% (n = 8) were obtained. The radiochemical purity of the isolated [11C]-PD156707 was 99% and the specific(More)
Chemical fractions from 4 shale oils including one produced in an above-ground retort (Paraho), 2 produced below ground by in situ method (Occidental and Geokinetics), and 1 produced by a simulated modified in situ process (Livermore), were tested for mutagenicity against Salmonella typhimurium TA98 in the Ames assay system. Their mutagenic activities were(More)
Supported, in part, by the Medical Research Council, a Technology Foresight Award from the UK Government, and by a Royal College of Anaesthetists/British Journal of Anesthesia project grant. Dr. Coles was funded by a Research Training Fellowship from the Addenbrooke’s Charities and is currently a Wellcome Research Training Fellow. Dr. Minhas was supported(More)
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