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Biomedical subjects

T J Harrington

Publications and source records attributed to T J Harrington.

8 recordsLinked to original sources
PubMed2003

Papaverine angioplasty to treat cerebral vasospasm following traumatic subarachnoid haemorrhage.

The management of vasospasm associated with traumatic subarachnoid haemorrhage presents many challenges. We present a 20-year-old male admitted after sustaining a closed head injury complicated by a Fisher grade III traumatic subarachnoid haemorrhage. Despite treatment with intravenous nimodipine he developed a delayed ischaemic neurological deficit due to cerebral arterial vasospasm. The vasospasm was successfully managed with serial papaverine angioplasty.

Adult↗
PubMed2001

Combined endovascular and open surgery for four-vessel cerebrovascular occlusive disease.

PURPOSE: To report a case of bilateral simultaneous percutaneous transluminal angioplasty and stenting of the intracranial vertebral arteries prior to staged bilateral carotid endarterectomy. CASE REPORT: A 68-year-old man presented with a 3-month history of recurrent, intermittent left-sided weakness and diplopia. Imaging defined bilateral 80% to 99% internal carotid artery stenoses and >90% stenoses of both distal vertebral arteries at the level of the foramen magnum. Bilateral intracranial vertebral artery stenting was performed, followed by staged carotid endarterectomies. No complications occurred, and the patient recovered uneventfully from all 3 procedures. He remains symptom- and event-free 20 months later. CONCLUSIONS: Our initial success in this case indicates a role for percutaneous transluminal angioplasty and stenting as an alternative to open surgery for intracranial vertebral artery stenosis.

Aged↗
PubMed2001

Angioplasty and stenting in the posterior cerebral circulation.

PURPOSE: To report initial experience with intracranial vertebral artery (VA) and basilar artery (BA) percutaneous transluminal angioplasty (PTA) and stenting. METHODS: Eleven patients (10 men; mean age 66 years, range 56-75) with intracranial 14 VA and 3 BA stenoses were managed from December 1997 through November 1999. All patients presented with vertebrobasilar ischemia (VBI) despite antiplatelet and anticoagulant therapy. Clinical presentations included visual disturbance (n = 8), dysarthria/dysphasia (n = 5), and vertigo (n = 5). RESULTS: Five patients underwent PTA only of 7 lesions with a mean preprocedural stenosis of 80% (range 50%-90%) that was reduced to 54% (range 30%-70%) after dilation. Six patients received 9 stents, 2 for VA dissections, 3 for tandem lesions, and 1 for a BA lesion. There were no embolic strokes. Patients were followed by clinical evaluation and personal or telephone interviews. Over a mean 18-month follow-up (range 12-35), 8 (73%) patients remained asymptomatic, while 3 (27%) had permanent deficits, 2 related to the procedure and 1 owing to distal disease CONCLUSIONS: Intracranial VA or BA angioplasty and stenting alleviated symptoms in patients with vertebrobasilar ischemia despite best medical management and may prevent stroke.

Aged↗
PubMed1996

Construction of an ultrasound biopsy phantom.

The technique for construction of an agar-based ultrasound biopsy phantom is described. Features include tissue equivalent reflectivity, long life and non-shadowing targets. The phantom is useful for learning the necessary co-ordination between needle and probe for ultrasound needle guidance. This skill should initially be practised in vitro, on a device such as this.

Biopsy, Needle↗
PubMed1992

Ceramic membrane microfilter as an immobilized enzyme reactor.

This study investigated the use of a ceramic microfilter as an immobilized enzyme reactor. In this type of reactor, the substrate solution permeates the ceramic membrane and reacts with an enzyme that has been immobilized within its porous interior. The objective of this study was to examine the effect of permeation rate on the observed kinetic parameters for the immobilized enzyme in order to assess possible mass transfer influences or shear effects. Kinetic parameters were found to be independent of flow rate for immobilized penicillinase and lactate dehydrogenase. Therefore, neither mass transfer nor shear effects were observed for enzymes immobilized within the ceramic membrane. Both the residence time and the conversion in the microfilter reactor could be controlled simply by regulating the transmembrane pressure drop. This study suggests that a ceramic microfilter reactor can be a desirable alternative to a packed bed of porous particles, especially when an immobilized enzyme has high activity and a low Michaelis constant.

Biotechnology↗
PubMed1991

Effects of fluid shear on immobilized enzyme kinetics.

There have been a number of reports concerning the damaging effects of shear on globular proteins in solution. Some recent work has indicated, however, that globular proteins in solution are relatively stable, but may be inactivated at air-liquid interfaces during shearing. This study investigated the effects of fluid shear on immobilized enzyme activity. Immobilized enzyme reactors were built to operate with the enzyme immobilized at the boundary of a fluid flow field. Two different enzymes, penicillinase and lactate dehydrogenase, were covalently bound to the interior surface of nylon tubes. Fluid shear rate was changed by varying the flow rate of substrate (reactant) solution through the tube, and fluid shear stresses were increased by increasing the viscosity of the recirculating solution. There were no observed effects of fluid shear on immobilized penicillinase or lactate dehydrogenase activity at shear rates of up to 10,350 s-1 or at shear stresses of up to 73 Pa.

Animals↗
PubMed1988

What a CEO applicant needs to know.

The CEO applicant needs to assess--and the hospital needs to provide--as much information as possible in the limited time available for interviewing. The hospital planner plays a critical role in gathering this information and in helping the board to answer questions about ownership, governance, quality of care, financial expectations and the hospital's future.

Governing Board↗