Search PubMed⌕ Search

Biomedical subjects

P C Gates

Publications and source records attributed to P C Gates.

At least 19 recordsLinked to original sources
PubMed2006

Symptomatic and asymptomatic carotid stenosis: just when we thought we had all the answers.

The management of symptomatic and asymptomatic carotid stenosis has been a hotly debated topic for decades. The publication of four randomized controlled trials of carotid endarterectomy has clarified many of the issues. Patients with symptomatic carotid stenosis >70% benefit most with an absolute risk reduction of 17% over 2 years with numbers needed to treat of 3-6, whereas in patients with asymptomatic carotid stenosis >60%, the absolute risk reduction is 1% per annum (numbers needed to treat = 14-17). There is doubt about the benefit in women >70 years of age with asymptomatic stenosis. Carotid angioplasty and stenting is in its infancy and may one day supplant carotid endarterectomy as the treatment of choice; however, currently indications for this procedure include participation in randomized controlled trials, surgically inaccessible stenosis, in patients with combined symptomatic carotid and symptomatic coronary artery disease or in patients with severe co-morbidities that preclude formal carotid endarterectomy.

Aged↗
PubMed1998

Friedreich's ataxia presenting as adult-onset spastic paraparesis.

We have studied a man with an atypical form of Friedreich's ataxia (FRDA), who presented at age 26 years with a 2-year history of unsteadiness and clumsiness. The predominant feature of his initial neurological examination was a spastic paraparesis, along with a mild distal weakness and hyperreflexia of the upper limbs. He also displayed limb ataxia. Frataxin GAA repeat sizes were 1,040/690. This unusual FRDA presentation is not dissimilar to that of Acadian spastic ataxia.

Adult↗
PubMed1996

Streptokinase for acute ischemic stroke with relationship to time of administration: Australian Streptokinase (ASK) Trial Study Group.

OBJECTIVES: To determine whether the administration of 1.5 million units of streptokinase intravenously within 4 hours of the onset of acute ischemic stroke would reduce morbidity and mortality at 3 months and whether outcomes may be better for those receiving therapy within 3 hours of stroke onset compared with those receiving it after 3 hours. DESIGN: Randomized, double-blind, placebo-controlled trial with 3-month follow-up. PARTICIPANTS: A total of 340 patients, aged 18 to 85 years, with moderate to severe strokes were randomized from 40 centers throughout Australia from June 1992 to November 1994. INTERVENTION: Administration of 1.5 million units of streptokinase or placebo intravenously in 100 mL of normal saline over 1 hour. MAIN OUTCOME MEASURE: Combined death and disability score (Barthel index <60) 3 months after the stroke. RESULTS: Using an intention-to-treat analysis with a combined death and disability score at 3 months after stroke as the primary end point, we found a nonsignificant overall trend toward unfavorable outcomes for streptokinase vs placebo (relative risk [RR] of unfavorable outcome, 1.08; 95% confidence interval [CI], 0.74-1.58) and an excess of hematomas (13.2%[12.6% symptomatic] in the treated group, 3% [2.4% symptomatic] for placebo [P<.01]). However, poor outcomes were confined to patients receiving therapy more than 3 hours after stroke onset (RR of unfavorable outcome, 1.22; 95% CI, 0.80-1.86). In contrast, among the 70 patients who were entered into the trial within 3 hours of stroke onset, there was a trend toward improved outcomes for those who received streptokinase (RR of unfavorable outcome, 0.66; 95% CI, 0.28-1.58), and this outcome pattern was significantly better than for those receiving therapy after 3 hours (P=.04). Streptokinase administration resulted in excess deaths in the group treated after 3 hours (RR, 1.98; 95% CI, 1.18-3.35), but not among those treated within 3 hours (RR, 1.11; 95% CI, 0.38-3.21). CONCLUSION: The administration of streptokinase within 4 hours of acute ischemic stroke increased morbidity and mortality at 3 months. While treatment within 3 hours of stroke was safer and associated with significantly better outcomes than later treatment, it showed no significant benefit over placebo. The timing of thrombolytic therapy for acute stroke is critical.

Acute Disease↗
PubMed1994

Renal biopsy in angiotropic large cell lymphoma.

Angiotropic large cell lymphoma is a rare microvascular malignancy presenting most commonly with neurologic symptoms but, from a review of the scarce literature, also invariably with evidence of renal involvement. We believe this to be the first case in which the diagnosis was made by initial renal biopsy and in which follow-up of the effectiveness of chemotherapy was assessed by a second biopsy. Proteinuria is prominent in this condition and may result either from the epithelial cell abnormalities associated with the minimal-change lesion or from a direct interaction between the B cell-derived malignant cells and the glomerular endothelium. We believe the kidney may be the most appropriate organ with which to histologically confirm the diagnosis of suspected angiotropic large cell lymphoma and examination of the kidney may prove to be the best way to allow histologic follow-up of the disease or the efficacy of its therapy.

Biopsy, Needle↗
PubMed1993

Carotid stenosis and perioperative stroke risk in symptomatic and asymptomatic patients undergoing vascular or coronary surgery.

BACKGROUND AND PURPOSE: The management of asymptomatic carotid stenosis found before vascular or coronary surgery is unclear from the literature. We aimed to define the relation of carotid stenosis to perioperative stroke in all patients, symptomatic and asymptomatic, and so determine a policy for the management of asymptomatic carotid stenosis in patients requiring major surgery. METHODS: We conducted a prospective clinical and Duplex ultrasound study of 358 consecutive noncarotid major vascular or coronary artery bypass operations, with a moratorium on endarterectomy for asymptomatic carotid stenosis. RESULTS: There were 145 vascular and 213 coronary bypass operations. Ten of the 49 cases with prior symptoms of cerebral ischemia (38 carotid, 11 vertebrobasilar) had symptomatic stenosis of 50% or greater or occlusion, and 3 of these (30%) had ipsilateral perioperative cerebral infarction (95% confidence interval, 6.67% to 65.25%). Two of these occurred ipsilateral to symptomatic carotid occlusions, and 1 occurred ipsilateral to an 80% symptomatic stenosis. One symptomatic patient with bilateral 30% stenosis had a perioperative infarct in the asymptomatic hemisphere. Among the 309 asymptomatic patients, 1 perioperative infarct occurred ipsilateral to carotid stenosis of 30%. In all there were 5 (1.4%) perioperative (within 72 hours) and 2 late (after 18 days) strokes. All strokes were hemisphere infarcts confirmed by computed tomography. There were 53 cases with 50% or greater asymptomatic carotid stenosis or occlusion, including 28 with 80% or greater stenosis or occlusion. None had an ipsilateral perioperative stroke (95% confidence interval, 0% to 6.72%). CONCLUSIONS: We conclude that the risk of perioperative stroke related to symptomatic carotid stenosis may be high, but for asymptomatic carotid stenosis the risk is low and does not justify preoperative prophylactic carotid endarterectomy.

Aged↗
PubMed1993

Orthostatic tremor (shaky legs syndrome).

Nine patients (mean age 73 years: range 62-83 years) are described with a characteristic tremor or instability of the trunk and lower limbs which occurred when standing still, and which was either diminished or abolished by walking. Three had essential tremor of the upper limbs. The duration of the disorder ranged between 4 months and 20 years (mean 5 years). In all cases the condition worsened with time. Eight patients responded to clonazepam (0.5 to 2.0 mg per day) and one to chlordiazepoxide (30 mg per day). Orthostatic tremor is a disabling condition that responds to benzodiazepine treatment and may be more frequent than previously recognised.

Aged↗
PubMed1993

Watershed cerebral infarction associated with perioperative hypotension.

The pathogenesis of perioperative stroke is not clear from the literature. To explore the influence of various risk factors we examined the clinical, Duplex ultrasound and computerised tomography findings of all cases suffering cerebral infarction within 24 hours of surgery in a prospective series of 358 coronary or peripheral vascular reconstructive operations. Four patients (1.1%) had cerebral infarcts within 24 hours of surgery, all associated with perioperative systolic blood pressures of less than 90 mmHg. The other significant risk factor was previous cerebral ischaemic symptoms. Haemodynamic cerebral ischaemia occurred immediately after operation in 2 of 10 cases with severe symptomatic carotid stenosis or occlusion (stroke risk 20%; 95% confidence interval 2.52%-55.61%). Two cases with mild carotid disease had cerebral infarcts in previously asymptomatic hemispheres following coronary artery bypass graft surgery. One of these had clinical and computerised tomographic evidence of cortical watershed infarction. We conclude that cerebral haemodynamics are important in perioperative stroke and that symptomatic patients with severe carotid disease may be at high risk of perioperative watershed infarction.

Blood Pressure↗
PubMed1989

Carotid endarterectomy: why question it now?

Carotid endarterectomy has been accepted widely as an important stroke-prevention tool since the 1950s, in spite of the lack of any proof of its efficacy in randomized, controlled clinical trials in either symptomatic or asymptomatic patients. While surgery for asymptomatic carotid disease always has been controversial, the indications and benefits of carotid endarterectomy in symptomatic patients now are being questioned also, although the available evidence suggests that the operation, when performed in expert hands, reduces the incidence of subsequent strokes in patients with minor, carotid-territorial ischaemic events and significant ipsilateral carotid disease. (A morbidity and mortality rate of more than 3% is unacceptable, and hence the procedure should be undertaken only by those who are skilled in its performance). For each patient, a decision has to be made as to whether the potential reduction of the risk of stroke outweighs the immediate surgical risk of stroke or death. Some large, expensive and important randomized clinical trials are either proposed or under way in North America and Europe to evaluate the precise role of carotid endarterectomy in the prevention of strokes. The basis for the current questioning of carotid endarterectomy and the rationale for these trials are addressed in this review.

Carotid Arteries↗
PubMed1988

Asymptomatic cerebral infarction in patients with chronic atrial fibrillation.

A retrospective analysis of 54 patients with atrial fibrillation presenting with symptoms of cerebral ischemia between 1980 and 1985 was performed. Seven patients (13%) had computed tomographic evidence of previous, clinically silent cerebral infarction. In a control group of 168 persons (studied prospectively) in sinus rhythm presenting with symptoms of cerebral ischemia, seven (4%) had computed tomographic evidence of previous, clinically silent cerebral infarction (p less than 0.05). In those patients with atrial fibrillation all infarcts were peripheral and consistent with embolism, while in three of the seven patients in sinus rhythm the asymptomatic infarcts were lacunes.

Atrial Fibrillation↗
PubMed1986

Cerebral venous thrombosis. A retrospective review.

In a retrospective survey of 66 cases (46 proven) of cerebral venous thrombosis in a large number of public teaching hospitals in Australia, the quantity of cases in institutions of similar size varied widely. There were 29 fatal cases (all underwent an autopsy) and in 20 of these the venous thrombosis was considered to be the major cause of death. In 15 of the deaths due to cerebral venous thrombosis the diagnosis was not suspected before death. In 27 cases (18 proven) the underlying cause was infection, while only two cases (both confirmed) were associated with oral contraceptives. These findings suggest that although rare, cerebral venous thrombosis is underdiagnosed and that, even in the era of modern antibiotics, sepsis is the commonest single identifiable cause.

Adult↗
PubMed1986

Bilateral occlusion of vertebral artery: clinical patterns and long-term prognosis.

We studied 17 patients with atherosclerotic bilateral occlusion of vertebral arteries (VA) identified by angiography. Seven had vertebrobasilar TIAs, eight a brainstem stroke (severe in two), and two had only carotid symptoms. Brainstem strokes were more frequent with bilateral intracranial occlusion (60%) than with at least one extracranial occlusion (28.6%), but long-term prognosis did not differ in these two groups. In follow-up, the mortality rate was 4.5% per year, and the stroke rate was 1.8% per year. Major functional disability was seen in 16.7% of the survivors. Bilateral distal VA occlusion may sometimes have a better prognosis than previously assumed. These findings raise doubts about the value of extra-intracranial surgical bypass procedures in patients with these lesions.

Adult↗
PubMed1986

CT metrizamide myelography in syringomyelia: sensitivity and specificity.

In a retrospective study of 32 patients with "proven" syringomyelia and 15 patients with an alternate proven diagnosis, a change in the caliber of the spinal cord with different positions ("collapsing cord sign or cord collapse") had a sensitivity of 38% and a specificity of 87%. Central cord enhancement ("bull's-eye") on delayed CT had a sensitivity and specificity of 91% and 87%, respectively. The positive predictive value of cord collapse was 87%, while the positive predictive value of central cord enhancement was 94%.

Humans↗
PubMed1986

Extradural malignancy simulating brachial neuritis.

A 57 year old man is described who presented with symptoms and signs suggestive of brachial neuritis. Sparing of the serratus anterior both clinically and on electromyography suggested that the lesion was in the brachial plexus, thus supporting the diagnosis. Subsequent investigation showed an extradural tumour at C5-C6 level. Sparing of serratus anterior does not definitively localize the pathology as distal to the nerve roots.

Adenocarcinoma↗