Carotid endarterectomy: recommendations for management of transient ischaemic attack and ischaemic stroke. Association of British Neurologists.
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Cerebrovascular Disorders↗
Biomedical subjects
M M Brown
Publications and source records attributed to M M Brown.
Cyclosporin A therapy in paraprotein-associated neuropathy.
A case of IgG paraprotein-associated demyelinating neuropathy complicated by respiratory failure, which was unresponsive to standard immunosuppressive drug therapy, is reported. Cyclosporin A therapy resulted in a marked clinical recovery with objective improvement in nerve conduction and vital capacity. The beneficial response suggests that cell-mediated immunity is an important pathogenetic mechanism, and that cyclosporin A may be useful in the treatment of other refractory cases of paraprotein-associated neuropathy.
Adult↗
Factors affecting the toxicity of dioxin-like toxicants: a molecular approach to risk assessment of dioxins.
The numerous toxic responses of dioxin-like compounds are mediated by the intracellular Ah (aryl hydrocarbon) receptor. It has been suggested that the regulation of dioxins and similar substances could be placed on a molecular foundation by considering the proportion of Ah-receptor sites occupied by toxicant molecules. The present work has shown that the following formation not yet available would be needed in order to develop this approach: correlation between dioxin exposure and human tissue levels; accurate determination of the association constants for human Ah-receptor with toxicant, and for human receptor-ligand complex with DNA; and knowledge of the intracellular concentrations of both receptor binding sites and DNA binding sites. Furthermore, since not all dioxin-like substances behave identically, this information would need to be gathered for a wide variety of substances.
Animals↗
Silhouettes elicit alarm calls from captive vervet monkeys (Cercopithecus aethiops).
In Part 1, we analyzed alarm calls produced by captive vervets (Cercopithecus aethiops) in response to naturally occurring stimuli. Females and juveniles regularly alarm called to airplanes, birds, and barking dogs. Juvenile females accounted for 60% of these alarm calls. In Part 2, we isolated several monkeys from the colony and presented them with life-sized silhouettes of a leopard, snake, eagle, baboon, vervet, and goose. Adult monkeys alarm called more than did juveniles. Alarm calls were elicited by leopard, snake, baboon, and vervet silhouettes, but none were elicited by eagle or goose silhouettes. Some leopard and snake alarm calls matched those recorded in the wild in the context of the vervets' natural predators. Results indicate that silhouette stimuli are a useful technique for eliciting monkey vocalizations in the laboratory.
Animals↗
Balloon angioplasty for cerebrovascular disease.
Percutaneous transluminal angioplasty (PTA) has become an established treatment for peripheral, renal and coronary vascular disease, where the success rate approaches 90% with complications occurring in less than 5% of patients. There has been a reluctance to recommend PTA of the internal carotid artery (ICA) because of concern about the risks of cerebral embolism. However, there are now a number of reports of technically successful PTA for ICA stenosis, as well as stenosis of other brachiocephalic arteries, demonstrating an improvement in vessel diameter and contour. Complications to date include transient neurological symptoms, asymptomatic carotid dissection and arterial spasm, but the risk of permanent stroke seems to be relatively low. The risks of embolization may be reduced by anticoagulation and avoiding arteries with obvious thrombus or ulceration. Current technical difficulties are likely to be surmounted by improvements in catheter design. PTA is most suitable for smooth ICA stenosis causing haemodynamic symptoms, fibromuscular dysplasia, surgically inaccessible stenosis, and patients with medical risk factors increasing the risks of carotid endarterectomy, such as ischaemic heart disease. Only brief admission is required, avoiding the surgical and anaesthetic risks of carotid endarterectomy. The preliminary results are encouraging enough to set up a randomized trial to determine the risks and benefits. It remains to be seen whether alterations in the calibre or contour of the vessel wall will reduce subsequent stroke. Whether cerebrovascular PTA will enter general use will depend on the balance of the risk-benefit equation.
Angioplasty, Balloon↗
Age- and sex-related changes in Tyr-MIF-1-like immunoreactivity in rat plasma.
The concentrations in plasma of the biologically active endogenous peptide Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) have not been measured during development or in female rats. By radioimmunoassay, we found that Tyr-MIF-1-like immunoreactivity (Tyr-MIF-1-LI) was first consistently detectable in plasma when the rat was 5 days old, and then gradually increased to adult concentrations by day 15. In male rats, the levels remained relatively constant for the next 21 months. In female rats, plasma concentrations of Tyr-MIF-1-LI at day 15 were about the same as in male rats. At 6 months of age, however, the concentrations in females decreased by half and by 21 months of life were only about a third of the concentrations found at day 15 or in age-matched males. The differences with age were not due to the length of time of storage of the samples, because another group of rats 1 month old was killed on the same day as 5-day-old rats and still showed several times more Tyr-MIF-1-LI in the plasma; again, no differences were found between male and female rats at either 5 days or 1 month. A single injection of estradiol followed by progesterone lowered the concentrations in 1-month-old male rats. In female rats that were either ovariectomized or sham-ovariectomized, the expected similarity in their plasma concentrations of Tyr-MIF-1-LI was found at 1 month of age.(ABSTRACT TRUNCATED AT 250 WORDS)
Age Distribution↗
Digital subtraction angiography (DSA) of the extracranial cerebral vessels: a direct comparison between intravenous and intra-arterial DSA.
Fifty patients being investigated for ischaemic cerebrovascular disease underwent both intravenous digital subtraction angiography (IV-DSA) and intra-arterial arch digital subtraction angiography (arch-DSA) to enable a direct comparison to be made between the two techniques. The overall quality of the images obtained by arch-DSA was better than that obtained by IV-DSA, but there was no significant difference between the number and gradation of stenoses detected by the two techniques. No significant stenosis was missed by IV-DSA and the technique was found to be sufficiently accurate for it to be used as a screening procedure for carotid bifurcation stenoses suitable for carotid endarterectomy. The advantages and limitations of both techniques are discussed.
Adult↗
Another complication of arterial cannulation.
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Aged↗
Small deep cerebral infarcts associated with occlusive internal carotid artery disease. A hemodynamic phenomenon?
Small deep cerebral infarcts, often referred to as lacunes, have been traditionally associated with small-vessel disease affecting the deep penetrating arterial system. We describe 10 cases where these infarcts were associated with severe, ipsilateral internal carotid artery occlusive disease. Seven of these patients also had severe occlusive disease of the contralateral internal carotid artery. The clinical and radiologic features, in combination with studies of cerebral blood flow, were consistent with hemodynamically mediated cerebral ischemia. Occlusive internal carotid artery disease may be more commonly associated with hemodynamic cerebral ischemia than previously believed, and small cerebral infarcts in the deep arterial border zone areas are likely to be an important manifestation of this process.
Adult↗
Prevention of neural allograft rejection in the mouse following in vivo depletion of L3T4+ but not LYT-2+ T-lymphocytes.
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Animals↗
Feasibility of percutaneous transluminal angioplasty for carotid artery stenosis.
Percutaneous transluminal balloon angioplasty was attempted in seven patients with internal carotid artery stenosis, including one patient who had two procedures. All had recurrent, carotid territory, neurological symptoms considered haemodynamic in origin. Six had occlusion of the contralateral internal carotid artery. Cerebral blood flow studies confirmed diminished cerebrovascular reserve in six patients studied. In five patients (six procedures) angioplasty of the stenosed internal carotid artery was carried out successfully. With two patients technical difficulty in crossing the stenosis prevented angioplasty and in one patient with bilateral stenosis the procedure was not attempted on the second side because of the severity of the stenosis. In two patients transient aphasia developed during cannulation of the carotid artery and in another a transient monoparesis developed during the procedure. Both these haemodynamic complications recovered within ten minutes. No other complications occurred. Our experience suggests that balloon angioplasty is technically feasible in the management of stenotic carotid disease associated with haemodynamic stroke. It is a technically simple procedure requiring only a brief admission to hospital. However, its general application to patients with thromboembolic carotid-territory stroke will depend on the risk/benefit ratio compared to carotid endarterectomy or to conventional medical treatment.
Angiography, Digital Subtraction↗
Central retinal vein obstruction and axial length.
The axial lengths of 24 consecutive adult eyes with unilateral central retinal vein obstruction (CRVO) were compared with those of contralateral unaffected eyes and those of a control population. The lengths of the two eyes of persons with a unilateral CRVO were not significantly different. By contrast, eyes of persons with CRVO averaged 0.67 mm (approximately 2 diopters) shorter than their control counterparts (P = .03). This anatomic difference may be a factor in the development of CRVO.
Adult↗
Extracorporeal membrane oxygenation in adults: a nursing challenge.
ECMO is an aggressive treatment for selected patients who are unresponsive to conventional therapy for respiratory failure. Although its use in neonates is well documented, the number of successful reports in adults is limited. Venovenous ECMO represents a therapeutic option for adult patients with severe respiratory failure that has not responded to diuresis, high oxygen flows, and positive end-expiratory pressure. As medical centers obtain more experience with and resources for adult ECMO, critical care nurses will need to develop more familiarity with this technology.
Aged↗
Effect of oxpentifylline on blood viscosity and cerebral blood flow in man.
The effects of intravenous oxpentifylline on blood viscosity and cerebral blood flow were studied in eight patients with cerebrovascular disease using a double-blind placebo controlled design. A single dose of 200 mg oxpentifylline in 10 ml saline was given by intravenous injection over 10 min and compared with 10 ml saline alone. Whole blood and plasma viscosity were measured in a Contraves LS 30 coaxial viscometer at shear rates of 0.7 and 94.5 s-1. Cerebral blood flow was measured by the non-invasive intravenous xenon133 clearance method. The measurements were made before and then 30 min after the start of the injection of drug or saline alone. Oxpentifylline was found to have no significant effect on blood viscosity or cerebral blood flow.
Adult↗
Sarcoidosis presenting with stroke.
A 25-year-old black man with sarcoidosis presented with transient ischemic attacks followed by sudden, persistent right hemiparesis. He gave a history of recent, recurrent lower motor neuron facial palsy. Computed tomography demonstrated an infarct in the left internal capsule. Chest x-ray film showed bilateral hilar and mediastinal lymphadenopathy and multiple opacities in the lung fields. Serum angiotensin converting enzyme concentration was raised, and a Kveim test was positive for sarcoidosis. Despite clear pathologic reports of cerebral vasculitis in neurosarcoidosis, the occurrence of stroke is extremely rare.
Adult↗
Retroviruses and diseases of the nervous system.
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Acquired Immunodeficiency Syndrome↗
Preoperative and postoperative levels of plasma protein and amino acid in esophageal and lung cancer patients.
The metabolic changes following thoracic surgery in three groups of patients (esophageal cancer, lung cancer, and hiatus hernia) have been studied. Before operation patients with esophageal cancer, but not those with lung cancer, had significantly lower plasma total protein and albumin than patients with hiatus hernia. After surgery plasma albumin and total protein fell in both esophageal cancer and hiatus hernia patients, a development attributed to poor nutrition and restricted calorie diet in these two groups of patients respectively. With the exception of alanine and arginine in lung cancer patients, and free tryptophan in lung and esophageal cancer patients, the preoperative concentrations of all plasma amino acids were similar in both groups of cancer patients and in those with hiatus hernia. After operation the concentrations of glutamine, total tryptophan, alanine, glycine, and arginine fell sharply, whereas those of phenylalanine, lysine, valine, and leucine were slightly or not at all affected by surgery. The immediate postoperative fall of plasma free amino acids is thought to be due to the increased rate of gluconeogenesis. The rise of free fraction of plasma tryptophan after surgery is related to the raised level of plasma free fatty acids and increased secretions of catecholamines, which is believed to follow surgery.
Aged↗
Autopsy validation of MRI in central pontine myelinolysis.
In a fatal case of central pontine myelinolysis (CPM) a low field strength (0.08 Tesla) magnetic resonance image revealed reduction of image intensity in the pons with sparing of two central symmetrical areas in the ventral portion. The latter correlated with preservation of centrally located groups of longitudinal myelinated nerve fibres shown at autopsy. Although such sparing is well recognised in pathological studies of CPM it has never previously been demonstrated in life.
Adult↗