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Biomedical subjects

R Fraser

Publications and source records attributed to R Fraser.

483 records · Page 27Linked to original sources
PubMedDate not supplied

Fatal late onset necrotising enterocolitis in a term infant: Atypical Kawasaki disease or polyarteritis nodosa of infancy?

A 3-month-old infant died following a 3-week illness that commenced with diarrhoea and vomiting, and produced progressive infarction of his small bowel. Post-mortem identified multiorgan arteritis of uncertain aetiology, giving rise to coronary artery occlusion and myocardial infarction as well as necrosis of the entire small bowel and other organs. Kawasaki disease and polyarteritis nodosa of infancy are proposed as possible aetiologies in this case.

Enterocolitis, Necrotizing↗
PubMedDate not supplied

Status of the MNSs antigens on human platelets.

A sensitive and specific radioimmunoassay was used to determine whether human platelets possess antigens of the MNSs blood group. Mouse monoclonal IgG anti-M and anti-N were purified by Staphylococcus protein A chromatography, labeled with 125I, and incubated with platelet pellets from donors of various MN phenotypes. Human IgG anti-M, -S, and -s were purified by absorption-elution, incubated with platelet pellets from donors of different MNSs phenotypes, washed, and incubated with 125I-labeled mouse monoclonal anti-human IgG. In both assays, the platelet pellets were centrifuged through phthalate ester oils and the radioactivity in the pellets was counted. Dose-response curves and ligand bound per cell indicated no significant difference in the binding of mouse or human anti-M and anti-N to platelets from donors of the MM, MN, or NN phenotype or of human anti-S and anti-s to platelets from donors of the Ss or ss phenotype. Contrary to many previous studies, our data indicate that the MNSs antigens are not expressed on the circulating human platelet. Therefore, antibodies to these antigens probably do not play a role in refractoriness to platelet transfusion.

Antigens, Surface↗
PubMedDate not supplied

Stimulation of pyloric contractions by intraduodenal triglyceride is persistent and sensitive to atropine.

Intraduodenal lipid infusion stimulates phasic and tonic pyloric contractions and suppresses antral contractions. This study determined: (i) whether this response is sustained over 90 min; and (ii) the role of muscarinic mediation of this response. Antropyloroduodenal motility was recorded in 17 healthy volunteers with a sleeve/sidehole manometric assembly. Subjects received either a 90 min intraduodenal infusion of saline or triglyceride (20% Intralipid) at a rate of 1 mL/min; 30 min after the start of this infusion, the eight subjects who received triglyceride were given intravenous atropine 15 micrograms/kg over 30 s, followed by a maintenance infusion of 4 micrograms/kg/h until the study was completed. Intraduodenal triglyceride infusion stimulated isolated pyloric pressure waves consistently, producing a median rate of 2.4 per min after 30 min of triglyceride infusion, compared with a median rate of 0 per min pre-infusion. In intravenous saline studies, there was a reduction (P < 0.05) in the median rate of isolated pyloric pressure waves to 1.3 per min at 90 min, when compared with pyloric pressure waves at 30 min. Atropine reduced isolated pyloric pressure waves to a median rate of 0 per min, significantly different from preatropine (P < 0.01) and from intravenous saline studies (P < 0.0001). These results indicate that the phasic pyloric response to intraduodenal lipid persists during 90 min stimulation, albeit with significant attenuation. In humans, muscarinic cholinergic blockade prevents the occurrence of triglyceride stimulated localized pyloric contractions.

Adult↗
PubMedDate not supplied

Intracranial EEG monitoring in Landau-Kleffner syndrome associated with left temporal lobe astrocytoma.

A 3 1/2-year-old boy developed partial complex seizures with right-sided motor activity, occasionally secondarily generalized at age 18 months. Initial EEG showed left-sided focal epileptiform discharges. Seizures became refractory to antiepileptic drugs (AEDs). At age 3 years, there was severe language deterioration consistent with Landau-Kleffner syndrome (LKS). At that time, an EEG showed almost continual generalized spikes and polyspikes, worse during sleep. Video-EEG showed generalized tonic seizures associated with generalized EEG ictal activity. Magnetic resonance imaging (MRI) showed a cystic and solid lesion of the left hippocampal and parahippocampal gyri without surrounding edema. Subdural strip electrodes under the left temporal and overlying the left frontal lobes demonstrated interictal spikes simultaneously in all recording contacts. Ictal EEG activity occurred in the temporal electrodes 0.2-1 s before appearing in the frontal electrodes. After left temporal lobectomy with subtotal resection of a low-grade astrocytoma, he had an immediate marked decrease in seizures. In 1 month he was seizure-free, and in 6 months had no further seizures and markedly improved language. These findings provide further evidence that left temporal structural epileptogenic lesions may contribute significantly to the pathophysiology of LKS.

Aphasia↗
PubMedDate not supplied

Contralateral temporal hypometabolism on positron emission tomography in temporal lobe epilepsy.

INTRODUCTION: No detailed case studies report lateralised hypometabolism on positron emission tomography (PET) contralateral to the epileptogenic focus in temporal lobe epilepsy (TLE). MATERIAL AND METHODS: We performed 18F fluorodeoxyglucose (FDG) PET in two intractable TLE patients. RESULTS: One had right temporal interictal spikes on electroencephalography (EEG) and a right medial temporal lobe lesion on magnetic resonance imaging (MRI). FDG-PET showed decreased uptake in the left temporal lobe. Right temporal ictal onset, with bilateral interictal epileptiform activity, occurred on intracranial EEG. He is seizure free after right temporal lobectomy and ganglioglioma resection. The second had right temporal lobe interictal and ictal EEG activity. MRI demonstrated right anteriomedial temporal increased T2 signal. Neuropsychology revealed bilateral cognitive dysfunction. FDG-PET showed left anterior temporal and lateral frontal hypometabolism. He is seizure free after right temporal lobectomy. CONCLUSION: These findings suggest that regional uptake asymmetry on FDG-PET may be give misleading lateralising information in TLE.

Adult↗
PubMedDate not supplied

Small liver fenestrae may explain the susceptibility of rabbits to atherosclerosis.

Rabbits fed cholesterol rapidly develop high serum cholesterol levels which lead to the development of atherosclerosis. This is related to the retention of cholesterol-rich chylomicron remnants in the circulation. In most animals, such as rats, chylomicron remnants are rapidly removed from the circulation by the liver. The first barrier to this removal is the fenestrated endothelium of liver sinusoids. Measurements made of a large number of sinusoidal fenestrae by scanning electron microscopy have shown the average diameters to be 89 nm in rats and 49 nm in rabbits. We postulate that the small size of endothelial fenestrae in the liver sinusoids of rabbits hinders the egress of chylomicron remnants from the sinusoidal blood, explaining the subsequent development of hypercholesterolemia and atherosclerosis.

Animals↗
PubMedDate not supplied

Response of aldosterone and 18-hydroxycorticosterone to angiotensin II in normal subjects and patients with essential hypertension, Conn's syndrome, and nontumorous hyperaldosteronism.

Dose-response curves relating plasma angiotensin II (AII) concentration during AII infusion to blood pressure (BP), to plasma aldosterone, and to plasma 18-hydroxycorticosterone were compared in normal subjects and in patients with essential hypertension, Conn's syndrome, and nontumorous hyperaldosteronism. The BP response was steeper than normal in patients with Conn's syndrome and essential hypertension. Before infusion, mean plasma aldosterone concentration was approximately four-fold higher in Conn's syndrome than in the normal group, while that of 18-hydroxycorticosterone was ninefold higher. Neither increased significantly during AII infusion. In essential hypertension, both corticosteroids were within the normal range, but their responses to AII infusion were greater than normal. In the three subjects with non-tumorous hyperaldosteronism, plasma aldosterone and 18-hydroxycorticosterone concentrations were raised, and their responses to AII infusion resembled those found in essential hypertension and were different from those found in Conn's syndrome. This suggests that nontumorous hyperaldosteronism is not a variant of Conn's syndrome. In the response to AII and in other ways, it is indistinguishable from essential hypertension.

18-Hydroxycorticosterone↗
PubMedDate not supplied

Viral and chemical tracer movement through contrasting soils.

Land treatment of animal or human waste can result in chemical and microbial contamination of shallow ground water and/or water-ways. We investigated the fate of a host-specific Salmonella bacteriophage and a nonreactive chemical (Br-) tracer when applied to large intact lysimeter soil cores (500 mm diam. by 700 mm high). The soils included a poorly drained Gley Soil and well-drained Pumice, Allophanic, and Recent Soils. A depth of 30 mm of water containing the bacteriophage and Br- was applied to the soil at a rate of 5 mm h(-1) followed by up to about 1.8 pore volumes of simulated rainfall. Resulting leachates, collected continuously over at least one pore volume were analyzed for the bacteriophage and bromide (Br-) tracers. Bromide moved uniformly through the Pumice and Allophanic Soils with peak concentrations at about 1 pore volume, while the bacteriophage was detected only at trace levels or not at all. In contrast, both Br- and bacteriophage tracers moved rapidly through Gley and Recent Soils, appearing early in the leachate and then tailing off. Such flow patterns in the Gley and Recent Soils are indicative of bypass flow. Coarse soil structure in the Gley Soil, and finger-flow due to water repellency in the sandy Recent Soil are considered responsible for the observed bypass flow in these two soils. Allophanic and Pumice Soils have finer, more porous soil structure leading to a predominance of matrix flow over bypass flow. This study suggests vertical movement of viruses varies significantly with soil type.

Animals↗
PubMedDate not supplied

Clinical, biochemical and genetic features of five extended kindred's with glucocorticoid-suppressible hyperaldosteronism.

Glucocorticoid-suppressible hyperaldosteronism (GSH) is an uncommon form of dominantly inherited hypertension caused by the inheritence of a chimaeric 11 beta-hydroxylase/aldosterone synthase gene. Affected individuals appear to have an increased risk of premature morbidity and mortality from stroke, but treatment with low doses of dexamethasone can completely reverse the biochemical and clinical features. We assessed the clinical and genetic features of 5 British kindreds with GSH, the largest collection outwith the United States, and determined the location of the crossover regions in the chimaeric gene of all 5 kindreds. All of the kindreds were of celtic origin, another feature peculiar to GSH. In total 19 out of 60 individuals screened by genotyping were found to possess the chimaeric gene and sequencing of the chimaeric gene revealed that all the crossover regions were within the exon 3- exon 4 region of, in keeping with previous studies, and three kindreds possessed indistinguishable chimaeric genes.

Chimera↗
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Successful transplantation of a lung allograft from a carbon monoxide-poisoning victim.

Donor availability remains the limiting factor to heart and lung transplantation. Donor selection criteria need to be continuously reassessed to expand the donor pool. The feasibility of organ donation from victims of carbon monoxide poisoning is unclear. We present a case of successful single lung transplantation from a carbon monoxide-poisoning victim.

Adult↗
PubMedDate not supplied

Effects of different levels of vitamin C intake on the vitamin C concentration in guinea pigs plasma and the effect of vitamin C intake on anaphylaxis.

The plasma ascorbate level after a single intraperitoneal dose of 25, 100 or 250 mg Na-ascorbate was followed up in vivo over a period of 24 hours. Intraperitoneal administration of Na-ascorbate caused a rapid increase of ascorbic acid plasma concentration. Maximum ascorbic acid plasma level was obtained 30 minutes after parenteral administration of the test dose. No great difference was found between the 12- and 24-hour ascorbic acid plasma values. The effect of Na-ascorbate on fatal anaphylaxis was also investigated in 18 guinea pigs. The animals treated with 281 mg/day Na-ascorbate rarely developed anaphylactic shock or the shock was of weaker intensity. Mortality was reduced from 40% (control group) to 11% when Vitamin C was given for four days before and one day after passive transfer of rabbit anti-HGG (human gamma globulin) antibody. A possible protective role of ascorbic acid by preventing anaphylaxis is discussed. Passive administration of ascorbic acid was found to protect guinea pigs from fatal anaphylaxis.

Anaphylaxis↗
PubMedDate not supplied

Breast-feeding support in a neonatal surgical unit.

The focus of this article is breast-feeding support for mothers of infants that have to be nursed in hospital. It examines previous studies and considers them alongside the findings of an anonymous customer-satisfaction survey. Indications are that a long-term commitment of resources is required if breast-feeding support for this high-risk population is to be improved.

Adult↗