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Biomedical subjects

R C Evans

Publications and source records attributed to R C Evans.

At least 55 records · Page 3Linked to original sources
PubMed1980

Spontaneous disappearance of large stones from the common bile duct.

Spontaneous disappearance of three large gallstones from the common bile duct is reported. One of the stones measured 15 mm in size and is the largest ever seen to pass into the intestine without perforation. The observation emphasizes the need for repeat diagnostic imaging of the biliary tract in patients who become free of symptoms before the intended operation.

Aged↗
PubMed1980

Sudden death in hypertrophic cardiomyopathy: associated accessory atrioventricular pathways.

Sudden death is a known but unpredictable complication of hypertrophic cardiomyopathy. We describe two patients who both had a strong family history of the disorder complicated by sudden death. Necropsy disclosed accessory bypass tracts, concealed in one and previously suspected in the other. One died from ventricular fibrillation and the other, who died outside hospital, had previously complained of palpitation. Arrhythmia complicating pre-excitation appears to be one of the factors responsible for sudden death in hypertrophic cardiomyopathy.

Adolescent↗
PubMed1976

Shunt blockage in hydrocephalic children: the use of the valvogram.

Shunt blockage in valve-dependent hydrocephalic children is not always recognised, as symptoms may be non-specific and signs inconclusive. Valvography is a simple, easily interpreted technique for the investigation of shunt patency in children with Spitz Holter values in the shunt system. The technique affords a simple, rapid method of demonstrating patency at the cardiac end of the shunt. Fifty-one valvograms have been performed in 36 children. In 25 obstruction of the lower end was demonstrated. The unreliability of some associated signs is demonstrated. No serious complications have been observed and the technique has proved an invaluable addition to the practical management of these children.

Catheterization↗
PubMed1976

Effect of Thiamine on Ethanol and Pyruvate Production in Helminthosporium maydis.

Growth of the fungus Helminthosporium maydis race T in a basal glucose-l-asparagine liquid medium, pH 5, is inhibited by thiamine-HCl. Analysis of the media for organic acids reveals that the extracellular pyruvate concentration decreases as the thiamine-HCl concentration of the medium increases. Extracellular ethanol, in contrast to pyruvate, increases in concentration as the thiamine-HCl concentration of the medium increases under both aerobic and anaerobic conditions.The changes in ethanol and pyruvate levels in the presence of thiamine-HCl occur via a thiamine-mediated increase in the activity of pyruvate decarboxylase but not alcohol dehydrogenase. This increase in pyruvate decarboxylase activity appears to be due to an increase in the quantity of enzyme present rather than an activation of pre-existing enzyme. Whereas thiamine-pyrophosphate stimulates pyruvate decarboxylase activity in vitro, thiamine-HCl has no effect. Neither thiamine derivative affects alcohol dehydrogenase activity. The increase in pyruvate decarboxylase activity which accompanies an increase in the thiamine-HCl concentration of the medium is correlated with a decrease in the level of intracellular pyruvate.

Journal Article↗
PubMed1976

The reliability of prediction of outcome in spina bifida.

The clinical findings in 85 neonates with spina bifida were given to two neurosurgeons and two paediatricians, who were asked to predict from them the length of survival and quality of survival with regard to intellect, locomotion and continence, without their knowing the actual outcome. All four clinicians correctly predicted the survival of infants with meningocele, closed myelocele and encephalocele. The paediatricians correctly predicted the survival of all infants with open myelocele who actually survived, but also included some who had died. The surgeons correctly predicted the deaths of all those with open myelocele who actually died, but expected a considerable number to die who in fact survived. All four clinicians were similar in their predictions of intellect: they underestimated the outcome in patients with successfully shunted hydrocephalus, they overestimated the intellect in patients who had developed intracranial infection and shunt blockage, and they largely underestimated the outcome in the patients who did not require shunts. They made correct predictions for limb and sphincter function in nearly all the survivors. This investigation underlines the problem of selection for treatment caused by the inability to predict the complications of hydrocephalus and infection. Reasons for the differences between the expectations of the paediatricians and surgeons, and the implications of the results of this study for selection for surgery are discussed. It is suggested that limb paralysis and incontinence ought not to be considered as factors excluding infants from treatment.

Child↗
PubMed1975

The use of the valvogram for the detection of shunt blockage in hydrocephalic children.

Valvography is a simple, safe, rapid, easily interpreted technique for the investigation of possible blockage of the distal end of the shunt system containing a Spitz-Holter valve. Details are presented of 64 investigations in 46 children, 30 of which demonstrated distal obstruction of the shunt system. The unreliability of some physical signs is discussed. No serious complications were encountered and the procedure has proved to be a valuable addition to the practical management of shunt-dependent children.

Cerebrospinal Fluid Shunts↗