Biomedical subjects
Publications and source records attributed to S J Butler.
Neonatal stroke may occur silently. Identification of potential embolic pathways unique to the neonate is important when investigating the aetiology of infarction and arterial occlusion, and preventing further episodes. This is a case report of an infant with venous thrombus embolising across the foramen ovale causing cerebral infarction and subclavian artery steal syndrome, without neurological signs.
klingon is a member of the Immunoglobulin superfamily and is expressed in a restricted pattern of neurons during embryonic neurogenesis and in the R7 photoreceptor precursor throughout its development. Starting from the H214 enhancer trap line, we identified a transcription unit, klingon, that encodes a putative protein of 528 amino acids and contains three C2-type Immunoglobulin-like domains followed by one fibronectin type III repeat. When Klingon is expressed in S2 tissue culture cells, it is associated with the cell membrane by a glycosyl-phosphatidylinositol linkage and can mediate homophilic adhesion. Genetic analysis has revealed that klingon is an essential gene that participates in the development of the R7 neuron. Ectopic expression of klingon in all neurons in a sevenless background can alter the position of the R8 rhabdomere.
We studied calcium (Ca), magnesium (Mg) mass transfer (MT) in 10 and lactate balance in 5 CAPD patients using standard dialysis solution [(ST) (Ca 1.75 mmol/l; Mg 0.75 mmol/l; lactate 35 mmol/l)] and with reduced Ca/Mg, high lactate solution [(LC) (1.25 mmol/l; 0.25 mmol/l; 40 mmol/l respectively)]. Exchanges were performed with 1.36% and 3.86% glucose solutions. MT was calculated as mmol/exchange. Ca MT was +0.96 and +0.39 with ST 1.36% and 3.86% glucose respectively. Serum ionised Ca (iCa++) levels were less than fluid Ca during these exchanges. With LC 1.36% glucose it was -0.66 when ICa++ was more than dialysate Ca, but +0.66 when iCa++ was less than dialysate Ca. Ca MT was negative with LC 3.86% glucose irrespective of iCa++ levels. All patients were hypermagnesaemic (mean 1.24 mmol/l. Mg MT was +0.21 and -0.04 with ST 1.36% and 3.86% glucose respectively and -0.62 and -1.13 with LC 1.36% and 3.86% glucose respectively. The difference between mean lactate gain and bicarbonate loss was less (-0.4) during exchange with LC 1.36% glucose. Mean plasma TCo2 and plasma pH did not differ between ST and LC solutions. We conclude that reduced Ca/Mg, high lactate solutions should reduce hypercalcaemia/magnesaemia and maintain a better acid base balance in CAPD patients who may require Ca/Mg containing phosphate binders.
Urogastrone was measured by radioimmunoassay in amniotic fluid obtained from 186 complicated pregnancies at 22 to 40 weeks gestation. Amniocentesis was performed for a variety of indications to obtain information about fetal lung maturity or bilirubin levels before induction of labour or caesarean section in various obstetric conditions. In 114 specimens lung phospholipids extracted from amniotic fluid were also assayed using two-dimensional thin layer chromatography. Urogastrone concentrations became measurable at approximately 30 weeks gestation and thereafter there was a 10-fold rise in concentrations between 30 and 40 weeks gestation. This increase in urogastrone concentration was positively correlated with a rise in phosphatidylcholine and phosphatidylglycerol concentrations and the phosphatidylcholine (lecithin)/sphingomyelin ratio (L/S). These results are compatible with a role for urogastrone in human fetal lung maturation.
The anti-helminthic drug suramin inhibited the basal high-affinity GTPase activity of both C6 BU1 glioma and NG 108-15 neuroblastoma x glioma hybrid-cell membranes with an IC50 (concentration causing half-maximal inhibition) value close to 30 micrograms/ml. This effect was shown to occur via a non-competitive mechanism in which the binding affinity of the G-proteins for GTP was not altered, but the maximal velocity of the subsequent hydrolysis was reduced. In NG 108-15 membranes, both opioid peptides and foetal-calf serum stimulated high-affinity GTPase activity in a pertussis-toxin-sensitive manner. These effects have previously been shown to be mediated by different G-proteins [McKenzie, Kelly, Unson, Spiegel & Milligan (1988) Biochem. J. 249, 653-659]. Suramin completely prevented the opioid-peptide-stimulated increase in GTP hydrolysis, but did not prevent the opioid peptide from binding to its receptor. Suramin, however, did not block the foetal-calf-serum-stimulated GTPase response. This selective action of suramin provides further evidence for distinct roles for two separate pertussis-toxin-sensitive G-proteins in signal transduction in NG 108-15 membranes and provides the first evidence for a selective effect of a drug on the functions of different G-proteins.
One quarter of 172 patients from two hospitals with no obvious disturbances of calcium homeostasis and with total serum calcium concentrations that were normal after adjustment for albumin concentration had low serum ionised calcium concentrations. The low values were not due to changes in pH but were associated with hypoalbuminaemia. Significant positive regressions of ionised calcium on albumin concentration were observed in patients from both hospitals and also in 48 healthy laboratory staff. Because the regressions did not differ between patients and healthy subjects the low ionised calcium values associated with hypoalbuminaemia are unlikely to have been of pathological importance. These findings indicate that interpreting serum ionised calcium concentrations in patients with a reduced serum albumin concentration on the basis of a reference range determined in subjects with a normal serum albumin concentration may be clinically misleading.
Explore the source record for details and available documents.
Guinea pig liver transglutaminase has been used to incorporate putrescine into horse heart cytochrome c. The native protein showed essentially no incorporation, while ethanol-denatured cytochrome c incorporated almost 1 mol putrescine per mol protein. No increase in this level of modification was obtained when maleylated cytochrome c and the tryptic peptides of cytochrome c were used as substrates. Analysis of the modified ethanol-denatured cytochrome c by tryptic cleavage and peptide isolation showed that glutamine-42 of the intact protein is the site of incorporation of radioactively labelled putrescine. Ethanol-denatured cytochrome c that was specifically modified at glutamine-42 by incorporated of putrescine could be readily renatured. The renatured modified protein showed reactivity with cytochrome c oxidase comparable to that of the original native protein.
Explore the source record for details and available documents.
Explore the source record for details and available documents.