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Biomedical subjects

J Roberts

Publications and source records attributed to J Roberts.

At least 595 records · Page 33Linked to original sources
PubMed1979

Status epilepticus. An uncommon hysterical conversion syndrome.

The distinction between hysterical and organically determined epileptic seizures may be more difficult than is sometimes supposed, and misdiagnosis can have dire consequences. Hysterical seizures may on occasions present as life-threatening crises requiring urgent and intensive treatment. Three such cases, each of which received the diagnosis of status epilepticus, are reported, and their management is discussed.

Adult↗
PubMed1978

Purification of indolyl-3-alkane alpha-hydroxylase by affinity chromatography on indolyl-agarose columns.

Indolyl-3-alkane alpha-hydroxylase was isolated from soil isolate organism, Pseudomonas XA, by affinity chromatography on indolyl-agarose, using different indole derivatives (L-tryptophan, N-acetyl-L-tryptophan, indole-3-carboxaldehyde and 3-indole-acrylic acid). With the exception of N-acetyl-L-tryptophan-agarose, excellent yields were obtained. The affinity chromatography step caused a 15-fold increase in the specific activity of the enzyme. The purity of indolyl-3-alkane alpha-hydroxylase was comparable to the preparations obtained by conventional isolation techniques; however, it showed a 7- to 10-times higher overall yield. Affinity purified indolyl-3-alkane alpha-hydroxylase exhibited essentially one band in polyacrylamide gel electrophoresis and on isoelectric focusing.

Chromatography, Affinity↗
PubMed1978

Amino acid sequence of the diazooxonorleucine binding site of Acinetobacter and Pseudomonas 7A glutaminase--asparaginase enzymes.

Acinetobactor glutaminase-asparaginase was treated with [6-14C]diazo-5-oxonorleucine, reduced with sodium borohydride, and cleaved with cyanogen bromide. Radioactivity was present only in a 96-residue-N-terminal peptide which eluted as the second peptide peak on Sephadex G-50. Radioactivity was released with the threonine in position 12 during automatic sequencing of this peptide. The amino acid sequence of a 60-residue tn-terminal segment and a 16-residue C-terminal segment of this peptide was determined. Pseudomonas 7 A glutaminase-asparaginase was treated with [6-14C]diazo-5-oxonorleucine and reduced with sodium borohydride. Radioactivity was released with the threonine in residue 20 during automatic sequencing of the whole enzyme. Analysis of 26 N-terminal residues showed that an 8-residue segment containing the radioactive threonine was identical with that in Acinetobacter glutaminase-asparaginase and in Escherichia coli asparaginase. Additional identical residues were noted in the N-terminal regions of these enzymes.

Acinetobacter↗
PubMed1978

Kinetics of uptake and activity in mouse liver of glutaminase coupled to desialated orosomucoid.

Desialised orosomucoid (alpha-1-acidic glycoprotein) was coupled to Pseudomonas 7A glutaminase-asparaginase by glutaraldehyde, iodinated and injected into mice. The half-life of radioactivity and glutaminase activity in plasma was about 7 min. Radioactivity and glutaminase activity in the liver reached a peak at about 20 min. The radioactivity in liver then declined with a half-life of about 20 min. Enzyme activity in liver declined with a half-life of about 10 min. The ratio of enzyme activity to radioactivity was lower in the liver than in plasma at all times during the experiment, indicating rapid hepatic inactivation of the enzyme. Uptake into the liver could be blocked by excess desialised orosomucoid. Glutamine levels in the liver were about 10% of normal for 44 min but returned to 50% of normal by 93 min. Intestines, kidney and spleen failed to exhibit any appreciable uptake of desialated orosomucoid glutaminase-asparaginase.

Animals↗
PubMed1978

Nonuniform cardiac sympathetic nerve discharge: mechanism for coronary occlusion and digitalis-induced arrhythmia.

This study examined nonuniform postganglionic cardiac sympathetic neural discharge as a possible mechanism involved in the production of coronary occlusion or ouabain-induced arrhythmias. After acute occlusion of the left anterior descending coronary artery in 12 cats, anesthetized with alpha-chloralose and pretreated with atropine, arrhythmia occurred within 3 min in eight animals; three of these died in ventricular fibrillation. In recordings from 15 nerves in the eight animals with arrhythmia, spontaneous discharge increased in nine nerves, decreased in five nerves, and showed no change in one nerve. This nonuniform neural discharge was associated with the development of arrhythmia after occlusion. In four of the cats, neural discharge did not change within the first 3 min after coronary artery occlusion and arrhythmia did not occur. Development of ouabain-induced arrhythmia was accompanied by a nonuniform pattern in the neural discharge (13 cats). This discharge may alter ventricular excitation and conduction to produce arrhythmia.

Action Potentials↗