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Biomedical subjects

R D Marshall

Publications and source records attributed to R D Marshall.

At least 73 records · Page 4Linked to original sources
PubMed1977

Some factors affecting the production, by cultured baby-hamster kidney cells, of BHK glycoprotein I which cross-reacts immunologically with Tamm-Horsfall glycoprotein.

Cultured baby-hamster kidney cells (BHK-21/C13), which are adapted to grow in suspension (strain 2P), roduce a glycoprotein, termed BHK glycoprotein I, which cross-reacts immunologically with hamster urinary (Tamm-Horsfall glycoprotein. BHK glycoprotein I was isolated in an electrophoretically (sodium dodecyl sulphate/polyacrylamide gel) homogeneous form by application of affinity chromatography to the medium in which cells had been cultured. Insolubilized anti-(Tamm-Horsfall glycoprotein immunoglobulin G) was used as the adsorbent. The amount of BHK glycoprotein I associated with the cultured cells was found by both radioimmunoassay and immunofluorescence to be related to the amount of Ca2+ in the medium and to the particular stage of the cell cycle. 5'-Nucleotidase was also shed by the cells into the culture medium in amounts related to the stage of the cell cycle. The turnover of hamster Tamm-Horsfall glycoprotein in vivo appeared to be considerably more rapid than can be accounted for by cell turnover. Hamster Tamm-Horsfall glycoprotein was shown to be ineffective in inhibiting agglutination of chicken erythrocytes caused by influenza virus.

Calcium↗
PubMed1977

The UDP-N-acetylglucosamine-asparagine-sequon N-acetyl-beta-D-glucosaminyltransferase activity in preparations of rough endoplasmic reticulum from regenerating rat liver.

The UDP-N-acetylglucosamine-asparagine-sequon N-acetylglucosaminyltransferase activity in preparations of rough endoplasmic reticulum from rat liver is less than 1% of that in preparations from rabbit liver. The activity of the enzyme is increased about 20-fold in preparations from regenerating rat liver within 48h after partial hepatectomy. A smaller, but still marked, increase (8-10-fold) occurs in preparations of rough endoplasmic reticulum from sham-operated rats.

Animals↗
PubMed1977

Acid dissociation constants of glycopeptides.

Glycopeptides containing mainly four amino acid residues in the sequence Asn-Leu-Thr-Ser, with small amounts of additional amino acid residues, were isolated from enzymic hydrolysates of hen's-egg albumin. Heterogeneity of the carbohydrate moiety was confirmed. Acid-base titrations showed that the alpha-amino group has a pKa value of 6.43 at 25 degrees C. The standard free engery and entropy changes associated with the ionization at 25 degrees C were 37.2kJ-mol-1 and -0.014kJ-mol-1- K-1 respectively. The complications arising in the interpretation of titration curves of the glycopeptides, which are heterogeneous with respect to the peptide chain, were considered and discussed in the light of the earlier suggestion that the titration curve of the glycopeptide might be interpreted as being due in part to a structure in which the hydroxyl group of the threonine residue is hydrogen-bonded to the beta-aspartamido oxygen atom [Neuberger & Marshall (1968) in Symposium on Foods - Carbohydrates and their Roles (Schultz, H.W., Cain, R.F. & Wrolstad, R.W., eds.), pp. 115-132, Avi Publishing Co., Westport, CT]. It is concluded that either the glycopeptides do not contain a hydrogen bond of that type, or, if they do, that it cannot be recognized by acid-base-titration studies.

Amino Acid Sequence↗
PubMed1976

Glycosylation in vitro of an asparagine sequon catalysed by preparations of yeast cell membranes.

Preparations of yeast cell membranes can catalyse in vitro the N-acetyl-beta-D-glucosaminylation of the asparagine sequon at residues 34--36 of bovine pancreatic ribonuclease A. The relevant glycopeptides were isolated from tryptic hydrolysates of the glycosylated ribonuclease and analysed. The donor used was UDP-N-acetyl-D-glucosamine, although the mechanism of the transfer is unknown. Mn2+ ions at concentrations of 25 mM double the activity of the enzymic transfer.

Acetylglucosamine↗
PubMed1976

UDP-N-acetyl-D-glucosamine-asparagine sequon N-acetyl-beta-D-glucosaminyl-transferase-activity in human serum.

Serum contains a sugar transferase which is able to catalyse the glycosylation in vitro of the asparagine residue present in the sequence Asn.Leu.Thr in bovine pancreatic ribonuclease. UDP-2-Acetamido-2-deoxy-D-glucose (UDP-N-acetyl-D-glucosamine) acts as a donor, although the mechanism of the transfer is unexplored. Spermidine and Mn2+, as well as CDP-choline, can act as activators for the reaction. Monoglycosylated ribonuclease (ribonuclease-GlcNAc) has been separated (23% yield) from unreacted ribonuclease A by affinity chromatography on a column of wheat-germ agglutinin bound to Sepharose, and characterised. A possible reason for the presence of the enzyme in serum is suggested.

Acetylglucosamine↗
PubMed1976

Tracheal dilatation.

Three cases of tracheal dilatation following prolonged ventilation through a tracheostomy tube with a conventional cuff are reported. The routine care of tracheostomies in the ITU at Northampton General Hospital is described. Possible causes for the development of dilatation are suggested and the symptoms and signs discussed.

Aged↗
PubMed1975

Enhancement of the activity of asparaginyl-tRNA synthetase by an activator from rabbit liver.

Asparaginyl-tRNA synthetase has been partially purified from acetone powders of rabbit liver. (NH-4)-2SO-4 fractionation was followed by chromatography of the enzyme on DEAE-cellulose. An activator separated from the enzyme. Further chromatography on Sephadex G-100 and G-200 showed that the latter consisted of two components. The smaller of these (mol wt is approximately equal to 35 000) possessed enzyme transfer activity but the larger one (mol wt 80 000-90 000) required the addition of activator before any enzyme transfer activity was demonstrable. The activator itself was devoid of transfer activity. After chromatography of crude extracts of asparaginyl-tRNA synthetase on Sepharose 4B the activity in the enzyme peak, which was of considerably larger molecular weight than any of the fractions found after purification could be enhanced by addition of the activator. None of the fractions of the enzyme or of activator catalysed any extensive asparagine-dependent ATP-PP-i exchange, either in the presence or the absence of added tRNA.

Amino Acyl-tRNA Synthetases↗
PubMed1975

Glycosylation of ribonuclease A catalysed by rabbit liver extracts.

Crude extracts of rabbit liver catalyse in vitro the transfer of N-acetylglucosamine from UDP-N-acetylglucosamine to bovine pancreatic ribonuclease A. The enzymic activity is contained in rough endoplasmic reticulum. It has an absolute requirement for a bivalent metal ion: Co-2+ greater than Mn-2+ greater than Ni-2+. Mg-2+ is ineffective. There is enzymic activity in the absence of detergent, but increased activity is observed in the presence of Triton X-100. The site of glycosylation of ribonuclease A is asparagine-34, and glycosylation occurs only at this point. These findings agree with the hypothesis that the sequence Asn-X-Thr(Ser) (where X may be one of a number of types of amino acid) is a necessary, but not sufficient, condition for N-acetylglucosaminylation of a protein-bound asparagine residue.

Acetylglucosamine↗
PubMed1975

Hiatal hernia repair by posterior gastropexy.

Posterior gastropexy was used in the repair of seventy-seven hiatal hermias from 1970 to 1975, after the fashion of Lucius D. Hill, of Seattle. The operations were performed by one author and reviewed by the other. The rationale and technique of the operation are discussed. Ten patients were lost to follow-up. Fifty-six patients were greatly imporved or cured, ten were imporved but still had some symptoms, while only one was unimproved. We conclude that posterior gastropexy is an effective, simple, and safe operation for the treatment of reflux associated with hiatal hernia.

Adult↗
PubMed1974

A more efficient use of hospital beds?

Faced with a shortage of trained nursing staff and a high wastage rate among learners the management of a district general hospital decided to close some of its acute beds. A beds committee attempted to minimize the effects of these closures by introducing a bed bureau, "pooling," and a simple system for forecasting waiting list admissions.The figures for recruitment and wastage of nurses improved, and a very high turnover per available bed was achieved. This increased efficiency in numerical terms was not mirrored by an improvement in the morale of the doctors and nurses working on the wards, who were subjected to new pressures and considered that at times the standard of patient care deteriorated.

Anxiety↗
PubMed1972

Glycoproteins.

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Amino Acid Sequence↗