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Biomedical subjects

G R Gray

Publications and source records attributed to G R Gray.

At least 109 records · Page 6Linked to original sources
PubMed1978

Proteins containing reductively aminated disaccharides: chemical and immunochemical characterization.

Synthetic glycoproteins can be prepared by reductive amination of proteins and reducing carbohydrates in the presence of sodium cyanoborohydride. The reaction proceeds readily in aqueous solution at pH 6--9 to give high degrees of substitution. The degree of substitution can be determined by amino acid analysis, as the 2 degrees amine linkage formed with the epsilon-amino groups of lysine is stable to acid-catalyzed protein hydrolysis conditions. Antisera have been obtained to bovine serum albumin conjugates containing reductively aminated cellobiose, lactose, and maltose. Preliminary experiments demonstrate that antiserum to the cellobiose-BSA conjugate is hapten-specific, and the structural features of the hapten recognized by the antibodies were established by hapten inhibition experiments. These studies demonstrate that antibodies recognize both the terminal beta-glucosyl and acyclic reduced glucosyl residues.

Amination↗
PubMed1978

Long term cimetidine in the management of severe duodenal ulcer dyspepsia.

Sixty patients who had been referred for elective ulcer surgery, and in whom a remission had been induced, entered a prospective double blind controlled trial of a single daily dose of 400 mg of cimetidine given at bedtime, or placebo. Eighty per cent of patients receiving placebo suffered symptomatic relapse and recurrence of duodenal ulceration at endoscopy within 6 months. The mean interval to relapse was 10 weeks. On the other hand, only 27 percent of patients had a recurrence during the 6-month period on low dose cimetidine therapy. No significant toxic or other side effects which could be attributed to the drug were observed.

Adult↗
PubMed1977

Acetylated methylmannose polysaccharide of Streptomyces.

A polysaccharide composed of 3-O-methyl-D-mannose and D-mannose in a molar ratio of approximately 10:1 and containing 3 to 4 esterified acetyl residues has been isolated from Streptomyces griseus. This acetylated methylmannose polysaccharide (AMMP) is similar to the methylmannose polysaccharide (MMP) of Mycobacterium smegmatis (Gray, G. R., and Ballou, C. E. (1971) J. Biol. Chem. 246, 6835-6842) in its size and composition, the absence of acidic or basic groups, and the lack of a reducing end. It is different, however, in its content of esterified acetyl residues, and it is slightly different in its structure and in its gel filtration properties. The structure of AMMP has been established by proton magnetic resonance spectroscopy, and by combinations of methylation analysis and Smith degradation utilizing non-radioactively labeled polysaccharide and [3H]methyl-labeled polysaccharide obtained from cells grown in the presence of L-[methyl-3H]methionine. It is concluded that AMMP is a linear, nonreducing, neutral polysaccharide composed of a terminal D-mannose residue linked alpha(1 leads to 4) to a chain of 10 consecutive alpha(1 leads to 4)-linked 3-O-methyl-D-mannose residues. The reducing terminal 3-O-methyl-D-mannose residue exists, at least in part, as its alpha-methyl glycoside. The positions of attachment of the ester residues have not been established.

Acetylation↗
PubMed1977

Lectin purification on affinity columns containing reductively aminated disaccharides.

A method is described for isolating lectins in pure form and quantitative yield in a single step by affinity chromatography on aminoethyl polyacrylamide gels containing reductively aminated disaccharide residues. The affinity columns were prepared in two steps: (a) direct reductive amination of the disaccharide and aminoethyl gel with sodium cyanoborohydride in aqueous solution at pH 9; (b) N-acetylation of excess amino groups. Affinity columns prepared by reductive amination of lactose, melibiose, maltose, and di-N-acetylchitobiose were used to purify the following lectins: lactose, peanut, castor bean; melibiose, Bandeiraea simplicifolia; maltose, jack bean, common lentil; di-N-acetylchitobiose, wheat germ. These columns are extremely stable, have good flow rates, and high binding capacities.

Chromatography, Affinity↗
PubMed1977

Oral cimetidine in severe duodenal ulceration. A double-blind controlled trial.

40 adult outpatients with active endoscopically proven duodenal ulceration, who would otherwise have merited elective ulcer surgery, entered a double-blind trial of either cimetidine (1g/day) or placebo. After twenty-eight days, 17 of 20 (85%) patients receiving cimetidine showed ulcer healing, compared with 5 of 20 patients receiving placebo (p less than 0.0005). Patients receiving cimetidine had significantly more pain-free days and pain-free nights than those receiving placebo. There was good correlation between ulcer healing and symptomatic relief (p less than 0.0005).

Administration, Oral↗
PubMed1976

Extragastric gastrinoma or G-cell hyperplasia of the antrum? The preoperative diagnosis in a case of hypergastrinaemia.

A patient is described with recurrent peptic ulceration, evidence of hypersecretion of gastric acid and excess circulating gastrin. The preoperative differentiation between extragastric "gastrinoma" and G-cell hyperplasia of the pyloric antrum as a source for the hypergastrinaemia can be made by immunofluorescent staining of an antral biopsy for "gastrin cells", and by measuring the response of the gastric antrum to an amino acid meal or secretion infusion stimulus. The site of excessive gastrin production determines the nature of the surgery required. A classification of recurrent peptic ulceration types is suggested.

Amino Acids↗
PubMed1976

Simultaneous inheritance of mutant isoenzymes of erythrocyte pyruvate kinase associated with chronic haemolytic anaemia.

The heterogeneity of pyruvate kinase (PK) deficiency associated with hereditary haemolytic anaemia is emphasized by studies of a kindred harbouring two distinct mutant forms of this enzyme, both of which were kinetically defective with markedly decreased affinities for the substrate, phosphoenolypyruvate. The two isoenzymes, designated PK-Vancouver1 and PK-Vancouver2, were primarily distinguishable from one another by differences in maximum in vitro activities and by variations in response to fructose-I,6-diphosphate activation. When combined in proband erythrocytes to the exclusion of any normal PK, the isoenzymes were associated with a severe chronic haemolytic process with many of the features of PK deficiency of the more common quantitative type. Clinical laboratory screening tests for detecting PK deficiency may be falsely negative or equivocal in such cases.

Anemia, Hemolytic, Congenital↗
PubMed1975

Immunotherapy of cancer: tumor suppression and regression by cell walls of Mycobacterium phlei attached to oil droplets.

Components of mycobacterial cell wall(s) (CW) attached to oil droplets were evaluated for their ability 1) to inhibit the growth of line-10 tumor transplants in the skin of syngeneic guinea pigs when inoculated together with 10(6) tumor cells (suppression experiments) and 2) to regress established 7-day-old intradermal tumors and eradicate microscopic lymph node metastases upon injection into the tumors (regression experiments). CW and cell-wall skeleton (CWS) preparations from Mycobacterium phlei, a fast-growing saprophyte of group IV of the atypical mycobacteria, suppressed tumor growth in essentially all animals when 37.5-mug doses were administered; at a dose of 300 mug, they cured 50-60% of the animals in regression tests. The addition of 300 mug of a purified trehalose mycolate, isolated from M. tuberculosis strain Aoyama B, to 300 mug M. phlei CW or CWS preparations significantly increased their tumor regressive potency to provide cure rates to about 90%. Because M. phlei can be propagated more readily, it can be used advantageously in place of BCG to prepare stable, non-living immunologic adjuvants of defined composition and consistently high potency to meet the need for standards with minimal residual malignant disease.

Animals↗