Showing papers by "Anthony P. Corfield published in 1993"

The roles of enteric bacterial sialidase, sialate O-acetyl esterase and glycosulfatase in the degradation of human colonic mucin

Abstract: Sialidase activity in normal faecal extracts showed a preference for mucin-related glycoprotein and oligosaccharide substrates, but the presence of two or moreO-acetyl esters at positions C7–C9 on the sialic acids retarded the rate of hydrolysis A specific sialateO-acetyl esterase was detected with a lower total activity relative to sialidase with mucin substrates and having a pH optimum of 78 and aKM of approximately 1mm sialateO-acetyl ester A specific glycosulfatase activity was found in faecal extracts using the substrate lactit-[3H]ol 6-O-sulfate with a pH optimum of pH 50 and aKM of approximately 1mm

Helicobacter pylori Infection in Elderly People: Correlation between Histology and Serology

Abstract: A hundred elderly dyspeptic patients were studied to assess the prevalence of Helicobacter pylori infection and the correlation between histological and serological findings. Eighty-one per cent of the patients with gastritis and 63% with gastric ulcer were H. pylori positive. All patients who had H. pylori negative gastritis and gastric ulcers were on nonsteroidal anti-inflammatory drugs (NSAIDs). There were 24 patients who had evidence of H. pylori infection and were on NSAIDs. H. pylori positive patients had more dyspeptic symptoms in comparison with those who were H. pylori negative. In patients who were taking NSAIDs, the presence of severe active gastritis seemed to correlate with the presence of H. pylori but not with the use of NSAIDs. Serology had a sensitivity of 90% and a specificity of 93% with a negative predictive value of 86%. There was a significant correlation between IgG titre and the degree of inflammation and H. pylori infection. We conclude that H. pylori gastritis is the commonest histopathological finding in elderly dyspeptic patients. H. pylori infection may be an important risk factor in elderly patients who take NSAIDs, increasing their risk of gastric ulcer. H. pylori serology in elderly people has a high sensitivity and specificity comparable with those in young age groups.

Sialic acids in human gastric aspirates: detection of 9-O-lactyl- and 9-O-acetyl-N-acetylneuraminic acids and a decrease in total sialic acid concentration with age.

Abstract: 1. The total sialic acid content of human gastric aspirates was measured using a colorimetric assay. Care was taken to optimize the assay and to eliminate interference. 2. The sialic acid content of gastric aspirates collected under resting conditions from 77 patients with non-ulcer dyspepsia was found to decrease with age from > 100 micrograms/ml at 25 years and younger to < 20 micrograms/ml above 70 years of age. 3. Analysis of the sialic acids by gas chromatography, mass spectrometry and thin-layer chromatography showed the presence of N-acetylneuraminic acid and two O-acylated derivatives, 9-O-acetyl- and 9-O-lactyl-N-acetylneuraminic acids. These forms were predominantly glycosidically bound. 4. Thin-layer chromatographic analysis of individual aspirate samples showed that the O-acetylated sialic acids were present in all samples, with a maximum of 25% and a minimum of 5% of the total sialic acids.

Role of Serology in Monitoring Treatment for Helicobacter pylori Infection in Elderly Patients

Abstract: Fifteen elderly patients with type B gastritis caused by Helicobacter pylori infection were treated with triple therapy consisting of colloidal bismuth subcitrate, amoxycillin and metronidazole. All were followed up every 6 weeks for 3 months. After triple therapy, eradication of the infection was confirmed in 12 patients (85%) by histology and bacteriology. In this group, a significant reduction in IgG antibody levels against H. pylori was detected (p < 0.001). In a control group of 15 patients with type B gastritis who received no antibacterial treatment, the specific IgG antibody titre remained unchanged during 3 months of follow-up. We conclude that this simple and noninvasive serological test would be suitable for follow-up after treatment of H. pylori infection in elderly patients.

S20.5 Changes in the biosynthesis of mucin oligosaccharides in human cancer cells

Abstract: Mucus glycoproteins, as found in mucus, are assembled from subunits via the agency of disulphide bonds. Our goal is to understand this assembly in terms of the organisation and interaction of the distinct glycosylated and naked domains within the subunit. We have studied the fragmentation of whole mucins and subunits by a variety of protein core cleaving reagents. The distribution of fragment size and molecular weight after degradation has been assayed with light scattering, rate zonal-centrifugation, electron microscopy and agarose gel electrophoresis. A novel feature of our data is evidence for a protease sensitive domain, present in macromolecules of Mr>10 × 106 which is involved in a supramolecular assembly resulting in molecules of Mr 2 0 3 0 x 106. Antibodies raised to the intact mucin are primarily targeted at this site which is also susceptible to reduction of disulphide bonds, though it is not disrupted by chaotropic agents such as 6 M guanidinium Chloride or detergents such as 0.1 M SDS. The presence of two other distinct proteinase susceptible domains can also be detected in trypsin digestion experiments. One domain is cleaved over a period of 10 h leaving a fragment Mr 2 . 5 5 x 10 ~ whereas further extremely slow degradation observed over 3 0 4 0 h yields a disperse group of fragments of average Mr 1.3 x 106. A coherent model for the architecture of these mucins, based on these data, will be presented.