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Biomedical subjects

G M Sobala

Publications and source records attributed to G M Sobala.

12 recordsLinked to original sources
PubMed1991

Screening dyspepsia by serology to Helicobacter pylori.

Owing to limited endoscopy resources, various screening strategies for endoscopy have been proposed. Helicobacter pylori can be detected with high sensitivity and specificity by serology, and therefore we assessed the effects on diagnostic accuracy and endoscopic workload of a policy of screening clinic patients with dyspepsia before endoscopy by a strategy based on age, Helicobacter pylori serology, and use of non-steroidal anti-inflammatory drugs. 1153 patients were studied, of whom 842 were of known histological H pylori status (histology group) and 293 had serum assessed prospectively by in-house and commercial ELISAs for detection of IgG antibodies to H pylori. Overall, the screening strategy would have reduced endoscopy workload by 23.3% (95% confidence interval 20.9-25.8%) and would have had a sensitivity for detection of peptic ulcer of 97.4% (94.5-99.1%). No peptic ulcer or malignant disease was missed in the patients studied prospectively, but 6 of 192 peptic ulcers in the histology group would have been missed. A policy of screening young dyspeptic patients for H pylori by serology is more sensitive than symptom-based screening strategies, and may have an important role in reducing endoscopy workload.

Adolescent↗
PubMed1991

Gastric juice ascorbic acid: effects of disease and implications for gastric carcinogenesis.

N-nitroso compounds (NOC) are strongly implicated in the causation of cancer of the stomach and it has been suggested that ascorbic acid might reduce the risk of gastric cancer by preventing their formation within gastric juice. However, until recently there have been no measurements of gastric juice ascorbic acid concentrations. We have measured both gastric juice ascorbic and total vitamin C (ascorbic acid and dehydroascorbic acid). Our findings suggest that ascorbic acid is secreted into the gastric lumen so that gastric juice concentrations are often greater than those in plasma. Gastric pathology affects this secretion, leading to values in gastric juice that are lower than plasma levels. Stimulation of gastric secretion does not raise vitamin C concentrations in individuals whose values are initially low. The role of ascorbic acid in preventing formation of NOC and protecting against gastric cancer is discussed in the light of these findings.

Ascorbic Acid↗
PubMed1991

Levels of nitrite, nitrate, N-nitroso compounds, ascorbic acid and total bile acids in gastric juice of patients with and without precancerous conditions of the stomach.

To determine the relevance of gastric juice factors to gastric carcinogenesis, 56 patients with unoperated stomachs undergoing endoscopy for dyspepsia had gastric juice aspirated and analysed for pH, ascorbic acid, total bile acids, nitrite, nitrate and total nitroso compounds (NOCs). Plasma was obtained for vitamin C estimation. Antral and body biopsies were assessed for gastritis, Helicobacter pylori, atrophy and intestinal metaplasia (IM). Patients with chronic atrophic gastritis (n = 17) had lower gastric juice ascorbic acid concentrations (P less than 0.001), higher pH (P less than 0.05) and higher incidence of H. pylori infection (P less than 0.001) than normal subjects (n = 12). Patients with reflux gastritis (n = 9) had higher total bile acids (P less than 0.01). Patients with chronic gastritis and IM (n = 11) had higher gastric juice pH (P less than 0.01) and total bile acid concentrations (P less than 0.05), and lower gastric ascorbic acid concentrations (P less than 0.01) than those with chronic gastritis and no IM (n = 24). In chronic gastritis, high nitrite concentrations were associated with high pH (P less than 0.01). However, there were no significant differences in plasma vitamin C or gastric nitrite, nitrate or total NOC concentrations in relation to gastric histology. We conclude that the premalignant condition IM is associated with H. pylori infection, low gastric ascorbic acid levels and elevated total bile acids, but not to elevation in nitrite or total NOCs in fasting gastric juice.

Adult↗
PubMed1991

Acute Helicobacter pylori infection: clinical features, local and systemic immune response, gastric mucosal histology, and gastric juice ascorbic acid concentrations.

The symptomatology of a case of acute infection with Helicobacter pylori is described, together with the accompanying changes in gastric mucosal histology, local and systemic humoral immune response, and gastric ascorbic acid concentration. The patient was an endoscopist, previously negative for the carbon-14 urea breath test, who had a week of epigastric pain and then became asymptomatic. H pylori was detected by culture of antral biopsy specimens and was still present after 74 days. Five days after infection the histological findings showed acute neutrophilic gastritis; by day 74 changes of chronic gastritis were evident. The patient seroconverted by IgG enzyme linked immunosorbent assay by day 74, but a mucosal IgM and IgA response was evident as early as day 14. Infection was accompanied by a transient hypochlorhydria but a sustained fall in gastric juice ascorbic acid concentration.

Acute Disease↗
PubMed1990

Gastric epithelium in the duodenum: its association with Helicobacter pylori and inflammation.

Duodenal biopsy specimens from 471 adults and 47 children were examined to determine the prevalence and distribution of gastric epithelium in the duodenal bulb in relation to age, gender, gastroduodenal inflammation, smoking, alcohol and consumption of nonsteroidal anti-inflammatory drugs (NSAID). Gastric metaplasia was present in the anterior wall duodenal biopsy specimen in 31%, was significantly less common in patients under 17 than in adults, and was more common in males than females. In sixty two adults who underwent multiple radial duodenal biopsy gastric metaplasia was randomly distributed around the duodenal circumference; sixty three per cent of the patients with gastric metaplasia found on multiple biopsy were detected by just the anterior biopsy. Gastric metaplasia was not obviously associated with alcohol, cigarette, or NSAID consumption. While the presence of gastric metaplasia was associated with adulthood, male sex, and low fasting gastric juice pH, its extent was associated with active duodenitis and Helicobacter-associated gastritis. On logistic regression, gastric metaplasia in the duodenum and gastric Helicobacter pylori were independent predictors of active duodenitis, but were not significantly associated with inactive duodenal inflammation. H pylori was observed in duodenal biopsy specimens from 32 patients, all with active duodenitis; bacteria were present only on foci of gastric metaplasia, and were more likely to be seen when the metaplasia was extensive. It is proposed that inflammatory injury to the duodenal mucosa by H pylori may stimulate the development of further gastric metaplasia, and that the area of duodenum susceptible to colonisation with H pylori may therefore increase progressively until mucosal integrity is compromised and ulceration supervenes.

Adolescent↗
PubMed1990

Reflux gastritis in the intact stomach.

Gastric biopsy specimens from patients who have undergone gastric surgery frequently exhibit foveolar hyperplasia, oedema, vasodilatation and congestion, and a paucity of inflammatory cells as consequences of entero-gastric reflux. Similar, albeit generally milder, changes were found in 47 of 316 (15%) non-surgical patients undergoing endoscopy for dyspeptic symptoms. To relate these changes to bile reflux or other potential gastric irritants the total bile acid concentration was measured in samples of fasting gastric juice, and the use of a symptom questionnaire ascertained the patients' cigarette consumption, use of non-steroidal anti-inflammatory drugs (NSAIDs), and alcohol intake. When patients with reflux gastritis were compared with normal controls (n = 91), significant increases in associated peptic ulceration and NSAID use were found in the group with reflux, but no increases in bile acid concentrations. Indeed, only one patient had evidence of duodenogastric reflux. It is concluded that most cases of "reflux gastritis" in the intact stomach are not due to reflux of bile. Our findings indicate an important pathogenic role for long term NSAID use, in what might be usefully termed type C or "chemical" gastritis.

Adolescent↗
PubMed1989

Ascorbic acid in the human stomach.

Ascorbic acid, the reduced form of vitamin C, may protect against gastric cancer. Accordingly, this study assessed the variability of ascorbic acid and vitamin C in the gastric juice of 77 patients with dyspepsia. There was a vitamin C concentration gradient from gastric juice down to plasma in subjects with normal gastric mucosa, but not in those with chronic gastritis. Patients with chronic gastritis had significantly lower gastric concentrations of vitamin C and ascorbic acid, and ascorbic acid concentrations were especially low in subjects with hypochlorhydria. The presence of the concentration gradient suggests that a mechanism for the secretion of vitamin C into the stomach exists. This is compromised by chronic gastritis. The very low ascorbic acid concentrations in hypochlorhydria may be a consequence of oxidation by bacterial nitrite. Those patients who by the Correa model are at greatest risk for gastric cancer have the lowest gastric levels of ascorbic acid.

Adult↗
PubMed1989

Does the endoscope control head need to be disinfected between examinations?

An evaluation was made of the incidence of contamination of endoscope control heads during gastroduodenoscopy and colonoscopy, and of the efficacy of a simple disinfection technique. Contamination of the control heads occurred in 4 out of 17 examinations. Scrubbing in detergent followed by wiping with swabs impregnated with 70% isopropyl alcohol and 2% chlorhexidine achieved adequate disinfection of artificial heavy contamination of the control head. The endoscope control head represents a potential source of cross-infection and should not be neglected in any cleaning procedure.

1-Propanol↗