M. Garamszegi

13C-Urea breath test is superior in sensitivity to detect Helicobacter pylori infection than either antral histology or rapid urease test.

There is no single technique which fulfils the criterion for a reference method to detect Helicobacter pylori (Hp) infection. The aim was to compare the results of antral histology (H), rapid urease test (U) and urea breath test (UBT) from antral biopsy samples in patients having gastric or duodenal lesions during upper GI endoscopy. We used the following methods: 1) biopsy specimens for histology (Warthin-Starry staining); 2) rapid urease test; and 3) 13C-urea breath test with infrared spectrometry. The total number of patients was 166 examined by H, U, and UBT. H, U and UBT were negative (-) in 64 patients and positive (+) in 51. The true positivity and false negativity (%, number of patients in parentheses) of each method based upon the positivity of the other two tests were: H+, U+ (54): UBT+, 94.4% (51) and UBT-, 5.6% (3); H+, UBT+ (57): U+, 89.5% (51) and U-, 10.5% (6); U+, UBT+ (65): H+, 78.5% (51) and H-, 21.5% (14). If Hp infection is considered to be positive when at least two tests detect the presence of Hp, UBT shows the highest sensitivity in comparison to histology of biopsy specimens and urease test. UBT is highly recommended as a screening test for Hp infection in patients presenting upper GI endoscopic alterations.

Mechanisms of vagal nerve in gastric mucosal defense: unchanged gastric emptying and increased vascular permeability.

Gastric cytoprotection in response to different agents (prostaglandins, carotenoids, etc.) failed to occur after surgical vagotomy. Decreased gastric emptying and the increased vascular permeability were tested in ethanol-treated rats without and with bilateral surgical vagotomy. The experiments were carried out on Sprague–Dawley rats. The animals were fasted for 24 h before experiments. Bilateral surgical vagotomy or only laparatomy were carried out at 30 min before administration of ethanol (96%, 1 ml). The animals were killed at 0, 1, 5, 15, and 60 min after ethanol administration, when the number and severity of gastric mucosal lesions were noted. In another series of experiments, the animal received Evans blue (1 mg/100 g) i.v. 15 min before killing. The gastric contents were collected and the glandular mucosa was scraped. Evans blue was extracted in chloroform, and its concentration was spectrophotometrically measured. It has been found that (a) both number of lesions and severity of ethanol-induced gastric mucosal damage were larger at each time period in surgically vagotomized rats than in rats with intact vagal nerves; (b) the increased vascular permeability was significantly higher in gastric mucosa at an early period in surgically vagotomized rats compared to rats with intact vagal nerve; (c) the increased vascular events preceded the development of macroscopic appearance of gastric mucosa damage in both groups of animals; and (d) the time-related response were the same in both groups of animals. It is concluded that increased vascular permeability, but not gastric emptying, probably has some role in the failure of the development of gastric cytoprotection in surgically vagotomized rats.

Statistical interpretation of the antisecretory effect of famotidine measured by intragastric pH-metry

Objective: Intragastric pH-metry is widely used to evaluate the efficacy of antisecretory drugs, but statistical interpretation of the measurements has not yet been standardised. Methods:The effects of single morning (N = 9) or evening (N = 7) doses of the H2-receptor antagonist famotidine, 20 mg (QUAMATELR, Gedeon Richter, Hungary) were compared by 24-hour intragastric pH-metry in hyperacid patients, in a prospective, controlled clinicopharmacological study. Intragastric pH was repeatedly measured with or without administration of famotidine, and {1} the minute to minute median pH values were calculated. Results:{2} Both treatments significantly reduced gastric acidity according to the “traditional” parameters of the time at pH ≥ 3, or median pH in the first 12 hours. Famotidine treatment in the evening was more effective than in the morning (634 vs 463 min or 5.22 vs 3.10). The morning and evening treatment groups did not differ from each other in these parameters when compared on the days without famotidine. {3} After demonstration of the significant differences between the treatment vs control days, and morning vs evening administrations we applied the Pattern Recognition by Independent Multicategory Analysis (PRIMA) method to select the most sensitive parameters for evaluation of the H2-receptor antagonist drug effect. The PRIMA method was developed to determine the sensitivity of each statistical parameter analysed in a comparison of different groups (discriminating power), and to determine the separability of groups using several parameters concomitantly (separation of groups). The mean pH, the period at pH ≥ 3, and the duration of pH-increase ≥ 1 on the day of treatment compared to the control day were found to be the most sensitive parameters both in demonstrating H2-receptor antagonist effect and in differentiation of morning and evening doses. {4} High separability of morning and evening treatment groups was achieved using these three parameters concomitantly according to the PRIMA method.Conclusion:This method may be of value in other clinical or clinicopharmacological trials to standardise the statistical analysis of data by selection of the most sensitive parameters for comparison of the patient groups. In subsequent studies it might also increase the sensitivity of discrimination by concomitant analysis of different parameters using the smallest appropriate number of patients.

Dynamism of cytoprotective and antisecretory drugs in patients with unhealed gastric and duodenal ulcers

Abstract A continuous multiclinical, randomized and prospective study has been carried out in our department to compare the efficacy of different cytoprotective (sucralfate, DE‐NOL, Vitamin A) and antisecretory drugs (atropine, cimetidine, ranitidine, famotidine, pirenzepine) on ulcer healing in patients with chronic gastric ulcer (GU) and duodenal ulcer (DU).