[Is the measurement of carcinoembryonic antigen still indicated in digestive cancers?]

Carcinoembryonic antigen (CEA) is not useful for detecting asymptomatic cancer. Its sensitivity and specificity are not high. For some cancers, antigen levels at the time of diagnosis provide more precise prognosis than staging alone. Regular determination of CEA is useful as a method of surveillance after surgery for cancer in the colon and in the rectum. Unfortunately the clinical gain of detecting postoperative relapses is low since curative surgical treatment is usually impossible.

[Pathogenic heterogeneity of Barrett's ulcers. Apropos of 38 case reports]

Barrett's ulcer is thought to develop in the columnar epithelium of Barrett's esophagus. In our series there is evidence that at least some Barrett's ulcers develop in squamous epithelium which may correspond to islets within Barrett's esophagus; in other cases Barrett's mucosa may surround a preexisting reflux-induced ulcer and thus transform it into Barrett's ulcer. In some individual cases of Barrett's ulcer development of the ulcer primarily in the columnar epithelium could not be ruled out. These ulcers may be produced by local acid secretion, by acid or alkaline gastroesophageal reflux in patients with reduced resistance of the columnar epithelium. Exceptionally, Barrett's ulcer may result from local irritation by medication (pill-induced ulcer) or by nasogastric intubation.

Combined esophageal and gastric pH-metry in healthy volunteers. Influence of cable through LES and effect of misoprostol

In order to evaluate whether combined esophageal and gastric pH-metry is feasible without interference due to the transcardial cable, four 24-hr ambulatory esophageal pH-metries were carried out in seven healthy volunteers in a randomized order. In two studies only one glass electrode was used. It was placed 5 cm above the lower esophageal sphincter. In the two other studies an additional electrode was placed in the corpus region 10 cm below the lower esophageal sphincter. In order to obtain a wide range of pH values, misoprostol (400 micrograms) was given at 9 AM and 9:15 PM in two studies. In the two other studies placebo was given. Misoprostol exerted only a weak and short-lasting effect on gastric acidity. The four measuring conditions did not differ with respect to medians of esophageal reflux time and duration of single reflux episodes, Kendall's coefficient of concordance yielded a high reproducibility for both variables (P less than 0.0025). Thus, combined esophageal and gastric pH-metry is feasible and highly reproducible.

Effects of hCGRP I and II on gastric blood flow and acid secretion in anesthetized rabbits

Effects of intravenously administered human calcitonin gene-related peptides (hCGRP) I and II on regional blood flow and gastric acid secretion were examined in barbiturate-anesthetized rabbits. Blood flow was measured by injection of radioactively labeled microspheres at 0, 10, 20, 30, and 60 min. hCGRP I and II and vehicle were infused intravenously in five rabbits in rising doses of 0.01 (0-10th min), 0.03 (11-20th min), and 0.1 microgram.kg-1.min-1 (21-30th min). hCGRP I and II increased gastric blood flow dose dependently. Moreover, hCGRP I raised regional conductance (inverse of vascular resistance) in the stomach, duodenum, heart, brain, and skeletal muscle. As a result of the increased total peripheral conductance the mean arterial pressure was reduced, but the cardiac output remained unchanged. hCGRP II increased blood flow and conductance selectively in the stomach and the pancreas. The total peripheral conductance and mean arterial pressure remained unchanged. Apparently, hCGRP II exerts a more localized effect on the stomach than hCGRP I. hCGRP I and II did not affect basal gastric acid secretion. Pentagastrin-stimulated acid secretion was increased by 28% with hCGRP I (0.025 micrograms.kg-1.min-1) and decreased by 27% with hCGRP II (0.025 micrograms.kg-1.min-1). The inverse effect of hCGRP I and II and the parallel stimulation of blood flow brought about with hCGRP I and II indicate a different mode of action of the peptides on gastric blood flow and gastric acid secretion.

Intragastric behavior and absorption kinetics of a normal and "floating" modified-release capsule of isradipine under fasted and fed conditions

From measurements of drug levels in both gastric juice and plasma, we investigated whether or not a prolonged gastric residence time (GRT) is responsible for the slow absorption kinetics of a "floating" modified-release (MR) capsule of isradipine [isopropyl methyl (+/-)-4-(4-benzofurazanyl)-1,4-dihydro-2,6-dimethyl-3,5- pyridinedicarboxylate], a lipophilic dihydropyridine calcium channel blocker. The effects of a "high-fat" breakfast on the intragastric behavior and absorption kinetics were also assessed. In an open crossover design, five healthy subjects ingested either a normal or MR capsule of isradipine under fasted conditions. Serial samples of gastric juice (obtained via an indwelling nasogastric tube) and plasma were collected up to 24 h after drug intake, and were analyzed for isradipine by GC and RIA methods, respectively. The pH and titratable acid, protein, and pepsin concentrations of the gastric juice samples were also determined. Four additional subjects were similarly studied after ingesting the capsules following a high-fat breakfast. Under fasted conditions, gastric juice drug levels of the normal and MR capsules indicated a median GRT of less than 1.5 h in both cases. Plasma levels indicated a rapid absorption for the normal capsule (less than 2 h), but a remarkably slow absorption for the MR capsule, lasting 24 h or more. Under fed conditions, gastric juice and plasma profiles of the normal capsule were similar to those for the fasted case. In contrast, the MR capsule had an increased GRT (approximately 2.4 to 4.8 h) that was associated with a delayed and more extensive intragastric drug release. The corresponding plasma profiles showed a rapid absorption phase which correlated closely with the intragastric release kinetics. The influence of a high-fat meal on the release kinetics of the MR capsule did not appear related to the intragastric pH, or acid, protein, or pepsin concentrations. From these results we conclude that: (1) a prolonged GRT is not responsible for the slow absorption achieved with a "floating" MR capsule; (2) the presence or absence of food, rather than buoyancy, is the principal determinant of the GRT of the MR capsule; (3) the release and absorption of a lipophilic drug from a "floating" MR capsule may be affected by intragastric interaction with the lipid phase of meal; and (4) the major portion of drug release from the MR capsule takes place in the colon, rather than in the stomach.

Effect of a slow-release formula of trimoprostil on intragastric acidity in healthy volunteers

We investigated the effect of a slow-release formula of trimoprostil, a prostaglandin E2 analogue, at a dose of 3 mg b.d. on circadian intragastric acidity in nine healthy volunteers using ambulatory pH-metry in a placebo-controlled study. The effect of trimoprostil was long lasting (8 hours during the night). However, it lowered gastric pH on average only by 0.4 pH units. In four of the six women severe side-effects occurred in the form of abdominal cramping, metrorrhagia, and/or diarrhoea. These disadvantages may limit the clinical use of this drug.

Microsphere estimates of blood flow: methodological considerations

The microsphere technique is a standard method for measuring blood flow in experimental animals. Sporadic reports have appeared outlining the limitations of this method. In this study we have systematically assessed the effect of blood withdrawals for reference sampling, microsphere numbers, and anesthesia on blood flow estimates using radioactive microspheres in dogs. Experiments were performed on 18 conscious and 12 anesthetized dogs. Four blood flow estimates were performed over 120 min using 1 X 10(6) microspheres (15 microns) each time. The effects of excessive numbers of microspheres (13 million), pentobarbital sodium anesthesia (30 mg/kg), and replacement of volume loss for reference samples with dextran 70 were assessed. In both conscious and anesthetized dogs a progressive decrease in gastric mucosal blood flow and cardiac output was observed over 120 min. This was also observed in the pancreas in conscious dogs. The major factor responsible for these changes was the volume loss due to reference sample withdrawals. Replacement of the withdrawn blood with dextran 70 led to stable blood flows to all organs. The injection of excessive numbers of microspheres did not modify hemodynamics to a greater extent than did the injection of 4 million microspheres. Anesthesia exerted no influence on blood flow other than raising coronary flow. We conclude that although blood flow to the gastric mucosa and the pancreas is sensitive to the minor hemodynamic changes associated with the microsphere technique, replacement of volume loss for reference samples ensures stable blood flow to all organs over a 120-min period.

Does smoking interfere with the effect of histamine H2-receptor antagonists on intragastric acidity in man?

The interaction between smoking and the effect of histamine H2-antagonists on intragastric acidity was examined in a double blind double dummy placebo controlled study. Healthy volunteers, 11 smokers and 10 non-smokers, were given, on four separate days at least one week apart, either placebo or cimetidine 800 mg nocte or ranitidine 2 X 150 mg per day or ranitidine 300 mg nocte. Tablets were taken at 2115 and 0900 h. Smokers smoked a cigarette hourly from 0700 to 2300 h. Breakfast, lunch, and dinner were standardised. Intragastric acidity was measured with a combined intragastric glass electrode and a solid state recorder. The subjects were fully ambulatory. The three histamine H2-receptor antagonist regimens were less effective (p = 0.04) in smokers than in non-smokers, but the difference between acidity of smokers and non-smokers was small. Means of medians of pH during a 24-h period with placebo, cimetidine 800 mg, ranitidine 2 X 150 mg and ranitidine 300 mg were 1.6, 2.3, 3.1, and 2.7 in smokers and 1.5, 2.7, 3.2, and 3.1 in non-smokers, respectively. In a second part of the study seven chronic smokers were reexamined after acutely stopping smoking: inhibition of gastric acidity by histamine H2-receptor antagonists was similar before and after withdrawal. Smoking does not affect intragastric acidity in untreated volunteers and only slightly decreases the effectiveness of histamine H2-receptor antagonists on intragastric acidity. This effect best in part explains the unfavourable effect of smoking on healing of peptic ulcer in patients treated with these drugs.

Reduction of gastric acidity with ranitidine or famotidine: early evening dosage is more effective than late evening dosage

The antisecretory effect of a once daily dose of ranitidine and famotidine was examined after administration of the drugs either immediately after dinner or 3 h after dinner. A placebo-controlled multiple cross-over study was performed in 7 healthy ambulatory volunteers. They were given, on 6 separate days at least 1 week apart, either placebo, ranitidine 300 mg or famotidine 40 mg, either immediately after dinner or 3 h later. Breakfast, lunch and dinner were standardized. 24-Hour intragastric acidity was measured with a combined glass electrode. Duration of secretory inhibition by a drug was defined as the nighttime period between the first rise of pH above and the final fall below 3.5. This value represents the 95% upper confidence limit of nighttime pH values during placebo treatment. Secretory inhibition with early and late administration of ranitidine lasted for 10.7 and 7.3 h, respectively (p = 0.012). With famotidine it lasted for 10.1 and 7.1 h, respectively (p = 0.005). Gastric acidity after dinner was decreased by early but not late intake of ranitidine and famotidine. Thus, both ranitidine and famotidine were more effective when taken early, immediately after dinner, than when taken late in the evening. This observation might affect the mode of ulcer treatment with these drugs.

Is there a relationship between gastric mucosal blood flow and stress lesions in hemorrhagic shock?

The relationship between gastric mucosal blood flow and stress lesion formation during hemorrhagic shock was studied in anesthetized dogs. Shock was induced by graded arterial bleeding. Blood flow was measured by means of the radioactive microsphere technique. Mapping of blood flow was achieved by measuring the microsphere accumulation in mucosal and muscle segments of 1-2 cm side length of the entire stomach. To produce a varying incidence of lesions the metabolic acidosis of shock was either fully corrected by intravenous sodium bicarbonate (n = 5), partially corrected (n = 4) or left uncorrected (n = 3). Mucosal lesions developed more frequently in dogs without correction than in dogs with partial correction or full correction. In 4 dogs not subjected to shock, no mucosal lesions were observed at the end of the experiments. Mucosal blood flow varied from segment to segment by a factor of up to 20, but individual segments tended to maintain their relative flow values during shock. Correction of metabolic acidosis did not significantly affect blood flow. Likewise, flow was similar in segments with and without lesions. Therefore, low regional blood flow did not predispose to the development of lesions and high flow did not prevent them. We conclude that focal mucosal ischemia alone does not lead to stress lesion formation during hemorrhagic shock.

It is wise to prescribe NSAIDs with modern gastroprotective agents?

The administration of non-steroidal anti-inflammatory drugs (NSAIDs) leads to mucosal lesions in the upper gastrointestinal tract. Furthermore, NSAIDs increase the risk of ulcer bleeding and perforation, but the overall risk of fatal complications is relatively small (about 21 per one million prescriptions). Therefore, in asymptomatic patients, it is not justified to prescribe NSAIDs together with gastroprotective agents. The following recommendations can be given with respect to the management of peptic lesions in patients taking NSAIDs: (i) Fibre endoscopy should be performed even when there are relatively mild symptoms since mucosal lesions in rheumatic patients under NSAIDs produce minor or no symptoms. (ii) "Modern" NSAIDs might produce less gastric lesions than aspirin. (iii) Rheumatic patients with peptic disorders should be treated with an H2-antagonist. (iv) After complications such as ulcer bleeding or after rapid recurrence of peptic lesions, maintenance treatment with an H2-antagonist is advisable.

Endoscopy as final arbiter in controlled clinical trials in peptic disorders

Endoscopy should not be the sole final arbiter in controlled clinical trials of peptic disorders. Data on the response of symptoms to treatment and the occurrence of side-effects may be not as 'hard' as endoscopically assessed 'healing' and 'relapse', but may be clinically more meaningful. Furthermore, in most recent trials, 'healing' and 'relapse' were poorly defined; important information on residual mucosal lesions after healing was often neglected.

Clinical perspectives of drugs inhibiting acid secretion: histamine H2 antagonists

The present report shows that the following statement is correct: 'Uncomplicated peptic ulcer is best treated with a strongly acting histamine antagonist given once daily with dinner for 4 weeks and by abstention from smoking'.