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Biomedical subjects

P Bauerfeind

Publications and source records attributed to P Bauerfeind.

At least 91 records · Page 5Linked to original sources
PubMed1989

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.

Animals↗
PubMed1989

[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.

Carcinoembryonic Antigen↗
PubMed1989

[Screening for colorectal tumors using fecal occult blood studies].

Guaiac tests such as Hemoccult are widely used but are affected by several factors. Occult blood testing does uncover subclinical colorectal cancer often at early stage, but a favorable effect on survival remains to be proven. The sensitivity for the detection of malignancies is from moderate to good, but it is poor for benign polyps. Predictive value of a positive test for cancer ist about 8-12%. Thus, most of the individuals with a positive test would not need colonic investigations. Recommendations relating to the testing for of occult blood could change rapidly with the new immunologic techniques or with new data on mortality coming from controlled clinical trial now being conducted.

Colorectal Neoplasms↗
PubMed1989

Direct cytotoxic effect of oxygen radicals on the gastric mucosa.

Oxygen radical release has been proposed as a pathogenetic factor in the formation of acute gastric mucosal injury. We assessed the ability of the naturally occurring oxygen radical generating system hypoxanthine/xanthine oxidase (HX/XO) to cause gross gastric mucosal injury and measured the effect on regional mucosal blood flow. Local intra-arterial infusion of HX/XO into the vascular network of the stomach caused marked gross mucosal injury in the antrum and corpus. This injury occurred even in the absence of exogenous luminal acid and was aggravated by luminal acidification with 1 ml of 0.1N HCl. The selective oxygen radical scavenger superoxide dismutase (SOD) prevented mucosal injury caused by HX/XO. The effects of HX/XO and SOD were not mediated by alterations in regional gastric mucosal blood flow, as measured by the radiolabeled microspheres and reference sample method. These findings suggest that oxygen radicals are capable of causing substantial gastric mucosal injury by a direct cytotoxic effect independent of luminal acid or mucosal blood supply and give support to the concept that oxygen radical release may be a major primary pathogenetic factor in the development of acute gastric mucosal injury.

Animals↗
PubMed1988

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.

Adult↗
PubMed1988

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.

Adult↗
PubMed1988

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.

Animals↗
PubMed1988

Diagnostic tests of gastric disorders.

In diagnostic of gastric diseases, fiberendoscopy is today the best procedure. It is superior to radiology with respect to the evaluation of mucosal lesions, the possibility of taking biopsy and therapeutic interventions like hemostatic procedures. Costs for endoscopy are not higher than for radiology. Endoscopy may have a certain morbidity - possible infections via the endoscope - and a mortality less than one per 10.000. Radiology is still useful with respect to the evaluation of motility, the type, form and size of hernias, the presence of extrinsic lesions and certain problems after surgical interventions such as fundoplication. For determination of gastric secretion, the 24-hour ambulatory gastric pH-metry using endoluminal glass electrodes is much more useful than the tests of gastric aspiration. Gastric emptying test and measurement of duodenogastric reflux play a relatively small role in clinical evaluations.

Campylobacter Infections↗
PubMed1987

Lessons from prolonged gastric pH monitoring.

Intragastric pH monitoring has shown that the distribution of acidity within the stomach is not homogeneous. Not only is it affected by meals but it also has a circadian rhythm in which nocturnal pH falls to very acid levels in normal subjects. Although results of pH monitoring are highly reproducible within individuals, considerable inter-individual variation has been shown. Duodenal ulcer patients do not appear to possess the normal buffering reaction to meals, but their night-time acidity is within the normal range. In these patients, antacids and pirenzepine have a small acid-neutralizing effect in the stomach; cimetidine is less potent than ranitidine and famotidine. Clinicians can choose between a single dose of either ranitidine or famotidine in the evening with dinner and a twice-daily regimen.

Gastric Acid↗
PubMed1987

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.

Adult↗
PubMed1987

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.

Adult↗
PubMed1987

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.

Animals↗
PubMed1987

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.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1986

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 Trials as Topic↗
PubMed1985

[Continuous intragastric pH-metry].

Ambulatory intragastric pH-metry is a suitable method of assessing gastric acidity under conditions of normal daily life. A detailed profile of intragastric acidity is given which is a reproducible individual characteristic. There is a circadian rhythm of gastric acidity in which pH rises during the night and after meals. pH-metry was used to determine the effects of H2-antagonists and antacids, and the results are the basis for the clinical use of intragastric pH-metry.

Antacids↗