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Biomedical subjects

F Halter

Publications and source records attributed to F Halter.

At least 91 records · Page 5Linked to original sources
PubMed1983

Mechanism of action of cholecystokinin octapeptide on rat antrum, pylorus, and duodenum.

The mechanism of action of cholecystokinin octapeptide (CCK-OP) on tonic and phasic contraction of antral, pyloric, and duodenal smooth muscles was studied with a novel perfusion manometric system in isolated esophagogastroduodenal preparations of the rat. CCK-OP increased baseline pressure at each site, frequencies of phasic contractions in the antrum and pylorus, and amplitudes in the duodenum. It decreased antral and pyloric amplitudes and frequency of duodenal phasic contractions. CCK-OP action on tonic contraction was tetradotoxin (TTX) susceptible and its action on phasic contractions was TTX resistant. Phentolamine, phenoxybenzamine, propranolol, catecholamine depletion of preparations by reserpine-tetrabenazine, and the block of catecholamine synthesis at different levels significantly inhibited CCK-OP-induced tonic contraction, whereas atropine had no influence. Adrenergic and cholinergic neural actions on phasic contractions altered the level of amplitudes and frequencies on which CCK-OP action occurred. It is concluded that CCK-OP action on tonic contraction of the rat gastroduodenal junction is mediated by a neural noncholinergic pathway, whereas its effect on muscles responsible for phasic contractions is a direct one.

Animals↗
PubMed1983

Comparison of gastrointestinal loss of alpha-1-antitrypsin and chromium-51-albumin in Ménétrier's disease and the influence of ranitidine.

In a 37-year-old patient with Ménétrier's disease, 51Cr-albumin and alpha 1-antitrypsin (alpha 1-AT) output was measured simultaneously in gastric juice and feces. While the 51Cr-albumin studies demonstrated a threefold increase in gastrointestinal protein loss, alpha 1-AT was found in normal quantities in gastric juice and feces. The histamine H2 antagonist, ranitidine, led to a marked reduction in gastric protein loss, as evidenced by decreased 51Cr activity in the stomach. Studies of protein loss in the gastric juice during pentagastrin stimulation (6 micrograms/kg/h) showed that the 51Cr-albumin output paralleled the volume secreted, whereas alpha 1-AT decreased with lower pH values, not being detectable below pH 3. This probably results from peptic degradation of alpha 1-AT at low pH. We conclude that fecal alpha 1-AT determination cannot be used for the assessment of protein-losing gastropathy in patients who are not achlorhydric.

Adult↗
PubMed1983

Influence of long-term 16,16-dimethyl prostaglandin E2 treatment on the rat gastrointestinal mucosa.

We performed acid secretory and histomorphometric studies in rats treated intragastrically with a regimen of 100 micrograms/kg or 5 micrograms/kg of 16,16-dimethyl prostaglandin E2, or of saline every 8 h for 21 days. All animals given the high-dose treatment developed a macroscopically visible enlargement of the ridge at the corpus-forestomach border, due to an increase in connective tissue and epithelial cell layer. Mucosal thickness was significantly increased in all parts of the stomach, the duodenum, and the proximal colon, but most markedly in the gastric antrum (+115%), where it was accompanied by a higher mitotic rate and hyperplasia of surface and foveolar mucous cells. Within the oxyntic area (corpus), high-dose prostaglandin treatment led to an increase in the number of surface and foveolar mucous cells and chief cells. In contrast, both the number of parietal cells and maximal acid output were not influenced. It is unlikely that the hyperplasia of gastric mucosa is mediated by gastrin since gastrin has no trophic effects on the rat antrum and disproportionally increases the parietal cell number of the oxyntic gastric glands.

16,16-Dimethylprostaglandin E2↗
PubMed1983

[Determination of neutralization capacity of antacids in gastric juice].

Observations made during intragastric titration studies performed with antacids that have an identical neutralizing capacity but differ in their chemical compositions suggested that aluminum hydroxide loses a large portion of its neutralizing capacity when applied postprandially. To further elucidate the mechanism involved in-vitro studies were performed whereby the reactivity of magnesium hydroxide, aluminum hydroxide, and calcium carbonate was estimated either in aliquots of 10 ml of water or 10 ml of 5% oxo solution. The effectively available neutralizing capacity of the respective antacids was measured for the pH range of 1 to 5. The results revealed that magnesium hydroxide as well as calcium carbonate can fully react with acid whereby their theoretically available neutralizing capacity is fully available for the pH of 1 to 4.5, this in water as well as in 5% oxo solution. In contrast, aluminum hydroxide loses a large proportion of the theoretically available neutralizing capacity already in water but especially in oxo solution in a pH dependent manner. The loss far exceeds that calculated when one takes into account the pKa dependent hydrolysis of aluminum hydroxide. This loss of reactivity increased from 20% at pH 1 in a near linear fashion up to above 80% at pH 3.5. A food induced decrease of aluminum hydroxide solubility as well as stabilisation of the macromolecular aluminum hydroxide complexes through anions and organic acids are likely to be responsible for this loss of reactivity.

Aluminum Hydroxide↗
PubMed1982

[Treatment of reflux esophagitis with ranitidine. A multicentric prospective study].

Thirty-eight patients with erosive-ulcerative reflux esophagitis were treated in an open trial with the histamine-H2-receptor antagonist ranitidine (150 mg twice daily). At endoscopy after 6 weeks there was evidence of complete healing of all epithelial defects in 20 of 38 patients (53%). Continuation of treatment for another 6 weeks in 13 patients was followed by healing in 6 additional patients as judged by endoscopy. Although the symptoms of the group as a whole improved significantly during treatment, there was no correlation between the degree of symptomatic improvement and healing of esophagitis. Also, the healing rate did not depend on age, sex, smoking and drinking habits or on the severity of esophagitis. It is concluded that medical treatment of reflux esophagitis with ranitidine is promising, even in severe cases previously considered candidates for surgery.

Anti-Ulcer Agents↗
PubMed1982

Effect of food on antacid neutralizing capacity in man.

In order to estimate their in-vivo reactivity two antacids of equal theoretical neutralizing capacity (approximately 3.9 mol/l at pH 3.5) but of different chemical composition were employed as intragastric titrant (pH 3.5) following a liquid protein meal (oxo) in two groups of five volunteers each. The two antacids chosen (alucol and Camalox) contain different amounts of aluminium hydroxide, magnesium hydroxide and Camalox in addition contains calcium carbonate. The intragastric consumption of these two antacids was much higher than their respective theoretically available neutralizing capacity (Alucol 3.9 times, Camalox 2.4 times). In-vitro studies demonstrated that interaction with oxo reduced the neutralizing capacity of the two antacids at pH 3.5 from 3.9 mol/l to 1.7 mol/l (Alucol) and 2.5 mol/l (Camalox). This potency loss was related to the aluminium hydroxide content of the two antacids. This study indicates that the neutralizing capacity of antacids is not predictable from their reactivity in aqueous solution and is markedly reduced by protein-containing foods.

Adult↗
PubMed1982

Sensitivity of the parietal cell to pentagastrin in health and duodenal ulcer disease: a reappraisal.

In view of the conflicting results on whether pentagastrin sensitivity is genuinely increased in duodenal ulcer (DU) patients, the pentagastrin-gastric acid relationship was restudied in 17 normal subjects and 15 DU patients. In a reproducibility study performed on nine healthy subjects the mean pentagastrin responses obtained on 2 different study days, using a step technique (range, 0.025-6.4 micrograms kg-1h-1), were congruent at each of the five measuring points. Analysis of variance revealed no significant overall differences. However, ED50 values showed a large within- and between-subject variation and failed to correlate significantly, this because a plateau response was not regularly obtained with the top dose. Consequently, ED50 values in normal subjects and DU patients showed a large scatter and were not significantly different, although the potency ratio calculated from the linear parts of the respective dose-response curves was significantly different (2.6; 95% confidence limits, 1.8-3.9). This study thus supplies further evidence that the parietal cell of DU patients has a higher sensitivity to pentagastrin and demonstrates that the reliability of individual ED50 estimations obtained in pentagastrin dose-response studied should not be overrated.

Adult↗
PubMed1981

[Differential diagnosis of ulcerative colitis].

The confusion arising from the misnomer "ulcerative colitis" when used to characterize idiopathic hemorrhagic proctocolitis is emphasized, and an attempt is made in this postgraduate lecture to classify inflammatory bowel disease by subdivision into hemorrhagic and non-hemorrhagic forms. The limits of such didactic simplifications are stressed and special attention is focused on little-known conditions such as " diversion colitis" and Campylobacter colitis.

Colitis, Ulcerative↗
PubMed1981

[The effect of salmon calcitonin on pancreatic enzymes and hormones before and after retrograde cholangiopancreatography].

The effect of salmon calcitonin (SMC) on pancreatic enzymes and hormones was investigated following retrograde choledocho-pancreatography (ERCP). 40 patients were randomly divided in two groups and 2.5 micrograms/h SMC or sodium chloride was infused intravenously for 28 hours. Infusion was started 4 hours before endoscopic procedure and amylase, lipase, glucose, insulin, glucagon and gastrin plasma concentrations were measured before and 2, 12 and 24 hours after the end of the ERCP. According to the radiological findings of pancreatography two additional groups were formed: group 1 with visualization of the main duct and its branches and group 2 with additional visualization of the pancreatic parenchyma. No change in glucose, insulin, glucagon and gastrin was found in any of the groups analyzed. Amylase and lipase showed a significant increase after 2 hours and 24 hours later, values were reached which were not significantly different to baseline levels. The time course of the plasma concentrations was identical in the patients treated by SMC or sodium chloride and showed no significant difference at the various time intervals. Therefore, inhibition of the known increase in pancreatic enzymes following ERCP was not found with SMC treatment.

Amylases↗
PubMed1981

[New aspects in the treatment of cholecysto-and choledolithiasis].

Since gallstone disease is one of the most frequent gastrointestinal disorders (average incidence 27% in males and 47% in females) it is mandatory for practicing physicians to keep abreast of recent progress in therapy. Thus, present treatment is based on the radiologic pattern of radiolucent (cholesterol) and radioopaque (calcium containing) stones. In the young patient, cholecystectomy is recommended for cholecystolithiasis regardless of type of stones, because this procedure is likely in most cases to provide optimal, definitive results at minimal risk. In the elderly, or when the operative risk is aggravated by accompanying disease, an attempt may be made to dissolve cholesterol stones by oral administration of cheno- or ursodeoxycholic acid. Following 18 months to 2 years of medication, the success rate for complete dissolution is approximately 50%.

Aged↗
PubMed1981

Estimation of the biliary excretion of different cephalosporins utilizing retrograde cholangio-pancreatography (ERCP).

In the present study 21 patients undergoing retrograde cholangio-pancreatography (ERCP) were given cefamandole, cefazolin or cefaclor, and plasma and bile concentrations were measured. The cannulation of the common bile duct was possible in most of the patients investigated, but no bile could be obtained in 7 of them. In the patients in whom bile was obtained, concentrations comparable to other studies were estimated, despite a wide variation in the individual patients. In addition, cefaclor, which is not known to be excreted in the bile, showed sufficiently high inhibitory bile concentrations. Using ERCP for the estimation of bile concentrations of different drugs useful information can be obtained about the excretion of certain substances. However, for sophisticated pharmacokinetic studies, the method has certain limitations as compared with classical T-tube sampling.

Adult↗