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Biomedical subjects

H Ruppin

Publications and source records attributed to H Ruppin.

At least 55 records · Page 3Linked to original sources
PubMed1983

[Gastric microhemorrhage and acetylsalicylic acid. Prevention using prostaglandin E2].

The possible prophylactic effect of prostaglandin E2 (PGE2) pretreatment against gastric microbleedings caused by acetylsalicylic acid was investigated in six healthy volunteers. Gastric microbleeding rate was determined by the gastric tube technique of Fisher and Hunt, at first without any medication. The test was repeated after a two-day intake of acetylsalicylic acid (four times 0.5 g/d) and after two days of the same dose, 15 minutes after the administration of PGE2 (four times 0.5 mg/d). Between the two treatment periods, their sequence randomized, there was a treatment-free pause of at least eight days. Basic gastric microbleeding rate was 0.42 +/- 0.10 ml/d (means +/- Smeans). After administration of acetylsalicylic acid this rose highly significantly elevenfold (4.59 +/- 1.64 ml/d). Prophylactic administration of PGE2 prevented this rise (0.24; 0.04-2.55 ml/d) (median; 10th-90th percentile). There were no side effects to the administration of PGE2.

Adolescent↗
PubMed1983

Measurement of gut hormonal peptides in biopsies from human stomach and proximal small intestine.

Using sensitive and specific radioimmunoassays, concentrations of hormonal peptides have been measured in small biopsies taken from the human stomach, duodenum, and proximal jejunum. Comparison is made of these hormone concentrations and the number of respective endocrine cells present determined by quantitative immunocytochemistry. Immunoreactive somatostatin, VIP, motilin, and gastrin were detected in all regions examined, whereas secretin and GIP were undetectable in antral extracts. Enteroglucagon-like immunoreactivity was present only at and beyond the ligament of Treitz, although a few enteroglucagon-producing cells were shown by immunocytochemistry in the duodenum. The variation of hormone concentration was found to be small in these biopsies of normal tissue within each region of the gut examined, indicating that representative hormone concentrations may be reliably obtained from small biopsy tissues. An attempt has been made to establish reference values for gut hormone concentrations in such biopsies; this may allow future study of any changes in concentration that may occur in pathological conditions.

Adult↗
PubMed1983

[Endogenous synthesis of carcinogenic N-nitroso compounds: bacterial flora and nitrite formation in the healthy human stomach].

The endogenous synthesis of cancerogenic N-nitroso compounds: Bacterial flora and nitrite formation in the human stomach. In the discussion of the endogenous nitrosamine synthesis, nitrites play a decisive role. Since in a healthy stomach the acidity important for the nitrosamine formation is present, but since this acid environment is hostile to the bacterial growth and thus counteracts bacterial endogenous nitrite formation, the oral cavity has so far been regarded as the main site of endogenous nitrite formation. An analysis of 130 gastric secretions taken from empty stomachs has demonstrated that also in a healthy stomach considerable germ counts may be obtained in part when acidity is lowered physiologically (e.g. at night). Nitrite concentrations, which are six times as high as the quantities supplied with the saliva at the same time, are also produced in the acid pH range from 4 to 6. Consequently, in a healthy stomach as well the quantity of nitrite available for an endogenous nitrosamine synthesis is by far higher than has been assumed previously. This physiological risk should be allowed for in evaluating the pathophysiological or therapeutic changes in the gastric environment.

Bacteria↗
PubMed1983

[Intragastric utilization of antacids following meals in relation to stomach emptying].

Gastric acid secretion and gastric emptying rate was measured using double marker method and continuous titration of a liquid peptone test meal. Titration rate was significantly reduced by 30 ml of an aluminiumhydroxide- and magnesiumhydroxide containing antacid compound (Maalox). Acidity of gastric contents was reduced over a period of 48.4 +/- 9.1 min (mean +/- SD; endpoint of titration pH 5.5) and 77.6 +/- 2.0 min (pH 3.5) (p less than 0.05). The histamine H2-receptor blocker Ranitidine (0.25 mg/kg b.w.) and the antimuscarinic agent Pirenzepine reduced titrable gastric acid secretion in a similar range, as far as the observation period of 90 min is concerned. Biosorbin MCT, a formula diet, stimulated gastric acid secretion half the amount of gastric acid secretion stimulated by the peptone meal. Gastric emptying rate was significantly reduced by formula diet, but not by either of the other compounds.

Adult↗
PubMed1982

Gastric cytoprotection by antacids and papaverine in rats.

Prostaglandin E2 (PGE2) prevented hemorrhagic ulceration of rat stomach mucosa induced by various procedures when given orally at a non-antisecretory dose. This effect of PGE2 is called gastric cytoprotection. We used absolute ethanol, 0.6 N hydrochloric acid and 0.2 N sodium hydroxide as damaging agents. Ranitidine at an antisecretory dose did not exhibit any cytoprotective effect. However, the poorly absorbable antacids, magnesium hydroxide plus aluminium hydroxide and aluminium phosphate inhibited the development of hemorrhagic lesions significantly. A similar protective effect was seen after intragastric administration of papaverine, which is known to stimulate endogenous prostaglandin synthesis. However, the question as to whether or not stimulation of endogenous prostaglandin synthesis is the mode of action of the cytoprotective effect of papaverine and poorly absorbable antacids, cannot yet be answered.

Aluminum Compounds↗
PubMed1981

Effects of liquid formula diets on proximal gastrointestinal function.

Upper gastrointestinal function in response to liquid test meals of varying osmolality (337, 519, and 696 mosmol/kg) was studied in volunteers. The osmolality was varied by changing the carbohydrate component from a glucose polymer (Polycose) to sucrose. During the first hour, the least hypertonic meal was emptied most rapidly, leading to the highest rate of nutrient delivery to the duodenum. Most carbohydrate was hydrolyzed and absorbed (65-82%) in the duodenum. Higher flow rate and carbohydrate load at the ligament of Treitz soon after administering the Polycose meal had to be compensated by increased water and monosaccharide absorption in the first 30 cm of jejunum. Thus, at a point 30 cm into the jejunum, there were no significant differences in the flow and composition of chyme; all but about 10% of the carbohydrate load was absorbed; and the flow rate was no higher than after an ordinary meal.

Adult↗
PubMed1981

Human intestinal potential difference: recording method and biophysical implications.

1. The transmural electrical potential difference (PD) of the intact human small intestine was recorded with close attention to electrical symmetry, shielding from electro-magnetic waves and correction for junction potentials. 2. The PD is -12 mV (mucosa-negative) in the fasting jejunum and ileum and does not change during perfusion with isotonic NaCl. 3. Absorption of Na and Cl appears to be non-electrogenic and the 'resting' PD is probably generated by active anion secretion of fasting intestinal contents. 4. Diffusion potentials during isotonic D-mannitol perfusion indicated higher cation selectivity in the ileum than in the jejunum. 5. The calculated contribution of a free-solution path to total paracellular permeability is 55% in the jejunum but only 15% in the ileum. 6. No 'streaming' potential was detected during osmotic water flow, suggesting that the cation-selectivity of the channels is temporarily inactivated during dilatation of the lateral intercellular space.

Adult↗
PubMed1981

Gastric cytoprotection in man by prostaglandin E2.

In healthy volunteers, the effects of topical prostaglandins E2 (PGE2), 1 mg, on transmucosal potential difference (PD), mucus secretion, and epithelial cell turnover were investigated. PGE2 increased gastric PD by 10 mV on an average and stimulated mucus secretion of the stomach by 50%. In contrast, epithelial cell turnover remained unchanged. Gastric output of H+ decreased, whereas the outputs of volume, Na+, and Cl- rose in response to PGE2, which effects would be compatible with increased secretion of bicarbonate. Topical administration of ethanol 40% (vol/vol) reduced PD by 25 mV (delta PDE) and enhanced epithelial cell shedding by 350% with concomitant discharge of mucus from stomach epithelium. Pretreatment of the stomach with 1 mg PGE2 prevented the ethanol-dependent epithelial cell exfoliation, indicating gastric mucosal cytoprotection. Delta PDE and discharge of mucus were not significantly altered by PGE2. We conclude that gastric cytoprotection by PGE2 in man might be mediated by stimulation of mucus and/or bicarbonate production.

Adult↗
PubMed1980

Absorption of short-chain fatty acids by the colon.

Short-chain fatty acids (SCFAs) constitute the major solute fraction of normal stool water and are responsible for the diarrhea associated with carbohydrate (CHO) malabsorption. Although SCFA absorption from the human small bowel has been reported previously, the fate of SCFAs in the colon--their major site of production--was investigated in the present study. The colon of normal volunteers was perfused with neutral, isotonic solutions containing SCFA, 0-90 mM. Propionate was studied in detail with limited observations on acetate and n-butyrate. SCFA absorption was concentration-dependent; back diffusion of metabolic products, ketone bodies, was quantitatively insignificant. The transport process was accompanied by increased Na, K, and water absorption, by luminal alkalinization due to bicarbonate accumulation, and by a fall in lumen PCO2. The results are consistent with the existence of two mechanisms for colonic SCFA absorption: first, nonionic diffusion of protonated SCFA involving consumption of luminal CO2; this process accounts for about 60% of total SCFA absorption; and second, cellular uptake by ionic diffusion of the Na or K salt of the SCFA.

Adult↗
PubMed1977

[Therapy of peptic ulcer and chronic pancreatitis].

Medical treatment of gastric and duodenal ulcerations has recently been improved and extended by anti-aggressive and protectively acting drugs (e.g., H2-receptor antagonists and carbenoxolone sodium). However, antacids and anticholinergic treatment are still being used in modern ulcer management. The most important therapeutical measures against chronic relapsing pancreatitis are abstinence from ethanol and surgical treatment of biliary or pancreatic duct obstructions. Symptomatic management--pancreatic enzyme substitution and analgetics, antacids, anticholinergics--is adequate in pancreatic insufficiency and during acute exacerbation, respectively.

Antacids↗
PubMed1977

The gastrointestinal myoelectric response to 13-Nle-motilin infusion during interdigestive and digestive states in the conscious dog.

Gastrointestinal myoelectric activity was studied in three conscious fasted dogs with electrodes surgically implanted in the stomach and small intestine, during separate and combined intravenous infusions of 13-norleucine motilin (13-nle-motilin) and pentagastrin (PG). Basal recordings confirmed the presence of regular interdigestive myoelectric complexes (MC's). 13-nle-motilin infusion below 50 ng/kg-h was without effect: higher doses up to 400 ng/kg-h resulted in the interpolation of one or more MC's in the spontaneous sequence. The rate of aboral transit of 13-nle-molitin-induced MC's did not differ significantly from that of spontaneous MC's. When MC's were abolished by feeding or PG infusion, simultaneous 13-nle-motilin administration was without effect on spike activity, but slightly attenuated the accelerating effect of gastrin on the gastric pacemaker frequency. The myoelectric events triggered by 13-nle-motilin suggest that in the conscious dog the polypeptide may not act directly on the smooth muscle cell, as it does in vitro, but through an extra-enteric neural control mechanism which is uncoupled by gastrin.

Aminocaproates↗