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Effect of gastric hypersecretion on the canine duodenum.

The neutralization of acid introduced into the duodenum has been found to be less intensive in patients with duodenal ulcer than in controls. The present work studied the possibility that chronic gastric hypersecretion injures the duodenal mucosa and thereby influences the neutralization system. Gastric hypersecretion was provoked for 3 weeks in 3 dogs by a daily injection of a gastrin preparation with prolonged effect. After a subcutaneous injection of this preparation given together with a test meal the acidity of both gastric and duodenal contents was found to increase significantly. After the 3 weeks of gastric hypersecretion the pancreatic bicarbonate response to exogenous secretin was unchanged, while the bicarbonate response to duodenal acidification was decreased from 2.03 mEq/30 min to 1.27 mEq/30 min (p less than 0.05), compatible with an impaired secretin release. Also the concentration of lactase, maltase, sucrase, and alkaline phosphatase in mucosal biopsies from the second part of the duodenum was significantly reduced (p less than 0.001). These results indicate that gastric hypersecretion causes mucosal damage in the duodenum and thereby reduces the release of secretin.

Alkaline Phosphatase

Comparison of an H2 receptor antagonist and a neutralizing antacid on postprandial acid delivery into the duodenum in patients with duodenal ulcer.

Measurement of the postprandial rate of acid delivery into the duodenum directly assessed the efficacy of two radically different acid-reducing therapies for duodenal ulcer disease. Cimetidine, 400 mg, with an ordinary solid meal decreased the 4-hr delivery of titratable acid and hydrogen ion into the duodenum by 63 and 86%, respectively (P less than 0.01 versus control). Liquid Maalox, 30 ml, 1 and 3 hr after an identical meal reduced 4-hr delivery of acid by 47 and 74%, respectively (P less than 0.01 versus control). During the study period, the H2 receptor antagonist effected a continuous reduction in gastric acidity and the delivery of acid into the duodenum. The liquid neutralizing antacid produced a more fluctuating decrease in these parameters. However, given in these dosages, the magnitude and duration of the acid-reducing effect were similar for both treatments.

Aluminum Hydroxide

Effect of monopolar electrocoagulation on esophagus, stomach and duodenum in dogs.

The effects of electrocoagulation on the esophagus, stomach and duodenum of mongrel dogs were studied. A commercially available electrocoagulator unit and suction electrode were used. Various dial settings and duration times were used. The total number of sites electrocoagulated was 945; histologic section of each site was prepared. A dial setting of 7 and duration of 5 seconds was safe for the canine esophagus and duodenum; for the stomach it is a dial setting of 7 and duration of 3 seconds. This information will be useful in safe application of electrocoagulation to superficial bleeding lesions in the canine esophagus, stomach and duodenum.

Animals

The sites in the duodenum of receptor areas which affect abomasal emptying in the calf.

Calves were prepared with abomasal and duodenal cannulae to assess the effects on abomasal emptying of duodenal infusates at different rates and different sites. In two calves infusions of isotonic NaHCO3 or 60 mM HCl 30 cm distal to the pylorus were as effective in controlling abomasal emptying as infusions of the duodenum from 5 cm distal to the pylorus, and in three other calves they were as effective as perfusing the whole duodenum including the most proximal 5 cm. Reducing the rate of duodenal infusion of 60 mM HCl from 10 to 2.5 ml/min diminished its effect from total inhibition of gastric emptying to slight or negligible inhibition. The stimulation of gastric emptying by duodenal infusion of isotonic NaHCO3 solution was undiminished by reduced rates of infusion. It is proposed that in the calf receptors which activate and inhibit gastric emptying are present throughout the duodenum.

Abomasum

Primary adenocarcinoma of the duodenum.

Primary adenocarcinoma of the duodenum is rare. An extensive experience with fiberoptic esophagogastro-duodenoscopy in our institution has indicated that duodenal neoplasms may be more frequent than suspected and are readily diagnosed by this modality. With this mind, clinical, pathological, diagnostic and therapeutic aspects of the 71 patients with primary carcinoma of the duodenum reported in the literature in the last 10-year period, 1965-1974, were reviewed. It would appear that fiberoptic endoscopy of the upper gastro-intestinal tract should become the major diagnostic tool for this disease. It enables biopsies, brushings and washings to be taken. A preoperative histological diagnosis ensures that both patient and surgeon can be prepared for major abdominal surgery. It is imperatire that during the endoscopic examination, the entire duodenum be examined. Pancreatico-duodenectomy appears to offer the best chance of long term survival in patients whose lesion is resectable. The role and value of adjuvant chemo- and radiotherapy is still to be determined.

Adenocarcinoma

[Cyst of the duodenum with termination of the bile and pancreatic ducts (author's transl)].

The radiological findings in a 27-year old female Turkish patient with a cyst in the wall of the duodenum are described. It caused a sharply demarkated, smooth thumb-print in the duodenum shown by barium meal. An intravenous and intra-operative cholangiogram caused filling of the cyst with contrast through the bile duct. The bile and pancreatic ducts terminated on the medial side of the cyst through the papilla of Vater. The size of the cyst varied, depending on its degree of filling with bile and pancreatic juice. Its position and morphology has been confirmed at operation. Histology showed an external cover of small bowel mucosa and an inner lining of small bowel mucosa interspersed with islands of gastric mucosa. The development of this cyst is explained as a developmental anomaly during recalisation of the embryonic duodenum.

Adult

Fluid secretion in the duodenum and intestinal handling of water and electrolytes in Zollinger-Ellison syndrome.

The slow marker perfusion technique was used in five patients with the Zollinger-Ellison syndrome in order to determine the basal and postcibal flow rates of fluids passing the duodenojejunal junction and distal ileum, and the composition of those fluids. Fecal water and electrolyte excretions were also measured. The 24-hr outputs at the ligament of Treitz were markedly increased, while fecal losses were normal or only slightly increased. Thus, the overall intestinal reabsorption of water was 96%. Fasting rates of fluid and electrolyte flow at the ligament of Treitz were also measured during a basal period, followed by a period of continuous gastric aspiration. Removal of gastric secretion had the following effects on the fluid passing through the duodenum: (1) dramatic decrease in flow rate; (2) an increase in osmolality, from hypotonicity to isotonicity; (3) rise of pH, from acid to alkaline values; (4) a decrease of PCO2, from high to normal values. No increase in fasting plasma levels of immunoreactive secretin and motilin was observed in Zollinger-Ellison syndrome, whereas normal subjects respond to acid in the duodenum by a marked rise in the circulating levels of these hormones. These facts suggest that, in Zollinger-Ellison syndrome: (1) the ability of the small bowel and colon to reabsorb water and electrolytes is normal: (2) duodenal dissipation of hydrogen ions is mainly due to intraluminal neutralization by bicarbonate; and (3) stimulation of water and electrolyte secretion by the pancreas is inadequate.

Adult

Bradykinin action in the rat duodenum through the cyclic AMP system.

Activators of the adenylate cyclase or inhibitors of the cAMP-phosphodiesterase, respectively, potentiate the bradykinin-induced relaxation of the rat duodenum, whereas imidazole as a stimulator of the cAMP-phosphodiesterase reduces the relaxation. The experiments indicate a linkage between the adenylate cyclase system with the biological action of bradykinin on the rat duodenum. In contrast, no similar effect has been observed on the rat uterus.

3',5'-Cyclic-AMP Phosphodiesterases

Phosphate transport by embryonic chick duodenum. Stimulation by vitamin D3.

Embryonic chick duodenum maintained in organ culture is a well-suited model for the study of vitamin D effects on inorganic phosphate (Pi) absorption. The system is sensitive to as little as 6.5 nM vitamin D3 (0.1.I.U./ml culture medium). Increased phosphate absorption is observed after 6--12 h of culture. Maximal response (133% of vitamin D-efficient control) is achieved at 24 h. Phosphate uptake by embryonic chick duodenum involves a saturable and a non-saturable component. The former displays characteristics of an active sodium-dependent transport mechanism and is also sensitive to vitamin D3. Presence of the sterol in culture medium raises the maximal velocity from 55 to 75 nmol Pi/min per g tissue. Km remains unchanged (0.5 mM Pi). Duodena cultured in presence of inhibitors of protein synthesis (actinomycin D, alpha-amanitin and cycloheximide) display reduced rates of phosphate absorption. This treatment also prevents vitamin D3 action on phosphate transport. It is concluded that the sterol affects phosphate transport by modulation of synthesis of proteins which are functional in the Pi absorptive process.

Animals

A difference in effects of physiological Ca2+ concentrations on activity of guanylate cyclase preparations obtained from the taenia caecum of guinea pig and from the longitudinal muscle of rat duodenum.

A cholinergic stimulant, butyltrimethylammonium bromide and serotonin increased the tissue levels of cyclic GMP in the taenia caecum of guinea pig but not those in the longitudinal muscle of rat duodenum. On the other hand, physiological Ca2+ concentrations enhanced the activity of a guanylate cyclase preparation obtained from the taenia caecum of guinea pig, while guanylate cyclase in the longitudinal muscle of rat duodenum was not influenced by Ca2+. The difference in the effects of the smooth muscle stimulants on the tissue levels of cyclic GMP in two different smooth muscles in attributed to differences in the properties of guanylate cyclase of smooth muscles.

Animals

Retention of cadmium in the duodenum of the rat following oral administration.

The retention of cadmium in selected organs of the rat was studied following oral administration of the metal in the form of a carrier-free tracer and also as cadmium chloride. These 2 contrasting approaches (only the second being toxic) resulted in a similar retention pattern in the tissues. Both the cadmium burden and retention was greatest in the duodenum, followed by the kidney and the liver. This retention of cadmium in the duodenum following oral administration is relevant to the toxic effects of this metal associated with imparied calcium absorption in the intestine.

Administration, Oral

The contribution of protozoa to the protein entering the duodenum of sheep.

1. Four sheep, each fitted with a rumen fistula and a re-entrant cannula at the proximal duodenum were fed a semi-purified diet containing urea as the only nitrogen source. The quantities of total protozoal amino acid-N (TPAN) present in the rumen and entering the duodenum were determined when the mean rumen dilution rate (D) was low (0.034/h) and when D was increased to 0.078/h by the intraruminal infusion of artificial saliva. 2. Increasing the dilution rate had no significant effect upon the proportions of TPAN present in the total microbial amino-acid-N (TMAN) of the rumen fluid and duodenal digesta. With both dilution rates the mean proportion of TPAN in the duodenal TMAN (0.24) was markedly less than the equivalent proportion (0.45) found in the rumen fluid. 3. The daily flow of TPAN, as measured at the duodenal cannula at both dilution rates were equivalent to only 41% of the flow of TPAN as predicted from measurements of rumen outflow, indicating that a substantial proportion of rumen protozoal protein was retained within the rumen.

Amino Acids

Regional localization of activity of Clostridium perfringens type A enterotoxin in the rabbit ileum, jejunum, and duodenum.

Rabbit ileal, jejunal, and duodenal loops were exposed to purified enterotoxin from Clostridium perfringens type A and then perfused for comparative analysis of effects of the enterotoxin on each region of the intestine. Ileal loops responded with enhanced net secretion of fluid and sodium, inhibition of chloride and glucose uptake, and substantial sloughing of epithelial cells. The jejunum responded with fluid secretion, enhancement of sodium secretion only during the first 20 min, inhibition of chloride and glucose uptake, and substantial sloughing of epithelial cells. In the duodenum, transport of fluid, sodium, and chloride was significantly altered only during the first 20 min of perfusion, and significant inhibition of glucose uptake varied from one period to another. Epithelial damage was much less than that seen in the jejunum or ileum. Levels of fluid protein in all three sections corresponded closely to extent of tissue damage. In general, it was found that the severity of response to fixed doses of enterotoxin varied as follows: ileum greater than jejunum greater than duodenum.

Animals

Visualization of the longitudinal fold of the duodenum by computed tomography.

The longitudinal fold of the duodenum can be visualized by computed tomography (CT). Visualization of the fold helps localize the hepatopancreatic duct entrance into the duodenum. Many pathological processes of the head of the pancreas such as pancreatitis or malignancy can produce swelling involving the longitudinal fold, which can be visualized by CT.

Ampulla of Vater

Mechanisms of disposal of acid and alkali in rabbit duodenum.

Stripped duodenal mucosa of rabbits was mounted in Ussing chambers containing a Ringer solution gassed with 100% O2. The disappearance of acid or alkali from the mucosal solution of short-circuited tissue was measured with a pH stat while the serosal pH was kept at 7.4. The duodenum rapidly disposed of both acid and alkali; neither property was altered by gassing with N2 while iodoacetate was in the perfusing solutions. Prevention of release of CO2 from the mucosal chamber obliterated the early rapid phase of acid disposal by the mucosa while a similar maneuver in the serosal chamber increased the appearance of serosal acid without altering the rate of acid disposal. Gut sacs of rabbit duodenum in vitro and in vivo showed a positive correlation between acid disposal and the rate of luminal CO2 production. While acid disposal progressively decreased with time for the in vitro gut sacs, the in vivo gut sac showed no fatigue in this respect. Luminal acidification in the Ussing chamber was associated with a profound reduction in short-circuit current (Isc), partially reversible by elevation of the mucosal pH but not by luminal glucose. Our data suggest that acid disposal occurs in part by intraluminal neutralization and in part by diffusion into the mucosa.

Acid-Base Equilibrium

Physiological significance of secretin in the pancreatic bicarbonate secretion. I. Responsiveness of the secretin-releasing system in the upper duodenum.

In nine normal subjects intraduodenal pH was measured by means of a glass electrode placed in the passage from the first to the second part of the duodenum. The physiological variations in pH were simulated by intraduodenal injection of 2.5, 5, or 10 ml of 0.1 mol x 1(-1) HCl and subsequent neutralization by injection of bicarbonate. A total of 26 injections of acid was followed by a pH spike from a median pH of 7.0 to a median of pH 2.1 Median spike duration was 45 sec. The concentration of secretin in plasma increased from a median of 1.2 pmol x 1(-1) to a peak value of 2.2 pmol x 1(-1) after 4 min. It is concluded that the secretin response to a brief acidification of the first 4--6 cm of the duodenum is sufficient to explain the physiological variations in the concentration of secretin in human plasma.

Bicarbonates

[Effects of precursors and metabolites of catecholamines on motricity of isolated rat duodenum. Particular reference to dopamine].

Studying the effects, on the isolated rat duodenum motricity, of ten compounds precursors or metabolites of catecholamines, the following results were obtained: The direct metabolites of epinephrine and norepinephrine (metanephrine, normetanephrine), are either ineffective at concentrations below 5 X 10(-6) M, or weakly inhibitory at higher concentrations. Such inhibitory effects are prevented by alpha- and beta-blockers. 3-methoxy, 4-hydroxyphenylglycol and vanylmandelic acid have no significant effect. The catecholamine precursor, dopamine, the related compounds DOPA, 3 methoxytyramine, and to a lesser extent, 3-O methyl DOPA and homovanillic acid, have excito-motor effects at concentrations ranging mainly from 10(-7) M to 10(-5) M. At higher concentrations, the same compounds frequently exhibit inhibitory effects. The excito-motor effects might be due to a serotoninergic mechanism, since they are suppressed by the serotoninergic blocking agents methysergide and cyproheptadine. Furthermore, in the case of DOPA, we were able to establish a relationship between the excito-motor effects and duodenal serotonin stores. As for the inhibitory effects, they may be prevented by using alpha and beta blocking agents. Dihydroxyphenylacetic acid has no effect on the isolated rat duodenum motricity. The fact that dopamine and related compounds may have excitomotor effects at some concentrations, correlated with some physiopathological observations in man and animal allows some considerations about the eventual role of dopamine on intestinal motricity.

Animals