Duodenal contents

Meeroff JC, Go VLW, Phillips SF. Control of gastric emptying by osmolality of duodenal contents in man. Gastroenterology 1975 68 1144-1151. 

Bile acids have long been known to aid digestion of dietary fats, but are not essential. Some 50% of dietary fats are absorbed in rats where bile acids are diverted by biliary fistula.Similar results were found in man. This suggested that the micellar phase isolated by ultracentrifugation of duodenal contents was in fact composed of both bile-acid micelles and vesicles, a suggestion supported by a systematic study of the physical chemistry of fat digestion in human small bowel. 

Since there is no clear cause a definable aetiology is impossible. Symptoms have variously been ascribed to Helicobacter gastritis without ulcer, to reflux of duodenal contents into the stomach and to delayed gastric emptying, and to adverse effects of drugs. In many patients, however, symptoms are likely to be central nervous or psychological in origin. 

Gastroesophageal reflux. Reflux of the stomach and duodenal contents into the esophagus, which may sometimes occur normally, particularly in the distended stomach postprandially, or as a chronic pathological condition. Gastroesophageal. Pertaining to the stomach and esophagus, as the gastroesophageal junction. 

J. E. Staggers, O. Hernell, R. J. Stafford, and M. C. Carey, Physical-chemical behaviour of dietary and biliary lipids during intestinal digestion and absorption. 1. Phase behaviour and aggregation states of model lipid systems patterned after aqueous duodenal contents of healthy adult human beings, Biochemistry 29 2028-2040 (1990). 

B. Stcmby, A. NOnon, T. Mel in, and B. Borgstidm. Pancreatic lipolytic enzymes in human duodenal contents. Stand J. Gastroenterol, 26 859 (1991). 

The duodenal contents were washed out with 1.0 ml ice-cold saline and collected for amylase activity. 

When not in use, the cannula is sealed from the exterior by inserting a threaded plug which allows pancreatic juice to enter the duodenum in the normal manner (Fig. 2, part C). For collection of juice this plug is removed and a long obturator is inserted (Fig. 2, part D). The latter effectively isolates the pancreatic secretion from other duodenal contents. 

Secretin Secretin receptor 27-residue peptide amide Regulate pH of duodenal contents Solid-phase V -Boc chemistry... 

A curious method for determining the enzymatic activity of trypsin and of the duodenal content has been demonstrated on the cleavage of p-nitroanilides of some aminoacids [180]. The half-wave potential of p-nitroaniline reduction is more negative than that of the substituted derivatives and so the hydrolysis of the nitroanilides can be measured by the decrease of its reduction wave. 

L9a. Levitan, R., Golub, M., and Zetzel, L., Lactic dehydrogenase activity in saliva, bile, gastric Emd duodenal contents. Am. /. Digest. Diseases 5, 458-465... 

The authors postulated the following mechanisms acute exacerbation of chronic pancreatitis, a direct effect of pentagastrin on the pancreas, increased pancreatic secretion due to stimulation by gastric acid, reflux of duodenal contents or bile, arterial hypotension with local acidosis in the pancreas. 

Figure 6.3 Gastric fluid pH in response to the oral administration of famotidine or ranitidine to two horses, (a) Administration of 2 mg/kg famotidine stimulated no response in horse t whereas horse 2 has a substantial increase in gastric fluid pH that persisted for more than 10 h. (b) Administration of 6.6 mg/kg ranitidine had an intermediate effect in horse 1, gastric fluid pH intermittently increased and decreased. By comparison, horse 2 showed a substantial increase in gastric fluid pH that persisted for more than 10h. The pH response in horse 1 may also reflect in part, reflux of duodenal contents into the stomach in addition to, or instead of, a response to ranitidine.

Total volume of pancreatic juice, amount or concentration of bicarbonate, and activities of pancreatic enzymes are measured in duodenal contents. The enzyme most commonly measured is trypsin, but amylase, lipase, chy-motrypsin, and elastase may also be evaluated. The Lundh test consists of administering a standardized meal consisting of 5% protein, 6% fat, 15% carbohydrate, and 74% nonnutrient fiber. Advantages of the Lundh meal are that it provides a physiological stimulus to the pancreas and is simple to administer. However, administration of the meal prevents determination of the total enzyme and bicarbonate or secretory volume. Moreover, it provides inadequate or no stimu-... 

The NBT-PABA test of pancreatic function is based on the hydrolysis, by chymotrypsin, of a synthetic tripeptide— N-benzoyl-l-tyrosyl-p-aminobenzoic acid. The tripeptide, variously called NBT-PABA, BTP, or bentiromide, is administered orally together with a test meal to stimulate pancreatic secretion. BTP is specifically hydrolyzed by chymotrypsin in the duodenum to release PABA, which is subsequently absorbed in the intestinal tract and metabolized in the liver to hippurate and to PABA glucuronide and PABA acetylate. These arylamines are then excreted by the Iddney. In the presence of low chymotrypsin, as found in pancreatic insufficiency, less peptide is hydrolyzed, and therefore less chromogen is excreted in the urine or found in serum. Thus the amount of PABA detected in serum or urine is an indirect measure of chymotrypsin activity in duodenal content. 

Fig. 10.8 Variations with time (A, C) and meal gastric emptying (B, D) of HGL and HPL concentrations in duodenal contents during test meals in humans. Mean values and standard deviations were estimated from data...

Alfhough the hpolysis levels were found to increase in fhe duodenal contents, it is worth noting that the overall lipolysis levels at fhe Angle of Treitz reached only 59.4 5.6% with the hquid meal and 27.7 6.8% wifh fhe sohd meal. The hpolysis could not be complete because fhe duodenal contents were collected continuously at the Angle of Treitz for 15 minute periods and at the end of each period, the lipolysis of fhe aspirate was stopped in order to analyze the hpolysis products. The mean residence time of the meal lipids in fhe small intestine and hence their contact with lipases were therefore shortened artificially in comparison with the situation under normal physiological conditions. 

In order to estimate the stabihty of HGL and HPL hpase activities in duodenal contents during a test meal in humans, samples of duodenal contents collected at the Angle of Treitz by aspiration were incubated for three hours at 37 °C. Fig. 10.10 shows the residual hpase activities measured after 3 hours, as a function of the pH value of the sample. One can see that HGL activity is highly stable at acidic pH value (more than 80% residual activity at pH 2) whereas HPL activity drastically decreases at pH 4 with less than 20% residual activity recovered. Reverse stabilities are observed at pH values close to neutrality. HPL is highly stable at pH 7 with 95% residual activity recovered whereas HGL residual activity is around 5%. 

With the liquid meal, the duodenal lipolysis (Tab. 10.6) decreased only slightly when micronized orlistat powder was pre-mixed with the meal (74.5% of controls), and did not decrease at all when Xenical pellets were added in the course of the administration of the meal (115.7% of controls). The differences between treated and control groups were not significant. This lack of effect of orlistat as means of reducing fhe duodenal lipolysis was not correlated with the high level of HPL inhibition observed in fhe duodenal contents (Tab. 10.5). These paradoxical results were however supported and explained by fhe results of further in vitro experiments. The rates of HPL inhibition by orlistat were found to be similar wifh bofh types of meals (half-inhibihon time=5-6 min), but the finely pre-emulsified TG of fhe liquid meal were rapidly hydrolyzed by HPL before the enzyme was sig-nificanfly inhibited by orlistat (Carriere et al., 2001). 

Staggers JE, Hernell O, Stafford ly, and Carey MC. Physical-Chemical Behavior of Dietary and Biliary Lipids During Intestinal Digestion and Absorption. 1. Phase-Behavior and Aggregation States of Model Lipid Systems Patterned After Aqueous Duodenal Contents of Heal thy Adult Human-Beings. Biochemistry 1990 29 2028-2040. 

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