Biliary control of beta-glucuronidase activity in the luminal contents of the rat ileum, cecum, and rectum.

The effect of bile exclusion on intestinal beta-glucuronidase activity was studied in the rat. Bile exclusion dramatically decreased the bacterial beta-glucuronidase activity in the cecum and rectum but did not affect the normal low level in the ileum. Thus, bile flow may be the most important factor in modulating beta-glucuronidase activity in the rat large bowel. Dietary substances which can alter bile flow may thus have effects on intestinal bacterial beta-glucuronidase activity. Effects of diet on colon cancer might therefore be explicable in terms of altered bile flow rather than altered bacterial beta-glucuronidase induction.

The hemicellulose component of dietary fiber.

The digestion of hemicellulose in humans was investigated with subjects with an ileostomy and subjects with healthy small and large bowel on a fixed diet of known fiber content. It was shown that an average of 65% of the hemicelluloses were digested by women ileostomy subjects and 83% by men ileostomy subjects and 97% in the intact women subjects and 95% in the intact men subjects. The monosaccharide composition of the hemicelluloses in the diet, small bowel excreta and feces, suggest that an arabinoxylan hemicellulose from cereals, is not digested in the small bowel and only partly digested in the large bowel. This study suggests that it is the arabinoxylans from cereals that are important components of dietary fiber.

Pectin digestion in humans.

The digestibility of pectin, a component of dietary fiber was investigated in humans. The groups studied comprised healthy people with intact gastrointestinal tracts, and patients who had undergone total colectomy followed by ileostomy in the management of ulcerative colitis. The pectin content of the individual plant foods in the diet and the pectin content of the excreta were determined. Some loss of pectin occurred in the small intestine but most of the pectin was degraded in the large intestine.

Digestion of certain fractions of dietary fiber in humans.

The digestion of cellulose, hemicellulose, and lignin has been investigated in humans. Two groups of subjects were studied--healthy subjects with an ileostomy and normal subjects. Both were put on a fixed diet of known cellulose, hemicellulose, and lignin content. From the feces excreted the fiber components were measured by the acid and neutral detergent method. From the small bowel 84.5% of the ingested cellulose was excreted from the ileostomy subjects. From the normal subjects 22.4% of the ingested cellulose was excreted, indicating approximately 80% of the cellulose was digested in the normal subjects. From the water insoluble ingested hemicelluloses 27.5% were excreted from the small bowel, 4.0% from normal subjects. That is approximately 96% digestion of the hemicelluloses in normal subjects. Lignin was found to be undigested in both the small and large bowel. This has important implications in future fiber research.

Sucralfate interactions with gastric mucus.

Sucralfate protects the stomach against a number of experimental damaging agents and is efficacious in the treatment of peptic ulcer disease. It binds with acidity to the base of an ulcer to form a protective barrier. Sucralfate also enhances prostaglandin synthesis and release in the mucosa. In this study, the rat stomach was examined to determine sucralfate's interaction with gastric mucus. Mucus in the rat stomach forms a distinct and continuous blanket. In snap-frozen samples, pretreatment with phosphate-buffered saline as a control shows a layer of mucus of homogeneous structure thinner than the homogeneous layer after pretreatment with antibodies developed against rat gastric mucus. Pretreatment with the surface protective agent sucralfate shows some increase in the thickness of mucus with a thin dense sublayer adjacent to the epithelium and a less dense-appearing outer zone of variable thickness. Analysis of x-rays generated by the electron beam on windows of mucus and epithelium showed the expected gradients of sodium, potassium, chloride, and sulfur. The percentage of aluminum and sulfur in the mucus was higher in sucralfate-treated samples than in controls. Interaction between sucralfate and gastric mucus needs further investigation.

Pancreatic cancer mucin from xenografts of SW1990 cells: isolation, characterization, and comparison to colon cancer mucin.

Mucin has been purified from nude mouse xenografts of SW1990 human pancreatic cancer cells. The mucin was eluted at the void volume of Sepharose CL-4B and was of density greater than 1.3 in CsCl gradients. The isolated mucin had a high content of threonine, serine, and proline, with 31% of the amino acid residues O-glycosylated. The average oligosaccharide composition was NeuAc1.8Fuc0.7Gal2.0GlcNAc1.7GalNAc1.4. Polyclonal rabbit antibodies prepared against the purified mucin recognized primarily mucin polypeptide, and there was extensive immunological cross-reaction between SW1990 pancreatic cancer mucin and LS174T colon cancer mucin. However, using carbohydrate-specific monoclonal antibodies, the two mucins were found to differ. SW1990 mucin had more Lewis, sialyl Lewis, and sialyl Lewis activity, while the colon cancer mucin had more sialyl T antigen. Since pancreatic mucins, whether from normal pancreas or pancreatic cancer, have not previously been well characterized, the availability of SW1990 pancreatic cancer mucin may be useful as a model for studying the expressing of organ-specific or cancer-associated antigens.

The clinical associations with hepatic steatosis: a retrospective study.

Hepatic steatosis is a common liver biopsy finding. As a preamble to a study of nonA, nonB hepatitis we aimed to determine the clinical associations in patients who had hepatic steatosis on biopsy. All liver biopsies performed in the gastroenterology department at Auckland Hospital between 1986 and 1989 were reviewed for evidence of steatosis and the clinical associations analysed. Steatosis was present in 69 (43.7%) of 158 liver biopsy specimens with 35 being mild (47%), 29 moderate (45%) and five severe (7%). Excess alcohol intake was the probable aetiological association in 28 (45%), obesity in 17 (27%) and diabetes mellitus in seven (11%). No causal association could be identified in 17 (24%) and included three of the five cases with severe steatosis. There were no significant differences in clinical presentation, biochemistry or hepatic histopathology between alcoholic and nonalcoholic steatosis. Nonalcoholic steatosis appeared to be more benign with only one case of cirrhosis but further follow up is required to determine true prognosis.

Incidence of acquired primary hypolactasia in three New Zealand racial groups.

The relative frequency of acquired primary hypolactasia has been determined in adult Maoris, Samoans and Europeans by measuring an alteration in breath hydrogen concentration two hours after a 50 g oral lactose load. By this indirect measurement hypolactasia was present in 64% of Maoris, 54% of Samoans and 9% of Europeans. The differences between Maoris and Europeans (p less than 0.001) and between Samoans and Europeans (p less than 0.001) were significant.

Towards an accurate measurement of dietary fibre.

A method of acid and neutral detergent extraction of food has been used to measure the cellulose, hemicellulose and lignin content of a number of New Zealand foods. Foods can be classified as those high or relatively high in hemicellulose and those high or relatively high in cellulose and lignin. The accurate determination of this fibre content is of importance in understanding the physical, chemical and bacteriological effects of various fibre components in preventing or causing disease.

Tripotassium dicitrato-bismuthate tablets v liquid in the treatment of duodenal ulcers.

Thirty-five patients with duodenal ulcers were treated with tripotassium dicitrato-bismuthate (TDB) in a double-blind, double-dummy endoscopically controlled trial. Healing rates were comparable in patients treated with either tablet or liquid, 74% and 72% at four weeks and 89% in both groups at eight weeks. It is concluded that the tablet formulation of TDB is as effective as the liquid in the treatment of acute duodenal ulceration.

Pathogenesis of peptic ulcer disease and gastritis: importance of aggressive and cytoprotective factors.

Acid production is a major gastric function. Second messengers (cyclic AMP and calcium) are released when parietal cell membrane receptors (H2, muscarinic and gastrin) are stimulated. The second messengers then stimulate the 'gastric proton pump' to produce hydrogen ions. New evidence suggests that there is a unidirectional flux of hydrogen ions into the lumen induced by unique physical properties of mucus and a sodium gradient from lumen to serosa. Luminal hydrogen ions, bile salts, ingested drugs, and ingested alcohol are potential gastric epithelial toxins. The stomach's protective mechanism includes a well-defined mucus layer, an epithelial bicarbonate secretion, a tight epithelium, and a good nutrient blood supply. Endogenous prostaglandins partly control these mechanisms. Modern therapeutics are increasingly directed towards improving gastric cytoprotection.