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Results for “Digestive System Physiological Phenomena”

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PubMedDate not supplied

[Physico-chemical properties related to gastrointestinal function of 6 sources of dietary fiber].

The physicochemical properties of the six sources of dietary fiber more commonly consumed in Mexico were studied. The knowledge of these properties may allow a prediction of the functional effect of the fibers on the GI tract. The content of dietary fiber varied from 43% in wheat bran (WB) to 87% in Psyllium plantago (PP). Glucomannan (GM) showed the highest proportion of soluble fiber (97%) followed by dried cactus from Opuntia sp (DC) (28%) and PP (13%), whereas WB and soy isolate (SI) showed the highest proportion of insoluble fiber (95 and 92%, respectively). PP and GM showed a higher water holding capacity and viscosity and a lower ion exchange capacity: we anticipate that these fibers would be more effective to regulate plasma levels of glucose and cholesterol in contrast, WB and SI with a lower water holding capacity and viscosity and a higher proportion of insoluble fiber would be more effective to increase fecal bulk. Fibers from DC and from cactus fiber isolate were intermediate in these responses.

Absorption↗
PubMed1985

Symposium on infections in the compromised host. External barriers to infection.

Knowledge of the external barriers to infection is the first step in understanding the normal defense mechanisms of the host. The intact skin and mucous membranes, with their normal flora and secretions, the action of cilia in the upper respiratory tract, secretory functions, and the normal flow of body fluids are all important factors associated with the external defense against infections. When these barriers are altered or breached, the potential for infection increases and the internal immune system is activated to assist in defending the body.

Bacterial Infections↗
PubMedDate not supplied

Development of gastrointestinal and pancreatic functions in mammalians (mainly bovine and porcine species): influence of age and ingested food.

This review summarizes recent advances in knowledge on the development of digestive tissues and their productions as well as mechanisms of regulation in response to age and ingested food in mammalian species (mainly bovine and porcine species). In the first two sections, changes are reported for stomach, pancreas and small intestine, and examined in relation to different situations (colostral, milk feeding and weaned periods). The implication of some regulatory substances (growth factors, gut regulatory peptides and neurohormonal substances) in regulation mechanisms is discussed over these periods. For example, the plasma pattern of several gut regulatory peptides and the expression of their specific receptors could explain certain phenomena of digestive development. Recent cellular and molecular aspects of regulation of the digestive enzyme production are also reported. Finally, an approach to interactions existing between age and ingested food is given in the last section. In conclusion, although some phenomena are well established, it is often difficult to distinguish what the age- and food-dependent events are in the development of the digestive function.

Aging↗
PubMed1999

Development of the human gastrointestinal tract: twenty years of progress.

A combination of approaches has begun to elucidate the mechanisms of gastrointestinal development. This review describes progress over the last 20 years in understanding human gastrointestinal development, including data from both human and experimental animal studies that address molecular mechanisms. Rapid progress is being made in the identification of genes regulating gastrointestinal development. Genes directing initial formation of the endoderm as well as organ-specific patterning are beginning to be identified. Signaling pathways regulating the overall right-left asymmetry of the gastrointestinal tract and epithelial-mesenchymal interactions are being clarified. In searching for extrinsic developmental regulators, numerous candidate trophic factors have been proposed, but compelling evidence remains elusive. A critical gene that initiates pancreas development has been identified, as well as a number of genes regulating liver, stomach, and intestinal development. Mutations in genes affecting neural crest cell migration have been shown to give rise to Hirschsprung's disease. Considerable progress has been achieved in understanding specific phenomena, such as the transcription factors regulating expression of sucrase-isomaltase and fatty acid-binding protein. The challenge for the future is to integrate these data into a more complete understanding of the physiology of gastrointestinal development.

Aging↗
PubMed2004

Stochastic resonance-like phenomena in the context of the alimentary tract.

External noisy stimulation induces Ca(2+) binding protein dynamics synchronization. Cell coupling chain fluctuation may lead to internal order facilitating information (generation and propagation). Body rhythms require cellular synchronization by interaction between nonlinear biological systems in a fluctuating environment. Could stochastic resonance add or subtract efficacy in digestive tolerogenic selection or disease?

Animals↗
PubMed1986

Immunocytochemical identification and localization of peptide hormones in the gastro-entero-pancreatic (GEP) endocrine system of the mouse and a stomachless fish, Barbus conchonius.

A large number of antisera mainly raised against mammalian hormones are tested immunocytochemically on the GEP-endocrine system of mouse and fish (Barbus conchonius). The endocrine pancreas of mouse and fish appeared to contain the same four endocrine cell types; insulin-, glucagon-, PP- and somatostatin-immunoreactive cells. In mouse about 13 GEP endocrine cell types are distinguished: 1. insulin-, 2. somatostatin-, 3. glucagon-, 4. PP-, 5. (entero)glucagon-/PP-like, 6. CCK-like, 7. substance P-, 8. neurotensin-, 9. VIP-, 10. gastrin-, 11. secretin-, 12. beta-endorphin-, 13. serotonin-immunoreactive cells. Based on this and a previous study at least 13 GEP endocrine cell types seems to be present in stomachless fish: 1-9 as described for mouse, 10. (entero)glucagon-like, 11. met-enkephalin, 12. VIP-like, 13. unspecific immunoreactive endocrine cells. Coexistence of glucagon and PP-like peptides is found in the gut and pancreas of mice and in the gut of B. conchonius. In mouse pancreas and fish gut, endocrine cells showing only PP- or glucagon-like immunoreactivity are found too. In mouse stomach some endocrine cells showing only PP-immunoreactivity are demonstrated. In the same region coexistence of C-t-gastrin- and FMRF-amide-immunoreactivity is found in endocrine cells. The importance of these phenomena are discussed. Enteric nerves immunoreactive with antisera raised against substance P and GRP are found in mouse, against somatostatin and met-enkephalin in both mouse and fish and against VIP in fish.

Animals↗
PubMed1977

[Significance of in-vitro studies ofr the evaluation of gastrointestinal motility].

To study the function of the smooth muscles taken from the gastrointestinal tract the simple organ bath or various superfusion techniques can be used. With the aid of these methods it is possible to measure contractile and electrical phenomena of the isolated muscles. In addition the reactivity to various stimuli can be tested. Such in-vitro-systems elucidate principal questions of physiology, pathophysiology, and pharmacology. However, there is no direct clinical significance of in-vitro-investigations of gastrointestinal motility up til now. The clinical benefit of such investigations can be seen in the better understanding of the pathophysiology and in the discovery of new drugs in the field of gastrointestinal motility.

Digestive System Physiological Phenomena↗
PubMedDate not supplied

Effects of protein malnutrition and endotoxin on the intestinal mucosal barrier to the translocation of indigenous flora in mice.

Since protein malnourished or endotoxemic patients are at increased risk of developing nosocomial infections with enteric organisms, we investigated the effects of these risk factors alone and in combination on the intestinal mucosal barrier to bacteria. Protein malnutrition resulted in severe ileal atrophy that was directly related to the length of time the mice were protein malnourished. Although protein malnutrition did not promote bacterial translocation from the gut to systemic organs, the protein-malnourished mice were more susceptible to endotoxin-induced bacterial translocation than normally nourished mice (p less than 0.01). Since the gross epithelial damage documented after endotoxin administration in normally nourished mice was diminished after protein malnutrition, there was no correlation between the gross appearance of the epithelial mucosal barrier and the extent of endotoxin-induced bacterial translocation. These results suggest that the synergistic effect of endotoxin plus protein malnutrition on bacterial translocation is not primarily related to failure of the gut mucosal barrier. Nonetheless, it appears that protein-malnourished mice are less able to clear translocating bacteria than normally nourished mice.

Animals↗
PubMed1997

The effects of vagotomy on bacterial translocation: an experimental study.

The effects of truncal vagotomy and proximal gastric vagotomy on bacterial translocation in rats were investigated in this experiment. The rats were divided into three groups. Only esophageal and gastric manipulations were performed in the control group (Group I). The anterior and posterior vagi were found and 0.5- to 1-cm pieces were taken out in the truncal vagotomy + pyloric dilatation group. In addition, pyloric dilatation was performed using a Fogarty catheter (Group II). The branches of the vagi, which lead to the rumen and corpus, were first tied with 5/O silk and then resected in the proximal gastric vagotomy group (Group III). All animals were sacrificed on the 7th day. Qualitative and quantitative tissue cultures of cecum, liver, spleen, mesenteric lymph node, and blood from vena cava were taken and a tissue sample from the ileum was obtained for histopathological examination with light microscopy. At the end of microbiologic study, the bacterial concentration on the cecal wall was 10.68 x 10(8) in the truncal vagotomy group, while it was 0.53 x 10(8) in the proximal gastric vagotomy group. Bacterial translocation was observed more in vagotomy groups than in control groups on the mesenteric lymph node, liver, and spleen. Bacterial translocation was greater in the truncal vagotomy group than in the proximal gastric vagotomy group (P < 0.05). Bacterial translocation was observed mostly in the liver, spleen, and mesenteric lymph node in the proximal gastric vagotomy group. No microorganisms could be cultured on systemic blood cultures. Cultures were positive only for one rat in the proximal gastric vagotomy group and for two rats in the truncal vagotomy group. At the end of histopathologic examination, when histopathologic parameters given for each rat were calculated, they were 5.44 +/- 2.12 in the truncal vagotomy group and 4.77 +/- 2.12 the in proximal gastric vagotomy group. The difference between these two groups was statistically significant (P < 0.05). Thus, there was damage to the intestinal wall in vagotomy groups, and it was greater in the truncal vagotomy group than in the proximal gastric vagotomy group. It was observed that bacterial translocation occurs after vagotomy, that this translocation occurs more after truncal vagotomy than after proximal gastric vagotomy, and that the translocation that occurred after vagotomies was not effective enough to create bacteremia.

Animals↗
PubMed1980

Bacterial translocation from the gastrointestinal tract of athymic (nu/nu) mice.

The immune system may be one host defense mechanism preventing viable indigenous bacteria from translocating from the mouse gastrointestinal lumen to the mesenteric lymph nodes, spleen, liver, or kidney. The role of T-cell-dependent immunity in preventing bacteria from translocating from the gastrointestinal tract was tested with congenitally athymic nude (nu/nu) mice, heterozygous (nu/+) mice, and thymus-grafted nude (nu/nu) mice. Viable bacteria were cultured from 50% of the mesenteric lymph nodes, spleens, livers, and kidneys of athymic (nu/nu) mice, whereas heterozygous (nu/+) mice exhibited viable bacteria in only 5.2% of these organs. Both aerobic and strictly anaerobic bacteria were cultured from these organs with Escherichia coli and Lactobacillus predominanting. Grafting thymuses to the athymic (nu/nu) mice restored their immunological responses to sheep erythrocyte antigens. The incidence of bacterial translocation from the gastrointestinal tract was reduced from 50% in the athymic (nu/nu) mice to 7.8% in the thymus-grafted (nu/nu) mice. Thus, T-cell-dependent immunity restored by thymic grafts inhibited the translocation of certain indigenous bacteria from the gastrointestinal tract to the spleen, liver, and kidney in nu/nu mice.

Animals↗