Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “GASTROINTESTINAL TRACT”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 829 records · Page 46Linked to original sources
PubMed1992

Immunocytochemical study of vasopressin-like immunoreactive material in the gastrointestinal tract of the hedgehog Erinanceus europeus.

A study was made of portions of the gastrointestinal tract including the stomach, duodenum, jejunum, ileum, colon and rectum, and the hypothalamus of hedgehogs using the peroxidase-antiperoxidase (PAP) method incubating paraffin embedded sections of 6-7 microns thickness in an anti-arginine-vasopressin serum at a dilution of 1:1000. Vasopressin-like immunoreactivity is present in cells of the epithelial layer of the intestinal mucosa ranging from the stomach to the rectum. In the stomach the numbers of these cells are very small although they increase in the small intestine. However, in the different portions of this latter organ no significant differences can be found. Both, in colon and rectum there are cells with vasopressin-like immunoreactive material although at higher concentrations than in the rest of the gastrointestinal (GI) tract. Immunoreactive material is present throughout the epithelial layer of the mucosa and in general the cells of the mucosa are of the open kind. Using the same antiserum and at similar dilution, both cells and nerve fibres containing vasopressin-like immunoreactivity were observed in hypothalamic sections of this animal species and were used as positive controls. It is concluded that in the gastrointestinal (GI) tract of the hedgehog there is a population of epithelial cells that contain a immunoreactivity vasopressin-like-peptide (referred to as vasopressin-like peptide (AV-LP) whose numbers increase in the distal sense.

Animals↗
PubMedDate not supplied

Substance P and neurokinin A are codistributed and colocalized in the porcine gastrointestinal tract.

Immunoreactive substance P and neurokinin A were measured with radioimmunoassay in extracts of different segments of porcine gastrointestinal tract using C-terminally directed antisera. In all segments, the concentrations of substance P and neurokinin A were similar. The largest concentrations of both peptides were found in the mid-colon. By gel chromatography and reversed-phase high pressure liquid chromatography the immunoreactivity in extracts from ileum eluted as homogenous peptides at the positions of synthetic substance P and neurokinin A, respectively. No neurokinin B was found. By immunohistochemistry of porcine duodenum, jejunum, ileum and mid-colon, identical localization patterns were found for substance P and neurokinin A, and the two peptides demonstrated by double immunofluorescence to be colocalized in the enteric nervous system of the ileum. We conclude that the tachykinins substance P and neurokinin A are codistributed and colocalized in the procine gastrointestinal tract and suggest that the two peptides are produced from a common precursor, beta- and/or gamma-preprotachykinin, in the same neurons.

Animals↗
PubMed1975

Distribution of chlorpromazine in the gastrointestinal tract of the rat and its effect on absorptive function.

The distribution of [14C]chlorpromazine was studied in segments of the gastrointestinal tract of the rat after an oral dose of 20 mg/kg (1-2 muc). The total radioactivity in the gastrointestinal tract was, respectively, 43.2 +/- 3.6, 28.9 +/- 2.2 and 14.1 +/- 1.1 (mean +/- S.E. percent administered dose) at 2, 6 and 24 hours after dosing. The maximum observed total radioactivity in the different segments occurred at different times after dosing. The percentage of total radioactivity present in each tissue as unchanged [14C]chlorpromazine decreased with time in all the tissues. At all time points, this parameter also showed a consistent pattern: % stomach greater than % duodenum greater than % jejunum greater than % ileum. The effect of chronic administration of [14C]chlorpromazine on intestinal absorptive function was studied by the everted sac technique. Mucosal transport of L-[14C]methionine was significantly inhibited (24.4% of control), but no effect on transport of D-[14C]xylose was observed.

Animals↗
PubMed1997

Capsaicin-resistant vagal afferent fibers in the rat gastrointestinal tract: anatomical identification and functional integrity.

The presence and distribution of vagal fibers and terminals throughout esophagus and gastrointestinal tract that could be anterogradely labeled by nodose ganglion tracer injections was quantitatively assessed in capsaicin- and vehicle-pretreated adult rats, in order to identify the capsaicin-resistant population. Up to 90% of the intraganglionic laminar endings (IGLEs), in the myenteric plexus of the esophagus, and 70-90% in the stomach, as well as 57% of the intramuscular endings or arrays (IMAs) in the fundic stomach survived the capsaicin treatment, while in the upper small intestine only few and in the lower small intestine, the cecum and colon, virtually no IGLEs survived capsaicin treatment. Intramucosal terminals were not assessed. Furthermore, gastric balloon distension-induced c-Fos expression in the dorsal vagal complex was not significantly decreased in capsaicin-treated rats. It is concluded that among primary vagal afferents there is a capsaicin-resistant population that primarily innervates the esophagus and upper gastrointestinal tract, and a capsaicin-sensitive population that innervates mainly the lower tract. At least vagal gastric tension-sensitive afferents also seems to be functionally intact in that they may be capable of synaptically activating second-order neurons in the brainstem.

Animals↗
PubMed1998

Effect of moderate exercise on blood flow in the gastrointestinal tract in trained conscious miniature swine.

AIM: To examine how moderate exercise affects the blood flow in the gastrointestinal tract. MATERIALS AND METHODS: Twelve miniature swine weighing 38-43 kg were used. All animals were trained on a cardiac exercise treadmill. Blood flow measurements were done on conscious animals using labeled microspheres with a diameter of 16.5 +/- 0.1 (SD) microm. The first flow was measured while the animal was awake and resting, the second flow after 15 min of exercise, the third flow after 30 min of rest. RESULTS: Flow in the oesophagus at rest was 19.5 +/- 1.3 (SEM) ml/min/100 g. During exercise the flow decreased to 13.3 +/- 1.2 (SEM) ml/min/100 g (ns). After 30 min of rest the flow was 9.9 +/- 1.2 (SEM) ml/min/100 g (p < 0.05 when comparing the flow before and after exercise). Flow in the cardia at rest was 23.1 +/- 1.3 (SEM) ml/min/100 g. During exercise the flow decreased to 14.0 +/- 1.2 (SEM) ml/min/100 g (p < 0.05). After 30 min of rest the flow was 15.0 +/- 1.2 (SEM) ml/min/100 g. Flow in the pylorus at rest was 38.9 +/- 1.1 (SEM) ml/min/100 g. During exercise the flow decreased to 24.6 +/- 1.1 (SEM) ml/min/100 g (p < 0.01). After 30 min of rest the flow was 26.9 +/- 1.2 (SEM) ml/min/100 g. Blood flow in the small and large intestine was mainly unaffected by moderate exercise. CONCLUSION: Under moderate exercise, blood flow in the upper part of the gastrointestinal tract declines while it is mainly unaffected in the duodenum, small and large intestine.

Analysis of Variance↗
PubMed1985

Sensation in the gastrointestinal tract.

There are similarities between sensation in the gastrointestinal tract (GI tract) and somatic sensation. This review concentrates on parasympathetic (vagal) components of GI sensation rather than the sympathetic (splanchnic) elements. A wide range of enteroceptors have been described over the whole length of the gut which subserve several different sensory modalities. Fibres from these enteroceptors project to the medulla, primarily to the nucleus of the solitary tract. In the medulla there is considerable integration of afferent information from different parts of the GI tract. Regulatory peptides are present both in the brain and in the GI tract. It is likely that these peptides may play a role in the modulation of sensory information in the medulla. Parallels may be drawn at a receptor level between somatic sensation and sensation in the GI tract. More centrally, sensory mechanisms relating to the gut seem less highly organized than in somatic sensation. This reduced influence of the central nervous system in GI tract sensation may be explained by the presence in the gut of a highly sophisticated intrinsic nervous system, the enteric nervous system, which pre-programmes many of the functions of the GI tract.

Afferent Pathways↗
PubMed2004

Targeting nitric oxide in the gastrointestinal tract.

This review discusses the contributions of the three nitric oxide (NO) synthase (NOS) isozymes neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS) to the function and diseases of the gastrointestinal tract. Small (nanomolar) quantities of NO produced by calcium-dependent nNOS play a physiological role in peristalsis and sphincter function of the intestine. Decreased nNOS function can result in aperistalsis and obstructive sphincters. NO produced by eNOS dilates mucosal blood vessels and prevents leukocyte aggregation, and is therefore essential for the maintenance of mucosal blood flow. Absence of eNOS-derived NO results in an increased susceptibility of the gastrointestinal tract to injury. Selective NO delivery by gene therapy or NO-donating compounds may offer new therapeutic options in motility disorders of the gut and the prevention of mucosal injury. The effects of large (micromolar) amounts of NO as produced by iNOS are less well understood. Large amounts of NO can increase gut permeability, induce apoptosis and stimulate intestinal secretion, while NO can also kill bacteria, block apoptosis and reduce inflammation by inhibiting activation of nuclear factor-kappaB (NFkappaB). Lumenal donation of NO could therefore block NFkappaB activation and be a treatment option in inflammatory conditions of the bowel.

Animals↗
PubMed1984

Localization of Met5-enkephalin-Arg6-Phe7-like immunoreactivity in the rat gastrointestinal tract.

The distribution of Met5-enkephalin-Arg6-Phe7 (Met-Enk-Arg-Phe)-like immunoreactivity in the rat gastrointestinal tract was studied by immunohistochemical techniques. Antiserum against a Met-Enk-Arg-Phe-thyroglobulin conjugate was raised in rabbits and was found to be specific for synthetic Met-Enk-Arg-Phe. Met-Enk-Arg-Phe-like immunoreactivity was found in neuronal structures in all parts of the rat gastrointestinal tract. Immunostained somata were primarily located in myenteric plexus; immunostained processes were mostly present in myenteric plexus and circular muscle layer. This distribution pattern is similar to that of the three other opioid polypeptides, Met5-enkephalin, Leu5-enkephalin and Met5-enkephalin-Arg6-Gly7-Leu8.

Animals↗
PubMed1986

Pharmacological effects of oral saikosaponin a may differ depending on conditions of the gastrointestinal tract.

Saikosaponin a and its 8 derivatives, structural isomers and their monoglycosides and aglycones, which were formed in the gastrointestinal tract with their fecal contents depending on food intake, showed different effects on protein synthesis by rat hepatocytes in primary culture. Saikosaponin a and its monoglycoside and aglycone were detectable in plasma of rats when saikosaponin a was orally administered. Pharmacological effects of saikosaponin a when orally administered may differ depending on conditions of the gastrointestinal tract.

Animals↗
PubMed1992

Diffuse aggressive B-cell lymphomas of the gastrointestinal tract. An immunophenotypic and gene rearrangement analysis of 22 cases.

Twenty-two diffuse aggressive B-cell lymphomas of the gastrointestinal tract were studied using light microscopic examination, immunohistochemical methods, and Southern blot analysis. The results suggest that diffuse aggressive B-cell gastrointestinal tract lymphomas may be divided into two groups: large cell lymphomas and small noncleaved cell lymphomas. Large cell lymphomas often involve the stomach; commonly express the lymphocyte adhesion molecules CD44, LFA-1 (CD11a and CD18), and CD54; and may express monotypic cytoplasmic immunoglobulin in approximately one third of cases. Southern blot analysis demonstrates rearrangements of the c-myc gene that do not co-migrate with rearrangements of the immunoglobulin heavy chain gene, as detected with a JH probe in approximately one half of the cases. Small noncleaved cell lymphomas typically involve the ileocecal region. In these lesions, monotypic cytoplasmic immunoglobulin is not detected, and the CD44 and LFA-1 molecules usually are not expressed, particularly in small noncleaved cell lymphomas of the Burkitt type. The CD54 antigen is positive in fewer than one half of cases. Southern blot studies often demonstrate rearrangements of the c-myc gene that co-migrate with immunoglobulin heavy chain gene rearrangements indicative of the t(8;14) chromosomal translocation, with the c-myc region translocated into the immunoglobulin heavy chain gene joining region. Thus, immunohistochemical and genotypic results, in accordance with the site of involvement and histologic findings, suggest a different pathogenesis for large cell lymphomas and small noncleaved cell lymphomas. The findings in large cell immunoblastic lymphomas are more akin to those of the large cell group. In addition, immunophenotypic and molecular data may be helpful in improving histologic classification when the morphologic findings are equivocal.

Adult↗
PubMed1985

Localization of calcitonin gene-related peptide-like immunoreactivity in neurons of the rat gastrointestinal tract.

Calcitonin gene-related peptide (CGRP)-like immunoreactivity was localized in neuronal processes and somata of the rat gastrointestinal tract. Varicose processes were observed in the myenteric and submucosal plexuses, smooth muscles, submucosa, mucosa and around blood vessels. Immunoreactive somata were visualized in the myenteric and submucosal ganglia of the intestine in colchicine-treated rats. These observations, together with previous neuroanatomical and pharmacological studies, suggest that CGRP may be involved in regulatory functions of the gastrointestinal tract.

Animals↗
PubMed1981

Routine early endoscopy in upper-gastrointestinal-tract bleeding: a randomized, controlled trial.

To determine whether routine early endoscopy is beneficial to patients with upper-gastrointestinal-tract bleeding that ceases during hospitalization, we randomly assigned 206 patients to routine endoscopy (100 patients) or no routine endoscopy (106). Patients in the latter group underwent endoscopy only if recurrent bleeding occurred during hospitalization or if x-ray films disclosed gastric ulcer or suggested neoplasia. All patients were initially treated with an empiric antacid regimen. When the two groups were compared (experimental versus control), there were no significant differences in overall hospital deaths (11 versus eight), recurrence of bleeding (33 versus 32), number of transfusions required to treat recurrent bleeding (mean +/- S.E.M., 7.4 +/- 1.2 versus 6.3 +/- 0.7 units), deaths after recurrent bleeding (eight versus five), or duration of hospital stay. During the 12 months after discharge, there were also no significant differences in frequency of readmission to the hospital, incidence of further gastrointestinal bleeding, number of hemorrhage-related deaths, or frequency of gastrointestinal surgery. We conclude that endoscopy should not be a routine procedure in patients with upper-gastrointestinal-tract bleeding that ceases during treatment.

Clinical Trials as Topic↗
PubMed2005

The clinical and nutritional implications of lipid-lowering drugs that act in the gastrointestinal tract.

PURPOSE OF REVIEW: A new class of cholesterol-lowering therapy that reduces intestinal sterol absorption has recently been introduced. This increases the number of classes of lipid-lowering agents that directly affect gastrointestinal function and raises questions concerning the overall effect of these agents on absorption and nutritional status. RECENT FINDINGS: A recent assessment notes a paucity of information concerning the factors that affect the bioavailability and intestinal absorption of lipophilic nutrients. By contrast, the specificity of the mechanisms of action of new drugs acting on the gastrointestinal tract may circumvent some of the detrimental effects on nutrient and drug bioavailability that have been noted with older forms of treatment. SUMMARY: The clinical imperative for aggressive control of lipid and metabolic risk factors makes widespread use, alone or in combination, of lipid-lowering agents that affect the gastrointestinal tract seem increasingly likely. Whilst the opportunity for therapeutic synergy is attractive, care will be required to avoid interference with intestinal absorptive function.

Animals↗
PubMed1984

Ranitidine versus cimetidine in the management of acute upper gastrointestinal tract bleeding.

Ranitidine and cimetidine were compared with respect to their effect on preventing the continuation or recurrence of acute upper gastrointestinal bleeding secondary to peptic ulcer disease. Fifty patients were randomly allocated to treatment with either ranitidine or with cimetidine. The two groups were comparable for age, sex, and severity of hemorrhage. There was no statistically significant difference in outcome between the groups when assessing need for surgery, total number of units in blood required, days in hospital, incidence of rebleeding, or deaths. However, there was a trend in favor of ranitidine: only one ranitidine-treated patient went to operation versus four of the cimetidine group. In addition, the number of rebleeds was higher in the cimetidine group (14) compared to the ranitidine group (1). Two patients in each group died. Therefore, ranitidine appears to be comparable to cimetidine in the management of patients with acute upper gastrointestinal tract bleeding. However, this study did not include a placebo group, and thus the generalized use of H2-receptor blockers in all patients with acute upper gastrointestinal tract bleeding has not been proven.

Acute Disease↗
PubMed2004

Xanthelasmas of the upper gastrointestinal tract.

BACKGROUND: Gastric xanthelasma is a benign and uncommon lesion with a variably reported frequency, while esophageal and duodenal xanthelasmas are quite rare. METHODS: Seventeen patients who had the diagnosis of xanthelasma in the upper gastrointestinal tract were analyzed retrospectively with respect to their demographic, clinical, endoscopic, and histopathologic features. All lesions suspected as xanthelasma were totally removed by either hot biopsy forceps or a snare with the technique of endoscopic mucosal resection. RESULTS: The incidence of upper gastrointestinal xanthelasmas in 7320 patients who had upper gastro-intestinal endoscopy was 0.23%. There were 9 (53%) men and 8 (47%) women, with a median age of 50 years (range, 24-80 years). The most common location of xanthelasmas was the stomach (76%), followed by the esophagus (12%) and duodenum (12%). All lesions were observed as yellow-white colored plaques at endoscopy. Multiple xanthelasmas were detected in 4 patients (24%); in the duodenum in 2, esophagus in 1, and stomach in 1. One patient had xanthelasma within a gastric hyperplastic polyp. The size of the lesion was less than 5 mm in diameter in 14 (82%) patients and between 5 and 10 mm in diameter in 3 (18%). Thirteen (76%) patients had moderate to severe atrophic gastritis, while the remainder had normal gastric mucosa. CONCLUSIONS. Xanthelasmas of the upper gastrointestinal tract were mostly located in the stomach in the present series, which includes the second and third reported cases of duodenal xanthelasma, the second case of xanthelasma developed within a hyperplastic gastric polyp, and the fourth and the fifth cases of esophageal xanthelasma.

Adult↗
PubMed1986

Effect of feeding on myoelectric activity of the sphincter of Oddi and the gastrointestinal tract in the opossum.

The effect of different foods on the myoelectric activity of the sphincter of Oddi and gastrointestinal tract was evaluated in the opossum. Gallbladder pressure was also recorded. Feeding fat and mixed food resulted in the greatest incidence of spike activity in the duodenum and jejunum, followed by protein. The lowest incidence of slow waves with spikes in the duodenum and jejunum followed feeding of carbohydrates (P less than 0.01). Likewise, the lowest spike activity in the sphincter of Oddi was observed after carbohydrate feeding (P less than 0.05). There was no significant difference in the incidence of spike potentials in the sphincter of Oddi when fat, protein, or mixed food was fed. No significant change in gallbladder pressure during fasting and following feeding of different aliments was observed. We concluded that there is a correlation between the frequency of spike potentials in the sphincter of Oddi and in the small bowel following feeding. The duration of the fed pattern for each type of food correlated with the number of spikes in the sphincter of Oddi and gastrointestinal tract.

Ampulla of Vater↗
PubMed1989

[Characterization of drug absorption from the gastrointestinal tract with the use of numeric deconvolution].

The present investigation is concerned with the absorption of drugs from the gastrointestinal tract. The duration of absorption of drugs was calculated using numerical deconvolution. Clinical data were obtained from the literature. The absorption of 36 different drugs is characterized. The results show that the duration of absorption is not uniform. Penicillins and tetracyclines are absorbed for about 3 hours after application. Most drugs are absorbed during 4 to 6 hours. A few drugs, e.g. theophylline or metoprolol, are absorbed for more than 12 hours from the gastrointestinal tract.

Humans↗