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At least 91 records · Page 5Linked to original sources
PubMed1987

Surgical approach to malignant melanoma in the gastrointestinal tract.

The gastrointestinal (GI) tract is a common site for malignant melanoma. Diagnosis of lesions in the GI tract is usually delayed until complications occur, such as obstruction, bleeding, or perforation of the GI tract. Of 348 patients with malignant melanoma treated during a 10-year period, 11 had GI involvement either in a metastatic form or as a primary melanoma. Three of these patients were treated surgically for metastatic lesions in the small bowel causing intussusception, two for peritonitis secondary to perforation of the small bowel, and one for massive bleeding from metastatic melanoma in the stomach. Another patient had a primary melanoma in the esophagus and underwent esophagectomy. Three patients had primary melanomas of the anal canal and one of the rectum. Three of them underwent abdominoperineal resections, and two had bilateral groin dissection in addition. Six of the patients are alive 6 months to 4 years following diagnosis. The remaining five died of metastatic melanoma from 6 months to 4 years post-surgery.

Adult↗
PubMed2003

Distribution of the vanilloid receptor (VR1) in the gastrointestinal tract.

The gastrointestinal (GI) tract responds to a variety of stimuli through local and centrally mediated pathways. Changes in the intestinal microenvironment are sensed by vagal, spinal, and intrinsic primary afferent fibers. Sensory nerve endings located close to the lumen of the GI tract respond to pH, chemical composition of lumenal contents, or distortion of the mucosa. Afferents within the muscle layers are thought to be tension sensitive, whereas those located within the myenteric plexus are also thought to respond to changes in chemical composition and humoral substances. Subpopulations of these afferent fibers are activated by capsaicin. However, the exact location of these nerves is currently not known. The vanilloid receptor (VR1) is a nonselective cation channel that is activated by capsaicin, acid, and temperature. Antibodies to VR1 make it possible to determine the location of these afferents, their morphology, and their relationships with enteric nerves and other cell types in the GI tract. VR1-like immunoreactivity was observed on nerves within myenteric ganglia and interganglionic fiber tracts throughout the GI tract. VR1 nerves were also observed within the muscle layers and had an irregular profile, with varicose-like swellings along their lengths. Blood vessels within the GI wall had VR1-immunoreactive nerve fibers associated with them. VR1-like nerves and other immunopositive cells were also observed within the mucosa. In summary, VR1-like immunoreactivity was found in several locations within the GI tract and may provide sensory integration of chemical, physical, or inflammatory stimuli. VR1-like fibers appear to be predominantly spinal in origin, but a few vagal VR1-like fibers exist in the stomach.

Afferent Pathways↗
PubMed1997

Recombinant galectin-1 recognizes mucin and epithelial cell surface glycocalyces of gastrointestinal tract.

Rat gastrointestinal (GI) tract is rich source of galectins, a family of mammalian galactoside-binding lectins. To determine which tissue component is the relevant glycoconjugate ligand for the galectins, we produced recombinant galectin-1 and surveyed its binding sites on tissue sections of rat GI tract. Mucin and epithelial surface glycocalyces of both gastric and intestinal mucosa were intensely stained. This finding raises the possibility that some GI tract galectins known to be secreted by the epithelia may recognize these glycoconjugates and crosslink them into a macromolecular mass. This galectin-ligand complex may play a role in protecting the epithelial surface against luminal contents such as gastric acid, digestive enzymes, and foreign organisms.

Animals↗
PubMed2003

Expression and regulation of antimicrobial peptides in the gastrointestinal tract.

The gastrointestinal (GI) tract is exposed to a wide range of microorganisms. The expression of antimicrobial peptides has been demonstrated in different regions of the GI tract, predominantly in epithelial cells, which represent the first host cells with which the microorganisms have to interact for invasion. The intestinal epithelial monolayer is complex, consisting of different cell types, and most have a limited lifespan. Of the GI antimicrobial peptides, alpha- and beta-defensins have been studied the most and are expressed by distinct types of epithelial cells. Enteric alpha-defensin expression is normally restricted to Paneth and intermediate cells in the small intestine. However, there are important differences between mice and humans in the processing of the precursor forms of enteric alpha-defensins. Parasite infection induces an increase in the number of enteric alpha-defensin-expressing Paneth and intermediate cells in the murine small intestine. In the chronically inflamed colonic mucosa, metaplastic Paneth cells (which are absent in the normal colon) also express enteric alpha-defensins. Epithelial expression of beta-defensins may be constitutive or inducible by infectious and inflammatory stimuli. The production of some members of the beta-defensin family appears to be restricted to distinct parts of the GI tract. Recent studies using genetically manipulated rodents have demonstrated the likely in vivo importance of enteric antimicrobial peptides in innate host defense against microorganisms. The ability of these peptides to act as chemoattractants for cells of the innate- and adaptive-immune system may also play an important role in perpetuating chronic inflammation in the GI tract.

Amino Acid Sequence↗
PubMed1987

Effect of cisapride on the concentrations of beta-endorphinlike immunoreactivity and substance P-like immunoreactivity in the rat gastrointestinal tract.

Cisapride is a gastrointestinal prokinetic agent reported to be devoid of direct cholinergic effect from the myenteric plexus of the gut. The effect of cisapride (0.125, 0.5, 2mg/kg, i.p.) on the concentration beta-endorphin and substance P in rat gastrointestinal tract was studied. beta-Endorphinlike immunoreactivity contents were significantly increased in both mucosal and muscular layers of the entire gastrointestinal tract (from gastric body to rectum) of the rats treated with 2 mg/kg of cisapride. beta-Endorphinlike immunoreactivity contents were also increased in a part of the gastrointestinal tract of the rats treated with 0.125 or 0.5 mg/kg of cisapride. Substance P like immunoreactivity contents were significantly decreased in muscular layers of the rectosigmoid colon of the rats treated with 2 mg/kg of cisapride. This study suggests that the prokinetic effects of cisapride may relate to the contents of beta-endorphinlike immunoreactivity and substance P like immunoreactivity in gastrointestinal tract.

Animals↗
PubMed2002

Schwannomas of the gastrointestinal tract: clinicopathological features of 12 cases including a case of esophageal tumor compared with those of gastrointestinal stromal tumors and leiomyomas of the gastrointestinal tract.

We analyzed the clinicopathological features of 12 gastrointestinal (GI) schwannomas and compared them with those of 37 GI stromal tumors (GISTs) and 15 leiomyomas. Grossly, the schwannomas showed rubbery to firm, yellow-white to tan, glistening, and often trabeculated cut surfaces, resembling soft tissue schwannomas. The GISTs were firm to soft or fish-flesh tan, gray-pink, or variegated tumors with a degenerative change, and the leimyomas resembled typical uterine leiomyomas. Histologically, GI schwannomas were moderately cellular tumors with focal significant nuclear pleomorphism and rare mitotic figures. A characteristic peripheral lymphoid cuff was observed in all cases, but was indistinct in two cases. The GISTs were highly cellular spindle cell, epithelioid or, occasionally, pleomorphic tumors with basophilic appearance. Leiomyomas were paucicellular tumors with eosinophilic appearance. Immunohistochemically, schwannomas were S-100 protein- and glial fibrillary acidic protein (GFAP)-positive, but were negative for c-kit, CD34, and smooth muscle actin (SMA). GISTs were all c-kit- and/or CD34-positive, but GFAP-negative. Leiomyomas were SMA-positive and were negative for c-kit, CD34, S-100 protein, and GFAP. The mean Ki-67 index of schwannoma was 0.7, and those of GIST and leiomyoma were 5.9 and 0.3, respectively. The patients with schwannomas and leiomyomas had a favorable outcome, whereas 12 patients with GISTs showed progression and died of disease. The separation of GISTs from schwannomas is clinically important because the former group has a high risk of malignant behavior. GI schwannomas differed from the conventional soft tissue schwannomas in that they had peripheral lymphoid cuffs, lacked fibrous capsule and vascular hyalinization, and rarely showed degenerative changes. GI schwannomas, however, resembled soft tissue schwannomas in many aspects, and the clinical, gross, histological, and immunohistochemical features were different from those of GISTs and leiomyomas.

Adult↗
PubMed2005

Expression and immunolocalization of aquaporin-7 in rat gastrointestinal tract.

BACKGROUND INFORMATION: In the gastrointestinal tract of mammals, water can either be secreted with digestive juices or absorbed by the small and large intestine. Transcellular water movement can be mediated by the transmembrane protein family of AQPs (aquaporins), as has also been recently identified in the gastrointestinal tract. However, the localization, expression and functioning of AQPs in the gastrointestinal tract have not been completely characterized. For the present study, we investigated: (1) the expression of AQP7 in some portions of rat gastrointestinal tract by semiquantitative reverse transcriptase-PCR and by immunoblotting and (2) the cellular and subcellular localization of AQP7 by immunohistochemistry. RESULTS: AQP7 mRNA and proteins were highly expressed in the small intestine, weakly in the caecum, colon and rectum and were absent in the stomach. Immunoblotting analysis using rat gastrointestinal tract membrane fractions showed two major bands corresponding to a molecular mass of approx. 34 and 40 kDa for the AQP7 protein. No bands were observed when the anti-AQP7 antibody was preadsorbed with the immunizing peptide. Immunohistochemistry revealed strong AQP7 labelling in the surface epithelial cells of duodenum, jejunum, ileum, caecum, colon and rectum, whereas weak or no labelling was observed in the crypt cells. The labelling was manifest particularly in the apical membrane but intracellular staining was also observed. CONCLUSIONS: The results indicate that AQP7 is present in the small and large intestine. The higher expression of AQP7 protein at the apical pole of the superficial epithelial cells suggests its involvement in rapid fluid movement through the villus epithelium.

Animals↗
PubMed1993

[Primary lymphoma of the gastrointestinal tract].

Lymphomas of the gastrointestinal tract are rare tumors with unusual features and few characteristics. Clinical, radiological and endoscopic diagnosis is difficult, because they may be confused with inflammatory or neoplastic forms, especially in primary involvement of the gastrointestinal tract. From 1965 we observed 4 patients with primitive gastrointestinal tract lymphomas. Prognostically important features for GI lymphomas were: stage, site of the primary disease, histological type. Authors report on the clinical findings, diagnostic procedures, surgical treatment and results.

Adolescent↗
PubMed2004

The physiological and pathophysiological roles of eosinophils in the gastrointestinal tract.

Eosinophils and the gastrointestinal tract interact in an intimate and enigmatic relationship. Under healthy conditions, the presence of eosinophils is limited almost exclusively to the digestive tract mucosa where they exert several effector and immunoregulatory functions. While their precise function in the gastrointestinal tract is not completely understood, it is likely that, together with different T cell subsets, eosinophils are involved in maintaining the immunologic homeostastis across the mucosal barrier under resting conditions. Eosinophils also play a role in several inflammatory conditions, such as intestinal infections, hypersensitivity reactions, primary eosinophilic inflammations and several other chronic intestinal disorders. Depending on the responsible trigger, their effects may be beneficial or detrimental. Here, we discuss the available information regarding the physiological and pathological functions of eosinophils within the gastrointestinal tract.

Digestive System↗
PubMed1999

Duplications of the gastrointestinal tract.

BACKGROUND: Gastrointestinal duplications are rare, benign congenital lesions that may occur at any location along the alimentary tract and generally require surgical intervention. Presenting symptoms may be quite varied even among patients with the same anomaly. OBJECTIVE: To review the clinical presentation of gastrointestinal duplications and present our experience with such lesions over the past decade. METHODS: The records of all patients treated for gastrointestinal duplications at a tertiary hospital during 1987 through 1996 were collected, and relevant published literature reviewed. RESULTS: In the nine patients with gastrointestinal duplications, six were in the small bowel and one each in the cecum, colon and esophagus. Presenting clinical features were varied and often subtle. Perinatal ultrasonography, radioscintography and computerized tomography were useful in some cases, while in others the correct diagnosis was established only at surgery. CONCLUSIONS: Alimentary tract duplications are uncommon, and may present as solid or cystic tumors, intussusception, perforation or gastrointestinal bleeding. A high index of suspicion is required when dealing with such cases. Appropriate investigations, including imaging techniques, should be directed toward adequate and planned surgery.

Digestive System Abnormalities↗
PubMed1991

[Endoscopic assessment of hemorrhage from the gastrointestinal tract].

The causes of gastrointestinal bleedings was assessed by fiber gastroscopy, rectoromanoscopy and fiber colonoscopy. The most frequent causes of bleedings from the upper gastrointestinal tract are gastric and duodenal ulcers, erosive hemorrhagic gastritis, gastric cancer, liver cirrhosis with bleeding from varicose veins, polyps, diverticuli, Mallory-Weiss syndrome, etc. The most frequent causes of bleedings from the lower gastrointestinal tract are hemorrhoids, anal fissures, colonic polyps, chronic ulcerohemorrhagic colitis, rectal carcinoma, etc. The diagnostic importance of urgent endoscopic examinations is pointed out.

Emergencies↗