Search results for "Intestine"
showing 10 items of 390 documents
Influence of gamma-aminobutyric acid on baclofen intestinal absorption.
1994
Since previous studies suggested that baclofen absorption in the rat middle intestine was inhibited by beta-alanine and therefore mediated, at least in part, by the beta-aminoacid carrier, we focused our new studies on the analysis of the possible inhibition of the drug by a gamma-aminoacid model compound, gamma-aminobutyric acid (GABA). A rat jejunum in situ study was undertaken in order to evaluate the effect of GABA on baclofen absorption and to establish the inhibition model. Assays using isotonic perfusion solutions of 0.5 mM baclofen with starting GABA concentrations ranging from 0 to 100 mM are reported. The results show that the absorption rate pseudoconstants of the drug decrease a…
Partially competitive inhibition of intestinal baclofen absorption by beta-alanine, a nonessential dietary aminoacid.
1991
In situ intestinal absorption of baclofen in the rat in the presence of beta-alanine has been investigated. Through the perfusion of 0.50 mM baclofen solutions containing variable concentrations of the aminoacid (from 5 to 100 mM), a partially competitive inhibition of baclofen absorption was characterized: absorption rate pseudoconstants of the spasmolytic drug decrease as beta-alanine concentration increases, until a limiting value is obtained (36.8 per cent of that found for baclofen alone). A computer method was developed in order to calculate parameters governing baclofen absorption in the presence of beta-aminoacid, with the following results: Vm = 11.22 mM h-1; Km = 7.42 mM; Ki = 2.4…
Kinetics of the intestinal uptake of zinc acexamate in normal and zinc-depleted rats.
1990
Abstract The uptake of zinc as acexamic acid salt in the small intestine of the anaesthetized rat was shown to be a two-phase process in normal animals. The first phase is rapid mucosal binding which satisfies the Freundlich isotherm equation and which involves about 30 per cent of the initially perfused zinc. The second phase was characterized as an apparent absorption step which obeys Michaelis-Menten and first-order combined kinetics, with the following parameters: Vm = 6.51 mg h−1; Km = 2.96 mg; ka = 0.306 h−1. In largely non-saturated conditions, an apparent global rate constant of about 2.50 h−1 was calculated. No significant interference due to endogenous zinc excretion into the smal…
Intestinal absorption pathway of gamma-aminobutyric acid in rat small intestine.
1994
Intestinal absorption of gamma-aminobutyric acid (GABA), as a model compound for gamma-aminoacids, has not been extensively studied from the kinetic viewpoint. Since data from our laboratory suggested that some competition arises between intestinal absorption of beta-alanine and GABA and since our intent was to maintain the aqueous stagnant diffusion layer in order to approach absorption tests to in vivo physiological conditions, a rat jejunum in situ study was undertaken in order to gain an insight into the mechanism of GABA absorption. In the present paper, results from assays using isotonic perfusion solutions with starting GABA concentrations ranging from 1 to 50 mM are reported. They s…
Age-dependent shift-to-the-right in the localization of colorectal adenomas.
1987
The age-dependent prevalence and topographical distribution of colorectal adenomas was investigated in 1006 unselected autopsies (554 males and 452 females) in Mainz, FRG. In 200 out of 1006 autopsies (19.8%) a total of 498 adenomas of the large intestine were detected. The percentage of patients with adenomas increased continuously with age. Only 6% of all adenomas were localized in the caecum and 8% in the rectum, whereas all the other adenomas were distributed rather evenly throughout the ascending colon (23%), the transverse colon (25%), the descending colon (15%) and the sigmoid colon (23%). Analyzing the topographical distribution of adenomas for definite age groups (40-59, 60-69, 70-…
The intestinal microbiota modulates the anticancer immune effects of cyclophosphamide
2013
The Microbiota Makes for Good Therapy The gut microbiota has been implicated in the development of some cancers, such as colorectal cancer, but—given the important role our intestinal habitants play in metabolism—they may also modulate the efficacy of certain cancer therapeutics. Iida et al. (p. 967 ) evaluated the impact of the microbiota on the efficacy of an immunotherapy [CpG (the cytosine, guanosine, phosphodiester link) oligonucleotides] and oxaliplatin, a platinum compound used as a chemotherapeutic. Both therapies were reduced in efficacy in tumor-bearing mice that lacked microbiota, with the microbiota important for activating the innate immune response against the tumors. Viaud et…
Effect of lactose, lactulose and bisacodyl on gastrointestinal transit studied by metal detector.
2007
SUMMARY Aim and methods: To study the effect of 45 g lactose, 30 g lactulose and 10 mg bisacodyl on gastrointestinal transit in 30 healthy volunteers by metal detector and Hinton marker method. The first set of measurements were performed under standard conditions. In a second stage, transit was slowed to twice the original value by loperamide to simulate constipation conditions. Results: Bisacodyl drastically accelerated small and large intestinal transit. Colonic transit was shortened to 23 % and to 31% of control values, without and with loperamide. Bisacodyl increased stool weight and decreased stool consistency in all persons. Lactulose marginally shortened small intestinal transit (P=…
Posttranslationally modified proteins as mediators of sustained intestinal inflammation.
2006
Oxidative and carbonyl stress leads to generation of N(epsilon)-carboxymethyllysine-modified proteins (CML-mps), which are known to bind the receptor for advanced glycation end products (RAGE) and induce nuclear factor (NF)-kappaB-dependent proinflammatory gene expression. To determine the impact of CML-mps in vivo, RAGE-dependent sustained NF-kappaB activation was studied in resection gut specimens from patients with inflammatory bowel disease. Inflamed gut biopsy tissue demonstrated a significant up-regulation of RAGE and increased NF-kappaB activation. Protein extracts from the inflamed zones, but not from noninflamed resection borders, caused perpetuated NF-kappaB activation in cultured…
Meconium microbiota types dominated by lactic acid or enteric bacteria are differentially associated with maternal eczema and respiratory problems in…
2013
Background Culture-dependent methods have shown that meconium, the newborn's first intestinal discharge, is not sterile, but the diversity of bacteria present in this material needs to be further characterized by means of more sensitive molecular techniques. Objective Our aims were to characterize molecularly the meconium microbiota in term infants, to assess whether it contributes to the future microbiota of the infants' gastrointestinal tract, and to evaluate how it relates to lifestyle variables and atopy-related conditions. Methods We applied high-throughput pyrosequencing of the 16S rRNA gene to study the meconium microbiota in twenty term newborns from a Spanish birth cohort. For comp…
Daily follow-up of bacterial communities in the human gut reveals stable composition and host-specific patterns of interaction
2012
In the last decade, an extensive effort has been made to characterize the human intestinal microbiota by means of SSU rRNA gene sequence and metagenomic analysis. Relatively few studies have followed intestinal bacterial communities over time to assess their stability in the absence of perturbation. In this study, we have monitored the faecal bacteria of three healthy subjects during 15 consecutive days. The global community structure was analysed through SSU rRNA gene sequencing. In agreement with previous studies, we found that the between-subject variation in community structure was larger than within. The composition was fairly stable throughout, although daily fluctuations were detecte…