Differential dietary effects on colonic and small bowel neoplasia in C57BL/6J Apc Min/+ mice.

The effects of fiber on colon cancer are controversial. Twenty 5-week old C57BL/6J Apc Min/+ mice were fed for 60 days with a commercial mouse diet (Teklad LM-485) and eight semidefined diets containing 5-10% various fibers and 20% soybean oil. Ten additional C57BL/6J congenic litter-mates were fed each diet to assay colonic SCFA.

Mechanism of gastroprotection by bismuth subsalicylate against chemically induced oxidative stress in cultured human gastric mucosal cells.

Reactive oxygen species (ROS) are implicated in the pathogenesis of chemically induced gastric mucosal injury. We have investigated the effects of ethanol, hydrochloric acid (HCl), and sodium hydroxide (NaOH) on: (1) enhanced production of ROS including superoxide anion and hydroxyl radicals, (2) modulation of intracellular oxidized states by laser scanning confocal microscopy, and (3) DNA fragmentation, indices of oxidative tissue, and DNA damage in a primary culture of normal human gastric mucosal cells (GC), which were isolated and cultured from Helicobacter pylori-negative endoscopic biopsies from human subjects. The induction of ROS and DNA damage in these cells following exposure to ethanol (15%), HCl (150 mM) and NaOH (150 mM) were assessed by cytochrome c reduction (superoxide anion production), HPLC detection for enhanced production of hydroxyl radicals, changes in intracellular oxidized states by laser scanning confocal microscopy, and DNA damage by quantitating DNA fragmentation.

Acute and chronic stress-induced oxidative gastrointestinal mucosal injury in rats and protection by bismuth subsalicylate.

Reactive oxygen species (ROS) are implicated in the pathogenesis of stress-induced gastrointestinal mucosal injury. In the present study, we have investigated the effects of acute and chronic stress on the enhanced production of ROS including superoxide anion [SA; as determined by cytochrome c reduction (CCR)] and hydroxyl radicals (OH), and correlated the enhanced production of these free radicals with increased lipid peroxidation, membrane microviscosity and DNA fragmentation, indices of oxidative tissue damage, in the gastric and intestinal mucosa of female Sprague-Dawley rats. Furthermore, the protective ability of bismuth subsalicylate (BSS) against the gastrointestinal mucosal injury induced by acute and chronic stress was determined.

Effect of pepper and bismuth subsalicylate on gastric pain and surface hydrophobicity in the rat.

Background: The mechanism by which dietary pepper causes dyspepsia and epigastric pain is poorly understood, as is the ability of bismuth subsalicylate (BSS) to relieve these symptoms.

Aim: To investigate the ability of black pepper, red pepper and BSS to affect gastric surface hydrophobicity and induce/relieve visceral pain in rat model systems.

Methods: Fasted rats were administered intragastrically Vivonex containing varying concentrations of either black or red pepper (0-200 mg/mL) and gastric contact angles were read after 1-24 h.

Stress, diet and alcohol-induced oxidative gastrointestinal mucosal injury in rats and protection by bismuth subsalicylate.

Oxygen free radicals are implicated in the pathogenesis of stress and food/alcohol-induced gastrointestinal injury. We have investigated the effects of restraint stress, spicy food diet, high-fat diet and 40% ethanol on the enhanced production of reactive oxygen species, including superoxide anion and hydroxyl radicals, and on DNA fragmentation, lipid peroxidation and membrane microviscosity (indices of oxidative tissue damage) in gastric and intestinal mucosa of Sprague-Dawley rats. Furthermore, the protective ability of bismuth subsalicylate (BSS; 15 mg kg(-1) was determined against the gastrointestinal mucosal injury induced by these stressors.

Protection against chemically-induced oxidative gastrointestinal tissue injury in rats by bismuth salts.

Oxygen free radicals (OFR) are implicated in the pathogenesis of stress, chemically induced gastric lesions, and gastrointestinal injury. The concentration-dependent scavenging abilities of bismuth subsalicylate (SBS), colloidal bismuth subcitrate (CBS), and selected OFR scavengers, including superoxide dismutase (SOD), catalase, mannitol, and allopurinol were examined against biochemically or chemically generated superoxide anion, hydroxyl radical, and hypochlorite radical plus hypochlorous acid based on a chemiluminescence assay. Furthermore, both gastric (GM) and intestinal mucosa (IM) were individually exposed in vitro to these free radical generating systems, and the concentration-dependent protective abilities of SBS and CBS against lipid peroxidation (LP) were compared with selected OFR scavengers.

Cytoprotective effect of bismuth subsalicylate in indomethacin-treated rats is associated with enhanced mucus bismuth concentration.

Background: Bismuth compounds prevent gastric injury from the short-term administration of nonsteroidal anti-inflammatory drugs. We studied the mechanisms underlying the gastroprotective actions of bismuth subsalicylate against indomethacin-induced injury in rats.

Methods: An in vivo microscopic technique was used in which acid output, surface cell intracellular pH (pHi), gastric mucus gell thickness and mucosal blood flow were measured simultaneously.

Comparative effects of nabumetone, naproxen, piroxicam, and diclofenac on rat gastric irritancy following acute exposure to OTC non-steroidal anti-inflammatory agents and other gastric irritants.

This study examined the relative effects of equally-effective anti-inflammatory doses of nabumetone, naproxen, piroxicam and diclofenac on gastric irritancy induced by over-the-counter (OTC) non-steroidal anti-inflammatory drugs (NSAIDs) aspirin and ibuprofen and a variety of necrotizing agents (0.6 N HCl, 0.2 N NaOH and 25% NaCl).

Effects of nicotine and ethanol on rat atrial membrane potentials.

The purpose of this research was to study the effects of nicotine and ethanol, alone and in combination, on cardiac membrane potentials (MP). Rat atrial preparations driven at 5 Hz were superfused with Tyrode's solution (37 degrees C) while recording MP with intracellular microelectrodes. Nicotine concentrations below and including 6.

Cardiac chronotropic effects of nicotine and ethanol in the rat.

The purpose of this research was to study the chronotropic effects of ethanol (ETOH) and nicotine (NIC), alone and in combination, on the heart. Rat sinoatrial preparations superfused with Tyrode's solution (37 degrees C) were used. The sinoatrial rate (SAR) was monitored using intracellular microelectrodes.

Actions and interactions of dihydropyridines and ethanol on the rat sinus node.

The actions and interactions of dihydropyridines (DHPs) and ethanol on sinus node (SN) automaticity were studied using rat sinoatrial preparations superfused with Tyrode's solution at 37 degrees C. Intracellular microelectrodes were used to monitor SN rate (SNR). The automaticity of the SN was not affected by nimodipine 10(-10) M, but it was depressed by a higher concentration of this calcium antagonist (10(-8) M).