Assessment of ischemic vascular damage.
Authors: Nosál'ová V, Sotníková R
Abstract
This protocol describes a model convenient for acute experiments in anesthetized rats, performed by selective occlusion of the superior mesenteric artery. Such a model provides a means for assessing the role played by various pathophysiological mechanisms in the development of intestinal ischemic injury. It is especially suitable for studying different treatments, mainly pharmacological ones, to help cope with this problem in clinical practice. In the form of support protocols, this unit includes functional vascular and chemiluminescence studies, determination...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
Measurement of gastric acid secretion in the anaesthetized rat.
Authors: Adami M, Coruzzi G
Abstract
The protocols described in this unit are designed to assess the effects of substances on gastric acid secretion by the rat stomach, with the animal under general anesthesia. Both stimulatory and inhibitory effects of compounds can be evaluated and specific mechanisms of action can also be investigated. Acid secretion is induced by substances that directly activate parietal cell receptors (histamine and bethanechol), by indirect stimuli, like 2-deoxy-D-glucose, by electrical stimulation of vagal nerves, or by the peptide pentagastrin. Reference antisecretory drugs are re...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
Endogenous gastric mediators: patho-physiological role and measurements.
Authors: Konturek SJ, Bielanski W, Konturek PC, Brzozowski T
Abstract
The protocols described in this unit are designed to present the major endogenous gastric mediators involved in the control of gastric acid secretion, namely gastrin and histamine, and in the regulation of gastric motility, which include motilin and ghrelin, under physiological and pathological conditions. The measurement of these mediators in plasma or serum of humans and animals by radioimmunoassay are described and their pathophysiological role is discussed.
PMID: 20967748 [PubMed - indexed for MEDLINE] (Source: Current Protocols in Toxicology)
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
Measurement of small intestinal damage.
Authors: Takeuchi K, Satoh H
Abstract
Many animal models have been devised for investigating the pathogenesis of intestinal lesions and for screening drugs for the treatment of intestinal ulcers in humans. Recently, particular attention has been focused on NSAID-induced intestinal lesions as a result of the development of the capsule endoscope and double-balloon endoscope. Ischemic enteritis, one of the most dramatic abdominal emergencies, is known to cause severe damage to the small intestine by a significant decrease of arterial blood flow in the small intestine. In this unit, two animal models for small...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
Assessment of gastrointestinal motility using three different assays in vitro.
Authors: Pozzoli C, Poli E
Abstract
The protocols detailed in this unit are designed to assess the motor activity of different gastric and intestinal muscle preparations in vitro and the effects of drugs that modulate gastrointestinal motility. The preparations described are characterized by different contractile behaviors, consisting of spontaneous (duodenum), neurogenic (ileum), and drug-stimulated (fundus, ileum) motility; these reproduce motility patterns occurring in the gut wall in vivo. These protocols document the variety of factors that can influence the responses of isolated tissues and describe ...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
Assessment of gastrointestinal propulsive activity using three different models of peristalsis in vivo in the mouse.
Authors: Poli E, Pozzoli C
Abstract
The protocols described in this unit are designed to assess the acute effects of drugs on the propulsive activity of the gastrointestinal muscles in the conscious mouse. These protocols are currently applied to investigate the pharmacological activity of novel compounds undergoing preclinical development and to obtain predictive data needed to advance drugs into clinical trials. Moreover, these methods could be useful in evaluating the functional toxicity by environmental or alimentary pollutants, like xenobiotics and naturally occurring toxins endowed with noxious activ...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
Role of integrative signaling through gap junctions in toxicology.
Authors: Upham BL
Abstract
Gap junctional intercellular communication (GJIC) plays a central role in coordinating signal-transduction pathways that control gene expression inside of cells with those of neighboring cells in maintaining the homeostasis of a tissue. The normal homeostatic set point of gap junctions within tissues is in an open state, and although transient closure of gap junctions in response to mitogenic effectors is normal, chronic closure of channels by continuous exposure to environmental and food-borne contaminants can result in adverse health effects such as cancer, teratogenesis, repro...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
Caco-2 cells as a model for intestinal absorption.
Authors: Angelis ID, Turco L
Abstract
The Caco-2 cell system, a well characterized intestinal in vitro model, makes it possible to evaluate the ability of chemicals to cross the intestinal barrier, as well as to study their transport mechanisms. Permeability values estimated with this model correlate well with human in vivo absorption data for many drugs and chemicals. As a consequence, the use of the Caco-2 cellular model as a permeability assay to predict oral absorption in humans is growing, and its importance is increasing as a screening tool in drug-discovery strategies for the prediction of intestina...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
Stem cells in toxicology.
Authors: Lawrence D
PMID: 21400684 [PubMed - indexed for MEDLINE] (Source: Current Protocols in Toxicology)
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
Using chemotherapeutic drugs to trigger hematopoietic stem cell activation and determine hematological toxicity.
Authors: Boles N
Abstract
Hematopoietic stem cells (HSCs) replenish blood cells throughout the lifetime of an animal. Maintaining the HSC pool is of paramount importance to the survival of the organism. Thus, when treating a patient or an animal with chemotherapeutic agents, all care must be taken to ensure that the HSC pool is minimally damaged while simultaneously eradicating the target population. Discussed here is a method to assess the potency of chemotherapeutic drugs on the hematopoietic system, their ability to activate the HSC compartment, and the damage done to the HSC pool.
PMID: 2140068...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
Isolation and applications of prostate side population cells based on dye cycle violet efflux.
Authors: Gangavarpu KJ, Huss WJ
Abstract
This unit describes methods for digestion of human prostate clinical specimens and dye cycle violet (DCV) staining for identification, isolation, and quantitation of radiolabeled dihydrotestosterone (DHT) retention of side population cells. The principle of the side population assay is based on differential efflux of DCV, a cell-membrane-permeable fluorescent dye, by cells with high ATP-binding cassette (ABC) transporter activity. Cells with high ABC transporter activity that efflux DCV and fall in the lower left quadrant of a flow cytograph are designated as "side ...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
LC-MS/MS quantitation of mercapturic acid conjugates of lipid peroxidation products as markers of oxidative stress.
Authors: Kuiper HC, Stevens JF
Abstract
Oxidative stress-induced lipid peroxidation (LPO) leads to the formation of cytotoxic and genotoxic 2-alkenals. LPO products such as 4-hydroxy-2(E)-nonenal (HNE) and 4-oxo-2(E)-nonenal (ONE) have been the subject of many studies due to their association with the development of cardiovascular and neurodegenerative diseases, as well as cancer. LPO products are excreted in the urine after conjugation with glutathione (GSH) and subsequent metabolism to mercapturic acid (MA) conjugates. Urinary LPO-MA metabolites are stable end-product metabolites and have gained interest...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
Cellular fura-2 manganese extraction assay (CFMEA).
Authors: Kwakye GF, Li D, Kabobel OA, Bowman AB
Abstract
Cellular manganese (Mn) uptake and transport dynamics can be measured using a cellular fura-2 manganese extraction assay (CFMEA). The assay described here uses immortalized murine striatal cell line and primary cortical astrocytes, but the method is equally adaptable to other cultured mammalian cells. An ultrasensitive fluorescent nucleic acid stain for quantification of double-stranded DNA (dsDNA) in solution, Quant-iT PicoGreen, has been utilized for normalization of Mn concentration in the cultured cells, following Mn (II) chloride (MnCl(2)) expos...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
Fluorescence correlation spectroscopy: detecting and interpreting the mobility of transmembrane proteins in vivo.
Authors: Malchus N
Abstract
Mobility of proteins is crucial for their functionality. Fluorescence correlation spectroscopy (FCS) is a sensitive tool for assessing dynamics in vivo. It can reveal properties of diffusing proteins, as well as of the surrounding medium. Hence, subtle changes in the dynamics after treatment with toxic substances can be visualized. On biological membranes, the high concentration of transmembrane and peripheral membrane proteins leads to molecular crowding, and thus to a change in the diffusion behavior, i.e., to anomalous diffusion of membrane proteins. Presented here is a proto...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
High-throughput assays for assessing mitochondrial dysfunction caused by compounds that impair mtDNA-encoded protein levels in eukaryotic cells.
Authors: Nadanaciva S, Murray J, Wilson C, Gebhard DF, Will Y
Abstract
Compounds that impair the synthesis of either mitochondrial DNA (mtNDA) or mtDNA-encoded proteins reduce the levels of 13 proteins essential for oxidative phosphorylation, leading to a decrease in mitochondrial ATP production. Toxicity caused by these compounds is seldom identified in 24 to 72 hr cytotoxicity assays due to the low turnover rates of both mtDNA and mtDNA-encoded proteins. Here, we describe three high-throughput screening assays that detect compounds that affect mtDNA-encoded protein levels. All three assays measure the le...
Source: Current Protocols in Toxicology - December 21, 2015 Category: Toxicology Tags: Curr Protoc Toxicol Source Type: research
