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Bohley M, Leroux J. Gastrointestinal Permeation Enhancers Beyond Sodium Caprate and SNAC - What is Coming Next? ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2400843. [PMID: 38884149 PMCID: PMC11434117 DOI: 10.1002/advs.202400843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/13/2024] [Indexed: 06/18/2024]
Abstract
Oral peptide delivery is trending again. Among the possible reasons are the recent approvals of two oral peptide formulations, which represent a huge stride in the field. For the first time, gastrointestinal (GI) permeation enhancers (PEs) are leveraged to overcome the main limitation of oral peptide delivery-low permeability through the intestinal epithelium. Despite some success, the application of current PEs, such as salcaprozate sodium (SNAC), sodium caprylate (C8), and sodium caprate (C10), is generally resulting in relatively low oral bioavailabilities (BAs)-even for carefully selected therapeutics. With several hundred peptide-based drugs presently in the pipeline, there is a huge unmet need for more effective PEs. Aiming to provide useful insights for the development of novel PEs, this review summarizes the biological hurdles to oral peptide delivery with special emphasis on the epithelial barrier. It describes the concepts and action modes of PEs and mentions possible new targets. It further states the benchmark that is set by current PEs, while critically assessing and evaluating emerging PEs regarding translatability, safety, and efficacy. Additionally, examples of novel PEs under preclinical and clinical evaluation and future directions are discussed.
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Affiliation(s)
- Marilena Bohley
- Institute of Pharmaceutical SciencesDepartment of Chemistry and Applied BiosciencesETH ZurichZurich8093Switzerland
| | - Jean‐Christophe Leroux
- Institute of Pharmaceutical SciencesDepartment of Chemistry and Applied BiosciencesETH ZurichZurich8093Switzerland
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Argüeso P. Human ocular mucins: The endowed guardians of sight. Adv Drug Deliv Rev 2022; 180:114074. [PMID: 34875287 PMCID: PMC8724396 DOI: 10.1016/j.addr.2021.114074] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 10/22/2021] [Accepted: 11/30/2021] [Indexed: 01/03/2023]
Abstract
Mucins are an ancient group of glycoproteins that provide viscoelastic, lubricating and hydration properties to fluids bathing wet surfaced epithelia. They are involved in the protection of underlying tissues by forming a barrier with selective permeability properties. The expression, processing and spatial distribution of mucins are often determined by organ-specific requirements that in the eye involve protecting against environmental insult while allowing the passage of light. The human ocular surface epithelia have evolved to produce an extremely thin and watery tear film containing a distinct soluble mucin product secreted by goblet cells outside the visual axis. The adaptation to the ocular environment is notably evidenced by the significant contribution of transmembrane mucins to the tear film, where they can occupy up to one-quarter of its total thickness. This article reviews the tissue-specific properties of human ocular mucins, methods of isolation and detection, and current approaches to model mucin systems recapitulating the human ocular surface mucosa. This knowledge forms the fundamental basis to develop applications with a promising biological and clinical impact.
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Affiliation(s)
- Pablo Argüeso
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, United States.
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Lin YJ, Shatkin JA, Kong F. Evaluating mucoadhesion properties of three types of nanocellulose in the gastrointestinal tract in vitro and ex vivo. Carbohydr Polym 2019; 210:157-166. [DOI: 10.1016/j.carbpol.2019.01.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 01/09/2019] [Accepted: 01/09/2019] [Indexed: 02/05/2023]
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Analysis of Extracellular Vesicles in Gastric Juice from Gastric Cancer Patients. Int J Mol Sci 2019; 20:ijms20040953. [PMID: 30813244 PMCID: PMC6412909 DOI: 10.3390/ijms20040953] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 02/17/2019] [Accepted: 02/20/2019] [Indexed: 12/19/2022] Open
Abstract
Extracellular vesicles (EVs) are secretory membrane vesicles containing lipids, proteins, and nucleic acids; they function in intercellular transport by delivering their components to recipient cells. EVs are observed in various body fluids, i.e., blood, saliva, urine, amniotic fluid, and ascites. EVs secreted from cancer cells play important roles in the formation of their environment, including fibrosis, angiogenesis, evasion of immune surveillance, and even metastasis. However, EVs in gastric juice (GJ-EVs) have been largely unexplored. In this study, we sought to clarify the existence of GJ-EVs derived from gastric cancer patients. GJ-EVs were isolated by the ultracentrifuge method combined with our own preprocessing from gastric cancer (GC) patients. We verified GJ-EVs by morphological experiments, i.e., nanoparticle tracking system analysis and electron microscopy. In addition, protein and microRNA markers of EVs were examined by Western blotting analysis, Bioanalyzer, or quantitative reverse transcription polymerase chain reaction. GJ-EVs were found to promote the proliferation of normal fibroblast cells. Our findings suggest that isolates from the GJ of GC patients contain EVs and imply that GJ-EVs partially affect their microenvironments and that analysis using GJ-EVs from GC patients will help to clarify the pathophysiology of GC.
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Dutton JS, Hinman SS, Kim R, Wang Y, Allbritton NL. Primary Cell-Derived Intestinal Models: Recapitulating Physiology. Trends Biotechnol 2018; 37:744-760. [PMID: 30591184 DOI: 10.1016/j.tibtech.2018.12.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 12/02/2018] [Accepted: 12/03/2018] [Indexed: 02/07/2023]
Abstract
The development of physiologically relevant intestinal models fueled by breakthroughs in primary cell-culture methods has enabled successful recapitulation of key features of intestinal physiology. These advances, paired with engineering methods, for example incorporating chemical gradients or physical forces across the tissues, have yielded ever more sophisticated systems that enhance our understanding of the impact of the host microbiome on human physiology as well as on the genesis of intestinal diseases such as inflammatory bowel disease and colon cancer. In this review we highlight recent advances in the development and usage of primary cell-derived intestinal models incorporating monolayers, organoids, microengineered platforms, and macrostructured systems, and discuss the expected directions of the field.
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Affiliation(s)
- Johanna S Dutton
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, and North Carolina State University, Raleigh, NC, USA
| | - Samuel S Hinman
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, USA
| | - Raehyun Kim
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, and North Carolina State University, Raleigh, NC, USA
| | - Yuli Wang
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, USA
| | - Nancy L Allbritton
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, and North Carolina State University, Raleigh, NC, USA; Department of Chemistry, University of North Carolina, Chapel Hill, NC, USA.
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García-Díaz M, Birch D, Wan F, Nielsen HM. The role of mucus as an invisible cloak to transepithelial drug delivery by nanoparticles. Adv Drug Deliv Rev 2018; 124:107-124. [PMID: 29117511 DOI: 10.1016/j.addr.2017.11.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/03/2017] [Accepted: 11/01/2017] [Indexed: 01/05/2023]
Abstract
Mucosal administration of drugs and drug delivery systems has gained increasing interest. However, nanoparticles intended to protect and deliver drugs to epithelial surfaces require transport through the surface-lining mucus. Translation from bench to bedside is particularly challenging for mucosal administration since a variety of parameters will influence the specific barrier properties of the mucus including the luminal fluids, the microbiota, the mucus composition and clearance rate, and the condition of the underlying epithelia. Besides, after administration, nanoparticles interact with the mucosal components, forming a biomolecular corona that modulates their behavior and fate after mucosal administration. These interactions are greatly influenced by the nanoparticle properties, and therefore different designs and surface-engineering strategies have been proposed. Overall, it is essential to evaluate these biomolecule-nanoparticle interactions by complementary techniques using complex and relevant mucus barrier matrices.
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Affiliation(s)
- María García-Díaz
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028 Barcelona, Spain
| | - Ditlev Birch
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Feng Wan
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Hanne Mørck Nielsen
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.
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Bakli C, Chakraborty S. Rapid capillary filling via ion-water interactions over the nanoscale. NANOSCALE 2016; 8:6535-6541. [PMID: 26935707 DOI: 10.1039/c5nr08704j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Giant frictional resistances are grand challenges against the rapid filling of nanoscale capillaries, as encountered in a wide variety of applications ranging from nature to energy. It is commonly believed that partially wettable charged nanocapillaries fill up considerably slower, compared to completely wettable ones, under the influence of a complex interplay between interfacial tension and electrical interactions. In sharp contrast to this common belief, here we discover a new non-intuitive regime of rapid filling of charged capillaries over the nanometer scale, by virtue of which a partially wettable capillary may fill up comparatively faster than a completely wettable one. We attribute the fundamental origin of this remarkable behavior to ion-water interactions over interfacial scales. The underlying novel electro-hydrodynamic mechanism, as unveiled here, may provide deeper insights into the physico-chemical interactions leading to augmentations in the rates of nanocapillary filling over hydrophobic regimes, bearing far-reaching implications in the transport of biological fluids, enhanced oil recovery, and miniaturized energy harvesting applications.
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Affiliation(s)
- Chirodeep Bakli
- Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur, Kharagpur 721302, India.
| | - Suman Chakraborty
- Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur, Kharagpur 721302, India.
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Wexler JS, Jacobi I, Stone HA. Shear-driven failure of liquid-infused surfaces. PHYSICAL REVIEW LETTERS 2015; 114:168301. [PMID: 25955076 DOI: 10.1103/physrevlett.114.168301] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Indexed: 05/15/2023]
Abstract
Rough or patterned surfaces infused with a lubricating liquid display many of the same useful properties as conventional gas-cushioned superhydrophobic surfaces. However, liquid-infused surfaces exhibit a new failure mode: the infused liquid film may drain due to an external shear flow, causing the surface to lose its advantageous properties. We examine shear-driven drainage of liquid-infused surfaces with the goal of understanding and thereby mitigating this failure mode. On patterned surfaces exposed to a known shear stress, we find that a finite length of the surface remains wetted indefinitely, despite the fact that no physical barriers prevent drainage. We develop an analytical model to explain our experimental results, and find that the steady-state retention results from the ability of patterned surfaces to wick wetting liquids, and is thus analogous to capillary rise. We establish the geometric surface parameters governing fluid retention and show how these parameters can describe even random substrate patterns.
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Affiliation(s)
- Jason S Wexler
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Ian Jacobi
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA
- Faculty of Aerospace Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, USA
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Miyauchi M, Hayashida M, Yokota H. Evaluation of residual toxic substances in the stomach using upper gastrointestinal endoscopy for management of patients with oral drug overdose on admission: a prospective, observational study. Medicine (Baltimore) 2015; 94:e463. [PMID: 25634188 PMCID: PMC4602959 DOI: 10.1097/md.0000000000000463] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The guidelines on the indications for gastric lavage were published in 1997, and a less-aggressive initial approach has been used for poisoned patients. Clinical studies have shown that the outcomes of retrieval of residual toxic substances in the stomach are variable and that no beneficial effect is obtained. However, the presence of residual toxic substances in the stomach before gastric lavage has not been estimated. The objective of this study was to evaluate the residual stomach contents on admission of patients with oral drug overdoses using upper gastrointestinal endoscopy. A 2-year prospective study of 167 patients with oral drug overdoses was performed. Endoscopy was performed on admission to observe the gastric body, fornix, and pyloric antrum. Patients were classified into 3 groups according to the digestive phase (tablet/food phase, soluble/fluid phase, and reticular/empty phase). The groups were compared with respect to time elapsed since ingestion, and numbers and variety of orally overdosed drugs. The numbers of patients in each phase were as follows: tablet/food phase, 73; soluble/fluid phase, 50; and reticular/empty phase, 44. The tablet/food and soluble/fluid phase groups contained the greatest numbers of patients who presented within 1 to 2 hours since ingestion. In the tablet/food group, only 12 of 73 patients (16%) presented within 1 hour since ingestion, and 3 patients presented >12 hours since ingestion. In the soluble/fluid phase group, only 9 of 50 patients (18%) presented within 1 hour since ingestion, and 2 patients presented >12 hours since ingestion. The reticular/empty phase group contained the greatest number of patients presenting within 2 to 4 hours since ingestion, and 3 patients presented within 1 hour since ingestion. The residual stomach contents before lavage were variable in all of the groups. The residual gastric content before the performance of gastric lavage is variable in overdosed patients on admission. This may influence the efficiency of gastric lavage with respect to retrieval of residual toxic substances in the stomach. This study may contribute to the development of a strategy for treating patients who have orally overdosed on drugs in the future.
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Affiliation(s)
- Masato Miyauchi
- From the Department of Emergency and Critical Care Medicine (MM, HY); and Department of Legal Medicine (MH), Nippon Medical School, Tokyo, Japan
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Abstract
OBJECTIVE To review and summarize the human and veterinary literature regarding stress-related mucosal disease (SRMD) pathogenesis, patient risk factors, and therapeutic options for prophylaxis and treatment. ETIOLOGY SRMD is a common sequela of critical illness in human patients. Development of SRMD results from splanchnic hypoperfusion, reperfusion injury, and exposure of the gastric mucosa to acid, pepsin, and bile acids following breakdown of the gastric mucosal defense system. Human patients with the highest risk of stress ulceration include those with respiratory failure necessitating mechanical ventilation greater than 48 h or coagulopathy. Currently, little is known about the incidence and pathophysiology of SRMD in critically ill veterinary patients. DIAGNOSIS A presumptive diagnosis can be made in high-risk patient populations following detection of occult or gross blood in nasogastric tube aspirates, hematemesis, or melena. Definitive diagnosis is achieved via esophagogastroduodenoscopy. Lesions are localized to the acid-producing portions of the stomach, the fundus, and body. THERAPY Therapy is aimed at optimization of tissue perfusion and oxygenation. Pharmacologic interventions are instituted to increase intraluminal pH and augment natural gastric defenses. Histamine(2)-receptor antagonists, proton pump inhibitors, and sucralfate are the mainstays of therapy. In people, clinically significant bleeding may necessitate additional interventions (eg, packed red blood cell transfusions, endoscopic, or surgical hemostasis). PROGNOSIS Mortality is increased in people with clinically significant bleeding compared to those patients who do not bleed. Institution of prophylaxis is recommended in high-risk patients. However, no consensus exists regarding initiation of prophylaxis, preference of frontline drug class, or indication for discontinuation of therapy. The prognosis of veterinary patients with SRMD remains unknown at this time.
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Affiliation(s)
- Andrea A Monnig
- Department of Emergency and Critical Care, The Animal Medical Center, New York, NY 10065, USA.
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Varum FJO, Veiga F, Sousa JS, Basit AW. Mucus thickness in the gastrointestinal tract of laboratory animals. ACTA ACUST UNITED AC 2011; 64:218-27. [PMID: 22221097 DOI: 10.1111/j.2042-7158.2011.01399.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVES The objective of this study was to systematically assess the mucus thickness in the gastrointestinal tract of laboratory animals commonly used in preclinical studies. METHODS Mucus thickness was studied post-mortem in the rat, rabbit and pig, using cryosections stained by the modified periodic acid Schiff/Alcian blue method. KEY FINDINGS The mucus thickness in the fundus region of the stomach was higher in the pig (190.7 ± 80.7 µm) than in the rabbit (155.1 ± 85.8 µm) and the rat (31.3 ± 11.4 µm). However, along the small intestine (ileum), mucus was thicker in the rabbit (147.8 ± 115.6 µm), followed by the pig (53.8 ± 22.1 µm) and the rat (34.1 ± 14.9 µm). This rank order was also observed in the ascending colon. CONCLUSIONS Inter-species variability in mucus thickness along the gut was demonstrated and suggests that the pig resembles more closely the mucus pattern of humans. This may be highly relevant when preclinical animal models are used in drug absorption studies or in the development of oral mucoadhesive drug delivery systems.
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Affiliation(s)
- Felipe J O Varum
- Center for Pharmaceutical Studies, Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal The School of Pharmacy, University of London, London, UK
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Perforation of peptic ulcer following abrupt cessation of long-term opiate use. Surg Today 2010; 40:836-9. [PMID: 20740346 DOI: 10.1007/s00595-009-4147-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 08/06/2009] [Indexed: 10/19/2022]
Abstract
PURPOSE Unaided and abrupt cessation of opiate use without drug substitution and step-down, referred to as "cold turkey," is a common and difficult process for substance users, and is associated with several withdrawal symptoms and complications. This report presents a preliminary series of patients treated at an urban public hospital with acute perforation of peptic ulcers following abrupt cessation of long-term opiate use, a phenomenon that has not been previously described in the literature. METHODS Thirty-five patients with acute gastroduodenal perforation and a history of opiate addiction with a recent and abrupt cessation of opiate use were admitted between February 2004 and October 2008. This study evaluated the demographics, antecedent drug use, substance use characteristics, previous medical or surgical treatment of peptic ulcer disease, and surgical findings. RESULTS The mean age was 32.3 years (range, 21-41 years) and the patients were overwhelmingly male (94%). The most frequent agent in single opiate users was opium (62.9%) followed by heroin (22.9%). The time interval between opiate cessation and perforation onset was 2-65 days (mean, 6.1 days). All patients underwent an immediate exploratory laparotomy, and the majority of perforations were found to be in the postpyloric area (94%) with mean size of 4.3 x 5.1 mm. Two patients (6%) had perforations in the lesser curvature of the stomach. CONCLUSION All of the perforations occurred following sudden self-cessation without step-down or classic maintenance therapy, and this may prove the importance of supervised medical detoxification with special attention to gastroprotective agents such as antacid drugs.
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Varum FJ, Veiga F, Sousa JS, Basit AW. An investigation into the role of mucus thickness on mucoadhesion in the gastrointestinal tract of pig. Eur J Pharm Sci 2010; 40:335-41. [DOI: 10.1016/j.ejps.2010.04.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 04/13/2010] [Accepted: 04/14/2010] [Indexed: 12/16/2022]
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Liman N, Alan E, Küçük Bayram G. The differences between the localizations of MUC1, MUC5AC, MUC6 and osteopontin in quail proventriculus and gizzard may be a reflection of functional differences of stomach parts. J Anat 2010; 217:57-66. [PMID: 20492430 PMCID: PMC2913012 DOI: 10.1111/j.1469-7580.2010.01243.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/10/2010] [Indexed: 11/30/2022] Open
Abstract
Mucins are high molecular weight glycoproteins which constitute the major component of the mucus layer and are produce by many epithelial tissues in vertebrates. Osteopontin (OPN) is an adhesive phosphorylated glycoprotein that is expressed by a broad range of tissues and cells. Although gastric mucins MUC1, MUC5AC, MUC6 and OPN have been widely used in histological studies and in diagnostic pathology in order to diagnose gastric carcinomas, their localizations in the stomach of quail have not yet been studied. In this study, the localizations of MUC1, MUC5AC, MUC6 and OPN in the proventriculus and gizzard of Japanese quail during the post-hatching period were compared at light microscope levels by applying immunohistochemical methods. In all ages studied, the immunoreactivity of MUC5AC was present in the lining epithelium of both folds and superficial proventricular glands in the proventriculus, whereas MUC1, MUC6 and OPN reactivity was found in the oxynticopeptic cells of profound proventricular glands. In addition, some cells in the fold epithelium of the proventriculus showed a positive reaction to OPN. The immunoreactivity of MUC1 in gizzard was different from that of MUC5AC. Although MUC5AC was expressed in the cells of both the surface epithelium and profound glands of the gizzard, MUC1 was only localized in the profound glands of the gizzard. However, MUC6 and OPN immunoreactivity was absent in the gizzard. The results indicated that the differences between the localizations of MUC1, MUC5AC, MUC6 and OPN in quail proventriculus and gizzard may be a reflection of functional differences of stomach parts. Although the biological significances of the expressions of MUC1, MUC5AC, MUC6 and OPN in the quail stomach remains unknown, these notable glycoproteins may be associated with barrier function, host defence, and/or secretion.
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Affiliation(s)
- Narin Liman
- Department of Histology and Embryology, Faculty of Veterinary Medicine, University of Erciyes, Kayseri, Turkey.
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Thompson B, Sharp P, Elliott R, Al-Mutairi S, Fairweather-Tait SJ. Development of a modified Caco-2 cell model system for studying iron availability in eggs. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:3833-3839. [PMID: 20170171 DOI: 10.1021/jf904175d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A modified Caco-2 cell model system was developed for studying iron availability in mixtures of fresh and/or cooked foods subjected to a simulated gastrointestinal digestion. The effect of combining foods containing high levels of ascorbic acid with cooked eggs on ferritin expression in the cells was measured. There was no detectable increase in ferritin with eggs alone, indicating that none of the iron was available for uptake into the cells, but when mixed with orange juice or salad (lettuce, tomatoes, and red pepper) in ratios similar to those found in meals, there was a significant increase in ferritin concentration (p = 0.0012 and p = 9.2 x 10(-10), respectively); the enhancing effect of salad was greater than orange juice (p = 0.028). These results suggest that the iron in eggs will be more readily absorbed when consumed with foods high in ascorbic acid.
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Affiliation(s)
- Ben Thompson
- School of Medicine, University of East Anglia, Norwich, United Kingdom
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O'Gara EA, Maslin DJ, Nevill AM, Hill DJ. The effect of simulated gastric environments on the anti-Helicobacter activity of garlic oil. J Appl Microbiol 2007; 104:1324-31. [PMID: 18028365 DOI: 10.1111/j.1365-2672.2007.03637.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
AIMS To investigate the effects of simulated gastric conditions upon the anti-Helicobacter pylori effects of garlic oil (GO). METHODS AND RESULTS Time course viability experiments assessed the anti-H. pylori activity of GO (16 and 32 microg ml(-1)) in simulated gastric environments. Rapid anti-H. pylori action of GO was observed in artificial gastric juice. Mucus (1-5%) was strongly protective of H. pylori both alone and in the presence of GO, but its protective effect was antagonized by GO. Peptone (5-15 g l(-1)) caused a dose-dependent reduction in the anti-H. pylori activity of GO. Rapeseed oil (5.7-17 g l(-1)) greatly diminished the anti-H. pylori activity of GO. Dextrin (44 and 133 g l(-1)) exhibited direct anti-H. pylori effects and added to those of GO. Simulated meal mixtures decreased but did not eliminate the anti-H. pylori activity of 32 mug ml(-1) GO. CONCLUSIONS The anti-H. pylori activity of GO was noticeably affected by food materials and mucin. However, substantial activity remained under simulated gastric conditions. Further investigation of the therapeutic potential of GO against H. pylori is therefore warranted. SIGNIFICANCE AND IMPACT OF THE STUDY Garlic oil may be useful as an alternative treatment against H. pylori, a major cause of gastrointestinal infections in humans.
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Affiliation(s)
- E A O'Gara
- Research Institute in Healthcare Science, University of Wolverhampton, School of Applied Sciences, Wolverhampton, United Kingdom.
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Jin F, Welch R, Glahn R. Moving toward a more physiological model: application of mucin to refine the in vitro digestion/Caco-2 cell culture system. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2006; 54:8962-7. [PMID: 17090148 DOI: 10.1021/jf061684i] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The objective of this study was to determine if a combination of commercially available mucin and an 8 microm microporous membrane insert can be used to replace the 15 kDa molecular weight cutoff (MWCO) dialysis membrane used in an established in vitro digestion/Caco-2 cell culture system. Although the current model with the 15 kDa membrane correlates well with human studies, use of mucin may improve the system as the mucus layer is suspected to play a physiological role in Fe absorption. Use of mucin may also enable more complete assessment of iron bioavailability from large molecular weight forms of Fe such as heme and ferritin Fe. A range of foods or Fe (i.e., FeCl(3) +/- ascorbic acid, cooked beef, red bean, white bean, soybean, horse spleen ferritin and plant-type ferritin) were subjected to in vitro digestion. In the presence of mucin, significantly more Fe was taken up from the heme Fe (86%) and ferritin (91%) samples and significantly less Fe was taken up from the white bean samples ( approximately 70%) relative to the 15 kDa membrane. The results indicated that the forms of iron interact with mucin. The mucus layer has a significant effect on Fe uptake. Further refinement and characterization of the mucin method is needed before it can be deemed to be a suitable replacement for the dialysis membrane.
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Affiliation(s)
- Fuxia Jin
- U.S. Plant, Soil and Nutrition Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Tower Road, Ithaca, New York 14853, USA
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Kubota S, Yamauchi K, Kumagai T, Sugano M, Kawasaki K, Tozuka M, Akamatsu T, Matsuzawa K, Sugiyama A, Kurihara M, Katsuyama T, Ota H. Quantitative determination of gland mucous cells-type mucin using a monoclonal antibody, HIK1083: its pathophysiological changes in human gastric juice. Clin Chim Acta 2006; 377:261-7. [PMID: 17134689 DOI: 10.1016/j.cca.2006.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 10/04/2006] [Accepted: 10/13/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND Pathological alteration in gastric mucosa is caused by Helicobacter pylori infection and is detectable by histological analysis. In particular, the alteration of gland mucous cells (GMCs)-type mucin, which plays a protective role against H. pylori infection, is critical in the pathogenesis of H. pylori-related gastritis. We established an assay for GMCs-type mucin and quantitatively assessed the pathophysiological changes in its content in human gastric juice samples. METHODS The assay method for GMCs-type mucin was based on ELISA using a monoclonal antibody (HIK1083), and was used it to measure GMCs-type mucin in gastric juice obtained from patients with or without H. pylori infection. RESULTS All the basic characteristics of the current method were satisfactory to quantify the GMCs-type mucin content in gastric juice. The GMCs-type mucin content, but not total mucin content, was significantly higher in patients with H. pylori infection (n=17; 437+/-476 U, mean+/-SD) than in those without H. pylori infection (n=55; 168+/-322 U, p<0.05). CONCLUSIONS The current method is suitable for the quantitative analysis of GMCs-type mucin in gastric juice. The change in GMCs-type mucin content in gastric juice may be possibly implicated in the pathophysiology of the gastric mucosa and in the patient's gastric mucosal lesions.
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Affiliation(s)
- Seiko Kubota
- Department of Laboratory Medicine, Shinshu University Hospital, 3-1-1 Asahi, Matsumoto 390-8621, Japan
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Pynaert I, Armah C, Fairweather-Tait S, Kolsteren P, van Camp J, De Henauw S. Iron solubility compared with in vitro digestion-Caco-2 cell culture method for the assessment of iron bioavailability in a processed and unprocessed complementary food for Tanzanian infants (6-12 months). Br J Nutr 2006; 95:721-6. [PMID: 16571151 DOI: 10.1079/bjn20051722] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The Fe solubility test is a commonly used, easy and relatively cheap in vitro tool for predicting Fe bioavailability in food matrices. However, the outcome of a recent field trial comparing the effect on Fe status of Tanzanian infants of processed v. unprocessed complementary foods (CF), with otherwise the same composition, challenged the validity of this test for predicting Fe bioavailability. In the solubility test, significant more soluble Fe was observed in processed compared with unprocessed foods (mean 18.8 (sem 0.21) v. 4.8 (sem 0.23) %; P<0.001). However, in the field trial, no significant difference in Fe status was seen between processed and unprocessed CF groups after 6 months' follow-up. Therefore, twenty-four samples of these CF (twelve processed and twelve unprocessed batches) were analysed in triplicate for Fe availability using an in vitro digestion-Caco-2 cell culture method and results were compared with solubility results. Significantly more soluble Fe was presented to Caco-2 cells in the processed compared with unprocessed samples (mean 11.5 (sem 1.16) v. 8.5 (sem 2.54) %; P=0.028), but proportionally less Fe was taken up by the cells (mean 3.0 (sem 0.40) v. 11.7 (sem 2.22) %; P=0.007). As a net result, absolute Fe uptake was lower (not significantly) in processed compared with unprocessed CF (mean 1.3 (sem 0.16) v. 3.4 (sem 0.83) nmol/mg cell protein; P=0.052). These data clearly demonstrate that the Fe solubility test was not a good indicator of Fe bioavailability in these particular food matrices. In contrast, the results of an in vitro Caco-2 model supported the effects observed in vivo.
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Affiliation(s)
- Ilse Pynaert
- Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK.
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21
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Allen A, Flemström G. Gastroduodenal mucus bicarbonate barrier: protection against acid and pepsin. Am J Physiol Cell Physiol 2005; 288:C1-19. [PMID: 15591243 DOI: 10.1152/ajpcell.00102.2004] [Citation(s) in RCA: 378] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Secretion of bicarbonate into the adherent layer of mucus gel creates a pH gradient with a near-neutral pH at the epithelial surfaces in stomach and duodenum, providing the first line of mucosal protection against luminal acid. The continuous adherent mucus layer is also a barrier to luminal pepsin, thereby protecting the underlying mucosa from proteolytic digestion. In this article we review the present state of the gastroduodenal mucus bicarbonate barrier two decades after the first supporting experimental evidence appeared. The primary function of the adherent mucus gel layer is a structural one to create a stable, unstirred layer to support surface neutralization of acid and act as a protective physical barrier against luminal pepsin. Therefore, the emphasis on mucus in this review is on the form and role of the adherent mucus gel layer. The primary function of the mucosal bicarbonate secretion is to neutralize acid diffusing into the mucus gel layer and to be quantitatively sufficient to maintain a near-neutral pH at the mucus-mucosal surface interface. The emphasis on mucosal bicarbonate in this review is on the mechanisms and control of its secretion and the establishment of a surface pH gradient. Evidence suggests that under normal physiological conditions, the mucus bicarbonate barrier is sufficient for protection of the gastric mucosa against acid and pepsin and is even more so for the duodenum.
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Affiliation(s)
- Adrian Allen
- Physiological Sciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom
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22
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Ramirez FC, Holland JF, Harker J, Leung FW. Effect of acid on duodenal blood flow and mucus secretion measured by reflectance spectrophotometry: a prospective, randomized-controlled study. Aliment Pharmacol Ther 2004; 20:517-25. [PMID: 15339323 DOI: 10.1111/j.1365-2036.2004.02122.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND In animals, hydrochloric acid increases blood flow and mucus secretion in the duodenal mucosa. A significant correlation between index of haemoglobin oxygen saturation and mucosal blood flow, and between change in index of haemoglobin concentration and mucus thickness, respectively, has been demonstrated by reflectance spectrophotometry. AIM To examine the effect of topical hydrochloric acid upon mucosal blood flow and mucus secretion in the human duodenum. METHODS This prospective study of 120 patients undergoing routine upper endoscopy, examined the effect of topical 0.1 n hydrochloric acid or 0.9% saline on the duodenal bulb in a randomized, double-blind fashion. Duodenal mucosal index of haemoglobin oxygen saturation and index of haemoglobin concentration were measured by endoscopic reflectance spectrophotometry before and after hydrochloric acid or saline. RESULTS Baseline index of haemoglobin oxygen saturation, calculated blood flow and index of haemoglobin concentration measurements were comparable between hydrochloric acid (n = 60) and saline (n = 60) treated groups. A history of current use of non-steroidal anti-inflammatory drug was associated with a significantly lower baseline index of haemoglobin oxygen saturation and calculated blood flow. Hydrochloric acid resulted in a significant increase in index of haemoglobin oxygen saturation and calculated blood flow, but a decrease in index of haemoglobin concentration, reflecting an increase in mucus thickness compared with saline. CONCLUSIONS Our observations in humans confirm data in animal studies that topical exposure to hydrochloric acid induces an increase in duodenal mucosal blood flow and mucus secretion. Post hoc analysis of the data also revealed that attenuation of basal duodenal mucosal blood flow is associated with a history of current non-steroidal anti-inflammatory drug use. Endoscopic reflectance spectrophotometry appears to be adequate to assess factors that influence duodenal defence mechanisms of blood flow and mucus secretion in humans.
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Affiliation(s)
- F C Ramirez
- Research and Medical Services, Carl T. Hayden VA Medical Center, Phoenix, AZ 85012, USA.
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23
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Ward DM, Leib MS, Johnston SA, Marini M. The effect of dosing interval on the efficacy of misoprostol in the prevention of aspirin-induced gastric injury. J Vet Intern Med 2003; 17:282-90. [PMID: 12774967 DOI: 10.1111/j.1939-1676.2003.tb02449.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The effect of twice-daily administration of misoprostol on aspirin-induced gastric injury was evaluated. Twenty-four random-source dogs were divided into groups that received aspirin and misoprostol as follows: group I, aspirin 25 mg/kg PO q8h and placebo PO q8h; group II, aspirin 25 mg/kg PO q8h and misoprostol 3 microg/kg PO q8h; group III, aspirin 25 mg/kg PO q8h, misoprostol 3 microg/kg PO q12h, and placebo PO q24h; and group IV, aspirin 25 mg/kg PO q8h, misoprostol 3 microg/kg PO q24h, and placebo PO q12h for 28 days. Gastroscopy was performed on days -9, 5, 14, and 28. Visible lesions were scored on a scale of 1 (mucosal hemorrhage) to 11 (perforating ulcer). No difference in total score was identified between groups I and IV on any day. Median total scores for groups II and III were significantly (P < or = .05) lower compared to groups I and IV on day 5. Group III had a significantly lower score (P < or = .05) than groups I, II, and IV on day 28. This study suggests that misoprostol 3 microg/kg PO q12h is as effective as misoprostol 3 microg/kg PO q8h in preventing aspirin-induced gastric injury in this model. However, misoprostol 3 microg/ kg PO q8h was less effective in preventing aspirin-induced gastric injury on days 14 and 28 than in previous studies. No difference among numbers of dog-days of vomiting, diarrhea, or anorexia was detected among groups.
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Affiliation(s)
- Deborah M Ward
- Department of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
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24
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Cho CH, Wu KK, Wu S, Wong TM, So WHL, Liu ESL, Chu KM, Shin VY, Ye YN, Wong BCY. Morphine as a drug for stress ulcer prevention and healing in the stomach. Eur J Pharmacol 2003; 460:177-82. [PMID: 12559379 DOI: 10.1016/s0014-2999(02)02922-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Morphine pretreatment protects against stress-induced gastric ulceration, however, the exact mechanism is still undefined. Interestingly, the effect of morphine on ulcer healing has not been investigated. In this report, we would like to study these effects in a defined stress ulcer model and to delineate a new implication for morphine to promote stress ulcer healing in rats. Our study showed that cold-restraint stress for 3 h induced hemorrhagic lesions and increased myeloperoxidase activity in the gastric mucosa. Stress also reduced the dimension of layer of periodic acid-Schiff reagent-stained cells in the gastric mucosa by about 50%. Morphine pretreatment (2 or 8 mg/kg, given intraperitoneally) at the time of stress dose-dependently reversed stress-induced gastric ulceration, increase of myeloperoxidase activity and reduction of thickness of mucus-stained cells in the gastric mucosa. Morphine treatment after stress (given at the end of a 3-h stress and also at 3 h thereafter) increased ulcer healing by reducing the ulcer size measured 24 h later. Such action was blocked by naloxone (8 mg/kg) given intraperitoneally 15 min before morphine treatment. Morphine also increased the number of cell proliferation and dimension of layer of cells stained for mucus but not the number of microvessels in the gastric mucosa. Moreover, the number of apoptotic cells was less evidenced in the morphine-treated rats. This study reports for the first time that morphine not only prevents stress ulceration but also promotes healing of stress ulcer through a defined mechanism.
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Affiliation(s)
- Chi H Cho
- Department of Pharmacology, Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, China.
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25
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Lindén S, Nordman H, Hedenbro J, Hurtig M, Borén T, Carlstedt I. Strain- and blood group-dependent binding of Helicobacter pylori to human gastric MUC5AC glycoforms. Gastroenterology 2002; 123:1923-30. [PMID: 12454849 DOI: 10.1053/gast.2002.37076] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND & AIMS In the stomach, Helicobacter pylori is found both in the mucus layer and adhering to the gastric epithelium. The aim of this study is to characterize the binding of H. pylori to human gastric mucins. METHODS H. pylori strains that bind the Lewis(b) (Le(b)) structure (via the BabA adhesin) and/or sialylated structures, along with isogenic adhesion deletion mutants, were used to identify microbe-binding mucins. Gastric mucins from 5 healthy individuals, isolated by density-gradient centrifugation, were investigated for H. pylori binding at neutral pH using a microtiter-based technique. RESULTS H. pylori strains that express the BabA adhesins were shown to bind to the MUC5AC mucin in individuals expressing the Le(b) antigen. Further fractionation with an ion-exchange chromatography revealed Le(b)-positive MUC5AC glycoforms that differed in their receptor properties for different H. pylori strains. None of the H. pylori strains studied bound to mucins from Le(b)-negative individuals. However, all strains bound to low-density, nonmucin, Le(b)-negative material on top of the gradients. CONCLUSIONS Binding of H. pylori to human gastric MUC5AC isolated from healthy individuals is BabA dependent and mediated by the Le(b) structure presented by the mucin. However, the BabA adhesins demonstrate strain-dependent preference in binding to MUC5AC glycoforms substituted with Le(b), allowing for great interindividual variability in host-microbe interactions.
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Affiliation(s)
- Sara Lindén
- Mucosal Biology Group, Department of Cell and Molecular Biology, Lund University, Sweden
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26
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Faure M, Moënnoz D, Montigon F, Fay LB, Breuillé D, Finot PA, Ballèvre O, Boza J. Development of a rapid and convenient method to purify mucins and determine their in vivo synthesis rate in rats. Anal Biochem 2002; 307:244-51. [PMID: 12202240 DOI: 10.1016/s0003-2697(02)00048-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The intestinal mucoprotein synthesis rate was measured in vivo for the first time. For this, a rapid, reproducible, and convenient method to purify mucoproteins from large numbers of intestinal samples at the same time was developed. The method takes advantage of both the high mucin resistance to protease activities due to their extensive glycosylations and the high mucin molecular size. Intestinal homogenates were partially digested with Flavourzyme. Nonprotected proteins partially degraded were easily separated from mucoproteins by small gel filtration chromatography using Sepharose CL-4B. Electrophoretically pure mucins were obtained. Their amino acid composition was typical of purified intestinal epithelial mucins. The mucoprotein synthesis rate was determined in vivo in rats using the flooding dose method with the stable isotope L-[1-13C]valine. Free L-[1-13C]valine enrichments in the intracellular pool were determined by GC-MS. L-[1-13C]valine enrichments into purified mucoproteins or intestinal mucosal proteins were measured by gas chromatography-combustion-isotope ratio mass spectrometry. In rats, we found that the gut mucosa protein synthesis rate (%/day) decreased regularly from duodenum (122%/day) to colon (43%/day). In contrast, mucoprotein fractional synthesis rates were in the same range along the digestive tract, between 112%/day (colon) and 138%/day (ileum).
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Affiliation(s)
- Magali Faure
- Nestlé Research Center, Nutrition Department, Nestec Ltd., Vers-chez-les-Blanc, Lausanne, Switzerland.
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27
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Mall AS, Dent DM, McLeod H, Kahn D, Taylor K, Hickman R. Extraction, isolation, and SDS-PAGE analysis of purified gastric mucin in a patient with Menetrier's disease. Am J Gastroenterol 2002; 97:752-5. [PMID: 11922574 DOI: 10.1111/j.1572-0241.2002.05560.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Menetrier's disease is a rare condition characterized by marked proliferation of gastric mucosa with variable mucus secretion and achlorhydria. Although crude mucus secretion and gastric aspirates have been evaluated in this disease for output of dry matter, hexosamine, fucose, protein content, and transforming growth factor alpha activity, we report for the first time the isolation, purification, and gel electrophoresis of mucin from crude mucus scrapings. The fragmentation pattern of mucin in Menetrier's disease demonstrated less large polymeric mucin than the control. There was also a band of approximately 55-65 kd M, on polyacrylamide gel electrophoresis similar to that found in gastric carcinoma or peptic ulcer, but absent in the control specimens.
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Affiliation(s)
- Anwar S Mall
- Department of Surgery, University of Cape Town, South Africa
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28
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Kang B, Alderman BM, Nicoll AJ, Cook GA, Giraud AS. Effect of omeprazole-induced achlorhydria on trefoil peptide expression in the rat stomach. J Gastroenterol Hepatol 2001; 16:1222-7. [PMID: 11903739 DOI: 10.1046/j.1440-1746.2001.02609.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Omeprazole is an inhibitor of the H+K+ ATPase of the gastric parietal cell, which is used clinically to suppress gastric acid secretion. It has also been found to inhibit gastric mucin production; however, its effects on the synthesis and secretion of the trefoil peptides, which are also expressed by mucus cells, and which play a key role in cytoprotection and epithelial repair, are unknown. METHODS Rats (n=8) were given either omeprazole (30 mg/kg per day; p.o.) or inert carrier for 1 week, and the effects on synthesis and peptide expression of the gastric trefoil peptides, TFF1/pS2 and TFF2/SP, were compared. RESULTS As expected, omeprazole treatment abolished H+ ion production with a mean gastric juice pH of 7.2 compared with 2.4 for controls. The omeprazole group had elevated total protein levels of 35-fold and TFF1/pS2 peptide levels elevated fourfold, respectively, but not TFF2/SP peptide in gastric juice, suggesting that the increased pH reduced the viscosity of adherent mucus, thereby increasing gastric juice concentrations by dissolution of adherent TFF1/pS2 and increased secretion. Concomitant with increased TFF1/pS2 secretion was a fall in predominantly antral mucosal trefoil peptide concentrations. In contrast to trefoil secretory rates, the steady-state synthesis of both TFF1/pS2 and TFF2/SP was unchanged after omeprazole treatment, implying both a large cellular pool of processed peptide and rapid secretion. CONCLUSION The increase in the concentration of TFF1/pS2 in gastric secretions during chronic omeprazole-induced achlorhydria may be important in preventing tissue injury and promoting repair in response to an increased luminal bacterial population.
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Affiliation(s)
- B Kang
- Department of Medicine, University of Melbourne, Western Hospital, Footscray, Australia
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29
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Kawabata A, Kinoshita M, Nishikawa H, Kuroda R, Nishida M, Araki H, Arizono N, Oda Y, Kakehi K. The protease-activated receptor-2 agonist induces gastric mucus secretion and mucosal cytoprotection. J Clin Invest 2001; 107:1443-50. [PMID: 11390426 PMCID: PMC209315 DOI: 10.1172/jci10806] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2000] [Accepted: 05/01/2001] [Indexed: 01/12/2023] Open
Abstract
Protease-activated receptor-2 (PAR-2), a receptor activated by trypsin/tryptase, modulates smooth muscle tone and exocrine secretion in the salivary glands and pancreas. Given that PAR-2 is expressed throughout the gastrointestinal tract, we investigated effects of PAR-2 agonists on mucus secretion and gastric mucosal injury in the rat. PAR-2-activating peptides triggered secretion of mucus in the stomach, but not in the duodenum. This mucus secretion was abolished by pretreatment with capsaicin, which stimulates and ablates specific sensory neurons, but it was resistant to cyclo-oxygenase inhibition. In contrast, capsaicin treatment failed to block PAR-2-mediated secretion from the salivary glands. Intravenous calcitonin gene-related peptide (CGRP) and neurokinin A markedly elicited gastric mucus secretion, as did substance P to a lesser extent. Specific antagonists of the CGRP1 and NK2, but not the NK1, receptors inhibited PAR-2-mediated mucus secretion. Pretreatment with the PAR-2 agonist strongly prevented gastric injury caused by HCl-ethanol or indomethacin. Thus, PAR-2 activation triggers the cytoprotective secretion of gastric mucus by stimulating the release of CGRP and tachykinins from sensory neurons. In contrast, the PAR-2-mediated salivary exocrine secretion appears to be independent of capsaicin-sensitive sensory neurons.
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Affiliation(s)
- A Kawabata
- Faculty of Pharmaceutical Sciences, Kinki University, Higashi-Osaka, Japan.
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30
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Kinoshita M, Inagake K, Kawabata A, Kuroda R, Oda Y, Kakehi K. Fluorometric determination of mucin-type glycoproteins by the galactose oxidase-peroxidase method. Anal Biochem 2000; 284:87-92. [PMID: 10933860 DOI: 10.1006/abio.2000.4689] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We developed a convenient and specific method for the determination of mucin-type glycoproteins using galactose oxidase and horseradish peroxidase on the basis of the contents of galactosyl and N-acetylgalactosaminyl residues in glycoproteins. Galactose and galactosamine residues released from glycoproteins after hydrolysis were oxidized with galactose oxidase and subsequently the resultant hydrogen peroxide was determined by a combination of horseradish peroxidase and 3-(p-hydroxyphenyl) propionic acid as a fluorogenic substrate. The contents of galactose/galactosamine residues in N- and O-glycans, as determined by the galactose oxidase-peroxidase method, were in good agreement with those described in the previous reports. We applied the present method to determine mucin-type glycoproteins secreted from rat gastric mucosa by stimulation with misoprostol, a prostaglandin E(1) analogue in vivo. Thus, the galactose oxidase-peroxidase method is useful for the determination of mucin-type glycoproteins in biological materials.
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Affiliation(s)
- M Kinoshita
- Faculty of Pharmaceutical Sciences, Kinki University, Kowakae 3-4-1, Higashi-osaka 577-8502, Japan
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31
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Akiba Y, Guth PH, Engel E, Nastaskin I, Kaunitz JD. Dynamic regulation of mucus gel thickness in rat duodenum. Am J Physiol Gastrointest Liver Physiol 2000; 279:G437-47. [PMID: 10915654 DOI: 10.1152/ajpgi.2000.279.2.g437] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We examined the dynamic regulation of mucus gel thickness (MGT) in vivo in rat duodenum in response to luminal acid, cyclooxygenase (COX) inhibition, and exogenous PGE(2). An in vivo microscopic technique was used to measure MGT with fluorescent microspheres in urethan-anesthetized rats. Duodenal mucosa was topically superfused with pH 7.0 or pH 2.2 solutions with or without PGE(2) and indomethacin treatments. Glycoprotein concentration of duodenal loop perfusates was measured with periodic acid/Schiff (PAS) or Alcian blue (AB) staining. MGT and perfusate glycoprotein concentration were stable during a 35-min perfusion with pH 7.0 solution. Acid exposure increased MGT and PAS- and AB-positive perfusate glycoprotein concentrations. Indomethacin pretreatment increased both PAS- and AB-positive perfusate glycoprotein at baseline; subsequent acid superfusion decreased perfusate glycoproteins and gel thickness. PGE(2) (1 mg/kg iv) simultaneously increased MGT and PAS-positive perfusate glycoprotein concentrations followed by a transient increase in AB-positive glycoprotein concentration, suggesting contributions from goblet cells and Brunner's glands. Parallel changes in MGT and perfusate glycoprotein concentration in response to luminal acid and PGE(2) suggest that rapid MGT variations reflect alterations in the balance between mucus secretion and exudation, which in turn are regulated by a COX-related pathway. Luminal acid and PGE(2) augment mucus secretion from goblet cells and Brunner's glands.
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Affiliation(s)
- Y Akiba
- CURE: Digestive Diseases Research Center, University of California, Los Angeles 90073, USA
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Blasiak J, Trzeciak A, Malecka-Panas E, Drzewoski J, Wojewódzka M. In vitro genotoxicity of ethanol and acetaldehyde in human lymphocytes and the gastrointestinal tract mucosa cells. Toxicol In Vitro 2000; 14:287-95. [PMID: 10906435 DOI: 10.1016/s0887-2333(00)00022-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The influence of ethanol and acetaldehyde on DNA in human lymphocytes, gastric mucosa (GM) and colonic mucosa (CM) was investigated by using the comet assay. All kinds of cells were exposed to ethanol and acetaldehyde in two regimens: the cells were incubated with either chemical and analysed or they were exposed first to ethanol, washed and then exposed to acetaldehyde and analysed. Lymphocytes were exposed to ethanol at final concentrations of 30 mM and acetaldehyde at 3 mM. GM cells were incubated with ethanol at 1 M and acetaldehyde at 100 mM. CM cells were exposed to ethanol at 10 mM and acetaldehyde at 100 mM. In combined exposure, the cells were subsequently exposed to ethanol and acetaldehyde at all combination of the concentrations of the agents. Ethanol caused DNA strand breaks, which were repaired during 4 hr, except when this agent was applied in GM cells at a concentration of 1 M. A dose-dependent decrease in the tail moment of all types of acetaldehyde-treated cells was observed. Similar results were obtained when a recognized DNA crosslinking agent, formaldehyde, was used. These results suggest that acetaldehyde may form crosslinks with DNA. These crosslinks were poorly repaired. CM cells showed the highest sensitivity of all cell types to ethanol than lymphocytes and GM cells. There were no differences in the sensitivity to acetaldehyde of all the cell types. Our results clearly indicate that ethanol and acetaldehyde can contribute to cancers of the digestive tract.
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Affiliation(s)
- J Blasiak
- Department of Molecular Genetics, University of Lodz, 12/16, 90-237 Lodz, Banacha, Poland.
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33
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Affiliation(s)
- S E Harding
- NCMH Unit, University of Nottingham, School of Biological Sciences, Sutton Bonington, Leics., UK
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Abstract
This paper describes the purification of thioredoxin reductase (TR) and the characterization, purification, and cloning of thioredoxin (Trx) from Helicobacter pylori. Purification, amino acid sequence analysis, and molecular cloning of the gene encoding thioredoxin revealed that it is a 12-kDa protein which possesses the conserved redox active motif CGPC. The gene encoding Trx was amplified by polymerase chain reaction and inserted into a pET expression vector and used to transform Escherichia coli. Trx was overexpressed by induction with isopropyl-1-thio-beta-D-galactopyranoside as a decahistidine fusion protein and was recovered from the cytoplasm as a soluble and active protein. The redox activity of this protein was characterized using several mammalian proteins of different architecture but all containing disulfide bonds. H. pylori thioredoxin efficiently reduced insulin, human immunoglobulins (IgG/IgA/sIgA), and soluble mucin. Subcellular fractionation analysis of H. pylori revealed that thioredoxin was associated largely with the cytoplasm and inner membrane fractions of the cell in addition to being recovered in the phosphate-buffered saline-soluble fraction of freshly harvested cells. H. pylori TR was purified to homogeneity by chromatography on DEAE-52, Cibacron blue 3GA, and 2',5'-ADP-agarose. Gel filtration revealed that the native TR had a molecular mass of 70 kDa which represented a homodimer composed of two 35-kDa subunits, as determined by SDS-polyacrylamide gel electrophoresis. H. pylori TR (NADPH-dependent) efficiently catalyzed the reduction of 5,5'-dithiobis(nitrobenzoic acid) in the presence of either native or recombinant H. pylori Trx. H. pylori Trx behaved also as a stress response element as broth grown bacteria secreted Trx in response to chemical, biological, and environmental stresses. These observations suggest that Trx may conceivably assist H. pylori in the process of colonization by inducing focal disruption of the oligomeric structure of mucin while rendering host antibody inactive through catalytic reduction.
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Affiliation(s)
- H J Windle
- Department of Clinical Medicine, Trinity College Dublin, Trinity Centre for Health Sciences, St. James's Hospital, Dublin 8, Ireland.
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Gutiérrez-Cabano CA. Protection by intragastric polyethylene glycol 400 in rat stomach against ethanol damage involves alpha2-adrenoceptors. Dig Dis Sci 2000; 45:105-9. [PMID: 10695621 DOI: 10.1023/a:1005417612229] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
The aim of this study was to investigate the role of alpha2-adrenoceptors in the mechanism of intragastric polyethylene glycol 400 (PEG-400) protection against ethanol-induced gastric mucosal damage. In the injury study, 0.5 hr after subcutaneous control or yohimbine (5 mg/kg), a selective alpha2-adrenoceptor antagonist, rats were treated with intragastric vehicle or PEG-400 (5500 mg/kg). One hour later animals received 96% ethanol (gavage needle), 5 ml/kg, and the rats were killed after another hour. Total lengths of the gastric mucosal lesions were measured by an unbiased observer in a blinded fashion using a binocular magnifier having 5x magnification. In a separate set of experiments, 0.5 hr after subcutaneous control or yohimbine (5 mg/kg) rats received intragastric vehicle or PEG-400 (5500 mg/kg). One hour later gastric mucus volume, gastric juice volume, and gastric acid output in the gastric juice were measured. The protective effect offered by intragastric PEG-400 against ethanol-induced gastric mucosal damage was significantly diminished although not completely abolished by a selective alpha2-adrenoceptor antagonist (yohimbine). Yohimbine also significantly diminished both the basal and PEG-400-stimulated increase in gastric mucus volume. These findings suggest that the protective effect afforded by intragastric PEG-400 against ethanol-induced gastric mucosal damage is partially mediated by alpha2-adrenoceptors, and a mucus-dependent mechanism may be involved.
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Affiliation(s)
- C A Gutiérrez-Cabano
- Department of Surgical Pathology II, Faculty of Medical Sciences, National University of Rosario, Argentina
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Kodaira H, Ishihara K, Hotta K, Kagoshima M, Shimada H, Ishii K. Rat gastric mucous gel layer contains sialomucin not produced by the stomach. JAPANESE JOURNAL OF PHARMACOLOGY 1999; 81:86-93. [PMID: 10580375 DOI: 10.1254/jjp.81.86] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The sialylated mucus components of the normal gastric mucosa and mucous gel layer of rats were studied by using various histochemical staining methods including Maackia amurensis II (MAL-II) and Sambucus nigra (SNA) lectins, alcian blue (AB) pH 2.5 -- periodic acid Schiff (PAS) and high iron diamine (HID) -- AB pH 2.5. The acidic and neutral mucins characterized by the AB-PAS staining were abundantly present in the mucous gel layer as well as in the gastric mucosa. The sialomucin characterized by HID-AB was barely found in either the mucous gel layer or the mucosa. The sialomucin positive to MAL-II and SNA, which react with the N-acetyl neuraminic acid residue linked to galactose via an alpha-linkage, was moderately detected only in the mucous gel layer, but not in the entire mucosal layer. Furthermore, in animals given surgery to form an esophageal fistula through which saliva was excluded or in animals subjected to salivectomy, the mucous gel layer stained with MAL-II and SNA lectins was markedly decreased. These results indicate that a part of the sialomucin containing-mucous gel layer covering normal rat gastric mucosa originates from the saliva and that MAL-II and SNA lectins are useful for detecting this specific sialomucin.
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Affiliation(s)
- H Kodaira
- Department of Molecular Pharmacology, School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan
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37
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Imanishi H, Harihara Y, Bandai Y, Sanjo K, Makuuchi M. Reduced gastric surface mucus layer in experimental portal hypertension. J Gastroenterol 1997; 32:720-5. [PMID: 9430008 DOI: 10.1007/bf02936946] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The pathogenesis of portal hypertensive gastropathy has not yet been thoroughly elucidated. Changes in the gastric surface mucus layer in prehepatic portal hypertensive and cirrhotic rat models were studied by observing frozen sections fixed with formaldehyde vapor and stained with hematoxylin and eosin. We produced prehepatic portal hypertensive rats by partial ligation of the portal vein, and cirrhotic rats by prolonged administration of carbon tetrachloride (CCl4) and phenobarbital sodium. The thickness of the corporal and antral gastric surface mucus was significantly reduced in prehepatic portal hypertensive and cirrhotic rats compared with the values obtained in control rats for portal hypertension (subjected to sham operation) and control rats for cirrhosis (treated with phenobarbital but not CCl4). These results indicate that the hemodynamic changes associated with portal hypertension reduce the thickness of the gastric surface mucus layer and may be one of the causes of the gastropathy associated with portal hypertension.
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Affiliation(s)
- H Imanishi
- Second Department of Surgery, Faculty of Medicine, University of Tokyo, Japan
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Keogh JP, Allen A, Garner A. Relationship between gastric mucus synthesis, secretion and surface gel erosion measured in amphibian stomach in vitro. Clin Exp Pharmacol Physiol 1997; 24:844-9. [PMID: 9363367 DOI: 10.1111/j.1440-1681.1997.tb02701.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
1. The layer of adherent mucus that protects the surface of the stomach reflects a dynamic balance between biosynthesis of glycoprotein, secretion of preformed mucus and erosion of the adherent gel layer. The present study is the first in which all these processes have been measured concomitantly and was undertaken to define interrelationships between the three parameters. 2. A chambered sac preparation of amphibian gastric mucosa is described. Biosynthesis was determined by specific incorporation of radiolabelled sugars into purified glycoprotein. Mucus secretion was determined by measuring the thickness of the adherent gel and erosion of the surface layer was assessed from the appearance of soluble mucin in the luminal solution. 3. 16,16-Dimethyl-prostaglandin (PG) E2 stimulated glucosamine incorporation by 10-fold, but did not alter the rate of incorporation of galactose. There was a rapid two-fold increase in the thickness of the adherent mucus layer but no change in the rate of erosion. Dibutyryl-cAMP also stimulated mucus release but, unlike PG, increased glycoprotein labelling by galactose. 4. Both distention or the application of a cholinergic agonist increased adherent mucus thickness. Stimulation of mucus release in response to carbachol was accompanied by a decrease in glycoprotein labelling by galactose. In contrast, the adrenergic agent noradrenaline decreased secretion but did not influence labelling. 5. These results indicate that biosynthesis and secretion of gastric mucus are subject to differential regulation. Moreover, the profile of incorporation of sugars in response to secretagogues also differs, indicating the need for caution when interpreting effects on glycoprotein biosynthesis.
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Affiliation(s)
- J P Keogh
- Department of Physiological Sciences, Medical School, University of Newcastle upon Tyne, United Kingdom
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Lin SY, Wu CW, Li MJ, Liang RC. Infra-red (ATR/FT) spectroscopic study on the conformational structure of the isolated human gastric mucus pretreated with ethanol. J Gastroenterol Hepatol 1997; 12:707-12. [PMID: 9430034 DOI: 10.1111/j.1440-1746.1997.tb00357.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In order to investigate the conformational structure of isolated human gastric mucus gel pretreated with or without ethanol, gel samples were determined by attenuated total reflection/Fourier transform-infra-red (ATR/FT-IR) microspectroscopy. The result indicates that the secondary structure-dependent amide I band and the glycoprotein region were significantly different in the gastric mucus gels pretreated with and without 40% ethanol. The structural composition of beta-sheet structure (1640-1600 cm-1) increased from 38.48 to 55.08% (+16.6%) after 6-hour pretreatment with 40% ethanol, but the beta-turn structure, (1660-1700 cm-1) decreased from 41.38 to 24.29% (-17.05%). The peak area ranging from 1180 to 1000 cm-1, assigned to the glycoprotein region, was also different after pretreatment with ethanol for 6 h. The higher peak area of the carbohydrate band was obtained in the frequency region between 1000 and 1040 cm-1 and 1100 and 1180 cm-1 for mucus gel pretreated with 40% ethanol. However, the peak area ranging from 1100 to 1040 cm-1 mainly due to the symmetric phosphate stretching mode of proteins was somewhat lower for the ethanol-pretreated mucus gel than the native mucus gel. This result strongly reveals that ethanol significantly modified the conformational structure of proteins and carbohydrates of gastric mucus gel. We propose that the dehydration and interference of hydrophobic interactions in the isolated mucus gel after pretreatment with ethanol might be responsible for this conformational change.
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Affiliation(s)
- S Y Lin
- Department of Medical Research and Education, Veterans General Hospital-Taipei, Taiwan, ROC
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40
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Iiboshi Y, Nezu R, Khan J, Chen K, Cui L, Yoshida H, Wasa M, Fukuzawa M, Kamata S, Takagi Y, Okada A. Developmental changes in distribution of the mucous gel layer and intestinal permeability in rat small intestine. JPEN J Parenter Enteral Nutr 1996; 20:406-11. [PMID: 8950741 DOI: 10.1177/014860719602000606] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND From the developmental aspects, the distribution of fluorescein isothiocyanate dextran 70,000 (FTTC-dextran) and mucous gel across the lumen of small intestine was observed as an investigation into the role of mucous gel on intestinal permeability. Furthermore, the effect of N-acetyl cysteine (NAC), a mucolytic agent, on intestinal permeability was examined. METHODS In suckling and weaned rats, FTTC-dextran (750 mg/kg body wt) was gavage-fed. After 3 hours, blood samples were taken by cardiac puncture to analyze plasma FTTC-dextran by fluorescence spectrometry. Samples of small intestine with luminal contents were frozen and sectioned in a cryostat for fluorescence microscopy; the same sections were placed in a 0.2% celloidin solution to preserve mucous gel and were stained by periodic acid-Schiff reaction for light microscopy. In weaned rats, intestinal permeability was examined with different concentrations of intraluminally instilled NAC. RESULTS The plasma level of FTTC-dextran showed a significant increase (p < .01) in suckling rats compared with the weaned rats. Morphologic findings were similar in both the jejunum and ileum: The spaces between villi were not entirely filled with mucus but filled with FTTC-dextran in suckling rats, whereas the spaces were filled with mucus and not filled with FTTC-dextran in weaned rats. Intestinal permeability in groups with NAC were significantly higher (p < .01) than that in group without NAC. CONCLUSIONS These results suggest that an increase in the mucous gel layer that coats the epithelial lining according to the maturation of the gastrointestinal tract is one of the most important factors for a restriction in intestinal permeability.
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Affiliation(s)
- Y Iiboshi
- Department of Pediatric Surgery, Osaka University Medical School, Japan
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Enss ML, Müller H, Schmidt-Wittig U, Kownatzki R, Coenen M, Hedrich HJ. Effects of perorally applied endotoxin on colonic mucins of germfree rats. Scand J Gastroenterol 1996; 31:868-74. [PMID: 8888433 DOI: 10.3109/00365529609051994] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND The intestinal epithelium, with the potential to restrict luminal noxae from the host, secretes a mucous layer with various protective functions. Microbial colonization of germfree (GF) rats stimulates this mucin-secreting tissue. The present study determined the effect of bacterial lipopolysaccharides (LPS) on this process. METHODS One, 3, and 5 days after peroral application of 35 micrograms LPS/100 g body weight (from Escherichia coli O55:B5), LPS concentrations were monitored in ingesta, intestinal tissue, and liver. Mucin high molecular weight glycoproteins (HMG), released in response to LPS, were isolated and separated into mucins, i) attached to the colonic epithelium (EM) and ii) mixed to the luminal content (LM), respectively. Subsequently, the binding capacity of both mucin fractions for various lectins and for type-1 pili expressing E. coli was determined. RESULTS Ingesta and tissue had maximal LPS concentrations on days 3 (jejunum) and 5 (colon). Maximal EM secretion was found on day 3, release of LM further increased to day 5. Both mucin fractions had altered glycosylation patterns: augmentation of beta-galactose, alpha-N-acetyl galactosamine, and mannose coincided with a decrease in alpha-fucose. Compared with the controls, attachment of E. coli to EM increased slightly on day 1 only; the binding capacity of LM increased continuously up to day 5. CONCLUSION Results suggest that mucins, released in response to LPS, in addition to the epithelial protection, support the gut microbial clearance system.
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Affiliation(s)
- M L Enss
- Dept. for Laboratory Animal Science and Animal Facility, Medical School Hanover, Germany
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Parkkila S, Parkkila AK. Carbonic anhydrase in the alimentary tract. Roles of the different isozymes and salivary factors in the maintenance of optimal conditions in the gastrointestinal canal. Scand J Gastroenterol 1996; 31:305-17. [PMID: 8726296 DOI: 10.3109/00365529609006403] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- S Parkkila
- Laboratory of Oulu University Hospital, Finland
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43
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Iiboshi Y, Nezu R, Cui L, Chen K, Khan J, Yoshida H, Sando K, Kamata S, Takagi Y, Okada A. Adhesive mucous gel layer and mucus release as intestinal barrier in rats. JPEN J Parenter Enteral Nutr 1996; 20:98-104. [PMID: 8676540 DOI: 10.1177/014860719602000298] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Although it has been reported that total parenteral nutrition induces an increased intestinal permeability and a decreased mucous gel layer covering the intestinal epithelium, the role of mucous gel on intestinal permeability has not been well understood. We examined the in vivo effects of N-acetyl cysteine (NAC) as mucolytic agent and colchicine as suppressant of the mucus production on the intestinal transmission of fluorescein isothiocyanate dextran 70,000 (FITC-dextran). METHODS Rats were divided into four groups. In each group, FITC-dextran (750 mg/kg) with or without NAC (3000 mg/kg) was injected into the small intestinal lumen 3 hours after intraperitoneal injection of saline or colchicine (Col, 10 mg/kg). Thirty minutes after injection of FITC-dextran, blood samples were taken from portal vein to analyze plasma fluorescein concentration by fluorescence spectrometry. Samples of small intestine were sectioned in a cryostat for fluorescence microscopy, and the identical sections were stained by periodic acid-Schiff reaction. RESULTS Plasma FITC-dextran level in NAC group was higher than that in control group (p < .01), that in Col + NAC group was higher than that in Col group (p < .01) and that in Col + NAC group was higher than that in NAC group (p < .05). The spaces between villi were filled with mucous gel in the control and Col groups, whereas those were not entirely filled with mucous gel in NAC and Col + NAC groups. FITC-dextran and mucous gel showed complementary distribution in all rats. The villous interstitial edema was recognized in NAC group and the villi were disrupted in Col + NAC group. CONCLUSIONS These results suggest that intestinal permeability is possibly affected not only by the mucous gel covering the intestinal epithelium but also by mucus release from goblet cells of the small intestine.
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Affiliation(s)
- Y Iiboshi
- Department of Pediatric Surgery, Osaka University Medical School, Japan
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Abstract
BACKGROUND In vitro studies have shown that pH is an important determinant of mucus structure and function, but the relationship in vivo is unclear. Omeprazole increases intragastric pH and also allows bacterial overgrowth. In this study we have assessed the effect of omeprazole on gastric juice viscosity and examined the influence of pH and bacterial overgrowth on the resulting change. METHODS Gastric juice specific viscosity, pH and total bacterial counts were measured in nine healthy male volunteers before and after omeprazole 20 mg twice daily for 1 week. The effect of incubation at pH 2 and 7 was also determined. Viscosity changes were compared with changes in pH and bacterial counts. RESULTS Mean viscosity fell (P < 0.05) following treatment, though there was a wide range in viscosity both before and after treatment. The decrease was reproduced by incubation of pre-treatment juice at pH 7 but not pH 2. The fall in viscosity was correlated (P < 0.05) with change pH. CONCLUSION Omeprazole decreases gastric juice, and hence gastric mucus, viscosity by increasing intragastric pH. This could be important if it allows improved penetration of antimicrobials to Helicobacter pylori within the mucus layer.
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Affiliation(s)
- A F Goddard
- Division of Gastroenterology, University Hospital, Nottingham, UK
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45
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Lin SY, Wu CW, Liang RC. Effect of ethanol on the protein secondary structure of the human gastric mucosa, in vitro. EUROPEAN JOURNAL OF CLINICAL CHEMISTRY AND CLINICAL BIOCHEMISTRY : JOURNAL OF THE FORUM OF EUROPEAN CLINICAL CHEMISTRY SOCIETIES 1995; 33:255-61. [PMID: 7578601 DOI: 10.1515/cclm.1995.33.5.255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effect of ethanol on the secondary conformational structure of proteins of the human gastric mucosa was investigated by attenuated total reflection/Fourier transform infrared (ATR/FT-IR) spectroscopy. The IR peak intensity and position of each structural component of gastric mucosa was found to change significantly with the ethanol concentration and length of exposure. The peak intensity due to the beta-sheet and/or beta-turn conformational structure in amide I and II bands of gastric mucosa clearly increased after treatment with ethanol. Moreover, the peak at 1635 cm-1 shifted to 1630 cm-1 after treatment with 40% ethanol for 3 h, or 80% ethanol for 1 h, and a distinct shoulder also appeared at 1643 cm-1. This shift occurred more rapidly and was more pronounced after exposure of mucosa to 80% ethanol, compared with the effect of 40% ethanol, but the alpha-helical structure at the amide I and II bands was not influenced by either concentration of ethanol. Ethanol treatment might also transform the secondary structure of amide III in gastric mucosa from an alpha-helix to a mainly random coil with extensive unfolding. The absorption between 1180 and 980 cm-1, which is assigned to glycoprotein structure, was also reduced after treatment with ethanol. This strongly indicates that ethanol influences the conformation of the lipids and proteins of human gastric mucosa, leading to their deformation.
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Affiliation(s)
- S Y Lin
- Department of Medical Research and Education, Veterans General Hospital-Taipei, Republic of China
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Endoh K, Leung FW. Effects of smoking and nicotine on the gastric mucosa: a review of clinical and experimental evidence. Gastroenterology 1994; 107:864-78. [PMID: 7915701 DOI: 10.1016/0016-5085(94)90138-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Epidemiological and experimental evidence have shown that nicotine has harmful effects on the gastric mucosa. The mechanisms by which cigarette smoking or nicotine adversely affect the gastric mucosa have not been fully elucidated. In this report, clinical and experimental data are reviewed. The effects of nicotine from smoking on gastric aggressive or defensive factors are discussed. Nicotine potentiates gastric aggressive factors and attenuates defensive factors; it also increases acid and pepsin secretions, gastric motility, duodenogastric reflux of bile salts, the risk of Helicobacter pylori infection, levels of free radicals, and platelet-activating factor, endothelin generation, and vasopressin secretion. Additionally, nicotine impairs the therapeutic effect of H2-receptor antagonists and decreases prostaglandin synthesis, gastric mucosal blood flow, mucus secretion, and epidermal growth factor secretion. Although many of the studies provide conflicting results, the bulk of the evidence supports the hypothesis that nicotine is harmful to the gastric mucosa.
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Affiliation(s)
- K Endoh
- First Department of Internal Medicine, Nagoya City University Medical School, Japan
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Iiboshi Y, Nezu R, Kennedy M, Fujii M, Wasa M, Fukuzawa M, Kamata S, Takagi Y, Okada A. Total parenteral nutrition decreases luminal mucous gel and increases permeability of small intestine. JPEN J Parenter Enteral Nutr 1994; 18:346-50. [PMID: 7523742 DOI: 10.1177/014860719401800412] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The distribution of fluorescein isothiocyanate dextran 70,000 (FITC-dextran) and mucous gel across the lumen of small intestine was observed as an investigation into the role of mucous gel on permeability in total parenteral nutrition (TPN). Thirty-two rats were randomly divided into two groups fed with either TPN or oral rat food. On day 4 or 7, FITC-dextran (750 mg/kg body weight) was given through the gastroduodenal tube. After 1 hour, blood samples were taken by aortic puncture to analyze plasma FITC-dextran by fluorescence spectrometry. Samples of small intestine with luminal contents were frozen and sectioned in a cryostat for fluorescence microscopy; the same sections were placed in a 0.2% celloidin solution for 3 minutes to preserve mucous gel and stained by periodic acid-Schiff reaction for light microscopy. The plasma level of FITC-dextran after 1 hour of this marker injection showed a significant increase (p < .01) in the TPN group compared with the rat food group on days 4 and 7. Morphologic findings on days 4 and 7 were similar in both the jejunum and ileum: The mucous gel filled the spaces between villi and FITC-dextran centered in the lumen in the rat food group, whereas the mucous gel decreased and FITC-dextran filled the spaces between villi in the TPN group. FITC-dextran and mucous gel showed complementary distributions in both groups. These data suggest that TPN decreases luminal mucous gel and increases permeability of small intestine in rats.
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Affiliation(s)
- Y Iiboshi
- Department of Pediatric Surgery, Osaka University Medical School, Japan
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Endoh K, Kao J, Baker M, Leung FW. Involvement of alpha 2-adrenoceptors in mechanism of intragastric nicotine protection against ethanol injury in rat stomach. Dig Dis Sci 1993; 38:713-21. [PMID: 8096456 DOI: 10.1007/bf01316805] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
To elucidate the role of alpha- and beta-adrenoceptors in the mechanism of intragastric nicotine protection against ethanol-induced gastric mucosal injury, the following studies were performed. At 0.5-hr prior to the injury study, rats were pretreated with: subcutaneous control, prazosin (0.5 mg/kg) or yohimbine (5 mg/kg) to block alpha 1- or alpha 2-adrenoceptors; or intraperitoneal control, metoprolol (2 mg/kg) or butoxamine (4 mg/kg) to block beta 1- or beta 2-adrenoceptors, respectively. At 1-hr intervals, rats received intragastric vehicle or nicotine (4 mg/kg) and 40% ethanol (10 ml/kg). Total lengths of the linear gastric corpus mucosal lesions were measured by an unbiased observer using a caliper. In a separate study, 0.5-hr after subcutaneous control or yohimbine (5 mg/kg), rats were treated with intragastric vehicle or nicotine (4 mg/kg). One hour later, gastric mucus volume, gastric juice volume and pH, and titratable acid in the gastric juice were measured. In the rat stomach, the intragastric nicotine protection against 40% ethanol-induced mucosal injury was not blocked by selective alpha 1-(prazosin), beta 1-(metoprolol), or beta 2-(butoxamine) adrenoceptor antagonists. The protection was significantly reduced although not completely abolished by selective alpha 2-(yohimbine) adrenoceptor antagonist. Yohimbine also significantly reduced basal and nicotine-stimulated increase in gastric mucus volume. These data suggest that alpha 2-adrenoceptors are involved in the protective effect of intragastric nicotine against 40% ethanol-induced gastric mucosal injury possibly by a mucus-dependent mechanism.
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Affiliation(s)
- K Endoh
- Research Service, Sepulveda Veterans Administration Medical Center, California 91343
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49
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Endoh K, Kao J, Baker M, Leung FW. Intragastric nicotine protection against 40% ethanol injury in rat stomach. Role of ganglionic stimulation or blockade. Dig Dis Sci 1992; 37:1840-6. [PMID: 1361905 DOI: 10.1007/bf01308077] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
Intragastric nicotine (4 mg/kg) protects against 40% ethanol-induced gastric mucosal injury and raises mean blood pressure. We postulated that this protective effect was mediated by the ganglionic stimulatory property of nicotine and therefore could be abolished by ganglionic blockers. Rats were pretreated with intraperitoneal hexamethonium (10 mg/kg) or mecamylamine (2 mg/kg) to block peripheral or central autonomic ganglia, respectively. Intragastric vehicle or nicotine (4 mg/kg) was then administered. The total lengths of the linear gastric corpus mucosal lesions induced by intragastric 40% ethanol were measured by an unbiased observer using a caliper. The results showed that both intraperitoneal hexamethonium and mecamylamine pretreatments protected against 40% ethanol-induced gastric mucosal injury. Neither modified the protective effect of intragastric nicotine. The protective effect of hexamethonium and mecamylamine was associated with a significant increase in the volume of gastric mucus and gastric juice. The increase in the volume of gastric content (mucus and juice) was partially responsible for the protective effect of these ganglionic blockers. In a separate experiment, intraperitoneal nicotine (4 mg/kg) also protected against 40% ethanol-induced gastric mucosal injury and raised mean blood pressure. These data indicate that the protection against 40% ethanol-induced gastric mucosal injury is not unique to intragastric nicotine. Such protection can be induced by ganglionic blocking doses of hexamethonium and mecamylamine, or a ganglionic stimulatory dose of intraperitoneally administered nicotine. Whether ganglionic stimulation or blockade plays a role in the mechanism of intragastric nicotine protection, however, remains to be determined.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- K Endoh
- Research Service, Sepulveda Veterans Administration Medical Center 91343
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50
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Affiliation(s)
- J T Lamont
- Section of Gastroenterology/Hepatology, University Hospital, Boston, Massachusetts
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