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PubMed Central (PMC3 - NLM DTD) (2,682,993 recursos)
Archive of life sciences journal literature at the U.S. National Institutes of Health (NIH), developed and managed by NIH's National Center for Biotechnology Information (NCBI) in the National Library of Medicine (NLM).

American Journal of Physiology - Gastrointestinal and Liver Physiology

Mostrando recursos 121 - 140 de 774

121. Dipeptidyl peptidase IV inhibition potentiates amino acid- and bile acid-induced bicarbonate secretion in rat duodenum - Inoue, Takuya; Wang, Joon-Ho; Higashiyama, Masaaki; Rudenkyy, Sergiy; Higuchi, Kazuhide; Guth, Paul H.; Engel, Eli; Kaunitz, Jonathan D.; Akiba, Yasutada
Intestinal endocrine cells release gut hormones, including glucagon-like peptides (GLPs), in response to luminal nutrients. Luminal l-glutamate (l-Glu) and 5′-inosine monophosphate (IMP) synergistically increases duodenal HCO3− secretion via GLP-2 release. Since L cells express the bile acid receptor TGR5 and dipeptidyl peptidase (DPP) IV rapidly degrades GLPs, we hypothesized that luminal amino acids or bile acids stimulate duodenal HCO3− secretion via GLP-2 release, which is enhanced by DPPIV inhibition. We measured HCO3− secretion with pH and CO2 electrodes using a perfused rat duodenal loop under isoflurane anesthesia. l-Glu (10 mM) and IMP (0.1 mM) were luminally coperfused with or without...

122. Altered colorectal afferent function associated with TNBS-induced visceral hypersensitivity in mice - Feng, Bin; La, Jun-Ho; Tanaka, Takahiro; Schwartz, Erica S.; McMurray, Timothy P.; Gebhart, G. F.
Inflammation of the distal bowel is often associated with abdominal pain and hypersensitivity, but whether and which colorectal afferents contribute to the hypersensitivity is unknown. Using a mouse model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis, we investigated colorectal hypersensitivity following intracolonic TNBS and associated changes in colorectum and afferent functions. C57BL/6 mice were treated intracolonically with TNBS or saline. Visceromotor responses to colorectal distension (15–60 mmHg) were recorded over 8 wk in TNBS- and saline-treated (control) mice. In other mice treated with TNBS or saline, colorectal inflammation was assessed by myeloperoxidase assay and immunohistological staining. In vitro single-fiber recordings were...

123. CD18 is required for optimal lymphopenia-induced proliferation of mouse T cells - Sarin, Ritu; Abraham, Clara
Lymphocyte numbers are tightly regulated; with acute lymphopenia, T cell numbers are reestablished through lymphopenia-induced proliferation. In contrast to the costimulation requirements of antigen-driven proliferation, a number of costimulatory molecules are not required for lymphopenia-induced proliferation. However, the requirement for major histocompatibility complex (MHC)-T cell receptor (TCR) interactions and the enhanced lymphopenia-induced proliferation in T cells with higher TCR affinity argue for a role for surface molecules that contribute to efficient MHC-TCR interactions, in particular adhesion molecules. CD18 is an integrin that contributes to the activation of peripheral and intestinal T cells through adhesive and costimulatory mechanisms. We found that...

124. Luminal hypertonicity and acidity modulate colorectal afferents and induce persistent visceral hypersensitivity - La, Jun-Ho; Feng, Bin; Schwartz, Erica S.; Brumovsky, Pablo R.; Gebhart, G. F.
Carbohydrate malabsorption such as in lactose intolerance or enteric infection causes symptoms that include abdominal pain. Because this digestive disorder increases intracolonic osmolarity and acidity by accumulation of undigested carbohydrates and fermented products, we tested whether these two factors (hypertonicity and acidity) would modulate colorectal afferents in association with colorectal nociception and hypersensitivity. In mouse colorectum-pelvic nerve preparations in vitro, afferent activities were monitored after application of acidic hypertonic saline (AHS; pH 6.0, 800 mosM). In other experiments, AHS was instilled intracolonically to mice and behavioral responses to colorectal distension (CRD) measured. Application of AHS in vitro excited 80% of...

125. Chronic ethanol feeding enhances miR-21 induction during liver regeneration while inhibiting proliferation in rats - Dippold, Rachael P.; Vadigepalli, Rajanikanth; Gonye, Gregory E.; Hoek, Jan B.
Liver regeneration is an important repair response to liver injury. Chronic ethanol consumption inhibits and delays liver regeneration in experimental animals. We studied the effects of chronic ethanol treatment on messenger RNA (mRNA) and microRNA (miRNA) expression profiles during the first 24 h after two-thirds partial hepatectomy (PHx) and found an increase in hepatic miR-21 expression in both ethanol-fed and pair-fed control rats after PHx. We demonstrate that the increase of miR-21 expression during liver regeneration is more robust in ethanol-fed rats. Peak miR-21 expression occurs at 24 h after PHx in both ethanol-fed and control rats, corresponding to the...

126. Colonic mucosal microbiome differs from stool microbiome in cirrhosis and hepatic encephalopathy and is linked to cognition and inflammation - Bajaj, Jasmohan S.; Hylemon, Phillip B.; Ridlon, Jason M.; Heuman, Douglas M.; Daita, Kalyani; White, Melanie B.; Monteith, Pamela; Noble, Nicole A.; Sikaroodi, Masoumeh; Gillevet, Patrick M.
Although hepatic encephalopathy (HE) is linked to the gut microbiota, stool microbiome analysis has not found differences between HE and no-HE patients. This study aimed to compare sigmoid mucosal microbiome of cirrhotic patients to controls, between HE vs. no-HE patients, and to study their linkage with cognition and inflammation. Sixty cirrhotic patients (36 HE and 24 no-HE) underwent cognitive testing, stool collection, cytokine (Th1, Th2, Th17, and innate immunity), and endotoxin analysis. Thirty-six patients (19 HE and 17 no-HE) and 17 age-matched controls underwent sigmoid biopsies. Multitag pyrosequencing (including autochthonous genera, i.e., Blautia, Roseburia, Fecalibacterium, Dorea) was performed on stool...

127. Pomegranate seed oil reduces intestinal damage in a rat model of necrotizing enterocolitis - Coursodon-Boyiddle, Christine F.; Snarrenberg, Chelsea L.; Adkins-Rieck, Camille K.; Bassaganya-Riera, Josep; Hontecillas, Raquel; Lawrence, Peter; Brenna, J. Thomas; Jouni, Zeina E.; Dvorak, Bohuslav
Pomegranate seed oil (PSO), which is the major source of conjugated linolenic acids such as punicic acid (PuA), exhibits strong anti-inflammatory properties. Necrotizing enterocolitis (NEC) is a devastating disease associated with severe and excessive intestinal inflammation. The aim of this study was to evaluate the effects of orally administered PSO on the development of NEC, intestinal epithelial proliferation, and cytokine regulation in a rat model of NEC. Premature rats were divided into three groups: dam fed (DF), formula-fed rats (FF), or rats fed with formula supplemented with 1.5% of PSO (FF + PSO). All groups were exposed to asphyxia/cold stress...

128. Conditional deletion of menin results in antral G cell hyperplasia and hypergastrinemia - Veniaminova, Natalia A.; Hayes, Michael M.; Varney, Jessica M.; Merchant, Juanita L.
Antral gastrin is the hormone known to stimulate acid secretion and proliferation of the gastric corpus epithelium. Patients with mutations in the multiple endocrine neoplasia type 1 (MEN1) locus, which encodes the protein menin, develop pituitary hyperplasia, insulinomas, and gastrinomas in the duodenum. We previously hypothesized that loss of menin leads to derepression of the gastrin gene and hypergastrinemia. Indeed, we show that menin represses JunD induction of gastrin in vitro. Therefore, we examined whether conditional deletion of Men1 (Villin-Cre and Lgr5-EGFP-IRES-CreERT2), with subsequent loss of menin from the gastrointestinal epithelium, increases gastrin expression. We found that epithelium-specific deletion of...

129. Cerulein hyperstimulation decreases AMP-activated protein kinase levels at the site of maximal zymogen activation - Shugrue, Christine A.; Alexandre, Martine; de Villalvilla, Alexander Diaz; Kolodecik, Thomas R.; Young, Lawrence H.; Gorelick, Fred S.; Thrower, Edwin C.
The premature activation of digestive enzyme zymogens in the pancreatic acinar cell is an important initiating event in acute pancreatitis. We have previously demonstrated that vacuolar ATPase (vATPase) activity is required for zymogen activation. Adenosine monophosphate-activated protein kinase (AMPK) regulates vATPase function in kidney and epididymal clear cells. To determine whether AMPK could affect pancreatitis responses, its effects were first examined in a cellular model of pancreatitis, cerulein-hyperstimulated (100 nM) pancreatic acini. This treatment caused a prominent increase in trypsin and chymotrypsin activities. Pretreatment with AICAR or metformin (AMPK activators) or compound C (an AMPK inhibitor) reduced or increased cerulein-induced...

130. Bioengineered human IAS reconstructs with functional and molecular properties similar to intact IAS - Singh, Jagmohan; Rattan, Satish
Because of its critical importance in rectoanal incontinence, we determined the feasibility to reconstruct internal anal sphincter (IAS) from human IAS smooth muscle cells (SMCs) with functional and molecular attributes similar to the intact sphincter. The reconstructs were developed using SMCs from the circular smooth muscle layer of the human IAS, grown in smooth muscle differentiation media under sterile conditions in Sylgard-coated tissue culture plates with central Sylgard posts. The basal tone in the reconstructs and its changes were recorded following 0 Ca2+, KCl, bethanechol, isoproterenol, protein kinase C (PKC) activator phorbol 12,13-dibutyrate, and Rho kinase (ROCK) and PKC inhibitors...

131. Inhibition of long myosin light-chain kinase activation alleviates intestinal damage after binge ethanol exposure and burn injury - Zahs, Anita; Bird, Melanie D.; Ramirez, Luis; Turner, Jerrold R.; Choudhry, Mashkoor A.; Kovacs, Elizabeth J.
Laboratory evidence suggests that intestinal permeability is elevated following either binge ethanol exposure or burn injury alone, and this barrier dysfunction is further perturbed when these insults are combined. We and others have previously reported a rise in both systemic and local proinflammatory cytokine production in mice after the combined insult. Knowing that long myosin light-chain kinase (MLCK) is important for epithelial barrier maintenance and can be activated by proinflammatory cytokines, we examined whether inhibition of MLCK alleviated detrimental intestinal responses seen after ethanol exposure and burn injury. To accomplish this, mice were given vehicle or a single binge ethanol...

132. Tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone initiates and enhances pancreatitis responses - Alexandre, M.; Uduman, A. K.; Minervini, S.; Raoof, A.; Shugrue, C. A.; Akinbiyi, E. O.; Patel, V.; Shitia, M.; Kolodecik, T. R.; Patton, R.; Gorelick, F. S.; Thrower, E. C.
Clinical studies indicate that cigarette smoking increases the risk for developing acute pancreatitis. The nicotine metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a major cigarette smoke toxin. We hypothesized that NNK could sensitize to pancreatitis and examined its effects in isolated rat pancreatic acini and in vivo. In acini, 100 nM NNK caused three- and fivefold activation of trypsinogen and chymotrypsinogen, respectively, above control. Furthermore, NNK pretreatment in acini enhanced zymogen activation in a cerulein pancreatitis model. The long-term effects of NNK were examined in vivo after intraperitoneal injection of NNK (100 mg/kg body wt) three times weekly for 2 wk. NNK alone...

133. Suppression of IL-8 production in gastric epithelial cells by MUC1 mucin and peroxisome proliferator-associated receptor-γ - Park, Yong Sung; Guang, Wei; Blanchard, Thomas G.; Chul Kim, K.; Lillehoj, Erik P.
MUC1 is a membrane-tethered mucin expressed on the apical surface of epithelial cells. Our previous report (Guang W, Ding H, Czinn SJ, Kim KC, Blanchard TG, Lillehoj EP. J Biol Chem 285: 20547–20557, 2010) demonstrated that expression of MUC1 in AGS gastric epithelial cells limits Helicobacter pylori infection and reduces bacterial-driven IL-8 production. In this study, we identified the peroxisome proliferator-associated receptor-γ (PPARγ) upstream of MUC1 in the anti-inflammatory pathway suppressing H. pylori- and phorbol 12-myristate 13-acetate (PMA)-stimulated IL-8 production. Treatment of AGS cells with H. pylori or PMA increased IL-8 levels in cell culture supernatants compared with cells treated...

134. Esophageal wall blood perfusion during contraction and transient lower esophageal sphincter relaxation in humans - Jiang, Yanfen; Bhargava, Valmik; Kim, Young Sun; Mittal, Ravinder K.
We recently reported that esophageal contraction reduces esophageal wall perfusion in an animal study. Our aim was to determine esophageal wall blood perfusion (EWBP) during esophageal contraction and transient lower esophageal sphincter relaxations (TLESRs) in humans. We studied 12 healthy volunteers. A custom-designed laser Doppler probe was anchored to the esophageal wall, 4–6 cm above the LES, by use of the Bravo pH system so that the laser light beam stay directed toward the esophageal mucosa. A high-resolution manometry equipped with impedance electrodes recorded esophageal pressures and reflux events. Synchronized pressure, impedance, pH, and EWBP recordings were obtained during dry...

135. HCl-induced and ATP-dependent upregulation of TRPV1 receptor expression and cytokine production by human esophageal epithelial cells - Ma, Jie; Altomare, Annamaria; Guarino, Michele; Cicala, Michele; Rieder, Florian; Fiocchi, Claudio; Li, Dan; Cao, Weibiao; Behar, Jose; Biancani, Piero; Harnett, Karen M.
The pathogenesis of gastroesophageal reflux disease (GERD) remains elusive, but recent evidence suggests that early secretion of inflammatory cytokines and chemokines by the mucosa leads to influx of immune cells followed by tissue damage. We previously showed that exposure of esophageal mucosa to HCl causes ATP release, resulting in activation of acetyl-CoA:1-O-alkyl-sn-glycero-3-phosphocholine acetyltransferase (lyso-PAF AT), the enzyme responsible for the production of platelet-activating factor (PAF). In addition, HCl causes release of IL-8 from the esophageal mucosa. We demonstrate that esophageal epithelial cells secrete proinflammatory mediators in response to HCl and that this response is mediated by ATP. Monolayers of the...

136. Indomethacin-induced translocation of bacteria across enteric epithelia is reactive oxygen species-dependent and reduced by vitamin C - Schoultz, Ida; McKay, Catherine M.; Graepel, Rabea; Phan, Van C.; Wang, Arthur; Söderholm, Johan; McKay, Derek M.
The enteric epithelium must absorb nutrients and water and act as a barrier to the entry of luminal material into the body; this barrier function is a key component of innate immunity. Nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy occurs via inhibition of prostaglandin synthesis and perturbed epithelial mitochondrial activity. Here, the direct effect of NSAIDs [indomethacin, piroxicam (cyclooxygenase 1 and 2 inhibitors), and SC-560 (a cyclooxygenase 1 inhibitor)] on the barrier function of human T84 epithelial cell line monolayers was assessed by transepithelial electrical resistance (TER) and internalization and translocation of a commensal Escherichia coli. Exposure to E. coli in the...

137. Enteral nutrients potentiate glucagon-like peptide-2 action and reduce dependence on parenteral nutrition in a rat model of human intestinal failure - Brinkman, Adam S.; Murali, Sangita G.; Hitt, Stacy; Solverson, Patrick M.; Holst, Jens J.; Ney, Denise M.
Glucagon-like peptide-2 (GLP-2) is a nutrient-dependent, proglucagon-derived gut hormone that shows promise for the treatment of short bowel syndrome (SBS). Our objective was to investigate how combination GLP-2 + enteral nutrients (EN) affects intestinal adaption in a rat model that mimics severe human SBS and requires parenteral nutrition (PN). Male Sprague-Dawley rats were assigned to one of five groups and maintained with PN for 18 days: total parenteral nutrition (TPN) alone, TPN + GLP-2 (100 μg·kg−1·day−1), PN + EN + GLP-2(7 days), PN + EN + GLP-2(18 days), and a nonsurgical oral reference group. Animals underwent massive distal bowel resection...

138. Reproducibility of swallow-induced cortical BOLD positive and negative fMRI activity - Babaei, Arash; Ward, B. Douglas; Ahmad, Shahryar; Patel, Anna; Nencka, Andrew; Li, Shi-Jiang; Hyde, James; Shaker, Reza
Functional MRI (fMRI) studies have demonstrated that a number of brain regions (cingulate, insula, prefrontal, and sensory/motor cortices) display blood oxygen level-dependent (BOLD) positive activity during swallow. Negative BOLD activations and reproducibility of these activations have not been systematically studied. The aim of our study was to investigate the reproducibility of swallow-related cortical positive and negative BOLD activity across different fMRI sessions. We studied 16 healthy volunteers utilizing an fMRI event-related analysis. Individual analysis using a general linear model was used to remove undesirable signal changes correlated with motion, white matter, and cerebrospinal fluid. The group analysis used a mixed-effects...

139. Antioxidative properties of paraoxonase 2 in intestinal epithelial cells - Précourt, Louis-Philippe; Marcil, Valérie; Ntimbane, Thierry; Taha, Rame; Lavoie, Jean-Claude; Delvin, Edgard; Seidman, Ernest G.; Beaulieu, Jean-François; Levy, Emile
Paraoxonase (PON) family members seem central to a wide variety of human illnesses, but appreciation of their antioxidative function in the gastrointestinal tract is in its infancy. The major objective of the present work is to highlight the role of the ubiquitously expressed PON2 in the small intestine. With use of pLKO lentiviral vector containing short hairpin RNA (shRNA) lentivirus, PON2 expression was knocked down in intestinal Caco-2/15 cells, where antioxidative status, lipid peroxidation, and degree of inflammation were evaluated. As a consequence of PON2 inactivation in the epithelial cells, we observed 1) imbalanced primary and secondary antioxidative responses, characterized...

140. DHRS3, a retinal reductase, is differentially regulated by retinoic acid and lipopolysaccharide-induced inflammation in THP-1 cells and rat liver - Zolfaghari, Reza; Chen, Qiuyan; Ross, A. Catharine
Both retinoid status and inflammation have been shown to control the level of expression of retinoid homeostatic genes. In the present study, DHRS3, previously shown to possess retinal reductase activity, was identified by microarray analysis of THP-1 monocytes as a possible gene target of all-trans-retinoic acid (RA). In these cells, DHRS3 mRNA increased 30- to 40-fold after treatment with ≤20 nM RA for 24 h, while DHRS3 protein also increased. Of several synthetic retinoids tested, only Am580, a RA receptor-α-selective retinoid, increased DHRS3 mRNA expression. The full-length DHRS3 cDNA was cloned from rat liver and subjected to in vitro transcription-translation....

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