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Objectives: Necroptosis, a programmed inflammatory cell death, is involved in the pathogenesis of acute pancreatitis (AP). We compared levels of interleukin (IL)-33 (released upon necroptosis), sST2 (soluble IL-33 receptor), MLKL, RIPK1 and RIPK3 (necroptosis executioner proteins), and proinflammatory cytokines IL-6, TNF and IL-1β at various severity categories and stages of AP., Methods: Plasma from 20 patients with early mild AP (MAP) (symptom onset < 72 h), 7 with severe AP (SAP) without and 4 with persistent organ failure (OF) at sampling, 8 patients with late SAP and 20 healthy controls (HC) were studied by ELISAs., Results: Early sST2 and IL-6 levels predicted the development of SAP and were higher in both MAP and early and late SAP than in HC. RIPK3 levels were higher than in HC in the patients who had or would later have SAP. MLKL levels were associated with the presence of OFs, particularly in the late phase, but were also higher in MAP than in HC., Conclusions: sST2, RIPK3 and IL-6 levels may have prognostic value in AP. Elevated MLKL levels are associated with OF in AP. Better understanding of necroptosis in AP pathophysiology is needed to evaluate whether inhibiting and targeting necroptosis is a potential therapeutic option in AP., (© 2024. The Author(s).)

Introduction: Nutritional deficiencies may occur after bariatric surgery despite supplementation. Fracture risk may also be elevated after bariatric surgery., Objectives: To compare 25-hydroxyvitamin D [25(OH)D], vitamin B12, and albumin serum concentrations in severely obese patients who had undergone either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Fracture data was compared with data for a conservatively treated group of severely obese patients., Methods: We considered 253 RYGB and 142 SG performed between 2007 and 2010. At 1- and 2-year control follow-ups, weight was measured and blood samples were drawn. The control group of 199 obese patients received lifestyle intervention and weight was measured at 1 and 2 years post-intervention between 2002 and 2006. We retrospectively collected fracture data for all patients through the end of 2016., Results: At follow-ups, the mean serum 25(OH)D and albumin levels were within reference ranges and were similar between the RYGB and SG groups. Serum median vitamin B12 level was significantly higher in the SG group compared with the RYBG group, 319 versus 286 pmol/L at 2 years, respectively, p = 0.04. The cumulative risk for fracture was higher in the bariatric groups compared with the control group. The Cox multivariate model showed higher age, bariatric surgery, and lower body mass index (BMI) at the 2-year control increased the risk for fracture after obesity treatment., Conclusion: Vitamin 25(OH)D, B12, and albumin levels were mainly within recommended levels during the 2 years after bariatric surgery. The cumulative fracture risk was higher in bariatric patients.

Background: The laparoscopic Roux-en-Y gastric bypass (LRYGB) has been the gold standard for bariatric surgery, but recently, the laparoscopic sleeve gastrectomy (LSG) has gained popularity. At present, limited data is available on the long-term complications of these two types of surgery. The aim of this retrospective study was to compare the 2-year data about late (more than 30 days after surgery) complications that were treated surgically or endoscopically after LRYGB and LSG operations in a large hospital area with a single patient database., Materials: This was a retrospective, non-randomized, single-center study of 760 (545 LRYGB and 215 LSG) bariatric patients surgically treated between 2008 and 2013 in the Bariatric Surgery Unit of Helsinki University Central Hospital., Methods: The patients were followed for 2 years, and late complications (more than 30 days after surgery) that were surgically and/or endoscopically treated were registered. Weight loss and the risk factors for complications were also monitored., Results: The study found a difference between the LRYGB and LSG patients in a number of late complications treated by both intervention types: surgical intervention were required in 9.4% of LRYGB patients vs. 0.9 of LSG patients, and endoscopic intervention were required by 4.6% of LRYGB patients vs. 1.4% of LSG patients (both p < 0.05). The risk of surgical complications was increased by better weight loss results in 12 months., Conclusions: LRYGB was found to be associated with a greater risk of late complications. If larger databases confirm these results, the trend toward LSG is justified.

Background: Fecal calprotectin is a reliable surrogate marker for inflammatory activity in inflammatory bowel disease (IBD)., Aims: For the noninvasive monitoring of the activity of colonic inflammation, we validated a symptom index suitable for ulcerative colitis and colonic Crohn's disease. By combining the symptom index with a rapid semi-quantitative calprotectin test, we constructed a new activity index based on the highest AUCs, using histological remission as a reference. We also evaluated the correlation of the patient-reported influence of the IBD in the daily life, measured by a VAS, with the inflammation activity., Methods: The disease activity of 72 patients with IBD of the colon was determined by endoscopic activity scores (SES-CD/UCEIS). The patients provided stool samples for determination of calprotectin and filled in a questionnaire about their symptoms during the last week., Results: The results of the symptom index demonstrated a statistically significant correlation with the rapid calprotectin test, histological inflammation activity, and the VAS. No correlations were found between the VAS and calprotectin or the histological inflammation activity. The sensitivity of the combination index to detect active inflammation was slightly superior to fecal calprotectin alone., Conclusion: The new symptom index and the combination index are simple, noninvasive means for distinguishing remission from active inflammation in colonic IBD. With the VAS, we can pick up patients who need psychosocial support because of the disease burden, even if their IBD is in remission.

The current understanding of prophylaxis of pulmonary complications in bariatric surgery is weak., Purpose: The aim of this study was to observe how changes in perioperative and postoperative treatments affect the incidence of pulmonary complications in bariatric patients., Materials: This is a retrospective clinical study of 400 consecutive bariatric patients. The patients, who either underwent a sleeve gastrectomy or a Roux-en-Y gastric bypass, were divided consecutively into four subgroups with different approaches to perioperative treatment., Methods: The first group (patients 0-100) was recovered in the intensive care unit with minimal mobilization (ICU). They had a urinary catheter and a drain. The second group (patients 101-200) was similar to the first group, but the patients used a continuous positive airway pressure (CPAP) device intermittently (ICU-CPAP). The third group (patients 201-300) was recovered on a normal ward without a urinary catheter or a drain and used a CPAP device (ward-slow). The fourth group (patients 301-400) walked to the operating theater and was mobilized in the recovery room during the first 2 h after the operation (ward-fast). CPAP was also used. Primary endpoints were pulmonary complications, pneumonia, and infection, non-ultra descriptus (NUD)., Results: The number of pulmonary complications among the groups was significantly different. A long operation time increased the risk for infection (p < 0.001 95 % CI from 2.02 to 6.59 %)., Conclusions: Operation time increases the risk for pulmonary complications. Changes in perioperative care toward the ERAS protocol may have a positive effect on the number of pulmonary complications.

Background: Few studies have examined weight loss sustainability after sleeve gastrectomy (SG). The purpose of this study was to determine long-term outcome after SG and gastric bypass (GBP) and learn whether preoperative weight loss and binge eating behavior can be used to predict outcome., Materials and Methods: Together, 257 patients (64 % women) were operated, 163 by GBP and 94 by SG. Binge eating was assessed by binge eating scale (BES) and preoperative weight loss was advised to all, including very low-calorie diet for 5 weeks. Postoperative visits took place at 1 and 2 years, and long-term outcome was at median 5 years (range 2.29-6.85). Multivariate linear regression analysis was used to predict outcome at 2-year and long-term control., Results: Median age was 48 years, weight 141.1 kg, and BMI 48.2 kg/m(2). Preoperative weight loss was median 4.9 % before GBP and 3.8 % before SG, P = 0.04. Total weight loss at year one was 24.1 % in GBP and 23.7 % in SG (P = 0.40), at year two 24.4 and 23.4 % (P = 0.26), and at long-term control 23.0 and 20.2 % (P = 0.006), respectively. Weight was analyzed in 93, 88, and 89 % of those alive, respectively. BES did not predict weight outcome, but larger preoperative weight loss predicted less postoperative weight loss at 2 years., Conclusion: On long term, weight loss was better maintained after GBP compared with SG. Binge eating behavior was not a significant predictor, but larger preoperative weight loss predicted less postoperative weight loss for the next 2 years.

Background: Peptic ulcer bleeding (PUB) is a major cause of upper gastrointestinal bleeding. The effect of omeprazole on mucosal repair is unknown., Aims: We studied the effect of omeprazole, nonsteroidal anti-inflammatory agents, and smoking on PUB., Methods: There were 43 PUB patients who received regular or high dose of omeprazole for 72 h. Biopsies from antrum and corpus were taken before and after treatment. Biopsy samples from 20 celiac disease patients worked as controls. The expression of Ki-67, Bcl-2, COX-2, Hsp27, and Hsp70 was analyzed from patients and controls., Results: Bcl-2 expression in PUB patients was lower than in controls. However, Bcl-2 increased significantly from 5.0 (SD 4.5) to 9.1 % (SD 6.7), p = 0.0004, in the antrum after omeprazole. In univariate analysis, a high omeprazole dose caused a more profound increase in Ki-67 expression in the corpus: 35.3 % (SD 54.8) than a regular dose: -10.1 % (SD 40.6), p = 0.022. In multivariate analysis, Ki-67 decreased significantly in the corpus between the pre- and posttreatment period (p = 0.011), while a high omeprazole dose (p = 0.0265), the use of NSAIDs (p = 0.0208), and smoking (p = 0.0296) significantly increased Ki-67 expression. Bcl-2 in the corpus increased significantly (p = 0.0003) after treatment., Conclusions: Our findings suggest that Bcl-2 may be an important factor in the pathogenesis of a peptic ulcer and PUB. In addition, high-dose omeprazole increased the expression of Ki-67, which may enhance the healing process of a peptic ulcer.

Background: Preoperative ultrasonography (US) prior to laparoscopic Roux-en-Y gastric bypass (LRYGBP) aimed to find possible gallstones. The aim of this study was to evaluate the reliability of the US in evaluating the size and consistency of the left lobe of the liver., Methods: One hundred LRYGBP and LSG were performed in our new bariatric surgery unit by two surgeons. All patients underwent preoperative US to evaluate the size and consistency of the left lobe of the liver. A consultant radiologist reviewed the US findings, which were then compared to the intraoperative findings., Results: The mean preoperative body mass index was 49. All patients had co-morbidities. The intraoperative evaluation showed an enlarged left lobe of the liver in 23 patients, whereas the US found enlargement only in eight patients, but revealed eight false positives. In the intraoperative evaluation, fatty liver was observed in five patients, only four of whom were shown in the US, but US revealed 77 false positives. In evaluating the size of the left lobe, US had 35% sensitivity, 90% specificity, 65% false negative rate (FNR) and 10% false positive rate (FPR). In evaluating the consistency, US had 80% sensitivity, 18% specificity, 20% FNR and 82% FPR., Conclusion: Preoperative US is unreliable in evaluating the size and consistency of the left lobe of the liver prior to LRYGBP and LSG and has limited prognostic value for surgical complications and complexity of surgery.

Background: Bariatric surgery has shown to be safe for patients over 60 years with good results especially considering resolving of comorbidities. Sleeve gastrectomy is considered to be safer than gastric bypass (GBP) and more effective than gastric banding with less adverse symptoms. Weight loss may be more modest than after GBP, but the effect on vitamins may also be milder., Methods: Since 2007, we collected prospectively 12-month follow-up data from 55 sleeve gastrectomy patients of whom 12 were over 59 years of age. Vitamin and calcium supplements were used postoperatively. The recovery from the operation was recorded during hospital stay, at 1- and 12-month follow-up visits using a standard protocol including laboratory tests. The results between patients over and under 59 years were compared., Results: The preoperative weight and weight loss were comparable between the groups. Operation time was shorter and hospital stay was longer for older patients, p = ns. There was no operative mortality. Early major complications were seen more often in the older age group, 42% vs 9% (p = 0.02), but late complications were more common in younger patients, 17% vs 44%, p = ns. Early complications were mostly bleedings, which did not lengthen the hospital stay, neither were re-operations nor endoscopic procedures needed. Excess weight loss and resolving of comorbidities after 12 months was comparable between the groups. However, vitamin deficiencies and hypoalbuminemia were more common in the older age group, 42% and 23% for vitamins and 44% and 29% for proteins, p = ns. The older patients had more adverse effects related to surgery, 25% vs 9%, and younger had more adverse psychiatric effects, p = ns., Conclusions: Sleeve gastrectomy is effective and safe for older bariatric patients. Weight loss is comparable to younger patients and enough to resolve the comorbidities in most of the patients. With standardized nutritional supplementation, the older patients had more often vitamin deficiencies and hypoalbuminemia. Although operative treatment of older bariatric patients is safe, their postoperative care is demanding considering vitamins and protein.

We have previously shown that ethanol (EtOH) induces protective NF-kappaB activation in gastric surface epithelial cells. This study investigates the defense systems in rat gastric mucosal cells (RGM-1) exposed simultaneously to EtOH and taurocholate (TC) or acetylsalicylic acid (ASA). Simultaneous exposure to ASA and EtOH increased EtOH-induced caspase-3 activity and decreased cell viability, indicating synergetic damaging action. Simultaneous exposure to TC (5 mM) with EtOH (5%) increased EtOH-induced NF-kappaB activation, opposing EtOH-induced decrease in cell membrane integrity and in cell viability as shown by decreasing RelA expression with siRNA technique. Low doses of TC decreased the EtOH (5%) induced caspase-3 activity independently from NF-kappaB pathway and inhibited EtOH-induced decrease in caspase-3 precursor protein levels, also indicating the inhibition of caspase-3 pathway. The TC (5 mM)-induced protection in EtOH exposed tissues seems to have two distinct pathways, inhibition of apoptosis and enhancement of NF-kappaB signaling.

We have here elucidated whether ulcerogenic agents affect the production of NO and reactive oxygen species (ROS). The ulcerogenic agents dose dependently induced NO and ROS production in mouse gastric epithelial cells. Taurocholate (TC, 5 mM) exposure did not affect cell viability, but it increased inducible nitric oxide synthase (iNOS) expression, NO production, ROS production, and epithelial permeability. Epithelial permeability was inhibited with NOS inhibitors or antioxidants. Oxidative stress induced by acetylsalicylic acid (ASA) and ethanol was not inhibited with NOS inhibitors. ASA induced ROS production even at low concentrations (1 mM), which did not affect cell viability. Ethanol-induced ROS production was linked to cell viability, suggesting direct oxidative stress caused by ethanol. Taurocholate-induced NO signaling and the ensuing production of ROS might contribute to initiation of defensive or adaptive cellular mechanisms. ASA-induced ROS signaling might have similar effects, whereas ethanol induced direct oxidative stress, having an influence on cell viability.

We have elucidated the role of different ion transporters and epidermal growth factor(EGF) during luminal acid exposure in primary cultured rabbit surface epithelial cells by measuring intracellular calcium and pH. Amiloride, DIDS, or sodium or bicarbonate substitutions were used to inhibit ion transport. During luminal acid exposure the dominant intracellular pH regulator is the Na+/H+ antiport, and bicarbonate transport has only a secondary role, which is uncovered as the Na+/H+ function fails. The decrease in intracellular pH caused by luminal acid was significantly smaller in serosal EGF-treated epithelia than in controls. This defensive function of EGF was abolished by verapamil, BAPTA, and calmidazolium but not by TMB-8. EGF increased intracellular calcium, which was prevented by verapamil but not by TMB-8. EGF enhances gastric epithelial defense against luminal acid by inducing intracellular calcium signaling via plasma membrane verapamil-sensitive calcium channels and thereby enhancing the function of the Na+/H+ antiport.

Cell volume regulation was investigated in gastric surface epithelial cells during hypertonic conditions. Isolated Necturus antral mucosa was perfused on the serosal side with Ringer's solution (pH 7.25, 95%O2/5%CO2) and on the mucosal side successively with 150-500 mM NaCl. Amiloride, ouabain, and bumetanide were used to experimentally inhibit Na+/H+, Na+/K+ ATPase or Na+-K+-2Cl- ion transporters. Intracellular sodium activity and cell volume changes were measured with liquid sensor microelectrodes. The increase in intracellular sodium activity caused by luminal hyperosmolar exposure was mainly due to cell shrinkage. Inhibition of Na+/K+ ATPase or Na+-K+-2Cl- cotransporter increased hyperosmotic cell shrinkage (-52 +/- 5%, -85 +/- 19%, and -77 +/- 9% for control, ouabain, and bumetanide, respectively). Inhibition of Na+/K+ ATPase increased intracellular sodium activity (from 18 +/- 4 to 52 +/- 12 mM). Cell volume regulation in gastric epithelial surface cells during mucosal hyperosmolar exposure is maintained by the basolateral Na+-K+-2Cl- cotransporter, while Na+/K+ ATPase maintains sodium balance, but Na+/H+ antiport seems to have a less important role.

Ethanol is a well-established "barrier breaker" in gastric mucosa, but its detailed effects at the cellular level remain unclear. We have previously shown that the intracellular free calcium concentration is increased, gap junctions are closed, and cell volume is decreased after exposure to 5% (v/v) ethanol in primarily cultured rabbit gastric epithelial cells. Rat gastric mucosal (RGM) cells were grown to confluence on a coverslip or on a filter membrane. Gap junctional diffusion was measured in 5-carboxyfluorescein-loaded cells by bleaching a small area with a laser and measuring the recovery with confocal microscope. Intracellular calcium was measured spectrofluorometrically in fura-2-loaded cells. For cell volume measurements the cell monolayer was loaded with calcein and imaged along the Z-axis with a confocal microscope. The changes in fluorescence intensity were intercepted as a measure of cell volume change. TMB-8 was used to inhibit intracellular calcium release and lanthanum to block plasma membrane calcium selective ion channels, while BABTA served as an intracellular calcium chelating agent. Results showed that ethanol (7.5%, v/v) exposure increased intracellular calcium from 69 +/- 7 to 142 +/- 11 nM (N = 5; P < 0.05), decreased cell volume by -23 +/- 5% (N = 8; P < 0.05), and induced gap junction closure (fluorescence recovery from 37 +/- 9 to 15 +/- 3%; N = 6; P < 0.05). A serosal potassium channel blocker, quinine, almost completely prevented the ethanol-induced cell volume decrease (from -23 +/- 5 to -3 +/- 3%), suggesting that opening of basolateral potassium channels underlies cell shrinkage. BABTA inhibited completely (from 35 +/- 3 to 39 +/- 4 nM; N = 6; P < 0.05), and TMB-8 + lanthanum partially (from 60 +/- 6 to 92 +/- 12 nM; N = 6; P < 0.05), the ethanol-induced intracellular calcium increase. BABTA also abolished the ethanol-induced volume decrease (from -23 +/- 5 to 1 +/- 4%; N = 6; P < 0.05), while TMB-8 + lanthanum had a lesser effect on it (from -23 +/- 5 to -11 +/- 3%; N = 9; P < 0.05). They also abolished the closure of gap junctions induced by ethanol (fluorescence recovery, 38 +/- 5% for BABTA and 30 +/- 4% for TMB-8 + lanthanum). We conclude that luminal ethanol opens basolateral calcium-dependent potassium selective channels with resultant shrinkage of the cells and blocks the intercellular gap junctions. These actions are mediated by intracellular calcium signaling.

Ethanol is a well-established "barrier breaker" in gastric mucosa, but its detailed effects at the cellular level remain unclear. We have previously shown that the intracellular free calcium concentration is increased, gap junctions are closed, and cell volume is decreased after exposure to 5% (v/v) ethanol in primarily cultured rabbit gastric epithelial cells. Rat gastric mucosal (RGM) cells were grown to confluence on a coverslip or on a filter membrane. Gap junctional diffusion was measured in 5-carboxyfluorescein-loaded cells by bleaching a small area with a laser and measuring the recovery with confocal microscope. Intracellular calcium was measured spectrofluorometrically in fura-2-loaded cells. For cell volume measurements the cell monolayer was loaded with calcein and imaged along the Z-axis with a confocal microscope. The changes in fluorescence intensity were intercepted as a measure of cell volume change. TMB-8 was used to inhibit intracellular calcium release and lanthanum to block plasma membrane calcium selective ion channels, while BABTA served as an intracellular calcium chelating agent. Results showed that ethanol (7.5%, v/v) exposure increased intracellular calcium from 69± 7 to 142± 11 nM (N = 5; P < 0.05), decreased cell volume by -23± 5% (N = 8; P < 0.05), and induced gap junction closure (fluorescence recovery from 37± 9 to 15± 3%; N = 6; P < 0.05). A serosal potassium channel blocker, quinine, almost completely prevented the ethanol-induced cell volume decrease (from -23± 5 to -3± 3%), suggesting that opening of basolateral potassium channels underlies cell shrinkage. BABTA inhibited completely (from 35± 3 to 39± 4 nM; N = 6; P < 0.05), and TMB-8 + lanthanum partially (from 60± 6 to 92± 12 nM; N = 6; P < 0.05), the ethanol-induced intracellular calcium increase. BABTA also abolished the ethanol-induced volume decrease (from -23± 5 to 1± 4%; N = 6; P < 0.05), while TMB-8 + lanthanum had a lesser effect on it (from -23± 5 to -11± 3%; N = 9; P < 0.05). They also abolished the closure of gap junctions induced by ethanol (fluorescence recovery, 38± 5% for BABTA and 30± 4% for TMB-8 + lanthanum). We conclude that luminal ethanol opens basolateral calcium-dependent potassium selective channels with resultant shrinkage of the cells and blocks the intercellular gap junctions. These actions are mediated by intracellular calcium signaling.

Several growth factors and cytokines are involved in regulation of the immediate repair of gastrointestinal mucosa, a process also called restitution. Few data exist on the effect of inflammation on this process using an explant model, where the folded basal lamina is included. The aim of the present study was to investigate the effect of simulated inflammation on restitution and on concomitant proliferation and apoptosis in isolated guinea pig gastric mucosa. Paired gastric mucosae were mounted in Ussing chambers (37 degrees C) and a superficial injury was induced (1.25 M NaCl/5 min) followed by a 4-hr restitution (pH 7.3-7.5). During perfusion, simulated inflammation was induced (with 0.5 or 5.0 ng/ml IL-1beta or with activated polymorphonuclear [PMN] cells). The PI (proliferative index) and AI (apoptotic index) are expressed as the number of Mib-1- or Bax-immunopositive cells per 300 foveolar cells, respectively. The mean recovery of electrophysiological resistance of tissues (R) after injury and exposure to serosal IL-1beta during restitution was 95.2 +/- 5.3% (mean +/- SD), whereas the value for control tissues was 89.6 +/- 6.9% (P = 0.016; N = 9). The mean recovery of R in tissues exposured to activated serosal PMN cells during restitution was 97.6 +/- 2.7%, whereas the value for unexposed control tissues was 93.8 +/- 2.9 (P = 0.004; N = 9). The enhancing effect of PMN cells was partially eliminated by serosal anti-ICAM, whereas serosal cytochalasin D abolished the process completely. The PI of tissues exposed to serosal PMN cells was 34.6 +/- 17.3, whereas the value for unexposed controls was 24.7 +/- 15.5 (P = 0.04; N = 5). The corresponding AI values were 17.0 +/- 2.8 and 12.0 +/- 5.7, respectively (NS; N = 4). Simulated inflammation either with serosal IL-1beta or with activated PMN cells enhances restitution and proliferation, whereas their effect on AI is only suggestive. Exogenous serosal anti-ICAM modulates restitution, whereas cytochalasin D abolishes it completely, suggesting that the structural signaling system including focal adhesions and cytoskeleton plays a significant role in the regulation of restitution.

Ethanol is a well-established "barrier breaker" in gastric mucosa, but its effects at the cellular level remain to be elucidated. Isolated Necturus antral mucosa was exposed luminally to 5-15% (v/v) ethanol at pH 3.0. Apical, basolateral, shunt, and internal resistances in surface epithelium were measured using 2-D cable analysis. Cell volume changes were determined from tetramethylammonium-loaded surface cells. Low luminal ethanol (5%) decreased basolateral resistance, presumably by opening of K+ channels, since this decrease was partially inhibited by the K+ channel blocker, quinine. Low ethanol decreased also epithelial cell volume, which was opposed by quinine, suggesting that efflux of intracellular K+ underlies this shrinkage. High luminal ethanol (15%) markedly decreased shunt and apical cell membrane resistances, and partially closed gap junctions as judged from increased epithelial internal resistance. Opening of basolateral K+ channels with resultant epithelial cell shrinkage might be among the initial steps in ethanol induced gastric injury. The changes in intraepithelial resistances provoked by stronger ethanol probably reflect emerging structural epithelial damage.

Superficial gastric mucosal injury is rapidly repaired by epithelial cell migration. This study aims to characterize the intracellular signal transduction pathways underlying the repair process. Primary monolayer cultures of rabbit gastric epithelial cells were wounded. The measured spontaneous cell migration speed at the edge of the wound was 457+/-89 microm/24 hr. Epidermal growth factor stimulated and genistein (receptor tyrosine protein kinase inhibitor) inhibited cell migration significantly. Down-regulation of protein Kinase C (PKC) with long-term phorbol 12-myristate 13-acsetate or inhibition with calphostin-C significantly inhibited cell migration. Blocking of Ca2+ channels with verapamil and endogenous Ca2+ release with TMB-8 or inhibition of the Ca2+/calmodulin complex with calmidazolium likewise significantly inhibited migration speed and also abolished the rise of [Ca2+]i, which was measured in migrating cells. Modulation of the cAMP-PKA pathway or prostaglandin synthesis had no influence on cell migration. Gastric epithelial cell migration implies activation of receptor tyrosine kinase. It is associated with increased [Ca2+]i and requires an intact Ca2+/calmodulin complex. Intact PKC activity also is needed.

This study investigates whether topical prostaglandins protect isolated gastric mucosa against injury provoked by acidified "barrier-breaking" agents. Intracellular pH (pHi), apical cell membrane potential (Vcm) and intraepithelial resistances in isolated Necturus antral mucosa were measured using double-barreled liquid sensor microelectrodes. Topical PGE, treatment protected the antral mucosa against acidified taurocholate-induced injury, reducing significantly (P<0.05) intracellular acidification (pHi from 7.39+/-0.05 to 7.08+/-0.08 vs. from 7.30+/-0.02 to 6.62+/-0.15), and opposing significantly the changes in Vcm (hyperpolarization followed by depolarization), and completely abolishing the decrease in transmembrane resistance (Rt from 702+/-37 to 723+/-39 Ohms x cm2 vs. from 721+/-34 to 270+/-105 Ohms x cm2). Also the ratio of apical and basolateral membrane resistances (Ra/Rb) remained at a significantly higher level in PGE2-treated tissues. In contrast, PGE2 treatment had no protective influence on the changes of the respective parameters in acidified ethanol or acetylsalicylic acid injured mucosas. Topical prostaglandin E2 protects isolated gastric mucosa against acidified taurocholate, but not against ethanol- or acetylsalicylic acid-induced injury.

Systemic metabolic alkalosis and topical prostaglandins protect the gastric mucosa against luminal acid. This study investigates whether this protection is mediated by increased epithelial HCO3(-) secretion with resultant alkalization of the pre-epithelial mucus-HCO3(-) buffer layer. surface pH of chambered ex vivo rat gastric epithelium was measured with liquid sensor pH microelectrodes during luminal perfusion of increasing acidities (0, 10, 30, 50, 100 mM HCL). The experimental groups were: (1) control, (2) topical 16,16-dimethyl-PGE2 treatment, (3) high-HCO3(-) metabolic alkalosis, and (4) low HCO3(-) respiratory alkalosis. The gastric mucosa of PGE2-treated and high-HCO3(-) alkalotic rats tolerated significantly better luminal acid than that of controls, but the tolerance of low-HCO3(-) alkalotic rats was significantly impaired. There was a significant correlation between arterial HCO3(-) concentration (but not arterial pH) and surface pH (r = 0.81, P < 0.01). This suggests that the gastric mucosa against luminal acid are, at least in part, mediated by enhanced buffer capacity of the pre-epithelial mucus-HCO3(-)layer.

The tolerance of the duodenal mucosa to luminal acid was investigated by measuring with a liquid sensor pH microelectrode technique the epithelial surface pH (pHs) and subepithelial tissue pH (pHt) in rat proximal (duodenal bulb, Brunner gland area) and distal duodenum exposed to luminal acid. Under basal conditions, pHs was roughly equal in both parts of the duodenum; proximal duodenum, 7.40 +/- 0.14 (mean +/- SEM) at the villus tip and 7.54 +/- 0.16 at the depth of crypt; distal duodenum, 7.46 +/- 0.19 and 7.55 +/- 0.09, respectively. Yet, exposure of the mucosa to luminal acid (10 mM HCl) provoked a significantly lesser decrease of pHs (0.25 +/- 0.13 vs 0.42 +/- 0.12 pH units) in the proximal duodenum, suggesting that the response of epithelial HCO3 secretion to luminal acid is stronger in that part of the duodenum. Further, the initial acidification of pHs was followed in the proximal duodenum by a secondary alkalinization of pHs, leading to normalization of pHs, which may suggest activation of compensatory protective mechanisms. pHt at the villus tip was likewise roughly equal in both parts of duodenum (7.29 +/- 0.05 vs 7.17 +/- 0.04), but, again, acidification of the luminal perfusate progressively from 10 to 100 mM HCl induced a much earlier and significantly more profound acidification in the distal than in the proximal duodenum. The possible contribution of Brunner glands to the greater mucosal tolerance to acid in the proximal duodenum was assessed by investigating whether stimulation or inhibition of Brunner gland secretion modulates the response of the duodenal mucosa to acid.(ABSTRACT TRUNCATED AT 250 WORDS)