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Stuart J Spechler

Publications and source records attributed to Stuart J Spechler.

18 recordsLinked to original sources
PubMed2006

Surgical bypass versus endoscopic stenting for malignant gastroduodenal obstruction: a decision analysis.

The treatment options for palliating malignant gastroduodenal obstruction include open gastrojejunostomy (OGJ), laparoscopic gastrojejunostomy (LGJ), and endoscopic stenting (ES). The aim of this study was to compare the clinical outcomes and costs among ES, OGJ, and LGJ in patients who present with gastroduodenal obstruction from advanced upper gastrointestinal tract cancer. We designed a model for patients with malignant gastroduodenal obstruction. We analyzed success rates, complication rates and costs of the three treatment modalities: ES, OGJ, and LGJ. Baseline outcomes and costs were based on published reports. Success was defined as no major procedure-related and long-term complications over a 1-month period. Failure of therapy was defined as recurrent symptoms or death due to a procedural complication. Sensitivity analyses and cost-effectiveness analyses for the various strategies were performed. ES resulted in the lowest mortality rate and the lowest cost of the three treatment options analyzed. Mortality in the OGJ group was 2.1 times that in the ES cohort and 1.8 times that in the LGJ cohort. Sensitivity analyses confirmed ES as the dominant strategy. In conclusion, ES is the preferred treatment for palliation of duodenal obstruction due to advanced upper gastrointestinal tract cancer.

Decision Support Techniques↗
PubMed2006

All trans-retinoic acid induces apoptosis via p38 and caspase pathways in metaplastic Barrett's cells.

Retinoids such as all trans-retinoic acid (ATRA) have been used as chemopreventive agents for a number of premalignant conditions. To explore a potential role for retinoids as chemopreventive agents for Barrett's esophagus, we studied ATRA's effects on apoptosis in a nonneoplastic, telomerase-immortalized, metaplastic Barrett's cell line. We treated the Barrett's cells with ATRA in the presence and absence of inhibitors to p53 (pSRZ-siRNA-p53), p38 (SB-203580 and p38 siRNA), and the caspase cascade (z-Val-Ala-Asp-fluoromethyl ketone). We determined the effects of ATRA and the various inhibitors on apoptosis using cell morphology, terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling staining, cleaved caspase-3 immunofluorescence, and Annexin V staining. We also determined how ATRA in the presence and absence of the inhibitors affected apoptosis following low-dose UV-B irradiation. ATRA induced apoptosis and increased the expression of p53 protein in a dose-dependent fashion. The apoptotic effect of ATRA was abolished by treatment with inhibitors of both p38 and caspase, but not by p53 interfering RNA (RNAi). Inhibition of p38 also prevented expression of cleaved caspase-3, suggesting that ATRA activates p38 upstream of the caspase cascade. We found that ATRA sensitized immortalized Barrett's cells to apoptosis induced by low-dose UV-B irradiation via a similar mechanism. ATRA induces apoptosis in Barrett's epithelial cells and sensitizes them to apoptosis induced by UV-B irradiation via activation of p38 and the caspase cascade, but not through p53. This study elucidates molecular pathways whereby retinoid treatment might prevent carcinogenesis in Barrett's metaplasia and suggests a potential role for the use of safer retinoids for chemoprevention in Barrett's esophagus.

Apoptosis↗
PubMed2006

Gastric and esophageal pH in patients with Barrett's esophagus treated with three esomeprazole dosages: a randomized, double-blind, crossover trial.

BACKGROUND: It has been suggested that patients with Barrett's esophagus (BE) are unusually resistant to the antisecretory effects of proton pump inhibitors (PPIs). OBJECTIVES: To compare intragastric and intraesophageal acidity in patients with BE receiving esomeprazole 40 mg three times daily (t.i.d.), esomeprazole 40 mg twice daily (b.i.d.), and esomeprazole 20 mg t.i.d. METHODS: In this randomized, double-blind, three-way crossover study, patients with long-segment BE received each of the three esomeprazole dosages for 5 days separated by 10-14-day washout periods. Intragastric and intraesophageal pHs were measured for 24 h on day 5. RESULTS: Among 31 patients with evaluable pH data, intragastric pH was >4.0 for 88.4%, 81.4%, and 80.4% of day 5 after treatment with esomeprazole 40 mg t.i.d., 40 mg b.i.d., and 20 mg t.i.d., respectively. Esomeprazole 40 mg t.i.d. was significantly more effective than the other dosages (p < 0.01). Intraesophageal pH was <4.0 for mean values of <5% of the monitoring period with all the three dosing regimens, but esophageal pH remained <4.0 for >5% of the time in 16%, 23%, and 19% of patients receiving esomeprazole 40 mg t.i.d., 40 mg b.i.d., and 20 mg t.i.d., respectively. All dosages were well tolerated. CONCLUSIONS: All the three esomeprazole dosages significantly decreased intragastric acidity and reduced esophageal acid exposure to mean normal values in the total group of patients with BE. However, abnormal esophageal acid exposure continued in 16-23% of patients despite the significant decrease in gastric acidity. These results suggest that the apparent "PPI resistance" described in patients with BE may be caused by their profound reflux diathesis rather than by gastric resistance to the antisecretory effects of PPIs.

Aged↗
PubMed2006

Thermal ablation of Barrett's esophagus: a heated debate.

A study reported in this issue of the American Journal of Gastroenterology has explored the efficacy of high-power argon plasma coagulation (APC) for the eradication of nonneoplastic Barrett's epithelium. Complete eradication was achieved in 77% of 48 patients, with a 10% rate of major complications including hemorrhage, esophageal stricture, and esophageal perforation. Although these observations indicate that high-power APC can eradicate Barrett's epithelium in some patients, it is not clear that this expensive and hazardous therapy conveys any clinical benefit. Even if one makes the substantial leap of faith that APC can decrease the risk of cancer in Barrett's esophagus, that risk is so small for patients without dysplasia that the number needed to treat is unacceptably large. Available data do not support the routine application of endoscopic ablative therapy for patients who have Barrett's esophagus without dysplasia.

Argon↗
PubMed2005

Gain of allelic gene expression for IGF-II occurs frequently in Barrett's esophagus.

The IGF-II gene normally exhibits genomic imprinting, a DNA modification that allows the expression of only one of the two inherited alleles. With loss of imprinting, there is a gain of allelic gene expression (GOAGE) due to IGF-II being expressed by both alleles. GOAGE for IGF-II has been demonstrated in a number of malignancies and in normal epithelia surrounding malignancies, but not in epithelia without associated neoplasia. We hypothesized that nonneoplastic Barrett's epithelium might have GOAGE for IGF-II that could facilitate its progression to neoplasia. Endoscopic biopsies were obtained from metaplastic esophageal, normal gastric, and normal duodenal epithelia from 43 patients with Barrett's esophagus. Genomic DNA were analyzed using PCR followed by ApaI restriction enzyme digestion or allele-specific PCR to identify an ApaI polymorphism of IGF-II. cDNA from patients with the ApaI polymorphism were analyzed for IGF-II GOAGE using exon connection PCR, followed by a secondary nested PCR and ApaI restriction enzyme digestion. We found that 13 (30%) of 43 samples of Barrett's metaplasia contained the ApaI polymorphism and were thus informative for IGF-II, and sufficient material was available for GOAGE analysis in 9 of those 13 cases. GOAGE for IGF-II was demonstrated in five (56%) of those nine cases. All patients with GOAGE in Barrett's metaplasia also demonstrated GOAGE in the gastric and duodenal epithelia. In contrast, patients without GOAGE in Barrett's metaplasia also had no GOAGE in their gastric and duodenal epithelia. We conclude that in patients with Barrett's esophagus, GOAGE for IGF-II is found frequently in the metaplastic esophageal epithelium as well as in normal gastric and duodenal epithelia.

Alleles↗
PubMed2005

Bile salt exposure increases proliferation through p38 and ERK MAPK pathways in a non-neoplastic Barrett's cell line.

Bile reflux has been implicated in the neoplastic progression of Barrett's esophagus (BE). Bile salts increase proliferation in a Barrett's-associated adenocarcinoma cell line (SEG-1 cells) by activating ERK and p38 MAPK pathways. However, it is not clear that these findings in cancer cells are applicable to non-neoplastic cells of benign BE. We examined the effect of bile salts on three human cell lines: normal esophageal squamous (NES) cells, non-neoplastic Barrett's cells (BAR cells), and SEG-1 cells. We hypothesized that bile salt exposure activates proproliferative and antiapoptotic pathways to promote increased growth in BE. NES, BAR, and SEG-1 cells were exposed to glycochenodeoxycholic acid (GCDA) at a neutral pH for 5 min. Proliferation was measured by Coulter counter cell counts and a 5-bromo-2'-deoxyuridine (BrdU) incorporation assay. GCDA-induced MAPK activation was examined by Western blot analysis for phosphorylated ERK and p38. Apoptosis was measured by TdT-mediated dUTP nick-end labeling and annexin V staining after GCDA and UV-B exposure. Statistical significance was determined by ANOVA. NES cells exposed to 5 min of GCDA did not increase cell number. In BAR cells, GCDA exposure increased cell number by 31%, increased phosphorylated p38 and ERK levels by two- to three-fold, increased BrdU incorporation by 30%, and decreased UV-induced apoptosis by 15-20%. In conclusion, in a non-neoplastic Barrett's cell line, GCDA exposure induces proliferation by activation of both ERK and p38 MAPK pathways. These findings suggest a potential mechanism whereby bile reflux may facilitate the neoplastic progression of BE.

Adenocarcinoma↗
PubMed2005

Acid increases MAPK-mediated proliferation in Barrett's esophageal adenocarcinoma cells via intracellular acidification through a Cl-/HCO3- exchanger.

Abundant epidemiological evidence links acid reflux to adenocarcinoma in Barrett's esophagus, but few studies have examined the cellular mechanisms by which acid promotes this neoplastic progression. We hypothesized that extracellular acid exposure causes intracellular acidification that triggers MAPK signaling and proliferation in Barrett's epithelial cells. We tested that hypothesis in a Barrett's-derived esophageal adenocarcinoma cell line (SEG-1). SEG-1 cells were exposed to varying concentrations of acid, and intracellular pH (pH(i)) was measured by 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein microfluorimetry. After acid exposure, ERK and p38 MAPK activation were measured by Western blot analysis and an immune complex kinase assay. Proliferation was measured by Coulter counter cell counts and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide incorporation assay. Exposure of SEG-1 cells to solutions with a pH between 3 and 6.5 caused a rapid, reversible decrease in pH(i) to a level approximately equal to extracellular pH. Acid exposure caused a rapid activation of both ERK and p38 MAPKs and also resulted in pH-dependent increases in cell number, with a maximum increase of 41% observed at pH 6.0. The MAPK activation and proliferation in SEG-1 cells induced by acid exposure could be blocked by pretreatment with disodium 4,4'-diisothiocyanatostilbine-2,2'-disulfonate (DIDS), which prevents intracellular acidification by inhibiting the Cl(-)/HCO(3)(-) exchanger. In conclusion, in SEG-1 cells, extracellular acid exposure causes intracellular acidification, which activates MAPK and causes proliferation. The magnitude of these effects is pH dependent, and the effects can be inhibited by preventing intracellular acidification with DIDS.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2005

Information assimilation and distribution challenges and goals for real and virtual journals.

The distribution of biomedical information was transfigured over three centuries ago with the introduction of scientific journals. This enabled the widespread dissemination of data to global audiences and greatly facilitated not only the advance of science but amplified the interaction between investigators despite their different locations. This process continued to expand in a linear fashion prior to the emergence of the Internet. The latter system has prompted a phenomenal augmentation of information accessibility, and its ever-expanding use has resulted in an exponential increase in the demand for digital technology and online resources. This technology has achieved unprecedented acceptance in the scientific domain and enabled publishers to expeditiously produce and distribute journal contents online. Such unparalleled access to information has sparked incendiary debate within the scientific community and among journal publishers in regard to numerous issues. It is thus much debated as to who has the right to "own" or control intellectual property, whether information should be made freely available to the online global community, how to gauge the legitimacy and authenticity of published research, and the need to reexamine the feasibility and profitability of paper journals in consideration of the digital, online formats that continue to gain popularity. To assess the current status of the situation, a meeting of journal editors, research scientists, and publishing executives was held in Constance, Germany, on June 26, 2004, to discuss these issues and formulate strategies and recommendations for the future of biomedical publishing. Herewith we provide a summation (manifesto) of the meeting's proceedings and provide a consensus opinion with the aim of illuminating the subject and also proposing some putative solutions for the major challenges that currently confront the scientific and publishing community.

Forecasting↗
PubMed2005

Fundoplication and the risk of esophageal cancer in gastroesophageal reflux disease: a Veterans Affairs cohort study.

BACKGROUND AND AIMS: It has been proposed that fundoplication can reduce the risk of esophageal cancer in patients with gastroesophageal reflux disease (GERD). In this cohort study, we assessed the effect of fundoplication on the incidence of esophageal cancer. METHODS: We identified all Veterans Affairs (VA) patients with GERD who had fundoplication between 1986 and 1990 and matched (1-2) to controls with GERD and no fundoplication and to controls with no GERD. We calculated incidence rates for esophageal cancer through October 2002 and examined the effect of fundoplication on the risk of esophageal cancer using Kaplan-Meier survival analysis and Cox proportional hazard analysis. We calculated and adjusted for the propensity score for receiving fundoplication. RESULTS: We identified 946 patients who had fundoplication, 1,892 patients who had GERD without fundoplication, and 5,676 patients with no GERD. The mean age was 55 yr and 97.5% were men in all three groups. During a follow-up of 11,156 patient-years (PY), there were eight cases of esophageal cancer (72/100,000) in the fundoplication group. During a follow-up of 20,115 PY, there were eight cases of esophageal cancer (40/100,000) in the GERD without fundoplication group. During a follow-up of 59,439 PY, no patients in the group with no GERD developed esophageal cancer. The Kaplan-Meier analysis showed no significant difference in cumulative esophageal cancer rates between the fundoplication group and the GERD no-fundoplication group. The adjusted hazard ratio of esophageal cancer with fundoplication was 1.88 (95% CI: 0.70-5.03). CONCLUSIONS: GERD is a risk factor for esophageal cancer, but there is insufficient evidence that fundoplication reduces that risk.

Adult↗
PubMed2005

Differences in ERK activation in squamous mucosa in patients who have gastroesophageal reflux disease with and without Barrett's esophagus.

OBJECTIVES: In some patients with gastroesophageal reflux disease (GERD), the reflux-damaged esophageal squamous epithelium heals through the process of intestinal metaplasia (resulting in Barrett's esophagus) rather than through the regeneration of more squamous cells. We hypothesized that squamous epithelium in Barrett's esophagus might have abnormalities in activation of the extracellular-regulated kinases 1 and 2 (ERK1/2) signaling pathway that may facilitate esophageal repair through metaplasia in response to acid-induced injury. METHODS: Endoscopic biopsies were taken from distal esophageal squamous mucosa in patients who had GERD with and without Barrett's esophagus and in controls, before and after esophageal perfusion with 0.1 N HCl acid. Basal ERK1/2 phosphorylation, acid-induced ERK1/2 activity and phosphorylation, and localization of phosphorylated ERK1/2 were determined using immunoblotting, Western blotting, and immunohistochemistry. RESULTS: Compared to patients with Barrett's esophagus, patients with GERD exhibited significantly lower baseline levels of phosphorylated ERK1/2 expression (35 +/- 4%vs 90 +/- 21% control, p= 0.01) Acid exposure significantly increased ERK1/2 activity (346.6 +/- 51.90 to 446.8 +/- 62.44 RIU, p= 0.02) and phosphorylation (3.55 +/- 1.26 to 4.49 +/- 1.25 [ratio phospho/total ERK], p= 0.01) in the squamous mucosa of GERD patients, but not in those with Barrett's esophagus or in controls. CONCLUSIONS: Between patients with Barrett's esophagus and patients with uncomplicated GERD, there are significant differences in baseline levels and in acid-induced activation of ERK1/2 in esophageal squamous epithelium. To our knowledge, this is the first description of a molecular, phenotypic feature that distinguishes the esophageal squamous mucosa of GERD patients with and without Barrett's esophagus.

Adult↗
PubMed2004

Acid increases proliferation via ERK and p38 MAPK-mediated increases in cyclooxygenase-2 in Barrett's adenocarcinoma cells.

Cyclooxygenase-2 (COX-2) has been linked to neoplastic progression in Barrett's esophagus. Acid exposure has been shown both to activate the MAPK pathways and to increase COX-2 protein expression in Barrett's metaplasia, but it is not known whether these effects are interrelated. We hypothesized that acid-induced activation of the MAPK pathways mediates an increase in COX-2 expression in Barrett's esophagus, and we tested this hypothesis in a Barrett's-associated adenocarcinoma cell line (SEG-1). We exposed SEG-1 cells to acidic or neutral media in the presence and absence of two MAPK inhibitors: U-0126 (an ERK inhibitor) or SB-203580 (a p38 inhibitor). We quantitated COX-2 protein levels using an enzyme immunometric assay and COX-2 mRNA levels using real-time PCR. We also determined how acid affects the activity of the COX-2 promoter and mRNA stability. Compared with SEG-1 cells exposed to neutral media, acid-exposed cells exhibited a 2.8-fold increase in COX-2 mRNA levels within 30 min. Both U-0126 and SB-203580 attenuated the acid-induced increase in COX-2 mRNA. Acid significantly increased COX-2 protein expression and promoter activity, and both of these effects were abolished by treatment with U-0126 and SB-203580. Acid exposure also stabilized COX-2 mRNA levels, an effect that was abolished by U-0126 but not by SB-203580. We conclude that acid increases COX-2 expression through activation of the MAPK pathways. Acid-induced activation of both ERK and p38 causes a significant increase in COX-2 promoter activity, and acid-activated ERK stabilizes COX-2 mRNA. These findings suggest potential mechanisms whereby acid reflux might promote carcinogenesis in Barrett's esophagus.

Acids↗
PubMed2003

Barrett's esophagus: chemoprevention.

The clinical applicability of the experimental data discussed previously remains questionable, and results of clinical studies on chemoprevention in Barrett's esophagus are needed. The utility of selectively targeting acid exposure, ODC, and COX-2 is not clear, and elucidation of that role will be facilitated by a better understanding of the contribution of these factors in the development of Barrett's cancers. The insights already gained into the basic mechanisms of acid exposure, ODC, and COX-2 in the pathogenesis of Barrett's esophagus and esophageal adenocarcinoma hold promise for the development of future therapies aimed at these molecular targets and their signaling pathways. In preclinical studies, the ability of COX-2 selective NSAIDs and DFMO to inhibit carcinogenesis is encouraging. Results of well-designed, prospective clinical studies, however, are still needed to establish the efficacy of potent acid suppression, COX-2 inhibitors, and DFMO in the prevention of this malignancy.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2003

Nighttime heartburn is an under-appreciated clinical problem that impacts sleep and daytime function: the results of a Gallup survey conducted on behalf of the American Gastroenterological Association.

OBJECTIVE: Although a large body of information exists about the prevalence of gastroesophageal reflux disease (GERD) in general, available data specifically addressing nocturnal reflux are limited. Because nocturnal acid reflux is reported to be associated with more severe injuries such as esophagitis and stricture, as well as adenocarcinoma of the esophagus, a better understanding of the prevalence and impact of nighttime heartburn as a sign of nocturnal acid reflux events can have significant potential management implications. The aims of this study were to determine the prevalence of nighttime heartburn and reflux-attributed supraesophageal symptoms among patients with GERD; and the impact of nighttime heartburn on sleep and several activities of daily living that could affect quality of life. METHODS: A nationwide telephone survey of 1000 adults experiencing heartburn at least once a week was conducted by the Gallup Organization on behalf of the American Gastroenterological Association. RESULTS: Altogether, 79% of respondents reported experiencing heartburn at night. Among those, 75% reported that symptoms affected their sleep, 63% believed that heartburn negatively affected their ability to sleep well, and 40% believed that nocturnal heartburn impaired their ability to function the following day. Of the 791 respondents with nighttime heartburn, 71% reported taking over-the-counter medicine for it, but only 29% of these rated this approach extremely effective. Forty-one percent reported trying prescription medicines, and 49% of these rated this approach extremely effective. CONCLUSIONS: Nighttime heartburn occurs in a large majority of adults with GERD, resulting in sleeping difficulties and impaired next-day function. The expected result from implemented therapy for heartburn is not achieved by a sizable percentage of patients.

Activities of Daily Living↗
PubMed2003

GERD 2003 -- a consensus on the way ahead.

Gastroesophageal reflux disease (GERD) has in recent times become an important public health issue owing to the considerable health care resources utilized in its management, its deleterious effect on quality of life and the increasing prevalence of a relatively rare complication of reflux disease - esophageal adenocarcinoma. We review here the major current challenges in the field of reflux disease and its complications, and provide some approaches that may be useful in management. The issues to be faced include the very limited comprehension of the reasons behind the increasing prevalence of the disease, difficulties in correlating symptoms with objective data of pathological gastroesophageal reflux and the relatively unsophisticated tools we are employing to investigate the underlying pathophysiology. It is certain that the lack of well-defined and characterized methodologies to compare the effects of therapy require the development of more effective questionnaire-type analytic tools. In regard to treatment, there is little doubt that the widely prescribed proton pump inhibitors have dose-equivalent efficacy and are the most highly effective agents capable of suppressing acid, controlling many of the symptoms of GERD and healing erosions. Nevertheless, many patients continue to experience symptoms on withdrawal or at night. Pharmacological agents that can effectively increase lower esophageal sphincter pressure or promote motility are as yet unavailable. Although the introduction of laparoscopic techniques has resulted in a modest revival in surgical intervention using a variety of 'wrap-type' operations, the indications are few and the procedure is associated with a significant morbidity and even mortality especially if the expertise of the surgeon is an issue. Endoscopic techniques of regulating reflux are at this time experimental and not applicable to the general population. Intestinal metaplasia in the lower esophagus is probably very common. Whether and how to, first, screen for, and then, perform surveillance in Barrett's esophagus remains highly problematic and contentious.

Barrett Esophagus↗
PubMed2002

Hallmarks of cancer progression in Barrett's oesophagus.

CONTEXT: Hanahan and Weinberg proposed in 200 that carcinogenesis involves DNA changes that enable cells to:provide their own growth signals, ignore growth-inhibitory signals, avoid apoptosis, replicate without limit, sustain angiogenesis, and invade and proliferate in unnatural locations. The metaplastic cells of Barrett's oesophagus are predisposed to develop these cancer hallmarks. STARTING POINT: The genetic changes that have been described in Barrett's oesophagus can be categorised according to the predominant cancer hallmark affected. For example, M Auvinen and colleagues recently observed abnormalities in the expression of vascular endothelial growth factors (VEGFs) in Barrett's oesophagus (J Clin Oncol 2002; 20: 2971-79). These abnormalities can be categorised as those that affect angiogenesis, a process that is essential for the development and progression of tumours. WHERE NEXT? The cancer hallmarks of Barrett's oesophagus provide a framework to categorise the genetic abnormalities described and to further understanding of the genetic events that underlie oesophageal carcinogenesis.

Aneuploidy↗
PubMedDate not supplied

Concepts in the prevention of adenocarcinoma of the distal esophagus and proximal stomach.

For decades, the incidence rates for squamous cell carcinoma of the esophagus and adenocarcinoma of the distal stomach have been declining while the rates for adenocarcinomas of the esophagus and gastric cardia have increased profoundly. Recent studies have shown that the gastroesophageal junction (GEJ) is regularly exposed to concentrated gastric acid and to a variety of nitrosating species, noxious agents that may contribute to carcinogenesis in this region. For adenocarcinomas that straddle the GEJ, it can be difficult to determine whether the tumor originated in the esophagus or in the gastric cardia. This classification problem hampers studies on the epidemiology and pathogenesis of GEJ tumors. Current concepts in the prevention of cancers of the distal esophagus and proximal stomach have emerged from advances in our understanding of the specific molecular events that occur during the evolution of these tumors. This report reviews those events and focuses on current concepts in the prevention of adenocarcinomas at the GEJ. The similarities and differences in risk factors, molecular pathogenesis, and in preventive strategies for adenocarcinomas of the esophagus and gastric cardia are highlighted.

Adenocarcinoma↗