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Enzyme kinetic parameters for aflatoxin B 1 metabolism have been reported for chicken, quail, turkey and duck, but an integrated in silico model has not been proposed. Both enzyme-catalyzed reactions and spontaneous reactions were modeled in the CellDesigner software and results were adjusted to Hill, Rational and Hoerl models. Results revealed that the higher amount of aflatoxin B 1 epoxide produced in a short lapse of time and a low production of epoxide conjugated to glutathione explains the severe genotoxic effect of aflatoxin B 1 in duck. Also, the higher amount of aflatoxicol produced is time-associated to aflatoxin B 1 resistance in chicken. Finally, the cytotoxic effects in quail and duck are caused by a large aflatoxin B 1 dialdehyde production in a short period of time., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

The Stefan problem regarding the formation of several liquid-solid interfaces produced by the oscillations of the ambient temperature around the melting point of a phase change material has been addressed by several authors. Numerical and semi-analytical methods have been used to find the thermal response of a phase change material under these type of boundary conditions. However, volume changes produced by the moving fronts and their effects on the thermal performance of phase change materials have not been addressed. In this work, volume changes are incorporated through an additional equation of motion for the thickness of the system. The thickness of the phase change material becomes a dynamic variable of motion by imposing total mass conservation. The modified equation of motion for each interface is obtained by coupling mass conservation with a local energy-mass balance at each front. The dynamics of liquid-solid interface configurations is analyzed in the transient and steady periodic regimes. Finite element and heat balance integral methods are used to verify the consistency of the solutions to the proposed model. The heat balance integral method is modified and adapted to find approximate solutions when two fronts collide, and the temperature profiles are not smooth. Volumetric corrections to the sensible and latent heat released (absorbed) are introduced during front formation, annihilation, and in the presence of two fronts. Finally, the thermal energy released by the interior surface is estimated through the proposed model and compared with the solutions obtained through models proposed by other authors.

Background: Many temporary stomas are never reversed leading to significantly worse quality of life. Recent evidence suggests a lower rate of reversal among minority patients. Our study aimed to elucidate disparities in national stoma closure rates by race, medical insurance status, and household income., Methods: Five years of data from the Nationwide Inpatient Sample (2008 to 2012) was used to identify the annual rates of stoma formation and annual rates of stoma closure. Stomas labeled as "permanent" or those created secondary to colorectal cancers were excluded. Temporary stoma closure rates were calculated, and differences were tested with the chi-square test. Separate analyses were performed by race/ethnicity, insurance status, and household income. Nationally representative estimates were calculated using discharge-level weights., Results: The 5-year average annual rate of temporary stoma creation was 76,551 per year (46% colostomies and 54% ileostomies). The annual rate of stoma reversal was 50,155 per year that equated to an annual reversal rate of 65.5%. Reversal rates were higher among white patients compared with black patients (67% vs 56%, P < .001) and among privately insured patients compared with uninsured patients (88% vs 63%, P < .001). Reversal rates increased as the household income increased from 61% in the lowest income quartile to 72% in the highest quartile (P < .001)., Conclusions: Stark disparities exist in national rates of stoma closure. Stoma closure is associated with race, insurance, and income status. This study highlights the lack of access to surgical health care among patients of minority race and low-income status., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background & Aims: Esophageal adenocarcinoma is believed to result from the progression of gastroesophageal reflux disease to erosive esophagitis and re-epithelialization of the esophagus with a columnar cell population termed Barrett's esophagus (BE). Men develop BE and esophageal adenocarcinoma more frequently than women, yet little is known about the mechanisms of this difference. We assessed whether sex steroid hormones were associated with BE in a male population., Methods: We analyzed data from the Barrett's Esophagus Early Detection Case Control Study, based at the Walter Reed National Military Medical Center. Blood samples were collected from 174 men with BE and 213 men without BE (controls, based on endoscopic analysis); 13 sex steroid hormones were measured by mass spectrometry and sex hormone binding globulin was measured by enzyme-linked immunosorbent assay. We also calculated free estradiol, free testosterone, and free dihydrotestosterone (DHT). We used multivariable logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for age, race, smoking status, alcohol consumption, body mass index, heartburn, regurgitation, and gastroesophageal symptom score (excluding heartburn and regurgitation)., Results: Levels of free testosterone and free DHT were associated positively with BE risk; patients in the highest quartile for these hormones were most likely to have BE (free testosterone: OR, 5.36; 95% CI, 2.21-13.03; P = .0002; free DHT: OR, 4.25; 95% CI, 1.87-9.66; P = .001). Level of estrone sulfate was associated inversely with BE risk (P for trend = .02). No other hormone was associated with BE risk. Relationships were not modified by age or BMI., Conclusions: In an analysis of men, levels of free testosterone and free DHT were significantly associated with BE., (Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.)

We recommend that uncomplicated GERD be diagnosed on the basis of typical symptoms without the use of diagnostic testing, including EGD. We recommend EGD for patients who have symptoms suggesting complicated GERD or alarm symptoms. We recommend that EGD not be routinely performed solely for the assessment of extraesophageal GERD symptoms. We recommend that endoscopic findings of reflux esophagitis be classified according to an accepted grading scale or described in detail. We suggest that repeat EGD be performed in patients with severe erosive esophagitis after at least an 8-week course of PPI therapy to exclude underlying BE or dysplasia. 44BB We recommend against obtaining tissue samples from endoscopically normal tissue to diagnose GERD or exclude BE in adults. We suggest that endoscopy be considered in patients with multiple risk factors for Barrett’s esophagus. We recommend that tissue samples be obtained to confirm endoscopically suspected Barrett’s esophagus. We suggest that endoscopic antireflux therapy be considered for selected patients with uncomplicated GERD after careful discussion with the patient regarding potential adverse effects, benefits, and other available therapeutic options.

Background: Barrett's esophagus (BE) is a metaplastic precursor lesion of esophageal adenocarcinoma (EA), the most rapidly increasing cancer in western societies. While the prevalence of BE is increasing, the vast majority of EA occurs in patients with undiagnosed BE. Thus, we sought to identify genes that are altered in BE compared to the normal mucosa of the esophagus, and which may be potential biomarkers for the development or diagnosis of BE., Design: We performed gene expression analysis using HG-U133A Affymetrix chips on fresh frozen tissue samples of Barrett's metaplasia and matched normal mucosa from squamous esophagus (NE) and gastric cardia (NC) in 40 BE patients., Results: Using a cut off of 2-fold and P<1.12E-06 (0.05 with Bonferroni correction), we identified 1324 differentially-expressed genes comparing BE vs NE and 649 differentially-expressed genes comparing BE vs NC. Except for individual genes such as the SOXs and PROM1 that were dysregulated only in BE vs NE, we found a subset of genes (n = 205) whose expression was significantly altered in both BE vs NE and BE vs NC. These genes were overrepresented in different pathways, including TGF-β and Notch., Conclusion: Our findings provide additional data on the global transcriptome in BE tissues compared to matched NE and NC tissues which should promote further understanding of the functions and regulatory mechanisms of genes involved in BE development, as well as insight into novel genes that may be useful as potential biomarkers for the diagnosis of BE in the future.

Upper gastrointestinal bleeding (UGIB) is an important medical problem for patients and the medical system. The causes of UGIB are varied and their accurate identification guides appropriate management. The major cause of UGIB is peptic ulcer disease, for which Helicobacter pylori and nonsteroidal antiinflammatory drug use are major risk factors. Lesser causes include Dieulafoy lesion, gastric antral vascular ectasia, hemobilia, aortoenteric fistulas, and upper gastrointestinal tumors. Awareness of causes and management of UGIB should allow physicians to treat their patients more effectively., (Published by Elsevier Inc.)

Introduction: Irritable bowel syndrome is a common disorder that is associated with a significant impact on both affected individuals and society. While the pathophysiology of irritable bowel syndrome remains unknown, knowledge regarding the normal and abnormal functions of the gut and its complex interaction with the body's nervous systems continues to shed light on the multifactorial origins of irritable bowel syndrome symptoms. This article provides an overview of the current knowledge of the therapeutic approaches to irritable bowel syndrome., Areas Covered: A search of the online bibliographic databases MEDLINE and EMBASE was performed in order to identify all relevant articles published between 1980 and 2010. The search was enhanced with the use of a medical librarian. Bibliographies from potentially relevant articles were manually searched., Expert Opinion: The therapeutic options for irritable bowel syndrome are rapidly evolving beyond traditional symptom-based therapies, such as fiber, antispasmodics, antidiarrheals and laxatives, and are moving toward agents with organ-specific receptor selectivity directed, in many cases, at specific gastrointestinal functions.

Background & Aims: Patients with esophageal high-grade dysplasia or mucosal esophageal cancer can be successfully treated by endoscopy. We performed a systematic review of the literature to determine whether endoscopic ultrasound (EUS) correctly predicts the T-stage of early esophageal cancers, compared with pathology specimens obtained by using endoscopic mucosal resection (EMR) or surgery., Methods: Standard systematic review methods were used to perform reference searches, determine eligibility, abstract data, and analyze data. When possible, individual patient-level data were abstracted, in addition to publication-level aggregate data., Results: Twelve studies had sufficient information to abstract and review for quality; 8 had individual patient-level data (n = 132). Compared with surgical or EMR pathology staging, EUS had T-stage concordance of 65%, including all studies (n = 12), but only 56% concordance when limited to individual patient-level data. Factors such as initial biopsy pathology (high-grade dysplasia vs early-stage cancer) did not appear to affect the concordance of staging between EUS and EMR/surgical staging., Conclusions: EUS is not sufficiently accurate in determining the T-stage of high-grade dysplasias or superficial adenocarcinomas; other means of staging, such as EMR, should be used., (Copyright © 2010 AGA Institute. Published by Elsevier Inc. All rights reserved.)

The practice of colonic cleansing to promote general health and well-being continues to generate interest among the lay population. These practices are widely touted as adjuncts to improve vitality and as therapeutic modalities to minimize the symptoms, or prevent the actual development, of a variety of chronic disease states. The data supporting colonic cleansing and body "detoxification" have not been studied well in a systematic manner. This report describes a systematic review of the published literature of both the traditional and complementary and alternative medicine arenas that was performed in an attempt to qualify and quantify the value of colonic cleansing. The investigators concluded that there are no methodologically rigorous controlled trials of colonic cleansing to support the practice for general health promotion. Conversely, there are multiple case reports and case series that describe the adverse effects of colonic cleansing. The practice of colonic cleansing to improve or promote general health is not supported in the published literature and cannot be recommended at this time.

Context: The role of EUS to evaluate subtle radiographic abnormalities of the pancreas is not well defined., Objective: To assess the yield of EUS+/-FNA for focal or diffuse pancreatic enlargement/fullness seen on abdominal CT scan in the absence of discrete mass lesions., Design: Retrospective database review., Setting: Tertiary referral center., Patients and Interventions: Six hundred and 91 pancreatic EUS exams were reviewed. Sixty-nine met inclusion criteria of having been performed for focal enlargement or fullness of the pancreas. Known chronic pancreatitis, pancreatic calcifications, acute pancreatitis, discrete mass on imaging, pancreatic duct dilation (greater than 4 mm) and obstructive jaundice were excluded., Main Outcome Measurement: Rate of malignancy found by EUS+/-FNA., Results: FNA was performed in 19/69 (27.5%) with 4 new diagnoses of pancreatic adenocarcinoma, one metastatic renal cell carcinoma, one metastatic colon cancer, one chronic pancreatitis and 12 benign results. Eight patients had discrete mass lesions on EUS; two were cystic. All malignant diagnoses had a discrete solid mass on EUS., Conclusions: Pancreatic enlargement/fullness is often a benign finding related to anatomic variation, but was related to malignancy in 8.7% of our patients (6/69). EUS should be strongly considered as the next step in the evaluation of patients with focal enlargement of the pancreas when clinical suspicion of malignancy exists.

Background: Many men older than 50 years have bioavailable testosterone levels below the reference range for young adult men. The impact of the decreased androgen levels on cognition and health perception has received little attention., Methods: Sixty-seven men (mean age 76 +/- 4 years, range 65-87) with bioavailable testosterone levels below 128 ng/dl (lower limit for adult normal range) were randomized to receive transdermal testosterone (2-2.5 mg patches/d) or placebo patches for 1 year. All men received 500 mg supplemental calcium and 400 IU vitamin D. Outcome measures included sex hormones [testosterone, bioavailable testosterone, sex hormone binding globulin (SHBG), estradiol, and estrone], cognitive tests (Digit Symbol, Digit Span, Trailmaking A and B), health perception (Medical Outcome Survey Short-form 36 or SF-36), lower extremity muscle strength and power, and calcium intake., Results: Twenty-three men (34%) withdrew from the study; 44 men completed the trial. Bioavailable testosterone levels increased from 93 +/- 34 (SD) to 162 +/- 100 ng/dl (p <.002) at 12 months in the testosterone group (n = 24) while no change occurred in the control group (n = 20). While there was no change in estradiol levels in either group, estrone levels increased in the testosterone group (28 +/- 7 to 32 +/- 9 pg/dl, p =.017). Scores on the Digit Symbol test improved in both the testosterone and placebo groups. Scores on Trailmaking B improved in men treated with testosterone (p <.005), although the changes were not statistically different from the changes seen in the placebo group. Twelve-month scores on Trailmaking B for the entire group were correlated with 12-month testosterone levels (p =.016). Scores for health perception measured by SF-36 did not change significantly, though scores of mental and general health declined in both groups during the 12-month intervention. Twelve-month bioavailable testosterone scores were directly correlated with scores for physical role (p =.022), vitality (p =.036), and the physical composite score (p =.010)., Conclusions: Transdermal testosterone treatment in men with low bioavailable testosterone levels does not impair and may improve cognitive function. Treatment did not improve health perception but this may have been due to the side effects of skin irritation suggested by similar reactions in both the testosterone and placebo groups.