Neighbourhood inequities in the availability of retailers selling tobacco products: a systematic review.

OBJECTIVE: To examine inequities in tobacco retailer availability by neighbourhood-level socioeconomic, racial/ethnic and same-sex couple composition. DATA SOURCES: We conducted a 10 November 2022 search of PubMed, PsycINFO, Global Health, LILACS, Embase, ABI/Inform, CINAHL, Business Source Complete, Web of Science and Scopus. STUDY SELECTION: We included records from Organisation for Economic Co-operation and Development member countries that tested associations of area-level measures of tobacco retailer availability and neighbourhood-level sociodemographic characteristics. Two coders reviewed the full text of eligible records (n=58), including 41 records and 205 effect sizes for synthesis. DATA EXTRACTION: We used dual independent screening of titles, abstracts and full texts. One author abstracted and a second author confirmed the study design, location, unit of analysis, sample size, retailer data source, availability measure, statistical approach, sociodemographic characteristic and unadjusted effect sizes. DATA SYNTHESIS: Of the 124 effect sizes related to socioeconomic inequities (60.5% of all effect sizes), 101 (81.5%) indicated evidence of inequities. Of 205 effect sizes, 69 (33.7%) tested associations between retailer availability and neighbourhood composition of racially and ethnically minoritised people, and 57/69 (82.6%) documented inequities. Tobacco availability was greater in neighbourhoods with more Black, Hispanic/Latine and Asian residents (82.8%, 90.3% and 40.0% of effect sizes, respectively). Two effect sizes found greater availability with more same-sex households. CONCLUSIONS: There are stark inequities in tobacco retailer availability. Moving beyond documenting inequities to partnering with communities to design, implement, and evaluate interventions that reduce and eliminate inequities in retail availability is needed to promote an equitable retail environment. PROSPERO REGISTRATION NUMBER: CRD42019124984.

A Scoping Review of Trends in the Size of Lesbian, Gay, and Bisexual Tobacco Use Disparities, 1996-2020, United States and Canada.

Purpose: Tobacco use is a major health disparity for lesbian, gay, bisexual, and transgender (LGBT) populations compared with heterosexual/cisgender populations. In this scoping review, we aimed to determine if LGBT tobacco use disparities are improving or worsening over time and if trends in disparities differed across subgroups. Methods: We included articles that longitudinally explored youth and adult LGB tobacco use in the United States and Canada after searching four databases and capturing records through July 2022. Two reviewers independently screened the title/abstract and full text of 2326 and 45 articles, respectively. Eleven articles from 18 larger assessments met inclusion criteria, spanning data collection from 1996 to 2020. Results: All studies consistently demonstrated tobacco disparities for LGB populations. No articles examined longitudinal transgender tobacco disparities. Most studies focused on smoking combustible cigarettes. Disparities in heavy or daily use for all LGB youth subgroups compared with heterosexual samples appear to be shrinking longitudinally. Results for early-onset, current, and lifetime smoking were less consistent. Adult evidence was relatively sparse; however, after 2010, studies show diminishing disparities over time, except for current smoking by bisexual women. Conclusions: Large tobacco use disparities persist for LGB populations, although the size of disparities may be decreasing for some groups. Initiatives for lesbian and bisexual women and girls should be prioritized, in addition to interventions addressing LGB smoking broadly. Surveillance instruments should uniformly and consistently assess LGBT identities and tobacco use behaviors.

Microplastics in water: Occurrence, fate and removal.

A global study on tap water samples has found that up to 83% of these contained microplastic fibres. These findings raise concerns about their potential health risks. Ingested microplastic particles have already been associated with harmful effects in animals, which raise concerns about similar outcomes in humans. Microplastics are ubiquitous in the environment, commonly found disposed in landfills and waste sites. Within indoor environments, the common sources are synthetic textiles, plastic bottles, and packaging. From the various point sources, they are globally distributed through air and water and can enter humans through various pathways. The finding of microplastics in fresh snow in the Antarctic highlights just how widely they are dispersed. The behaviour and health risks from microplastic particles are strongly influenced by their physicochemical properties, which is why their surfaces are important. Surface interactions are also important in pollutant transport via adsorption onto the microplastic particles. Our review covers the latest findings in microplastics research including the latest statistics in their abundance, their occurrence and fate in the environment, the methods of reducing microplastics exposure and their removal. We conclude by proposing future research directions into more effective remediation methods including new technologies and sustainable green remediation methods that need to be explored to achieve success in microplastics removal from waters at large scale.

Hypoxia-inducible factor-1α mediates reflux-induced epithelial-mesenchymal plasticity in Barrett's oesophagus patients.

INTRODUCTION: Epithelial-mesenchymal plasticity (EMP), the process through which epithelial cells acquire mesenchymal features, is needed for wound repair but also might contribute to cancer initiation. Earlier, in vitro studies showed that Barrett's cells exposed to acidic bile salt solutions (ABS) develop EMP. Now, we have (1) induced reflux oesophagitis in Barrett's oesophagus (BO) patients by stopping proton pump inhibitors (PPIs), (2) assessed their biopsies for EMP and (3) explored molecular pathways underlying reflux-induced EMP in BO cells and spheroids. METHODS: 15 BO patients had endoscopy with biopsies of Barrett's metaplasia while on PPIs, and 1 and 2 weeks after stopping PPIs; RNA-seq data were assessed for enrichments in hypoxia-inducible factors (HIFs), angiogenesis and EMP pathways. In BO biopsies, cell lines and spheroids, EMP features (motility) and markers (vascular endothelial growth factor (VEGF), ZEB1, miR-200a&b) were evaluated by morphology, migration assays, immunostaining and qPCR; HIF-1α was knocked down with siRNA or shRNA. RESULTS: At 1 and/or 2 weeks off PPIs, BO biopsies exhibited EMP features and markers, with significant enrichment for HIF-1α, angiogenesis and EMP pathways. In BO cells, ABS induced HIF-1α activation, which decreased miR-200a&b while increasing VEGF, ZEB1 and motility; HIF-1α knockdown blocked these effects. After ABS treatment, BO spheroids exhibited migratory protrusions showing nuclear HIF-1α, increased VEGF and decreased miR-200a&b. CONCLUSIONS: In BO patients, reflux oesophagitis induces EMP changes associated with increased HIF-1α signalling in Barrett's metaplasia. In Barrett's cells, ABS trigger EMP via HIF-1α signalling. Thus, HIF-1α appears to play a key role in mediating reflux-induced EMP that might contribute to cancer in BO. TRIAL REGISTRATION NUMBER: NCT02579460.

Behavioral Therapy for Functional Heartburn: Recommendation Statements.

BACKGROUND & AIMS: Brain-gut behavior therapies (BGBT) are increasingly recognized as effective therapeutic interventions for functional heartburn. However, recommendations regarding candidacy for treatment, initial treatment selection, and navigating treatment non-response have not been established for functional heartburn specifically. The aim of this study was to establish expert-based recommendations for behavioral treatment in patients with functional heartburn. METHODS: The validated RAND/University of California, Los Angeles Appropriateness Method was applied to develop recommendations. A 15-member panel composed of 10 gastrointestinal psychologists and 5 esophageal specialists ranked the appropriateness of a series of statements on a 9-point interval scale over 2 ranking periods. Statements were within the following domains: pre-therapy evaluation, candidacy criteria for BGBT, selection of initial BGBT, role of additional therapy for initial non-response to BGBT, and role of pharmacologic neuromodulation. The primary outcome was appropriateness of each intervention based on the recommendation statements. RESULTS: Recommendations for psychosocial assessment (eg, hypervigilance, symptom-specific anxiety, health-related quality of life), candidacy criteria (eg, motivated for BGBT, acknowledges the role of stress in symptoms), and treatment were established. Gut-directed hypnotherapy or cognitive behavioral therapy were considered appropriate BGBT for functional heartburn. Neuromodulation and/or additional BGBT were considered appropriate in the context of non-response. CONCLUSIONS: Gut-directed hypnotherapy and/or cognitive behavioral therapy are recommended as appropriate behavioral interventions for heartburn symptoms, depending on clinical indication, specific gut-brain targets, and preferred treatment modality (pharmacologic vs non-pharmacologic). Pre-therapy evaluation of psychosocial processes and candidacy for BGBT are important to determine eligibility for referral to psychogastroenterology services.

Gender Identity and Mental Health Symptom Severity Among Adolescents Admitted to an Inpatient Psychiatric Hospital.

Transgender youth are at an increased risk of suicide, substance use, experiencing violent assaults, and reporting major depressive episodes and greater psychological distress compared to their cisgender counterparts. This study examined mental health symptom severity in adolescents admitted to an inpatient psychiatric hospital who wished they were of a different gender compared to those who did not. A group of 180 adolescents admitted to an inpatient psychiatric hospital completed assessments to measure mental health symptom severity at admission. Gender diverse (n = 90) and cisgender (n = 90) groups were established. Analyses of variance (ANOVA) were used to examine between group (gender diverse vs. cisgender) difference on depression, anxiety, suicide risk, nighttime sleep quality, and emotion regulation problems. Results revealed significant differences in emotion regulation difficulties at admission, specifically in nonacceptance and awareness. There were no significant differences on measures of depression, anxiety, suicide risk, and nighttime sleep quality at admission. This study is one of the first to measure mental health symptom severity in gender diverse adolescents while admitted to an inpatient psychiatric setting. Adolescents in the gender diverse group had significantly higher level of difficulty with emotion regulation, which may indicate an increased risk of developing psychiatric symptoms such as depression and anxiety. This paper demonstrates the importance of using targeted interventions to address difficulties with emotion regulation in at-risk adolescents.

Application and impact of Lasso regression in gastroenterology: A systematic review.

Least absolute shrinkage and selection operator (Lasso) regression is a statistical technique that can be used to study the effects of clinical variables in outcome prediction. In this study, we aimed at systematically reviewing the application of Lasso regression in gastroenterology for developing predictive models and providing a method of performing Lasso regression. A comprehensive search strategy was conducted in PubMed, Embase and Cochrane CENTRAL databases (Keywords: lasso regression; gastrointestinal tract/diseases) following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were screened for eligibility based on pre-defined selection criteria and the data was extracted using a standardized form. Total 16 studies were included, comprising a diverse range of gastroenterological disease-related outcomes. Sample sizes ranged from 134 to 8861 subjects. Eleven studies reported liver disease-related prediction models, while five focused on non-hepatic etiology models. Lasso regression was applied for variable selection, risk prediction and model development, with various validation methods and performance metrics used. Model performance metrics included Area Under the Receiver Operating Characteristics (AUROC), C-index and calibration plots. In gastroenterology, Lasso regression has been used in various diseases such as inflammatory bowel disease, liver disease and esophageal cancer. It is valuable for complex scenarios with many predictors. However, its effectiveness depends on high-quality and complete data. While it identifies important variables, it doesn't provide causal interpretations. Therefore, cautious interpretation is necessary considering the study design and data quality.

Baseline Features and Reasons for Nonparticipation in the Colonoscopy Versus Fecal Immunochemical Test in Reducing Mortality From Colorectal Cancer (CONFIRM) Study, a Colorectal Cancer Screening Trial.

Importance: The Colonoscopy Versus Fecal Immunochemical Test in Reducing Mortality From Colorectal Cancer (CONFIRM) randomized clinical trial sought to recruit 50 000 adults into a study comparing colorectal cancer (CRC) mortality outcomes after randomization to either an annual fecal immunochemical test (FIT) or colonoscopy. Objective: To (1) describe study participant characteristics and (2) examine who declined participation because of a preference for colonoscopy or stool testing (ie, fecal occult blood test [FOBT]/FIT) and assess that preference's association with geographic and temporal factors. Design, Setting, and Participants: This cross-sectional study within CONFIRM, which completed enrollment through 46 Department of Veterans Affairs medical centers between May 22, 2012, and December 1, 2017, with follow-up planned through 2028, comprised veterans aged 50 to 75 years with an average CRC risk and due for screening. Data were analyzed between March 7 and December 5, 2022. Exposure: Case report forms were used to capture enrolled participant data and reasons for declining participation among otherwise eligible individuals. Main Outcomes and Measures: Descriptive statistics were used to characterize the cohort overall and by intervention. Among individuals declining participation, logistic regression was used to compare preference for FOBT/FIT or colonoscopy by recruitment region and year. Results: A total of 50 126 participants were recruited (mean [SD] age, 59.1 [6.9] years; 46 618 [93.0%] male and 3508 [7.0%] female). The cohort was racially and ethnically diverse, with 748 (1.5%) identifying as Asian, 12 021 (24.0%) as Black, 415 (0.8%) as Native American or Alaska Native, 34 629 (69.1%) as White, and 1877 (3.7%) as other race, including multiracial; and 5734 (11.4%) as having Hispanic ethnicity. Of the 11 109 eligible individuals who declined participation (18.0%), 4824 (43.4%) declined due to a stated preference for a specific screening test, with FOBT/FIT being the most preferred method (2820 [58.5%]) vs colonoscopy (1958 [40.6%]; P < .001) or other screening tests (46 [1.0%] P < .001). Preference for FOBT/FIT was strongest in the West (963 of 1472 [65.4%]) and modest elsewhere, ranging from 199 of 371 (53.6%) in the Northeast to 884 of 1543 (57.3%) in the Midwest (P = .001). Adjusting for region, the preference for FOBT/FIT increased by 19% per recruitment year (odds ratio, 1.19; 95% CI, 1.14-1.25). Conclusions and Relevance: In this cross-sectional analysis of veterans choosing nonenrollment in the CONFIRM study, those who declined participation more often preferred FOBT or FIT over colonoscopy. This preference increased over time and was strongest in the western US and may provide insight into trends in CRC screening preferences.

The Use of Infrared Spectroscopy for the Quantification of Bioactive Compounds in Food: A Review.

Infrared spectroscopy (wavelengths ranging from 750-25,000 nm) offers a rapid means of assessing the chemical composition of a wide range of sample types, both for qualitative and quantitative analyses. Its use in the food industry has increased significantly over the past five decades and it is now an accepted analytical technique for the routine analysis of certain analytes. Furthermore, it is commonly used for routine screening and quality control purposes in numerous industry settings, albeit not typically for the analysis of bioactive compounds. Using the Scopus database, a systematic search of literature of the five years between 2016 and 2020 identified 45 studies using near-infrared and 17 studies using mid-infrared spectroscopy for the quantification of bioactive compounds in food products. The most common bioactive compounds assessed were polyphenols, anthocyanins, carotenoids and ascorbic acid. Numerous factors affect the accuracy of the developed model, including the analyte class and concentration, matrix type, instrument geometry, wavelength selection and spectral processing/pre-processing methods. Additionally, only a few studies were validated on independently sourced samples. Nevertheless, the results demonstrate some promise of infrared spectroscopy for the rapid estimation of a wide range of bioactive compounds in food matrices.

Fruit Sizing in Orchard: A Review from Caliper to Machine Vision with Deep Learning.

Forward estimates of harvest load require information on fruit size as well as number. The task of sizing fruit and vegetables has been automated in the packhouse, progressing from mechanical methods to machine vision over the last three decades. This shift is now occurring for size assessment of fruit on trees, i.e., in the orchard. This review focuses on: (i) allometric relationships between fruit weight and lineal dimensions; (ii) measurement of fruit lineal dimensions with traditional tools; (iii) measurement of fruit lineal dimensions with machine vision, with attention to the issues of depth measurement and recognition of occluded fruit; (iv) sampling strategies; and (v) forward prediction of fruit size (at harvest). Commercially available capability for in-orchard fruit sizing is summarized, and further developments of in-orchard fruit sizing by machine vision are anticipated.

Reduced fire severity offers near-term buffer to climate-driven declines in conifer resilience across the western United States.

Increasing fire severity and warmer, drier postfire conditions are making forests in the western United States (West) vulnerable to ecological transformation. Yet, the relative importance of and interactions between these drivers of forest change remain unresolved, particularly over upcoming decades. Here, we assess how the interactive impacts of changing climate and wildfire activity influenced conifer regeneration after 334 wildfires, using a dataset of postfire conifer regeneration from 10,230 field plots. Our findings highlight declining regeneration capacity across the West over the past four decades for the eight dominant conifer species studied. Postfire regeneration is sensitive to high-severity fire, which limits seed availability, and postfire climate, which influences seedling establishment. In the near-term, projected differences in recruitment probability between low- and high-severity fire scenarios were larger than projected climate change impacts for most species, suggesting that reductions in fire severity, and resultant impacts on seed availability, could partially offset expected climate-driven declines in postfire regeneration. Across 40 to 42% of the study area, we project postfire conifer regeneration to be likely following low-severity but not high-severity fire under future climate scenarios (2031 to 2050). However, increasingly warm, dry climate conditions are projected to eventually outweigh the influence of fire severity and seed availability. The percent of the study area considered unlikely to experience conifer regeneration, regardless of fire severity, increased from 5% in 1981 to 2000 to 26 to 31% by mid-century, highlighting a limited time window over which management actions that reduce fire severity may effectively support postfire conifer regeneration.

A systematic review of the effectiveness of patient education through patient portals.

Objective: The objective of this study was to systematically review all literature studying the effect of patient education on patient engagement through patient portals. Introduction: Patient portals provide patients access to health records, lab results, medication refills, educational materials, secure messaging, appointment scheduling, and telehealth visits, allowing patients to take a more active role in their health care decisions and management. A debate remains around whether these additional aids actually improve patient engagement and increase their ability to manage their own health conditions. This systematic review looks specifically at the effect of educational materials included in patient portals. Materials and Methods: In accordance with PRISMA guidelines, the literature search was mapped across 5 databases (PubMed, CINAHL, Scopus, PsychINFO, Embase), and implemented on June 2, 2020. Results: Fifty-two studies were included in the review. Forty-six (88.5%) reported rates of patient utilization of educational resources in the patient portal. Thirty (57.9%) shared patients' perceptions of the usefulness of the education materials. Twenty-one (40.4%) reported changes in health outcomes following educational interventions through the patient portal. This review found that efforts are indeed being made to raise awareness of educational resources in patient portals, that patients are increasingly utilizing these resources, that patients are finding them useful, and that they are improving health outcomes. Conclusion: It seems that patient portals are becoming a powerful tool for patient education and engagement, and show promise as a means of achieving the quadruple aim of healthcare. Moving forward, research should establish more uniform methods of measurement in order to strengthen the literature surrounding the effectiveness of patient education through patient portals.

New-Onset Psychosis in the Context of COVID-19 Infection: An Illustrative Case and Literature Review.

BACKGROUND: Infection with COVID-19 virus can result in a wide array of neuropsychiatric symptoms, such as anxiety, depression, psychosis, and delirium. Complications can occur even in the absence of a severe respiratory illness. OBJECTIVE: To recognize patterns in the presentation and treatment of patients with psychosis in the context of COVID-19 infection to help inform clinicians who directly care for these patients. METHODS: In this case report and literature review, the authors first present a case of a 70-year-old female who developed new-onset psychosis in the context of mild infection with COVID-19. The authors then review the literature to present case reports that describe patients similar to the female patient presented. RESULTS: The patient presented in the case report showed improved psychotic symptoms after 3 days of receiving a very low dose of risperidone. Of the case reports reviewed, more than half of the patients presented showed improvement of psychotic symptoms on low or very low doses of antipsychotics. CONCLUSIONS: This review shows the necessity of additional research on psychosis due to COVID-19 in order to better understand the course of illnesses and the most effective treatment.

COVID-19 Vaccines and the Virus: Impact on Drug Metabolism and Pharmacokinetics.

This article reports on an American Society of Pharmacology and Therapeutics, Division of Drug Metabolism and Disposition symposium held at Experimental Biology on April 2, 2022, in Philadelphia. As of July 2022, over 500 million people have been infected with SARS-CoV-2 (the virus causing COVID-19) and over 12 billion vaccine doses have been administered. Clinically significant interactions between viral infections and hepatic drug metabolism were first recognized over 40 years ago during a cluster of pediatric theophylline toxicity cases attributed to reduced hepatic drug metabolism amid an influenza B outbreak. Today, a substantive body of research supports that the activated innate immune response generally decreases hepatic cytochrome P450 activity. The interactions extend to drug transporters and other organs and have the potential to impact drug absorption, distribution, metabolism, and excretion (ADME). Based on this knowledge, altered ADME is predicted with SARS-CoV-2 infection or vaccination. The report begins with a clinical case exploring the possibility of SARS-CoV-2 vaccination increasing clozapine levels. This is followed by discussions of how SARS-CoV-2 infection or vaccines alter the metabolism and disposition of complex drugs, such as nanoparticles and biologics and small molecule therapies. The review concludes with a discussion of the effects of viral infections on placental amino acid transport and their potential to impact fetal development. The session improved our understanding of the impact of emerging viral infections and vaccine technologies on drug metabolism and disposition, which will help mitigate drug toxicity and improve drug and vaccine safety and effectiveness. SIGNIFICANCE STATEMENT: Altered pharmacokinetics of small molecule and complex molecule drugs and fetal brain distribution of amino acids following SARS-CoV-2 infection or immunization are possible. The proposed mechanisms involve decreased liver cytochrome P450 metabolism of small molecules, enhanced innate immune system metabolism of complex molecules, and altered placental and fetal blood-brain barrier amino acid transport, respectively. Future research is needed to understand the effects of these interactions on adverse drug responses, drug and vaccine safety, and effectiveness and fetal neurodevelopment.

Bioassay Guided Fractionation Protocol for Determining Novel Active Compounds in Selected Australian Flora.

A large variety of unique and distinct flora of Australia have developed exceptional survival methods and phytochemicals and hence may provide a significant avenue for new drug discovery. This study proposes a bioassay guided fractionation protocol that maybe robust and efficient in screening plants with potential bioactive properties and isolating lead novel compounds. Hence, five native Australian plants were selected for this screening process, namely Pittosporum angustifolium (Gumbi gumbi), Terminalia ferdinandiana (Kakadu plum, seeds (KPS), and flesh (KPF)), Cupaniopsis anacardioides (Tuckeroo, seeds (TKS) and flesh (TKF)), Podocarpus elatus (Illawarra plum, seeds (IPS) and flesh (IPF)) and Pleiogynium timoriense (Burdekin plum, seeds (BPS) and flesh (BPF)). The methanolic extracts of the plants samples were analysed for Total phenolic content (TPC) and antioxidant capacity measure by FRAP. The highest values were found in the KPF which were 12,442 ± 1355 mg GAE/ 100 g TPC and 16,670 ± 2275 mg TXE/100 g antioxidant capacity. Extracts of GGL was deemed to be most potent with complete cell inhibition in HeLa and HT29, and about 95% inhibition in HuH7 cells. Comparative activity was also seen for KPS extract, where more than 80% cell inhibition occurred in all tested cell lines. Dose-dependent studies showed higher SI values (0.72-1.02) in KPS extracts than GGL (0.5-0.73). Microbial assays of the crude extracts were also performed against five bacterial strains commonly associated with causing food poisoning diseases were selected (Gram positive-Staphylococcus aureus and Gram negative-Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa bacteria). KPF extracts were effective in suppressing microbial growth of all tested bacterial strains except for P. aeruginosa, while TKS and TKF were only slightly effective against S. aureus. Due to the potential of the GGL crude extract to completely inhibit the cells compared to KPS, it was further fractionated and tested against the cell lines. HPLC phenolic profiling of the crude extracts were performed, and numerous peak overlaps were evident in the fruit extracts. The KPF extracts demonstrated the strongest peaks which was coherent with the fact that it had the highest TPC and antioxidant capacity values. A high occurrence of t-ferulic acid in the GGL extracts was found which may explain the cytotoxic activity of GGL extracts. Peaks in KPS and KPF extracts were tentatively identified as gallic acid, protocatechuic acid, 4-hydroxybenzoic acid and syringic acid and possibly ellagic acid. HPLC time-based fractionation of the GGL extract (F1-F5) was performed and Dose dependent cytotoxic effects were determined. It was construed that F1, having the highest SI value for HeLa, HT29 and HuH7 (1.60, 1.41 and 1.67, respectively) would be promising for further fractionation and isolation process.

An Endoscopic and Histologic Study on Healing of Radiofrequency Ablation Wounds in Patients With Barrett's Esophagus.

INTRODUCTION: Radiofrequency ablation (RFA) of Barrett's esophagus (BE) inflicts a wound spanning 3 epithelial types (stratified squamous, Barrett's metaplasia, gastric epithelium), yet the esophageal injury heals almost completely with squamous epithelium. Knowledge of how this unique wound heals might elucidate mechanisms underlying esophageal metaplasia. We aimed to prospectively and systematically characterize the early endoscopic and histologic features of RFA wound healing. METHODS: Patients with nondysplastic BE had endoscopy with systematic esophageal photographic mapping, biopsy, and volumetric laser endomicroscopy performed before and at 1, 2, and 4 weeks after RFA. RESULTS: Seven patients (6 men; mean age 56.1 ± 10.9 years) completed this study. Squamous re-epithelialization of RFA wounds did not only progress exclusively through squamous cells extending from the proximal wound edge but also progressed through islands of squamous epithelium sprouting throughout the ablated segment. Volumetric laser endomicroscopy revealed significant post-RFA increases in subepithelial glandular structures associated with the squamous islands. In 2 patients, biopsies of such islands revealed newly forming squamous epithelium contiguous with immature-appearing squamous cells arising from esophageal submucosal gland ducts. Subsquamous intestinal metaplasia (SSIM) was found in biopsies at 2 and/or 4 weeks after RFA in 6 of 7 patients. DISCUSSION: RFA wounds in BE are re-epithelialized, not just by squamous cells from the proximal wound margin but by scattered squamous islands in which esophageal submucosal gland duct cells seem to redifferentiate into the squamous progenitors that fuel squamous re-epithelialization. SSIM can be found in most patients during the healing process. We speculate that this SSIM might underlie Barrett's recurrences after apparently successful eradication.