The endoscopic management of oesophageal strictures.

An oesophageal stricture refers to a narrowing of the oesophageal lumen, which may be benign or malignant. The cardinal feature is dysphagia, and this may result from intrinsic oesophageal disease or extrinsic compression. Oesophageal strictures can be further classified as simple or complex depending on stricture length, location, diameter, and underlying aetiology. Many endoscopic options are now available for treating oesophageal strictures including dilatation, injectional therapy, stenting, stricturotomy, and ablation. Self-expanding metal stents have revolutionised the palliation of malignant dysphagia, but oesophageal dilatation with balloon or bougienage remains first-line therapy for most benign strictures. The increase in endoscopic and surgical interventions on the oesophagus has seen more benign refractory oesophageal strictures that are difficult to treat, and often require advanced endoscopic techniques. In this review, we provide a practical overview on the evidence-based management of both benign and malignant oesophageal strictures, including a practical algorithm for managing benign refractory strictures.

Risk of metastasis among patients diagnosed with high-risk T1 esophageal adenocarcinoma who underwent endoscopic follow-up.

Esophagectomy and lymphadenectomy have been the standard of care for patients at high risk (HR) of lymph node metastasis following a diagnosis of early esophageal adenocarcinoma (OAC) after endoscopic resection (ER). However, recent cohorts suggest lymph node metastasis risk is lower than initially estimated, suggesting organ preservation with close endoscopic follow-up is a viable option. We report on the 3- and 5-year risk of lymph node/distant metastasis among patients diagnosed with early HR-T1 OAC undergoing endoscopic follow-up. Patients diagnosed with HR-T1a or T1b OAC following ER at a tertiary referral center were identified and retrospectively analyzed from clinical records between 2010 and 2021. Patients were included if they underwent endoscopic follow-up after resection and were divided into HR-T1a, low risk (LR)-T1b and HR-T1b cohorts. After ER, 47 patients underwent endoscopic follow-up for early HR OAC. In total, 39 patients had an R0 resection with a combined 3- and 5-year risk of LN/distant metastasis of 6.9% [95% confidence interval (CI): 1.8-25] and 10.9% (95% CI, 3.6-30.2%), respectively. There was no significant difference when stratifying by histopathological subtype (P = 0.64). Among those without persistent luminal disease on follow-up, the 5-year risk was 4.1% (95% CI, 0.6-26.1). Two patients died secondary to OAC with an all-cause 5-year survival of 57.5% (95% CI, 39.5-71.9). The overall risk of LN/distant metastasis for early HR T1 OAC was lower than historically reported. Endoscopic surveillance can be a reasonable approach in highly selected patients with an R0 resection and complete luminal eradication, but clear, evidence-based surveillance guidelines are needed.

Peroral endoscopic myotomy for the management of symptomatic cricopharyngeal bar (C-POEM): a case series and video demonstration.

Background: A cricopharyngeal bar refers to a radiological description of a prominent cricopharyngeal muscle. While these may be incidental, they can lead to significant oropharyngeal dysphagia due to incoordination of the upper esophageal sphincter and true luminal narrowing. Various treatments have been used for the management of cricopharyngeal bar, including botulinum toxin injection, dilation, and surgical myotomy. Cricopharyngeal peroral endoscopic myotomy (C-POEM) is a novel procedure that uses the principles of "third-space" endoscopy to treat symptomatic cricopharyngeal bar. Methods: We report a retrospective case series of 5 patients referred with oropharyngeal dysphagia to 2 UK tertiary referral centers between 2022 and 2023 who subsequently underwent C-POEM. Technical success was defined as completion of all steps of the C-POEM procedure and clinical success as a reduction in the pre-treatment Dakkak and Bennett score to ≤1, or 0 if the pre-treatment score was 1. Results: C-POEM was associated with a technical success of 100% and clinical success of 100% over a median follow up of 2 months (interquartile range 1-8). There was 1 adverse event due to a small mucosal defect and associated leak on barium swallow, which was the result of difficult access during mucosal closure. This was managed conservatively with antibiotics. A step-by-step video demonstration of the procedure is provided. Conclusion: C-POEM offers an alternative upfront therapy for symptomatic cricopharyngeal bar, but should be undertaken by endoscopists with significant experience in third-space endoscopy in view of the difficulty of working within the hypopharynx.

Success rates of fixation techniques on prevention of esophageal stent migration: a systematic review and meta-analysis.

BACKGROUND: Esophageal stenting is an important intervention for managing malignant and benign dysphagia, with stent migration representing a common drawback. This systematic review with meta-analysis aimed to assess the benefit of stent fixation over nonfixation. METHODS: A systematic search was performed in MEDLINE, Cochrane, Scopus, and ClinicalTrials.gov databases until January 2023 for comparative studies evaluating the migration rates of esophageal stents with versus without (control) fixation. The primary outcome was migration rate. Secondary outcomes included adverse event rate. A subgroup analysis stratified the results based on different fixation techniques: suturing, over-the-scope (OTS) clipping, and through-the-scope (TTS) clipping. Meta-analysis was based on a random effects model and the results were reported as odds ratios (ORs) with 95 %CIs. RESULTS: 10 studies (1014 patients) were included. The rate of stent migration was significantly lower after fixation (OR 0.20, 95 %CI 0.11-0.37; I2  = 59 %, P = 0.01). The adverse event rate was similar between fixation and control groups (OR 0.65, 95 %CI 0.28-1.52; I2  = 55 %, P = 0.06). In the subgroup analysis, all fixation techniques remained superior to nonfixation of stents (suturing OR 0.23, 95 %CI 0.10-0.53; OTS clips OR 0.31, 95 %CI 0.17-0.58; TTS clips OR 0.10, 95 %CI 0.03-0.38); however, only the OTS and TTS clip groups achieved nonsignificant heterogeneity (I2  = 0 %, P = 0.67 and P = 0.73, respectively). No difference between techniques was recorded for migration rates. CONCLUSION: Esophageal stent fixation was associated with significantly lower migration rates compared with nonfixation of stents, regardless of fixation technique and stenting indication.

Unraveling the Mechanisms of Vestibular Neuron Formation from Human Induced Pluripotent Stem Cells.

The development of in vitro models that accurately recapitulate the complex cellular and molecular interactions of the inner ear is crucial for understanding inner ear development, function, and disease. In this study, we utilized a customized microfluidic platform to generate human induced pluripotent stem cell (hiPSC)-derived three-dimensional otic sensory neurons (OSNs). hiPSC-derived otic neuronal progenitors (ONPs) were cultured in hydrogel-embedded microfluidic channels over a 40-day period. Careful modulation of Wnt and Shh signaling pathways was used to influence dorsoventral patterning and direct differentiation toward a vestibular neuron lineage. After validating the microfluidic platform, OSN spheroid transcription factor and protein expression were assessed using real-time quantitative polymerase chain reaction (RT-qPCR), immunocytochemistry, and flow cytometry. The results demonstrated the successful differentiation of hiPSCs into ONPs and subsequent divergent differentiation into vestibular neuronal lineages, as evidenced by the expression of characteristic markers. Overall, our microfluidic platform provides a physiologically relevant environment for the culture and differentiation of hiPSCs, offering a valuable tool for studying inner ear development, disease and drug screening, and regenerative medicine applications.

Endoscopic Management of Dysplastic Barrett's Oesophagus and Early Oesophageal Adenocarcinoma.

Barrett's oesophagus is a pathological condition whereby the normal oesophageal squamous mucosa is replaced by specialised, intestinal-type metaplasia, which is strongly linked to chronic gastro-oesophageal reflux. A correct endoscopic and histological diagnosis is pivotal in the management of Barrett's oesophagus to identify patients who are at high risk of progression to neoplasia. The presence and grade of dysplasia and the characteristics of visible lesions within the mucosa of Barrett's oesophagus are both important to guide the most appropriate endoscopic therapy. In this review, we provide an overview on the management of Barrett's oesophagus, with a particular focus on recent advances in the diagnosis and recommendations for endoscopic therapy to reduce the risk of developing oesophageal adenocarcinoma.

Metabolic and Bariatric Endoscopy: A Mini-Review.

We are currently in a worldwide obesity pandemic, which is one of the most significant health problems of the 21st century. As the prevalence of obesity continues to rise, new and innovate treatments are becoming available. Metabolic and bariatric endoscopic procedures are exciting new areas of gastroenterology that have been developed as a direct response to the obesity crisis. These novel interventions offer a potentially reversible, less invasive, safer, and more cost-effective method of tackling obesity compared to traditional bariatric surgery. Minimally invasive endoscopic treatments are not entirely novel, but as technology has rapidly improved, many of the procedures have been proven to be extremely effective for weight loss and metabolic health, based on high-quality clinical trial data. This mini-review examines the existing evidence for the most prominent metabolic and bariatric procedures, followed by a discussion on the future trajectory of this emerging subspecialty.

Localised intestinal Kaposi sarcoma in a patient with non-coeliac seronegative villous atrophy.

Seronegative villous atrophy (SNVA) is a diagnostic challenge for gastroenterologists, which is defined by villous atrophy and negative coeliac serology. Non-coeliac forms of SNVA, such as autoimmune enteropathy, can be life-threatening leading to intractable diarrhoea and severe malabsorption that require systemic immunosuppression. When all known causes have been excluded, it is termed idiopathic villous atrophy (IVA). We present a case of non-coeliac SNVA complicated by Kaposi sarcoma (KS). A previously well HIV-negative man in his 30s presented with a 4-month history of watery diarrhoea and 25 kg weight loss. After prolonged investigation, he was diagnosed with non-coeliac SNVA without an identified aetiology that would be consistent with IVA. Clinical recovery was achieved with parenteral nutrition for type II intestinal failure and immunosuppression using high-dose corticosteroids. On subsequent gastroscopy, he was diagnosed with localised intestinal KS prompting cessation of all immunosuppression but remained in clinical remission.

Lynch syndrome: from detection to treatment.

Lynch syndrome (LS) is an inherited cancer predisposition syndrome associated with high lifetime risk of developing tumours, most notably colorectal and endometrial. It arises in the context of pathogenic germline variants in one of the mismatch repair genes, that are necessary to maintain genomic stability. LS remains underdiagnosed in the population despite national recommendations for empirical testing in all new colorectal and endometrial cancer cases. There are now well-established colorectal cancer surveillance programmes, but the high rate of interval cancers identified, coupled with a paucity of high-quality evidence for extra-colonic cancer surveillance, means there is still much that can be achieved in diagnosis, risk-stratification and management. The widespread adoption of preventative pharmacological measures is on the horizon and there are exciting advances in the role of immunotherapy and anti-cancer vaccines for treatment of these highly immunogenic LS-associated tumours. In this review, we explore the current landscape and future perspectives for the identification, risk stratification and optimised management of LS with a focus on the gastrointestinal system. We highlight the current guidelines on diagnosis, surveillance, prevention and treatment and link molecular disease mechanisms to clinical practice recommendations.

Application of supervised machine learning algorithms for the evaluation of utricular function on patients with Meniere's disease: utilizing subjective visual vertical and ocular-vestibular-evoked myogenic potentials.

BACKGROUND: Research on the otolith organs remains inconclusive. OBJECTIVES: This study seeks to further elucidate utricular function in patients with Meniere's disease (MD) in three ways: (1) We aimed to disambiguate the role of the Subjective Visual Vertical (SVV) and Ocular Vestibular Evoked Myogenic Potential (o-VEMP) tests regarding which utricular subsystem each is measuring. (2) We sought to characterize the acute and chronic state of MD by identifying differences in the relationship of SVV and o-VEMP results across patients with acute and chronic MD. (3) We attempted to find a machine-learning algorithm that could predict acute versus chronic MD using SVV and o-VEMP. METHODS: A prospective study with ninety subjects. RESULTS: (1) SVV and o-VEMP tests were found to have a moderate linear relationship in patients with acute MD, suggesting each test measures a different utricular subsystem. (2) Regression analyses statistically differed across the two patient populations, suggesting that SVV results were normalized in chronic MD patients. (3) Logistic regression and Naïve Bayes algorithms were found to predict acute and chronic MD accurately. SIGNIFICANCE: A better understanding of what diagnostic tests measure will lead to a better classification system for MD and more targeted treatment options in the future.

Intralesional application of ribavirin in two American flamingos (Phoenicopterus ruber) with poxvirus infection.

We report the successful treatment of poxvirus lesions in two juvenile American flamingos (Phoenicopterus ruber) with experimental low-dose intralesional ribavirin injection. In the first flamingo, the size and location of a beak verrucosity interfered with feeding, and after multiple surgical interventions, an experimental therapy of low-dose intralesional ribavirin was implemented with close blood parameter monitoring to minimize any potential side effects due to systemic antiviral administration. The second flamingo had a poxvirus lesion on the tibiotarsus, which recurred after unsuccessful conservative medical treatment and surgical intervention and a course of intralesional ribavirin therapy was implemented. Regression of the lesions in both flamingos commenced within 3 days of ribavirin treatment resulting in complete resolution within 6 weeks of onset of ribavirin treatment.

Bridging the electrode-neuron gap: finite element modeling of in vitro neurotrophin gradients to optimize neuroelectronic interfaces in the inner ear.

Although cochlear implant (CI) technology has allowed for the partial restoration of hearing over the last few decades, persistent challenges (e.g., poor performance in noisy environments and limited ability to decode intonation and music) remain. The "electrode-neuron gap" is inherent to these challenges and poses the most significant obstacle to advancing past the current plateau in CI performance. We propose the development of a "neuro-regenerative nexus"-a biological interface that doubly preserves native spiral ganglion neurons (SGNs) while precisely directing the growth of neurites arising from transplanted human pluripotent stem cell (hPSC)-derived otic neuronal progenitors (ONPs) toward the native SGN population. We hypothesized that the Polyhedrin Delivery System (PODS®-recombinant human brain-derived neurotrophic factor [rhBDNF]) could stably provide the adequate BDNF concentration gradient to hPSC-derived late-stage ONPs to facilitate otic neuronal differentiation and directional neurite outgrowth. To test this hypothesis, a finite element model (FEM) was constructed to simulate BDNF concentration profiles generated by PODS®-rhBDNF based on initial concentration and culture device geometry. For biological validation of the FEM, cell culture experiments assessing survival, differentiation, neurite growth direction, and synaptic connections were conducted using a multi-chamber microfluidic device. We were able to successfully generate the optimal BDNF concentration gradient to enable survival, neuronal differentiation toward SGNs, directed neurite extension of hPSC-derived SGNs, and synaptogenesis between two hPSC-derived SGN populations. This proof-of-concept study provides a step toward the next generation of CI technology. STATEMENT OF SIGNIFICANCE: Our study demonstrates that the generation of in vitro neurotrophin concentration gradients facilitates survival, neuronal differentiation toward auditory neurons, and directed neurite extension of human pluripotent stem cell-derived auditory neurons. These findings are indispensable to designing a bioactive cochlear implant, in which stem cell-derived neurons are integrated into a cochlear implant electrode strip, as the strategy will confer directional neurite growth from the transplanted cells in the inner ear. This study is the first to present the concept of a "neuro-regenerative nexus" congruent with a bioactive cochlear implant to eliminate the electrode-neuron gap-the most significant barrier to next-generation cochlear implant technology.

Sunscreens: UV filters to protect us: Part 2-Increasing awareness of UV filters and their potential toxicities to us and our environment.

BACKGROUND: Sunscreens are topical preparations containing one or more compounds that filter, block, reflect, scatter, or absorb ultraviolet (UV) light. Part 2 of this review focuses on the environmental, ecological effects and human toxicities that have been attributed to UV filters. METHODS: Literature review using NIH databases (eg, PubMed and Medline), FDA and EPA databases, Google Scholar, the Federal Register, and the Code of Federal Regulations (CFR). LIMITATIONS: This was a retrospective literature review that involved many different types of studies across a variety of species. Comparison between reports is limited by variations in methodology and criteria for toxicity. CONCLUSIONS: In vivo and in vitro studies on the environmental and biological effects of UV filters show a wide array of unanticipated adverse effects on the environment and exposed organisms. Coral bleaching receives considerable attention from the lay press, but the scientific literature identifies potential toxicities of endocrine, neurologic, neoplastic and developmental pathways. These effects harm a vast array of aquatic and marine biota, while almost no data supports human toxicity at currently used quantities (with the exception of contact allergy). Much of these data are from experimental studies or field observations; more controlled environmental studies and long-term human use data are limited. Several jurisdictions have prohibited specific UV filters, but this does not adequately address the dichotomy of the benefits of photoprotection vs lack of eco-friendly, safe, and FDA-approved alternatives.

Lionfish envenomation in Caribbean and Atlantic waters: Climate change and invasive species.

The concept of emerging diseases is well understood; however, the concept of emerging injuries is not. We describe the introduction of two species of lionfish, native to the Indian and Pacific Oceans, into the warm shallow coastal waters of the Western Atlantic Ocean and the Caribbean Sea. Lionfish thrive in the same coastal waters that attract recreational swimmers, snorkelers, and divers. Because lionfish have ornate colors, people often swim close to have a better look. Lionfish have venomous spines and, in a defensive reaction, frequently envenomate curious humans. The fish are voracious predators and disrupt the coral ecosystems of the Atlantic. Furthermore, their range is spreading through a combination of lack of natural predators and the expansion of hospitable warm waters into higher latitudes as part of climate change.

Laser stabilization to neutral Yb in a discharge with polarization-enhanced frequency modulation spectroscopy.

Isotope selective optical excitation of atoms is important for experiments with neutral atoms, metrology, and work with trapped ions, including quantum information processing. Polarization-enhanced absorption spectroscopy is used to frequency stabilize a tunable external cavity laser diode system at 398.9 nm for isotope selective photoionization of neutral Yb atoms. This spectroscopy technique is used to measure isotope resolved dispersive features from transitions within a see-through configuration ytterbium hollow-cathode discharge lamp. This Doppler-free dichroic polarization spectroscopy is realized by retro-reflecting a laser beam through the discharge and analyzing the polarization dependent absorption with balanced detection. The spectroscopy signal is recovered using lock-in detection of frequency modulation induced by current modulation of the external cavity laser diode. Here, we show an order of magnitude improvement in the long-term stability using polarization-enhanced absorption spectroscopy of Yb compared to polarization spectroscopy.