Neural and sensory basis of homing behavior in the invasive cane toad, Rhinella marina.

The behavioral, sensory, and neural bases of vertebrate navigation are primarily described in mammals and birds. However, we know much less about navigational abilities and mechanisms of vertebrates that move on smaller scales, such as amphibians. To address this knowledge gap, we conducted an extensive field study on navigation in the cane toad, Rhinella marina. First, we performed a translocation experiment to describe how invasive toads in Hawai'i navigate home following displacements of up to one kilometer. Next, we tested the effect of olfactory and magnetosensory manipulations on homing, as these senses are most commonly associated with amphibian navigation. We found that neither ablation alone prevents homing, suggesting that toad navigation is multimodal. Finally, we tested the hypothesis that the medial pallium, the amphibian homolog to the hippocampus, is involved in homing. By comparing neural activity across homing and non-homing toads, we found evidence supporting the involvement of the medial pallium, lateral pallium, and septum in navigation, suggesting a conservation of neural structures supporting navigation across vertebrates. Our study lays the foundation to understand the behavioral, sensory, and neural bases of navigation in amphibians and to further characterize the evolution of behavior and neural structures in vertebrates.

Water availability and temperature as modifiers of evaporative water loss in tropical frogs.

Water plays a notable role in the ecology of most terrestrial organisms due to the risks associated with water loss. Specifically, water loss in terrestrial animals happens through evaporation across respiratory tissues or epidermis. Amphibians are ideal systems for studying how abiotic factors impact water loss since their bodies often respond quickly to environmental changes. While the effect of temperature on water loss is well known across many taxa, we are still learning how temperature in combination with humidity or water availability affects water loss. Here, we tested how standing water sources (availability) and temperature (26 and 36°C) together affect water loss in anuran amphibians using a Bayesian framework. We also present a conceptual model for considering how water availability and temperature may interact, resulting in body mass changes. After accounting for phylogenetic and time autocorrelation, we determined how different variables (water loss and uptake rates, temperature, and body size) affect body mass in three species of tropical frogs (Rhinella marina, Phyllobates terribilis, and Xenopus tropicalis). We found that all variables impacted body mass changes with greater similarities between P. terribilis and X. tropicalis, but only temperature showed a notable effect in P. terribilis. Furthermore, we describe how the behavior of P. terribilis might affect its water budget. This study shows how organisms might manage water budgets across different environments and is important for developing our models of evaporative water loss and species distributions.

Tadpoles rely on mechanosensory stimuli for communication when visual capabilities are poor.

The ways in which animals sense the world changes throughout development. For example, young of many species have limited visual capabilities, but still make social decisions, likely based on information gathered through other sensory modalities. Poison frog tadpoles display complex social behaviors that have been suggested to rely on vision despite a century of research indicating tadpoles have poorly-developed visual systems relative to adults. Alternatively, other sensory modalities, such as the lateral line system, are functional at hatching in frogs and may guide social decisions while other sensory systems mature. Here, we examined development of the mechanosensory lateral line and visual systems in tadpoles of the mimic poison frog (Ranitomeya imitator) that use vibrational begging displays to stimulate egg feeding from their mothers. We found that tadpoles hatch with a fully developed lateral line system. While begging behavior increases with development, ablating the lateral line system inhibited begging in pre-metamorphic tadpoles, but not in metamorphic tadpoles. We also found that the increase in begging and decrease in reliance on the lateral line co-occurs with increased retinal neural activity and gene expression associated with eye development. Using the neural tracer neurobiotin, we found that axonal innervations from the eye to the brain proliferate during metamorphosis, with few retinotectal connections in recently-hatched tadpoles. We then tested visual function in a phototaxis assay and found tadpoles prefer darker environments. The strength of this preference increased with developmental stage, but eyes were not required for this behavior, possibly indicating a role for the pineal gland. Together, these data suggest that tadpoles rely on different sensory modalities for social interactions across development and that the development of sensory systems in socially complex poison frog tadpoles is similar to that of other frog species.

What is the rate of definitive stoma after subtotal colectomy for inflammatory bowel disease? A nationwide study of 1860 patients.

AIM: Some patients with inflammatory bowel disease (IBD) require subtotal colectomy (STC) with ileostomy. The recent literature reports a significant number of patients who do not undergo subsequent surgery and are resigned to living with a definitive stoma. The aim of this work was to analyse the rate of definitive stoma and the cumulative incidence of secondary reconstructive surgery after STC for IBD in a large national cohort study. METHOD: A national retrospective study (2013-2021) was conducted on prospectively collected data from the French Medical Information System Database (PMSI). All patients undergoing STC in France were included. The association between definitive stoma and potential risk factors was studied using univariate and multivariate analyses. RESULTS: A total of 1860 patients were included (age 45 ± 9 years; median follow-up 30 months). Of these, 77% (n = 1442) presented with ulcerative colitis. Mortality and morbidity at 90 days after STC were 5% (n = 100) and 47% (n = 868), respectively. Reconstructive surgery was identified in 1255 patients (67%) at a mean interval of 7 months from STC. Seveny-four per cent (n = 932) underwent a completion proctectomy with ileal pouch anal anastomosis and 26% (n = 323) an ileorectal anastomosis. Six hundred and five (33%) patients with a definitive stoma had an abdominoperineal resection (n = 114; 19%) or did not have any further surgical procedure (n = 491; 81%). Independent risk factors for definitive stoma identified in multivariate analysis were older age, Crohn's disease, colorectal neoplasia, postoperative complication after STC, laparotomy and a low-volume hospital. CONCLUSION: We found that 33% of patients undergoing STC with ileostomy for IBD had definitive stoma. Modifiable risk factors for definitive stoma were laparotomy and a low-volume hospital.

Genome Assembly of the Dyeing Poison Frog Provides Insights into the Dynamics of Transposable Element and Genome-Size Evolution.

Genome size varies greatly across the tree of life and transposable elements are an important contributor to this variation. Among vertebrates, amphibians display the greatest variation in genome size, making them ideal models to explore the causes and consequences of genome size variation. However, high-quality genome assemblies for amphibians have, until recently, been rare. Here, we generate a high-quality genome assembly for the dyeing poison frog, Dendrobates tinctorius. We compare this assembly to publicly available frog genomes and find evidence for both large-scale conserved synteny and widespread rearrangements between frog lineages. Comparing conserved orthologs annotated in these genomes revealed a strong correlation between genome size and gene size. To explore the cause of gene-size variation, we quantified the location of transposable elements relative to gene features and find that the accumulation of transposable elements in introns has played an important role in the evolution of gene size in D. tinctorius, while estimates of insertion times suggest that many insertion events are recent and species-specific. Finally, we carry out population-scale mobile-element sequencing and show that the diversity and abundance of transposable elements in poison frog genomes can complicate genotyping from repetitive element sequence anchors. Our results show that transposable elements have clearly played an important role in the evolution of large genome size in D. tinctorius. Future studies are needed to fully understand the dynamics of transposable element evolution and to optimize primer or bait design for cost-effective population-level genotyping in species with large, repetitive genomes.

Pavement ant extract is a chemotaxis repellent for C. elegans.

Ant behavior relies on a collection of natural products, from following trail pheromones during foraging to warding off potential predators. How nervous systems sense these compounds to initiate a behavioral response remains unclear. Here, we used Caenorhabditis elegans chemotaxis assays to investigate how ant compounds are detected by heterospecific nervous systems. We found that C. elegans avoid extracts of the pavement ant ( Tetramorium immigrans ) and either osm-9 or tax-4 ion channels are required for this response. These experiments were conducted in an undergraduate laboratory course, demonstrating that new insights into interspecies interactions can be generated through genuine research experiences in a classroom setting.

Rectovaginal Fistula: What is the Role of Martius Flap and Gracilis Muscle Interposition in the Therapeutic Strategy?

BACKGROUND: While numerous treatments exist for management of rectovaginal fistula, none has demonstrated its superiority. The role of diverting stoma remains controversial. Few series include Martius flap in the armamentarium. OBJECTIVE: Determine the role of gracilis muscle interposition and Martius flap in the surgical management of rectovaginal fistula. DESIGN: Retrospective cohort study of a pooled prospectively maintained database from 3 centers. SETTINGS/PATIENTS: All consecutive eligible patients with rectovaginal fistula undergoing Martius flap and gracilis muscle interposition were included from 2001 to 2022. MAIN OUTCOMES: Success was defined by absence of stoma and rectovaginal fistula. RESULTS: Sixty-two patients were included with 55 Martius flap and 24 gracilis muscle interposition performed after failures of 164 initial procedures. Total length of stay was longer for gracilis muscle interposition by 2 days (p = 0.01) without a significant difference in severe morbidity (20% vs. 12%, p = 0.53). 27% of Martius flap were performed without stoma, without impact on overall morbidity (p = 0.763). Per-patient immediate success rates were not significantly different between groups (35% vs. 31%, p = 1.0). Success of gracilis muscle interposition after failure of Martius flap was not significantly different from an initial gracilis muscle interposition (p = 1.0). The immediate success rate rose to 49.4% (49% vs. 50%, p = 1.0) after simple perineal procedures. After a median follow-up of 23 months, there was no significant difference detected in success rate between the two procedures (69% vs. 69%, p = 1.0). Smoking was the only negative predictive factor (p = 0.02). LIMITATIONS: By its retrospective nature, this study is limited in its comparison. CONCLUSION: This novel comparison between Martius flap and gracilis muscle interposition suggests that Martius flap presents several advantages, including shorter length of stay, similar morbidity, and success. Proximal diversion via a stoma for Martius flap does not appear mandatory. Gracilis muscle interposition could be reserved as a salvage procedure after Martius flap failure. See Video Abstract.

Influence of neoadjuvant treatment strategy on perioperative outcomes in locally advanced rectal cancer.

AIM: Neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer facilitates tumour downstaging and complete pathological response (pCR). The goal of neoadjuvant systemic chemotherapy (total neoadjuvant chemotherapy, TNT) is to further improve local and systemic control. While some patients forgo surgery, total mesorectal excision (TME) remains the standard of care. While TNT appears to be noninferior to nCRT with respect to short-term oncological outcomes few data exist on perioperative outcomes. Perioperative morbidity including anastomotic leaks is associated with a negative effect on oncological outcomes, probably due to a delay in proceeding to adjuvant therapy. Thus, we aimed to compare conversion rates, rates of sphincter-preserving surgery and anastomosis formation rates in patients undergoing rectal resection after either TNT or standard nCRT. METHODS: An institutional colorectal oncology database was searched from January 2018 to July 2023. Inclusion criteria comprised patients with histologically confirmed rectal cancer who had undergone neoadjuvant therapy and TME. Exclusion criteria comprised patients with a noncolorectal primary, those operated on emergently or who had local excision only. Outcomes evaluated included rates of conversion to open, sphincter-preserving surgery, anastomosis formation and anastomotic leak. RESULTS: A total of 119 patients were eligible for inclusion (60 with standard nCRT, 59 with TNT). There were no differences in rates of sphincter preservation or primary anastomosis formation between the groups. However, a significant increase in conversion to open (p = 0.03) and anastomotic leak (p = 0.03) was observed in the TNT cohort. CONCLUSION: In this series TNT appears to be associated with higher rates of conversion to open surgery and higher anastomotic leak rates. While larger studies will be required to confirm these findings, these factors should be considered alongside oncological benefits when selecting treatment strategies.

Heterogeneous lineage-specific arginine deiminase expression within dental microbiome species.

Arginine catabolism by the bacterial arginine deiminase system (ADS) has anticariogenic properties through the production of ammonia, which modulates the pH of the oral environment. Given the potential protective capacity of the ADS pathway, the exploitation of ADS-competent oral microbes through pre- or probiotic applications is a promising therapeutic target to prevent tooth decay. To date, most investigations of the ADS in the oral cavity and its relation to caries have focused on indirect measures of activity or on specific bacterial groups, yet the pervasiveness and rate of expression of the ADS operon in diverse mixed microbial communities in oral health and disease remain an open question. Here, we use a multivariate approach, combining ultra-deep metatranscriptomic sequencing with paired metataxonomic and in vitro citrulline quantification to characterize the microbial community and ADS operon expression in healthy and late-stage cavitated teeth. While ADS activity is higher in healthy teeth, we identify multiple bacterial lineages with upregulated ADS activity on cavitated teeth that are distinct from those found on healthy teeth using both reference-based mapping and de novo assembly methods. Our dual metataxonomic and metatranscriptomic approach demonstrates the importance of species abundance for gene expression data interpretation and that patterns of differential expression can be skewed by low-abundance groups. Finally, we identify several potential candidate probiotic bacterial lineages within species that may be useful therapeutic targets for the prevention of tooth decay and propose that the development of a strain-specific, mixed-microbial probiotic may be a beneficial approach given the heterogeneity of taxa identified here across health groups. IMPORTANCE: Tooth decay is the most common preventable chronic disease, affecting more than two billion people globally. The development of caries on teeth is primarily a consequence of acid production by cariogenic bacteria that inhabit the plaque microbiome. Other bacterial strains in the oral cavity may suppress or prevent tooth decay by producing ammonia as a byproduct of the arginine deiminase metabolic pathway, increasing the pH of the plaque biofilm. While the benefits of arginine metabolism on oral health have been extensively documented in specific bacterial groups, the prevalence and consistency of arginine deiminase system (ADS) activity among oral bacteria in a community context remain an open question. In the current study, we use a multi-omics approach to document the pervasiveness of the expression of the ADS operon in both health and disease to better understand the conditions in which ADS activity may prevent tooth decay.

A toxic environment selects for specialist microbiome in poison frogs.

Shifts in microbiome community composition can have large effects on host health. It is therefore important to understand how perturbations, like those caused by the introduction of exogenous chemicals, modulate microbiome community composition. In poison frogs within the family Dendrobatidae, the skin microbiome is exposed to the alkaloids that the frogs sequester from their diet and use for defense. Given the demonstrated antimicrobial effects of these poison frog alkaloids, these compounds may be structuring the skin microbial community. To test this, we first characterized microbial communities from chemically defended and closely related non-defended frogs from Ecuador. Then we conducted a laboratory experiment to monitor the effect of the alkaloid decahydroquinoline (DHQ) on the microbiome of a single frog species. In both the field and lab experiments, we found that alkaloid-exposed microbiomes are more species rich and phylogenetically diverse, with an increase in rare taxa. To better understand the strain-specific behavior in response to alkaloids, we cultured microbial strains from poison frog skin and found the majority of strains exhibited either enhanced growth or were not impacted by the addition of DHQ. Additionally, stable isotope tracing coupled to nanoSIMS suggests that some of these strains are able to metabolize DHQ. Taken together, these data suggest that poison frog chemical defenses open new niches for skin-associated microbes with specific adaptations, including the likely metabolism of alkaloids, that enable their survival in this toxic environment. This work helps expand our understanding of how exposure to exogenous compounds like alkaloids can impact host microbiomes.

Supragingival mycobiome of HIV-exposed-but-uninfected children reflects a stronger correlation with caries-free-associated taxa compared to HIV-infected or uninfected children.

IMPORTANCE: Globally, caries is among the most frequent chronic childhood disease, and the fungal component of the microbial community responsible is poorly studied despite evidence that fungi contribute to increased acid production exacerbating enamel demineralization. HIV infection is another global health crisis. Perinatal HIV exposure with infection are caries risk factors; however, the caries experience in the context of perinatal HIV exposure without infection is less clear. Using high-throughput amplicon sequencing, we find taxonomic differences that become pronounced during late-stage caries. Notably, we show a stronger correlation with health-associated taxa for HIV-exposed-but-uninfected children when compared to unexposed and uninfected children. This aligns with a lower incidence of caries in primary teeth at age 6 or less for exposed yet uninfected children. Ultimately, these findings could contribute to improved risk assessment, intervention, and prevention strategies such as biofilm disruption and the informed design of pro-, pre-, and synbiotic oral therapies.

Selection on Visual Opsin Genes in Diurnal Neotropical Frogs and Loss of the SWS2 Opsin in Poison Frogs.

Amphibians are ideal for studying visual system evolution because their biphasic (aquatic and terrestrial) life history and ecological diversity expose them to a broad range of visual conditions. Here, we evaluate signatures of selection on visual opsin genes across Neotropical anurans and focus on three diurnal clades that are well-known for the concurrence of conspicuous colors and chemical defense (i.e., aposematism): poison frogs (Dendrobatidae), Harlequin toads (Bufonidae: Atelopus), and pumpkin toadlets (Brachycephalidae: Brachycephalus). We found evidence of positive selection on 44 amino acid sites in LWS, SWS1, SWS2, and RH1 opsin genes, of which one in LWS and two in RH1 have been previously identified as spectral tuning sites in other vertebrates. Given that anurans have mostly nocturnal habits, the patterns of selection revealed new sites that might be important in spectral tuning for frogs, potentially for adaptation to diurnal habits and for color-based intraspecific communication. Furthermore, we provide evidence that SWS2, normally expressed in rod cells in frogs and some salamanders, has likely been lost in the ancestor of Dendrobatidae, suggesting that under low-light levels, dendrobatids have inferior wavelength discrimination compared to other frogs. This loss might follow the origin of diurnal activity in dendrobatids and could have implications for their behavior. Our analyses show that assessments of opsin diversification in across taxa could expand our understanding of the role of sensory system evolution in ecological adaptation.

Tissue-specific in vivo transformation of plasmid DNA in Neotropical tadpoles using electroporation.

Electroporation is an increasingly common technique used for exogenous gene expression in live animals, but protocols are largely limited to traditional laboratory organisms. The goal of this protocol is to test in vivo electroporation techniques in a diverse array of tadpole species. We explore electroporation efficiency in tissue-specific cells of five species from across three families of tropical frogs: poison frogs (Dendrobatidae), cryptic forest/poison frogs (Aromobatidae), and glassfrogs (Centrolenidae). These species are well known for their diverse social behaviors and intriguing physiologies that coordinate chemical defenses, aposematism, and/or tissue transparency. Specifically, we examine the effects of electrical pulse and injection parameters on species- and tissue-specific transfection of plasmid DNA in tadpoles. After electroporation of a plasmid encoding green fluorescent protein (GFP), we found strong GFP fluorescence within brain and muscle cells that increased with the amount of DNA injected and electrical pulse number. We discuss species-related challenges, troubleshooting, and outline ideas for improvement. Extending in vivo electroporation to non-model amphibian species could provide new opportunities for exploring topics in genetics, behavior, and organismal biology.

Impact of HIV on the Oral Microbiome of Children Living in Sub-Saharan Africa, Determined by Using an rpoC Gene Fragment Metataxonomic Approach.

Children living with HIV have a higher prevalence of oral diseases, including caries, but the mechanisms underlying this higher prevalence are not well understood. Here, we test the hypothesis that HIV infection is associated with a more cariogenic oral microbiome, characterized by an increase in bacteria involved in the pathogenesis of caries. We present data generated from supragingival plaques collected from 484 children representing three exposure groups: (i) children living with HIV (HI), (ii) children who were perinatally exposed but uninfected (HEU), and (iii) unexposed and therefore uninfected children (HUU). We found that the microbiome of HI children is distinct from those of HEU and HUU children and that this distinction is more pronounced in diseased teeth than healthy teeth, suggesting that the impact of HIV is more severe as caries progresses. Moreover, we report both an increase in bacterial diversity and a decrease in community similarity in our older HI cohort compared to our younger HI cohort, which may in part be a prolonged effect of HIV and/or its treatment. Finally, while Streptococcus mutans is often a dominant species in late-stage caries, it tended to be found at lower frequency in our HI cohort than in other groups. Our results highlight the taxonomic diversity of the supragingival plaque microbiome and suggest that broad and increasingly individualistic ecological shifts are responsible for the pathogenesis of caries in children living with HIV, coupled with a diverse and possibly severe impact on known cariogenic taxa that potentially exacerbates caries. IMPORTANCE Since its recognition as a global epidemic in the early 1980s, approximately 84.2 million people have been diagnosed with HIV and 40.1 million people have died from AIDS-related illnesses. The development and increased global availability of antiretroviral treatment (ART) regimens have dramatically reduced the mortality rate of HIV and AIDS, yet approximately 1.5 million new infections were reported in 2021, 51% of which are in sub-Saharan Africa. People living with HIV have a higher prevalence of caries and other chronic oral diseases, the mechanisms of which are not well understood. Here, we used a novel genetic approach to characterize the supragingival plaque microbiome of children living with HIV and compared it to the microbiomes of uninfected and perinatally exposed children to better understand the role of oral bacteria in the etiology of tooth decay in the context of HIV exposure and infection.

Activity of FoxP2-positive neurons correlate with tadpole begging behavior.

Motor function is a critical aspect of social signaling in a wide range of taxa. The transcription factor FoxP2 is well studied in the context of vocal communication in humans, mice, and songbirds, but its role in regulating social signaling in other vertebrate taxa is unclear. We examined the distribution and activity of FoxP2-positive neurons in tadpoles of the mimetic poison frog (Ranitomeya imitator). In this species, tadpoles are reared in isolated plant nurseries and are aggressive to other tadpoles. Mothers provide unfertilized egg meals to tadpoles that perform a begging display by vigorously vibrating back and forth. We found that FoxP2 is widely distributed in the tadpole brain and parallels the brain distribution in mammals, birds, and fishes. We then tested the hypothesis that FoxP2-positive neurons would have differential activity levels in begging or aggression contexts compared to non-social controls. We found that FoxP2-positive neurons showed increased activation in the striatum and cerebellum only during begging. Overall, this work suggests a generalizable role for FoxP2 in social signaling across terrestrial vertebrates.

Home security cameras as a tool for behavior observations and science equity.

Reliably capturing transient animal behavior in the field and laboratory remains a logistical and financial challenge, especially for small ectotherms. Here, we present a camera system that is affordable, accessible, and suitable to monitor small, cold-blooded animals historically overlooked by commercial camera traps, such as small amphibians. The system is weather-resistant, can operate offline or online, and allows collection of time-sensitive behavioral data in laboratory and field conditions with continuous data storage for up to four weeks. The lightweight camera can also utilize phone notifications over Wi-Fi so that observers can be alerted when animals enter a space of interest, enabling sample collection at proper time periods. We present our findings, both technological and scientific, in an effort to elevate tools that enable researchers to maximize use of their research budgets. We discuss the relative affordability of our system for researchers in South America, which is home to the largest population of ectotherm diversity.

Argentine ant extract induces an osm-9 dependent chemotaxis response in C. elegans.

Many ant species are equipped with chemical defenses, although how these compounds impact nervous system function is unclear. Here, we examined the utility of Caenorhabditis elegans chemotaxis assays for investigating how ant chemical defense compounds are detected by heterospecific nervous systems. We found that C. elegans respond to extracts from the invasive Argentine Ant ( Linepithema humile ) and the osm-9 ion channel is required for this response. Divergent strains varied in their response to L. humile extracts, suggesting genetic variation underlying chemotactic responses. These experiments were conducted by an undergraduate laboratory course, highlighting how C. elegans chemotaxis assays in a classroom setting can provide genuine research experiences and reveal new insights into interspecies interactions.

Albino Xenopus laevis tadpoles prefer dark environments compared to wild type.

Tadpoles display preferences for different environments but the sensory modalities that govern these choices are not well understood. Here, we examined light preferences and associated sensory mechanisms of albino and wild-type Xenopus laevis tadpoles. We found that albino tadpoles spent more time in darker environments compared to the wild type, although they showed no differences in overall activity. This preference persisted when the tadpoles had their optic nerve severed or pineal glands removed, suggesting these sensory systems alone are not necessary for phototaxis. These experiments were conducted by an undergraduate laboratory course, highlighting how X. laevis tadpole behavior assays in a classroom setting can reveal new insights into animal behavior.

Ambulatory appendectomy for acute appendicitis: Can we treat all the patients? A prospective study of 451 consecutive ambulatory appendectomies out of nearly 2,000 procedures.

BACKGROUND: Acute appendicitis represents the leading cause of acute gastrointestinal disorders, but only a small series regarding ambulatory appendectomies are available. The aim of this study was to report the results of ambulatory (day-case) appendectomy for acute appendicitis in a large consecutive cohort and to improve selection criteria in order to extend the indications. METHODS: All appendectomy procedures for acute appendicitis (March 2013 to June 2020) were included retrospectively. Criteria to select patients eligible for ambulatory appendectomy were based on our clinico-radiological St-Antoine's score ≥4. RESULTS: In total, 1,730 consecutive patients had an appendectomy for acute appendicitis: 1,279 (74%) in conventional settings and 451 (26%) in ambulatory settings. In the conventional group, 360 (28%) patients had surgery deferred to the next morning, whereas in the ambulatory group, 309 patients (70%) were readmitted the next morning (P < .0001). In the ambulatory group, 376 (83%) patients satisfied the criteria (score ≥4), and 90.9% were discharged on postoperative day 0. Rates of unplanned consultation and readmission were not significantly different (5.1% vs 6.6% P = .243). Multivariate analysis of the entire cohort confirmed absence of radiological perforation as highly predictive of early discharge (odds ratio = 6.073). In our cohort, these patients had an early discharge rate of 86.4% compared to 90.2% in those with a St-Antoine's score ≥4. Considering only radiological evidence of perforation as a selection criterion for ambulatory appendectomy, 581 more patients would be eligible for ambulatory surgery (+60%). CONCLUSION: Ambulatory surgery for acute appendicitis based on St-Antoine's score is safe. We propose to extend the indication for ambulatory management to all patients without radiological evidence of perforation.

Being and doing anorexia nervosa: An autoethnography of diagnostic identity and performance of illness.

This autoethnography examines my experience of the diagnosis and treatment of anorexia nervosa. Drawing on memory and personal and medical documents relating to inpatient admissions in an adult specialist eating disorder unit, I narrate and analyse my experience in terms of my relationship to the diagnosis of anorexia and the constructions of it I encountered. I show how I came to value an identity based on anorexia and how I learned ways of 'doing' the diagnosis in treatment. This involved me valuing medical markers of illness, including signs of poor health, which became crucial to how I performed my diagnosis and retained the diagnostically-informed sense of self that I valued. I suggest that, ultimately, these diagnostic-dynamics, alongside other effects of long-term inpatient treatment such as detachment from 'normal life', prolonged my struggles with self-starvation. The insights from this autoethnography shed light on potential iatrogenic impacts of diagnosis and treatment for anorexia.