Endoscopic Retrograde Cholangiopancreatography on Pediatric Patients: Experience of a Portuguese Adult Gastroenterology Department.

Introduction: Experience with endoscopic retrograde cholangiopancreatography (ERCP) in the pediatric population is limited. Few medical centers have experts specifically trained in pediatric therapeutic endoscopy. As a result, patients are generally referred to adult endoscopists with high experience in the procedure. The aim of this study was to characterize the experience of an adult endoscopy unit with ERCP on pediatric patients, with a special focus on very young patients. Methods: We retrospectively analyzed indications, technical success rate, final clinical diagnosis, and complications of ERCPs in children <18 years at our tertiary referral hospital center between January 1994 and June 2022. Results: Sixty-five ERCPs were performed on 57 children with a median age of 13 years (range 1-17 years). Eleven ERCPs were performed on 9 patients up to 5 years old. Indications for ERCP were as follows: biliary obstruction (n = 40), mainly due to choledocholithiasis, lithiasic acute pancreatitis (n = 19), recurrent pancreatitis (n = 3), stent extraction (n = 2), and post-operative biliary fistula (n = 1). The cannulation success rate was 95.1%. Therapeutic interventions were performed in 79% of ERCP. All patients were followed up as inpatients. Complications were recorded in two procedures (3.1%), and no procedure-related mortality occurred. Conclusion: In our experience, ERCP in children can be safely performed with high success rates by advanced adult-trained expert endoscopists at a high-volume center.

Introdução: Existe pouca experiência na realização de colangiopancreatografia retrógrada endoscópica (CPRE) na população pediátrica. A maioria dos centros carece de especialistas especificamente treinados em endoscopia terapêutica pediátrica, sendo os doentes geralmente referenciados para Gastroenterologistas de adultos com elevada experiência na técnica. O objectivo deste estudo foi caracterizar a experiência de um departamento de Gastrenterologia de adultos em CPRE pediátrica, com destaque particular nos doentes muito novos. Métodos: Foram analisadas retrospectivamente as indicações, sucesso técnico, diagnósticos e complicações das colangiopancreatografias retrógradas endoscópicas (CPREs) realizadas no nosso hospital terciário em crianças <18 anos, entre Janeiro de 1994 e Junho de 2022. Resultados: Foram realizadas 65 CPREs em 57 crianças com idade mediana 13 anos (1­17 anos). Doze procedimentos foram realizados em 9 crianças com idade até 5 anos. As indicações para CPRE foram: obstrução biliar (n = 40), sobretudo devido a coledocolitíase, pancreatite aguda litiásica (n = 19), pancreatite recorrente (n = 3), extracção de prótese (n = 2) e fístula biliar pós cirurgia (n = 1). A taxa de sucesso de canulação foi 95.4%. Foram realizados procedimentos terapêuticos em 80.0% das CPREs. Todos os doentes foram vigiados em regime de internamento, tendo-se registado complicações em dois exames (3.1%). Não existiram mortes relacionadas com a técnica. Discussão/ Conclusão: A CPRE pode ser realizada na população pediátrica com segurança e elevada taxa de sucesso por Gastrenterologistas de adultos com experiência na técnica, num centro com elevado volume de exames.

Referral for liver transplant following acute variceal bleeding: a multicenter cohort study.

OBJECTIVES: Referral for liver transplant (LT) following acute variceal bleeding (AVB) varies widely. We aimed to characterize and assess its impact on clinical outcomes. METHODS: Observational retrospective cohort including cirrhosis patients with AVB from 3 hospitals in Lisbon, Portugal, from 2018 to 2019. Primary exposure was referral for LT and primary endpoint was all-cause mortality within 2 years of index hospital admission. RESULTS: Among 143 patients, median (IQR) age was 59 (52-72) years and 90 (62.9%) were males. Median (IQR) MELDNa scores on hospital admission and discharge were 15 (11-21) and 13 (10-16), respectively. Overall, 30 (21.0%) patients were assessed for LT, 13 (9.1%) prior to and 17 (11.9%) within 2 years of hospital admission. Overall, 58 (40.6%) patients had at least one potential contra-indication for transplant. LT was performed in 3 (2.1%) patients (among 5 listed). Overall, 34 (23.8%) and 62 (43.4%) patients died at 6 weeks and 2 years post hospital admission, respectively. Following adjustment for confounders, referral for LT was associated with lower 2-year mortality (aHR (95% CI) = 0.20 (0.05-0.85)). CONCLUSION: In a multicenter cohort of cirrhosis patients with AVB, less than a quarter underwent formal LT evaluation. Improved referral for LT following AVB may benefit cirrhosis patients' longer-term mortality.

The genus Bradleya Hornibrook, 1952 (Crustacea: Ostracoda) in South America and adjacent oceanic areas, with description of a new bradleyine genus.

The ostracod genus Bradleya Hornibrook is an important taxon of Cenozoic assemblages, occurring practically in all oceanic regions. The wide distribution both in shallow and deep waters turns Bradleya interesting for studies involving phylogeny and paleoceanography. The present work aims at the study of fossil and recent species in South America and adjacent regions, based on bibliographic review and the restudy of samples from the Brazilian continental margin, the Navidad Formation (lower Miocene) and El Peral Beds (meso-upper Miocene), both cropping out in the Central Chile. The chronostratigraphic, (paleo)bathymetric and (paleo)zoogeographic distribution of the species is reviewed and updated. The bridge composition was studied in all species recorded and revealed to be important taxonomic character. The taxa identified were gathered into three morphological groups: two proposed previously (i.e., the dictyon-group and the arata-group) and a new one in the present work (i.e., the normani-group). The dictyon-group and the arata-group gather deep-sea species, while the normani-group is predominantly neritic, including most of the species of Brazilian margin. Bradleya victorjarai sp. nov. is proposed for the Miocene of Chile, and Bradleya ybate (Bergue et al.) is reassigned to Rigracythere gen. nov. Questionable or misidentified species ascribed to Bradleya are briefly discussed.

Is Metformin Associated with a Lower Prevalence of Polyps, Adenomas, and Colorectal Carcinoma in Patients with Diabetes Mellitus?

PURPOSE: Recent studies suggested a protective role of metformin in the development of colorectal cancer (CRC) and its precursors. We aimed to investigate if metformin was associated with a lower prevalence and number of colorectal polyps in diabetic patients and also adenomas, high-risk adenomas, and CRC. METHODS: Retrospective study on adult patients with diabetes mellitus followed in our hospital with a total colonoscopy between 2015 and 2019, treated with either metformin for > 5 years or other antidiabetic agent (control group). We assessed the number, size, and histopathology examination of proliferative lesions detected on colonoscopy. RESULTS: We included 401 patients aged 69 ± 9 years, 57% males, divided into two groups: treated with metformin (n = 260) and without (n = 141). The number of polyps detected was significantly lower in patients under metformin (p = 0.014). There was a nonsignificant trend towards lower polyp detection rates in the metformin compared to the control group both in unadjusted analysis (50% vs 60%, p = 0.058) and multivariable adjusted analysis (odds ratio [OR] 0.68, 95% confidence interval [CI] 0.43-1.09, p = 0.111). In the latter, we identified male gender (OR 2.24, 95%CI 1.44-3.49, p < 0.001), age (OR 1.35 for every 10 years, 95%CI 1.07-1.71, p = 0.012), glycated hemoglobin value (OR 1.20 for every 1% increase, 95%CI 1.06-1.37, p = 0.005), and hypertension (OR 1.76, 95%CI 1.01-3.08, p = 0.046) as factors associated with a higher prevalence of polyps. We saw no statistically significant differences regarding adenoma (p = 0.231), high-risk adenoma (p = 0.810), and CRC (p = 0.705) diagnoses between groups. CONCLUSION: In our study, metformin was associated with less colorectal polyps in diabetic patients compared to other treatment modalities. We observed a nonsignificant trend towards lower polyp detection rates in the metformin group both in unadjusted and adjusted analyses.

Deciphering the Catalytic Mechanism of Virginiamycin B Lyase with Multiscale Methods and Molecular Dynamics Simulations.

Due to the emergence of antibiotic resistance, the need to explore novel antibiotics and/or novel strategies to counter antibiotic resistance is of utmost importance. In this work, we explored the molecular and mechanistic details of the degradation of a streptogramin B antibiotic by virginiamycin B (Vgb) lyase of Staphylococcus aureus using classical molecular dynamics simulations and multiscale quantum mechanics/molecular mechanics methods. Our results were in line with available experimental kinetic information. Although we were able to identify a stepwise mechanism, in the wild-type enzyme, the intermediate is short-lived, showing a small barrier to decay to the product state. The impact of point mutations on the reaction was also assessed, showing not only the importance of active site residues to the reaction catalyzed by Vgb lyase but also of near positive and negative residues surrounding the active site. Using molecular dynamics simulations, we also predicted the most likely protonation state of the 3-hydroxypicolinic moiety of the antibiotic and the impact of mutants on antibiotic binding. All this information will expand our understanding of linearization reactions of cyclic antibiotics, which are crucial for the development of novel strategies that aim to tackle antibiotic resistance.

Deep-sea mining: using hyperbaric conditions to study the impact of sediment plumes in the subtidal clam Spisula solida.

With the growing interest to exploit mineral resources in the deep-sea, there is the need to establish guidelines and frameworks to support hazard and risk assessment schemes. The present study used a subtidal species of filter-feeding bivalve, the clam Spisula solida, as a proxy to better understand the impacts of sediment plumes in marine organisms under hyperbaric conditions. Four concentrations of suspended sediments (0 g/L, 1 g/L, 2 g/L, and 4 g/L) were used in a mixture with different grain sizes at 4 Bar for 96 h. Functional (filtration rate-FR) and biochemical endpoints (catalase-CAT, glutathione s-transferase-GST, and lipid peroxidation-LPO) were analyzed in the gonads, digestive gland, and gills of S. solida after a 96-h exposure at 4 Bar (the natural limit of the species vertical distribution). The FR showed a decreasing trend with the increasing sediment concentrations (significant effects at 2 and 4 g/L). Additionally, significant changes were observed for some of the tested oxidative stress biomarkers, which were concentration and tissue-dependent, i.e., CAT activity was significantly elevated in gills (1 g/L treatment), and GST was decreased in digestive gland (1 g/L treatment). Overall, the results show that suspended sediments, at 2 and 4 g/L, have negative functional impacts in the bivalve S. solida providing additional insights to improve hazard assessment of deep-sea mining. These findings represent a step forward to ensure the mitigation of the potential negative effects of deep-sea resource exploitation.

Benthic ostracods (Crustacea) from the Vitória-Trindade Chain, South Atlantic Ocean, with the description of five new species.

This work is the second part of the analysis of ostracods from the Vitória-Trindade Chain ̶ consisting of four seamounts and Trindade Island-which resulted in the recording of 28 species belonging to 14 genera and eight families. Five new species of Cytherellidae, Bairdiidae, Bythocytheridae, and Xestoleberididae are described in this paper, as follows: Keijcyoidea oceanica sp. nov., Bairdoppilata vitoriensis sp. nov., Vandenboldina kyryia sp. nov., Xestoleberis acuminata sp. nov. and Xestoleberis caperata sp. nov.

Beyond the TPP+ "gold standard": a new generation mitochondrial delivery vector based on extended PN frameworks.

Mitochondrial targeting represents an attractive strategy for treating metabolic, degenerative and hyperproliferative diseases, since this organelle plays key roles in essential cellular functions. Triphenylphosphonium (TPP+) moieties - the current "gold standard" - have been widely used as mitochondrial targeting vectors for a wide range of molecular cargo. Recently, further optimisation of the TPP+ platform drew considerable interest as a way to enhance mitochondrial therapies. However, although the modification of this system appears promising, the core structure of the TPP+ moiety remains largely unchanged. Thus, this study explored the use of aminophosphonium (PN+) and phosphazenylphosphonium (PPN+) main group frameworks as novel mitochondrial delivery vectors. The PPN+ moiety was found to be a highly promising platform for this purpose, owing to its unique electronic properties and high lipophilicity. This has been demonstrated by the high mitochondrial accumulation of a PPN+-conjugated fluorophore relative to its TPP+-conjugated counterpart, and has been further supported by density functional theory and molecular dynamics calculations, highlighting the PPN+ moiety's unusual electronic properties. These results demonstrate the potential of novel phosphorus-nitrogen based frameworks as highly effective mitochondrial delivery vectors over traditional TPP+ vectors.

Predicting hospital emergency department visits accurately: A systematic review.

OBJECTIVES: The emergency department (ED) is a very important healthcare entrance point, known for its challenging organisation and management due to demand unpredictability. An accurate forecast system of ED visits is crucial to the implementation of better management strategies that optimise resources utilization, reduce costs and improve public confidence. The aim of this review is to investigate the different factors that affect the ED visits forecasting outcomes, in particular the predictive variables and type of models applied. METHODS: A systematic search was conducted in PubMed, Web of Science and Scopus. The review methodology followed the PRISMA statement guidelines. RESULTS: Seven studies were selected, all exploring predictive models to forecast ED daily visits for general care. MAPE and RMAE were used to measure models' accuracy. All models displayed good accuracy, with errors below 10%. CONCLUSIONS: Model selection and accuracy was found to be particularly sensitive to the ED dimension. While ARIMA-based and other linear models have good performance for short-time forecast, some machine learning methods proved to be more stable when forecasting multiple horizons. The inclusion of exogenous variables was found to be advantageous only in bigger EDs.

Different Enzyme Conformations Induce Different Mechanistic Traits in HIV-1 Protease.

The influence of the dynamical flexibility of enzymes on reaction mechanisms is a cornerstone in biological sciences. In this study, we aim to 1) study the convergence of the activation free energy by using the first step of the reaction catalysed by HIV-1 protease as a case study, and 2) provide further evidence for a mechanistic divergence in this enzyme, as two different reaction pathways were seen to contribute to this step. We used quantum mechanics/molecular mechanics molecular dynamics simulations, on four different initial conformations that led to different barriers in a previous study. Despite the sampling, the four activation free energies still spanned a range of 5.0 kcal ⋅ mol-1 . Furthermore, the new simulations did confirm the occurrence of an unusual mechanistic divergence, with two different mechanistic pathways displaying equivalent barriers. An active-site water molecule is proposed to influence the mechanistic pathway.

Transmembrane Protease Serine 2 Proteolytic Cleavage of the SARS-CoV-2 Spike Protein: A Mechanistic Quantum Mechanics/Molecular Mechanics Study to Inspire the Design of New Drugs To Fight the COVID-19 Pandemic.

Despite the development of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, there is an urgent need for efficient drugs to treat infected patients. An attractive drug target is the human transmembrane protease serine 2 (TMPRSS2) because of its vital role in the viral infection mechanism of SARS-CoV-2 by activation of the virus spike protein (S protein). Having in mind that the information derived from quantum mechanics/molecular mechanics (QM/MM) studies could be an important tool in the design of transition-state (TS) analogue inhibitors, we resorted to adiabatic QM/MM calculations to determine the mechanism of the first step (acylation) of proteolytic cleavage of the S protein with atomistic details. Acylation occurred in two stages: (i) proton transfer from Ser441 to His296 concerted with the nucleophilic attack of Ser441 to the substrate's P1-Arg and (ii) proton transfer from His296 to the P1'-Ser residue concerted with the cleavage of the ArgP1-SerP1' peptide bond, with a Gibbs activation energy of 17.1 and 15.8 kcal mol-1, relative to the reactant. An oxyanion hole composed of two hydrogen bonds stabilized the rate-limiting TS by 8 kcal mol-1. An analysis of the TMPRSS2 interactions with the high-energy, short-lived tetrahedral intermediate highlighted the limitations of current clinical inhibitors and pointed out specific ways to develop higher-affinity TS analogue inhibitors. The results support the development of more efficient drugs against SARS-CoV-2 using a human target, free from resistance development.

Role of 5-HT2A receptors in the effects of ayahuasca on ethanol self-administration using a two-bottle choice paradigm in male mice.

RATIONALE: Ayahuasca has been proposed as a potential treatment of alcohol (ethanol) use disorder (AUD). The serotonin 5-HT2A receptor agonist N,N-dimethyltryptamine (DMT) is the main psychoactive component of ayahuasca, suggesting that its therapeutic effects may be mediated by 5-HT2A receptors. OBJECTIVES: The aim of the present study was to investigate the effects of ayahuasca on the expression of ethanol self-administration using a two-bottle choice procedure and the role of 5-HT2A receptors in those effects. METHODS: Male mice had intermittent access to ethanol (10% v/v) in a two-bottle choice procedure for 30 days. Animals were then submitted to 3 treatment phases, each followed by ethanol re-exposure tests. During the treatment phase, every 3 days, animals received i.p. injections of either vehicle or the 5-HT2A receptor antagonist M100907 (M100, 1 mg/kg) followed by an i.g. (gavage) administration of vehicle or ayahuasca (100 mg/kg) and were exposed to the self-administration apparatus with no ethanol availability. During re-exposure tests, animals were submitted to the same conditions as during acquisition, with no treatments prior to those sessions. RESULTS: Treatment with ayahuasca blocked the expression of ethanol self-administration, decreasing ethanol intake and preference during re-exposure tests. Pretreatment with M100 blocked the effects of ayahuasca on ethanol drinking without significantly attenuating ethanol self-administration. CONCLUSIONS: Treatment with ayahuasca during alcohol abstinence blocked the expression of alcohol self-administration in mice, and 5-HT2A receptor activation is critical for those effects to emerge. Our findings support a potential for ayahuasca and other 5-HT2A receptor agonists as adjunctive pharmacotherapies for the treatment of AUD.

Exploring the permeation of fluoroquinolone metalloantibiotics across outer membrane porins by combining molecular dynamics simulations and a porin-mimetic in vitro model.

The misuse and overuse of fluoroquinolones in recent years have triggered alarming levels of resistance to these antibiotics. Porin channels are crucial for the permeation of fluoroquinolones across the outer membrane of Gram-negative bacteria and modifications in porin expression are an important mechanism of bacterial resistance. One possible strategy to overcome this problem is the development of ternary copper complexes with fluoroquinolones. Compared to fluoroquinolones, these metalloantibiotics present a larger partition to the lipid bilayer and a more favorable permeation, by passive diffusion, across bacteriomimetic phospholipid-based model membranes. To rule out the porin-dependent pathway for the metalloantibiotics, we explored the permeation through OmpF (one of the most abundant porins present in the outer membrane of Gram-negative bacteria) using a multi-component approach. X-ray studies of OmpF porin crystals soaked with a ciprofloxacin ternary copper complex did not show a well-defined binding site for the compound. Molecular dynamics simulations showed that the translocation of the metalloantibiotic through this porin is less favorable than that of free fluoroquinolone, as it presented a much larger free energy barrier to cross the narrow constriction region of the pore. Lastly, permeability studies of different fluoroquinolones and their respective copper complexes using a porin-mimetic in vitro model corroborated the lower rate of permeation for the metalloantibiotics relative to the free antibiotics. Our results support a porin-independent mechanism for the influx of the metalloantibiotics into the bacterial cell. This finding brings additional support to the potential application of these metalloantibiotics in the fight against resistant infections and as an alternative to fluoroquinolones.

Ostracods (Crustacea: Ostracoda) of the Vitoria-Trindade Chain, Southwestern Atlantic.

The current work is part of a taxonomic study on ostracods from Trindade Island and four seamount summits of the Vitoria-Trindade Chain. Twenty-six species belonging to nine families and 17 genera were identified. Five species are described as new, as follows: two Cytheruridae (Hemicytherura trindadensis sp. nov., Semicytherura parva sp. nov.) and three Loxoconchidae (Loxocorniculum micropapillosum sp. nov., Phlyctocythere christophei sp. nov., Phlyctocythere apua sp. nov.). The other taxa are being studied in an ongoing survey.

Dynamics of growth differentiation factor 15 in acute heart failure.

AIMS: Risk stratification in acute heart failure (HF) patients can help to decide therapies and time for discharge. The potential of growth differentiation factor 15 (GDF-15) in HF has been previously shown. We aimed to study the importance of GDF-15-level variations in acute HF patients. METHODS AND RESULTS: We retrospectively evaluated a cohort of patients hospitalized due to acute HF. GDF-15 was measured both at admission and on the discharge day. Patients were followed-up during a 3 year period. The endpoint under analysis was all-cause mortality. GDF-15 variation is equal to [(admission GDF-15 - discharge GDF-15)∕admission GDF-15] × 100. Variation was categorized in levels of increase or decrease of GDF-15. Patients were cross-classified according to admission and discharge GDF-15 cut-off points. A Cox regression analysis was used to assess the prognostic impact of GDF-15 variation and the impact of both admission and discharge GDF-15 according to the cross-classification. We studied a group of 249 patients with high co-morbidity burden. Eighty-one patients died at 1 year and 147 within 3 years. There was a modest decrease in GDF-15 during hospitalization from a median value of 4087 to 3671 ng/mL (P = 0.02). No association existed between GDF-15 variation and mortality. In multivariate analysis, patients with admission GDF-15 ≥ 3500 ng/mL and discharge GDF-15 ≥ 3000 ng/mL had a significantly higher 1 year death risk when compared with the remaining-hazard ratio = 2.59 (95% confidence interval: 1.41-4.76)-and a 3 year 1.76 (95% confidence interval: 1.08-2.87) higher death risk compared with those with both values below the cut-off. CONCLUSIONS: Growth differentiation factor 15 decreased during an acute HF hospitalization, but its variation had no prognostic implications. The knowledge of both admission and discharge GDF-15 added meaningful information to patients' risk stratification.