Large Libraries of Structurally Diverse Macrocycles Suitable for Membrane Permeation.

Macrocycles offer an attractive format for drug development due to their good binding properties and potential to cross cell membranes. To efficiently identify macrocyclic ligands for new targets, methods for the synthesis and screening of large combinatorial libraries of small cyclic peptides were developed, many of them using thiol groups for efficient peptide macrocyclization. However, a weakness of these libraries is that invariant thiol-containing building blocks such as cysteine are used, resulting in a region that does not contribute to library diversity but increases molecule size. Herein, we synthesized a series of structurally diverse thiol-containing elements and used them for the combinatorial synthesis of a 2,688-member library of small, structurally diverse peptidic macrocycles with unprecedented skeletal complexity. We then used this library to discover potent thrombin and plasma kallikrein inhibitors, some also demonstrating favorable membrane permeability. X-ray structure analysis of macrocycle-target complexes showed that the size and shape of the newly developed thiol elements are key for binding. The strategy and library format presented in this work significantly enhance structural diversity by allowing combinatorial modifications to a previously invariant region of peptide macrocycles, which may be broadly applied in the development of membrane permeable therapeutics.

Respective roles of non-pharmaceutical interventions in bronchiolitis outbreaks: an interrupted time-series analysis based on a multinational surveillance system.

BACKGROUND: Bronchiolitis is a major source of morbimortality among young children worldwide. Non-pharmaceutical interventions (NPIs) implemented to reduce the spread of severe acute respiratory syndrome coronavirus 2 may have had an important impact on bronchiolitis outbreaks, as well as major societal consequences. Discriminating between their respective impacts would help define optimal public health strategies against bronchiolitis. We aimed to assess the respective impact of each NPI on bronchiolitis outbreaks in 14 European countries. METHODS: We conducted a quasi-experimental interrupted time-series analysis based on a multicentre international study. All children diagnosed with bronchiolitis presenting to the paediatric emergency department of one of 27 centres from January 2018 to March 2021 were included. We assessed the association between each NPI and change in the bronchiolitis trend over time by seasonally adjusted multivariable quasi-Poisson regression modelling. RESULTS: In total, 42 916 children were included. We observed an overall cumulative 78% (95% CI -100- -54%; p<0.0001) reduction in bronchiolitis cases following NPI implementation. The decrease varied between countries from -97% (95% CI -100- -47%; p=0.0005) to -36% (95% CI -79-7%; p=0.105). Full lockdown (incidence rate ratio (IRR) 0.21 (95% CI 0.14-0.30); p<0.001), secondary school closure (IRR 0.33 (95% CI 0.20-0.52); p<0.0001), wearing a mask indoors (IRR 0.49 (95% CI 0.25-0.94); p=0.034) and teleworking (IRR 0.55 (95% CI 0.31-0.97); p=0.038) were independently associated with reducing bronchiolitis. CONCLUSIONS: Several NPIs were associated with a reduction of bronchiolitis outbreaks, including full lockdown, school closure, teleworking and facial masking. Some of these public health interventions may be considered to further reduce the global burden of bronchiolitis.

Influence of epidemics and pandemics on paediatric ED use: a systematic review.

OBJECTIVE: To assess the impact of epidemics and pandemics on the utilisation of paediatric emergency care services to provide health policy advice. SETTING: Systematic review. DESIGN: Searches were conducted of Medline, EMBASE, CINAHL, Scopus, Web of Science and the Cochrane Library for studies that reported on changes in paediatric emergency care utilisation during epidemics (as defined by the WHO). PATIENTS: Children under 18 years. INTERVENTIONS: National Institutes of Health quality assessment tool for observational cohort and cross-sectional studies was used. MAIN OUTCOME MEASURES: Changes in paediatric emergency care utilisation. RESULTS: 131 articles were included within this review, 80% of which assessed the impact of COVID-19. Studies analysing COVID-19, SARS, Middle East respiratory syndrome (MERS) and Ebola found a reduction in paediatric emergency department (PED) visits, whereas studies reporting on H1N1, chikungunya virus and Escherichia coli outbreaks found an increase in PED visits. For COVID-19, there was a reduction of 63.86% (95% CI 60.40% to 67.31%) with a range of -16.5% to -89.4%. Synthesis of results suggests that the fear of the epidemic disease, from either contracting it or its potential adverse clinical outcomes, resulted in reductions and increases in PED utilisation, respectively. CONCLUSIONS: The scale and direction of effect of PED use depend on both the epidemic disease, the public health measures enforced and how these influence decision-making. Policy makers must be aware how fear of virus among the general public may influence their response to public health advice. There is large inequity in reporting of epidemic impact on PED use which needs to be addressed. TRIAL REGISTRATION NUMBER: CRD42021242808.

Presentations of children to emergency departments across Europe and the COVID-19 pandemic: A multinational observational study.

BACKGROUND: During the initial phase of the Coronavirus Disease 2019 (COVID-19) pandemic, reduced numbers of acutely ill or injured children presented to emergency departments (EDs). Concerns were raised about the potential for delayed and more severe presentations and an increase in diagnoses such as diabetic ketoacidosis and mental health issues. This multinational observational study aimed to study the number of children presenting to EDs across Europe during the early COVID-19 pandemic and factors influencing this and to investigate changes in severity of illness and diagnoses. METHODS AND FINDINGS: Routine health data were extracted retrospectively from electronic patient records of children aged 18 years and under, presenting to 38 EDs in 16 European countries for the period January 2018 to May 2020, using predefined and standardized data domains. Observed and predicted numbers of ED attendances were calculated for the period February 2020 to May 2020. Poisson models and incidence rate ratios (IRRs), using predicted counts for each site as offset to adjust for case-mix differences, were used to compare age groups, diagnoses, and outcomes. Reductions in pediatric ED attendances, hospital admissions, and high triage urgencies were seen in all participating sites. ED attendances were relatively higher in countries with lower SARS-CoV-2 prevalence (IRR 2.26, 95% CI 1.90 to 2.70, p < 0.001) and in children aged <12 months (12 to <24 months IRR 0.86, 95% CI 0.84 to 0.89; 2 to <5 years IRR 0.80, 95% CI 0.78 to 0.82; 5 to <12 years IRR 0.68, 95% CI 0.67 to 0.70; 12 to 18 years IRR 0.72, 95% CI 0.70 to 0.74; versus age <12 months as reference group, p < 0.001). The lowering of pediatric intensive care admissions was not as great as that of general admissions (IRR 1.30, 95% CI 1.16 to 1.45, p < 0.001). Lower triage urgencies were reduced more than higher triage urgencies (urgent triage IRR 1.10, 95% CI 1.08 to 1.12; emergent and very urgent triage IRR 1.53, 95% CI 1.49 to 1.57; versus nonurgent triage category, p < 0.001). Reductions were highest and sustained throughout the study period for children with communicable infectious diseases. The main limitation was the retrospective nature of the study, using routine clinical data from a wide range of European hospitals and health systems. CONCLUSIONS: Reductions in ED attendances were seen across Europe during the first COVID-19 lockdown period. More severely ill children continued to attend hospital more frequently compared to those with minor injuries and illnesses, although absolute numbers fell. TRIAL REGISTRATION: ISRCTN91495258 https://www.isrctn.com/ISRCTN91495258.

Solid-phase peptide synthesis on disulfide-linker resin followed by reductive release affords pure thiol-functionalized peptides.

Thiol groups are suitable handles for site-selectively modifying, immobilizing or cyclizing individual peptides or entire peptide libraries. A limiting step in producing the thiol-functionalized peptides is the chromatographic purification, which is particularly laborious and costly if many peptides or even large libraries are to be produced. Herein, we present a strategy in which thiol-functionalized peptides are obtained in >90% purity and free of reducing agent, without a single chromatographic purification step. In brief, peptides are synthesized on a solid support linked via a disulfide bridge, the side-chain protecting groups are eliminated and washed away while the peptides remain on resin, and rather pure peptides are released from the solid support by reductive cleavage of the disulfide linker. Application of a volatile reducing agent, 1,4-butanedithiol (BDT), enabled removal of the agent by evaporation. We demonstrate that the approach is suited for the parallel synthesis of many peptides and that peptides containing a second thiol group can directly be cyclized by bis-electrophilic alkylating reagents for producing libraries of cyclic peptides.

Synthesis and direct assay of large macrocycle diversities by combinatorial late-stage modification at picomole scale.

Macrocycles have excellent potential as therapeutics due to their ability to bind challenging targets. However, generating macrocycles against new targets is hindered by a lack of large macrocycle libraries for high-throughput screening. To overcome this, we herein established a combinatorial approach by tethering a myriad of chemical fragments to peripheral groups of structurally diverse macrocyclic scaffolds in a combinatorial fashion, all at a picomole scale in nanoliter volumes using acoustic droplet ejection technology. In a proof-of-concept, we generate a target-tailored library of 19,968 macrocycles by conjugating 104 carboxylic-acid fragments to 192 macrocyclic scaffolds. The high reaction efficiency and small number of side products of the acylation reactions allowed direct assay without purification and thus a large throughput. In screens, we identify nanomolar inhibitors against thrombin (Ki = 44 ± 1 nM) and the MDM2:p53 protein-protein interaction (Kd MDM2 = 43 ± 18 nM). The increased efficiency of macrocycle synthesis and screening and general applicability of this approach unlocks possibilities for generating leads against any protein target.

Update on the Coordinated Efforts of Looking After the Health Care Needs of Children and Young People Fleeing the Conflict Zone of Ukraine Presenting to European Emergency Departments-A Joint Statement of the European Society for Emergency Paediatrics and the European Academy of Paediatrics.

This joint statement by the European Society for Emergency Paediatrics and European Academy of Paediatrics aims to highlight recommendations for dealing with refugee children and young people fleeing the Ukrainian war when presenting to emergency departments (EDs) across Europe. Children and young people might present, sometimes unaccompanied, with either ongoing complex health needs or illnesses, mental health issues, and injuries related to the war itself and the flight from it. Obstacles to providing urgent and emergency care include lack of clinical guidelines, language barriers, and lack of insight in previous medical history. Children with complex health needs are at high risk for complications and their continued access to specialist healthcare should be prioritized in resettlements programs. Ukraine has one of the lowest vaccination coverages in the Europe, and outbreaks of cholera, measles, diphtheria, poliomyelitis, and COVID-19 should be anticipated. In Ukraine, rates of multidrug resistant tuberculosis are high, making screening for this important. Urgent and emergency care facilities should also prepare for dealing with children with war-related injuries and mental health issues. Ukrainian refugee children and young people should be included in local educational systems and social activities at the earliest opportunity.

Discovery of a Non-Nucleoside SETD2 Methyltransferase Inhibitor against Acute Myeloid Leukemia.

Histone methyltransferases (HMTs) have attracted considerable attention as potential targets for pharmaceutical intervention in various malignant diseases. These enzymes are known for introducing methyl marks at specific locations of histone proteins, creating a complex system that regulates epigenetic control of gene expression and cell differentiation. Here, we describe the identification of first-generation cell-permeable non-nucleoside type inhibitors of SETD2, the only mammalian HMT that is able to tri-methylate the K36 residue of histone H3. By generating the epigenetic mark H3K36me3, SETD2 is involved in the progression of acute myeloid leukemia. We developed a structure-based virtual screening protocol that was first validated in retrospective studies. Next, prospective screening was performed on a large library of commercially available compounds. Experimental validation of 22 virtual hits led to the discovery of three compounds that showed dose-dependent inhibition of the enzymatic activity of SETD2. Compound C13 effectively blocked the proliferation of two acute myeloid leukemia (AML) cell lines with MLL rearrangements and led to decreased H3K36me3 levels, prioritizing this chemotype as a viable chemical starting point for drug discovery projects.

Responses of paediatric emergency departments to the first wave of the COVID-19 pandemic in Europe: a cross-sectional survey study.

OBJECTIVE: Understanding how paediatric emergency departments (PEDs) across Europe adapted their healthcare pathways in response to COVID-19 will help guide responses to ongoing waves of COVID-19 and potential future pandemics. This study aimed to evaluate service reconfiguration across European PEDs during the initial COVID-19 wave. DESIGN: This cross-sectional survey included 39 PEDs in 17 countries. The online questionnaire captured (1) study site characteristics, (2) departmental changes and (3) pathways for children with acute illness pre and during the first wave of COVID-19 pandemic (January-May 2020). Number of changes to health services, as a percentage of total possible changes encompassed by the survey, was compared with peak national SARS-CoV-2 incidence rates, and for both mixed and standalone paediatric centres. RESULTS: Overall, 97% (n=38) of centres remained open as usual during the pandemic. The capacity of 18 out of 28 (68%) short-stay units decreased; in contrast, 2 units (7%) increased their capacity. In 12 (31%) PEDs, they reported acting as receiving centres for diverted children during the pandemic.There was minimal change to the availability of paediatric consultant telephone advice services, consultant supervision of juniors or presence of responsible specialists within the PEDs.There was no relationship between percentage of possible change at each site and the peak national SARS-CoV-2 incidence rate. Mixed paediatric and adult hospitals made 8% of possible changes and standalone paediatric centres made 6% of possible changes (p=0.086). CONCLUSION: Overall, there was limited change to the organisation or delivery of services across surveyed PEDs during the first wave of the COVID-19 pandemic.

Variability in the management and imaging use in paediatric minor head trauma in European emergency departments. A Research in European Pediatric Emergency Medicine study.

OBJECTIVE: The objective of the study was to assess the variability in the management of paediatric MHT in European emergency departments (EDs). METHODS: This was a multicentre retrospective study of children ≤18 years old with minor head trauma (MHT) (Glasgow Coma Scale ≥14) who presented to 15 European EDs between 1 January 2013 and 31 December 31. Data on clinical characteristics, imaging tests, and disposition of included patients were collected at each hospital over a 3-year period. RESULTS: We included 11 212 patients. Skull radiography was performed in 3416 (30.5%) patients, range 0.4-92.3%. A computed tomography (CT) was obtained in 696 (6.2%) patients, range 1.6-42.8%. The rate of admission varied from 0 to 48.2%. CONCLUSION: We found great variability in terms of the type of imaging and rate of CT scan obtained. Our study suggests opportunity for improvement in the area of paediatric head injury and the need for targeted individualised ED interventions to improve management of MHT.

Promoting Breastfeeding and Interaction of Pediatric Associations With Providers of Nutritional Products.

Pediatric associations have been urged not to interact with and not to accept support from commercial providers of breast milk substitutes (BMSs), based on the assumption that such interaction would lead to diminished promotion and support of breastfeeding. The leadership of seven European pediatric learned societies reviewed the issue and share their position and policy conclusions here. We consider breastfeeding as the best way of infant feeding and strongly encourage its active promotion, protection, and support. We support the World Health Organization (WHO) Code of Marketing of BMSs. Infant formula and follow-on formula for older infants should not be advertised to families or the public, to avoid undermining breastfeeding. With consistently restricted marketing of BMSs, families need counseling on infant feeding choices by well-informed pediatricians. Current and trustworthy information is shared through congresses and other medical education directed and supervised by independent pediatric organizations or public bodies. Financial support from commercial organizations for congresses, educational, and scientific activities of pediatric organizations is an acceptable option if scientific, ethical, societal, and legal standards are followed; any influence of commercial organizations on the program is excluded, and transparency is ensured. Public-private research collaborations for improving and evaluating pharmaceuticals, vaccines, medical devices, dietetic products, and other products and services for children are actively encouraged, provided they are guided by the goal of enhancing child health and are performed following established high standards. We support increasing investment of public funding for research aiming at promoting child health, as well as for medical education.

Evaluation of 100 laparoscopic varicocele operations with preservation of testicular artery and ligation of collateral vein in children and adolescents.

OBJECTIVES: To introduce a useful technique for identifying any collateral veins during laparoscopic varicocele operation and to evaluate our long-term results with this technique after 100 cases. METHODS: A new method was used to detect an incidental collateral vein. During surgery the patient was placed in anti-Trendelenburg position after introducing laparoscopic instruments until the dilated scrotal varicose filled up with blood. The main spermatic vein was then grasped atraumatically and the blood was pressed out manually from the scrotum. During this manoeuvre any existing collateral vein/veins became dilated and could be easily identified. The dilated spermatic vein and also any collateral vessel were first prepared then clipped. RESULTS: Out of the 100 patients, collateral veins were detected and ligated in 19 cases. In 15 cases a single collateral, in 4 cases two collaterals, and in the remaining 81 children no collateral veins were found. The testicular artery was identified in all operations as a pulsatile vessel. At a mean of 24 months (range 6-60 months) follow-up recurrence occurred in one patient and in five children hydrocele developed postoperatively. Testicular atrophy and severe intra- or postoperative complication did not occur in any patient of this series. CONCLUSION: The identification of incidental collateral vein by this method and preservation of the testicular artery resulted in a very good success rate in children and adolescents treated by laparoscopic varicocele operation.