Evidence for low nanocompaction of heterochromatin in living embryonic stem cells.

Despite advances in the identification of chromatin regulators and genome interactions, the principles of higher-order chromatin structure have remained elusive. Here, we applied FLIM-FRET microscopy to analyse, in living cells, the spatial organisation of nanometre range proximity between nucleosomes, which we called "nanocompaction." Both in naive embryonic stem cells (ESCs) and in ESC-derived epiblast-like cells (EpiLCs), we find that, contrary to expectations, constitutive heterochromatin is much less compacted than bulk chromatin. The opposite was observed in fixed cells. HP1α knockdown increased nanocompaction in living ESCs, but this was overridden by loss of HP1ß, indicating the existence of a dynamic HP1-dependent low compaction state in pluripotent cells. Depletion of H4K20me2/3 abrogated nanocompaction, while increased H4K20me3 levels accompanied the nuclear reorganisation during EpiLCs induction. Finally, the knockout of the nuclear cellular-proliferation marker Ki-67 strongly reduced both interphase and mitotic heterochromatin nanocompaction in ESCs. Our data indicate that, contrary to prevailing models, heterochromatin is not highly compacted at the nanoscale but resides in a dynamic low nanocompaction state that depends on H4K20me2/3, the balance between HP1 isoforms, and Ki-67.

The multifunction Coxiella effector Vice stimulates macropinocytosis and interferes with the ESCRT machinery.

Intracellular bacterial pathogens divert multiple cellular pathways to establish their niche and persist inside their host. Coxiella burnetii, the causative agent of Q fever, secretes bacterial effector proteins via its Type 4 secretion system to generate a Coxiella-containing vacuole (CCV). Manipulation of lipid and protein trafficking by these effectors is essential for bacterial replication and virulence. Here, we have characterized the lipid composition of CCVs and found that the effector Vice interacts with phosphoinositides and membranes enriched in phosphatidylserine and lysobisphosphatidic acid. Remarkably, eukaryotic cells ectopically expressing Vice present compartments that resemble early CCVs in both morphology and composition. We found that the biogenesis of these compartments relies on the double function of Vice. The effector protein initially localizes at the plasma membrane of eukaryotic cells where it triggers the internalization of large vacuoles by macropinocytosis. Then, Vice stabilizes these compartments by perturbing the ESCRT machinery. Collectively, our results reveal that Vice is an essential C. burnetii effector protein capable of hijacking two major cellular pathways to shape the bacterial replicative niche.

Efficacy of infliximab after loss of response of/intolerance to adalimumab in pediatric Crohn's disease: A retrospective multicenter cohort study of the "GETAID pédiatrique".

BACKGROUND: Infliximab (IFX) and adalimumab (ADA) are recommended for induction and maintenance of remission in pediatric Crohn's disease (CD). ADA is now often used in first line due to its efficacy and tolerability, but a loss of response (LOR) can occur over time. The aim was to assess the efficacy of IFX as second line therapy after LOR or intolerance to ADA in pediatric CD patients at 1 year. METHODS: We conducted a retrospective and multicenter study in France among the "GETAID pédiatrique" centers between April 2019 and April 2022. CD patients under 18 years old and treated with IFX after ADA failure or intolerance were included. We collected anthropometric, clinical, and biological data at baseline (start of IFX), at 6 and 12 months. Clinical remission was defined by a Weighted Pediatric CD Activity Index (wPCDAI) score less than 12.5 points. RESULTS: Of the 32 patients included in our study, 27 (84.4%) were still on IFX at 12 months of the switch. Among them, 13 had discontinued ADA because of a LOR, 12 for insufficient response and 2 due to primary nonresponse. At M12, 22 patients were in corticosteroid free clinical remission (68.7%). Under IFX, the wPCDAI decreased over time (47.5 ± 24.1, 16.6 ± 21.2 and 9.7 ± 19.0 at M0, M6 and M12 respectively). The only factor associated with clinical remission at 12 months was absence of perianal disease at the end of the IFX induction. CONCLUSIONS: IFX is effective in maintaining remission at 1 year in pediatric CD patients experiencing a LOR or intolerance with ADA, and IFX could be an interesting therapeutic choice instead of other biologics in this situation.

Natural History of Anal Ulcerations in Pediatric-Onset Crohn's Disease: Long-Term Follow-Up of a Population-Based Study.

INTRODUCTION: Anal ulcerations are frequently observed in Crohn's disease (CD). However, their natural history remains poorly known, especially in pediatric-onset CD. METHODS: All patients with a diagnosis of CD before the age of 17 years between 1988 and 2011 within the population-based registry EPIMAD were followed retrospectively until 2013. At diagnosis and during follow-up, the clinical and therapeutic features of perianal disease were recorded. An adjusted time-dependent Cox model was used to evaluate the risk of evolution of anal ulcerations toward suppurative lesions. RESULTS: Among the 1,005 included patients (females, 450 [44.8%]; median age at diagnosis 14.4 years [interquartile range 12.0-16.1]), 257 (25.6%) had an anal ulceration at diagnosis. Cumulative incidence of anal ulceration at 5 and 10 years from diagnosis was 38.4% (95% confidence interval [CI] 35.2-41.4) and 44.0% (95% CI 40.5-47.2), respectively. In multivariable analysis, the presence of extraintestinal manifestations (hazard ratio [HR] 1.46, 95% CI 1.19-1.80, P = 0.0003) and upper digestive location (HR 1.51, 95% CI 1.23-1.86, P < 0.0001) at diagnosis were associated with the occurrence of anal ulceration. Conversely, ileal location (L1) was associated with a lower risk of anal ulceration (L2 vs L1 HR 1.51, 95% CI 1.11-2.06, P = 0.0087; L3 vs L1 HR 1.42, 95% CI 1.08-1.85, P = 0.0116). The risk of fistulizing perianal CD (pCD) was doubled in patients with a history of anal ulceration (HR 2.00, 95% CI 1.45-2.74, P < 0.0001). Among the 352 patients with at least 1 episode of anal ulceration without history of fistulizing pCD, 82 (23.3%) developed fistulizing pCD after a median follow-up of 5.7 years (interquartile range 2.8-10.6). In these patients with anal ulceration, the diagnostic period (pre vs biologic era), exposure to immunosuppressants, and/or anti-tumor necrosis factor did not influence the risk of secondary anoperineal suppuration. DISCUSSION: Anal ulceration is frequent in pediatric-onset CD, with nearly half of patients presenting with at least 1 episode after 10 years of evolution. Fistulizing pCD is twice as frequent in patients with present or past anal ulceration.

New Therapeutic Strategies Are Associated With a Significant Decrease in Colectomy Rate in Pediatric Ulcerative Colitis.

INTRODUCTION: We evaluated the impact of immunosuppressants (IS) and antitumor necrosis factor (TNF) introduction on long-term outcomes of ulcerative colitis (UC) in a large population-based pediatric-onset cohort. METHODS: All patients included in the EPIMAD registry with a diagnosis of UC made before the age of 17 years between 1988 and 2011 were followed up retrospectively until 2013. Medication exposure and disease outcomes were compared between 3 diagnostic periods: 1988 to 1993 (period [P] 1; pre-IS era), 1994 to 2000 (P2; pre-anti-TNF era), and 2001 to 2011 (P3; anti-TNF era). RESULTS: A total of 337 patients (female, 57%) diagnosed with UC were followed up during a median duration of 7.2 years (interquartile range 3.8-13.0). The IS and anti-TNF exposure rates at 5 years increased over time from 7.8% (P1) to 63.8% (P3) and from 0% (P1) to 37.2% (P3), respectively. In parallel, the risk of colectomy at 5 years decreased significantly over time (P1, 17%; P2, 19%; and P3, 9%; P = 0.045, P -trend = 0.027) and between the pre-anti-TNF era (P1 + P2, 18%) and the anti-TNF era (P3, 9%) ( P = 0.013). The risk of disease extension at 5 years remained stable over time (P1, 36%, P2, 32%, and P3, 34%; P = 0.31, P -trend = 0.52) and between the pre-anti-TNF era (P1 + P2, 34%) and the anti-TNF era (P3, 34%) ( P = 0.92). The risk of flare-related hospitalization at 5 years significantly increased over time (P1, 16%; P2, 27%; P3, 42%; P = 0.0012, P -trend = 0.0006) and between the pre-anti-TNF era (P1 + P2, 23%) and the anti-TNF era (P3, 42%) ( P = 0.0004). DISCUSSION: In parallel with the increased use of IS and anti-TNF, an important decline in the risk of colectomy in pediatric-onset UC was observed at the population level.

Ustekinumab Use in Pediatric Inflammatory Bowel Disease: A French Multicenter Study From the Pediatric GETAID.

OBJECTIVES: Ustekinumab is known to be efficient in adult patients suffering from moderate to severe Crohn disease (CD) and ulcerative colitis (UC) resistant to anti-tumor necrosis factor-alpha (TNF-α). Here, we described the clinical course of treatment with ustekinumab in French pediatric inflammatory bowel disease (IBD) patients treated with ustekinumab. METHODS: This study includes all pediatric patients treated by ustekinumab injection for IBD (CD and UC), between January 2016 and December 2019. RESULTS: Fifty-three patients were enrolled, 15 males and 38 females. Forty-eight patients (90%) had a diagnosis of CD and 5 (9.4%) had UC. Sixty-five percent of CD patients presented an ileocolitis. Perineal disease was observed in 20 out of 48 CD patients (41.7%), among them 9 were treated surgically. All patients included were resistant to anti-TNF-α treatment. Fifty-one percent had presented side effects linked to anti-TNF-α, including psoriasis and anaphylactic reaction. The average Pediatric Crohn Disease Activity Index (PCDAI) at induction was 28.7 (5-85), 18.7 (0-75) at 3 months of treatment and 10 (0-35) at the last follow-up. The average Pediatric Ulcerative Colitis Activity Index at induction was 47 (25-65), 25 (15-40) at 3 months of treatment and 18.3 (0-35) at the last follow-up. No severe side effects were observed. CONCLUSION: In this retrospective, multicentral study, ustekinumab proved to be efficient in pediatric patients resistant to anti-TNF-α. PCDAI has been significantly improved in patients with severe disease, treated with ustekinumab.

New Therapeutic Strategies Have Changed the Natural History of Pediatric Crohn's Disease: A Two-Decade Population-Based Study.

BACKGROUND & AIMS: We evaluated the impact of immunosuppressants (IS) and anti-tumor necrosis factor (TNF) introduction on Crohn's disease (CD) long-term outcomes in a large population-based, pediatric-onset cohort. METHODS: All patients included in the EPIMAD registry with a diagnosis of CD occurring when they were younger than age 17 years and between 1988 and 2011 were followed up retrospectively until 2013. Three diagnostic periods were defined: 1988 to 1993 (period [P]1; pre-IS era), 1994 to 2000 (P2; pre-anti-TNF era), and 2001 to 2011 (P3; anti-TNF era). Medication exposure and disease outcomes were compared between the 3 diagnostic periods. RESULTS: A total of 1007 patients diagnosed with CD were followed up for a median duration of 8.8 years (interquartile range, 4.6-14.2 y). The IS and anti-TNF exposure rate at 5 years increased over time from 33.9% (in P1) to 76.5% (in P3) and from 0% (in P1) to 50.5% (in P3), respectively. In parallel, the risk for intestinal resection at 5 years decreased significantly over time (P1, 35%; P2, 31%; and P3, 22%; P = .0003, Ptrend < .0001), and between the pre-anti-TNF era (P1 + P2, 32%) and the anti-TNF era (P3, 22%) (P = .0007). The risk for progression from inflammatory to stricturing behavior decreased significantly over time (P1, 27%; P2, 28%; and P3, 20%; P = .11, Ptrend = .041) and between the pre-anti-TNF era (P1 + P2, 28%) and the anti-TNF era (P3, 20%) (P = .040). The risk for a CD flare-related hospitalization at 5 years remained stable over time (P1, 31%; P2, 31%; and P3, 29%; P = .76, Ptrend = .53). CONCLUSIONS: In parallel with the increased use of IS and anti-TNF, positive changes in the natural history of pediatric-onset CD were observed at the population level. A decreased risk of both intestinal resections and stricturing complications were observed during the anti-TNF era.

Proton Pump Inhibitor Use and Associated Infectious Complications in the PICU: Propensity Score Matching Analysis.

OBJECTIVES: We aimed to evaluate the association between proton pump inhibitor (PPI) exposure and nosocomial infection (NI) during PICU stay. DESIGN: Propensity score matched analysis of a single-center retrospective cohort from January 1, 2017, to December 31, 2018. SETTING: Tertiary medical and surgical PICU in France. PATIENTS: Patients younger than 18 years old, admitted to the PICU with a stay greater than 48 hours. INTERVENTION: Patients were retrospectively allocated into two groups and compared depending on whether they received a PPI or not. MEASUREMENTS AND MAIN RESULTS: Seven-hundred fifty-four patients were included of which 231 received a PPI (31%). PPIs were mostly used for stress ulcer prophylaxis (174/231; 75%), but upper gastrointestinal bleed risk factors were rarely present (18%). In the unadjusted analyses, the rate of NI was 8% in the PPI exposed group versus 2% in the nonexposed group. After propensity score matching ( n = 184 per group), we failed to identify an association between PPI exposure and greater odds of NI (adjusted odds ratio 2.9 [95% CI, 0.9-9.3]; p = 0.082). However, these data have not excluded the possibility that there is up to nine-fold greater odds of NI. CONCLUSIONS: This study highlights the prevalent use of PPIs in the PICU, and the potential association between PPIs and nine-fold greater odds of NI is not excluded.

Clinical Remission and Psychological Management are Major Issues for the Quality of Life in Pediatric Crohn Disease.

OBJECTIVES: Crohn disease (CD) can affect patient's quality of life (QOL) with physical, social, and psychological impacts. This study aimed to investigate the QOL of children with CD and its relationship with patient and disease characteristics. METHODS: Children ages from 10 to 17 years with diagnosed CD for more than 6 months were eligible to this cross-sectional study conducted in 35 French pediatric centers. QOL was assessed by the IMPACT-III questionnaire. Patient and disease characteristics were collected. RESULTS: A total of 218 children (42% of girls) were included at a median age of 14 years (interquartile range [IQR]: 13--16). Median duration of CD was 3.2 years (IQR: 1.7-5.1) and 63% of children were in clinical remission assessed by wPCDAI. Total IMPACT-III score was 62.8 (±11.0). The lowest score was in "emotional functioning" subdomain (mean: 42.8 ±â€Š11.2). Clinical remission was the main independent factor associated with QOL of children with CD (5.74 points higher compared with those "with active disease", 95% confidence interval [CI] 2.77--8.70, P < 0.001). Age of patient at the evaluation was found negatively correlated with QOL (-0.76 per year, 95% CI: -1.47 to -0.06, P = 0.009). Presence of psychological disorders was associated with a lower QOL (-9.6 points lower to those without, 95% CI: -13.34 to -5.86, P < 0.0001). Total IMPACT-III and its subdomains scores were not related to sex, disease duration, or treatments. CONCLUSIONS: These results not only confirm that clinical remission is a major issue for the QOL of patients, but also highlights the importance of psychological care.

A Data-Driven Space-Time-Parameter Reduced-Order Model with Manifold Learning for Coupled Problems: Application to Deformable Capsules Flowing in Microchannels.

An innovative data-driven model-order reduction technique is proposed to model dilute micrometric or nanometric suspensions of microcapsules, i.e., microdrops protected in a thin hyperelastic membrane, which are used in Healthcare as innovative drug vehicles. We consider a microcapsule flowing in a similar-size microfluidic channel and vary systematically the governing parameter, namely the capillary number, ratio of the viscous to elastic forces, and the confinement ratio, ratio of the capsule to tube size. The resulting space-time-parameter problem is solved using two global POD reduced bases, determined in the offline stage for the space and parameter variables, respectively. A suitable low-order spatial reduced basis is then computed in the online stage for any new parameter instance. The time evolution of the capsule dynamics is achieved by identifying the nonlinear low-order manifold of the reduced variables; for that, a point cloud of reduced data is computed and a diffuse approximation method is used. Numerical comparisons between the full-order fluid-structure interaction model and the reduced-order one confirm both accuracy and stability of the reduction technique over the whole admissible parameter domain. We believe that such an approach can be applied to a broad range of coupled problems especially involving quasistatic models of structural mechanics.

Identification of Parameters Influencing the Vascular Structure Displacement in Fusion Imaging during Endovascular Aneurysm Repair.

PURPOSE: To quantify the displacement of the vascular structures after insertion of stiff devices during endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm and to identify potential parameters influencing this displacement. MATERIALS AND METHODS: A total of 50 patients from a single center undergoing EVAR were prospectively enrolled between January 2016 and December 2017. Fusion imaging was employed using the EndoNaut (Therenva, Rennnes, France) station through a 3-dimensional (3D)/2-dimensional (2D) technology synchronizing the 3D computed tomography scan to the live intraoperative fluoroscopy. The accuracy of the fusion roadmap was evaluated before deployment by conventional digital subtraction angiogram on a single plane (with different C-arm incidences). RESULTS: The mean displacement error of the ostium of the lowest renal artery was 4.1 ± 2.4 mm (range, 0-11.7 mm), with a left/right displacement of 1.6 ± 1.7 mm (range, 0-6.9 mm) and a craniocaudal displacement of 3.5 ± 2.4 mm (range, 0-11.3 mm). The correction required for the ostium of the lower renal artery was mostly cranial and to the left. Multiple linear regression analysis revealed only the sharpest angle between the aneurysm neck and sac as the factor influencing the accuracy of fusion imaging. All other parameters did not show any correlation. CONCLUSIONS: This study identified the sources of fusion error after insertion of rigid material during EVAR. As the sharpest angulation between aneurysm neck and sac increases, the overall accuracy of the fusion might be affected.

Use of Numerical Simulation to Predict Iliac Complications During Placement of An Aortic Stent Graft.

BACKGROUND: During endovascular aneurysm repair (EVAR), complex iliac anatomy is a source of complications such as unintentional coverage of the hypogastric artery. The aim of our study was to evaluate ability to predict coverage of the hypogastric artery using a biomechanical model simulating arterial deformations caused by the delivery system. METHODS: The biomechanical model of deformation has been validated by many publications. The simulations were performed on 38 patients included retrospectively, for a total of 75 iliac arteries used for the study. On the basis of objective measurements, two groups were formed: one with "complex" iliac anatomy (n = 38 iliac arteries) and the other with "simple" iliac anatomy (n = 37 iliac arteries). The simulation enabled measurement of the lengths of the aorta and the iliac arteries once deformed by the device. Coverage of the hypogastric artery was predicted if the deformed renal/iliac bifurcation length (Lpre) was less than the length of the implanted device (Lstent-measured on the postoperative computed tomography [CT]) and nondeformed Lpre was greater than Lstent. RESULTS: Nine (12%) internal iliac arteries were covered unintentionally. Of the coverage attributed to perioperative deformations, 1 case (1.3%) occurred with simple anatomy and 6 (8.0%) with complex anatomy (P = 0.25). All cases of unintentional coverage were predicted by the simulation. The simulation predicted hypogastric coverage in 35 cases (46.7%). There were therefore 26 (34.6%) false positives. The simulation had a sensitivity of 100% and a specificity of 60.6%. On multivariate analysis, the factors significantly predictive of coverage were the iliac tortuosity index (P = 0.02) and the predicted margin between the termination of the graft limb and the origin of the hypogastric artery in nondeformed (P = 0.009) and deformed (P = 0.001) anatomy. CONCLUSIONS: Numerical simulation is a sensitive tool for predicting the risk of hypogastric coverage during EVAR and allows more precise preoperative sizing. Its specificity is liable to be improved by using a larger cohort.

Prevalence of Barrett Esophagus in Adolescents and Young Adults With Esophageal Atresia.

OBJECTIVE: To study the prevalence of Barrett esophagus (BE) (gastric and/or intestinal metaplasia) in adolescents treated for esophageal atresia (EA). SUMMARY OF BACKGROUND DATA: EA patients are at high risk of BE. METHODS: This multicenter prospective study included EA patients aged 15 to 19 years. All eligible patients were proposed an upper endoscopy with multistaged esophageal biopsies under general anesthesia. Histological suspicion of metaplasia was confirmed centrally. RESULTS: One hundred twenty patients [mean age, 16.5 years (±1.4)] were included; 70% had been treated for gastroesophageal reflux disease (GERD) during infancy. At evaluation, 8% were undernourished, 41% had received antireflux surgery, and 41% presented with GERD symptoms, although only 28% were receiving medical treatment. Esophagitis was found at endoscopy in 34% and confirmed at histology in 67%. BE was suspected after endoscopy in 37% and was confirmed by histology for 43% of patients (50 gastric and 1 intestinal metaplasia). No endoscopic or histological anomalies were found at the anastomosis site. BE was not significantly related to clinical symptoms. In multivariate analysis, BE was associated with EA without fistula (P = 0.03), previous multiple antireflux surgery (P = 0.04), esophageal dilation (P = 0.04), suspicion of BE at endoscopy (P < 0.001), and histological esophagitis (P = 0.02). CONCLUSIONS: Patients with EA are at high risk of persistent GERD and BE. The development of BE is related to GERD history. Long-term systematic follow-up of the esophageal mucosa including multistaged biopsies is required, even in asymptomatic patients. (NCT02495051).

About the usefulness of contact precautions for carriers of extended-spectrum beta-lactamase-producing Escherichia coli.

BACKGROUND: Extended-spectrum ß-lactamases producing Escherichia coli (ESBL-E) are increasingly identified in health care facilities. As previously done for the control of methicillin-resistant Staphylococcus aureus, many hospitals have established screening strategies for early identification of patients being carriers of ESBL producers in general and ESBL-E in particular, and have implemented contact precautions (CP) for infected and colonized patients. METHODS: The incidence of ESBL-E has been compared retrospectively between two French university hospitals (A and B) with different infection control policies over a 5-year long period of time (2006-2010). RESULTS: While hospital A only implemented standard precautions after identification of patients colonized with ESBL-E, hospital B recommended additional CP. During the period of the study, the ESBL-E incidence rate significantly increased in both hospitals, but no significant difference was observed between the two hospitals. CONCLUSIONS: This observational study did not reveal that additional CP measures had a greater impact on the incidence of ESBL-E in hospital settings.

Long-term effectiveness and safety of anti-TNF in pediatric-onset inflammatory bowel diseases: A population-based study.

BACKGROUND: Anti-TNF agents are the first biologic treatment option in inflammatory bowel disease (IBD). The long-term effectiveness of this strategy at the population level is poorly known, particularly in pediatric-onset IBD. METHODS: All patients diagnosed with Crohn's disease (CD) or ulcerative colitis (UC) before the age of 17 between 1988 and 2011 in the EPIMAD population-based registry were followed retrospectively until 2013. Among patients treated with anti-TNF, the cumulative probabilities of anti-TNF failure defined by primary failure, loss of response (LOR) or intolerance were evaluated. Factors associated with anti-TNF failure were investigated by a Cox model. RESULTS: Among a total of 1,007 patients with CD and 337 patients with UC, respectively 481 (48%) and 81 (24%) were treated with anti-TNF. Median age at anti-TNF initiation was 17.4 years (IQR, 15.1-20.9). Median duration of anti-TNF therapy was 20.4 months (IQR, 6.0-59.9). In CD, the probability of failure of 1st line anti-TNF at 1, 3 and 5 years was respectively 30.7%, 51.3% and 61.9% for infliximab and 25.9%, 49.3% and 57.7% for adalimumab (p = 0.740). In UC, the probability of failure of 1st line anti-TNF therapy was respectively 38.4%, 52.3% and 72.7% for infliximab and 12.5% for these 3 timepoints for adalimumab (p = 0.091). The risk of failure was maximal in the first year of treatment and LOR was the main reason for discontinuation. Female gender was associated with LOR (HR, 1.48; 95%CI 1.02-2.14) and with anti-TNF withdrawal for intolerance in CD (HR, 2.31; 95%CI 1.30-4.11) and disease duration (≥ 2 y vs. < 2 y) was associated with LOR in UC (HR, 0.37; 95%CI 0.15-0.94) in multivariate analysis. Sixty-three (13.5%) patients observed adverse events leading to termination of treatment (p = 0.57). No death, cancer or tuberculosis was observed while the patients were under anti-TNF treatment. CONCLUSION: In a population-based study of pediatric-onset IBD, about 60% in CD and 70% in UC experienced anti-TNF failure within 5 years. Loss of response account for around two-thirds of failure, both for CD and UC.

Emergency department CT examinations demonstrate no evidence of early viral circulation at the start of the COVID-19 pandemic-a multicentre epidemiological study.

BACKGROUND: Biological studies suggested that the COVID-19 outbreak in France occurred before the first official diagnosis on January 24, 2020. We investigated this controversial topic using a large collection of chest CTs performed throughout French emergency departments within 6 months before the 1st lockdown. RESULTS: Overall, 49,311 consecutive patients (median age: 60 years, 23,636/49,311 [47.9%] women) with available chest CT images and reports from 61 emergency departments between September 1, 2020, and March 16, 2020 (day before the 1st French lockdown), were retrospectively included in this multicentre study. In the macroscopic analysis of reports automatically (labelled for presence of ground glass opacities [GGOs], reticulations, and bilateral and subpleural abnormalities), we found a significant breakpoint on February 17, 2020, for the weekly time series with 1, 2 and ≥ 3 of these 4 radiological features, with 146/49,311 (0.3%) patients showing bilateral abnormalities and ground glass opacities (GGOs) from that day. According to radiologists, 22/146 (15.1%) CT images showed typical characteristics of COVID-19, including 4/146 (2.7%) before February 2020. According to hospital records, one patient remained without microbial diagnosis, two patients had proven influenza A and one patient had concomitant influenza A and mycoplasma infection. CONCLUSION: These results suggest that SARS-CoV-2 was not circulating in the areas covered by the 61 emergency departments involved in our study before the official beginning of the COVID-19 outbreak in France. In emergency patients, the strong resemblance among mycoplasma, influenza A and SARS-CoV-2 lung infections on chest CT and the nonspecificity of CT patterns in low prevalence periods is stressed. CRITICAL RELEVANCE STATEMENT: We proposed here an innovative approach to revisit a controversial 'real' start of the COVID-19 pandemic in France based on (1) a population-level approach combining text mining, time series analysis and an epidemiological dataset and (2) a patient-level approach with careful retrospective reading of chest CT scans complemented by analysis of samples performed contemporarily to the chest CT. We showed no evidence that SARS-CoV-2 was actively circulating in France before February 2020.

Nuclear speckle rejuvenation alleviates proteinopathies at the expense of YAP1.

Current treatments targeting individual protein quality control have limited efficacy in alleviating proteinopathies, highlighting the prerequisite for a common upstream druggable target capable of global proteostasis modulation. Building on our prior research establishing nuclear speckles as pivotal organelles responsible for global proteostasis transcriptional control, we aim to alleviate proteinopathies through nuclear speckle rejuvenation. We identified pyrvinium pamoate as a small-molecule nuclear speckle rejuvenator that enhances protein quality control while suppressing YAP1 signaling via decreasing the surface tension of nuclear speckle condensates through interaction with the intrinsically disordered region of nuclear speckle scaffold protein SON. In pre-clinical models, pyrvinium pamoate reduced tauopathy and alleviated retina degeneration by promoting autophagy and ubiquitin-proteasome system. Aberrant nuclear speckle morphology, reduced protein quality control and increased YAP1 activity were also observed in human tauopathies. Our study uncovers novel therapeutic targets for tackling protein misfolding disorders within an expanded proteostasis framework encompassing nuclear speckles and YAP1.

Assessing pneumococcal meningitis association with viral respiratory infections and antibiotics: insights from statistical and mathematical models.

Pneumococcus is an important human pathogen, highly antibiotic resistant and a major cause of bacterial meningitis worldwide. Better prevention requires understanding the drivers of pneumococcal infection incidence and antibiotic susceptibility. Although respiratory viruses (including influenza) have been suggested to influence pneumococcal infections, the underlying mechanisms are still unknown, and viruses are rarely considered when studying pneumococcus epidemiology. Here, we propose a novel mathematical model to examine hypothetical relationships between Streptococcus pneumoniae meningitis incidence (SPMI), acute viral respiratory infections (AVRIs) and antibiotic exposure. French time series of SPMI, AVRI and penicillin consumption over 2001-2004 are analysed and used to assess four distinct virus-bacteria interaction submodels, ascribing the interaction on pneumococcus transmissibility and/or pathogenicity. The statistical analysis reveals strong associations between time series: SPMI increases shortly after AVRI incidence and decreases overall as the antibiotic-prescription rate rises. Model simulations require a combined impact of AVRI on both pneumococcal transmissibility (up to 1.3-fold increase at the population level) and pathogenicity (up to threefold increase) to reproduce the data accurately, along with diminished epidemic fitness of resistant pneumococcal strains causing meningitis (0.97 (0.96-0.97)). Overall, our findings suggest that AVRI and antibiotics strongly influence SPMI trends. Consequently, vaccination protecting against respiratory virus could have unexpected benefits to limit invasive pneumococcal infections.

Data-driven kinematics-consistent model order reduction of fluid-structure interaction problems: application to deformable microcapsules in a Stokes flow.

In this paper, we present a generic approach of a dynamical data-driven model order reduction technique for three-dimensional fluid-structure interaction problems. A low-order continuous linear differential system is identified from snapshot solutions of a high-fidelity solver. The reduced order model (ROM) uses different ingredients like proper orthogonal decomposition (POD), dynamic mode decomposition (DMD) and Tikhonov-based robust identification techniques. An interpolation method is used to predict the capsule dynamics for any value of the governing non-dimensional parameters that are not in the training database. Then a dynamical system is built from the predicted solution. Numerical evidence shows the ability of the reduced model to predict the time-evolution of the capsule deformation from its initial state, whatever the parameter values. Accuracy and stability properties of the resulting low-order dynamical system are analysed numerically. The numerical experiments show a very good agreement, measured in terms of modified Hausdorff distance between capsule solutions of the full-order and low-order models both in the case of confined and unconfined flows. This work is a first milestone to move towards real time simulation of fluid-structure problems, which can be extended to non-linear low-order systems to account for strong material and flow non-linearities. It is a valuable innovation tool for rapid design and for the development of innovative devices.

Patient-specific finite element simulation of peripheral artery percutaneous transluminal angioplasty to evaluate the procedure outcome without stent implantation.

The purpose of this work is to present a patient-specific (PS) modeling approach for simulating percutaneous transluminal angioplasty (PTA) endovascular treatment and assessing the balloon sizing influence on short-term outcomes in peripheral arteries, i.e. without stent implantation. Two 3D PS stenosed femoral artery models, one with a dominant calcified atherosclerosis while the other with a lipidic plaque, were generated from pre-operative computed tomography angiography images. Elastoplastic constitutive laws were implemented within the plaque and artery models. Implicit finite element method (FEM) was used to simulate the balloon inflation and deflation for different sizings. Besides vessel strains, results were mainly evaluated in terms of the elastic recoil ratio (ERR) and lumen gain ratio (LGR) attained immediately after PTA. Higher LGR values were shown within the stenosed region of the lipidic patient. Simulated results also showed a direct and quantified correlation between balloon sizing and LGR and ERR for both patients after PTA, with a more significant influence on the lumen gain. The max principal strain values in the outer arterial wall increased at higher balloon sizes during inflation as well, with higher rates of increase when the plaque was calcified. Results show that our model could serve in finding a compromise for each stenosis type: maximizing the achieved lumen gain after PTA, but at the same time without damaging the arterial tissue. The proposed methodology can serve as a step toward a clinical decision support system to improve angioplasty balloon sizing selection prior to the surgery.