Tensions between end-of-life care and organ donation in controlled donation after circulatory death: ICU healthcare professionals experiences.

BACKGROUND: The development of controlled donation after circulatory death (cDCD) is both important and challenging. The tension between end-of-life care and organ donation raises significant ethical issues for healthcare professionals in the intensive care unit (ICU). The aim of this prospective, multicenter, observational study is to better understand ICU physicians' and nurses' experiences with cDCD. METHODS: In 32 ICUs in France, ICU physicians and nurses were invited to complete a questionnaire after the death of end-of-life ICU patients identified as potential cDCD donors who had either experienced the withdrawal of life-sustaining therapies alone or with planned organ donation (OD(-) and OD( +) groups). The primary objective was to assess their anxiety (State Anxiety Inventory STAI Y-A) following the death of a potential cDCD donor. Secondary objectives were to explore potential tensions experienced between end-of-life care and organ donation. RESULTS: Two hundred six ICU healthcare professionals (79 physicians and 127 nurses) were included in the course of 79 potential cDCD donor situations. STAI Y-A did not differ between the OD(-) and OD( +) groups for either physicians or nurses (STAI Y-A were 34 (27-38) in OD(-) vs. 32 (27-40) in OD( +), p = 0.911, for physicians and 32 (25-37) in OD(-) vs. 39 (26-37) in OD( +), p = 0.875, for nurses). The possibility of organ donation was a factor influencing the WLST decision for nurses only, and a factor influencing the WLST implementation for both nurses and physicians. cDCD experience is perceived positively by ICU healthcare professionals overall. CONCLUSIONS: cDCD does not increase anxiety in ICU healthcare professionals compared to other situations of WLST. WLST and cDCD procedures could further be improved by supporting professionals in making their intentions clear between end-of-life support and the success of organ donation, and when needed, by enhancing communication between ICU physician and nurses. TRIAL REGISTRATION: This research was registered in ClinicalTrials.gov (Identifier: NCT05041023, September 10, 2021).

Agreement between manual and automatic ultrasound measurement of the velocity-time integral in the left ventricular outflow tract in intensive care patients: evaluation of the AUTO-VTI® tool.

Transthoracic echocardiography is widely used in intensive care unit (ICU) to manage patients with acute circulatory failure. Recently, automated ultrasound (US) measurement applications have been developed but their clinical performance has not been evaluated yet. The aim of this study was to assess the agreement between automated and manual measurements of the velocity-time integral in the left ventricular outflow tract (VTI-LVOT) using the auto-VTI® tool. This prospective, single-center, interventional study included ICU patients with acute circulatory failure. The examination involved two successive manual measurements of VTI-LVOT (mean of 3 consecutive heartbeats in regular sinus rhythm, and 5 heartbeats in irregular rhythm), followed by a measurement using auto-VTI® software. In patients receiving a fluid challenge, trending ability in detecting fluid responsiveness was also evaluated. Seventy patients were included between January 19, 2020, and September 24, 2020, at the Nîmes University Hospital. The feasibility of the auto-VTI® was 94%. The mean difference between the two methods was 11% with limits of agreement from - 19% to 42%. The proportion of agreement at the 15% difference threshold was 68% [58%; 80%]. The precision and least significant change measured for the manual measurement of VTI were 7.4 and 10.5%, respectively, and by inference for the automated method 28% and 40%. The new auto-VTI® tool, despite interesting feasibility, demonstrated an insufficient agreement with a systematic bias and an insufficient precision limiting its implementation in critically ill patients.Clinical trial registration: ClinicalTrials.gov identifier: NCT04360304.

Angiogenesis and full thickness wound repair in a cell sheet-based vascularized skin substitute.

Skin tissue engineering is undergoing tremendous expansion as a result from clinical needs, mandatory replacement of animal models and development of new technologies. Many approaches have been used to produce vascularized skin substitutes for grafting purposes showing the presence of capillary-like structures but with limited analysis of their in vitro maturation and plasticity. Such knowledge is however important for the development of tissue substitutes with improved implantation success as well as for validation of vascularization in vitro models, including as a readout in pharmacological analyses. For optimal interactions of cells with microenvironment and vasculature, we here used a cell sheet approach consisting in the sole production of matrix by the cells. In this context, we limited the density of endothelial cells seeded for self-assembly and rather relied on the stimulation of angiogenesis for the development of an extensive connected microvascular-like network. After detailed characterization of this network, we challenged its plasticity both during and after establishment of the skin substitute. We show that fine tuning of VEGF concentration and time of application differentially affects formation of capillary-like structures and their perivascular coverage. Furthermore, we performed a deep wound assay that displayed tissue repair and angiogenesis with unique characteristics of the physiological process. These studies demonstrate the importance of cell-derived microenvironment for the establishment of mature yet dynamic vascularized skin models allowing a wide range of pharmacological and basic investigations. STATEMENT OF SIGNIFICANCE: The significant advancements in organ-on-chips and tissue engineering call for more relevant models including microvascularization with remodeling potential. While vascularized skin substitutes have been developed for years, focus has primarily been on the impact of microvascularization on implantation rather than on its in vitro characterization. We here developed a cell sheet-based vascularized skin substitute relying on angiogenesis, i.e. growth of vessel-like structures within the 3D model, rather than solely on endothelial cell self-assembly. We then characterized :1/ vascularization after modulation of angiogenic factor VEGF during the substitute construction; -2/ angiogenesis associated to tissue repair after deep mechanical wounding. These studies establish a solid physiologically relevant model for further investigation of skin cell interactions and in vitro wound healing.

Epidemiology of civilian's gunshot wound injuries admitted to intensive care unit: A retrospective, multi-center study.

BACKGROUND: Few studies investigated the outcome of patients admitted to intensive care unit (ICU) for gunshot wounds (GSW). The purpose of this study was to determine the 28-day mortality, and to analyze the impact of variables on the mortality of patients admitted to ICU with GSW in four French University Hospitals level-1 regional trauma centers. METHOD: All medical files of adult patients (above fifteen years old) admitted to four French University Hospitals level-1 regional trauma centers for GSW were retrospectively analyzed from January 1st 2015 to June 30th 2021. The primary aim was to determine 28-day death rate of patients admitted in ICU for GSW. The secondary aim was to describe biological parameters, injuries and management of patients admitted to our ICUs, and to identify the variables associated with the 28-day mortality rate. A multivariate analysis allowed determining independent mortality factors. A Kaplan-Meier analysis compared mortality according to head injury. RESULTS: Among 17,262 patients screened, 173 (1 %) were admitted for GSW and 162 were analyzed. The 28-day mortality rate was 24.7 %. 77.5 % of deaths occurred within the first 48 h after ICU admission, and 87.5 % of deaths within three days of ICU admission. The 28-day death rate of patients with head injury was significantly higher as compared to patients without head injury (p < 0.001). Out of forty deaths, twenty-three (57.5 %) were due to head injury, and nine (22.5 %) were due to bleeding. The mechanisms were assault (45.1 %), suicide (34.6 %), accident (4.9 %) and unidentified (15.4 %). In a multivariate analysis, variables associated with the 28-day death rate were age, pre-hospital Glasgow coma score, and Injury Severity Score. CONCLUSION: GSW represented 1 % of ICU admission. The 28-day mortality rate was 24.7 %. 77.5 % of deaths occurred within the first 48 h due to head injuries and bleeding. Head injuries were associated with significantly higher mortality rate.

Critical norepinephrine dose to predict early mortality during circulatory shock in intensive care: a retrospective study in 3423 ICU patients over 4-year period.

INTRODUCTION: The maximal norepinephrine (NE) dose >1 µg/kg/min during circulatory shock apparently is associated with higher mortality, but this threshold needs confirmation. This study aimed at investigating whether NE infusion at a dose >1 µg/kg/min could predict early intensive care unit (ICU) mortality (first 5 days). The secondary objective was to assess the day-by-day relationship between NE dose during the first four days of ICU stay and subsequent mortality. METHODS: We conducted a retrospective analysis of data from ICU patients receiving NE for circulatory shock at the Nimes University Hospital (France) from January/2016 to December/2019. RESULTS: 5,735 patients were admitted, 3,693 were screened and 3,423 were analyzed. NE infusion at a dose >1 µg/kg/min was associated with day-5 mortality (Hazard Ratio: 7.40, p < 0.0001). The area under the receiver operating characteristic was 0.79 to predict day-5 mortality in ICU for maximal NE > 1 µg/kg/min. The calculated threshold of 1.13 µg/kg/min for maximal NE was the best prognostic value (Sensitivity: 67%, Specificity: 80%, positive predictive value: 45%). When the 1.2 µg/kg/min threshold was crossed either on the first, second, third or fourth day of ICU stay, the probability of subsequent death was 47%, 49%, 60% and 40%, respectively. Along the first four days of ICU stay, the risk of death increased with increasing NE infusion dose. CONCLUSIONS: A NE infusion rate > 1.13 µg/kg/min predicts day-5 mortality in ICU patients with circulatory shock. The time to reach maximal NE infusion rate was shorter in survivors than in non-survivors.

Pleural lung sliding quantification using a speckle tracking technology: A feasibility study on 30 healthy volunteers.

INTRODUCTION: Speckle tracking technology quantifies lung sliding and detects lung sliding abolition in case of pneumothorax on selected ultrasound loops through the analysis of acoustic markers. OBJECTIVES: We aimed to test the ability of speckle tracking technology to quantify lung sliding using a pleural strain value (PS). METHODS: We performed a prospective study in 30 healthy volunteers in whom we assessed the pleural speckle tracking using ultrasound loops. Seven breathing conditions with and without non-invasive ventilation were tested. Two observers analyzed the ultrasound loops in four lung areas (anterior and posterior, left and right) and compared the obtained PS values. The first endpoint was to determine the feasibility of the PS measurement in different breathing conditions. The secondary endpoints were to assess the intra- and inter-observer's reliability of the measurement to compare PS values between anterior and posterior lung areas and to explore their correlations with the measured tidal volume. RESULTS: We analyzed 1624 ultrasound loops from 29 patients after one volunteer's exclusion. Feasibility of this method was rated at 90.8 [95%CI: 89.6 - 92.4]%. The intra-observer reliability measured through Intraclass Correlation Coefficients was 0.96 [95%CI: 0.91-0.98] and 0.93 [95%CI: 0.86-0.97] depending on the operator. The inter-observer reliability was 0.89 [95%CI: 0.78-0.95]. The PS values were significantly lower in the anterior lung areas compared with the posterior areas in all breathing conditions. A weak positive correlation was found in all the lung areas when a positive end expiratory pressure was applied with r = 0.26 [95%CI: 0.12;0.39]; p < 0.01. CONCLUSION: Speckle tracking lung sliding quantification with PS was applicable in most conditions with an excellent intra- and inter-observer reliability. More studies in patients under invasive mechanical ventilation are needed to explore the correlation between PS values of pleural sliding and tidal volumes. CLINICAL REGISTRATION: NCT05415605.

Neurotized profunda artery perforator flap for subtotal tongue reconstruction - Prospective case series.

BACKGROUND: Total or subtotal glossectomy defects cause significant functional deficits in swallowing and speech and subsequently impair patients' quality of life (QOL). Recently, the profunda artery perforator (PAP) flap has emerged as a potential alternative for reconstructing extensive glossectomy defects. While previous studies assessing recovery of neurotized anterolateral thigh (ALT) flaps in head and neck reconstruction reported superior sensory recovery, improved swallow function, and improved overall patient satisfaction in patients with neurotized flaps vs. non-neurotized ALT flap reconstruction, PAP flap neurotization has not been described and systematically assessed in head and neck patients. METHODS: Six patients underwent subtotal tongue reconstruction with neurotized PAP flaps at the authors' institution from May 2022 until August 2023. A branch of the posterior femoral cutaneous nerve of the PAP flap was coaptated to the lingual nerve. Two-point discrimination, Semmes-Weinstein monofilament, pain, and temperature assessments were conducted at 3, 6, and 12 months postoperatively on the neo-tongue. The MD Anderson speech and deglutition scales and the EORTC-QLQ-H&N35 were used to record functional outcomes and QOL. RESULTS: The mean age was 69 ± 4 years, and the mean body mass index was 25 ± 7 kg/m2. Neo-tongue median 2-point discrimination at the tip improved from >10 mm at 3 months to 6 mm at 12 months. All patients had protective pain and temperature perception at the neo-tongue tip at the 6-month follow-up. Speech and swallowing functions were similar at the 12-month follow-up to data on neurotized ALT flaps from literature. No neuropathic pain was reported at the donor site at the 6-month follow-up. CONCLUSIONS: This is the first case series of PAP flap neurotization in head and neck patients, suggesting potential functional advantages with minimal donor-site morbidity. LEVEL OF EVIDENCE: V Case Series.

Diagnostic performance of a clinical ultrasound-based algorithm for acute heart failure in patients presenting to the emergency department with dyspnea. / Rendimiento diagnóstico de un algoritmo basado en ecografía clínica para el diagnóstico de insuficiencia cardiaca aguda en pacientes que consultan en urgencias por disnea.

OBJECTIVES: To study the diagnostic performance of an ultrasound-based algorithm that includes the deceleration time (DT) of early mitral filling to establish a diagnosis of acute heart failure (AHF) in patients who come to an emergency department because of dyspnea. MATERIAL AND METHODS: Prospective analysis in a convenience sample of patients who came to a hospital emergency department with acute dyspnea. The algorithm included ultrasound findings and 4 echocardiographic findings as follows: mitral annular plane systolic excursion, Doppler mitral flow velocity, tissue Doppler imaging measure of the lateral annulus, and the DT of early mitral filling. The definitive diagnosis was made by 2 physicians blinded to each other's diagnosis and the ultrasound findings. RESULTS: A total of 166 adult patients with a mean (SD) age of 76 (13) years were included; 79 (48%) were women. AHF was the definitive diagnosis in 62 patients (37%). Diagnostic agreement was good between the 2 physicians (κ = 0.71). The algorithm classified all the patients, and there were no undetermined diagnoses. Diagnostic performance indicators for the ultrasound-based algorithm integrating early DT findings were as follows: area under the receiver operating characteristic curve, 0.91 (95% CI, 0.86-0.96); sensitivity, 87% (95% CI, 76%-94%); specificity, 95% (95% CI, 89%-98%); positive likelihood ratio, 18.1 (95% CI, 7.7-42.8); and negative likelihood ratio, 0.14 (95% CI, 0.07-0.26). CONCLUSION: The ultrasound-based algorithm integrating the DT of early mitral filling performs well for diagnosing AHF in emergency patients with dyspnea. The inclusion of early DT allows all patients to be diagnosed.

OBJETIVO: Analizar el rendimiento diagnóstico de un algoritmo ecográfico que incluye el tiempo de desaceleración precoz del flujo mitral (TD) para establecer el diagnóstico de insuficiencia cardiaca aguda (ICA) en pacientes que consultan en un servicio de urgencias hospitalario (SUH) por disnea. METODO: Análisis prospectivo de una muestra de conveniencia de pacientes que consultan por disnea aguda en un SUH. El algoritmo ecográfico incluyó la ecografía pulmonar y cuatro parámetros ecocardiográficos, se midió MAPSE (desplazamiento sistólico del plano del anillo mitral), medidas doppler de flujo mitral, medidas doppler tisular en el anillo mitral lateral y TD. El diagnóstico final fue asignado por 2 médicos ciegos entre sí y a los hallazgos ecográficos. RESULTADOS: Se incluyeron 166 pacientes adultos, la edad media fue de 76 años (DE 13) y 79 eran mujeres (48%). Hubo 62 pacientes (37%) con un diagnóstico final de ICA. La concordancia entre asignadores fue buena para el diagnóstico de ICA (κ = 0,71). El algoritmo clasificó a todos los pacientes, no hubo ningún diagnóstico indeterminado. El rendimiento diagnóstico del algoritmo mostró un área bajo la curva de 0,91 (IC 95%: 0,86-0,96), sensibilidad del 87% (IC 95%: 76%-94%), especificidad del 95% (IC 95%: 89%-98%), razón de verosimilitud positiva del 18,1 (IC 95%: 7,7-42,8), razón de verosimilitud negativa del 0,14 (IC 95%: 0,07-0,26). CONCLUSIONES: Un algoritmo ecográfico que incluye el TD tiene un buen rendimiento para el diagnóstico de ICA en pacientes que acuden a SUH por disnea. Además, el uso de TD permite clasificar a todos los pacientes.

The proteome of bacterial membrane vesicles in Escherichia coli-a time course comparison study in two different media.

Introduction: Bacteria inhabit the in- and outside of the human body, such as skin, gut or the oral cavity where they play an innoxious, beneficial or even pathogenic role. It is well known that bacteria can secrete membrane vesicles (MVs) like eukaryotic cells with extracellular vesicles (EVs). Several studies indicate that bacterial membrane vesicles (bMVs) play a crucial role in microbiome-host interactions. However, the composition of such bMVs and their functionality under different culture conditions are still largely unknown. Methods: To gain a better insight into bMVs, we investigated the composition and functionality of E. coli (DSM 105380) bMVs from the culture media Lysogeny broth (LB) and RPMI 1640 throughout the different phases of growth (lag-, log- and stationary-phase). bMVs from three time points (8 h, 54 h, and 168 h) and two media (LB and RPMI 1640) were isolated by ultracentrifugation and analyzed using nanoparticle tracking analysis (NTA), cryogenic electron microscopy (Cryo-EM), conventional transmission electron microscopy (TEM) and mass spectrometry-based proteomics (LC-MS/MS). Furthermore, we examined pro-inflammatory cytokines IL-1ß and IL-8 in the human monocyte cell line THP-1 upon bMV treatment. Results: Particle numbers increased with inoculation periods. The bMV morphologies in Cryo-EM/TEM were similar at each time point and condition. Using proteomics, we identified 140 proteins, such as the common bMV markers OmpA and GroEL, present in bMVs isolated from both media and at all time points. Additionally, we were able to detect growth-condition-specific proteins. Treatment of THP-1 cells with bMVs of all six groups lead to significantly high IL-1ß and IL-8 expressions. Conclusion: Our study showed that the choice of medium and the duration of culturing significantly influence both E. coli bMV numbers and protein composition. Our TEM/Cryo-EM results demonstrated the presence of intact E. coli bMVs. Common E. coli proteins, including OmpA, GroEL, and ribosome proteins, can consistently be identified across all six tested growth conditions. Furthermore, our functional assays imply that bMVs isolated from the six groups retain their function and result in comparable cytokine induction.

Consistency of data reporting in fluid responsiveness studies in the critically ill setting: the CODEFIRE consensus from the Cardiovascular Dynamic section of the European Society of Intensive Care Medicine.

PURPOSE: To provide consensus recommendations regarding hemodynamic data reporting in studies investigating fluid responsiveness and fluid challenge (FC) use in the intensive care unit (ICU). METHODS: The Executive Committee of the European Society of Intensive Care Medicine (ESICM) commissioned and supervised the project. A panel of 18 international experts and a methodologist identified main domains and items from a systematic literature, plus 2 ancillary domains. A three-step Delphi process based on an iterative approach was used to obtain the final consensus. In the Delphi 1 and 2, the items were selected with strong (≥ 80% of votes) or week agreement (70-80% of votes), while the Delphi 3 generated recommended (≥ 90% of votes) or suggested (80-90% of votes) items (RI and SI, respectively). RESULTS: We identified 5 main domains initially including 117 items and the consensus finally resulted in 52 recommendations or suggestions: 18 RIs and 2 SIs statements were obtained for the domain "ICU admission", 11 RIs and 1 SI for the domain "mechanical ventilation", 5 RIs for the domain "reason for giving a FC", 8 RIs for the domain pre- and post-FC "hemodynamic data", and 7 RIs for the domain "pre-FC infused drugs". We had no consensus on the use of echocardiography, strong agreement regarding the volume (4 ml/kg) and the reference variable (cardiac output), while weak on administration rate (within 10 min) of FC in this setting. CONCLUSION: This consensus found 5 main domains and provided 52 recommendations for data reporting in studies investigating fluid responsiveness in ICU patients.

Early temporary mechanical circulatory support for cardiogenic shock: Real-life data from a regional cardiac assistance network.

BACKGROUND: Temporary mechanical circulatory support as well as multidisciplinary team approach in a regional care organization might improve survival of cardiogenic shock. No study has evaluated the relative effect of each temporary mechanical circulatory support on mortality in the context of a regional network. METHODS: Prospective observational data were retrieved from patients consecutively admitted with cardiogenic shock to the intensive care units in 3 centers organized into a regional cardiac assistance network. Temporary mechanical circulatory support indication was decided by a heart team, based on the initial shock severity or if shock was refractory to medical treatment within 24 hours of admission. A propensity score for circulatory support use was used as an adjustment co-variable to emulate a target trial. The primary endpoint was in-hospital mortality. RESULTS: Two hundred and forty-six patients were included in the study (median age: 59.5 years, 71.9% male): 121 received early mechanical assistance. The main etiologies were acute myocardial infraction (46.8%) and decompensated heart failure (27.2%). Patients who received early mechanical assistance had more severe conditions than other patients. Their crude in-hospital mortality was 38% and 22.4% in other patients but adjusted in-hospital mortality was not different (hazard ratio 0.91, 95% CI:0.65-1.26). Patients with mechanical assistance had a higher rate of complications than others with longer Intensive Care Unit and hospital stays. CONCLUSIONS: In the conditions of a cardiac assistance regional network, in-hospital mortality was not improved by early mechanical assistance implantation. A high incidence of complications of temporary mechanical circulatory support may have jeopardized its potential benefit.

Impact of adjuvant radiochemotherapy on free flap volume in head and neck reconstruction: A systematic review and meta-analysis.

BACKGROUND: Limited data exist regarding the effect of adjuvant radiochemotherapy on free flap volume in head and neck reconstruction. However, an adequate free flap volume is an important predictor of functional and patient-reported outcomes in head and neck reconstruction. METHODS: A systematic review of Medline, Embase, and the Cochrane Central Register of Controlled Trials was conducted using the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. A total of 6710 abstracts were screened, and 36 full-text papers were reviewed. Nineteen studies met the inclusion criteria and were used to extract data for this analysis. RESULTS: A meta-analysis of 14 two-arm studies comparing the impact of adjuvant radiotherapy versus no adjuvant radiotherapy was performed. The main analysis revealed that 6 months postoperatively, irradiated flaps showed a significant reduction of volume (average, 9.4%) compared to nonirradiated flaps. The average interpolated pooled flap volumes 6 months postoperatively were 76.4% in irradiated flaps and 81.8% in nonirradiated flaps. After a median postoperative follow-up of 12 months, the total flap volume was 62.6% for irradiated flaps and 76% for nonirradiated flaps. Four studies reported that chemotherapy had no significant impact on free flap volume. CONCLUSIONS: Compared to nonirradiated flaps, irradiated flaps were significantly reduced in volume (range, 5% to 15.5%). Clinicians should take this into account when planning the surgical reconstruction of head and neck defects. Conducting large-scale prospective studies with standardized protocols and well-defined follow-up measurements could contribute to defining the ideal, personalized free flap volume for optimal function and patient-reported outcomes.

Low Percentage of Perforin-Expressing NK Cells during Severe SARS-CoV-2 Infection: Consumption Rather than Primary Deficiency.

Genetic defects in the ability to deliver effective perforin have been reported in patients with hemophagocytic lymphohistiocytosis. We tested the hypothesis that a primary perforin deficiency might also be causal in severe SARS-CoV-2 infection. We recruited 54 volunteers confirmed as being SARS-CoV-2-infected by RT-PCR and admitted to intensive care units or non-intensive care units and age- and sex-matched healthy controls. Compared with healthy controls, the percentage of perforin-expressing CD3-CD56+ NK cells quantified by flow cytometry was low in COVID-19 patients (69.9 ± 17.7 versus 78.6 ± 14.6%, p = 0.026). There was no correlation between the proportions of perforin-positive NK cells and T8 lymphocytes. Moreover, the frequency of NK cells producing perforin was neither linked to disease severity nor predictive of death. Although IL-6 is known to downregulate perforin production in NK cells, we did not find any link between perforin expression and IL-6 plasma level. However, we unveiled a negative correlation between the degranulation marker CD107a and perforin expression in NK cells (r = -0.488, p = 10-4). PRF1 gene expression and the frequency of NK cells harboring perforin were normal in patients 1 y after acute SARS-CoV-2 infection. A primary perforin defect does not seem to be a driver of COVID-19 because NK perforin expression is 1) linked neither to T8 perforin expression nor to disease severity, 2) inversely correlated with NK degranulation, and 3) normalized at distance from acute infection. Thus, the cause of low frequency of perforin-positive NK cells appears, rather, to be consumption.

Towards a qualitative theory of the interruption of eating behavior change.

The poor maintenance of eating behavior change is one of the main obstacles to minimizing weight regain after weight loss during diets for non-surgical care of obese or overweight patients. We start with a known informal explanation of interruption in eating behavior change during severe restriction and formalize it as a causal network involving psychological variables, which we extend with energetic variables governed by principles of thermodynamics. The three core phenomena of dietary behavior change, i.e., non-initiation, initiation followed by discontinuation and initiation followed by non-discontinuation, are expressed in terms of the value of the key variable representing mood or psychological energy, the fluctuation of which is the result of three causal relationships. Based on our experimental knowledge of the time evolution profile of the three causal input variables, we then proceed to a qualitative analysis of the resulting theory, i.e., we consider an over-approximation of it which, after discretization, can be expressed in the form of a finite integer-based model. Using Answer Set Programming, we show that our formal model faithfully reproduces the three phenomena and, under a certain assumption, is minimal. We generalize this result by providing all the minimal models reproducing these phenomena when the possible causal relationships exerted on mood are extended to all the other variables (not just those assumed in the informal explanation), with arbitrary causality signs. Finally, by a direct analytical resolution of an under-approximation of our theory, obtained by assuming linear causalities, as a system of linear ODEs, we find exactly the same minimal models, proving that they are also equal to the actual minimal models of our theory since these are framed below and above by the models of the under-approximation and the over-approximation. We determine which parameters need to be person-specific and which can be considered invariant, i.e., we explain inter-individual variability. Our approach could pave the way for universally accepted theories in the field of behavior change and, more broadly, in other areas of psychology.

Repetitive mRNA vaccination is required to improve the quality of broad-spectrum anti-SARS-CoV-2 antibodies in the absence of CXCL13.

Since the initial spread of severe acute respiratory syndrome coronavirus 2 infection, several viral variants have emerged and represent a major challenge for immune control, particularly in the context of vaccination. We evaluated the quantity, quality, and persistence of immunoglobulin G (IgG) and IgA in individuals who received two or three doses of messenger RNA (mRNA) vaccines, compared with previously infected vaccinated individuals. We show that three doses of mRNA vaccine were required to match the humoral responses of preinfected vaccinees. Given the importance of antibody-dependent cell-mediated immunity against viral infections, we also measured the capacity of IgG to recognize spike variants expressed on the cell surface and found that cross-reactivity was also strongly improved by repeated vaccination. Last, we report low levels of CXCL13, a surrogate marker of germinal center activation and formation, in vaccinees both after two and three doses compared with preinfected individuals, providing a potential explanation for the short duration and low quality of Ig induced.

Papillary and reticular fibroblasts generate distinct microenvironments that differentially impact angiogenesis.

Papillary and reticular dermis show distinct extracellular matrix (ECM) and vascularization corresponding to their specific functions. These characteristics are associated with gene expression patterns of fibroblasts freshly isolated from their native microenvironment. In order to assess the relevance of these fibroblast subpopulations in a tissue engineering context, we investigated their contribution to matrix production and vascularization using cell sheet culture conditions. We first performed RNA-seq differential expression analysis to determine whether several rounds of cell amplification and high-density culture affected their gene expression profile. Bioinformatics analysis revealed that expression of angiogenesis-related and matrisome gene signatures were maintained, resulting in papillary and reticular ECMs that differ in composition and structure. The impact of secreted or ECM-associated factors was then assessed using two independent 3D angiogenesis assays: -1/ a fibrin hydrogel-based assay allowing investigation of diffusible secreted factors, -2/ a scaffold-free cell-sheet based assay for investigation of fibroblast-produced microenvironment. These analyses revealed that papillary fibroblasts secrete highly angiogenic factors and produce a microenvironment characterised by ECM remodelling capacity and dense and branched microvascular network, whereas reticular fibroblasts produced more structural core components of the ECM associated with less branched and larger vessels. These features mimick the characteristics of both the ECM and the vasculature of dermis subcompartments. In addition to showing that skin fibroblast populations differentially regulate angiogenesis via both secreted and ECM factors, our work emphasizes the importance of papillary and reticular fibroblasts for engineering and modelling dermis microenvironment and vascularization. STATEMENT OF SIGNIFICANCE: Recent advances have brought to the forefront the central role of microenvironment and vascularization in tissue engineering for regenerative medicine and microtissue modelling. We have investigated the role of papillary and reticular fibroblast subpopulations using scaffold-free cell sheet culture. This approach provides differentiated cells conditions allowing the production of their own microenvironment. Analysis of gene expression profiles and characterisation of the matrix produced revealed strong and specific angiogenic properties that we functionally characterized using 3D angiogenesis models targeting the respective role of either secreted or matrix-bound factors. This study demonstrates the importance of cell-generated extracellular matrix and questions the importance of cell source and the relevance of hydrogels for developing physio-pathologically relevant tissue engineered substitutes.

Practical considerations for individualizing drug dosing in critically ill adults receiving renal replacement therapy.

Critically ill patients with sepsis admitted to the intensive care unit (ICU) often present with or develop renal dysfunction requiring renal replacement therapy (RRT) in addition to antimicrobial therapy. While early and appropriate antimicrobials for sepsis have been associated with an increased probability of survival, adequate dosing is also required in these patients. Adequate dosing of antimicrobials refers to dosing strategies that achieve serum drug levels at the site of infection that are able to provide a microbiological and/or clinical response while avoiding toxicity from excessive antibiotic exposure. Therapeutic drug monitoring (TDM) is the recommended strategy to achieve this goal, however, TDM is not routinely available in all ICUs and for all antimicrobials. In the absence of TDM, clinicians are therefore required to make dosing decisions based on the clinical condition of the patient, the causative organism, the characteristics of RRT, and an understanding of the physicochemical properties of the antimicrobial. Pharmacokinetics (PK) of antimicrobials can be highly variable between critically ill patients and also within the same patient over the course of their ICU stay. The initiation of RRT, which can be in the form of intermittent hemodialysis, continuous, or prolonged intermittent therapy, further complicates the predictability of drug disposition. This variability highlights the need for individualized dosing. This review highlights the practical considerations for the clinician for antimicrobial dosing in critically ill patients receiving RRT.