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1H–1H coupling constants are one of the primary sources of information for nuclear magnetic resonance (NMR) structural analysis. Several selective 2DJ experiments have been proposed that allow for their individual measurement at pure shift resolution. However, all of these experiments fail in the not uncommon case when coupled protons have very close chemical shifts. First, the coupling between protons with overlapping multiplets is inaccessible due to the inability of a frequency-selective pulse to invert just one of them. Second, the strong coupling condition affects the accuracy of coupling measurements involving third spins. These shortcomings impose a limit on the effectiveness of state-of-the-art experiments, such as G-SERF or PSYCHEDELIC. Here, we introduce two new and complementary selective 2DJ experiments that we coin SERFBIRD and SATASERF. These experiments overcome the aforementioned issues by utilizing the 13C satellite signals at natural isotope abundance, which resolves the chemical shift degeneracy. We demonstrate the utility of these experiments on the tetrasaccharide stachyose and the challenging case of norcamphor, for the latter achieving measurement of all JHHcouplings, while only a few were accessible with PSYCHEDELIC. The new experiments are applicable to any organic compound and will prove valuable for configurational and conformational analyses.

Ex vivo lung perfusion (EVLP) is a valuable method for expanding the lung donor pool. Its indications currently differ across centers. This national retrospective cohort study aimed to describe the profile of donors with lungs transplanted after EVLP and determine the effectiveness of EVLP on lung utilization. We included brain-dead donors with at least one lung offered between 2012 and 2019 in France. Lungs transplanted without or after EVLP were compared with those that were rejected. Donor group phenotypes were determined with multiple correspondence analysis (MCA). The association between donor factors and lung transplantation was assessed with a multivariable multinomial logistic regression. MCA revealed that donors whose lungs were transplanted after EVLP had profiles similar to the donors whose lungs were declined and quite different from those of donors with lungs transplanted without EVLP. Donor predictors of graft nonuse included age ≥50 years, smoking history, PaO2/FiO2ratio ≤300 mmHg, abnormal chest imaging, and purulent secretions. EVLP increased utilization of lungs from donors with a smoking history, PaO2/FiO2ratio ≤300 mmHg, and abnormal chest imaging.

Graft allocation rules for heart transplantation are necessary because of the shortage of heart donors, resulting in high waitlist mortality. The Agence de la biomédecine is the agency in charge of the organ allocation system in France. Assessment of the 2004 urgency‐based allocation system identified challenging limitations. A new system based on a score ranking all candidates was implemented in January 2018. In the revised system, medical urgency is defined according to candidate characteristics rather than the treatment modalities, and an interplay between urgency, donor‐recipient matching, and geographic sharing was introduced. In this article, we describe in detail the new allocation system and compare these allocation rules to Eurotransplant and US allocation policies. This article describes the 2018 French donor heart allocation system, which ranks candidates according to a waitlist mortality risk model based on candidates’ characteristics together with a comprehensive donor‐recipient matching and gravity geographic sharing model balancing medical urgency and graft traveling time.

The new French heart allocation system is designed to minimize waitlist mortality and extend the donor pool without a detrimental effect on posttransplant survival. This study was designed to construct a 1‐year posttransplant graft‐loss risk score incorporating recipient and donor characteristics. The study included all adult first single‐organ recipients transplanted between 2010 and 2014 (N = 1776). This population was randomly divided in a 2:1 ratio into derivation and validation cohorts. The association of variables with 1‐year graft loss was determined with a mixed Cox model with center as random effect. The predictors were used to generate a transplant‐risk score (TRS). Donor‐recipient matching was assessed using 2 separate recipient‐ and donor‐risk scores. Factors associated with 1‐year graft loss were recipient age >50 years, valvular cardiomyopathy and congenital heart disease, previous cardiac surgery, diabetes, mechanical ventilation, glomerular filtration rate and bilirubin, donor age >55 years, and donor sex: female. The C‐index of the final model was 0.70. Correlation between observed and predicted graft loss rate was excellent for the overall cohort (r= 0.90). Hearts from high‐risk donors transplanted to low‐risk recipients had similar survival as those from low‐risk donors. The TRSprovides an accurate prediction of 1‐year graft‐loss risk and allows optimal donor‐recipient matching. This study presents the 1‐year posttransplant risk score, which is being incorporated into the French cardiac allocation system.

This French study shows that a new Candidate Risk Score predicts waitlist mortality in heart transplant candidates without the need to consider hospitalization or inotropic infusion that depend on medical practices. Also, waitlist mortality of patients on mechanical bridge therapy is similar to that of patients without bridge therapy.

This retrospective analysis of a French national registry including 866 patients shows survival benefit after heart transplantation even in patients on veno-arterial extracorporeal membrane oxygenation, suggesting that transplantation is an acceptable therapy in selected patients of this group.

Le nombre total de candidats pour un greffon est de 2,1.

In addition to their well-known DNA-binding properties, homeodomains have the ability to efficiently translocate across biological membranes through still poorly-characterized mechanisms. To date, most biophysical studies addressing the mechanisms of internalization have focused on small synthetic peptides rather than full-length globular homeodomains. In this work, we characterized the conformational properties of chicken Engrailed 2 homeodomain (En2HD) in aqueous solution and in membrane mimetic environments using circular dichroism, Trp fluorescence, and NMR spectroscopy. En2HD adopts a well-defined three-helical bundle fold in aqueous solution. The Trp-48 residue, which is critical for internalization, is fully buried in the hydrophobic core. Circular dichroism and fluorescence reveal that a conformational transition occurs in anionic lipid vesicles and in micelles. En2HD loses its native three-dimensional structure in micellar environments but, remarkably, near-native helical secondary structures are maintained. Long-range interactions could be detected using site-directed spin labels, indicating that the three helices do not adopt extended orientations. Noncovalent paramagnetic probes yielded information about helix positioning and unveiled the burial of critical aromatic and basic residues within the micelles. Our results suggest that electrostatic interactions with membranes may be determinant in inducing a conformational change enabling Trp-48 to insert into membranes.

In France, foreign patients, whether resident or not in France, can register on the national waiting list under certain conditions. We compared waiting time to kidney transplantation, the level of HLA matching and graft cold ischemia time between foreign patients and French patients living in mainland France or in French overseas territories (FOT).

Tau proteins aggregate into filaments in brain cells in Alzheimer's disease and related disorders referred to as tauopathies. Here, we used fragments of camelid heavy-chain-only antibodies (VHHs or single domain antibody fragments) targeting Tau as immuno-modulators of its pathologic seeding. A VHH issued from the screen against Tau of a synthetic phage-display library of humanized VHHs was selected for its capacity to bind Tau microtubule-binding domain, composing the core of Tau fibrils. This parent VHH was optimized to improve its biochemical properties and to act in the intra-cellular compartment, resulting in VHH Z70. VHH Z70 precisely binds the PHF6 sequence, known for its nucleation capacity, as shown by the crystal structure of the complex. VHH Z70 was more efficient than the parent VHH to inhibit in vitroTau aggregation in heparin-induced assays. Expression of VHH Z70 in a cellular model of Tau seeding also decreased the aggregation-reporting fluorescence signal. Finally, intra-cellular expression of VHH Z70 in the brain of an established tauopathy mouse seeding model demonstrated its capacity to mitigate accumulation of pathological Tau. VHH Z70, by targeting Tau inside brain neurons, where most of the pathological Tau resides, provides an immunological tool to target the intra-cellular compartment in tauopathies.