Safety and efficacy of a strategy of vitamin K antagonist reversal with prothrombin complex concentrates compared to vitamin K in patients with hip fracture.

Background: Increased preoperative delay in patients with hip fractures may be responsible for increased morbidity and mortality. We hypothesized that a strategy of reversal of vitamin K antagonist (VKA) by prothrombin complexes concentrates (PCCs), as compared to vitamin K, is safe and reduces preoperative delay and hospital length of stay (LOS). Methods: In this pilot study, we reviewed the records of patients admitted to a university-affiliated hospital for hip fracture between Jan. 1, 2012, and Dec. 31, 2016, who were taking VKA. Patients were stratified according to reversal strategy (vitamin K v. PCC). Adverse effects, time to surgery, LOS and mortality were collected from the electronic medical record and were compared between the 2 study groups and a control group not treated with VKA. Results: A total of 141 patients were included in the study: 65 in the vitamin K group, 26 in the PCC group and 50 in the control group. The median preoperative delay in the PCC group (20 h [interquartile range (IQR)] 13-25 h]) and the control group (20 h [IQR 15-33 h]) was lower than that in the vitamin K group (45 h [IQR 31-52 h]) (p < 0.001). Patients in the PCC group had a shorter median hospital LOS than those in the vitamin K group (6 d [IQR 4-9 d] v. 8 d [IQR 6-11 d], p < 0.05). No difference was observed in the proportion of patients who received a red blood cell transfusion, or had thrombotic or hemorrhagic complications. No difference in mortality at 12 months was observed between the groups. Conclusion: In patients with hip fracture, the use of PCCs as compared to vitamin K to reverse the effect of VKA significantly reduced preoperative delay and hospital LOS, and was not associated with an increase in the rates of thrombotic or hemorrhagic complications. Prospective studies involving a greater number of patients are required to confirm these promising results.

Contexte: L'allongement du délai préopératoire chez les patients atteints d'une fracture de la hanche pourrait expliquer l'augmentation de la morbidité et de la mortalité. Selon notre hypothèse, une stratégie d'inversion des antagonistes de la vitamine K (AVK) au moyen de concentrés de complexes prothrombiques (CCP), plutôt que de vitamine K, est sécuritaire et réduit le délai préopératoire et la durée du séjour hospitalier. Méthodes: Pendant cette étude pilote, nous avons passé en revue les dossiers de patients sous AVK admis dans un centre universitaire pour fracture de la hanche entre le 1er janvier 2012 et le 31 décembre 2016. Les patients ont été stratifiés selon la stratégie d'inversion choisie (vitamine K c. CCP). Les effets indésirables, le délai préopératoire, la durée du séjour hospitalier et la mortalité ont été recueillis à partir des dossiers médicaux électroniques et ont été comparés entre les 2 groupes de l'étude et un groupe témoin non sous AVK. Résultats: En tout, 141 patients ont été inclus dans l'étude, 65 dans le groupe sous vitamine K, 26 dans le groupe sous CCP et 50 dans le groupe témoin. Le délai préopératoire médian pour le groupe sous CCP (20 h [éventail interquartile (ÉIQ)] 13­25 h]) et le groupe témoin (20 h [ÉIQ 15­33 h]) a été plus bref que pour le groupe sous vitamine K (45 h [ÉIQ 31­52 h]) (p < 0,001). Les patients du groupe sous CCP ont eu un séjour hospitalier médian plus bref que les patients du groupe sous vitamine K (6 j [ÉIQ 4­9 j] c. 8 j [ÉIQ 6­11 j]) (p < 0,05). Aucune différence n'a été observée quant à la proportion de patients ayant reçu une transfusion de culot globulaire ou ayant manifesté des complications thrombotiques ou hémorragiques. Aucune différence quant à la mortalité à 12 mois n'a été observée entre les groupes. Conclusion: Chez les patients atteints d'une fracture de la hanche, l'utilisation des CCP plutôt que de la vitamine K pour inverser l'effet des AVK a significativement abrégé le délai préopératoire et la durée du séjour hospitalier, et n'a pas été associée à une augmentation des taux de complications thrombotiques ou hémorragiques. Des études prospectives sur un plus grand nombre de patients sont nécessaires pour confirmer ces résultats prometteurs.

Mutation update for the GPC3 gene involved in Simpson-Golabi-Behmel syndrome and review of the literature.

Simpson-Golabi-Behmel syndrome (SGBS) is an X-linked multiple congenital anomalies and overgrowth syndrome caused by a defect in the glypican-3 gene (GPC3). Until now, GPC3 mutations have been reported in isolated cases or small series and the global genotypic spectrum of these mutations has never been delineated. In this study, we review the 57 previously described GPC3 mutations and significantly expand this mutational spectrum with the description of 29 novel mutations. Compiling our data and those of the literature, we provide an overview of 86 distinct GPC3 mutations identified in 120 unrelated families, ranging from single nucleotide variations to complex genomic rearrangements and dispersed throughout the entire coding region of GPC3. The vast majority of them are deletions or truncating mutations (frameshift, nonsense mutations) predicted to result in a loss-of-function. Missense mutations are rare and the two which were functionally characterized, impaired GPC3 function by preventing GPC3 cleavage and cell surface addressing respectively. This report by describing for the first time the wide mutational spectrum of GPC3 could help clinicians and geneticists in interpreting GPC3 variants identified incidentally by high-throughput sequencing technologies and also reinforces the need for functional validation of non-truncating mutations (missense, in frame mutations, duplications).

Self-assembly of a barnacle cement protein into intertwined amyloid fibres and determination of their adhesive and viscoelastic properties.

The stalked barnacle Pollicipes pollicipes uses a multi-protein cement to adhere to highly varied substrates in marine environments. We investigated the morphology and adhesiveness of a component 19 kDa protein in barnacle cement gland- and seawater-like conditions, using transmission electron microscopy and state-of-the art scanning probe techniques. The protein formed amyloid fibres after 5 days in gland-like but not seawater conditions. After 7-11 days, the fibres self-assembled under gland-like conditions into large intertwined fibrils of up to 10 µm in length and 200 nm in height, with a distinctive twisting of fibrils evident after 11 days. Atomic force microscopy (AFM)-nanodynamic mechanical analysis of the protein in wet conditions determined E' (elasticity), E'' (viscosity) and tan δ values of 2.8 MPa, 1.2 MPa and 0.37, respectively, indicating that the protein is a soft and viscoelastic material, while the adhesiveness of the unassembled protein and assembled fibres, measured using peak force quantitative nanomechanical mapping, was comparable to that of the commercial adhesive Cell-Tak™. The study provides a comprehensive insight into the nanomechanical and viscoelastic properties of the barnacle cement protein and its self-assembled fibres under native-like conditions and may have application in the design of amyloid fibril-based biomaterials or bioadhesives.

Molecular mechanisms mediating stiffening in the mechanically adaptable connective tissues of sea cucumbers.

Mutable collagenous tissues (MCTs) from echinoderms (e.g., sea stars, sea urchins) possess the remarkable ability to change their mechanical properties rapidly and reversibly thanks to the release of effector molecules regulating the number of cross-links between collagen fibrils. Among these effector molecules, tensilin has been identified as a stiffening factor in sea cucumber MCTs. Since its discovery and description twenty years ago, tensilin orthologs have been identified in a few sea cucumber species but no novel information about its molecular mode of action has been reported. In this study, using a combination of in silico analyses, we identified the tensilin present in the dermis of Holothuria forskali, Hf-(D)Tensilin. Anti-peptide antibodies showed that this protein is localised in the secretory granules of type 2 juxtaligamental-like cells, a MCT specific cell type. We then used the bacterium E. coli to produce recombinantly Hf-(D)Tensilin and confirmed its stiffening effect on pieces of the dermis and its aggregation effect on collagen fibrils extracted from the sea cucumber dermis. To investigate how tensilin can cross-bridge collagen fibrils, truncated recombinant tensilins were also produced and used in combination with various compounds. Results suggest that two types of interactions contribute to the aggregation effect of tensilin on the fibrils: (1) the N-terminal NTR TIMP like domain of the protein interacts strongly with sulfated GAGs attached to the surface of the collagen fibrils, and (2) the C-terminal part of the protein is involved in its dimerisation/oligomerisation through ionic but possibly also cation-π and hydrophobic interactions.

Disentangling the Roles of Functional Domains in the Aggregation and Adsorption of the Multimodular Sea Star Adhesive Protein Sfp1.

Sea stars can adhere to various underwater substrata using an adhesive secretion of which Sfp1 is a major component. Sfp1 is a multimodular protein composed of four subunits (Sfp1 Alpha, Beta, Delta, and Gamma) displaying different functional domains. We recombinantly produced two fragments of Sfp1 comprising most of its functional domains: the C-terminal part of the Beta subunit (rSfp1 Beta C-term) and the Delta subunit (rSfp1 Delta). Surface plasmon resonance analyses of protein adsorption onto different model surfaces showed that rSfp1 Beta C-term exhibits a significantly higher adsorption than the fibrinogen control on hydrophobic, hydrophilic protein-resistant, and charged self-assembled monolayers, while rSfp1 Delta adsorbed more on negatively charged and on protein-resistant surfaces compared to fibrinogen. Truncated recombinant rSfp1 Beta C-term proteins were produced in order to investigate the role of the different functional domains in the adsorption of this protein. The analysis of their adsorption capacities on glass showed that two mechanisms are involved in rSfp1 Beta C-term adsorption: (1) one mediated by the EGF-like domain and involving Ca2+ and Mg2+ ions, and (2) one mediated by the sequence of Sfp1 Beta with no homology with known functional domain in databases, in the presence of Na+, Ca2+ and Mg2+ ions.

Sea star-inspired recombinant adhesive proteins self-assemble and adsorb on surfaces in aqueous environments to form cytocompatible coatings.

Sea stars adhere to various underwater substrata using an efficient protein-based adhesive secretion. The protein Sfp1 is a major component of this secretion. In the natural glue, it is cleaved into four subunits (Sfp1 Alpha, Beta, Delta and Gamma) displaying specific domains which mediate protein-protein or protein-carbohydrate interactions. In this study, we used the bacterium E. coli to produce recombinantly two fragments of Sfp1 comprising most of its functional domains: the C-terminal part of the Beta subunit (rSfp1 Beta C-term) and the Delta subunit (rSfp1 Delta). Using native polyacrylamide gel electrophoresis and size exclusion chromatography, we show that the proteins self-assemble and form oligomers and aggregates in the presence of NaCl. Moreover, they adsorb onto glass and polystyrene upon addition of Na+ and/or Ca2+ ions, forming homogeneous coatings or irregular meshworks, depending on the cation species and concentration. We show that coatings made of each of the two proteins have no cytotoxic effects on HeLa cells and even increase their proliferation. We propose that the Sfp1 recombinant protein coatings are valuable new materials with potential for cell culture or biomedical applications. STATEMENT OF SIGNIFICANCE: Biological adhesives offer impressive performance in their natural context and, therewith, the potential to inspire the development of advanced biomaterials for an increasing variety of applications in medicine or in material sciences. To date, most marine adhesive proteins that have been produced recombinantly in order to develop bio-inspired adhesives are small proteins from mussels and barnacles. Here, we produced two multi-modular proteins based on the sequence of Sfp1, a major protein from sea star adhesive secretion. These two proteins comprise most of Sfp1 functional domains which mediate protein-protein and protein-carbohydrate interactions. We characterized the two recombinant proteins with an emphasis on functional characteristics such as self-assembly, adsorption and cytocompatibility. We discuss their potential as biomaterials.

Interspecies comparison of sea star adhesive proteins.

Sea stars use adhesive secretions to attach their numerous tube feet strongly and temporarily to diverse surfaces. After detachment of the tube feet, the adhesive material stays bound to the substrate as so-called 'footprints'. In the common sea star species Asterias rubens, the adhesive material has been studied extensively and the first sea star footprint protein (Sfp1) has been characterized. We identified Sfp1-like sequences in 17 additional sea star species, representing different taxa and tube foot morphologies, and analysed the evolutionary conservation of this protein. In A. rubens, we confirmed the expression of 34 footprint proteins in the tube foot adhesive epidermis, with 22 being exclusively expressed in secretory cells of the adhesive epidermis and 12 showing an additional expression in the stem epidermis. The sequences were used for BLAST searches in seven asteroid transcriptomes providing a first insight in the conservation of footprint proteins among sea stars. Our results highlighted a high conservation of the large proteins making up the structural core of the footprints, whereas smaller, potential surface-binding proteins might be more variable among sea star species. This article is part of the theme issue 'Transdisciplinary approaches to the study of adhesion and adhesives in biological systems'.

Peripherally inserted central catheter with intracavitary electrocardiogram guidance: Malposition risk factors and indications for post-procedural control.

OBJECTIVES:: To confirm the feasibility of intracavitary electrocardiogram guidance to verify tip's position during insertion of peripherally inserted central catheter and to identify clinical factors or intracavitary electrocardiogram patterns associated with aberrant tip's position. METHODS:: A prospective study was conducted in our university hospital after authorization of the ethics committee. All patients addressed for peripherally inserted central catheter insertion were included and received the insertion using intracavitary electrocardiogram and electromagnetic guidance. Side of insertion and three electrocardiogram factors were collected: visualization of P-wave at baseline (sinusal rhythm), acquisition of the maximal P-wave and the negative deflection. All patients had a systematic post-procedural chest X-ray. One of the investigators assessed all chest X-ray, blinded to the results of intracavitary electrocardiogram, and confirmed whether the tip's position on chest X-ray matched with the intracavitary electrocardiogram information or if the tip was malpositioned on chest X-ray (mismatch with intracavitary electrocardiogram or aberrant position). Factors associated with malposition were described. RESULTS:: From January 2015 to April 2015, 330 patients were eligible, 5 had an uninterpretable chest X-ray, and 14 were non-sinusal at baseline. Our main analysis population included 311 patients. We observed a mismatch between intracavitary electrocardiogram and chest X-ray estimate of the tip's position in 3 cases (1%) and an aberrant tip's position occurred in 3 cases (1%). Incidence of malposition was higher in the group of patients with non-sinusal rhythm (14%) and when the catheter was inserted on the left side (7%). CONCLUSION:: This study confirmed the feasibility of intracavitary electrocardiogram for peripherally inserted central catheter positioning and the limits of chest X-ray. Insertion on left side may represent risk factor for aberrant position but our study lacked power to establish a statistical link.

The structural and chemical basis of temporary adhesion in the sea star Asterina gibbosa.

Background: Marine biological adhesives are a promising source of inspiration for biomedical and industrial applications. Nevertheless, natural adhesives and especially temporary adhesion systems are mostly unexplored. Sea stars are able to repeatedly attach and detach their hydraulic tube feet. This ability is based on a duo-gland system and, upon detachment, the adhesive material stays behind on the substrate as a 'footprint'. In recent years, characterization of sea star temporary adhesion has been focussed on the forcipulatid species Asterias rubens. Results: We investigated the temporary adhesion system in the distantly related valvatid species Asterina gibbosa. The morphology of tube feet was described using histological sections, transmission-, and scanning electron microscopy. Ultrastructural investigations revealed two adhesive gland cell types that both form electron-dense secretory granules with a more lucid outer rim and one de-adhesive gland cell type with homogenous granules. The footprints comprised a meshwork on top of a thin layer. This topography was consistently observed using various methods like scanning electron microscopy, 3D confocal interference microscopy, atomic force microscopy, and light microscopy with crystal violet staining. Additionally, we tested 24 commercially available lectins and two antibodies for their ability to label the adhesive epidermis and footprints. Out of 15 lectins labelling structures in the area of the duo-gland adhesive system, only one also labelled footprints indicating the presence of glycoconjugates with α-linked mannose in the secreted material. Conclusion: Despite the distant relationship between the two sea star species, the morphology of tube feet and topography of footprints in A. gibbosa shared many features with the previously described findings in A. rubens. These similarities might be due to the adaptation to a benthic life on rocky intertidal areas. Lectin- and immuno-labelling indicated similarities but also some differences in adhesive composition between the two species. Further research on the temporary adhesive of A. gibbosa will allow the identification of conserved motifs in sea star adhesion and might facilitate the development of biomimetic, reversible glues.

Correlation between laboratory coagulation testing and thromboelastometry is modified during management of trauma patients.

BACKGROUND: Thromboelastometry (ROTEM, Pentapharm GmbH, Munich, Germany) is increasingly being used to make a diagnosis of coagulopathy and to guide hemostatic therapy (HT). Although ROTEM parameters and standard laboratory test (SLT) correlated well before administration of HT, it is not known if this correlation persists after hemostatic resuscitation. METHODS: A retrospective analysis of prospectively collected data from a trauma registry (2011-2014) was performed. All patients having a ROTEM analysis were included. ROTEM parameters (clotting time and clot amplitude at 5 minutes) were determined after activation with tissue factor (EXTEM) or platelet inhibition with cytochalasin D (FIBTEM). Spearman rank correlation coefficient was calculated for the correlation between SLT and thromboelastometry parameters, and thresholds were determined with receiver operating characteristic (ROC) curve analysis for the diagnosis of an international normalized ratio (INR) greater than 1.5, fibrinogen 1.5 g/L or less, and platelet count of less than 100.10/L. RESULTS: Of the 358 patients included, 533 thromboelastometry results were obtained (335 at admission, 198 during care). Correlation between INR and EXTEM-clotting time was good at admission (r = 0.617) in the whole cohort but decreased in the subgroup of patients having an Injury Severity Score of less than 25 (r = 0.399) or a base excess of less than 6 mmol/L (r = 0.489). During care, correlation was impaired after the administration of fibrinogen concentrates in the whole cohort (r = 0.430), as well as in the subgroup of patients having an Injury Severity Score greater than 24 (r = 0.465). As well, for the diagnosis of increased INR, sensitivity and the area under the ROC curve decreased from 75% and 0.894 (no treatment) to 20% and 0.653 (fibrinogen concentrate). Areas under the ROC curve for the prediction of a fibrinogen or platelet decrease were not significantly altered regardless of the treatment group. CONCLUSIONS: A decrease in the correlation between SLTs and ROTEM parameters was observed at admission or during care, which could be in relation with injury severity, base deficit, or the administration of blood products, particularly fibrinogen concentrate. Further work will be necessary to better understand which tool is the most suitable for guiding HT. LEVEL OF EVIDENCE: Therapeutic study, level IV; diagnostic study, level IV.

Prospective comparison between total sternotomy and ministernotomy for aortic valve replacement.

Ministernotomy (MS) is an alternative for total sternotomy (TS) in aortic valve replacement. We compared these two approaches for results and adverse effects in a prospective study. From January to December 2000, 100 patients who underwent aortic valve replacement were included in two groups of 50 according to the surgical approach that used MS or TS; one senior surgeon performed all cases in each group. Valvular pathologies were either stenosis or insufficiency. Mean age was 63 +/- 14 years in MS, 67 +/- 12 in TS (p = ns). NYHA class was 2.7 +/- 0.5 in MS, 2.8 +/- 0.6 in TS (p = ns). Left ventricular ejection fraction was 58 +/- 12% in MS, 57 +/- 12% in TS (p = ns). There was a significant difference between MS and TS in aortic cross-clamping (66 +/- 14 min vs 48 +/- 9 min) and cardiopulmonary bypass (88 +/- 18 min vs 69 +/- 10 min, p < 0.01), but not in intervention times (2.8 +/- 0.4 hours vs 2.7 +/- 0.4 hours). Mean intensive care stay was reduced in MS (1.7 +/- 1.6 days vs 2.6 +/- 6 days, p < 0.05). Intubation times (12 +/- 7 hours vs 14 +/- 9 hours), 24 hours bleeding (394 +/- 219 mL vs 465 +/- 318), reintervention for hemostasis (4% vs 2%), rhythmic complications (14% vs 14%), and mortality at 1 month (2% vs 2%) were comparable in MS and TS. In aortic valve surgery, ministernotomy is technically more demanding and needs more time. It is as safe and as effective as conventional sternotomy but its eventual benefits, excepting upon cosmesis, are still to be defined.