Morphological and Physical Analysis of Natural Phospholipids-Based Biomembranes

Background: Liposomes are currently an important part of biological, pharmaceutical, medical and nutritional research, as they are considered to be among the most effective carriers for the introduction of various types of bioactive agents into target cells. Scope of Review In this work, we study the lipid organization and mechanical properties of biomembranes made of marine and plant phospholipids. Membranes based on phospholipids extracted from rapeseed and salmon are studied in the form of liposome and as supported lipid bilayer. Dioleylphosphatidylcholine (DOPC) and dipalmitoylphosphatidylcholine (DPPC) are used as references to determine the lipid organization of marine and plant phospholipid based membranes. Atomic force microscopy (AFM) imaging and force spectroscopy measurements are performed to investigate the membranes' topography at the micrometer scale and to determine their mechanical properties. Major Conclusions The mechanical properties of the membranes are correlated to the fatty acid composition, the morphology, the electrophoretic mobility and the membrane fluidity. Thus, soft and homogeneous mechanical properties are evidenced for salmon phospholipids membrane containing various polyunsaturated fatty acids. Besides, phase segregation in rapeseed membrane and more important mechanical properties were emphasized for this type of membranes by contrast to the marine phospholipids based membranes. General Significance This paper provides new information on the nanomechanical and morphological properties of membrane in form of liposome by AFM. The originality of this work is to characterize the physico-chemical properties of the nanoliposome from the natural sources containing various fatty acids and polar head

Etude du comportement superélastique d'un stent en alliage à mémoire de forme. Investigations expérimentales et numériques

Les alliages à mémoire de forme (AMF) sont classiquement utilisés en biomécanique. On s'intéresse ici à prédire le comportement superélastique d'un stent AMF (nickel titane) présentant une géométrie particulière à fils enchevêtrés. Le modèle CAO tridimensionnel réalisé avec Catia V5 est importé dans Abaqus, et une loi de comportement phénoménologique implémentée via la routine UMAT permet de prendre en compte le comportement superélastique. Des tests de compression et de gonflement sont simulés et les résultats comparés avec les investigations expérimentales correspondantes

The SIB Swiss Institute of Bioinformatics' resources: focus on curated databases

The SIB Swiss Institute of Bioinformatics (www.isb-sib.ch) provides world-class bioinformatics databases, software tools, services and training to the international life science community in academia and industry. These solutions allow life scientists to turn the exponentially growing amount of data into knowledge. Here, we provide an overview of SIB's resources and competence areas, with a strong focus on curated databases and SIB's most popular and widely used resources. In particular, SIB's Bioinformatics resource portal ExPASy features over 150 resources, including UniProtKB/Swiss-Prot, ENZYME, PROSITE, neXtProt, STRING, UniCarbKB, SugarBindDB, SwissRegulon, EPD, arrayMap, Bgee, SWISS-MODEL Repository, OMA, OrthoDB and other databases, which are briefly described in this article

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Infected Shoulder Arthroplasty in Patients Younger than 60 Years: Results of a Multicenter Study

Background: Periprosthetic joint infection (PJI) after shoulder arthroplasty remains a significant complication. This study aimed to explore the epidemiology and risk factors of shoulder PJI in patients aged 60 and younger, analyze treatment options, and evaluate outcomes after 1-year follow-up. Methods: In this retrospective multicentric observational study, data from 1404 shoulders in patients under 60 who underwent primary shoulder arthroplasty were analyzed. Patients with PJI and at least 1-year follow-up after infection treatment were included. Results: The study identified 55 shoulders with PJI, resulting in a 2.35% infection rate after primary shoulder arthroplasty in the young population. Male gender and reverse shoulder arthroplasty were risk factors for infection, while previous surgeries did not significantly contribute. The most common causative agents were Cutibacterium acnes and Staphylococcus epidermidis. Open washout had a 52.9% success rate for acute infections, while one-stage and two-stage revisions achieved infection control rates of 91.3% and 85.7%, respectively. Resection arthroplasty had an 81.8% success rate but poorer functional outcomes. Conclusions: PJI following shoulder arthroplasty in young patients is a significant concern. Preoperative planning should be carefully considered to minimize infection risk. Treatment options such as open washout and one-stage and two-stage revisions offer effective infection control and improved functional outcomes. Resection arthroplasty should be reserved for complex cases where reimplantation is not a viable option

Alginate/sodium caseinate aqueous-core capsules: A pH-responsive matrix

International audienceHypothesis: Alginate capsules have several applications. Their functionality depends considerably on their permeability, chemical and mechanical stability. Consequently, the creation of composite system by addition of further components is expected to control mechanical and release properties of alginate capsules. Experiments: Alginate and alginate-sodium caseinate composite liquid-core capsules were prepared by a simple extrusion. The influence of the preparation pH and sodium caseinate concentration on capsules physico-chemical properties was investigated. Findings: Results showed that sodium caseinate influenced significantly capsules properties. As regards to the membrane mechanical stability, composite capsules prepared at pH below the isoelectric point of sodium caseinate exhibited the highest surface Young's modulus, increasing with protein content, explained by potential electrostatic interactions between sodium caseinate amino-groups and alginate carboxylic group. The kinetic of cochineal red A release changed significantly for composite capsules and showed a pH-responsive release. Findings: Sodium caseinate-dye mixture studied by absorbance and fluorescence spectroscopy confirmed complex formation at pH 2 by electrostatic interactions between sodium caseinate tryptophan residues and cochineal red sulfonate-groups. Consequently, the release mechanism was explained by membrane adsorption process. Findings: This global approach is useful to control release mechanism from macro and micro-capsules by incorporating guest molecules which can interact with the entrapped molecule under specific conditions

Glenoid Inclination: Choosing the Transverse Axis Is Critical&mdash;A 3D Automated versus Manually Measured Study

The aim of this study was to evaluate the variation in measured glenoid inclination measurements between each of the most used methods for measuring the scapular transverse axis with computed tomography (CT) scans, and to investigate the underlying causes that explain the differences. Methods: The glenoid center, trigonum and supraspinatus fossa were identified manually by four expert shoulder surgeons on 82 scapulae CT-scans. The transverse axis was generated either from the identified landmarks (Glenoid-Trigonum line (GT-line), Best-Fit Line Fossa (BFLF)) or by an automatic software (Y-axis). An assessment of the interobserver reliability was performed. We compared the measured glenoid inclination when modifying the transverse axis to assess its impact. Results: Glenoid inclination remained stable between 6.3 and 8.5&deg;. The variations occurred significantly when changing the method that determined the transverse axis with a mean biase from &minus;1.7 (BFLF vs. Y-axis) to 0.6 (BFLF vs. GT-line). The Y-axis method showed higher stability to the inclination variation (p = 0.030). 9% of cases presented more than 5&deg; of discrepancies between the methods. The manual methods presented a lower ICC (BFLF = 0.96, GT-line = 0.87) with the widest dispersion. Conclusion: Methods that determine the scapular transverse axis could have a critical impact on the measurement of the glenoid inclination. Despite an overall good concordance, around 10% of cases may provide high discrepancies (&ge;5&deg;) between the methods with a possible impact on surgeon clinical choice. Trigonum should be used with caution as its anatomy is highly variable and more than two single points provide a better interrater concordance. The Y-axis is the most stable referential for the glenoid inclination

Successfully treatment by eribulin in visceral crisis: a case of lymphangitic carcinomatosis from metastatic breast cancer

Abstract Background Metastatic breast cancer (MBC) rest an incurably disease associated with bad prognosis and a median overall survival of 23–31 months. There are several treatment options including chemotherapy and sometimes endocrine therapy. Currently, there is no standard treatment for patients with MBC who have already benefited from anthracyclines and taxanes therapy. Many drugs like capecitabine, eribulin, gemcitabine, vinorelbin and liposomal doxorubicin are conventionally used as monotherapy. One important complication from MBC is life threating visceral crisis that needs a fast-effective treatment. Case presentation We report here a case of an evolution of metastatic breast cancer with lymphangitic carcinomatosis after taxane based chemotherapy and endocrine therapy. This 37-year-old woman was referred to our hospital with complaints of dyspnea and dry cough. There was clinical concern for visceral crisis and a chemotherapy with eribulin was initiated. Pulmonary lymphangitic carcinomatosis disappeared and the patient achieved a good partial response. Conclusion We reported a case of rapid, positive treatment response using eribulin on metastatic breast cancer with visceral crisis and we could quoted others. Therefore, eribulin may be an appropriate chemotherapeutic option in instances requiring rapid symptom control

The dynamics and pH-dependence of Ag43 adhesins’ self-association probed by atomic force spectroscopy

International audienceSelf-associating auto-transporter (SAAT) adhesins are two-domain cell surface proteins involved in bacteria auto-aggregation and biofilm formation. Antigen 43 (Ag43) is a SAAT adhesin commonly found in Escherichia coli whose variant Ag43a has been shown to promote persistence of uropathogenic E. coli within the bladder. The recent resolution of the tri-dimensional structure of the 499 amino-acids' beta-domain in Ag43a has shed light on the possible mechanism governing the self-recognition of SAAT adhesins, in particular the importance of trans-interactions between the L shaped beta-helical scaffold of two alpha-domains of neighboring adhesins. In this study, we use single-molecule force spectroscopy (SMFS) and dynamic force spectroscopy (DFS) to unravel the dynamics of Ag43-self association under various pH and molecular elongation rate conditions that mimic the situations encountered by E. coli in its natural environment. Results evidenced an important stretchability of Ag43alpha with unfolding of sub-domains leading to molecular extension as long as 150 nm. Nanomechanical analysis of molecular stretching data suggested that self-association of Ag43 can lead to the formation of dimers and tetramers driven by rapid and weak cis- as well as slow but strong trans-interaction forces with a magnitude as large as 100-250 pN. The dynamics of cis- and trans-interactions were demonstrated to be strongly influenced by pH and applied shear force, thus suggesting that environmental conditions can modulate Ag43-mediated aggregation of bacteria at the molecular level

AFM images of supported lipid bilayers made of phospholipids from rapeseed mixed with DOPC and DPPC.

<p>Ratios of rapeseed phospholipids, DOPC, and DPPC are respectively 1∶1∶0 (a), 1∶0∶1 (b), 1∶1∶1 (c), 2∶1∶1 (d), 4∶1∶1 (e), and 8∶1∶1 (f).</p