Search results for "Bioengineering"
showing 10 items of 1963 documents
Single Particle Plasmon Sensors as Label-Free Technique To Monitor MinDE Protein Wave Propagation on Membranes.
2016
We use individual gold nanorods as pointlike detectors for the intrinsic dynamics of an oscillating biological system. We chose the pattern forming MinDE protein system from Escherichia coli (E. coli), a prominent example for self-organized chemical oscillations of membrane-associated proteins that are involved in the bacterial cell division process. Similar to surface plasmon resonance (SPR), the gold nanorods report changes in their protein surface coverage without the need for fluorescence labeling, a technique we refer to as NanoSPR. Comparing the dynamics for fluorescence labeled and unlabeled proteins, we find a reduction of the oscillation period by about 20%. The absence of photoble…
The impact of cooking on meat microstructure studied by low field NMR and Neutron Tomography
2017
International audience; We studied the impact of temperature of cooking on meat microstructure. The cooking temperature was verified by calorimetry, showing the disappearance of endothermic peaks when cooking temperature was increased. These observations correspond to the denaturation of different protein fractions at specific temperatures. 1H-low field NMR and neutron tomography were used to further understand the relationship between the observed protein denaturation and changes in meat microstructure after heating. Hahn’s echo and solid echo NMR sequences were applied to observe fast relaxation time corresponding to rigid protons. These protons were found to be associated with pools of p…
Functional Mechanics of a Pectin-Based Pleural Sealant after Lung Injury.
2017
Pleural injury and associated air leaks are a major influence on patient morbidity and healthcare costs after lung surgery. Pectin, a plant-derived heteropolysaccharide, has recently demonstrated potential as an adhesive binding to the glycocalyx of visceral mesothelium. Since bioadhesion is a process likely involving the interpenetration of the pectin-based polymer with the glycocalyx, we predicted that the pectin-based polymer may also be an effective sealant for pleural injury. To explore the potential role of an equal (weight%) mixture of high-methoxyl pectin and carboxymethylcellulose as a pleural sealant, we compared the yield strength of the pectin-based polymer to commonly available…
Endocannabinoid 2-arachidonoylglycerol is elevated in the coronary circulation during acute coronary syndrome
2019
Objectives The endocannabinoid system modulates coronary circulatory function and atherogenesis. The two major endocannabinoids (eCB), 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamide (AEA), are increased in venous blood from patients with coronary artery disease (CAD). However, given their short half-life and their autocrine/paracrine mechanism of action, eCB levels in venous blood samples might not reflect arterial or coronary eCB concentrations. The aim of this cross-sectional study was to identify the local concentration profile of eCB and to detect whether and how this concentration profile changes in CAD and NSTEMI versus patients without CAD. Methods and results 83 patien…
Relation between high levels of myeloperoxidase in the culprit artery and microvascular obstruction, infarct size and reverse remodeling in ST-elevat…
2017
International audience; MAIN OBJECTIVE: To better understand the role of myeloperoxidases (MPO) in microvascular obstruction (MO) phenomenon and infarct size (IS) using cardiac magnetic resonance (CMR) data in patients with acute myocardial infarction (AMI).METHOD: 40 consecutive patients classified according to the median level of MPO in the culprit artery. A CMR study was performed during the week following AMI and at 6 months, with late gadolinium enhancement sequences.RESULTS: Persistent MO was observed in the same proportion (50 vs. 65%, p = 0.728) between the low vs. high MPO group levels. However, the extent of the microvascular obstruction was significantly greater in the high-MPO g…
Structural Heteropolysaccharide Adhesion to the Glycocalyx of Visceral Mesothelium
2018
Bioadhesives are biopolymers with potential applications in wound healing, drug delivery, and tissue engineering. Pectin, a plant-based heteropolysaccharide, has recently demonstrated potential as a mucoadhesive in the gut. Since mucoadhesion is a process likely involving the interpenetration of the pectin polymer with mucin chains, we hypothesized that pectin may also be effective at targeting the glycocalyx of the visceral mesothelium. To explore the potential role of pectin as a mesothelial bioadhesive, we studied the interaction of various pectin formulations with the mesothelium of the lung, liver, bowel, and heart. Tensile strength, peel strength, and shear resistance of the bioadhesi…
Bi-layered polyurethane – Extracellular matrix cardiac patch improves ischemic ventricular wall remodeling in a rat model
2016
As an intervention to abrogate ischemic cardiomyopathy, the concept of applying a temporary, local patch to the surface of the recently infarcted ventricle has been explored from a number of design perspectives. Two important features considered for such a cardiac patch include the provision of appropriate mechanical support and the capacity to influence the remodeling pathway by providing cellular or biomolecule delivery. The objective of this report was to focus on these two features by first evaluating the incorporation of a cardiac extracellular matrix (ECM) component, and second by evaluating the impact of patch anisotropy on the pathological remodeling process initiated by myocardial …
In vitro evaluation of a biomaterial-based anticancer drug delivery system as an alternative to conventional post-surgery bone cancer treatment
2018
Patients diagnosed with osteosarcoma are currently treated with intravenous injections of anticancer agents after tumor resection. However, due to remaining neoplastic cells at the site of tumor removal, cancer recurrence often occurs. Successful bone regeneration combined with the control of residual cancer cells presents a challenge for tissue engineering. Cyclodextrins loaded with chemotherapeutic drugs reversibly release the drugs over time. Hydroxyapatite bone biomaterials coated with doxorubicin-loaded cyclodextrin should release the drug with time after implantation directly at the original tumor site and may be a way to eliminate residual neoplastic cells. In the present study, we h…
Effect of Low-Intensity Pulsed Ultrasound on Osteogenic Human Mesenchymal Stem Cells Commitment in a New Bone Scaffold
2017
Purpose Bone tissue engineering is helpful in finding alternatives to overcome surgery limitations. Bone growth and repair are under the control of biochemical and mechanical signals; therefore, in recent years several approaches to improve bone regeneration have been evaluated. Osteo-inductive biomaterials, stem cells, specific growth factors and biophysical stimuli are among those. The aim of the present study was to evaluate if low-intensity pulsed ultrasound stimulation (LIPUS) treatment would improve the colonization of an MgHA/Coll hybrid composite scaffold by human mesenchymal stem cells (hMSCs) and their osteogenic differentiation. LIPUS stimulation was applied to hMSCs cultured on …
Single nanogranules preserve intracrystalline amorphicity in biominerals.
2015
We revisit the ultrastructural features of different calcareous biominerals and identify remarkable similarities: taxonomically very distant species show a common nanogranular structure, even if different extracellular secretion patterns are employed or calcium carbonate polymorphs formed. By these analyses, we elucidate the locus of the small fraction of intracrystalline organic matrix revealing its intergranular character and localize the intracrystalline amorphous calcium carbonate moiety commonly found in mesocrystalline biominerals and provide a first explanation for the pathway by which it is preserved.