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Biochemical Properties of Human D-Amino Acid Oxidase
2017
D-amino acid oxidase catalyzes the oxidative deamination of D-amino acids. In the brain, the NMDA receptor coagonist D-serine has been proposed as its physiological substrate. In order to shed light on the mechanisms regulating D-serine concentration at the cellular level, we biochemically characterized human DAAO (hDAAO) in greater depth. In addition to clarify the physical-chemical properties of the enzyme, we demonstrated that divalent ions and nucleotides do not affect flavoenzyme function. Moreover, the definition of hDAAO substrate specificity demonstrated that D-cysteine is the best substrate, which made it possible to propose it as a putative physiological substrate in selected tiss…
A Perspective : Active Role of Lipids in Neurotransmitter Dynamics
2019
AbstractSynaptic neurotransmission is generally considered as a function of membrane-embedded receptors and ion channels in response to the neurotransmitter (NT) release and binding. This perspective aims to widen the protein-centric view by including another vital component—the synaptic membrane—in the discussion. A vast set of atomistic molecular dynamics simulations and biophysical experiments indicate that NTs are divided into membrane-binding and membrane-nonbinding categories. The binary choice takes place at the water-membrane interface and follows closely the positioning of the receptors’ binding sites in relation to the membrane. Accordingly, when a lipophilic NT is on route to a m…
Local complications associated with labial salivary gland biopsy for diagnosis of Sjögren?s Syndrome : a retrospective cohort study
2019
Background To describe local or systemic complications related to the labial salivary glands biopsy (LSGB) used as diagnostic tool for the diagnosis of Sjogren's Syndrome (SS). Material and methods Clinical databases from a cohort of patients, who underwent LSGB with provisional clinical diagnosis of Sjogren's Syndrome, were retrospectively reviewed. Pain, assessed by registering the intake of analgesic drugs in the first week following the biopsy, and any further relevant clinical information regarding complications after biopsy were recorded. Results 50 patients received LSGB. 10 of them (9 women and 1 man) showed histopathological findings compatible with SS. Ten patient (20%) receiving …
The effects of fractional CO2 laser, Nano-hydroxyapatite and MI paste on mechanical properties of bovine enamel after bleaching
2017
Background This study investigated the effect of post bleaching treatments to the change of enamel elastic modulus and microhardness after dental bleaching in- vitro. Material and Methods Fifty bovine incisor slab were randomly assigned into five groups (n=10). The samples were bleached for three times; 20 minutes each time, by 40% hydrogen peroxide. Next it was applied fractional CO2 laser for two minutes, Nano- hydroxy apatite (N-HA) and MI-paste for 7 days and 2 minutes per day. The sound enamel and bleached teeth without post treatment remained as control groups. The elastic modulus and microhardness were measured at three times; 24 hours, 1 and 2 months. Data were statistically analyze…
A Microscopic Description of SARS-CoV-2 Main Protease Inhibition with Michael Acceptors. Strategies for Improving Inhibitors Design
2020
The irreversible inhibition of the main protease of SARS-CoV-2 by a Michael acceptor known as N3 has been investigated using multiscale methods. The noncovalent enzyme–inhibitor complex was simulated using classical molecular dynamics techniques and the pose of the inhibitor in the active site was compared to that of the natural substrate, a peptide containing the Gln–Ser scissile bond. The formation of the covalent enzyme–inhibitor complex was then simulated using hybrid QM/MM free energy methods. After binding, the reaction mechanism was found to be composed of two steps: (i) the activation of the catalytic dyad (Cys145 and His41) to form an ion pair and (ii) a Michael addition where the …
Autoradiographic imaging of altered synaptic αβγ2 and extrasynaptic αβ GABAA receptors in a genetic mouse model of anxiety
2004
Abstract To image the possible alterations in brain regional GABAA receptor subtype properties in a genetic animal model of human anxiety, mice heterozygous for the deletion of GABAA receptor γ2 subunit (γ2+/−) were studied using ligand autoradiographic assays on brain cryostat sections. The [ 35 S ]TBPS binding assay was designed to reveal impaired GABA and channel site coupling shown to be more prominent in recombinant α1/6β3 than in α1/2β3γ2 or β2 subunit-containing GABAA receptors expressed in HEK 293 cells. Increased GABA-insensitive [ 35 S ]TBPS binding in the γ2+/− mouse brains was evident in the cerebral cortex and in subcortical regions, the alterations being regionally similar to …
Are we correctly measuring the rotational viscosity of heterogeneous bituminous binders?
2020
Modified bituminous binders allow asphalt technologists to design asphalt mixtures with superior performance. However, several recent studies highlighted that due to the complexity of these material, their characterisation can be challenging since common procedures used to characterise neat bitumen might not be adequate. For instance, during high temperature rotational viscosity testing of recycled tyre rubber modified binders (RTR-MB), a number of changes may occur to the sample leading to the here-defined sample stability which in turn provides misleading results. In this study the authors want to first provide a deeper understanding of this phenomenon by a numerical analysis using a besp…
Reclaimed asphalt binders and mortars fatigue behaviour
2017
Fatigue cracking is one of the most important failure mechanisms occurring in asphalt pavements, especially when mixtures incorporate considerable amount of rReclaimed asphalt pavement (RAP). In fact, aged binders contained in RAP generally make asphalt more brittle and specifically reduce fatigue resistance of the resulting asphalt mixtures. Binders and mortars play a key role in this phenomenon, considering fatigue cracking usually starts within these asphalt components. However, performance-related tests and specifications commonly regard binders and there are no sound methodologies allowing the use of mortars to predicting fatigue performance of asphalts containing RAP. For this reason,…
L'accroissement de l'effet de l'origine sociale sur la performance scolaire : par où est-il passé ?
2017
International audience; L'ampleur considérable des inégalités sociales de performances scolaires interroge fortement l'équité de l'école. Nous cherchons, dans ce travail, à mettre en lumière les facteurs de l'accroissement récent de ces inégalités par le biais d'indicateurs disponibles dans les données des enquêtes PISA (2003 et 2012). Nous étudions d'abord l'évolution des différentes composantes de l'indicateur multicritère par lequel l'OCDE mesure le plus souvent le milieu social. Ensuite, nous modélisons, par une analyse en pistes causales, la décomposition de l'effet du statut professionnel des parents sur les performances afin de saisir par quoi il transite. Sont mobilisés des facteurs…