3,203 research outputs found
Direct replacement of antibodies with molecularly imprinted polymer (MIP) nanoparticles in ELISA - development of a novel assay for vancomycin
No full textA simple and straightforward technique for coating microplate wells with molecularly imprinted polymer nanoparticles (nanoMIPs) to develop ELISA type assays is presented here for the first time. NanoMIPs were synthesized by a solid phase approach with immobilized vancomycin (template) and characterized using Biacore 3000, dynamic light scattering and electron microscopy. Immobilization, blocking and washing conditions were optimized in microplate format. The detection of vancomycin was achieved in competitive binding experiments with a HRP-vancomycin conjugate. The assay was capable of measuring vancomycin in buffer and in blood plasma within the range 0.001-70 nM with a detection limit of 0.0025 nM (2.5 pM). The sensitivity of the assay was three orders of magnitude better than a previously described ELISA based on antibodies. In these experiments nanoMIPs have shown high affinity and minimal interference from blood plasma components. Immobilized nanoMIPs were stored for 1 month at room temperature without any detrimental effects to their binding properties. The high affinity of nanoMIPs and the lack of a requirement for cold chain logistics make them an attractive alternative to traditional antibodies used in ELIS
TrkB signaling directs the incorporation of newly generated periglomerular cells in the adult olfactory bulb.
No full textIn the adult rodent brain, the olfactory bulb (OB) is continuously supplied with new neurons which survival critically depends on their successful integration into pre-existing networks. Yet, the extracellular signals that determine the selection which neurons will be ultimately incorporated into these circuits are largely unknown. Here, we show that immature neurons express the catalytic form of the brain-derived neurotrophic factor receptor TrkB [full-length TrkB (TrkB-FL)] only after their arrival in the OB, at the time when inte-gration commences. To unravel the role of TrkB signaling in newborn neurons, we conditionally ablated TrkB-FL in mice via Cre expression in adult neural stem and progenitor cells. TrkB-deficient neurons displayed a marked impairment in dendritic arborization and spine growth. By selectively manipulating the signaling pathways initiated by TrkB in vivo, we identified the transducers Shc/PI3K to be required for dendritic growth, whereas the activation of phospholipase C-was found to be responsible for spine formation. Further-more, long-term genetic fate mapping revealed that TrkB deletion severely compromised the survival of new dopaminergic neurons, leading to a substantial reduction in the overall number of adult-generated periglomerular cells (PGCs), but not of granule cells (GCs). Surprisingly, this loss of dopaminergic PGCs was mirrored by a corresponding increase in the number of calretinin PGCs, suggesting that distinct subsets of adult-born PGCs may respond differentially to common extracellular signals. Thus, our results identify TrkB signaling to be essential for balancing the incorporation of defined classes of adult-born PGCs and not GCs, reflecting their different mode of integration in the OB. © 2013 the authors
Riorganizzazione della funzione manuale in soggetti con lesione precoce dei sistemi motori e sensoriali
No full textRiorganizzazione della funzione manuale in soggetti con lesione precoce dei sistemi motori e sensorial
Omega-3 fatty acid and antioxidant enriched liposomes for nasal administration of anti-Alzheimer drugs
No full textThe purpose of this work was the formulation of
liposomes for nasal administration of tacrine·HCl. This
route has many advantages, in fact it is possible to convey
the drug directly to the CNS, through the olfactory bulb.
Part of tacrine administered can also be absorbed into the
systemic circulation avoiding hepatic first pass effect.
Liposomes were formulated with ingredients that have a
beneficial effect against the disease. In particular, the
cholesterol was replaced with α-tocopherol, and
phospholipids were enriched with polyunsaturated fatty
acids (DHA, EPA α-linolenic acid). This formulative
approach allowed us to obtain 100% active liposomes
against symptoms of Alzheimer's disease
Hormesis and cardioprotection
No full textOxidative stress has been reported to play a causative role in cardiovascular diseases. Although reactive oxygen species (ROS) are known to enhance myocardial ischemia-reperfusion injury (Morihira et al, 2005), it has been demonstrated that a short-timed ischemia, also called preconditioning, may exert a protective role, preventing thus from a subsequent prolonged stress. Several factors have been reported to mediate preconditioning mechanism, such as blockade of reduction in mitochondrial membrane potential or modulation of multiple genes and signalling pathways (Tang et al, 2005). Anyway, the apparent paradox of preconditioning is strictly connected with a biphasic process known as “hormesis”. Hormesis is a dose-response phenomenon characterized by a low-dose stimulation and a high-dose inhibition: as a consequence, the same stressor that at higher doses appears toxic, at lower ones leads to beneficial effects (Calabrese and Baldwin, 2002). In this way, preconditioning can be considered as an hormetic response as well. The aim of this work is to investigate the probable protective role of preconditioning on oxidative stress in cultured cardiomyocytes and its effects on antioxidant enzymatic machinery, in order to enlighten the mechanism of protection and the targets involved. In our study we used H2O2 as stressor, as it is well documented that this molecule is capable of adaptative responses similar to those induced by ischemic preconditioning.
Materials and methods. Cultured rat neonatal cardiomyocytes were prepared and grown until confluence as previously reported (Hrelia et al., 2002). Preconditiong was simulated exposing the cells to 100 μM H2O2 for ten minutes and, 24 hours later, oxidative stress was induced with 100 μM H2O2 for 30 minutes. Cell viability was evaluated by MTT assay. Apoptosis and necrosis analysis was assessed by cytofluorimetric assay using Guava Nexin Assay (Guava Technologies). Enzymatic activities of glutathione reductase (GR), glutathione-S-transferase (GST), glutathione peroxidase (GPX), thioredoxin reductase (TR), NAD(P)H:quinone oxidoreductase 1 (NQO1), catalase (CAT) and superoxide dismutase (SOD) were determined by spectrophotometric methods.
Results and discussion. MTT results indicate a significant protective effect of preconditioning against oxidative stress, preconditioning with 100 μM H2O2 led to a complete protection against subsequent peroxide induced-injury. In agreement with MTT data, cytofluorimetric assay showed that preconditioning was able to reduce necrotic and apoptotic populations and increased viable cells in comparison to oxidative stress only. Preconditioning was able to increase GR, NQO1, TR and CAT activities, while it did not influence GPX, GST, and SOD activities. So the preconditioning protective effect may be ascribed to an increased cell ability to detoxify ROS by increasing the activities of fundamental antioxidant/phase II enzymes. As all these enzymes are regulated through the Keap1-Nrf2-antioxidant responsive element signalling pathway, their unlinked regulation underpins the hypothesis that preconditioning could modulate these enzymes through different mechanisms.
Supported by Fondazione del Monte di Bologna e Ravenna
Molecular mechanisms of hydrogen peroxide preconditioning in cultured cardiomyocytes
No full textIn cardiac cells a short-timed stress, also called preconditioning (PR), may exert a protective role against a subsequent prolonged stress. In this study, we explored whether H2O2-PR protects against H2O2-induced oxidative stress in cardiac cells and the roles of phase II enzymes and MAPK signaling pathways in this adaptive protection. Primary cultures of cardiomyocytes were grown at confluence. PR was simulated with 1-100 μM H2O2 for 10 min, while oxidative stress was induced by 100 μM H2O2 for 30 min. Cell viability was evaluated by MTT and cytofluorimetric assays. Enzyme activities were determined by spectrophotometric methods. Phosphorylation of p38, Akt and ERK1/2 was analyzed by immunoblotting. MTT and cytofluorimetric analysis indicate a significant protective effect of PR against oxidative stress. PR was able to modulate the activities of different phase II enzymes and to increase the phosphorylation of ERK1/2, p38 and Akt protein kinases. Specific kinase inhibitors demonstrated that only p38 and Akt are involved in the protection elicited by PR
Coaching early career teachers in urban elementary schools: A mixed method study
No full textCoaching for urban early career teachers (ECTs) offers promise and aligns with features of effective professional development to support the implementation of evidence-based practices. However, the functional components and key elements of coaching and coach supervision are not well specified in the literature. The goal of the current study was to examine adherence and feasibility of a coaching intervention designed to provide urban ECTs with concentrated support in classroom management and engaging learners—two instructional domains that are robust predictors of attrition (Ingersoll and Strong in Rev Educ Res 81:201–233, 2011). Coaches (n = 6) worked with ECTs (n = 15) in three urban, high-poverty elementary schools during the 2-year intervention. A mixed-method design was employed, such that qualitative data (i.e., semi-structured interviews) and quantitative data (i.e., adherence measures) were collected concurrently, remained independent during analyses, and were integrated during interpretation (Creswell and Clark in Designing and conducting mixed methods research. Sage, Thousand Oaks, 2007). Findings revealed that ECTs generally received the intended frequency and duration of coaching but with fewer opportunities for post-conferences. Coach supervision, on average, was delivered with intended frequency, with variability across coaches. Thematic analyses highlighted coach provision of emotional and instrumental support, emphasized consistent coaching as critical, and that time was a significant barrier to ECT participation in coaching. Supervision promoted social support among coaches and provided opportunities to adapt the model to ECT needs.Peer reviewe
Communautés et écriture en ligne. Histoire, devenir, un dialogue
No full textIn this interview, Elisa Bricco talks to writer Benoît Vincent about
the transformations that have taken place over the last twenty years
as a result of the technological turn in literary production. We look
at the repercussions of technology’s hold over literary production, and
in particular at the development of the notion of author in the context
of collective writing. The example of the General Instin project will
be used to highlight some of the issues raised by digital technology in
relation to the production of literary texts.Dans cet entretien, Elisa Bricco discute avec l’écrivain Benoît Vincent
sur les transformations qui sont survenues dans les vingt dernières
années à cause du tournant technologique de la production littéraire. On
s’interroge sur les répercussions de l’emprise de la technologie sur le
faire littéraire et notamment sur le développement de la notion d’auteur
dans le contexte de l’écriture collective. L’exemple du projet Général
Instin servira pour mettre en lumières quelques enjeux du numérique
par rapport à la production de textes littéraires
Communautés et écriture en ligne. Histoire, devenir, un dialogue
No full textIn this interview, Elisa Bricco talks to writer Benoît Vincent about the transformations that have taken place over the last twenty years as a result of the technological turn in literary production. We look at the repercussions of technology’s hold over literary production, and in particular at the development of the notion of author in the context of collective writing. The example of the Général Instin project will be used to highlight some of the issues raised by digital technology in relation to the production of literary texts.Dans cet entretien, Elisa Bricco discute avec l’écrivain Benoît Vincent sur les transformations qui sont survenues dans les vingt dernières années à cause du tournant technologique de la production littéraire. On s’interroge sur les répercussions de l’emprise de la technologie sur le faire littéraire et notamment sur le développement de la notion d’auteur dans le contexte de l’écriture collective. L’exemple du projet Général Instin servira pour mettre en lumières quelques enjeux du numérique par rapport à la production de textes littéraires
Sulforaphane as an antiapoptotic nutraceutical in cardiac cells
No full textCardiomyocyte loss through apoptosis has been reported in a variety of cardiovascular diseases. Being a highly regulated cell death program its inhibition is cardioprotective. We previously demonstrated that sulforaphane (SF), present in many Cruciferous vegetables, boosts cell defence system acting as an indirect antioxidant. The aim of this study was to evaluate SF ability to modulate pro and anti-apoptotic proteins resulting in the inhibition of H2O2-induced apoptosis. SF treatment was able to protect cells against oxidative damage increasing cell viability, and decreasing apoptosis markers like DNA fragmentation and PS exposure. Accordingly, SF reduced bax translocation to mitochondria, cytochrome C release and caspase 3 activation in comparison to untreated cells. Specific protein kinases inhibitors revealed that SF protection is mainly mediated by Akt activation. Taken together these results show that a reduction in apoptotic cell death contributes to cardioprotection, suggesting SF as a promising nutraceutical in the prevention of oxidative stress related cardiac diseases
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