708 research outputs found
Nuclear accessibility of β-actin mRNA is measured by 3D single-molecule real-time tracking
Imaging single proteins or RNAs allows direct visualization of the inner workings of the cell. Typically, three-dimensional (3D) images are acquired by sequentially capturing a series of 2D sections. The time required to step through the sample often impedes imaging of large numbers of rapidly moving molecules. Here we applied multifocus microscopy (MFM) to instantaneously capture 3D single-molecule real-time images in live cells, visualizing cell nuclei at 10 volumes per second. We developed image analysis techniques to analyze messenger RNA (mRNA) diffusion in the entire volume of the nucleus. Combining MFM with precise registration between fluorescently labeled mRNA, nuclear pore complexes, and chromatin, we obtained globally optimal image alignment within 80-nm precision using transformation models. We show that {beta}-actin mRNAs freely access the entire nucleus and fewer than 60% of mRNAs are more than 0.5 {my}m away from a nuclear pore, and we do so for the first time accounting for spatial inhomogeneity of nuclear organization
Meeting report: International workshop on implementation of biowaivers based on the biopharmaceutics classification system (BCS)
Even though the pivotal article stating the theoretical basis for a biopharmaceutics drug classification (1) was published almost 20 years ago, the extension of BCS-based biowaiver decisions to drugs belonging to BCS classes other than those showing high solubility and high permeability has not yet reached a consensus among regulators, industrial scientists, and academics. Also, within some jurisdictions, BCS principles have not yet been incorporated into legal frameworks and thus have not been used to allow science- and risk-based regulatory flexibility.
This report provides a brief description of the presentations from the International Workshop on Implementation of Biowaivers based on the BCS in Buenos Aires, Argentina, that took place on March 5–6, 2015.
The meeting was cosponsored by National University of La Plata, Confederación Farmacéutica Argentina, International Pharmaceutical Federation (FIP), and the American Association of Pharmaceutical Scientists (AAPS).
The main objectives of the meeting were to describe the state of the art with respect to in vitro and in silico tools to support waiving in vivo bioequivalence studies and to foster discussion about implementing BCS-based biowaiver decisions to support generic drug registration in South America. Two hundred and fifteen scientists from universities, the pharmaceutical industry, and regulatory authorities took part in this meetingFacultad de Ciencias Exacta
Meeting report: International workshop on implementation of biowaivers based on the biopharmaceutics classification system (BCS)
Even though the pivotal article stating the theoretical basis for a biopharmaceutics drug classification (1) was published almost 20 years ago, the extension of BCS-based biowaiver decisions to drugs belonging to BCS classes other than those showing high solubility and high permeability has not yet reached a consensus among regulators, industrial scientists, and academics. Also, within some jurisdictions, BCS principles have not yet been incorporated into legal frameworks and thus have not been used to allow science- and risk-based regulatory flexibility.
This report provides a brief description of the presentations from the International Workshop on Implementation of Biowaivers based on the BCS in Buenos Aires, Argentina, that took place on March 5–6, 2015.
The meeting was cosponsored by National University of La Plata, Confederación Farmacéutica Argentina, International Pharmaceutical Federation (FIP), and the American Association of Pharmaceutical Scientists (AAPS).
The main objectives of the meeting were to describe the state of the art with respect to in vitro and in silico tools to support waiving in vivo bioequivalence studies and to foster discussion about implementing BCS-based biowaiver decisions to support generic drug registration in South America. Two hundred and fifteen scientists from universities, the pharmaceutical industry, and regulatory authorities took part in this meetingFacultad de Ciencias Exacta
Cooling process for inelastic Boltzmann equations for hard spheres, Part II: Self-similar solutions and tail behavior
We consider the spatially homogeneous Boltzmann equation for inelastic hard
spheres, in the framework of so-called constant normal restitution
coefficients. We prove the existence of self-similar solutions, and we give
pointwise estimates on their tail. We also give general estimates on the tail
and the regularity of generic solutions. In particular we prove Haff 's law on
the rate of decay of temperature, as well as the algebraic decay of
singularities. The proofs are based on the regularity study of a rescaled
problem, with the help of the regularity properties of the gain part of the
Boltzmann collision integral, well-known in the elastic case, and which are
extended here in the context of granular gases.Comment: 41 page
Biowaiver Monographs for Immediate‐Release Solid Oral Dosage Forms: Codeine Phosphate
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106898/1/jps23977.pd
Toward Enriched Conceptions of Work Learning: Participation, Expansion, and Translation Among Individuals With/In Activity
Despite the long recognition in HRD theory that learning is socially and materially situated in activity and relations, HRD literature indicates a continuing strong emphasis on individualistic theories representing learning as knowledge acquisition or individual development. It is argued here that understandings of work learning within HRD theory can be fruitfully enriched by more fully incorporating practice-based perspectives. Three contemporary theories that analyse learning as a relation of individuals with/in activity have been selected for discussion here: the participational perspective of situated cognition, the notion of expansion from cultural-historical activity theory, and the constructs of translation and mobilization presented by actor-network theory. While these are not particularly new to HRD, the contribution of this discussion is to bring together these theories, along with published empirical workplace research based on them, to highlight selected dynamics that may be useful tools for HRD theory development. One element in particular is read across the three theories: the dialectic of ‘flying’ and ‘grounding’, or lines of discontinuity and continuity characterising work learning. The argument is theory-driven, drawing from HRD literature of work learning and practice-based theories of social activity and knowledge production
Meeting report: International workshop on implementation of biowaivers based on the biopharmaceutics classification system (BCS)
Even though the pivotal article stating the theoretical basis for a biopharmaceutics drug classification (1) was published almost 20 years ago, the extension of BCS-based biowaiver decisions to drugs belonging to BCS classes other than those showing high solubility and high permeability has not yet reached a consensus among regulators, industrial scientists, and academics. Also, within some jurisdictions, BCS principles have not yet been incorporated into legal frameworks and thus have not been used to allow science- and risk-based regulatory flexibility.
This report provides a brief description of the presentations from the International Workshop on Implementation of Biowaivers based on the BCS in Buenos Aires, Argentina, that took place on March 5–6, 2015.
The meeting was cosponsored by National University of La Plata, Confederación Farmacéutica Argentina, International Pharmaceutical Federation (FIP), and the American Association of Pharmaceutical Scientists (AAPS).
The main objectives of the meeting were to describe the state of the art with respect to in vitro and in silico tools to support waiving in vivo bioequivalence studies and to foster discussion about implementing BCS-based biowaiver decisions to support generic drug registration in South America. Two hundred and fifteen scientists from universities, the pharmaceutical industry, and regulatory authorities took part in this meetingFacultad de Ciencias Exacta
Guidance on the use of bisphosphonates in solid tumours: recommendations of an international expert panel
Bisphosphonates (BP) prevent, reduce, and delay cancer-related skeletal complications in patients, and have substantially decreased the prevalence of such events since their introduction. Today, a broad range of BP with differences in potency, efficacy, dosing, and administration as well as approved indications is available. In addition, results of clinical trials investigating the efficacy of BP in cancer treatment-induced bone loss (CTIBL) have been recently published. The purpose of this paper is to review the current evidence on the use of BP in solid tumours and provide clinical recommendations. An interdisciplinary expert panel of clinical oncologists and of specialists in metabolic bone diseases assessed the widespread evidence and information on the efficacy of BP in the metastatic and nonmetastatic setting, as well as ongoing research on the adjuvant use of BP. Based on available evidence, the panel recommends amino-bisphosphonates for patients with metastatic bone disease from breast cancer and zoledronic acid for patients with other solid tumours as primary disease. Dosing of BP should follow approved indications with adjustments if necessary. While i.v. administration is most often preferable, oral administration (clodronate, IBA) may be considered for breast cancer patients who cannot or do not need to attend regular hospital care. Early-stage cancer patients at risk of developing CTIBL should be considered for preventative BP treatment. The strongest evidence in this setting is now available for ZOL. Overall, BP are well-tolerated, and most common adverse events are influenza-like syndrome, arthralgia, and when used orally, gastrointestinal symptoms. The dose of BP may need to be adapted to renal function and initial creatinine clearance calculation is mandatory according to the panel for use of any BP. Subsequent monitoring is recommended for ZOL and PAM, as described by the regulatory authority guidelines. Patients scheduled to receive BP (mainly every 3-4 weeks i.v.) should have a dental examination and be advised on appropriate measures for reducing the risk of jaw osteonecrosis. BP are well established as supportive therapy to reduce the frequency and severity of skeletal complications in patients with bone metastases from different cancer
AMPA Receptor Activation Causes Silencing of AMPA Receptor-Mediated Synaptic Transmission in the Developing Hippocampus
Agonist-induced internalization of transmembrane receptors is a widespread biological phenomenon that also may serve as a mechanism for synaptic plasticity. Here we show that the agonist AMPA causes a depression of AMPA receptor (AMPAR) signaling at glutamate synapses in the CA1 region of the hippocampus in slices from developing, but not from mature, rats. This developmentally restricted agonist-induced synaptic depression is expressed as a total loss of AMPAR signaling, without affecting NMDA receptor (NMDAR) signaling, in a large proportion of the developing synapses, thus creating AMPAR silent synapses. The AMPA-induced AMPAR silencing is induced independently of activation of mGluRs and NMDARs, and it mimics and occludes stimulus-induced depression, suggesting that this latter form of synaptic plasticity is expressed as agonist-induced removal of AMPARs. Induction of long-term potentiation (LTP) rendered the developing synapses resistant to the AMPA-induced depression, indicating that LTP contributes to the maturation-related increased stability of these synapses. Our study shows that agonist binding to AMPARs is a sufficient triggering stimulus for the creation of AMPAR silent synapses at developing glutamate synapses
Astrocyte-mediated short-term synaptic depression in the rat hippocampal CA1 area: two modes of decreasing release probability
<p>Abstract</p> <p>Background</p> <p>Synaptic burst activation feeds back as a short-term depression of release probability at hippocampal CA3-CA1 synapses. This short-term synaptic plasticity requires functional astrocytes and it affects both the recently active (< 1 s) synapses (post-burst depression) as well as inactive neighboring synapses (transient heterosynaptic depression). The aim of this study was to investigate and compare the components contributing to the depression of release probability in these two different scenarios.</p> <p>Results</p> <p>When tested using paired-pulses, following a period of inactivity, the transient heterosynaptic depression was expressed as a reduction in the response to only the first pulse, whereas the response to the second pulse was unaffected. This selective depression of only the first response in a high-frequency burst was shared by the homosynaptic post-burst depression, but it was partially counteracted by augmentation at these recently active synapses. In addition, the expression of the homosynaptic post-burst depression included an astrocyte-mediated reduction of the pool of release-ready primed vesicles.</p> <p>Conclusions</p> <p>Our results suggest that activated astrocytes depress the release probability via two different mechanisms; by depression of vesicular release probability only at inactive synapses and by imposing a delay in the recovery of the primed pool of vesicles following depletion. These mechanisms restrict the expression of the astrocyte-mediated depression to temporal windows that are typical for synaptic burst activity.</p
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