Search results for "TRID"
showing 10 items of 753 documents
Factores radiológicos predictivos de accesibilidad quirúrgica a la fosa pterigopalatina
2020
La fosa pterigopalatina es una pequeña región anatómica con forma de pirámide invertida, localizada a caballo entre la base del cráneo y el macizo facial. Es un espacio pequeño y estrecho, estructuralmente complicado y de difícil accesibilidad quirúrgica. En la fosa se aloja el ganglio esfenopalatino, que está implicado en una amplia variedad de enfermedades relacionadas con el dolor facial de origen neurovegetativo, como la cefalea en racimos. La reciente aparición de técnicas basadas en la neuromodulación del ganglio esfenopalatino para el tratamiento de cefaleas en racimo refractarias hace imprescindible profundizar en el conocimiento de la fosa pterigopalatina y de sus vías de acceso. E…
Defects in III-N LEDs: experimental identification and impact on electro-optical characteristics
2022
III-N light-emitting-diodes (LEDs) are subject of intense investigations, thanks to their high efficiency and great reliability. The quality of the semiconductor material has a significant impact on the electro-optical performance of LEDs: for this reason, a detailed characterization of defect properties and the modeling of the impact of defects on device performance are of fundamental importance. This presentation addresses this issue, by discussing a set of recent case studies on the topic; specifically, we focus on the experimental characterization of defects, and on the modeling of their impact on the electro-optical characteristics of the devices.
Rho GTPases Are Involved in the Regulation of NF-κB by Genotoxic Stress
2001
A common cellular response to genotoxic agents and inflammatory cytokines is the activation of NF-kappaB. Here, we addressed the question of whether small GTPases of the Rho family are involved in the stimulation of NF-kappaB signaling by genotoxic agents or TNFalpha in HeLa cells. Inhibition of isoprenylation of Rho proteins by use of the HMG-CoA reductase inhibitor lovastatin attenuated UV-, doxorubicin-, and TNFalpha-induced degradation of IkappaBalpha as well as drug-stimulated DNA binding activity of NF-kappaB. Furthermore, NF-kappaB-regulated gene expression stimulated by either UV irradiation or treatment with TNFalpha was abrogated by lovastatin pretreatment. This indicates that iso…
Delivery of proteins into living cells by reversible membrane permeabilization with streptolysin-O
2001
The pore-forming toxin streptolysin O (SLO) can be used to reversibly permeabilize adherent and nonadherent cells, allowing delivery of molecules with up to 100 kDa mass to the cytosol. Using FITC-labeled albumin, 10 5 –10 6 molecules were estimated to be entrapped per cell. Repair of toxin lesions depended on Ca 2+ -calmodulin and on intact microtubules, but was not sensitive to actin disruption or to inhibition of protein synthesis. Resealed cells were viable for days and retained the capacity to endocytose and to proliferate. The active domains of large clostridial toxins were introduced into three different cell lines. The domains were derived from Clostridium difficile B-toxin and Clo…
Inhibition of small G proteins of the Rho family by statins orClostridium difficiletoxin B enhances cytokine-mediated induction of NO synthase II
2000
In order to investigate the involvement of Ras and/or Rho proteins in the induction of the inducible isoform of nitric oxide synthase (NOS II) we used HMG-CoA reductase inhibitors (statins) and Clostridium difficile toxin B (TcdB) as pharmacological tools. Statins indirectly inhibit small G proteins by preventing their essential farnesylation (Ras) and/or geranylgeranylation (Rho). In contrast, TcdB is a glucosyltransferase and inactivates Rho-proteins directly. Human A549/8- and DLD-1 cells as well as murine 3T3 fibroblasts were preincubated for 18 h with statins (1–100 μM) or TcdB (0.01–10 ng ml−1). Then NOS II expression was induced by cytokines. NOS II mRNA was measured after 4–8 h by R…
Activation of astroglial phospholipase D activity by phorbol ester involves ARF and Rho proteins.
2000
Primary cultures of rat cortical astrocytes express phospholipase D (PLD) isoforms 1 and 2 as determined by RT-PCR and Western blot. Basal PLD activity was strongly (10-fold) increased by 4beta-phorbol-12beta,13alpha-dibutyrate (PDB) (EC(50): 56 nM), an effect which was inhibited by Ro 31-8220 (0.1-1 microM), an inhibitor of protein kinase C (PKC), and by brefeldin A (10-100 microg/ml), an inhibitor of ADP-ribosylating factor (ARF) activation. Pretreatment of the cultures with Clostridium difficile toxin B-10463 (0.1-1 ng/ml), which inactivates small G proteins of the Rho family, led to a breakdown of the astroglial cytoskeleton; concomitantly, PLD activation by PDB was reduced by up to 50%…
Inhibition of Protein Isoprenylation Impairs Rho-Regulated Early Cellular Response to Genotoxic Stress
2000
Activation of c-Jun N-terminal kinases (JNKs) and nuclear factor-kappaB (NF-kappaB) are early cellular responses to genotoxic stress involved in the regulation of gene expression. Pretreatment of cells with the hydroxymethyl glutaryl-CoA reductase inhibitor lovastatin blocked stimulation of JNK1 activity by UV irradiation and by treatment with the alkylating compound methyl methanesulfonate but did not affect activation of extracellular signal-regulated kinase 2 by UV light. Lovastatin also attenuated UV-induced degradation of the NF-kappaB inhibitor IkappaBalpha. The effects of lovastatin on UV-triggered stimulation of JNK1 as well as on IkappaBalpha degradation were reverted by cotreatmen…
Clostridium difficile Induced Inflammasome Activation and Coagulation Derangements
2022
C. difficile enterocolitis (CDAC) is the most common hospital infection, burdened by an increased incidence of coagulation-related complications such as deep vein thrombosis (DVT) and disseminated intravascular coagulation (DIC) as well as a significant sepsis-related mortality. In this review, we analyzed the available data concerning the correlation between coagulation complications related to C. difficile infection (CDI) and inflammasome activation, in particular the pyrin-dependent one. The little but solid available preclinical and clinical evidence shows that inflammasome activation increases the risk of venous thromboembolism (VTE). As proof of this, it has been observed that in vitr…
IMEX schemes for pricing options under jump–diffusion models
2014
We propose families of IMEX time discretization schemes for the partial integro-differential equation derived for the pricing of options under a jump-diffusion process. The schemes include the families of IMEX-midpoint, IMEX-CNAB and IMEX-BDF2 schemes. Each family is defined by a convex combination parameter [email protected]?[0,1], which divides the zeroth-order term due to the jumps between the implicit and explicit parts in the time discretization. These IMEX schemes lead to tridiagonal systems, which can be solved extremely efficiently. The schemes are studied through Fourier stability analysis and numerical experiments. It is found that, under suitable assumptions and time step restric…
CCDC 1020496: Experimental Crystal Structure Determination
2014
Related Article: Huayan Yang , Yu Wang , Juanzhu Yan , Xi Chen , Xin Zhang , Hannu Häkkinen , and Nanfeng Zheng|2014|J.Am.Chem.Soc.|136|7197|doi:10.1021/ja501811j