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Search Results: 1 - 10 of 197167 matches for " G. Martinez-Sanchez "
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The highly selective cyclooxygenase-2 inhibitor DFU is neuroprotective when given several hours after transient cerebral ischemia in gerbils
E. Candelario-Jalil,D. Alvarez,J. M. Castaneda,S. M. Al-Dalain,G. Martinez-Sanchez,N. Merino,O. S. Leon
Quantitative Biology , 2007,
Abstract: Several studies suggest that cyclooxygenase-2 contributes to the delayed progression of ischemic brain damage. In this study we examined whether the highly selective cyclooxygenase-2 inhibitor DFU reduces neuronal damage when administered several hours after 5 min of transient forebrain ischemia in gerbils. The extent of ischemic injury was assessed behaviorally by measuring the increases in locomotor activity and by histopathological evaluation of the extent of CA1 hippocampal pyramidal cell injury 7 days after ischemia. DFU treatment (10 mg/kg, p.o.) significantly reduced hippocampal neuronal damage even if the treatment is delayed until 12 h after ischemia. These results suggest that selective cyclooxygenase-2 inhibitors may be a valuable therapeutic strategy for ischemic brain injury.
Neuroprotective efficacy of nimesulide against hippocampal neuronal damage following transient forebrain ischemia
E. Candelario-Jalil,D. Alvarez,A. Gonzalez-Falcon,M. Garcia-Cabrera,G. Martinez-Sanchez,N. Merino,A. Giuliani,O. S. Leon
Quantitative Biology , 2007,
Abstract: Cyclooxygenase-2 is involved in the inflammatory component of the ischemic cascade, playing an important role in the delayed progression of the brain damage. The present study evaluated the pharmacological effects of the selective cyclooxygenase-2 inhibitor nimesulide on delayed neuronal death of hippocampal CA1 neurons following transient global cerebral ischemia in gerbils. Administration of therapeutically relevant doses of nimesulide (3, 6 and 12 mg/kg; i.p.) 30 min before ischemia and at 6, 12, 24, 48 and 72 h after ischemia significantly (P<0.01) reduced hippocampal neuronal damage. Treatment with a single dose of nimesulide given 30 min before ischemia also resulted in a significant increase in the number of healthy neurons in the hippocampal CA1 sector 7 days after ischemia. Of interest is the finding that nimesulide rescued CA1 pyramidal neurons from ischemic death even when treatment was delayed until 24 h after ischemia (34+/-9% protection). Neuroprotective effect of nimesulide is still evident 30 days after the ischemic episode, providing the first experimental evidence that cyclooxygenase-2 inhibitors confer a long-lasting neuroprotection. Oral administration of nimesulide was also able to significantly reduce brain damage, suggesting that protective effects are independent of the route of administration. The present study confirms the ability of cyclooxygenase-2 inhibitors to reduce brain damage induced by cerebral ischemia and indicates that nimesulide can provide protection when administered for up to 24 h post-ischemia.
Change of Structure of the Cherenkov Emission at Modulated Source in Dispersive Metamaterials
Gennadiy Burlak;Erika Martinez-Sanchez
PIER , 2013,
Abstract: We systematically study the Cherenkov optical emission by a nonrelativistic modulated source crossing 3D dispersive metamaterial. It is found that the interference of the field produced by the modulated source with the periodic plasmonic-polariton excitations in a metamaterial leads to the specific interaction in the frequency range where the dispersive refractive index of a metamaterial is negative and the reversed Cherenkov emission is generated. Such resonance considerably modifies the spatial structure of the Cherenkov field. In our study parameters of a metamaterial and modulated source are fixed while the frequency spectrum of the plasmonic excitations is formed due to the fields interplay in the frequency domain.
MicroRNA Target Identification—Experimental Approaches
Aida Martinez-Sanchez,Chris L. Murphy
Biology , 2013, DOI: 10.3390/biology2010189
Abstract: MicroRNAs (miRNAs) are small non-coding RNA molecules of 21–23 nucleotides that control gene expression at the post-transcriptional level. They have been shown to play a vital role in a wide variety of biological processes and dysregulated expression of miRNAs is observed in many pathologies. Understanding the mechanism of action and identifying functionally important mRNA targets of a specific miRNA are essential to unravelling its biological function and to assist miRNA-based drug development. This review summarizes the current understanding of the mechanistic aspects of miRNA-mediated gene repression and focuses on the different approaches for miRNA target identification that have been proposed in recent years.
The Challenging Road towards a Unified Animal Research Network in Europe
Emma Martinez-Sanchez,Kirk Leech
PLOS Biology , 2015, DOI: 10.1371/journal.pbio.1002157
Abstract: Animal models are key in biomedical research as a proof of concept to study complex processes in a physiological context. Despite the small yet crucial role animals play in fundamental and applied research, the value of animal research is recurrently undermined. Lack of openness and transparency encourages misconceptions, which can have a dramatic negative impact on science and medicine. Research centres should use all available resources to ensure that relevant details about their use of animals in research are readily accessible. More concerted efforts by professional advocacy groups devoted to informing about the benefits of biomedical animal research are also crucial. The European Animal Research Association acts as an umbrella organisation providing support to national advocacy groups and coordinating actions in countries in which no advocacy group exists.
Stem architecture of shade tolerant species in a low-stature tropical rain forest in Mexico
Jose Luis Martinez-Sanchez * , Humberto Hernandez Trejo
International Journal of Biosciences , 2011,
Abstract: The relationship of diameter and height of the stem is an architectural feature that is related to shade tolerance of the trees, as well as mechanical resistance to stem buckling. Theoretically it is postulated a high value of this coefficient for shade-tolerant species. The tropical rain forest of Los Tuxtlas, Mexico is a lowstature forest with higher light levels in the understory, in comparison with other forests in the world. It was estimated the value of the diameter/height coefficient for 275 tree saplings (100-300 cm) of three shadetolerant species and compared with the theoretically proposed values of stem buckling limit in trees. Particularly for this forest and contrary to general assumptions, we expect to find a low coefficient value due to increased height growth in comparison to diameter growth caused by high light levels in the understory. Indeed the three species showed a low coefficient of 0.492 for Guamia sp., 0.745 for Pseudolmedia oxyphyllaira, and 1.15 for Trophis mexicana. This may suggest that the height-diameter coefficient value of the stem for these species is in relation to the high levels of light in this forest in particular.
Medical ozone is now ready for a scientific challenge: current status and future perspectives
Lamberto Re,Giuseppe Malcangi,Gregorio Martinez-Sanchez
Journal of Experimental and Integrative Medicine , 2012, DOI: 10.5455/jeim.070612.ir.012
Abstract: The aim of the present review is to clarify some of the basic mechanisms underlying ozone therapy. Indeed, after its empiric use started at the beginning of the last century, science is now ready to give a chance to the more and more medical doctors working in this field. Unfortunately, the lack of a full recognition by the health authorities and some ostracism against it is, up to date, the major obstacle for its full medical acceptance. Anyway, in the last years and thanks to the contributions of several scientists, most of the mechanisms characterizing the bio-humoral activity of ozone have been scientifically outlined. The built up of randomized clinical studies is going on slowly despite the lack of funds and the difficulties bound mainly to the huge variability of the ozone action. The thousand and thousand medical doctors involved in the use of ozone as emerging therapy, must be fully educated about the properties of this gas in the aim to counteract scientifically the criticisms of colleagues devoted to other field of medicine and not expert of the ozone pharmacological properties. Is for this reason that we encourage all the professionals to deeply increase the knowledge related to the scientific data produced and published on the international literatures in the field of the ozone therapy. For the future we suggest the use of ozone not in alternative but as a complement of the most appropriate pharmacological treatments also in the aim to reduce some side effects derived from a chronic drug use. The lack of a well-defined binding site for the ozone molecule could suggest the introduction of virtual receptors for the supposed biological activity of ozone acting mostly throughout second messengers pathways. [J Exp Integr Med 2012; 2(3.000): 193-196]
A Minimal Regulatory Network of Extrinsic and Intrinsic Factors Recovers Observed Patterns of CD4+ T Cell Differentiation and Plasticity
Mariana Esther Martinez-Sanchez,Luis Mendoza?,Carlos Villarreal?,Elena R. Alvarez-Buylla
PLOS Computational Biology , 2015, DOI: 10.1371/journal.pcbi.1004324
Abstract: CD4+ T cells orchestrate the adaptive immune response in vertebrates. While both experimental and modeling work has been conducted to understand the molecular genetic mechanisms involved in CD4+ T cell responses and fate attainment, the dynamic role of intrinsic (produced by CD4+ T lymphocytes) versus extrinsic (produced by other cells) components remains unclear, and the mechanistic and dynamic understanding of the plastic responses of these cells remains incomplete. In this work, we studied a regulatory network for the core transcription factors involved in CD4+ T cell-fate attainment. We first show that this core is not sufficient to recover common CD4+ T phenotypes. We thus postulate a minimal Boolean regulatory network model derived from a larger and more comprehensive network that is based on experimental data. The minimal network integrates transcriptional regulation, signaling pathways and the micro-environment. This network model recovers reported configurations of most of the characterized cell types (Th0, Th1, Th2, Th17, Tfh, Th9, iTreg, and Foxp3-independent T regulatory cells). This transcriptional-signaling regulatory network is robust and recovers mutant configurations that have been reported experimentally. Additionally, this model recovers many of the plasticity patterns documented for different T CD4+ cell types, as summarized in a cell-fate map. We tested the effects of various micro-environments and transient perturbations on such transitions among CD4+ T cell types. Interestingly, most cell-fate transitions were induced by transient activations, with the opposite behavior associated with transient inhibitions. Finally, we used a novel methodology was used to establish that T-bet, TGF-β and suppressors of cytokine signaling proteins are keys to recovering observed CD4+ T cell plastic responses. In conclusion, the observed CD4+ T cell-types and transition patterns emerge from the feedback between the intrinsic or intracellular regulatory core and the micro-environment. We discuss the broader use of this approach for other plastic systems and possible therapeutic interventions.
AP-3 and Rabip4’ Coordinately Regulate Spatial Distribution of Lysosomes
Viorica Ivan, Emma Martinez-Sanchez, Livia E. Sima, Viola Oorschot, Judith Klumperman, Stefana M. Petrescu, Peter van der Sluijs
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0048142
Abstract: The RUN and FYVE domain proteins rabip4 and rabip4’ are encoded by RUFY1 and differ in a 108 amino acid N-terminal extension in rabip4’. Their identical C terminus binds rab5 and rab4, but the function of rabip4s is incompletely understood. We here found that silencing RUFY1 gene products promoted outgrowth of plasma membrane protrusions, and polarized distribution and clustering of lysosomes at their tips. An interactor screen for proteins that function together with rabip4’ yielded the adaptor protein complex AP-3, of which the hinge region in the β3 subunit bound directly to the FYVE domain of rabip4’. Rabip4’ colocalized with AP-3 on a tubular subdomain of early endosomes and the extent of colocalization was increased by a dominant negative rab4 mutant. Knock-down of AP-3 had an ever more dramatic effect and caused accumulation of lysosomes in protrusions at the plasma membrane. The most peripheral lysosomes were localized beyond microtubules, within the cortical actin network. Our results uncover a novel function for AP-3 and rabip4’ in regulating lysosome positioning through an interorganellar pathway.
Dynamical quark recombination in ultrarelativistic heavy-ion collisions and the proton to pion ratio
Ayala, Alejandro;Martinez, Mauricio;Paic, Guy;Sanchez, G. Toledo
High Energy Physics - Phenomenology , 2007, DOI: 10.1103/PhysRevC.77.044901
Abstract: We study quark thermal recombination as a function of energy density during the evolution of a heavy-ion collision in a numerical model that reproduces aspects of QCD phenomenology. We show that starting with a set of free quarks (or quarks and antiquarks) the probability to form colorless clusters of three quarks differs from that to form colorless clusters of quark-antiquark and that the former has a sharp jump at a critical energy density whereas the latter transits smoothly from the low to the high energy density domains. We interpret this as a quantitative difference in the production of baryons and mesons with energy density. We use this approach to compute the proton and pion spectra in a Bjorken scenario that incorporates the evolution of these probabilities with energy density, and therefore with proper time. From the spectra, we compute the proton to pion ratio and compare to data at the highest RHIC energies. We show that for a standard choice of parameters, this ratio reaches one, though the maximum is very sensitive to the initial evolution proper time.
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