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Search Results: 1 - 10 of 68 matches for " Ailin Lepletier "
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TNF-α Is Involved in the Abnormal Thymocyte Migration during Experimental Trypanosoma cruzi Infection and Favors the Export of Immature Cells
Ana Rosa Pérez, Luiz Ricardo Berbert, Ailin Lepletier, Silvia Revelli, Oscar Bottasso, Suse Dayse Silva-Barbosa, Wilson Savino
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0034360
Abstract: Previous studies revealed a significant production of inflammatory cytokines together with severe thymic atrophy and thymocyte migratory disturbances during experimental Chagas disease. Migratory activity of thymocytes and mature T cells seem to be finely tuned by cytokines, chemokines and extracellular matrix (ECM) components. Systemic TNF-α is enhanced during infection and appears to be crucial in the response against the parasite. However, it also seems to be involved in disease pathology, since it is implicated in the arrival of T cells to effector sites, including the myocardium. Herein, we analyzed the role of TNF-α in the migratory activity of thymocytes in Trypanosoma cruzi (T. cruzi) acutely-infected mice. We found increased expression and deposition of TNF-α in the thymus of infected animals compared to controls, accompanied by increased co-localization of fibronectin, a cell migration-related ECM molecule, whose contents in the thymus of infected mice is also augmented. In-vivo studies showed an enhanced export of thymocytes in T. cruzi-infected mice, as ascertained by intrathymic injection of FITC alone or in combination with TNF-α. The increase of immature CD4+CD8+ T cells in secondary lymphoid organs was even more clear-cut when TNF-α was co-injected with FITC. Ex-vivo transmigration assays also revealed higher number of migrating cells when TNF-α was added onto fibronectin lattices, with higher input of all thymocyte subsets, including immature CD4+CD8+. Infected animals also exhibit enhanced levels of expression of both mRNA TNF-α receptors in the CD4+CD8+ subpopulation. Our findings suggest that in T. cruzi acute infection, when TNF-α is complexed with fibronectin, it favours the altered migration of thymocytes, promoting the release of mature and immature T cells to different compartments of the immune system. Conceptually, this work reinforces the notion that thymocyte migration is a multivectorial biological event in health and disease, and that TNF-α is a further player in the process.
Trypanosoma cruzi Disrupts Thymic Homeostasis by Altering Intrathymic and Systemic Stress-Related Endocrine Circuitries
Ailin Lepletier,Vinicius Frias de Carvalho,Patricia Machado Rodrigues e Silva,Silvina Villar,Ana Rosa Pérez,Wilson Savino ,Alexandre Morrot
PLOS Neglected Tropical Diseases , 2013, DOI: 10.1371/journal.pntd.0002470
Abstract: We have previously shown that experimental infection caused by Trypanosoma cruzi is associated with changes in the hypothalamus-pituitary-adrenal axis. Increased glucocorticoid (GC) levels are believed to be protective against the effects of acute stress during infection but result in depletion of CD4+CD8+ thymocytes by apoptosis, driving to thymic atrophy. However, very few data are available concerning prolactin (PRL), another stress-related hormone, which seems to be decreased during T. cruzi infection. Considering the immunomodulatory role of PRL upon the effects caused by GC, we investigated if intrathymic cross-talk between GC and PRL receptors (GR and PRLR, respectively) might influence T. cruzi-induced thymic atrophy. Using an acute experimental model, we observed changes in GR/PRLR cross-activation related with the survival of CD4+CD8+ thymocytes during infection. These alterations were closely related with systemic changes, characterized by a stress hormone imbalance, with progressive GC augmentation simultaneously to PRL reduction. The intrathymic hormone circuitry exhibited an inverse modulation that seemed to counteract the GC-related systemic deleterious effects. During infection, adrenalectomy protected the thymus from the increase in apoptosis ratio without changing PRL levels, whereas an additional inhibition of circulating PRL accelerated the thymic atrophy and led to an increase in corticosterone systemic levels. These results demonstrate that the PRL impairment during infection is not caused by the increase of corticosterone levels, but the opposite seems to occur. Accordingly, metoclopramide (MET)-induced enhancement of PRL secretion protected thymic atrophy in acutely infected animals as well as the abnormal export of immature and potentially autoreactive CD4+CD8+ thymocytes to the periphery. In conclusion, our findings clearly show that Trypanosoma cruzi subverts mouse thymus homeostasis by altering intrathymic and systemic stress-related endocrine circuitries with major consequences upon the normal process of intrathymic T cell development.
Tumor Necrosis Factor-α Regulates Glucocorticoid Synthesis in the Adrenal Glands of Trypanosoma cruzi Acutely-Infected Mice. The Role of TNF-R1
Silvina R. Villar, M. Teresa Ronco, Rodrigo Fernández Bussy, Eduardo Roggero, Ailin Lepletier, Romina Manarin, Wilson Savino, Ana Rosa Pérez, Oscar Bottasso
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0063814
Abstract: Adrenal steroidogenesis is under a complex regulation involving extrinsic and intrinsic adrenal factors. TNF-α is an inflammatory cytokine produced in response to tissue injury and several other stimuli. We have previously demonstrated that TNF-R1 knockout (TNF-R1?/?) mice have a dysregulated synthesis of glucocorticoids (GCs) during Trypanosoma cruzi acute infection. Since TNF-α may influence GCs production, not only through the hypothalamus-pituitary axis, but also at the adrenal level, we now investigated the role of this cytokine on the adrenal GCs production. Wild type (WT) and TNF-R1?/? mice undergoing acute infection (Tc-WT and Tc-TNF-R1?/? groups), displayed adrenal hyperplasia together with increased GCs levels. Notably, systemic ACTH remained unchanged in Tc-WT and Tc-TNF-R1?/? compared with uninfected mice, suggesting some degree of ACTH-independence of GCs synthesis. TNF-α expression was increased within the adrenal gland from both infected mouse groups, with Tc-WT mice showing an augmented TNF-R1 expression. Tc-WT mice showed increased levels of P-p38 and P-ERK compared to uninfected WT animals, whereas Tc-TNF-R1?/? mice had increased p38 and JNK phosphorylation respect to Tc-WT mice. Strikingly, adrenal NF-κB and AP-1 activation during infection was blunted in Tc-TNF-R1?/? mice. The accumulation of mRNAs for steroidogenic acute regulatory protein and cytochrome P450 were significantly increased in both Tc-WT and Tc-TNF-R1?/? mice; being much more augmented in the latter group, which also had remarkably increased GCs levels. TNF-α emerges as a potent modulator of steroidogenesis in adrenocortical cells during T. cruzi infection in which MAPK pathways, NF-κB and AP-1 seem to play a role in the adrenal synthesis of pro-inflammatory cytokines and enzymes regulating GCs synthesis. These results suggest the existence of an intrinsic immune-adrenal interaction involved in the dysregulated synthesis of GCs during murine Chagas disease.
Fourier Truncation Method for Fractional Numerical Differentiation  [PDF]
Ailin Qian, Jianfeng Mao
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.27124
Abstract: We consider a ill-posed problem-fractional numerical differentiation with a new method. We propose Fourier truncation method to compute fractional numerical derivatives. A Holder-type stability estimate is obtained. A numerical implementation is described. Numerical examples show that the proposed method is effective and stable.
Quasi-Reversibility Regularization Method for Solving a Backward Heat Conduction Problem  [PDF]
Ailin Qian, Jianfeng Mao
American Journal of Computational Mathematics (AJCM) , 2011, DOI: 10.4236/ajcm.2011.13018
Abstract: Non-standard backward heat conduction problem is ill-posed in the sense that the solution(if it exists) does not depend continuously on the data. In this paper, we propose a regularization strategy-quasi-reversibility method to analysis the stability of the problem. Meanwhile, we investigate the roles of regularization parameter in this method. Numerical result show that our algorithm is effective and stable.
Four-quark state in QCD
Ailin Zhang
Physics , 2000, DOI: 10.1103/PhysRevD.61.114021
Abstract: The spectra of some 0++ four-quark states, which are composed of \bar qq pairs, are calculated in QCD. The light four-quark states are calculated using the traditional sum rules while four-quark states containing one heavy quark are computed in HQET. For constructing the interpolating currents, different couplings of the color and spin inside the \bar qq pair are taken into account. It is found that the spin and color combination has little effect on the mass of the four-quark states.
Regge Trajectories Analysis to DsJ(2317), DsJ(2460) and DsJ(2632) Mesons
Ailin Zhang
Physics , 2004, DOI: 10.1103/PhysRevD.72.017902
Abstract: Status of investigations of the new observed charmed strange mesons DsJ(2317), DsJ(2460) and DsJ(2632) is simply listed. A systemic classification to these states with Regge trajectories was made. We found that DsJ(2317) and DsJ(2460) are reasonable to be arranged as (0^+,1^+), but DsJ(2632) seems not possible to be an orbital excited tensor particle. As a byproduct, the non-strange charmed mesons including D'1(2427) and D*(2637) were analyzed also.
Charmonium spectrum and new observed states
Ailin Zhang
Physics , 2006, DOI: 10.1016/j.physletb.2007.01.062
Abstract: The linearity and parallelism of Regge trajectories is combined with a hyperfine splitting relation in multiplet to study charmonium spectrum. It is found that predictions to the spectrum of 1D multiplet could be made once another 1D state is confirmed. The newly observed X(3872), Y(3940), X(3940), Y(4260) and Z(3930) are studied within the charmonium framework.
Early Double-Negative Thymocyte Export in Trypanosoma cruzi Infection Is Restricted by Sphingosine Receptors and Associated with Human Chagas Disease
Ailin Lepletier,Liliane de Almeida,Leonardo Santos,Luzia da Silva Sampaio,Bruno Paredes,Florencia Belén González,Célio Geraldo Freire-de-Lima,Juan Beloscar,Oscar Bottasso,Marcelo Einicker-Lamas,Ana Rosa Pérez,Wilson Savino,Alexandre Morrot
PLOS Neglected Tropical Diseases , 2014, DOI: 10.1371/journal.pntd.0003203
Abstract: The protozoan parasite Trypanosoma cruzi is able to target the thymus and induce alterations of the thymic microenvironmental and lymphoid compartments. Acute infection results in severe atrophy of the organ and early release of immature thymocytes into the periphery. To date, the pathophysiological effects of thymic changes promoted by parasite-inducing premature release of thymocytes to the periphery has remained elusive. Herein, we show that sphingosine-1-phosphate (S1P), a potent mediator of T cell chemotaxis, plays a role in the exit of immature double-negative thymocytes in experimental Chagas disease. In thymuses from T. cruzi-infected mice we detected reduced transcription of the S1P kinase 1 and 2 genes related to S1P biosynthesis, together with increased transcription of the SGPL1 sphingosine-1-lyase gene, whose product inactivates S1P. These changes were associated with reduced intrathymic levels of S1P kinase activity. Interestingly, double-negative thymocytes from infected animals expressed high levels of the S1P receptor during infection, and migrated to lower levels of S1P. Moreover, during T. cruzi infection, this thymocyte subset expresses high levels of IL-17 and TNF-α cytokines upon polyclonal stimulation. In vivo treatment with the S1P receptor antagonist FTY720 resulted in recovery the numbers of double-negative thymocytes in infected thymuses to physiological levels. Finally, we showed increased numbers of double-negative T cells in the peripheral blood in severe cardiac forms of human Chagas disease.
Based on the Efficiency Coefficient-BP Neural Network Study of the Risk of Early Warning
Yonghong TAO,Ailin QI
Management Science and Engineering , 2009,
Abstract: We all expect that we can predict the risk before it appears, the risk of early-warning has become a research hotspot in many fields, so does the economy of risk early-warning. In recent years, using Artificial Neural Network to solve the risk of early warning problem has been developed, but the risk of early warning process often encounters such a problem: The risk assessment has no standard, meanwhile BP Neural Network is a kind of instructors train, and instructors come from the standard. This paper combines Efficacy Coefficient Method and BP Neural Network to achieve the purpose of early warning on the economy problem, it has remedies the limitation of risk of early warning by simply using BP neural network. Key words: Risk Early Warning, Efficiency Coefficient Method, BP Neural Network
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