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Finite Element Analysis of the Seismic Behavior of Guyed MastsHensley, Gregory Martin 14 July 2005 (has links)
Seismic design of guyed masts, commonly used in the broadcasting and telecommunications industries, has not been fully addressed in the United States. There is no specific design code, and only a limited amount of research has been reported on the subject. This research investigates the behavior of guyed masts incorporating synthetic ropes as guys, with a particular focus on the effect of snap loads on the mast behavior. This is the third phase of a multi-stage project aimed at analyzing the potential for Snapping-Cable Energy Dissipators (SCEDs) to minimize lateral response in structures.
A finite element model of a 120-m-tall guyed mast was developed with the commercial program ABAQUS. The three-dimensional behavior of the mast was observed when subjected to two ground motion records: Northridge and El Centro. Three orthogonal earthquake components were input, two horizontal and one vertical. A series of parametric studies was conducted to determine the sensitivity of the response to guy pretension, which is a measure of the potential slackness in the guys during response. Additionally, the studies examined the effects of guy stiffness, mast properties, and directionality of input motion.
Deflections, bending moments, guy tensions, and base shears were examined. The results were used to characterize the trends in the structural response of guyed masts. The level of slackness in the guys changed the behavior, and the lessons learned will be used to continue research on the application of SCEDs in structures. / Master of Science
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\"O museu vai à praia\": análise de uma ação educativa à luz da alfabetização científica / The museum goes to the beach\": analysis of an educational action under the perspective of a scientific literacyMingues, Eliane 18 September 2014 (has links)
Esta investigação caracteriza-se por ser estudo qualitativo que buscou compreender quais as características e as evidências da alfabetização científica presentes na ação educativa O Museu Vai à Praia, iniciativa desenvolvida pelo Museu de Astronomia e Ciências Afins (MAST) que leva atividades do museu para a praia durante o verão. Os dados deste estudo foram coletados durante o mês de março de 2013, no Rio de Janeiro e em três praias diferentes da cidade de Niterói, contemplando, além de entrevistas com os conceptores da ação educativa e com o público espontâneo, a observação da ação e a análise documental do projeto. A revisão da literatura referente à alfabetização científica e à educação em museus possibilitou o desenvolvimento de uma ferramenta de análise composta de dimensões e seus respectivos indicadores, usados para análise de dois importantes aspectos do O Museu Vai à Praia: as intenções do programa nos anos 1980 e em 2013 e a experiência do púbico na sua quinta edição. Os resultados revelam que, apesar de o projeto não ter sido elaborado na perspectiva da Alfabetização Científica (AC), ela contempla todas as dimensões propostas: Científica, Interface Ciência e Sociedade, Institucional e Afetiva, além da maioria dos indicadores de cada uma das dimensões. Mesmo nem todos os indicadores estando explicitados, consideramos que a presença reiterada de todas as dimensões denota que, desde sua origem, os objetivos da ação O Museu Vai à Praia dialogam com as finalidades da alfabetização científica. A ausência de alguns dos indicadores foi problematizada, assim como foram discutidas as mudanças nas ênfases de algumas dimensões ocorridas entre os anos 1980 e 2013, com a finalidade de promover uma análise crítica e uma reflexão sobre o papel da ação O Museu Vai à Praia na perspectiva da AC. Ao se defender que a AC é um processo que ocorre ao longo da vida, avaliamos que as ações educativas desenvolvidas pelos museus de ciências possuem grande potencial para sua promoção e que tais ações, se planejadas com base nas dimensões e nos indicadores propostos, podem se mostrar como um recurso fundamental para a maior compreensão da ciência e de sua relação com a sociedade. / This investigation is a qualitative study that aims to understand the evidences and characteristics of scientific literacy present in the project \"The Museum goes to the Beach\", an initiative developed by MAST (Museum of Astronomy and Science), which takes museum activities to the beach during summer.Data was collected in March 2013 in Rio de Janeiro and in three different beaches of Niteroi. Besides interviews with the creators of the project and the spontaneous public, we conducted a documental analysis and an observation of activities. The literature review on scientific literacy and education in museums allowed the development of an analytical tool regarding dimensions and indicators of \"the musem goes to the beach\" that focus on two specific aspects: the intention of the project in the 1980s and in 2013 and the experience with the participants in its fifth edition.Results indicate that even though the project was not built under the perspective of scientific literacy, it involves all the proposed dimensions: scientific, science and society interface, institutional and affective, besides the majority of indicators in each of the dimensions.Even though not all indicators are explicit, we believe that the consistent presence of all the dimensions reinforce that, since its origin, the objectives of \"the museum goes to the beach\" dialogue with the goals of scientific literacy.The absence of some indicators was analyzed, such as the change in emphasis in some dimensions between the 1980s and 2013 was discussed, in the attempt to foster a critical analysis and reflection over the role of the activity \"the museum goes to the beach\", under the perspective of scientific literacy.Stating that scientific education is a process ongoing throughout life, it is evaluated that educational activities developed by science museums have great potential to its promotion. This kind of activities, if based on the proposed dimensions and indicators, can be a fundamental resource to a deeper understanding of science and its relation with society.
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Bystander Cells and Prognosis in Hodgkin LymphomaMolin, Daniel January 2002 (has links)
<p>Hodgkin lymphoma (HL) is characterised histologically by a minority of malignant Hodgkin and Reed-Sternberg (HRS) cells surrounded by benign cells, and clinically by a relatively good prognosis. The treatment, however, leads to a risk of serious side effects. Knowledge about the biology of the disease, particularly the interaction between the HRS cells and the surrounding cells, is essential in order to improve diagnosis and treatment. </p><p>HL patients with abundant eosinophils in the tumours have a poor prognosis, therefore the eosinophil derived protein eosinophil cationic protein (ECP) was studied. Serum-ECP (S-ECP) was elevated in most HL patients. It correlated to number of tumour eosinophils, nodular sclerosis (NS) histology, and the negative prognostic factors high erythrocyte sedimentation rate (ESR) and blood leukocyte count (WBC). A polymorphism in the ECP gene (434(G>C)) was identified and the 434GG genotype correlated to NS histology and high ESR.</p><p>The poor prognosis in patients with abundant eosinophils in the tumours has been proposed to depend on HRS cell stimulation by the eosinophils via a CD30 ligand (CD30L)-CD30 interaction. However, CD30L mRNA and protein were detected in mast cells and the predominant CD30L expressing cell in HL is the mast cell. Mast cells were shown to stimulate HRS cell lines via CD30L-CD30 interaction. The number of mast cells in HL tumours correlated to worse relapse-free survival, NS histology, high WBC, and low blood haemoglobin. </p><p>Survival in patients with early and intermediate stage HL, diagnosed between 1985 and 1992, was generally favourable and comparatively limited treatment was sufficient to produce acceptable results for most stages. The majority of relapses could be salvaged. Patients treated with a short course of chemotherapy and radiotherapy had an excellent outcome.</p><p>In conclusion prognosis is favourable in early and intermediate stages and there are possibilities for further improvements based on the fact that mast cells and eosinophils affect the biology and prognosis of HL.</p>
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Bystander Cells and Prognosis in Hodgkin LymphomaMolin, Daniel January 2002 (has links)
Hodgkin lymphoma (HL) is characterised histologically by a minority of malignant Hodgkin and Reed-Sternberg (HRS) cells surrounded by benign cells, and clinically by a relatively good prognosis. The treatment, however, leads to a risk of serious side effects. Knowledge about the biology of the disease, particularly the interaction between the HRS cells and the surrounding cells, is essential in order to improve diagnosis and treatment. HL patients with abundant eosinophils in the tumours have a poor prognosis, therefore the eosinophil derived protein eosinophil cationic protein (ECP) was studied. Serum-ECP (S-ECP) was elevated in most HL patients. It correlated to number of tumour eosinophils, nodular sclerosis (NS) histology, and the negative prognostic factors high erythrocyte sedimentation rate (ESR) and blood leukocyte count (WBC). A polymorphism in the ECP gene (434(G>C)) was identified and the 434GG genotype correlated to NS histology and high ESR. The poor prognosis in patients with abundant eosinophils in the tumours has been proposed to depend on HRS cell stimulation by the eosinophils via a CD30 ligand (CD30L)-CD30 interaction. However, CD30L mRNA and protein were detected in mast cells and the predominant CD30L expressing cell in HL is the mast cell. Mast cells were shown to stimulate HRS cell lines via CD30L-CD30 interaction. The number of mast cells in HL tumours correlated to worse relapse-free survival, NS histology, high WBC, and low blood haemoglobin. Survival in patients with early and intermediate stage HL, diagnosed between 1985 and 1992, was generally favourable and comparatively limited treatment was sufficient to produce acceptable results for most stages. The majority of relapses could be salvaged. Patients treated with a short course of chemotherapy and radiotherapy had an excellent outcome. In conclusion prognosis is favourable in early and intermediate stages and there are possibilities for further improvements based on the fact that mast cells and eosinophils affect the biology and prognosis of HL.
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\"O museu vai à praia\": análise de uma ação educativa à luz da alfabetização científica / The museum goes to the beach\": analysis of an educational action under the perspective of a scientific literacyEliane Mingues 18 September 2014 (has links)
Esta investigação caracteriza-se por ser estudo qualitativo que buscou compreender quais as características e as evidências da alfabetização científica presentes na ação educativa O Museu Vai à Praia, iniciativa desenvolvida pelo Museu de Astronomia e Ciências Afins (MAST) que leva atividades do museu para a praia durante o verão. Os dados deste estudo foram coletados durante o mês de março de 2013, no Rio de Janeiro e em três praias diferentes da cidade de Niterói, contemplando, além de entrevistas com os conceptores da ação educativa e com o público espontâneo, a observação da ação e a análise documental do projeto. A revisão da literatura referente à alfabetização científica e à educação em museus possibilitou o desenvolvimento de uma ferramenta de análise composta de dimensões e seus respectivos indicadores, usados para análise de dois importantes aspectos do O Museu Vai à Praia: as intenções do programa nos anos 1980 e em 2013 e a experiência do púbico na sua quinta edição. Os resultados revelam que, apesar de o projeto não ter sido elaborado na perspectiva da Alfabetização Científica (AC), ela contempla todas as dimensões propostas: Científica, Interface Ciência e Sociedade, Institucional e Afetiva, além da maioria dos indicadores de cada uma das dimensões. Mesmo nem todos os indicadores estando explicitados, consideramos que a presença reiterada de todas as dimensões denota que, desde sua origem, os objetivos da ação O Museu Vai à Praia dialogam com as finalidades da alfabetização científica. A ausência de alguns dos indicadores foi problematizada, assim como foram discutidas as mudanças nas ênfases de algumas dimensões ocorridas entre os anos 1980 e 2013, com a finalidade de promover uma análise crítica e uma reflexão sobre o papel da ação O Museu Vai à Praia na perspectiva da AC. Ao se defender que a AC é um processo que ocorre ao longo da vida, avaliamos que as ações educativas desenvolvidas pelos museus de ciências possuem grande potencial para sua promoção e que tais ações, se planejadas com base nas dimensões e nos indicadores propostos, podem se mostrar como um recurso fundamental para a maior compreensão da ciência e de sua relação com a sociedade. / This investigation is a qualitative study that aims to understand the evidences and characteristics of scientific literacy present in the project \"The Museum goes to the Beach\", an initiative developed by MAST (Museum of Astronomy and Science), which takes museum activities to the beach during summer.Data was collected in March 2013 in Rio de Janeiro and in three different beaches of Niteroi. Besides interviews with the creators of the project and the spontaneous public, we conducted a documental analysis and an observation of activities. The literature review on scientific literacy and education in museums allowed the development of an analytical tool regarding dimensions and indicators of \"the musem goes to the beach\" that focus on two specific aspects: the intention of the project in the 1980s and in 2013 and the experience with the participants in its fifth edition.Results indicate that even though the project was not built under the perspective of scientific literacy, it involves all the proposed dimensions: scientific, science and society interface, institutional and affective, besides the majority of indicators in each of the dimensions.Even though not all indicators are explicit, we believe that the consistent presence of all the dimensions reinforce that, since its origin, the objectives of \"the museum goes to the beach\" dialogue with the goals of scientific literacy.The absence of some indicators was analyzed, such as the change in emphasis in some dimensions between the 1980s and 2013 was discussed, in the attempt to foster a critical analysis and reflection over the role of the activity \"the museum goes to the beach\", under the perspective of scientific literacy.Stating that scientific education is a process ongoing throughout life, it is evaluated that educational activities developed by science museums have great potential to its promotion. This kind of activities, if based on the proposed dimensions and indicators, can be a fundamental resource to a deeper understanding of science and its relation with society.
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Masting and insect pollination in the dioecious alpine herb aciphyllaYoung, Laura May January 2006 (has links)
Aciphylla species (wild spaniard/speargrass) are an iconic component of the Australasian high country flora, but their reproductive system is enigmatic. They are insect-pollinated dioecious mast seeders (synchronous highly variable seed production), which seems maladaptive. The resource supply to pollinators is highly variable, yet dioecious plants are dependent on pollinators, and dioecious masting requires male and female plants to flower synchronously. Floral display in Aciphylla is relatively large, with tall inflorescences bearing thousands of flowers, suggesting that plants would not have the resources to produce such large stalks every year. But why do they have such huge inflorescences in the first place? I tested whether pollinator attraction is providing an economy of scale which favours intermittent production of very large inflorescences, by manipulating floral display size during a high-flowering year and measuring insect visitation rates and seed set (female reproductive success). Using space-for-time substitution and selective removal of male inflorescences, I also tested whether female seed set was affected by distance to flowering male plants (i.e. changes in local pollen availability) to see if flowering asynchrony would reduce pollination success. Bags were used to exclude pollination by insects and test for wind pollination, and hand pollination was done to test for pollen limitation. Insect surveys suggest that Aciphylla has a generalist pollination system (to avoid satiating a specialist pollinator during 'mast' years'). Male inflorescences received significantly more visits than females, and some seeds were set inside bags (although only 20-30%), suggesting wind pollination may occur at low levels. Seed set rate was higher for taller inflorescences with greater flowering length in A. aurea but tall inflorescences with excess flowers led to a decrease in seed set rates in A. scott-thomsonii. Hand pollination significantly increased seed set rates although these effects were not as large as expected (e.g. 10% increases from natural to hand-pollinated inflorescences were typical). There was no evidence for resource limitation in any species. Female plants in dense flowering populations had higher seed set rates, and individual floral display size in females was particularly important when females were 'isolated' from males. Insect visitation rates were generally higher on inflorescences with a larger floral display, suggesting that display size is important for pollinator attraction. Overall, these results suggest that the pollinator-attraction benefits of such a large floral display (at both the plant and population level) are possibly providing an economy of scale, although the relative effects are small.
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Incremento de Linfocitos Intraepiteliales en pacientes con Síndrome de Intestino IrritableArévalo, F., Aragon, V., Montes, P., Guzmán, E., Monge, E. 11 August 2014 (has links)
Diversos trabajos reportan aumento en el número de linfocitos intraepiteliales (LIE), mastocitos y células enterocromafines en pacientes con Sindrome de Intestino Irritable (SII). Muchos de estos hallazgos se basan en el uso de inmunohistoquímica que son de poca disponibilidad en hospitales generales. El objetivo del presente trabajo es estudiar los hallazgos histológicos en la biopsia de colon sólo con histoquimica en pacientes con SII comparándolos con un grupo sin SII. Fueron incluidos 25 pacientes: 16 (64%), con criterios diagnósticos de SII y 9 (36%), sin SII. Se encontró un mayor número de LIE en el grupo de SII (p=0,002). Un grupo de pacientes con criterios Roma III (41,9%) presentó LIE en el rango de Colitis Linfocitica por lo que fueron excluidos de este estudio. No se encontró diferencia estadísticamente significativa en el número de mastocitos, células enterocromafines y eosinofilos. / Several studies have shown increased numbers of intraepithelial lymphocytes (IEL), mast cells, enterochromaffin cells in colonic mucosa of patients with Irritable Bowel Syndrome (IBS). Many of these findings are based is based on immunohistochemistry results, which is not available in general hospitals. Our objective is to study the histological findings observed in colon biopsies from patients with IBS compared with a group without IBS, using only histochemistry. Twenty five (25) patients were included: 16 with IBS and 9 without IBS. We found increased numbers of IEL in patients with IBS (p=0,002). A group of patients with IBS (41.9%) who fulfilled histological criteria for lymphocytic colitis were excluded. There was no significant difference in mast cells, enterochromaffin cells or eosinophils.
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ADAM10 overexpression dysregulates Notch signaling in favor of myeloid derived suppressor cell (MDSC) accumulation that deferentially modulates the host response depending on immune stimuli and interaction with mast cells.Saleem, Sheinei 08 July 2013 (has links)
Although the physiological consequences of Notch signaling in hematopoiesis have been extensively studied, the differential effects of individual notch cleavage products remain to be elucidated. Given that a disintegrin and metalloproteinase 10 (ADAM10) is a critical regulator of Notch and that its deletion is embryonically lethal, we generated transgenic mice that overexpress ADAM10 at early stages of lymphoid and myeloid development (A10Tg). ADAM10 transgene expression alters hematopoiesis post-hematopoietic Lineage-Sca-1+c-kit+ (LSK) subset differentiation but prior to lineage commitment of progenitor populations. This results in delayed T cell development, abrogated B2 cell development, and dramatic expansion of functionally active myeloid derived suppressor cells (MDSCs) in A10Tg mice. Given ADAM10’s role in Notch signaling, we hypothesized that the observed hematopoietic alterations may be a consequence of perturbed Notch signaling. In fact, blockade of ADAM10 (S2) rescues B cell development and reduces myeloid cells in A10Tg LSKs. Inhibition of γ-secretase (S3) in wild type (WT) LSKs results in enhanced myelopoiesis, mimicking the phenotype of A10Tg mice. Collectively, these findings indicate that the differential cleavage of Notch into S2 and S3 products regulated by ADAM10 is critical for hematopoietic cell-fate determination. Albeit arising in a tumor-free host, A10Tg MDSCs are functionally and phenotypically analogous to tumor-derived MDSCs. A10Tg MDSCs inhibit T cell activation in vitro, and inhibit adoptive immunotherapy (AIT) of metastatic melanoma in vivo, which can be reversed with MDSC depletion. Intriguingly, A10Tg mice are resistant to parasitic infection upon inoculation of Nippostrongylus brasiliensis. However, depletion of MDSCs abrogates this response, while adoptive transfer (AT) of MDSCs into WT mice increases their resistance. This polarized activity of MDSCs is heavily dependent upon interaction with mast cells (MCs). In fact, B16 melanoma cells metastasize more rapidly in WT mice infused with MDSCs when compared to MC-deficient mice (Kit Wsh/Wsh), with or without MDSC AT. Parallel to B16 progression, the ability of MDSCs to promote anti-Nb immunity is significantly diminished in MC-deficient (Kit Wsh/Wsh) mice even with MDSC AT. This augmentation of MDSC activity in the presence of MCs is further corroborated by in vitro co-culture assays that demonstrate a synergistic increase in cytokine production. Furthermore, MDSCs preferentially migrate to the liver in a MC-dependent manner. This interaction is mediated by MC-released histamine. In fact, MDSCs express histamine receptors (HR) and histamine induces MDSC survival, proliferation, and activation. We demonstrate that MDSC activity is abrogated with histamine blockade. Moreover, in humans, allergic patients present with an increase in MDSC population, and MDSCs purified from a stage I breast cancer patient exhibit increased survival in the presence of histamine. Taken together, our studies indicate that MCs and MC-released histamine are critical for the observed functional duality of MDSCs, ranging from immunosuppressive to immunosupportive, depending on the disease state.
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Sphingosine-1-phosphate in mast cell-mediated allergic responsesPrice, Megan 27 July 2011 (has links)
Mast cells play a critical role in both acute and chronic inflammation and mature in peripheral tissues from bone marrow-derived progenitors that circulate in the blood as immature precursors. Mast cell progenitors are likely to encounter the serum-borne bioactive sphingolipid metabolite, sphingosine-1-phosphate (S1P), during migration to target tissues. Mast cells developed from human cord blood-derived progenitors cultured with stem cell factor (SCF) alone express intragranular tryptase (MCT), the phenotype predominant in the lung. S1P accelerated the development of cord blood-derived mast cells (CB-MCs) and strikingly increased the numbers of mast cells expressing chymase. These mast cells have functional FcepsilonRI, and similar to skin mast cells that express both tryptase and chymase (MCTC), also express CD88, the receptor for C5a, and are activated by anaphylatoxin C5a and the secretagogue compound 48/80. S1P induced release of IL-6, a cytokine known to promote development of functionally mature MCTC, from cord blood cultures containing adherent macrophages, and from highly purified macrophages, but not from macrophage-depleted CB-MCs. In contrast, S1P stimulated secretion of the chemokine, monocyte chemoattractant protein 1 (MCP-1/CCL2), from these macrophage-depleted and purified CB-MCs.
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Control of type I allergy by regulatory T cells / Contrôle de l'allergie de type I par les lymphocytes T régulateursKanjarawi, Reem 03 December 2010 (has links)
L’allergie de type I, une réaction de type hypersensibilité immédiate (HIS), a considérablement augmenté au cours des dernières décades dans les pays industrialisés. Le rôle des lymphocytes T régulateurs (Treg) dans le contrôle des maladies allergiques a été récemment apprécié. Cependant, il n’existe actuellement aucune connaissance précise si et comment les CD4+ Treg peuvent réguler l’allergie de type I. Le but du projet était d’étudier la contribution de cellules Treg dans le contrôle de l’allergie de type I chez la souris et chez l’homme. En utilisant un modèle murin d’HSI aux protéines de lait de vache, ß-lactoglobuline(BLG), nous avons montré que l’absence de Treg augmentait les réponses des cytokines Th1et Th2 et des anticorps IgE, IgG1 et IgG2a spécifique de la BLG. De plus, l’absence de Treg a augmenté la sévérité de l’anaphylaxie chez les souris sensibilisées lors de l’épreuve orale avec la BLG, avec une augmentation concomitante de la protéase des mastocytes muqueux 1(mMCP-1) dans le sérum. La contribution des cellules Treg dans un modèle murin d’anaphylaxie systémique passive (PSA) a été également étudiée. Une anaphylaxie plus sévère a été observée chez les souris déficientes en CHM de classe II ainsi que chez des souris B6 traitées avec un anti-CD4. En revanche, la déplétion sélective des Foxp3+ Treg chez des souris Tg DEREG n’a pas d’effet sur l’anaphylaxie.La capacité des Treg à contrôler la dégranulation des basophiles a été étudiée chez l’homme. Les données préliminaires ont montré que les Treg ont été incapables de contrôler la dégranulation des basophiles chez les donneurs sains. En revanche, une légère mais reproductible down-regulation de la dégranulation/activation des basophiles a été observée dans l’allergie induite par les médicaments chez l’homme. Dans l’ensemble, notre travail met en évidence un nouveau rôle encore non identifié des Treg dans le contrôle de l’HSI et souligne que chez la souris et l’homme, les Treg peuvent dans certaines conditions, limiter la sévérité de l’HSI en agissant sur les mastocytes et/ou basophiles effecteurs / Type I allergy, an immediate type hypersensitivity reaction (ITH), has dramatically increased during the past decades affecting up to 30% of the population in industrialized countries. The role of regulatory T cells (Treg) in the control of allergic diseases has been recently appreciated. However, there is currently no precise knowledge of whether and howCD4+ Treg can regulate type I allergy. The aim of this project was to investigate the contribution of Treg in the control of type I allergy. Using a murine model of ITH to cow’s milk protein the ß-lactoglobulin (BLG), we showed that lack of Treg increased BLG-specific Th2 and Th1 cytokine response and BLG-specific IgE, IgG1 and IgG2a antibodies.Furthermore, absence of Treg enhanced the severity of the anaphylaxis with concomitant increase in serum mucosal mast cell protease 1 (mMCP-1) in sensitized mice upon oral challenge with BLG. Furthermore, we investigated the contribution of Treg in a murine model of passive systemic anaphylaxis (PSA). More sever anaphylaxis was observed in both MHCclass II KO mice and after anti-CD4 mAb treatment. Alternatively, selective depletion of Foxp3+ Treg in DEREG Tg mice did not show changes in anaphylaxis.The capacity of Treg to control basophils degranulation was investigated in humans. Preliminary data showed that Treg were unable to control basophils degranulation in healthy donors. In contrast, a slight butreproducible downregulation of basophils activation/ degranulation was observed in allergic individuals. Taken together, our work points out to a novel as yet unidentified role of Treg in the control of ITH and emphasizes that both mouse and human Treg can, in certain conditions, limit the severity of ITH by acting on mast cells and/or basophils effectors of ITH
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