215 research outputs found

    Three little pieces for computer and relativity

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    Numerical relativity has made big strides over the last decade. A number of problems that have plagued the field for years have now been mostly solved. This progress has transformed numerical relativity into a powerful tool to explore fundamental problems in physics and astrophysics, and I present here three representative examples. These "three little pieces" reflect a personal choice and describe work that I am particularly familiar with. However, many more examples could be made.Comment: 42 pages, 11 figures. Plenary talk at "Relativity and Gravitation: 100 Years after Einstein in Prague", June 25 - 29, 2012, Prague, Czech Republic. To appear in the Proceedings (Edition Open Access). Collects results appeared in journal articles [72,73, 122-124

    Modulation of the Effects of Lung Immune Response on Bone Marrow by Oral Antigen Exposure

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    Allergic airway inflammation is attenuated by oral tolerization (oral exposure to allergen, followed by conventional sensitization and challenge with homologous antigen), which decreases airway allergen challenge-induced eosinophilic infiltration of the lungs and bone marrow eosinophilia. We examined its effects on bone marrow eosinophil and neutrophil production. Mice of wild type (BP-2, BALB/c, and C57BL/6) and mutant strains (lacking iNOS or CD95L) were given ovalbumin (OVA) or water (vehicle) orally and subsequently sensitized and challenged with OVA (OVA/OVA/OVA and H(2)O/OVA/OVA groups, resp.). Anti-OVA IgG and IgE, bone marrow eosinophil and neutrophil numbers, and eosinophil and neutrophil production ex vivo were evaluated. T lymphocytes from OVA/OVA/OVA or control H(2)O/OVA/OVA donors were transferred into naïve syngeneic recipients, which were subsequently sensitized/challenged with OVA. Alternatively, T lymphocytes were cocultured with bone marrow eosinophil precursors from histocompatible sensitized/challenged mice. OVA/OVA/OVA mice of the BP-2 and BALB/c strains showed, relative to H(2)O/OVA/OVA controls, significantly decreased bone marrow eosinophil counts and ex vivo eosinopoiesis/neutropoiesis. Full effectiveness in vivo required sequential oral/subcutaneous/intranasal exposures to the same allergen. Transfer of splenic T lymphocytes from OVA/OVA/OVA donors to naive recipients prevented bone marrow eosinophilia and eosinopoiesis in response to recipient sensitization/challenge and supressed eosinopoiesis upon coculture with syngeneic bone marrow precursors from sensitized/challenged donors

    Modulation of the Effects of Lung Immune Response on Bone Marrow by Oral Antigen Exposure

    Get PDF
    Allergic airway inflammation is attenuated by oral tolerization (oral exposure to allergen, followed by conventional sensitization and challenge with homologous antigen), which decreases airway allergen challenge-induced eosinophilic infiltration of the lungs and bone marrow eosinophilia. We examined its effects on bone marrow eosinophil and neutrophil production. Mice of wild type (BP-2, BALB/c, and C57BL/6) and mutant strains (lacking iNOS or CD95L) were given ovalbumin (OVA) or water (vehicle) orally and subsequently sensitized and challenged with OVA (OVA/OVA/OVA and H 2 O/OVA/OVA groups, resp.). Anti-OVA IgG and IgE, bone marrow eosinophil and neutrophil numbers, and eosinophil and neutrophil production ex vivo were evaluated. T lymphocytes from OVA/OVA/OVA or control H 2 O/OVA/OVA donors were transferred into naïve syngeneic recipients, which were subsequently sensitized/challenged with OVA. Alternatively, T lymphocytes were cocultured with bone marrow eosinophil precursors from histocompatible sensitized/challenged mice. OVA/OVA/OVA mice of the BP-2 and BALB/c strains showed, relative to H 2 O/OVA/OVA controls, significantly decreased bone marrow eosinophil counts and ex vivo eosinopoiesis/neutropoiesis. Full effectiveness in vivo required sequential oral/subcutaneous/intranasal exposures to the same allergen. Transfer of splenic T lymphocytes from OVA/OVA/OVA donors to naive recipients prevented bone marrow eosinophilia and eosinopoiesis in response to recipient sensitization/challenge and supressed eosinopoiesis upon coculture with syngeneic bone marrow precursors from sensitized/challenged donors

    p53 Interaction with JMJD3 Results in Its Nuclear Distribution during Mouse Neural Stem Cell Differentiation

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    Conserved elements of apoptosis are also integral components of cellular differentiation. In this regard, p53 is involved in neurogenesis, being required for neurite outgrowth in primary neurons and for axonal regeneration in mice. Interestingly, demethylases regulate p53 activity and its interaction with co-activators by acting on non-histone proteins. In addition, the histone H3 lysine 27-specific demethylase JMJD3 induces ARF expression, thereby stabilizing p53 in mouse embryonic fibroblasts. We hypothesized that p53 interacts with key regulators of neurogenesis to redirect stem cells to differentiation, as an alternative to cell death. Specifically, we investigated the potential cross-talk between p53 and JMJD3 during mouse neural stem cell (NSC) differentiation. Our results demonstrated that JMJD3 mRNA and protein levels were increased early in mouse NSC differentiation, when JMJD3 activity was readily detected. Importantly, modulation of JMJD3 in NSCs resulted in changes of total p53 protein, coincident with increased ARF mRNA and protein expression. ChIP analysis revealed that JMJD3 was present at the promoter and exon 1 regions of ARF during neural differentiation, although without changes in H3K27me3. Immunoprecipitation assays demonstrated a direct interaction between p53 and JMJD3, independent of the C-terminal region of JMJD3, and modulation of p53 methylation by JMJD3-demethylase activity. Finally, transfection of mutant JMJD3 showed that the demethylase activity of JMJD3 was crucial in regulating p53 cellular distribution and function. In conclusion, JMJD3 induces p53 stabilization in mouse NSCs through ARF-dependent mechanisms, directly interacts with p53 and, importantly, causes nuclear accumulation of p53. This suggests that JMJD3 and p53 act in a common pathway during neurogenesis

    Distinct Regulatory Functions of Calpain 1 and 2 during Neural Stem Cell Self-Renewal and Differentiation

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    Calpains are calcium regulated cysteine proteases that have been described in a wide range of cellular processes, including apoptosis, migration and cell cycle regulation. In addition, calpains have been implicated in differentiation, but their impact on neural differentiation requires further investigation. Here, we addressed the role of calpain 1 and calpain 2 in neural stem cell (NSC) self-renewal and differentiation. We found that calpain inhibition using either the chemical inhibitor calpeptin or the endogenous calpain inhibitor calpastatin favored differentiation of NSCs. This effect was associated with significant changes in cell cycle-related proteins and may be regulated by calcium. Interestingly, calpain 1 and calpain 2 were found to play distinct roles in NSC fate decision. Calpain 1 expression levels were higher in self-renewing NSC and decreased with differentiation, while calpain 2 increased throughout differentiation. In addition, calpain 1 silencing resulted in increased levels of both neuronal and glial markers, β-III Tubulin and glial fibrillary acidic protein (GFAP). Calpain 2 silencing elicited decreased levels of GFAP. These results support a role for calpain 1 in repressing differentiation, thus maintaining a proliferative NSC pool, and suggest that calpain 2 is involved in glial differentiation

    Experiência brasileira utilizando terapia sequencial de alta dose seguido de transplante autólogo de célula-tronco hematopoética para linfomas malignos

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    Using the overall survival (OS), disease free survival (DFS) and progression free survival (PFS), as well as associated toxicity, the purpose of this work was to evaluate the effectiveness of HDS followed by ASCT as salvage therapy. A retrospective analysis was performed of 106 patients with high grade non-Hodgkin lymphoma receiving HDS followed by ASCT, between 1998 and 2006. Median age was 45 years (Range: 8-65), with 66 (62%) men. Histopathological classification was: 78% DLBCL patients, 12% T and anaplastic and 9% Mantle cell lymphomas; 87% had B cell and 12% T cell lymphomas; 83% were stage III-IV (Ann Arbor Staging), 63% had B symptoms, 32% had bone marrow involvement, 62% bulky disease and 42% high-intermediate or high risk IPI. After HDCY, 9 patients died, 7 from toxicity and 2 from sepsis. Eighty patients underwent ASCT, 47% were in complete remission (CR) and 15% died, all from toxicity. Their OS was 45% over 8 years. During the follow-up, another 35 patients died [4 CR, 1 partial response (PR), 2 relapsed disease (RD) and 28 disease progression (DP)], 11 (31%) had not performed ASCT. OS was 37%; DFS was 49% and PFS 28%. OS by diagnosis was 42% for DLBCL, 40% for T-cell (8 y) and 20% for Mantle Cell (6 y) (P=NS). OS by B symptom patients was 22% vs. 58% (P=0.002) and PFS was 23% vs. 37% (P=0.03). Patients who achieved CR after HDCY (38) had significantly better OS and PFS (38% and 17%) than patients who remained in DP (P<0.0001). Cox Regression demonstrated therapeutic lines before HDCY (Relative risk - RR = 1.41; CI 95%: 1.04-1.90; P= 0.02) and PD both before (RR = 2.70; CI 95%: 1.49-4.91, P<0.001) and after HDCY (RR = 5.38; 95% CI: 2.93-9.87; P<0.0001). Conclusions: Our study suggests HDS is an efficient treatment to improve status and to reduce tumoral burden. Regardless of toxicity-related mortality it is feasible, especially considering the poor prognosis of patients.A proposta deste trabalho foi avaliar a eficácia da HDS seguida do transplante autólogo como terapia de salvamento através da sobrevida global, livre de doença e livre de progressão bem como sua toxicidade. Realizou-se estudo retrospectivo com 106 pacientes com LNH de alto grau de malignidade entre 1998 e 2006. A mediana de idade foi 45 anos (8-65); 62% homens; DLBCL, 78%; 12%, T e anaplásico e 9%, linfoma da zona do manto; 87%, células B; 83% estádios III-IV; 63% com sintomas B; 32% com infiltração da medula óssea ao diagnóstico; 62% com grande massa e 42% com IPI de alto risco ou intermediário. Após alta dose de ciclofosfamida (HDCY), nove pacientes faleceram. Oitenta pacientes realizaram o transplante, sendo que 47% estavam em RC e 15% faleceram devido à toxicidade. A sobrevida global foi de 45% em oito anos para estes pacientes. Trinta e cinco pacientes não realizaram o transplante por causas diversas. Sobrevida global para todos os pacientes foi de 42%, DLBCL, 40%; T-cell, 40% e zona do manto, 20% (P=NS). Pacientes que obtiveram RC após HDCY tiveram melhor sobrevida global e livre de progressão (38% e 17%, respectivamente) do que os que permaneceram em PD (P<0.0001). O modelo de Cox resultou que o número de linhas terapêuticas antes da HDCY (RR 1.41 IC 95%: 1.04-1.90, P=0.02) e PD antes da HDCY (RR 2.70, IC 95%: 1.49-4.91, P<0.001) e após HDCY (RR 5.38, IC 95%: 2.93-9.87, P<0.0001). Nosso estudo sugere que HDS é um método eficiente de tratamento para melhorar o status e reduzir a massa tumoral. Em relação à toxicidade, é factível, especialmente em pacientes de prognóstico ruim91
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