608 research outputs found

    Test of Universality in Anisotropic 3D Ising Model

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    Chen and Dohm predicted theoretically in 2004 that the widely believed universality principle is violated in the Ising model on the simple cubic lattice with more than only six nearest neighbours. Schulte and Drope by Monte Carlo simulations found such violation, but not in the predicted direction. Selke and Shchur tested the square lattice. Here we check only this universality for the susceptibility ratio near the critical point. For this purpose we study first the standard Ising model on a simple cubic lattice with six nearest neighbours, then with six nearest and twelve next-nearest neighbours, and compare the results with the Chen-Dohm lattice of six nearest neighbours and only half of the twelve next-nearest neighbours. We do not confirm the violation of universality found by Schulte and Drope in the susceptibility ratio.Comment: 6 pages including 4 figures, Physica A, in pres

    Immunophenotypic characterization of normal blood CD56+lo versus CD56+hi NK‐cell subsets and its impact on the understanding of their tissue distribution and functional properties

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    Blood Cells Mol Dis. 2001 Jul-Aug;27(4):731-43. Immunophenotypic characterization of normal blood CD56+lo versus CD56+hi NK-cell subsets and its impact on the understanding of their tissue distribution and functional properties. Lima M, Teixeira MA, Queirós ML, Leite M, Santos AH, Justiça B, Orfão A. Service of Clinical Hematology, Unit of Cytometry, Hospital Geral de Santo António, Porto, Portugal. [email protected] Abstract In the present study we have compared the immunophenotypic characteristics of the CD56+lo and CD56+hi NK-cell subsets in a group of normal healthy adults. Our results show that CD56+hi NK-cells display greater light-scatter properties than CD56+lo NK-cells at the same time they have higher levels of CD25 and CD122 IL-2 chains, together with a higher reactivity for HLA-DR and CD45RO and lower levels of CD45RA, supporting that, as opposed to the majority of the CD56+lo population, CD56+hi NK-cells might correspond to a subset of activated circulating NK-lymphocytes. Higher expression of the CD2 and CD7 costimulatory molecules found for the CD56+hi NK-cells would support their greater ability to respond to various stimuli. In addition, CD56+hi NK-cells expressed higher levels of several adhesion molecules such as CD2, CD11c, CD44, CD56, and CD62L compared to CD56+lo NK-cells, supporting a particular ability of these cells to migrate from blood to tissues and/or a potential advantage to form conjugates with target cells. Interestingly, CD56+lo and CD56+hi NK-cells showed a different pattern of expression of killer receptors that might determine different activation requirements for each of these NK-cell subsets. For instance, absence or low levels of CD16 expression might explain the lower antibody-dependent cytotoxicity activity of CD56+hi NK-cells. On the other hand, the virtual absence of expression of the CD158a and NKB1 immunoglobulin-like and the greater reactivity for the CD94 lectin-like killer receptors on CD56+hi in comparison to CD56+lo NK-cells might determine different MHC-class I specificities for both NK-cell subsets, a possibility that deserves further studies to be confirmed. PMID: 11778657 [PubMed - indexed for MEDLINE

    Reactive phenotypes after acute and chronic NK‐cell activation

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    J Biol Regul Homeost Agents. 2004 Jul-Dec;18(3-4):331-4. Reactive phenotypes after acute and chronic NK-cell activation. Lima M, Almeida J, Teixeira MA, Santos AH, Queirós ML, Fonseca S, Moura J, Gonçalves M, Orfão A, Pinto Ribeiro AC. Service of Clinical Hematology, Laboratory of Cytometry, Hospital Geral de Santo António, Porto, Portugal. [email protected] Abstract Several phenotypic changes have been shown to occur after NK-cell stimulation, involving molecules that have been proved to regulate NK-cell migration into tissues and NK-cell activation and proliferation as well as target cell recognition and killing. Here, we review the reactive phenotypes observed in vivo after acute and chronic NK-cell activation. PMID: 15786700 [PubMed - indexed for MEDLINE

    Immunophenotype and TCR‐Vbeta repertoire of peripheral blood T‐cells in acute infectious mononucleosis.

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    Blood Cells Mol Dis. 2003 Jan-Feb;30(1):1-12. Immunophenotype and TCR-Vbeta repertoire of peripheral blood T-cells in acute infectious mononucleosis. Lima M, Teixeira Mdos A, Queirós ML, Santos AH, Gonçalves C, Correia J, Farinha F, Mendonça F, Soares JM, Almeida J, Orfão A, Justiça B. Service of Clinical Haematology, Hospital Santo António, Porto, Portugal. [email protected] Abstract Although a number of studies on the phenotypic changes that occur after T-cell activation have already been published, the specific immunophenotypic features of T-lymphocytes and the frequency at which TCR-variable region (TCR-V) restricted T-cell expansions occur "in vivo" during acute viral infection still remains to be established. We report on the immunophenotype and TCR-V repertoire of peripheral blood T-cells from 28 patients with acute infectious mononucleosis. Immunophenotypic studies were performed by flow cytometry using direct immunofluorescence techniques and stain-and-then-lyse sample preparation protocols with three- and four-colour combinations of monoclonal antibodies directed against a large panel of T- and NK-cell associated markers, activation- and adhesion-related molecules and TCR-Vbeta, -Vgamma and -Vdelta families. Nearly all patients (27/28) showed a massive expansion of CD8(+)/TCRalphabeta(+) T cells, the majority (>90%) of which displayed an immunophenotype compatible with T-cell activation: CD2(+high), CD7(+low), CD11a(+high), CD38(+high), HLA-DR(+high), CD28(+/-low), CD45RO(+high), CD45RA(-/+low), CD11b(-/+low), CD11c(+/-low), CD16(-), CD56(-), CD57(-), CD62L(-), CD94(-), CD158a(-), CD161(-), NKB1(-). Additionally, the levels of both CD3 and CD5 were slightly decreased compared to those found in normal individuals. Late-activation antigens, such as CD57, were found in small proportions of CD8(+)/TCRalphabeta(+) T-cells. Increased numbers of CD4(+)/TCRalphabeta(+) T-cells, TCRgammadelta(+) T-cells and NK-cells were also noticed in 17, 16 and 13 of the 28 cases studied, respectively. Evidence for activation of CD4(+)/TCRalphabeta(+) and TCRgammadelta(+) T-cells relied on changes similar to those described for CD8(+)/TCRalphabeta(+) although less pronounced, except for higher levels of both CD5 and CD28 in the absence of reactivity for CD11c on CD4(+)/TCRalphabeta(+) T-cells and higher levels of CD161 and CD94 on TCRgammadelta(+) T-cells. Small expansions of one or more TCR-Vbeta families accounting for 12 +/- 7% of either the CD8(+)/TCRalphabeta(+) or the CD4(+)/TCRalphabeta(+) T-cell compartment were found in 12 of 14 patients studied, whereas the distribution of the TCR-Vgamma and -Vdelta repertoires tested in 2 of the individuals with expanded TCRgammadelta(+) T-cells was similar to that observed in control individuals. The results presented here provide evidence for an extensive T-cell activation during acute viral infection and establish the immunophenotype patterns associated with this condition. PMID: 12667982 [PubMed - indexed for MEDLINE

    Prevalence of antibodies against Chlamydophila spp. in herds with bovine abortion of Paraná state, Brazil

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    Chlamydophila abortus é o agente etiológico do aborto epizoótico bovino, cujas manifestações clínicas mais freqüentes são aborto, nascimento de bezerros prematuros e de animais fracos, natimorto e repetição de cio em intervalos irregulares. O objetivo deste trabalho foi estimar a prevalência de anticorpos anti-Chlamydophila spp. em fêmeas bovinas de propriedades rurais com histórico de aborto, selecionadas dentro do delineamento amostral do Plano Nacional de Controle e Erradicação da Brucelose e Tuberculose no estado do Paraná. Foram testadas pela prova de fixação de complemento 3.102 amostras de soro de fêmeas bovinas (idade > 24 meses), provenientes de 373 propriedades. Ao total, 44 (1,42%) animais foram positivos com títulos > 32. A prevalência de focos foi de 8,82% (6,15%-12,17%). Animais confinados ou semi-confinados (OR=3.339, P=0.004), propriedade com menos de 35 matrizes (OR=3.339, P=0.017), presença de produtos do aborto na pastagem (OR=2.372, P=0.037) e aluguel de pasto (OR=3.398, P=0.006) foram considerados fatores de risco para Chlamydophila spp. A infecção por Chlamydophila spp. acometeu um número pequeno de animais, oriundos de propriedades com histórico de aborto. A importância deste agente como causa de aborto em bovinos no estado do Paraná, se existir, é muito pequena.Chlamydophila abortus is a recognized cause of bovine epizootic abortion. Abortion, premature birth and weak lamb/calf, stillbirth and repeat breeding in irregular intervals are the most frequent disease manifestations. The complement fixation test is the recommended by the World Organization of Animal Health (OIE) for Chlamydophila spp. serologic diagnosis. The aim of this study was estimate the prevalence of antibodies against Chlamydophila spp. in cattle herds with abortion, selected inside the sampling design of National Program of Control and Erradication of Brucellosis in Paraná state. Serum samples of 3,102 cows (age > 24 months) from 373 herds were analyzed by complement fixation test. Totally, 44 (1.42%) animal were positive with titers > 32. The seroprevalence of Chlamydophila spp. in the herds was 8.82% (6.15%-12.17%). Four variables were associated with seroprevalence for Chlamydophila spp. in the final model of logistic regression: confined or semi-confined breeding (OR=3.339, P=0.004), farms with less than 35 cows (OR=3.339, P=0.017), abortion in the pasture (OR=2.372, P=0.037) and pasture rent (OR=3.398, P=0.006) were risk factors for Chlamydophila spp. This bacterium infected a small number of cattle from herds with abortion in Paraná state. Chlamydophila spp impact as abortion cause is reduced in this state

    Intraclonal diversity in a Sezary syndrome with a differential response to 2‐deoxycoformycin of the two lymphoma cell populations

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    Br J Haematol. 2002 Dec;119(3):629-33. Intraclonal diversity in a Sezary syndrome with a differential response to 2-deoxycoformycin of the two lymphoma cell populations. Granjo E, Lima M, Lopes JM, Cunha N, Teixeira Mdos A, Santos F, Candeias J, Resende C, Santos AH, Balanzategui A, Orfão A, Matutes E. Department of Clinical Haematology, Hospital Geral de São João, Porto, Portugal. [email protected] Abstract We report a case of Sezary syndrome with two abnormal CD4+ T-cell populations detected in the peripheral blood by flow cytometry immunophenotyping and DNA cell content, suggesting a biclonal T-cell lymphoproliferative disorder. Despite these findings, molecular analysis of the T-cell receptor genes was consistent with a monoclonal T-cell proliferation, supporting the existence of intraclonal diversity rather than a true biclonal disease. The patient achieved a transient response with 2-deoxycoformycin, with a selective decrease of the larger/hyperploid T-cell population; later on, an increased representation of this T-cell population was observed concomitantly with clinical relapse. PMID: 12437636 [PubMed - indexed for MEDLINE

    High-redshift objects and the generalized Chaplygin gas

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    Motivated by recent developments in particle physics and cosmology, there has been growing interest in an unified description of dark matter and dark energy scenarios. In this paper we explore observational constraints from age estimates of high-zz objects on cosmological models dominated by an exotic fluid with equation of state p=A/ραp = -A/\rho^{\alpha} (the so-called generalized Chaplygin gas) which has the interesting feature of interpolating between non-relativistic matter and negative-pressure dark energy regimes. As a general result we find that, if the age estimates of these objects are correct, they impose very restrictive limits on some of these scenarios.Comment: 5 pages, 3 figures, to appear in Phys. Rev.

    Guess what: Chronic 13q14.3+/CD5‐ /CD23+ lymphocytic leukemia in blood and t(11;14)(q13;q32)+/CD5+/CD23‐ mantle cell lymphoma in lymph nodes!

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    Cytometry B Clin Cytom. 2003 Jan;51(1):41-4. Guess what: Chronic 13q14.3+/CD5-/CD23+ lymphocytic leukemia in blood and t(11;14)(q13;q32)+/CD5+/CD23- mantle cell lymphoma in lymph nodes! Lima M, Pinto L, Dos Anjos Teixeira M, Canelhas A, Mota A, Cabeda JM, Silva C, Queirós ML, Fonseca S, Santos AH, Brochado P, Justiça B. Service of Clinical Hematology, Hospital Geral de Santo António, Porto, Portugal. [email protected] Abstract We report a case of a patient with two B-cell lymphoproliferative disorders: CD5(-)/CD23(+) B-cell chronic lymphocytic leukemia and CD5(+)/CD23(-) mantle cell lymphoma. These disorders were diagnosed simultaneously based on flow cytometry, immunohistochemistry, fluorescence in situ hybridization, and polymerase chain reaction-based molecular studies. The B-cell lymphocytic leukemia clone predominated in the blood and bone marrow, whereas the mantle cell clone predominated in lymph nodes. Copyright 2002 Wiley-Liss, Inc. PMID: 12500296 [PubMed - indexed for MEDLINE

    Selenium tolerance, accumulation, localization and speciation in a Cardamine hyperaccumulator and a non-hyperaccumulator

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    Cardamine violifolia (family Brassicaceae) is the first discovered selenium hyperaccumulator from the genus Cardamine with unique properties in terms of selenium accumulation, i.e., high abundance of selenolanthionine. In our study, a fully comprehensive experiment was conducted with the comparison of a non-hyperaccumulator Cardamine species, Cardamine pratensis, covering growth characteristics, chlorophyll fluorescence, spatial selenium/sulfur distribution patterns through elemental analyses (synchrotron-based X-Ray Fluorescence and ICP-OES) and speciation data through selenium K-edge micro X-ray absorption near-edge structure analysis (μXANES) and strong cation exchange (SCX)-ICP-MS. The results revealed remarkable differences in contrast to other selenium hyperaccumulators as neither Cardamine species showed evidence of growth stimulation by selenium. Also, selenite uptake was not inhibited by phosphate for either of the Cardamine species. Sulfate inhibited selenate uptake, but the two Cardamine species did not show any difference in this respect. However, μXRF derived speciation maps and selenium/sulfur uptake characteristics provided results that are similar to other formerly reported hyperaccumulator and non-hyperaccumulator Brassicaceae species. μXANES showed organic selenium, "C-Se-C", in seedlings of both species and also in mature C. violifolia plants. In contrast, selenate-supplied mature C. pratensis contained approximately half "C-Se-C" and half selenate. SCX-ICP-MS data showed evidence of the lack of selenocystine in any of the Cardamine plant extracts. Thus, C. violifolia shows clear selenium-related physiological and biochemical differences compared to C. pratensis and other selenium hyperaccumulators
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