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Search Results: 1 - 10 of 87763 matches for " I. Arcavi "
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Trypanosoma cruzi en el líquido cefalorraquídeo de un paciente con SIDA
C. I. Menghi,C. L. Gatta,M. Arcavi
Revista argentina de microbiolog?-a , 2010,
Abstract:
The Flavours of SN II Light Curves
Iair Arcavi
Physics , 2012, DOI: 10.1017/S1743921312012653
Abstract: We present R-Band light curves of Type II supernovae (SNe) from the Caltech Core Collapse Program (CCCP). With the exception of interacting (Type IIn) SNe and rare events with long rise times, we find that most light curve shapes belong to one of three distinct classes: plateau, slowly declining and rapidly declining events. The latter class is composed solely of Type IIb SNe which present similar light curve shapes to those of SNe Ib, suggesting, perhaps, similar progenitor channels. We do not find any intermediate light curves, implying that these subclasses are unlikely to reflect variance of continuous parameters, but rather might result from physically distinct progenitor systems, strengthening the suggestion of a binary origin for at least some stripped SNe. We find a large plateau luminosity range for SNe IIP, while the plateau lengths seem rather uniform at approximately 100 days. We present also host galaxy trends from the Palomar Transient Factory (PTF) core collapse SN sample, which augment some of the photometric results.
Prevalencia de anticuerpos anti envoltura nuclear y sus isotipos en sueros positivos para anticuerpos antinucleares
Arcavi,Miriam; Orfus,Gladys;
Medicina (Buenos Aires) , 2006,
Abstract: antinuclear antibodies detected in hep-2 cells by indirect immunofluorescence assay display a great variety of images, including the nuclear envelope pattern. this is quite a less frequent finding. two thousand five hundred and ninety-four sera were processed, and 37.6% of ana were detected. the prevalence of anti-nuclear envelope antibodies (anea) was of 1.2%, with a high association with autoimmune liver diseases (83%) and a low association with systemic lupus erythematosus. in 21 sera of patients with anea, no anti-dnan antibodies were found; but 28.6% of anti-smooth muscle antibodies and 19% of anti-mitochondrial antibodies were detected. the triple rodent tissue section proved to be a less sensitive substrate than hep-2 for the detection of anea. when using conjugates against different isotypes of antibodies for the detection of ana, 90.5% of igg, 66.6% of iga and 9.5% of igm. two patients had anea-iga at high titers (31:160) without anea-igg. in this work, the importance of performing complementary tests for the detection of anti-smooth muscle antibodies, anti-mitochondrial antibodies and anti-dnan is highlighted in order to apply these tests as guidelines for the clinical diagnosis of patients with anea. besides, this study expresses the need of using total anti-ig antibodies as conjugate for iif-hep-2 instead of anti-igg; until the role of iga antibodies in these autoimmune diseases is clarified.
Anticuerpos antinucleares, imágenes y características obtenidas por inmunofluorescencia: Importancia de los isotipos IgA, IgM e IgG
Arcavi,Miriam; Dadone,Jorge;
Medicina (Buenos Aires) , 2009,
Abstract: the indirect immunofluorescence with epitelial cell line from human laryngeal carcinoma as substrate (iif-hep2) and anti-igg or anti-total ig as antisera, is the technique currently used for the detection of antinuclear antibodies. the most important antibodies for the diagnosis and follow-up of connective tissue diseases (ctd) are the igg-ana, while the igm-ana have no clinical relevance. however the iga-ana have not been thoroughly investigated so far. the aim of this work was to study the prevalence of different ana isotypes of ig antibodies in ctd patients and to evaluate the convenience of the use of monovalent or polyvalent conjugate. we examined the sera of 100 patients with different ctd by iif-hep2 and detected a prevalence of 38% iga-ana (titles ≥ 1:80) and 12% igm-ana (titles ≤ 1:160). in twenty nine cases we detected iga-ana in absence of igm-ana, and in 3 cases igm-ana in absence of iga-ana. in all the cases igg-ana were present. in 6 sera a change in the immunofluorescence pattern was observed while using anti-iga conjugate, whereas in 3 the change was observed with the use of anti-igm conjugate. because of the high prevalence of ana-iga detected by iif-hep2, we emphasize the convenience of employing anti-total ig in spite of anti-igg conjugated until the role of ana-iga is dilucidated in ctd patients, in order to establish its relevance in the diagnosis, prognosis and follow-up of systemic rheumatic diseases.
Anticuerpos antinucleares, imágenes y características obtenidas por inmunofluorescencia: Importancia de los isotipos IgA, IgM e IgG Antinuclear antibodies, patterns and characteristics obtained by immunofluorescence: The importance of the IgA, IgM and IgG isotypes
Miriam Arcavi,Jorge Dadone
Medicina (Buenos Aires) , 2009,
Abstract: La técnica de elección para el screening de anticuerpos antinucleares (ANA) es la inmunofluorescencia indirecta que utiliza como sustrato una línea de células epiteliales de carcinoma de laringe humano (IFI-HEp2), y como antisuero, anti-IgG o anti-Ig totales. Los ANA-IgG son los más importantes para el diagnóstico y monitoreo de las enfermedades del tejido conectivo (ETC), mientras los ANA-IgM son de menor relevancia clínica en estos pacientes. Sin embargo, poco se sabe de los ANA-IgA ya que estos Ac han sido menos investigados. El objetivo de este trabajo fue estudiar la prevalencia de los diferentes isotipos de inmunoglobulinas de anticuerpos antinucleares en los pacientes con ETC y evaluar la conveniencia de utilizar conjugados monovalentes o polivalentes. Se procesaron 100 sueros de pacientes con diversas ETC empleando IFI-HEp2, en los cuales se detectó 38% de ANA-IgA (títulos ≥ 1:80) y 12% de ANA-IgM (títulos ≤ 1:160). En 29 casos se detectó IgA en ausencia de IgM, en 3 casos IgM en ausencia de IgA. En todos los casos los ANA-IgG estuvieron presentes. En 6 sueros se observó un cambio de imagen con conjugado anti-IgA y en 3 con conjugado anti-IgM. Debido a la alta prevalencia de ANA-IgA detectada por IFI-HEp2, se destaca la conveniencia de utilizar conjugado anti-Ig totales en lugar de anti-IgG, mientras se desconozca la relevancia de los ANA-IgA en el diagnóstico, pronóstico y seguimiento de las enfermedades reumáticas sistémicas. The indirect immunofluorescence with epitelial cell line from human laryngeal carcinoma as substrate (IIF-HEp2) and anti-IgG or anti-total Ig as antisera, is the technique currently used for the detection of antinuclear antibodies. The most important antibodies for the diagnosis and follow-up of connective tissue diseases (CTD) are the IgG-ANA, while the IgM-ANA have no clinical relevance. However the IgA-ANA have not been thoroughly investigated so far. The aim of this work was to study the prevalence of different ANA isotypes of Ig antibodies in CTD patients and to evaluate the convenience of the use of monovalent or polyvalent conjugate. We examined the sera of 100 patients with different CTD by IIF-HEp2 and detected a prevalence of 38% IgA-ANA (titles ≥ 1:80) and 12% IgM-ANA (titles ≤ 1:160). In twenty nine cases we detected IgA-ANA in absence of IgM-ANA, and in 3 cases IgM-ANA in absence of IgA-ANA. In all the cases IgG-ANA were present. In 6 sera a change in the immunofluorescence pattern was observed while using anti-IgA conjugate, whereas in 3 the change was observed with the use of anti-IgM conjugate. Because of
Prevalencia de anticuerpos anti envoltura nuclear y sus isotipos en sueros positivos para anticuerpos antinucleares Prevalence of antinuclear envelope antibodies and their isotypes in sera positive for antinuclear antibodies
Miriam Arcavi,Gladys Orfus
Medicina (Buenos Aires) , 2006,
Abstract: Los anticuerpos antinucleares detectados por inmunofluorescencia indirecta en células HEp-2 presentan una gran variedad de imágenes, entre ellas el patrón de envoltura nuclear que suele ser un hallazgo poco frecuente. Se procesaron 2594 sueros en los cuales se detectó un 37.6% de anticuerpos antinucleares. La prevalencia de anticuerpos anti-envoltura nuclear (ANEA) fue del 1.2% presentando una alta asociación con hepatopatías autoinmunes (83%) y baja con lupus eritematoso sistémico. En los 21 sueros de los pacientes que presentaron ANEA no se detectaron anticuerpos anti-ADNn hallándose 28.6% de anticuerpos anti-músculo liso y 19% de anticuerpos anti-mitocondriales. El corte triple de tejido de rata mostró ser un sustrato menos sensible que HEp-2 para la detección de ANEA. Al utilizar conjugados dirigidos contra diferentes isotipos de anticuerpos para la detección de ANEA, se encontró: 90.5% de IgG, 66.6% de IgA y 9.5% de IgM. Dos de los pacientes presentaron ANEA-IgA a altos títulos (31:160) en ausencia de ANEA-IgG. En este trabajo se destaca la importancia de realizar pruebas complementarias que detecten anticuerpos anti-músculo liso, anti-mitocondriales y anti-ADNn, para orientar el diagnóstico clínico de los pacientes que presentan ANEA. Además, sostiene la postura de utilizar como conjugado para IFI-HEp2 anticuerpos anti-inmunoglobulinas totales en lugar de anti-IgG hasta tanto se clarifique el rol que juegan los anticuerpos IgA en estas enfermedades autoimunes. Antinuclear antibodies detected in HEp-2 cells by indirect immunofluorescence assay display a great variety of images, including the nuclear envelope pattern. This is quite a less frequent finding. Two thousand five hundred and ninety-four sera were processed, and 37.6% of ANA were detected. The prevalence of anti-nuclear envelope antibodies (ANEA) was of 1.2%, with a high association with autoimmune liver diseases (83%) and a low association with systemic lupus erythematosus. In 21 sera of patients with ANEA, no anti-DNAn antibodies were found; but 28.6% of anti-smooth muscle antibodies and 19% of anti-mitochondrial antibodies were detected. The triple rodent tissue section proved to be a less sensitive substrate than HEp-2 for the detection of ANEA. When using conjugates against different isotypes of antibodies for the detection of ANA, 90.5% of IgG, 66.6% of IgA and 9.5% of IgM. Two patients had ANEA-IgA at high titers (31:160) without ANEA-IgG. In this work, the importance of performing complementary tests for the detection of anti-smooth muscle antibodies, anti-mitochondrial antibodies
Did the progenitor of SN2011dh have a binary companion?
J. R. Maund,I. Arcavi,M. Ergon,J. J. Eldridge,C. Georgy,S. B. Cenko,A. Horesh,R. G. Izzard,R. J. Stancliffe
Physics , 2015, DOI: 10.1093/mnras/stv2098
Abstract: We present late-time Hubble Space Telescope (HST) ultraviolet (UV) and optical observations of the site of SN 2011dh in the galaxy M51, ~1164 days post-explosion. At the SN location, we observe a point source that is visible at all wavelengths, that is significantly fainter than the spectral energy distribution (SED) of the Yellow Supergiant progenitor observed prior to explosion. The previously reported photometry of the progenitor is, therefore, completely unaffected by any sources that may persist at the SN location after explosion. In comparison with the previously reported late-time photometric evolution of SN 2011dh, we find that the light curve has plateaued at all wavelengths. The SED of the late-time source is clearly inconsistent with a SED of stellar origin. Although the SED is bright at UV wavelengths, there is no strong evidence that the late-time luminosity originates solely from a stellar source corresponding to the binary companion, although a partial contribution to the observed UV flux from a companion star can not be ruled out.
El laboratorio en distintos estadios de la enfermedad de Chagas
Arcavi,Miriam; Biassotti,Alicia; Pandolfo,Marcela;
Acta bioqu?-mica cl?-nica latinoamericana , 2005,
Abstract: around 20 to 30% of chagas infected people will suffer from cardiac problems. the aim of this work was to evaluate if c reactive protein (crp), parasitemia and/or high titters of specific antibodies could predict risk of cardiac disease. the study was performed in two capital federal centers: hospital de clínicas"josé de san martin" and hospital"josé maría penna". 100 patients were selected, 70 of them were in the chronic stage of the disease, with more than 15 years of evolution and were positive for two or three serological chagas techniques. the patients were divided into three groups, a) group i: 40 patients in the indeterminate stage (asymptomatic), b) group ii: 21 patients with cardiopathy a (arrhythmias and/or conduction disorders), c) group iii: 9 patients with cardiopathy b (cardiomegaly and congestive insufficiency). 65% of patients in group i presented high titters of indirect hemaglutination (>1/256). this result reveals the necessity of performing a prospective study to evaluate whether this finding is related to the onset of cardiac symptoms or not. even though cardiac damage could be explained as an inflammatory process where cardiac mononuclear cells are infiltrated by parasites (probable effectors of tissue damage), there was no correlation found between cardiac alteration and serum levels of crp, parasitemia or high levels of specific antibodies.
El laboratorio en distintos estadios de la enfermedad de Chagas The laboratory in different stages of chagas disease
Miriam Arcavi,Alicia Biassotti,Marcela Pandolfo
Acta bioqu?-mica cl?-nica latinoamericana , 2005,
Abstract: Aproximadamente del 20% al 30% de los infectados chagásicos presentan compromiso cardíaco. El objetivo de este trabajo consistió en evaluar si la concentración de proteína C reactiva (PCR), parasitemia y/o títulos elevados de anticuerpos específicos podrían predecir riesgo de enfermedad. Se realizó un estudio en dos centros asistenciales de la Capital Federal: Hospital de Clínicas"José de San Martín" y Hospital"José María Penna" donde se seleccionaron 100 pacientes de los cuales 70 eran chagásicos crónicos con mas de 15 a os de evolución, que presentaron dos o tres técnicas serológicas reactivas para Chagas. Se los dividió en tres grupos, a) Grupo I: 40 pacientes en etapa indeterminada (asintomáticos), b) Grupo II: 21 pacientes con cardiopatía A (arritmias y/o trastornos de conducción), c) Grupo III: 9 pacientes con cardiopatía B (cardiomegalia e insuficiencia congestiva). El 65% de los pacientes del grupo I presentaron títulos elevados de hemaglutinación indirecta (> 1/256). Este resultado indica la importancia de realizar un estudio prospectivo para evaluar si este hallazgo guarda relación con el inicio de los síntomas. Si bien el da o cardíaco podría explicarse como un proceso inflamatorio donde las células mononucleares del corazón estarían infiltradas por los parásitos (probables efectores del da o tisular), no se encontró correlación entre compromiso cardiaco y niveles séricos de PCR, presencia de parasitemia o títulos elevados de anticuerpos específicos. Around 20 to 30% of Chagas infected people will suffer from cardiac problems. The aim of this work was to evaluate if C Reactive Protein (CRP), parasitemia and/or high titters of specific antibodies could predict risk of cardiac disease. The study was performed in two Capital Federal centers: Hospital de Clínicas"José de San Martin" and Hospital"José María Penna". 100 patients were selected, 70 of them were in the chronic stage of the disease, with more than 15 years of evolution and were positive for two or three serological Chagas techniques. The patients were divided into three groups, a) Group I: 40 patients in the indeterminate stage (asymptomatic), b) Group II: 21 patients with cardiopathy A (arrhythmias and/or conduction disorders), c) Group III: 9 patients with cardiopathy B (cardiomegaly and congestive insufficiency). 65% of patients in Group I presented high titters of indirect hemaglutination (>1/256). This result reveals the necessity of performing a prospective study to evaluate whether this finding is related to the onset of cardiac symptoms or not. Even though cardiac damage could
The first month of evolution of the slow rising type II-P SN 2013ej in M74
S. Valenti,D. Sand,A. Pastorello,M. L. Graham,D. A. Howell,J. Parrent,L. Tomasella,P. Ochner,M. Fraser,S. Benetti,F. Yuan,S. J. Smartt,J. R. Maund,I. Arcavi,A. Gal-Yam,C. Inserra,D. Young
Physics , 2013, DOI: 10.1093/mnrasl/slt171
Abstract: We present early photometric and spectroscopic observations of SN 2013ej, a bright type IIP supernova in M74. SN 2013ej is one of the closest SNe ever discovered. The available archive images and the early discovery help to constrain the nature of its progenitor. The earliest detection of this explosion was on 2013 July 24.14 UT and our spectroscopic monitoring began on July 27.73 UT, continuing almost daily for two weeks with the LCOGT FLOYDS spectrographs. Daily optical photometric monitoring was achieved with the LCOGT 1m network, and were complemented by UV data from SWIFT and near-infrared spectra from PESSTO and IRTF. The data from our monitoring campaign show that SN 2013ej experienced a 10-day rise before entering into a well defined plateau phase. This unusually long rise time for a type IIP has been seen previously in SN 2006bp and SN 2009bw. A relatively rare strong absorption blue-ward of H{\alpha} is present since our earliest spectrum. We identify this feature as Si ii, rather than high velocity H{\alpha} as sometimes reported in the literature.
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