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Texto completo SciELO Chile
Texto completo
Id: lil-571988
Autor: Berríos, Soledad; Manterola, Marcia; Prieto, Zulita; López-Fenner, Julio; Page, Jesús; Fernández-Donoso, Raúl.
Título: Model of chromosome associations in Mus domesticus spermatocytes
Fonte: Biol. Res;43(3):275-285, 2010. ilus, graf, tab.
Idioma: en.
Projeto: FONDECYT; . Agencia Española de Cooperación Internacional para el Desarrollo (Spain).
Resumo: Understanding the spatial organization of the chromosomes in meiotic nuclei is crucial to our knowledge of the genome's functional regulation, stability and evolution. This study examined the nuclear architecture of Mus domesticus 2n=40 pachytene spermatocytes, analyzing the associations among autosomal bivalents via their Centromere Telomere Complexes (CTC). The study developed a nuclear model in which each CTC was represented as a 3D computer object. The probability of a given combination of associations among CTC was estimated by simulating a random distribution of 19 indistinguishable CTC over n indistinguishable "cells" on the nuclear envelope. The estimated association frequencies resulting from this numerical approach were similar to those obtained by quantifying actual associations in pachytene spermatocyte spreads. The nuclear localization and associations of CTC through the meiotic prophase in well-preserved nuclei were also analyzed. We concluded that throughout the meiotic prophase: 1) the CTC of autosomal bivalents are not randomly distributed in the nuclear space; 2) the CTC associate amongst themselves, probably at random, over a small surface of the nuclear envelope, at the beginning of the meiotic prophase; 3) the initial aggregation of centromere regions occurring in lepto-zygotene likely resolves into several smaller aggregates according to patterns of preferential partitioning; 4) these smaller aggregates spread over the inner face of the nuclear envelope, remaining stable until advanced stages of the meiotic prophase or even until the first meiotic division.
Descritores: Núcleo Celular/ultraestrutura
Cromossomos de Mamíferos/ultraestrutura
Espermatócitos/ultraestrutura
-Centrômero/ultraestrutura
Modelos Biológicos
Prófase Meiótica I/fisiologia
Membrana Nuclear/ultraestrutura
Telômero/ultraestrutura
Limites: Animais
Masculino
Camundongos
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: CL1.1 - Biblioteca Central


  2 / 10 LILACS  
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Texto completo SciELO Venezuela
Texto completo
Id: lil-518688
Autor: González-Mujica, Freddy.
Título: Glucosa-6-fosfatasa de envoltura nuclear de hígado de rata / Glucose-6-phosphatase from nuclear envelope in rat liver
Fonte: Invest. clín;49(2):169-180, jun. 2008. tab.
Idioma: es.
Resumo: Se comparó la actividad de la glucosa-6-fosfatasa (G-6-Pasa) de envoltura nuclear (EN) con la microsomal. Los microsomas intactos fueron incapaces de hidrolizar manosa-6-fosfato (M-6-P); por el contrario, la EN intacta fue capaz de hidrolizar dicho substrato. La galactosa-6-fosfato mostró ser un buen substrato tanto para la enzima de EN como microsomal, con una latencia similar a la obtenida para M-6-P utilizando microsomas, por lo cual galactosa-6-fosfato fue usado para medir el porcentaje de EN intactas. Los parámetros cinéticos (Kii y Kis) de la inhibición por floricina de la G-6-Pasa de EN intactas, utilizando glucosa-6-fosfato (G-6-P) y M-6-P como substrato, fueron aproximadamente iguales. El transportador T1 de EN fue más sensible a la amiloride que el microsomal. Por el contrario, el sistema microsomal fue más sensible al efecto de N-etilmaleimida (NEM) que el de EN y este último, fue prácticamente insensible a los inhibidores de transporte aniónico DIDS y SITS, los cuales afectan fuertemente la enzima microsomal. Los resultados anteriores permiten sugerir que en la EN existe un transportador de hexosas-6-fosfato, capaz de transportar G-6-P y M-6-P y quizás otras hexosas-6-fosfato y que, o es diferente al T1 microsomal, o si es igual es influenciado por las características del sistema membranoso en el cual está incluido. La capacidad superior de hidrólisis de PPi de la G-6-Pasa de EN intacta, en comparación con la de microsomas intactos, sugiere diferencias en el transportador de Pi/PPi (T2) de ambos sistemas. La menor sensibilidad de la G-6-Pasa de EN al NEM sugiere que la subunidad catalítica de este sistema también podría tener algunas diferencias con la isoforma microsomal.
Descritores: GLUCOSA-ABDOMEN, ACUTE-FOSFATASA
Microssomos
Membrana Nuclear
Florizina
-Bioquímica
Limites: Animais
Ratos
Tipo de Publ: Estudo Comparativo
Revisão
Responsável: VE1.1 - Biblioteca Humberto Garcia Arocha


  3 / 10 LILACS  
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Id: lil-449013
Autor: Arcavi, M; Orfus, G.
Título: 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
Fonte: Medicina (B.Aires);66(4):327-331, 2006. tab, ilus.
Idioma: es.
Resumo: 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 (> or = 1:160) 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-lgG; until the role of IgA antibodies in these autoimmune diseases is clarified.
Descritores: Anticorpos Antinucleares/sangue
Isotipos de Imunoglobulinas
Membrana Nuclear
-Anticorpos Antinucleares/imunologia
Células Epiteliais/imunologia
Técnica Indireta de Fluorescência para Anticorpo
Isotipos de Imunoglobulinas
Lâmina Nuclear/imunologia
Modelos Animais
Poro Nuclear/imunologia
Limites: Animais
Ratos
Humanos
Responsável: BR1.1 - BIREME


  4 / 10 LILACS  
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Fotocópia
Id: lil-384237
Autor: Solari, A. J; Rahn, M. I; Saura, A; Lujan, H. D.
Título: A unique mechanism of nuclear division in Giardia lamblia involves components of the ventral disk and the nuclear envelope
Fonte: Biocell;27(3):329-346, Dec. 2003.
Idioma: en.
Resumo: The fine structure of the binucleate, parasitic protist Giardia lamblia during interphase and divisional stages was studied by serial thin sectioning and three-dimensional reconstructions. The earlier sign of nuclear division is the development of a few peripheral areas of densely packed chromatin directly attached to the inner nuclear envelope. An intracytoplasmic sheet of ventral disk components grows from the cell periphery towards one of the nuclei, apparently constricting this nucleus, which becomes located at a ventral bulge. After the basal bodies become duplicated, a full nuclear division occurs in trophozoites, giving two pairs of parent-daughter nuclei. This full division occurs in a dorsal-ventral direction, with the resulting nuclear pairs located at the sides of the two sets of basal bodies. A new ventral disk is formed from the disk-derived sheets in the cell harboring the four nuclei. Cytokinesis is polymorphic, but at early stages is dorsal-to-dorsal. Encysting trophozoites show the development of Golgi cisternae stacks and dense, specific secretory granules. 3-D reconstructions show that cysts contain a single pair of incompletely strangled nuclei. The dividing Giardia lacks a typical, microtubular spindle either inside or outside the nuclei. The nuclear envelope seems to be the only structure involved in the final division of the parent-daughter nuclei.
Descritores: Giardia lamblia/ultraestrutura
Membrana Nuclear
Núcleo Celular/ultraestrutura
-Complexo de Golgi/fisiologia
Complexo de Golgi/ultraestrutura
Citoplasma/fisiologia
Citoplasma/ultraestrutura
Cromatina/fisiologia
Cromatina/ultraestrutura
Divisão Celular/fisiologia
Giardia lamblia/fisiologia
Microscopia Eletrônica
Membrana Nuclear
Núcleo Celular/fisiologia
Organelas/fisiologia
Organelas/ultraestrutura
Vesículas Secretórias/fisiologia
Vesículas Secretórias/ultraestrutura
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  5 / 10 LILACS  
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Texto completo SciELO Brasil
Texto completo
Id: lil-234885
Autor: Linden, R; Chiarini, L. B.
Título: Nuclear exclusion of transcription factors associated with apoptosis in developing nervous tissue
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;32(7):813-20, July 1999.
Idioma: en.
Conferência: Apresentado em: International Symposium on \"Signal Transduction and Gene Expression in Cell Proliferation and Differentiation\", 1, Säo Paulo, Aug. 31-Sept. 2, 1998.
Resumo: Programmed cell death in the form of apoptosis involves a network of metabolic events and may be triggered by a variety of stimuli in distinct cells. The nervous system contains several neuron and glial cell types, and developmental events are strongly dependent on selective cell interactions. Retinal explants have been used as a model to investigate apoptosis in nervous tissue. This preparation maintains the structural complexity and cell interactions similar to the retina in situ, and contains cells in all stages of development. We review the finding of nuclear exclusion of several transcription factors during apoptosis in retinal cells. The data reviewed in this paper suggest a link between apoptosis and a failure in the nucleo-cytoplasmic partition of transcription factors. It is argued that the nuclear exclusion of transcription factors may be an integral component of apoptosis both in the nervous system and in other types of cells and tissues
Descritores: Apoptose
Tecido Nervoso/crescimento & desenvolvimento
Retina/crescimento & desenvolvimento
Fatores de Transcrição/metabolismo
-Animais Recém-Nascidos
Diferenciação Celular
Tecido Nervoso/citologia
Tecido Nervoso/metabolismo
Membrana Nuclear/metabolismo
Retina/citologia
Retina/metabolismo
Limites: Animais
Ratos
Tipo de Publ: Revisão
Responsável: BR1.1 - BIREME


  6 / 10 LILACS  
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Id: lil-227319
Autor: Herrera Diosdado, Rosa María; Avalos Díaz, Esperanza; Herrera Esparza, Rafael.
Título: Las láminas nucleares y la cromatina, forman un complejo que es reconocido por una población de anticuerpos anti-DNA nativo / Anti-nDNA antibodies and cross-react with the laminar structures of the nucleus
Fonte: Rev. mex. reumatol;12(4):168-71, jul.-ago. 1997. tab, ilus.
Idioma: es.
Resumo: En el presente trabajo se determinó la afinidad de los anticuerpos anti-DNA por estructuras laminares del núcleo: para ésto se utilizaron sueros de pacientes con lupus que presentaban anticuerpos antinucleares con patrón anular y anti-DNAn. Se realizaron pruebas de fluorescencia en células digeridas con DNasa o con tripsina. La especificidad molecular se estableció por Western blot en extracto de células HEp-2. De 100 sueros probados, 16 resultaron con un patrón anular, siete resistieron la acción de la DNasa y reconocieron una proteína de 70 kDa correspondiente a lámina B. Los resultados de este estudio sugieren que la cromatina perinuclear se encuentra en íntima relación con proteínas de la envoltura nuclear y con las láminas, y que los anticuerpos anti-DNAn reconocen moléculas de ambas estructuras
Descritores: Anticorpos Antinucleares/ultraestrutura
Western Blotting
Cromatina
Fluorescência
Imunofluorescência
Lúpus Eritematoso Sistêmico
Membrana Nuclear
Proteínas Nucleares
Limites: Humanos
Responsável: MX1.1 - CENIDSP - Centro de Información para Decisiones en Salud Pública


  7 / 10 LILACS  
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Fotocópia
Id: lil-225379
Autor: Motta, Norma; Gonzalez-Mujica, Freddy; Márquez, Ana H.
Título: Thioacetamide effects on the polypeptidic and nucleoporin pattern and chemical composition of rat liver nuclear envelope subfractions
Fonte: Acta cient. venez;49(3):179-86, 1998. ilus, tab.
Idioma: en.
Resumo: The effect of the administration of seven doses of the hepatocarcinogen thioacetamide on the chemical composition of rat liver nuclear envelope subfractions: associated chromatin, nuclear membranes and pore complex-lamina fraction, is analyzed. No alteration in DNA, RNA or phospholipid content is observed after the hepatocarcinogen treatment. Electrophoretic studies of each subfraction from thioacetamide treated rats show differences in the relative proportions of some polypeptides when compared with the controls. Examination of the wheat germ agglutinin binding polypeptides of each subfraction reveals a decrease in the stain of two pore complex-lamina nucleoporins of 85 and 164 kDa and an increase in one of 93 kDa; this observation can be due to changes in the quantity and/or in the agglutinin binding capacity of the nucleoporin as a result of thioacetamide administration. In view of the participation of nucleoporins in the nucleocytoplasmic transport, the changes observed suggest a relationship between changes of some O-linked N-acetyl glucosamine polypeptides components of the nuclear pore complex and the altered transport of some RNA species observed after thioacetamide administration.
Descritores: Carcinógenos/farmacologia
Fígado/citologia
Proteínas Nucleares/efeitos dos fármacos
Peptídeos/efeitos dos fármacos
Tioacetamida/farmacologia
-Membrana Nuclear/química
Membrana Nuclear/metabolismo
Proteínas Nucleares/química
Peptídeos/química
Ratos Sprague-Dawley
Limites: Animais
Masculino
Ratos
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  8 / 10 LILACS  
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Texto completo SciELO Brasil
Varanda, W. A
Texto completo
Id: lil-212269
Autor: Bustamante, J. O; Varanda, W. A.
Título: Patch-clamp detection of macromolecular translation along nuclear pores
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;31(3):333-54, Mar. 1998. ilus, tab, graf.
Idioma: en.
Conferência: Apresentado em: Annual Meeting, 12, Caxambu, 27-30 Aug. 1997.
Resumo: The present paper reviews the application of patch-clamp principles to the detection and measurement of macromolecular translocation along the nuclear pores. We demonstrate that the tight-seal `gigaseal' between the pipette tip and the nuclear membrane is possible in the presence of fully operational nuclear pores. We show that the ability to form a gigaseal in nucleus-attached configurations does not mean that only the activity of channels from the outer membrane of the nuclear envelope can be detected. Instead, we show that, in the presence of fully operational nuclear pores, it is likely that the large-conductance ion channel activity recorded derives from the nuclear pores. We conclude the technical section with the suggestion that the best way to demonstrate that the nuclear pores are responsible for ion channel activity is by showing with fluorescence microscopy the nuclear translocation of ions and small molecules and the exclusion of the same from the cisterna enclosed by the two membranes of the envelope. Since transcription factors and mRNAs, two major groups of nuclear macromolecules, use nuclear pores to enter and exit the nucleus and play essential roles in the control of gene activity and expression, this review should be useful to cell and molecular biologists interested in understanding how patch-clamp can be used to quantitate the translocation of such macromolecules into and out of the nucleus.
Descritores: Canais Iônicos/metabolismo
Substâncias Macromoleculares
Membrana Nuclear/metabolismo
Técnicas de Patch-Clamp
-Transporte Biológico
Expressão Gênica/fisiologia
Tipo de Publ: Revisão
Responsável: BR1.1 - BIREME


  9 / 10 LILACS  
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Id: lil-78954
Autor: Inciarte, Haydee; González Mujica, Freddy.
Título: Efecto de la Tioacetamida sobre la envoltura nuclear de las células de la corteza renal de la rata / Thioacetamide effects on the nuclear envelope from rat kidney cortex
Fonte: Invest. clín;29(3):121-40, 1988. ilus, tab.
Idioma: es.
Resumo: Se determinó el efecto que produce la administración de Tioacetamida (TAA) sobre la composición y propiedades de los núcleos y envoltura nuclear (EN) purificados de la corteza renal (CR) de ratas, en relación a preparaciones obtenidas de animales controles a través de un método para la obtención de la EN, cuya pureza relativa fue analizada por microscopía electrónica y métodos enzimáticos. En la fracción nuclear de los animales tratados con TAA, se observaron las siguientes alteraciones: aumento en la concentración de RNA y fosfolípidos (pg/Núcleo) en un 77%, un leve incremento de DNA (pg/Núcleo) en un 17%. Por otro lado la concentración de proteínas (pg/Núcleo) permaneció constante. En la EN se encontró que la concentración de DNA disminuyó en un 68% y la de fosfolípidos en un 37%; en cambio la concentración de RNA aumentó discretamente en un 11%. Se encontraron importantes diferencias al estudiar el patrón polipeptídico obtenido al realizar electroforesis en geles de poliacrilamida de EN preparadas a partir de hígado y CR de ratas controles y tratadas con TAA. La actividad específica de la enzima glucosa-6-fosfatasa en los núcleos y EN de los animales tratados con TAA disminuyó en 54% y 43% respectivamente. En los estudios cinéticos se encontró que por efecto de la droga de la Vmax disminuyó significativamente sin alteración del Km. Se discuten las implicaciones de estos resultados
Descritores: Córtex Renal/efeitos dos fármacos
Membrana Nuclear/efeitos dos fármacos
Tioacetamida/efeitos adversos
-Microscopia Eletrônica/instrumentação
Limites: Ratos
Animais
Tipo de Publ: Estudo Comparativo
Responsável: VE1.1 - Biblioteca Humberto Garcia Arocha


  10 / 10 LILACS  
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Id: lil-27365
Autor: Duvilanski, Beatriz; Domínguez, Francisca E; Guglielmone, Alicia E. R. de; Krawiec, León.
Título: Effects of hypothyroidism and undernourishment on nuclear-cytoplasmic transport "in vitro"-of cerebral RNA
Fonte: Acta physiol. pharmacol. latinoam;35(3):301-10, 1985. tab.
Idioma: en.
Resumo: Efecto del hipotiroidismo y la malnutrición sobre el transporte núcelocitoplasmático de ARN "in vitro". La tiroidectomía neonatal produce en la rata de 10 días de edad modificaciones en la actividad específica del ARN "de marcación rápida", tanto a nivel nuclear como microsomal. La radiactividad del ARN ribosomal, cuya síntesis nuclear no es afectada por el hipotiroidismo, se ve disminuida a nivel microsomal, indicando retraso en el transporte a través de la membrana nucelar. La salida del ARN "de marcación rápida" desde el núcleo no se modifica bajo estas mismas condiciones. La mala nutrición produce cambios similares a los observados en el hipotiroidismo, excepto que la malnutrición, además, disminuye la liberación nuclear de mARN. Alteraciones a nivel de los factores citosólicos parecen ser la causa de la menor liberación nuclear del ARN ribosomal de cerebro de rata hipotiroidea, mientras que cambios en mecanismos intranucleares aún no conocidos serían los responsables de las modificaciones en el transporte de ARN ribosomal de cerebro de rata malnutrida
Descritores: Cérebro/metabolismo
Citosol/fisiologia
Hipotireoidismo/fisiopatologia
Desnutrição Proteico-Calórica/fisiopatologia
RNA/metabolismo
-Fracionamento Celular
Hormônios Tireóideos/deficiência
Membrana Nuclear
Proteínas/deficiência
Limites: Ratos
Animais
Responsável: BR1.1 - BIREME



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