961 resultados para CHROMATIN IMMUNOPRECIPITATION


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Foram estudados tumores de mama em cadelas, comparando o seu padrão citológico, obtido através da Citologia Aspirativa por Agulha Fina (CAAF), com os resultados da histopatologia. Num período de um ano, as cadelas trazidas ao Hospital Veterinário -- UNESP -- Câmpus de Jaboticabal foram submetidas a exérese cirúrgica dos tumores mamários. As amostras foram avaliadas de acordo com parâmetros estruturais utilizados nos tumores mamários humanos, como grau de atipia, critérios nucleares, padrão de cromatina e nucléolos, alta celularidade e pouca coesão intercelular. Utilizaram-se estes critérios para diferenciar tumores mamários benignos de malignos com 63% de diagnósticos concordantes, sensibilidade de 73% e especificidade de 83%. Nossos dados mostraram ter uma correlação positiva com o prognóstico, demonstrando que é possível reconhecer variáveis estruturais de malignidade na citopatologia para obter um diagnóstico precoce e um prognóstico seguro.

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The objectives of this study were to assess the effects of induced testicular degeneration in Bos taurus indicus (Nellore) bulls on changes in seminal characteristics and fertilizing ability of sperm. Four Nellore bulls (30-36-month-old, 500-550 kg) with good seminal quality (> 80% motile and morphologically normal sperm) had serotal insulation applied for 5 d. Semen was collected by electroejaculation and cryopreserved at a the pre-insulation moment, and 7, 14, and 21 d after insulation was removed. Gross motility, vigor of sperm movement (1-5), acrosome integrity, sperm morphology (phase-contrast microscopy), nuclear vacuoles and abnormal chromatin (Feulgen-stain) were determined after sperm preparations for in vitro fertilization (IVF). Prior to IVF, sperm were separated using a Percoll gradient (45% and 90%). Normal sperm decreased (P < 0.05) 14 and 21 d after insulation was removed. on 14 and 21 d, the incidence of head defects (9.7 +/- 0.6 and 17.0 +/- 0.8, respectively; mean +/- S.E.M) was higher (P < 0.05) in agreement with the incidence of nuclear vauoles (14.0 +/- 5.0 and 12.3 +/- 2.3) and abnormal chromatin (24.4 +/- 7.2 and 30.8 +/- 2.8). Although the frequency of cleaved oocytes decreased only on 21 d (P < 0.05), blastocyst rates were lower (P < 0.05) than pre-insulation on 14 and 21 d. In regression analyses, only nuclear vacuoles, head defects and intact acrosome accounted for differences in cleavage (R(2) = 0.38, 0.48, and 0.30, respectively) and blastocyst rates (R(2) = 0.35, 0.37, and 0.44). Abnormal chromatin was associated only with blastocyst rates (R(2) = 0.35). In conclusion, blastocyst rate was more sensitive than cleavage rate and the assessment of nuclear integrity is recommended to predict the fertilizing ability of bull sperm. (c) 2008 Elsevier B.V. All rights reserved.

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We investigated the possibility that Chagas' patients develop an autoimmune response to human UsnRNPs or Sm epitopes. Using purified human UsnRNPs we detected anti-human UsnRNPs antibodies in sera from patients with Chagas' disease. The antibodies were also detected using peptide-ELISA containing the Sm-motif 1 domain, showing that 61% (31/51) of the Chagas sera contained antibodies against the Sm-motif 1. Our preliminary results obtained by immunoprecipitation using Chagas chronically infected Balb/C sera and HeLa nuclear extracts showed that some autoantibodies could also be found during the course of the disease. Groups of 20 mice tone-month-old) were infected i.p. with Y strain 30 bloodstream trypomastigotes and killed at 60 days post-infection and sera were used for immunoprecipitation analysis as mentioned, These antibodies cross-reacted with U2 snRNP in HeLa nuclear extract and revealed many different bands in T. cruzi nuclear extract. These results suggest that the autoantibodies may have a role in the pathogenesis of the disease,

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We detected anti-human small nuclear ribonucleoprotein (snRNP) autoantibodies in chagasic patients by different immunological methods using HeLa snRNPs. ELISA with Trypanosoma cruzi total lysate antigen or HeLa human U small nuclear ribonucleoproteins (UsnRNPs) followed by incubation with sera from chronic chagasic and non-chagasic cardiac patients was used to screen and compare serum reactivity. Western blot analysis using a T. cruzi total cell extract was also performed in order to select some sera for Western blot and immunoprecipitation assays with HeLa nuclear extract. ELISA showed that 73 and 95% of chronic chagasic sera reacted with HeLa UsnRNPs and T. cruzi antigens, respectively. The Western blot assay demonstrated that non-chagasic cardiac sera reacted with high molecular weight proteins present in T. cruzi total extract, probably explaining the 31% reactivity found by ELISA. However, these sera reacted weakly with HeLa UsnRNPs, in contrast to the chagasic sera, which showed autoantibodies with human Sm (from Stefanie Smith, the first patient in whom this activity was identified) proteins (B/B', D1, D2, D3, E, F, and G UsnRNP). Immunoprecipitation reactions using HeLa nuclear extracts confirmed the reactivity of chagasic sera and human UsnRNA/RNPs, while the other sera reacted weakly only with U1snRNP. These findings agree with previously reported data, thus supporting the idea of the presence of autoimmune antibodies in chagasic patients. Interestingly, non-chagasic cardiac sera also showed reactivity with T. cruzi antigen and HeLa UsnRNPs, which suggests that individuals with heart disease of unknown etiology may develop autoimmune antibodies at any time. The detection of UsnRNP autoantibodies in chagasic patients might contribute to our understanding of how they develop upon initial T. cruzi infection.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The present study aimed to evaluate the correlation between the motile sperm organelle morphology examination (MSOME) and a well-known sperm morphology classification (Tygerberg criteria). For MSOME, spermatozoa were analysed at x8400 magnification by inverted microscope equipped with Nomarski differential interference contrast optics, Uplan Apo x 100 oil/1.35 objective lens and variable zoom lens. By Tygerberg criteria, the semen underwent morphological evaluation as described in the literature. Regression analysis demonstrated significant positive correlation between percentage of normal sperm forms by Tygerberg criteria and by MSOME (r = 0.83, P < 0.0001). However, the incidence of normal spermatozoa by Tygerberg criteria (9.4%) was significantly higher (P < 0.0001) than under MSOME (3.3%). Despite the highly positive correlation, MSOME is a much stricter criterion of sperm morphology classification, since it identifies vacuoles and chromatin abnormalities that are not evaluated with the same precision by the analysis of Tygerberg criteria. MSOME should be included among the routine criteria for semen analysis. In addition, MSOME should be used for selection of spermatozoa for intracytoplasmic sperm injection based on the already published literature, as this is a good selection tool.

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The aim of this study was to determine the extent of DNA fragmentation and the presence of denatured single-stranded or normal double-stranded DNA in spermatozoa with large nuclear vacuoles (LNV) selected by high magnification. Fresh semen samples from 30 patients were prepared by discontinuous isolate concentration gradient. Spermatozoa with normal nucleus (NN) and LNV were selected at x8400 magnification and placed on different slides. DNA fragmentation was determined by TUNEL assay. Denatured and double-stranded DNA was identified by the acridine orange fluorescence method. DNA fragmentation in spermatozoa with LNV (29.1%) was significantly higher (P < 0.001) than in spermatozoa with NN (15.9%). Therefore, cleavage of genomic DNA in low molecular weight DNA fragments (mono- and oligonucleosomes), and single-strand breaks (nicks) in high molecular weight DNA occur more frequently in spermatozoa with LNV. Similarly, the percentage of denatured-stranded DNA in spermatozoa with LNV (67.9%) was significantly higher (P < 0.0001) than in spermatozoa with NN (33.1%). The high level of denatured DNA in spermatozoa with LNV suggests precocious decondensation and disaggregation of sperm chromatin fibres. The results show an association between LNV and DNA damage in spermatozoa, and support the routine morphological selection and injection of motile spermatozoa at high magnification for ICSI.

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OBJECTIVE To (1) analyze possible relationships between motile sperm organelle morphology examination (MSOME) and sperm chromatin status, aneuploidy incidence, and patient's age; (2) determine the effects of sperm morphologic abnormalities on intracytoplasmic sperm injection (ICSI) outcomes; and (3) identify the benefits of intracytoplasmic morphologically selected sperm injection (IMSI) in patients with high DNA fragmentation rate.METHODS The study was performed in 50 patients undergoing ICSI cycles. The MSOME, sperm DNA fragmentation, and sperm aneuploidy incidence were performed in 200 sperm cells of each patient. Regression models were used to assess the relationships among sperm morphology and sperm aneuploidy, sperm DNA fragmentation, patient's age, and ICSI outcomes. In cycles with patients showing a high incidence of DNA fragmentation, oocytes were split into 2 groups according to the sperm selection method: Standard-ICSI (n = 82) and IMSI (n = 79). Fertilization and high-quality embryo rates were compared between the groups.RESULTS A close relationship between sperm DNA fragmentation and the presence of vacuoles in the MSOME was noted. The patient's age was correlated to the presence of vacuoles. No correlation between sperm aneuploidy and IMSI was observed. Vacuolated cells were negatively correlated with fertilization, pregnancy, and implantation. In patients with a high incidence of sperm DNA fragmentation, fertilization and high-quality embryo rates were similar when comparing IMSI and Standard-ICSI.CONCLUSIONS Our data demonstrate a correlation between paternal age and the incidence of nuclear vacuoles, as well as an effect of large and small vacuoles on late embryo development. UROLOGY 78: 786-791, 2011. (C) 2011 Elsevier B.V.

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Background: The present study aimed to evaluate the efficacy of the hyaluronic acid (HA) binding assay in the selection of motile spermatozoa with normal morphology at high magnification (8400x).Methods: A total of 16592 prepared spermatozoa were selected and classified into two groups: Group I, spermatozoa which presented their head attached to an HA substance (HA-bound sperm), and Group II, those spermatozoa that did not attach to the HA substance (HA-unbound sperm). HA-bound and HA-unbound spermatozoa were evaluated according to the following sperm forms: 1-Normal morphology: normal nucleus (smooth, symmetric and oval configuration, length: 4.75+/-2.8 mu m and width: 3.28+/-0.20 mu m, no extrusion or invagination and no vacuoles occupied more than 4% of the nuclear area) as well as acrosome, post-acrosomal lamina, neck, tail, besides not presenting a cytoplasmic droplet or cytoplasm around the head; 2-Abnormalities of nuclear form (a-Large/small; b-Wide/narrow; c-Regional disorder); 3-Abnormalities of nuclear chromatin content (a-Vacuoles: occupy >4% to 50% of the nuclear area and b-Large vacuoles: occupy >50% of the nuclear area) using a high magnification (8400x) microscopy system.Results: No significant differences were obtained with respect to sperm morphological forms and the groups HA-bound and HA-unbound. 1-Normal morphology: HA-bound 2.7% and HA-unbound 2.5% (P = 0.56). 2-Abnormalities of nuclear form: a-Large/small: HA-bound 1.6% vs. HA-unbound 1.6% (P = 0.63); b-Wide/narrow: HA-bound 3.1% vs. HA-unbound 2.7% (P = 0.13); c-Regional disorders: HA-bound 4.7% vs. HA-unbound 4.4% (P = 0.34). 3. Abnormalities of nuclear chromatin content: a-Vacuoles >4% to 50%: HA-bound 72.2% vs. HA-unbound 72.5% (P = 0.74); b-Large vacuoles: HA-bound 15.7% vs. HA-unbound 16.3% (P = 0.36).Conclusions: The findings suggest that HA binding assay has limited efficacy in selecting motile spermatozoa with normal morphology at high magnification.

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Loss of allele-specific expression by the imprinted genes IGF2 and H19 has been correlated with a differentially methylated region (DMR) upstream to the H19 gene. The H19-DMR contains seven potential CCCTC-binding factor (CTCF) binding sites. CTCF is a chromatin insulator and a multifunctional transcription factor whose binding to the H19-DMR is suppressed by DNA methylation. Our study included a group of 41 head and neck squamous cell carcinoma (HNSCC) samples. The imprinting status of the H19 gene was analyzed in 11 out of 35 positive cases for H19 gene expression, and only 1 of them showed loss of imprinting. We detected a significant correlation (P=0.041, Fisher's exact test) between H19 expression and tumor recurrence. Among H19 positive cases, six were T2, in which five developed recurrence and/or metastasis. Inversely, in the group of tumors that showed no H19 gene expression, 5 out of 24 were T2 and only I presented regional recurrence. These data support the hypothesis that H19 expression could be used as a prognostic marker to indicate recurrence in early stage tumors. We also examined the methylation of the CTCF binding site 1 in a subgroup of these samples. The H19 gene silencing and loss of imprinting were not correlated with the methylation pattern of the CTCF binding site 1. However, the significant correlation between H19 expression and tumor recurrence suggest that this transcript could be a marker for the progression of HNSCC. (c) 2005 Wiley-Liss, Inc.