163 resultados para real time polymerase chain reaction


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The aim of this study was to evaluate the relationship among oxidative DNA damage, density of Helicobacter pylori and the relevance of cagA, vacA and iceA genotypes of H. pylori. Gastric epithelial cells were isolated from 24 uninfected patients, 42 H. pylori infected patients with gastritis, and 61 patients with gastric cancer. Oxidative DNA damage was analyzed by the Comet assay, the density of H. pylori was measured by real-time polymerase chain reaction (PCR), and allelic variants of cagA, vacA and iceA were identified using the PCR. Infected patients by Helicobacter pylori cagA(+), vacAs1 m1 and iceA1 genotype showed higher levels of oxidative DNA damage than infected patients with H. pylori cagA(-), vacAs2 m2 and iceA2 genotypes and uninfected patients. Density of H. pylori did not influence oxidative DNA damage. Our results indicate that H. pylori genotype is more relevant than density for oxidative DNA damage.

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Objective To assess the viability of the early diagnosis of fetal gender in material plasma before 7 weeks of pregnancy by real-time polymerase chain reaction (real-time PCR), starting at 5 weeks of pregnancy.Method peripheral blood was collected from pregnant women, starting at 5 weeks of gestation. After centrifugation, plasma was separated for fetal DNA extraction. DNA was analyzed by quantitative real-time PCR for two genomic regions, one on the Y chromosome (DYS-14) and the other shared by both sexes (beta-globin), by the TaqMan Minor Groove Binder (MGB) probe assay. The results of the examinations were compared to fetal gender determined after delivery.Results A total of 79 examinations of fetal DNA in maternal plasma were performed for 52 pregnant women. Accuracy according to gestational age was 92.6% (25 of 27 cases) at 5 weeks, and 95.6% (22 of 23 cases) at 6 weeks. These results also demonstrate that fetal DNA is present at low concentrations in maternal plasma at 5 weeks (8.5 genome equivalents (GE)/mL) and 6 weeks (34.1 GE/mL) of pregnancy.Conclusion Quantitative real-time PCR and TaqMan MGB probes specific for the detection of fetal gender in maternal plasma starting at 5 weeks of gestation have good sensitivity and excellent specificity. Copyright (c) 2006 John Wiley & Sons, Ltd.

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Plant responses against pathogens cause up-and downward shifts in gene expression. To identify differentially expressed genes in a plant-virus interaction, susceptible tomato plants were inoculated with the potyvirus Pepper yellow mosaic virus (PepYMV) and a subtractive library was constructed from inoculated leaves at 72 h after inoculation. Several genes were identified as upregulated, including genes involved in plant defense responses (e. g., pathogenesis-related protein 5), regulation of the cell cycle (e. g., cytokinin-repressed proteins), signal transduction (e. g., CAX-interacting protein 4, SNF1 kinase), transcriptional regulators (e. g., WRKY and SCARECROW transcription factors), stress response proteins (e. g., Hsp90, DNA-J, 20S proteasome alpha subunit B, translationally controlled tumor protein), ubiquitins (e. g., polyubiquitin, ubiquitin activating enzyme 2), among others. Downregulated genes were also identified, which likewise display identity with genes involved in several metabolic pathways. Differential expression of selected genes was validated by macroarray analysis and quantitative real-time polymerase chain reaction. The possible roles played by some of these genes in the viral infection cycle are discussed.

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Purpose: to verify the viability of early diagnosis of fetal gender in maternal plasma by the real-time polymerase chain reaction (real-time PCR) starting at the 5th week of pregnancy. Methods: peripheral blood was collected from pregnant women with single fetus starting at the 5th week of gestation. After centrifugation, 0.4 mL plasma was separated for fetal DNA extraction. The DNA was analyzed in duplicate by real-time PCR for two genomic regions, one of the Y chromosome and the other common to both sexes, through the TaqMan® method, which uses a pair of primers and a fluorescent probe. Patients who aborted were excluded. Results: a total of 79 determinations of fetal DNA in maternal plasma were performed in 52 pregnant women. The results of the determinations were compared to fetal gender after delivery. Accuracy according to gestational age was 92.6% (25 of 27 cases) at 5 weeks with 87% sensitivity, and 95.6% (22 of 23 cases) at 6 weeks with 92% sensitivity. Starting at the 7th week of pregnancy, accuracy was 100% (29 of 29 cases). Specificity was 100% regardless of gestational age. Conclusion: real-time PCR for the detection of fetal gender in maternal plasma starting at the 5th week of gestation has good sensitivity and excellent specificity. There was agreement of the results in 100% of the cases in which male gender was diagnosed, regardless of gestational age, and from the 7th week of gestation for female gender diagnosis.

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Some recent articles have reported that mesenchymal stem cells (MSCs) can be induced to express hepatocyte markers by transplanting them into animal models of liver damage, or by in vitro culture with growth factors and cytokines. In this study, the aim is to evaluate the behavior of MSCs subjected to induction of hepatocyte differentiation. The MSCs were isolated from the bone marrow of 4 normal donors, characterized and subjected to both in vitro and in vivo induction of hepatocyte differentiation. The in vitro induced cells showed morphological changes, acquiring hepatocyte-like features. However, the immunophenotype of these cells was not modified. The induced cells exhibited no increase in albumin, cytokeratin 18 or cytokeratin 19 transcripts, when analyzed by real-time RT-PCR. The expression of albumin, cytokeratin 18 and alpha fetoprotein was also unchanged, according to immunofluorescence tests. In vivo, the MSC demonstrated a potential to migrate to damaged liver tissue in immunodeficient mice. Taken together, the results suggest that bone marrow MSCs are incapable of in vitro differentiation into hepatocytes by the approach used here, but are capable of homing to damaged hepatic tissue in vivo, suggesting a role for them in the repair of the liver. This contribution to tissue repair could be associated with a paracrine effect exerted by these cells.

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Astroglial cells are the most abundant cells in the mammalian central nervous system, yet our knowledge about their function in bovine Herpesvirus type 5 (BoHV-5) has been limited. The aim of this study was to detect by immunohistochemistry assay the reactive astrocytes for glial fibrilary acidic protein (GFAP) and vimentin (VIM), considered intermediate filaments of the cytoskeleton, localized in olfactory bulb from natural acute cases of BoHV-5 infection. All samples were submitted to virus isolation, real-time polymerase chain reaction (RT-PCR) and in situ hybridization (ISH) technique to confirm the virus transcription and respective genome. Samples were classified into four groups according to the severity of histological lesions. Groups III and IV, which histological lesions were classified as alacia, gliosis, satellitosis, neuronophagia and neuronal necrosis, 35% (± 1.8-2.1) of the inflammatory mononuclear cells, corresponded to CD3 positive lymphocytes. In the same group, 35% (± 1.8) of astrocytes were described as reactive to GFAP and VIM proteins. An agreement of r = 1.0 (P<0.0001) was found between histological lesions, intermediate filaments expression, viral DNA and transcription and CD3 lymphocytes. However, samples with mild histological lesions, 10.8 to 14.2% of astrocytes were classified as reactive to GFAP and VIM filaments. Our findings suggest that GFAP and VIM reactive astrocytes, in primary site of virus replication, seems to play an important role in neurovirulence, in spite of many questions concerning the virus immunopathology remains unclear.

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Melasma is a common acquired symmetrical hypermelanosis characterized by irregular light- to dark-brown macules on sun-exposed skin areas. The literature shows few studies on its physiopathogeny. However, changes in α-melanocyte stimulating hormone (α-MSH) secretion and melanocortin-1 receptor (MC1-R) expression may play a role to trigger this condition. Biopsies were taken from both melasma skin and adjacent perilesional normal skin of 44 patients. The biopsies were submitted for hematoxylin and eosin and Fontana-Masson staining and immunohistochemistry with Melan-A, α-MSH, and MC1-R, and processed for transmission electron microscopy. In some cases, they were submitted to MC1-R gene expression analysis by real-time polymerase chain reaction. Increased lymphohistiocytic infiltrate and solar elastosis, higher epidermal melanin were observed in melasma skin. Electron microscopy revealed a greater number of mature melanosomes in keratinocytes and melanocytes, and more prominent cytoplasmic organelles in melasma skin. There was no difference in melanocyte number between areas. However, melanocytes were larger and more dendritic in melasma skin. Immunohistochemistry with α-MSH and MC1-R showed significant labeling in melasmic epidermis but MC1-R messenger ribonucleic acid (RNAm) did not show significant quantitative difference between melasma and normal skin. © 2010 by Lippincott Williams & Wilkins.