945 resultados para Continuous-time Markov Chain


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To evaluate differential gene expression in penile tissue after treatment with the phosphodiesterase 5 (PDE5) inhibitor tadalafil, as of the three clinically available PDE5 inhibitors (sildenafil, tadalafil, and vardenafil) used for the treatment of erectile dysfunction (ED), tadalafil has a long half-life and low incidence of side-effects. In all, 32 adult rats were divided into two groups. The control group received 0.5 mL of drinking water alone, while the tadalafil group was treated with tadalafil at a dose of 0.27 mg/kg. At 4 h after treatment with water or tadalafil the rats were killed and the penile tissue was removed. The total RNA was isolated from the penile tissue from both groups and differentially expressed genes were identified by cDNA microarray analysis. To validate the expression data from the microarray analysis, quantitative real-time polymerase chain reaction (PCR) and immunohistochemistry were used. In all, 153 genes were differentially expressed between the control group and the tadalafil group. We validated the microarray results by quantitative PCR for the insulin-like growth factor binding protein 6 (IGFBP-6) gene and the neuronal calcium sensor 1 (NCS-1) gene, both of which were up-regulated in the tadalafil group, and for the natriuretic peptide receptor 1 (NPR-1) gene that was down-regulated in this group. Immunohistochemistry showed localization of the NCS-1 protein in sinusoid trabeculae of the corpus cavernosum in control and tadalafil-treated rats. There was differential expression in 153 genes after tadalafil treatment. Some of these genes such as IGFBP-6, NPR-1 and NCS-1, might result in new targets in the treatment of ED.

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Objective: We assessed the effect of enteral refeeding on the morphology, gene expression, and contraction of acute open wounds in previously malnourished rats using two different enteral diets. Methods: Adult male isogenic Lewis rats divided into two groups (eutrophic, n = 30; and previously malnourished, 12-15% body weight loss, n = 27) were subjected to cutaneous dorsal wounds and gastrostomy. Control rats received a standard oral diet (AIN-93M chow) plus enteral saline solution. Subject rats received chow plus a standard enteral diet or an enteral diet enriched with arginine and antioxidants. On post-trauma days 7 and 14, wound granulation tissue samples were collected for morphologic analysis using hematoxylin and eosin and picrosirius stain or immunohistochemistry slides and real-time polymerase chain reaction for collagen I and III gene expression. Wound contraction was also evaluated by comparing wound images from days 0,7, and 14. Results: Malnourished control rats had increased intensity and duration of wound inflammation, impaired increase of fibroblast cells contingent on post-trauma days 7 to 14, decreased expression of collagen III, and less wound contraction compared with eutrophic control rats. A specialized enteral diet did not improve wound healing of malnourished rats but did promote wound contraction at post-trauma day 7 in eutrophic rats. Conclusion: Short-term enteral refeeding, even with a specialized diet, failed to protect previously wounded malnourished rats from a prolonged inflammatory phase and impaired healing. (C) 2010 Elsevier Inc. All rights reserved.

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Hepatitis C virus (HCV) is a frequent cause of acute and chronic hepatitis and a leading cause for cirrhosis of the liver and hepatocellular carcinoma. HCV is classified in six major genotypes and more than 70 subtypes. In Colombian blood banks, serum samples were tested for anti-HCV antibodies using a third-generation ELISA. The aim of this study was to characterize the viral sequences in plasma of 184 volunteer blood donors who attended the ""Banco Nacional de Sangre de la Cruz Roja Colombiana,`` Bogota, Colombia. Three different HCV genomic regions were amplified by nested PCR. The first of these was a segment of 180 bp of the 5`UTR region to confirm the previous diagnosis by ELISA. From those that were positive to the 5`UTR region, two further segments were amplified for genotyping and subtyping by phylogenetic analysis: a segment of 380 bp from the NS5B region; and a segment of 391 bp from the E1 region. The distribution of HCV subtypes was: 1b (82.8%), 1a (5.7%), 2a (5.7%), 2b (2.8%), and 3a (2.8%). By applying Bayesian Markov chain Monte Carlo simulation, it was estimated that HCV-1b was introduced into Bogota around 1950. Also, this subtype spread at an exponential rate between about 1970 to about 1990, after which transmission of HCV was reduced by anti-HCV testing of this population. Among Colombian blood donors, HCV genotype 1b is the most frequent genotype, especially in large urban conglomerates such as Bogota, as is the case in other South American countries. J. Med. Virol. 82: 1889-1898, 2010. (C) 2010 Wiley-Liss, Inc.

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Molecular epidemiological data concerning the hepatitis B virus (HBV) in Chile are not known completely. Since the HBV genotype F is the most prevalent in the country, the goal of this study was to obtain full HBV genome sequences from patients infected chronically in order to determine their subgenotypes and the occurrence of resistance-associated mutations. Twenty-one serum samples from antiviral drug-naive patients with chronic hepatitis B were subjected to full-length PCR amplification, and both strands of the whole genomes were fully sequenced. Phylogenetic analyses were performed along with reference sequences available from GenBank (n = 290). The sequences were aligned using Clustal X and edited in the SE-AL software. Bayesian phylogenetic analyses were conducted by Markov Chain Monte Carlo simulations (MCMC) for 10 million generations in order to obtain the substitution tree using BEAST. The sequences were also analyzed for the presence of primary drug resistance mutations using CodonCode Aligner Software. The phylogenetic analyses indicated that all sequences were found to be the HBV subgenotype F1b, clustered into four different groups, suggesting that diverse lineages of this subgenotype may be circulating within this population of Chilean patients. J. Med. Virol. 83: 1530-1536, 2011. (C) 2011 Wiley-Liss, Inc.

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Background Collagen V shows promise as an inducer of interstitial lung fibrosis in experimental systemic sclerosis (SSc). Materials and methods Remodelling of the pulmonary interstitium was evaluated based on the clinical data and open lung biopsies from 15 patients with SSc. Normal lung tissues obtained from eight individuals who died of traumatic injuries were used as control group. Immunofluorescence, immunohistochemistry, morphometry, tri-dimensional reconstruction and a real-time polymerase chain reaction were used to evaluate the quantity, structure and molecular chains of collagen V. The impact of these markers was tested on clinical data. Results The main difference in collagen V content between SSc patients and the control group was an increased, abnormal and distorted fibre deposition in the alveolar septa and the pre-acinar artery wall. The lungs from SSc patients presented [alpha 1(V)] and [alpha 2(V)] mRNA chain expression increased, but [alpha 2(V)] was proportionally increased compared with the control group. High levels of collagen V were inversely associated with vital capacity (r = -0.72; P = 0.002), forced vital capacity (r = -0.76; P < 0.001), forced expiratory volume in 1-s (r = -0.89; P < 0.001) and diffusing capacity for carbon monoxide (r = -0.62; P = 0.04). Conclusions Abnormal collagen V fibres are overproduced in lungs from SSc patients and may play an important role in the pathogenesis of the disease as this molecule regulates tissue collagen assembly. The aberrant histoarchitecture observed in SSc can be related to the overexpression of the [alpha 2(V)] gene of unknown origin.

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Aims: Claudins, a large family of essential tight junction (TJ) proteins, are abnormally regulated in human carcinomas, especially claudin-7. The aim of this study was to investigate claudin-7 expression and alterations in oral squamous cell carcinoma (OSCC). Methods and results: Expression of claudin-7 was analysed in 132 cases of OSCC organized in a tissue microarray. Claudin-7 mRNA transcript was evaluated using real-time polymerase chain reaction and the methylation status of the promoter was also assessed. Claudin-7 was negative in 58.3% of the cases. Loss of claudin-7 protein expression was associated with recurrence (P = 0.019), tumour size (P = 0.014), clinical stage of OSCC (P = 0.055) and disease-free survival (P = 0.015). Down-regulation of the claudin-7 mRNA transcripts was observed in 78% of the cases, in accordance with immunoexpression. Analysis of the methylation status of the promoter region of claudin-7 revealed that treatment of O28 cells (that did not express claudin-7 mRNA transcripts) with 5-Aza-2`-Deoxycytidine (5-Aza-dC) led to the re-expression of claudin-7 mRNA transcript. Conclusion: Loss of claudin-7 expression is associated with important subcellular processes in OSCC with impact on clinical parameters.

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Objective: Prostate cancer (PCa) is the most frequent tumor in males in Brazil. Single nucleotide polymorphisms (SNP) have been demonstrated in the promoter region of matrix metalloproteinases (MMPs) genes and have been associated with development and progression of some cancers. In this study, our aim was to investigate a possible relation between polymorphism of the promoter region of the MMP2 gene and classical prognostic parameters in prostate cancer. Materials and methods: Genomic DNA was extracted using conventional protocols. The DNA sequence containing the polymorphic site was amplified by real-time polymerase chain reaction, using fluorescent probes (TaqMan). Results: In patients with tumors of a higher stage (pT3), a polymorphic allele in the MMP2 gene was more frequent (P = 0.026) than in patients with lower tumor stage. A polymorphic allele in the MMP2 gene was more frequent in Gleason >= 7 than in Gleason <= 6 (P = 0.042). Conclusions: We conclude that MMP2 polymorphism can be used together with pathological stage and Gleason score to identify patients with worse prognosis. Our results illustrate the potential use of MMP2 SNP as a molecular marker for prostate cancer. (C) 2010 Elsevier Inc. All rights reserved.

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Diesel exhaust is the major source of ultrafine particles released during traffic-related pollution. Subjects with chronic respiratory diseases are at greater risk for exacerbations during exposure to air pollution. This study evaluated the effects of subchronic exposure to a low-dose of diesel exhaust particles (DEP). Sixty male BALB/c mice were divided into two groups: (a) Saline: nasal instillation of saline (n = 30); and (b) DEP: nasal instillation of 30 mu g of DEP/10 mu l of saline (n = 30). Nasal instillations were performed 5 days a week, over 30 and 60 days. Animals were anesthetized with pentobarbital sodium (50 mg/kg intraperitoneal [i.p.]) and sacrificed by exsanguination. Bronchoalveolar lavage (BAL) fluid was performed to evaluate the inflammatory cell count and the concentrations of the interleukin (IL)-4, IL-10, and IL-13 by enzyme-linked immunosorbent assay (ELISA). The gene expression of oligomeric mucus/gel-forming (Muc5ac) was evaluated by real-time polymerase chain reaction (PCR). Histological analysis in the nasal septum and bronchioles was used to evaluate the bronchial and nasal epithelium thickness as well as the acidic and neutral nasal mucus content. The saline group (30 and 60 days) did not show any changes in any of the parameters. However, the instillation of DEP over 60 days increased the expression of Muc5ac in the lungs and the acid mucus content in the nose compared with the 30-day treatment, and it increased the total leukocytes in the BAL and the nasal epithelium thickness compared with saline for 60 days. Cytokines concentrations in the BAL were detectable, with no differences among the groups. Our data suggest that a low-dose of DEP over 60 days induces respiratory tract inflammation.

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Background: At least for a subset of patients, the clinical diagnosis of mild cognitive impairment (MCI) may represent an intermediate stage between normal aging and dementia. Nevertheless, the patterns of transition of cognitive states between normal cognitive aging and MCI to dementia are not well established. In this study we address the pattern of transitions between cognitive states in patients with MCI and healthy controls, prior to the conversion to dementia. Methods: 139 subjects (78% women, mean age, 68.5 +/- 6.1 years; mean educational level, 11.7 +/- 5.4 years) were consecutively assessed in a memory clinic with a standardized clinical and neuropsychological protocol, and classified as cognitively healthy (normal controls) or with MCI (including subtypes) at baseline. These subjects underwent annual reassessments (mean duration of follow-up: 2.7 +/- 1.1 years), in which cognitive state was ascertained independently of prior diagnoses. The pattern of transitions of the cognitive state was determined by Markov chain analysis. Results: The transitions from one cognitive state to another varied substantially between MCI subtypes. Single-domain MCI (amnestic and non-amnestic) more frequently returned to normal cognitive state upon follow-up (22.5% and 21%, respectively). Among subjects who progressed to Alzheimer`s disease (AD), the most common diagnosis immediately prior conversion was multiple-domain MCI (85%). Conclusion: The clinical diagnosis of MCI and its subtypes yields groups of patients with heterogeneous patterns of transitions between one given cognitive state to another. The presence of more severe and widespread cognitive deficits, as indicated by the group of multiple-domain amnestic MCI may be a better predictor of AD than single-domain amnestic or non-amnestic deficits. These higher-risk individuals could probably be the best candidates for the development of preventive strategies and early treatment for the disease.

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Background/Aims: Prolactin (PRL) secretion and its gene expression are inhibited by dopamine. Prolactinomas are the most common secreting pituitary adenomas, and dopamine agonists (DA) are the first choice for their treatment. However, a subset of patients is resistant to DA. As the mechanisms involved in DA resistance are not fully understood, the aim of this study was to obtain new insights regarding the molecular differences between the prolactinomas that are responsive to DA and those that are resistant. Methods: Tumor tissue samples were collected from 17 patients who harbored prolactinomas, which were classified as responsive or resistant according to their clinical and laboratorial reaction to DA. The expression of 6 genes was evaluated by real-time polymerase chain reaction: dopamine receptor type 2 (DRD 2), nerve growth factor-beta (NGFB) and its receptor (NGFR), estrogen receptor-alpha (ERA), estrogen receptor-beta (ERB) and the pituitary tumor transforming gene (PTTG). Results: Median DRD 2 and NGFR expression in responsive patients was significantly higher than in resistant ones (p = 0.029 and p = 0.020, respectively). Moreover, the expressions of DRD 2 and NGFR were positively correlated with PRL decrease during treatment (r = 0.66, p = 0.005 and r = 0.57, p = 0.044, respectively). Furthermore, ERB expression was positively correlated to PTTG expression (r = 0.68, p = 0.032) and negatively correlated to NGFB expression (r = -0.75, p = 0.02). Conclusions: DRD2 and NGFR expressions are related to the responsiveness of prolactinoma to DA. However, PTTG, ERB and ERA expressions are not. Also ERB, ERA and PTTG expressions did not present a clear correlation to tumor aggressiveness. Furthermore, the response of prolactinomas to DA should be viewed as a spectrum ranging from the most responsive to the most resistant ones. Copyright (c) 2008 S. Karger AG, Basel

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P>Background The evolution and therapeutic outcome of American tegumentary leishmaniasis (ATL) depend upon many factors, including the balance between Th1 and Th2 cytokines to control parasite multiplication and lesion extension. Other cytokines known for their role in inflammatory processes such as interleukin IL-17 or IL-18 as well as factors controlling keratinocyte differentiation and the inflammatory process in the skin, like the Notch system, could also be involved in the disease outcome. Notch receptors are a group of transmembrane proteins that regulate cell fate decisions during development and adulthood in many tissues, including keratinocyte differentiation and T-cell lineage commitment, depending on their activation by specific groups of ligands (Delta-like or Jagged). Objectives To compare the in situ expression of Notch system proteins (receptors, ligands and transcriptional factors) and cytokines possibly involved in the disease outcome (IL-17, IL-18, IL-23 and transforming growth factor-beta) in ATL cutaneous and mucosal lesions, according to the response to therapy with N-methyl glucamine. Methods Cutaneous and mucosal biopsies obtained from patients prior to therapy with N-methyl glucamine were analysed by immunohistochemistry and real-time polymerase chain reaction. Results Notch receptors and Delta-like ligands were found increased in patients with ATL, particularly those with poor response to therapy or with mucosal lesions. Conclusions The increase of Notch receptors and Delta-like ligands in patients with a poor response to treatment suggests that these patients would require a more aggressive therapeutic approach or at least a more thorough and rigorous follow-up.

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Background. Clinical manifestations of dengue vary in different areas of endemicity and between specific age groups, whereas predictors of outcome have remained controversial. In Brazil, the disease burden predominantly affects adults, with an increasing trend toward progression to dengue hemorrhagic fever (DHF) noted. Methods. A cohort of adults with confirmed cases of dengue was recruited in central Brazil in 2005. Patients were classified according to the severity of their disease. Associations of antibody responses, viremia levels (as determined by real-time polymerase chain reaction [PCR]), and serotypes (as determined by multiplex PCR) with disease severity were evaluated. Results. Of the 185 symptomatic patients > 14 years of age who had a confirmed case of dengue, 26.5% and 23.2% were classified as having intermediate dengue fever (DF)/ DHF (defined as internal hemorrhage, plasma leakage, manifested signs of shock, and/ or thrombocytopenia [platelet count, <= 50,000 platelets/mm(3)]) and DHF, respectively. The onset of intermediate DF/ DHF and DHF occurred at a late stage of disease, around the period of defervescence. Patients with DHF had abnormal liver enzyme levels, with a > 3-fold increase in aspartate aminotransferase level, compared with the range of values considered to be normal. Overall, 65% of patients presented with secondary infections with dengue virus, with such infection occurring in similar proportions of patients in each of the 3 disease category groups. Dengue virus serotype 3 (DV3) was the predominant serotype, and viremia was detected during and after defervescence among patients with DHF or intermediate DF/ DHF. Conclusions. Viremia was detected after defervescence in adult patients classified as having DHF or intermediate DF/ DHF. Secondary infection was not a predictor of severe clinical manifestation in adults with infected with the DV3 serotype.

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Background. The aims of this study were to define the mRNA expression profiles of MYCN, DDX1, TrkA, and TrkC in biopsy tumor samples from 64 Brazilian patients with neuroblastomas of different risk stages and to correlate altered expression with prognostic values. Procedure. Patients were retrospectively classified into low- (n = 11), intermediate- (n = 18), and high-risk (n = 35) groups using standard criteria. The mRNA levels of the above genes were measured by quantitative real-time polymerase chain reaction. Univariate analyses were performed and survival curves were plotted by the Kaplan-Meier method. Results. Of the 64 patients, 53% were female and 62.5% were older than 18 months. The 5-year overall survival (OS) for the entire cohort was 40.3%, with inferior median OS in patients identified in the intermediate- and high-risk groups. A significant difference in OS with respect to TrkA mRNA expression was found for the high-risk group vs. either the low- or intermediate-risk groups (P < 0.01, log rank test). Within the intermediate-risk group, neuroblastoma patients with positive TrkA mRNA expression had better clinical outcomes than patients with no TrkA transcript expression (P = 0.004). Another difference in OS was only found between the intermediate- and high-risk groups (P < 0.027, log rank test). No significant correlation of mRNA expression and survival outcome could be detected for the MYCN, DDX1. Conclusions. Positive expression of TrkA mRNA may be a clinically useful addition to the current risk classification system, allowing the identification of NB tumors with favorable prognosis. Pediatr Blood Cancer 2011; 56: 749-756. (c) 2010 Wiley-Liss, Inc.

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Background: Human postnatal stem cells have been identified in periodontal ligaments (PDLs). In this study, the in vitro biologic properties of CD105(+) enriched cell subsets from PDLs harvested from deciduous (DePDL) and permanent (PePDL) teeth are comparatively assessed. Methods: PDL tissue was obtained from 12 teeth (six primary and six permanent) from which CD105(+) CD34(-) CD45(-) cells were isolated by magnetic cell sorting. To identify and quantitatively compare the stem cell markers, DePDL and PePDL cells were assessed for CD166 surface antigen expression by flow cytometry, real-time polymerase chain reaction, and immunostaining for Stro-1 and Oct-4, osteogenic and adipogenic differentiation, and proliferation rate by trypan blue method. Results: Magnetic cell sorting isolated cell populations containing 23.87% (+/- 11.98%) and 11.68% (+/- 6.27%) of CD105(+) expressing cells from PePDL and DePDL, respectively. Flow cytometric analysis demonstrated a higher proportion of CD105(+) cells coexpressing CD166 surface antigen in PePDL, whereas immunostaining and real-time polymerase chain reaction analysis demonstrated that both cell subsets expressed Stro-1 and Oct-4. DePDL-CD105(+) subsets were more proliferative compared to PePDL subsets, and both cell populations showed multipotential capabilities to differentiate in vitro to osteoblast/cementoblast- and adipocyte-like cells. However, a higher expression of adipogenic-related genes was observed in DePDL cells, whereas PePDL-CD105(+) cell subset presented a more homogeneous osteoblast/cementoblast response. Conclusion: These findings demonstrate that highly purified mesenchymal progenitor cell subsets can be obtained from the PDLs of both deciduous and permanent teeth, and further indicate phenotype dissimilarities that may have an impact on their clinical applications. J Periodontol 2010;81:1207-1215.

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Objective. The relationship of multipotent mesenchymal stromal cells (MSC) with pericytes and fibroblasts has not been established thus far, although they share many markers of primitive marrow stromal cells and the osteogenic, adipogenic, and chondrogenic differentiation potentials. Materials and Methods. We compared MSCs from adult or fetal tissues, MSC differentiated in vitro, fibroblasts and cultures of retinal pericytes obtained either by separation with anti-CD146 or adhesion. The characterizations included morphological, immunophenotypic, gene-expression profile, and differentiation potential. Results. Osteogenic, adipocytic, and chondrocytic differentiation was demonstrated for MSC, retinal perivascular cells, and fibroblasts. Cell morphology and the phenotypes defined by 22 markers were very similar. Analysis of the global gene expression obtained by serial analysis of gene expression for 17 libraries and by reverse transcription polymerase chain reaction of 39 selected genes from 31 different cell cultures, revealed similarities among MSC, retinal perivascular cells, and hepatic stellate cells. Despite this overall similarity, there was a heterogeneous expression of genes related to angiogenesis, in MSC derived from veins, artery, perivascular cells, and fibroblasts. Evaluation of typical pericyte and MSC transcripts, such as NG2, CD146, CD271, and CD140B on CD146 selected perivascular cells and MSC by real-time polymerase chain reaction confirm the relationship between these two cell types. Furthermore, the inverse correlation between fibroblast-specific protein-1 and CD146 transcripts observed on pericytes, MSC, and fibroblasts highlight their potential use as markers of this differentiation pathway. Conclusion. Our results indicate that human MSC and pericytes are similar cells located in the wall of the vasculature, where they function as cell sources for repair and tissue maintenance, whereas fibroblasts are more differentiated cells with more restricted differentiation potential. (C) 2008 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc.