RESUMEN
BACKGROUND: The present study investigates whether epigenetic differences emerge in the heart of patients undergoing cardiac surgery for an aortic valvular replacement (AVR) or coronary artery bypass graft (CABG). An algorithm is also established to determine how the pathophysiological condition might influence the human biological cardiac age. RESULTS: Blood samples and cardiac auricles were collected from patients who underwent cardiac procedures: 94 AVR and 289 CABG. The CpGs from three independent blood-derived biological clocks were selected to design a new blood- and the first cardiac-specific clocks. Specifically, 31 CpGs from six age-related genes, ELOVL2, EDARADD, ITGA2B, ASPA, PDE4C, and FHL2, were used to construct the tissue-tailored clocks. The best-fitting variables were combined to define new cardiac- and blood-tailored clocks validated through neural network analysis and elastic regression. In addition, telomere length (TL) was measured by qPCR. These new methods revealed a similarity between chronological and biological age in the blood and heart; the average TL was significantly higher in the heart than in the blood. In addition, the cardiac clock discriminated well between AVR and CABG and was sensitive to cardiovascular risk factors such as obesity and smoking. Moreover, the cardiac-specific clock identified an AVR patient's subgroup whose accelerated bioage correlated with the altered ventricular parameters, including left ventricular diastolic and systolic volume. CONCLUSION: This study reports on applying a method to evaluate the cardiac biological age revealing epigenetic features that separate subgroups of AVR and CABG.
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Metilación de ADN , Implantación de Prótesis de Válvulas Cardíacas , Humanos , Implantación de Prótesis de Válvulas Cardíacas/efectos adversos , Implantación de Prótesis de Válvulas Cardíacas/métodos , Resultado del Tratamiento , Válvula Aórtica/cirugía , Epigénesis GenéticaRESUMEN
PURPOSE: In presence of indeterminate lesions by fine needle aspiration (FNA), thyroid cancer cannot always be easily diagnosed by conventional cytology. As a consequence, unnecessary removal of thyroid gland is performed in patients without cancer based on the lack of optimized diagnostic criteria. Aim of this study is identifying a molecular profile based on long noncoding RNAs (lncRNAs) expression capable to discriminate between benign and malignant nodules. METHODS: Patients were subjected to surgery (n = 19) for cytologic suspicious thyroid nodules or to FNA biopsy (n = 135) for thyroid nodules suspicious at ultrasound. Three thyroid-specific genes (TG, TPO, and NIS), six cancer-associated lncRNAs (MALAT1, NEAT1, HOTAIR, H19, PVT1, MEG3), and two housekeeping genes (GAPDH and P0) were analyzed using Droplet Digital PCR (ddPCR). RESULTS: Based on higher co-expression in malignant (n = 11) but not in benign (n = 8) nodules after surgery, MALAT1, PVT1 and HOTAIR were selected as putative cancer biomarkers to analyze 135 FNA samples. Cytological and histopathological data from a subset of FNA patients (n = 34) were used to define a predictive algorithm based on a Naïve Bayes classifier using co-expression of MALAT1, PVT1, HOTAIR, and cytological class. This classifier exhibited a significant separation capability between malignant and benign nodules (P < 0.0001) as well as both rule in and rule out test potential with an accuracy of 94.12% and a negative predictive value (NPV) of 100% and a positive predictive value (PPV) of 91.67%. CONCLUSIONS: ddPCR analysis of selected lncRNAs in FNA biopsies appears a suitable molecular tool with the potential of improving diagnostic accuracy.
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ARN Largo no Codificante , Neoplasias de la Tiroides , Nódulo Tiroideo , Teorema de Bayes , Biopsia con Aguja Fina , Detección Precoz del Cáncer , Humanos , ARN Largo no Codificante/genética , Sensibilidad y Especificidad , Neoplasias de la Tiroides/diagnóstico , Neoplasias de la Tiroides/genética , Nódulo Tiroideo/diagnóstico , Nódulo Tiroideo/genéticaRESUMEN
Although a significant subset of prostate tumors remain indolent during the entire life, the advanced forms are still one of the leading cause of cancer-related death. There are not reliable markers distinguishing indolent from aggressive forms. Here we highlighted a new molecular circuitry involving microRNA and coding genes promoting cancer progression and castration resistance. Our preclinical and clinical data demonstrated that c-Met activation increases miR-130b levels, inhibits androgen receptor expression, promotes cancer spreading and resistance to hormone ablation therapy. The relevance of these findings was confirmed on patients' samples and by in silico analysis on an independent patient cohort from Taylor's platform. Data suggest c-Met/miR-130b axis as a new prognostic marker for patients' risk assessment and as an indicator of therapy resistance. Our results propose new biomarkers for therapy decision-making in all phases of the pathology. Data may help identify high-risk patients to be treated with adjuvant therapy together with alternative cure for castration-resistant forms while facilitating the identification of possible patients candidates for anti-Met therapy. In addition, we demonstrated that it is possible to evaluate Met/miR-130b axis expression in exosomes isolated from peripheral blood of surgery candidates and advanced patients offering a new non-invasive tool for active surveillance and therapy monitoring.
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Biomarcadores de Tumor/genética , MicroARNs/genética , Neoplasias de la Próstata Resistentes a la Castración/genética , Neoplasias de la Próstata/genética , Proteínas Proto-Oncogénicas c-met/genética , Animales , Biomarcadores de Tumor/metabolismo , Línea Celular Tumoral , Progresión de la Enfermedad , Xenoinjertos , Humanos , Masculino , Ratones , Ratones Endogámicos NOD , MicroARNs/metabolismo , Neoplasias de la Próstata/enzimología , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata Resistentes a la Castración/enzimología , Neoplasias de la Próstata Resistentes a la Castración/metabolismo , Proteínas Proto-Oncogénicas c-met/metabolismoRESUMEN
BACKGROUND: In the European scenario Municipal Waste Management (MWM) is very heterogeneous, and many countries did not achieve yet the decoupling between economic growth and MW production. The objectives of the study were to evaluate temporal trends of MWM and economic indicators to evidence differences between Germany and Italy, and to assess the relationship between economic indicators and MW production, to highlight whenever decoupling was achieved. METHODS: Time series analyses (1995-2010) of data related to MWM and income/consumption indicators were performed, and simple regression analyses were run to evaluate the relationship between economic drivers and MW production. RESULTS: Income/consumption indicators show a constant increment in both countries, while different trends appear for MWM. German MW production was reduced, and, over the years, the main disposal method rose from landfill towards recycling. On the contrary, Italian MW production increased, and landfilling has been always the most common method for disposal waste. Besides, the percentage of MW collected separately and packaging recovered was higher in Germany than in Italy for all the investigated period. Moreover, Germany appears to have decoupled MW production from economic growth, while Italian MW production is significant positively associated to it. CONCLUSIONS: Germany emerges as a virtuous country, while Italy appears as the "example not to follow". Differences could be determined by the contribution of several factors, such as educational levels, urbanization, population characteristics, employment/unemployment rates, expenditure in research and health issues, that should be studied indeed.
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Administración de Residuos/normas , Alemania , ItaliaRESUMEN
We recently identified in prostate tumors (PCa) a transcriptional prognostic signature comprising a significant number of genes differentially regulated in patients with worse clinical outcome. Induction of up-regulated genes was due to chromatin remodeling by a combinatorial complex between estrogen receptor (ER)-ß and endothelial nitric oxide synthase (eNOS). Here we show that this complex can also repress transcription of prognostic genes that are down-regulated in PCa, such as the glutathione transferase gene GSTP1. Silencing of GSTP1 is a common early event in prostate carcinogenesis, frequently caused by promoter hypermethylation. We validated loss of glutathione transferase (GST) P1-1 expression in vivo, in tissue microarrays from a retrospective cohort of patients, and correlated it with decreased disease-specific survival. Furthermore, we show that in PCa cultured cells ERß/eNOS causes GSTP1 repression by being recruited at estrogen responsive elements in the gene promoter with consequential remodeling of local chromatin. Treatment with ERß antagonist or its natural ligand 5α-androstane-3ß,17ß-diol, eNOS inhibitors or ERß small interference RNA abrogated the binding and reversed GSTP1 silencing, demonstrating the direct involvement of the complex. In vitro, GSTP1 silencing by ERß/eNOS was specific for cells from patients with worse clinical outcome where it appeared the sole mechanism regulating GSTP1 expression because no promoter hypermethylation was present. However, in vivo chromatin immunoprecipitation assays on fresh PCa tissues demonstrated that silencing by ERß/eNOS can coexist with promoter hypermethylation. Our findings reveal that the ERß/eNOS complex can exert transcriptional repression and suggest that this may represent an epigenetic event favoring inactivation of the GSTP1 locus by methylation. Moreover, abrogation of ERß/eNOS function by 3ß-adiol emphasizes the significance of circulating or locally produced sex steroid hormones or their metabolites in PCa biology with relevant clinical/therapeutic implications.
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Receptor beta de Estrógeno/metabolismo , Silenciador del Gen , Gutatión-S-Transferasa pi/genética , Óxido Nítrico Sintasa de Tipo III/metabolismo , Neoplasias de la Próstata/genética , Androstano-3,17-diol/farmacología , Androstano-3,17-diol/fisiología , Línea Celular Tumoral , Movimiento Celular , Ensamble y Desensamble de Cromatina , Metilación de ADN , Estradiol/farmacología , Estradiol/fisiología , Receptor beta de Estrógeno/agonistas , Gutatión-S-Transferasa pi/metabolismo , Humanos , Masculino , Pronóstico , Regiones Promotoras Genéticas , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/metabolismo , Transporte de Proteínas , Análisis de Matrices Tisulares , Transcripción Genética/efectos de los fármacosAsunto(s)
Envejecimiento/sangre , Inmunoglobulina D/sangre , Adolescente , Niño , Preescolar , Estudios Transversales , Humanos , Lactante , Recién Nacido , ItaliaRESUMEN
Several studies show that inflammatory components may contribute to atherosclerosis and increase the risk for myocardial infarction (MI). Interleukin-6 (IL-6) is a key pro-inflammatory and immune-modulatory cytokine of relevance for cardiovascular diseases. In this case-control study, 200 patients with MI and 257 healthy controls were genotyped for the polymorphism present in -174 promoter region of the IL-6 gene. Plasma concentrations of IL-6 and C-reactive protein (CRP) in a group of patients and controls were measured. The -174 C allele was associated with an increased risk of developing MI (OR = 2.886, c.i. = 1.801-4.624, P = 0.0001) in older patients, while no association was found in younger ones. The IL-6 plasma levels were higher in patients with MI carrying the CC genotype than in GG patients (CC carriers, IL-6 = 2.97 pg mL(-1) vs. GG carriers = 1.81 pg mL(-1), P = 0.016). A positive correlation of IL-6 levels with those of CRP in serum from patients with MI was also found. Data from this study suggest that the C allele of the promoter polymorphism in the IL-6 gene is a risk factor for MI in the elderly, and the production of the IL-6 is differentially affected by different genotypes of the IL-6 -174 promoter polymorphism.
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Predisposición Genética a la Enfermedad , Interleucina-6/genética , Infarto del Miocardio/genética , Polimorfismo de Nucleótido Simple , Regiones Promotoras Genéticas/genética , Factores de Edad , Anciano , Alelos , Proteína C-Reactiva/análisis , Proteína C-Reactiva/genética , Estudios de Casos y Controles , Genotipo , Humanos , Interleucina-6/sangre , Masculino , Persona de Mediana Edad , Infarto del Miocardio/sangre , Factores de RiesgoRESUMEN
Human coagulation factor XII promoter contains an estrogen response element that mediates ligand-activated ERalpha induction of coagulation factor XII gene expression. The 3'-half of coagulation factor XII-estrogen response element overlaps a putative CCAAT box, the widespread regulatory element specifically recognized by the heteromeric transcription factor NF-Y. Transient cotransfection of NF-Y and ERalpha results in strong inhibition of estrogen stimulation of coagulation factor XII promoter activity. NF-Y antagonism is primarily exerted by the NF-YA subunit and does not require binding to the CCAAT element, as NF-YA mutants with impaired DNA binding capacity retain the ability to inhibit ERalpha trans-activation. EMSAs with increasing concentrations of recombinant NF-Y do not detect the formation of NF-Y-DNA complexes or show impairment of ERalpha binding to estrogen response element. Immunoprecipitation of whole cell extracts with anti-ERalpha antibody reveals an in vivo association between the two transcription factors, which is abolished by deletion of the NF-YA carboxyl-terminus. In functional experiments with sequential NF-YA deletion mutants the HAP2-homology region appears essential in eliciting NF-YA antagonistic activity. In conclusion, our results demonstrate that heteromeric transcription factor NF-Y inhibits estrogen induction of coagulation factor XII promoter in a DNA binding-independent fashion and suggest a novel role for NF-Y as a partner for the ERalpha transcription complex.
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Factor de Unión a CCAAT/fisiología , Factor XII/genética , Receptores de Estrógenos/fisiología , Activación Transcripcional/fisiología , Células 3T3 , Animales , Secuencia de Bases/genética , Factor de Unión a CCAAT/genética , Factor de Unión a CCAAT/farmacología , ADN/metabolismo , Estradiol/farmacología , Receptor alfa de Estrógeno , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Ratones , Datos de Secuencia Molecular , Regiones Promotoras Genéticas/efectos de los fármacos , Isoformas de Proteínas/genética , Isoformas de Proteínas/farmacología , Estructura Terciaria de Proteína/genética , Transcripción Genética/efectos de los fármacos , Células Tumorales CultivadasAsunto(s)
Anticoagulantes/uso terapéutico , Cardiopatías/prevención & control , Heparina de Bajo-Peso-Molecular/uso terapéutico , Enfermedad Aguda , Angina Inestable/tratamiento farmacológico , Angina Inestable/prevención & control , Anticoagulantes/administración & dosificación , Fibrilación Atrial/tratamiento farmacológico , Cardiopatías/tratamiento farmacológico , Heparina de Bajo-Peso-Molecular/administración & dosificación , Infarto del Miocardio/tratamiento farmacológico , Infarto del Miocardio/prevención & controlRESUMEN
In mammals, molecular mechanisms and factors involved in the tight regulation of telomerase expression and activity are still largely undefined. In this study, we provide evidence for a role of estrogens and their receptors in the transcriptional regulation of hTERT, the catalytic subunit of human telomerase and, consequently, in the activation of the enzyme. Through a computer analysis of the hTERT 5'-flanking sequences, we identified a putative estrogen response element (ERE) which was capable of binding in vitro human estrogen receptor alpha (ERalpha). In vivo DNA footprinting revealed specific modifications of the ERE region in ERalpha-positive but not ERalpha-negative cells upon treatment with 17beta-estradiol (E2), indicative of estrogen-dependent chromatin remodelling. In the presence of E2, transient expression of ERalpha but not ERbeta remarkably increased hTERT promoter activity, and mutation of the ERE significantly reduced this effect. No telomerase activity was detected in human ovary epithelial cells grown in the absence of E2, but the addition of the hormone induced the enzyme within 3 h of treatment. The expression of hTERT mRNA and protein was induced in parallel with enzymatic activity. This prompt estrogen modulation of telomerase activity substantiates estrogen-dependent transcriptional regulation of the hTERT gene. The identification of hTERT as a target of estrogens represents a novel finding which advances the understanding of telomerase regulation in hormone-dependent cells and has implications for a potential role of hormones in their senescence and malignant conversion.
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Estradiol/metabolismo , Regulación Enzimológica de la Expresión Génica , ARN , Telomerasa/genética , Transcripción Genética , Células 3T3 , Animales , Secuencia de Bases , Dominio Catalítico , Línea Celular , ADN Complementario , Proteínas de Unión al ADN , Células Epiteliales/citología , Estradiol/farmacología , Receptor alfa de Estrógeno , Receptor beta de Estrógeno , Femenino , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Células HeLa , Humanos , Ligandos , Ratones , Datos de Secuencia Molecular , Ovario/citología , Regiones Promotoras Genéticas , Receptores de Estrógenos/genética , Receptores de Estrógenos/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Telomerasa/metabolismo , Transcripción Genética/efectos de los fármacosRESUMEN
Recovery of p53 function in undifferentiated thyroid carcinoma cells carrying an altered p53 gene is able to modify cell tumorigenic properties. It is not known whether such an effect may also be achieved in thyroid cancer cells expressing wild-type p53, as in the majority of differentiated thyroid carcinomas. Effects of p53 transduction in a thyroid carcinoma cell line (FRO) exhibiting a wild-type endogenous p53 gene, in comparison to a cell line (WRO) exhibiting mutant p53, were investigated by using an inducible chimeric construct containing human p53 complementary DNA fused to the ligand binding domain of the estrogen receptor (p53ER). FRO cells were unaffected by exogenous p53 expression in terms of both proliferation and viability. On the contrary, p53 reexpression in WRO cells containing hemizygous mutated p53 allele caused a strong growth inhibition due to cell accumulation in the G1 phase of the cell cycle. In addition, exogenous p53 did not influence FRO cell behavior in response to TSH treatment or modify cell resistance to the chemotherapeutic agent, doxorubicin. Our results indicate that exogenous expression of wild-type p53 affects thyroid tumorigenic properties only in cells carrying an altered p53, whereas it is ineffective in cells expressing wild-type p53 activity. Therefore, the endogenous p53 status seems to be a major determinant for the effectiveness of a p53-based gene therapy for thyroid cancer.
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Genes p53/genética , Transducción de Señal/genética , Neoplasias de la Tiroides/genética , Antibióticos Antineoplásicos/farmacología , Antineoplásicos/farmacología , Western Blotting , Ciclo Celular , División Celular/fisiología , Cisteína Endopeptidasas/metabolismo , Doxorrubicina/farmacología , Genes Supresores de Tumor/genética , Humanos , Complejos Multienzimáticos/metabolismo , Plásmidos/genética , Complejo de la Endopetidasa Proteasomal , Células Tumorales CultivadasRESUMEN
Thyroid tumorigenesis proceeds through the progressive accumulation of alterations in genes involved in the regulation of cell proliferation and differentiation accompanying the acquisition of phenotypic, biological and clinical characteristics of increasing malignancy and dedifferentiation. The molecular alterations specific to thyrocyte carcinogenesis are examined. Ras mutations seem to represent an early occurrence in thyroid tumorigenesis being common to both benign and malignant follicular tumors; they would represent the early mutational events able to enhance the cell proliferation. Subsequent alterations in several genes will probably result in the determination of a follicular or papillary phenotype. In particular, mutational events activating ret, met and trk thyrokinase receptors direct the tumor growth and development towards the papillary type. Progression towards a follicular phenotype would instead occur in two stages: first there is the loss of function of genes on chromosome 11q13 which may direct the tumor cell towards the phenotype of follicular adenoma, second, there is the inactivation of the probable suppressor oncogene on chromosome 3p which might be fundamental in the transition from adenoma to follicular carcinoma. Undifferentiated or anaplastic tumors are characterized by the presence of p53 gene mutations.
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Neoplasias de la Tiroides/genética , División Celular/genética , Genes Supresores de Tumor/genética , Predisposición Genética a la Enfermedad , Sustancias de Crecimiento/genética , Humanos , Mutación , Fenotipo , Proto-Oncogenes/genética , Receptores de Tirotropina/genéticaRESUMEN
Tumours derived from the thyroid follicular epithelium represent an informative model for understanding the molecular pathogenesis of multistage tumourigenesis, which is the prevailing theory on cancer development and progression nowadays. The early stages of thyroid tumour development appear to be the consequence of the activation or 'de novo' expression of several proto-oncogenes or growth factor receptors, such as ras, ret, NTRK, met, gsp and the thyrotropin (TSH) receptor. Alterations in the expression pattern of these genes are associated with the development of differentiated neoplasms, ranging from benign toxic adenomas (gsp and TSH receptor), to follicular (ras) and papillary (ret/PTC, NTRK, met) carcinomas. They may all be considered to be early events of thyroid cell transformation and, for some, experimental evidence derived from gene transfer studies supports this hypothesis. Alterations in tumour suppressor genes (p53, Rb) are associated instead with the most aggressive and poorly differentiated forms of thyroid cancer, indicating that, in the thyroid tumourigenic process, they represent late genetic events. Specific environmental factors (iodine deficiency, ionizing radiations) have been shown to play a crucial role in promoting the development of thyroid cancer, influencing both its genotypic and phenotypic features. Interestingly, a high percentage of genetic lesions causing thyroid cancer originate from gene rearrangements and chromosomal translocations (ret/PTC, NTRK, Pax-8/PPARgamma) a finding which, being a rare event in most epithelial tumours, makes the molecular pathogenesis of thyroid cancer unique. The uninterrupted flow of information on the molecular genetics of thyroid nodules and cancer will broaden the correlation between genotype and phenotype and will also provide important information for the development of more accurate preoperative diagnostic tools and more efficient treatment choices for the different forms of thyroid cancer.
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Neoplasias de la Tiroides/genética , Nódulo Tiroideo/genética , Metilación de ADN , Genes Supresores de Tumor , Sustancias de Crecimiento , Humanos , OncogenesRESUMEN
We evaluated growth hormone (GH) secretion in 81 patients with Turner's syndrome (TS) (mean age 10.7+/-3.6 y) with respect to karyotype, auxological characteristics and growth response to GH treatment (1 IU/kg/wk). None of the patients had spontaneous puberty or had started replacement therapy with estrogens. Thirty-nine patients (48%) had monosomia 45X, 29 (36%) structural abnormalities of the X chromosome and 13 (16%) X mosaicism. Before the start of GH therapy, each patient underwent an evaluation of mean nocturnal GH concentration (MGHC) and 75 patients also underwent 2 pharmacological tests. MGHC of the TS patients did not differ from that of 29 prepubertal GH-deficient girls (GH peaks < 8 microg/l after pharmacological tests) and both groups were lower (p < 0.0001 and p < 0.0005, respectively) than MGHCs of 27 short normal girls (GH peak > 8 microg/l). MGHC of the patients with TS was negatively correlated (p < 0.001) with bodyweight excess (BWE) at multiple regression analysis. MGHC of the TS patients with BWE < 20% was significantly higher (p < 0.02) than that of the TS patients with BWE > 20%, but again did not differ from that of the GH-deficient patients and was lower (p < 0.001) than that of the short normal girls. MGHC did not significantly differ between the 3 groups subdivided according to karyotype. Forty-four percent of the TS patients showed GH responses to pharmacological tests < 8 microg/l. Height velocity SDS at first and second year of therapy was not influenced by MGHC levels, chronological or bone age, target height or BWE. In conclusion, spontaneous secretion in our patients with TS was lower than that of the short normal prepubertal girls and did not differ from that of GH-deficient subjects, even if we excluded overweight patients. The level of GH secretion was unable to predict GH response to treatment.
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Hormona de Crecimiento Humana/deficiencia , Hormona de Crecimiento Humana/metabolismo , Síndrome de Turner/metabolismo , Adolescente , Determinación de la Edad por el Esqueleto , Niño , Preescolar , Aberraciones Cromosómicas/genética , Trastornos de los Cromosomas , Dopaminérgicos , Síndrome de Down/complicaciones , Procesamiento Automatizado de Datos , Femenino , Trastornos del Crecimiento/complicaciones , Trastornos del Crecimiento/diagnóstico , Hormona de Crecimiento Humana/sangre , Hormona de Crecimiento Humana/uso terapéutico , Humanos , Cariotipificación , Levodopa , Masculino , Radioinmunoensayo , Síndrome de Turner/complicaciones , Síndrome de Turner/tratamiento farmacológico , Cromosoma X/genéticaRESUMEN
Coronary reocclusion is a frequent event after reperfusion and may be responsible for the deterioration of left ventricular function. It may occur early as well as in the chronic phase after hospital discharge. Current, evidence based, strategies to prevent reocclusion include antiplatelet and anticoagulant agents as well as the use of intracoronary stenting in those patients who are treated by PTCA. The combination of aspirin and ticlopidine adds on the results of stenting. Further treatments are currently investigated and may significantly improve the long-term coronary patency.
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Enfermedad Coronaria/tratamiento farmacológico , Reperfusión Miocárdica , Grado de Desobstrucción Vascular , Angioplastia Coronaria con Balón , Anticoagulantes/uso terapéutico , Aspirina/uso terapéutico , Enfermedad Coronaria/fisiopatología , Humanos , Inhibidores de Agregación Plaquetaria/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores de Tiempo , Resultado del Tratamiento , Warfarina/uso terapéuticoRESUMEN
Factor XII (FXII) is a liver-specific zymogen involved in the regulation of hemostasis, particularly in the activation of fibrinolysis. Transcription of the FXII gene is stimulated by estrogens through specific interaction of the estrogen receptor alpha (ER alpha) with an estrogen response element present on FXII promoter. Interestingly, the magnitude of ER alpha induction in liver HepG2 cells is much lower than in NIH3T3 fibroblasts, suggesting that cell-specific factors may modulate ER alpha-dependent trans-activation. Comparative footprinting analysis of FXII promoter (from nucleotides -181 to +49) in liver vs. non-liver cell environments allowed identification of four deoxyribonuclease I-protected sites only in the presence of HepG2 nuclear extracts. Computerized homology search identified sites III and IV as consensus binding sequences for the liver-enriched transcription factor hepatocyte nuclear factor-4 (HNF-4), formerly an orphan receptor belonging to the superfamily of steroid/thyroid hormone nuclear receptors. In transient transfection assays in NIH3T3 cells, HNF-4 significantly inhibited (70%) estrogen induction of FXII promoter while not affecting basal promoter activity. Conversely, HNF-4 did not inhibit estrogen inducibility of FXII promoter in HepG2 cells due to the high endogenous levels of HNF-4 protein. In gel shift assays, HNF-4, either present in HepG2 nuclear extracts or generated by in vitro transcription/translation, specifically bound FXII promoter. This interaction is strictly required in eliciting the antagonistic effect because in NIH3T3 cells, selective mutations of sites III and IV abrogated HNF-4 inhibitory properties. In the liver-specific environment, the same mutant construct exhibited higher estrogen-dependent inducibility compared with native promoter. Rescue of estrogen responsiveness was also achieved using a dominant negative HNF-4, which counteracted endogenous HNF-4 activity. In conclusion, our findings address a direct role for HNF-4 in modulating estrogen-dependent transcription of the FXII gene promoter.
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Proteínas de Unión al ADN , Factor XII/biosíntesis , Fosfoproteínas/farmacología , Receptores de Estrógenos/antagonistas & inhibidores , Factores de Transcripción/farmacología , Animales , Secuencia de Bases , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice , Western Blotting , Huella de ADN , Desoxirribonucleasas/metabolismo , Electroforesis en Gel de Poliacrilamida , Factor XII/genética , Regulación de la Expresión Génica/fisiología , Factor Nuclear 4 del Hepatocito , Humanos , Ratones , Datos de Secuencia Molecular , Plásmidos/genética , Regiones Promotoras Genéticas/genética , Receptores de Estrógenos/fisiología , TransfecciónRESUMEN
The change in the eating behaviour of anorexic individuals has been studied with particular attention to the case of two biovular heterozygotic twins. It is observed that dietetic treatment backed by careful psychiatric therapy is a decisive factor in the resolution of the pathology.