Publications by authors named "Ronaldo H B Santos"

Chagas disease, caused by the protozoan , is an endemic parasitic disease of Latin America, affecting 7 million people. Although most patients are asymptomatic, 30% develop complications, including the often-fatal Chronic Chagasic Cardiomyopathy (CCC). Although previous studies have demonstrated some genetic deregulations associated with CCCs, the causes of their deregulations remain poorly described.

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Chronic Chagas disease (CCC) is an inflammatory dilated cardiomyopathy with a worse prognosis compared to other cardiomyopathies. We show the expression and activity of Matrix Metalloproteinases (MMP) and of their inhibitors TIMP (tissue inhibitor of metalloproteinases) in myocardial samples of end stage CCC, idiopathic dilated cardiomyopathy (DCM) patients, and from organ donors. Our results showed significantly increased mRNA expression of several MMPs, several TIMPs and EMMPRIN in CCC and DCM samples.

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Infection by the protozoan causes Chagas disease cardiomyopathy (CCC) and can lead to arrhythmia, heart failure and death. Chagas disease affects 8 million people worldwide, and chronic production of the cytokines IFN-γ and TNF-α by T cells together with mitochondrial dysfunction are important players for the poor prognosis of the disease. Mitochondria occupy 40% of the cardiomyocytes volume and produce 95% of cellular ATP that sustain the life-long cycles of heart contraction.

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Chagas disease cardiomyopathy (CCC) is an inflammatory dilated cardiomyopathy occurring in 30% of the 6 million infected with the protozoan in Latin America. Survival is significantly lower in CCC than ischemic (IC) and idiopathic dilated cardiomyopathy (DCM). Previous studies disclosed a selective decrease in mitochondrial ATP synthase alpha expression and creatine kinase activity in CCC myocardium as compared to IDC and IC, as well as decreased myocardial ATP production.

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Chronic Chagas disease cardiomyopathy (CCC), an especially aggressive inflammatory dilated cardiomyopathy caused by lifelong infection with the protozoan Trypanosoma cruzi, is a major cause of cardiomyopathy in Latin America. Although chronic myocarditis may play a major pathogenetic role, little is known about the molecular mechanisms responsible for its severity. The aim of this study is to study the genes and microRNAs expression in tissues and their connections in regards to the pathobiological processes.

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Background: Chagas disease, caused by the protozoan Trypanosoma cruzi, is endemic in Latin America and affects 10 million people worldwide. Approximately 12000 deaths attributable to Chagas disease occur annually due to chronic Chagas disease cardiomyopathy (CCC), an inflammatory cardiomyopathy presenting with heart failure and arrythmia; 30% of infected subjects develop CCC years after infection. Genetic mechanisms play a role in differential progression to CCC, but little is known about the role of epigenetic modifications in pathological gene expression patterns in CCC patients' myocardium.

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Long noncoding RNAs (lncRNAs) modulate gene expression at the epigenetic, transcriptional, and posttranscriptional levels. Dysregulation of the lncRNA known as myocardial infarction-associated transcript (MIAT) has been associated with myocardial infarction. Chagas disease causes a severe inflammatory dilated chronic cardiomyopathy (CCC).

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Background: Chronic Chagas disease cardiomyopathy (CCC), a late consequence of Trypanosoma cruzi infection, is an inflammatory cardiomyopathy with prognosis worse than those of noninflammatory etiology (NIC). Although the T cell-rich myocarditis is known to play a pathogenetic role, the relative contribution of each of the functional T cell subsets has never been thoroughly investigated. We therefore assessed gene expression of cytokines and transcription factors involved in differentiation and effector function of each functional T cell subset (TH1/TH2/TH17/Treg) in CCC, NIC, and heart donor myocardial samples.

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Background/methods: Chagas disease is caused by an intracellular parasite, Trypanosoma cruzi, and it is a leading cause of heart failure in Latin America. The main clinical consequence of the infection is the development of a Chronic Chagas disease Cardiomyopathy (CCC), which is characterized by myocarditis, hypertrophy and fibrosis and affects about 30% of infected patients. CCC has a worse prognosis than other cardiomyopathies, like idiopathic dilated cardiomyopathy (DCM).

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Background: Discrepancies between pre and post-mortem diagnoses are reported in the literature, ranging from 4.1 to 49.8 % in cases referred for necropsy, with important impact on patient treatment.

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Aims: Chagas disease, caused by the protozoan Trypanosoma cruzi is endemic in Latin America, and may lead to a life-threatening inflammatory dilated, chronic Chagas cardiomyopathy (CCC). One third of T. cruzi-infected individuals progress to CCC while the others remain asymptomatic (ASY).

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Background: Chronic Chagas cardiomyopathy (CCC), a life-threatening inflammatory dilated cardiomyopathy, affects 30% of the approximately 8 million patients infected by Trypanosoma cruzi. Even though the Th1 T cell-rich myocarditis plays a pivotal role in CCC pathogenesis, little is known about the factors controlling inflammatory cell migration to CCC myocardium.

Methods And Results: Using confocal immunofluorescence and quantitative PCR, we studied cell surface staining and gene expression of the CXCR3, CCR4, CCR5, CCR7, CCR8 receptors and their chemokine ligands in myocardial samples from end-stage CCC patients.

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Background: Chronic Chagas disease cardiomyopathy (CCC) is an inflammatory dilated cardiomyopathy with a worse prognosis than other cardiomyopathies. CCC occurs in 30 % of individuals infected with Trypanosoma cruzi, endemic in Latin America. Heart failure is associated with impaired energy metabolism, which may be correlated to contractile dysfunction.

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Background: The aim of this study was to evaluate the degree of tricuspid valve insufficiency after orthotopic cardiac transplantation with bicaval anastomosis and prophylactic donor heart annuloplasty.

Methods: At present, our cardiac transplantation experience includes 478 cases. After January 2002, we included 30 consecutive patients in this study who had undergone orthotopic cardiac transplantation and survived >6 months.

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Objectives: With the increase in life expectancy occurred in recent decades, it has been noted the concomitant increase in the prevalence of aortic stenosis and degenerative disease of atherosclerotic coronary artery. This study aims to evaluate the influence of atherosclerotic coronary artery disease in patients with critical aortic stenosis undergoing isolated or combined implant valve prosthesis and coronary artery by pass grafting.

Methods: In the period of January 2001 to March 2006, there were analyzed 448 patients undergoing isolated implant aortic valve prosthesis (Group I) and 167 patients undergoing aortic valve prosthesis implant combined with coronary artery bypass grafting (Group II).

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Background: Pulmonary hypertension (PH) is a factor of poor prognosis in the postoperative period of heart transplant (HT) and thus, the study of the degree of reversibility to vasodilators is mandatory during the preoperative assessment.

Objective: To evaluate the pulmonary and systemic hemodynamic effects of sildenafil as a vasodilator during the PH reversibility test in patients that are candidates to HT.

Methods: Patients awaiting HT were submitted to the measurement of systemic and pulmonary hemodynamic variables before and after the administration of a single sublingual dose of 100 mg of sildenafil during right heart catheterization.

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Objective: This study aims to evaluate the effects of prophylactic heart donor tricuspid annuloplasty in patients after heart transplantation with bicaval anastomosis.

Methods: From 2002 to 2005, 20 patients undergoing heart transplantation with bicaval anastomosis and with a survival rate over 6 months were deliberately selected. Patients were divided into two groups: Group I - 10 patients who underwent prophylactic heart donor tricuspid annuloplasty by the De Vega technique; and Group II - 10 patients did not undergo annuloplasty.

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