Cytokine production but lack of proliferation in peripheral blood mononuclear cells from chronic Chagas' disease cardiomyopathy patients in response to T. cruzi ribosomal P proteins.

BACKGROUND: Trypanosoma cruzi ribosomal P proteins, P2ß and P0, induce high levels of antibodies in patients with chronic Chagas' disease Cardiomyopathy (CCC). It is well known that these antibodies alter the beating rate of cardiomyocytes and provoke apoptosis by their interaction with ß1-adrenergic and M2-muscarinic cardiac receptors. Based on these findings, we decided to study the cellular immune response to these proteins in CCC patients compared to non-infected individuals. METHODOLOGY/PRINCIPAL FINDINGS: We evaluated proliferation, presence of surface activation markers and cytokine production in peripheral blood mononuclear cells (PBMC) stimulated with P2ß, the C-terminal portion of P0 (CP0) proteins and T. cruzi lysate from CCC patients predominantly infected with TcVI lineage. PBMC from CCC patients cultured with P2ß or CP0 proteins, failed to proliferate and express CD25 and HLA-DR on T cell populations. However, multiplex cytokine assays showed that these antigens triggered higher secretion of IL-10, TNF-α and GM-CSF by PBMC as well as both CD4+ and CD8+ T cells subsets of CCC subjects. Upon T. cruzi lysate stimulation, PBMC from CCC patients not only proliferated but also became activated within the context of Th1 response. Interestingly, T. cruzi lysate was also able to induce the secretion of GM-CSF by CD4+ or CD8+ T cells. CONCLUSIONS/SIGNIFICANCE: Our results showed that although the lack of PBMC proliferation in CCC patients in response to ribosomal P proteins, the detection of IL-10, TNF-α and GM-CSF suggests that specific T cells could have both immunoregulatory and pro-inflammatory potential, which might modulate the immune response in Chagas' disease. Furthermore, it was possible to demonstrate for the first time that GM-CSF was produced by PBMC of CCC patients in response not only to recombinant ribosomal P proteins but also to parasite lysate, suggesting the value of this cytokine to evaluate T cells responses in T. cruzi infection.

Short-term amiodarone therapy after reversion of persistent atrial fibrillation reduces recurrences at 18 months.

BACKGROUND: The aim of this study was to compare the outcome of 3 months vs. 18 months of amiodarone treatment after atrial fibrillation (AF) conversion in patients who experienced the first episode of persistent AF. METHODS: We included 51 patients who experienced the first episode of persistent AF receiving amiodarone (600 mg) daily for 4-6 weeks. If AF persisted, electrical cardioversion (ECV) was performed. All patients received amiodarone (200 mg daily) for 3 months and then were randomized to amiodarone (Group I) or placebo (Group II) and followed for 15 months. The control group comprised 9 untreated patients undergoing ECV. Treatment effectiveness was evaluated using a Bayesian model. RESULTS: Eighteen months after AF reversion, 22 (81.5%) patients in Group I, 13 (54.2%) patients in Group II, and 1 (11.1%) patient in the control group remained in sinus rhythm. No differences were found between Group I patients who required ECV and Group II patients. Sinus rhythm was preserved in all Group I patients when it was achieved during amiodarone administration. Limiting adverse effects occurred in 3 (11.1%) patients in Group I. CONCLUSIONS: In patients regaining sinus rhythm after the first episode of persistent AF, a 3-month amiodarone treatment after reversion is a reasonable option for rhythm control.

Análise experimental da resistência dos nós na osteossíntese tipo banda de tensão / Experimental analysis of knot resistance in tension band osteosynthesis

Introdução: Realizou-se estudo experimental com objetivo de avaliar a resistência de nós de fios metálicos confeccionados com tensionador de fios AO-ASIF (Grupo 1) comparados àqueles realizados com torção manual (Grupo 2), na síntese do tipo tirante de tensão. Método: Foram utilizados 28 corpos-de-prova de nylon 6,6 com 32 mm de diâmetro e 50 cm de comprimento com uma secção transversal incompleta de 27 mm no centro, formando uma zona de tensão na face íntegra do tarugo. Os fios foram aplicados aos tarugos e dois tipos de nós foram utilizados (Grupos 1 e 2). O conjunto foi montado em máquina de ensaios mecânicos de tração/compressão até fadiga da síntese, com mensuração da tensão. Resultados: O resultado estatístico da tensão no momento de fadiga, segundo média, desvio padrão, mediana, tensão mínima e máxima, demonstrou que o grupo 1 possui um nó 50% menos resistente à distração que o grupo 2. Conclusão: Os resultados mostraram que o tensionador de fios AO-ASIF produz um nó cerca de 50% menos resistente à distração quando comparado ao nó de torção manual.

Introduction: An experimental study aiming at evaluating the resistance of metallic threads knots made using a thread tensionator AO-ASIF (Group 1) was accomplished in order to compare them to those made with manual torsion (Group 2) in the tension strut type synthesis. Method: Twenty-eight proof bodies were used. They consisted of nylon 6.6 with 32 mm of diameter and 50 cm of length with an incomplete transversal section of 27 mm in the center, forming a tension zone in the pin?s complete face. The threads were applied to the pins and two-knot types were used (Groups 1 and 2). The proof body and cerclage were set up in a traction/compression mechanical assays machine till synthesis fatigue, measuring the tension. Results: Tension statistical results obtained in the fatigue moment, using the average, deviation standard, medium, minimum and maximum tension, demonstrated that Group 1 has a knot 50% less resistant to the distraction than Group 2. Conclusion: The results showed that the thread tensionator AO-ASIF produces a knot almost 50% less resistant to the distraction when compared to the manual torsion knot.

Pharmacologic reversion of persistent atrial fibrillation with amiodarone predicts long-term sinus rhythm maintenance.

OBJECTIVE: The study analyzed the role of different variables that determine long-term sinus rhythm maintenance in patients with persistent atrial fibrillation who are treated with amiodarone. BACKGROUND: It has been recognized that different factors influence long-term sinus rhythm preservation after the conversion of persistent atrial fibrillation. Although the duration of the arrhythmia appears to be the most important factor, consistent information regarding the role of the mode of arrhythmia conversion (pharmacologic or electric) is still lacking. METHODS: One hundred and forty one anticoagulated patients with persistent atrial fibrillation (median duration 8 months, percentiles 25 and 75: 2-24) were treated for 4 weeks with oral amiodarone (600 mg/day). Those in whom the arrhythmia persisted underwent electric cardioversion. After restoration of normal sinus rhythm (either pharmacologic or electric), all patients received a daily dose of amiodarone (200 mg) and were followed for a median of 19 months (percentiles 25 and 75: 8-34 months). RESULTS: Sixty eight patients (48.22%) regained sinus rhythm during the initial period of amiodarone treatment with 600 mg/day (Group I) and 73 (51.78%) required electric cardioversion (Group II). During the entire follow-up, atrial fibrillation relapsed in 63 patients: 17 (25%) in Group I and 46 (63%) in Group II. Recurrences of the arrhythmia were strikingly less frequent in patients whose atrial fibrillation lasted 12 months or less (33/103, 32.3%) than in those whose atrial fibrillation lasted more than 12 months (30/38, 78.94%). In the multivariate analysis, the mode of reversion (HR, 0.37; CI, 0.21-0.65) and the duration of the arrhythmia (HR, 2.55; CI, 1.54-4.20) were the determinants for long-term sinus rhythm maintenance. Age, sex, left atrium size, left ventricle diameter, and the shortening fraction did not significantly influence the rate of arrhythmia recurrence. Among the 141 patients included in the study, 113 patients were followed for at least 1 year, and cardiac rhythm was assessed at this time. Of these, only 1 of 48 patients (2.1%) in Group I was in atrial fibrillation, in marked contrast with 18 of 65 patients (27.8%) in Group II (RR, 0.075; 95% CI, 0.01-0.54). CONCLUSIONS: In patients with persistent atrial fibrillation, long-term preservation of sinus rhythm under chronic amiodarone treatment may be anticipated when the arrhythmia lasts 12 months or less and/or its reversion is obtained pharmacologically. We may confidently assume that these two factors have a beneficial additive influence on the outcome.