Contractility of myofibrils from the heart and diaphragm muscles measured with atomic force cantilevers: effects of heart-specific deletion of arginyl-tRNA-protein transferase.

BACKGROUND: Contractile properties of myofibrils from the myocardium and diaphragm in chronic heart failure are not well understood. We investigated myofibrils in a knockout (KO) mouse model with cardiac-specific deletion of arginyl-tRNA-protein transferase (α-MHCAte1), which presents dilated cardiomyopathy and heart failure. OBJECTIVE: The aim of this study was to test the hypothesis that chronic heart failure in α-MHCAte1 mice is associated with abnormal contractile properties of the heart and diaphragm. METHODS: We used a newly developed system of atomic force cantilevers (AFC) to compare myofibrils from α-MHCAte1 and age-matched wild type mice (WT). Myofibrils from the myocardium and the diaphragm were attached to the AFC used for force measurements during activation/deactivation cycles at different sarcomere lengths. RESULTS: In the heart, α-MHCAte1 myofibrils presented a reduced force during full activation (89±9 nN/µm(2)) when compared to WT (132±11 nN/µm(2)), and the decrease was not influenced by sarcomere length. These myofibrils presented similar kinetics of force development (K(act)), redevelopment (K(tr)), and relaxation (K(rel)). In the diaphragm, α-MHCAte1 myofibrils presented an increased force during full activation (209±31 nN/µm(2)) when compared to WT (123±20 nN/µm(2)). Diaphragm myofibrils of α-MHCAte1 and WT presented similar K(act), but α-MHCAte1 myofibrils presented a faster K(rel) (6.11±0.41s(-1) vs 4.63±0.41 s(-1)). CONCLUSION: Contrary to our working hypothesis, diaphragm myofibrils from α-MHCAte1 mice produced an increased force compared to myofibrils from WT. These results suggest a potential compensatory mechanism by which the diaphragm works under loading conditions in the α-MHCAte1 chronic heart failure model.

A rare case of primitive right atrium angio-sarcoma with favorable outcome, in a young female: case report and literature review / Angiosarcoma primitivo de la aurícula derecha en una mujer joven, con respuesta favorable al tratamiento: reporte de un caso y revisión de la literatura

Primary malignant cardiac tumors are extremely rare, but their associated mortality is very high. The clinical presentation is oñen variable and nonspecific; by the time symptoms appear, the tumor has usually evolved to a large intracardiac and paracardiac mass causing considerable hemodynamic involvement, regional invasión and distant dissemination. We report a 26 year-old female with a right atrium angiosarcoma with a surprisingly favorable outcome at 2 years follow-up after treatment with a combination of neoadjuvant chemotherapy and surgical resection. She presented with chest tightness, shortness of breath at effort, atypical chest pain, palpitations, asthenia, weight loss and profuse perspiration. Physical examination and irnaging diagnostic procedures, identified a pericardial effusion and a pathologic cardiac mass. The diagnosis of a malignant angiosarcoma was suggested afier computed tomography transthoracic and transesophageal echocardiography It was confirmed at surgery by a biopsy followed by histopathology and immunohistochemistry.

Los tumores cardíacos malignos son extremadamente raros y su mortalidad es muy alta. El cuadro clínico es variable e inespecífico: frecuentemente cuando aparecen síntomas ya existe una gran masa intracardíacayparacardíaca que causa compromiso hemodinámico grave, además de invasión locorregionaly diseminación a distancia. Comunicamos un caso especial de una mujerjoven que tuvo una evolución sorprendentemente favorable después de un tratamiento combinado con quimioterapia neoadyuvante y resección quirúrgica. La paciente presentó opresión precordial, disnea de esfuerzo, dolor torácico atípico, palpitaciones, astenia, baja de peso y sudoración profusa. El examen físico y exámenes complementarios, especialmente de imágenes, identificaron un derrame pericárdico y una masa cardíaca patológica. La tomografía computada y la ecocardiografía, particularmente la transesofágica, sugirieron el diagnóstico de angiosarcoma maligno, que se confirmó en una intervención quirúrgica que incluyó una biopsia con estudios histopatológicos e inmunohistoquímicos. Se discuten las alternativas del diagnóstico y del tratamiento, y se revisan la epidemiología y los recursos terapéuticos actuales en la literatura. Este caso ilustra la utilidad de la ecocardiografía transesofágica, para el diagnóstico de estos tumores y se plantea que el uso de nuevas alternativas quimioterapias asociadas a la extirpación quirúrgica pueden mejorar la sobrevida que, en nuestra paciente, alcanza dos años libre de síntomas.

A rare case of primitive right atrium angio-sarcoma with favorable outcome, in a young female. Case report and literature review.

Primary malignant cardiac tumors are extremely rare, but their associated mortality is very high. The clinical presentation is oñen variable and nonspecific; by the time symptoms appear, the tumor has usually evolved to a large intracardiac and paracardiac mass causing considerable hemodynamic involvement, regional invasión and distant dissemination. We report a 26 year-old female with a right atrium angiosarcoma with a surprisingly favorable outcome at 2 years follow-up after treatment with a combination of neoadjuvant chemotherapy and surgical resection. She presented with chest tightness, shortness of breath at effort, atypical chest pain, palpitations, asthenia, weight loss and profuse perspiration. Physical examination and irnaging diagnostic procedures, identified a pericardial effusion and a pathologic cardiac mass. The diagnosis of a malignant angiosarcoma was suggested afier computed tomography transthoracic and transesophageal echocardiography It was confirmed at surgery by a biopsy followed by histopathology and immunohistochemistry.