RESUMO
Hypertrophic cardiomyopathy (HCM) is an inherited cardiovascular disease (CD) that commonly causes an increased size of cardiomyocytes in the left ventricle. The proteins myosin and actin interact in the myocardium to produce contraction through the actomyosin ATPase cycle. The duty ratio (r) of myosin is the proportion of the actomyosin ATPase cycle that myosin is bound to actin and does work. A common hypothesis is that HCM mutations increase contraction in cardiac sarcomeres; however, the available data are not clear on this connection. Based on previous work with human α-cardiac actin (ACTC), we hypothesize that HCM-linked ACTC variants with alterations near the myosin binding site have an increased r, producing more force. Myosin duty ratios using human ACTC variant proteins were calculated with myosin ATPase activity and in-vitro motility data. We found no consistent changes in the duty ratio of the ACTC variants, suggesting that other factors are involved in the development of HCM when ACTC variants are present.
Assuntos
Actinas/metabolismo , Actomiosina/metabolismo , Cardiomiopatia Hipertrófica/metabolismo , Miosinas/metabolismo , Actinas/genética , Sítios de Ligação , HumanosRESUMO
Caso clínico: Presentamos, dada su rareza, un caso deinvaginación del sigmoide crónica sin aparente causa orgánicasubyacente de intususcepción, de más de 10 años deevolución, que fue interpretado como una neoplasia malignade colon izquierdo, termina como un cuadro de oclusiónintestinal y muere finalmente en un fallo múltiple de órganos.Discusión: Se revisa brevemente la literatura (AU)
We present a rare case of a chronic sigmoid intussusceptionwith no apparent underlying organic cause. Itevolved over 10 years and was missinterpreted as a malignantneoplasm in the left colon. The final clinical picturewas that of intestinal occlusion. The patient died in multiorganfailure. Discussion: The literature is briefly reviewed (AU)
