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1.
Circulation ; 96(6): 2031-7, 1997 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-9323096

RESUMO

BACKGROUND: Immune dysfunction has long been proposed as a mechanism for the etiopathogenesis of the chronic phase of Chagas' disease. Antibodies of chagasic patients have been shown to interfere with electric and mechanical activity of embryonic myocardial cells in culture. Here, we demonstrate that antibodies derived from a group of chronic chagasic patients are able to induce disturbances in the electrogenesis and conduction in isolated adult rabbit hearts. METHODS AND RESULTS: Sera from chronic chagasic patients with complex cardiac arrhythmias (ChA+) decreased heart rate (from 131+/-26 to 98+/-37 bpm [mean+/-SD]; n=6; P<.05) in isolated rabbit hearts when perfused at a dilution of 1:100 (vol:vol) by the Langendorff method. Sera from another experimental group of four chronic chagasic patients without complex arrhythmias (ChA-) and two control groups composed of five Wolff-Parkinson-White (WPW) syndrome patients and five orthopedic surgery patients did not affect heart rate when tested under similar conditions. In addition, sera from five of six ChA+ patients and from one WPW patient induced AV conduction blockade. Effects of the sera from ChA+ patients are due to their IgG fractions. Both serum and IgG effects are blocked by atropine (10 micromol/L). CONCLUSIONS: Antibodies of ChA+ patients decrease heart rate and induce AV conduction block in isolated adult rabbit hearts through activation of muscarinic receptors.


Assuntos
Anticorpos Antiprotozoários/imunologia , Cardiomiopatia Dilatada/fisiopatologia , Cardiomiopatia Chagásica/imunologia , Doença de Chagas/imunologia , Bloqueio Cardíaco/fisiopatologia , Síndrome de Wolff-Parkinson-White/fisiopatologia , Adulto , Animais , Nó Atrioventricular/efeitos dos fármacos , Nó Atrioventricular/imunologia , Nó Atrioventricular/fisiopatologia , Atropina/farmacologia , Cardiomiopatia Dilatada/imunologia , Cardiomiopatia Dilatada/parasitologia , Cardiomiopatia Chagásica/fisiopatologia , Doença de Chagas/sangue , Doença Crônica , Eletrocardiografia , Eletrofisiologia , Feminino , Bloqueio Cardíaco/imunologia , Bloqueio Cardíaco/parasitologia , Frequência Cardíaca , Humanos , Imunoglobulina G/farmacologia , Técnicas In Vitro , Masculino , Pessoa de Meia-Idade , Antagonistas Muscarínicos/farmacologia , Coelhos , Síndrome de Wolff-Parkinson-White/imunologia , Síndrome de Wolff-Parkinson-White/parasitologia
2.
Acta Histochem ; 99(2): 187-93, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9248576

RESUMO

Expression and distribution of atrial natriuretic peptide (ANP) were studied immunohistochemically in the conducting system and internodal atrial myocardium of 5 adult human hearts. Myocytes from the sinus node and compact atrioventricular node were usually ANP-negative; only a very few cells exhibited ANP immunoreactivity. These ANP-positive myocytes were small and did not appear to be trapped working atrial myocytes which are larger than nodal cells. The transitional cell zones of the sinus node and the atrioventricular node were composed of bundles of ANP-positive myocytes, intermingled with non-reactive myocytes. The internodal atrial myocardium exhibited a comparable intensity of myocyte staining in each case examined. Thus, morphologically distinct connecting pathways between the sinus node and the atrioventricular node with regard to myocyte ANP immunoreactivity could not be demonstrated, reinforcing the notion that they actually do not exist. The penetrating bundle, branching bundle and bundle branches were usually composed of ANP-negative myocytes although some ANP-positive myocytes were observed in the branching bundle and bundle branches in 4 cases. Myocytes from the ventricular conducting tissue presenting ANP immunoreactivity have been designated Purkinje fibers and have been found in several mammalian species.


Assuntos
Fator Natriurético Atrial/química , Sistema de Condução Cardíaco/química , Miocárdio/química , Miocárdio/citologia , Adulto , Idoso , Nó Atrioventricular/química , Nó Atrioventricular/citologia , Nó Atrioventricular/imunologia , Feminino , Átrios do Coração/química , Átrios do Coração/citologia , Átrios do Coração/imunologia , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Miocárdio/imunologia , Nó Sinoatrial/química , Nó Sinoatrial/citologia , Nó Sinoatrial/imunologia
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