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Electrical behavior of cardiac muscle in abnormal conditions
91 ISOLATION OF DAMAGED MITOCHONDRIA D. R. Sanadi, DAMAGE IN AGING. ology, Boston Biomedical Research
R.
FROM HEART R. Murfitt. Institute,
AND
EVIDENCE FOR INCREASED Department of Cell PhysiBoston, Massachusetts, USA.
There is much evidence in the literature that mitochondrial oxidation and sometimes coupled phosphorylation, are decreased in aged rates, animals. (Sanadi, In: Handbook of Aging, C. E. Finch and L. Hayflick, eds.) A method has been devised for the separation of crude heart mitochondrial (M) samples in an isotonic density gradient containing KC1 and Metrizamide [2-(3-acetamido-5-N-methylacetamido-2,4,6-tri iodobenzamide)2-deoxy-D-g1 ucose] . Two distinct bands are obtained from young (Y) and old (0) heart M. The upper (U) band contains 35-40% and the lower (L) band IO% of the protein applied to the gradient. The rest is dispersed, This ratio holds for both MY and MO. The state presumably as particles. 3 rates were greater in MY than in MO before separation of bands (both with and without added cytochrome c (p
ELECTRICAL BEHAVIOR OF CARDIAC MUSCLE IN ABNORMAL CONDITIONS. T. Sano. Institute for Cardiovascular Diseases, Tokyo Medical and Dental University, Tokyo, Japan. Abnormal electrical behavior of heart muscle may be divided into spontaneous and triggered automaticity and re-entry, each consisting of fast and slow responses. Re-entry and slow response autanaticity have been stressed as the mechanism of most arrhythmia. In addition to many other known conditions, barium arrhythmia was found to be induced by slow response automaticity. Fast response arrhythmia has been neglected, but aconitine fibrillation was found to be one of its examples, no change being noticed in slow inward current. Fast and slow responses are divided by the voltage regions where they dominate, but at the intermediate voltages there is no clear distinction between the two. Approaching these voltages the activity of fast responses is depressed, but not SO slow as the slow response. such fast responses are probably most important as the mechanism of arrhythmia. A variety of such responses and abnormality of ionic current were found in each condition of abnormal cardiac metabolism. In low pH and excess Of lactates spontaneous fast response in Purkinje fibers and re-entry in Purkinje fibers, myocardial fibers or Purkinje-myocardial junction are important. Anoxia only was found to be a difficult condition in inducing re-entry, but it does when resting potential is lowered by combination of high K condition, for instance.
R.
FROM HEART R. Murfitt. Institute,
AND
EVIDENCE FOR INCREASED Department of Cell PhysiBoston, Massachusetts, USA.
There is much evidence in the literature that mitochondrial oxidation and sometimes coupled phosphorylation, are decreased in aged rates, animals. (Sanadi, In: Handbook of Aging, C. E. Finch and L. Hayflick, eds.) A method has been devised for the separation of crude heart mitochondrial (M) samples in an isotonic density gradient containing KC1 and Metrizamide [2-(3-acetamido-5-N-methylacetamido-2,4,6-tri iodobenzamide)2-deoxy-D-g1 ucose] . Two distinct bands are obtained from young (Y) and old (0) heart M. The upper (U) band contains 35-40% and the lower (L) band IO% of the protein applied to the gradient. The rest is dispersed, This ratio holds for both MY and MO. The state presumably as particles. 3 rates were greater in MY than in MO before separation of bands (both with and without added cytochrome c (p
ELECTRICAL BEHAVIOR OF CARDIAC MUSCLE IN ABNORMAL CONDITIONS. T. Sano. Institute for Cardiovascular Diseases, Tokyo Medical and Dental University, Tokyo, Japan. Abnormal electrical behavior of heart muscle may be divided into spontaneous and triggered automaticity and re-entry, each consisting of fast and slow responses. Re-entry and slow response autanaticity have been stressed as the mechanism of most arrhythmia. In addition to many other known conditions, barium arrhythmia was found to be induced by slow response automaticity. Fast response arrhythmia has been neglected, but aconitine fibrillation was found to be one of its examples, no change being noticed in slow inward current. Fast and slow responses are divided by the voltage regions where they dominate, but at the intermediate voltages there is no clear distinction between the two. Approaching these voltages the activity of fast responses is depressed, but not SO slow as the slow response. such fast responses are probably most important as the mechanism of arrhythmia. A variety of such responses and abnormality of ionic current were found in each condition of abnormal cardiac metabolism. In low pH and excess Of lactates spontaneous fast response in Purkinje fibers and re-entry in Purkinje fibers, myocardial fibers or Purkinje-myocardial junction are important. Anoxia only was found to be a difficult condition in inducing re-entry, but it does when resting potential is lowered by combination of high K condition, for instance.