虚血心筋の心筋代謝に関する研究 : (II)電子スピン共鳴法による研究

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The intracellular oxydation reduction reaction is summed up to binding of hydrogen and oxygen into water through the electron transport system. ATP which is a key member of energy supplying agents is produced mainly by this electron transport system. From these facts it may be considered that significant changes of cardiac function will be induced by myocardial ischemia. The electron spin resonance (ESR) study has been used as a medical and biological technique which has been able to give us clues for clarifying the biochemical reaction mechanisms. The purpose of this paper is to examine the usefullness of ESR as an index of myocardial hypoxia. Method Twenty four adult mongrel dogs were used. The methods of production of myocardial ischemia and blood sampling study were almost same as described in Part I. Coronary artery and sinus blood were centrifuged (3000/min, 5 min) to separate plasma which was soon frozen by dipping the container into aceton dryice. Heart muscle was thrown into liquid nitrogen soon after cutting off. The frozen muscle was then powdered with liquid nitrogen in a mortar. The frozen powdered plasma or muscle was dried by the freezing desiccator. Suction period was about 1.5 hours in cases of the plasma sample, and 3 hours in cases of the muscle sample. The dried materials were packed into the special glass tube for ESR spectrometry, then weighed, and stored in a refrigerator at -20℃. JES-3BS-X type ESR spectrometer was used to obtain the ESR signal which was a differential curve of a free radical concentration curve. In this paper ESR intensity was calculated as follows : ESR intensity = the hight of signal from a material / the hight of signal from a standard substance. MnCl_2 was used as a standard substance. Result and Discussion The intensity of ESR signal may be influenced by many factors, such as hemolysis, leaving period of materials at room temperature, suction duration of vacuum pump, and condition of ESR equipment. ESR signals in this experiment were stable within 0.2% of hemolytic percentage, within 60 minutes of leaving at room temperature, within 28 days of storage at -20℃. There were about 10% standard error of ESR intensities which were obtained from 6 samples of the same material and about 6 % standard error of ESR intensities which were obtained from 6 time estimation of the same sample. In normal condition coronary A-V difference of ESR intensity showed no significant tendency. ESR intensities of normal heart muscle (mean 1.011) were greater than that of normal plasma (mean 0.349). During ischemic condition coronary A-V difference of ESR intensity tended to release from the myocardium. From these data it is suggested that free radical concentration increases in the ischemic myocardium where there may be disturbance in the electron transport system. Although free radicals can appear in many biochemical reactions in the living cells, free radicals in this experiment can originate from the intramitochondrial electron transport system, especially from flavin enzymes, taking the bibliographical data into consideration. Some medica-ments were administered intravenously 30 minutes after the onset of ischemia. Coronary A-V difference of ESR intensity tended to increase of release after epirenamine hydrochloride injection, whereas it tended to decrease of release after dipyridamole or theophylline ethylenediamine injection. All these medicaments increase the coronary flow in some ways. It may be considered that ESR signals reflect mainly the relative smoothness of oxygenation of the myocardium. Summary 1, ESR intensities of normal heart muscle were greater than that of normal plasma. Greater ESR intensities were found in the ischemic muscle and plasma than that in normal muscle and plasma. Coronary A-V difference of ESR intensity tended to increase of release after epirenamine hydrochloride injection and to decrease of release after dipyridamole, theophylline ethylendiamine injection.
社団法人日本循環器学会の論文
1969-04-20

虚血心筋の心筋代謝に関する研究 : (II)電子スピン共鳴法による研究

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