Action of burn serum on electrical and contractile activity of the homoiothermic myocardium

In experiments on isolated rabbit papillary muscles the action of burn serum (BS) obtained 1 h after thermal injury to rabbits was studied. During stimulation varying in frequency between 0.1 and 2 Hz isometric contractions and action potentials (AP) of myocardial cells were recorded. BS (diluted 1:1 in Tyrode solution) inhibited the contractile activity of the papillary muscles, increased the duration of AP, and reduced the duration of the contractile response. Inotropic effects on the rhythm of contractions remained unchanged: An increase in the frequency of stimulation to 2 Hz led to an increase in the amplitude of contractions. Inhibition of the contractile response increased progressively with an increase in the duration of perfusion of the preparations with BS. Addition of 6.4 mM Ca⁺⁺ to the solution of BS caused only a temporary increase in contractions, and rinsing the preparations with Tyrode solution did not result in complete recovery of the orginal contractions. It is concluded that humoral factors play an important role in the disturbance of the contractile properties of heart muscle during burn shock.Laboratory of Biophysical Research, A. V. Vishnevskii Institute of Surgery, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR M. I. Kuzin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 8, pp. 157–159, August, 1979.     

Antistressor effect of dalargin in rats with immobilization stress

Laboratory of Experimental Surgery, A. V. Vishnevskii Institute of Surgery, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR M. I. Kuzin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 111, No. 6, pp. 617–619, June, 1991.     

Postextrasystolic potentiation does not distinguish ischaemic from stunned myocardium

Myocardial function is impaired by ischaemia, and it remains depressed during reperfusion following short periods of ischaemia (stunned myocardium). We tested whether ischaemic and reperfusion dysfunction, in particular the time course of its recovery, can be distinguished by postextrasystolic potentiation (PESP). In eight open-chest dogs, posterior systolic wall thickening (sonomicrometry) was reduced by graded occlusion of the left circumflex coronary artery (LCX) from 17.4±6.8% (SD) during control conditions to 10.7±1.3% (mild ischaemic dysfunction), 7.2±2.3% (moderate ischaemic dysfunction), 3.6±1.4% (severe ischaemic dysfunction), and -4.4±3.6% (complete coronary occlusion). Extrasystoles with constant prematurity and a fully compensated postextrasystolic interval were induced after at least 4 min steady-state ischaemia. After each ischaemic period full recovery of posterior systolic wall thickening was assured. During 8 h of reperfusion following a 15-min LCX occlusion, extrasystoles were induced when posterior systolic wall thickening was comparable to one degree of the preceding ischaemic dysfunction. The increases in posterior systolic wall thickening induced by PESP were 10.5±5.8% during control conditions, during ischaemia they were 11.5±3.5% (mild dysfunction), 12.3±4.6% (moderate dysfunction), 12.6±4.1% (severe dysfunction) and 10.4±4.4% (complete coronary occlusion), and during reperfusion they were 12.8±8.2% (severe dysfunction), 13.0±9.7% (moderate dysfunction) and 10.7±2.2% (mild dysfunction). These increments in systolic wall thickening as well as those in ejection thickening were not significantly different. PESP can thus not distinguish between ischaemic and reperfusion dysfunction nor between different degrees of myocardial dysfunction.This study was supported by the Deutsche Forschungsge-meinschaft (He 1320/3-2). cand. med. S. Schäfer was involved in some of these experiments and presented part of the data at the 56th Annual Meeting of the Deutsche Gesellschaft für Herz- und Kreislaufforschung in Mannheim (Z Kardiol 79 [Suppl 1]: 24,1990). Part of the data were also presented at the 11th Congress of the European Society of Cardiology in Nice (Eur Heart J 10 [Suppl]: 242, 1989) and at the 73rd Annual Meeting of the Federation of American Societies for Experimental Biology in New Orleans (FASEB J 3: A841, 1989)     

Monoclonal antibodies cross-reacting with fibroblasts of myocardial interstitial connective tissue and with group a streptococcal cell wall protein antigens

N. F. Gamaleya Research Institute of Epidemiology and Microbiology. Institute of Rheumatology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR, P. A. Vershilova.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 108, No. 7, pp. 74–76, July, 1989.     

Ultrastructural features of the myocardium of newborn mini-pigs after chronic parental alcoholization

Department of Mini-Pig Models, Research Laboratory of Experimental Biological Models, Academy of Medical Sciences of the USSR, Krasnogorsk, Moscow Region. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 109, No. 4, pp. 398–400, April, 1990.     

Noradrenalin and adrenalin content in the human myocardium after accidental and sudden death

To investigate the mechanisms of sudden death the authors determined the noradrenalin and adrenalin content in the myocardium of various parts of the heart by a fluorometric method; parallel determinations were made in the myocardium of persons dying accidentally. A heterotopic distribution of noradrenalin in the various parts of the heart after sudden death was found compared with its distribution after accidental death. Differences in the content of adrenalin and noradrenalin in the various parts of the heart of the two groups indicate that death was due to different mechanisms.Laboratory of Pathophysiology, Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 8, pp. 153–156, August, 1978.     

不同部位缺血预处理对未成熟心肌保护作用的研究

目的探讨不同部位缺血预处理对未成熟心肌保护作用。方法采用经典心脏缺血预处理、肾缺血预处理及双下肢缺血预处理动物Langendorff灌注模型比较三种方法对缺血 /再灌(I/R)未成熟心肌损伤的效应。分为5组 :正常对照组(NC,n=6) ,离体心脏仅灌注KH液70min;缺血 /再灌 (I/R ,n=6) ,离体心脏灌注15min转为工作心15min后停灌45min,恢复灌注15min改为工作心30min;心脏缺血预处理组 (IPC,n=6),离体心脏灌注15min转为工作心15min后反复2次缺血5min/再灌5min,然后重复I/R组方法 ;肾缺血预处理组(K -IPC ,n=6) ,反复3次阻断左肾动脉5min,放开5min,然后重复I/R组方法。双下肢缺血预处理组 (DL-IPC ,n=6) ,反复3次捆扎双下肢5min,松开5min,然后重复I/R组方法。以左心室功能恢复、心肌含水量、血清肌酸激酶 (CK)和乳酸脱氢酶 (LDH)漏出率 ,心肌组织ATP和丙二醛 (MDA)含量、超氧化物歧化酶(SOD)活性及电镜作为观察指标。结果IPC、DL-IPC及K-IPC组在左心室功能恢复优于I/R组 (P<0.05) ,在ATP含量、SOD活性及心肌超微结构方面均优于I/R组(P<0.01) ,心肌含水量低于I/R组 (P<0.05) ,在MDA含量、CK、LDH漏出率方面均低于I/R组 (P<0.01)。结论不同部位的非心脏缺血预处理 ,与心脏缺血预处理可诱发同等的心肌保护作用     

机械牵张对大鼠心室肌蛋白激酶B磷酸化及心钠素分泌的影响

目的:研究机械牵张对大鼠心肌蛋白激酶B(Akt)活化和心钠素(ANF)分泌的影响。方法:采用Langendorff方法灌流大鼠心脏,膨胀球囊持续牵张左心室,从左心室游离心肌,提取胞浆蛋白,用Western blot检测磷酸化Akt、总Akt水平;收集冠脉流出液,用放射免疫分析法检测冠脉流出液中ANF含量。结果:持续牵张不影响灌流心脏的心率和冠脉流出量。但经过20min持续牵张,牵张组心脏灌流液中ANF含量(209.89±65.45pg/ml)较对照组(108.84±25.18pg/ml)明显增高(P<0.01);牵张组大鼠左心室心肌组织磷酸化Akt水平(0.76±0.03)明显高于对照组(0.32±0.02),而总Akt水平与对照组相比无显著性差异。结论:机械牵张可引起心脏心钠素的分泌增加,其机制可能与胞内Akt信号通路的激活有关。