Activities of creatine kinase isoenzymes in single skeletal muscle fibres of trained and untrained rats

Biochemical changes in the creatine kinase isoenzyme compositions in single muscle fibres of different types in rats were induced by endurance running training. Single muscle fibres were dissected from the soleus and extensor digitorum longus muscles of Wistarstrain male rats trained on a motor-driven treadmill for 16 weeks. Each fibre was typed histochemically (SO, slow-twitch oxidative; FOG, fast-twitch oxidative glycolytic; FG, fast-twitch glycolytic), and the activities of total creatine kinase and its four isoenzymes (CK-MM, -MB,-BB, and mitochondrial creatine kinase) were measured. The endurance training did not affect the total creatine kinase activity, but resulted in significantly increased activities of CK-MB and CK-BB in SO and FOG fibres, and the mitochondrial enzyme activity in FOG and FG fibres. Endurance training induced biochemical changes in the isoenzyme compositions, specifically in FOG fibres. These results suggest that changes in creatine kinase isoenzymes with endurance training reflect changes in the energy metabolism in the different muscle fibres, supporting the hypothesis that the different isoenzymes play different roles in energy transduction.     

Rapid activation of glycogen synthase and protein phosphatase in human skeletal muscle after isometric contraction requires an intact circulation

The effects of isometric contraction (66% of maximal force) and recovery on glycogen synthase fractional activity (GSF) in human skeletal muscle have been studied. Biopsies were taken from the quadriceps femoris muscle at rest, at fatigue and 5 min postexercise on two occasions: after one of the contractions, the circulation to the thigh was occluded during the 5 min recovery (OCC), and after the other contraction, the circulation was intact (control, CON). During CON, GSF decreased from (mean ± SE) 0.34±0.05 at rest to 0.24±0.02 at fatigue and then increased to 0.74±0.04 at 5 min postexercise; corresponding values for OCC were 0.37±0.04, 0.25±0.04 and 0.48±0.05 (P<0.001 vs. CON for 5 min postexercise only). Compared with the value at fatigue, protein phosphatase activity (PP) increased by 79±16% during CON recovery (P<0.01), whereas no change was observed during OCC recovery. Uridine diphosphate glucose increased by approximately 2.5-fold at fatigue, remained elevated during OCC recovery, but reverted to the preexercise level during CON recovery (P<0.001 vs. OCC recovery). Glucose 6-P increased approximately 5-fold at fatigue and was higher at 5 min postexercise in OCC vs. CON recovery (8.6±1.5 vs. 4.1±0.9 mmol/kg dry wt; P<0.01). It is concluded that the rapid increase in GSF after intense exercise with an intact circulation may be at least partly attributed to an increase in the specific activity of PP. The increase in GSF during recovery in OCC may be at least partly attributed to the high glucose 6-P content in vivo, which enhances the substrate suitability of GS for PP. Thus, separate mechanisms exist for the activation of PP and GS during recovery from intense short term exercise.     

Standardisation of 31phosphorus-nuclear magnetic resonance spectroscopy determinations of high energy phosphates in humans

A procedure is described for standardising the determination of adenosine 5-triphosphate and phosphocreatine concentration ([ATP] and [PC], respectively, in absolute arbitrary units) in human muscle by nuclear magnetic resonance (NMR) spectroscopy. The individual ³¹phosphorus (²¹P)-NMR spectra obtained on equal hemispherical tissue volumes (muscle plus skin and fat) were corrected for the thickness of the skin and of the subcutaneous fat. The volumes investigated were standardised using an external reference. The procedure described made possible the comparison of high energy phosphate concentrations among different subjects. It was applied to the assessment of [ATP] and [PC] in four groups of sedentary subjects (children, and adults aged 20–35, 35–50 and over 50 years), and in a group of athletes (volleyball players). The [ATP] and [PC] were not statistically different in the groups investigated.     

Muscle energetics in short-term training during hypoxia in elite combination skiers

Four well-trained combination skiers were studied through pre- and post-training for the effects of short-term intermittent training during hypoxia on muscle energetics during submaximal exercise as measured by Phosphorus-31 nuclear magnetic resonance and maximal aerobic power ( O_2max). The hypoxia and training in the cold was conducted in a hypobaric chamber and comprised 60-min aerobic exercise (at an intensity equivalent to the blood lactate threshold), using a cycle ergometer or a treadmill twice a day for 4, consecutive days at 5°C, in conditions equivalent to an altitude of 2000 m (593 mm Hg). No change in O_2max was observed over the training period, while in the muscle energetics during submaximal exercise, the values of phosphocreatine/(phosphocreatine + inorganic phosphate) and intracellular pH were found to be significantly increased by training during hypoxia. During recovery, the time constant of phosphocreatine was found to have been significantly reduced [pre, 27.9 (SD 6.7) s; post, 22.5 (SD 4.7) s, P < 0.01]. The observed inhibition of phosphocreatine as well as that of intracellular pH changes after training during hypoxia and quicker recovery of phosphocreatine in submaximal exercise tests, may indicate improved oxidative capacity (i.e. a high adenosine 5-triphosphate formation rate) despite the short-term hypoxia training. Present address: Department Life Sciences, Univ. of Tokyo, Komaba 3-8-1, Meguro-ku 153, Japan     

Effect of acute ammonia intoxication on energy stores in the cerebral reticular activating system

Summary Ammonia intoxication causes loss of consciousness. One postulated mechanism for this stipulates impaired energy metabolism in critical brain sites. The ascending reticular activating system in the brainstem may modulate consciousness. Accordingly, the present study, using micromethods, assessed energy stores in cells from the reticular activating system of mice acutely intoxicated with ammonia. In the early coma period (3.5 min after ammonia) phosphocreatine, adenosine triphosphate and glucose fell significantly while glycogen decreased later. Subsequently during coma, the high energy phosphates returned to normal and supranormal. The maximal fall in these metabolites was not accompanied by a rise in lactate, implying lack of local hypoxia or acidosis. The cells of the posterior colliculus in the same animals failed to show a significant fall in energy stores. These data suggest a selective effect of ammonia on energy metabolism in the cells of the reticular activating system of the brainstem.Abbreviations NH Ammonia - ATP Adenosine Triphosphate - PC Phosphocreatine - RAS Reticular Activating System Presented at the Annual Meeting of the American Association of the Study of the Liver Disease, Chicago, 1980Supported in part by USPHS Grant N.S. 16621     

磷酸肌酸对大鼠子宫缺血再灌注损伤的影响

目的：探讨外源性磷酸肌酸预处理对大鼠子宫缺血再灌注损伤的保护作用及其机制。方法选择 SD雌性大鼠45只,随机分为假手术组、缺血再灌注组和干预组,每组15只。干预组于缺血前30 min 经腹腔注射磷酸肌酸注射液10 mg/ kg,测定子宫组织中超氧化物歧化酶(SOD)活性和丙二醛(MDA)水平,并观察子宫病理组织学改变。结果与假手术组比较,缺血再灌注组和干预组大鼠子宫组织 SOD 活性明显降低,MDA 含量明显增加(P <0．05);与缺血再灌注组比较,干预组 SOD 活性升高,MDA 含量降低(P <0．05)。干预组病理组织学观察炎性反应较缺血再灌注组明显减轻。结论磷酸肌酸对大鼠子宫缺血再灌注损伤有保护作用,其机制可能与其增强 SOD 活性有关。     

磷酸肌酸钠治疗小儿原发性心肌炎的临床疗效分析

目的 分析原发性心肌炎（PMC）的特点,探讨磷酸肌酸钠治疗小儿PMC的临床疗效.方法 回顾性分析56例PMC患儿的临床资料,按随机数字表法分为对照组和治疗组,每组28例,两组患儿均接受常规治疗,治疗组在此基础上加用磷酸肌酸钠,两组均连续治疗14d,观察两组的临床疗效、心肌酶谱（肌酸激酶、肌酸激酶同工酶MB、乳酸脱氢酶）、肌钙蛋白及心电图改善情况.结果 治疗后,治疗组总有效率明显高于对照组[89.3％ （25/28）比53.6％（15/28）],差异有统计学意义（x2=4.094,P＜ 0.05）.两组患儿经治疗后,心肌酶谱均较治疗前明显改善,差异有统计学意义（P＜0.05）;且治疗组改善程度优于对照组,差异有统计学意义（P＜0.05）.治疗组治疗后肌钙蛋白转阴率明显高于对照组（16/18比9/17）,差异有统计学意义（x2=6.052,P＜ 0.05）.治疗组心电图改善的总有效率明显高于对照组[96.4％（27/28）比67.9％（19/28）],差异有统计学意义（x2=3.896,P＜0.05）.结论 磷酸肌酸钠用于治疗小儿PMC,临床疗效较好,心肌酶谱、肌钙蛋白等生理指标明显改善,具有一定的临床推广意义.     

磷酸肌酸钠对肝下下腔静脉联合门静脉阻断术围术期心肌酶的影响

目的 探讨磷酸肌酸钠对围术期心肌酶的影响.方法 选择择期采用肝下下腔静脉联合门静脉阻断行肝部分切除手术患者40例,随机均分为两组:Ⅰ组磷酸肌酸钠2.0 g在术前30 min开始输注,术后继续应用磷酸肌酸钠;Ⅱ组未用磷酸肌酸钠,给等剂量生理盐水.记录围术期HR、CVP以及MAP变化.于麻醉前、术后1、3、5 d和7 d抽血测定α-羟丁酸脱氢酶(α-HBD)、磷酸肌酸激酶(CK)、肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH)、谷丙转氨酶(ALT)和谷草转氨酶(AST).结果 与麻醉前比较,两组术后α-HBD浓度升高并持续到术后7 d(P＜0.05),术后1 d和3 d Ⅰ组增高的幅度比Ⅱ组小(P＜0.05).CK升高并持续到术后5 d(P＜0.05),Ⅰ组增高的幅度均比Ⅱ组小(P＜0.05).CK-MB和LDH分别于术后1 d和3 d升高(P＜0.05),但术后1 d Ⅰ组增高的幅度比Ⅱ组小(P<0.05).ALT升高并持续剑术后7 d,Ⅰ组增高幅度均比Ⅱ组小(P＜0.05).AST升高并持续到术后7 d(P＜0.05),术后1 d和3 d ＜组增高的幅度比Ⅱ组小(P<0.05).结论 围术期给予磷酸肌酸钠可以在一定程度上减轻肝下下腔静脉联合门静脉阻断所引起的心肌酶释放,对心肌损害有一定的保护作用.     

磷酸肌酸钠对活体肝移植术患者围术期心肌损伤的影响

目的 评价磷酸肌酸钠对活体肝移植术患者围术期心肌损伤的影响.方法 活体肝移植术患者40例,ASA分级Ⅱ～Ⅳ级,肝功能Child-Pugh分级B或C级,年龄45～62岁,体重47～91 kg,随机分为2组:对照组(C组)和磷酸肌酸钠组(CP组),每组20例.CP组切皮时静脉注射磷酸肌酸钠30 mg/kg,继以4 mg·kg-1·h-1的速率静脉输注至术毕;C组静脉输注等容量生理盐水.分别于切皮前即刻、无肝期5、30 min、新肝期5、30 min和术毕时,记录HR、MAP、CVP、肺动脉毛细血管楔压、CO和SvO2.于切皮前即刻、无肝期30 min、新肝期30 min、术毕、术后4和24 h时,采集中心静脉血样,测定血清心肌肌钙蛋白I(cTnI)、肌酸激酶同工酶(CK-MB)的浓度和乳酸脱氢酶(LDH)活性.记录术后不良事件的发生情况.结果 与切皮前即刻比较,两组新肝期30 min至术后24 h时血清cTnI、CK-MB的浓度和LDH活性升高(P＜0.05或0.01).与C组比较,CP组新肝期5 min至术毕时MAP和CO升高,新肝期30 min至术后24 h时血清cTnI、CK-MB的浓度和LDH活性降低,室性心律失常发生率降低(P＜0.05或0.01).结论 磷酸肌酸钠可减轻活体肝移植术患者围术期心肌损伤的程度.     

外源性磷酸肌酸对冠状动脉搭桥病人围术期免疫系统的影响

目的 观察用外源性磷酸肌酶（ＣＰ）对冠状动脉搭桥（ＣＡＢＧ）病人围术期补体及免疫球蛋白的变化,评价其对免疫系统的影响。方法 ２８例ＣＡＢＧ病人随机分为ＣＰ组１７例,对照组１１例,ＣＰ组于术前、后备用ＣＰ３～７ｄ,每天２ｇ静脉滴注,术中将ＣＰ加入心脏停搏液中,对照组椁前、中、后均不用ＣＰ。观察两组病人术前１周、麻醉诱导后、术中阻断升主动脉后５、３５、６５ｍｉｎ（１４例病人）、术毕、术后２４ｈ、术后１