病毒性心肌炎患儿心肌损伤标志物检测分析

目的:探讨联合检测心肌损伤标志物对病毒性心肌炎(VMC)患儿心肌损伤的诊断价值.方法:对52例VMC、58例非病毒性心肌炎(NVMC)患儿和50例健康对照者,分别检测血清3种心肌损伤标志物[心肌肌钙蛋白Ⅰ(cTnⅠ)、肌酸激酶同工酶MB质量(CK-MB mass)、肌红蛋白(MYO)]浓度和4种心肌酶活性.结果:入院当日VMC组cTnⅠ(0.41±0.19)μg/L、CK-MB mass(6.02±3.89)μg/L、MYO(102.33±41.42)μg/L,均明显比NVMC组和对照组高(P<0.01);联合检测cTnⅠ、CK-MB mass和MYO对VMC心肌损伤的诊断灵敏度(SE)、特异性(SP)、阳性预报值(PPV)、阴性预报值(NPV)和准确度(AC)分别为71.15%、96.30%、90.24%、87.39%和88.13%:SE和NPV与联合检测4种心肌酶相近(P>0.05),而SP、PPV和AC却明显比联合检测4种心肌酶高(P<0.01).结论:联合并动态检测3种心肌损伤标志物比联合检测4种心肌酶能够为VMC心肌损伤的诊断、治疗和预后转归判断提供更好的诊断方法.     

Myoglobin‐Induced Apoptosis: Two Pathways Related to Endoplasmic Reticulum Stress

Myoglobin plays an important role in rhabdomyolysis‐induced acute kidney injury (AKI), but the underlying mechanisms are still unclear. The present study investigates myoglobin‐induced apoptosis in HK‐2 cells (human renal proximal tubule cells) to discover some of the mechanisms involved in rhabdomyolysis related AKI. Metmyoglobin is reduced to ferrous myoglobin by ascorbic acid, and then the HK‐2 cells are incubated with ferrous myoglobin. Cell viability is measured by 3‐(4,5)‐dimethylthiahiazo(‐z‐y1)‐3,5‐di‐phenytetrazoliumromide (MTT) assay, and cell injury is tested by supernatant lactose dehydrogenase (LDH). Cell apoptosis is evaluated by fluorescent microscopy of Hoechst staining and by flow cytometry of Annexin V/PI double staining. The apoptosis related protein expression is determined by Western blot. HK‐2 cells were incubated with 200 µM ferrous myoglobin for 24 h, the cell viability decreased and supernatant LDH release increased. Hoechst staining indicated more apoptosis after incubation. Molecular chaperone glucose‐related protein 78 (GRP78), cytochrome C, caspase‐9 started to increase within 3 h after incubation while caspase‐4, caspase‐8 showed no significant change. (iii) When the inositol triphosphate receptor (IP3R) calcium channel was blocked by 2‐aminoethoxydiphenyl‐borinate (2‐APB), caspase‐9 was completely inhibited, GRP78 and caspase‐4 increased dramatically, and caspase‐3 expression was not affected. The apoptosis in HK‐2 cells showed no significant change. Apoptosis in HK‐2 cells incubated with ferrous myoglobin is an endoplasmic reticulum stress induced, IP3R calcium channel mediated, caspase‐9 dependent intrinsic pathway. When the intrinsic pathway was inhibited using an IP3R calcium channel blocker, endoplasmic reticulum stress increased, resulting in the activation of caspase‐4 that cleaved caspase‐3 and generated a substitutive pathway of apoptosis.     

新兵军事训练中骨骼肌细胞损伤的研究

目的调查军事训练中骨骼肌肉损伤情况。方法应用肌酸激酶（creatine kinase,CK）和肌红蛋白（myoglobin,Mb）评估肌肉损伤,对563名新兵进行了血清电解质、CK、肌酸激酶同功酶（creatine kinase isoenzyme-MB,CKMB）、Mb和肌钙蛋白Ⅰ（cardiac troponinⅠ,cTnⅠ）检测。结果军事训练后CK和Mb明显升高,而cTnⅠ均正常。高CK值者血清钾、钠和镁含量低,而血清磷含量高。且体质量指数与血清CK含量呈正相关。结论军事训练可引起骨骼肌细胞损伤,低钾、低镁和超重是军事训练引起骨骼肌细胞损伤的高危因素。     

Relationship between myoglobin contents and increases in cyclic GMP produced by glyceryl trinitrate and nitric oxide in rabbit aorta,right atrium and papillary muscle

Summary Effects of glyceryl trinitrate (GTN) and nitric oxide (NO) on the cardiac functions and myocardial cyclic GMP (cGMP) contents were examined in comparison with those in the aorta and correlated with myoglobin (an inhibitor of soluble guanylate cyclase) contents using the preparations isolated from the reserpinized rabbit.GTN (10^–10-10^–4mol/l) produced a dose-dependent relaxation in the aorta. However, this compound exerted no effect on the rate of the spontaneous beat of the right atrium and the contraction of the papillary muscle. A transient and significant increase in cGMP was observed in the aorta with GTN (3 × 10^–6 mol/l). Although the increase was also observed in the right atrium, it was much smaller. No definite change was observed in papillary muscle. Increases in cGMP produced by NO (3 × 10^–6 mol/l) were larger and significant in all tissues; (AUC_cGMP(GTN)/AUC_cGMP(NO)) ratio was 30.1 for the aorta, 65.0 for the right atrium and 16.3% for the papillary muscle. Although higher concentrations of NO were necessary in the right atrium and papillary muscle to induce increases in cGMP, no differences were noted in the three tissues as regards the maximum accumulation of this substance. Furthermore, kinetic analysis of NO-induced increases in tissue cGMP indicated no marked difference in the production rate among the three tissues, while the rate of elimination of cGMP was lower in the aorta than in the atrium or the papillary muscle. The increases in cGMP observed in these three tissues were inversely related to the contents of myoglobin in respective tissues. No effect on myocardial function was observed with NO up to the concentration of 3 × 10^–5 mol/l.These results suggest that myoglobin, an endogenous inhibitor of activation of soluble guanylate cyclase by NO, was responsible for the lower production of cGMP by NO and GTN in the myocardial tissue. Correspondence to T. Ishibashi at the above address     

Oxygen transport and the function of myoglobin

We studied the steady-state oxygen transfer across thin layers of respiring chicken gizzard smooth muscle and compared three models for oxygen consumption with respect to their influence on the facilitation of oxygen diffusion by myoglobin. These models assumed zero-order, Michaelis-Menten or exponential kinetics. The transport equation was solved for these models with simultaneous oxygen facilitation assuming chemical equilibrium between oxygen and myoglobin. Experimental flux data were obtained in two situations: a) high oxygen pressure throughout the layer of tissue providing maximum oxygen consumption and oxygen permeability, and b) anoxic conditions in part of the layer and with submaximal oxygen consumption and desaturation of myoglobin. Measurements in the presence of functional myoglobin were compared with data obtained after abolishing the transport function of myoglobin by application of 1kPa carbon monoxide. It was found that oxygen consumption interferes with the facilitation effect. The oxygen pressure at half maximum oxygen consumption in the Michaelis-Menten model was 0.3±0.1 (S.E.) kPa. The facilitation of the oxygen transport by myoglobin was 50 to 100% of the maximum value to be expected on the basis of the prevailing myoglobin concentration.     

The significance of simultaneous estimation of serum creatine kinase and myoglobin in neuromuscular diseases

Summary Serum creatine kinase (CK) and myoglobin (Mb) levels were measured in patients with different neuromuscular diseases, carriers of X-linked Duchenne-type muscular dystrophy and normal volunteers. The highest levels were found in Duchenne dystrophy and both values decreased in parallel with age. In patients suffering from limb-girdle dystrophy the increases in CK activity and Mb concentration were also pronounced. However, there were families with normal and others with elevated CK and Mb levels in facioscapulohumeral dystrophy. In neurogenic atrophies both CK and Mb levels generally increased only slightly. Serum Mb and CK levels have similar values as indicators of muscle damage in primary and secondary skeletal muscle disorders. The serum Mb level helps in the detection of carriers but is not more sensitive than CK measurement.     

Photometrische Messungen am schlagenden Herz von Myxine glutinosa L. zur Erfassung intracellulär gelegener Hämoproteine

Zusammenfassung 1. Spektralphotometrische Untersuchungen am Herzen des primitiven Hexenfisches Myxine glutinosa L. ergaben folgendes: In der Herzmuskulatur von Myxine existiert ein dem Hämoglobin sehr ähnliches Hämoproteid, dessen -Bande (578.3 nm) gegenüber der des Hämoglobins (577,0 nm) um durchschnittlich 1,3 nm zu längeren Wellenlängen verschoben ist.Die Cytochrome a/a₃ (603–609 nm), c (548,9 nm) und b (562,5 nm) sind in der Herzmuskulatur nachzuweisen.2. Es wurde eine Perfusionsanordnung entwickelt, die die photometrische Messung am isolierten, spontan schlagenden, blutfrei perfundierten Herzen von Myxine ermöglicht.3. Es wurde eine Methode der Filterpapierphotometrie entwickelt, die auf einfache Weise die Messung geringer Flüssigkeitsmengen (z. B. Blut) gestattet und mit der Cuvettenmethode identische Werte liefert.Mit Unterstützung der Deutschen Forschungsgemeinschaft und des Schwedischen Naturwissenschaftlichen Forschungsrates.     

Erhöhtes Serum-Myoglobin bei Niereninsuffizienz

Zusammenfassung Bei 44 Patienten mit chronischer Niereninsuffizienz unterschiedlicher Äthiologie wurde das immunreaktive Serum-Myoglobin bestimmt und mit den Werten von Probanden mit normaler Nierenfunktion verglichen. Es fand sich — unabhängig von der Grunderkrankung — eine hoch signifikante lineare Korrelation zwischen dem Serum-Myoglobin und der Serum-Kreatinin-Konzentration. Bei Patienten mit Serum-Kreatinin-Werten über 550 µMol/1 (6,2 mg-%) lagen die Serum-Myoglobin Konzentrationen fast regelmäßig im pathologischen Bereich. Dies gilt auch für chronische Dialysepatienten. Die Befunde zeigen, daß bei Patienten mit höhergradiger, chronischer Niereninsuffizienz das Serum-Myoglobin nur mit Einschränkung zur Infarktdiagnostik geeignet ist.Mit Unterstützung des SFB-89 Kardiologie der Deutschen Forschungsgemeinschaft     

The optimised CO-rebreathing method: a new tool to determine total haemoglobin mass routinely

A routine method to determine total haemoglobin mass (tHb) in clinical practice and sports medicine is non-existent. Radioactive tracers or other dilution procedures like the common CO-rebreathing method (Proc_com) are impractical, the latter in particular because of the relatively long time of respiration. According to the multicompartment model of Bruce and Bruce (J Appl Physiol 95:1235–1247, 2003) the respiration time can be considerably reduced by inhaling a CO-bolus instead of the commonly used gas mixture. The aim of this study was to evaluate this theoretical concept in practice. The kinetics of the HbCO formation were compared in arterialised blood sampled from an hyperaemic earlobe after inhaling a CO-bolus (Proc_new) for 2 min and a CO–O₂ mixture (Proc_com) for ∼10 min. The reliability of Proc_new was checked in three consecutive tests, and phlebotomy was used to determine the validity. VO_2max was determined with and without previous application of Proc_new and the half-time of HbCO was registered also in arterialised blood after resting quietly and after the VO_2max test. Proc_new yielded virtual identical tHb values compared to Proc_com when HbCO determined 5 min after starting CO-rebreathing was used for calculation. The typical error of Proc_new was 1.7%, corresponding to a limit of agreement (95%) of 3.3%. The loss of 95 g (19) haemoglobin was detected with an accuracy of 9 g (12). After application of Proc_new VO_2max was reduced by 3.0% (3.7) (P=0.022) and half-time was lowered from 132 min (77) to 89 min (23) after the VO_2max test. Inhaling a CO-bolus markedly simplifies the CO-rebreathing method without reducing validity and reliability and can be used for routine determination of tHb for various indications.     

Responses of old men to repeated bouts of eccentric exercise of the elbow flexors in comparison with young men

A bout of eccentric exercise confers protection against subsequent bouts of the same exercise. This study investigated whether the protective effect would be produced similarly between old and young adults. Eight old men (70.5 ± 4.1 years) and ten young men (20.4 ± 2.0 years) performed two bouts of eccentric exercise of the elbow flexors (six sets of five eccentric actions) separated by 4 weeks. Changes in maximal isometric strength, range of motion (ROM), upper arm circumference (CIR), plasma creatine kinase (CK) activity, myoglobin (Mb) concentration, and muscle soreness (SOR) before, immediately after, and 1, 24, 48, 72 and 96 h following exercise were compared between bouts, and between groups by a two-way repeated measures ANOVA. Changes in the measures following the first bout were significantly (P < 0.05) smaller for the old than the young group. The young group showed significantly (P < 0.05) smaller changes in all measures following the second bout than the first bout; however, the old group had the protective effect only for ROM, Mb, and SOR. The magnitude of the effect observed for ROM and Mb concentration in the old group was significantly (P < 0.05) smaller compared with that of the young group. These results suggest that the protective effect conferred by the first bout was less for the old than the young group. This may be due to the less muscle damage after the first bout in the old subjects, but it is also possible that the protective effect of old adults does not last as long as that of young adults.