血清Troponin I,CK-MBmass,Myoglobin在急性心肌梗塞诊断中的应用评价

为了解CTnI，CK－MBmass和Mb指标对急性心肌梗塞（AMI）早期诊断、后期监测及预后判断的临床意义，采用微粒子化学发光法，对20例AMI患者、24例不稳定心绞痛（UA）患者、17例骨骼肌损伤（SM）患者和19例健康者（对照组）进行血清CTnI，CK－MBmass和Mb的测定，并对AMI患者胸病发生3～5小时，8～14小时，20～24小时，72小时和7天共五个时段进行了测定。结果：AMI患者发病早期CTnI，CK－MBmass和Mb的阳性检出率分别为65％，70％，70％，CTnI在UA患者组和SM患者组中未检出。CTnI，CK－MBmass和Mb测定值含量在AMI组中明显高于UA组和SM组，AMI患者组CTnI分别是UA组和SM组的84倍和91.63倍，CK－Mbmass分别是该二组的8．82倍和4．67倍，Mb分别是该二组的11．57倍和2．25倍，AMI组与UA组和SM组比较，有显著性差异（P＜0．001）。AMI患者组中该三项指标的动态测定显示，在疾病发生早期（3～5小时）时，CTnI，CK－MBmass和Mb都有显著性升高，随时间延长而逐渐升高，高峰值期均在8～14小时段，72小时时Mb已基本回到正常。7天时血清中仍有CTnI的持续存在，但CK－MBmass已接近正常。以上显示，CTnI，CK－MBmass和Mb在早期诊断AMI时，都具有较高的敏感性，CTnI在AMI患者中的阳性检出率具有心肌特异性。

Third generation biosensor based on myoglobin-TiO_2/MWCNTs modified glassy carbon electrode

TiO2 nanoparticles were homogeneously coated on multi-walled carbon nanotubes by hydrothermal deposition, this nanocomposite may be a promising material for myoglobin immobilization in view of its high biocompatibility and large surface. The glassy carbon electrode modified with Mb-TiO2/MWCNTs films exhibited a pair of weU defined, stable and nearly reversible cycle voltammetric peaks. The electron transfer between Mb and electrode surface, Ks of 3.08 s^-1, was greatly facilitated in the TiO2/ MWCNTs film. The electrocatalytic reductions of hydrogen peroxide were studied, the apparent Michaelis-Menten constant is calculated to be 83.10 μmol/L, which shows a large catalytic activity of Mb in the TiO2/MWCNTs film to H2O2.

RIG-I,a novel DAMPs sensor for myoglobin,activates NF-κB/caspase-3 signaling in CS-AKI model

Background:Acute kidney injury(AKI)is the main life-threatening complication of crush syndrome(CS),and myoglobin is accepted as the main pathogenic factor.The pattern recognition receptor retinoicacid-inducible gene I(RIG-I)has been reported to exert anti-viral effects function in the innate immune response.However,it is not clear whether RIG-I plays a role in CS-AKI.The present research was carried out to explore the role of RIG-I in CS-AKI.Methods:Sprague-Dawley rats were randomly divided into two groups:the sham and CS groups(n=12).After administration of anesthesia,the double hind limbs of rats in the CS group were put under a pressure of 3 kg for 16 h to mimic crush conditions.The rats in both groups were denied access to food and water.Rats were sacrificed at 12 h or 36 h after pressure was relieved.The successful establishment of the CS-AKI model was confirmed by serum biochemical analysis and renal histological examination.In addition,RNA sequencing was performed on rat kidney tissue to identify molecular pathways involved in CS-AKI.Furthermore,NRK-52 E cells were treated with 200μmol/L ferrous myoglobin to mimic CS-AKI at the cellular level.The cells and cell supernatant samples were collected at 6 h or 24 h.Small interfering RNAs(siRNA)was used to knock down RIG-I expression.The relative expression levels of molecules involved in the RIG-I pathway in rat kidney or cells samples were measured by quantitative real-time PCR(qPCR),Western blotting analysis,and immunohistochemistry(IHC)staining.Tumor necrosis factor-α(TNF-α)was d etected by ELISA.Co-immunoprecipitation(Co-IP)assays were used to detect the interaction between RIG-I and myoglobin.Results:RNA sequencing of CS-AKI rat kidney tissue revealed that the different expression of RIG-I signaling pathway.qPCR,Western blotting,and IHC assays showed that RIG-I,nuclear factor kappa-B(NF-κB)P65,p-P65,and the a poptotic marker caspase-3 and cleaved caspase-3 were up-regulated in the CS group(P<0.05).However,the levels of interferon regulatory factor 3(IRF3),p-IRF3 and the antiviral factor interferon-beta(IFN-β)showed no significant c hanges between the sham and CS groups.Co-IP assays showed the interaction between RIG-I and myoglobin in the kidneys of the CS group.Depletion of RIG-I could alleviate the myoglobin induced expression of apoptosis-associated molecules via the NF-κB/caspase-3 axis.C onclusions:RIG-I is a novel damage-associated molecular patterns(DAMPs)sensor for myoglobin and participates in the NF-κB/caspase-3 signaling pathway in CS-AKI.In the development of CS-AKI,specific intervention in the RIG-I p athway might be a potential therapeutic strategy for CS-AKI.

Direct Electrochemistry of Myoglobin in DDAB-Clay Composite Films

Ordered films were made by casting a mixture of aqueous dispersions of didodecyldimethylammonium bromide (DDAB)-clay composite and myoglobin (Mb) solution on pyrolytic graphite (PG) electrodes. The Mb-DDAB-clay film electrodes showed stable and reversible cyclic voltammetric responses in buffers and can catalyze the reduction of id (TCA).

Myoglobin as Mimetic Enzyme and Its Analytical Application in Determination of H_2O_2

The characteristic of Myoglobin as mimetic enzyme was studied and applied in the determination of HeO2 with o-phenylenediamine as substrate. The absorbanee obtained at 40 ℃ was found to be proportional to the concentration of H2O2 in the range of 2.0×10^-5- 2.0×10^-7 mol/L, with a correlation coefficient of 0.999 1. The proposed meth od is simple and highly sensitive to a detection limit of 2.7 × 10^-8 mol/L. The relative standard deviations were within 5% for the determination of different concentrations of H2O2. Satisfied results were obtained in the determination of H2O2 in rainwater by this method, and the recoveries were at the range of 97.2%-105.4%.

Expression of Myoglobin in the Urine of Cocaine Users

Background: The possibility exists that cocaine use in the absence of frank clinical presentation of acute cardiac events may be associated with subclinical injury including the release of myoglobin which is a nonspecific marker for cardiac and skeletal muscle damage. Objectives: This investigation examined urine specimens for potential differences between cocaine use and the expression of myoglobin (a marker associated with cardiovascular damage, inflammation and oxidative stress). Methods:40 urine specimens were assayed for cocaine metabolites, creatinine, total protein (BSA) and myoglobin using ELISA and colorimetry. Results: We observed significant differences between male control and male cocaine positive urines for myoglobin. Interestingly, there was no statistically significant difference in females between control and cocaine positive urines. Conclusion: Differences in the urinary expression of myoglobin may be important in evaluating the gender based effects of cocaine use and may have potential clinical applications which may be related to gender differences in signs and symptoms of cocaine toxicity.

Availability of Myoglobin as a Molecular Marker for Phylogenetic Relationships of Fish

In order to elucidate the phylogenetic relationship of fish, DNA and deduced amino acid sequences of myoglobin （Mb） were used for the phylogenetic analyses based on different approaches, namely, maximum likelihood （ML）, neighbor joining （NJ）, unweighted pair group method with arithmetic means （UPGMA） and maximum parsimony （MP） methods in comparison with the conventional molecular markers, mitochondrial cytochrome b （cyt-b） and cytochrome c oxidase subunit I （COI）. The phylogenetic trees drawn based on Mb sequences were similar to those by the traditional classification based on the other molecular markers. The primary and secondary structures, as well as the modeled tertiary structures of Mbs were similar to each other, but were clearly distinguishable among those species. Such differences in structure would be associated with adaptation of Mb molecule to the physiological conditions of each species. These results suggest that Mb can be a molecular marker for the phylogenetic relationship of fish.

Allergenic risk assessment of porcine myoglobin expressed by engineered Komagataella Phaffii

Myoglobin produced by fermentation using engineered Komagataella phaffii is an important color additive in meat analogue products,but its allergenicity is poorly understood.Here,we initially searched the Allergen Online database and did not find any allergic or cross-reactive proteins in porcine myoglobin(PM).In vitro simulated digestion demonstrated that PM did not exhibit notable acid-base resistance or anti-digestion capabilities.However,sensitization was observed in BALB/c mice,including a significant increase in specific antibodies and biomarkers for allergic reactions,as well as alterations in gut microbiome and serum metabolome.Interestingly,the intensity of sensitization exhibited a negative correlation with the purity of PM.60%and 88%purities showed weaker sensitization compared to the ovalbumin control group.These allergic reactions were likely due to the non-myoglobin protein portion,highlighting the importance of purification processes and the urgent need to assess the allergenicity of this portion.

Unusual peroxidase activity of a myoglobin mutant with two distal histidines

By retaining the native distal His64 in sperm whale myoglobin （Mb）, a second distal histidine was engineered in Mb by mutating Leu29 to His29. The resultant mutant of L29H Mb exhibits an unusual enhanced peroxidase activity with a positive cooperativity in comparison to that of wild type Mb. The new enzyme with two cooperative distal histidines has not been found in native peroxidase, which emohasizes a creation of the rational nmt^in doclan

Investigation on the photo-induced de-oxygenation process of myoglobin in aqueous solution by use of fluorescence spectroscopy

A photo-induced de-oxygenation process of myoglobin (Mb) in aqueous solution was investigated by use of fluorescence spectroscopy. The spectra are characterized by the fluorescence intensity declining gradually after each scan,and the decay of fluorescence intensity being significant in each scan,which is assigned to the release of oxygen from the opening of the heme-pockets induced by illumination. More illumination will cause more release of oxygen; if the temperature of an Mb solution is increased when it is illuminated,the rate of de-oxygenation will be higher. It was found that ligand-oxygen in Fe-porphyrin could be removed from Mb by nitrogen. This indicates that the interac-tion between oxy-Mb and other different gases can be tested by the method of fluorescence spectros-copy. In addition,fluorescence spectroscopy can be employed to probe the energy transfer between Fe-porphyrin and tryptophan or tyrosine in Mb molecules.

Myoglobin/Gold Nanoparticles/Carbon Spheres 3-D Architecture for the Fabrication of a Novel Biosensor

A novel biosensor based on a myoglobin/gold nanoparticles/carbon spheres(Mb AuNPs CNs)3-D architecture bioconjunction has been fabricated for the determination of hydrogen peroxide(H2O2).Cyclic voltammetry(CV),Fourier transform infrared(FT-IR)spectroscopy and scanning electron microscopy(SEM)were used to characterize the bioconjunction of the AuNPs CNs with Mb.Experimental results demonstrate that the AuNPsCNs hybrid material is more effective in facilitating electron transfer of the immobilized enzyme than CNs alone,which can be attributed to the unique nanostructure and larger surface area of the bioconjunction.The biosensor displayed good performance for the detection of H_(2)O_(2)with a wide linear range from 0.28μmol/L to 116.5μmol/L and a detection limit of 0.12μmol/L.The Michaelis-Menten constant KMapp value was estimated to be 0.3 mmol/L.The resulting biosensor exhibited fast amperometric response,and good stability,reproducibility,and selectivity to H_(2)O_(2).

Myoglobin over-expression attenuates angiogenic response in hindlimb ischemia in mice

Background Myoglobin is expressed exclusively in striated skeletal muscles and has been implicated in nitric oxide scavenging. Accumulating data suggest a critical role for nitric oxide in both the endogenous and therapeutic angiogenic response to ischemia. A clear role for myoglobin in ischemic skeletal muscle is uncertain. We hypothesized that myoglobin overexpression has an adverse impact on the angiogenic response to ischemia. Methods Muscle-specific myoglobin over-expressing transgenic mice （MbTG, n=11）, wild type littermates （WT, n=23） underwent unilateral femoral artery ligation and excision. Laser doppler perfusion imaging was used to monitor changes in hindlimb perfusion before surgery and weekly after surgery up to 28 days. 13ssue ischemia was assessed by a necrosis incidence. Upon termination of the experiment （28 days after surgery）, skeletal muscles （gastrocnemius, and tibialis anterior） were harvested, the distal part of the muscle was frozen and embedded for histology study, the proximal part was used either to detect vascular endothelial growth factor （VEGF） level with enzyme-linked immunosorbent assays （ELISA） or to determine the proliferation （proliferating cell nuclear antigen （PCNA）） and apoptosis （Bax, and Bci-2） condition in ischemic muscle by Western blotting. Capillaries were stained with endothelial phosphate alkaline staining and vascular density was expressed in capillaries/fiber. Results The recovery of perfusion in MbTG mice was similar to that of WT mice on day 7 （0.485±0.095 vs 0.500±0.084） but was significantly less on day 14 （0.536±0.086 vs 0.623±0.077, P 〈0.05）, day 21 （0.588±0.082 vs 0.684±0.068, P 〈0.01） and day 28 （0.606±0.079 vs 0.733±0.093, P 〈0.01）. The necrosis incidence was higher in MbTG than in wr （54.5% vs 21.6%）. Vascular density was less in MbTG compared with that in WT （gastrocnemius 0.19±0.08 vs 0.30±0.08, P 〈0.05; tibialis anterior 0.22±0.11 vs 0.33±0.04, P 〈0.05）. With ischemic injury, the VEGF level was increased in both MbTG and wr （45.2% and 20.4%, respectively）. Western blotting showed that after hindlimb ischemia the proliferation was similar in both MbTG and WT, however, apoptosis was increased in MbTG relative to WT, shown as more expression of Bax and less expression of Bcl-2. Conclusion An increase in expression of myoglobin protein in skeletal muscle reduces the endogenous perfusion recovery following surgically induced hind-limb ischemia.

Direct electrochemistry and electrocatalysis of myoglobin in dodecyltrimethylammonium bromide film modified carbon ceramic electrode

Direct electrochemistry and electrocatalysis of myoglobin（Mb） were studied with Mb immobilized on dodecyltrimethylammonium bromide（DTAB） film modified carbon ceramic（CC） electrode.Cyclic voltammetry showed a pair of well-defined and nearly reversible redox peaks of Mb（Fe~Ⅱ/Fe~Ⅲ） at about—0.3 V vs.SCE（pH = 6.98）.The currents of the redox peak were linear to scan rate,and rate constant（Ks） was estimated to be 3.03 s^（-1）.The formal potential（E°＇） of Mb in the DTAB/CC electrodes shifted linearly with pH with a slope of -36.44 mV/pH,implying that the electron transfer between DTAB and CC electrodes is accompanied by proton transportation.The immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide（H2O2）.

FLOW INJECTION ANALYSIS OF MYOGLOBIN AND HEMOGLOBIN AT TOLUIDINE BLUE CHEMICALLY MODIFIED ELECTRODE

Hemoprotein molecules exhibit so slow electron transfer that no apparent currents appear at conventional electrodes because of either their extended three-dimensional structure and the reusltant inaccessibility to the electroactive centre or their strong adsorption onto the electrode surface for subsequent passivation. Chemically modified electrode (CME)made by adsporption of the phenothiazine methylene blue onto electrode was used for catalysis of hemoprotein electrode reactions in spectroelectrochemical study and in analysis of flow systems.

CHANGES OF MYOCARDIAL MYOGLOBIN, MYOSIN AND CREATINE KINASE IN CASES OF SUDDEN NOCTURNAL DEATH SYNDROME

Myoglobin, myosin creatine kinase MM (CK-MM),creatine kinase BB(CK-BB) in cardiac muscle and H chain ofmyosin in atrial and ventricular muscle were studied in speci-mens from 8 patients who died of sudden nocturnal deathsyndrome(SNDS) by avidin-biotin complex (ABC) method toinvestigate the possible early or very early myocardial ischemiain the syndrome. Hematoxylin-eosin staining was conductedfor comparison. The results showed evident loss of CK-MM,CK-BB, myoglobin and myosin from cardiac muscle cells, indi-caring that occurrence of SNDS is closely associated withacute myocardial ischemia.

Study on electrode process of myoglobin at a polymerized Toluidine Blue film electrode

This paper reports the use of an electrochemically polymerized Toluidine Blue (TB) film electrode.The film on platinum electrode surface was analyzed with ESCA.The heterogeneous electron transfer processes of myoglobin at the polymerized TB film electrode have been investigated using in situ UV-visible spectroelectrochemistry.The formal potential(E°′)and electron transfer number(n)of myoglobin were calculated as E°′=0.045 V(vs.NHE)and n=0.99.The exhaustive reduction and oxidation electrolyses are achieved in 130 s and 110 s respectively,during a potential step between-0.4 V and+0.4 V.A formal heterogeneous electron transfer rate constant(ksh)of 1.09× 10^(-4) cm/s and a transfer coefficient(α)of 0.47 were obtained by cyclic voltabsorptometry,which indicated that myoglobin underwent a quasi-reversible electrode process at the polymerized TB film electrode.

Serum procalcitonin levels are associated with rhabdomyolysis following exertional heatstroke: an over 10-year intensive care survey

BACKGROUND:Heatstroke has become a common emergency event in hospitals.Procalcitonin(PCT)is used as a biomarker of infection in the emergency department(ED),but its role in rhabdomyolysis(RM)following exertional heatstroke(EHS)remains unclear.METHODS:A retrospective cohort study enrolled patients with EHS from the intensive care unit(ICU).We collected RM biomarkers,inflammation markers,critical disease scores at admission,24 h,48 h,and discharge,and 90-day mortality.Correlation analysis,linear regression and curve fi tting were used to identify the relationship between PCT and RM.RESULTS:A total of 162 patients were recruited and divided into RM(n=56)and non-RM(n=106)groups.PCT was positively correlated with myoglobin(Mb),acute hepatic injury,disseminated intravascular coagulation(DIC),Sequential Organ Failure Assessment(SOFA)score,and Acute Physiology and Chronic Health Evaluation II(APACHE II)score,with correlation coefficients of 0.214,0.237,0.285,0.454,and 0.368,respectively(all P<0.05).Interestingly,the results of curve fi tting revealed a nonlinear relationship between PCT and RM,and a two-piecewise linear regression model showed that PCT was related to RM with an odds ratio of 1.3 and a cut-off of<4.6 ng/mL.Survival analysis revealed that RM was associated with higher mortality compared to non-RM cases(P=0.0093).CONCLUSION:High serum PCT concentrations are associated with RM after EHS in critically ill patients.Elevated PCT concentrations should be interpreted cautiously in patients with EHS in the ED.

老年舒张性心力衰竭合并肌少症患者可溶性生长刺激表达基因2蛋白、肌红蛋白、白细胞介素-6水平与心功能的相关性

目的 探讨老年舒张性心力衰竭(DHF)合并肌少症患者外周血可溶性生长刺激表达基因2蛋白(sST2)、肌红蛋白(Myo)、白细胞介素-6(IL-6)水平与心功能的相关性。方法 将122例DHF患者根据有无肌少症分为DHF合并肌少症组60例和DHF组62例,另将健康体检者58例、单纯肌少症患者60例分别纳入对照组、单纯肌少症组,检测各组外周血sST2、Myo、IL-6水平和心功能指标[左室射血分数(LVEF)、心排血量(CO)、心率(HR)、每搏输出量(SV)和心脏指数(CI)]。采用Pearson相关分析法分析sST2、Myo、IL-6与各心功能指标的相关性。绘制受试者工作特征(ROC)曲线,分析sST2、Myo、IL-6单独及联合诊断DHF合并肌少症的效能。结果 与对照组、单纯肌少症组相比,DHF组、DHF合并肌少症组sST2、Myo、IL-6水平和HR均升高,LVEF、CO、SV和CI均降低,差异有统计学意义(P<0.05);与DHF组相比,DHF合并肌少症组sST2、Myo、IL-6水平和HR均升高,LVEF、CO、SV和CI均降低,差异有统计学意义(P<0.05)。sST2、Myo、IL-6均分别与LVEF、CO、SV、CI呈负相关(P<0.001),均与HR呈正相关(P<0.001);sST2、Myo、IL-6、LVEF、SV是DHF合并肌少症的独立影响因素(P<0.05);sST2、Myo、IL-6联合诊断DHF合并肌少症的曲线下面积为0.936,诊断效能优于三者单独检测。结论 老年DHF合并肌少症患者外周血sST2、Myo、IL-6水平显著升高,且sST2、Myo、IL-6均与心功能指标显著相关,三者联合检测对DHF合并肌少症的诊断效能较高。

Exertional Rhabdomyolysis Induced Acute Kidney Injury: A Case Report and Literature Review

Background: The exRML (exertional rhabdomyolysis) is a pathophysiologic condition of skeletal muscle cell damage and breakdown associated with high intensity or prolonged exercise, normal exercise under extreme circumstances, or sudden and excessive skeletal muscle contraction. It may manifest from the increase in CK (creatine kinase) or MYO (myoglobin), a protein that can cause life-threatening injury to the kidney (AKI, acute kidney injury), and may or may not be associated with myoglobinuria. Here, we presented a case of exRML with AKI, and then reviewed the related reports. Vigorous hydration, sodium bicarbonate and furosemide are key treatments. Aim: To examine an elderly patient with exRML induced AKI and the key treatment process. Case summary: A 61-year-old man left our hospital without permission after his admission and has been walking for almost 30 kms with no water and food intake, then was diagnosed exRML and exRML induced AKI with an obvious elevation of CK, MYO and decrease of eGFR (estimated glomerular filtration rate) after coming back, and was treated with vigorous hydration, loop diuresis, sodium bicarbonate, prostaglandin and Shenkang injection. After vigorous resuscitation, the patient’s renal function, CK and MYO returned normal. Conclusions: The exRML can cause serious complications such as AKI and death. Delayed diagnosis can be critical;therefore, manner of time should be taken to achieve a favorable prognosis.

NT-proBNP、cTnI、Mb对风湿性心脏病患者人工瓣膜置换术预后情况的预测价值

目的:探讨N-末端脑钠肽前体(NT-proBNP)、心肌肌钙蛋白I(cTnI)、肌红蛋白(Mb)对风湿性心脏病(RHD)人工瓣膜置换术预后情况的预测价值。方法:选取2020年1月-2022年12月烟台市烟台山医院收治的RHD患者60例为研究对象,均接受人工瓣膜置换术治疗。比较预后良好组(n=47)、预后不良组(n=13)NT-proBNP、cTnI、Mb、左室射血分数(LVEF)水平,分析NT-proBNP、cTnI、Mb与LVEF的相关性,分析NT-proBNP、cTnI、Mb对RHD预后不良的预测效能。结果:预后不良组NT-proBNP、cTnI、Mb水平高于预后良好组,LVEF水平低于预后良好组,差异有统计学意义(P<0.05)。Pearson相关性分析结果显示,NT-proBNP、cTnI、Mb分别与LVEF呈负相关,差异有统计学意义(r=-0.685、-0.636、-0.614,P=0.016、0.022、0.027)。NT-proBNP、cTnI、Mb联合预测RHD预后不良的曲线下面积高于各单一指标,差异有统计学意义(P<0.05)。结论:NT-proBNP、cTnI、Mb与RHD预后情况相关,RHD患者血清NT-proBNP、cTnI、Mb含量升高,提示病情恶化风险增加,NT-proBNP、cTnI、Mb联合预测RHD预后有一定价值。