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PubMed1977

Antibodies against protein antigenic sites that are identical in the homologous protein of the immunized animal. Autoreactivity in rabbits of antibodies to sperm-whale myoglobin.

Sequence comparisons between the antigenic sites of sperm-whale myoglobin and the corresponding regions in rabbit myoglobin indicate that rabbits make antibodies to regions of the sperm-whale myoglobin molecule which are identical to the corresponding regions in rabbit myoglobin. Rabbit myoglobin did not precipitate with antisera to sperm-whale myoglobin. However, it exhibited an extensive cross-reaction as demonstrated by its ability to inhibit the precipitin reaction of sperm-whale myoglobin, and on an immunoadsorbent, bound a large amount of antibodies to sperm-whale myoglobin.

Amino Acid Sequence↗
PubMed1983

Identification and properties of myocardial myoglobin as a binder of iodothyronines.

Gel filtration of dog myocardial cytosol previously incubated with [125I]T4 or [125I]T3 revealed hormone binding in three fractions, one of which, M-2, was presumptively identified as myoglobin by absorbance maximum, molecular weight and specific immunodiffusion. Gel chromatography of purified horse or dog myoglobins incubated with labeled T3 or T4 resulted in coelution of the myoglobin and iodothyronine peaks. Excess unlabeled thyroid hormone displaced no more than 25% of tracer bound to myoglobin. Acid-acetone fractionation of myoglobin into heme and globin, and subsequent precipitation of the heme, localized hormone binding to the heme moiety. Hematin (ferric state heme) in solution was also shown to bind thyroid hormone. Added to human sera which were then subjected to T3 or T4 radioimmunoassay, myoglobin reduced detectable, endogenous iodothyronine by 77 and 26%, respectively. The myoglobin effect was concentration dependent. Heart myoglobin, like hemoglobin in the erythrocyte, is a cytoplasmic heme protein responsible for a major fraction of binding of intracellular iodothyronine. The nature of the interaction between iodothyronines and the heme prosthetic group is unclear.

Animals↗
PubMed1981

Serum myoglobin in muscular dystrophy and carrier detection.

Serum myoglobin was measured by radioimmunoassay in 143 patients with various muscle diseases including 55 boys with Duchenne dystrophy, 56 carriers of the Duchenne dystrophy gene, 8 carriers of the Becker dystrophy gene, 60 first-degree relatives of patients with sporadic (non-genetically transmitted) muscle diseases and 85 normal controls. A significant difference (P less than 0.001) was found between the serum myoglobin levels in normal control men (x = 31.7 range 10-70 microgram/l) and those in women (x = 17.2 range 4-27 microgram/l) but no difference was found between the controls and relatives of patients with muscle disease. Up to the age of 60 years, no correlation was found between age and serum myoglobin levels in controls. However, levels in boys with Duchenne dystrophy were found to increase slightly up to the age of 10 years and to decrease thereafter. No correlation was found between serum myoglobin and creatine kinase activity in these boys but in Duchenne carriers correlation was close (P less than 0.001). Eighteen of 23 definite and 13 of 33 possible carriers of Duchenne dystrophy had myoglobin concentrations above the equivalent normal range. Of those carriers with elevated myoglobin levels, 7 definite and 4 possible carriers had normal serum creatine kinase activity. This was equivalent to an improvement in "detection" of 31% and 12% in these groups of carriers. Of the 8 Becker dystrophy carriers, 6 had elevated myoglobin but all had normal creatine kinase levels. It appears that measurement of serum myoglobin as well as creatine kinase activity may be of great benefit to carrier detection programmers, but the need to establish accurately the extent of normal variation in women is emphasized.

Adolescent↗
PubMed1996

Conversion of metmyoglobin to NO myoglobin in the presence of nitrite and reductants.

Formation of NO myoglobin through the reaction of horse heart metmyoglobin with NADH in the presence of nitrite was observed optically at pH 5.5. Superoxide generation during the reaction was demonstrated using the ESR spin trap, 5,5-dimethyl-1-pyrroline-1-oxide. A weak optical spectrum corresponding to oxymyoglobin appeared transiently and the spectrum of NO myoglobin then developed. The conversion to NO myoglobin was eliminated in the presence of catalase, SOD or 5,5-dimethyl-1-pyrroline-1-oxide. The kinetics of NADH oxidation and oxygen consumption catalyzed by myoglobin showed an initial lag phase, indicating a chain reaction. When the oxygen was exhausted, the NO form emerged. The duration of the lag phase was prolonged by an increase in the concentration of catalase, SOD or 5,5-dimethyl-1-pyrroline-1-oxide, whereas it disappeared in the presence of H2O2. The spectral change from metmyoglobin to NO myoglobin was also observed under anaerobic conditions though the rate was slower than that obtained under aerobic conditions, while the spectral change was accelerated in the presence of H2O2. Nitric oxide (NO) was derived through the reaction of nitrite with NADH. The formation of NO myoglobin from metmyoglobin is explained in terms of the NADH-oxidase reaction catalyzed by myoglobin. Ascorbate and GSH also serve as reductants though NO myoglobin was formed slowly.

Animals↗
PubMed2004

Delta creatine kinase-MB outperforms myoglobin at two hours during the emergency department identification and exclusion of troponin positive non-ST-segment elevation acute coronary syndromes.

STUDY OBJECTIVE: Limited information is available about the diagnostic performance of creatine kinase (CK)-MB and myoglobin levels during the early evaluation of chest pain patients using cardiac troponins as the criterion standard for diagnosing acute myocardial infarction. In this study, we compare the sensitivity and specificity of the baseline, 2-hour absolute, and 2-hour delta values of myoglobin and CK-MB mass assay for detection of acute myocardial infarction using cardiac troponin I (troponin) as the sole marker of myocardial necrosis. METHODS: A prospective observational study was conducted of 975 chest pain patients with a baseline troponin level of 1.0 ng/mL or less (Abbott Axsym Assay) and an initial ECG nondiagnostic for injury. CK-MB, myoglobin, and troponin levels were all measured on the Abbott Axsym immunoassay. Acute myocardial infarction was diagnosed if there was at least 20 minutes of chest pain and any one of the following criteria within 24 hours of ED presentation: a serial increase in troponin to more than 1.0 ng/mL, new Q-wave formation in 2 contiguous leads, or patient death by cardiac or unknown cause. The optimal values of CK-MB and myoglobin were chosen at the most accurate value on the receiver operating characteristic (ROC) curve (ie, value with lowest false-negative and false-positive rate) of the 2-hour absolute and 2-hour delta value for predicting acute myocardial infarction. RESULTS: Acute myocardial infarction was diagnosed in 44 (4.5%) of the 975 study patients. ROC curve analysis revealed no statistically significant differences in areas for myoglobin and CK-MB values at baseline and 2 hours for determination of acute myocardial infarction. However, the ROC curve area of the delta CK-MB level significantly outperformed the ROC curve area of the delta myoglobin level for early identification of acute myocardial infarction (0.97 versus 0.81; 95% confidence interval [CI] for difference between areas 0.09 to 0.24). At the most accurate cutoff value, a 2-hour delta CK-MB level more than 0.7 ng/mL had a sensitivity of 93.2% (95% CI 81.3% to 98.5%), a specificity of 94.4% (95% CI 92.7% to 95.8%), a positive likelihood ratio of 16.7, and a negative likelihood ratio of 0.07. CONCLUSION: A 2-hour delta CK-MB level outperforms myoglobin level in the early identification and exclusion of acute myocardial infarction in non-ST-segment elevation chest pain patients. This finding suggests that myoglobin may no longer be the optimal early marker of acute myocardial infarction when troponins are used as the criterion standard.

Angina, Unstable↗
PubMed2007

Optimizing the formulation of a myoglobin molecularly imprinted thin-film polymer--formed using a micro-contact imprinting method.

Thin-film myoglobin molecularly imprinted polymers have been fabricated using a micro-contact approach. By initially selecting the cross-linker on the basis of it having a minimal recognition for the template and using this as a starting point for functional monomer selection, we have produced myoglobin imprinted polymers with exceptionally high selectivities. The affinity of the polymers, for myoglobin, when prepared with a variety of different cross-linkers and no functional monomer was evaluated. Of these, tetraethylene glycol dimethacrylate (TEGDMA) exhibited the lowest affinity for the template species. Methyl methacrylate (MMA) was chosen as the functional monomer as when it was used in conjunction with TEGDMA, it exhibited maximum selectivity for the template compared to polymers made with other functional monomers. With a MMA to TEGDMA ratio of 1 to 3, the myoglobin molecularly imprinted polymer adsorbed 15.03+/-0.89 x 10(-11)mole/cm(2) of template from a 5.68 x 10(-7)M myoglobin solution, compared to 2.58+/-0.02 x 10(-11)mole/cm(2) for a polymer of similar composition, but formed in the absence of a template. Various washing conditions, using alkaline media to remove the template, were investigated. An extraction solvent comprising 2 wt.% SDS and 0.6 wt.% NaOH used at 80 degrees C for 30 min was shown to give the highest imprinting factor i.e. 5.83 with 72.82% myoglobin removal. The saturation kinetics of template binding to the thin-film MIP were examined and found to display a simple two-phase profile typical of non-cooperative binding. A Scatchard binding plot showed the dissociation constant (K(d)) for the specific binding phase to be 3.4 x 10(-7)M and the binding site capacity to be 7.24 x 10(-11)mole/cm(2). For the non-specific binding phase, K(d) was found to be 1.355 x 10(-5)M and the binding site capacity was determined as 9.62 x 10(-10)mole/cm(2). Selectivity experiments were carried out in both single protein and binary protein systems all using a total protein concentration of 5.68 x 10(-7)M. The molar ratio of adsorbed myoglobin to IgG, HSA and hemoglobin was found to 115.5, 230.9 and 2.5, respectively. While, in binary competition systems, myoglobin selectivity to IgG, HSA and hemoglobin was, respectively, 94.18, 98.21 and 61.09%. Rebinding in natural biological matrices, i.e. human serum or urine, showed the imprinted films to have significantly greater uptake than non-imprinted films. Re-binding in undiluted urine was found to be a facile process, with the imprinting factor, i.e. the ratio of MIP to NIP binding, being determined as 37.4.

Cross-Linking Reagents↗
PubMed1993

Structure-dynamics-function relationships in Asian elephant (Elephas maximus) myoglobin. An optical spectroscopy and flash photolysis study on functionally important motions.

In this work we report the thermal behavior (10-300 K) of the Soret band lineshape of deoxy and carbonmonoxy derivatives of Asian elephant (Elephas maximus) and horse myoglobins together with their carbon monoxide recombination kinetics after flash photolysis; the results are compared to analogous data relative to sperm whale myoglobin. The Soret band profile is modeled as a Voigt function that accounts for the coupling with high and low frequency vibrational modes, while inhomogeneous broadening is taken into account with suitable distributions of purely electronic transition frequencies. This analysis makes it possible to isolate the various contributions to the overall lineshape that; in turn, give information on structural and dynamic properties of the systems studied. The optical spectroscopy data point out sizable differences between elephant myoglobin on one hand and horse and sperm whale myoglobins on the other. These differences, more pronounced in deoxy derivatives, involve both the structure and dynamics of the heme pocket; in particular, elephant myoglobin appears to be characterized by larger anharmonic contributions to soft modes than the other two proteins. Flash photolysis data are analyzed as sums of kinetic processes with temperature-dependent fractional amplitudes, characterized by discrete pre-exponentials and either discrete or distributed activation enthalpies. In the whole temperature range investigated the behavior of elephant myoglobin appears to be more complex than that of horse and sperm whale myoglobins, which is in agreement with the increased anharmonic contributions to soft modes found in the former protein. Thus, to satisfactorily fit the time courses for CO recombination to elephant myoglobin five distinct processes are needed, only one of which is populated over the whole temperature range investigated. The remarkable convergence and complementarity between optical spectroscopy and flash photolysis data confirms the utility of combining these two experimental techniques in order to gain new and deeper insights into the functional relevance of protein fluctuations.

Animals↗
PubMed2003

Myoglobin gene expression attenuates hepatic ischemia reperfusion injury.

BACKGROUND: Cellular functions are maintained by a continuous supply of ATP, which is supplied efficiently by mitochondrial oxidative phosphorylation. Since myoglobin, found in cardiac myocytes and red skeletal muscle, but not in the liver, facilitates oxygen diffusion under low oxygen conditions and enhances oxidative phosphorylation, this study seeks to enhance hepatic ATP levels and attenuate ischemia-reperfusion injury in rodent livers by adenovirus-mediated myoglobin expression. MATERIAL AND METHODS: After infecting Hep3B and rodent livers with adenovirus carrying CMV promoter sequences linked to the human myoglobin gene (AdCMVMyo), reverse transcriptase-PCR and immunodetection for myoglobin, and cellular and hepatic ATP levels were examined. The effect of myoglobin was evaluated in a hepatic ischemia-reperfusion model in the rat. RESULTS: Myoglobin expression was confirmed in Hep3B and rat livers after AdCMVMyo infection. The ATP levels in Hep3B cells and C57BL/6 mice livers 72 h after AdCMVMyo transfection were significantly higher than control levels and those after adenovirus-mediated beta-galactosidase transfection. Finally, expression of myoglobin attenuated ischemia-reperfusion injury in the rat liver. CONCLUSION: These results indicate that myoglobin gene transfer to the liver enhanced ATP levels both in vitro and in vivo and might be a novel strategy to reduce ischemia-reperfusion injury.

Adenosine Triphosphate↗
PubMed1997

A myoglobin variant with a polar substitution in a conserved hydrophobic cluster in the heme binding pocket.

Well-ordered internal amino acids can contribute significantly to the stability of proteins. To investigate the importance of the hydrophobic packing interface between helices G and H in the proximal heme pocket of horse heart myoglobin, the highly conserved amino acid, Leu104, was substituted with asparagine, a polar amino acid of similar size. The Leu104Asn mutant protein and its recombinant wild-type horse heart myoglobin counterpart were expressed from synthetic genes in Escherichia coli. Thermal denaturation of these two recombinant myoglobins, as studied by measurement of circular dichroism ellipticity at 222 nm, revealed that the Leu104Asn mutant had a significantly lower t(m) (71.8 +/- 1 degree C, pH 7.0) than recombinant wild-type myoglobin (81.3 +/- 1 degree C, pH 7.0). To examine the extent to which this 10 degrees C decrease in thermal stability was associated with structural perturbations, X-ray diffraction techniques were used to determine the three-dimensional structures of both the recombinant wild-type and Leu104Asn myoglobins to 0.17 nm resolution. Refinement of these structures gave final crystallographic R-factors of 16.0% and 17.9%, respectively. Structural comparison of the natural and recombinant wild-type myoglobins, together with absorption spectroscopic and electron paramagnetic resonance (EPR) analyses, confirmed the proper expression and folding of the recombinant protein in E. coli. Surprisingly, despite the decreased thermal stability of the Leu104Asn mutant, there are no significant structural differences between the mutant and wild-type myoglobins. EPR and absorption spectroscopic analyses further confirmed the similar nature of the heme iron centres in both proteins. Thus, the introduction of an energetically unfavourable change in side chain polarity at position 104 into a hydrophobic environment that does not support the hydrogen bonding potential of the mutant asparagine appears to perturb important stabilizing helix-helix and heme-protein interactions. The induced structural destabilization is thereby reflected by a significant decrease in the t(m) of horse heart myoglobin.

Animals↗
PubMed1997

Kinetic characterization of myoglobins from vertebrates with vastly different body temperatures.

Fish myoglobins are structurally distinct from the previously characterized mammalian myoglobins. Teleost fishes express generally lower levels of myoglobin than those found in mammals. Although the oxygen binding affinity is essentially the same as mammalian myoglobins, oxygen dissociation rates and carbon monoxide combination rates of the teleost myoglobins studied are significantly faster. Thus, the kinetic parameters of myoglobin from two Antarctic teleost species, measured close to their body temperature of -1 degree C, are comparable to those of mammalian myoglobins with higher body temperatures. These data suggest myoglobins from Antarctic teleosts may function at extreme environmental temperatures.

Animals↗
PubMed2003

Comparison of the sequences of Turbo and Sulculus indoleamine dioxygenase-like myoglobin genes.

Some archaeogastropodic molluscs, including Sulculus and Turbo, contain an unusual approximately 40 kDa myoglobin in their buccal masses. This myoglobin can bind oxygen reversibly, but has a lower oxygen affinity than vertebrate and invertebrate myoglobins. Amino acid sequences clearly show that Sulculus and Turbo myoglobins evolved not from the globin gene but from the gene for indoleamine dioxygenase (IDO), a tryptophan-degrading enzyme. The Turbo myoglobin gene has been determined to consist of 14 exons and 13 introns. Compared with the known Sulculus IDO-like myoglobin gene, all splice junctions except two are conserved exactly between the two genes. The exon/intron organization of these myoglobin genes is also highly homologous with human IDO (ten exon/nine intron structure); splice junctions of six introns were exactly conserved among the three genes, suggesting that these introns have been conserved for at least 600 million years. To look for putative IDO genes in Turbo or Sulculus, we re-examined the genomic DNA fragments amplified by PCR in full detail, and found intron 2 in two distinct Sulculus fragments (A and B). Fragment A with a 576 bp intron corresponded exactly to the myoglobin gene of Sulculus. On the other hand, fragment B, containing a 239 bp intron, differed significantly from fragment A in nucleotide and translated amino acid sequences. Detailed sequence comparison suggests that fragment B may be derived from a putative IDO gene of Sulculus.

Amino Acid Sequence↗
PubMed1999

The effect of lethal electrical shock on postmortem serum myoglobin concentrations.

Postmortem serum myoglobin concentrations in blood from the femoral vein (peripheral withdrawal) and the heart (central withdrawal) of nine electrical fatalities were compared with those of 74 individuals who had died of other causes. Independent of the cause of death or topographical site, serum myoglobin concentrations rose dramatically with the passage of postmortem time (maximum concentrations in the control group: 975,100 micrograms/l). In 59% of the total sample (electrical fatalities plus controls), serum myoglobin concentrations were higher in the central blood, in the other 41% the concentrations were higher in the peripheral blood. The differences in concentrations between the peripheral and the central withdrawal area correlated with neither the postmortem interval nor the cause of death. Up to the second day postmortem there was a statistically significant difference in serum myoglobin concentrations between electrical fatalities and controls. The individual values within each group, however, varied widely and overlapped between groups. Controls who had also suffered muscle injury (polytrauma, myocardial infarction) did not have significantly higher serum myoglobin concentrations than controls without muscle injury. Myoglobin concentrations appear to be greatly influenced by the extent and duration of the muscle cramps induced by the electrical current. Correct interpretation of serum myoglobin concentrations depends on the knowledge of events surrounding the lethal electrical shock. Postmortem determination of serum myoglobin concentrations alone is, therefore, not sufficient to establish intravital exposure to electrical current and can aid the diagnosis only in special cases.

Adolescent↗
PubMed1991

Muscle ATP and lactate and the release of myoglobin and carbanhydrase III in acute lower-limb ischaemia.

Serum-myoglobin and carbanhydrase III (S-CAIII), a specific muscle enzyme, were measured on admission, during surgery and in the postoperative period in 23 patients with acute lower-limb ischaemia and in 21 patients with chronic limb ischaemia in order to evaluate these molecules as possible markers of the degree of clinical ischaemia. The muscle contents of ATP and lactate were determined in muscle biopsies from patients with acute ischaemia on admission. Unlike S-myoglobin and S-CAIII they discriminated between cases which required subsequent amputation from those which did not. Clinical signs of ischaemia were, however, of no value in this respect and there were no correlations between clinical signs or the duration of ischaemia and S-myoglobin or S-CAIII or the contents of ATP or lactate in muscle tissue. The levels of S-myoglobin and S-CAIII correlated well (r = 0.95, p less than 0.0001). In patients who subsequently required an amputation S-myoglobin increased ten-fold (i.e., from 24-48 h postoperatively in acute arterial ischaemia and from 3 h postoperatively in patients with chronic limb ischaemia). In patients with a successful revascularisation S-myoglobin returned to normal levels. It is concluded that in this investigation S-myoglobin had no prognostic value on admission and that S-myoglobin analyses in the postoperative course may be useful for making clinical decisions concerning impending recirculation failures.

Acute Disease↗
PubMed2000

Body size and skeletal muscle myoglobin of cetaceans: adaptations for maximizing dive duration.

Cetaceans exhibit an exceptionally wide range of body mass that influence both the capacities for oxygen storage and utilization; the balance of these factors is important for defining dive limits. Furthermore, myoglobin content is a key oxygen store in the muscle as it is many times higher in marine mammals than terrestrial mammals. Yet little consideration has been given to the effects of myoglobin content or body mass on cetacean dive capacity. To determine the importance of myoglobin content and body mass on cetacean diving performance, we measured myoglobin content of the longissimus dorsi for ten odontocete (toothed whales) and one mysticete (baleen whales) species ranging in body mass from 70 to 80000 kg. The results showed that myoglobin content in cetaceans ranged from 1.81 to 5.78 g (100 g wet muscle)(-1). Myoglobin content and body mass were both positively and significantly correlated to maximum dive duration in odontocetes; this differed from the relationship for mysticetes. Overall, the combined effects of body mass and myoglobin content accounts for 50% of the variation in cetacean diving performance. While independent analysis of the odontocetes showed that body mass and myoglobin content accounts for 83% of the variation in odontocete dive capacity.

Adaptation, Physiological↗
PubMedDate not supplied

Effect of cast solvent on the electron transfer reaction for poly(ethylene oxide)-modified myoglobin on the electrode in poly(ethylene oxide) oligomers.

Myoglobin from horse skeletal muscle was modified with poly(ethylene oxide) (PEO) with an average molecular weight of 2000 or 5000. Myoglobin was soluble after this modification in several organic solvents and PEO oligomers. The electron transfer reactions of PEO-modified myoglobin cast on the indium tin oxide (ITO) glass electrode were investigated by cyclic voltammetry. The PEO-modified myoglobin, cast on the electrode from water or a methanol solution, showed quasi-reversible redox reactions in PEO (average MW of 400). On the other hand, no redox response was seen in PEO-modified myoglobin cast on it using chloroform or benzene as a casting solvent. A clear redox response of the PEO-modified myoglobin was observed after methanol treatment of these layers cast from chloroform or a benzene solution. This suggests that the conformational change of the adsorbed PEO-modified myoglobin layer on the ITO electrode cast from chloroform or a benzene solution was not irreversible. The cast condition of PEO-modified myoglobin on the ITO glass electrode was revealed to affect the electron transfer reaction for protein considerably in PEO oligomers.

Animals↗
PubMed1991

Contributions of residue 45(CD3) and heme-6-propionate to the biomolecular and geminate recombination reactions of myoglobin.

Overall association and dissociation rate constants were measured at 20 degrees C for O2, CO, and alkyl isocyanide binding to position 45 (CD3) mutants of pig and sperm whale myoglobins and to sperm whale myoglobin reconstituted with protoheme IX dimethyl ester. In pig myoglobin, Lys45(CD3) was replaced with Arg, His, Ser, and Glu; in sperm whale myoglobin, Arg45(CD3) was replaced with Ser and Gly. Intramolecular rebinding of NO, O2, and methyl isocyanide to Arg45, Ser45, Glu45, and Lys45(native) pig myoglobins was measured following 35-ps and 17-ns excitation pulses. The shorter, picosecond laser flash was used to examine ligand recombination from photochemically produced contact pairs, and the longer, nanosecond flash was used to measure the rebinding of ligands farther removed from the iron atom. Mutations at position 45 or esterification of the heme did not change significantly (less than or equal to 2-fold) the overall association rate constants for NO, CO, and O2 binding at room temperature. These data demonstrate unequivocally that Lys(Arg)45 makes little contribution to the outer kinetic barrier for the entry of diatomic gases into the distal pocket of myoglobin, a result that contradicts a variety of previous structural and theoretical interpretations. However, the rates of geminate recombination of NO and O2 and the affinity of myoglobin for O2 were dependent upon the basicity of residue 45. The series of substitutions Arg45, Lys45, Ser45, and Glu45 in pig myoglobin led to a 3-fold decrease in the initial rate for the intramolecular, picosecond rebinding of NO and 4-fold decrease in the geminate rate constant for the nanosecond rebinding of O2. (ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Myoglobin levels in mothers and neonates.

Myoglobin levels were measured in 70 maternal and 74 cord sera drawn immediately after delivery. The mean cord myoglobin was 28 ng/ml. Myoglobin levels increased with birthweight, and black infants tended to have slightly higher levels than white babies. Myoglobin levels were not elevated in babies with fetal distress (evidenced by abnormal monitor tracings or meconium staining) compared to babies with no distress. Maternal myoglobin (18 +/- 15.3 ng/ml) was about 10 ng/ml lower than cord levels and there was little correlation between the two. Mothers differed among themselves only with respect to complications of labor and delivery. Those with complications had significantly higher myoglobin levels (29 +/- 24.1 ng/ml) than mothers without difficulties (15 +/- 10.0 ng/ml, P less than 0.05). The fetal myoglobin level was relatively independent of the mother's. While high or potentially toxic myoglobin levels were not observed in this study, it appears that the fetus may be protected by the placental barrier.

Apgar Score↗
PubMed2000

Very early risk stratification after thrombolytic therapy with a bedside myoglobin assay and the 12-lead electrocardiogram.

BACKGROUND: Available clinical criteria to estimate prognosis in patients with evolving ST-segment elevation myocardial infarction do not consider the impact of reperfusion therapy and do not incorporate measurement of baseline levels of cardiac serum markers. We evaluated the combination of a baseline myoglobin assay and early (60- to 90-minute) ST resolution for risk stratification after ST-segment elevation myocardial infarction. METHODS: In a prospective substudy of the Intravenous nPA for Treatment of Infarcting Myocardium Early-II (InTIME-II) trial carried out in 2079 patients, a rapid qualitative assay for myoglobin was performed immediately before thrombolysis. Serial 12-lead electrocardiograms were performed at baseline and 60 to 90 minutes after thrombolysis. ST resolution was categorized as complete (>/=70%), partial (30% to <70%), or none (<30%). RESULTS: Mortality rate at 30 days was 3.3% in the 905 patients with a negative baseline myoglobin assay versus 8.9% in the 527 patients with a positive assay (P <.0001). Mortality rate was lowest (2.4%) among the 614 patients with complete ST resolution, intermediate (4.9%) among the 512 patients with partial ST resolution, and highest (8.1%) among the 540 patients with no ST resolution (P <.0001 for trend). In a logistic regression model incorporating other baseline predictors of 30-day mortality rate, both a positive myoglobin assay (relative risk 1.98, 95% confidence interval 1.00-3.90) and ST resolution <70% (relative risk 2.86, 95% confidence interval 1.22-6.69) were independently associated with increased mortality rate. At 30 days, mortality rate was 0.4% among patients with a negative myoglobin assay and complete ST resolution, 4.8% among patients with either a positive myoglobin assay or ST resolution <70%, and 9.6% among those with both a positive myoglobin ratio and ST resolution <70% (P <.001 for trend). CONCLUSIONS: Within 90 minutes after administering thrombolytic therapy for acute myocardial infarction, clinicians can determine the risk for death at the patient's bedside with a hand-held myoglobin assay and 2 serial 12-lead electrocardiograms. A strategy using these 2 simple, rapid, and inexpensive tests may facilitate triage after thrombolytic therapy.

Adult↗