Disease relevance of Mb

• Compensatory hypertrophy of the plantaris muscle was induced by the bilateral ablation of the medial and lateral heads of the gastrocnemius muscle, and the effect of compensatory hypertrophy on the [Mb] of the plantaris muscle was examined at 7, 21 and 42 days post-ablation [1].
• During transitions to anoxia, 68 +/- 2% (SE) of the NIRS signal was due to Mb and the rest to cytochrome oxidase [2].
• The question was studied of whether myoglobin (Mb), when released into the general circulation during hemorrhagic hypotension (HH), causes disturbances of renal blood flow [3].
• Heme proteins such as myoglobin or hemoglobin, when released into the extracellular space, can instigate tissue toxicity [4].
• Myoglobin is directly implicated in the pathogenesis of renal failure in rhabdomyolysis [4].

High impact information on Mb

• Skin heme oxygenase is locally elevated by stimuli such as tissue injury and injections of whole blood, myoglobin, and hematin [5].
• Effects of inorganic iron and myoglobin on in vitro proximal tubular lipid peroxidation and cytotoxicity [6].
• Perfusion of the LS for less than 2 min with cast-forming proteins (Bence Jones protein [BJP3] and myoglobin) decreased chloride absorption and elevated early distal tubule fluid (ED) [Cl-], compared with results obtained with control perfusions that used ATF alone [7].
• Putrescine itself enhanced the reperfusion-evoked release of myoglobin and protein in the absence of DFMO [8].
• In resting glands, the tracers microperoxidase , cytochrome c, myoglobin, tyrosinase (subunits), and hemoglobin were restricted to the luminal space of the acini and ducts [9].

Chemical compound and disease context of Mb

• Deferoxamine addition, reported to protect against in vivo acute renal failure, paradoxically increased .OH levels (approximately 25%) in myoglobin-loaded, but not control, PTSs [10].
• The present study was undertaken to assess whether isoflurane anesthesia might confer in vivo cytoprotection, possibly by causing renal tubular inorganic fluoride exposure, thereby mitigating a combined myoglobin/ATP depletion model of acute renal failure (glycerol-induced ARF) [11].
• MEASUREMENTS AND MAIN RESULTS: Blood collections were used to measure blood glucose, bacteremia, plasma protein C, D-dimer, hormones, chemokines, cytokines, and myoglobin (as a marker of organ damage) [12].
• BDM-mediated inhibition of contracture was associated with accelerated cell injury, as defined by: the uptake of an extracellular marker (trypan blue) by the cardiomyocytes, by direct analysis of myoglobin released into the supernatant and by ultrastructural demonstration of defects in sarcolemmal membrane integrity [13].
• We tested the hypothesis that endothelin-1, the most potent renal vasoconstrictor known, plays a role in the renal toxicity of myoglobin [14].

Biological context of Mb

• When oxygen consumption was increased by carbonyl cyanide m-chlorophenylhydrazone (CCCP) during superfusion of cells with 4% oxygen, PO(2) at the cell core dropped to 2.3 mmHg, whereas Mb near the plasma membrane was almost fully saturated with oxygen [15].
• These findings show that Mb gene expression is induced by T3 [16].
• Heat acclimation (33 degrees C for 4 weeks, 11 weeks old) did not influence Mb levels of the tissues [17].
• We examine this phenomenon by analyzing the behavior and the kinetics of Mb oxygenation and cytochrome aa3 (cytaa3) redoxation [18].
• It is concluded that the observed changes in renal blood flow contribute to the known direct nephrotoxic potential of Mb [3].

Anatomical context of Mb

• The results suggest that bradykinin-induced NO does not interact significantly with cellular Mb to produce an NMR-detectable quantity of metMb in the perfused rat myocardium [19].
• It is difficult, and in some cases impossible, to study the relationship between the myoglobin concentration and the oxidative capacity of individual muscle cells because myoglobin has to be fixed in situ whereas determination of oxidative capacity, for example, succinate dehydrogenase activity, requires unfixed cryostat sections [20].
• Myoglobin plays various roles in oxygen supply to muscle mitochondria [20].
• On ligation of the left anterior descending coronary artery, the Mb signal at 78 parts/million (ppm) appears, along with a peak shoulder assigned to the corresponding signal of Hb [21].
• After cryolesion of the sciatic nerve, the Mb concentrations in the tibialis anterior, peroneus longus, and EDL muscles increased, reaching maximal values on days 16-21 [22].

Associations of Mb with chemical compounds

• In the same spectral region, nitrite oxidation of Mb produces a set of signals at -3.7 and -4.7 ppm at 35 degrees C. Previous studies have confirmed the visibility of metMb signals in perfused rat myocardium [19].
• Bradykinin still triggers a similar physiological response even in the presence of CO that is sufficient to inhibit 86% Mb [19].
• In solution, nitrite oxidization of Mb produces a characteristic set of paramagnetically shifted (1)H NMR signals [19].
• The results show that it is possible to use serial sections for the determination of the myoglobin concentration and succinate dehydrogenase activity, and indicate that myoglobin can lead to a substantial reduction (18-60%) of the extracellular oxygen tension required to prevent an anoxic core in muscle cells [20].
• Despite the increased respiration and work, no deoxymyoglobin signal is detected, implying that the intracellular O2 level still saturates MbO2, well above the PO2 at 50% saturation of Mb [21].

Regulatory relationships of Mb

• In addition, exposure of the kidney to myoglobin after glycerol injection induced heme oxygenase [23].

Other interactions of Mb

• The middle and caudal sections had significantly higher mean levels of CS, LDH, and Mb than the cranial section, which may be correlated with power production during swimming [24].
• Distribution and nature of the reactive substance to Mb antiserum were compared to those of desmin antiserum [25].
• HO-2 utilized as substrate, Fe-protoporphyrin, Fe-hematoporphyrin, and Fe-hematoporphyrin acetate; it did not degrade intact purified rat liver cytochromes b5 and P-450 LM2, catalase, cytochrome c, hemoglobin, or myoglobin [26].
• Increased glomerular filtration and tubular uptake of LMWP were induced by i.v. and i.p. injections of myoglobin and cationic and anionic lysozyme [27].
• Hence, the heme pocket interior in cytochrome b5 is judged much less polar and less sterically accommodating than that of myoglobin [28].

Analytical, diagnostic and therapeutic context of Mb

• It also seems reasonable that the peroxidative activity of Mb(IV), during oxygenated reperfusion, might lead to cellular damage if this hypervalent form of Mb is not reduced [29].
• Here we investigate, by dose-response (0.3-100 microg/100 g BW, i.p., 5 days) and time-course studies (100 microg/100 g BW, i.v., from 0.5 to 24h), whether T3 affects the Mb mRNA and protein expression in atrium (A) and ventricle (V), by Northern and Western blot [30].
• Radioimmunoassay of myoglobin (Mb) was performed in rat hind limb muscles after surgical denervation and during reinnervation following cryolesion of the sciatic nerve [22].
• However, the [Mb] expressed as mg g(-1) protein weight was not significantly different between the ablation and control groups throughout the experimental period [1].
• Rat Mb was isolated from the skeletal muscle; monospecificity of the rat antiserum was confirmed by the immunoblotting procedures [25].

References