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The FEBS Journal Jan 2010One of the least recognized causes of cellular damage during ex vivo preservation of red blood cells is oxidative injury to the hemoglobin. The latter has been... (Review)
Review
One of the least recognized causes of cellular damage during ex vivo preservation of red blood cells is oxidative injury to the hemoglobin. The latter has been associated with hemolysis through the release of toxic substances and oxidation of vital cell components. This review delineates some of the major pathways that link hemoglobin oxidation and cellular damage, and summarizes the incidence of red blood cell oxidative injury during hypothermic storage, cryopreservation and desiccation stress. Red blood cell hypothermic storage, despite its success, is not exempt from oxidative injury. Growing evidence portrays a time-dependant oxidative assault including formation of reactive oxygen species, attachment of denatured hemoglobin to membrane phospholipids and the release of hemoglobin-containing membrane microvesicles throughout storage. Similar symptoms have been observed in attempts to stabilize red blood cells in the dried state, in which methemoglobin levels of reconstituted red blood cells reached 50%. Factors affecting the rate of hemoglobin oxidation during red blood cell ex vivo storage include compromised antioxidant activity, high concentrations of glucose in the storage media and the presence of molecular oxygen. Hemoglobin oxidation largely dictates our ability to effectively preserve red blood cells. Understanding its origins along with investigating methods to minimize it can significantly improve the quality of our future blood products.
Topics: Blood Preservation; Cold Temperature; Cryopreservation; Cryoprotective Agents; Desiccation; Erythrocyte Membrane; Erythrocytes; Hemoglobins; Humans; Hydrogen Peroxide; In Vitro Techniques; Lipid Peroxidation; Methemoglobin; Models, Biological; Oxidation-Reduction; Oxyhemoglobins; Protein Denaturation; Reactive Oxygen Species
PubMed: 19968714
DOI: 10.1111/j.1742-4658.2009.07472.x -
The Journal of Biological Chemistry Jun 1981A soluble erythrocyte cytochrome b5 was purified as the substrate of methemoglobin reductase and an electron carrier to methemoglobin. The isoelectric point of this...
A soluble erythrocyte cytochrome b5 was purified as the substrate of methemoglobin reductase and an electron carrier to methemoglobin. The isoelectric point of this protein was at pH 4.3, and E0' was -0.010 at pH 7.0.. The Km value of the enzyme for this protein was 1 x 10(-4) M, and the turnover number (k5) was 3.4 x 10(4) min-1, with NADH as an electron donor at pH 7.0. The optimum pH of the enzyme was pH 4.6 for ferricyanide and pH 5.5 for cytochrome b5, with a shoulder of activity at pH 7 to 9 for both substrates. The rate equation which represents the reduction of either methemoglobin or cytochrome c was obtained as a function of methemoglobin or cytochrome c, methemoglobin reductase, and cytochrome b5 by considering the E . S complex for both reductase and cytochrome b5, and the rate constants involved were determined. The rate constants between methemoglobin and reduced cytochrome b5 (k1, M-1 min-1) were 1.6 x 10(4), 3.1 x 10(6), and 4.1 x 10(6) at pH 7.0, pH 5.2, and pH 5.0, respectively. The rate constants between the reduced enzyme and oxidized cytochrome b5 (k'3, M-1 min-1) were 4.3 x 10(8), 12 x 10(8), and 9.3 x 10(8) at pH 7.0, pH 5.2, and pH 5.0, respectively. The rate constant between reduced hemoglobin and oxidized cytochrome b5 (k2) was 35 M-1 min-1 at pH 7.0. The theoretical Km for methemoglobin was 2.1 M at an infinite enzyme concentration at pH 7.0
Topics: Cytochrome-B(5) Reductase; Cytochromes; Cytochromes b5; Erythrocytes; Humans; Hydrogen-Ion Concentration; Kinetics; Methemoglobin; NADH, NADPH Oxidoreductases; Oxidation-Reduction; Spectrophotometry
PubMed: 7240153
DOI: No ID Found -
Journal of Biomedical Optics Jun 2021Noninvasive diffuse optical spectroscopy (DOS) is a promising adjunct diagnostic imaging technique for distinguishing benign and malignant breast lesions. Most DOS...
SIGNIFICANCE
Noninvasive diffuse optical spectroscopy (DOS) is a promising adjunct diagnostic imaging technique for distinguishing benign and malignant breast lesions. Most DOS approaches require normalizing lesion biomarkers to healthy tissue since major tissue constituents exhibit large interpatient variations. However, absolute optical biomarkers are desirable as it avoids reference measurements which may be difficult or impractical to acquire.
AIM
Our goal is to determine whether absolute measurements of minor absorbers such as collagen and methemoglobin (metHb) can successfully distinguish lesions. We hypothesize that metHb would exhibit less interpatient variability and be more suitable as an absolute metric for malignancy. However, we would expect collagen to exhibit more variability, because unlike metHb, collagen is also present in the healthy tissue.
APPROACH
In this retrospective clinical study, 30 lesions with breast imaging reporting and database system score ( BIRADS ) > = 3 (12 benign and 18 malignant) measured with broadband quantitative DOS were analyzed for their oxyhemoglobin (HbO), deoxyhemoglobin (HHb), water, lipids, collagen, metHb concentrations, and optical scattering characteristics. Wilcoxon rank sum test was used to compare benign and malignant lesions for all variables in both normalized and absolute forms.
RESULTS
Among all absolute DOS parameters considered, only absolute metHb was observed to be significant for lesion discrimination (0.43 ± 0.18 μM for benign versus 0.87 ± 0.32 μM for malignant, p = 0.0002). Absolute metHb concentration was also determined to be the best predictor of malignancy with an area under the curve of 0.89.
CONCLUSIONS
Our findings demonstrate that lesion metHb concentration measured by DOS can improve noninvasive optical diagnosis of breast malignancies. Since metHb concentration found in normal breast tissue is extremely low, metHb may be a more direct indicator of malignancy that does not depend on other biomarkers found in healthy tissue with significant variability. Furthermore, absolute parameters require reduced measurement time and can be utilized in cases where healthy reference tissue is not available.
Topics: Breast; Breast Neoplasms; Female; Humans; Methemoglobin; Retrospective Studies; Spectrum Analysis
PubMed: 34189876
DOI: 10.1117/1.JBO.26.6.065004 -
Anesthesia Progress 2013The purpose of this study was to measure and compare peak methemoglobin levels and times to peak methemoglobin levels following the use of prilocaine and lidocaine in... (Randomized Controlled Trial)
Randomized Controlled Trial
The purpose of this study was to measure and compare peak methemoglobin levels and times to peak methemoglobin levels following the use of prilocaine and lidocaine in precooperative children undergoing comprehensive dental rehabilitation under general anesthesia. Ninety children, 3-6 years of age, undergoing dental rehabilitation under general anesthesia were enrolled and randomly assigned into 3 equal groups: group 1, 4% prilocaine plain, 5 mg/kg; group 2, 2% lidocaine with 1:100,000 epinephrine, 2.5 mg/kg; and group 3, no local anesthetic. Subjects in groups 1 and 2 were administered local anesthetic prior to restorative dental treatment. Methemoglobin levels (SpMET) were measured and recorded throughout the procedure using a Masimo Radical-7 Pulse Co-Oximeter (Masimo Corporation, Irvine, Calif, RDS-1 with SET software with methemoglobin interface). Data were analyzed using chi-square, one-way analysis of variance (ANOVA), and Pearson correlation (significance of P < .05). Group 1 had a significantly higher mean peak SpMET level at 3.55% than groups 2 and 3 at 1.63 and 1.60%, respectively. The mean time to peak SpMET was significantly shorter for group 3 at 29.50 minutes than that of group 1 at 62.73 and group 2 at 57.50 minutes. Prilocaine, at 5 mg/kg in pediatric dental patients, resulted in significantly higher peak SpMET levels than lidocaine and no local anesthetic. In comparison to no local anesthetic, the administration of prilocaine and lidocaine caused peak SpMET levels to occur significantly later in the procedure.
Topics: Analysis of Variance; Anesthesia, Dental; Anesthesia, General; Anesthetics, Local; Chi-Square Distribution; Child; Child, Preschool; Female; Humans; Injections, Intravenous; Lidocaine; Male; Methemoglobin; Methemoglobinemia; Mouth Rehabilitation; Oximetry; Prilocaine; Statistics, Nonparametric
PubMed: 24010987
DOI: 10.2344/0003-3006-60.3.99 -
Redox Biology Jan 2013Acute anemia increases the risk for perioperative morbidity and mortality in critically ill patients who experience blood loss and fluid resuscitation (hemodilution).... (Review)
Review
Acute anemia increases the risk for perioperative morbidity and mortality in critically ill patients who experience blood loss and fluid resuscitation (hemodilution). Animal models of acute anemia suggest that neuronal nitric oxide synthase (nNOS)-derived nitric oxide (NO) is adaptive and protects against anemia-induced mortality. During acute anemia, we have observed a small but consistent increase in methemoglobin (MetHb) levels that is inversely proportional to the acute reduction in Hb observed during hemodilution in animals and humans. We hypothesize that this increase in MetHb may be a biomarker of anemia-induced tissue hypoxia. The increase in MetHb may occur by at least two mechanisms: (1) direct hemoglobin oxidation by increased nNOS-derived NO within the perivascular tissue and (2) by increased deoxyhemoglobin (DeoxyHb) nitrite reductase activity within the vascular compartment. Both mechanisms reflect a potential increase in NO signaling from the tissue and vascular compartments during anemia. These responses are thought to be adaptive; as deletion of nNOS results in increased mortality in a model of acute anemia. Finally, it is possible that prolonged activation of these mechanisms may lead to maladaptive changes in redox signaling. We hypothesize, increased MetHb in the vascular compartment during acute anemia may reflect activation of adaptive mechanisms which augment NO signaling. Understanding the link between anemia, MetHb and its treatments (transfusion of stored blood) may help us to develop novel treatment strategies to reduce the risk of anemia-induced morbidity and mortality.
Topics: Acute Disease; Anemia; Animals; Biomarkers; Humans; Methemoglobin; Oxidative Stress
PubMed: 24024138
DOI: 10.1016/j.redox.2012.12.003 -
PloS One 2021A new method for hemoglobin (Hb) deoxygenation, in suspension or within red blood cells (RBCs) is described using the commercial enzyme product, EC-Oxyrase®. The...
A new method for hemoglobin (Hb) deoxygenation, in suspension or within red blood cells (RBCs) is described using the commercial enzyme product, EC-Oxyrase®. The enzymatic deoxygenation method has several advantages over established deoxygenation methodologies, such as avoiding side reactions that produce methemoglobin (metHb), thus eliminating the need for an inert deoxygenation gas and airtight vessel, and facilitates easy re-oxygenation of Hb/RBCs by washing with a buffer that contains dissolved oxygen (DO). The UV-visible spectra of deoxyHb and metHb purified from human RBCs using three different preparation methods (sodium dithionite [to produce deoxyHb], sodium nitrite [to produce metHb], and EC-Oxyrase® [to produce deoxyHb]) show the high purity of deoxyHb prepared using EC-Oxyrase® (with little to no metHb or hemichrome production from side reactions). The oxyHb deoxygenation time course of EC-Oxyrase® follows first order reaction kinetics. The paramagnetic characteristics of intracellular Hb in RBCs were compared using Cell Tracking Velocimetry (CTV) for healthy and sickle cell disease (SCD) donors and oxygen equilibrium curves show that the function of healthy RBCs is unchanged after EC-Oxyrase® treatment. The results confirm that this enzymatic approach to deoxygenation produces pure deoxyHb, can be re-oxygenated easily, prepared aerobically and has similar paramagnetic mobility to existing methods of producing deoxyHb and metHb.
Topics: Anemia, Sickle Cell; Female; Hemoglobins; Humans; Magnetics; Male; Methemoglobin; Oxygen; Oxyhemoglobins; Tissue Donors
PubMed: 34478473
DOI: 10.1371/journal.pone.0257061 -
Free Radical Biology & Medicine Dec 2012Plasma hemoglobin (Hb) released during intravascular hemolysis has been associated with numerous deleterious effects that may stem from increased nitric oxide (NO)...
Plasma hemoglobin (Hb) released during intravascular hemolysis has been associated with numerous deleterious effects that may stem from increased nitric oxide (NO) scavenging, but has also been associated with reactive oxygen species generation and platelet activation. Therapies that convert plasma oxyHb to metHb, or metHb to iron-nitrosyl Hb, could be beneficial because these species do not scavenge NO. In this study, we investigated the effects of Angeli's salt (AS; sodium α-oxyhyponitrite, Na2N2O3), a nitroxyl (HNO) and nitrite (NO2(-)) donor, on plasma Hb oxidation and formation of iron-nitrosyl Hb from metHb and on the vasoactivity of plasma Hb. We hypothesized that AS could ameliorate hemolysis-associated pathology via its preferential reactivity with plasma Hb, as opposed to red-cell-encapsulated Hb, and through its intrinsic vasodilatory activity. To test this hypothesis, we infused (n=3 per group) (1) cell-free Hb and AS, (2) cell-free Hb+0.9% NaCl, (3) AS+3% albumin, and (4) 3% albumin+0.9% NaCl (colloid controls for Hb and AS, respectively) in a canine model. Co-infusion of AS and cell-free Hb led to preferential conversion of plasma Hb to metHb, but the extent of conversion was lower than anticipated based on the in vivo concentration of AS relative to plasma Hb. This lower metHb yield was probably due to reactions of nitroxyl-derived AS with plasma components such as thiol-containing compounds. From a physiological and therapeutic standpoint, the infusion of Hb alone led to significant increases in mean arterial pressure (p=0.03) and systemic vascular resistance index (p=0.01) compared to controls. Infusion of AS alone led to significant decreases in these parameters and co-infusion of AS along with Hb had an additive effect in reversing the effects of Hb alone on the systemic circulation. Interestingly, in the pulmonary system, the decrease in pressure when AS was added to Hb was significantly less than would have been expected compared to the effects of Hb and AS alone, suggesting that inactivation of scavenging with AS reduced the direct vasodilatory effects of AS on the vasculature. We also found that AS reduced platelet activation when administered to whole blood in vitro. These data suggest that AS-like compounds could serve as therapeutic agents to counteract the negative vasoconstrictive consequences of hemolysis that occur in hemolytic anemias, transfusion of stored blood, and other diseases. Increases in metHb in the red blood cell, the potential of AS for neurotoxicity, and hypotension would need to be carefully monitored in a clinical trial.
Topics: Animals; Blood Platelets; Blood Pressure; Dogs; Erythrocytes; Heart Rate; Hemolysis; Leukocytes; Methemoglobin; Nitrites; Oxidation-Reduction; Pulmonary Artery; Vasoconstriction; Vasodilator Agents
PubMed: 23099417
DOI: 10.1016/j.freeradbiomed.2012.10.548 -
Scandinavian Journal of Work,... 1993
Review
Topics: Air Pollutants; Animals; Dose-Response Relationship, Drug; Humans; Leukocyte Count; Lung; Methemoglobin; Nitric Oxide; Reactive Oxygen Species
PubMed: 8209195
DOI: No ID Found -
Scientific Reports Jan 2020The invasive brown treesnake (Boiga irregularis) has extirpated much of Guam's native birdlife and poses significant threats to other parts of the western Pacific....
The invasive brown treesnake (Boiga irregularis) has extirpated much of Guam's native birdlife and poses significant threats to other parts of the western Pacific. Acetaminophen (APAP) is a proven lethal oral toxicant in reptiles but the physiological mechanism is unknown. The effects of a lethal APAP oral dose on methemoglobin (MetHb, non-oxygen carrying form) levels and other blood parameters were examined in brown treesnakes. Co-oximetry was used to measure MetHb (%) and other hemoglobin species. Assessment of red blood cell integrity, white blood cell differential counts, and plasma biochemical analyses were conducted to evaluate tissue damage, stress, and liver function. Changes in oxygen carrying capacity were noted in APAP-treated snakes indicated by a 50-60% increase in methemoglobin levels and a 40% decrease in oxyhemoglobin (oxygen-carrying form) levels compared to controls. APAP-treated snakes had decreased lymphocyte and increased monocyte counts while also having increased levels of blood analytes associate with impaired liver function and muscle damage. The proximate cause of death in APAP-treated snakes was likely acute methemoglobinemia and respiratory failure due to severe hypoxia with no observed signs of distress or pain. An orally-ingested lethal dose of APAP appears to be a humane method for lethal control of this species.
Topics: Acetaminophen; Animals; Blood Cell Count; Eating; Methemoglobin; Oxyhemoglobins; Pest Control, Biological; Snakes
PubMed: 31964901
DOI: 10.1038/s41598-019-56216-1 -
International Journal of Molecular... Dec 2021Dinitrosyl iron complexes (DNICs) are a physiological form of nitric oxide (NO) in an organism. They are able not only to deposit and transport NO, but are also to act...
Dinitrosyl iron complexes (DNICs) are a physiological form of nitric oxide (NO) in an organism. They are able not only to deposit and transport NO, but are also to act as antioxidant and antiradical agents. However, the mechanics of hemoglobin-bound DNICs (Hb-DNICs) protecting Hb against peroxynitrite-caused, mediated oxidative modification have not yet been scrutinized. Through EPR spectroscopy we show that Hb-DNICs are destroyed under the peroxynitrite action in a dose-dependent manner. At the same time, DNICs inhibit the oxidation of tryptophan and tyrosine residues and formation of carbonyl derivatives. They also prevent the formation of covalent crosslinks between Hb subunits and degradation of a heme group. These effects can arise from the oxoferryl heme form being reduced, and they can be connected with the ability of DNICs to directly intercept peroxynitrite and free radicals, which emerge due to its homolysis. These data show that DNICs may ensure protection from myocardial ischemia.
Topics: Animals; Cattle; Electron Spin Resonance Spectroscopy; Humans; Iron; Methemoglobin; Nitrogen Oxides; Oxidation-Reduction; Peroxynitrous Acid; Tryptophan; Tyrosine
PubMed: 34948445
DOI: 10.3390/ijms222413649