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Carbon Monoxide Poisoning, Methemoglobinemia, and Sulfhemoglobinemia
Published in Harold R. Schumacher, William A. Rock, Sanford A. Stass, Handbook of Hematologic Pathology, 2019
Oxidation of hemoglobin can occur by exogenous sources. One example is Cu2+, which binds Cys-β93 with high affinity and multiple other sites with low affinity. It converts the iron attached to the heme of the β chains into Met. Drugs can also oxidize hemoglobin (see below). Methemoglobin induces the denaturation of hemoglobin with hemichrome formation. Heinz bodies, made of hemichromes, are common in methemoglobinemia, the product of hemoglobin denaturation. Hemichromes are generated by heme dissociation (favored in met-Hb) from the heme pocket and rebinding elsewhere in globin after the α or β chains. It is understandable, then, that any weakening of the Hb bond with heme will accelerate denaturation.
Conformational changes of β-thalassemia major hemoglobin and oxidative status of plasma after in vitro exposure to extremely low-frequency electromagnetic fields: An artificial neural network analysis
Published in Electromagnetic Biology and Medicine, 2021
Saeideh Rahmani, Hadi Ansarihadipour, Mohamad Reza Bayatiani, Ali Khosrowbeygi, Saeid Babaei, Yousef Rasmi
Red blood cells were washed three times with cold isotonic phosphate buffer (310 mOsM, and pH 7.6) and lysed with cold hypotonic phosphate buffer, (20 mOsM, and pH 7.6). Optical absorption of Hb was measured at 200–700 nm to investigate the structural modifications of Hb (Figure 1). the absorption increase at 340 nm indicates the non-covalent bond between histidine globin and heme ring. The optical absorption at 420 nm declares the interaction between heme ring and globin chain. The enhanced concentration of hemichrome is indicated by an increase in absorbance at 560 nm. The absorbance at 577 nm demonstrates hem–hem interaction. An increase in absorbance at 577 nm represents conversion of oxyHb to metHb. Also met-Hb concentration is correlated with a peak in Hb absorption at 630 nm. The Hb absorbance at 630 nm corresponds to metHb concentration (Ibrahim et al. 2008). Hb concentration was estimated by cyanmethemoglobin method. The oxidation of Hb gives metHb and hemichrome. In this study, the micromolar concentrations of oxyHb, metHb, and hemichrome were calculated according to optical densities at 560, 577 and 630 nm (Ibrahim et al. 2008).
Increasing the stability of Lumbricus terrestris erythrocruorin via poly(acrylic acid) conjugation
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Kyle Spivack, Matthew Tucker, Devon Zimmerman, Matthew Nicholas, Osheiza Abdulmalik, Noelle Comolli, Jacob Elmer
However, despite the increase in Tm, pasteurization and autoclave experiments revealed that the LPE nanoparticles are still susceptible to oxidation and partial denaturation at high temperatures (even in the presence of CO). In addition, CD spectra of LPE samples exposed to high temperatures also show a loss of secondary structure (Figure S3). This loss in 2’ structure leads to a collapse of the heme pocket, which brings the distal histidine much closer to the heme group and induces formation of the hemichrome. The absence of hemichrome formation in the experiments by Mudhivarthi et al. may be attributed to the fact that HbA has a much larger heme pocket than LtEc, thereby decreasing the likelihood of contact between the heme and distal histidine [11]. In conclusion, while it has been previously shown that human HBOCs can be sterilized via pasteurization in the presence of CO [21], our results suggest that it is not possible to sterilize native LtEc or LPE particles with pasteurization or autoclaving. Therefore, additional experiments will need to be conducted to develop a sterilization method that inactivates viruses while maintaining the O2 transport properties of LtEc and/or LPE.
Protective properties of Myrtus communis extract against oxidative effects of extremely low-frequency magnetic fields on rat plasma and hemoglobin
Published in International Journal of Radiation Biology, 2019
Fatemeh Seif, Mohamad Reza Bayatiani, Hadi Ansarihadipour, Ghasem Habibi, Samira Sadelaji
Hemichrome concentration was 0.34 μM in control group, which increased to 4.99 μmol after magnetic field exposure, indicating a 14.7-fold increase in Hb oxidation (Figure 4(C)). After administration of the M. communis extract, the hemichrome concentration was reduced to 2.21 μM (p < .001), which was in association with the increase in Hb absorption at 560 nm (Figure 5).