Determination of Ferrihemoglobin in Blood
Manfred Kiese in Methemoglobinemia: A Comprehensive Treatise, 2019
Optical methods for the detection and determination of ferrihemoglobin are used since the spectroscopic observation of the absorption band of ferrihemoglobin in acid solution around 630 nm. Large proportions of ferrihemoglobin in blood are easily detected with a small spectroscope, and a dilution technique allows a rough guess of the size of the portion. Absorbance coefficients of ferrihemoglobin at five wavelengths and pH 6.2 to 8.8 may be found in Benesch. Ferrihemoglobin can be estimated in the presence of ferrohemoglobin and its compounds with oxygen or carbon monoxide. Unless a blood sample is analyzed for ferrihemoglobin immediately, ferrihemoglobin content found may be different from the content at the time the sample was taken. Ferrihemoglobin is reduced in a blood sample with intact red cells in vitro . The ferrihemoglobin reduction in vitro may be diminished by inhibition of glycolysis with fluoride or iodoacetate.
Introduction
Manfred Kiese in Methemoglobinemia: A Comprehensive Treatise, 2019
Heme ferro protoporphyrin, quickly autoxidizes in aqueous solution. The binding of ferro protoporphyrin to the protein globin in its hydrophobic pockets enables the ferrous iron to form a reversible compound with molecular oxygen, oxyhemoglobin, and inhibits the autoxidation of ferrous heme to ferric heme, i.e., the formation of methemoglobin or ferrihemoglobin, but it does not fully prevent the latter reaction. The term “methemoglobinemia” was used, long before the existence of “normal” ferrihemoglobin was known, to describe abnormal states with easily detectable ferrihemoglobin contents in the blood. The early spectroscopic tests for ferrihemoglobin allowed the detection of such ferrihemoglobin contents as cause cyanosis. Following the early use of the term “ferrihemoglobinemia” to designate a pathological state, ferrihemoglobinemia should be defined as elevation of the ferrihemoglobin content of blood as causes pathological symptoms such as cyanosis or tissue hypoxia, since ferrihemoglobin does not bind oxygen reversibly as ferrohemoglobin does.
Ferrihemoglobin in Normal Blood
Manfred Kiese in Methemoglobinemia: A Comprehensive Treatise, 2019
The ferrihemoglobin produced during irradiation differed from ferrihemoglobin produced by autoxidation in the dark or by oxidation with ferricyanide. Ferrihemoglobin produced in blood in vivo or in vitro may disappear without destruction of the red cells in vivo or in vitro . It is reduced to ferrohemoglobin with full capacity for oxygen binding. Ferrihemoglobin is enzymically reduced in intact red cells when certain substrates are available. Glucose and other sugars generate NADH through the glycolytic pathway, triose phosphate and lactate being the electron donors for the reduction of NAD. During ferrihemoglobin reduction with glucose or lactate as substrates in vitro , pyruvate is found to accumulate to amounts nearly equivalent to the ferrihemoglobin reduced. A. Kajita et al. isolated three distinct fractions with ferrihemoglobin reductase activity from human red cells by chromatography on DEAE cellulose. The presence of flavin in ferrihemoglobin reductase and its possible role in the function of the enzyme await further investigation.
Some Properties of Hemoglobin Mobile (α
Published in Hemoglobin, 1985
James L. Converse, Vijay Sharma, Gwen Reiss-Rosenberg, Helen M. Ranney, Elizabeth Danish, Lynda S. Bowman, John W. Harris
A hemoglobin variant was identified as hemoglobin Mobile in which valine replaces the normal aspartic acid at β73. studies of its oxygen equilibria and of its interactions in gelation when mixed with hemoglobin S were carried out. Hemoglobin Mobile had an oxygen affinity lower than that of hemoglobin A, as observed by others. However, in mixtures with hemoglobin S, hemoglobin Mobile appeared to impair gelation or increase solubility to a slightly greater extent than did hemoglobin A. Beta73 is a known site of intermolecular interactions in polymers of hemoglobin S. Our studies suggest that the impairment of hemoglobin S polymer formation by altered intermolecular interactions is significantly less in Hb Mobile than in Hb Korle-Bu in which β73 is asparagine.
Starch-hemoglobin Induces Contraction on Isolated Rat Aortic Rings
Published in Artificial Cells, Blood Substitutes, and Biotechnology, 2004
A. Chávez-Negrete, M. V. Oropeza, M. M. Rojas, T. Villanueva, M. G. Campos
Background. Blood substitutes are being developed using molecular solutions of modified free hemoglobin; however, anaphylactic reactions, severe renal toxicity, and hypertension have been reported in experimental models and human beings. Hypertension remains as an obstacle to the clinical use of most blood substitutes. Several investigators suggest that this effect is due to the interaction between nitric oxide and hemoglobin into the endothelial cells; hence, prevention of hemoglobin extravasation would avoid vasoconstriction. The forms of hemoglobin likely to prevent extravasation include polymerized and encapsulated Hb. Another alternative and significantly less expensive approach is the hydroxyethyl starch Hb-polymer. The aim of the present study was to compare the effect of hydroxyethyl-starch-hemoglobin with that of stroma-free hemoglobin on the in vitro contractile activity of aortic rings isolated from adult male rats. Methods. The hemoglobin-based oxygen carrier was made using stroma-free hemoglobin prepared from outdated human red cells and conjugated with 10% hydroxyethyl starch 200–260 MW. The experiments were made in thoracic segments of the aortic rings incubated with hemoglobin, starch-hemoglobin or Ringer Krebs-Bicarbonate solution (RKB) during 30 min. Smooth muscle contraction with phenylephrine and subsequent inhibition of contraction with carbachol were performed before and after incubation with hemoglobin, starch-hemoglobin, or vehicle. Results. Incubation with hemoglobin and starch-hemoglobin significantly increased the contractile response to phenylephrine of aortic rings compared with RKB solution. The maximal response to carbachol was significantly decreased in the aortic rings incubated with either hemoglobin or starch-hemoglobin in comparison with the RKB-incubated tissues. There were no differences between the aortic rings incubated with either hemoglobin, or starch-hemoglobin. Conclusions. These results show that there are no differences between the effects of stroma-free hemoglobin and starch-hemoglobin on the in vitro contractile activity of aortic rings isolated from adult male rats. Our findings do not support the hypothesis that an increase in the size of the hemoglobin molecule prevents hemoglobin extravasation, and the consequent vasoconstriction due to the scavenging of nitric oxide by stroma free hemoglobin in the cellular space between endothelium and smooth muscle.
The Multiple Functions of Hemoglobin
Published in Critical Reviews in Biochemistry and Molecular Biology, 1995
Bruno Giardina, Irene Messana, Roberto Scatena, Massimo Castagnola
The aim of this review is to focus and discuss several parallel biological functions of hemoglobin besides its basic function of oxygen transport. In light of the information present in the literature the following possible physiological roles of hemoglobin are discussed: (1) hemoglobin as molecular heat transducer through its oxygenation-deoxygenation cycle, (2) hemoglobin as modulator of erythrocyte metabolism, (3) hemoglobin oxidation as an onset of erythrocyte senescence, (4) hemoglobin and its implication in genetic resistance to malaria, (5) enzymatic activities of hemoglobin and interactions with drugs, and (6) hemoglobin as source of physiological active catabolites.
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