The Experts below are selected from a list of 108 Experts worldwide ranked by ideXlab platform
Radu Silaghi-dumitrescu - One of the best experts on this subject based on the ideXlab platform.
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EPR detection of sulfanyl radical during Sulfhemoglobin formation - Influence of catalase.
Free Radical Biology and Medicine, 2019Co-Authors: Cristina Pușcaș, Sorin Dorneanu, Radu Silaghi-dumitrescuAbstract:Abstract Hemoglobin in its ferryl form oxidizes hydrogen sulfide and is transformed to Sulfhemoglobin, where the sulfur is inserted covalently at the heme edge. Shown here is evidence that—as previously proposed by others—this process involves oxidation of hydrogen sulfide to a sulfanyl radical detectable by spin-trapping in electron paramagnetic resonance (EPR) spectroscopy. The yields and rates of formation of Sulfhemoglobin as well as of the sulfanyl radical are affected by the same factors that affect the reactivity of hemoglobin ferryl, in bovine hemoglobin and in phytoglobins as well. A freely-diffusing sulfanyl radical is thus proposed to be involved in Sulfhemoglobin formation. Catalase is shown to accelerate this process due to a previously described hydrogen sulfide oxidase activity, within which EPR evidence for sulfanyl generation is shown here for the first time. The reaction of preformed ferryl with hydrogen sulfide—in absence of hydrogen peroxide—is studied by stopped-flow at several pH values and explained in light of reactivity and redox potential control.
Cristina Pușcaș - One of the best experts on this subject based on the ideXlab platform.
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EPR detection of sulfanyl radical during Sulfhemoglobin formation - Influence of catalase.
Free Radical Biology and Medicine, 2019Co-Authors: Cristina Pușcaș, Sorin Dorneanu, Radu Silaghi-dumitrescuAbstract:Abstract Hemoglobin in its ferryl form oxidizes hydrogen sulfide and is transformed to Sulfhemoglobin, where the sulfur is inserted covalently at the heme edge. Shown here is evidence that—as previously proposed by others—this process involves oxidation of hydrogen sulfide to a sulfanyl radical detectable by spin-trapping in electron paramagnetic resonance (EPR) spectroscopy. The yields and rates of formation of Sulfhemoglobin as well as of the sulfanyl radical are affected by the same factors that affect the reactivity of hemoglobin ferryl, in bovine hemoglobin and in phytoglobins as well. A freely-diffusing sulfanyl radical is thus proposed to be involved in Sulfhemoglobin formation. Catalase is shown to accelerate this process due to a previously described hydrogen sulfide oxidase activity, within which EPR evidence for sulfanyl generation is shown here for the first time. The reaction of preformed ferryl with hydrogen sulfide—in absence of hydrogen peroxide—is studied by stopped-flow at several pH values and explained in light of reactivity and redox potential control.
Sorin Dorneanu - One of the best experts on this subject based on the ideXlab platform.
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EPR detection of sulfanyl radical during Sulfhemoglobin formation - Influence of catalase.
Free Radical Biology and Medicine, 2019Co-Authors: Cristina Pușcaș, Sorin Dorneanu, Radu Silaghi-dumitrescuAbstract:Abstract Hemoglobin in its ferryl form oxidizes hydrogen sulfide and is transformed to Sulfhemoglobin, where the sulfur is inserted covalently at the heme edge. Shown here is evidence that—as previously proposed by others—this process involves oxidation of hydrogen sulfide to a sulfanyl radical detectable by spin-trapping in electron paramagnetic resonance (EPR) spectroscopy. The yields and rates of formation of Sulfhemoglobin as well as of the sulfanyl radical are affected by the same factors that affect the reactivity of hemoglobin ferryl, in bovine hemoglobin and in phytoglobins as well. A freely-diffusing sulfanyl radical is thus proposed to be involved in Sulfhemoglobin formation. Catalase is shown to accelerate this process due to a previously described hydrogen sulfide oxidase activity, within which EPR evidence for sulfanyl generation is shown here for the first time. The reaction of preformed ferryl with hydrogen sulfide—in absence of hydrogen peroxide—is studied by stopped-flow at several pH values and explained in light of reactivity and redox potential control.
Darrell L - One of the best experts on this subject based on the ideXlab platform.
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Microvessel mean transit time and blood flow velocity of Sulfhemoglobin-RBC
2016Co-Authors: C H Baker, E T Sutton, L. Davis, Carleton H, Darrell LAbstract:DAVIS. Microvessel mean transit time and blood flow velocity of Sulfhemoglobin-RBC. Am. J. Physiol. 238 (Heart Circ. Phys-iol. 7): H745-H749, 1980.-An indicator dilution technique is described for obtaining time-concentration curves subsequent to bolus injections of Sulfhemoglobin red blood cells (SH-RBC), which have a deep greenish-brown color (absorption peak 620 nm vs. 542 and 564 nm for normal red cells). The series- and parallel-coupled microvessels of cat mesentery were studied. This is accomplished by means of video microscopy with a two-window intensity-sensitive video sampler system. The relation-ship between SH-RBC concentration in blood and optical meas-urement is linear. Blood flow velocities were calculated from the difference in mean transit times between two points along a vessel. When this technique is used in association with the previously reported method for determining time-concentratio
Gladimir V G Baranoski - One of the best experts on this subject based on the ideXlab platform.
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Three-wavelength method for the optical differentiation of methemoglobin and Sulfhemoglobin in oxygenated blood
2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017Co-Authors: Spencer R. Van Leeuwen, Gladimir V G Baranoski, Bradley W. KimmelAbstract:Methemoglobinemia and Sulfhemoglobinemia are rare, but potentially life threatening, diseases that refer to an abnormal amount of methemoglobin or Sulfhemoglobin in the blood, respectively. Unfortunately, blood samples containing abnormal quantities of methemoglobin or Sulfhemoglobin have similar spectral characteristics. This makes it difficult to optically differentiate them and, hence, difficult to diagnose a patient with either disease. However, performing treatments for one of the diseases without a correct diagnosis can introduce increased risk to the patient. In this paper, we propose a method for differentiating the presence of methemoglobin and Sulfhemoglobin in blood, under several conditions, using reflectance values measured at three wavelengths. In order to validate our method, we perform in silico experiments considering various levels of methemoglobin and Sulfhemoglobin. These experiments employ a cell-based light interaction model, known as CLBlood, which accounts for the orientation and distribution of red blood cells. We then discuss the reflectance curves produced by the experiments and evaluate the efficacy of our method. In particular, we consider various experimental conditions by modifying the flow rate, hemolysis level and incident light direction.
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On the noninvasive optical monitoring and differentiation of methemoglobinemia and Sulfhemoglobinemia
Journal of Biomedical Optics, 2012Co-Authors: Gladimir V G Baranoski, Tenn F. Chen, Bradley W. Kimmel, Erik Miranda, Daniel YimAbstract:There are several pathologies whose study and diagnosis is impaired by a relatively small number of documented cases. A practical approach to overcome this obstacle and advance the research in this area consists in employing computer simulations to perform controlled in silico experiments. The results of these experiments, in turn, may be incorporated in the design of differential protocols for these pathologies. Accordingly, in this paper, we investigate the spectral responses of human skin affected by the presence of abnormal amounts of two dysfunctional hemoglobins, methemoglobin and Sulfhemoglobin, which are associated with two life-threatening medical conditions, methemoglobinemia and Sulfhemoglobinemia, respectively. We analyze the results of our in silico experiments and discuss their potential applications to the development of more effective noninvasive monitoring and differentiation procedures for these medical conditions.
