A Combined Protective Dose of Angelica archangelica and Ginkgo biloba Restores Normal Functional Hemoglobin Derivative Levels in Rabbits after Oxidative Stress Induced by Gallium-68

Oxidative stress is a physiological imbalance between the production of reactive oxygen species (ROS) and the body’s ability to detoxify these products. Oxidative stress induced by ionizing radiation is one of the late biological effects of radiation. The aim of this study was to assess the protective role of Angelica archangelica and Ginkgo biloba extracts, which are commonly used as antioxidants in counteracting effects related to functional and non-functional hemoglobin derivative concentrations, as well as the rate of hemoglobin autoxidation before exposing rabbits to ionizing radiation. The experimental design included four groups of rabbits: a control group that did not receive gallium or antioxidants; Group 1, which received 68Ga isotope as a source of ionizing radiation with no prior treatment; Groups 2 and 3, which received A. archangelica and G. biloba root powder water extracts, respectively, for seven days prior to irradiation; and Group 4, which received a combined dose of both antioxidants, A. archangelica and G. biloba, prior to irradiation, with the same dose, time, and duration as used in Groups 2 and 3. The results demonstrate that both antioxidants had the ability to counteract oxidative stress induced by ionizing radiation, as well as to reduce the hemoglobin autoxidation rate. A synergistic effect was revealed when using a combined dose of both antioxidants at the same concentrations, times, and durations. A lower rate of free radical formation was also recorded, reflected by a reduction in superoxide dismutase (SOD) and glutathione peroxidase activity. The data here presented support the radioprotective role of both investigated antioxidants.

Laboratory Assessment of Oxygenation in Methemoglobinemia

Background: This case conference reviews laboratory methods for assessing oxygenation status: arterial blood gases, pulse oximetry, and CO-oximetry. Caveats of these measurements are discussed in the context of two methemoglobinemia cases. Cases: Case 1 is a woman who presented with increased shortness of breath, productive cough, chest pain, nausea, fever, and cyanosis. CO-oximetry indicated a carboxyhemoglobin (COHb) fraction of 24.9%. She was unresponsive to O2 therapy, and no source of carbon monoxide could be noted. Case 2 is a man who presented with syncope, chest tightness, and signs of cyanosis. His arterial blood was dark brown, and CO-oximetry showed a methemoglobin (MetHb) fraction of 23%. Issues: Oxygen saturation (So2) can be measured by three approaches that are often used interchangeably, although the measured systems are quite different. Pulse oximetry is a noninvasive, spectrophotometric method to determine arterial oxygen saturation (SaO2). CO-oximetry is a more complex and reliable method that measures the concentration of hemoglobin derivatives in the blood from which various quantities such as hemoglobin derivative fractions, total hemoglobin, and saturation are calculated. Blood gas instruments calculate the estimated O2 saturation from empirical equations using pH and Po2 values. In most patients, the results from these methods will be virtually identical, but in cases of increased dyshemoglobin fractions, including methemoglobinemia, it is crucial that the distinctions and limitations of these methods be understood. Conclusions: So2 calculated from pH and Po2 should be interpreted with caution as the algorithms used assume normal O2 affinity, normal 2,3-diphosphoglycerate concentrations, and no dyshemoglobins or hemoglobinopathies. CO-oximeter reports should include the dyshemoglobin fractions in addition to the oxyhemoglobin fraction. In cases of increased MetHb fraction, pulse oximeter values trend toward 85%, underestimating the actual oxygen saturation. Hemoglobin M variants may yield normal MetHb and increased COHb or sulfhemoglobin fractions measured by CO-oximetry.