allopurinol and Hemolysis

Hemolytic diseases are associated with elevated levels of circulating free heme that can mediate endothelial dysfunction directly via redox reactions with biomolecules or indirectly by upregulating enzymatic sources of reactive species. A key enzymatic source of these reactive species is the purine catabolizing enzyme, xanthine oxidase (XO) as the oxidation of hypoxanthine to xanthine and subsequent oxidation of xanthine to uric acid generates superoxide (O

Topics: Animals; Disease Susceptibility; Drug Discovery; Endothelium, Vascular; Gene Expression Regulation; Hemolysis; Humans; Oxidants; Oxidation-Reduction; Reactive Oxygen Species; Xanthine Oxidase

Sickle cell disease is a class of hemoglobinopathy in humans, which is the most common inherited disease in the world. Although complications of sickle cell disease start from polymerization of red blood cells during its deoxygenating phase, the oxidative stress resulting from the biological processes associated with this disease (ischaemic and hypoxic injuries, hemolysis and inflammation) has been shown to contribute to its pathophysiology. It is widely known that chronic exercise reduces oxidative stress in healthy people, mainly via improvement of antioxidant enzyme efficiency. In addition, recent studies in other diseases, as well as in sickle cell trait carriers and in a mouse model of sickle cell disease, have shown that regular physical activity could decrease oxidative stress. The purpose of this review is to summarize the role of oxidative stress in sickle cell disease and the effects of acute and chronic exercise on the pro-oxidant/antioxidant balance in sickle cell trait and sickle cell disease.

Topics: Anemia, Sickle Cell; Animals; Disease Models, Animal; Exercise; Heme; Hemoglobin, Sickle; Hemolysis; Humans; Hypoxia; Iron; Mice; NADPH Oxidases; Nitric Oxide; Oxidative Stress; Reperfusion Injury; Sickle Cell Trait; Xanthine Oxidase

Endothelial dysfunction and impaired nitric oxide bioavailability have been implicated in the pathogenesis of sickle cell anemia. Nitric oxide is a diatomic gas with a role in vascular homeostasis. Hemoglobin polymerization resulting from the HbS mutation produces erythrocyte deformation and hemolysis. Free hemoglobin, released into plasma by hemolysis scavenges on nitric oxide, and leads to reduced nitric oxide bioavailability. Pulmonary hypertension is a known consequence of sickle cell anemia. It occurs in 30-40% of patients with sickle cell anemia, and is associated with increased mortality. Several studies have implicated intravascular hemolysis, and impaired nitric oxide bioavailability in the pathogenesis of pulmonary hypertension. In this review, we summarize the mechanisms of altered nitric oxide bioavailability in sickle cell anemia and its possible role in the pathogenesis of pulmonary hypertension.

Topics: Anemia, Sickle Cell; Animals; Endothelium, Vascular; Genetic Predisposition to Disease; Hemoglobins; Hemolysis; Humans; Hypertension, Pulmonary; NADPH Oxidases; Nitric Oxide; Nitric Oxide Synthase; Oxidants; Oxidative Stress; Xanthine Oxidase

1. Sickle cell disease (SCD) is an inherited disorder of haemoglobin synthesis that is associated with significant morbidity and mortality due to sequelae of episodic vaso-occlusive events: pain crises and multiorgan damage. The microvascular responses to the initiation, progression and resolution of vaso-occlusive events are consistent with an inflammatory phenotype as suggested by activation of multiple cell types, an oxidatively stressed environment and endothelial cell dysfunction. 2. Decreased anti-oxidant defences in SCD patients and mice are accompanied by activation of enzymatic (NADPH oxidase, xanthine oxidase) and non-enzymatic (sickle haemoglobin auto-oxidation) sources of reactive oxygen species. The resultant oxidative stress leads to dysfunction/activation of arteriolar and venular endothelial cells, resulting in impaired vasomotor function and blood cell-endothelial cell adhesion. 3. Changes in substrate and cofactor availability for endothelial cell nitric oxide synthase may underlie reactive oxygen- and nitrogen-induced events that contribute to SCD-induced vasculopathy. 4. The emerging role of reactive oxygen and nitrogen species in the pathogenesis of SCD provides a platform for the development of novel agents to treat this painful and lethal disease.

Topics: Anemia, Sickle Cell; Animals; Antioxidants; Antisickling Agents; Endothelium, Vascular; Enzyme Inhibitors; Erythrocyte Aggregation; Hemoglobin, Sickle; Hemolysis; Humans; Hydroxyurea; Iron Chelating Agents; Leukocyte Rolling; NADPH Oxidases; Nitric Oxide; Nitric Oxide Synthase; Oxidative Stress; Platelet Adhesiveness; Reactive Nitrogen Species; Reactive Oxygen Species; Vasodilation; Xanthine Oxidase

Xanthine oxidase (XO) catalyzes the catabolism of hypoxanthine to xanthine and xanthine to uric acid, generating oxidants as a byproduct. Importantly, XO activity is elevated in numerous hemolytic conditions including sickle cell disease (SCD); however, the role of XO in this context has not been elucidated. Whereas long-standing dogma suggests elevated levels of XO in the vascular compartment contribute to vascular pathology via increased oxidant production, herein, we demonstrate, for the first time, that XO has an unexpected protective role during hemolysis. Using an established hemolysis model, we found that intravascular hemin challenge (40 μmol/kg) resulted in a significant increase in hemolysis and an immense (20-fold) elevation in plasma XO activity in Townes sickle cell phenotype (SS) sickle mice compared to controls. Repeating the hemin challenge model in hepatocyte-specific XO knockout mice transplanted with SS bone marrow confirmed the liver as the source of enhanced circulating XO as these mice demonstrated 100% lethality compared to 40% survival in controls. In addition, studies in murine hepatocytes (AML12) revealed hemin mediates upregulation and release of XO to the medium in a toll like receptor 4 (TLR4)-dependent manner. Furthermore, we demonstrate that XO degrades oxyhemoglobin and releases free hemin and iron in a hydrogen peroxide-dependent manner. Additional biochemical studies revealed purified XO binds free hemin to diminish the potential for deleterious hemin-related redox reactions as well as prevents platelet aggregation. In the aggregate, data herein reveals that intravascular hemin challenge induces XO release by hepatocytes through hemin-TLR4 signaling, resulting in an immense elevation of circulating XO. This increased XO activity in the vascular compartment mediates protection from intravascular hemin crisis by binding and potentially degrading hemin at the apical surface of the endothelium where XO is known to be bound and sequestered by endothelial glycosaminoglycans (GAGs).

Topics: Animals; Hemin; Hemolysis; Liver; Mice; Mice, Knockout; Oxidants; Toll-Like Receptor 4; Xanthine; Xanthine Oxidase; Xanthines

Xanthine oxidase (XO) plays a vital role in inducing hyperuricemia and increasing the level of superoxide free radicals in blood, and is proved as an important target for gout. Chrysoeriol (CHE) is a natural flavone with potent XO inhibitory activity (IC

Topics: Allopurinol; Animals; Calorimetry; Cattle; Circular Dichroism; Computational Biology; Enzyme Inhibitors; Febuxostat; Flavones; Fluorescent Dyes; Hemolysis; Kinetics; Molecular Docking Simulation; Molecular Dynamics Simulation; Protein Structure, Secondary; Rabbits; Spectrometry, Fluorescence; Spectrophotometry, Ultraviolet; Time Factors; Xanthine Oxidase

Chronic hemolysis is a hallmark of sickle cell disease (SCD) and a driver of vasculopathy; however, the mechanisms contributing to hemolysis remain incompletely understood. Although XO (xanthine oxidase) activity has been shown to be elevated in SCD, its role remains unknown. XO binds endothelium and generates oxidants as a byproduct of hypoxanthine and xanthine catabolism. We hypothesized that XO inhibition decreases oxidant production leading to less hemolysis. Approach and Results: Wild-type mice were bone marrow transplanted with control (AA) or sickle (SS) Townes bone marrow. After 12 weeks, mice were treated with 10 mg/kg per day of febuxostat (Uloric), Food and Drug Administration-approved XO inhibitor, for 10 weeks. Hematologic analysis demonstrated increased hematocrit, cellular hemoglobin, and red blood cells, with no change in reticulocyte percentage. Significant decreases in cell-free hemoglobin and increases in haptoglobin suggest XO inhibition decreased hemolysis. Myographic studies demonstrated improved pulmonary vascular dilation and blunted constriction, indicating improved pulmonary vasoreactivity, whereas pulmonary pressure and cardiac function were unaffected. The role of hepatic XO in SCD was evaluated by bone marrow transplanting hepatocyte-specific XO knockout mice with SS Townes bone marrow. However, hepatocyte-specific XO knockout, which results in >50% diminution in circulating XO, did not affect hemolysis levels or vascular function, suggesting hepatocyte-derived elevation of circulating XO is not the driver of hemolysis in SCD.. Ten weeks of febuxostat treatment significantly decreased hemolysis and improved pulmonary vasoreactivity in a mouse model of SCD. Although hepatic XO accounts for >50% of circulating XO, it is not the source of XO driving hemolysis in SCD.

Topics: Anemia, Sickle Cell; Animals; Disease Models, Animal; Enzyme Inhibitors; Erythrocytes; Febuxostat; Hemodynamics; Hemolysis; Liver; Male; Mice, Inbred C57BL; Mice, Knockout; Pulmonary Artery; Ventricular Function; Xanthine Oxidase

Topics: Anti-Bacterial Agents; Anti-Infective Agents; Green Chemistry Technology; Hemolysis; Hot Temperature; Hydrogen-Ion Concentration; Metal Nanoparticles; Microbial Sensitivity Tests; Microscopy, Electron, Transmission; Nanomedicine; Particle Size; Plant Extracts; Plant Leaves; Plant Roots; Ricinus; Silver; Spectrophotometry, Ultraviolet; Spectroscopy, Fourier Transform Infrared; Temperature; Urease; X-Ray Diffraction; Xanthine Oxidase

Snakebites have been recognized as a neglected public health problem in several tropical and subtropical countries. Bothrops snakebites frequently complicate with acute kidney injury (AKI) with relevant morbidity and mortality. To date, the only treatment available for Bothrops envenomation is the intravenous administration of antivenom despite its several limitations. Therefore, the study of novel therapies in Bothrops envenomation is compelling. The aim of this study was to evaluate the protective effect of Allopurinol (Allo) in an experimental model of Bothrops jararaca venom (BJ)-associated AKI. Five groups of Wistar rats were studied: Sham, Allo, BJ, BJ+Allo, BJ+ipAllo. BJ (0.25 mg/kg) was intravenously injected during 40'. Saline at same dose and infusion rate was administered to Sham and Allo groups. Allo and BJ+Allo groups received Allo (300 mg/L) in the drinking water 7 days prior to Saline or BJ infusion respectively. BJ+ipAllo rats received intraperitoneal Allo (25 mg/Kg) 40' after BJ infusion. BJ rats showed markedly reduced glomerular filtration rate (GFR, inulin clearance) associated with intense renal vasoconstriction, hemolysis, hemoglobinuria, reduced glutathione and increased systemic and renal markers of nitro-oxidative stress (Nitrotyrosine). Allo ameliorated GFR, renal blood flow (RBF), renal vascular resistance and arterial lactate levels. In addition, Allo was associated with increased serum glutathione as well as reduced levels of plasma and renal Nitrotyrosine. Our data show that Allo attenuated BJ-associated AKI, reduced oxidative stress, improved renal hemodynamics and organ perfusion. It might represent a novel adjuvant approach for Bothrops envenomation, a new use for an old and widely available drug.

Topics: Acute Kidney Injury; Allopurinol; Animals; Antioxidants; Bothrops; Crotalid Venoms; Glomerular Filtration Rate; Glutathione; Hemolysis; Kidney; Lactic Acid; Male; Oxidative Stress; Rats, Wistar; Tyrosine

Human red blood cells (RBCs) are emerging as a highly biocompatible microparticulate drug delivery system. So far, drugs have commonly been loaded into freshly isolated RBCs using rather disruptive methods based on hypotonic shock, and assessment of damage was restricted to hemolysis. Here, we investigated loading of RBCs from blood bank units with enzymes of various molecular weights using hypotonic dialysis (HD), pretreatment with chlorpromazine (CPZ) and fusion with liposomes. The latter two techniques have received little attention in RBC loading so far. Along with loading efficiency, all methods were tested for the induction of side effects. Very importantly, next to hemolysis, we also addressed morphological changes and phosphatidyl serine (PS) exposure, which has been recognized as a critical parameter associated with premature RBC removal and induction of transfusion-related pathologies. The efficiency of loading using hypotonic dialysis decreased with the molecular weight of the enzyme. For liposomes and chlorpromazine, loading efficiencies were higher and independent of enzyme molecular weights. While hypotonic dialysis always induced a high degree of hemolysis, irreversible modifications in the morphology of the cells and PS exposure, the side effects that were induced by loading using CPZ and liposomes were limited. In particular, PS exposure, although high immediately after treatment, returned to physiological levels after recovery. Retention and deformability studies using a spleen-mimicking device showed that RBCs treated with CPZ and liposomes behave like physiological RBCs, while HD led to very fragile and poorly deformable RBCs.

Topics: Antipsychotic Agents; beta-Galactosidase; Chlorpromazine; Dialysis; Drug Carriers; Erythrocytes; Fluorescent Dyes; Hemolysis; Horseradish Peroxidase; Humans; Hypotonic Solutions; Phosphatidylserines; Rhodamines; Xanthine Oxidase

Spectrin is the backbone of the erythroid cytoskeleton; sph/sph mice have severe hereditary spherocytosis (HS) because of a mutation in the murine erythroid alpha-spectrin gene. sph/sph mice have a high incidence of thrombosis and infarction in multiple tissues, suggesting significant vascular dysfunction. In the current study, we provide evidence for both pulmonary and systemic vascular dysfunction in sph/sph mice. We found increased levels of soluble cell adhesion molecules in sph/sph mice, suggesting activation of the vascular endothelium. We hypothesized that plasma hemoglobin released by intravascular hemolysis initiates endothelial injury through nitric oxide (NO) scavenging and oxidative damage. Likewise, electron paramagnetic resonance spectroscopy showed that plasma hemoglobin is much greater in sph/sph mice. Moreover, plasma from sph/sph mice had significantly higher oxidative potential. Finally, xanthine oxidase, a potent superoxide generator, is decreased in subpopulations of liver hepatocytes and increased on liver endothelium in sph/sph mice. These results indicate that vasoregulation is abnormal, and NO-based vasoregulatory mechanisms particularly impaired, in sph/sph mice. Together, these data indicate that sph/sph mice with severe HS have increased plasma hemoglobin and NO scavenging capacity, likely contributing to aberrant vasoregulation and initiating oxidative damage.

Topics: Animals; Disease Models, Animal; Hemoglobins; Hemolysis; Hypertension, Pulmonary; Liver; Mice; Mice, Mutant Strains; Nitric Oxide; Spectrin; Spherocytosis, Hereditary; Vasodilation; Xanthine Oxidase

Cordyceps (summer-grass, winter-worm), one of the most valued traditional Chinese medicines, is used commonly for the replenishment of body health. It consists of the dried fungus Cordyceps sinensis growing on caterpillar larvae. For medication, the fruiting body (fungus) and the worm (caterpillar) are used together. However, the pharmacological efficiency and the main constituents of the individual parts have not been determined. In the present study the water extracts from the fruiting body and worm of natural Cordyceps were analyzed for their content of nucleosides and polysaccharides; the results showed that the worm had chemical composition similar to the fruiting body. In addition, both the fruiting body and worm of Cordyceps showed similar potency in their anti-oxidation activities in the xanthine oxidase assay, the induction of hemolysis assay and the lipid-peroxidation assay. These results suggest that the function of the worm in Cordyceps is to provide a growth medium for the fruiting body, and that eventually, the worm is totally invaded by C. sinensis mycelia.

Topics: Animals; Antioxidants; Cordyceps; Dose-Response Relationship, Drug; Drugs, Chinese Herbal; Erythrocytes; Female; Fruit; Hemolysis; Inhibitory Concentration 50; Lepidoptera; Lipid Peroxidation; Male; Microsomes, Liver; Phytotherapy; Plant Extracts; Rabbits; Rats; Rats, Wistar; Xanthine Oxidase

Cordyceps, one of the well-known traditional Chinese medicines, consists of the dried fungus Cordyceps sinensis growing on the larva of the caterpillar. It is commonly used for the replenishment of body health. One of the known pharmacological effects is its anti-oxidation activity. However, there is a great variation of the quality in different sources of Cordyceps. Here, the water extracts of various sources of natural C. sinensis and cultured Cordyceps mycelia were analyzed for their anti-oxidation activity by using three different assay methods such as the xanthine oxidase assay, the induction of hemolysis assay and the lipid peroxidation assay. The results showed that Cordyceps, in general, possesses a strong anti-oxidation activity in all assays tested. However, both natural and cultured Cordyceps showed the lowest inhibition in the lipid peroxidation when compared with the other two assay methods. The cultured Cordyceps mycelia had equally strong anti-oxidation activity as compared to the natural Cordyceps. Besides, the anti-oxidation activities were increased to 10-30 folds in the partially purified polysaccharide fractions from the cultured Cordyceps mycelia, which suggested that the activity could be derived partly from Cordyceps polysaccharides.

Topics: Animals; Antioxidants; Drugs, Chinese Herbal; Erythrocytes; Hemolysis; Hypocreales; Lepidoptera; Lipid Peroxidation; Male; Medicine, Chinese Traditional; Microsomes, Liver; Mycelium; Polysaccharides; Rabbits; Rats; Rats, Wistar; Superoxides; Xanthine Oxidase

A biphenyl compound, 3,4,3',4'-tetrahydroxy-5,5'-diisopropyl-2,2'-dimethylbiphenyl (1), and a flavonoid, eriodicytol (2), were isolated as antioxidative components from the leaves of Thymus vulgaris by bioassay-directed fractionation. These compounds inhibited superoxide anion production in the xanthine/xanthine oxidase system. Mitochondrial and microsomal lipid peroxidation induced by Fe(III)-ADP/NADH or Fe(III)-ADP/NADPH were also inhibited by these compounds. Compound 1 is an extremely potent antioxidant; complete inhibition was observed at 1 microM against both microsomal and mitochondrial peroxidation. Furthermore, compound 1 protected red cells against oxidative hemolysis. These phenolic compounds were shown to be effective to protect biological systems against various oxidative stresses.

Topics: Animals; Antioxidants; Hemolysis; Humans; Lipid Peroxidation; Magnoliopsida; Male; Microsomes, Liver; Mitochondria, Liver; Phenols; Plant Extracts; Plant Leaves; Rats; Rats, Wistar; Superoxides; Xanthine; Xanthine Oxidase; Xanthines

Although reactive oxygen metabolites may play a pivotal role in mediating microvascular reperfusion injury, the source of these radicals is still a matter of controversy. With the use of spectrophotometry and intravital microscopy we studied the role of xanthine oxidase and superoxide radicals in portal triad crossclamping-induced microvascular injury in rats. After 20 min of global hepatic ischemia and splanchnic vascular congestion, followed by 40 min of reperfusion (n = 8), xanthine oxidase activities in hepatic venous (26.9 +/- 4.7 nmol/ml x min) and systemic arterial blood (16.3 +/- 2.5 nmol/ml x min) were found significantly (p < .01) increased when compared with sham-operated controls (6.8 +/- 0.9 and 6.0 +/- 0.8 nmol/ml x min, n = 8). The increase of xanthine oxidase activity was accompanied by oxygen radical-mediated intravascular hemolysis. Intravital microscopy (n = 6) revealed accumulation of leukocytes within the postischemic hepatic microvasculature with stasis in sinusoids (75.9 +/- 8.9 per liver lobule) and adherence to the endothelial lining of postsinusoidal venules (534.7 +/- 125.3 per mm2 endothelial surface). Concomitantly, compromised microvascular reperfusion was characterized by perfusion deficits of individual sinusoids (25.6 +/- 4.0% nonperfused sinusoids). The xanthine oxidase inhibitor allopurinol (50 mg/kg b.wt., orally, n = 6) and the radical scavenger superoxide dismutase (60000 IU/kg b.wt., IV, n = 6) effectively (p < .01) inhibited both sinusoidal leukostasis (16.1 +/- 2.6 and 32.1 +/- 3.1 cells/lobule) and venular leukocyte adherence (247.6 +/- 7.9 and 205.0 +/- 38.0 cells/mm2), and, hence, reduced microcirculatory deteriorations, indicated by the attenuation of sinusoidal perfusion failure (2.8 +/- 0.8 and 9.0 +/- 3.1%). Our results support the hypothesis that portal triad crossclamping-induced microvascular reperfusion injury is triggered by superoxide radicals derived from the xanthine oxidase system.

Topics: Allopurinol; Animals; Constriction; Enzyme Inhibitors; Free Radicals; Hemolysis; Hepatic Artery; Liver; Microcirculation; Portal Vein; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Superoxide Dismutase; Superoxides; Xanthine Oxidase

Although cigarette smoking has been identified as a major risk factor for cardiovascular diseases, the underlying pathomechanism is largely unknown. Using a dorsal skinfold chamber model in Syrian golden hamsters for intravital microscopy on striated muscle microcirculation, we investigated whether cigarette smoke (CS) affects the adhesion of circulating leukocytes to the endothelium, a constant feature of early atherogenesis and a hallmark of ischemia-reperfusion injury. Awake hamsters were exposed for 5 min to the mainstream smoke of one cigarette (2R1 research cigarette), inducing nicotine, cotinine, and carboxyhemoglobin plasma levels comparable to levels found in human smokers. In control animals (n = 7), CS exposure elicited the rolling and subsequent adhesion of fluorescently stained leukocytes to the endothelium of arterioles and postcapillary venules. Leukocyte/endothelium interaction was preceded by an early rise in xanthine oxidase activity and intravascular hemolysis. Leukocyte adhesion and xanthine oxidase (XO) activation were significantly attenuated in hamsters pretreated with superoxide dismutase (5 mg/kg, 10 min prior to CS, n = 7), suggesting a key role of superoxide in this event. These in vivo results suggest a novel pathomechanism of CS-induced cardiovascular pathology.

Topics: Animals; Cell Adhesion; Cricetinae; Endothelium, Vascular; Free Radicals; Hemolysis; Leukocytes; Mesocricetus; Microcirculation; Smoking; Superoxide Dismutase; Xanthine Oxidase

Using a hypoxanthine-xanthine oxidase (HX-XOD) reaction system, the effect of vitamin E (VE) on oxidative membrane injury was studied by the impedance method. Both VE-sufficient and VE-deficient erythrocytes showed an elevation of low frequency permittivity in the early phase of reaction. In the later phase of reaction, VE-sufficient erythrocytes showed a sustained elevation in permittivity, while VE-deficient erythrocytes showed a decrease in permittivity with time. These changes consisted with the process of hemolysis in the HX-XOD system. The similarity of early phase change between VE-sufficient and VE-deficient erythrocytes indicates that the HX-XOD system exerted a similar effect on both erythrocytes in the early phase. The difference in changes of later phase between the two types of erythrocytes suggests that VE suppressed the reduction in permittivity. When the results were analyzed by the Pauly-Schwan's theory based on the assumption that erythrocytes are spherical, the product of VE-deficient or VE-sufficient erythrocyte size (R) and membrane capacity (Cm) showed a change similar to that in permittivity.

Topics: Algorithms; Animals; Electric Conductivity; Hemolysis; Male; Oxidation-Reduction; Rats; Rats, Inbred Strains; Vitamin E; Vitamin E Deficiency; Xanthine Oxidase

The oxidation of vitamin E-deficient rat red blood cells (RBCs) induced by the hypoxanthine-xanthine oxidase (HX-XOD) system has been performed in an aqueous suspension. The generation of chemiluminescence and the accumulation of thiobarbituric acid-reactive substances (TBARS) were observed initially and were followed by hemolysis. Interestingly, the total counts of chemiluminescence were closely related to the amount of TBARS. The predominant change of membrane proteins induced by the reaction was the depletion of spectrin bands in gel electrophoresis. When RBC ghosts were oxidized with HX-XOD, the sulfhydryl (SH) groups of membrane proteins decreased at an early stage of the incubation, which was coincident with the above protein alteration. Membrane alpha-tocopherol suppressed not only the formation of TBARS but also chemiluminescence and hemolysis; nevertheless, it did not inhibit the protein damage and the loss of SH groups. Moreover, it was concluded that the chemiluminescence observed during the oxidation of RBC membranes was associated mainly with the peroxidation of lipids and only to a minor extent with the oxidation of proteins.

Topics: Animals; Erythrocyte Membrane; Hemolysis; Hydrogen Peroxide; Lipid Peroxidation; Luminescent Measurements; Male; Membrane Lipids; Membrane Proteins; Oxidation-Reduction; Rats; Rats, Inbred Strains; Spectrin; Sulfhydryl Compounds; Superoxides; Thiobarbiturates; Vitamin E; Vitamin E Deficiency; Xanthine; Xanthine Oxidase; Xanthines

This report is concerned with the experience gained with two 2,8-dihydroxyadenine (2,8-DHA) stone patients. When adenine phosphoribosyltransferase (APRT) deficiency is suspected, the risk of stone formation can be detected at an early stage from the crystalline urinary sediment. Infrared spectroscopic analysis of the crystals or of a urinary stone, if present, will confirm the diagnosis. Determination of the APRT activity will facilitate quantification of the enzyme deficiency and elucidation of the hereditary history. 2,8-DHA excretion in the 24-hour urine and its circadian rhythm were determined at 3-hour intervals using a new method of high performance liquid chromatography determination. This method also provides a means of monitoring the effectiveness of allopurinol therapy.

Topics: Adenine; Adenine Phosphoribosyltransferase; Adult; Allopurinol; Chemistry, Physical; Child; Circadian Rhythm; Crystallization; Erythrocytes; Female; Hemolysis; Humans; Kidney Calculi; Male; Time Factors

Topics: Animals; Catalase; Erythrocyte Membrane; Hemolysis; Kinetics; Luminescent Measurements; Male; Rats; Rats, Inbred Strains; Reference Values; Vitamin E Deficiency; Xanthine Oxidase

Topics: Animals; Erythrocytes; Free Radicals; Hemolysis; Lipid Peroxides; Luminescent Measurements; Male; Membrane Lipids; Rats; Rats, Inbred Strains; Superoxides; Thiobarbiturates; Vitamin E; Vitamin E Deficiency; Xanthine Oxidase

A procedure to induce hemolysis by the hypoxanthine-xanthine oxidase reaction was developed and applied to vitamin E deficient red blood cells (RBCs) in rats. The reaction system was as follows: 0.16 mM hypoxanthine, 0.05 U/ml xanthine oxidase in 2.5% RBC suspensions with an isotonic buffer (pH 7.4) containing 10 mM phosphate buffer and 125 mM saline (277 mOsm). Hemolysis was observed to depend on the vitamin E concentrations in the RBCs. Hemolysis was inhibited by catalase but not by SOD. After the reaction with vitamin E deficient RBCs, an increase in TBARS in the aqueous phase of the reaction mixture was observed. This accompanied the increase in fluorescent substances in the lipid extracts, in association with a significant decrease in the PE and PS of the RBCs, and a decrease in arachidonic acid in membrane lipids. The above changes were almost completely inhibited by tocopherol incorporated into vitamin E deficient RBCs.

Topics: Animals; Erythrocytes; Hemolysis; Hydrogen Peroxide; Male; Membrane Lipids; Rats; Rats, Inbred Strains; Superoxides; Vitamin E Deficiency; Xanthine Oxidase

Topics: Allopurinol; Azathioprine; Chemical and Drug Induced Liver Injury; Drug Synergism; Drug Therapy, Combination; Graft Rejection; Hemolysis; Humans; Kidney Transplantation; Male; Middle Aged; Pancreatitis; Pancytopenia; Postoperative Complications; Uric Acid

Topics: Acetaldehyde; Animals; Cattle; Ceruloplasmin; Erythrocytes; Hemolysis; Humans; Male; Rats; Xanthine Oxidase

A very rapid hemolysis was found to be caused by active oxygen species produced by a hypoxanthine-xanthine oxidase system with very low concentrations of hypoxanthine. The addition of superoxide dismutase or catalase inhibited the hemolysis, indicating that O2- and H2O2 participate in this system. The extent of erythrocyte hemolysis was found to depend on the sex of the human donor. The change in phospholipid composition before and after hemolysis in human erythrocytes from donors of each sex was compared by thin layer chromatography. A significant decrease in phosphatidylethanolamine content and a concomitant increase in altered phospholipid fraction were observed in erythrocytes from male donors, suggesting that these erythrocytes were easily attacked by active oxygen species to produce modified phosphatidylethanolamine.

Topics: Adult; Catalase; Erythrocyte Membrane; Erythrocytes; Female; Hemolysis; Humans; Hypoxanthines; In Vitro Techniques; Male; Membrane Lipids; Oxidation-Reduction; Phospholipids; Sex Factors; Superoxide Dismutase; Xanthine Oxidase

Xanthine oxidase, acting on acetaldehyde under aerobic conditions, produces a flux of O2- and H2O2 which attacks artificial liposomes and washed human erythrocytes. The liposomes were peroxidized and the erythrocytes suffered oxidation of hemoglobin followed by lysis. The oxidation of hemoglobin followed by lysis. The oxidation of hemoglobin, within the exposed erythrocytes, could be largely prevented by prior conversion to carbon monoxyhemoglobin, without preventing lysis. Hemolysis thus appeared to be a consequence of direct oxidative attack on the cell stroma. The enzyme-generated flux of O2- and of H2O2 also inactivated the xanthine oxidase. Superoxide dismutase or catalase, present in the suspending medium, protected the liposomes against peroxidation, the erythrocytes against lysis, and the xanthine oxidase against inactivation. Scavengers of O2('deltag), such as histidine or 2,5-dimethylfuran, which do not react with O2- or H2O2, also prevented peroxidation of liposomes and lysis of erythrocytes when present at low concentrations. In contrast a scavenger of OH-, such as mannitol was ineffective at low concentrations and provided significant protection only at much higher concentrations. It is proposed that O2- and H2O2 cooperated in producing OH- and O2('deltag), which were the proximate causes of lipid peroxidation and of hemolysis.

Topics: Adult; Carbon Monoxide; Erythrocytes; Hemolysis; Humans; Hydrogen Peroxide; Liposomes; Male; Oxygen; Superoxides; Xanthine Oxidase

Topics: Animals; Erythrocytes; Glutathione Reductase; Hemolysis; Osmotic Fragility; Rats; Riboflavin Deficiency; Xanthine Oxidase

Topics: Animals; Erythrocytes; Hemolysis; Phenylhydrazines; Rats; Superoxide Dismutase; Xanthine Oxidase

Topics: Alloxan; Animals; Barbiturates; Catalase; Cell Membrane; Cytochrome c Group; Electron Spin Resonance Spectroscopy; Erythrocytes; Hemolysis; Hydrogen Peroxide; Hydroquinones; In Vitro Techniques; Lipid Metabolism; Male; Methemoglobin; Oxidation-Reduction; Oxygen; Rats; Superoxide Dismutase; Time Factors; Vitamin E Deficiency; Xanthine Oxidase; Xanthines

Topics: Allopurinol; Amenorrhea; Busulfan; Chlorambucil; Chronic Disease; Drug Eruptions; Female; Hemolysis; Humans; Leukemia, Lymphoid; Leukemia, Myeloid; Leukocytosis; Lymphocytosis; Prednisolone; Pulmonary Fibrosis; Splenectomy; Vincristine

Topics: Adenine; Adult; Allopurinol; Animals; Blood Glucose; Carbon Radioisotopes; Diphosphates; Erythrocytes; Guanine; Hemolysis; Humans; Hypoxanthines; Inosine; Purines; Ribose; Species Specificity; Swine; Time Factors

Topics: Administration, Oral; Adult; Allopurinol; Diphosphates; Erythrocytes; Female; Gout; Hemolysis; Humans; In Vitro Techniques; Male; Middle Aged; Nucleotides; Purines; Pyrazoles; Pyrimidines; Ribose; Uric Acid; Xanthine Oxidase

Topics: Adult; Aged; Allopurinol; Anemia, Hypochromic; Blood Transfusion; Deferoxamine; Diet; Erythrocytes; Feces; Female; Heme; Hemochromatosis; Hemolysis; Hemosiderosis; Humans; Injections, Intramuscular; Injections, Intravenous; Intestinal Absorption; Iron; Iron Chelating Agents; Iron Isotopes; Iron-Dextran Complex; Kidney; Male; Methods; Middle Aged; Nicotinic Acids; Sex Factors; Time Factors; Xanthine Oxidase