Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Antioxidant defence was investigated in red blood cells (RBC) in 56 patients with 3 different haemoblastoses: polycythemia vera (PV), chronic myelogenous leukaemia (CML), chronic lymphoid leukemia (CLL) with and without anaemia, in 12 iron deficiency anaemia (A) patients and 50 healthy persons. The activities were determined of the following antioxidant enzymes: glucose-6-phosphate dehydrogenase (G6PD), glutathione reductase (GSSG-R), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT) and MDA levels. Antioxidant defence is decreased and the level of lipid peroxidation are increased in RBC in all patients (PV, CML, CLL, A). Different changes were detected in the antioxidative defence between normal red blood cells and those formed from leukaemic cells clone. In normal RBC in anaemia (CLL, A) opposite deviation of G6PD and GSSG-R activities was observed. In RBC formed from leukaemic cell clone (PV, CML), a simultaneous significant increase in G6PD and GSSG-R activities was found, which indicated activisation of pentose phosphate pathways (PPP) in these pathologies; in anaemia they function less effectively.
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PMID:Anaemia and antioxidant defence of the red blood cells. 1021 69

Nitrobenzene (NB) human cancer studies have not been reported, but animals studies have. Three rodent strains inhaling NB produce cancer at eight sites. B6C3F1 mice respond with mammary gland malignant tumors and male lung and thyroid benign tumors, F344/N male rats respond with liver malignant tumors and thyroid and kidney benign tumors, while females respond with endometrial polyps. Male Sprague-Dawley rats (CD strain) respond with liver benign tumors. NB is oxidized to various phenolic metabolites, while also being reduced in the cecum and systemically in the microsomes to nitrosobenzene (NOB), phenylhydroxylamine (PH), related free radicals, and aniline (AN). Based on structural and mechanistic similarities, NB compares with other animal and human carcinogenic nitroarenes and aromatic amines. Reduced NB first forms the nitroanion free radical, which can react with O2 to form superoxide O2*. Repeated NB dosing produces a persistent redox couple NOB<==>PH in red blood cells (RBCs) that generates met-Hb and expends NAD(P)H. NOB forms activated glutathione (GSH) conjugates. These biochemical effects may lead to critical redox imbalances and macromolecular binding. Known NB effects are hemosiderosis, methemoglobinemia, and anemia--and now dispersed cancer in rodents. On the basis of animal, metabolic and structure-activity studies, NB is determined to be a probable human carcinogen by any route of exposure.
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PMID:Nitrobenzene carcinogenicity in animals and human hazard evaluation. 1048 55

To assess the extent of oxidative stress in erythrocytes of patients with acute Plasmodium falciparum malaria, erythrocyte thiobarbituric acid-reactive substance (ETBAR), and intracellular, membrane and extracellular antioxidants were estimated in 102 cases of P. falciparum malaria and 50 control subjects. The mean concentration of ETBAR was significantly higher (P < 0.001) and many of the antioxidants were significantly lower in patients than controls. Among the erythrocyte antioxidants, catalase, reduced glutathione (GSH) and tocopherol were significantly lower in the patients (P < 0.05, 0.001, 0.001, respectively). Erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were not reduced to a statistically significant level. Similarly, the plasma antioxidants ascorbate and albumin were significantly lower (P < 0.001) but not urate. ETBAR correlated inversely with erythrocyte GSH and tocopherol (P < 0.001), and plasma ascorbate and albumin (P < 0.001) but not with the erythrocyte enzymic antioxidants. However, on multiple regression analysis only tocopherol correlated strongly with ETBAR, followed by GSH and plasma ascorbate. ETBAR also correlated well with haemolytic indices such as haemoglobin, plasma unconjugated bilirubin and haptoglobin concentrations (P < 0.001, for all). On follow-up after 2 weeks, ETBAR and different antioxidants reached near control levels. These observations indicate an enhanced oxidative stress on erythrocytes in acute falciparum malaria that may contribute substantially to haemolysis and anaemia.
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PMID:Evidence for erythrocyte lipid peroxidation in acute falciparum malaria. 1049 92

Glutathione (GSH) is the primary antioxidant in humans. Oxidative cellular injury is postulated to be centrally involved in diverse processes including aging, cancer, cardiovascular disease, and Human Immunodeficiency Virus (HIV) disease progression. Normal plasma GSH concentrations have been well characterized in healthy children and adults, but not during infant development. The objectives of this study were to: a) measure plasma GSH concentrations in non-infected infants born from HIV-infected mothers, to b) assess the developmental variations with age and gender, and c) evaluate for possible associations with growth, anemia, and other maternal and infant variables. One hundred and seventy (170) plasma samples from 44 HIV-uninfected infants (birth to 18 mos.) born to HIV-infected mothers from the Women and Infant Transmission Study (Puerto Rico site) were analyzed. The total plasma GSH geometric mean concentration for all samples analyzed was 1.94 (1.06) mumoles/L. A developmental effect of age was seen with lower concentrations in younger infants (0-2 months) than in older infants 4-18 months. There was no significant effect of gender, anemia, zidovudine exposure, maternal age, maternal CD4 cell percent, or infant growth, although a trend towards increasing GSH concentration was seen with increasing weight for height z-score. These findings have multiple clinical ramifications including prediction of capacity to detoxify oxidants at different ages, and partial explanation for the increased viral loads seen in HIV-infected infants.
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PMID:Plasma glutathione concentrations in non-infected infants born from HIV-infected mothers: developmental profile. 1054 71

The generation of reactive oxygen species (ROS) is a steady-state cellular event in respiring cells. Their production can be grossly amplified in response to a variety of pathophysiological conditions such as inflammation, immunologic disorders, hypoxia, hyperoxia, metabolism of drug or alcohol, exposure to UV or therapeutic radiation, and deficiency in antioxidant vitamins. Uncontrolled production of ROS often leads to damage of cellular macromolecules (DNA, protein, and lipids) and other small antioxidant molecules. A number of major cellular defense mechanisms exist to neutralize and combat the damaging effects of these reactive substances. The enzymic system functions by direct or sequential removal of ROS (superoxide dismutase, catalase, and glutathione peroxidase), thereby terminating their activities. Metal binding proteins, targeted to bind iron and copper ions, ensure that these Fenton metals are cryptic. Nonenzymic defense consists of scavenging molecules that are endogenously produced (GSH, ubiquinols, uric acid) or those derived from the diet (vitamins C and E, lipoic acid, selenium, riboflavin, zinc, and the carotenoids). These antioxidant nutrients occupy distinct cellular compartments and among them, there are active recycling. For example, oxidized vitamin E (tocopheroxy radical) has been shown to be regenerated by ascorbate, GSH, lipoic acid, or ubiquinols. GSH disulfides (GSSG) can be regenerated by GSSG reductase (a riboflavin-dependent protein), and enzymic pathways have been identified for the recycling of ascorbate radical and dehydroascorbate. The electrons that are used to fuel these recycling reactions (NADH and NADPH) are ultimately derived from the oxidation of foods. Sickle cell anemia, thalassemia, and glucose-6-phosphate-dehydrogenase deficiency are all hereditary disorders with higher potential for oxidative damage due to chronic redox imbalance in red cells that often results in clinical manifestation of mild to serve hemolysis in patients with these disorders. The release of hemoglobin during hemolysis and the subsequent therapeutic transfusion in some cases lead to systemic iron overloading that further potentiates the generation of ROS. Antioxidant status in anemia will be examined, and the potential application of antioxidant treatment as an adjunct therapy under these conditions will be discussed.
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PMID:Interaction of antioxidants and their implication in genetic anemia. 1060 86

Visceral leishmaniasis (V.L.) is associated with enhanced lipid peroxidation along with impaired function of antioxidant defense system in erythrocytes. The effect of chronic treatment with ascorbate and alpha-tocopherol was studied on erythrocytes in hamsters infected with Leishmania donovani. Combination treatment with both antioxidants proved to be a potential suppressor of lipid hydroperoxide formation as well as hypotonic osmotic lysis during the leishmanial infection. Positive correlations between the depleted levels of erythrocyte ascorbate, GSH and alpha-tocopherol exhibit proportionate alterations in the nonenzymatic antioxidant levels at different stages of infection. Indirect measurement of transmembrane electron transfer as ferricyanide reduction suggests an active participation of endogenous contents of ascorbate and alpha-tocopherol in the protection against oxidative damage of membrane lipids. Cooperative behavior of both antioxidants in the ferricyanide reducing capacity was further evinced by resealing the ghosts in presence of exogenous ascorbate and alpha-tocopherol. Furthermore, intravesicular ascorbate serves in the defense of extravesicular ferricyanide induced oxidation of endogenous alpha-tocopherol. The results suggest an interacting role of ascorbate and alpha-tocopherol in maintaining the antioxidant reserve of erythrocytes during anemia in V.L.
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PMID:Interaction of ascorbate and alpha-tocopherol enhances antioxidant reserve of erythrocytes during anemia in visceral leishmaniasis. 1119 25

A rare case of hereditary erythrocyte enzymopathy, namely 6-phosphogluconate dehydrogenase (6PGD) deficiency, was found in an Italian family. The activity of the enzyme was reduced to 35% in the propositus and her mother, but was normal in the other three members of the family. The 6PGD deficiency was associated with a variable reticulocyte count and recurrent increased unconjugated bilirubinemia without anemia in the propositus, while no clinical or hematological symptoms were evident in her mother. Increased levels of erythrocyte pyruvate kinase (PK) activity and reduced glutathione (GSH) were observed, indicating a slight decrease in mean red blood cell (RBC) age and an activation of reducing systems. The episodic hemolytic events with jaundice observed in the propositus may be the result of a defective RBC ability to counteract conditions of marked oxidative stress. In this report the importance of 6PGD estimation for a proper analysis of glucose-6-phosphate dehydrogenase (G6PD) deficiency is also highlighted. In fact in the present study, the presence of 6PGD deficiency could be mistaken for a partial G6PD deficiency if the assay of G6PD activity was performed without correcting for 6PGD activity.
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PMID:6-Phosphogluconate dehydrogenase deficiency in an Italian family. 1123 75

Intravenous iron (Fe) and recombinant human erythropoietin (rHuEPO) are routine treatments in the management of anemia in patients with chronic renal failure. We investigated the oxidative stress acutely induced by these therapies and whether pretreatment with oral melatonin (MEL) would have a beneficial effect. Nine patients (four women) were studied within 1 month of entering a chronic hemodialysis program in the interdialytic period. Plasma malondialdehyde (MDA), red blood cell glutathione (GSH), and catalase (CAT) activity were measured in blood samples obtained before (baseline) and 1, 3, and 24 hours after the administration of Fe (100 mg of Fe saccharate intravenously over 1 hour) or rHuEPO (4,000 U intravenously). One hour before these treatments, patients were administered a single oral dose of MEL (0.3 mg/kg) or placebo. Each patient was studied on four occasions, corresponding to studies performed using either placebo or MEL in association with intravenous Fe and rHuEPO administration. Baseline data showed increased oxidative stress in patients with end-stage renal failure. Increments in oxidative stress induced by Fe were more pronounced at the end of the administration: MDA, baseline, 0.74 +/- 0.09 nmol/mL; 1 hour, 1.50 +/- 0.28 nmol/mL (P: < 0.001); GSH, baseline, 2.51 +/- 0.34 nmol/mg of hemoglobin (Hb); 1 hour, 1.66 +/- 0.01 nmol/mg Hb (P: < 0.001); and CAT activity, baseline, 27.0 +/- 5.7 kappa/mg Hb; 1 hour, 23.3 +/- 4.2 kappa/mg Hb (P: < 0.001). rHuEPO-induced increments in oxidative stress were more pronounced (P: < 0.001) at 3 hours (MDA, 1.24 +/- 0.34 nmol/mL; GSH, 1.52 +/- 0.23 nmol/mg Hb; CAT activity, 18.0 +/- 3.1 kappa/mg Hb). MEL administration prevented the changes induced by Fe and rHuEPO and had no adverse side effects. These studies show that intravenous Fe and rHuEPO in doses commonly used to treat anemia in chronic hemodialysis patients acutely generate significant oxidative stress. Oral MEL prevents such oxidative stress and may be of clinical use.
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PMID:Melatonin prevents oxidative stress resulting from iron and erythropoietin administration. 1127 75

This retrospective study has been performed with radiation victims who were accidentally exposed to a 60Co source and its release into the environment. The aim of the study was to assess the effects of elevated radiation exposures on plasma level, on erythrocyte thio barbituric acid reactive substance (TBARS) level and on erythrocyte glutathione (GSH) levels. Patients were treated in different hospitals with different symptoms such as nausea, vomiting, dizziness, along with severe anemia in some patients. Blood samples were collected 3-5 days following the radiation accident. Increases in plasma (6.25 +/- 0.90 nmol ml(-1)) and erythrocyte TBARS levels (330.5 +/- 30.5 micromol gHb(-1)) were found in comparison to a healthy group (3.72 +/- 0.68 nmol ml(-1) and 150.7 +/- 20.5 micromol gHb(-1), respectively) at a significant level (p<0.001). Erythrocyte GSH levels (5.2 +/- 0.30 micromol gHb(-1)) were found to be decreased among the victims (healthy group: 10.2 +/- 0.7 micromol gHb(-1)) at the same significance level (p<0.001). These observations confirm a significant change induced by radiation in the oxidant/antioxidant status among the victims. It is suggested here that antioxidant supplementation therapy might be effective in preventing the harmful effects of 60Co radiation among radiation victims.
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PMID:The effects of exposure of 60Co on the oxidant/antioxidant status among radiation victims. 1246 68

The unknown biochemical basis for neurologic dysfunction in cobalamin deficiency and the frequent divergence between neurologic and hematologic manifestations led us to study homocysteine metabolism in 22 patients with pernicious anemia. Serum levels of total homocysteine (tHcy), methionine, S-adenosylmethionine (AdoMet), cysteine, cysteinylglycine (cys-gly), and glutathione (GSH) were measured. Only levels of tHcy and cysteine were increased and only GSH was decreased in cobalamin deficiency as a whole, compared with 17 control subjects. AdoMet correlated only with methionine levels (P =.015) and cysteine only with cys-gly (P =.007) in healthy subjects, but in cobalamin-deficient patients AdoMet correlated instead with cysteine, cys-gly, and folate levels only (P =.008, P =.03, and P =.03, respectively). Significant differences appeared in clinically subgrouped cobalamin-deficient patients. The 11 patients with neurologic defects had higher mean levels of folate (27.9 versus 15.4 nM), AdoMet (117.2 versus 78.6 nM), cysteine (462 versus 325 microM), and cys-gly (85.0 versus 54.7 microM) than the 11 neurologically unaffected patients. Cobalamin therapy restored all metabolic changes to normal. The results indicate that changes in several metabolic pathways differ in patients with and without neurologic dysfunction. Cysteine levels were the most significant predictors of neurologic dysfunction, but it is unclear if they are direct or indirect indicators of neurotoxicity. The higher AdoMet levels in neurologically affected patients may result from inhibition of glycine N-methyltransferase by those patients' higher folate levels. The origin of the folate differences is unclear and possibly varied. Low AdoMet and GSH levels were independent predictors of anemia.
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PMID:Cobalamin deficiency with and without neurologic abnormalities: differences in homocysteine and methionine metabolism. 1251 17


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