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Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hereditary non-spherocytary haemolytic anaemias have their cause in enzymopathies of the pentose phosphate cycle and the glycolysis of the erythrocytes. The 11 known enzyme defects of the erythrocytary glycolysis in consequence of the reduced preparation of adenosine triphosphatase condition a deficient stability of the membrane of the erythrocytes. Therefore, the increased autohaemolysis in normal osmotic resistance is a reference to these forms of anaemia, which are particularly to be differentiated from hereditary sperocytoses. In Middle Europe the deficiency of pyruvate kinase plays the greatest part among the otherwise rarely diagnosed enzymopenic haemolytic anaemias.
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PMID:[Defects in erythrocyte glycolysis enzymes as the cause of nonspherocytic hemolytic anemia]. 13 17

Specific changes taking place in the erythroid tissue following depletion or replacement of androgens were studied in rats. The reduction of testosterone levels in blood of orchiectomized animals did occur in conjunction with a decline of erythrocyte glucose-6-phosphate (G6P) and lactate levels. No evidence of anemia was observed. The subcutaneous administration of testosterone propionate (16.0 mg/kg) to orchiectomized rats restored, within 12 hours, blood testosterone levels as well as erythrocyte G6P levels and lactate production. The in vitro incorporation of glucose-1-14C into rat erythrocytes incubated with testosterone was comparable to that of control cells. A radioautographic study of rat erythroid marrow pulsed with glucose-1-14C showed a lower labeling when testosterone propionate was administered. The authors conclude that testosterone does directly affect glucose metabolism of erythroid cells, via the pentose shunt pathway. The possible role of the androgen-dependent enhancement of erythroid glycolysis is discussed in relation to the function of testosterone receptocytes present in marrow cells and a 17beta-hydroxysteroid dehydrogenase present in erythrocytes.
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PMID:Effect of androgens on maturation and metabolism of erythroid tissue. 97 90

During follow-up of anemic hemodialysis patients (HDP) treated with recombinant human erythropoietin (rHuEpo), it was noticed that in five HDP, some time after suspension of rHuEpo, hemoglobin (Hb) levels remained at acceptable levels. A metabolic block of the pentose phosphate shunt (PPS) has been described in HDP, which leads to increased oxidative damage of red blood cell (RBC) membranes and increased susceptibility to hemolysis. The increased production of short-chain fatty aldehydes, including malonyldialdehyde (MDA), is an appropriate index of oxidative damage. This study aimed to verify whether the maintenance of acceptable levels of Hb was related to a change in RBC membrane oxidative damage and pentose phosphate shunt activity. In the five HDP in question who required rHuEpo (150 U/kg/week) for severe anemia (Hb = 7.48 +/- 0.95 g/dl), after a stable level of Hb > 10 g/dl was reached for at least 1 month, rHuEpo treatment was stopped. Hb levels remained adequate (Hb = 10.68 +/- 0.77 g/dl) after 14.6 +/- 7.64 months. The oxidative damage was evaluated by measuring RBC MDA (microgram/ml packed RBC) basal levels, and PPS activity by measuring MDA levels after incubation with ascorbate and cyanide (delta % RBC MDA production). Ten anemic HDP not treated with rHuEpo were used as controls (Hb = 8.12 +/- 1.32 g/dl). It was found that the maintenance of adequate levels of serum Hb after suspension of rHuEpo therapy is related to a decrease in RBC membrane oxidative damage (RBC MDA HDP = 2.40 +/- 0.41 vs. RBC MDA controls = 18.23 +/- 6.56; P < 0.005) in consequence of the normalization of pentose phosphate shunt activity.
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PMID:Oxidative damage to RBC membranes and pentose phosphate shunt activity in hemodialysis patients after suspension of erythropoietin treatment. 855 97

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

The erythrocyte is a highly specialized cell whose main functions are oxygen transport and the mediation of carbon dioxide transport. Energy production in the mature erythrocyte depends on glycolysis, with glucose as the principal substrate. Glycolysis and the oxidative pentose phosphate pathway generate NADH and NADPH to reduce methemoglobin, which is being continuously produced, and the antioxidant glutathione, which is present in high concentrations. Red blood cells are equipped with a highly effective antioxidant defense even without the glutathione system. Compared with other cell types, they possess high activities of the most important antioxidant enzymes. Most of the nonenzymatic antioxidant capacity of whole blood is likewise localized in the erythrocytes. Circulating red cells are mobile free radical scavengers and provide antioxidant protection to other tissues and organs. An imbalance between pro-oxidant reactions and antioxidant defense is described in patients with chronic renal failure. Oxidative stress increases as antioxidant defenses are weakened by pro-oxidant hemodialysis factors; it increases further still in renal anemia with a very low red cell count. Thus in terms of free radical metabolism, the only arguments remaining over the complete correction of renal anemia are those in favor, with none against.
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PMID:Erythrocyte free radical and energy metabolism. 1074

Most of the metabolic needs of erythrocytes are covered by glycolysis, the oxidative pentose phosphate pathway and the glutathione cycle. Hereditary enzyme deficiencies of all these pathways have been identified, among which glucose-6-phosphate isomerase (GPI) deficiency is the second most frequent erythroenzymopathy in glycolysis, being associated with non-spherocytic haemolytic anaemia of variable severity. This autosomal recessive genetic disorder may be associated in some cases with neurological impairment. GPI is a dimeric enzyme that catalyses the reversible interconversion of fructose-6-phosphate and glucose-6-phosphate. Virtually all the mutant gene products reported are characterized by marked instability and normal substrate affinities, but altered catalytic activity and electrophoretic migration rates. At the nucleotide level, 29 mutations have been reported. This chapter reviews (a) the clinical pattern of the condition; (b) biochemical and molecular studies; (c) structure-function relationships; (d) the molecular basis of neurological dysfunctions sometimes associated with GPI deficiency; and (e) the correlation between the severity of the anaemia and the molecular defect.
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PMID:Glucose-6-phosphate isomerase deficiency. 1091 80

Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme of the pentose phosphate shunt pathway a major function of which is to prevent cellular oxidative damage. Deficiency in red blood cells is associated with a number of varied clinical manifestations. Chronic non-spherocytic haemolytic anaemia is uncommon but is usually characterized by chronic haemolysis, often with severe anaemia. In the past splenectomy in this condition has been thought to be of questionable benefit. We report a case of G6PD Guadalajara where splenectomy produced transfusion independence and have reviewed the literature. Those cases with exon 10 mutations often have a severe clinical phenotype, which responds to splenectomy. This procedure should be considered in this condition.
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PMID:Glucose-6-phosphate dehydrogenase Guadalajara--a case of chronic non-spherocytic haemolytic anaemia responding to splenectomy and the role of splenectomy in this disorder. 1562 40

The erythrocytes of patients suffering from chronic renal failure (CRF) are exposed to an increased activity of free radicals. These compounds are generated by uremic toxins and hemodialysis itself. They cause the peroxidation of lipids and proteins in red blood cell membrane. It leads to a decrease of erythrocytes' stability and a lower resistance to hemolysis. The advanced oxidation protein products and advanced glycation end products (AOPP and AGE) also contribute to these changes. The described processes deepen the anemia in CRF and make difficulties in its treatment. In addition, the quoted references present a lot of disturbances in activities of the enzymes and metabolic pathways, which provide antioxidant reactions. This group consists of: superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT), glutathione reductase (GSSG-R) end the enzymes of the pentose-phosphate shunt (PPS). The intensity of changes is according to the stage of the disease and the efficiency of treatment. Its most appropriate form is renal transplantation.
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PMID:[Oxidative stress as a reason of treatment difficulties in chronic renal failure]. 1649 15

Deficiencies of enzymes involved in erythrocyte metabolism can have significant effects on erythrocyte function and survival. Animals with pyruvate kinase (PK) or phosphofructokinase (PFK) deficiencies have shortened erythrocyte life spans and regenerative anemia. PK-deficient dogs (but not PK-deficient cats) develop progressive myelofibrosis and osteosclerosis of bone marrow and hemochromatosis and cirrhosis of the liver. PFK-deficient dogs have sporadic episodes of hyperventilation-induced intravascular hemolysis and hemoglobinuria. Cytochrome b5 reductase (Cb5R) deficiency in dogs and cats results in persistent methemoglobinemia and cyanotic mucous membranes. Severe deficiency of glucose-6-phosphate dehydrogenase, the rate-controlling enzyme in the pentose phosphate pathway, resulted in anemia with eccentrocytosis in an American saddlebred colt. Horses with erythrocyte flavin adenine dinucleotide (FAD) deficiency have both eccentrocytosis (attributable to severe deficiency in glutathione reductase activity) and methemoglobinemia (attributable to Cb5R deficiency); the dual enzyme deficiency occurs because FAD is a required cofactor for both enzymes. Erythrocyte enzyme deficiencies do not usually shorten life expectancy, except for PK-deficient dogs and potentially PFK-deficient dogs during a hemolytic crisis. Although enzyme deficiencies are rare causes of anemia and methemoglobinemia, the ability to diagnose deficient animals allows for the possibility of eliminating these undesirable traits in future breeding. DNA-based assays are available for PK and PFK deficiencies; whereas, biochemical tests of enzyme activity are required for other deficiencies. Continued research is needed to document additional enzyme deficiencies that likely occur and to develop additional DNA-based assays to detect heterozygous animals.
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PMID:Pathogenesis, laboratory diagnosis, and clinical implications of erythrocyte enzyme deficiencies in dogs, cats, and horses. 1678 7

Transaldolase (TALDO) deficiency is a rare inborn error of the pentose phosphate pathway. We report the clinical presentation and laboratory findings of a new patient with TALDO deficiency. The two-year-old Arabic boy presented with neonatal onset of anemia and thrombocytopenia, tubulopathy, and rickets and was subsequently found to have cirrhosis and deafness. A comparison with other TALDO deficient patients is given.
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PMID:Transaldolase deficiency in a two-year-old boy with cirrhosis. 1833 7


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