Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002895 (sickle cell disease)
 11,747 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sickle cell anemia and other chronic hemolytic anemias are associated with an increased frequency of bacterial infections. There is evidence to suggest that in hemolytic states massive erythrocyte (RBC) ingestion by macrophages interferes with their antibacterial function, thereby predisposing infection. Stimulated by this possibility, we recently demonstrated that erythrophagocytosis by macrophages markedly inhibited intracellular killing of bacteria, and that zymosan-stimulated superoxide generation and chemiluminescence were also suppressed by RBC ingestion. We examined the effects of RBC components on generation of chemiluminescence, superoxide, and bactericidal activity by cell-free oxidative systems. Generation of chemiluminescence by hypoxanthine-xanthine oxidase was depressed in the presence of human RBC lysate or column-fractionated hemoglobin but not crystallized human hemoglobin (methemoglobin) (peak cpms of 15,522 [P = 0.00024], 28,360 [P = 0.0088], and 50,041 [P = 0.37], respectively, compared with 59,898 for positive controls). Similarly, hypoxanthine-xanthine oxidase production of superoxide was inhibited in the presence of column-fractionated human hemoglobin (43.8 versus 17.4 nmol per tube, P = 0.000001). A cell-free bactericidal system, acetaldehyde and xanthine oxidase with or without myeloperoxidase and Cl-, was markedly inhibited by column-purified hemoglobin. For example, after 2 h of incubation, surviving numbers of Staphylococcus aureus were: control (buffer only), 2.5 X 10(6)/ml; bactericidal system, none; bactericidal system plus hemoglobin, 2.2 X 10(6)/ml (P less than or equal to 0.03, bactericidal system versus other systems). Our studies have documented that interactions between RBC (hemoglobin) and reactive products of oxygen metabolism inhibit oxidative bactericidal mechanisms in cell-free systems as well as in macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inhibition of cell-free oxidative bactericidal activity by erythrocytes and hemoglobin. 632 49

Erythrocytes from sickle cell anemia patients and chromatographically purified Hb S0 were incubated with 0.25 to 120 mM acetaldehyde for 15 min to 6 h at different temperatures and pH. Several hemoglobin adducts stable to dialysis were separated by Biorex 70 chromatography and the proportions of the adducts formed were dependent on the period of incubation, acetaldehyde concentration, pH and temperature. Acetaldehyde treatment showed an increase in solubility, minimum gelling concentration and oxygen affinity and a decrease in sickling which showed a dependence on Hb S modification. With 0.25 to 1 mM acetaldehyde, significant inhibition of sickling was observed without any effect on the physical characteristics of the hemoglobin molecule. Acetaldehyde may act as a gelation inhibitor as well as a cell sickling inhibitor.
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PMID:Modification of sickle hemoglobin by acetaldehyde and its effect on oxygenation, gelation and sickling. 711 34