Extraction of erythrocyte membrane proteins by sulfhydryl inhibitors.
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Human red cell membrane proteins were extracted by incubation of the ghost with hypotonic phosphate buffer (pH 7.4), N-ethylmaleimide and p-hydroxy-mercuribenzoate. In paroxysmal nocturnal hemoglobinuria (PNH), hereditary spherocytosis (HS) and hereditary elliptocytosis, the amount of proteins extracted by these procedures was significantly less than the amount extractable from the ghost of normal and aplastic anemia red cells. Polypeptide patterns of red cell membranes in these hematological disorders were essentially similar to those of normal ghosts. Analysis of the supernatant by SDS polyacrylamide gel electrophoresis revealed that this reduction was mainly due to the reduced amount of peripheral proteins extracted. The extraction of peripheral proteins by sulfhydryl reagents was accompanied by shape changes resulting in the formation of membrane vesicles, suggesting an important role of peripheral proteins in the maintenance of ghost shape. It is also suggested that qualitative abnormalities of peripheral proteins such as altered reactivity to sulfhydryl reagents and/or strong binding to the membrane are present in PNH, HS and hereditary elliptocytosis red cells. (+info)
Acute onset hemoglobinemia and/or hemoglobinuria and sequelae following Rh(o)(D) immune globulin intravenous administration in immune thrombocytopenic purpura patients.
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Rh(o)(D) immune globulin intravenous (anti-D IGIV) was licensed by the United States Food and Drug Administration (FDA) in March 1995 to treat patients with immune thrombocytopenic purpura (ITP). Anti-D IGIV induces extravascular hemolysis, an expected adverse reaction that is consistent with the presumed mechanism of action. Between licensure and April 1999, the FDA received 15 reports of hemoglobinemia and/or hemoglobinuria following anti-D IGIV administration that met the case definition for this review. The mechanism responsible for hemoglobinemia and/or hemoglobinuria is unexplained. Review of these reports was prompted by the seriousness and the unexpectedness of treatment-associated sequelae experienced by 11 patients. Of these patients, 7 developed sufficient onset or exacerbation of anemia that orders were written for packed red blood cell transfusions, although only 6 patients were transfused. Eight patients experienced the onset or exacerbation of renal insufficiency, and 2 patients underwent dialysis. One patient died due to complications of exacerbated anemia. Six patients experienced 2 to 3 sequelae. Absent validated incidence data, a 1.5% estimated incidence rate from published clinical trial data and a 0.1% estimated reporting rate from FDA and drug utilization data were calculated for reported cases of hemoglobinemia and/or hemoglobinuria. This review presents the first case series of anti-D-IGIV-associated hemoglobinemia and/or hemoglobinuria and provides pretreatment and posttreatment clinical and laboratory findings of the case series patients. The primary purpose of this review is to increase awareness of this potentially serious occurrence among physicians and health care professionals who manage ITP patients treated with anti-D IGIV, thereby enabling prompt recognition and treatment of sequelae. (Blood. 2000;95:2523-2529) (+info)
A model for the sickle hemoglobin fiber using both mutation sites.
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The standard molecular model of the fiber of the sickle hemoglobin (HbS: beta6 Glu-->Val) has been revised to allow both beta6 mutation sites to participate in intermolecular contacts, rather than only one beta6 site as previously thought, for four molecules per 14-molecule fiber cross section. This structure accurately predicts the copolymerization of hybridized mixtures of HbS with HbA or HbC (beta6 Glu-->Lys), which could not be reconciled with prior models in which only half the beta6 sites were required for assembly. This model suggests new contacts within the fiber and raises the question of whether these cross-linked double strands could possess added stability important in such processes as nucleation. (+info)
Haemolysis complicating viral hepatitis in patients with glucose-6-phosphate dehydrogenase deficiency.
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Out of 20 patients with viral hepatitis whose glucose-6-phosphate dehydrogenase (G-6-PD) levels were normal, 14 had clinical evidence of a mild to moderate degree of haemolysis but in all the patients studied the half life of chromium-51-labelled red cells was shortened. Out of 18 viral hepatitis patients deficient in G-6-PD 17 had clinical evidence of haemolysis, and in eight this was more severe than in the group with normal G-6-PD values. Massive intravascular haemolysis occurred in four, three of whom died. The massive haemolysis was attributed to the presence of additional drug-induced oxidative stress to the G-6-PD-deficient red cells. (+info)
Immune system dysfunction and autoimmune disease in mice lacking Emk (Par-1) protein kinase.
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Emk is a serine/threonine protein kinase implicated in regulating polarity, cell cycle progression, and microtubule dynamics. To delineate the role of Emk in development and adult tissues, mice lacking Emk were generated by targeted gene disruption. Emk(-/-) mice displayed growth retardation and immune cell dysfunction. Although B- and T-cell development were normal, CD4(+)T cells lacking Emk exhibited a marked upregulation of the memory marker CD44/pgp-1 and produced more gamma interferon and interleukin-4 on stimulation through the T-cell receptor in vitro. In addition, B-cell responses to T-cell-dependent and -independent antigen challenge were altered in vivo. As Emk(-/-) animals aged, they developed splenomegaly, lymphadenopathy, membranoproliferative glomerulonephritis, and lymphocytic infiltrates in the lungs, parotid glands and kidneys. Taken together, these results demonstrate that the Emk protein kinase is essential for maintaining immune system homeostasis and that loss of Emk may contribute to autoimmune disease in mammals. (+info)
Targeted deletion of the CD59 gene causes spontaneous intravascular hemolysis and hemoglobinuria.
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The glycolipid-anchored glycoprotein CD59 inhibits assembly of the lytic membrane attack complex of complement by incorporation into the forming complex. Absence of CD59 and other glycolipid-anchored molecules on circulating cells in the human hemolytic disorder paroxysmal nocturnal hemoglobinuria is associated with intravascular hemolysis and thrombosis. To examine the role of CD59 in protecting host tissues in health and disease, CD59-deficient (CD59(-/-)) mice were produced by gene targeting in embryonic stem cells. Absence of CD59 was confirmed by staining cells and tissues with specific antibody. Despite the complete absence of CD59, mice were healthy and fertile. Erythrocytes in vitro displayed increased susceptibility to complement and were positive in an acidified serum lysis test. Despite this, CD59(-/-) mice were not anemic but had elevated reticulocyte counts, indicating accelerated erythrocyte turnover. Fresh plasma and urine from CD59(-/-) mice contained increased amounts of hemoglobin when compared with littermate controls, providing further evidence for spontaneous intravascular hemolysis. Intravascular hemolysis was increased following administration of cobra venom factor to trigger complement activation. CD59(-/-) mice will provide a tool for characterizing the importance of CD59 in protection of self tissues from membrane attack complex damage in health and during diseases in which complement is activated. (+info)
Conservative treatment of hemolytic complication following coil embolization in two adult cases of patent ductus arteriosus.
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Two adult cases of relatively large patent ductus arteriosus (PDA) were treated by coil embolization, but were complicated by hemolysis that was successfully managed by medical treatment. Case 1 was a 67-year-old woman and Case 2 was a 71-year-old woman with a PDA of minimal diameter of 5.3 mm and 5.5 mm, respectively. The approach was via the pulmonary artery and 2 coils were delivered simultaneously into the ductus, known as the 'kissing coil technique'. Although immediately after the procedure only a small residual shunt was revealed by aortogram, hemolysis occurred for several hours after the procedure in both cases. A hemolytic complication usually needs additional coil embolization or surgical treatment, but in these 2 cases it was successfully treated by haptoglobin infusion to prevent nephropathy and by antiplasmin infusion to promote thrombus formation. Hemolytic complications of coil embolization of PDA can managed by medication when the residual shunt is minimal and the degree of hemolysis is mild. (+info)
Exertional hemoglobinuria.
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A 16 years old boy had a typical exertional hemoglobinuria after walking with his new leather shoes on. The attacks of hemoglobinuria were associated with the appearance of an unstable hemoglobin in red cells. A slightly decreased fragility curve by 24 hr incubated red cells, the increase of autohemolysis and the appearance of heat labile hemoglobin were observed after exertion. These findings support that exertional hemoglobinuria may be regarded as a transitory erythropathia. (+info)