1/95. Familial pseudohyperkalemia maps to the same locus as dehydrated hereditary stomatocytosis (hereditary xerocytosis).Familial pseudohyperkalemia is a "leaky red blood cell" condition in which the cells show a temperature-dependent loss of potassium (K) from red blood cells when stored at room temperature, manifesting as apparent hyperkalemia. The red blood cells show a reduced lifespan in vivo but there is no frank hemolysis. Studies of cation content and transport show a marginal increase in permeability at 37 degrees C and a degree of cellular dehydration, qualitatively similar to the changes seen in dehydrated hereditary stomatocytosis (hereditary xerocytosis). Physiological studies have shown that the passive leak to K has an abnormal temperature dependence, such that the leak is less sensitive to temperature than that in normal cells. We performed genetic mapping on the original family and found that the condition in this kindred maps to the same locus (16q23-ter) that we have previously identified for an Irish family with dehydrated hereditary stomatocytosis, which does not show the same temperature effects.- - - - - - - - - - ranking = 1keywords = cell (Clic here for more details about this article) |
2/95. Haemolytic disease of the newborn due to anti-Ce.A baby was readmitted to the hospital 3 days after delivery when she developed jaundice. At admission, the direct antiglobulin test was also found to be positive. The baby required emergency exchange transfusion. A strongly reacting IgG anti-Ce (Rh7) was found in the serum of the mother. Severe haemolytic disease of the newborn due to anti-Ce is very rare. The mother's serum had been screened and found negative for red cell antibodies at 16 weeks gestation but the test was not repeated later in pregnancy when this antibody might have been detected.- - - - - - - - - - ranking = 0.16666666666667keywords = cell (Clic here for more details about this article) |
3/95. Hereditary non-spherocytic haemolytic anaemia due to red blood cell glutathione synthetase deficiency in four unrelated patients from spain: clinical and molecular studies.In four unrelated patients with chronic haemolysis and markedly reduced red blood cell (RBC) glutathione (49.5%, 12.6%, 11.5% and 15% of the normal concentration respectively), a severe glutathione synthetase (GSH-S, EC 6.3.2.3) deficiency was found. One case exhibited a neonatal haemolytic anaemia associated with oxoprolinuria, but without neurological manifestations. The family study revealed GSH-S activity in both parents to be around half the normal level, a finding consistent with the presumed autosomal recessive mode of inheritance of this enzymopathy. Two cases exhibited a well-compensated haemolytic syndrome without anaemia or splenomegaly at steady state. One of these cases was diagnosed after an episode of acute haemolytic anaemia after fava bean ingestion. The remaining patient suffered from moderate to severe chronic non-spherocytic haemolytic anaemia and splenomegaly, and required occasional blood transfusion for a haemolytic crisis associated with drug ingestion. In this patient, the anaemia was corrected by splenectomy. In addition to GSH-S, a panel of 16 other RBC enzyme activities was also studied in all the patients. hexokinase, aldolase, glucose-6-phosphate dehydrogenase and pyruvate kinase activities all increased; these increases were to be expected, given the rise in the number of circulating reticulocytes. In two patients, the incubation of RBCs with hydrogen peroxide revealed an enhanced production of malonyldialdehyde. dna analysis showed a homozygous state for 656 A-->G mutation in patients 2 and 3. The GSH-S gene of patient 1, studied elsewhere, revealed an 808 T-->C. The GSH-S gene of patient 4 was not available for study. The present study demonstrates that GSH-S deficiency is also present in spain and further supports the molecular and clinical heterogeneity of this enzymopathy- - - - - - - - - - ranking = 0.83333333333333keywords = cell (Clic here for more details about this article) |
4/95. Congenital microangiopathic hemolytic anemia and thrombocytopenia with unusually large von willebrand factor multimers and von willebrand factor-cleaving protease.Infantile or congenital cases of thrombotic microangiopathy have been reported that were familial and characterized by ongoing microangiopathic hemolysis and thrombocytopenia in the absence of regular fresh-frozen plasma transfusions. The authors describe a child with congenital microangiopathic hemolytic anemia and thrombocytopenia (CMHAT) who has received regular fresh-frozen plasma transfusions since infancy and has never had thrombotic complications. von willebrand factor (vWF)-cleaving protease activity was studied in the patient's pretransfusion and posttransfusion plasma samples as well as in her parents' plasma. The effects of the patient's and a control subject's plasma on human microvascular endothelial cells were also investigated. Unusually large vWF multimers were present in the patient's plasma both before transfusion (thrombocytopenic) and after transfusion. Unlike cases of chronic relapsing thrombotic thrombocytopenic purpura, vWF-cleaving protease activity was present and treatment of cultured human endothelial cells with the patient's plasma did not induce apoptosis. These findings suggest that the patient with CMHAT may represent a different group in the broad spectrum of thrombotic microangiopathies.- - - - - - - - - - ranking = 0.33333333333333keywords = cell (Clic here for more details about this article) |
5/95. Hereditary stomatocytosis: membrane and metabolism studies.A defect in the protein kinase-mediated phosphorylation of erythrocyte membrane proteins, previously unrecognized in stomatocytosis, was discovered in a boy with hereditary stomatocytosis and severe hemolytic anemia. The high-sodium, low-potassium erythrocytes of this patient were remarkably permeable to both sodium and potassium. The rate of ouabain-inhibitable active cation transport was more than ten times normal and was sustained by an increase of similar magnitude in glycolysis. The deformability in vitro of fresh stomatocytes was reduced and deteriorated further after a brief period of incubation with glucose. Ferrokinetic studies showed that these rigid cells were sequestered by the spleen. When stomatocytes were deprived of glucose in vitro, ATP depletion and ATPase cation pump failure rapidly ensued. Because of their permeability defect, such depleted cells rapidly became swollen and lysed. Prolonged entrapment in acidic, hypoglycemic regions of the spleen would recapitulate these unfavorable events in vivo. In this regard, splenectomy was followed by an improvement in erythrocyte survival, although evidence of continuing hemolysis was obtained.- - - - - - - - - - ranking = 0.33333333333333keywords = cell (Clic here for more details about this article) |
6/95. Red cell calcium leak in congenital hemolytic anemia with extreme microcytosis.A child with congenital hemolytic anemia, extreme microcytosis and bizarre red cell morphology has been studied. splenectomy at the age of 21 mo greatly improved the hemolytic anemia, although red cell morphology was unchanged. Aniso- and poikilocytosis were marked on a stained smear, and there were many small hyperchromatic cells of irregular shape. The MCV of 25 cu mu was very low and the MCHC was normal. osmotic fragility of fresh blood was increased, and postsplenectomy blood showed a fraction of extremely fragile cells. Concentration and fluxes of Na and K were normal, except K efflux, which was stimulated by external Ca2 . Inward Ca2 movement into the patient's red cells was elevated three- to fourfold above red cells of the same mean age. Red cell Ca2 concentration was raised 2.5 times normal and most of the Ca2 was localized in the stroma. Red cell lipid, sialic acid, and ouabain-binding sites, all per milliliter of cells, were increased by 16%-23%, and, since these substances estimate the amount of membrane, it was likely that Ca2 content per unit of membrane area was at least twice normal. Deformability of the cells, as judged by their filterability was markedly impaired. It was concluded that the red cell membrane was defective, and an increased membrane Ca2 content was associated with reduced deformability, hemolysis, and distorted red cell morphology in this syndrome.- - - - - - - - - - ranking = 2.6666666666667keywords = cell (Clic here for more details about this article) |
7/95. Altered erythrocyte endothelial adherence and membrane phospholipid asymmetry in hereditary hydrocytosis.The risk for thrombosis is increased in patients with hereditary hydrocytosis, an uncommon variant of hereditary stomatocytosis. erythrocytes from 2 patients with hydrocytosis were studied to gain insight into the mechanism of thrombosis in this disorder. erythrocytes demonstrated abnormal osmotic scan ektacytometry and decreased erythrocyte filtration rates. There was also a mild increase in adherence of erythrocytes to endothelial monolayers in a micropipette assay. Adhesion of erythrocytes to the subendothelial matrix proteins thrombospondin and laminin, however, was not significantly increased. Percentages of hydrocytosis erythrocytes and reticulocytes with phosphatidylserine exposed on the outer surfaces were increased in both patients compared with healthy controls, indicating altered membrane phospholipid asymmetry. Increased phosphatidylserine exposure accelerating thrombin-forming processes has been proposed as a mechanism for thrombosis in sickle cell disease and beta-thalassemia and may play a similar role in hereditary hydrocytosis.- - - - - - - - - - ranking = 0.16666666666667keywords = cell (Clic here for more details about this article) |
8/95. Correction of the permeability defect in hereditary stomatocytosis by dimethyl adipimidate.The effect of imidoesters on the extraordinarily increased cation permeability of hereditary stomatocytes was evaluated in erythrocytes from a splenectomized boy with persistent hemolytic anemia. Reaction of stomatocytes with dimethyl adipimidate reduced ouabain-associated potassium loss from 15 to 1.7 and sodium gain from 22 to 2.5 meq per liter of red cells per hours. Red-cell volume, cation concentration, and deformability, previously abnormal, rapidly became normal after stomatocytes were reacted with dimethyl adipimidate. Instead of stomatocytes, normal red cells and target cells were noted. The survival (half-time) of stomatocytes treated with 51Cr-labeled dimethyl adipimidate infused into rats rendered tolerant to human erythorocytes by pretreatment with ethyl palmitate and cobra-venom factor was double that of untreated stomatocytes. Chemical modification of the defect in vitro allowed stomatocytes to regain many properites of normal erythrocytes and favorably influenced the subsequent survival of these cells in vivo.- - - - - - - - - - ranking = 0.83333333333333keywords = cell (Clic here for more details about this article) |
9/95. A family with red cell pyrimidine 5'-nucleotidase deficiency.Congenital hemolytic anemia associated with pyrimidine 5'-nucleotidase deficiency is reported in two siblings. Both have had moderate chronic hemolytic anemia, splenomegaly, and jaundice since early infancy. The peripheral blood smear is characterized by striking red cell basophilic stippling. As this feature has been found in all previously reported cases, it should be the clue to the diagnosis.- - - - - - - - - - ranking = 0.83333333333333keywords = cell (Clic here for more details about this article) |
10/95. Congenital stomatocytosis and chronic haemolytic anaemia.A new case of congenital stomatocytosis associated with haemolytic anaemia, increased autohaemolysis, abnormalities in the erythrocyte metabolism, increased osmotic fragility and shortened erythrocyte survival is described. Intracellular cation concentrations are abnormal: Red cell sodium is high, and potassium is low. The pump rate for monovalent cations is increased.- - - - - - - - - - ranking = 0.33333333333333keywords = cell (Clic here for more details about this article) |
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