1/5. 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 = 1keywords = volume (Clic here for more details about this article) |
2/5. Haemolytic anaemia in analpha-lipoproteinaemia (tangier disease): morphological, biochemical, and biophysical properties of the red blood cell.A patient with familial analpha-lipoproteinaemia (tangier disease) was found to have stomatocytosis and haemolytic anaemia. The analysis of the red cell membrane constituents revealed a low cholesterol content (90 nmol/ml red cells, control 130 nmol/ml red cells), a decreased cholesterol/phospholipid ratio (0.54, control 0.78), high phosphatidylcholine (41.5%, control 30.6%) and low sphingomyelin (18.8%, control 27.6%). The electrophoretic membrane protein pattern was normal. Osmotic gradient ektacytometry and osmotic resistance showed a decreased surface/volume ratio, which caused an increased filtration resistance in 3 microns pores. The elasticity of the membrane was unchanged. Functional membrane properties were altered: the anion exchange rate was increased, whereas alkali cation fluxes were normal. The capacity to release vesicles was reduced. This case represented a new type of stomatocytosis. It contributes to the understanding of the role of cholesterol and phospholipids in the red cell membrane and biomembranes in general.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
3/5. Reduction of membrane band 7 and activation of volume stimulated (K , Cl-)-cotransport in a case of congenital stomatocytosis.We report on a case of congenital stomatocytosis in a French boy presenting with a haemolytic anaemia requiring splenectomy at the age of 6. The red cells included 15-20% stomatocytes and displayed a marked increase of volume. Their osmotic resistance and density were reduced; however, their deformability was unaltered in isotonicity. Erythrocyte Na was high (27 mEq/l) and K low (65 mEq/l). The newly described (K , Cl-)-cotransporter normally triggered by hypo-osmotic stress, was activated to maximal capacity. Membrane band 7 was reduced by 72%. From anamnestic data, the condition appears to have been transmitted by the father. The mother proved to be strictly normal on clinical, morphological, osmotic and biochemical bases. We suggest that the partly missing band 7 may play an important role in the genesis of stomatocytosis.- - - - - - - - - - ranking = 5keywords = volume (Clic here for more details about this article) |
4/5. Variant type of congenital stomatocytosis.A 52-year-old female with congenital stomatocytosis showed hemolytic anemia, an increased mean corpuscular volume (MCV), and mean corpuscular hemoglobin concentration (MCHC), reticulocytosis and an increased osmotic fragility. Lipid and protein content of membranes, the activities of membrane-associated enzymes in erythrocytes and the elution pattern of hemoglobin were normal. Erythrocyte Na influx was moderately increased and Na efflux, particularly ouabain-insensitive Na "leak-out" was also increased. K concentration of erythrocytes was abnormally low with a slightly increased Na content. These phenotypes are very rare, and should be classified as a variant type.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |
5/5. Compensatory mechanisms for the severe anaemia caused by haemoglobin Hammersmith.A severely anaemic, but asymptomatic patient, who is a heterozygous carrier of haemoglobin Hammersmith (beta42 (CD1) phenylalanine - serine), has been studied to elucidate the mechanisms resulting in physiological compensation for the anaemia. Four factors have been investigated: the oxygen affinity of her blood, the cardiac output at rest and during exercise, the blood gas indices, and pulmonary function. It was found that due to the presence of heinz bodies within the erythrocytes, the level of functional, haemoglobin was considerably less (50 g/l) than that measured by standard methods (87 g/l). In addition a moderate degree of arterial hypoxaemia (arterial oxygen tension = 10.7 kPa (80.4 mmHg) was present which could not be explained on the basis of abnormal pulmonary function. Both of these factors would result in tissue hypoxia, but the finding of consistently normal oxygen tensions ('mixed' venous oxygen tension = 5.4 kPa (40.3 mmHg) in blood obtained from the right atrium, suggested that hypoxia was not present. This was explained by a decreased whole blood oxygen affinity (P50 = 4.6 kPa (34.5 mmHg) at pH 7.4) and an increase in the cardiac index (5.3 L.min.-1m-2). The latter was the result of an increased stroke volume (125 - 135 ml), the heart rate being normal (63/min.). During moderate exercise, further increases at cardiac output were brought about by a change in heart rate alone. It has been calculated that the decrease in whole blood oxygen per se could not account for adequate tissue oxygenation. This is confirmed by the finding of an increased cardiac output in this patient. It is suggested that in any severe haemolytic anaemia, even if the whole blood oxygen affinity is low, cardiac output is probably increased to achieve complete physiological compensation.- - - - - - - - - - ranking = 1keywords = volume (Clic here for more details about this article) |