摘要:

AbstractThree types of unusual, elongated erythrocytes have been studied in our effort to understand factors that regulate the shape and deformability of red blood cells. Measurements of deformability, morphologic response to membrane‐shape‐altering drugs, spectrin phosphorylation, spectrin extractability, and casein kinase activity were measured in llama cells, irreversibly sickled cells, and nonhemolytic human elliptocytes. The results of these studies support the concept that the physical properties of spectrin are important in maintaining the shape and deformability of the erythrocyte. Furthermore, changes in spectrin extractability and phosphorylation appear to be associated with changes in the viscoelastic properties of the membrane. However, it seems that spectrin's regulatory role is permissive rather than direct and act

ISSN:0361-8609    

DOI:10.1002/ajh.2830080102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractBone marrow cells, peripheral blood lymphocytes, and sera from patients with sickle‐cell anemia in hypoproliferative crisis were studied in the plasma clot culture system in the presence or absence of erythropoietin (Epo). Bone marrow cells from five patients demonstrated a marked ability to form erythroid colonies in the presence of Epo. These studies also suggested that bone marrow cells from some patients may have an increased sensitivity to Epo. The most outstanding observation in the present study was the marked erythroid colony inhibition by serum taken from one patient during crisis. Serum taken from the same patient two months after hypoproliferative crisis had no suppressive effect on erythroid colony formation. Lymphocytes taken from three patients in crisis had a stimulatory effect on erythroid colony formation when included in culture. The conclusion is that the defect of erythropoiesis in sickle‐cell anemia during hypoproliferative crisis is not due to the absence of erythroid precursor cells or to the presence of suppressor lymphocytes, but may in some cases be associated with a circulating inhibitor of erythroid maturat

ISSN:0361-8609    

DOI:10.1002/ajh.2830080103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThree patients were studied who had acquired hemolytic anemia during pregnancy. One patient had a relapsing hemolytic anemia of pregnancy with a negative direct antiglobulin test. Previously reported cases have been presumed to be antibody‐mediated because of rapid destruction of transfused blood, transient hemolysis in the newborn, and a favorable response to corticosteroid therapy. Our findings with the complement‐fixation antibody consumption (CFAC) test offer support for an immune pathogenesis, since we documented abnormal concentrations of IgG on the patient's red cells during pregnancy and also on a sample of cord blood. The hemolytic anemia responded partially to prednisone during pregnancy and resolved postpartum. A repeat CFAC test postpartum revealed a marked reduction in the number of IgG molecules per red cell on the mother's cells, and IgG was no longer detectable on the infant's red cells.The other patients had serologic abnormalities characteristic of an autoimmune hemolytic anemia with an IgG warm autoantibody. The patients were followed closely during pregnancy because of previous reports of life‐threatening morbidity in mothers, as well as stillbirths, neonatal death, and seriously affected infants. An amniocentesis was performed in one patient because of persistent hemolysis in spite of prednisone therapy. The mothers and their infants did well, but serologic abnormalities and mild hemolytic anemia persisted in both mothers. Therefore, an elective splenectomy was performed with significant improvement in both inst

ISSN:0361-8609    

DOI:10.1002/ajh.2830080104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractHuman erythrocytes were separated by buoyant density ultracentrifugation into fractions of progressively increasing mean cell age to measure the changes in glycolytic activity that occur during their 120‐day life‐span. The maximal activities of all glycolytic enzymes were shown to decline exponentially with cell age. Only three glycolytic enzymes exhibited a marked rate of decline with a t1/2shorter than the cell life‐span: hexokinase, aldolase, and pyruvate kinase.Glucose utilization, when measured in steady‐state conditions (1 mM inorganic phosphate), showed a fourfold decrease through the erythrocyte life‐span; lactate production also declined, but at a slower rate. When incubating conditions were altered by the introduction of a metabolic stimulus (either high phosphate for glycolysis, or methylene blue for the pentose pathway) the youngest cell fractions responded with decidedly increased rates of glucose consumption and lactate production. However, this ability gradually declined with cell aging, and ultimately, the oldest cells had metabolic rates as low as if there were no stimulus present. The oldest erythrocytes appear to have lost the flexibility needed to respond to metabolic stress and are more vulnerable to events in the circulation that may require the ability to increase the basal rate. This defect is probably responsible for the disappearance of aged erythrocytes from the ci

ISSN:0361-8609    

DOI:10.1002/ajh.2830080105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThese studies were designed to explore further the interrelationships between various stem cell and other hematopoietic compartments of the mouse. Busulfan (BU) has been shown by others to have a profound effect on the transplantable pluripotent stem cells capable of forming colonies on spleens (CFU) of lethally irradiated recipients – more so than on cells of differentiated compartments. Another presumed assay of pluripotent stem cells consists of counting colonies on spleens of nontransplanted sublethally irradiated mice as a quantitation of endogenous colony‐forming units (E‐CFU). We examined and compared BU‐induced damage and recovery as measured by E‐CFU, CFU, CFU‐C, total cellularity of marrow, peroxidase‐positive cells per marrow, spleen weight, radioactive iron uptake into spleen and marrow, and hematocrit. E‐CFU were severely damaged by BU, but recovery was significantly more rapid than that measured for CFU. These results were compatible with other data suggesting that cycling stem cells are more likely to survive radiation and less likely to survive removal and transplantation. Thus, the actual number of pluripotent stem cells lies between the CFU and E‐CFU values. Damage to more mature granulocytic and erythrocytic compartments lagged behind damage to E‐CFU and CFU. Abortive rises in these more mature compartments were observed, which suggested limited but distinct self‐replication activity of “stem cells” more differentiated than the CFU, E‐CFU systems. Time of final recovery of the damaged hematopoietic system was compatible with a concept of recovery of pluripotent stem cell system(s) preceding recovery

ISSN:0361-8609    

DOI:10.1002/ajh.2830080106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThe members of the American Society of Hematology were surveyed to determine their experience in the treatment of patients with severe aplastic anemia (AA) with cyclophosphamide (CYT). Among the 401 members responding, 50 had treated AA patients, and three remissions were reported. These remissions can be explained either by response to CYT in a subgroup of patients with AA due to an immune mechanism or to spontaneous remission. Clinical trials of the efficacy of cytotoxic drugs in the treatment of AA patients will not likely permit a distinction between drug effect and spontaneous remission until the subgroup of patients with immune‐mediated AA is identified through the development of more sensitive and specific in vitro test

ISSN:0361-8609    

DOI:10.1002/ajh.2830080107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractLiquid culture of the mononuclear fraction of the blood of marmosets without any added stimulator resulted in the appearance of megakaryocytes. These cells could not be identified by light microscopy or by indirect immunofluorescence using antiplatelet antiserum. Ultrastructural idetification was made using platelet peroxidase. Some megakaryocytes demonstrated sparse but detectable demarcation membranes, early granule formation, and platelet formation.The results indicate that marmoset megakaryocytic progenitor cells circulate and can begin to differentiate in vitro, although unstimulated liquid culture conditions do not promote the development of the usual light‐microscopic features of differentiatio

ISSN:0361-8609    

DOI:10.1002/ajh.2830080108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractProtein synthesis, respiration, and oxidative phosphorylation were studied in mitochondria isolated from normal, myeloid, and erythroid hyperplastic bone marrow of rabbits. Mitochondria from normal and myeloid hyperplastic marrow showed a similar degree of14C‐leucine incorporation while a threefold higher activity was demonstrated in mitochondria from erythroid marrow. The incorporation was mitochondrial‐concentration‐dependent and in all cases was inhibited by low concentrations of chloramphenicol (CAP). The respiratory activity of mitochondria isolated from either myeloid or erythroid marrow was twice as high as the normal, but in all cases respiration and phosphorylation were unaffected by concentrations of CAP which totally inhibited protein synt

ISSN:0361-8609    

DOI:10.1002/ajh.2830080109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractIn two patients with recurrent immune thrombocytopenia, accessory splenic tissue was demonstrated by radionuclide imaging following administration of indium 111‐labeled autologous platelets. In one of these patients, no accessory splenic tissue was seen on images obtained with technetium 99m sulfur colloid. This new technique provides a simple means for demonstrating accessory spleens and simultaneously evaluating the life‐span of autologous platel

ISSN:0361-8609    

DOI:10.1002/ajh.2830080110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractA nine‐year‐old black girl with essential thrombocythemia developed hemoptysis. Only two other cases in the English literature have been described. Ultrastructure and functional characteristics of this patient's platelets were studied. Twenty‐six percent of the patient's platelets were very large (megathrombocytes). Spontaneous aggregates from the patient's platelets were not compact, and the pseudopods did not interdigitate. Both qualitative and quantitative defects in platelet organelles were detected. The microtubular system was faulty in organization. Furthermore, the number of granules (especially alpha granules) was reduced. Platelet aggregation studies demonstrated subnormal aggregation in response to ADP, epinephrine, and collagen, but aggregation with ristocetin was normal. It is postulated that a platelet membrane abnormality may be the cause of their defective platelet aggreg

ISSN:0361-8609    

DOI:10.1002/ajh.2830080111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY