摘要:

AbstractDuring an examination of the effects of shear and of the Ca2+ionophore A23187 on Ca2+entry into erythrocytes of rats and humans, we noted that rat erythrocytes were much more sensitive to Ca2+‐induced hemolysis than the human cells. An examination of the effect of Ca2+on transglutaminase, a cytosolic enzyme in the erythrocyte which crosslinks membrane proteins and renders cells less deformable, demonstrated a correlation between enzyme activity and Ca2+‐induced hemolysis. Both rat and human cells subjected to shear‐induced Ca2+entry exhibited increased enzyme activity and altered membrane protein SDS‐PAGE patterns. Twenty micromolar A23187 with Ca2+at concentrations above 80 μM caused hemolysis of rat erythrocytes. In contrast to human erythrocytes, under these conditions no membranes were recoverable from rat erythrocytes. At lower concentrations of Ca2+(25 and 50 μM), however, rat erythrocytes maintained integrity, and exhibited enhanced transglutaminase activity and cross‐linking of membrane proteins. The rat enzyme can be activated 30% by 10 μM Ca2+, while 50 μM Ca2+was necessary to achieve a similar activation of the enzyme from human red blood cells. In studies of shear‐stimulated Ca2+uptake by erythrocytes the rat red cell enzyme was more readily activated. The SDS‐PAGE pattern of rat red cell membranes after a 30 sec shear showed specific changes in protein banding, including the appearance of bands>330 kDa. Changes in protein banding were also apparent in cytosolic proteins. This work supports the view that shear‐induced Ca2+entry activates transglutaminase that leads to cross‐linking of membrane components, a loss of cell integrity, an

ISSN:0361-8609    

DOI:10.1002/ajh.2830310102

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe de novo pathway of thymidylate synthesis (i.e., methylation of dUMP to dTMP) is directly folate dependent and indirectly vitamin B12(cobalamins) dependent. In deficiency of these vitamins, this pathway is impaired, and exogenous deoxyuridine (dU) fails to suppress adequately in vitro incorporation of [3H]thymidine (3H‐TdR) into DNA via the salvage pathway (i.e., abnormal dU suppression). This abnormality is corrected by the addition of folate compounds (analogues) and/or vitamin B12depending on the nature of the underlying deficiency. We studied the effects of addition of PteGlu, 5‐methyl THF (5‐CH3‐FH4), 5‐formyl‐THF (5‐CHO‐FH4), and hydroxy‐cobalamin (OH‐cbl) on3H‐TdR incorporation into DNA and thymidine kinase activity (salvage pathway), and on [3H]deoxyuridine (3H‐dU) incorporation and dU suppression values (de novo pathway) in cultures of normal and megaloblastic bone marrows. The results showed that3H‐TdR incorporation into DNA and the salvage enzyme, thymidine kinase, activity were greater and3H‐dU incorporation into DNA less in megaloblastic cells as compared with normal cells. The addition of folates significantly reduced3H‐TdR incorporation and thymidine kinase activity and enhanced3H‐dU incorporation in folate and vitamin B12‐deficient cells except that 5‐CH3‐FH4 had no effect on vitamin B12‐deficient cells. None of these additives had any significant effect on normal cells. This study also showed that the addition of the deficient vitamin(s) to the “control tubes” in the dU suppression test is inappropriate, as these vitamins may at least partially correct the defect in cellular DNA synthesis caused by the deficiences of these vitamins and may mask these deficiencies in the results of the in vitro correction of the dU suppression abnormal

ISSN:0361-8609    

DOI:10.1002/ajh.2830310103

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

年代:1989

数据来源: WILEY

摘要:

AbstractCertain metabolic pathways of iron were studied in macrophages (cultured human monocytes) obtained from normal and hemochromatotic subjects. The relative abilities of the hydrophobic ferrous chelator 2,2′ bipyridine and the hydrophilic ferric chelators desferrioxamine (DFO) and diethylenetriaminepenta‐acetic acid (DTPA) to release iron from normal and hemochromatotic macrophages which had previously been loaded with diferric transferrin were tested but there were no differences between the two groups. The relative affinity of the macrophages for diferric transferrin was next studied. Although the hemochromatic macrophages had a somewhat lower affinity for diferric transferrin iron than normal macrophages (Kd4.7 × 10−8M vs. 3.0 × 10−8M) the difference did not reach statistical significance (t = 2.01013;P<0.07). In a further experiment there was no evidence that apotransferrin was directly involved in the release of iron from hemochromatotic macrophages. A clue to the nature of postendocytotic trans‐membrane transport of iron was provided by the finding that it was inhibited by the hydrophobic ferrous chelator 2,2′ bipyridine. However, the degree of inhibition was similar in both normal and hemochromatotic macrophages. In summary, none of the metabolic processes examined in the present study was abnormal in cultured human blood monocytes from hemochromat

ISSN:0361-8609    

DOI:10.1002/ajh.2830310104

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

年代:1989

数据来源: WILEY

摘要:

AbstractSixty‐two previously untreated patients with B‐cell chronic lymphocytic leukaemia were analysed to study the prognostic value of both the immunologic phenotype and the clinicobiologic characteristics. Univariate studies showed that none of the immunological markers analysed, sheep‐rosette, mouse‐rosette, slg, and HLA/DR, CD20, FMC7, CD5, and CD9 antigens, had a significant influence on survival. On the other hand, several clinical and haematological characteristics were identified as being associated with survival: 1) clinical features—presence of lymphadenopathies (P<.05) and hepatomegaly and/or splenomegaly (P<.04); 2) haematologic parameters—presence of anaemia and/or thrombopenia (P<.05), the absolute peripheral blood lymphocyte count (P<.03), and the presence of hypogammaglobulinemia (P<.08); 3) biochemical parameters—serum uric acid (P<.03); and 4) bone marrow histopathological features—biopsy pattern (P<.04) and the percentage of lymphocytes in bone marrow aspirate (P<.03). Both the Rai staging and the International Workshop on CLL staging systems were effective in identifying groups of patients with significantly different prognoses (P<.05). Multivariate regression analysis demonstrated that the combination of three clinicopathologic characteristics (bone marrow histopathologic pattern, absolute peripheral blood lymphocyte count, and the presence or not of hypogammaglobulinaemia) had the strongest predictive relationship with survival time.In summary, our findings show that the clinicobiological and anatomopathologic parameters have much more prognostic relevance than the immunological markers analysed in th

ISSN:0361-8609    

DOI:10.1002/ajh.2830310105

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe intravenous infusion of 1‐deamino‐8‐D‐arginine vasopressin (DDAVP) is used as a nontransfusional form of treatment in patients with congenital and acquired bleeding disorders, including patients with uremia associated with prolonged bleeding times. Since uremic patients experience minor bleeding episodes that might be self‐managed at home (particularly epistaxis, gingival bleeding, and menorrhagia), we carried out a double‐blind, placebo‐controlled crossover study in nine uremics to evaluate whether the prolonged bleeding times could be shortened by subcutaneous injections of DDAVP. One hour after administration, the bleeding time was significantly shortened (P<.01) and became normal in seven of nine patients. After 4 hr, the bleeding time was still shorter than baseline (P<.01), but in only three patients was it still normal. There was no significant bleeding time change after placebo. When the same patients were treated with the same dose of DDAVP infused intravenously, the bleeding times were not significantly different from those measured after subcutaneous administration. Hence, subcutaneous DDAVP is an alternative method for short‐term shortening of the bleeding time in uremia, at least as effective as intravenous DDAVP but with the possibility of self‐administration by the

ISSN:0361-8609    

DOI:10.1002/ajh.2830310106

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

年代:1989

数据来源: WILEY

摘要:

AbstractThe extrinsic fibrinolytic system and its response to cigarette smoking was studied in five healthy male smokers 35–45 years old. Tissue plasminogen activator (t‐PA) release in response to venous occlusion was intact both at 8:00 A.M. and 3:00 P.M. Acutely smoking two cigarettes neither stimulated fibrinolysis nor changed levels of t‐PA or plasminogen activator inhibitors. Functional plasminogen activator inhibitor (PA‐I) levels and euglobulin lysis times were higher in the smoking group than in a control group matched for age, sex, and body mass. Antigenic levels of PA‐I 1, the PA‐I derived from vascular endothelial cells and platelets, were similar in both groups. While smoking did not acutely alter fibrinolysis in chronic smokers, these individuals had a high frequency of abnormal fibrinolysis characterized by high levels of PA‐I activity. This abnormality is due to either high specific activity of PA‐I 1 or to the presence of other antigenically distinct plasminogen activator inhibitors. Abnormal firbinolysis may be one mechanism contributing to the thrombotic diathesis of ci

ISSN:0361-8609    

DOI:10.1002/ajh.2830310107

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

年代:1989

数据来源: WILEY

摘要:

AbstractCommercial concentrates of factor VIII (FVIII) were analyzed in order to 1) determine the effects of viral inactivation on von Willebrand factor (vWF); 2) evaluate the vWF content of the new, immunopurified concentrates; and 3) assess their potential for correcting the long bleeding time of von Willebrand disease (vWD). Included in our study were products that had been treated to inactivate viruses; older, untreated products; and the new, immunopurified concentrates. We measured von Willebrand factor antigen (vWF:Ag), ristocetin cofactor activity (RCoF), and vWF multimeric and subunit composition. A newly developed radioimmunoassay (RIA) was used to quantitate vWF:Ag. The vWF:Ag content varied from 0.083 μg/IU FVIII:C for Hemofil M to 32.2 μg/IU FVIII:C for Humate‐P, whereas pooled normal human plasma (NHP) contained 6.3 μg/IU FVIII:C. The RCoF varied from 0.0007 to 2.09 U/IU FVIII:C, with the immunopurified concentrates having the lowest values and Humate‐P the highest. The ratio of RCoF to vWF:Ag ranged from 11 to 96 U/mg, as compared to a ratio of 160 for NHP. All of the concentrates lacked the largest vWF multimers, and all had abnormal triplet patterns. Modest differences between some untreated concentrates and their treated counterparts were noted. As expected, the immunopurified concentrates had much lower levels of all vWF activities than the conventionally prepared products. Our data suggest that none of the concentrates have as great a capacity as NHP to correct the prolonged bleeding time of von Willebrand d

ISSN:0361-8609    

DOI:10.1002/ajh.2830310108

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

年代:1989

数据来源: WILEY

摘要:

AbstractTo determine the incidence of thrombocytosis at presentation in acute lymphoblastic leukemia (ALL), medical records of all children diagnosed at the Children's Hospital of Pittsburgh from 1980 to 1987 were reviewed. Out of 217 such patients, 7 (3.2%) had platelet counts greater than 400,000/mm3. All of the seven were boys compared with a male:female ration of 1.4:1 in the entire ALL population. Other than sex, no characteristics were clearly associated with thrombocytosis, including white blood cell count, hemoglobin, lymphoblast morphology, and immunologic or chromosomal markers. Apart from ALL, no inflammatory or infectious process which might have caused a thrombocytosis, was detected in any of these patients. The period of induction therapy was notable for the preservation of platelet counts greater than 20,000/mm3in all patients. However, of the seven children with thrombocytosis, two had major induction complications: one, a cavernous sinus thrombosis; and the other, gastrointestinal bleeding with duodenal perforation.We conclude that thrombocytosis at diagnosis can be seen in children, particularly boys, with ALL. Based on small numbers, this group of patients may be at risk for major events during induction therapy. Large numbers, longer follow‐up, and platelet function studies on similar patients will be of interes

ISSN:0361-8609    

DOI:10.1002/ajh.2830310109

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

年代:1989

数据来源: WILEY

摘要:

AbstractPseudothrombocytopenia is an in vitro phenomenon usually associated with anticoagulant (EDTA)‐dependent IgG platelet agglutinins. A low Coulter platelet count was investigated in a 63‐year‐old woman with multiple sclerosis and a monoclonal IgM kappa gammopathy. An unusual type of EDTA‐ and temperature‐independent IgM platelet agglutinin was identified by in vitro agglutination of donor platelets and was removed by immunoa

ISSN:0361-8609    

DOI:10.1002/ajh.2830310110

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

年代:1989

数据来源: WILEY

摘要:

AbstractHyperfibrinolytic states are reported to be a cause of bleeding in patients with amyloidosis. We reviewed the literature on excessive fibrinolysis in association with amyloidosis and report our findings from a patient with idiopathic amyloidosis who developed a bleeding diathesis. Coagulation laboratory studies indicated elevated plasminogen activator levels associated with a reduction of plasminogen and α2‐plasmin inhibitor (α2‐PI) levels. The level of tissue‐type plasminogen activator (t‐PA) inhibitor and t‐PA antigen were normal. However, the patient did have a five‐ to sevenfold increase in amidolytic activity for the urokinase substrate pyro‐Glu‐Gly‐Arg‐pNA (S‐2444). This case therefore represents a novel example of a hyperfibrinolytic state associated with amyloidosis caused by elevated urokinase‐type plasminogen activator (u‐PA). Epsilon‐amino caproic acid (EACA) therapy resulted in an increase in α2‐PI and plasminogen levels and effectively reduced the blood loss. Hyperfibrinolytic states in amyloidosis have now been reported to be due to elevated t‐PA an

ISSN:0361-8609    

DOI:10.1002/ajh.2830310111

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

年代:1989

数据来源: WILEY