bluuebunny/crossref_metadata_2025 huggingface dataset:
Contribution of the band 3-ankyrin interaction to erythrocyte membrane mechanical stability
Authors: Low PS , Willardson BM , Mohandas N , Rossi M , Shohet S
Published: October 2019

In an effort to evaluate the role of the band 3-ankyrin linkage in maintenance of red blood cell membrane integrity, solution conditions were sought that would selectively dissociate the band 3-ankyrin linkage, leaving other membrane skeletal interactions intact. For this purpose erythrocytes were equilibrated overnight in nutrient-containing buffers at a range of elevated pHs and then examined for changes in mechanical stability and membrane skeletal composition. Band 3 was found to be released from interaction with the membrane skeleton over a pH range (8.4 to 9.5) that was observed to dissociate the band 3- ankyrin interaction in vitro. In contrast, all other membrane skeletal associations appeared to remain intact up to pH 9.3, after which they were also seen to dissociate. Whereas hemolysis of mechanically unstressed cells did not begin until approximately pH 9.3, where the membrane skeletons began to disintegrate, enhanced fragmentation of shear stressed membranes was seen to begin near pH 8, where band 3 dissociation was first observed. Furthermore, the shear-induced fragmentation rate was found to reach a maximum at pH 9.4, ie, where band 3 dissociation was essentially complete. Based on these correlations, we hypothesize that the band 3-ankyrin linkage of the membrane skeleton to the lipid bilayer is essential for red blood cell stability in the face of mechanical distortion but not for cellular integrity in the absence of mechanical stress.
Pentoxifylline (Trental) decreases the replication of the human immunodeficiency virus type 1 in human peripheral blood mononuclear cells and in cultured T cells [see comments]
Authors: Fazely F , Dezube BJ , Allen-Ryan J , Pardee AB , Ruprecht RM
Published: October 2019

Pentoxifylline (Trental), used routinely for the treatment of intermittent claudication, has been shown previously to decrease the levels of tumor necrosis factors-alpha (TNF-alpha) RNA in cancer patients and to lead to a general improvement of well being. Increased TNF-alpha levels have been observed not only in cancer patients but also in cachectic patients with the acquired immunodeficiency syndrome (AIDS), and TNF-alpha is known to increase the expression of the human immunodeficiency virus type 1 (HIV-1) via activating its long terminal repeat (LTR). Moreover, TNF-alpha decreases the therapeutic efficacy of zidovudine (AZT). Here we show a significant decrease in HIV-1 replication by pentoxifylline in infected human peripheral blood mononuclear cells. The reduction was proportional to the downregulation of expression of a reporter gene, the bacterial gene for chloramphenicol acetyl transferase, linked to the HIV-1 LTR in human monocytoid cells. We conclude that patients with AIDS may benefit from pentoxifylline treatment because of its blockage of TNF-alpha-mediated HIV-1 upregulation, from increased efficacy of AZT, and also from improvement in TNF-alpha-induced cachexia.
Molecular evaluation of response to all-trans-retinoic acid therapy in patients with acute promyelocytic leukemia
Authors: Lo Coco F , Avvisati G , Diverio D , Petti MC , Alcalay M , Pandolfi PP , Zangrilli D , Biondi A , Rambaldi A , Moleti ML
Published: October 2019

The advent of retinoic acid (RA) in the treatment of acute promyelocytic leukemia (APL) has led to a high frequency of short- lasting complete remissions (CR). We studied the response to RA by molecularly analyzing the RA receptor alpha (RAR alpha) locus, which has recently been shown to be rearranged in all APLs. Southern blot analysis demonstrated that the RAR alpha rearrangements persisted in the APL samples containing maturing myeloid cells 2 to 3 weeks after the start of RA treatment, but disappeared after 5 to 8 weeks, when the patients achieved CR. Our investigations provide clear evidence that CR occurs at molecular level and that there is reconstitution of an apparently normal, nonclonal hematopoiesis. Further, it shows that RA acts by triggering differentiation rather than by exerting a cytotoxic effect on the leukemic clone.
Allogeneic marrow transplantation in patients with chronic myeloid leukemia in the chronic phase: a randomized trial of two irradiation regimens
Authors: Clift RA , Buckner CD , Appelbaum FR , Bryant E , Bearman SI , Petersen FB , Fisher LD , Anasetti C , Beatty P , Bensinger WI
Published: October 2019

A randomized trial was performed to compare two regimens of total body irradiation in patients with chronic myeloid leukemia treated by allogeneic marrow transplantation while in the chronic phase. All patients received cyclophosphamide 120 mg/kg followed by total body irradiation and marrow from HLA-identical siblings. Cyclosporine and methotrexate were used for prophylaxis against acute graft-versus-host disease. Fifty-seven patients were randomized to receive 2.0 Gy fractions of irradiation daily for 6 days and 59 were randomized to receive 2.25 Gy fractions daily for 7 days. The probabilities of relapse at 4 years were 0.25 for the 12.0 Gy group and 0.00 for the 15.75 Gy group (P = .008). The actuarial probabilities of survival and relapse-free survival at 4 years were 0.60 and 0.58 among the patients who received 12.0 Gy compared with 0.66 and 0.66 for those who received 15.75 Gy. The 4-year probabilities of transplant-related mortality were 0.24 and 0.34 respectively (P = .13) while the probability of moderate to severe acute graft-versus-host disease was 0.33 for the 12.0 Gy group and 0.44 for the 15.75 Gy group (P = .15). The lower relapse probability in the patients receiving the higher dose of total body irradiation did not result in improved survival because mortality from causes other than relapse was increased.
Increased circulating colony-stimulating factor-1 in patients with preleukemia, leukemia, and lymphoid malignancies
Authors: Janowska-Wieczorek A , Belch AR , Jacobs A , Bowen D , Padua RA , Paietta E , Stanley ER
Published: October 2019

Recently, several malignant cell types have been reported to express colony-stimulating factor-1 (CSF-1) transcripts; however, the clinical significance of CSF-1 in malignancy has not been investigated. Using a CSF-1 radioimmunoassay, we surveyed concentrations of biologically active CSF-1 in the peripheral blood of 316 patients with malignant and premalignant hematologic disorders; 75 had a myelodysplastic syndrome (MDS), 12 acute myelogenous leukemia (AML), 7 chronic myelogenous leukemia, 21 chronic lymphocytic leukemia (CLL), 106 non-Hodgkin's lymphoma (NHL; of low-, intermediate- and high-grade malignancy), 46 Hodgkin's disease (HD), 46 multiple myeloma (MM), and 3 monoclonal gammopathy of undetermined significance. Controls were 64 healthy subjects. The CSF-1 concentration was correlated with the type of disease, status of the disease, treatment status, and hematologic parameters. CSF-1 concentration was significantly elevated in 83.5% of the patients with active disease, and for each active disease group it was significantly greater (P less than .0001) than in the control. Thus, the high circulating CSF-1 concentration was not associated with a particular malignant phenotype or MDS subtype, but did correlate with the disease activity of both NHL and HD, and the tumor burden in MM, AML, and CLL. There was no correlation of the CSF-1 level with total counts of monocytes or neutrophils in patients with MDS or other malignancies. The cellular basis for the elevated circulating CSF-1 was not investigated. However, the results are consistent with the possibility that the premalignant or malignant cells themselves produce CSF-1 or regulate its production by normal cells.
Hemostatic effect of normal platelet transfusion in severe von Willebrand disease patients
Authors: Castillo R , Monteagudo J , Escolar G , Ordinas A , Magallon M , Martin Villar J
Published: October 2019

Platelet von Willebrand factor (vWF) has been suggested to play an important role in the hemostatic process. Clinical and experimental data indicate that bleeding time (BT) and platelet-vessel wall interaction cannot be normalized unless the defect of platelet vWF is also corrected. We have examined the effect of normal platelet concentrate transfusion 1 hour after cryoprecipitate infusion in five type III von Willebrand disease (vWD) patients. The cryoprecipitate infusion attained normal circulating levels of ristocetin cofactor, vWF antigen, and factor VIII activity. In two patients, cryoprecipitate infusion did not modify the BT (greater than 30 minutes), whereas in the remaining three patients BT was only partially corrected (from greater than 30 to 12, 18, and 21 minutes). However, the immediate platelet transfusion completely corrected the BT in four cases, and in one case it shortened the BT to 8.30 minutes (n = 3 to 8 minutes). In the perfusion study, cryoprecipitate infusion only resulted in a slight increase in platelet deposition (surface coverage range: 2.4% to 11.3%), whereas the platelet concentrate transfusion elicited a more marked improvement (range: 8.2% to 26.4%; P less than .02 v post- cryoprecipitate). These results suggest an important in vivo role of the platelet vWF in supporting platelet-vessel wall interaction. They also give support to the occasional addition of normal platelet transfusion to the cryoprecipitate infusion for the control of serious bleeding episodes resistant to cryoprecipitate in severe vWD patients.
Osteogenic progenitor cells in rat bone marrow stromal populations exhibit self-renewal in culture
Authors: McCulloch CA , Strugurescu M , Hughes F , Melcher AH , Aubin JE
Published: October 2019

Marrow stromal cells are a heterogeneous population, comprising a variety of lineages including osteogenic cells. In the presence of ascorbic acid, sodium beta-glycerophosphate, and dexamethasone, rat bone marrow stromal cells form discrete nodules of mineralized, bonelike tissue. We used nodule formation by rat bone marrow stromal cells to assay for the self-renewal capacity of osteogenic progenitor cell populations. Cultures were subcultured every 5 days up to six times. Osteogenesis was assayed from second to sixth subcultures by counting the number and measuring the areas of mineralized nodules formed in cultures grown with 10(-8) mol/L dexamethasone. Nodule number and area decreased progressively between second and sixth subcultures. Alkaline phosphatase activity associated with individual cells and measured videodensitometrically decreased exponentially between the second and sixth subculture. The number of cells with alkaline phosphatase activity also decreased with progressive subculturing. The proportions of 3H-thymidine-labeled cells after continuous labeling from the beginning of the culture period showed 90% labeling for cells with alkaline phosphatase activity and fibroblastlike cells. Cultures labeled for only the first 3 days exhibited higher labeling of alkaline phosphatase-positive cells than fibroblastlike cells (P less than .05). Cultures that were flash-labeled at the end of the culture period demonstrated low labeling indices for cells with alkaline phosphatase activity and up to 10-fold higher labeling indices for fibroblastlike cells. Separate cultures treated with a cytocidal dose of high specific activity 3H-thymidine did not form nodules. These results indicate that osteogenic progenitor cells or another cell type required for nodules to develop must divide early in culture if nodule formation is to occur, and that osteoprogenitor cells express a limited capacity for self-renewal.
Increased serum levels of granulocyte colony-stimulating factor in patients with severe congenital neutropenia
Authors: Mempel K , Pietsch T , Menzel T , Zeidler C , Welte K
Published: October 2019

Severe congenital neutropenia (SCN), also known as Kostmann Syndrome, is characterized by a maturation arrest of myelopoiesis at the level of promyelocytes with absence of neutrophils in bone marrow (BM) and blood. Hypotheses of the pathophysiology of SCN include (1) defective production of granulocyte colony-stimulating factor (G-CSF), and/or (2) defective response to G-CSF. To exclude defective G-CSF production we tested sera from patients with SCN for the presence of G-CSF using Western blot analysis and NFS-60 proliferation assay. Using these assays we were able to detect increased G-CSF serum levels in SCN patients (150 to 910 pg/mL) as compared with normal controls (between undetectable and 100 pg/mL). These results suggest that patients with SCN have no defect in G-CSF production but a defective response of neutrophil precursors to endogenous G-CSF.
A molecular genetic study of factor XI deficiency
Authors: Hancock JF , Wieland K , Pugh RE , Martinowitz U , Schulman S , Kakkar VV , Kernoff PB , Cooper DN
Published: October 2019

Factor XI deficiency is a rare bleeding diathesis found predominantly in Ashkenazi Jewish kindreds. A recent study of six Jewish patients identified three distinct mutations (Types I, II, and III) in the factor XI gene that were sufficient to fully define the genotypes of the patients. We have investigated 63 patients with factor XI deficiency and find overall allele frequencies of 44% for the type II mutation, 31% for the type III mutation, and 0% for the type I mutation. Therefore, 25% of the mutant factor XI alleles in our sample remain undefined. However, the distribution of mutant alleles is significantly different between Jewish and non-Jewish populations with hitherto undefined mutations accounting for 84% of the disease alleles in non-Jewish patients. Plasma factor XI:C levels were found to differ significantly between different homozygous and compound heterozygous genotypes and the inheritance of the II/III genotype was found to carry an increased risk of the most severe bleeding tendency.
The specific activity of plasminogen activator inhibitor-1 in disseminated intravascular coagulation with acute promyelocytic leukemia
Authors: Sakata Y , Murakami T , Noro A , Mori K , Matsuda M
Published: October 2019

In disseminated intravascular coagulation (DIC) with acute promyelocytic leukemia (APL) in the absence of severe infection, marked fibrinolysis was noted in comparison with normal levels of antithrombin III, which is a major inhibitor of the coagulation system. Increased plasminogen activator inhibitor-1 (PAI-1) antigen levels in plasma from patients with septicemia decreased the ratio of the plasma clot lysis rate induced by an anti-alpha 2-plasmin inhibitor monoclonal antibody to the tissue-type plasminogen activator (t-PA) concentration. This decrease was not as prominent in plasma from patients with DIC, especially those with APL. To explore the character of PAI-1 in these plasmas, we measured the specific activity of PAI-1 by determining the ratio of active PAI-1 antigen to t-PA-unbound PAI-1 antigen. To calculate the amount of active PAI-1 antigen, the amount of t-PA/PAI-1 complex before and after the addition of a fixed amount of t-PA to the sample was measured by a sandwich solid-phase enzyme-linked immunosorbent assay using anti-PAI-1 and anti-t-PA monoclonal antibodies. The assay to measure total PAI-1 antigen used three monoclonal anti-PAI-1 antibodies and had similar sensitivities to free active, latent, vitronectin-bound and t-PA-bound PAI-1. The specific activity of PAI-1 decreased in patients with DIC (43.7% +/- 30.6%) and in DIC cases with APL (10.3% +/- 6.0%) in comparison to patients with septicemia (83.7% +/- 20.2%) or normal controls (85.8% +/- 27.3%). In DIC associated with APL, degraded forms of PAI-1 were detected in plasma by immunoblotting. These results suggest that a decrease in the specific activity of PAI-1 and an increase in secondary fibrinolysis result in a hyperfibrinolytic state in DIC patients with APL.
Clinical significance of soluble CD30 antigen in the sera of patients with untreated Hodgkin's disease
Authors: Gause A , Pohl C , Tschiersch A , Da Costa L , Jung W , Diehl V , Hasenclever D , Pfreundschuh M
Published: October 2019

The soluble form of the CD30 antigen (sCD30), an 88-kd glycoprotein that is released by Hodgkin's-derived cell lines in vitro, can be detected in patients with Hodgkin's lymphoma, adult (HTLV-1+) T-cell leukemia, rare cases of non-Hodgkin's lymphoma, and acute infectious mononucleosis (anti-EBV-IgM+). In a prospective study of 90 consecutive untreated patients with newly diagnosed Hodgkin's disease who were treated according to the protocols of the German Hodgkin Study group, 22% had detectable levels of sCD30 in their serum. sCD30 was only detected in patients with B symptoms (20 of 44 or 45%), and maximum sCD30 levels (88 U/mL) were found in stage IVB. Of 87 patients evaluable for response, sCD30+ patients had significantly lower rates of complete remission (9 of 20 or 45% v 60 of 67 or 90%; P less than .001) and higher rates of progressive disease (9 of 20 or 45% v 6 of 67 or 9%; P less than .001) than CD30+ patients. Similarly, freedom from treatment failure curves were significantly worse for CD30+ patients (P = .0003). sCD30 disappeared after successful treatment, but increased in patients with progressive disease. It was never detected in patients in complete remission or in healthy controls. We conclude that sCD30 is a valuable marker for disease activity and has prognostic significance in Hodgkin's disease.
Possible mechanism of selective killing of myeloid leukemic blast cells by lymphokine-activated killer cells
Authors: Oblakowski P , Bello-Fernandez C , Reittie JE , Heslop HE , Galatowicz G , Veys P , Wilkes S , Prentice HG , Hazlehurst G , Hoffbrand AV
Published: October 2019

Major histocompatibility complex-unrestricted lymphokine-activated killer (LAK) cells have been proposed as therapy for a variety of hematologic malignancies. Because these cells recognize and kill their targets independently of their antigen specific CD3 receptor, it is unclear how they might discriminate between normal and malignant cells. We now propose one such mechanism for the selective killing of myeloid leukemia blasts. While both CD2+ and CD2- activated killer cells may inhibit the clonogenic growth of myeloid leukemia cells, only the CD2+ subset effectively inhibits the growth of normal myeloid (granulocyte- macrophage and granulocyte) progenitors. This difference appears to reflect differential requirements for cell adhesion molecule recognition between normal and malignant progenitor cells. Inhibition of the growth of normal granulocyte-macrophage colonies by CD2+ LAK cells is blocked by antibodies to the CD2-lymphocyte function- associated antigen 3 (LFA-3) (CD58) cell adhesion system. In contrast, these antibodies have no effect on CD2+ LAK-mediated inhibition of malignant cell clonogenic growth. Instead, antibodies to the LFA-1 (CD11a/CD18)-intercellular adhesion molecule 1 (ICAM-1) (CD54) adhesion system reduce inhibition. These differences correspond to differential expression of the CD54 cell adhesion molecule by normal and malignant myeloid progenitor cells because less than 15% of normal CD34 positive cells are CD54+ while greater than 85% of CD34+ acute myeloid leukemia blasts express the CD54 antigen. LFA-3, the ligand for CD2, is strongly expressed by erythrocytes, and these cells competitively inhibit killing of normal but not malignant clonogenic cells in an analogous way to the effects of monoclonal antibody to the CD2-LFA-3 adhesion system. The operation of this effect in vivo may be a basis for selective cytotoxicity by CD2+ LAK against clonogenic myeloid blast cells, and could be exploited further with infusion of appropriate monoclonal antibodies.
Effect of tumor necrosis factor-alpha on the proliferation of leukemic cells from children with B-cell precursor-acute lymphoblastic leukemia (BCP-ALL): studies of primary leukemic cells and BCP-ALL cell lines
Authors: Zhou MX , Findley HW , Ma LH , Zaki SR , Hill T , Hamid M , Hooper WC , Ragab AH
Published: October 2019

The effect of recombinant tumor necrosis factor-alpha (rTNF-alpha) on the primary leukemic blasts and leukemic cell lines derived from children with B-cell precursor acute lymphoblastic leukemia (BCP-ALL) was studied. The proliferation of leukemic cells from the bone marrow of 11 of 13 patients (seven at diagnosis, four in relapse) and from the 697 (BCP-ALL) cell line was significantly inhibited by rTNF-alpha at the lowest dose tested (0.1 ng/mL), as measured by 3H-TdR uptake. The degree of inhibition was variable, ranging from 17% to 78%. Furthermore, a dose-dependent inhibitory effect was observed, with approximately 70% mean inhibition of DNA synthesis detected when cells from 12 of 13 patients were incubated with 100 ng/mL of rTNF-alpha for 3 days. In contrast, rTNF-alpha did not inhibit another BCP-ALL cell line (EU-1/ALL) established recently in our laboratory. Studies indicated that the TNF-alpha gene was expressed by the primary leukemic blasts of one TNF-resistant case in his third relapse and by EU-1 cells. Also, TNF-alpha protein was detected by Western blot analysis and enzyme-linked immunoabsorbent assay in the supernatant of EU-1 cells; this is the first report of TNF production by a BCP-ALL cell lines. The production of TNF-alpha mRNA and protein was not detected in the 697 cell line and in the primary leukemic blasts from six patients (four at diagnosis, two in relapse) whose leukemic cells were inhibited by TNF. The partially purified TNF-alpha obtained from the EU-1 cell line also suppressed the proliferation of TNF-sensitive primary leukemic cells, and this inhibitory activity was abolished by an anti- TNF-alpha specific antibody. Our results demonstrate that TNF-alpha is an inhibitor of in vitro proliferation of BCP-ALL cells from most patients. The TNF-resistant leukemic cells from a few patients and the EU-1 cell line express TNF mRNA, suggesting that the induction of TNF gene expression is associated with the development of TNF resistance.
T-cell receptor tau delta +/CD3+4-8-T- cell acute lymphoblastic leukemias: a distinct subgroup of leukemias in children. A report of five cases
Authors: Alfsen GC , Beiske K , Holte H , Hovig E , Deggerdal A , Sandlie I , Widing E , Slordahl S , Klepper LK , Sizoo W
Published: October 2019

In a 10-year study of T-cell acute lymphoblastic leukemias (T-ALL) in children, we have identified five cases expressing the T-cell receptor tau delta (TCR tau delta). The incidence (26%) of TCR tau delta+T-cell leukemias in our material was high. Clinically, the TCR tau delta+ leukemias represented a distinct subgroup of T-cell leukemias. Mean age at onset of disease, 1.8 years, was remarkably low for mature T-cell leukemias. White blood cell counts were high, lymph node enlargements were discrete, and no mediastinal tumors were seen. Four of five TCR tau delta+ leukemias carried rearrangements of the C tau 2 gene, and transcribed the T-early alpha genetic element.
Phase I/II trial of recombinant human granulocyte-macrophage colony- stimulating factor following allogeneic bone marrow transplantation
Authors: Nemunaitis J , Buckner CD , Appelbaum FR , Higano CS , Mori M , Bianco J , Epstein C , Lipani J , Hansen J , Storb R
Published: October 2019

Forty-seven patients with hematologic neoplasia received recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) by daily 2-hour infusion following allogeneic bone marrow transplantation from HLA-identical sibling donors in a phase I-II dose-escalation trial. Dose levels ranged from 30 to 500 micrograms/m2/d. At doses at or below 250 micrograms/m2/d, toxicity felt to be caused by rhGM-CSF was negligible. However, three of five patients treated with 500 micrograms/m2/d had unacceptable side effects caused by rhGM-CSF. Two different graft-versus-host disease (GVHD) prophylactic regimens were administered. Twenty-seven evaluable patients were administered regimens that did not contain methotrexate (MTX) (Group I) and reached an absolute neutrophil count of 1,000/microL by a median of day 14. In contrast, 18 patients who received GVHD prophylactic regimens containing MTX (Group II) reached an absolute neutrophil count of 1,000/microL on a median of day 20. Patients in Group I had fewer febrile days and, of those discharged, had shorter initial hospitalizations than patients in Group II. The overall incidence of severe acute GVHD (grade 2 or greater) in the rhGM-CSF-treated patients was 28% and was similar to that in historical “good risk” patients who did not receive rhGM-CSF. These preliminary data suggest rhGM-CSF is unlikely to exacerbate GVHD in HLA-identical sibling donor transplants and indicate the need for randomized trials of rhGM-CSF in allogeneic marrow transplant patients.
Mechanisms that regulate the cell cycle status of very primitive hematopoietic cells in long-term human marrow cultures. II. Analysis of positive and negative regulators produced by stromal cells within the adherent layer
Authors: Eaves CJ , Cashman JD , Kay RJ , Dougherty GJ , Otsuka T , Gaboury LA , Hogge DE , Lansdorp PM , Eaves AC , Humphries RK
Published: October 2019

Numerous factors that can influence the proliferation and differentiation in vitro of cells at various stages of hematopoiesis have been identified, but the mechanisms used by stromal cells to regulate the cycling status of the most primitive human hematopoietic cells are still poorly understood. Previous studies of long-term cultures (LTC) of human marrow have suggested that cytokine-induced variations in stromal cell production of one or more stimulators and inhibitors of hematopoiesis may be important. To identify the specific regulators involved, we performed Northern analyses on RNA extracted from human marrow LTC adherent layers, or stromal cell types derived from or related to those present in the adherent layer. These analyses showed marked increases in interleukin-1 beta (IL-1 beta), IL-6, and granulocyte colony-stimulating factor (G-CSF) mRNA levels within 8 hours after treatments that lead to the activation within 2 days of primitive hematopoietic progenitors in such cultures. Increases in granulocyte-macrophage (GM)-CSF and M-CSF mRNA were also sometimes seen. Bioassays using cell lines responsive to G-CSF, GM-CSF, and IL-6 showed significant elevation in growth factor levels 24 hours after IL- 1 beta stimulation. Neither IL-3 nor IL-4 mRNA was detectable at any time. In contrast, transforming growth factor-beta (TGF-beta) mRNA and nanogram levels of TGF-beta bioactivity in the medium were detected at all times in established LTC, and these levels were not consistently altered by any of the manipulations that stimulated hematopoietic growth factor production and primitive progenitor cycling. We also found that addition of anti-TGF-beta antibody could prolong or reactivate primitive progenitor proliferation when added to previously stimulated or quiescent cultures, respectively. Together, these results indicate a dominant negative regulatory role of endogenously produced TGF-beta in unperturbed LTC, with activation of primitive hematopoietic cells being achieved by mechanisms that stimulate stromal cells to produce G-CSF, GM-CSF, and IL-6. Given the similarities between the LTC system and the marrow microenvironment, it seems likely that the control of human stem cell activation in vivo may involve similar variations in the production of these factors by stromal cells.
Flow and the inhibition of prothrombinase by antithrombin III and heparin
Authors: Schoen P , Lindhout T
Published: October 2019

Inhibition of prothrombinase by antithrombin III (ATIII) and heparin was investigated in a continuous-flow system. Phospholipid-coated capillaries, containing phospholipid-bound factor Xa and factor Va, were perfused with 1.0 mumol/L prothrombin and 0.5 nmol/L factor Va. At 25 degrees C and a flow rate of 32 microL/min (shear rate 28 seconds-1) the steady-state rates of prothrombin conversion depended linearly on the surface concentration of prothrombinase up to 2 fmol/cm2. The rate of thrombin generation was 952 +/- 43 (SE) mol/min/mol prothrombinase. When ATIII was included in the perfusate for 10 minutes, the free thrombin concentration at the outlet of the capillary was markedly reduced: a 50% neutralization was obtained at 0.7 mumol/L ATIII. However, the prothrombinase activity was not inhibited, as could be established after a subsequent perfusion with prothrombin and factor Va. At an ATIII concentration typical of normal plasma (2 mumol/L) a slight neutralization of prothrombinase was observed: 10% neutralization following a 10-minute perfusion. During a perfusion with ATIII in the absence of prothrombin, or in its presence with hirudin (2 mumol/L) also included in the perfusate, a more pronounced neutralization of prothrombinase was observed: 40% residual activity was obtained after a 10-minute perfusion. From this observation the suggestion comes forward that thrombin, continuously produced at the surface, consumes ATIII in the boundary layer. In this case the true ATIII concentration in the vicinity of surface-bound prothrombinase will be but a small fraction of the initial ATIII concentration in the bulk fluid. Unfractionated heparin and an ultra-low molecular weight heparin (pentasaccharide) did enhance the ATIII-dependent neutralization of prothrombinase, but to a much lesser extent than observed with small unilaminar phospholipid vesicles as the catalytic sites for prothrombinase assembly. The findings reported here support the notion that regulation of prothrombinase by heparin under in vivo conditions occurs at the stage of its formation, ie, through inhibition of free factor Xa and/or the generation of factor Va, rather than by direct inhibition of the prothrombinase activity.
Purification and characterization of factor VII 304-Gln: a variant molecule with reduced activity isolated from a clinically unaffected male
Authors: O'Brien DP , Gale KM , Anderson JS , McVey JH , Miller GJ , Meade TW , Tuddenham EG
Published: October 2019

Factor VII (FVII) is the plasma serine protease zymogen which, on binding to its cellular receptor tissue factor (TF), initiates blood coagulation. A 47-year-old man with no clinical bleeding tendency was found to have undetectable plasma FVII activity when tested in a one- stage assay using rabbit brain TF, but 0.3 U/mL using recombinant human TF and 1.04 U/mL FVII antigen. Variant FVII purified from his plasma showed an identical migration on sodium dodecyl sulfate-polyacrylamide gel electrophoresis to wild-type zymogen. By enzyme kinetic analysis the Km of the variant using FX as a substrate was 12-fold higher than that of normal FVII. Also, the variant FVII was unable to compete with wild-type FVII for limited rabbit TF binding sites. A ligand blot procedure was used to directly demonstrate reduced binding of recombinant human TF to the variant FVII compared with normal FVII. Genetic analysis of leukocyte DNA showed a G to A mutation in the propositus' gene at codon 304 that results in the substitution of a glutamine for an arginine residue in the catalytic domain of the protease. We conclude that this region of the FVII molecule is important for its function.
Demonstration of antithrombotic activity of glomerular adenosine diphosphatase [published erratum appears in Blood 1991 Oct 15;78(8):2163]
Authors: Poelstra K , Baller JF , Hardonk MJ , Bakker WW
Published: October 2019

We have demonstrated that reduced glomerular adenosine diphosphatase (ADPase) activity within the rat kidney is associated with an increased thrombotic tendency. To establish a possible causal relationship between these intraglomerular events, experiments were conducted to inhibit adenosine diphosphate (ADP) degradation without influencing other glomerular prothrombotic or antithrombotic mechanisms. Concurrently, we studied intraglomerular platelet aggregation. Two ways of selective inhibition of glomerular ADPase activity were applied: (1) by competitive substrates (ie, uridine diphosphate [UDP]), and (2) by the nondegradable ADP analogue ADP-beta-S. Both strategies were used during ex vivo alternate perfusion of kidneys with platelets and ADP (to test intraglomerular thrombotic tendency). Each group (n = 6) received different substrates or a combination of substrates. A significant increase in platelet aggregation was observed in kidneys after perfusion with platelets and ADP together with the competitive substrate UDP as compared to perfusions with platelets and ADP alone (78.5% +/- 9.8% v 27.9% +/- 11.4% glomeruli staining positive for platelets, P less than .005). In contrast, UDP alone had no effect on platelet aggregation. Other nucleoside polyphosphates (guanosine diphosphate and inosine triphosphate) were also effective as competitive substrates in the ex vivo perfusion model (n = 4). None of these substrates was capable of increasing ADP-induced aggregation when studied in vitro. In addition, ADP- beta-S also increased platelet aggregation in the perfusion model as compared with native ADP (P less than .005). These results show that selective reduction of ADP degradation in intact kidneys strongly promotes the intraglomerular proaggregatory condition. It can be concluded that glomerular ADPase exerts potent antithrombotic activity within the normal rat kidney.
In vitro production of granulocyte-macrophage colony-stimulating factor in aplastic anemia: possible mechanisms of action of antithymocyte globulin
Authors: Nimer SD , Golde DW , Kwan K , Lee K , Clark S , Champlin R
Published: October 2019

Various abnormalities of lymphokine production have been described in patients with aplastic anemia. To determine if abnormal production of hematopoietic growth factors could contribute to the process of aplastic anemia we studied the in vitro production of human granulocyte- macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) by phytohemagglutinin (PHA)- and antithymocyte globulin (ATG)- stimulated peripheral blood lymphocytes from 29 patients with aplastic anemia and 15 normal controls. GM-CSF production in response to 1% PHA was seen in nearly all samples (43 of 44) and similar amounts of GM-CSF were produced by patients with aplastic anemia and normal controls. Production of GM-CSF by ATG-stimulated lymphocytes was seen in 7 of 23 patients with aplastic anemia (30%); two of these patients also demonstrated low-level spontaneous production of GM-CSF. Production of GM-CSF in response to ATG was also seen in 2 of 11 normal controls (18%) and barely detectable spontaneous production of GM-CSF was seen in both. Biologically active IL-3 could also be detected in PHA- or ATG- stimulated peripheral blood mononuclear cells in several patients and normal controls. Our results indicate that lymphocytes from patients with aplastic anemia can be stimulated in vitro to produce normal quantities of GM-CSF, suggesting that impaired potential for production of T-cell derived hematopoietic growth factors is unlikely to account for the marrow hypoplasia seen. In several patients overproduction of GM-CSF was observed, consistent with the notion that some patients with aplastic anemia may have circulating activated T cells. We also demonstrate that ATG can stimulate the production of growth factors such as IL-3 and GM-CSF, supporting the role for ATG in stimulating hematopoiesis.
Immunologic correlates of spontaneous lymphocyte proliferation in human T-lymphotropic virus infection
Authors: Prince HE , Lee H , Jensen ER , Swanson P , Weber D , Fitzpatrick L , Doyle M , Kleinman S
Published: October 2019

Previously we showed that mononuclear cells from about half of human T- lymphotropic virus (HTLV)-seropositive persons exhibit spontaneous proliferation in vitro. We sought to determine if proliferation was associated with other immunologic changes characteristic of HTLV infection. The parameters assessed were (1) percentages of lymphocytes expressing CD4 and/or CD25 (interleukin-2 receptor), (2) serum levels of soluble CD25, (3) serostatus for other viruses, (4) anti-HTLV antibody levels, and (5) HTLV type determined by polymerase chain reaction or serologic reactivity with type-specific peptides. The proliferation+ HTLV (PROL+) group, proliferation HTLV (PROL-) group, and control group showed similar percentages of CD4+, CD25+, and CD4+CD25+ lymphocytes; serum levels of soluble CD25 were also similar. Antibodies to cytomegalovirus, hepatitis B core, and hepatitis C were present in similar proportions of PROL+ and PROL+ groups. However, a significant association was found between spontaneous proliferation and anti-HTLV antibody levels; sera from 67% of PROL+ persons, but only 18% of PROL- persons, required dilution to yield absorbance values within the linear range of the anti-HTLV antibody assay. In the PROL+ group, persons whose sera required the most dilution had proliferative responses significantly higher than those whose sera required no dilution. The PROL+ and PROL groups were similar with regard to the relative distribution of HTLV-I and HTLV-II infection. These findings indicate that HTLV-related spontaneous lymphocyte proliferation is related to levels of circulating anti-HTLV antibodies, and characterizes both HTLV-I and HTLV-II infection.
Philadelphia-negative (Ph-) chronic myeloid leukemia (CML): comparison with Ph+ CML and chronic myelomonocytic leukemia. The Groupe Francais de Cytogenetique Hematologique
Authors: Martiat P , Michaux JL , Rodhain J
Published: October 2019

To better understand the Philadelphia-negative (Ph-) chronic myeloid leukemia (CML) and its relationships with Philadelphia-positive (Ph+) CML and chronic myelomonocytic leukemia (CMML), a study was undertaken by the Groupe Francais de Cytogenetique Hematologique. Thirty-five Ph- CML patients were investigated and compared with 55 chronic phase Ph+ CML and 100 CMML patients. There were 12 M-BCR positive (M-BCR+) and 23 M-BCR negative (MBCR+) patients. No clinical or biologic differences were found between Ph+ and Ph-, M-BCR+ patients. In the Ph- group, M- BCR+ and M-BCR- patients differed significantly in age (47.7 +/- 6.6 v 67.0 +/- 6.1 years, respectively; P = .001), leukocytosis (153.4 +/- 135.1 v 58.5 +/- 37.7 10(9)/L, P = .002), relative monocytosis (1.8% +/- 1.2% v 5.6% +/- 1.4%, P = .048), absolute basophilia (8.5 +/- 9.7 v 0.9 +/- 1.5 10(9)/L, P = .001), percentage of immature myeloid precursors (IMP) in peripheral blood (29.0% +/- 9.5% v 15.3% +/- 8.1%, P = .001), and percentage of erythroblasts in bone marrow (BM) (6.5% +/- 3.5% v 14.6% +/- 3.6%, P = .001). Karyotypic abnormalities other than the Ph chromosome occurred in 0 of 12 M-BCR- at diagnosis and 7 of 23 M-BCR- Ph- CML (P = .033). None of the 13 investigated BCR- patients had detectable BCR/ABL transcripts using polymerase chain reaction (PCR) and none had an N-RAS mutation. Cytologic findings showed a marked morphologic difference between M-BCR+ and M-BCR- patients, especially in the monocytic lineage. Dysmyelopoietic features in CMML and M-BCR- patients were very similar, and the differences were of quantitative order only. Using four criteria (monocytosis, percentage of IMP, basophilia, and percentage of erythroblasts in BM), patients could be divided into typical and atypical CML and this classification correlated well with molecular findings. We conclude that, while Ph-, M- BCR+, and Ph+ CML are identical diseases, Ph-, M-BCR- CML, and CMML have many similarities and might be only different aspects of a same entity.
Rapid increase in red blood cell density driven by K:Cl cotransport in a subset of sickle cell anemia reticulocytes and discocytes
Authors: Fabry ME , Romero JR , Buchanan ID , Suzuka SM , Stamatoyannopoulos G , Nagel RL , Canessa M
Published: October 2019

We have previously demonstrated that young normal (AA) and sickle cell anemia (SS) red blood cells are capable of a volume regulatory decrease response (VRD) driven by a K:Cl cotransporter that is activated by low pH or hypotonic conditions. We now report on the characteristics of young SS cells (SS2, discocytes) capable of rapid increase in density in response to swelling. We have isolated cells with high VRD response (H-VRD) and low VRD response (L-VRD) cells by incubation and density- gradient centrifugation under hypotonic conditions. Comparison of these cells in patients homozygous for hemoglobin (Hb)S indicated that H-VRD cells have 91% more reticulocytes (P less than 9 x 10(-9) than L-VRD cells, 25% less HbF (P less than 5.5 x 10(-5), 106% more NEM (N- methylmaleimide)-stimulated K:Cl cotransport activity (P less than 2 x 10(-4), and 86% more volume-stimulated K:Cl cotransport activity (P less than 1.8 x 10(-3). H-VRD and L-VRD cells have similar G-6-PD and Na+/H+ antiport activity. In agreement with the reduced percent HbF in H-VRD cells, F cells (red blood cells that contain fetal Hb) are depleted from the H-VRD population; however, F reticulocytes are enriched in the H-VRD population to the same extent as non-F reticulocytes, which suggests that both F and non-F reticulocytes have a similar initial distribution of volume-sensitive K:Cl cotransport activity but that it may be more rapidly inactivated in F than in S reticulocytes. We find that H-VRD cells consist of 20% reticulocytes (or 79% of all reticulocytes in SS2) and 80% more mature cells. This study demonstrates the role of K:Cl cotransport in determining red blood cell density, the heterogeneity of K:Cl cotransport activity in reticulocytes, and the capacity for rapid change in the density of reticulocytes with high K:Cl cotransport activity. We speculate that the H-VRD population may be more susceptible to generation of dense and irreversibly sickled cells.
Expression of the YB5.B8 antigen (c-kit proto-oncogene product) in normal human bone marrow
Authors: Ashman LK , Cambareri AC , To LB , Levinsky RJ , Juttner CA
Published: October 2019

The c-kit proto-oncogene product is a member of the family of growth factor receptors with intrinsic tyrosine kinase activity. In the mouse c-kit maps to the W locus, which is known to be of central importance in hematopoiesis. Monoclonal antibody (MoAb) YB5.B8, which was raised against peripheral blood blast cells from a patient with acute myeloid leukemia (AML), was recently shown to bind to the extracellular domain of the c-kit product. This antibody does not bind detectably to normal peripheral blood cells and identifies a sub-group of AML patients with poor prognosis. We have used MoAb YB5.B8 to study the expression of c- kit by normal human bone marrow cells by immunofluorescence and flow cytometry, and to isolate multipotential and erythroid colony-forming cells. In a series of 11 normal adult bone marrow specimens, MoAb YB5.B8 bound to 4.0% +/- 1.8% of the cells in the low-density fraction. Dual-labeling experiments were performed with YB5.B8, and CD33, CD34, and CD10 MoAbs. Three populations of cells binding YB5.B8 could be identified based on their pattern of coexpression of the other markers; ie, YB5.B8+/CD34+/CD33-, YB5.B8+/CD34+/CD33+ and YB5.B8+/CD34+/CD33+. These populations had distinctive two-dimensional light scatter characteristics and are likely to correspond to precursor colony- forming cells, colony-forming cells, and maturing mast cells, respectively. No cells binding both YB5.B8 and an MoAb to the early lymphoid marker CD10 were found, implying that most early lymphoid cells do not express c-kit. MoAbs to the c-kit protein should prove valuable in multimarker studies of human hematopoietic stem and progenitor cells. Definition of a reference range of c-kit expression in normal human bone marrow will provide a sound basis for further studies of this marker in diagnosis and prognosis in AML.
Identification of stromal cell precursors in human bone marrow by a novel monoclonal antibody, STRO-1
Authors: Simmons PJ , Torok-Storb B
Published: October 2019

Murine IgM monoclonal antibody STRO-1 identifies a cell surface antigen expressed by stromal elements in human bone marrow (BM). STRO-1 binds to approximately 10% of BM mononuclear cells, greater than 95% of which are nucleated erythroid precursors, but does not react with committed progenitor cells (colony-forming unit granulocyte-macrophage [CFU-GM], erythroid bursts [BFU-E], and mixed colonies [CFU-Mix]). Fibroblast colony-forming cells (CFU-F) are present exclusively in the STRO-1+ population. Dual-color cell sorting using STRO-1 in combination with antibody to glycophorin A yields a population approximately 100-fold enriched in CFU-F in the STRO-1+/glycophorin A+ population. When plated under long-term BM culture (LTBMC) conditions, STRO-1+ cells generate adherent cell layers containing multiple stromal cell types, including adipocytes, smooth muscle cells, and fibroblastic elements. STRO-1+ cells isolated from LTBMC at later times retain the capacity to generate adherent layers with a cellular composition identical to that of the parent cultures. The STRO-1-selected adherent layers are able to support the generation of clonogenic cells and mature hematopoietic cells from a population of CD34+ cells highly enriched in so-called long-term culture-initiating cells. We conclude that antibody STRO-1 binds to BM stromal elements with the capacity to transfer the hematopoietic microenvironment in vitro.
Regulation of jun-B expression by a cyclic AMP (cAMP)-dependent mechanism in human myeloid cells
Authors: Datta R , Nakamura T , Sherman ML , Kufe D
Published: October 2019

The present studies have examined the regulation of the jun-B early response gene by cyclic AMP (cAMP)-dependent signaling pathways. The 2.0-kb jun-B transcript was at low but detectable levels in uninduced human HL-60 myeloid leukemia cells. In contrast, treatment with 1 mmol/L8-bromo-adenosine 3′,5′-cyclic monophosphate (8-Br-cAMP) in the presence of isobutylmethylxanthine, an inhibitor of cAMP-dependent phosphodiesterase, was associated with increases in jun-B transcripts that were maximal by 1 hour and then decreased to near pretreatment levels by 6 hours. Similar findings were obtained with 8–(4- chlorophenylthio)-adenosine 3′,5′-cyclic monophosphate (8-CPT-cAMP) and N6,2′–0-dibutyryladenosine 3′,5′-cyclic monophosphate (dBt-cAMP). jun-B transcripts were also increased with other agents that increase intracellular cAMP levels, such as prostaglandin E2 (PGE2) and forskolin. Moreover, inhibition of cAMP-dependent protein kinase by the isoquinolinesulfonamide H-8 blocked 8-Br-cAMP-induced increases in jun- B expression. The results of nuclear run-on assays demonstrate that treatment of HL-60 cells with PGE2, forskolin, 8-Br-cAMP, and dBt-cAMP is associated with increases in the rate of jun-B transcription. The present findings also demonstrate that the related jun-D gene is similarly regulated by a cAMP-dependent pathway. Taken together, these findings suggest that stimulation of cAMP-dependent protein kinase is involved in the induction of jun gene expression in myeloid leukemia cells.