bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proteolytic interactions of factor IXa with human factor VIII and factor VIIIa
Authors: Lamphear BJ , Fay PJ 
Published: October 2019

Abstract
Factor IXa was shown to inactivate both factor VIII and factor VIIIa in a phospholipid-dependent reaction that could be blocked by an antifactor IX antibody. Factor IXa-catalyzed inactivation correlated with proteolytic cleavages within the A1 subunit of factor VIIIa and within the heavy chain (contiguous A1-A2-B domains) of factor VIII. Furthermore, a relatively slow conversion of factor VIII light chain to a 68-Kd fragment was observed after prolonged incubation. Sites of cleavage were identified within the A1 domain at Arg336-Met337 and within the factor VIII light chain at Arg1719-Asn1720. Factor IXa failed to cleave isolated factor VIII heavy chains, yet cleaved isolated factor VIII light chain. In addition, the purified A1/A3-C1-C2 dimer derived from factor VIIIa was a substrate for factor IXa; however, cleavage of the A1 subunit occurred at less than 30% the rate of cleavage of A1 in trimeric factor VIIIa. These data suggest that factor VIII light chain contributes to the binding site for factor IXa and also support a role for a heavy chain determinant located within the A2 subunit in the association of factor VIIIa with factor IXa. Furthermore, the capacity of factor IXa to proteolytically inactivate its cofactor, factor VIIIa, suggests a mode of regulation within the intrinsic tenase complex.
Modulation of myeloid proliferation and differentiation by monoclonal antibodies directed against a protein that interacts with the interleukin-3 receptor
Authors: Tweardy DJ , Morel PA , Mott PL , Glazer EW , Zeh HJ , Sakurai M 
Published: October 2019

Abstract
Hematopoietic cells can be transformed through the acquisition of autocrine growth factor production. Because of their ability to inhibit autocrine growth, antibodies directed against the growth factor or its receptor may have therapeutic potential. However, these agents may also inhibit normal cell development. We have developed two monoclonal antibodies, 4G8 and 2F2, directed against a protein of 110 to 150 Kd that interacts with the interleukin-3 (IL-3) receptor (R) complex. These antibodies inhibit IL-3-induced proliferation of nonleukemic and leukemic IL-3-dependent cell lines, as well as the autonomous growth of WEHI-3B in vitro and in vivo. These results suggest the possibility that anti-IL-3R antibodies may be useful in the treatment of some leukemias. However, the effect of anti-IL-3R antibodies on normal myeloid development in vitro has not been examined. We examined the effect of 4G8 and 2F2 on the growth in vitro of colony-forming unit granulocyte-macrophage (CFU-GM) colonies induced by IL-3, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), and macrophage-CSF (M-CSF). Our results show that while 4G8 and 2F2 inhibited CFU-GM colony formation induced by IL-3, they augmented colony formation induced by the other hematopoietins. 4G8 and 2F2 also enhanced G-CSF-induced proliferation of 32Dc13 and GM-CSF-induced proliferation of PT18, confirming that the effect on CFU-GM was a direct effect. Finally, 4G8 and 2F2 inhibited G-CSF-induced differentiation of 32Dc13, similar to low levels of IL-3; yet, neither 4G8 nor 2F2 blocked binding of G-CSF to its receptor. These results indicate that, in the absence of IL-3 and in the presence of other hematopoietins, 4G8 and 2F2 can function as weak IL-3 agonists. These studies suggest that antibodies such as 4G8 and 2F2, directed against components of the IL-3R, could potentially augment myeloid growth in vivo, rather than inhibit myeloid growth.
Vascular cell adhesion molecule-1 expressed by bone marrow stromal cells mediates the binding of hematopoietic progenitor cells
Authors: Simmons PJ , Masinovsky B , Longenecker BM , Berenson R , Torok-Storb B , Gallatin WM 
Published: October 2019

Abstract
Human bone marrow-derived CD34+ cells were analyzed for the expression of the beta 1-family of integrin adhesion molecules. Integrin alpha 4 beta 1 was consistently expressed by greater than 90% of CD34+ cells, including essentially all assayable granulocyte-macrophage colony- forming cells (CFU-GM) and erythroid bursts (BFU-E) as shown by fluorescence-activated cell sorting studies. Adhesion of highly enriched CD34+ cells to cultured allogeneic marrow stromal cells was largely inhibited both by monoclonal antibody to alpha 4 beta 1 and to vascular cell adhesion molecule-1 (VCAM-1), a ligand for alpha 4 beta 1. VCAM-1 was found to be expressed by bone marrow stromal elements in vitro both constitutively at low level and at high levels after treatment with cytokines. Induction of VCAM-1 was cytokine- and time- dependent with maximum levels being obtained after 4 hours of exposure to a combination of interleukin-4 and tumor necrosis factor-alpha. Cytokine-induced stromal cells bound threefold higher numbers of CFU-GM and BFU-E, this increase being abrogated by anti-alpha 4 beta 1 and anti-VCAM-1 antibodies. In addition, the adhesion to stroma of more immature progenitors, the long-term culture initiating cells, also occurred through an alpha 4 beta 1/VCAM-1-dependent mechanism. These studies identify an adhesion mechanism of potential importance in the localization of primitive progenitors within the hematopoietic microenvironment.
Effects of synergistic cytokine combinations, low oxygen, and irradiated stroma on the expansion of human cord blood progenitors
Authors: Koller MR , Bender JG , Papoutsakis ET , Miller WM 
Published: October 2019

Abstract
Expansion of hematopoietic progenitor cells in the mononuclear cell (MNC) fraction of human cord blood was evaluated under atmospheres containing reduced (5%) and normal (20%) oxygen tensions. Cells were cultured with synergistic cytokine combinations in suspension (without stroma) and on irradiated bone marrow stroma. Addition of interleukin (IL)-3 and IL-6 (IL-3/IL-6) provided a greater expansion of both total and progenitor cells than IL-1 and IL-3 (IL-1/IL-3). IL-3/IL-6 maintained a higher level of progenitors throughout the 8-week culture period, whereas progenitors disappeared earlier from cultures with IL- 1/IL-3. This indicates that an earlier cell type was affected by IL- 3/IL-6, and/or that IL-3/IL-6 favored self-renewal while IL-1/IL-3 induced differentiation. Reduced oxygen tension enhanced the productivity of these long-term hematopoietic cultures (LTHC) under all conditions tested. In suspension cultures, reduced oxygen increased cumulative total cell production by 125% and 167%, and cumulative progenitor production by 68% and 21%, with IL-1/IL-3 and IL-3/IL-6, respectively. The presence of irradiated stroma increased cumulative progenitor cell production almost threefold in cultures without cytokines. In cultures with cytokines, the beneficial effect of stroma was less significant, but was greater under 20% O2 than 5% O2. Cultures under 5% O2 provided more progenitors and often maintained progenitors for 1 to 2 weeks longer than those under 20% O2. To quantitate more precisely the shift in cell populations induced by IL-3/IL-6 and stroma in cultures under 5% O2, flow cytometry analysis was used. By week 3, the addition of IL-3/IL-6 stimulated a 15-fold and 25-fold expansion of promyelocytes (CD15+CD11b-) in suspension and stromal cultures, respectively. Addition of IL-3/IL-6 also increased mature granulocyte (CD15hiCD11b+) and monocyte (CD15loCD11b+) numbers, while no effect was seen on T-(CD3+) or B- (CD19+) lymphocytes. Endogenous production of IL- 6 was significantly higher under 5% O2 in both suspension and stromal cultures, and IL-6 production was increased threefold by the addition of IL-1/IL-3. Very little IL-1 beta was produced in these cultures, and endogenous IL-3 and tumor necrosis factor (TNF)-alpha were undetectable by enzyme-linked immunosorbent assay (ELISA) analysis.
Distribution and phenotype of Epstein-Barr virus-harboring cells in Hodgkin's disease
Authors: Herbst H , Steinbrecher E , Niedobitek G , Young LS , Brooks L , Muller-Lantzsch N , Stein H 
Published: October 2019

Abstract
Distribution and phenotype of Epstein-Barr virus (EBV)-harboring cells were determined in Hodgkin's disease (HD) biopsies by in situ hybridization with [35S]-labeled RNA probes specific for the small EBV- encoded nuclear RNAs, EBER1 and EBER2, in some instances preceded by immunohistology for CD20, CD30, CD45RO, and CD68 antigens, the T-cell receptor beta-chain, and latent membrane antigen (LMP) of EBV. Twenty- three of 46 HD cases displayed EBER transcripts in all Hodgkin and Reed- Sternberg (H-RS) cells, and 18 of these cases showed LMP expression exclusively in neoplastic cells. EBER+ small reactive cells were present in 39 cases in low numbers, and in three cases in abundance. Thus, presence of H-RS cells with or without LMP expression was not accompanied by an unrestricted proliferation of reactive EBER+/LMP- lymphoid cells in the majority of HD patients. Simultaneous in situ hybridization with [35S]-labeled immunoglobulin light chain (IgLC) gene probes and nonisotopically labeled EBER probe showed a phenotype of mature B lymphocytes and a polyclonal composition for a large proportion of the EBER+ small cells. However, in contrast to noninfected cells, CD20 expression was not detectable in many of these cells, which may indicate downregulation of certain differentiation antigens in latently EBV-infected small lymphoid cells in vivo.
2-Chlorodeoxyadenosine: an active agent in the treatment of cutaneous T- cell lymphoma
Authors: Saven A , Carrera CJ , Carson DA , Beutler E , Piro LD 
Published: October 2019

Abstract
Cutaneous T-cell lymphomas are disfiguring malignant lymphoproliferative disorders for which standard therapy has been principally palliative. 2-Chlorodeoxyadenosine (2-CdA), a new purine analogue resistant to degradation by adenosine deaminase that has substantial activity against lymphoid neoplasms, was administered to 16 patients with cutaneous involvement by T-cell lymphoma. All patients had failed topical treatment modalities and/or systemic therapies. Fifteen patients were evaluable; one patient was not evaluable due to incomplete therapy and follow-up. The overall response rate was 47%. Three of 15 patients (20%) achieved complete responses and four of 15 patients (27%) achieved partial responses. The median duration of response was 5 months. One patient remains in unmaintained complete remission at 52+ months. Therapy was well tolerated. Myelosuppression was the principal toxicity encountered, occurring in 8 of 15 (53%) patients. 2-CdA is an effective new agent for the treatment of cutaneous T-cell lymphoma and warrants further study both as a single agent and in combination regimens.
Interleukin-3 regulates the activity of the LYN protein-tyrosine kinase in myeloid-committed leukemic cell lines
Authors: Torigoe T , O'Connor R , Santoli D , Reed JC 
Published: October 2019

Abstract
The lymphokine interleukin-3 (IL-3) promotes the growth and survival of immature hematopoietic cells. Previous studies have shown that IL-3 induces rapid increases in protein-tyrosine kinase (PTK) activity in IL- 3--dependent cells. Unlike some other hematopoietic growth factor receptors (eg, c-fms and c-kit), however, the known subunits of the IL- 3 receptor (IL-3R) lack intrinsic kinase activity. Recently, it was reported that the IL-2R (whose p75 beta-subunit shares sequence homology with a known murine IL-3R subunit and a common beta-subunit of the human IL-3R and granulocyte-macrophage colony-stimulating factor [GM-CSF] receptors) can physically associate with and regulate the activity of the SRC-family PTK, p56-LCK. Because most IL-3--dependent cells contain p53/56-LYN, but not p56-LCK, we explored the effects of IL-3 on the activities of LYN and other SRC-like PTKs in two human leukemic cell lines, AML-193 and TALL-101, which are phenotypically myeloid, and whose in vitro growth is dependent on IL-3. These cells expressed four of the eight known SRC-family proto-oncogenes: lyn, fyn, yes, and hck. When these factor-dependent leukemic cell lines were deprived of lymphokine to achieve cellular quiescence and then restimulated with IL-3, rapid increases (detectable within 1 minute and maximal by 10 minutes) were observed in the activity of the p53/56-LYN kinase, as assessed by in vitro kinase assays. In contrast, no alteration in the activities of other SRC-family PTKs present in these cells was detected after restimulation with IL-3 under the same conditions. This effect of IL-3 reflected an increase in the specific activity of the LYN kinase, because levels of the 53-Kd and 56-Kd LYN proteins were unaltered by IL-3 stimulation, as assessed by immunoblotting. Furthermore, the magnitude of these inducible increases in LYN kinase activity was dependent on the concentration of IL-3, and correlated with IL-3--induced proliferation. The IL-3--induced upregulation of LYN kinase activity may be mediated by the 120-Kd common subunit of the human IL-3 and GM-CSF receptors, because GM-CSF also stimulated marked increases in the activity of the LYN kinase, whereas granulocyte-CSF (G-CSF) did not, despite inducing cellular proliferation. These observations provide the first example of an IL-3-- regulable PTK, and strongly suggest that the p53/56-LYN kinase participates in early IL-3--initiated signalling events, at least in some human leukemic cell lines.
Stem cell factor induction of in vitro murine hematopoietic colony formation by "subliminal" cytokine combinations: the role of "anchor factors"
Authors: Lowry PA , Deacon D , Whitefield P , McGrath HE , Quesenberry PJ 
Published: October 2019

Abstract
The high levels of hematopoietic growth factors required for in vitro and in vivo activity raise questions as to their role in normal hematopoietic maintenance. We hypothesize that the use of combinations of cytokines to stimulate hematopoietic progenitors might allow individual factors to exert their influence at lower, more physiologically relevant concentrations. Growth factor combinations were assessed by their ability to stimulate both total colonies and high proliferative potential colony-forming cells (HPP-CFC), an early murine hematopoietic progenitor, in double-layer agar cultures. Very- low-level combinations of colony-stimulating factor (CSF)-1, granulocyte CSF (G-CSF), granulocyte-macrophage CSF (GM-CSF), interleukin (IL)-1 alpha, and IL-3 had little or no clonogenic capacity. Plateau levels of rr stem cell factor (rrSCF), a c-kit ligand, used alone also had negligible clonogenic capacity, but when combined with the low-level combination of the other five factors produced total colony and HPP-CFC growth approaching that produced by all factors at plateau levels. Delayed addition experiments suggest that this effect may represent sequential activity of SCF and the other factors. We propose a model of the normal hematopoietic microenvironment in which SCF at locally high concentration on the stromal cell surface “anchors” the hematopoietic stem cell's response to multiple other cytokines at physiologically relevant levels.
Interleukin-2-activated natural killer cells can support hematopoiesis in vitro and promote marrow engraftment in vivo
Authors: Murphy WJ , Keller JR , Harrison CL , Young HA , Longo DL 
Published: October 2019

Abstract
Purified natural killer (NK) cells were obtained from mice with severe combined immune deficiency (SCID) to ascertain their effect on hematopoiesis. When activated and propagated with recombinant human interleukin-2 (rhIL-2) in vitro, SCID spleen cells maintained a phenotypic and lytic spectrum consistent with a pure population of activated NK cells. When added with syngeneic bone marrow cells (BMC) in soft agar, the activated NK cells could support hematopoietic growth in vitro without the addition of exogenous hematopoietic growth factors. However, when syngeneic BMC were added along with cytokines to produce optimal growth conditions, the addition of NK cells was then inhibitory for hematopoietic colony formation. Antibodies to interferon- gamma (IFN-gamma) partially reversed the inhibitory effects. Supernatants from the NK-cell cultures could also exert these effects on hematopoiesis, although to a lesser extent. Analysis of the NK cell RNA demonstrated that activated NK cells express genes for hematopoietic growth factors such as granulocyte-macrophage colony- stimulating factor (GM-CSF), granulocyte CSF (G-CSF), and IL-1 beta. The NK cells were also found to express IFN-gamma, transforming growth factor-beta 1 (TGF-beta 1), and tumor necrosis factor-alpha (TNF-alpha) mRNA. Analysis of the NK-cell supernatants using factor-dependent myeloid progenitor cell lines showed that the NK cells were producing G- CSF and growth-promoting activity that could not be attributed to IL-1, IL-3, IL-4, IL-5, IL-6, GM-CSF, G-CSF, macrophage CSF (M-CSF), or stem cell factor. The transfer of activated NK cells with BMC into lethally irradiated syngeneic mice resulted in greater BMC engraftment in the recipients. Thus, these results using a pure population of activated NK cells indicate that when activated, these cells can produce a variety of growth factors for hematopoiesis and exert significant hematopoietic growth-promoting effects in vivo.
Plasma crosslinked fibrin polymers: quantitation based on tissue plasminogen activator conversion to D-dimer and measurement in normal and patients with acute thrombotic disorders
Authors: Kornberg A , Francis CW , Marder VJ 
Published: October 2019

Abstract
Plasma crosslinked fibrin polymers (XLFP) are formed as a result of in vivo hemostatic activation and are elevated in thrombotic disease. We have investigated the plasmic degradation of plasma XLFP in vitro to provide information regarding the pattern of crosslinking and the composition of degradation products. Plasma XLFP were identified by sodium dodecyl sulfate (SDS)-agarose electrophoresis and Western blotting and quantitated by gel scanning. D-dimer was measured by enzyme-linked immunosorbent assay and the results were verified by SDS- polyacrylamide gel electrophoresis and Western blotting of the digests. Complete degradation of XLFP occurred only after supplementation of plasma with plasminogen (5 U/mL) and incubation with recombinant tissue plasminogen activator (rt-PA), indicating that the normal plasma plasminogen concentration limits plasmic degradation in vitro. Gel electrophoresis showed that the principal terminal degradation products of XLDP were fragments D, DD, and E, indicating that crosslinking occurred primarily through gamma chain dimers. After adding a low concentration of thrombin to plasma in vitro, XLFP increased progressively before clotting, and the concentration correlated with the increase in the D-dimer concentration after degradation (r = .98). Plasma XLFP and D-dimer concentrations in plasmic digests were significantly elevated in patients with stroke (150 +/- 83 micrograms/mL and 88 +/- 32 micrograms/mL), myocardial infarction (217 +/- 110 micrograms/mL and 84 +/- 30 micrograms/mL), and venous thrombosis (187 +/- 80 micrograms/mL and 86 +/- 19 micrograms/mL) compared with normals (28 +/- 12 micrograms/mL and 25 +/- 7 micrograms/mL). There was a strong correlation between the plasma concentration of XLFP and the D-dimer immunoreactivity of plasma after plasmic degradation (r = .87). The results indicate that XLFP in plasma are crosslinked primarily through gamma chains and degrade to fragment DD with plasminogen activation. Also, the immunoreactivity of in vitro plasmic digests of plasma reflects the concentration of XLFP and may provide a useful indirect measure of in vivo hemostatic activation in patients with thrombotic disease.
Interferon-gamma gene expression in human B-cell lines: induction by interleukin-2, protein kinase C activators, and possible effect of hypomethylation on gene regulation
Authors: Pang Y , Norihisa Y , Benjamin D , Kantor RR , Young HA 
Published: October 2019

Abstract
Human interferon-gamma (IFN-gamma) is an important immunomodulatory protein produced predominantly by T cells and large granular lymphocytes (LGLs). Whereas large amounts of data have been accumulated regarding IFN gamma gene expression in these two cell types, little information about IFN gamma expression in other cell types exists. In this study, we have analyzed the production of IFN gamma by the Epstein- Barr virus (EBV)-positive B-cell line, JLP(c), derived from a patient with Burkitt's lymphoma, and another human B-cell line, PA682BM-1, which was derived from an acquired immunodeficiency syndrome patient. Southern blot analysis indicates the presence of an Ig heavy chain gene rearrangement, but no rearrangement of the T-cell receptor beta chain gene or IFN gamma gene in these B-cell lines. Both cell lines were found to express surface IgD and other B-cell surface markers, thus confirming their B-cell lineage. Analysis for surface Ig, cytoplasmic Ig, and secreted Ig indicates that the two cell lines are in relatively early stages of the B-cell differentiation pathway. We now report that PA682BM-1 can be triggered by the protein kinase C (PKC) activators, phorbol 12-myristate 13-acetate (PMA) and (-)Indolactam-v, to secrete IFN gamma, whereas JLP(c) cells spontaneously produce low levels of IFN gamma that can be enhanced by PKC activators and interleukin-2 (IL-2). After activation of the cell lines with IL-2, (-)Indolactam-v, and PMA, increases in cytoplasmic messenger RNAs (mRNAs) of IFN gamma and the IL- 2 receptor chains were also observed. The induction of IFN gamma mRNA and protein by IL-2 was completely blocked by a monoclonal antibody to IL-2 receptor p75 (beta chain), but not by the monoclonal antibody to p55 (alpha chain). Analysis of IFN gamma genomic DNA indicates that the gene is not amplified, but that hypomethylation in the 5′ noncoding region of the IFN gamma gene has occurred in the B-cell line from the Burkitt's lymphoma patient that spontaneously produces IFN gamma. This finding suggests that the methylation state of the promoter region may play an important role in the control of IFN gamma gene expression in B cells.
Absence of immunoglobulin variable region hypermutation in a large cell lymphoma after in vivo and in vitro propagation
Authors: Stiernholm N , Kuzniar B , Berinstein NL 
Published: October 2019

Abstract
Several genetic mechanisms have been shown to diversity the expressed antibody repertoire of committed B lymphocytes. These include somatic hypermutation, V gene replacement, and ongoing gene rearrangement. These mechanisms may be operational at discrete points in the B-cell differentiation pathway and may generate idiotypic diversity in various malignant B-cell tumors. Hypermutation of the Ig variable region has been shown to occur in follicular lymphoma, but not in pre-B cell acute lymphoblastic leukemia, Burkitt's lymphoma, chronic lymphocytic leukemia, or myeloma. To study hypermutation in a large cell lymphoma, we use a polymerase chain reaction-based approach, employing consensus VH and JH primers, to clone and sequence rearranged Ig heavy chain variable regions. Neither tumor cells immortalized in rescue fusions nor idiotypic variants of a tumor-derived cell line generated through ongoing lambda light chain gene rearrangements show any significant number of variable region mutations. Thus, at the in vivo stage of B- cell differentiation from which this large cell lymphoma arose, Ig variable region hypermutation was not occurring, nor did it occur during propagation in vitro of these tumor cells. Thus, the window of hypermutation in malignant B-cell tumors is more precisely defined, which may have clinical implications for diagnostic and therapeutic approaches directed at the Ig variable region.