bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancement of G-CSF–induced stem cell mobilization by antibodies against the β2 integrins LFA-1 and Mac-1
Authors: Velders Gerjo A. , Pruijt Johannes F. M. , Verzaal Perry , van Os Ronald , van Kooyk Yvette , Figdor Carl G. , de Kruijf Evert-Jan F. M. , Willemze Roel , Fibbe Willem E. 
Published: October 2002

AbstractThe β2 integrins leukocyte function antigen-1 (LFA-1, CD11a) and macrophage antigen-1 (Mac-1, CD11b) have been reported to play a role in the attachment of CD34+ cells to stromal cells in the bone marrow. When administered prior to interleukin-8 (IL-8), anti–LFA-1 antibodies completely prevent the IL-8–induced mobilization of hematopoietic stem cells in mice. Here, we studied the role of anti-β2 integrin antibodies in granulocyte colony-stimulating factor (G-CSF)–induced mobilization of hematopoietic progenitor cells. Administration of antibodies against the α chain of LFA-1 or against the α chain of Mac-1 followed by daily injections of G-CSF for more than 1 day resulted in a significant enhancement of mobilization of hematopoietic progenitor cells when compared with mobilization induced by G-CSF alone. Also, the number of late (day 28) cobblestone area–forming cells in vitro was significantly higher after mobilization with anti–LFA-1 antibodies followed by 5 μg G-CSF for 5 days than with G-CSF alone (119 ± 34 days vs 17 ± 14 days), indicating mobilization of repopulating stem cells. Pretreatment with blocking antibodies to intercellular adhesion molecule-1 (ICAM-1; CD54), a ligand of LFA-1 and Mac-1, did not result in an effect on G-CSF–induced mobilization, suggesting that the enhancing effect required an interaction of the β2 integrins and one of their other ligands. Enhancement of mobilization was not observed in LFA-1–deficient (CD11a) mice, indicating that activated cells expressing LFA-1 mediate the synergistic effect, rather than LFA-1–mediated adhesion.
Glycoprotein V: the predominant target antigen in gold-induced autoimmune thrombocytopenia
Authors: Garner Stephen F. , Campbell Kate , Metcalfe Paul , Keidan Jane , Huiskes Elly , Dong Jing-Fei , López José A. , Ouwehand Willem H. 
Published: October 2002

Abstract
Autoimmune thrombocytopenia is generally caused by autoantibodies against glycoprotein (GP) IIb-IIIa or GPIb-IX and occasionally against GPIa-IIa or GPV. By investigating 38 rheumatoid arthritis (RA) patients on gold therapy, 10 with profound thrombocytopenia and 28 nonthrombocytopenic controls, we showed that in all 10 patients with thrombocytopenia, the platelet autoantibodies preferentially targeted GPV but the presence of gold was not required for their reactivity. Elevated levels of platelet-associated IgG (PAIgG) were observed in 8 of the 10 patients in whom the tests were performed. In 5 patients with sufficient autologous platelets, the GPV specificity of PAIgG was confirmed. Tests with GPV transfectants revealed that the antibodies reacted with GPV independent of GPIbα, GPIbβ, or GPIX. Autoantibodies recognizing GPV were not seen in the 28 nonthrombocytopenic control RA patients. Thus, GPV seems to be targeted in gold-induced autoimmune thrombocytopenia.
Analysis of FLT3 length mutations in 1003 patients with acute myeloid leukemia: correlation to cytogenetics, FAB subtype, and prognosis in the AMLCG study and usefulness as a marker for the detection of minimal residual disease
Authors: Schnittger Susanne , Schoch Claudia , Dugas Martin , Kern Wolfgang , Staib Peter , Wuchter Christian , Löffler Helmut , Sauerland Cristina Maria , Serve Hubert , Büchner Thomas , Haferlach Torsten , Hiddemann Wolfgang 
Published: October 2002

Abstract
FLT3 length mutation (FLT3-LM) is a molecular marker potentially useful for the characterization of acute myeloid leukemia (AML). To evaluate the distribution of FLT3-LM within biologic subgroups, we screened 1003 patients with AML at diagnosis for this mutation. FLT3-LM was found in 234 (23.5%) of all patients and thus is the most frequent mutation in AML described so far. Of all positive patients, 165 (70.5%) revealed a normal karyotype. Of the 69 patients with chromosome aberrations, 24 (34.8%) had a t(15;17). The mutation was rare in AML with t(8;21), inv(16) 11q23 rearrangements, and complex karyotypes. FLT3-LM was not distributed equally within different French-American-British (FAB) subtypes and was correlated with a high peripheral blood count in FAB M1, M2, and M4 (P &lt; .0001). In addition, the median age of patients with the mutation was lower (54.9 vs 57.6 years;P = .043), and, at a ratio of 1.36:1 (P = .023), the mutation was more frequent in females than in males. Within the AMLCG study, FLT3-LM was of intermediate prognostic significance. The complete remission rate of 70.3% in patients with FLT3-LM was similar to that (70.4%) in patients without FLT3-LM. Overall survival was not different between patients with or without FLT3-LM. In contrast, patients with FLT3-LM had a significantly shorter event-free survival (7.4 vs 12.6 months;P = .0072) because of a higher relapse rate. Besides the importance of FLT3-LM for biologic and clinical characterization of AML, we show its value as a marker for disease monitoring based on 120 follow-up samples of 34 patients.
Transcriptional regulation of myeloid differentiation primary response (MyD) genes during myeloid differentiation is mediated by nuclear factor Y
Authors: Tjin Tham Sjin Robert M. , Krishnaraju Kandasamy , Hoffman Barbara , Liebermann Dan A. 
Published: October 2002

AbstractTo understand the molecular mechanism by which interleukin-6 (IL-6) regulates myeloid differentiation primary response (MyD) genes at the onset of M1 myeloid differentiation, we used JunB as a representative MyD gene to isolate and characterize IL-6 responsive elements. An IL-6 responsive element was localized between −65 and −52 of the JunB promoter (−65/−52 IL-6RE). By using antibody and oligonucleotide competition assays in electrophoretic mobility shift assay experiments, we have shown that the heterotrimeric transcription nuclear factor Y (NF-Y) complex binds to this element. A dominant-negative form of NF-YA, ectopically expressed in M1 cells, blocked NF-Y binding to the −65/−52 IL-6RE and reduced induction of JunB by IL-6. Furthermore, inhibition of NF-Y binding also reduced MyD gene induction by IL-6 and dampened the IL-6–induced M1 differentiation program. These findings are consistent with the observation that most MyD genes contain intact NF-Y binding motifs in their promoter regions. In contrast to M1 cells, during myeloid differentiation of bone marrow (BM), there was induction of NF-Y binding to the −65/−52 IL-6RE. This induced binding can be attributed to the observed induction of NF-YA protein expression and may reflect the molecular mechanism that couples proliferation to terminal differentiation of normal myeloblasts. Similar to M1 cells, blocking NF-Y binding in BM resulted in a reduction in mature macrophages. It can be concluded that NF-Y plays a role in the transcriptional regulation of MyD genes and is required for optimum myeloid differentiation.
Granulocyte inducer C/EBPα inactivates the myeloid master regulator PU.1: possible role in lineage commitment decisions
Authors: Reddy Venkateshwar A. , Iwama Atsushi , Iotzova Guergana , Schulz Mathias , Elsasser Annika , Vangala Rajani K. , Tenen Daniel G. , Hiddemann Wolfgang , Behre Gerhard 
Published: October 2002

AbstractSeveral transcription factors have been implicated as playing a role in myelopoiesis. PU.1, an ets-family transcription factor, is required for the development of myeloid and lymphoid lineages, whereas the transcription factor CCAAT–enhancer binding protein family member C/EBPα is essential for granulocyte development. We present here the first evidence that C/EBPα blocks the function of PU.1. PU.1 and C/EBPα interact physically and colocalize in myeloid cells. As a consequence of this interaction, C/EBPα can inhibit the function of PU.1 to activate a minimal promoter containing only PU.1 DNA-binding sites. We further demonstrate that the leucine zipper in the DNA-binding domain of C/EBPα interacts with the β3/β4 region in the DNA-binding domain of PU.1 and as a result displaces the PU.1 coactivator c-Jun. Finally, C/EBPα blocks PU.1-induced dendritic cell development from CD34+ human cord blood cells. The functional blocking of PU.1 by C/EBPα could be the mechanism by which C/EBPα inhibits cell fates specified by PU.1 and directs cell development to the granulocyte lineage.
Activated protein C cleaves factor Va more efficiently on endothelium than on platelet surfaces
Authors: Oliver Julie A. , Monroe Dougald M. , Church Frank C. , Roberts Harold R. , Hoffman Maureane 
Published: October 2002

AbstractThe protein C/protein S system is known to regulate thrombin generation in vivo by cleaving factors Va and VIIIa. We have examined the activity of activated protein C in several tissue factor–initiated models of coagulation. We used 4 models: monocytes as the tissue factor source with platelets as the thrombin-generating surface; endothelial cells as the tissue factor source with platelets as the thrombin-generating surface; endothelial cells as both the tissue factor source and the thrombin-generating surface; and relipidated tissue factor with lipid vesicles providing the surface for thrombin generation. With the lipid surface, activated protein C dose-dependently reduced thrombin generation. Similarly, when endothelial cells provided the only surface for thrombin generation, activated protein C dose-dependently decreased thrombin generation significantly. By contrast, whenever platelets were present, activated protein C only minimally affected the amount of thrombin generated. When endothelial cells were the tissue factor source with platelets providing the surface for thrombin generation, activated protein C did increase the time until the burst of thrombin generation but had minimal effects on the total amount of thrombin generated. Activated protein C had essentially no effect on thrombin generation when monocytes were the tissue factor source with platelets providing the surface for thrombin generation. From the studies reported here, we conclude that in vivo, despite the important role of the protein C system in regulating thrombosis, activated protein C does not serve as a primary regulator of platelet-dependent thrombin generation.
Absence of biologically important Kaposi sarcoma–associated herpesvirus gene products and virus-specific cellular immune responses in multiple myeloma
Authors: Brander Christian , Raje Noopur , O'Connor Paula G. , Davies Faith , Davis Jennifer , Chauhan Darminder , Hideshima Teru , Martin Jeff , Osmond Dennis , Kedes Dean H. , Walker Bruce D. , Scadden David T. , Anderson Kenneth C. 
Published: October 2002

Abstract
Kaposi sarcoma–associated herpesvirus (KSHV) has been associated with several diseases, but the association between KSHV and multiple myeloma (MM) remains controversial. To address this issue, we studied patients with MM for the presence of viral RNA transcripts as well as KSHV-specific cellular immune responses. Highly sensitive reverse transcription–polymerase chain reaction assays for detection of viral transcripts of KSHV open reading frame (ORF) 26, ORF72, and ORF74 did not detect viral gene transcripts in long-term cultures of bone marrow stromal cells from 23 patients with MM. Moreover, sensitive assays for KSHV ORF65–specific and ORF73-specific cytotoxic T-lymphocyte (CTL) activity that readily and routinely detect CTLs specific for ORF65 and ORF73 in patients positive for human immunodeficiency virus and KSHV did not show any specific responses in 16 patients with MM, despite the presence of positive Epstein-Barr virus–specific CTLs in all cases. These data therefore do not show a biologically important association between ongoing KSHV infection and MM.
The expression pattern of c-mpl in megakaryocytes correlates with thrombotic risk in essential thrombocythemia
Authors: Teofili Luciana , Pierconti Francesco , Di Febo Annalaura , Maggiano Nicola , Vianelli Nicola , Ascani Stefano , Rossi Elena , Pileri Stefano , Leone Giuseppe , Larocca Luigi Maria , De Stefano Valerio 
Published: October 2002

AbstractUsing immunohistochemistry, we investigated the expression of c-mpl in bone marrow megakaryocytes of 88 patients with essential thrombocythemia (ET), 6 patients with secondary thrombocytosis (ST), and 20 patients with lymphoma (controls). Considering both the pattern of expression and the staining intensity, we identified a uniform and a heterogeneous pattern of c-mplexpression. The uniform pattern was found in all the controls, all the patients with ST, and 28 of the patients with ET, with a strong staining intensity observed in most megakaryocytes (&gt; 80%). In contrast, c-mpl expression was heterogeneous in 60 patients with ET, 18 of whom (30%) presented with thrombosis at diagnosis, a significant difference from patients with a uniform c-mpl pattern (2 of 28; 7%; P = .026). In particular, the overrepresentation of thrombotic complications in patients with a heterogeneous c-mpl expression pattern was found mainly among patients with a significant percentage (10% to 40%) of weakly stained or c-mpl–negative megakaryocytes (heterogeneous-weak pattern; 13 of 30; 43%;P = .002). Accordingly, this pattern was associated with a 6.1-fold increased risk of thrombosis compared with that of patients with a uniform c-mpl pattern. In conclusion, the presence of a heterogeneous pattern of c-mpl distribution in bone marrow megakaryocytes could be a useful diagnostic criterion in the differential diagnosis of thrombocytosis. Furthermore, detection of a significant percentage of weakly stained or c-mpl–negative megakaryocytes can identify patients with a higher risk of thrombosis.
Incidence and outcome of cytomegalovirus infections following nonmyeloablative compared with myeloablative allogeneic stem cell transplantation, a matched control study
Authors: Junghanss Christian , Boeckh Michael , Carter Rachel A. , Sandmaier Brenda M. , Maris Michael B. , Maloney David G. , Chauncey Thomas , McSweeney Peter A. , Little Marie-Térèse , Corey Lawrence , Storb Rainer 
Published: October 2002

Abstract
Nonmyeloablative allogeneic hematopoietic stem cell transplantation (HSCT) is increasingly being explored as therapy in patients who are not eligible for conventional myeloablative HSCT. Whether these transplants are associated with reduced risk of transplantation-related infections is unknown. We analyzed the incidence of posttransplantation cytomegalovirus (CMV) infections in 56 consecutive mycophenolate mofetil (MMF) patients with hematologic malignancies who underwent nonmyeloablative HSCT (TBI, 2Gy, day 0; MMF/cyclosporine after transplantation). In addition, 18 of 56 patients received 30 mg/m2/d fludarabine on days −4 to −2. Most donors were HLA matched and related (93%). Each case patient was matched to 2 controls who were treated by conventional HSCT during the same time period (January 1997 through April 2000). Matching criteria included CMV risk group, HSC source, donor type, age, and underlying diseases. No CMV disease occurred in the low (donor and recipient serologically negative) and intermediate (donor serologically positive and recipient negative) CMV risk groups during the first 100 days. Among cases at high risk for CMV (seropositive recipients), trends to less CMV antigenemia (P = .11), viremia (P = .16), and disease (P = .08) compared with controls were observed; all severe manifestations combined (CMV viremia and disease) were significantly reduced among cases (P = .01). However, by day 365, the overall incidence of CMV disease became similar in both groups. The onset of CMV disease was significantly delayed among case patients compared with controls (median, 130 days versus 52 days; P = .02). It was concluded that CMV disease was significantly delayed in nonmyeloablative cases, but that the overall 1-year incidence was similar to myeloablative HSCT patients. Therefore, nonmyeloablative HSCT patients should receive CMV surveillance beyond day 100 and pre-emptive ganciclovir treatment similar to that of myeloablative HSCT patients.
Leukemic target susceptibility to natural killer cytotoxicity: relationship with BCR-ABL expression
Authors: Baron Frédéric , Turhan Ali G. , Giron-Michel Julien , Azzarone Bruno , Bentires-Alj Mohamed , Bours Vincent , Bourhis Jean Henri , Chouaib Salem , Caignard Anne 
Published: October 2002

AbstractChronic myeloid leukemia is a clonal myeloproliferative expansion of transformed primitive hematopoietic progenitor cells characterized by high-level expression of BCR-ABL chimeric gene, which induces growth factor independence. However, the influence of BCR-ABL expression on cell-mediated cytotoxicity is poorly understood. In the present study, we asked whether BCR-ABL expression interferes with leukemic target sensitivity to natural killer (NK) cell cytolysis. Our approach was based on the use of 2 BCR-ABL transfectants of the pluripotent hematopoietic cell line UT-7 expressing low (UT-7/E8, UT-7/G6) and high (UT-7/9) levels of BCR-ABL. As effector cells, we used CD56bright, CD16−, CD2− NK cells differentiated in vitro from CD34 cord blood progenitors. We demonstrated that BCR-ABL transfectants UT-7/9 were lysed by NK cells with a higher efficiency than parental and low UT-7/E8.1 and UT-7/G6 transfectants. This enhanced susceptibility to lysis correlated with an increase in expression of intercellular adhesion molecule 1 (ICAM-1) by target cells. Treatment of UT-7/9 cells by STI571 (a specific inhibitor of the abl kinase) resulted in a decrease in NK susceptibility to lysis and ICAM-1 down-regulation in target cells. Furthermore, the constitutive activation of nuclear factor-κB (NF-κB) detected in BCR-ABL transfectant UT-7/9, was significantly attenuated when cells were treated by STI571. Interestingly, inhibition of NF-κB activation by BAY11-67082 (a specific NF-κB inhibitor) resulted in down-regulation of ICAM-1 expression and a subsequent decrease in NK-induced killing of UT-7/9 transfectants. Our results show that oncogenic transformation by BCR-ABL may increase susceptibility of leukemic progenitors to NK cell cytotoxicity by a mechanism involving overexpression of ICAM-1 as a consequence of NF-κB activation.
A novel costimulatory signaling in human T lymphocytes by a splice variant of CD28
Authors: Hanawa Haruo , Ma Yong , Mikolajczak Sebastian A. , Charles Matthew L. , Yoshida Tetsuya , Yoshida Ryoko , Strathdee Craig A. , Litchfield David W. , Ochi Atsuo 
Published: October 2002

AbstractWe have characterized a splice variant (isoform) of the human CD28 T cell costimulatory receptor. The nucleotide sequence of this CD28 isoform was identical to that of CD28 in the signal peptide, the transmembrane domain, and the cytoplasmic tail, but it was missing a large segment of the extracellular ligand-binding domain, which is encoded by the second exon. This isoform (CD28i), whose message level exceeded 25% of CD28, was a transmembrane homodimer. CD28i was found noncovalently associated with CD28 and was tyrosine-phosphorylated/PI3-kinase–complexed following the crosslinking of CD28, and the CD28 costimulatory signal was enhanced in T cells expressing CD28i. These data demonstrate that CD28i, via noncovalent association with CD28, plays a role as a costimulatory signal amplifier in human T cells.
Intracellular regulation of tumor necrosis factor–related apoptosis-inducing ligand–induced apoptosis in human multiple myeloma cells
Authors: Mitsiades Nicholas , Mitsiades Constantine S. , Poulaki Vassiliki , Anderson Kenneth C. , Treon Steven P. 
Published: October 2002

AbstractTumor necrosis factor–related apoptosis-inducing ligand (TRAIL, Apo2 ligand) effectively kills multiple myeloma (MM) cells in vitro irrespective of refractoriness to dexamethasone and chemotherapy. Because clinical trials with this anticancer agent are expected shortly, we investigated the signaling pathway of TRAIL-induced apoptosis in MM. We detected rapid cleavage of caspases-8, -9, -3, and -6, as well as the caspase substrates poly(ADP-ribose) polymerase (PARP) and DNA fragmentation factor-45 (DFF45), but not caspase-10, upon TRAIL treatment in sensitive MM cells, pointing to caspase-8 as the apical caspase of TRAIL signaling in MM cells. These phenomena were not observed or were significantly delayed in TRAIL-resistant MM cells, suggesting that resistance may arise from inhibition at the level of caspase-8 activation. Higher levels of expression for various apoptosis inhibitors, including FLICE-inhibitory protein (FLIP), and lower procaspase-8 levels were present in TRAIL-resistant cells and sensitivity was restored by the protein synthesis inhibitor cycloheximide (CHX) and the protein kinase C (PKC) inhibitor bisindolylmaleimide (BIM), which both lowered FLIP and cellular inhibitor of apoptosis protein-2 (cIAP-2) protein levels. Forced expression of procaspase-8 or FLIP antisense oligonucleotides also sensitized TRAIL-resistant cells to TRAIL. Moreover, the cell permeable nuclear factor (NF)–κB inhibitor SN50, which sensitizes TRAIL-resistant cells to TRAIL, also inhibited cIAP2 protein expression. Finally, CHX, BIM, and SN50 facilitated the cleavage and activation of procaspase-8 in TRAIL-resistant cells, confirming that inhibition of TRAIL-induced apoptosis occurs at this level and that these agents sensitize MM cells by relieving this block. Our data set a framework for the clinical use of approaches that sensitize MM cells to TRAIL by agents that inhibit FLIP and cIAP-2 expression or augment caspase-8 activity.
Mechanical properties of rat bone marrow and circulating neutrophils and their responses to inflammatory mediators
Authors: Saito Hajime , Lai Jean , Rogers Rick , Doerschuk Claire M. 
Published: October 2002

AbstractNeutrophils are continuously released from the bone marrow (BM), and this release is accelerated during inflammation. This study compared the mechanical properties of mature neutrophils within the BM and the circulating blood, as well as the role of microtubule rearrangement in the release of neutrophils from the BM in rats. Neutrophils isolated from the BM were stiffer than neutrophils in the circulating blood, using magnetic twisting cytometry. BM neutrophils also contained more F-actin within the submembrane region than circulating neutrophils when examined using confocal microscopy, suggesting that mature quiescent neutrophils within the BM are stiffer than circulating neutrophils because of increased formation of F-actin beneath the plasma membrane. Complement protein 5 fragments or formylmethionyl-leucylphenylalanine (fMLP) induced a stiffening response within 2 minutes that was greater in circulating than in BM neutrophils. This stiffening required F-actin formation within the submembrane region but not microtubule rearrangement in both circulating and BM neutrophils. fMLP-induced shape changes were more pronounced in circulating than in BM neutrophils, which showed fewer and smaller pseudopods and fewer membrane irregularities. In vivo, fMLP induced neutropenia, sequestration of neutrophils within the pulmonary capillaries, and release of neutrophils from the BM. Studies using colchicine demonstrated that rearrangement of microtubules was not required for any of these processes but was required for normal trafficking of neutrophils through the pulmonary capillaries.