bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antigen-primed CD8+ T cells can mediate resistance, preventing allogeneic marrow engraftment in the simultaneous absence of perforin-, CD95L-, TNFR1-, and TRAIL-dependent killing
Authors: Komatsu Masanobu , Mammolenti Michele , Jones Monica , Jurecic Roland , Sayers Thomas J. , Levy Robert B. 
Published: May 2003

AbstractEngraftment failure following allogeneic bone marrow (BM) transplantation is of clinical concern particularly involving T-cell–depleted inoculum and transplantations for aplastic anemia. Immune resistance by lymphoid and natural killer (NK) populations with “barrier” function is well established. Major histocompatibility complex (MHC)–identical marrow allografts were examined to investigate effector pathways in non-NK–mediated resistance. Barrier function was examined in cytotoxic normal and deficient B6 (H-2b) recipients primed to donor minor histocompatibility antigen (MiHA) prior to BM transplantation. Host resistance was sensitively evaluated by colony-forming unit (CFU) assays to directly assess for donor progenitor cell (PC) and peripheral chimerism. B6 host CD8+ T cells but not CD4+ or NK1.1+ cells effected rejection of primitive (CFU-HPP [high-proliferative potential]) and lineage-committed (CFU-IL3/GM [interleukin 3/granulocyte macrophage]) allogeneic donor progenitors. To address complementation by the cytotoxic pathways existing in singly deficient (perforin or FasL) recipients, cytotoxically double (perforin plus FasL) deficient (cdd) recipients were used. Resistance in B6-cdd recipients was comparable to that of wild-type B6 recipients and was also dependent on CD8+ T cells. A “triple” cytotoxic deficient model, involving transplantation of TNFR1−/− (tumor necrosis factor receptor 1) progenitor grafts did not diminish the ability of B6-cdd recipients to reject allografts. Finally, injection of anti-TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) monoclonal antibody (mAb) in B6-cdd recipients also failed to inhibit rejection of TNFR1−/− marrow grafts. In total, these studies demonstrate that CD8+ host T cells can effectively resist MHC-matched MiHA-mismatched donor PCs via alternative effector pathway(s) independent of perforin-, FasL-, TNFR-1–, and TRAIL-dependent cytotoxicity. Therefore, inhibition of these effector pathways in sensitized recipients is unlikely to result in stem cell engraftment following PC allografts.
Continuous absence of metaphase-defined cytogenetic abnormalities, especially of chromosome 13 and hypodiploidy, ensures long-term survival in multiple myeloma treated with Total Therapy I: interpretation in the context of global gene expression
Authors: Shaughnessy John , Jacobson Joth , Sawyer Jeff , McCoy Jason , Fassas Athanasios , Zhan Fenghuang , Bumm Klaus , Epstein Joshua , Anaissie Elias , Jagannath Sundar , Vesole David , Siegel David , Desikan Raman , Munshi Nikhil , Badros Ashraf , Tian Erming , Zangari Maurizio , Tricot Guido , Crowley John , Barlogie Bart 
Published: May 2003

AbstractMetaphase cytogenetic abnormalities (CAs), especially of chromosome 13 (CA 13), confer a grave prognosis in multiple myeloma even with tandem autotransplantations as applied in Total Therapy I, which enrolled 231 patients between 1989 and 1994. With a median follow-up of almost 9 years, the prognostic implications of all individual CAs, detected prior to treatment and at relapse, were investigated. Among all CAs and standard prognostic factors examined prior to therapy, only hypodiploidy and CA 13 (hypo–13 CA), alone or in combination, were associated with shortest event-free survival and overall survival (OS). The shortest postrelapse OS was observed with hypo–13 CA, which was newly detected in 18 of all 28 patients presenting with this abnormality at relapse. Superior prognosis was associated with the absence of any CA at both diagnosis and relapse (10-year OS, 40%). The lack of independent prognostic implications of other CAs points to a uniquely aggressive behavior of hypo–13 CA (present in 16% of patients at diagnosis). With the use of microarray data in 146 patients enrolled in Total Therapy II, overexpression of cell cycle genes distinguished CA from no CA, especially in cases of del(13) detected by interphase fluorescence in situ hybridization (FISH). FISH 13, resulting in a haploinsufficiency of RB1 and other genes mapping to chromosome 13, as well as activation of IGF1R, appears to have an amplifying effect on cell cycle gene expression, thus providing a molecular explanation for the dire outcome of patients with CA 13 compared with those with other CAs.
Inactivation of the human P2Y12 receptor by thiol reagents requires interaction with both extracellular cysteine residues, Cys17 and Cys270
Authors: Ding Zhongren , Kim Soochong , Dorsam Robert T. , Jin Jianguo , Kunapuli Satya P. 
Published: May 2003

Abstract
Human platelets express 2 G protein–coupled nucleotide receptors: the platelet adenosine diphosphate (ADP) receptor coupled to stimulation of phospholipase C (P2Y1) via heterotrimeric guanosine 5-triphosphate (GTP)–binding protein Gq, and the platelet ADP receptor coupled to inhibition of adenylyl cyclase (P2Y12) via heterotrimeric GTP-binding protein Gi. Although these 2 receptors are encoded on the same chromosome and have similar pharmacologic profiles, they have different reactivities toward thiol reagents. The thiol agent p-chloromercuribenzene sulfonic acid (pCMBS) and the active metabolites from antiplatelet drugs, clopidogrel and CS-747, inactivate the P2Y12 receptor and are predicted to interact with the extracellular cysteine residues on the P2Y12 receptor. In this study we identified the reactive cysteine residues on the human P2Y12 receptor by site-directed mutagenesis using pCMBS as the thiol reagent. Cys97Ser and Cys175Ser mutants of the P2Y12 receptor did not express when transfected into Chinese hamster ovary (CHO-K1) cells, indicating the essential nature of a disulfide bridge between these residues. The Cys17Ser, Cys270Ser, and Cys17Ser/Cys270Ser double mutants had similar median effective concentration (EC50) values for ADP and 2-methylthio–ADP (2-MeSADP) when compared with the wild-type P2Y12. Similarly, the median inhibitory concentration (IC50) values for BzATP (2′,3′-O-(4- benzoylbenzoyl) adenosine 5′-triphosphate), an antagonist of the P2Y12 receptor, also did not differ dramatically among these mutants and the wild-type P2Y12receptor. pCMBS inactivated the wild-type P2Y12 receptor in a concentration-dependent manner, whereas it had no effect on the P2Y1 receptor. Finally, pCMBS partially affected the Gi coupling of Cys17Ser or Cys270Ser receptor mutants, but had no effect on Cys17Ser/Cys270Ser P2Y12receptor–mediated inhibition of adenylyl cyclase. These results indicate that, unlike the P2Y1 receptor, which has 2 essential disulfide bridges linking its extracellular domains, the P2Y12 receptor has 2 free cysteines in its extracellular domains (Cys17 and Cys270), both of which are targets of thiol reagents. We speculate that the active metabolites of clopidogrel and CS-747 form disulfide bridges with both Cys17 and Cys270 in the P2Y12 receptor, and thereby inactivate the receptor.
Repopulating defect of mismatch repair–deficient hematopoietic stem cells
Authors: Reese Jane S. , Liu Lili , Gerson Stanton L. 
Published: May 2003

AbstractMismatch repair deficiency is associated with carcinogenesis, increased spontaneous and induced mutagenesis, and resistance to methylating agents. In humans, leukemias and lymphomas arise in the background of mismatch repair deficiency, raising the possibility that hematopoiesis is abnormal as well. To address hematopoiesis in MSH2–/– mice, we collected marrow and performed serial transplantations of these cells, alone or mixed with wild-type cells, into lethally irradiated healthy mice. Transplant recipients were observed or treated with the methylating agent, temozolomide (TMZ). Methylating agent tolerance was evident by the competitive survival advantage of MSH2–/– marrow progenitors compared with wild-type cells after each TMZ exposure. However, serial repopulation by MSH2–/– cells was deficient compared with wild-type cells. In recipients of mixed populations, the MSH 2–/– cells were lost from the marrow, and mice receiving MSH2–/– cells plus TMZ could not be reconstituted in the third passage, whereas all wild-type cell recipients survived. No differences in telomere length, cell cycle distribution, or homing were observed, but an increase in microsatellite instability was seen in the MSH2–/– early progenitor colony-forming unit (CFU) and Sca+Kit+lin–-derived clones. Thus, mismatch repair deficiency is associated with a hematopoietic repopulation defect and stem cell exhaustion because of accumulation of genomic instability.
Neonatal or hepatocyte growth factor–potentiated adult gene therapy with a retroviral vector results in therapeutic levels of canine factor IX for hemophilia B
Authors: Xu Lingfei , Gao Cuihua , Sands Mark S. , Cai Shi-Rong , Nichols Timothy C. , Bellinger Dwight A. , Raymer Robin A. , McCorquodale Stephanie , Ponder Katherine Parker 
Published: May 2003

AbstractHemophilia B is a bleeding disorder resulting from factor IX (FIX) deficiency that might be treated with gene therapy. Neonatal delivery would correct the disease sooner than would transfer into adults, and could reduce immunological responses. Neonatal mice were injected intravenously with a Moloney murine leukemia virus–based retroviral vector (RV) expressing canine FIX (cFIX). They achieved 150% to 280% of normal cFIX antigen levels in plasma (100% is 5 μg/mL), which was functional in vitro and in vivo. Three newborn hemophilia B dogs that were injected intravenously with RV achieved 12% to 36% of normal cFIX antigen levels, which improved coagulation tests. Only one mild bleed has occurred during 14 total months of evaluation. This is the first demonstration of prolonged expression after neonatal gene therapy for hemophilia B in mice or dogs. Most animals failed to make antibodies to cFIX, demonstrating that neonatal gene transfer may induce tolerance. Although hepatocytes from newborns replicate, those from adults do not. Adult mice therefore received hepatocyte growth factor to induce hepatocyte replication prior to intravenous injection of RV. This resulted in expression of 35% of normal cFIX antigen levels for 11 months, although all mice produced anti-cFIX antibodies. This is the first demonstration that high levels of FIX activity can be achieved with an RV in adults without a partial hepatectomy to induce hepatocyte replication. We conclude that RV-mediated hepatic gene therapy is effective for treating hemophilia B in mice and dogs, although the immune system may complicate gene transfer in adults.
Potentiation of dexamethasone-, paclitaxel-, and Ad-p53–induced apoptosis by Bcl-2 antisense oligodeoxynucleotides in drug-resistant multiple myeloma cells
Authors: Liu Qun , Gazitt Yair 
Published: May 2003

Abstract
Overexpression of Bcl-2 in myeloma cells results in resistance to drugs such as dexamethasone (DEX), adenovirus-mediated delivery of p53 (Ad-p53), and paclitaxel (TAX), which work through the intrinsic apoptotic pathway. Bcl-2 antisense oligodeoxynucleotides (Bcl-2-ASO) have been shown to induce apoptosis in cancer cells, as a single agent or, better, in combination with chemotherapy. We hypothesized that down-regulation of Bcl-2 by Bcl-2-ASO will sensitize drug-resistant myeloma cells to undergo apoptosis. In this paper we report a detailed time/dose study of the effect of Bcl-2-ASO on myeloma cells with varying levels of Bcl-2. Treatment of myeloma cells expressing relatively low levels of Bcl-2 with Bcl-2-ASO resulted in a substantial apoptosis concomitant with a substantial depletion of Bcl-2 protein. Maximal apoptosis was observed at 5 to 10 μg/mL Bcl-2-ASO, following 4 days of treatment. Down-regulation of Bcl-2 and apoptosis were time and dose dependent and were sequence specific. In these cell lines, apoptosis was accompanied by activation of caspase-9 and caspase-3 and by release of cytochrome c to the cytosol. In contrast, high Bcl-2–expressing myeloma cells were practically resistant to Bcl-2-ASO. Most important, however, pretreatment of myeloma cells expressing high levels of Bcl-2 with Bcl-2-ASO increased the extent of DEX-, TAX-, and Ad-p53–induced apoptosis from 10%-20% to 70%-90%. Increased apoptosis was accompanied by additional decrease in Bcl-2 protein. Similar results for down-regulation of Bcl-2 and apoptosis were obtained with freshly isolated myeloma cells. These data support development of clinical trials with combinations of Bcl-2-ASO and DEX, TAX, or Ad-p53 in the treatment of refractory myeloma patients.
Transfusion-transmitted cytomegalovirus infection after receipt of leukoreduced blood products
Authors: Nichols W. Garrett , Price Thomas H. , Gooley Ted , Corey Lawrence , Boeckh Michael 
Published: May 2003

AbstractLeukoreduced blood products are reportedly comparable to cytomegalovirus (CMV)–seronegative products for the prevention of transfusion-transmitted CMV (TT-CMV) infection after stem cell (SC) transplantation. To determine if the incidence of TT-CMV was affected by the increasing use of leukoreduced blood products, we followed a prospective cohort of 807 CMV-seronegative SC transplant (SCT) recipients who underwent weekly surveillance using the pp65 antigenemia assay. The incidence of TT-CMV for 2 time periods was recorded: Period 1 (5/94-11/96), when only CMV-seronegative and/or filtered blood products were provided, and period 2 (12/96-2/00), when leukocyte-reduced platelets obtained by apheresis without filtration were also used. The incidence of TT-CMV was higher during period 2 (18/447, 4%) than period 1 (6/360, 1.7%) (P < .05); this was correlated with higher utilization of both filtered and apheresed products from CMV-positive donors in period 2. Multivariable analysis identified filtered red blood cell (RBC) units (but not apheresis platelet products) from CMV-positive donors as the primary predictor of TT-CMV: each additional filtered RBC unit was associated with a 32% increase in the odds for TT-CMV (95% confidence interval [CI]: 8%-61%, P = .006). Pre-emptive therapy with ganciclovir after detection of antigenemia prevented all but one case of CMV disease prior to day 100. CMV-seronegative products may thus be superior to leukoreduced products (particularly filtered RBCs) for the prevention of TT-CMV. In an era of “universal leukoreduction,” the abandonment of CMV-seronegative inventories appears premature, particularly among populations at high risk of CMV disease that do not receive active surveillance.
Increased sensitivity of Fancc-deficient hematopoietic cells to nitric oxide and evidence that this species mediates growth inhibition by cytokines
Authors: Hadjur Suzana , Jirik Frank R. 
Published: May 2003

AbstractFanconi anemia complementation group C (Fancc)–deficient murine bone marrow progenitors demonstrate increased sensitivity to growth inhibition by interferon γ (IFNγ), tumor necrosis factor α (TNFα), and macrophage inflammatory protein 1α (MIP-1α). This property has been proposed as a possible pathogenic factor in the marrow failure seen in Fanconi anemia. Supporting our hypothesis that nitric oxide (NO) production might be a common effector in this sensitivity, we found that cytokine-mediated growth inhibition ofFancc−/− bone marrow cells was prevented by inhibiting NO synthase activity. Interestingly,Fancc−/− hematopoietic cells also exhibited increased growth inhibition on exposure to 2 distinct NO-generating agents, S-nitroso-N-acetyl-D, L-penicillamine (SNAP) and diethylenetriamine nitric oxide adduct (DETA/NO). In keeping with the sensitivity of Fancc−/− cells to IFNγ, inducible nitric oxide synthase (iNOS) levels and nitrite release were both increased following stimulation ofFancc−/− macrophages with this cytokine, either alone or in combination with bacterial lipopolysaccharide. Suggesting a plausible mechanism for the increased expression of iNOS, IFNγ-stimulated Fancc−/− macrophages generated higher levels of phospho-Stat1, a positive regulator ofinos (nos2) gene expression. These observations, while confined to C57BL/6 Fancc−/−hematopoietic cells, raise the possibility that nitric oxide has a role in the pathogenesis of Fanconi anemia.
Monoclonal antibody treatment of mixed cryoglobulinemia resistant to interferon α with an anti-CD20
Authors: Sansonno Domenico , De Re Valli , Lauletta Gianfranco , Tucci Felicia Anna , Boiocchi Mauro , Dammacco Franco 
Published: May 2003

AbstractA controlled study has been carried out to assess the efficacy of rituximab, a chimeric antibody that binds to the B-cell surface antigen CD20, in 20 patients with mixed cryoglobulinemia (MC) and hepatitis C virus (HCV)–positive chronic active liver disease, resistant to interferon α (IFN-α) therapy. They received an intravenous infusion of 375 mg/m2 rituximab once a week for 4 consecutive weeks. Infusion of rituximab had a good safety profile and no severe side effects were reported. Sixteen patients (80%) showed a complete response (CR), characterized by rapid improvement of clinical signs (disappearance of purpura and weakness arthralgia and improvement of peripheral neuropathy), and decline of cryocrit. CR was associated with a significant reduction of rheumatoid factor (RF) activity and anti-HCV antibody titers. Decline of IgG anti-HCV titers in the cryoprecipitates was usually associated with a favorable response (r = 0.81; P < .005). No differences in the dynamics of B-cell depletion and recovery were found between responders and nonresponders. Molecular monitoring of the B-cell response revealed disappearance/deletion of peripheral clones in the responders and great stability in the nonresponders. Rituximab had a deep impact on hepatitis C viremia; HCV RNA increased approximately twice the baseline levels in the responders, whereas it remained much the same in the nonresponders. Twelve (75%) of 16 responders remained in remission throughout the follow-up. The results indicate that rituximab has clinical and biologic activity in patients with HCV+ MC. However, in view of the increased viremia in the responders, additional modes of application and combination of rituximab with other agents need to be investigated.
Chronic lymphocytic leukemia B cells expressing AID display dissociation between class switch recombination and somatic hypermutation
Authors: Oppezzo Pablo , Vuillier Françoise , Vasconcelos Yuri , Dumas Gérard , Magnac Christian , Payelle-Brogard Béatrice , Pritsch Otto , Dighiero Guillaume 
Published: May 2003

Abstract
In B cells, somatic hypermutation (SHM) and class switch recombination (CSR) depend on the activation-induced cytidine deaminase (AID) gene product, although the precise mode of action of AID remains unknown. Because some chronic lymphocytic leukemia (CLL) B cells can undergo CSR without SHM, it constitutes a useful model to dissect AID function. In this work, we have studied AID expression, the presence of mutations in the preswitch μ DNA region, CSR, and the SHM in 65 CLL patients. Our results demonstrate that unmutated CLL B cells can constitutively express AID and that AID expression is associated with the presence of mutations in the preswitch region and in clonally related isotype-switched transcripts. They also demonstrate that in CLL without constitutive AID expression, AID induction on stimulation results in preswitch mutations and the CSR process. Our results show a dissociation between SHM and CSR in CLL and suggest that, in this disease, AID would require additional help for carrying out the SHM process.
PDE4 inhibitors activate a mitochondrial apoptotic pathway in chronic lymphocytic leukemia cells that is regulated by protein phosphatase 2A
Authors: Moon Eun-Yi , Lerner Adam 
Published: May 2003

AbstractChronic lymphocytic leukemia (CLL) cells, but not peripheral blood T cells, undergo apoptosis following treatment with inhibitors of type 4 cyclic nucleotide phosphodiesterase (PDE4), a process that correlates dose dependently with elevation of adenosine 3′,5′-cyclic monophosphate (cAMP) in leukemic cells. We show that treatment of CLL cells with rolipram, a prototypic PDE4 inhibitor, and forskolin, an adenylate cyclase activator, induces mitochondrial depolarization, release of cytochrome c into the cytosol, caspase-9 and -3 activation, and cleavage of poly(adenosine diphosphate [ADP]–ribose)polymerase. Inhibitors of caspase-9, but not caspase-8, block rolipram/forskolin-induced CLL apoptosis. In a subset of CLL patients, B-cell lymphoma 2 (Bcl-2)–associated death promoter homolog (Bad), a proapoptotic Bcl-2 family member that when phosphorylated on specific serine residues is sequestered in the cytosol by 14-3-3, was dephosphorylated at Ser112 following rolipram/forskolin treatment of leukemic cells. Rolipram/forskolin treatment also induced Bad to accumulate in CLL heavy-membrane fractions, consistent with Bad translocation to mitochondria. To determine the mechanism for rolipram/forskolin-induced Bad dephosphorylation, we examined CLL phosphatase activity. Rolipram/forskolin treatment augmented protein phosphatase 2A (PP2A) activity, as well as levels of immunoreactive PP2A catalytic subunit. Treatment of CLL cells with a concentration of okadaic acid (5 nM) that selectively inhibits PP2A, reduced both rolipram/forskolin-induced mitochondrial cytochrome c release and mitochondrial depolarization. Okadaic acid restored Bad Ser112 phosphorylation and Bad association with 14-3-3 in rolipram/forskolin-treated CLL cells. These results suggest that PDE4 inhibitors may induce CLL apoptosis by activating PP2A-induced dephosphorylation of proapoptotic BH3-only Bcl-2 family members such as Bad.
Overexpression of the platelet P2X1 ion channel in transgenic mice generates a novel prothrombotic phenotype
Authors: Oury Cécile , Kuijpers Marijke J. E. , Toth-Zsamboki Emese , Bonnefoy Arnaud , Danloy Sophie , Vreys Ingrid , Feijge Marion A. H. , De Vos Rita , Vermylen Jos , Heemskerk Johan W. M. , Hoylaerts Marc F. 
Published: May 2003

AbstractWe have generated transgenic mice overexpressing the human P2X1 ion channel in the megakaryocytic cell lineage. Platelets from transgenic mice exhibited a gain of P2X1ionotropic activity as determined by more prominent P2X1-mediated Ca2+ influx and platelet shape change. P2X1 overexpression enhanced platelet secretion and aggregation evoked by low doses of collagen, convulxin, or the thromboxane A2 mimetic U46619. In contrast, transgenic platelet responses to adenosine diphosphate (ADP) or thrombin were normal. Perfusing whole blood from transgenic mice over collagen fibers at a shear rate of 1000 seconds−1 resulted in increased P2X1-dependent aggregate formation and phosphatidylserine exposure. Platelet hyperreactivity to collagen was correlated with up-regulated extracellular signal-regulated kinase 2 (ERK2) phosphorylation. Accordingly, the MEK1/2 inhibitor U0126 potently inhibited the collagen-induced aggregation of transgenic platelets when stirred or when perfused over a collagen surface. In a viscometer, shear stress caused potent aggregation of transgenic platelets under conditions in which wild-type platelets did not aggregate. In an in vivo model of thromboembolism consisting of intravenous injection of a low dose of collagen plus epinephrine, transgenic mice died more readily than wild-type mice. Preinjection of U0126 not only fully protected transgenic mice against thrombosis, it also enhanced the survival of wild-type mice injected with a higher collagen dose. Hence, the platelet P2X1 ion channel plays a role in hemostasis and thrombosis through its participation in collagen-, thromboxane A2-, and shear stress–triggered platelet responses. Activation of the ERK2 pathway is instrumental in these processes.