bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impaired Expression of the DNA Repair Factor DDB2 in Human Myeloid Leukemias.
Authors: Takimoto Rishu , Kato Junji , Takada Koichi , Matsunaga Takuya , Niitsu Yoshiro 
Published: October 2019

Abstract
Recent studies have suggested that chromosomal deletions might represent a mechanism of inactivation of DNA repair system in various hematological malignancies, including myeloid leukemias. However, the precise mechanisms remain unclear. Damaged DNA binding protein-2 (DDB2), a DNA repair factor induced by tumor suppressor p53, plays an important role in the nucleotide excision repair of UV-damaged DNA. Despite frequent mutations of p53 in human leukemic cells, the role of DDB2 on the leukemogenesis is unkown. In this study, we examined expression of DDB2 mRNA in four human myeloid leukemia cell lines (K562, KG1, HL60, and MEG01) and in fresh leukemic cells obtained from 4 patients with myeloid leukemias. In all leukemia cells, expression of DDB2 mRNA was remarkably decreased as compared to that of CD34 cells We then assayed DDB2-dependent DNA repairing activity in the leukemic cells using specific antibodies against photoproducts, and found that DNA repairing activity was reduced. When a plasmid encoding DDB2 gene (pCV-DDB2) was transduced into K562 cells, the DNA repairing activity was significantly restored. Finally we tested the expression of DDB2 mRNA in five myeloid leukemias obtained from patients, and found loss of DDB2 expression in four patients. These results suggested that in human myeloid leukemias, suppression of DDB2 expression may contribute to accumulation of gene mutation through the dysfunction of DNA repair.
An Alternative Growth Factor for Hematopoietic Stem Cells and Megakaryocytopoiesis.
Authors: Yang Mo , Li Karen Kwar Har , Chuen C.K.Y. , Chick Ki Wai , Pong Nga Hin , Fok Tai Fai 
Published: October 2019

Abstract
The role of serotonin (5-hydroxytryptamine, 5-HT) on the regulation of blood stem cell proliferation and thrombopoiesis has not been recognized until 1996, when we reported that serotonin has a mitogenic effect on murine megakaryocytopoiesis via 5-HT2 receptors (Yang et al, Blood Coagul Fibrin 1996). Our study also indicated that the uptake ability of serotonin is well established in human megakaryoblasts (Yang et al, Int J Hematol, 1996). 5-HT 2A, 2B and 2C receptors were identified on human megakaryocytes and serotonin also promoted human megakaryocytopoiesis via these receptors (Yang et al, Blood, 2001; 2002 suppl). Thus, we established a new concept that serotonin is a growth factor for megakaryocytopoiesis (Yang et al, Blood, 2003 suppl). We further investigated the role of serotonin on human hematopoietic stem cells, bone marrow stromal cells and platelet formation. Serotonin (200 nM) significantly enhanced TPO, SCF plus FL -induced the ex vivo expansion of CD34+ cells, CD34+38- cells, CD41+61+ cells, CFU-GEMM and CFU-MK from cord blood CD34+ cells (MACS) (n=25) at day 8 (P<0.001). More significantly, serotonin enhanced the engraftment of human CD45+ cells, and their myeloid subsets CD33+ (p=0.05) in NOD/SCID mice. The expression of 5-HT 2A, 2B and 2C receptors was detectable in fresh CD34+ cells by RT PCR. These 5-HT receptors were further demonstrated in 1% of CD34+ cells by FACS. Our data also demonstrated that serotonin significantly stimulated the proliferation of bone marrow stromal cells in a dose-dependent manner (10–500 nM) in human CFU-F assay. A maximum stimulation was obtained at 200 nM of serotonin (n=5, p=0.03). The effect of serotonin was similar to that of PDGF and VEGF, but weaker than that of FGF-2 at their optimal dose. Serotonin also significantly enhanced FGF-2, PDGF or VEGF -induced CFU-F formation (p<0.05). 5-HT 2A, 2B and 2C receptors were also demonstrated in bone marrow stromal cells by RT-PCR and around 1% positive confirmed by FACS. Results on thrombopoiesis showed that 5-HT2A, 2B and 2C receptors were expressed strongly (80–99%) on MB megakaryocytes and MK cell lines. Serotonin also increased the size of cultured megakaryocyte suggesting it has a promoting effect on megakaryocyte maturation. Ketanserin, a 5-HT2B receptor antagonist, was showed in the same study to block the mitogenic effect on megakaryocyte differentiation. Serotonin also has an effect on actin re-organization in Meg-01 cells. We have provided the evidence of serotonin as a growth factor for blood stem cells and MK cells. Based on this concept, alternative drug could be developed for the treatment of thrombocytopenia.
Frequency of Heparin-Platelet Factor 4 Antibodies among Patients with Acute Coronary Syndromes Presenting to the Emergency Department.
Authors: Francis John L. , Drexler Alane , Walker Jamie , Duncan Mary Kathryn , Ahmad Sarfraz 
Published: October 2019

Abstract
Heparin is widely used to treat patients that present with acute coronary syndromes (ACS). A significant, albeit under-recognized complication of heparin therapy is heparin-induced thrombocytopenia (HIT), which is estimated to occur in 1–3% of patients. A significantly higher proportion (20–50%) of patients undergoing cardiac surgery and other invasive cardiology procedures develop an antibody against the heparin-platelet factor 4 (HPF4) complex. Most patients remain asymptomatic, but are nevertheless at risk for HIT with subsequent heparin exposure. Patients with severe coronary artery disease frequently have multiple hospital admissions, and heparin exposures. HPF4 antibodies are transient, and most will become undetectable three months after their initial formation. Therefore, patients with a recent history of hospitalization would be at greater risk of HIT on heparin re-exposure. We tested this hypothesis in a prospective study of patients with ACS presenting to the Emergency Department. We studied 230 patients presenting to the ED with ACS. Patients were stratified into Group 1 (having a recent [<6 months] history of hospital admission), or Group 2 (having a more remote [or no] history). Plasma samples were tested for HPF4 antibodies with a commercially available ELISA and positive samples were re-tested with a serotonin release assay (SRA). Sixteen patients (7.0%) tested positive for HPF4 antibodies by ELISA. Group 1 subjects had a higher incidence of HPF4 antibodies (10.7%) than Group 2 patients (3.2%). Of the 16 patients positive by ELISA, 14 were also tested by SRA. Of these, 7 were positive, 6 were negative and 2 gave borderline results. We conclude that approximately 7% of all patients presenting with acute coronary syndromes have a pre-existing HPF4 antibody. The incidence of a positive test is tripled in patients that have been recently hospitalized with high probability of recent heparin exposure. A significant proportion of these patients has a functionally active HPF4 antibody, which would presumably carry a higher risk of clinical HIT if re-exposed to heparin therapy for ACS and subsequent cardiovascular procedures. Our data suggest that high-risk individuals can be identified on a history of recent hospital admissions, and should receive a non-heparin anticoagulant, e.g. a direct thrombin inhibitor, until their HPF4 antibody status can be established.
Inhibition of Phosphotyrosine Phosphatase-1B (PTP1B) Induces Resistance to the ABL Kinase Inhibitor Imatinib Mesylate (Gleevec®) in BCR-ABL Positive Leukemic Cells.
Authors: Koyama Noriko , Koschmieder Steffen , Tyagi Sandhya , Myloch Silke , Nuernberger Heike , Rossmanith Tanja , Hofmann Wolf Karsten , Hoelzer Dieter , Ottmann Oliver Gerhard 
Published: October 2019

Abstract
BCR-ABL chronic myeloid leukemia (CML) and acute lymphoblastic leukemia (ALL) have recently received much attention as model diseases for the effectiveness of targeted drug therapy. The ABL kinase inhibitor imatinib mesylate has revolutionized treatment of CML. However, a serious drawback to this specific treatment is the emergence of drug resistance. Protein tyrosine phosphatase-1B (PTP1B) has been demonstrated to block the BCR-ABL mediated transformation of hematopoietic cells in vitro and in vivo. Therefore the impact of PTP1B function on imatinib-response of the BCR-ABL positive cell line K562 and an imatinib-resistant subclone of the cell line SupB15 was investigated.
K562 cells were transfected with wild-type PTP1B (K562/PTP1B), a substrate-trapping dominant-negative mutant PTP1B (K562/D181A), or an empty vector (K562/mock), cultured in the presence or absence of imatinib (0.25–1.0 μM) and analyzed for proliferation, apoptosis and differentiation. K562/PTP1B and K562/D181A cells displayed 1.6-fold higher and 13-fold lower phosphatase activity than K562/mock cells, resp. In both K562/mock and K562/PTP1B cells, 0.5 μM imatinib induced growth arrest, an increase of cells in sub-G1 apoptotic phase (36.9±2.0% and 38.6±3.8%, resp.) and a decrease of cells in S/G2/M phases (18.9±1.1% and 23.7±2.7%, resp.) as determined by FACS analysis of propidium iodide stained cells. Imatinib-induced apoptosis was further confirmed by Annexin V staining and Western blot analysis showing increased active caspase-3 and -8 protein levels and induction of poly ADP-Ribose Polymerase (PARP) cleavage in both cells. Low doses of imatinib (0.25 μM) promoted erythroid differentiation of these cells as evaluated by enhanced expression of glycophorin A. Conversely, K562/D181A cells were significantly less sensitive to imatinib-induced growth arrest (sub-G1: 25±3.9 %, S/G2/M: 34.2±1.4 %) apoptosis, and promotion of erythroid differentiation. Inhibition of PTP1B phosphatase activity by the PTP1B inhibitor bis(N,N-Dimethylhydroxamido)hydroxooxovanadate (DHMV) decreased imatinib-induced apoptosis in wild-type K562 cells (46.7% vs. 28.3% annexin V positive cells; p<0,01). Moreover, the imatinib-resistant subclone of the ALL cell line SupB15, which had been generated in the presence of 1μM imatinib, showed significantly lower PTP1B activity (64.3±5.6%, p<0.05) as compared with imatinib-sensitive wild type cells. In conclusion, our data demonstrate that functional PTP1B is required for imatinib-induced apoptosis, growth arrest, and differentiation. Alterations of PTP1B gene expression and function might contribute to imatinib-resistence and should therefore be assessed in patients with BCR-ABL positive chronic and acute leukaemia who developed restance to imatinib.
Effects of Adaphostin, a Novel Tyrphostin Inhibitor, in Diverse Models of Imatinib Mesylate Resistance.
Authors: Chandra Joya , Tracy Jeannette , Gorre Mercedes , Talpaz Moshe , Griffin James , Verstovsek Srdan , Beran Miloslav , Sawyers Charles , Sausville Edward , Kaufmann Scott 
Published: October 2019

Abstract
The impetus for kinase inhibition as a therapeutic endpoint in leukemia research has been driven largely by the success of imatinib mesylate in chronic myelogenous leukemia. However, while imatinib mesylate has been extremely effective in the treatment of chronic phase CML, resistant disease often emerges in both Philadelphia positive ALL and aggressive phase CML patients. Adaphostin is a tyrphostin inhibitor originally developed to target the bcr/abl kinase and demonstrates selectivity in CML patient isolates. Here we show that in vitro, adaphostin is cytotoxic in numerous models that are resistant to imatinib. Features of adaphostin action in bcr/abl containing cells include apoptosis induction via an oxidant dependent mechanism and degradation of bcr/abl protein. Cell lines containing point mutations in p210 bcr/abl which confer imatinib resistance exhibit intracellular peroxide production and DNA fragmentation in response to adaphostin. Bcr/abl degradation also occurs but can be dissociated from peroxide production and subsequent apoptosis signaling. Similar data has also been obtained in cell lines containing p190 bcr/abl. Studies extending these observations into mononuclear and polymorphonuclear cells from imatinib resistant CML patients and Ph+ ALL patients confirm the same mechanism in primary clinical isolates. Collectively, these data suggest that reactive oxygen species generation by adaphostin bypasses imatinib resistance in CML and Ph+ ALL. Further studies dissecting the mechanism of ROS generation by adaphostin in imatinib resistant cells may lead to the identification of new therapeutic targets.
Efficient Gene Transfer into Primate ES Cells and Stable Transgene Expression during Hematopoietic Differentiation by Sendai Virus Vector.
Authors: Hanazono Yutaka , Sasaki Kyoko , Inoue Makoto , Shibata Hiroaki , Ueda Yasuji , Hasegawa Mamoru , Ozawa Keiya 
Published: October 2019

Abstract
Since human embryonic stem (ES) cell lines have the ability to both proliferate indefinitely and differentiate into multiple tissue cells, they are expected to have clinical applications as well as to serve as models for basic research and drug development. Although efficient and stable gene transfer into primate ES cells would be useful for such purposes, it has been difficult and only lentiviral vectors have been successful in achieving it. We have previously developed Sendai virus (SeV) vector that is capable of self-replication but incapable of transmitting to other cells. The vector replicates in the form of negative-sense single-stranded RNA in the cytoplasm of infected cells and does not go through a DNA phase. SeV vector can efficiently introduce foreign genes without toxicity into various types of cells including hematopoietic progenitor cells. In this study, we have examined the efficacy of SeV vector to introduce a new genetic material into nonhuman primate cynomolgus ES cells.
Cynomolgus ES cells were once exposed to a SeV vector carrying the GFP gene (50 TU/ml). About 60% of cells stably fluoresced at least for a month as assessed by flow cytometry. Fluorescent ES-cell colonies were plucked under a fluorescent microscope once at one month after infection and they were propagated. The GFP gene was then vigorously and stably expressed in about 90% of the cells for a year. The undifferentiated cell fractions were unchanged after the SeV infection of ES cells as assessed by staining with alkaline phosphatase and SSEA-4. In addition, the infected, fluorescent ES cells were able to form fluorescent teratomas when transplanted into immunodeficient mice. Thus, the SeV infection did not hamper pluripotency of ES cells and transgene silencing did not occur during the teratoma formation in vivo. For induction of hematopoietic differentiation, the infected, fluorescent ES cells were seeded onto OP9 stromal cells in the presence of multiple cytokines including BMP-4 and VEGF. Cells at day 18 were subjected to clonogenic hematopoietic colony formation assays. Resulting colonies at day 14 fluoresced and the colonies contained NBT-positive, fluorescent mature granulocytes. Thus, SeV-mediated transgene was stably expressed even after the terminal differentiation to granulocytes. In addition, SeV-mediated GFP expression levels in ES cells could be reduced dose-dependently by the addition of an anti-RNA virus drug, ribavirin, to the culture. Upon discontinuation of ribavirin treatment, the cells regained the original level of GFP expression. Ribavirin is an inhibitor of viral RNA polymerase and used for treatment of hepatitis C infection. In conclusion, SeV vector will be a useful tool for gene transfer into primate ES cells and the method of using anti-viral drugs should allow further investigation for regulated SeV-mediated gene expression.
Prospects for Dendritic Cell Vaccination Against Fungal Infections in Hematopoietic Transplantation.
Authors: Perruccio Katia , Bozza Silvia , Montagnoli Claudia , Bellocchio Silvia , Aversa Franco , Martelli Massimo F. , Bistoni Francesco , Velardi Andrea , Romani Luigina 
Published: October 2019

Abstract
Dendritic cells (DCs) are uniquely able to initiate and control the immune response to fungi. DCs function at three levels in the manipulation of the immune response to these pathogens: 1) they mount an immediate or innate response to them, for example by producing inflammatory mediators upon capture and phagocytosis; 2) through these preceding innate functions, they decode the fungus-associated information and translate it in qualitatively different Th responses; 3) and they are key in containing and dampening inflammatory responses by tolerization through the induction of regulatory T cells (Treg). We demonstrated that both murine and human DCs sense fungi in a morphotype-specific manner, through the engagement of distinct recognition receptors ultimately affecting cytokine production and costimulation (Romani et al. Int Immunol. 2003). In this study we analyzed both myeloid and plasmacytoid murine and human DCs and we observed that they phagocytose fungi and undergo functional maturation in response to them. However, their activation program for cytokine production was different, being IL-12 mainly produced by myeloid DCs and IL-12, IL-10 and IFN-gamma mainly produced by plasmacytoid DCs. This resulted in a distinct ability for T-cell priming, being Th1, Th2 and Treg differently activated by the different DC subsets. The ability of fungus-pulsed DCs to prime for Th1, and Th2 cell activation upon adoptive transfer in vivo correlated with the occurrence of resistance and susceptibility to the infections, respectively. Antifungal protective immunity was also induced upon adoptive transfer of DCs transfected with fungal RNA (Bacci et al. J Immunol. 2002; Bozza et al. Blood. 2003). The efficacy was restricted to DCs transfected with RNA from yeasts or conidia but not with RNA from fungal hyphae. The effect was fungus-specific, as no cross-protection was observed upon adoptive transfer of DCs pulsed with either fungal species. The infusion of fungus-pulsed or RNA-transfected DCs accelerated the recovery of functional antifungal Th1 responses in mice with allogeneic hematopoietic stem cell transplantation (HSCT) without triggering graft-versus-host disease (GvHD) and affected the outcome of the infections. As the ability to respond to fungi was defective in peripheral DCs from patients with HSCT in terms of phagocytosis, cytokine production, and donor T-cell priming, our findings suggest that the adoptive transfer of DCs may restore immunocompetence in HSCT by contributing to the educational program of T-cells. Thus, the remarkable functional plasticity of DCs in response to fungi can be exploited for the deliberate targeting of cells and pathways of cell-mediated immunity in response to fungal vaccines.
Fludarabine (Flu) Based Cytoreductive Regimen and T-Cell Depleted Grafts from Unrelated or Mismatched Related Donors for the Treatment of High Risk Patients with Fanconi Anemia (FA).
Authors: Boulad Farid , Auerbach Arleen D. , Kernan Nancy A. , Small Trudy N. , Prockop Susan E. , Chaudhury Sonali , Castanza Joanne , Casson Anne , Copeland Catherine , Abendroth Heidi , Collins Nancy , O’Reilly Richard J. 
Published: October 2019

Abstract
Between 05/98 and 06/04, 15 consecutive patients with FA received hematopoietic stem cell transplants (SCT) from alternative donors at our Center. There were 7 males and 8 females aged 5 to 24 years (median 11.5). Hematologic diagnoses included aplastic anemia (AA) (N=5), myelodysplastic syndrome (MDS) in RAEB (N=4), RAEBT (N=1) or acute myelogenous leukemia (AML) (N=5). High risk features included: Age > 20 years (n=4), prior multiple transfusions (n=11), prior androgen treatment (n=12), prior infections (n=10), or advanced MDS or AML (n=9). Eight pts had related mismatched donors transplants with respective matching at 3/6 (6/10), 4/6 (6/10), 4/6 (7/10) (n=2)), 5/6 (8/10) (n=3) and 5/6 (9/10) HLA-antigens. Seven pts had unrelated donors transplants with respective matching at 5/6 (7/10), 5/6 (8/10) (n=2), 5/6 (9/10) and 6/6 (10/10) (n=3) HLA-antigens. Cytoreduction included single dose total body irradiation (SDTBI) (450 cGy), fludarabine (Flu) (30 mg/m2 x 5) and cyclophosphamide (Cy) (10 mg/Kg x 4). Immunosuppression included rabbit anti-thymocyte globulin (Thymoglobulin) and tacrolimus for all patients. Grafts were G-CSF mobilized CD34+ and E-rosette negative (E-) peripheral blood stem cell transplants for 12 pts and soybean agglutinin negative (SBA-) and E-rosette negative marrow transplants for 3 pts. Cell doses of the grafts were 1.5 – 29.6 x 106 CD34 cells/Kg and 0 – 26 x 103 CD3 cells/Kg. As evidenced by RFLP or FISH, all 15 evaluable pts were fully engrafted and complete chimeras. Fourteen pts were evaluable for graft-versus-host disease (GvHD). GvHD of the skin and of the gut was suspected in two pts but resolved completely prior to immunosuppressive treatment. With a median follow-up of 2.5 years (range 0.2–6), 13 of 15 pts are alive and 11 of 15 are alive disease-free. There were two deaths: one pt died from sepsis/ARDS at 2 months post SCT and one pt from pneumonitis/ARDS and EBV-infection 6 months post SCT. Three pts relapsed (MDS-RAEB x 1 – AML x 2): One pt relapsed 7 months post transplant, received a 2nd transplant from the same donor following busulfan and Flu and is alive, disease-free 18 months post SCT, while the other two pts are awaiting a second SCT. In summary, this cytoreductive regimen used with T-cell depleted stem cell transplants from unrelated or HLA-mismatched related donors for the treatment of high risk patients with Fanconi anemia, results in rapid hematopoietic engraftment and lymphohematopoietic reconstitution with minimal GVHD and a high disease-free survival.