bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thrombin Generation by Apoptotic Vascular Smooth Muscle Cells
Authors: Flynn Paul D. , Byrne Christopher D. , Baglin Trevor P. , Weissberg Peter L. , Bennett Martin R. 
Published: October 2019

AbstractThrombin activation requires assembly of a prothrombinase complex of activated coagulation factors on an anionic phospholipid surface, classically provided by activated platelets. We have previously shown that anionic phosphatidylserine is exposed by rat vascular smooth muscle cells (VSMCs) undergoing apoptosis after serum withdrawal. In this study, using a chromogenic assay, we have shown thrombin generation by apoptotic VSMCs expressing c-myc (VSMC-myc) with an area under the thrombin-generation curve (AUC) of 305 ± 17 nmol⋅min/L and a peak thrombin (PT) of 154 ± 9 nmol/L. The thrombin-generating potential of the apoptotic VSMC-myc cells was greater than that of unactivated platelets (P = .003 for AUC; P = .0002 for PT) and similar to calcium-ionophore activated platelets (AUC of 332 ± 15 nmol⋅min/L, P = .3; PT of 172 ± 8 nmol/L, P = .2). Thrombin activation was also seen with apoptotic human VSMCs (AUC of 211 ± 8 nmol⋅min/L; PT of 103 ± 4 nmol/L) and was inhibited by annexin V (P < .0001 for AUC and PT). VSMC-myc cells maintained in serum generated less thrombin than after serum withdrawal (P = .0002 for AUC and PT). VSMCs derived from human coronary atherosclerotic plaques that apoptose even in serum also generated thrombin (AUC of 260 ± 2 nmol⋅min/L; PT of 128 ± 4 nmol/L). We conclude that apoptotic VSMCs possess a significant thrombin-generating capacity secondary to phosphatidylserine exposure. Apoptotic cells within atherosclerotic plaques may allow local thrombin activation, thereby contributing to disease progression.
Frequency of Immune Thrombocytopenia in Newborns: A Prospective Study
Authors: Dreyfus Marie , Kaplan Cécile , Verdy Elizabeth , Schlegel Nicole , Durand-Zaleski Isabelle , Tchernia Gil ,   the Immune Thrombocytopenia Working Group
Published: October 2019

Abstract
Thrombocytopenia is a common condition in distressed newborns, but little is known about thrombocytopenia in an unselected cohort of neonates. In an attempt to address this issue, a multicenter prospective study was conducted in three obstetrical wards of AP-HP in Paris. We found the frequency of neonatal thrombocytopenia (<150 × 109/L) to approximate 0.9% (48 of 5,632 appropriate samples). An immune mechanism was likely to be the cause of thrombocytopenia in 10 of the 33 cases studied, implying an incidence of 0.3% of immune neonatal thrombocytopenia in the general population. The frequency of alloimmune thrombocytopenia was 1.5/1,000 liveborn neonates, and 1/1,000 when considering anti–HPA-1a allo-immunization. Because thrombocytopenia, whatever its cause, was often silent and delayed, it appears that the only way to detect neonatal thrombocytopenia in time to prevent its potential disastrous complications would be to perform a systematic neonatal blood sampling for platelet count. All cases of ascertained thrombocytopenia should then be screened for an immune mechanism to enable early detection of autoimmune diseases in mothers and careful monitoring of subsequent pregnancies and deliveries, leading to appropriate prevention of potential severe deleterious effects in the offspring.
Tumor Dormancy and Cell Signaling. V. Regrowth of the BCL1 Tumor After Dormancy Is Established
Authors: Vitetta Ellen S. , Tucker Thomas F. , Racila Emilian , Huang Yi-Wu , Marches Radu , Lane Nancy , Scheuermann Richard H. , Street Nancy E. , Watanabe Takeshi , Uhr Jonathan W. 
Published: October 2019

AbstractThe majority of BALB/c mice immunized with the BCL1 lymphoma-derived idiotype (Id+) IgM and subsequently challenged with BCL1 tumor cells develop a state of tumor dormancy. The vast majority of dormant lymphoma cells are in cell cycle arrest, but there are also residual replicating cells. In the present studies, we attempted to define features of both the dormant lymphoma cells and the host that lead to escape from dormancy. Escape from dormancy occurs at a steady rate over a 2-year period, suggesting that it is a stochastic process. We found that, in the majority of mice, escape was due to the emergence of genetic variants that were no longer susceptible to the anti-Id–mediated induction of dormancy. Ten percent of these variants were Id−; the remainder were Id+ but could grow in the presence of anti-Id antibodies, suggesting that there were mutations in molecules involved in one or more mIg-mediated negative-signaling pathways. In two of five such escapees, alterations in either Syk, HS1, and/or Lyn were observed. In a small percentage of mice, a low titer of circulating anti-Id antibody before tumor challenge correlated with a subsequent, more rapid loss of dormancy.
Distribution of ABL and BCR Genes in Cell Nuclei of Normal and Irradiated Lymphocytes
Authors: Kozubek S. , Lukášová E. , Rýznar L. , Kozubek M. , Lišková A. , Govorun R.D. , Krasavin E.A. , Horneck G. 
Published: October 2019

AbstractUsing dual-color fluorescence in situ hybridization (FISH) combined with two-dimensional (2D) image analysis, the locations of ABL and BCR genes in cell nuclei were studied. The center of nucleus-to-gene and mutual distances of ABL and BCR genes in interphase nuclei of nonstimulated and stimulated lymphocytes as well as in lymphocytes stimulated after irradiation were determined. We found that, after stimulation, the ABL and BCR genes move towards the membrane, their mutual distances increase, and the shortest distance between heterologous ABL and BCR genes increases. The distribution of the shortest distances between ABL and BCR genes in the G0 phase of lymphocytes corresponds to the theoretical distribution calculated by the Monte-Carlo simulation. Interestingly, the shortest ABL-BCR distances in G1 and S(G2 ) nuclei are greater in experiment as compared with theory. This result suggests the existence of a certain regularity in the gene arrangement in the G1 and S(G2 ) nuclei that keeps ABL and BCR genes at longer than random distances. On the other hand, in about 2% to 8% of lymphocytes, the ABL and BCR genes are very close to each other (the distance is less than ∼0.2 to 0.3 μm). For comparison, we studied another pair of genes, c-MYC and IgH, that are critical for the induction of t(8; 14) translocation that occurs in the Burkitt's lymphoma. We found that in about 8% of lymphocytes, c-MYC and IgH are very close to each other. Similar results were obtained for human fibroblasts. γ-Radiation leads to substantial changes in the chromatin structure of stimulated lymphocytes: ABL and BCR genes are shifted to the nuclear center, and mutual ABL-BCR distances become much shorter in the G1 and S(G2 ) nuclei. Therefore, we hypothesize that the changes of chromatin structure in the irradiated lymphocytes might increase the probability of a translocation during G1 and S(G2 ) stages of the cell cycle. The fact that the genes involved in the t(8; 14) translocation are also located close together in a certain fraction of cells substantiates the hypothesis that physical distance plays an important role in the processes leading to the translocations that are responsible for oncogenic transformation of cells.
Cyanocobalamin [c-lactam] Inhibits Vitamin B12 and Causes Cytotoxicity in HL60 Cells: Methionine Protects Cells Completely
Authors: Matthews J.H. 
Published: October 2019

AbstractThe [c-lactam] derivative of cobalamin antagonizes vitamin B12 in vivo. Therefore, we investigated its effects in tissue culture to develop a model in which to study vitamin B12-deficient hemopoiesis. HL60 cells were cultured in medium containing either methionine or L-homocysteine thiolactone, and various concentrations of 5-methyltetrahydrofolate or pteroylglutamic acid. In medium with L-homocysteine thiolactone, 5-methyltetrahydrofolate, and dialyzed serum, cyanocobalamin [c-lactam] caused cell death, reversible by additional vitamin B12 . Pteroylglutamic acid did not prevent this cytotoxic effect. Methionine completely protected cells against cyanocobalamin [c-lactam] for periods of up to 4 months of culture, irrespective of the folate source. Cyanocobalamin [c-lactam] reversibly impaired the incorporation of 5-[14CH3]-tetrahydrofolate and [1-14C] propionic acid by intact cells, consistent with inhibition of methionine synthase and methylmalonyl-CoA mutase. A substantial proportion of 5-[14CH3]-tetrahydrofolate uptake could not be suppressed by methionine and may, therefore, have occurred outside of the methionine synthase pathway. These findings are the first indication that cyanocobalamin [c-lactam] antagonizes vitamin B12 in vitro and causes cell death from methionine deficiency. The model should be valuable for investigating the biochemical pathology of vitamin B12-deficient hemopoiesis. The results suggest that methylfolate is not trapped when methionine synthase is inhibited in HL60 cells, but they do not disprove the methylfolate trap hypothesis as applied to normal blood cells.
Organization of the Human LU Gene and Molecular Basis of the Lua/Lub Blood Group Polymorphism
Authors: El Nemer Wassim , Rahuel Cecile , Colin Yves , Gane Pierre , Cartron Jean Pierre , Le Van Kim Caroline 
Published: October 2019

AbstractThe Lutheran (Lu) blood group antigens and the B-cell adhesion molecule (B-CAM) epithelial cancer antigen are carried by recently cloned integral glycoproteins that belong to the Ig superfamily. We have previously shown that the Lu and B-CAM antigens are encoded by the same gene, LU, and that alternative splicing of the primary transcript most likely accounts for the presence of both antigens on two isoforms that differ by the length of their cytoplasmic tails. In the present report, we isolated the human LU gene by cloning a 20-kb HindIII fragment from Lu(a − b+) genomic DNA. The LU gene is organized into 15 exons distributed over 12.5 kb. Alternative splicing of intron 13 generates the 2.5- and 4.0-kb transcript spliceoforms encoding the long tail and the short tail Lu polypeptides, respectively. Sequencing of the major mRNA species (2.5 kb) amplified from human bone marrow, kidney, placenta, and skeletal muscle did not suggest the presence of tissue-specific Lu glycoprotein isoforms. The same transcription initiation point, located 22 bp upstream from the initiation codon, was characterized in several tissues. In agreement with the wide tissue distribution of the Lu messengers, the GC-rich proximal 5′ flanking region of the LU gene does not contain TATA or CAAT boxes, but includes several potential binding sites for the ubiquitous Sp1 transcription factor. In addition, the distal 5′ region, encompassing nucleotides −673 to −764, contains clustered binding sequences for the GATA, CACCC, and Ets transcription factors. Analysis of the coding sequences amplified from genomic DNA of Lu(a + b−) or Lu(a − b+) donors showed a single nucleotide change in exon 3 (A229G) that correlates with an Aci I restriction site polymorphism and results in a His77Arg amino-acid substitution. Polymerase chain reaction/restriction fragment length polymorphism analysis indicated that the A229G mutation is associated with the Lua/Lub blood group polymorphism. When expressed in Chinese hamster ovary (CHO) cells, Lu cDNAs carrying the A229 or the G229 produced cell surface proteins that reacted with anti-Lua or anti-Lub antibodies, respectively, showing that these nucleotides specify the Lua and Lub alleles of the Lutheran blood group locus. CHO cells expressing recombinant short-tail or long-tail Lu glycoproteins reacted as well with anti-Lu as with anti–B-CAM antibodies, providing the definitive proof that the Lu blood group and B-CAM antigens are carried by the same molecules.
Upregulation of Cortactin Expression During the Maturation of Megakaryocytes
Authors: Zhan Xi , Haudenschild Christian C. , Ni Yangson , Smith Elizabeth , Huang Cai 
Published: October 2019

AbstractCortactin is a potent filamentous actin-binding protein acting as a prominent substrate of Src tyrosine kinases. We have evaluated cortactin expression in a series of murine tissues and shown an abundant expression of cortactin in megakaryocytes and platelets. Cortactin, but not its related protein HS1, is upregulated during the phorbol 12-myristate 13-acetate (PMA)-mediated maturation of a human megakaryoblastic cell line CMK. Although the expression of Src-related kinases is also upregulated more rapidly than cortactin in PMA-treated CMK cells, tyrosine phosphorylation of cortactin appears to be only transiently elevated 4 days after PMA stimulation. In addition, cortactin expression is induced by thrombopoietin and interleukin-3 in megakaryocytes derived from murine bone marrow cells. Thus, cortactin represents a megakaryocyte-specific gene in bone marrow and the interaction of Src kinases with cortactin may be involved in the maturation of megakaryocytes.
Antithrombotic Efficacy in the Guinea Pig of a Derivative of Human Protein C With Enhanced Activation by Thrombin
Authors: Kurz Ken D. , Smith Tommy , Wilson Alexander , Gerlitz Bruce , Richardson Mark A. , Grinnell Brian W. 
Published: October 2019

AbstractConversion by α-thrombin of the zymogen human protein C (HPC) to activated protein C (aPC) is an important physiologic feedback control mechanism for the coagulation cascade. Although activation of HPC by thrombomodulin-bound thrombin is relatively rapid, activation by free thrombin occurs at a significantly slower rate. Previously, we generated a “hyper-activatable” derivative of HPC (FLIN-Q3) with an increased activation rate by free α-thrombin in vitro. In this study, the antithrombotic efficacy of FLIN-Q3 was compared with both native zymogen and aPC in an arteriovenous shunt model of thrombosis in the guinea pig. Recombinant proteins were infused 15 minutes before and throughout a 15-minute period while blood was circulated from carotid to jugular through tubing that enclosed a thread on which fibrin was deposited. Parallel dose-dependent antithrombotic responses were observed. Under these non–steady-state conditions, the calculated infusion doses associated with a 50% reduction of thrombus mass were 2.7, 24, and 250 mg/kg/h for aPC, FLIN-Q3, and HPC, respectively. Thrombus weight correlated inversely with plasma concentration of aPC, measured amidolytically, from either direct infusion of aPC or that generated from the zymogens in the animal, and similarly correlated inversely with anticoagulant activity measured by whole blood aPTT. Neither zymogen form showed significant aPC activity before shunt circulation, suggesting a requirement for exposure to thrombin. After the infusion was discontinued for 15 minutes, a second period of thrombus formation in the shunt demonstrated the ability of zymogen forms of PC, unlike aPC, to provide “on-demand” anticoagulant responses to repeated thrombotic stimuli. Thus, a “hyper-activatable” PC molecule such as FLIN-Q3 may represent a superior form of anticoagulant therapy than either the native zymogen or aPC.
A Cysteine Protease Inhibitor Prevents Activation-Induced T-Cell Apoptosis and Death of Peripheral Blood Cells From Human Immunodeficiency Virus-Infected Individuals by Inhibiting Upregulation of Fas Ligand
Authors: Yang Yili , Liu Zhi-Hong , Ware Carl F. , Ashwell Jonathan D. 
Published: October 2019

AbstractActivation of T-cell hybridomas, preactivated normal T cells, and peripheral blood lymphocytes (PBL) from human immunodeficiency virus (HIV)-infected individuals results in apoptosis. In the first two cases, apoptosis is caused by the upregulation of Fas ligand (FasL) and its subsequent interaction with Fas; the mechanism for the spontaneous and activation-induced death of lymph node cells and PBL from HIV+ blood is not known. A number of protease inhibitors have been shown to prevent T-cell apoptosis under all of these circumstances, but the mechanism of action has not been determined. Here we show that the cysteine protease inhibitor E64d prevents activation-induced T hybridoma cell death by inhibiting the upregulation of FasL. Quantitative polymerase chain reaction (PCR) demonstrated that mRNA for FasL is expressed at low levels in fresh PBL from HIV-infected blood, but increases in cultured PBL from both uninfected and HIV-infected donors. The ex vivo apoptosis of PBL from HIV+ donors was prevented by adding the soluble extracellular domain of Fas, demonstrating a requisite role for Fas/FasL interactions in this form of cell death. Furthermore, while having no effect on the death of PBL from HIV-infected blood stimulated directly via Fas, E64d inhibited FasL upregulation. Thus, aberrant apoptosis of cultured PBL from HIV-infected individuals is mediated by FasL and Fas, and E64d blocks this apoptosis by inhibiting the upregulation of FasL. These results are consistent with the hypothesis that the abnormal expression of Fas and the inducible expression of FasL contributes to the immunodeficiency of patients with acquired immune deficiency syndrome and suggest that modulation of FasL expression could be an effective target for therapeutic intervention.
The Role of Hyperuricemia in the Increased Cytokine Production After Lipopolysaccharide Challenge in Neutropenic Mice
Authors: Netea Mihai G. , Kullberg Bart Jan , Blok Willem L. , Netea Romana T. , W.M. Van der Meer Jos 
Published: October 2019

AbstractPatients with severe granulocytopenia are more susceptible to severe infections and sepsis. Proinflammatory cytokines such as tumor necrosis factor-α (TNF ), interleukin-1α (IL-1α), and IL-1β play an important role in the pathophysiology of sepsis. The profile of these proinflammatory cytokines after lipopolysccharide (LPS) challenge in cyclophosphamide-induced neutropenic mice was assessed, and possible mechanisms responsible for the modified cytokine production were studied. After LPS, both circulating concentrations of TNF and IL-1α in neutropenic mice were 50% to 200% higher than those of controls, whereas IL-1β concentrations were not modified. The kinetics of cytokine production were similar in neutropenic and control animals. The susceptibility of neutropenic mice to an LPS challenge was increased. The observed overproduction of TNF and IL-1α was not due to a direct effect of cyclophosphamide treatment. Because circulating concentrations of uric acid were increased in the neutropenic mice, the effect of hypouricemic treatment with allopurinol and sodium bicarbonate was investigated; such treatment in neutropenic mice challenged with LPS was followed by an improved survival and a reduced proinflammatory cytokine production towards the concentrations in control mice. Hyperuricemia induced by repeated administrations of uric acid in normal mice led to an increased TNF production after LPS. In conclusion, neutropenic mice respond with enhanced cytokine production and increased susceptibility to an LPS challenge, and hyperuricemia probably plays an important role in this phenomenon.
Frequent Jumping Translocations of Chromosomal Segments Involving the ABL Oncogene Alone or in Combination With CD3-MLL Genes in Secondary Leukemias
Authors: Tanaka Kimio , Arif Mansyur , Eguchi Mariko , Kyo Taiichi , Dohy Hiroo , Kamada Nanao 
Published: October 2019

Abstract
Seven secondary leukemia patients were treated for solid tumors or malignant lymphoma with anticancer drugs or radiation. We studied bone marrow samples from these patients by fluorescence in situ hybridization (FISH). Of the seven patients, three had increased signals for the ABL oncogene (9q34) on interphase nuclei and at metaphase. One of the three patients also had four signals for the CD3 (MLL) region (11q23). Whole painting probes revealed that these chromosomal regions were translocated onto structurally abnormal chromosomes, resulting in partial tri-, tetra- or penta-somy of these regions. We called this type of translocation “segmental jumping translocation (SJT).” SJT of the ABL oncogene was not detected in samples from 15 patients with de novo acute myelocytic leukemia (AML), 12 with myelodysplastic syndrome (MDS), or 20 with chronic myelocytic leukemia (CML) at the chronic phase. Furthermore, monosomy 7 was also found in the patients with the gene amplification. These results indicate that SJT of ABL and/or CD3 (MLL) genes is associated with the leukemogenesis of secondary leukemia. The SJT may be one mechanism of gene amplification.
Altered Erythrocytes and a Leaky Block in B-Cell Development in CD24/HSA-Deficient Mice
Authors: Nielsen P.J. , Lorenz B. , Müller A.M. , Wenger R.H. , Brombacher F. , Simon M. , von der Weid T. , Langhorne J. , Mossmann H. , Köhler G. 
Published: October 2019

AbstractThe heat stable antigen (HSA, or murine CD24) is a glycosyl phosphatidylinositol-linked surface glycoprotein expressed on immature cells of most, if not all, major hematopoietic lineages, as well as in developing neural and epithelial cells. It has been widely used to stage the maturation of B and T lymphocytes because it is strongly induced and then repressed again during their maturation. Terminally differentiated lymphocytes, as well as most myeloid lineages, are negative for HSA. Erythrocytes are an exception in that they maintain high levels of HSA expression. HSA on naive B cells has been shown to mediate cell-cell adhesion, while HSA on antigen-presenting cells has been shown to mediate a costimulatory signal important for activating T lymphocytes during an immune response. Here, we characterize mice that lack a functional HSA gene, constructed by homologous recombination in embryonic stem cells. While T-cell and myeloid development appears normal, these mice show a leaky block in B-cell development with a reduction in late pre-B and immature B-cell populations in the bone marrow. Nevertheless, peripheral B-cell numbers are normal and no impairment of immune function could be detected in these mice in a variety of immunization and infection models. We also observed that erythrocytes are altered in HSA-deficient mice. They show a higher tendency to aggregate and are more susceptible to hypotonic lysis in vitro. In vivo, the mean half-life of HSA-deficient erythrocytes was reduced. When infected with the malarial parasite Plasmodium chabaudi chabaudi, the levels of parasite-bearing erythrocytes in HSA-deficient mice were also significantly elevated, but the mice were able to clear the infection with kinetics similar to wild-type mice and were immune to a second challenge. Thus, apart from alterations in erythrocytes and a mild block in B-cell development, the regulated expression of HSA appears to be dispensable for the maturation and functioning of those cell lineages that normally express it.