bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of thrombopoietin on the development of megakaryocytes and platelets: an ultrastructural analysis
Authors: Zucker-Franklin D , Kaushansky K 
Published: October 2019

Abstract
Megakaryocytopoiesis and platelet production can be assessed with reasonable accuracy by quantitative and functional analyses of circulating platelets. The evaluation of megakaryocytopoiesis in culture has remained unsatisfactory, particularly because platelet production is rarely observed. In mouse culture systems, megakaryocytes have been identified almost entirely by measurements of acetyl cholinesterase, size, and ploidy without concomitant assessment of maturation based on such criteria as the formation of granules, demarcation membranes, and cytoplasmic fragmentation. The availability of various thrombopoietic cytokines, in particular thrombopoietin (TPO), and their imminent clinical use has made a more detailed understanding of their effect on differentiation and maturation of the MK lineage more urgent. Therefore, ultrastructural analyses were performed on megakaryocyte-depleted serum-free mouse bone marrow cultures in the presence of TPO alone, TPO plus other cytokines, or under conditions in which TPO and/or other cytokines were blocked with neutralizing agents. These studies show that, while cytokines that use the gp130 receptor subunit may function synergistically with TPO, in the absence of TPO, such cultures do not yield morphologically recognizable MK. On the other hand, TPO alone is able to drive MK to full maturation as evidenced by the generation of granules, demarcation membranes, and cytoplasmic fragmentation into platelets.
In Vivo Efficacy and Toxicity of a Single-Chain Immunotoxin Targeted to CD40
Authors: Francisco Joseph A. , Schreiber George J. , Comereski Chuck R. , Mezza Laurence E. , Warner Garvin L. , Davidson Thomas J. , Ledbetter Jeffrey A. , Siegall Clay B. 
Published: October 2019

AbstractG28-5 sFv-PE40 is a single-chain immunotoxin targeted to CD40, which is highly expressed on human hematologic malignancies, including non-Hodgkin's lymphoma, B-lineage leukemias, multiple myeloma, and Hodgkin's disease, as well as certain carcinomas. In vitro analysis showed that this monovalent immunotoxin had a binding affinity of 3 nmol/L, within 15-fold of the bivalent parental monoclonal antibody. G28-5 sFv-PE40 was stable when incubated in mouse serum at 37°C for 6 hours and cleared from the circulation of mice with a half-life of 16.7 minutes. This immunotoxin was effective in treating human Burkitt's lymphoma xenografted SCID mice with complete responses, defined by an asymptomatic phenotype for greater than 120 days, obtained at doses of 0.13 to 0.26 mg/kg. The efficacy of treatment was dependent on the schedule used, with every three days for five injections being the most effective tested. The toxicity of G28-5 sFv-PE40 was examined in SCID mice, rats, and monkeys, with the maximum tolerated dose being 0.48, 1.0, and 1.67 mg/kg, respectively. Comparative immunohistology showed that the G28-5 specificity was qualitatively similar between human and monkey tissue. In summary, G28-5 sFv-PE40 was effective at inducing complete antitumor responses in lymphoma xenografted mice at doses that were well tolerated in mice, rats, and monkeys.
The HRX Proto-oncogene Product Is Widely Expressed in Human Tissues and Localizes to Nuclear Structures
Authors: Butler Lisa H. , Slany Robert , Cui Xiangmin , Cleary Michael L. , Mason David Y. 
Published: October 2019

AbstractChromosomal rearrangement of the HRX (MLL, ALL-1, Htrx) gene situated at chromosome band 11q23 is one of the most frequent genetic changes in infant leukemias of myeloid and lymphoid lineage and in treatment-induced secondary leukemias. The HRX gene codes for a predicted 431-kD protein that shows significant homology to the Drosophila trithorax protein, an Hox epigenetic regulator. Typically, the region encoding the HRX gene is rearranged, mostly in reciprocal translocations with a number of partners, resulting in a range of fusion genes. However, this is not the only abnormality affecting HRX because partial duplication of the gene, as well as interstitial deletions, can occur. Despite extensive studies of HRX at the genetic level, the protein products of the HRX gene and their patterns of expression in normal and leukemic cells remain uncharacterized. In this study we analyzed the distribution and localization of HRX proteins in cell lines and human tissues, using both polyclonal and monoclonal antibodies. The specificity of these reagents was confirmed using cells transfected with the HRX-ENL fusion gene. Western blot analyses of protein extracts from cells carrying the t(11; 19) and t(4; 11) translocations showed HRX chimeric proteins whose migrations corresponded to the sizes predicted from analyses of translocation-induced fusion mRNAs expressed by the derivative 11 chromosomes. Immunocytochemical analysis showed a punctate distribution of wild-type and chimeric HRX proteins within cell nuclei, suggesting that HRX localizes to nuclear structures in cells with and without 11q23 translocations. Nuclear staining was found in the majority of tissues studied with the strongest reactivity in cerebral cortex, kidney, thyroid, and lymphoid tissues. Thus, HRX is widely expressed in most cell types including hematopoietic cells, a finding that precludes an immunocytochemical approach for diagnosis of leukemias bearing 11q23 structural abnormalities.
Hepatic Lesions of Chronic Disseminated Candidiasis May Become Invisible During Neutropenia
Authors: Pestalozzi Bernhard C. , Krestin Gabriel P. , Schanz Urs , Jacky Emanuel , Gmür Jürg 
Published: October 2019

Abstract
We describe the phenomenon of waning of focal hepatic and/or splenic lesions on abdominal computed tomographic (CT) scan during neutropenia in patients with chronic disseminated candidiasis. After observation of the phenomenon in one patient, a total of five cases were prospectively monitored with serial CT scans. After the diagnosis of disseminated candidiasis, hepatic lesions decreased in size and conspicuousness in three patients, while in two others they disappeared completely during a subsequent chemotherapy-induced neutropenia. After recovery of the neutrophils, the lesions reappeared or increased in conspicuousness in all five patients. Of three patients treated with a second cycle of myeloablative chemotherapy, lesions again decreased in two patients during neutropenia and increased again in one patient after neutrophil recovery. In all five patients, candidiasis eventually resolved after prolonged antifungal treatment. In chronic disseminated candidiasis, hepatic or splenic lesions may transiently disappear during neutropenia. Thus, antifungal therapy should not be discontinued on the basis of radiologic findings alone.
Prevalence and Natural History of Hepatitis C Infection in Patients Cured of Childhood Leukemia
Authors: Locasciulli Anna , Testa Marina , Pontisso Patrizia , Benvegnù Luisa , Fraschini Donatella , Corbetta Adele , Noventa Franco , Masera Giuseppe , Alberti Alfredo 
Published: October 2019

Abstract
The aim of this study was to ascertain prevalence and natural history of hepatitis C virus (HCV) infection in a large cohort of patients cured of childhood leukemia who had been followed prospectively for liver disease for at least 10 years since chemotherapy withdrawal: 114 consecutive patients entered the study. Liver function tests and ultrasonography were used to assess presence of liver disease. Patients were tested for antibody to HCV and for serum HCV-RNA at the end of chemotherapy and at the end of follow-up. At chemotherapy withdrawal, 56 patients (49%) were HCV-RNA positive, often without detectable anti-HCV, and in these cases, transaminase levels were more elevated during (P = .08) and after (P = .04) chemotherapy compared with HCV-RNA negative cases. Patients were then followed-up 13 to 27 years (mean, 17) after chemotherapy withdrawal. During this period, 38 initially anti-HCV negative patients seroconverted to anti-HCV and 17 initially anti-HCV positive cases lost reactivity. Forty patients were persistently HCV-RNA positive in serum, while 16 initially viremic patients became HCV-RNA negative during follow-up. At the end of the observation period, a persistent transaminase elevation was detected only in four HCV-RNA positive and anti-HCV positive cases, while no patient developed signs or symptoms of decompensated liver disease. Thus, hepatitis C was a frequent finding in long-term survivors after chemotherapy. It was associated with an atypical serologic profile and did not cause severe liver impairment over a period of 13 to 27 years.
Distinct Apoptotic Responses Imparted by c-myc and max
Authors: Nesbit Chadd E. , Fan Saijun , Zhang Hong , Prochownik Edward V. 
Published: October 2019

The c-myc oncoprotein accelerates programmed cell death (apoptosis) after growth factor deprivation or pharmacological insult in many cell lines. We have shown that max, the obligate c-myc heterodimeric partner protein, also promotes apoptosis after serum withdrawal in NIH3T3 fibroblasts or cytokine deprivation in interleukin-3 (IL-3)-dependent 32D murine myeloid cells. We now show that c-myc– and max-overexpressing 32D cells differ in the nature of their apoptotic responses after IL-3 removal or treatment with chemotherapeutic compounds. In the presence of IL-3, c-myc overexpression enhances the sensitivity of 32D cells to Etoposide (Sigma, St Louis, MO), Adriamycin (Pharmacia, Columbus, OH), and Camptothecin (Sigma), whereas max overexpression increases sensitivity only to Camptothecin. Drug treatment of c-myc–overexpressing cells in the absence of IL-3 did not alter the spectrum of drug sensitivity other than to additively accelerate cell death. In contrast, enhanced sensitivity to Adriamycin, Etoposide, and Taxol (Bristol-Meyers Squibb, Princeton, NJ) was revealed in max-overexpressing cells concurrently deprived of IL-3. Differential rates of apoptosis were not strictly correlated with the ability of the drugs to promote G1 or G2/M arrest. Ectopic expression of Bcl-2 or Bcl-XL blocked drug-induced apoptosis in both cell lines. In contrast, whereas Bcl-2 blocked apoptosis in both cell lines in response to IL-3 withdrawal, Bcl-XL blocked apoptosis in max-overexpressing cells but not in c-myc–overexpressing cells. These results provide mechanistic underpinnings for the idea that c-myc and max modulate distinct apoptotic pathways.© 1998 by The American Society of Hematology.
FLT-3 Ligand Provides Hematopoietic Protection From Total Body Irradiation in Rabbits
Authors: Gratwohl A. , John L. , Baldomero H. , Roth J. , Tichelli A. , Nissen C. , Lyman S.D. , Wodnar-Filipowicz A. 
Published: October 2019

Several hematopoietic cytokines have been investigated for their potential to provide protection from the lethal consequences of bone marrow aplasia after total body irradiation (TBI). Some can increase the dose of irradiation tolerated by the animals; none allow endogenous recovery after doses such as administered in clinical blood or marrow transplantation. We tested the radioprotective potential of FLT-3 ligand, an early acting hematopoietic cytokine, alone and in combination with a late acting cytokine, granulocyte-colony stimulating factor (G-CSF). Adult outbred New Zealand White rabbits were submitted to TBI of 1,200 or 1,400 cGy by a Co60 source. Recombinant human (rh) FLT-3 ligand at a dose of 500 μg/kg and/or rhG-CSF at a dose of 10 μg/kg were administered for 14 days subcutaneously daily, beginning either 2 days before or the day after TBI. All control animals given no growth factors died of aplasia at day 10 (range, 5 to 16). All 8 animals given G-CSF had severe aplasia and 7 died at day 8 (range, 5 to 10); 1 animal survived, with G-CSF being administered before TBI. In contrast, 11 of 12 animals given FLT-3 ligand, with or without G-CSF, survived. Radioprotection was best in the group given FLT-3 ligand together with G-CSF before TBI. In these animals median platelet counts were never <10 × 109/L and median white blood cell counts never <0.5 × 109/L. These data show that hematopoietic recovery can occur after 1,400 cGy TBI in rabbits, if protected by FLT-3 ligand, and suggest a radioprotective clinical potential of this cytokine.© 1998 by The American Society of Hematology.
Presence of a p53 Gene Deletion in Patients With Multiple Myeloma Predicts for Short Survival After Conventional-Dose Chemotherapy
Authors: Drach Johannes , Ackermann Jutta , Fritz Elke , Krömer Elisabeth , Schuster Rudolf , Gisslinger Heinz , DeSantis Maria , Zojer Niklas , Fiegl Michael , Roka Sebastian , Schuster Judith , Heinz Renate , Ludwig Heinz , Huber Heinz 
Published: October 2019

In multiple myeloma (MM), previous studies showed that mutations of the p53 gene are rare events in patients with newly diagnosed disease, but it is not known whether deletions of p53 are of any significance in MM. To address this question, we used interphase fluorescence in situ hybridization (FISH) with a DNA probe specific for the p53 locus at 17p13 and investigated bone marrow plasma cells from 72 patients with MM (59 patients = 81.9% before therapy). By FISH, deletions of p53, which were found to be predominantly monoallelic, were detected in 32.8% and 54.5% of patients with newly diagnosed and relapsed MM, respectively. Karyotypes from six of the patients with a p53 deletion by FISH showed a structural abnormality of 17p in only one of them. Additional FISH studies including a distal-17p probe (specific for theD17S34 locus) provided evidence for an interstitial deletion on 17p resulting in loss of p53 hybridization signals in myeloma cells. Among all 59 patients with newly diagnosed MM, presence of a p53 deletion was associated with stage III (P = .054), but not with other laboratory and clinical parameters. Patients with a p53 deletion had significantly shorter survival time compared with those without a deletion, both from the time of diagnosis (median 13.9v 38.7 months; P < .0001) and from the time of initiation of induction treatment consisting of conventional dose chemotherapy (median 15.9 months v median not reached at 38 months; P < .0002). On stepwise multivariate regression analysis, presence of a p53 deletion was the most significant independent parameter predicting for shortened survival (P = .002). We conclude that a p53 gene deletion, which can be identified by interphase FISH in almost a third of patients with newly diagnosed MM, is a novel prognostic factor predicting for short survival of MM patients treated with conventional-dose chemotherapy.
© 1998 by The American Society of Hematology.
Exclusion of the First EGF Domain of Factor VII by a Splice Site Mutation Causes Lethal Factor VII Deficiency
Authors: McVey John H. , Boswell Emma J. , Takamiya Osamu , Tamagnini Gabriel , Valente Victor , Fidalgo Teresa , Layton Mark , Tuddenham Edward G.D. 
Published: October 2019

We have studied a family with homozygous lethal, blood coagulation factor VII (FVII) deficiency. To identify the mutation responsible for the deficiency, exons 2 to 8 and the intron-exon junctions of their FVII genes were amplified from peripheral white blood cell DNA by polymerase chain reaction and screened by single-strand conformational polymorphism analysis. The fragment showing aberrant mobility was cloned and sequenced. We detected a single point mutation, a homozygous G to A substitution at nucleotide position 6070, in the invariant GT dinucleotide at the 5′ splice site of intron 4. Homozygosity was confirmed by loss of a site for the restriction endonuclease Mlu I. Analysis of the splicing pattern of ectopic transcripts in lymphocytes in the parents revealed that this mutation is associated with skipping of exon 4, which produces an mRNA encoding FVII with an in-frame deletion of the first epidermal growth factor–like domain (EGF 1). Transient transfection of COS-7 cells with an expression vector containing the ▵EGF 1 FVII cDNA shows that this mutant protein is not expressed. The identification of the molecular basis of the FVII deficiency in this family allowed mutation-specific prenatal diagnosis to be performed in a subsequent pregnancy. In this family complete FVII deficiency is associated with a severe bleeding diathesis but no developmental abnormalities, lending weight to the hypothesis that fetal FVII is not required for the putative angiogenic functions of tissue factor in humans.© 1998 by The American Society of Hematology.
Effect of Steroid Hormones and Retinoids on the Formation of Capillary-Like Tubular Structures of Human Microvascular Endothelial Cells in Fibrin Matrices Is Related to Urokinase Expression
Authors: Lansink Mirian , Koolwijk Pieter , van Hinsbergh Victor , Kooistra Teake 
Published: October 2019

Angiogenesis, the formation of new capillary blood vessels, is a feature of a variety of pathological processes. To study the effects of a specific group of hormones (all ligands of the steroid/retinoid/thyroid hormone receptor superfamily) on the angiogenic process in humans, we have used a model system in which human microvascular endothelial cells from foreskin (hMVEC) are cultured on top of a human fibrin matrix in the presence of basic fibroblast growth factor and tumor necrosis factor-α. This model mimics the in vivo situation where fibrin appears to be a common component of the matrix present at sites of chronic inflammation and tumor stroma. Our results show that testosterone and dexamethasone are strong inhibitors and all-trans retinoic acid (at-RA) and 9-cis retinoic acid (9-cis RA) are potent stimulators of the formation of capillary-like tubular structures. These effects are mediated by their respective nuclear hormone receptors as demonstrated by the use of specific synthetic receptor agonists and antagonists. 17β-estradiol, progesterone, and 1,25-dihydroxyvitamin D3 did not affect or only weakly affected in vitro angiogenesis, which may be related to the lack of significant nuclear receptor expression. Although hMVEC express both thyroid hormone receptors α and β, no effect of thyroid hormone on tube formation was found. The effects of testosterone, dexamethasone,at-RA, and 9-cis RA on tube formation were accompanied by parallel changes in urokinase-type plasminogen activator (u-PA) expression, at both mRNA and antigen levels. Exogenous suppletion of the medium with single chain u-PA enhances tube formation in our in vitro model, whereas quenching of u-PA activity (but not of tissue-type plasminogen activator activity) or of u-PA binding to u-PA receptor by specific antibodies suppressed basal and retinoid-stimulated tube formation. Moreover, addition of scu-PA to testosterone- or dexamethasone-treated hMVEC restored the suppressed angiogenic activity for a substantial part. Aprotinin, an inhibitor of plasmin activity, completely inhibited tube formation, indicating that the proteolytic properties of the u-PA/u-PA receptor complex are crucial in this process. Our results show that steroid hormones (testosterone and dexamethasone) and retinoids have strong, but opposite effects on tube formation in a human in vitro model reflecting pathological angiogenesis in the presence of fibrin and inflammatory mediators. These effects can be explained by hormone-receptor–mediated changes in u-PA expression, resulting in enhanced local proteolytic capacity of the u-PA/u-PA receptor complex.© 1998 by The American Society of Hematology.
Adenosine Triphosphate–Induced Shedding of CD23 and L-Selectin (CD62L) From Lymphocytes Is Mediated by the Same Receptor but Different Metalloproteases
Authors: Gu B. , Bendall L.J. , Wiley J.S. 
Published: October 2019

CD23 is a transmembrane protein expressed on the surface of B-lymphocytes that binds IgE, CD21, CD11b, and CD11c. High concentrations of soluble CD23 and L-selectin are found in the serum of patients with B-chronic lymphocytic leukemia (B-CLL). Because extracellular adenosine triphosphate (ATP) causes shedding of L-selectin via activation of P2Z/P2X7 receptors expressed on B-CLL lymphocytes, we studied the effect of ATP on shedding of CD23. ATP-induced shedding of CD23 at an initial rate of 12% of that for L-selectin, whereas the EC50 for ATP was identical (35 μmol/L) for shedding of both molecules. Furthermore, benzoylbenzoyl ATP also produced shedding of CD23 and L-selectin with the same agonist EC50 values for both (10 μmol/L). Inactivation of the P2Z/P2X7 receptor by preincubation with oxidized ATP abolished ATP-induced shedding of both molecules. Moreover, KN-62, the most potent inhibitor for the P2Z/P2X7 receptor, inhibited ATP-induced shedding of both CD23 and L-selectin with the same IC50 (12 nmol/L). Ro 31-9790, a membrane permeant zinc chelator that inhibits the phorbol-ester-stimulated shedding of L-selectin, also inhibited shedding of CD23 from B-CLL lymphocytes. However, the IC50 for this inhibition by Ro31-9790 was different for L-selectin and CD23 (83 v 6 μmol/L, respectively). Although L-selectin was completely shed by incubation of cells with phorbol-ester, CD23 was not lost under these conditions. The data show that extracellular ATP induces shedding of L-selectin and CD23 from B-CLL lymphocytes by an action mediated by the P2Z/P2X7 receptor. However, different membrane metalloproteases seem to mediate the shedding of L-selectin and CD23.© 1998 by The American Society of Hematology.
Long-Term Follow-Up of Patients With Chronic Lymphocytic Leukemia (CLL) Receiving Fludarabine Regimens as Initial Therapy
Authors: Keating M.J. , O’Brien S. , Lerner S. , Koller C. , Beran M. , Robertson L.E. , Freireich E. J , Estey E. , Kantarjian H. 
Published: October 2019

One hundred seventy-four patients with progressive or advanced chronic lymphocytic leukemia (CLL) have received initial therapy with fludarabine as a single agent or fludarabine combined with prednisone. The overall response rate was 78% and the median survival was 63 months. No difference in response rate or survival was noted in the 71 patients receiving fludarabine as a single agent compared with the 103 patients who received prednisone in addition. The median time to progression of responders was 31 months and the overall median survival was 74 months. Patients over the age of 70 years had shorter survivals. Patients with advanced stage disease (Rai III and IV) had a somewhat shorter survival than earlier stage patients. More than half the patients who relapsed after fludarabine therapy responded to salvage treatment, usually with fludarabine-based regimens. Second remissions were more common in patients who had achieved a complete remission on their initial treatment. The CD4 and CD8 T-lymphocyte subpopulations decreased to levels in the range of 150 to 200/μL after the first 3 courses of treatment. Although recovery towards normal levels was slow, the incidence of infections was low in patients in remission (1 episode of infection for every 3.33 patient years at risk) and decreased with time off treatment. There was no association of infections or febrile episodes with the use of corticosteroids or the CD4 count at the end of treatment and a poor correlation with the increase in CD4 counts during remission. Infectious episodes were less common in patients who had a complete response compared with partial responders. Richter’s transformation occurred in 9 patients and Hodgkin’s disease occurred in 4 patients. Five other patients died from other second malignancies. Fludarabine appears to be an effective initial induction therapy with a reasonable safety profile for patients with CLL.
© 1998 by The American Society of Hematology.