bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of in vitro growth conditions for c-Kit–negative hematopoietic stem cells
Authors: Klarmann Kim , Ortiz Mariaestela , Davies Meghan , Keller Jonathan R. 
Published: July 2003

AbstractOur laboratory recently identified a quiescent class of pluripotent hematopoietic stem cells (PHSCs) that are lineage negative (Linneg), lack c-Kit, and are able to give rise to c-Kit–positive (c-Kitpos) PHSCs in vivo. This population fails to proliferate in vitro but has delayed reconstituting activity in vivo. In this study, we purified these cells to enrich for the PHSCs and we identified in vitro conditions capable of supporting their maturation. The c-Kit–negative (c-Kitneg) cells exhibited differential expression of Sca-1, CD34, CD43, CD45, and Thy 1.2. We purified the cells based on Sca-1, as it is expressed on active PHSCs. We detected pre–colony-forming unit spleen (pre–CFU-s) activity in both the Sca-1neg and Sca-1pos populations, indicating the presence of primitive PHSCs in both populations. However, our in vitro studies suggest that the Sca-1pos population is enriched for PHSCs. The in vitro systems that support the growth of these dormant cells include a modified long-term marrow culture and various stromal cell lines. In modified long-term bone marrow cultures, c-Kitneg cells gave rise to c-Kitpos PHSCs, with long-term reconstitution activity in vivo. Thus we have established an in vitro system to examine PHSC maturation that will allow us to study the mediators of the c-Kitneg to c-Kitpos transition.
Ifosfamide impairs the allostimulatory capacity of human dendritic cells by intracellular glutathione depletion
Authors: Kuppner Maria C. , Scharner Anabel , Milani Valeria , von Hesler Christoph , Tschöp Katharina E. , Heinz Oksana , Issels Rolf D. 
Published: July 2003

AbstractIfosfamide, a clinically potent chemotherapeutic agent, causes the depletion of intracellular glutathione (GSH) levels in various cell types. GSH is the major intracellular reductant against oxidative stress. 4-Hydroxyifosfamide (4-OH-IF), the activated form of ifosfamide, depletes GSH levels in T cells and natural killer (NK) cells; this is accompanied by a decrease in T-cell and NK-cell function. Here we demonstrate for the first time that human monocyte-derived dendritic cells (DCs) express higher constitutive levels of GSH and are less sensitive to 4-OH-IF-induced GSH depletion than T cells and NK cells. Treatment of DCs with 4-OH-IF significantly reduced their ability to stimulate allogeneic T-cell proliferation and interferon-γ (IFN-γ) production. Ifosfamide also decreased DC interleukin-12p70 (IL-12p70) production after stimulation with lipopolysaccharide (LPS) and IFN-γ. The decrease in allostimulatory capacity and in IFN-γ and IL-12 production correlated with a decrease in intracellular GSH in the DCs. The responses could be restored by reconstituting DC GSH levels with glutathione monoethyl ester (GSH-OEt). 4-OH-IF had no inhibitory effect on the ability of DCs to present exogenously added tyrosinase peptide to tyrosinase-specific cytotoxic T lymphocytes (CTLs). These studies suggest that in cancer patients treated with ifosfamide, protection strategies based on glutathione reconstitution may enhance DC function. (Blood. 2003;102: 3668-3674)
Hsp27 inhibits release of mitochondrial protein Smac in multiple myeloma cells and confers dexamethasone resistance
Authors: Chauhan Dharminder , Li Guilan , Hideshima Teru , Podar Klaus , Mitsiades Constantine , Mitsiades Nicholas , Catley Laurence , Tai Yu Tzu , Hayashi Toshiaki , Shringarpure Reshma , Burger Renate , Munshi Nikhil , Ohtake Yasuyuki , Saxena Satya , Anderson Kenneth C. 
Published: July 2003

AbstractSmac, second mitochondria-derived activator of caspases, promotes apoptosis via activation of caspases. Heat shock protein 27 (Hsp27) negatively regulates another mitochondrial protein, cytochrome c, during apoptosis; however, the role of Hsp27 in modulating Smac release is unknown. Here we show that Hsp27 is overexpressed in both dexamethasone (Dex)-resistant multiple myeloma (MM) cell lines (MM.1R, U266, RPMI-8226) and primary patient cells. Blocking Hsp27 by an antisense (AS) strategy restores the apoptotic response to Dex in Dex-resistant MM cells by triggering the release of mitochondrial protein Smac, followed by activation of caspase-9 and caspase-3. Moreover, AS-Hsp27 overcomes interleukin-6 (IL-6)-mediated protection against Dex-induced apoptosis. These data demonstrate that Hsp27 inhibits the release of Smac, and thereby confers Dex resistance in MM cells.
Activation-induced cytidine deaminase in chronic lymphocytic leukemia B cells: expression as multiple forms in a dynamic, variably sized fraction of the clone
Authors: Albesiano Emilia , Messmer Bradley T. , Damle Rajendra N. , Allen Steven L. , Rai Kanti R. , Chiorazzi Nicholas 
Published: July 2003

AbstractThe degree of somatic mutation of immunoglobulin variable (Ig V) region genes is an important prognostic indicator of clinical course and outcome in B-cell chronic lymphocytic leukemia (B-CLL), although the reason for this association remains unclear. Furthermore, some B-CLL cells continue to acquire Ig V gene mutations after the transforming event. Because activation-induced cytidine deaminase (AID) is an essential component of the canonical somatic hypermutation process in healthy B cells, its expression in B-CLL is potentially relevant to the disease. We detected full-length AID transcripts and 3 splice variants by conventional reverse transcription polymerase chain reaction (RT-PCR) in approximately 40% of the cases examined. More sensitive real-time quantitative PCR detected AID transcripts in virtually all B-CLL samples tested, although the range of transcript levels was very large between different cases and varied within individual cases over time. Limiting dilution assays revealed that AID expression was restricted to a small fraction of the leukemic cells in the blood. However, this small fraction is not unique in its ability to express AID, because in vitro stimulation of B-CLL cells with appropriate stimuli significantly increased the fraction of AID-expressing cells. These data suggest that AID-mediated DNA alterations may occur in a variably sized, minor subset of B-CLL cells at any given time.
Risks and outcomes of idiopathic pneumonia syndrome after nonmyeloablative and conventional conditioning regimens for allogeneic hematopoietic stem cell transplantation
Authors: Fukuda Takahiro , Hackman Robert C. , Guthrie Katherine A. , Sandmaier Brenda M. , Boeckh Michael , Maris Michael B. , Maloney David G. , Deeg H. Joachim , Martin Paul J. , Storb Rainer F. , Madtes David K. 
Published: July 2003

AbstractIdiopathic pneumonia syndrome (IPS) is a significant noninfectious complication of hematopoietic stem cell transplantation (HSCT). We compared the incidences and outcomes of IPS among patients who underwent allogeneic HSCT after nonmyeloablative (n = 183) compared with conventional (n = 917) conditioning between December 1997 and December 2001. Patients given nonmyeloablative conditioning were older than those given conventional conditioning (median ages, 53 vs 41 years; P = .001). The cumulative incidence of IPS was significantly lower at 120 days after nonmyeloablative conditioning than conventional conditioning (2.2% vs 8.4%; P = .003). In addition, greater patient age (older than 40 years), diagnosis of acute leukemia or myelodys-plastic syndrome, and severe acute graft-versus-host disease were associated with significantly increased risks for IPS. Among older patients (older than 40 years) given conventional conditioning, high-dose total body irradiation (TBI) was associated with an increased risk for IPS than were non-TBI–based regimens (16% vs 5.8%; P = .001). IPS occurred early after transplantation, progressed rapidly, and was associated with a high mortality rate (75%) despite aggressive support. Initiation of mechanical ventilation and the presence of renal insufficiency at IPS onset were associated with increased risks for death after IPS. These findings support the concept that lung damage from the conditioning regimen plays a crucial role in the development of IPS after HSCT.
Nonneutralizing IgM and IgG antibodies to von Willebrand factor–cleaving protease (ADAMTS-13) in a patient with thrombotic thrombocytopenic purpura
Authors: Scheiflinger Friedrich , Knöbl Paul , Trattner Bettina , Plaimauer Barbara , Mohr Gabriele , Dockal Michael , Dorner Friedrich , Rieger Manfred 
Published: July 2003

Abstract
Acquired thrombotic thrombocytopenic purpura (TTP) has been linked to severe deficiency of ADAMTS-13 activity caused by autoantibodies inhibitory to ADAMTS-13. We report data on a patient with confirmed TTP who had severely reduced ADAMTS-13 activity but showed no ADAMTS-13 inhibition in a widely used fluid phase activity assay. With a newly developed enzyme-linked immunosorbent assay, using immobilized recombinant ADAMTS-13, we found high titers of IgM and IgG antibodies that bound to ADAMTS-13, but did not neutralize protease activity. These autoantibodies probably influenced the half-life of ADAMTS-13 or its binding to the endothelial cell surface, thereby compromising ADAMTS-13 activity in vivo. Given that ADAMTS-13 may interact physiologically with various receptors or ligands, the occurrence, distribution, and the epitope mapping of nonneutralizing antibodies will be an important area for future research.
Persistent γ-globin expression in adult transgenic mice is mediated by HPFH-2, HPFH-3, and HPFH-6 breakpoint sequences
Authors: Katsantoni Eleni Z. , Langeveld An , Wai Albert W. K. , Drabek Dubravka , Grosveld Frank , Anagnou Nicholas P. , Strouboulis John 
Published: July 2003

AbstractDeletions at the 3′ end of the human β-globin locus are associated with the hereditary persistence of fetal hemoglobin (HPFH) in adults, potentially through the juxtaposition of enhancer elements in the vicinity of the fetal γ-globin genes. We have tested how sequences at the HPFH-2, HPFH-3, and HPFH-6 breakpoints, which act as enhancers in vitro, affect the silencing of a locus control region Aγ (LCRAγ) transgene in the adult stage of mice. We found persistent Aγ expression in the adult blood of most of the multicopy HPFH-2, HPFH-3, or HPFH-6 lines, in contrast to the control LCRAγ lines which were silenced. Cre-mediated generation of single copy lines showed persistent γ gene expression maintained in some of the HPFH-2 and HPFH-6 lines, but not in any of the HPFH-3 or LCRAγ lines. In the HPFH-2 and HPFH-6 lines, persistent γ gene expression correlated with euchromatic transgene integrations. Thus, our observations provide support for a model whereby HPFH conditions arise from the juxtaposition of enhancers as well as permissive chromatin subdomains in the vicinity of the γ-globin genes.
Phase III Trial of Carboplatin and Paclitaxel Compared With Cisplatin and Paclitaxel in Patients With Optimally Resected Stage III Ovarian Cancer: A Gynecologic Oncology Group Study
Authors: Ozols Robert F. , Bundy Brian N. , Greer Benjamin E. , Fowler Jeffrey M. , Clarke-Pearson Daniel , Burger Robert A. , Mannel Robert S. , DeGeest Koen , Hartenbach Ellen M. , Baergen Rebecca 
Published: July 2003

Purpose: In randomized trials the combination of cisplatin and paclitaxel was superior to cisplatin and cyclophosphamide in advanced-stage epithelial ovarian cancer. Although in nonrandomized trials, carboplatin and paclitaxel was a less toxic and highly active combination regimen, there remained concern regarding its efficacy in patients with small-volume, resected, stage III disease. Thus, we conducted a noninferiority trial of cisplatin and paclitaxel versus carboplatin and paclitaxel in this population. Patients and Methods: Patients with advanced ovarian cancer and no residual mass greater than 1.0 cm after surgery were randomly assigned to receive cisplatin 75 mg/m2 plus a 24-hour infusion of paclitaxel 135 mg/m2 (arm I), or carboplatin area under the curve 7.5 intravenously plus paclitaxel 175 mg/m2 over 3 hours (arm II). Results: Seven hundred ninety-two eligible patients were enrolled onto the study. Prognostic factors were similar in the two treatment groups. Gastrointestinal, renal, and metabolic toxicity, as well as grade 4 leukopenia, were significantly more frequent in arm I. Grade 2 or greater thrombocytopenia was more common in arm II. Neurologic toxicity was similar in both regimens. Median progression-free survival and overall survival were 19.4 and 48.7 months, respectively, for arm I compared with 20.7 and 57.4 months, respectively, for arm II. The relative risk (RR) of progression for the carboplatin plus paclitaxel group was 0.88 (95% confidence interval [CI], 0.75 to 1.03) and the RR of death was 0.84 (95% CI, 0.70 to 1.02). Conclusion: In patients with advanced ovarian cancer, a chemotherapy regimen consisting of carboplatin plus paclitaxel results in less toxicity, is easier to administer, and is not inferior, when compared with cisplatin plus paclitaxel.
Various Phosphorylation Pathways, Depending on Agonist and Antagonist Binding to Endogenous Estrogen Receptor α (ERα), Differentially Affect ERα Extractability, Proteasome-Mediated Stability, and Transcriptional Activity in Human Breast Cancer Cells
Authors: Marsaud Véronique , Gougelet Angélique , Maillard Sébastien , Renoir Jack-Michel 
Published: July 2003

Abstract
Estrogen receptor-α (ER) is down-regulated in the presence of its cognate ligand, estradiol (E2), as well as in the presence of antiestrogens, through the ubiquitin proteasome pathway. Here, we show that, at pharmacological concentrations, the degradation rate of pure antagonist/endogenous ER complexes from human breast cancer MCF-7 cells is 10 times faster than that of ER-E2 complexes, while 4-hydroxy-tamoxifen (4-OH-T)-ER complexes are stable. Whereas pure antagonist-ER complexes are firmly bound to a nuclear compartment from which they are not extractable, the 4-OH-T-ER accumulates in a soluble cell compartment. No difference was observed in the fate of ER whether bound to pure antiestrogens ICI 182,780 or RU 58668. Cycloheximide experiments showed that, while the proteasome-mediated destruction of E2-ER (unlike that of RU 58668- and ICI 182,780-ER) complexes could implicate (or not) a protein synthesis-dependent process, both MAPKs (p38 and ERKs p44 and p42) are activated. By using a panel of kinase inhibitors/activators to study the impact of phosphorylation pathways on ER degradation, we found that protein kinase C is an enhancer of proteasome-mediated degradation of both ligand-free and ER bound to either E2, 4-OH-T, and pure antagonists. On the contrary, protein kinase A, MAPKs, and phosphatidyl-inositol-3 kinase all impede proteasome-mediated destruction of ligand free and E2-bound ER while only MAPKs inhibit the degradation of pure antiestrogens/ER species. In addition, no correlation was found between the capacity of kinase inhibitors to affect ER stability and the basal or E2-induced transcription. These results suggest that, in MCF-7 breast cancer cells, ER turnover, localization, and activity are maintained by an equilibrium between various phosphorylation pathways, which are differently modulated by ER ligands and protein kinases.
Cyclin D2 and p27 Are Tissue-Specific Regulators of Tumorigenesis in Inhibin α Knockout Mice
Authors: Burns Kathleen H. , Agno Julio E. , Sicinski Piotr , Matzuk Martin M. 
Published: July 2003

Abstract
Inhibins are heterodimeric (α:βA and α:βB) endocrine, paracrine, and autocrine factors of the TGFβ superfamily that are produced predominantly by ovarian granulosa cells in females and testicular Sertoli cells in males. Control of granulosa and Sertoli cell proliferation is lost in the inhibin α (Inhα) knockout mouse model, leading to gonadotropin-dependent gonadal tumors of the granulosa/Sertoli cell lineage in both females and males. Castrate Inhα knockout mice develop sex steroidogenic tumors of the adrenal cortex. Physiological control of granulosa/Sertoli cell cycle progression depends on p27Kip1 and cyclin D2, which function in the G1 → S phase transition. To study the cell cycle-regulatory factors involved in ovarian, testicular, and adrenal tumor development in vivo, we have bred Inhα mutant mice to mice with targeted disruptions of the p27 and cyclin D2 genes. Our previous studies demonstrated that inhibins act cooperatively with p27 to negatively regulate granulosa cell proliferation, as double mutant mice lacking inhibins and p27 develop and succumb to ovarian tumors more rapidly than Inhα knockout mice. Here, we report that cyclin D2 antagonizes this inhibition and is key in promoting gonadal growth and tumor development, and tumor development is markedly suppressed in double-mutant mice. We found that double-knockout females lacking cyclin D2 and Inhα lived longer than mice lacking inhibins alone; the majority of these double-knockout mice lived longer than 17 wk, as opposed to inhibin α single-knockout females with 50% survival at between 12 and 13 wk of age. Moreover, 95% of inhibin α knockout males succumb to testicular tumor development by 12 wk of age, whereas double knockouts were protected from early signs of tumor development and had a 50% survival of 40 wk. Interestingly, the results of these studies reflect tissue-specific consequences of loss of these cell cycle regulators. In castrate mice, loss of p27 has little effect on adrenal cortical tumor progression in the absence of inhibins, whereas loss of cyclin D2 prolongs the lifespan of cyclin D2, Inhα double knockouts. After gonadectomy, 50% of cyclin D2, Inhα double-knockout males live to more than 46 wk of age, 10 wk longer than 50% of littermates lacking only inhibins. Similarly, 50% of female cyclin D2, inhibin α double knockouts live to 47 wk of age before succumbing to adrenal tumor development, in contrast to the 50% survival of Inhα single-knockout females at between 27 and 28 wk. Thus, identification of genetic modifiers of the Inhα knockout tumor phenotype has led us to a better appreciation of how specific components of the cell cycle machinery contribute to tumorigenesis in the ovary, testis, and adrenal gland.
Facile Synthesis of a Chitosan Hybrid of a Laminin-related Peptide and Its Antimetastatic Effect in Mice
Authors: Hojo Keiko , Maeda Mitsuko , Mu Yu , Kamada Haruhiko , Tsutsumi Yasuo , Ama Yasuhiro Nishiy , Yoshikawa Tomoko , Kurita Keisuke , Block Lawrence H , Mayumi Tadanori , Kawasaki Koichi 
Published: July 2003

Abstract
Laminin, a cell adhesion protein, consists of three peptide chains (α, β and γ-1). The β chain contains a Tyr-Ile-Gly-Ser-Arg (YIGSR) sequence that has been found to inhibit experimental metastasis in mice. We have prepared a hybrid of a water-soluble chitosan and a laminin-related peptide, and have examined its inhibitory effect on experimental metastasis in mice.
A laminin-related peptide, acetyl-Tyr-Ile-Gly-Ser-Arg-βAla-OH (Ac-YIGSRβA-OH), was prepared by a solid-phase method. Ac-YIGSRβA-OH was then reacted with a watersoluble chitosan. βAla is a spacer and was placed to avoid racemization of the Arg residue when the peptide was coupled with chitosan. Although chitosan has amino groups, they did not react with the peptide. Four methods were tried to achieve a coupling reaction, the diphenylphosphoryl azide method, the diisopropylcarbodiimide/1-hydroxybenzotriazole method, the water-soluble carbodiimide (WSC), and the 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU) method, but all four methods were unsuccessful. Therefore, a small spacer, tert-butyloxycarbonyl-Gly, was intercalated in chitosan, by the TBTU method, to facilitate its coupling with the peptide. After removal of the protecting group, the Gly-chitosan was coupled with Ac-YIGSRβA-OH by the watersoluble carbodiimide method to give Ac-YIGSRβAG-chitosan.
Conjugation of the peptide with the larger chitosan molecule did not reduce the inhibitory effect of the peptide on experimental metastasis in mice, it actually potentiated the antimetastatic effect, demonstrating that chitosan may be effective as a drug carrier for peptides.
Cyclic Dipeptides in the Induction of Maturation for Cancer Therapy
Authors: Graz C J M , Grant G D , Brauns S C , Hunt A , Jamie H , Milne P J 
Published: July 2003

Abstract
Studies have suggested a possible form of therapy based on the use of maturation-inducing compounds to induce differentiation of neoplastic cells and stimulate faster recovery of the normal cell population. The study of the effects of nine cyclic dipeptides on biochemical markers of differentiation implicated their potential to induce differentiation. Studies were undertaken to determine the specificity of these agents for HT-29 cell cultures as well as the identification of the signal transduction pathways affected by these agents inducing the differential gene expression observed in the cells.
The cyclic dipeptides studied showed a high degree of specificity, having no significant effect on Caco-2 cells (P &gt; 0.05), representing the normal gastrointestinal mucosa. All inducers administered were shown to affect the total energy state of HT-29 cells, an effect which increased the probability of HT-29 cell differentiation. Results indicated that those agents which induced differential gene expression acted at different steps in the isolated signal transduction pathway. Cyclo(Trp-Trp) and cyclo(Phe-Pro) induced a high degree of acetylation of histones (P &lt; 0.05), while the remaining cyclic dipeptides induced a high degree of phosphorylation of histones (P &lt; 0.05) (cyclo(Trp-Trp) induced a moderate degree of histone phosphorylation). The results from histone phosphorylation and acetylation and cyclic AMP responsive element binding protein phosphorylation studies suggest that the cyclic dipeptides activate a chromatin switch, which leads to the increase in accessibility of lineage-specific genes for transcription.
Investigation of Endothelial Hyperreactivity in the Obese Zucker Rat In-situ: Reversal by Vitamin E
Authors: Andrews Tara J , Laight David W , Änggård Erik E , Carrier Martin J 
Published: July 2003

AbstractThe obese Zucker rat, a popular model of insulin resistance allied with oxidant stress, is associated with either normal or paradoxically enhanced endothelial vasodilator function compared with its lean litter mate. We have investigated hindquarter endothelium-dependent vasodilation in the obese Zucker rat in-situ and have examined its relationship with oxidant stress.In perfused hindquarter preparations equivalently preconstricted with phenylephrine, vasodilator responses to the endothelium-dependent agent acetylcholine (0.03–1000 pmol) were greater in obese (pD2 = 11.03±0.19) compared with lean (pD2 = 10.53±0.13) animals (P &lt; 0.01, two-way analysis of variance). In contrast, maximal vasodilation to the nitric oxide (NO) donor sodium nitroprusside (100 nmol) was similar in obese (59.6±9.8%) and lean (51.9±2.6%) preparations (P &gt; 0.05). However, this exaggerated vasodilator reactivity to acetylcholine in obese animals was abolished following four-week dietary supplementation with the lipophilic antioxidant vitamin E (obese pD2 = 10.74±0.18; lean pD2 = 10.74±0.08). This antioxidant-mediated effect was associated with a reduction (P &lt; 0.02, two-way analysis of variance) and an enhancement (P &lt; 0.01, two-way analysis of variance) in endothelium-dependent vasodilator responses in obese and lean hindlimb preparations, respectively.Our data therefore now point to a differential modulation of hindquarter endothelium-dependent vasodilation in the obese and lean Zucker rat by the prevailing oxidant tone, resulting in an agonist-stimulated endothelial vasodilator hyperreactivity in obese animals.