bluuebunny/crossref_metadata_2025_split huggingface dataset:
Juvenile development and life cycle of Heterorhabditis bacteriophora and H. indica (Nematoda: Heterorhabditidae)
Authors: Johnigk Stefan-Andreas , Ehlers Ralf-Udo 
Published: July 2002

AbstractHeterorhabditis bacteriophora and H. indica were cultured in vitro in monoxenic liquid cultures. Nematodes were examined for morphological characters which can be used to determine the sexes in all juvenile stages. When hatching from the egg no sex-specific characters could be distinguished. Twelve hours later sex determination resulted in male phenotypes which were identified by the asymmetric shape of the primordial testis. Female phenotypes, with symmetrical primordial gonads, were observed 12 h later. Of the eggs laid by the parental hermaphrodite 57% developed to amphimictic adults. The other individuals were determined to become automictic dauer juveniles which further develop to hermaphrodites. The pre-dauer J1 was the last of the first juvenile stages to be determined. They moult to the pre-dauer second stage juvenile (J2D) which is distinguished from the other J2 stages by a thin and spindle-like shape, elongated pharynx and needle-like tip of the tail. The late JD2 stage is immobile, pharyngeal pumping ceases and intercalated fat reserves make it appear darker then the amphimictic J2. The further development to adults is described and the occurrence of the different stages in liquid culture documented. Developpement larvaire et cycle biologique d'Heterorhabditis bacteriophora et H. indica (Nematoda: Heterorhabditidae) - Heterorhabditis bacteriophora and H. indica ont ete eleves in vitro sur milieux liquides monoxeniques. Les nematodes ont ete etudies pour les caracteres morphologiques qui pourraient etre utilises dans la determination des sexes dans tous les stades juveniles. A l'eclosion, aucun caractere sexuel specifique n'a pu etre identifie. Douze heures plus tard, le dimorphisme sexuel se revele avec des phenotypes males caracterises par la forme asymetrique du testicule. Les phenotypes femelles avec des primordium symetriques ont ete observes 12 h plus tard. 57% des individus issus des oeufs de parent hermaphrodite se sont developpes en adulte amphimictique. Les autres individus se sont developpes en dauerlarva automictiques qui se sont plus tard developpes en hermaphrodites. La pre-dauerlarvae (J1) a ete le dernier des stades juveniles a etre identifie. Ils ont mue en stade pre-dauer J2 qui peut etre differencie des autres stades J2 par le corps mince et fusiforme, un pharynx allonge et l'extemite de la queue tres effilee. Le dernier stade DJ2 est immobile, le pompage pharyngien cesse et des reserves lipidiques interstitielles le rendent plus sombre que chez le stade amphimictique J2. Le developpement jusqu'a l'adulte est decrit et l'apparition de differents stades en milieu de culture liquide est detaillee.
LDH-derived catalysts for complete oxidation of volatile organic compounds
Authors: Bahranowski K. , Bielańska E. , Janik R. , Machej T. , Serwicka E. M. 
Published: July 2002

AbstractThe Cu,Cr-, Zn,Cr- and Cu,Al-layered double hydroxides have been synthesized by the coprecipitation method and characterized by elemental analysis, PXRD, SEM/EDS and BET. The mixed oxide materials obtained upon calcination at 873 K show very high catalytic activity for the combustion of toluene and ethanol. The best sample is derived from the Cu,Cr-LDH precursor with a Cu:Cr ratio of 2, composed of copper oxide and copper chromite. This catalyst gave 50% conversion of toluene and ethanol at temperatures of 45 and 15 K lower, respectively, than the reference commercial catalyst. Catalytic tests with a mechanical mixture of CuO and CuCr2O4 demonstrate that the use of an LDH precursor is essential for optimum results. The importance of the simultaneous presence of both Cu and Cr, the influence of the Cu:Cr ratio on the catalytic activity and the role of the interface boundaries in the CuO-CuCr2O4 mixed oxide system are discussed.
CL for characterizing quartz and trapped fluid inclusions in mesothermal quartz veins: Muruntau Au ore deposit, Uzbekistan
Authors: Graupner T. , Götze J. , Kempe U. , Wolf D. 
Published: July 2002

AbstractCombined cathodoluminescence (CL) and transmitted light microscopy were used to characterize quartz from flat and steeply dipping quartz veins and from veinlets in banded host rocks from the giant Muruntau Au quartz vein deposit, Kyzyl Kum Desert, western Uzbekistan. The CL examinations were carried out using a ‘hot-cathode’ CL microscope linked to a highly sensitive digital video camera. The multi-stage deformed flat quartz veins and the steeply dipping hydrothermal formations at Muruntau are characterized by quartz with different CL colours, internal structures and degree of secondary alteration. Primary growth zoning of quartz, indiscernible in conventional polarized light was found to occur only in steeply dipping veins. The bulk of the high-grade Au mineralized ‘central’ quartz veins is dominated by one generation of hydrothermal quartz; intense brecciation of these veins is indicated by the occurrence of fragments of zoned quartz crystals. Primary growth zoning in quartz may be revealed not only by variations in the intensity of blue CL and/or by primary fluid inclusions arranged within the zones, but also by secondary inclusions and recrystallization phenomena developed along boundary surfaces between the zones. Using the results from CL imaging and microstructural analysis of the quartz, fluid inclusions investigated earlier were assigned to genetic types; the evidence of probably primary inclusions is of considerable importance for further studies of the geochemical conditions during vein formation. Considering geological and mineralogical data, CL studies of vein quartz may help to reveal the history of precipitation, deformation and recrystallization processes in the Muruntau Au ore field.
Phase relations in the metal-rich portions of the phase system Pt-Ir-Fe-S at 1000°C and 1100°C
Authors: Makovicky E. , Karup-Møller S. 
Published: July 2002

AbstractPhase relations in the S-poor portions of the dry condensed Pt-Ir-Fe-S system were determined at 1000° and 1100°C with a particular emphasis on delineation of the solid solubility fields of the Pt-Ir-Fe alloys. At both temperatures, a broad field of γ(Ir,Fe,Pt) alloy coexists with γ-(Pt,Fe), Pt3Fe and PtFe which dissolve respectively at least 5.1, 29.3 and 24.0 at.% Ir at 1100°C (2.2, 23.6 and ≤17.2 at.% Ir at 1000°C). Gaps between the nearly Ir-free Pt-Fe alloys γ(Pt,Fe), Pt3Fe s.s., PtFe s.s. and γ(Fe,Pt) were estimated as 20–23 at.%, 40–42 at.% and 54.2–~57 at.% Fe at 1100°C (18–23, 39.5–42.5 and 59–62 at.% Fe at 1000°C). The first gap agrees with data from natural phases by Cabri et al. (1996). The Fe-rich sulphide melt dissolves only traces of Pt and Ir; Fe1–xS dissolves up to 5.8 at.% Ir at 1100°C and 3.4 at.% Ir at 1000°C. These solubilities and the compositions of coexisting alloys (before low-temperature exsolution) may serve as geothermometers. The S-rich melt dissolves up to 8.2 at.% Pt and 2.5 at.% Ir (measured on a solidified melt) at 1100°C. The Fe-Ir thiospinel dissolves up to 2.2 at.% Pt (for the composition Fe21.6Ir18.9Pt2.2S57.3 at 1100°C). The 25–28 at.% Fe portions of Pt3Fe with <10 at.% Ir partake in all important sulphide (± melt)-alloy assemblages (with PtS, Ir2S3, pyrrhotite, S-rich melt and thiospinel). Therefore, their use in recognizing distinct natural assemblages of genetic importance is of limited value.
Lentivirus-transduced human monocyte-derived dendritic cells efficiently stimulate antigen-specific cytotoxic T lymphocytes
Authors: Dyall Julie , Latouche Jean-Baptiste , Schnell Stefan , Sadelain Michel 
Published: July 2002

AbstractDendritic cells (DCs) are professional antigen-presenting cells that are highly effective adjuvants for immunizing against pathogens and tumor antigens. The potential merit of genetic approaches to loading DCs with antigens is to express high and sustained levels of proteins that can be subsequently processed and presented to T lymphocytes. Replication-defective oncoretroviruses are able to efficiently transduce CD34+ progenitor-derived DCs but not monocyte-derived DCs. Here, it is shown that efficient gene transfer is obtained using a human immunodeficiency virus-1–derived lentiviral vector deleted of all structural and accessory genes. Infection of immature DCs with the lentiviral vector at a multiplicity of infection of 20 resulted in stable gene expression in 30% to 40% of the matured DCs. Proviral DNA was detectable by Alu polymerase chain reaction for the lentiviral but not the oncoretroviral vector. Most importantly, it is demonstrated that lentivirus-transduced DCs were fully functional and effectively activated autologous HLA A2.1+ peripheral blood cytotoxic T lymphocytes (CTLs). DCs expressing lentiviral vector-encoded Flu peptide were at least as efficient as DCs pulsed with the same peptide in stimulating specific CTLs. The efficacy of the lentivirus-transduced DCs was further demonstrated by their ability to directly activate freshly harvested peripheral blood Flu-specific CTLs in the absence of CD4+ T-cell help and exogenous cytokines. The availability of a stable gene delivery system based on a multiply attenuated lentivirus that does not encode any viral protein and that allows sustained antigen presentation by DCs derived from blood monocytes will be very useful for the biologic investigation of DCs and the improvement of immunotherapeutic strategies involving DCs.
c-mpl mutations are the cause of congenital amegakaryocytic thrombocytopenia
Authors: Ballmaier Matthias , Germeshausen Manuela , Schulze Harald , Cherkaoui Klara , Lang Sabine , Gaudig Annika , Krukemeier Stephanie , Eilers Martin , Strauß Gabriele , Welte Karl 
Published: July 2002

Abstract
Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare disease presenting with isolated thrombocytopenia in infancy and developing into a pancytopenia in later childhood. Thrombopoietin (TPO) is the main regulator of thrombocytopoiesis and has also been demonstrated to be an important factor in early hematopoiesis. We analyzed 9 patients with CAMT for defects in TPO production and reactivity. We found high levels of TPO in the sera of all patients. However, platelets and hematopoietic progenitor cells of patients with CAMT did not show any reactivity to TPO, as measured by testing TPO-synergism to adenosine diphosphate in platelet activation or by megakaryocyte colony assays. Flow cytometric analysis revealed absent surface expression of the TPO receptor c-Mpl in 3 of 3 patients. Sequence analysis of the c-mpl gene revealed point mutations in 8 of 8 patients: We found frameshift or nonsense mutations that are predicted to result in a complete loss of c-Mpl function in 5 patients. Heterozygous or homozygous missense mutations predicted to lead to amino acid exchanges in the extracellular domain of the receptor were found in 3 other patients. The type of mutations correlated with the clinical course of the disease. We propose a defective c-Mpl expression due to c-mpl mutations as the cause for thrombocytopenia and progression into pancytopenia seen in patients with CAMT.
Chemokine stromal cell-derived factor-1α modulates VLA-4 integrin-mediated multiple myeloma cell adhesion to CS-1/fibronectin and VCAM-1
Authors: Sanz-Rodrı́guez Francisco , Hidalgo Andrés , Teixidó Joaquin 
Published: July 2002

AbstractThe chemokine stromal cell-derived factor-1α (SDF-1α) and its G-protein–linked receptor CXCR4 are involved in hematopoietic progenitor cell and lymphocyte migration. The integrin VLA-4 is a cell adhesion receptor for CS-1/fibronectin and VCAM-1 and constitutes one of the main adhesion receptors mediating myeloma cell adhesion to bone marrow (BM) stroma in multiple myeloma (MM). It is shown here that MM CD38hiCD45RA− BM cells and myeloma-derived cell lines expressed CXCR4 and displayed a moderate chemotactic response to SDF-1α. Because cell migration in response to SDF-1α might require a dynamic regulation of integrin function, it was investigated whether SDF-1α can modulate VLA-4 function on myeloma cells. SDF-1α rapidly and transiently up-regulated VLA-4–mediated myeloma cell adhesion to both CS-1/fibronectin and VCAM-1, which was inhibited by pertussis toxin and cytochalasin D, indicating the involvement of Gi protein downstream signaling and an intact cytoskeleton. Modulation of VLA-4–dependent myeloma cell adhesion by SDF-1α could contribute to the trafficking and localization of these cells in the BM microenvironment.
HIV-1 Tat promotes monocyte chemoattractant protein-1 secretion followed by transmigration of monocytes
Authors: Park In-Woo , Wang Jian-Feng , Groopman Jerome E. 
Published: July 2002

AbstractThe mechanism whereby HIV-infected cells transit from the bloodstream into tissues is not well defined. This phenomenon was addressed by studying the effects of HIV-1 Tat, a protein secreted by infected cells, on human lung microvascular endothelial cells (HMVEC-Ls). It was found that monocyte chemoattractant protein-1 (MCP-1) was released from HMVEC-Ls in a dose- and time-dependent manner after Tat treatment. MCP-1 is a potent β-chemokine that recruits monocytes and T cells and promotes cell adhesion and transmigration across an endothelial monolayer. It was also observed that MCP-1 and the culture medium from Tat-treated HMVEC-Ls were chemotactic for CD14+ monocytes from human peripheral blood and for THP-1, a promonocytic cell line used as a model system. To characterize the signaling pathways underlying the observed induction of MCP-1, HMVEC-Ls were treated with 2 different protein kinase inhibitors: PD98059, a MAP kinase inhibitor, and GF109203X, a protein kinase C (PKC) inhibitor. MCP-1 release was significantly reduced when PKC was inhibited, and slightly decreased when PI3 kinase was blocked; no effect on MCP-1 release was observed on MAP kinase inhibition. Similarly, transmigration of THP-1 cells was significantly impaired by the PKC inhibitor, but not by the other tested inhibitors. These data indicate that the HIV-1 Tat protein may act as a protocytokine by causing the release of MCP-1 from the endothelial monolayer, and thereby facilitating monocyte transmigration into tissues via a PKC signaling pathway.
Requirement of Shp-2 tyrosine phosphatase in lymphoid and hematopoietic cell development
Authors: Qu Cheng-Kui , Nguyen Suzanne , Chen Jianzhu , Feng Gen-Sheng 
Published: July 2002

Abstract
Shp-1 and Shp-2 are cytoplasmic phosphotyrosine phosphatases with similar structures. Mice deficient in Shp-2 die at midgestation with defects in mesodermal patterning, and a hypomorphic mutation at the Shp-1 locus results in the moth-eaten viable (mev) phenotype. Previously, a critical role of Shp-2 in mediating erythroid/myeloid cell development was demonstrated. By using the RAG-2–deficient blastocyst complementation, the role of Shp-2 in lymphopoiesis has been determined. Chimeric mice generated by injecting Shp-2−/− embryonic stem cells into Rag-2–deficient blastocysts had no detectable mature T and B cells, serum immunoglobulin M, or even Thy-1+ and B220+ precursor lymphocytes. Collectively, these results suggest a positive role of Shp-2 in the development of all blood cell lineages, in contrast to the negative effect of Shp-1 in this process. To determine whether Shp-1 and Shp-2 interact in hematopoiesis, Shp-2−/−:mev/mev double-mutant embryos were generated and the hematopoietic cell development in the yolk sacs was examined. More hematopoietic stem/progenitor cells were detected in Shp-2−/−:mev/mevembryos than in Shp-2−/− littermates. The partial rescue by Shp-1 deficiency of the defective hematopoiesis caused by the Shp-2 mutation suggests that Shp-1 and Shp-2 have antagonistic effects in hematopoiesis, possibly through a bidirectional modulation of the same signaling pathway(s).
Core-binding factor β (CBFβ), but not CBFβ–smooth muscle myosin heavy chain, rescues definitive hematopoiesis in CBFβ-deficient embryonic stem cells
Authors: Miller Janelle D. , Stacy Terryl , Liu P. Paul , Speck Nancy A. 
Published: July 2002

AbstractCore-binding factor β (CBFβ) is the non–DNA-binding subunit of the heterodimeric CBFs. Genes encoding CBFβ (CBFB),and one of the DNA-binding CBFα subunits, Runx1 (also known as CBFα2, AML1, and PEBP2αB), are required for normal hematopoiesis and are also frequent targets of chromosomal translocations in acute leukemias in humans. Homozygous disruption of either the Runx1or Cbfb gene in mice results in embryonic lethality at midgestation due to hemorrhaging in the central nervous system, and severely impairs fetal liver hematopoiesis. Results of this study show that Cbfb-deficient mouse embryonic stem (ES) cells can differentiate into primitive erythroid colonies in vitro, but are impaired in their ability to produce definitive erythroid and myeloid colonies, mimicking the in vivo defect. Definitive hematopoiesis is restored by ectopic expression of full-length Cbfbtransgenes, as well as by a transgene encoding only the heterodimerization domain of CBFβ. In contrast, the CBFβ–smooth muscle myosin heavy chain (SMMHC) fusion protein generated by the inv(16) associated with acute myeloid leukemias (M4Eo) cannot rescue definitive hematopoiesis by Cbfb-deficient ES cells. Sequences responsible for the inability of CBFβ-SMMHC to rescue definitive hematopoiesis reside in the SMMHC portion of the fusion protein. Results also show that the CBFβ-SMMHC fusion protein transdominantly inhibits definitive hematopoiesis, but not to the same extent as homozygous loss of Runx1 orCbfb. CBFβ-SMMHC preferentially inhibits the differentiation of myeloid lineage cells, while increasing the number of blastlike cells in culture.
Echicetin, a GPIb-binding snake C-type lectin from Echis carinatus, also contains a binding site for IgMκ responsible for platelet agglutination in plasma and inducing signal transduction
Authors: Navdaev Alexei , Dörmann Dagmar , Clemetson Jeannine M. , Clemetson Kenneth J. 
Published: July 2002

AbstractEchicetin, a heterodimeric snake C-type lectin from Echis carinatus, is known to bind specifically to platelet glycoprotein (GP)Ib. We now show that, in addition, it agglutinates platelets in plasma and induces platelet signal transduction. The agglutination is caused by binding to a specific protein in plasma. The protein was isolated from plasma and shown to cause platelet agglutination when added to washed platelets in the presence of echicetin. It was identified as immunoglogulin Mκ (IgMκ) by peptide sequencing and dot blotting with specific heavy and light chain anti-immunoglobulin reagents. Platelet agglutination by clustering echicetin with IgMκ induced P-selectin expression and activation of GPIIb/IIIa as well as tyrosine phosphorylation of several signal transduction molecules, including p53/56LYN, p64, p72SYK, p70 to p90, and p120. However, neither ethylenediaminetetraacetic acid nor specific inhibition of GPIIb/IIIa affected platelet agglutination or activation by echicetin. Platelet agglutination and induction of signal transduction could also be produced by cross-linking biotinylated echicetin with avidin. These data indicate that clustering of GPIb alone is sufficient to activate platelets. In vivo, echicetin probably activates platelets rather than inhibits platelet activation, as previously proposed, accounting for the observed induction of thrombocytopenia.
Survival of leukemic B cells promoted by engagement of the antigen receptor
Authors: Bernal Alejandro , Pastore Raymond D. , Asgary Zahra , Keller Shannon A. , Cesarman Ethel , Liou Hsiou-Chi , Schattner Elaine J. 
Published: July 2002

AbstractChronic lymphocytic leukemia (CLL) is an incurable leukemia characterized by the slow but progressive accumulation of cells in a CD5+ B-cell clone. Like the nonmalignant counterparts, B-1 cells, CLL cells often express surface immunoglobulin with the capacity to bind autologous structures. Previously there has been no established link between antigen-receptor binding and inhibition of apoptosis in CLL. In this work, using primary CLL cells from untreated patients with this disease, it is demonstrated that engagement of surface IgM elicits a powerful survival program. The response includes inhibition of caspase activity, activation of NF-κB, and expression of mcl-1, bcl-2, and bfl-1 in the tumor cells. Blocking phosphatidylinositol 3-kinase (PI3-K), a critical mediator of signals through the antigen receptor, completely abrogated mcl-1 induction and impaired survival in the stimulated cells. These data support the contention that CLL cell survival is promoted by antigen for which the malignant clone has affinity, and suggest that pharmacologic interference with antigen-receptor–derived signals has potential for therapy in patients with CLL.
Fetal liver myelopoiesis occurs through distinct, prospectively isolatable progenitor subsets
Authors: Traver David , Miyamoto Toshihiro , Christensen Julie , Iwasaki-Arai Junko , Akashi Koichi , Weissman Irving L. 
Published: July 2002

AbstractHematopoietic fate maps in the developing mouse embryo remain imprecise. Definitive, adult-type hematopoiesis first appears in the fetal liver, then progresses to the spleen and bone marrow. Clonogenic common lymphoid progenitors and clonogenic common myeloid progenitors (CMPs) in adult mouse bone marrow that give rise to all lymphoid and myeloid lineages, respectively, have recently been identified. Here it is shown that myelopoiesis in the fetal liver similarly proceeds through a CMP equivalent. Fetal liver CMPs give rise to megakaryocyte–erythrocyte-restricted progenitors (MEPs) and granulocyte–monocyte-restricted progenitors (GMPs) that can also be prospectively isolated by cell surface phenotype. MEPs and GMPs generate mutually exclusive cell types in clonogenic colony assays and in transplantation experiments, suggesting that the lineage restriction observed within each progenitor subset is absolute under normal conditions. Purified progenitor populations were used to analyze expression profiles of various hematopoiesis-related genes. Expression patterns closely matched those of the adult counterpart populations. These results suggest that adult hematopoietic hierarchies are determined early in the development of the definitive immune system and suggest that the molecular mechanisms underlying cell fate decisions within the myeloerythroid lineages are conserved from embryo to adult.