Human immunodeficiency virus (HIV) entry is mediated not only by the CD4 receptor, but also by interaction with closely related molecules that act as membrane coreceptors. We have analyzed mRNA ...expression and/or cell membrane exposition of the coreceptors most widely used by diverse HIV-1 strains (CXCR4, CCR5, and CCR3) on purified hematopoietic progenitor cells (HPCs) induced in liquid suspension culture to unilineage differentiation/maturation through the erythroid (E), granulocytic (G), megakaryocytic (Mk), and monocytic (Mo) lineages. Reverse transcriptase-polymerase chain reaction (RT-PCR) and cytofluorimetric analysis showed the presence of both CXCR4 and CCR5 in quiescent HPCs, but failed to detect CCR3-specific transcripts. Chemokine expression in HPC progenies showed that CXCR4 receptor is detected on the majority of MKs from early to late stages of maturation, whereas it is moderately decreased in the Mo lineage. In the G pathway, two distinct cell populations, CXCR4+ and CXCR4−, were observed: morphological analysis of the sorted populations showed that the CXCR4+ cells were largely eosinophils and the CXCR4− were granulocytes of the neutrophilic series. Furthermore, in the E pathway, CXCR4 was almost completely absent. CCR5 expression is restricted to Mo cultures, ie, ≈30% to 80% cells throughout all monocytopoietic differentiation/maturation stages. Finally, CCR3 mRNA is always absent in all the unilineage cultures. Evaluation of CD4 expression by flow cytometry on both quiescent HPCs and differentiating unilineage precursors showed that the CD4 receptor is present on ≈15% of the starting CD34+ HPC population, highly expressed in the Mo lineage up to 80% at terminal maturation, present on 20% to 30% of maturing Mks, and not detectable in either the E or G lineage. Expression of CD4 receptor together with CXCR4 and/or CCR5 coreceptor in the four lineages correlates with hematopoietic precursor susceptibility to T-lymphotropic and macrophage (M)-tropic HIV strains infection: (1) CD4− G and E cells were resistant to both M-tropic and T-lymphotropic strains; (2) HPC-derived Mks were susceptible to T-tropic, but resistant to M-tropic, infection; (3) Mo differentiating cells efficiently replicate both HIV strains. Furthermore, we showed that the CXCR4 and CCR5 ligands (stromal-derived factor 1 and macrophage-inflammatory protein-1α MIP-1α, MIP-1β and RANTES, respectively) inhibit HIV replication in both maturing Mo and Mk cells. Taken together, our data show a lineage-specific modulation of chemokine receptor/coreceptor during hematopoietic cell differentiation and extend previous observations on the relationship between the expression of HIV receptor/coreceptors, susceptibility, and chemokine-mediated resistance to HIV infection.
Zirconia coatings were obtained with the spray pyrolysis process, using a precursor solution of zirconium
n-propoxide in 1-propanol. An investigation was undertaken into the influence of carrier gas ...(air, He, N
2 and Ar), temperature (450 and 600 °C), time (1 and 2 h) and substrate composition (borosilicate glass, alumina, stainless steel and carbon steel) on coating characteristics. The most important deposition parameters were found to be the atomic or molecular weight of the carrier gas and the pyrolysis temperature. Cubic ZrO
2 thin films, with dense and homogeneous nanostructrure were obtained using He and N
2 as carrier gas, at 600 °C, on ceramic substrates.
Electroless nickel-boron coatings on metal carbides Di Giampaolo, A.R.; Ordoñez, J.G.; Gugliemacci, J.M. ...
Surface & coatings technology,
02/1997, Letnik:
89, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Electroless deposition is a very simple process which can be used to obtain amorphous metallic coatings of uniform thickness on metallic or non-metallic substrates. In this work, nickel-boron ...coatings were deposited by electroless plating on WC and VC powders and sintered substrates. Two electrolyte solutions for the deposition of Ni-B coatings were developed: an alkaline and an acidic bath, both based on nickel chloride.
Coating characterization was carried out by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Auger electron spectroscopy (AES) and X-ray diffraction (XRD).
Both electrolytes produced continuous firms of uniform thickness on sintered carbide substrates; the acidic bath showed a higher deposition rate. Furthermore on the carbide powders it produced crack-free Ni-B continuous coatings. Ni was detected by EDS and the coating purity was confirmed by AES. XRD proved that amorphous coatings were obtained in all cases.
Summary
Haemophilia A (HA) patients with high responding inhibitors require therapies with bypassing agents to control bleedings or Immune Tolerance Induction (ITI) to attempt inhibitor eradication ...and restore FVIII therapy. The aim of this study was to assess the therapeutic management and product consumption of HA inhibitor patients and the relative costs in Italy. A retrospective survey was performed utilizing data from the National Registry of Congenital Coagulopathies and from a specific questionnaire on product consumption of HA inhibitor patients over the year 2011. Among HA patients, 10% had currently detectable inhibitors; 24% of patients were undergoing ITI (mostly children) and 76% utilized bypassing agents. Patients on ITI consumed 45 000 000 IU of FVIII (median consumption/patient of 1 200 000 IU year−1). Patients receiving bypassing agents utilized 21 000 000 IU of aPCC (median consumption/patient of 360 000 IU year−1), and 38 000 mg of rFVIIa (median consumption/patient of 440 mg year−1). The annual cost/patient on ITI and on bypassing agents therapy was analysed. Recombinant products represen‐ted the product of choice for children therapies in >90% of the cases. FVIII prophylaxis of severe HA patients without inhibitor costs about half than therapy with bypassing agents and is three times less expensive than prophylaxis with such agents. Therefore, the possibility to restore FVIII prophylaxis, having eradicated the inhibitor through ITI, can justify the high costs of ITI treatment needed in the short term. Consistent with this notion, over the last years a 50% increase in the number of patients undergoing ITI in Italy was registered.
Carbon steel substrates (AISI-1010) were surface treated with zinc phosphate prior to depositing sol-gel aluminosilicate coatings using three different deposition techniques: dipping, sol-spraying, ...and xerogel thermal spray with flame torch. Optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to characterize the sol-gel coatings; mechanical adherence was evaluated by mechanical indentation. The air oxidation resistance of the coatings at 600 °C was measured following the weight change. Corrosion resistance in H
2SO
4 was determined using the potentiodynamic method. The zinc phosphate interlayer was found to be adherent to the aluminosilicate coatings, enhancing their oxidation resistance and corrosion resistance.
Abstract
Aria is a plant hosting a
$${350}\,\hbox {m}$$
350
m
cryogenic isotopic distillation column, the tallest ever built, which is being installed in a mine shaft at Carbosulcis S.p.A., ...Nuraxi-Figus (SU), Italy. Aria is one of the pillars of the argon dark-matter search experimental program, lead by the Global Argon Dark Matter Collaboration. It was designed to reduce the isotopic abundance of
$${^{39}\hbox {Ar}}$$
39
Ar
in argon extracted from underground sources, called Underground Argon (UAr), which is used for dark-matter searches. Indeed,
$${^{39}\hbox {Ar}}$$
39
Ar
is a
$$\beta $$
β
-emitter of cosmogenic origin, whose activity poses background and pile-up concerns in the detectors. In this paper, we discuss the requirements, design, construction, tests, and projected performance of the plant for the isotopic cryogenic distillation of argon. We also present the successful results of the isotopic cryogenic distillation of nitrogen with a prototype plant.
Composite precursor powders for liquid phase sintering were obtained by coating WC and VC particles. The Ni–B coating was deposited onto the carbide nucleus by electroless processes in alkaline and ...acid bath, both based on nickel chloride. In order to observe structural modifications, the composite powders were heated in an argon atmosphere, during 5
min, at different temperatures in the range 400–1200°C. When heating, Ni and Ni
3B phases progressively formed within the amorphous Ni–B layer; then, Ni was retained as a unique crystalline phase. Sintering was performed in a temperature range of 1035–1200°C where a eutectic liquid phase is expected in the Ni–B system. The wetting behavior of the molten coating depended on the characteristics of the carbide skeleton. Thus, the segregation of the matrix toward the outer surfaces occurred when sintering VC and it adversely affected densification. In the case of WC sinters, the same effect was found at relatively high temperatures (1150–1200°C) while at lower temperatures (1035–1100°C) the metal matrix was uniformly distributed and the densification degree were between 91 and 93%.
B7 is a costimulatory molecule which is expressed on antigen-presenting cells and which plays a pivotal role in T cell activation and proliferation. To elucidate mechanisms regulating intracerebral ...immune responses, expression of B7 was examined in cultured microglial cells and in brain tissue from control and multiple sclerosis patients. Using immunocytochemical and polymerase chain reaction techniques, we show that B7 was expressed in cultured microglial cells from the human embryonic brain. Microglia also bound the soluble form of the B7 receptor CTLA-4 (CTLA-4-Ig). B7 gene expression and binding of anti-B7 antibodies and CTLA-4-Ig increased after treatment with interferon-gamma. B7 was not inducible in human astrocytes. Human microglia expressed other costimulatory molecules, such as intercellular adhesion molecule-1, LFA-1 and LFA-3. In sections of multiple sclerosis brains, B7 immunoreactivity was detected on activated microglia and infiltrating macrophages within active lesions. In chronic lesions, only perivascular cells were stained. B7 immunoreactivity was undetectable in sections from Alzheimer's disease or normal brain tissue. These data suggest that B7 may be involved in T cell activation and lesion development in multiple sclerosis and that the regulated expression of B7 on microglia may contribute to the local stimulation of T cell proliferation and effector functions.
We report the molecular analysis of an 8;14 reciprocal chromosome translocation in a case of acute lymphocytic leukemia (L3type). DNA from primary leukemic cells was analyzed on the basis of ...restriction endonuclease mapping by hybridization with various human c-myc and Ig heavy chain probes. The breakpoint of the translocation is within an ≈ 200-base-pair region in the first intron of the c-myc gene. The first, untranslated exon thereby remains on chromosome 8q-, whereas the whole protein-coding region is rearranged in the Cα1 locus on chromosome 14q+. RNA transfer blot analysis showed high levels of at least two different c-myc transcripts originated from the translocated gene. Both differ in size from the normal 2.2- and 2.4-kilobase transcripts. Both c-myc structure and expression were apparently normalized in remission phase. These studies demonstrate rearrangement and abnormal expression of c-myc in primary cells from an acute leukemia patient, thus adding to the concept of a key role for c-onc in human oncogenesis.
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