519 research outputs found

    Treatment of malignant gliomas with a replicating adenoviral vector expressing herpes simplex virus-thymidine kinase

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    We evaluated the interaction between oncolytic, replication-competent adenoviral vectors and the herpes simplex virus-1 thymidine kinase (HSV1-tk) gene/ganciclovir (GCV) suicide system for the treatment of malignant gliomas. We constructed a panel of replication-competent adenoviral vectors in which the luciferase (IG.Ad5E1(+). E3Luc) or HSV1-tk gene (IG.Ad5E1(+).E3TK) replace the M(r) 19,000 glycoprotein (gp19K) coding sequence in the E3 region. IG.Ad5E1. IG.Ad5.ClipLuc and IG.AdApt.TK are E1-deleted viruses that contain the luciferase or the HSV1-tk gene in the former E1 region driven by the human cytomegalovirus promoter. IG.Ad5.Sarcoma 1800HSA.E3Luc contains an irrelevant gene in the E1 region, whereas the gp19K coding sequence in the E3 region is replaced by the luciferase gene as in the replicating virus IG.Ad5E1(+).E3Luc. For in vitro experiments, we used a panel of human glioma cell lines (U87 MG, T98G, A172, LW5, and U251), a rat gliosarcoma cell line (9 L), and human lung (A549) and prostate carcinoma (P3) cell lines. In vitro, GCV sensitivity (10 microg/ml) was studied in U87 MG cells after infection at a multiplicity of infection of 1 and 10. A s.c. U87 MG glioma xenograft model was established in NIH-bg-nu-xid mice. Tumors of 100-150 mm(3) were treated with a single injection of adenovirus 10(9) IU suspended in 100 microl of PBS, and GCV 100 mg/kg was administered i.p. twice daily for 7 days. The cytopathic effect of all three replication-competent adenoviral vectors was similar to the cytopathic effect of wild-type adenovirus 5 on all human cell lines tested, indicating that deletion of the E3 gp19K sequences did not affect the oncolytic effect of the vectors. In vitro, luciferase expression was the same for both E1-deleted vectors (IG.Ad5.ClipLuc and IG.Ad5.Sarcoma 1800HSA.E3Luc), demonstrating the strength of the internal E3 promoter even in the absence of E1A. However, in vitro expression levels obtained with replication-competent IG.Ad5E1(+). E3Luc were 3 log higher (allowing infection with a

    In vitro and in vivo gene transfer to pulmonary cells mediated by cationic liposomes

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    Cationic liposomes have been proposed as alternative to adenovirus in the treatment of cystic fibrosis lung disease. Therefore, we have investigated the efficiency of two lipid mixtures in mediating gene transfer in in vitro and in vivo models. The cationic lipid DOTMA (N-(1-(2,3(dioleyloxy)propyl)-n,n,n-trimethylammoniumchloride) and DOGS (dioctadecylamidoglycylspermine) were used in combination with the neutral lipid DOPE (dioleoylphosphatidylethanolamine). The relative transfection efficiencies of the two cationic liposomes were tested using the bacterial ÎČ-galactosidase (lacZ) and the firefly luciferase genes. Gene expression was detected in both cell lines and primary culture of rhesus monkey airway epithelium after transfection with plasmid DNA complexed with DOGS/DOPE or DOTMA/DOPE. Transfection efficiency of both types of lipids was higher in the mouse fibroblast 3T3 cell line as compared to human carcinoma A549 cells and primary epithelial cultures. Administration of DNA-liposome complexes via intratracheal instillation resulted in expression of the lacZ and luciferase marker gene in the mouse airways. In vivo transfection mediated by both types of liposomes were proven to be far less efficient than adenovirus treatment

    Atomic carbon at redshift ~2.5

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    Using the IRAM 30m telescope we detected the lower fine structure line of neutral carbon towards three high--redshift sources: IRAS FSC10214 (z=2.3), SMMJ14011+0252 (z=2.5) and H1413+117 (Cloverleaf quasar, z=2.5). SMMJ14011+0252 is the first high--redshift, non--AGN source in which CI has been detected. The CI(1-0) line from FSC10214 is almost an order of magnitude weaker than previously claimed, while our detection in the Cloverleaf is in good agreement with earlier observations. The CI(1-0) linewidths are similar to the CO widths, indicating that both lines trace similar regions of molecular gas on galactic scales. Derived CI masses for all three objects are of order few 10^7 solar masses and the implied CI(1-0)/CO(3-2) line luminosity ratio is about 0.2. This number is similar to values found in local galaxies. We derive a CI abundance of 5x10^{-5} which implies significant metal enrichment of the cold molecular gas at redshifts 2.5 (age of the universe 2.7 Gyr). We conclude that the physical properties of systems at large lookback times are similar to today's starburst/AGN environments.Comment: 4 pages, 2 figures; accepted by A&

    The essential signature of a massive starburst in a distant galaxy

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    Observations of carbon monoxide (CO) emission in high redshift (z>2) galaxies indicate the presence of large amounts of molecular gas. Many of these galaxies contain an active galactic nucleus (AGN) powered by accretion of gas onto a supermassive black hole, and a key question is whether their extremely high infrared luminosities result from the AGN, or from bursts of massive star formation (associated with the molecular gas), or both. In the Milky Way, high-mass stars form in the dense cores of interstellar molecular clouds; gas densities are n(H2)>105 cm-3 in the cores. Recent surveys show that virtually all galactic sites of high-mass star formation have similarly high densities. The bulk of the cloud material traced by CO observations is at a much lower density. In galaxies in the local Universe, the HCN(J=1-0) line is an effective tracer of the high-density molecular gas. Here we report observations of HCN emission in the early Universe from the infrared luminous 'Cloverleaf' quasar (at a redshift z=2.5579). The HCN line luminosity indicates the presence of 10 billion solar masses of very dense gas, an essential feature of an immense starburst that contributes, together with the AGN it harbors, to its high infrared luminosity.Comment: PDF pape

    New constraints on elemental and Pb and Nd isotope compositions of South American and Southern African aerosol sources to the South Atlantic Ocean

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    Improving the geochemical database available for characterising potential natural and anthropogenic aerosol sources from South America and Southern Africa is a critical precondition for studies aimed at understanding trace metal controls on the marine biogeochemical cycles of the South Atlantic Ocean. We here present new elemental and isotopic data for a wide range of sample types from South America and Southern Africa that are potentially important aerosol sources. This includes road dust from Buenos Aires and lichen samples from Johannesburg, soil dust from Patagonia, volcanic ash from the Andean volcanic belt, and aerosol samples from SĂŁo Paulo. All samples were investigated for major (Al, Ca, Fe, Mg, Na, K, Mn) and trace element (Cd, Co, Cr, Cu, Ni, Pb, REE, Sc, Th, Y, V, Zn) concentrations and Nd and Pb isotopic compositions. We show that diagrams of 208Pb/207Pb vs. ΔNd, 208Pb/207Pb vs. Pb/Al, 1/[Pb], Zn/Al, Cd/Al, Cu/Al, and ΔNd vs. Pb/Al, and 1/[Nd] are best suited to separate South American and South African source regions as well as natural and anthropogenic sources. A subset of samples from Patagonia and the Andes was additionally subjected to separation of a fine (<5â€ŻÎŒm) fraction and compared to the composition of the bulk sample. We show that differences in the geochemical signature of bulk samples between individual regions and source types are significantly larger than between grain sizes. Jointly, these findings present an important step forward towards a quantitative assessment of aeolian trace metal inputs to the South Atlantic Ocean

    The origin of the 1500-year climate cycles in Holocene North-Atlantic records

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    © 2007 Author(s) et al. This is an open-access article distributed under a Creative Commons License. The definitive version was published in Climate of the Past 3 (2007): 569-575, doi:10.5194/cp-3-569-2007Since the first suggestion of 1500-year cycles in the advance and retreat of glaciers (Denton and Karlen, 1973), many studies have uncovered evidence of repeated climate oscillations of 2500, 1500, and 1000 years. During last glacial period, natural climate cycles of 1500 years appear to be persistent (Bond and Lotti, 1995) and remarkably regular (Mayewski et al., 1997; Rahmstorf, 2003), yet the origin of this pacing during the Holocene remains a mystery (Rahmstorf, 2003), making it one of the outstanding puzzles of climate variability. Solar variability is often considered likely to be responsible for such cyclicities, but the evidence for solar forcing is difficult to evaluate within available data series due to the shortcomings of conventional time-series analyses. However, the wavelets analysis method is appropriate when considering non-stationary variability. Here we show by the use of wavelets analysis that it is possible to distinguish solar forcing of 1000- and 2500- year oscillations from oceanic forcing of 1500-year cycles. Using this method, the relative contribution of solar-related and ocean-related climate influences can be distinguished throughout the 10 000 yr Holocene intervals since the last ice age. These results reveal that the 1500-year climate cycles are linked with the oceanic circulation and not with variations in solar output as previously argued (Bond et al., 2001). In this light, previously studied marine sediment (Bianchi and McCave, 1999; Chapman and Shackleton, 2000; Giraudeau et al., 2000), ice core (O'Brien et al., 1995; Vonmoos et al., 2006) and dust records (Jackson et al., 2005) can be seen to contain the evidence of combined forcing mechanisms, whose relative influences varied during the course of the Holocene. Circum-Atlantic climate records cannot be explained exclusively by solar forcing, but require changes in ocean circulation, as suggested previously (Broecker et al., 2001; McManus et al., 1999).This work is supported by ANR project: “Integration des contraintes Paleoclimatiques pour reduire les Incertitudes sur l’evolution du Climat pendant les periodes Chaudes”- PICC (ANR-05-BLAN- 0312-02)

    The Evolution of Interstellar Medium Mass Probed by Dust Emission: ALMA Observations at z = 0.3-2

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    The use of submillimeter dust continuum emission to probe the mass of interstellar dust and gas in galaxies is empirically calibrated using samples of local star-forming galaxies, Planck observations of the Milky Way, and high-redshift submillimeter galaxies. All of these objects suggest a similar calibration, strongly supporting the view that the Rayleigh-Jeans tail of the dust emission can be used as an accurate and very fast probe of the interstellar medium (ISM) in galaxies. We present ALMA Cycle 0 observations of the Band 7 (350 GHz) dust emission in 107 galaxies from z = 0.2 to 2.5. Three samples of galaxies with a total of 101 galaxies were stellar-mass-selected from COSMOS to have M* ≃ 10^(11) M☉: 37 at z ~ 0.4, 33 at z ~ 0.9, and 31 at z = 2. A fourth sample with six infrared-luminous galaxies at z = 2 was observed for comparison with the purely mass-selected samples. From the fluxes detected in the stacked images for each sample, we find that the ISM content has decreased by a factor ~6 from 1 to 2 × 10^(10) M☉ at both z = 2 and 0.9 down to ~2 × 10^9 M☉ at z = 0.4. The infrared-luminous sample at z = 2 shows a further ~4 times increase in M_(ISM) compared with the equivalent non-infrared-bright sample at the same redshift. The gas mass fractions are ~2% ± 0.5%, 12% ± 3%, 14% ± 2%, and 53% ± 3% for the four subsamples (z = 0.4, 0.9, and 2 and infrared-bright galaxies)

    Isolated limb perfusion for local gene delivery: efficient and targeted adenovirus-mediated gene transfer into soft tissue sarcomas

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    OBJECTIVE: To evaluate the potential of isolated limb perfusion (ILP) for efficient and tumor-specific adenovirus-mediated gene transfer in sarcoma-bearing rats. SUMMARY BACKGROUND DATA: A major concern in adenovirus-mediated gene therapy in cancer is the transfer of genes to organs other than the tumor, especially organs with a rapid cell turnover. Adjustment of the vector delivery route might be an option creating tumor specificity in therapeutic gene expression. METHODS: Rat hind limb sarcomas (5-10 mm) were transfected with recombinant adenoviruses. Intratumoral luciferase expression after ILP was compared with systemic administration, regional infusion, or intratumoral injection using a similar dose of adenoviruses carrying the luciferase marker gene. Localization studies using lacZ as a marker gene were performed to evaluate the intratumoral distribution of transfected cells after both ILP and intratumoral injection. RESULTS: Intratumoral luciferase activity after ILP or intratumoral administration was significantly higher compared with regional infusion or systemic administration. After ILP, luciferase gene expression was minimal in extratumoral organs, whether outside or inside the isolated circuit. Localization studies demonstrated that transfection was confined to tumor cells lying along the needle track after intratumoral injection, whereas after ILP, lacZ expression was found in viable tumor cells and in the tumor-associated vasculature. CONCLUSIONS: Using ILP, efficient and tumor-specific gene transfection can be achieved. The ILP technique might be useful for the delivery of recombinant adenoviruses carrying therapeutic gene constructs to enhance tumor control

    Single metallic nanoparticle imaging for protein detection in cells

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    We performed a visualization of membrane proteins labeled with 10-nm gold nanoparticles in cells, using an all-optical method based on photothermal interference contrast. The high sensitivity of the method and the stability of the signals allows 3D imaging of individual nanoparticles without the drawbacks of photobleaching and blinking inherent to fluorescent markers. A simple analytical model is derived to account for the measurements of the signal amplitude and the spatial resolution. The photothermal interference contrast method provides an efficient, reproducible, and promising way to visualize low amounts of proteins in cells by optical means
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