Comparison of Short-Term Estrogenicity Tests for Identification of Hormone-Disrupting Chemicals

The aim of this study was to compare results obtained by eight different short-term assays of estrogenlike actions of chemicals conducted in 10 different laboratories in five countries. Twenty chemicals were selected to represent direct-acting estrogens, compounds with estrogenic metabolites, estrogenic antagonists, and a known cytotoxic agent. Also included in the test panel were 17β-estradiol as a positive control and ethanol as solvent control. The test compounds were coded before distribution. Test methods included direct binding to the estrogen receptor (ER), proliferation of MCF-7 cells, transient reporter gene expression in MCF-7 cells, reporter gene expression in yeast strains stably transfected with the human ER and an estrogen-responsive reporter gene, and vitellogenin production in juvenile rainbow trout. 17β-Estradiol, 17α-ethynyl estradiol, and diethylstilbestrol induced a strong estrogenic response in all test systems. Colchicine caused cytotoxicity only. Bisphenol A induced an estrogenic response in all assays. The results obtained for the remaining test compounds—tamoxifen, ICI 182.780, testosterone, bisphenol A dimethacrylate, 4-n-octylphenol, 4-n-nonylphenol, nonylphenol dodecylethoxylate, butylbenzylphthalate, dibutylphthalate, methoxychlor, o,p′-DDT, p,p′-DDE, endosulfan, chlomequat chloride, and ethanol—varied among the assays. The results demonstrate that careful standardization is necessary to obtain a reasonable degree of reproducibility. Also, similar methods vary in their sensitivity to estrogenic compounds. Thus, short-term tests are useful for screening purposes, but the methods must be further validated by additional interlaboratory and interassay comparisons to document the reliability of the methods

The properties of field elliptical galaxies at intermediate redshift. II: photometry and spectroscopy of an HST selected sample

A sample of field early-type galaxies (E/S0) at intermediate redshift ($z\sim0.1-0.6$) is selected, based on morphology and colours from HST-WFPC2 parallel images. Photometric structural parameters (effective radius R_{\tx{e}} and effective surface brightness SB_{\tx{e}}) are derived through the F606W and F814W filters, using luminosity profile fitting and two-dimensional fitting techniques. The combined parameter that enters the Fundamental Plane (\log R_{\tx{e}}-\beta SB_{\tx{e}}, with $\beta\approx0.32$) is shown to suffer from significantly smaller uncertainties (r.m.s. 0.03) than the individual structural parameters (e.g. $\sim 15$ per cent r.m.s. on the effective radius). High signal-to-noise intermediate resolution spectra, taken at the ESO-3.6m, yield redshifts for 35 galaxies and central velocity dispersions for 22 galaxies. Central velocity dispersions are derived using a library of stellar templates covering a wide range of spectral types, in order to study the effects of templates mismatches. The average random error on the central velocity dispersion is found to be 8 per cent and the average systematic error due to template mismatch is found to be 5 per cent. The errors on velocity dispersion measurement and the effects of template mismatches are studied by means of extensive Montecarlo simulations. In addition, we investigate whether the determination of the velocity dispersion is sensitive to the spectral range used, finding that the value of velocity dispersion is unchanged when the spectral regions that include the absorption features Ca HK and NaD are masked out during the fit.Comment: 19 pages, 16 figures, MNRAS accepte

The red optical afterglow of GRB 030725

We present a photometric study of the optical counterpart of the long-duration Gamma Ray Burst (GRB) 030725, which triggered the HETE FREGATE and WXM instruments on July 25th, 2003, and lasted more than 160s. An optical counterpart was identified at the Bronberg Observatory in South Africa about 7 hours after the burst occurred. The optical afterglow (OA) was observed between 4 and 15 days after the burst with the 1.54m Danish telescope at La Silla in the V, Rc, and Ic bands. We fit a broken power law to the data and determine a break time in the light curve between 16 hours and 4.7 days after the first detection of the burst. The decay slope is alpha1 = -0.59 +0.59/-0.44 before and alpha2 = -1.43 +/- 0.06 after the break. A bump may be present in the light curve, only significant at the 2-sigma level, 13.9 days after the main burst. The spectral slope of the OA, measured 12 days after the burst, is -2.9 +/- 0.6 , i.e. it falls in the extreme red end of the distribution of previous OA spectral slopes. Observations of the field 8 months after the burst with the EMMI instrument on the NTT telescope (La Silla) resulted in an upper limit of Rc=24.7 mag for the host galaxy of GRB 030725. The OA of GRB 030725 was discovered at a private, non-professional observatory and we point out that with the current suite of gamma ray satellites, an effort to organize future contributions of amateur observers may provide substantial help in GRB light curve follow up efforts.Comment: Accepted for publication in A&A, 6 pages, 2 figure

The properties of field elliptical galaxies at intermediate redshift. III: the Fundamental Plane and the evolution of stellar populations from z~0.4 to z=0

We report on the study of a sample of 25 field early-type galaxies, in the redshift range z~0.1-0.5, selected on the basis of colours and morphology from the HST-MDS. Field early-type galaxies define a tight Fundamental Plane (FP) out to z~0.4, with scatter unchanged with respect to local samples, within the observational errors. The intermediate redshift FP is offset with respect to the FP of the Coma Cluster. The offset of the FP is found to increase with redshift. The evolution of the FP is studied quantitatively with a Bayesian-Montecarlo technique. By applying this technique, we find that the offset of the intercept of the FP (\Delta \gamma) with respect to the local FP increases as \Delta \gamma = \tau z with the following 68 per cent limits: 0.33<\tau<0.44 (for \Omega=1, \Omega_{\Lambda}=0) or 0.44<\tau<0.56 (for \Omega=0.3,\Omega_{\Lambda}=0.7). In addition, we interpret the results in terms of the evolution of the stellar populations, under the assumption of passive evolution. In a single-burst scenario, the observed properties are consistent with those of a stellar population formed at z>2 (for \Omega=1, \Omega_{\Lambda}=0, H_0=50 \kms Mpc^{-1}) or 0.8<z<1.6 (for \Omega=0.3, \Omega_{\Lambda}=0.7, H_0=65 \kms Mpc^{-1}). If a small fraction of the stellar mass is formed in a secondary burst, the primary burst may have occurred at higher z. Finally, the intercept and scatter of the FP found for field early-type galaxies and for cluster data at z~0.4 are mutually consistent, within the observational errors. If higher redshift (up to z=0.83) cluster data are considered, the ages of the stellar populations of field early-type galaxies inferred from a single-burst scenario are found to be marginally smaller than the ages derived for the cluster galaxies. [shortened]Comment: 19 pages, 23 figures, MNRAS, accepte

The research on the immuno-modulatory defect of Mesenchymal Stem Cell from Chronic Myeloid Leukemia patients

Overwhelming evidence from leukemia research has shown that the clonal population of neoplastic cells exhibits marked heterogeneity with respect to proliferation and differentiation. There are rare stem cells within the leukemic population that possess extensive proliferation and self-renewal capacity not found in the majority of the leukemic cells. These leukemic stem cells are necessary and sufficient to maintain the leukemia. While the hematopoietic stem cell (HSC) origin of CML was first suggested over 30 years ago, recently CML-initiating cells beyond HSCs are also being investigated. We have previously isolated fetal liver kinase-1-positive (Flk1+) cells carrying the BCR/ABL fusion gene from the bone marrow of Philadelphia chromosome-positive (Ph+) patients with hemangioblast property. Here, we showed that CML patient-derived Flk1+CD31-CD34-MSCs had normal morphology, phenotype and karyotype but appeared impaired in immuno-modulatory function. The capacity of patient Flk1+CD31-CD34- MSCs to inhibit T lymphocyte activation and proliferation was impaired in vitro. CML patient-derived MSCs have impaired immuno-modulatory functions, suggesting that the dysregulation of hematopoiesis and immune response may originate from MSCs rather than HSCs. MSCs might be a potential target for developing efficacious cures for CML