18 research outputs found

    In utero exposure to butyl benzyl phthalate induces modifications in the morphology and the gene expression profile of the mammary gland: an experimental study in rats

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    <p>Abstract</p> <p>Background</p> <p>Environmental estrogens are exogenous estrogen-mimicking compounds that can interfere with endogenous endocrine systems. Several of these endocrine disruptors have been shown to alter normal development and influence tumorigenesis in experimental models. N-butyl benzyl phthalate (BBP), a widely used plasticizer, is a well-known endocrine disruptor. The aim of this study was to elucidate the effect of prenatal exposure to BBP on the morphology, proliferative index, and genomic signature of the rat mammary gland at different ages.</p> <p>Methods</p> <p><it>In utero </it>exposure was performed by gavage of pregnant Sprague Dawley CD rats with 120mg or 500mg BBP/kg/day from day 10 post-conception to delivery. Female litters were euthanized at 21, 35, 50 and 100 days. The morphology and proliferative index of the mammary gland were studied from whole mount preparations and BrdU incorporation, respectively. Gene expression profile was assessed by microarrays. Several genes found differentially expressed and related to different functional categories were further validated by real time RT-PCR.</p> <p>Results</p> <p>Prenatal exposure of BBP induced delayed vaginal opening and changes in the post-natal mammary gland long after the end of the treatment, mainly by 35 days of age. Exposure to the high dose resulted in modifications in architecture and proliferative index of the mammary gland, mostly affecting the undifferentiated terminal end buds. Moreover, the expression profiles of this gland in the exposed rats were modified in a dose-dependent fashion. Analysis of functional categories showed that modified genes were related to immune function, cell signaling, proliferation and differentiation, or metabolism.</p> <p>Conclusions</p> <p>Our data suggest that <it>in utero </it>exposure to BBP induced a delayed pubertal onset and modified morphology of the mammary gland. These alterations were accompanied by modifications in gene expression previously associated with an increased susceptibility to carcinogenesis.</p

    Failure analysis by indentation test of electrodeposited nanocrystalline CO-W and Fe-W thin films

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    The aim of this paper is to study the failure of the electrodeposited Co-W and Fe-W alloys onto copper and steel substrates by the indentation technique, examine plastic strain distributions around indentations and evaluate behaviour of the system "coating-substrate". The alloys of Co-W and Fe-W obtained electrodeposited from citrate-ammonia baths are nanocrystalline. The values of grain size were evaluated based on the XRD spectrum and show values 30-37 Å. An experimental investigation into the Vickers indentation hardness and associated plastic deformation in electrochemically performed coatings was conducted. The methodology applied for this study allows obtaining the qualitative data to describe the behaviour of the system "coating-substrate", when both are deforming plastically. Implications of this study in understanding the mechanical behaviour of coatings and their derivatives are discussed.status: publishe
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