773 research outputs found
Metals in Feathers of African Penguins (Spheniscus demersus): Considerations for the Welfare and Management of Seabirds Under Human Care
Development, validation and application to real samples of amultiresidue LC-MS/MS method for determination of β2-agonists and anabolic steroids in bovine hair
Pacman percolation: a model for enzyme gel degradation
We study a model for the gel degradation by an enzyme, where the gel is
schematized as a cubic lattice, and the enzyme as a random walker, that cuts
the bonds over which it passes. The model undergoes a (reverse) percolation
transition, which for low density of enzymes falls in a universality class
different from random percolation. In particular we have measured a gel
fraction critical exponent beta=1.0+-0.1, in excellent agreement with
experiments made on the real system.Comment: 4 pages, 7 eps figure
Modulation of cholesterol homeostasis by antiproliferative drugs in human pterygium fibroblasts.
PURPOSE. The authors have previously shown that the growth of cultured fibroblasts obtained from primary pterygia was associated with an increase in cholesterol esterification, suggesting that alterations of cholesterol homeostasis may be involved in the development and progression of this disorder. This investigation was conducted to determine whether antiproliferative agents such as pioglitazone (PIO) and everolimus (EVE) may inhibit proteins involved in the cholesterol ester cycle and the proliferation of pterygium fibroblasts (PF). METHODS. Quiescent normal conjunctival fibroblasts and PFs were treated with or without inhibitors of cell proliferation (PIO and EVE) or with inhibitors of cholesterol esterification— progesterone (Pg) and Sandoz compound (SaH)—and then were stimulated to growth by 10% fetal calf serum (FCS). Cell proliferation was assessed by counting cells. Trypan blue uptake was used to determine cell viability. mRNA and protein levels were determined by reverse transcription‐polymerase chain reaction (RT-PCR) and Western blot analysis, respectively. RESULTS. PIO and EVE significantly abolished the increase in cholesterol esters, acyl-coenzyme A cholesterol acyltransferase (ACAT1), and multidrug resistance protein (MDR1) mRNA observed in growing cells. Each inhibitor upregulated ATP-binding cassette-A1 (ABCA1), neutral cholesterol ester hydrolase (NCEH) mRNA, and caveolin-1 expression in a manner similar to that of specific inhibitors of cholesterol esterification such as Pg and SaH. CONCLUSIONS. Intracellular modifications of cholesterol homeostasis may be relevant to pterygium development. Moreover, antiproliferative agents such as PIO and EVE may represent a potential topical medication in the prevention and inhibition of pterygium growth at an early stage, probably by modulation of cholesterol ester metabolism. (Invest Ophthalmol Vis Sci. 2007;48:3450‐3458) DOI:10.1167/iovs.06-105
First Insights Into Trace Element Accumulation by Philoscia affinis (Crustacea, Isopoda): a Novel Tracer to Assess Soil Contamination in Lowland Plains?
Isopods are terrestrial invertebrates that accumulate trace elements in large quantities, thus providing information on levels of soil
contamination. However, the accumulation pattern seems to be species dependent. For this study, specimens of Philoscia affinis
(Isopoda, Oniscidea) and soil samples were collected from both a protected area (site 1) and urban roadside (site 2) in the low
plain of Friuli-Venezia Giulia (northeast Italy) to determine whether P. affinis could serve as a potential candidate for monitoring
soil contamination. To do this, the following objectives were achieved: a) the level of trace elements (Al, Cd, Cu, Fe, Hg, Mn, Pb,
Zn) were detected in soils and isopods; 2) the difference in trace elements accumulation was compared in the two sampling sites;
3) the bioaccumulation factor (BAF) was calculated for each element. With some exceptions, trace element concentrations were
higher in both isopods and soil samples from the urban roadside compared to the protected area. Furthermore, except for Cd, Cu,
and Zn, trace element levels were higher in the soil than in the isopod samples. The higher mean BAF values were recorded for
Cd (6.169 and 6.974 for site 1 and 2, respectively), Cu (10.324 and 11.452 for site 1 and 2, respectively), and Zn (1.836 and 2:
1.943 for site 1 and 2, respectively), whereas BAF values <1 were recorded for the other elements. Philoscia affinis was found to
be a potential candidate to monitor soil contamination as a macro-concentrator of Cu and Cd and a micro-concentrator of Zn
Zooplankton from a North Western Mediterranean area as a model of metal transfer in a marine environment
Oxidative stress related to chlorpyrifos exposure in rainbow trout: Acute and medium term effects on genetic biomarkers
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