182 research outputs found
Soil hydraulic properties in different soil texture classes
Soil texture influences significantly soil hydraulic properties, which due to soil he-terogeneity normally present large spatial variability. The variability of soil reten-tion θ(h), and hydraulic conductivity K(h) curves, in 11 of the 12 texture classes of the diagram of Gomes e Silva (1962) was studied. For each textural class, average, maximum, minimum, and the standard deviation values for the Mualem van Ge-nuchten parameters are presented based on 558 θ(h) and 245 K(h) curves deter-mined in undisturbed soil samples which are included in the PROPSOLO database of Estação Agronómica Nacional. An av-erage function describing θ(h) and K(h) in each textural class is also presente
The cyclooxigenase-2 inhibitor parecoxib prevents epidermal dysplasia in HPV16-transgenic mice: efficacy and safety observations
Carcinogenesis induced by high-risk human papillomavirus (HPV) involves inflammatory
phenomena, partially mediated by cyclooxigenase-2. In pre-clinical models of HPV-induced cancer,
cyclooxygenase-2 inhibitors have shown significant e cacy, but also considerable toxicity. This study
addresses the chemopreventive e ect and hepatic toxicity of a specific cyclooxigensase-2 inhibitor,
parecoxib, in HPV16-transgenic mice. Forty-three 20 weeks-old female mice were divided into four
groups: I (HPV16+/-, n = 10, parecoxib-treated); II (HPV16+/- n = 11, untreated); III (HPV16+/-,
n = 11, parecoxib-treated) and IV (HPV16+/- n = 11, untreated). Parecoxib (5.0 mg/kg once daily)
or vehicle was administered intraperitoneally for 22 consecutive days. Skin lesions were classified
histologically. Toxicological endpoints included genotoxic parameters, hepatic oxidative stress,
transaminases and histology. Parecoxib completely prevented the onset of epidermal dysplasia in
HPV16+/- treated animals (0% versus 64% in HPV16+/- untreated, p = 0.027). Parecoxib decreases
lipid peroxidation (LPO) and superoxide dismutase (SOD) activity and increases the GSH:GSSG
ratio in HPV16+/- treated animals meaning that oxidative stress is lower. Parecoxib increased
genotoxic stress parameters in wild-type and HPV16-transgenic mice, but didn’t modify histological or biochemical hepatic parameters. These results indicate that parecoxib has chemopreventive e ects
against HPV16-induced lesions while maintaining an acceptable toxicological profile in this model.This work is supported by National Funds by FCT—Portuguese Foundation for Science and Technology,
under the projects UID/AGR/04033/2019, UID/CVT/00772/2019 and UID/EQU/00511/2019 - Laboratory for Process
Engineering, Environment, Biotechnology and Energy—LEPABE funded by national funds through FCT/MCTES
(PIDDAC); Project “LEPABE-2-ECO-INNOVATION”—NORTE-01-0145-FEDER-000005, funded by Norte Portugal
Regional Operational Programme (NORTE 2020), under PORTUGAL 2020 Partnership Agreement, through the
European Regional Development Fund.info:eu-repo/semantics/publishedVersio
Projeto RiskBenefit4EU - uma estratégia para a avaliação de risco-benefício de alimentos em Portugal
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