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The method for separation and quantitative determination of the main carotenoids in food by high-performance liquid chromatography (HPLC) was in-house validated. Tomato (Lycopersicon esculentum M.) as food matrix was used to demonstrate its linearity, repeatability, intermediate precision, detection and quantification limits, sensitivity and bias. In addition, stability of carotenoids was studied in function of temperature and time. Method accuracy was quantified through measurement uncertainties estimate based on this validation study. Furthermore, a study was conducted to evaluate variability coming from location in an experimental field composed by 12 subfields. The use of two metal free reverse phase columns and an organic mobile phase based on acetonitrile, methanol and dichloromethane enabled the separation of the six target comp...
Microcystin-LR (MCLR) is a peptide produced by freshwater cyanobacteria that induces severe hepatotoxicity in humans and animals. MCLR is also a potent tumour promoter and it has been proposed that this activity is mediated by the inhibition of protein phosphatases PP1/PP2A, possibly through the activation of proto-oncogenes c-jun, c-fos and c-myc. However, the mechanisms underlying MCLR-induced tumour promotion are still largely unknown, particularly in non-liver cells. In previous studies we have demonstrated that micromolar concentrations of MCLR induce cytotoxic effects in the kidney Vero-E6 cell line. The purpose of the present work was to evaluate whether the exposure to subcytotoxic concentrations of MCLR was sufficient to induce the proliferation of Vero-E6 cells. Through BrdU incorporation assay we show that at nanomolar conce...
Background: High iron concentrations have been reported in oligodendrocytes, myelin and macrophages in multiple sclerosis (MS) lesions. It has been proposed that HFE gene polymorphisms could have a role in MS. Methods: The C282Y and H63D HFE variants frequencies were determined in 373 patients with MS and compared with a normal population. Results: No significant association was found between HFE polymorphisms and disease susceptibility. An analysis of the association of genotypes with disease severity was performed, and the C282Y allele was more frequent in the aggressive group. Conclusions: Patients carrying the C282Y variant seem to have a worse prognosis.
Globin genes, which encode the protein subunits of hemoglobin (Hb), are organized in two different gene clusters and present a coordinated and differential pattern of expression during development. Concerning the human α-globin gene cluster (located at chromosome region 16p13.3), four upstream highly conserved elements known as multispecies conserved sequences (MCS-R1-4) or DNase I hypersensitive sites (HSs) are implicated in the long-range regulation of downstream gene expression. However, only the absence of the MCS-R2 site (HS-40) has proven to drastically downregulate the expression of those genes, and consequently, it has been regarded as the major and crucial distal regulatory element. In this study, Multiplex Ligation-dependent Probe Amplification was used to screen for deletions in the telomeric region of the short arm of chrom...
Information on distribution and relative abundance of the mosquito fauna of mainland Portugal has been collected by several surveillance programmes and projects over a long period. The work presented here documents additional information provided by capture of adult mosquitoes by the use of CDC light traps baited with CO2 in 48 localities in 13 districts in different parts of mainland Portugal during the period 2005-2008, and by larval surveys using dippers. More than 150,000 adult mosquitoes and 3,000 larvae belonging to 16 species were identified at the National Institute of Health / Centre for Vectors and Infectious Diseases Research. The three commonest species were Ochlerotatus caspius, Culex pipiens, and Cx. theileri. The most widespread species was Cx. pipiens, followed by Culiseta longiareolata. The composition and abundance of...
OBJECTIVES: Replication of GWAS association findings remains the gold standard for results validation. Our aim was to test the association of four polymorphisms (rs1671021 in LLGL2, rs753307 in RUVBL2, rs6007897 and rs4044210 in CELSR1) previously identified as ischemic stroke (IS) risk factors in a phased GWAS performed on 6341 Japanese individuals [1]. METHODS: These polymorphisms were genotyped in a Portuguese sample of 566 IS cases and 525 controls, and their allele, genotype and haplotype associations were assessed. RESULTS: rs6007897 and rs4044210 in CELSR1 were associated with stroke risk individually (OR[95%CI]=1.43[1.13-1.81], p=0.003 and 1.38[1.09-1.74], p=0.007, respectively), and in combination as a haplotype. These associations remain after correction for multiple testing and in a meta-analysis with the original findings...
A research project on antiviral drug resistance of influenza viruses circulating in Portugal has been carried out since 2007. Here, the first results obtained regarding the evaluation of susceptibility to amantadine and oseltamivir are presented. Information about antiviral prescription and exposure was available through the National Influenza Surveillance Programme. Amantadine susceptibility was evaluated by pyrosequencing for known resistance markers on 178 influenza A strains from 2004/2005 to 2006/2007. Susceptibility to oseltamivir was evaluated by 50% inhibitory concentration determination on 340 virus strains from 2004/2005 to 2008/2009, 134 of which were further analyzed by sequencing of the neuraminidase gene. This study revealed that influenza antiviral drugs were rarely prescribed at national level. Resistance to amantadine ...
Poly (ADP-ribose) polymerase-1 (Parp1) has been implicated in DNA base excision repair, single- and double-strand break repair pathways, as well as in cell death by apoptosis or necrosis. We used Parp1(-/-) lacZ plasmid-based transgenic mice to investigate whether Parp1 deficiency influences the in vivo mutagenic and clastogenic response to the alkylating agent N-ethyl-N-Nitrosourea (ENU) in somatic and germ-cell tissues. The comparison of the lacZ mutant frequencies (MFs) between Parp1(+/+) and Parp1(-/-) mice showed that the ablation of Parp1 does not affect the spontaneous or ENU-induced MFs in liver and testis. In addition, the spectrum of the ENU-induced mutations was not dependent on the Parp1 status, given that similar spectra, consisting mostly of point mutations and a small fraction of deletions/insertions, wereobserved in org...
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