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Browsing by Author "Aguiar, A."

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  • 2011-11Conference object Unknown Show more
  • A familial partial AZFb-c microdeletion associated with diferente fértile phenotypes
    Publication . Pereira, I.; Aguiar, A.; Correia, S.; Pinto, M.G.; Calhaz Jorge, C.; Gonçalves, J.
    After the Klinefelter syndrome, Y chromosome microdeletions are the second most frequent genetic cause of spermatogenic failure resulting in male infertility. Y chromosome microdeletions, encompassing one or more of the three AZF regions, are associated with diverse testicular histology, ranging from Sertoli-cell-only syndrome (AZFa del), maturation arrest (AZFb del) to hypospermatogenesis (AZFc del). The molecular screening of these regions is routinely performed in the work-up of infertile patients with azoospermia or severe oligozoospermia as each one has different prognostic values, both in terms of clinical decision-making and appropriate genetic counselling as well as for understanding the etiology of spermatogenesis impairment. Different partial AZFc deletions were already described, although it is still controversial if these are truly a genetic risk factor for spermatogenesis impairment or a deletional variant without phenotypic consequences. Here we present the molecular results obtained after AZF analysis of two infertile brothers (both diagnosed with oligoteratoastenozoospermia), and of their fertile father. Several multiplex-PCR assays were performed with distinct sets of STS markers, specific for the three AZF regions. The molecular analysis revealed that all three men presented the same partial AZFb/c microdeletion, namely the absence of the sY1197, sY1291 and sY1192 STSs. This microdeletion probably results from the recombination of amplicons b1/b3, reducing the gene copy number of PRY, BPY, DAZ, and RBMY. The b1/b3 deletion is rare and its influence on spermatogenesis is still not clear since it can be found in men with severe oligozoospermia or with normal sperm counts. Our result suggests that b1/b3 del is most likely a risk factor predisposing to spermatogenic failure, but is not sufficient alone. The different (in)fertile phenotypes associated with it, a fertile father opposed to his two infertile sons, can be possibly influenced by genetic background, environmental and epigenetic factors, contributing to different phenotypic expressions of individual/specific genomes.
    2012Conference object Open access Show more
  • Impact of intensive horticulture practices on groundwater content of nitrates, sodium, potassium, and pesticides
    Publication . Melo, A.; Pinto, E.; Aguiar, A.; Mansilha, C.; Pinho, O.; Ferreira, I.
    A monitoring program of nitrate, nitrite, potassium, sodium, and pesticides was carried out in water samples from an intensive horticulture area in a vulnerable zone from north of Portugal. Eight collecting points were selected and water-analyzed in five sampling campaigns, during 1 year. Chemometric techniques, such as cluster analysis, principal component analysis (PCA), and discriminant analysis, were used in order to understand the impact of intensive horticulture practices on dug and drilled wells groundwater and to study variations in the hydrochemistry of groundwater. PCA performed on pesticide data matrix yielded seven significant PCs explaining 77.67% of the data variance. Although PCA rendered considerable data reduction, it could not clearly group and distinguish the sample types. However, a visible differentiation between the water samples was obtained. Cluster and discriminant analysis grouped the eight collecting points into three clusters of similar characteristics pertaining to water contamination, indicating that it is necessary to improve the use of water, fertilizers, and pesticides. Inorganic fertilizers such as potassium nitrate were suspected to be the most important factors for nitrate contamination since highly significant Pearson correlation (r = 0.691, P < 0.01) was obtained between groundwater nitrate and potassium contents. Water from dug wells is especially prone to contamination from the grower and their closer neighbor's practices. Water from drilled wells is also contaminated from distant practices.
    2011-08-09Journal article Restricted access Show more
  • Optimisation of a solid-phase microextraction/HPLC/Diode Array method for multiple pesticide screening in lettuce
    Publication . Melo, A.; Aguiar, A.; Mansilha, C.; Pinho, O.; Ferreira, I.
    A new method was developed for the determination of 10 pesticides widely used in lettuce production (acetamiprid, azoxystrobin, cyprodinil, fenhexamid, fludioxonil, folpet, iprodione, metalaxyl, pirimicarb, and tolyfluanid) using solid-phase microextraction (SPME) and liquid chromatography (HPLC) with diode-array detection (DAD). The extraction performance of four different SPME coatings, polydimethylsiloxane (PDMS), PDMS/divinylbenzene (PDMS/DVB), carbowax/templated resin (CW/TPR), and polyacrylate (PA) was evaluated using an interface SPME–HPLC. CW/TPR fibre was selected as the most appropriate for the extraction of majority of these pesticides. Three variables (pH, NaCl% and extraction time) were considered key factors in the optimisation process. Interactions between these analytical factors and their optimal levels were investigated by response surface methodology based on central composite design. The method allowed the determination of azoxystrobin, cyprodinil, fenehexamid, fludioxonil, folpet, iprodione, and tolyfluanid in lettuce at concentrations between 0.8 and 25.6 mg/kg, i.e., bellow the maximum residues levels allowed for those compounds in lettuce. Lettuce samples that suffered pesticide treatments with folpet and fenehexamid were analysed during days to harvest to study the dissipation behaviour of the pesticides used. Concentration of folpet was 92.8; 53.4; 22.9; 17.9; 7.45; 1.85 mg/kg and concentration of fenhexamid was 158.1; 76.2; 31.0; 27.3; 7.24; 0.87 mg/kg, respectively for t0, t1, t3, t6, t7, t9 days, and not detected at t14 days for the two pesticides.
    2012-02-15Journal article Restricted access Show more