ISEP - DM – Outros
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Browsing ISEP - DM – Outros by advisor "Domingues, Valentina Maria Fernandes"
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- Determination of permethrin and its metabolite in brains and urines of rats by GC-ECD and GC-MSPublication . Cavaliere, Maria; Domingues, Valentina Maria Fernandes; Correia-Sá, Luísa; Gabbianelli, RositaSynthetic pyrethroids are pesticides derived from naturally occurring pyrethrins, taken from pyrethrum of dried Chrysanthemum flowers. Pyrethroid insecticides are one of the most commonly used residential and agricultural insecticides. Many pyrethroids can significantly harm the nervous system. Permethrin could be one of the factors involved in the onset of neurodegenerative diseases. The present study aims to evaluate in brain, the effect that can induce the exposure to permethrin, during early life of female rats (from 6 to 21 days of life). Therefore, have been examined the concentrations of permethrin and its main metabolite (3-PBA) in the brain and urine in female rats sacrificed the day after and 14 days after treating. The different concentrations of permethrin and 3-PBA (after 24h and after 14 days in the end of treatment) were obtained using two different methods. The evaluation of permethrin by liquid-liquid extraction and GC-ECD was performed. The levels of the 3-PBA (in urine and brains) were obtained by SPE procedure and GC-MS using the 2- PBA as internal standard.
- Determination of permethrin and its metabolites in hearts and urines of rats by GC-ECD and GC-MSPublication . Mercuri, Ilaria; Gabbianelli, Rosita; Domingues, Valentina Maria Fernandes; Correia-Sá, LuísaPyrethroids are pesticides very used in agriculture, which tend to replace organophosfate and carbamate insecticides. These pesticides have shown to exhibit cardiotoxicity. The aim of this study was to assess if cardiotoxicity is due to direct or indirect effects (metabolites) of permethrin on hearts. There were studies 8 rats; three of them were sacrificed after 24 of the end of treatment with permethrin and the other four were sacrificed after 14 days of the end of treatment. Afterwards hearts and urines were collected. The amounts of permethrin and its main metabolite (3-PBA) were evaluated on hearts and urines of female rats which were treated with permethrin and sacrificed the day after and 14 days after the treatment. Moreover has been highlighted the difference of amount of permethrin and its metabolite between rats sacrificed immediately at the end of treatment and those sacrificed after 14 days. The study of permethrin was accomplished by liquid-liquid extraction and GC-ECD. The evaluation of 3-PBA was performed by SPE procedure with 2-PBA as internal standard and gas-chromatography GC-MS. The concentration of permethrin in hearts is basically the same in 24h and 14 days. The 3-PBA concentration in urines decreased 50 times from 24h to 14 days. In hearts the 3-PBA level also decrease but only 2.24 times and a high variation of results were achieved in rats after 14 days.
- Evaluation of a pyrethroid metabolite (3-pba) in urine of children affected by asd (autism spectrum disease)Publication . Orazi, Mattia; Domingues, Valentina Maria FernandesThe described method permits the determination one of the most common metabolite of the pyrethroids permethrin, cypermethrin, deltamethrin, λ-cyhalothrin, fenvalerate, phenothrin and β-cyfluthrin in human urine: The 3-phenoxybenzoic acid (3-PBA) . After alkaline hydrolysis to release the conjugated carboxylic acid metabolite, the analytes were separated from the matrix by means of solid-phase extraction using a reversed-phase/strong cation exchange column. The components of the eluate were converted to their Hexafluoroisopropane esters and extracted in hexane. Separation and quantitative analysis of this pyrethroid metabolite was carried out by capillary gas chromatography and mass selective detection. 2-Phenoxybenzoic acid served as an internal standard. The detection limits was 0,0038 μg per ml urine. The relative standard deviations of the within-series imprecision were always less than 10%. Using this method we determined the elimination of 3-PBA in 46 children( 24 autistics,22 controls), the average values in urine of each population were 1,48 µg/ml in ASD (Variance 4,94) and 0,63 µg/ml in controls (Variance 0,22).
- Evaluation of permethrin in rats brainsPublication . Valentini, Francesco; Domingues, Valentina Maria FernandesPyrethrins and pyrethroids interfere with the functions of the nervous system. Exposure to very high levels of these substances can cause dizziness, headaches, nausea, muscle spasms, weakness, loss of consciousness and convulsions. There is no evidence that pyrethrins and pyrethroids can affect the reproductive capacity of human beings but some studies have shown reduced fertility in animals. The Occupational Safety and Health Administration (OSHA) has established in 5 milligrams of pyrethrins per cubic meter of air over 40 hours of weekly work, the concentration limit of this substance in the workplace. From this study, it is possible to conclude that is possible to use a methodology to quantify permethrin residues in rats’ brains. It was proved that permethrin can remain in brain during long time. 50% of the rats have permethrin after 24h. The exposition with alkaline water increases the levels of permethrin in brain. By other side, vitamin E, may act as a protecting factor decreasing the levels until not detected.
- Otimização metodológica para a avaliação do metabolito de permetrina em pêlo de ratoPublication . Pellegrini, Claudia; Domingues, Valentina Maria FernandesPyrethroids are insecticides with worldwide commercial and retail usage and they provide benefits such as increased supply of crops, fruits and vegetables, as well as control of diseases transmitted through insects that affect humans and livestock. Despite their benefits, many pesticides are neurotoxic compound that induce acutely toxic effect at high doses and can potentially exert more subtle effects at lower doses though different exposure routes. The permethrin is one of the most widely used pyrethroids that in mammals, once absorbed, is rapidly distributed to various organs/tissues and is transformed into metabolites, 3-(2,2-dichlorovinyl)-2,2-dimethyl- (1-cyclopropane) carboxylic acid (DCCA) and the 3-phenoxybenzoic acid (3-PBA). The 3- PBA has been used in numerous studies for the biomonitoring of exposure in occupationally and environmentally exposed individual. The aim of our work was to develop an analytical method for the quantification of 3-PBA in hair samples. Hair is a non-invasive biological material useful in the biomonitoring of trace elements because it is a vehicle for substance excretion from the body, and it permits evaluating longterm exposure. Our animal’s model are rat exposed to permethrin in early days of them life and we took hair rat’s samples after 22 and 60 days. The hair has been analyzed with the purpose to assess if 3-PBA content could be used as biomarkers on this sample. The analytical method comprises five main steps: preparation of hair samples, decontamination step, extraction of analytes, derivatization and subsequent instrumental analysis by gas chromatography (GC) and detection using ion trap mass spectrometry (MS). The analytes were isolated from hair with recoveries of 78%. The limit of detection and quantification ensured by the method are 0.92 µg/mg and 3.06 µg/mg, respectively. The results presented in this work show the potential of GC-MS based method for the extraction of 3-PBA in hair of rat aged 22 days, but I could not be determined the 3-PBA concentration in hair of rat aged 60 days.