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The rapid progress of nanomedicine, especially in areas related to medical imaging and diagnostics, has motivated the development of new nanomaterials that can be combined with biological materials for specific medical applications. One such area of research involves the detection of specific DNA sequences for the early diagnosis of genetic diseases, using nanoparticles-containing genosensors. Typical genosensors devices are based on the use of sensing electrodes - biorecognition platforms - containing immobilized capture DNA probes capable of hybridizing with specific target DNA sequences. In this paper we show that upon an appropriate design of the biorecognition platform, efficient sandwich-type genosensors based upon DNA-AuNPs nanocomplexes can be efficiently applied to the detection of a Systemic Arterial Hypertension (SAH) polymorphism located in intron 16 of the Angiotensin-converter enzyme (ACE) gene. Since SAH is intimately related to heart diseases, especially blood hypertension, its early detection is of great biomedical interest. The biorecognition platforms were assembled using mixed self-assembled monolayers (SAMmix), which provided the immobilization of organized architectures with molecular control. Detection of the DNA target sequence at concentrations down to 1 nM was carried out using electrochemical impedance spectroscopy (EIS). We show that the use of EIS combined with specific nanobiocomplexes represents an efficient method for the unambiguous detection of complementary DNA hybridization for preventative nanomedicine applications.

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This paper describes the application of a glassy carbon electrode modified with a thin film of mesoporous silica/multiwalled carbon nanotubes for voltammetric determination of the fungicide carbendazim (CBZ). The hybrid material, (SiO2/MWCNT), was obtained by a sol-gel process using HF as the catalyst. The amperometric response to CBZ was measured at +0.73 V vs. Ag/AgCl by square wave voltammetry at pH 8.0. SiO2/MWCNT/GCE responded to CBZ in the linear range from 0.2 to 4.0 µmol L(-1). The calculated detection limit was 0.056 µmol L(-1), obtained using statistical methods. The SiO2/MWCNT/GCE sensor presented as the main characteristics high sensitivity, low detection limit and robustness, allowing CBZ determination in untreated real samples. In addition, this strategy afforded remarkable selectivity for CBZ against ascorbic and citric acid which are the main compounds of the orange juice. The excellent sensitivity and selectivity yielded feasible application for CBZ detection in orange juice sample.

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Nanomaterials such as carbon nanotubes (CNTs) and nanoparticles have received enormous attention in analytical areas for their potential applications as new tools for biotechnology and life sciences. Most of these possible applications involve the use of CNTs and related materials as vehicles for drug delivery and/or gene therapy. In this study, we introduce a methodology to evaluate the interactions between CNTs/dendrimers nanoconjugates and phospholipid biomembrane models, using the Langmuir film balance technique. Our main goal was to elucidate the action of engineered nanomaterials in cell membranes, at the molecular level, using a membrane model system. The penetration of single-walled carbon nanotubes (SWCNTs)/polyamidoamine dendrimer nanocomplexes into dipalmitoylphosphatidylcholine monolayers was pronounced, as revealed by adsorption kinetics and surface pressure measurements. These findings suggest that SWCNTs were able to interact even at high surface pressure values, ∼30 mN/m. Therefore, the results confirm that the presence of the nanomaterial affects the packing of the synthetic membranes. We believe the methodology introduced here may be of great importance for further nanotoxicity studies.

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Lapachol administrado a ratas (Rattus norvegicus Berkenhout, 1769): Teratogênico ou embriotóxico? Devido a controvérsias na literatura sobre os efeitos embriotóxicos e teratogênicos do lapachol, o presente trabalho teve como objetivo investigar as conseqüências da administração desta droga (100 and 200 mg/kg) a ratas Wistar prenhes no nono dia pós-coito, para investigar sua possível toxicidade no organismo materno e fetal. Dados maternos indicaram que na dose de 100 mg/kg o lapachol não foi tóxico. Enquanto que na dose de 200 mg/kg induziu uma leve toxicidade, estabelecendo a dose limite para a avaliação da toxicidade do desenvolvimento. As duas doses causaram redução de peso corporal e reabsorções, mas não causaram malformações. Assim, este estudo sugere um efeito embriotóxico, mas não teratogênico do lapachol em ratas Wistar.

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Lapachol administrado a ratas (Rattus norvegicus Berkenhout, 1769): Teratogênico ou embriotóxico? Devido a controvérsias na literatura sobre os efeitos embriotóxicos e teratogênicos do lapachol, o presente trabalho teve como objetivo investigar as conseqüências da administração desta droga (100 and 200 mg/kg) a ratas Wistar prenhes no nono dia pós-coito, para investigar sua possível toxicidade no organismo materno e fetal. Dados maternos indicaram que na dose de 100 mg/kg o lapachol não foi tóxico. Enquanto que na dose de 200 mg/kg induziu uma leve toxicidade, estabelecendo a dose limite para a avaliação da toxicidade do desenvolvimento. As duas doses causaram redução de peso corporal e reabsorções, mas não causaram malformações. Assim, este estudo sugere um efeito embriotóxico, mas não teratogênico do lapachol em ratas Wistar.

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Estudos prévios com o lapachol, administrados durante o período de organogênese, indicaram que o fitofármaco é embriotóxico. A exposição de ratas prenhes a xenobióticos por longo período pode causar toxicidade materna responsável por alterações morfológicas do concepto. No presente trabalho avalia-se o efeito do lapachol, administrado no nono dia de prenhez, sobre o organismo materno e o sistema morfogenético do concepto. Ratas Wistar foram distribuídas em quatro grupos: controle (1 ml de água destilada), veículo (1 ml de solção hidroalcoólica), lapachol 100 (L - 100) e 200 (L - 200) mg/kg peso corporal. Tratamento por via gástrica em dose única. Mediu-se peso corporal e consumo de ração. No 21º dia os animais foram sacrificados por exsanguinação total sob anestesia. No soro foram dosadas TGP e uréia. Procedeu-se á autópsia e á remoção de fígado, rins (pesados e fixados para análise anatomopatológica) e trato reprodutor materno. O vários foram pesados e os corpos lúteos contados. Nos cornos uterinos contaram-se implantes, reabsorções, e fetos mortos. Fetos e placentas foram pesados. Ratas tratadas com L - 200 tiveram peso de fígado e de ovários menor que os demais grupos; aumento da concentração de TGP e de uréia e 83% de mortes de conceptos. Ratas tratadas com L - 100 tiveram 32% de mortes de conceptos. os resultados indicam possibilidade de toxicidade materna com a dose maior de lapachol. Pode-se concluir que o lapachol ou seus produtos biotransformados, agem diretamente sobre o sistema morfogenético do embrião e doses elevadas podem ter seu efeito potencializado por toxicidade materna leve.

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St John's wort (Hypericum perforatum) is a medicinal plant used in the treatment of depression and other psychiatric disorders. In the present paper, the toxicity of H. perforatum administered to female rats during the period of organogenesis (day 9-15 of pregnancy) was evaluated. Thirty inseminated Wistar rats were randomly distributed into control and treated groups, which received, by gavage, 0.5 mL of saline and 36 mg/kg body weight of Jarsin dried extract diluted into 0.5 mL of saline, respectively. Maternal toxicity was evaluated through: water and food intake, body weight gain, piloerection, locomotor activity, diarrhea and death occurrence. Animals were killed on day 21 of pregnancy, when fetuses and placentas were removed and weighed. The indices of implantation and resorption were calculated. Clinical signs of maternal toxicity were not observed and none of the variables analysed showed statistically significant differences. In the dose administered in the experimental model used, H. perforatum does not seem to be toxic to the mother nor to interfere with the progress of gestation during organogenesis.

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A simple spectrophotometric method is described for resolving binary mixtures of some food dyes: Amaranth, Brilliant Blue, Sunset Yellow and Tartrazine, using the first-derivative spectra with measurements at zero-crossing wavelengths. Analytical curves are linear up to 20 mg L(-1). Standard deviations of 1.30, 2.22, 1.93 and 0.81% were obtained for synthetic binary mixtures of 2 mg L(-1) of Amaranth, Brilliant Blue, Sunset Yellow and Tartrazine, respectively. Before the spectrophotometric measurements, the dyes were sorbed onto polyurethane foam and recovered in sodium dodecyl benzene sulfonate solution. Therefore, matrix complexity was eliminated and simple spectra were obtained. The method was very satisfactorily used for determining the colorants in synthetic mixtures, with recoveries in the 96 - 101% range. Detection limit values were dependent on the colorant combination investigated. Commercial products containing binary combinations of these dyes in different ratios (from 1:1 to 1:8) were analyzed. The results were compared with those obtained by HPLC; very similar values were found by the two methods.