RESUMO
Atrial natriuretic peptide (ANP) is an important regulator of blood pressure (BP). One of the mechanisms whereby ANP impacts BP is by stimulation of nitric oxide (NO) production in different tissues involved in BP control. We hypothesized that ANP-stimulated NO is impaired in the kidneys of spontaneously hypertensive rats (SHR) and this contributes to the development and/or maintenance of high levels of BP. We investigated the effects of ANP on the NO system in SHR, studying the changes in renal nitric oxide synthase (NOS) activity and expression in response to peptide infusion, the signaling pathways implicated in the signaling cascade that activates NOS, and identifying the natriuretic peptide receptors (NPR), guanylyl cyclase receptors (NPR-A and NPR-B) and/or NPR-C, and NOS isoforms involved. In vivo, SHR and Wistar-Kyoto rats (WKY) were infused with saline (0.05 ml/min) or ANP (0.2 µg·kg(-1)·min(-1)). NOS activity and endothelial (eNOS), neuronal (nNOS), and inducible (iNOS) NOS expression were measured in the renal cortex and medulla. In vitro, ANP-induced renal NOS activity was determined in the presence of iNOS and nNOS inhibitors, NPR-A/B blockers, guanine nucleotide-regulatory (G(i)) protein, and calmodulin inhibitors. Renal NOS activity was higher in SHR than in WKY. ANP increased NOS activity, but activation was lower in SHR than in WKY. ANP had no effect on expression of NOS isoforms. ANP-induced NOS activity was not modified by iNOS and nNOS inhibitors. NPR-A/B blockade blunted NOS stimulation via ANP in kidney. The renal NOS response to ANP was reduced by G(i) protein and calmodulin inhibitors. We conclude that ANP interacts with NPR-C, activating Ca-calmodulin eNOS through G(i) protein. NOS activation also involves NPR-A/B. The NOS response to ANP was diminished in kidneys of SHR. The impaired NO system response to ANP in SHR participates in the maintenance of high blood pressure.
Assuntos
Fator Natriurético Atrial/farmacologia , Rim/efeitos dos fármacos , Óxido Nítrico/fisiologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Diurese/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Isoenzimas/metabolismo , Rim/enzimologia , Rim/metabolismo , Testes de Função Renal , Masculino , NG-Nitroarginina Metil Éster/farmacologia , Natriurese/efeitos dos fármacos , Nitratos/urina , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Nitritos/urina , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Receptores do Fator Natriurético Atrial/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
With the purpose of assessing the hygienic conditions of package ready-to-eat vegetables sold in the ABC region- SP, 20 samples of each type of minimally-processed vegetables, watercress, lettuce and cabbage were analyzed, in addition to 25 fresh-cut lettuce samples. Coliforms and Escherichia coli were analyzed by means of the most probable number (MPN) technique, and Salmonella, Listeria monocytogenes and Yersinia enterocolitica by the conventional culture technique. Centrifugal-flotation technique was carried out for enteroparasites detection. Fecal coliforms MNP values higher than 102/g were observed in 60.0% of cabbage, 50.0% of watercress, and 20.0% of lettuce minimally-processed samples. In 48.0% of fresh-cut lettuce samples, the MPN values of fecal coliforms was higher than 2x102/g. Escherichia coli was evidenced in 45.0%, 30.0% and 20.0% of watercress, cabbage and fresh-cut lettuce samples, respectively. Salmonella was isolated from 5.0% and 4.0% of watercress and fresh-cut lettuce samples, respectively, and Yersinia enterocolitica was found on 5.0% of cabbage samples. Enteroparasites were detected on 7.1% of watercress and on 20.0% of fresh-cut lettuce samples. Good manufacturing practices implementation on whole vegetable-produce chain is relevant, in order to assure the availability of safe products to population.
Assuntos
Higiene dos Alimentos , VerdurasRESUMO
With the purpose of assessing the hygienic conditions of package ready-to-eat vegetables sold in the ABC region- SP, 20 samples of each type of minimally-processed vegetables, watercress, lettuce and cabbage were analyzed, in addition to 25 fresh-cut lettuce samples. Coliforms and Escherichia coli were analyzed by means of the most probable number (MPN) technique, and Salmonella, Listeria monocytogenes and Yersinia enterocolitica by the conventional culture technique. Centrifugal-flotation technique was carried out for enteroparasites detection. Fecal coliforms MNP values higher than 102/g were observed in 60.0% of cabbage, 50.0% of watercress, and 20.0% of lettuce minimally-processed samples. In 48.0% of fresh-cut lettuce samples, the MPN values of fecal coliforms was higher than 2x102/g. Escherichia coli was evidenced in 45.0%, 30.0% and 20.0% of watercress, cabbage and fresh-cut lettuce samples, respectively. Salmonella was isolated from 5.0% and 4.0% of watercress and fresh-cut lettuce samples, respectively, and Yersinia enterocolitica was found on 5.0% of cabbage samples. Enteroparasites were detected on 7.1% of watercress and on 20.0% of fresh-cut lettuce samples. Good manufacturing practices implementation on whole vegetable-produce chain is relevant, in order to assure the availability of safe products to population.
Com o intuito de avaliar as condições higiênicas das hortaliças empacotadas e prontas para o consumo, foram analisadas 20 amostras de cada tipo dessas hortaliças - agrião, alface e repolho minimamente processadas e, também, 25 amostras de alface in natura. A determinação de coliformes e Escherichia coli foi realizada por meio de técnica do número mais provável (NMP). Foi utilizada a técnica convencional de cultura para efetuar a pesquisa de Salmonella, Listeria monocytogenes e Yersinia enterocolitica, e a análise parasitológica pela técnica de centrífugoflutuação. O valor de NMP de coliforme fecal acima de 102/g foi encontrado em 60,0% das amostras de repolho, em 50,0% de agrião e em 20,0% de alface minimamente processadas. Em 48,0% das amostras de alface in natura, o valor de NMP de coliformes fecais foi acima de 2x102/g. Escherichia coli foi evidenciada em amostras de agrião, repolho minimamente processados e em alface in natura, respectivamente na proporção de 45,0%, 30,0% e 20,0%.Salmonella foi isolada em 5,0% de amostras de agrião e em 4,0% de alface in natura; e em 5,0% de amostras de repolho foi detectada Yersinia enterocolitica. Os enteroparasitas foram detectados em 7,1% de amostras de agrião e em 20,0% de alface in natura. Os resultados do presente estudo mostram a necessidade de implantar as boas práticas de manufatura de hortaliças em todas as etapas de produção, vi
RESUMO
Estudo realizado pelo Instituto Adolfo Lutz (IAL) - Laboratórios Regionais de Campinas e Santo André, no período de 1997 a 2001, com objetivo de avaliar a freqüência de produtos condenados por matérias estranhas através de denúncias do consumidor. Das 473 amostras estudadas de vários grupos de alimentos, 241 foram realizadas pelo IAL- Campinas e 232 pelo IAL-Santo André. As amostras foram analisadas macroscopicamente e nos casos em que esta análise não foi conclusiva, seguiu-se a metodologia descrita por Rodrigues, Atui, Correia & outros, (1999). Os grupos de alimentos condenados com maior freqüência, segundo denúncias do consumidor foram água mineral, produtos de panificação, bebidas não alcoólicas, biscoitos, leite e derivados e embutidos. As matérias estranhas mais comumente observadas e o número de amostras que foram identificadas nas análises foram: fungos (96), insetos (58), larvas de insetos (24) e fragmentos de insetos (22). A análise microscópica tem sido importante como indicador de boas normas de produção evidenciando as condições higiênicas do produto.