77 resultados para 3.4-benzpyrene


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The endopeptidase 22.19 (EC 3.4.22.19) has been associated with the metabolism of neuropeptides by its ability to convert small enkephalin-containing peptides (8 to 13 amino acids) into enkephalins. In addition, this enzyme cleaves the Arg8-Arg9 bond of neurotensin and the Phe5-Ser6 bond of bradykinin. We analyzed the circadian variation of endopeptidase 22.19 in the whole and individual areas of the rat brain. Endopeptidase 22.19 activity was analyzed by high-performance liquid chromatography (HPLC) using bradykinin as an operative substrate. Enzymatic specific activities were analyzed by rhythmometric methods and indicate a circadian fluctuation of endopeptidase 22.19 specific activity (mU of enzyme/mg of protein) in the whole brain [p < 0.001, mesor (M) = 7.62, amplitude (A) = 2.89, and acrophase (phi) = 23:08 h], striatum (p < 0.001, M = 2.92, A = 0.62, phi-23:03 h), hypothalamus (p < 0.001, M = 3.15, A = 0.86, phi-01:12 h), periaqueductal gray matter (p < 0.005, M = 2.62, A = 0.34, phi = 22:35 h), and cerebellum (p < 0.0 14, M = 4.27, A = 0.88, phi = 17:12 h). The circadian rhythmicity in endopeptidase 22.19 specific activity suggests that light may have an effect on the peptidase activity in whole brain and in areas of the central nervous system and may be essential for the mechanisms of circadian fluctuations of neuropeptides in the brain.

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Diuron (3-(3,4-Dichlorophenyl)-1,1-dimethylurea) is a substituted urea herbicide widely used on agricultural crops such as soy, cotton and sugar cane. In a previous long-term study this herbicide exerted carcinogenic activity on the urinary bladder and renal pelvis mucosa of Wistar rats and breast of mice. Also, it was shown to be carcinogenic to the mice skin in a initiation-promotion assay. In 1997, the northamerican EPA evaluated Diuron as a “known/likely” carcinogen for humans (USEPA, 2004). In a previous study developed at this laboratory, male Wistar rats treated with Diuron 2500 ppm during 20 weeks presented increased indices of cell proliferation and incidences of simple urothelial hyperplasia (HS) in the urinary bladder. Under scanning electron microscopy (SEM) severe urothelial necrosis and hyperplasia were observed. However, in that study the urinary bladders of animals exposed to lower doses of Diuron were not examined under SEM. Therefore, the possible dose-response influence of Diuron on the urothelium under SEM is not known. The present study aimed to analyze under SEM the urinary bladder of male Wistar rats exposed to 125 ppm, 500 ppm and 2500 ppm doses of Diuron through diet during 20 weeks and to compare to the previous histological findings in the same material. Under SEM, 125 ppm and 2500 ppm groups presented significantly (p<0,05) increased incidences of simple hyperplasia, i.e., 7/10 and 8/10 respectively, compared to control group and the 500 ppm group The sensitivity of SEM was higher since it detected a 45% incidence of hyperplasiaswhile the histological analysis found only 27%. Considering SEM as the gold-standard, histology showed a 44% sensitivity, 86.4% specificity, a positive predictive value of 72,7% and negative predictive value of 65,5% and accuracy of 67,5%. Scanning Electron Microscopy...(Complete abstract click electronic access below)

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Diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is a substituted urea herbicide widely used in crops of sugar cane, cotton and soybeans. In 1997, this agent has been classified by the United States Environmental Protection Agency as known/likely human carcinogen because it induced tumors in the urinary bladder and renal pelvis of rats, and breast and skin of mice exposed to 2500 ppm for feed for two years. A previous study from our group demonstrated dose-response relationship in the gene expression profile associated with severe necrosis on bladder urothelium and increased incidence of simple hyperplasia in male Wistar rats treated with different concentrations of diuron for 20 weeks. To check how early the molecular changes occurs, rats were fed for 7 days with diets containing diuron at 0, 125, 500 or 2500 ppm. The main observations recorded were urothelium ultrastructural alterations and disruptions of molecular pathways associated with cell-cell interaction and the tissue organization maintenance. Particularly, the gene Glypican 3 (Gpc3), a surface proteoglycan related to cellular adhesion and apoptosis induction, was down regulated on urothelium exposed to 2500ppm diuron for 7 days and 20 weeks. The aim of this study was validate by quantitative RT-PCR real time, the reduced Gpc3 gene expression in epithelial cells of the urinary bladder of male Wistar rats treated with different concentrations of diuron for 7 days and 20 weeks. The endogenous control of the quantitative PCR real time technique was the β-actin gene and the target was the gene Gpc3. The relative quantification (RQ) was obtained by the method of relative quantification 2-ΔΔCt . Animals exposed to diuron for 7 days or for 20 weeks presented reduction of Gpc3 gene expression compared to the control group. This reduction was statistically significant only for the 7 days study. Moreover, by comparing animals exposed for 7 days with the exposed for 20 weeks, it was ...

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Coumarin is a natural active compound that can be found in many plants. The coumarins have many properties such as bronchodilator, anti-inflammatory, antioxidant, anticoagulant, antibiotics, immunomodulatory, antimicrobial and antiviral, thus, they are widely used in medical applications. More recently the coumarin derivatives have attracted the interest of many research groups in the field of new materials, for example the possibility of their use as sensitizers in dye-sensitized solar cells (DSSC) and lasers. The MCRs are defined as a process in which three or more reactants are combined in the same reaction pot, resulting in products with good structural complexity a single step, in addition to economy of atoms and selectivity and is a very important feature in modern synthetic methodology. In this work we investigated the use of niobium pentachloride as catalyst of the multicomponent reactions between phenolic derivatives, various aromatic aldehydes and β-diester derivatives in the synthesis of 4-aryl-3,4-dihydrocoumarin derivatives. The reactions were carried out at room temperature, under inert atmosphere (N2), using dichloromethane anhydrous (CH2 Cl2) as solvent, with a reaction time of most 120 hours. The products were isolated by column chromatography on silica gel and submitted to spectrometric and spectroscopic analysis. The results show that NbCl5 is an excellent agent for promoting the synthesis of 4-aryl-3,4-dihydrocoumarin derivatives through multicomponent reactions, obtaining yields varying from 45 to 95%

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Botryosphaeran, a (1 -> 3; 1 -> 6)-beta-D-glucan produced by Botryosphaeria rhodina, and laminarin were hydrolysed by two fungal beta-glucanases predominantly of the 1,3-type produced by B. rhodina and Trichoderma harzianum Rifai grown on botryosphaeran as sole carbon source. Both beta-glucanase preparations presented different modes of attack on botryosphaeran and laminarin. Laminarin was hydrolysed to the extent of similar to 50% in 1 hand 100% within 24 h, and its hydrolysis products were mainly glucose and gentiobiose, and lesser amounts of laminaribiose and oligosaccharides of DP 3-4 during the early stages of hydrolysis, while botryosphaeran 'yielded mainly glucose and gentiobiose with some trisaccharide, but no laminaribiose or tetrasaccharide when hydrolysed by the T. harzianum enzyme. By contrast, B. rhodina beta-1,3-glucanases produced predominantly glucose during all stages of botryosphaeran hydrolysis. Some physicochemical properties of the 1,3- and 1,6-beta-glucanases, and beta-glucosidases contained in the two fungal P-glucanase preparations are also described for the first time. (c) 2006 Elsevier Ltd. All rights reserved.