Universidade Estadual de Londrina

About: Universidade Estadual de Londrina is a education organization based out in Londrina, Brazil. It is known for research contribution in the topics: Population & Context (language use). The organization has 13052 authors who have published 19291 publications receiving 212123 citations.

Lipoxin A(4) attenuates zymosan-induced arthritis by modulating endothelin-1 and its effects.

Abstract: BACKGROUND AND PURPOSE Lipoxin A4 (LXA4) is a lipid mediator involved in the resolution of inflammation. Increased levels of LXA4 in synovial fluid and enhanced expression of the formyl peptide receptor 2/lipoxin A4 receptor (FPR2/ALX) in the synovial tissues of rheumatoid arthritis patients have been reported. Endothelins (ETs) play a pivotal pro-inflammatory role in acute articular inflammatory responses. Here, we evaluated the anti-inflammatory role of LXA4, during the acute phase of zymosan-induced arthritis, focusing on the modulation of ET-1 expression and its effects. EXPERIMENTAL APPROACH The anti-inflammatory effects of LXA4, BML-111 (agonist of FPR2/ALX receptors) and acetylsalicylic acid (ASA) pre- and post-treatments were investigated in a murine model of zymosan-induced arthritis. Articular inflammation was assessed by examining knee joint oedema; neutrophil accumulation in synovial cavities; and levels of prepro-ET-1 mRNA, leukotriene (LT)B4, tumour necrosis factor (TNF)-α and the chemokine KC/CXCL1, after stimulation. The direct effect of LXA4 on ET-1-induced neutrophil activation and chemotaxis was evaluated by shape change and Boyden chamber assays respectively. KEY RESULTS LXA4, BML-111 and ASA administered as pre- or post-treatment inhibited oedema and neutrophil influx induced by zymosan stimulation. Zymosan-induced preproET-1 mRNA, KC/CXCL1, LTB4 and TNF-α levels were also decreased after LXA4 pretreatment. In vitro, ET-1-induced neutrophil chemotaxis was inhibited by LXA4 pretreatment. LXA4 treatment also inhibited ET-1-induced oedema formation and neutrophil influx into mouse knee joints. CONCLUSION AND IMPLICATION LXA4 exerted anti-inflammatory effects on articular inflammation through a mechanism that involved the inhibition of ET-1 expression and its effects.

Resistência à penetração de um Latossolo Vermelho Amarelo do Cerrado sob diferentes sistemas de manejo

Abstract: Embora associada a adocao de tecnologias de conservacao do solo, a intensificacao dos sistemas de producao agropecuaria tem induzido a um dos principais problemas enfrentados pelos agricultores, a compactacao do solo, seja em sistemas de plantio direto ou em sistemas de plantio convencional e pastagem. Este estudo foi realizado em Rio Verde, GO, em Latossolo Vermelho Amarelo, nos seguintes sistemas: plantio direto ha 14 anos (SD14); plantio direto ha oito anos (SD8); plantio direto ha dois anos (SD2); preparo convencional (PC); pastagem (P) e floresta (F). A resistencia a penetracao do solo foi determinada utilizando-se o penetrometro de Impacto Modelo IAA/Planalsucar - Stolf, a partir da superficie do solo ate a profundidade de 0,40 m; determinaram-se, tambem, a densidade do solo e a granulometria. O plantio convencional apresentou menor resistencia a penetracao, na profundidade 0-0,10 m, enquanto o SD2 indicou maior resistencia a penetracao ate 0,40 m de profundidade. Abaixo da profundidade de 0,15 m nao houve diferenca significativa entre os tratamentos PC, SD8, SD14. Os dois primeiros anos de adocao do sistema de plantio direto sao criticos quanto a resistencia a penetracao nas camadas superficiais do solo.

Chlorination treatment of aqueous samples reduces, but does not eliminate, the mutagenic effect of the azo dyes Disperse Red 1, Disperse Red 13 and Disperse Orange 1

Abstract: The treatment of textile effluents by the conventional method based on activated sludge followed by a chlorination step is not usually an effective method to remove azo dyes, and can generate products more mutagenic than the untreated dyes. The present work evaluated the efficiency of conventional chlorination to remove the genotoxicity/mutagenicity of the azo dyes Disperse Red 1, Disperse Orange 1, and Disperse Red 13 from aqueous solutions. The comet and micronucleus assays with HepG2 cells and the Salmonella mutagenicity assay were used. The degradation of the dye molecules after the same treatment was also evaluated, using ultraviolet and visible absorption spectrum measurements (UV-vis), high performance liquid chromatography coupled to a diode-array detector (HPLC-DAD), and total organic carbon removal (TOC) analysis. The comet assay showed that the three dyes studied induced damage in the DNA of the HepG2 cells in a dose-dependent manner. After chlorination, these dyes remained genotoxic, although with a lower damage index (DI). The micronucleus test showed that the mutagenic activity of the dyes investigated was completely removed by chlorination, under the conditions tested. The Salmonella assay showed that chlorination reduced the mutagenicity of all three dyes in strain YG1041, but increased the mutagenicity of Disperse Red 1 and Disperse Orange 1 in strain TA98. With respect to chemical analysis, all the solutions showed rapid discoloration and a reduction in the absorbance bands characteristic of the chromophore group of each dye. However, the TOC was not completely removed, showing that chlorination of these dyes is not efficient in mineralizing them. It was concluded that conventional chlorination should be used with caution for the treatment of aqueous samples contaminated with azo dyes.