Innovative strategy based on mechanisms to substitute animal testing for ocular toxicity assessment of agrochemical formulations market in Brazil.

Considering the successful employment of alternative methods for eye toxicity assessment of products for regulatory purposes, and the recent advances in Brazilian legislative scenario, which adopted the UN GHS classification system for agrochemical formulations toxicity assessment, there is an emerging demand for strategies that allow the evaluation of such products. Based on this, the present study aimed to address the applicability of a mechanistic-based defined approach for eye toxicity assessment of agrochemical formulations. It was investigated the opacity/permeability, depth and location of corneal injury in bovine cornea, and vascular events in chorioallantoic membrane induced for different Brazilian agrochemicals using a Sequential Testing Strategy (STS). Cytotoxicity induced by the agrochemical formulations was evaluated by Short Time exposure (STE) (OECD TG 491) assay (step 1), corneal injury was investigated by standard Bovine Corneal Opacity and Permeability (BCOP) (OECD TG 437) followed by histopathological evaluation (step 2), and Hen Chorionic-allantoic Membrane test (HET-CAM) was used to evaluate vascular injury (step 3). The results demonstrated that the proposed defined approach enabled a classification corresponding UN GHS classification of agrochemical formulations while minimizing the use of live animals. Therefore, this approach may be useful for categorization of agrochemicals in Brazil according to the new regulatory scenario.

Citotoxicidade da resina acrílica com e sem adesivo temático para confecção da placa de Hawley / Acrylic resin cytotoxicity with and without thematic adhesive for hawley retainer

As placas de Hawley podem ser utilizadas como aparelhos passivos de contenção pós-movimentação ortodôntica, confeccionadas com resina acrílica e grampos de aço. Como todo aparelho removível, seu efeito depende da colaboração do paciente na sua utilização, principalmente de pacientes jovens. A confecção da placa de Hawley com adesivos temáticos surgiu com o objetivo de diminuir esse problema, motivando o paciente quanto ao seu uso. Avaliou-se, in vitro, a biocompatibilidade da resina acrílica com e sem adesivo temático. A citotoxicidade das resinas com e sem adesivos foi avaliada por meio de estudo colorimétrico em células L929, incubadas por 1, 2, 3 e 8 dias, em contato direto com corpos de prova. A quantificação das células viáveis foi realizada por espectrofotometria. Foi verificada baixa viabilidade celular nos dois grupos avaliados, com menores valores de absorbância no grupo das resinas com adesivo temático. Conclui-se que as resinas acrílicas com e sem adesivos temáticos apresentaram elevado grau de citotoxicidade, sendo que as resinas acrílicas sem adesivo apresentaram aumento na viabilidade celular após 8 dias, fator não observado nas resinas temáticas.(AU)

Hawley retainers are commonly used as a passive orthodontic appliance, made with acrylic resin and stainless steel clasps. Like any removable appliance, its effect depends on patient collaboration in its use, especially in young patients. Hawley's retainers with thematic adhesives came to motivate patient and minimize this problem. This study aimed to evaluate in vitro biocompatibility of the acrylic resin with and without the thematic adhesive. The resins cytotoxicity with and without adhesives was evaluated by means of a colorimetric study in L929 cells, incubated for 1, 2, 3, and 8 days, in direct contact with the samples. The viable cell quantification was performed by spectrophotometry. Low cell viability was observed in the two groups evaluated, with lower absorbance values in the resin group with thematic adhesive. It was concluded that acrylic resins with and without thematic adhesives presented high cytotoxicity. Adhesive-free acrylic resins presented an increase in cell viability after 8 days, which was not observed in resins with thematic adhesives. (AU)

Autologous periodontal ligament cells in the treatment of Class III furcation defects: a study in dogs.

AIM: This study aimed to evaluate, histomorphometrically, the use of periodontal ligament cells (PDL cells) in the treatment of class III furcation defects. MATERIAL AND METHODS: PDL cells were obtained from the mandibular tooth extracted from each dog (7), cultured in vitro and phenotypically characterized. Bilateral class III furcation defects were created at mandibular 3rd and 4th premolars and were randomly assigned to: CONTROL GROUP: coronally positioned flap, GTR Group: GTR, Sponge Group: carrier + GTR, Cell Group: carrier + PDL cells + GTR. RESULTS: After 3 months of healing, data analysis demonstrated that the Cell Group presented a superior length of new cementum (4.82 ± 0.61 mm; 3.66 ± 0.95 mm; 2.87 ± 0.74 mm and 1.70 ± 0.60 mm, p < 0.001), a greater extension of periodontal regeneration (3.43 ± 1.44 mm; 2.33 ± 0.95 mm; 1.52 ± 0.39 mm and 0.69 ± 0.59 mm, p = 0.001) and a larger area of new bone (5.45 ± 1.58 mm(2) ; 3.94 ± 1.52 mm(2) ; 2.91 ± 0.56 mm(2) and 1.89 ± 0.95 mm(2) , p = 0.0012), when compared with Sponge, GTR and CONTROL GROUP, respectively. CONCLUSION: The PDL cells in association with GTR may significantly promote periodontal regeneration in class III furcation defects surgically created in dogs.