Use of selenium fertilizers for production of Se-enriched Kenaf (Hibiscus cannabinus): effect on Se concentration and plant productivity

Due to selenium (Se) deficiency, Se fortification of food and feed is applied in many countries. Therefore, potential use of Se-enriched kenaf was investigated based on its Se accumulation, its potential to transform accumulated Se to other Se species, and effect of Se accumulation on its growth. Kenaf was grown with different levels of two Se fertilizers (selenite and selenate) at concentrations ranging from 0 to 4 mg Se (kg soil)(-1). Total Se concentrations in the plants grown on selenate-treated soil amounted to (1019 +/- 136) mg Se (kg dry weight)(-1) and were much higher compared to plants grown on selenite-treated soil. Identified Se species were selenite, selenate, Se-methionine, and Se-cystine. Biomass yield, net photosynthesis, and chlorophyll index of the plants decreased when plants were grown on soils treated with high doses of selenate

Inclusões de quitosana no subcutâneo de rato: avaliação clínica, histológica e morfométrica Chitosan inclusions in the subcutaneous space of rats: clinic, histologic and morphometric evaluation

FUNDAMENTOS: A quitosana é polímero derivado da quitina, com vários tipos de aplicação na área médica. OBJETIVO: Avaliar a biocompatibilidade de membranas de quitosana no subcutâneo de ratos. MÉTODOS: Foram utilizados 20 ratos "Wistar" machos, nos quais foram implantadas membranas de quitosana, na região mediana dorsal. Os animais foram sacrificados: sete, 15, 30 e 60 dias após a cirurgia, tendo sido avaliados clinicamente durante o período experimental e com fotodocumentação no momento do sacrifício. Após o sacrifício, as membranas e tecidos adjacentes foram removidos e preparados para exame histológico e morfométrico. RESULTADOS: Nenhum animal apresentou efeitos adversos que pudessem ser atribuídos à implantação das membranas. O exame histológico mostrou que as inclusões são lisas e homogêneas e não são colonizadas por células do hospedeiro, sendo circundadas por pseudocápsula composta por fibroblastos e células inflamatórias. A morfometria da pseudocápsula revelou espessura semelhante durante todo o período experimental (P>0,05). CONCLUSÃO: A quitosana pode ser opção para uso como implante não integrado. Novos estudos devem ser realizados para comprovar a biocompatibilidade a longo prazo.<br>BACKGROUND: Chitosan is a polymer derivative from chitin applied in many medical specialties. OBJECTIVE:To evaluate the biocompatibility of chitosan membranes used as inclusion material into subcutaneous of rats. METHODS: Twenty male Wistar rats received chitosan membranes into the subcutaneous area of the dorsal medial region. The animals were randomly divided in four groups with 5 animals each, sacrificed on 7th (G1), 15th (G2), 30th (G3) and 60th (G4) postoperative day (PO). All animals were clinically evaluated daily and by photo-documentation at the sacrifice moment. The animals and the material were assessed for evidence of host response by histological and morphometric evaluation of the implants and the surrounding soft tissues. The material was fixed in 10% formalin and then the sections were stained with hematoxylin and eosin. RESULTS: None of animals presented side effects attributable to the implants. The histological evaluation showed smooth and homogeneous inclusions with no host cells inside and were encircled by a pseudocapsule of fibroblasts and inflammatory cells. The morphometric evaluation showed no statistical difference between different groups (P>0.05)