Abstract This study aims to develop a nano-sized fluoridated layered double hydroxide (LDH)-based release system via hydrothermal treatment for the controlled delivery of fluoride (F-) ions in the oral environment. The synthesis of conventional LDH-type (C-LDH) precursor nanomaterials was conducted using a co-precipitation method at constant pH, and the nanoparticulate-LDH (N-LDH) was synthesized by a hydrothermal procedure. Fluoride LDH (F-LDH) products were obtained through indirect synthesis using the precursor ion-exchange technique by varying the agitation time (2 and 24 h) and temperature (25 and 40 °C) to produce 12 material samples. The materials were characterized by energy dispersive x-ray, hexamethyldisilazane, digital radiography x-ray, Fourier-transform infrared, thermogravimetric analysis, and scanning electron microscopy. Additionally, the F-release kinetic profile was evaluated for 21 d in neutral and acid media with mathematical model analysis. Products with varying F-quantities were obtained, revealing specific release profiles. In general, there was a higher F-release in the acid medium, with emphasis on F-LDH-8. Fluoride-LDH and controlled fluoride delivery was successfully obtained, proving the potential of these nanomaterials as alternative anti-caries agents.

RESUMO Os hidróxidos duplos lamelares vêm ganhando maior atenção de pesquisadores, em decorrência da gama de aplicações, da facilidade de síntese e do baixo custo de produção. Com o crescente conhecimento sobre diversos efeitos da radiação solar sobre o organismo, a utilização de fotoprotetores tem se tornado indispensável. A capacidade de nanoestruturas, como os hidróxidos duplos lamelares, atuarem como matrizes possibilitou melhorias nas formulações fotoprotetoras, tendo em vista os problemas provocados pela radiação, bem como por alguns filtros solares. Este artigo de revisão reúne os avanços mais recentes destas argilas, os hidróxidos duplos lamelares, aplicados à fotoproteção.

ABSTRACT Layered double hydroxides have received more attention from researchers due to their range of applications, ease of synthesis and low cost of production. With broader knowledge about solar radiation effects on the body, the use of sunscreens has become even more important. The ability of some nanostructures, such as layered double hydroxides, to act as matrices has made it possible to obtain improvements in photoprotective formulations, with solutions to problems caused by radiation and sunscreens. This review article brings together the most recent advances of these clays, the layered double hydroxides, applied to photoprotection.

ABSTRACT It is widely known that high fat diet (HFD) can contribute to the advent of health problems. Recent studies have indicated that obesity imposes a hemodynamic overload to the kidneys. In order to further investigate such injuries, two groups of six Swiss mice each were fed with a controlled AIN93G diet or a high fat (AIN93G modified) diet for eight weeks. Blood samples were collected to determine the hormonal, lipid profile, glucose, urea, and creatinine levels. Histopathological and immunohistochemical analysis were carried out to analysis the kidney damage. Fractions of renal membranes were prepared to assess the Na,K-ATPase activity, lipid peroxidation, total cholesterol, and phospholipid content. The results indicated that the blood lipid profile, urea and creatinine was not altered by the HFD. On the other hand, it was observed in HFD diet mice elevated glucose blood levels along with an augment on insulin and a decrease on corticosterone release. HFD provoked a reduction in the diameter of the convoluted tubules and cell volume in Bowman’s capsule and an increased number of positive cells with Na,K-ATPase, but reduced the Na,K-ATPase activity and the cholesterol content in the kidney cell membrane but favored the lipid peroxidation.

Lipophorin (Lp) is the main haemolymphatic lipoprotein in insects and transports lipids between different organs. In adult females, lipophorin delivers lipids to growing oocytes. In this study, the interaction of this lipoprotein with the ovaries of Rhodnius prolixus was characterised using an oocyte membrane preparation and purified radiolabelled Lp (125I-Lp). Lp-specific binding to the oocyte membrane reached equilibrium after 40-60 min and when 125I-Lp was incubated with increasing amounts of membrane protein, corresponding increases in Lp binding were observed. The specific binding of Lp to the membrane preparation was a saturable process, with a Kdof 7.1 ± 0.9 x 10-8M and a maximal binding capacity of 430 ± 40 ng 125I-Lp/µg of membrane protein. The binding was calcium independent and pH sensitive, reaching its maximum at pH 5.2-5.7. Suramin inhibited the binding interaction between Lp and the oocyte membranes, which was completely abolished at 0.5 mM suramin. The oocyte membrane preparation from R. prolixus also showed binding to Lp from Manduca sexta. When Lp was fluorescently labelled and injected into vitellogenic females, the level of Lp-oocyte binding was much higher in females that were fed whole blood than in those fed blood plasma.

OBJETIVO: Avaliar a ação cicatrizante de própolis verde e vermelha, correlacionando ao teor de flavonoides MÉTODOS: Foi realizada a quantificação de flavonoides totais dos extratos etanólicos de própolis verde e vermelha para posterior incorporação em pomada base a 20%. Utilizou-se 20 ratos Wistar distribuídos em quatro grupos: solução salina a 0,9% (S), pomada base (B), pomada própolis verde (G), pomada própolis vermelha (R), todos submetidos à confecção de lesões excisivas na região mediana do dorso. Os ratos foram tratados diariamente durante 15 dias. Neste período foram observados peso; temperatura corporal; diâmetro das feridas. Para análise histológica, amostras das feridas foram coletadas. Ao fim do experimento foram realizadas coleta sanguínea e remoção do rim e fígado para análises bioquímica e histológica. RESULTADOS: Os teores de flavonoides totais das própolis verde (4,50 %) e vermelha (5,92 %) foram elevados (>2 %), mas, embora a segunda apresente teor maior que a primeira, a evolução da própolis verde, macro e histologicamente, foi melhor na reparação das feridas. Não foram observadas nefro ou hepatotoxicidade, resultado corroborado pelos ensaios bioquímicos (TGP e albumina). A própolis influiu na redução de colesterol total, triglicerídeos e glicemia. CONCLUSÃO: Não foi possível correlacionar o teor de flavonoides totais com a ação cicatrizante da própolis. O dado revela a necessidade da elucidação dos flavonoides encontrados em cada classe de própolis para desvendar qual (ou quais) flavonoide(s) seria(m) representativo(s) no processo cicatricial.

OBJECTIVE: To evaluate the healing action of green and red propolis, correlating it with the content of flavonoids. METHODS: We performed quantification of total flavonoids of green and red propolis ethanol extracts for subsequent incorporation in ointment base to 20%. We used 20 Wistar rats divided into four groups: 0.9% saline (S), ointment base (B), green propolis ointment (G) and red propolis ointment (R). All animals were submitted to excisional lesions in the midian back region. The rats were treated daily for 15 days. During this period we observed weight, body temperature and diameters of the wounds. For histological analysis, samples were collected from wounds. At the end of the experiment we performed blood collection and removal of the kidney and liver for biochemical and histological analyzes. RESULTS: The levels of total flavonoids of green (4.50%) and red (5.92%) propolis were high (> 2%), but, while the latter showed a content larger than the former, the evolution of green propolis was better in the repair of wounds, both macroscopically and histologically. There were no nephrotoxicity or hepatotoxicity, a result confirmed by biochemical tests (ALT and albumin). Propolis influenced the reduction of total cholesterol, triglycerides and glucose. CONCLUSION: There was no correlation between total flavonoid contents and the healing action of propolis. This reveals the need for elucidation of the flavonoids found in each class of propolis to unravel which one(s) would be important for the healing process.