A layer-by-layer film of chitosan in a taste sensor application

Chitosan is alternated with sulfonated polystyrene (PSS) to build layer-by-layer (LBL) films that are used as sensing units in an electronic tongue. Using impedance spectroscopy as the principle method of detection, an array using chitosan/PSS LBL film and a bare gold electrode as the sensing units was capable of distinguishing the basic tastes - salty, sweet, bitter, and sour - to a concentration below the human threshold. The suitability of chitosan as a sensing material was confirmed by using this sensor to distinguish red wines according to their vintage, vineyard, and brands.

Chitosan-pectin multiparticulate systems associated with enteric polymers for colonic drug delivery

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

AC Biosusceptometry as a Tool for Monitoring the Gastrointestinal Transit of Multiparticulate Drug Delivery System

Drug delivery systems based on natural polysaccharides, such as chitosan (CS) and pectin (PC), rather than on synthetic polymers, have been widely studied. Some reasons for that are low toxicity and costs and high biodegradability of the formers. A multiparticulate system based on CS and PC was developed in our laboratories, including the addition of an enteric polymer, cellulose acetate phtalate (CAP). Such improvement promoted stronger gastric and enteric resistances, as assessed in vitro, making the systems more selective to enzymatic degradation in the colon. Although in vitro dissolution tests can simulate some properties concerning the gastrointestinal transit (GT), collaborating to characterize the systems behavior in the biological fluids, frequently they do not result in satisfactory in vitro/in vivo correlations. The objective of this work was to follow in vivo the GT of the particles developed by means of AC biosusceptometry (ACB), a non-invasive and of low cost methodology. The particles containing ferrite in powder form were prepared by complex coacervation using an ideal 3:1:1 mass ratio for PC:CS:CAP. The magnetic particles were administered to healthy volunteers by oral route. The GT was monitored by using multi-sensor ACB system and the signal acquisition was performed every IS min until the colonic region was reached. By means of ACB technique, it was possible to acquiring images generated by the magnetic particles within the whole gastrointestinal tract including the colonic region. Variable particles transit times were observed among the volunteers, but without interference on the mapping of the particles until the colonic region. The particles were able to produce magnetic field strong enough to generate signals adequate for mapping the particles. The results suggest that integral particles reached the colon, after they resisted against gastric and enteric media. Studies associating transit time and in vivo drug release are in development in order to confirm the efficiency of the systems.

Testicular structure and description of the seminal pathway in Leporinus macrocephalus (Anostomidae, Teleostei)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Exames parasitológicos, imunoistoquímicos e histopatológicos para detecção de Leishmania chagasi em tecidos esplênicos de cães com leishmaniose visceral

O propósito do presente trabalho foi o estudo da Leishmaniose Visceral Canina - LVC por meio de métodos parasitológicos e imunoistoquímicos para a detecção de formas amastigotas de Leishmania (L.) chagasi em baço, além de descrever a histopatologia das lesões esplênicas em 34 cães, com diferentes manifestações clínicas da LVC, eutanasiados pelo Centro de Controle de Zoonoses de Ilha Solteira, SP. Esses animais foram examinados clinicamente antes da eutánásia e de acordo com os sinais clínicos da LVC, foram classificados em três grupos: assintomáticos (8 cães), oligossintomáticos (17 cães) e sintomáticos (9 cães). Após a realização desses exames, dos 34 cães, 22 (64,7%) estavam positivos e 12 (35,3%) negativos. Desses cães positivos, 1/22 (4,5%) era assintomático, 12/22 (54,5%) eram oligossintomáticos e 9/22 (40,1%) sintomáticos. Pela histopatologia, os cães, especialmente os sintomáticos apresentavam o baço com inflamação crônica e espessamento na região capsular e trabecular, além de extensa alteração morfológica na polpa vermelha e branca pela presença de grande quantidade de macrófagos repletos de amastigotas, pela reação granulomatosa inflamatória e pelas áreas hemorrágicas. Os exames histopatológicos e a detecção microscópica direta da L. (L.) chagasi revelaram que o baço é um órgão útil para auxiliar no diagnóstico da LVC. A coloração imunoistoquímica foi a que detectou o maior número de tecidos esplênicos positivos com amastigotas, além de elucidar os casos suspeitos pelos exames parasitológicos, principalmente, nos animais assintomáticos ou oligossintomáticos.

Screening and Production Study of Microbial Xylanase Producers from Brazilian Cerrado

Hemicelluloses are polysaccharides of low molecular weight containing 100 to 200 glycosidic residues. In plants, the xylans or the hemicelluloses are situated between the lignin and the collection of cellulose fibers underneath. The xylan is the most common hemicellulosic polysaccharide in cell walls of land plants, comprising a backbone of xylose residues linked by beta-1,4-glycosidic bonds. So, xylanolytic enzymes from microorganism have attracted a great deal of attention in the last decade, particularly because of their biotechnological characteristics in various industrial processes, related to food, feed, ethanol, pulp, and paper industries. A microbial screening of xylanase producer was carried out in Brazilian Cerrado area in Selviria city, Mato Grosso do Sul State, Brazil. About 50 bacterial strains and 15 fungal strains were isolated from soil sample at 35 A degrees C. Between these isolated microorganisms, a bacterium Lysinibacillus sp. and a fungus Neosartorya spinosa as good xylanase producers were identified. Based on identification processes, Lysinibacillus sp. is a new species and the xylanase production by this bacterial genus was not reported yet. Similarly, it has not reported about xylanase production from N. spinosa. The bacterial strain P5B1 identified as Lysinibacillus sp. was cultivated on submerged fermentation using as substrate xylan, wheat bran, corn straw, corncob, and sugar cane bagasse. Corn straw and wheat bran show a good xylanase activity after 72 h of fermentation. A fungus identified as N. spinosa (strain P2D16) was cultivated on solid-state fermentation using as substrate source wheat bran, wheat bran plus sawdust, corn straw, corncob, cassava bran, and sugar cane bagasse. Wheat bran and corncobs show the better xylanase production after 72 h of fermentation. Both crude xylanases were characterized and a bacterial xylanase shows optimum pH for enzyme activity at 6.0, whereas a fungal xylanase has optimum pH at 5.0-5.5. They were stable in the pH range 5.0-10.0 and 5.5-8.5 for bacterial and fungal xylanase, respectively. The optimum temperatures were 55C and 60 A degrees C for bacterial and fungal xylanase, respectively, and they were thermally stable up to 50 A degrees C.

The influence of external ultrasound on the histologic architecture of the organic capsule around smooth silicone implants: Experimental study in rats

Background Capsular contracture is the main complication related to breast silicone implants, and its prevention remains a medical challenge. The authors present experimental research examining the effect of external ultrasound on the formation and contracture of peri-implant capsules.Methods In this study, 42 male Wistar rats had a 2-mm smooth surface implant placed in a dorsal submuscular pocket. They then were separated into ultrasound'' and control'' groups that received repeated external applications either with or without the ultrasound power on. Ultrasound applications were given three times a week for a period of 90 days. After that, both groups were housed under the same conditions with no application scheduled. Five animals of each group, killed at 30, 60, 90, and 180 days, had their implants removed along with the capsule, which received a special histologic preparation via annular sectioning that provided wide circumferential observation of the capsular tissue. Sections were stained with hematoxylin/eosin stain, Masson's trichrome stain, and Pricrosirius Red stain for regular microscopic evaluation under normal and polarized light.Results Histologic data showed that capsules from the ultrasound and control groups had statistically significant differences. Ultrasound application developed a capsular architecture similar to that shown within textured silicone implants, and its effect had an early definition with subsequent stabilization.Conclusion The authors conclude that early and repeated external ultrasound application enhances the thickness, cellular count, and vascularity of smooth silicone capsular tissue, whereas it diminishes the pattern of parallel orientation of collagen fibers.

Desempenho produtivo de alevinos de tilápia-do-nilo alimentados com levedura e derivados

O objetivo deste trabalho foi avaliar o desempenho produtivo e a composição químico-bromatológica do filé de tilápia-do-nilo alimentada com rações contendo levedura íntegra desidratada, levedura autolisada e parede celular. Rações práticas, isoprotéicas (32% de proteína digestível) e isoenergéticas (3.200 kcal de energia digestível por kg) suplementadas com levedura íntegra (1, 2 e 3%), levedura autolisada (1, 2 e 3%) e parede celular (0,1; 0,2 e 0,3%), e uma controle, sem ingredientes-teste, foram avaliadas. O delineamento experimental foi inteiramente casualizado, com dez tratamentos e quatro repetições. Peixes que receberam rações suplementadas com levedura e derivados apresentaram índice de desempenho produtivo superior ao controle. A suplementação da levedura autolisada proporcionou melhor resposta quanto ao ganho de peso (p<0,05). Não houve diferença na composição químico-bromatológica do filé, quando se compararam os contrastes entre totais de tratamento. A suplementação de levedura e derivados em rações para alevinos de tilápia-do-nilo melhora o desempenho produtivo, sem alterações na composição do filé, e entre os microingredientes avaliados, a levedura autolisada proporciona desempenho superior, quando utilizada entre 1,30 e 1,59%.

Evaluation of fermented milk containing probiotic on dental enamel and biofilm: In situ study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of subcutaneous and alveolar implantation surgical sites in the study of the biological properties of root-end filling endodontic materials

Objective: The aim of this study was to compare two methodologies used in the evaluation of tissue response to root-end filling materials in rats. Material and Methods: Forty rats were divided into 4 groups: in Groups I and II (control groups), empty polyethylene tubes were implanted in the extraction site and in the subcutaneous tissue, respectively; in Groups III and IV, polyethylene tubes filled with ProRoot MTA were implanted in the extraction site and in the subcutaneous tissue, respectively. The animals were killed 7 and 30 days after tube implantation, and the hemi-maxillas and the capsular subcutaneous tissue, both with the tubes, were removed. Specimens were processed and evaluated histomorphologicaly under light microscopy. The scores obtained were analyzed statistically by the Kruskal-Wallis test (p<0.05). Results: There were no statistically significant differences between the implantation methods (p=0.78033, p=0.72039). It was observed that the 30-day groups presented a more mature healing process due to smaller number of inflammatory cells. Conclusions: The present study showed no differences in tissue responses as far as the implantation site and the studied period were concerned. Alveolar socket implantation methodology represents an interesting method in the study of the biological properties of root-end filling endodontic materials due to the opportunity to evaluate bone tissue response.

Effect of Psidium cattleianum leaf extract on enamel demineralisation and dental biofilm composition in situ

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ultrastructure and cytochemistry of the pearl gland in Piper regnellii (Piperaceae)

Pearl glands are scattered throughout the lamina of developing leaves and rarely found on adult leaves of Piper regnellii (Piperaceae). The pearl gland is a bicellular secretory trichome composed of a short broad basal cell and a spatula-like, semiglobular apical cell. Four different stages of the pearl grand were determined during its ontogenesis: origin, pre-secretory, secretory and post-secretory. During the pre-secretory stage, mitochondria, ribosomes, dictyosomes, rough endoplasmic reticulum, and plastids with electron dense inclusions were present in the cytoplasm of the apical cell. During the secretory stage, the most remarkable characteristics of the apical cell are the proliferation of dictyosomes and their vesicles, rough endoplasmic reticulum, and modified plastids. At this stage, electron-dense oil drops occur in the plastids as well as scattered within the cytoplasm, proteins and polysaccharides are seen in the plastids, vesicles, and vacuoles. Only polysaccharides are present in the periplasmic space, wall cavities, and on the surface of the apical cell. The polysaccharides are one of the main components of the mucilagenous exudate that covers the developing leaf structures. The apical cell of the senescing trichomes undergoes a progressive degeneration of its cellular components, the plastids being the first organelles to undergo lysis.

Estruturas secretoras de mucilagem em Hibiscus pernambucensis Arruda (Malvaceae): distribuição, caracterização morfoanatômica e histoquímica

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

Coléteres dendróides em Alibertia sessilis (Vell.) K. Schum., uma espécie não-nodulada de Rubiaceae

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

Morfoanatomia comparada do talo de duas espécies de Parmotrema (Parmeliaceae, Ascomycota liquenizados) com rizinas dimórficas

Utilizando técnicas convencionais para estudos histológicos em microscopia de luz com auxílio de luz polarizada, se descreve e compara a anatomia do talo de duas espécies de Parmotrema, Parmotrema consors e Parmotrema cf. reparatum, com rizinas dimórficas e máculas efiguradas, antigamente incluídas em Canomaculina. Os dados obtidos neste estudo mostram que as duas espécies são anatomicamente distintas em relação às características do epicórtex, córtex superior e rizinas. Parmotrema cf. reparatum é anatomicamente similar ao grupo de Parmotrema com máculas reticulares (antigamente incluídas em Rimelia) previamente estudados. Os polissacarídeos típicos do epicórtex e córtex superior do grupo de espécies de Parmotrema com rizinas dimórficas possuem diferenciação histoquímica daqueles mencionados para o epicórtex e córtex superior do grupo de Parmotrema com máculas reticulares.