Purpose: Evaluation of the rheological, biological and therapeutic properties of a new topical formulation consisting of chitosan gel containing 1% silver sulfadiazine, as an alternative for the treatment of burn wounds. Methods: An experimental study was done with 21 Wistar rats divided into three groups. Group I was treated with chitosan gel without the antimicrobial, group II was treated with chitosan gel with 1% silver sulfadiazine and group III was treated with commercially available 1% silver sulfadiazine cream. Results: Due to its pseudoplastic characteristic and good bioadhesiveness, the chitosan gels showed a satisfactory retention time over the wounds. No statistical difference was found in the amount of drug released from the chitosan gel and commercially available cream, as well as in the healing time among the groups. Wounds treated with chitosan gel with silver sulfadiazine showed a higher fibroblast production and a better angiogenesis than in the other groups, which are important parameters on the evolution of the healing process. Conclusion: The topical use of chitosan gel in association with silver sulfadiazine ameliorated the neovascularization and inflammatory reaction in burn wounds. This new formulation showed advantageous rheological properties and efficient release of the drug. Key words: Chitosan. Silver Sulfadiazine. Gel. Wound Healing. Rats. RESUMOObjetivo: Avaliar as propriedades reológicas, biológicas e terapêuticas de uma nova formulação de uso tópico, a partir de um gel de quitosana, contendo sulfadiazina de prata a 1%, no tratamento de queimaduras. Métodos: Foi realizado estudo experimental com 21 ratos Wistar distribuídos em três grupos de sete animais. As queimaduras dos animais do grupo I foram tratadas com gel de quitosana sem antimicrobiano, o grupo II foi tratado com gel de quitosana contendo sulfadiazina de prata 1% e o grupo III foi tratado com creme de sulfadiazina de prata 1%, comumente utilizado no tratamento de queimados. Resultados: Devido às características pseudoplásticas e à boa bioadesividade, os géis de quitosana apresentaram um tempo de retenção satisfatório sobre as feridas. A liberação da sulfadiazina de prata, bem como o tempo de cicatrização, não foram estatisticamente diferentes. Feridas tratadas com o gel de quitosana contendo sulfadiazina de prata apresentaram uma maior produção de fibroblastos e uma melhor angiogênese, comparando-se com os outros grupos, fatores que indicaram uma maior evolução no processo de cicatrização. Conclusão: O uso tópico do gel de quitosana com sulfadiazina de prata a 1% melhorou a neovascularização e a reação inflamatória em queimaduras e essa nova formulação mostrou boas propriedades reológicas associadas a eficiente liberação do fármaco. Descritores: Quitosana. Sulfadiazina de prata. Cicatrização de Feridas. Ratos.

Water-insoluble glucan was isolated from the baker’s yeast Saccharomyces cerevisiae. The yeast cells were treated with alkali and the residue then with acid. Chemical and NMR (1D and 2D) analyses showed that a linear (1→3)-β-glucan was purified that was not contaminated with other carbohydrates, proteins or phenolic compounds. The effects of the glucan on wound healing were assessed in human venous ulcers by histopathological analysis after 30 days of topical treatment. (1→3)-β-glucan enhanced ulcer healing and increased epithelial hyperplasia, as well as increased inflammatory cells, angiogenesis and fibroblast proliferation. In one patient who had an ulcer that would not heal for over 15 years, glucan treatment caused a 67.8% decrease in the area of the ulcer. This is the first study to investigate the effects of (1→3)-β-glucan on venous ulcer healing in humans; our findings suggest that this glucan is a potential natural biological response modifier in wound healing.

The purpose of these studies was to evaluate chitosan films impregnated with silver sulfadiazine as potential wound dressings, based on their mechanical properties and the controlled-release phenomenon. The mechanical properties of such films were investigated under varying plasticizers (glycerol or sorbitol) concentrations, as well as in the presence of a crosslinking agent (formaldehyde). The drug release was also determined under such varying conditions, as well as using different thicknesses of film and drug concentrations. The results showed that the additives decreased the tensile strength of the chitosan films (except for sorbitol at 20% w/w), while at the same time remarkably enhancing the percentage elongation of the films. This elongation was especially pronounced in the case of glycerol. The type of plasticizer also influenced the release of silver sulfadiazine. Glycerol had a greater effect than sorbitol on the release rate, regardless of the amount used, probably due to leakage of this additive from the film, which leaves pores that enhance the water uptake of the film. As might be expected, increased concentrations of entrapped silver sulfadiazine yielded increasingly higher release rates. Decrease in thickness of the film also enhanced the release rate.

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Tamoxifen (TX), a drug used in the treatment of breast cancer, may cause hepatic changes in some patients. The consequences of its use on the liver tissues of rats with or without diabetes mellitus (DM) have not been fully explored. The purpose of this study was to evaluate the correlation between plasma hepatic enzyme levels and the presence of iron overload in the hepatic tissue of female Wistar rats with or without streptozotocin-induced DM and using TX. Female rats were studied in control groups: C-0 (non-drug users), C-V (sorbitol vehicle only) and C-TX (using TX). DM (diabetic non-drug users) and DM-TX (diabetics using TX) were the test groups. Sixty days after induced DM, blood samples were collected for glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST) alkaline phosphatase (ALP) and bilirubin measures. Hepatic fragments were processed and stained with hematoxylin and eosin, Masson's trichrome, Perls. The hepatic iron content was quantified by atomic absorption spectrometry. AST, ALT and ALP levels were significantly elevated in the DM and DM-TX groups, with unchanged bilirubin levels. Liver iron overload using Perls stain and atomic absorption spectrometry were observed exclusively in groups C-TX and DM-TX. There was positive correlation between AST, ALT and ALP levels and microscopic hepatic siderosis intensity in group DM-TX. In conclusion, TX administration is associated with liver siderosis in diabetic and non-diabetic rats. In addition, TX induced liver iron overload with unaltered hepatic function in non-diabetic rats and may be a useful tool for investigating the biological control of iron metabolism.

Purpose: To evaluate the effect of oxacillin bonded to magnetic nanoparticles in local infection model in rat. Methods: Twelve Wistar rats weighing 290±18g were randomly divided into four groups (n=6, each) and all rats had a magnet ring sutured on their right thighs. In the biodistribution group rats 0.1mL of 99m Tc-magnetite (0.66 MBq) was injected i.v and after 30 minutes, biodistribution of 99m Tc-magnetite was evaluated in right and left thighs. The other groups were inoculated with MRSA in each thigh muscles. Group 1 rats were injected i.v. with magnetite, group 2 with Magnetite + Oxacillin, group 3 with saline twice a day. After 24 hours samples of muscle secretion were harvested for microbiological analysis; muscle, lungs and kidneys for histology. Results: 99m Tc-magnetite uptake was three-fold higher in right thigh muscles (with external magnet) than in the left. In magnetite and oxacillin-magnetite groups, bacterial/CFU was significantly lower in thigh muscles than in saline-controls. The inflammatory reaction in muscles and lungs was significantly lower in oxacillin-magnetite group-rats than in other groups (p<0.001). Conclusion: This study confirms the potential antimicrobial activity of magnetic nanoparticles for Methicillin-Resistant S. aureus strains, which in addition to concentrate the antibiotic at the infection site, positively influenced the treatment.

Purpose: Based on studies that have attributed anti-inflammatory properties to statins, the aim of this work was to observe the effect of simvastatin in the attenuation of mucositis induced by methotrexate in the gastrointestinal tract in rats and its effects on cytokines. Methods: Twelve Wistar rats weighing 270±18 g were randomly distributed into two groups: methotrexate/saline (MTX/S n = 6) and methotrexate/simvastatin (MTX /SV n=6). In all animals, 3 mg / kg of methotrexate was injected subcutaneously for 3 consecutive days. In the MTX / SV simvastatin was administered orally one week before and during treatment with methotrexate. In the MTX/S, saline was administered at the same doses and schedules. We determined the plasma levels of TNF-α, IL-1β and IL-6 and the histological analysis by HE staining in segments of esophagus, stomach, duodenum, jejunum and colon. Results: The expression of TNF-α, IL-1β and IL-6 (14±91.7, 119.3±4 and 83.1±4, respectively) was lower in the MTX/SV group rats than in the MTX/S (171.3±16, 218. ±15 and 114.8±3, respectively). Histopathology showed that simvastatin reduced significantly (p<0.05) the damage induced by methotrexate in the mucosa of the esophagus, stomach, jejunum and colon. Conclusion: Simvastatin showed anti-inflammatory action in rats, suggesting potential clinical implication in the prevention or attenuation of mucositis induced by methotrexate.