3 resultados para Vesicle

em Universidade Estadual Paulista "Júlio de Mesquita Filho" (UNESP)


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This study reports an investigation of the pharmacological activity, cytotoxicity, and local effects of a liposomal formulation of the novel local anaesthetic ropivacaine (RVC) compared with its plain solution. RVC was encapsulated into large unilamellar vesicles (LUVs) composed of egg phosphatidylcholine, cholesterol and a-tocopherol (4:3:0.07, mole %). Particle size, partition coefficient determination and in-vitro release studies were used to characterize the encapsulation process. Cytotoxicity was evaluated by the tetrazolium reduction test using sciatic nerve Schwann cells in culture. Local anaesthetic activity was assessed by mouse sciatic and rat infraorbital nerve blockades. Histological analysis was performed to verify the myotoxic effects evoked by RVC formulations. Plain (RVCPLAIN) and liposomal RVC (RVCLUV) samples were tested at 0.125%, 0.25% and 0.5% concentrations. Vesicle size distribution showed liposomal populations of 370 and 130 nm (85 and 15%, respectively), without changes after RVC encapsulation. The partition coefficient value was 132 26 and in-vitro release assays revealed a decrease in RVC release rate (1.5 fold, P < 0.001) from liposomes. RVCLUV presented reduced cytotoxicity (P < 0.001) when compared with RVCPLAIN Treatment with RVCLUV increased the duration (P < 0.001) and intensity of the analgesic effects either on sciatic nerve blockade (1.4-1.6 fold) and infraorbital nerve blockade tests (1.5 fold), in relation to RVCPLAIN. Regarding histological analysis, no morphological tissue changes were detected in the area of injection and sparse inflammatory cells were observed in only one of the animals treated with RVCPLAIN or RVCLUV at 0.5%. Despite the differences between these preclinical studies and clinical conditions, we suggest RVCLUV as a potential new formulation, since RVC is a new and safe local anaesthetic agent.

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In the months of January 2001 and 2002, female cachara Pseudoplatystoma fasciatum were selected during their first and second gonadal maturation (2 years and 7 months old and 3 years and 7 months old, respectively) with an of oocyte diameter of 937.5 mum (82.5% with central nuclei and 17.5% with peripheral nuclei). Nine females in first maturation received two doses of carp pituitary extract (CPE), 0.5 mg/kg and 5.0 mg/kg; seven received two doses of human chorionic gonadotropin (hCG), 5 and 10 IU/g; five received doses of 0.5 CPE mg/kg and 5 hCG IU/g (CPE+hCG); and four received 0.9% saline (saline). Nine females from CPE and seven from hCG presented oocytes with the same diameter at the moment of oocyte release (100% with germinal vesicle breakdown and fertilization rate of 53.44 +/- 18.3 and 54.81 +/- 11.8%; larvae number of 165,330 +/- 94.1 and 158,570 +/- 20.6, respectively). The five females from CPE+hCG did not respond to the hormonal treatment. The four females from the saline group did not ovulate. In January 2002, 6 of 15 selected females that were going through the second reproductive cycle received CPE (five received hCG and four received saline), showing oocyte diameters similar to the ones in the first maturation. At stripping, CPE females had an oocyte diameter of 1062.5 mum (the hCG females had oocyte diameters ranging from 937.5 to 1125.0 mum; fertilization rates of 56.08 +/- 30.9 and 81.90 +/- 17.3%; 364,547 +/- 244 and 633,129 +/- 190, larvae, respectively). The fertilization rates and larvae number were higher in the second gonad maturation, both for CPE and hCG. (C) 2004 Elsevier B.V. All rights reserved.

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Based on the reports of unsuccessful ovulation in pacu (Piaractus mesopotamicus) by fish farmers and researchers undertaking artificial reproduction programs, we evaluated the use of prostaglandin F (PGF) to improve pacu ovulation. This study was conducted during two spawning seasons (2009/2010 and 2010/2011) with two samplings in the first season and one sampling in the second season. A total of 45 females was sampled in this study. The control group was injected with carp pituitary extract (crude extract, 6 mg/kg), and the treatment group received PGF (2 mL per fish in the 2009/2010 season and 5 mL per fish in the 2010/2011 season) in addition to the crude extract. In both seasons, 100% (N = 4, 2009/2010 first sampling; N = 5, 2009/2010 second sampling; and N = 3, 2010/2011) of the PGF-treated fish spawned. In contrast, 53.0% (N = 9) and 83.3% (N = 10) of the control fish spawned in the first and second samplings of the 2009/2010 season, respectively, and only 25.0% (N = 1) spawned in the 2010/2011 season. Fecundity, fertility, and hatching rates did not differ (P > 0.05) between the treated and control fish. Based on oocyte volume frequency analysis, ovaries of the control fish had more (P < 0.05) vitellogenic oocytes with germinal vesicle breakdown that remained unovulated after spawning, whereas more (P < 0.05) of previtellogenic oocytes were present in the ovaries of the PGF-treated fish. In conclusion, administration of exogenous prostaglandin may improve the outcome of hormonally induced spawning in tropical migratory fish. (C) 2012 Elsevier B.V. All rights reserved.