Polyester microparticles as a vaccine delivery system for brucellosis: influence of the polymer on release, phagocytosis and toxicity.

Microparticles, containing an antigenic complex from Brucella ovis (HS), were evaluated for vaccine purposes against brucellosis. They were prepared by the double emulsion solvent evaporation method using two different polyesters, poly-lactide-co-glycolide acid (75:25; RG 756) and poly-epsilon-caprolactone. The encapsulation efficiency and release of HS from the microparticles, their capacity to be phagocytosed and also their toxicity on murine monocytes J774.2 were investigated. Both polymers lead to smooth and spherical sub-5 microm particles, with approximately 30% of the antigen initial dose encapsulated. SDS-PAGE and immunoblot of extracted antigens confirmed that the apparent molecular weight and antigenicity remained unaltered after the encapsulation procedure. However, the in vitro release of the antigens differed among them. The release profile for PLGA microparticles was continuous, whereas PEC ones released the antigens in a triphasic release pattern. Phagocytosis was clearly influenced by the hydrophobicity of the polymer, increasing in the case of PEC microparticles. Toxicity assay showed that both types of microparticles induced similar levels of mitochondrial damage. In conclusion, HS-PEC microparticles could be used as an effective vaccine against brucellosis, as the antigen is released in boosters and they are greatly phagocytosed by macrophages.

Development of microparticles prepared by spray-drying as a vaccine delivery system against brucellosis.

The antigenic extract Hot Saline from Brucella ovis was microencapsulated by the spray-drying technique with different polyesters (poly-lactide-co-glycolide RG502H [PLGA], and blends with poly- epsilon -caprolactone [PEC]) in order to obtain microparticles smaller than 5 microm. Microparticles were tested for encapsulation efficiency, release studies, acidification of the in vitro release medium, and in vitro J744-macrophage experiments (phagocytosis and toxicity of the preparations) to determine the optimal formulation for vaccination purposes. Formulation containing no PCL showed the highest encapsulation efficiency, although the differences were not significant. The in vitro release kinetics were characterized by a high burst effect after 1 h of incubation, followed by a slow and continuous release. For the formulation based on PLGA, the pH of the medium during release dropped from 7.4 to 3.5 while the presence of PEC attenuated the pH drop. All formulations showed light toxicity by the MTT assay, but differences were observed in terms of phagocytosis, as particles prepared with PEC showed the higher uptake by J744-macrophages and cell respiratory burst, determined by oxygen peroxide release. All these characteristics suggest that the microparticulated antigenic formulation containing the higher ratio of PEC is susceptible to be used in animal vaccination studies.

Influence of the co-encapsulation of different excipients on the properties of polyester microparticle-based vaccine against brucellosis.

This work evaluates the influence of different pharmaceutical auxiliaries (Pluronic F68, polyvinylpyrrolidone [PVP] or Tween 20), when mixed with an antigenic extract from Brucella ovis (hot saline; HS), on the characteristics of the resulting poly(epsilon-caprolactone) (PEC) and poly(lactide-co-glycolide) (PLGA) microparticles. In all cases, PEC microparticles were smaller than PLGA ones. Concerning the HS loading, PLGA microparticles were highly dependent on the type of the excipient used, whereas all the PEC formulations displayed similar encapsulation efficiencies. For both types of microparticles, the presence of PVP induced a burst release effect. On the contrary, the use of Tween 20 or Pluronic F68 dramatically modified this profile. For PLGA-Tween 20 and PEC-Pluronic F68 microparticles, the HS was released in a pulsatil way during the first 7 days followed by a continuous release for at least 3 weeks. The antigenicity of the HS components was kept in all cases. Phagocytosis by murine monocytes showed a clear difference based just on the hydrophobicity of the polymer, being PEC microparticles better engulfed. Cell activation quantified by the release of H2O2 did not showed major differences between batches, however, microparticles of PEC and Pluronic F68 induced the highest nitric oxide production. Together, these results confirm the advantageous qualities of the "HS-PEC-Pluronic F68 microparticles" as favorable candidate for vaccine purposes against brucellosis.

Planktonic primary production in a tidally influenced mangrove forest on the Pacific coast of Costa Rica.

The seasonal variation of planktonic primary productivity was measured during one year in the main channel in the interior part of the mangrove forest of the Estero de Morales (Estero de Punta Morales), a mangrove system located in the Golfo de Nicoya at the Pacific coast of Costa Rica. Samples were incubated at the surface, 0.5 m and 1.0 m depth and the "light and dark bottle technique" was employed. The annual gross primary productivity (PPg) was 457 and the net primary productivity (PPn) was 278 g C m(-2) a(-1). Daily PPg ranged from 0.29 to 3.88 and PPn from 0.12 to 2.76 g C m(-2) d(-1). The highest rates observed in May and September were due to red tide blooms. The seasonal variation of primary productivity inside the mangrove forest depends closely on the PP in the adjacent area of the upper Golfo de Nicoya. Obviously the PP was light-limited since the compensation depth in the ebb current was found at only 1 m depth. In the flood current it was somewhat deeper. The planktonic primary productivity inside the mangrove forest was completely restricted to the open channels. A simultaneous measurement demonstrated that PPn of the phytoplankton could not take place under the canopy of the mangroves. Additional studies on the time course of the oxygen concentration in the mouth of the main channel over 24 hrs demonstrated a relation between the O2 and the tidal curves. The ebb current had always lower O2 concentrations than the flood current, regardless of the time of the day. The difference to the foregoing high tide, however, was much smaller when the low tide occurred during the day. This indicates that under the canopy the net primary production and hence O2 liberation of the attached macro- and microalgae, together with the high PPn of the phytoplankton in the channels, helped the oxygen concentration not to decrease as far as during the night. Nevertheless it shows that the consumtion of organic material in the submersed part of the mangrove forest exceeds always its production.

[Controlled liberation of active principles by means of new galenic formulations]. / Liberación controlada de principios activos mediante el empleo de formulaciones galénicas.

Drugs inside a conventional galenic form are distributed between specific biological targets and other anatomical tissues. With the aim to obtain a more rational and a better therapeutic, one of the most promising possibilities by using the concept of vectorization: association of an active principle to an appropriate vector with the object to increase its action efficiency and efficacy. By this means, they do not just increase the affinity of the drug to the target but also active principle gets protected from a potentially hostile environment (hydrolytic enzymes, acid pH, etc.). The success in the extension of the applications of the vectorización depends more and more of an appropriate design, for what the fundamental objective of this revision will be the one of presenting the general characteristics and some of the current applications in these new galenic forms.

A Importância da atuação do odontolegista no processo de identificação humana de vítimas de desastre aéreo / The Importance of the dental expert´s role in human identification process of air disaster victms

O campo de atuação do Odontolegista abrange desde perícias em foro administrativo, criminal, cível até a identificação humana. O papel deste profissional na identificação é de extrema importância em casos de acidentes de massa, destacando-se o desastre aéreo que, por sua dimensão, resulta em cadáveres carbonizados, fragmentados e, muitas vezes, em estado avançado de decomposição. Diante dessas circunstâncias, o método de comparação odontológica torna-se imprescindível, sendo ainda uma técnica de fácil execução, não onerosa, eficaz e rápida diante da necessidade de grande quantidade de identificações em um curto espaço de tempo. Objetivo: Pelo exposto, o presente estudo tem por objetivo analisar o perfil profissional bem como a atuação do odontolegista no contexto de atividades de identificação humana de vítimas de desastre aéreo ocorridos na última década, no Brasil. Material e método: A metodologia utilizada envolveu revisão de literatura e, em seguida, pesquisa de campo, com realização de entrevistas com três cirurgiões-dentistas que participaram da identificação de vítimas em desastres aéreos ocorridos no Brasil e posterior análise das mesmas. Resultados: Os resultados apontam para uma confluência entre as opiniões dos entrevistados quanto a: importância do odontolegista e dos registros odontológicos. Conclusão: Concluiu-se que a atuação do odontolegista é fundamental no processo de identificação de vítimas de acidente aéreo; que as maiores dificuldades encontradas na identificação dessas vítimas são o fato da maioria delas estarem carbonizadas e/ou fragmentadas e pela ausência de material antemortem para realização de confronto odontológico; e que o Brasil deveria preparar-se melhor para atuar com eficiência diante dessa modalidade de desastre de massa.

The dental expert´s range from expertise in administrative, criminal or civil courts to human identification. The role of this professional in identification is extremely important in cases of mass casualties, especially concerning the air crash, which, in dimension, results in charred bodies, or fragmented ones and often in an advanced state of decomposition. Under these circumstances, the method of dental comparison becomes essential, and also a simple technique, not expensive, quick and effective due to the need of a large number of identifications in a short time. Objective: Given the above, this study aims to examine the professional profile as well as the role of dental expert?s in the context of activities in human identification of air disaster victims occurred in the last decade in Brazil. Material and method: The methodology consisted in literature review and, then, research, involving interviews with three dentists that participated in the identification of air disaster victims that occurred in Brazil, and further analysis of their reports. Results: The results point out to a convergence between the views of respondents regarding: the importance of the dental expert?s and of the dental records. Conclusion: It was possible to conclude that the performance of the dental expert?s is crucial in the process of identification of airplane crash victims; that the greatest difficulties in identifying these victims are the fact that most of them were burned and / or fragmented and the lack of antemortem material to conduct dental confrontation; and that Brazil should be better prepared to act efficiently on this kind of mass disaster.

A Brucella ovis antigenic complex bearing poly-epsilon-caprolactone microparticles confer protection against experimental brucellosis in mice.

A hot saline antigenic extract (HS) from Brucella ovis was encapsulated in poly-epsilon-caprolactone microparticles (PEC), and tested as a vaccine against B. ovis and B. abortus infections in mice. Subcutaneous but not oral administration in BALB/c mice of the HS-PEC induced high amounts of IFN-gamma and IL-2 but low quantities of IL-4 suggesting a combined Th1/Th2 cellular immune response. The vaccine administered either subcutaneously or orally protected mice against B. ovis infection. Such protection was similar to that provided by the reference living attenuated B. melitensis Rev. 1 vaccine. By contrast, only the subcutaneous vaccination with HS-PEC was as effective as Rev. 1 in conferring protection against B. abortus infection. The use of free HS or empty PEC microparticles did not produce any protective effect.