Evaluation of the Larval Therapy in the Healing Process of Infected Wounds with Pseudomonas Aeruginosa in Rabbits

Introduction. During the last two decades the larval therapy has reemerged as a safe and reliable alternative for the healing of cutaneous ulcers that do not respond to the conventional treatments. Objective. To evaluate the use of the larvae of Lucilia sericata as a treatment for infected wounds with Pseudomonas aeruginosa in an animal model. Materials and methods. Twelve rabbits were randomly distributed in 3 groups: the first group was treated with larval therapy; the second was treated with antibiotics therapy and to the third no treatment was applied, therefore was established as a control group. To each animal a wound was artificially induced, and then a suspension of P. aeruginosa was inoculated into the lesion. Finally, every rabbit was evaluated until the infection development was recognized and treatment was set up for the first two groups according with the protocols mentioned above. Macroscopic evaluation of the wounds was based on the presence of edema, exudates, bad odor, inflammation around the wound and the presence of granulation tissue. The healing process was evaluated by monitoring histological changes in the dermal tissue. Results. Differences in the time required for wound healing were observed between the first group treated with larval therapy (10 days) and the second group treated with conventional antibiotics therapy (20 days). Conclusion. The L. sericata larva is and efficient tool as a therapy for infected wounds with P. aeruginosa.

Efectos de la ventilación mecánica con heliox en niños y adolescentes con patología bronquial obstructiva

Evaluar si el Heliox reduce la resistencia en la vía aérea en niños y adolescentes con patología bronquial obstructiva que requieren ventilación mecánica. Materiales y Métodos: Estudio prospectivo observacional descriptivo en niños y adolescentes con patología bronquial obstructiva y ventilación mecánica con Fi02 ≤ 0,5. Medición de variables: resistencia, presión pico, presión media de la vía aérea, presión meseta, volumen corriente, autoPEEP, distensibilidad, PetCO2, ventilación de espacio muerto antes de inicio de heliox y a los 30 minutos, 2, 4, 6, 12, 18 y 24 horas y diariamente hasta suspenderlo por extubación o FiO2 > 0,5. Resultados: Resultados parciales, incluyó 9 pacientes encontrando descenso significativo de resistencia espiratoria a los 30 minutos (51,2 vs 32,3; p=0,0008 ), 2 horas ( 51,2 vs 33,4; p=0,0019) y 4 horas (51,2 vs 30,7; p=0,0012) así como de la resistencia inspiratoria a la hora 2 (48,6 vs 36,2; p = 0,013) y hora 4 (48,6 vs 30 ; p=0,004). Se observó tendencia al descenso de la PetCO2 que no fue significativa (52,3 vs 34,3: p=0,06). No se evidenció cambios en las variables; autoPEEP, presión pico, presión media de la vía aérea, distensibilidad, ventilación de espacio muerto, presión meseta y volumen corriente antes y después del inicio del Heliox. Conclusión: La ventilación mecánica con Heliox en niños con patología bronquial obstructiva parece ser que reduce de manera significativa la resistencia de la vía aérea, con tendencia al descenso de la PetC02. Se necesitan estudios prospectivos al menos observacionales analíticos que corroboren estos hallazgos.

Identification, characterization and antigenicity of the Plasmodium vivax rhoptry neck protein 1 (PvRON1)

Background: Plasmodium vivax malaria remains a major health problem in tropical and sub-tropical regions worldwide. Several rhoptry proteins which are important for interaction with and/or invasion of red blood cells, such as PfRONs, Pf92, Pf38, Pf12 and Pf34, have been described during the last few years and are being considered as potential anti-malarial vaccine candidates. This study describes the identification and characterization of the P. vivax rhoptry neck protein 1 (PvRON1) and examine its antigenicity in natural P. vivax infections. Methods: The PvRON1 encoding gene, which is homologous to that encoding the P. falciparum apical sushi protein (ASP) according to the plasmoDB database, was selected as our study target. The pvron1 gene transcription was evaluated by RT-PCR using RNA obtained from the P. vivax VCG-1 strain. Two peptides derived from the deduced P. vivax Sal-I PvRON1 sequence were synthesized and inoculated in rabbits for obtaining anti-PvRON1 antibodies which were used to confirm the protein expression in VCG-1 strain schizonts along with its association with detergent-resistant microdomains (DRMs) by Western blot, and its localization by immunofluorescence assays. The antigenicity of the PvRON1 protein was assessed using human sera from individuals previously exposed to P. vivax malaria by ELISA. Results: In the P. vivax VCG-1 strain, RON1 is a 764 amino acid-long protein. In silico analysis has revealed that PvRON1 shares essential characteristics with different antigens involved in invasion, such as the presence of a secretory signal, a GPI-anchor sequence and a putative sushi domain. The PvRON1 protein is expressed in parasite's schizont stage, localized in rhoptry necks and it is associated with DRMs. Recombinant protein recognition by human sera indicates that this antigen can trigger an immune response during a natural infection with P. vivax. Conclusions: This study shows the identification and characterization of the P. vivax rhoptry neck protein 1 in the VCG-1 strain. Taking into account that PvRON1 shares several important characteristics with other Plasmodium antigens that play a functional role during RBC invasion and, as shown here, it is antigenic, it could be considered as a good vaccine candidate. Further studies aimed at assessing its immunogenicity and protection-inducing ability in the Aotus monkey model are thus recommended.