Neospora caninum: infection induces high lysosomal activity.

Neospora caninum is a protozoan that causes abortion in cattle and neuromuscular lesions in dogs, making it an important target of veterinary medicine. Lysosomes are cellular organelles responsible for important biological functions as cellular defense mechanisms. The aim of this work was to evaluate the lysosomal stability of rat gliocytes infected in vitro with N. caninum. Rat glial cultures were infected at a ratio of 1:1 (cell/parasite). The enzymatic activity of acid phosphatase (orthophosphoric-monoester phosphohydrolase, EC 3.1.3.2) was assayed in the medium of control and infected cell cultures. The activity observed at 24h of incubation was 0.4±0.08mU/mg/min for control cells and 1.3±0.5mU/mg/min for infected cells. After 72h, control and infected cells exhibited activities of 1.3±0.5 and 4.1±0.9mU/mg/min, respectively. These results suggested that lysosomal compartment plays an important role in the mechanisms of cellular infection by N. caninum.

Papel do Nácar como agente osteogênico na recuperação de lesões periodontais em cães / Role of nacre as osteogenic agent in the recuperation of dog periodontal lesions

A última década caracterizou-se pela busca de novos biomateriais usados como indutores osteogênicos. O nácar (madrepérola) foi descrito como um biomaterial que pode iniciar a formação óssea por osteoblastos humanos, in vivo e in vitro. Neste trabalho testou-se o efeito do pó de nácar (tamanho das partículas entre 50 a 150 mm) extraídas da bivalve Mytella falcata, na reconstrução do osso alveolar de maxilares de cães. Depois de anestesiados, dois cães sadios foram submetidos à extração dos terceiros premolares esquerdos e direitos e também dos quartos premolares superiores de ambos os lados. As lesões foram tratadas separadamente por sangue autógeno, gelatina, pó de nácar e nácar misturado à gelatina. Após seis meses os mesmos cães foram uma vez mais anestesiados e então sacrificados. Amostras do osso alveolar lesado foram estudadas histologicamente. Os resultados mostraram que o pó de nácar in natura é um biomaterial com fracas propriedades osteogênicas e pouco atua na recomposição do ambiente que caracteriza o desenvolvimento ósseo. Este estudo não confirma observações anteriores que consideram o nácar como um bom indutor da osteogênese.

Host/parasite relationship in the in vitro infection of rat gliocytes by Neospora caninum: evaluation of cell respiration.

Neospora caninum is a protozoon that causes abortion in cattle and neuromuscular lesions in dogs, with the formation of cysts mainly in the central nervous system. Since N. caninum is an intracellular parasite with tropism for the cells of nervous system, this study evaluated the respiratory metabolism of glial cells infected by this* parasite. Glial cultures obtained from the cerebral cortex of newborn rats were kept in DMEM enriched with 10% fetal bovine serum, 1 mM pyruvic acid and 2 mM of L-glutamine. They were infected at a ratio of approximately 1:1 (cell/parasite). Oxygen consumption was evaluated by polarography in the non infected and N. caninum infected groups, 24 and 72 h following infection. Glial cell respiration after 24 and 72 h was 307.2 +/- 34.7 and 308.9 +/- 64.1 microL of oxygen per mug of total protein per minute, and 566.2 +/- 54.6 and 579 +/- 117.5 microL O2/microg of total protein/minute in the control and infected groups, respectively. These results show that N. caninum does not interfere with glial respiration in vitro.