Oral immunostimulation of the oyster Ostrea edulis: Impacts on the parasite Bonamia ostreae.

Bioactive compounds were orally administered to the native European oyster Ostrea edulis to evaluate the immune response and the progression of infection of the protozoan parasite Bonamia ostreae. The immunostimulants lipopolysaccharide and zymosan directly administrated to the water column induced an increase in lysozyme activity and the percentage of granulocytes in naïve oysters over a period of 7 days. In another set of experiments, zymosan and curdlan were microencapsulated in alginate and also administered to the water column to naïve and B. ostreae infected O. edulis. Oyster mortality, prevalence and intensity of infection and several immune parameters were evaluated up to 28 days post-administration. Lysozyme activity, nitric oxide production and the expression of galectin, lysozyme and superoxide dismutase increased after 24 h in both infected and uninfected oysters. Zymosan immunostimulated oysters displayed a decrease in the prevalence of B. ostreae infection not attributed to mortalities but which could be associated to the enhanced ability of immunostimulants to evoke an enhanced immune response in the oysters and reduce infection.

One year oral Toxicity of D-004, a lipid extract from Roystonea regia fruits, in Sprague Dawley rats.

D-004, a lipid extract of royal palm (Roystonea regia) fruits that contains a reproducible mixture of fatty acids, has been shown to prevent testosterone and phenylephrine-induced prostate hyperplasia in rodents. This study investigated the long-term oral toxicity of D-004 in rats. Rats from both sexes were randomized into four groups (20 rats sex/group): a control and three treated with D-004 (800, 1500 or 2000 mg/kg/day, respectively). At study completion, rats were sacrificed under anaesthesia. Determinations of blood biochemical and haematological parameters and organ weight were done. Also, necropsy and histopathological studies were performed. Four of 160 rats died before study completion. No clinical signs of toxicity were observed throughout the study. Food and water consumption, bodyweight, blood biochemical and haematological parameters, organ weight ratios and histopathological findings were similar in control and treated groups. The histological lesions found in treated animals are commonly present in this specie and strain according to literature and our historical data. In conclusion, long-term (12 months) oral treatment of rats with D-004 (800-2000 mg/kg/day) did not show evidences of D-004-related toxicity under our conditions. The highest dose tested (2000 mg/kg) was a no-observed adverse effect level in this study.

Ascorbic acid protects against levodopa-induced neurotoxicity on a catecholamine-rich human neuroblastoma cell line.

Levodopa, at concentrations of 0.25 x 10(-4) M or larger, is toxic for the human neuroblastoma cell NB69. Toxicity is associated with high levels of quinones, increased activity of complex II-III, and lack of changes of complex I of the mitochondrial respiratory chain. Deprenyl, which does not alter the production of quinones, has a partial protective effect. Tocopherol, 23 or 115 x 10(-6) M, lacks significant preventive effect on levodopa toxicity, but ascorbic acid, 10(-3) M, prevents levodopa toxicity and quinone formation. Deprenyl, 10(-4) M, provides additional protection in cultures treated with levodopa and ascorbic acid. Our results indicate that ascorbic acid and deprenyl prevent levodopa neurotoxicity by unrelated mechanisms. Both compounds should be considered as complementary drugs to test for slowing the progression of Parkinson's disease.