Mercury and selenium concentrations, and selenium:mercury molar ratios in small cetaceans taken off St. Vincent, West Indies.

This study measured the concentration of total mercury (THg) and selenium (Se), and calculated the Se:Hg molar ratios in the muscle, blubber, liver, and kidney of small cetaceans (false killer whale, Pseudorca crassidens; killer whale, Orcinus orca; Risso's dolphin, Grampus griseus; short-finned pilot whale, Globicephala macrorhynchus; and dolphins of the genus Stenella) taken for human consumption off St. Vincent, West Indies. Overall, 122 samples were analyzed; mean THg concentrations (µg/g dry weight) were highest in the liver (730), followed by the kidney (274), muscle (76.4), and blubber (4.57). To explain variability in muscle THg concentrations, carbon (δ13C) and nitrogen (δ15N) stable isotope ratios were analyzed to explore differences in dietary carbon source and relative trophic position, respectively, among species. There was no relationship between δ15N and THg concentration, but there was a positive relationship between δ13C and THg concentration. On average for each species, the Se:Hg molar ratios were >1 in blubber and <1 in muscle. All liver samples and the majority of kidney, muscle, and blubber samples exceeded the FAO/WHO human consumption advisory level of 1 µg/g wet weight. Based on our estimations, consuming only 6.6 g of muscle a week would exceed the MeHg provisional tolerable weekly intake of 1.6 µg MeHg/kg body weight/week for a 60 kg person. Given the high THg concentration in these cetaceans and the frequency at which these tissues are consumed, this is a potential human health issue that warrants further investigation.

Chronic feeding with 3% dried raw blueberries (V. corymbosum) reduces apomorphine-induced rotations and striatal dopaminergic loss in hemiparkinsonian rats.

Blueberries (BB) are rich in antioxidant polyphenols, and their intake could prevent Parkinson's disease (PD). Here we assessed whether rats chronically fed dried raw BB develop resistance to dopaminergic denervation and motor disorders caused by unilateral intrastriatal injection of 6-hydroxydopamine (6-OHDA), a dopaminergic neurotoxin acting mainly by inducing oxidative stress. Male rats were fed either with LabDiet® alone or supplemented with 3% lyophilized raw BB for 2 weeks before and 3 weeks after injecting 6-OHDA (day 0) or vehicle (mock lesion) into the right striatum. The cylinder test was performed on days -14, -7, -1, +7, +14, and +21; the percentage of ipsilateral forepaw (IF) use asymmetry was determined by counting the wall contacts made with either forepaw or with both. Apomorphine (0.25 mg/kg, s.c.)-induced rotation was performed on days -1, +7, +14, and +21. Full contralateral rotations were counted in 3-min periods, every 15 min, up to 90 min. Striatal slices were immunostained for tyrosine hydroxylase (TH) and the ionized calcium-binding protein-1 adapter (Iba1) [immunoreactive area or microglia count in right striatum expressed as % of the left striatum]. Antioxidants in BB methanolic extracts neutralized the free radical 2,2-diphenyl-1-picrylhydrazyl in a concentration-dependent manner. Anthocyanins have been reported as the most abundant polyphenols in BB. Using the pH differential method, the total anthocyanin content (malvidin-3-glucoside equivalents) in raw BB averaged 21.04 mg/g dry weight. The range of anthocyanin intake by rats throughout the study varied from 37.7 to 72.2 mg/kg body weight. The time and food type factors, as well as their interaction were significant according to two-way RM-ANOVA in both the apomorphine-induced rotations and the cylinder test. Compared with LabDiet® alone, chronic supplementation with 3% dried raw BB decreased apomorphine-induced rotations on days +14 and +21 (p < 0.001) and produced a 46% reduction in total rotations post-surgery (p < 0.05), but only caused a partial, non-significant, decrease of IF asymmetry. BB supplementation reduced TH loss in the striatum (p < 0.05) but did not attenuate the increase of Iba1+ microglia. The consumption of 3% dried raw blueberries attenuates dopaminergic denervation and partially reverses motor disorders in the 6-OHDA-induced PD model in rats. The phytochemicals of raw blueberries that contribute to the observed neuroprotective effect are yet to be identified.

Epidemia por virus dengue-2 en Salta, Argentina, 1998 / Outbreak of Dengue-2 virus in Salta, Argentina, 1988

La reemergencia del dengue (DEN) en la Argentina fue primero detectada en Salta en 1997. Se determinó por serología y PCR que el virus DEN-2 estuvo asociado a casos esporádicos y transmisión autóctona. La implementación de un sistema de vigilancia permitió la detección de un brote en esa área varios meses después. Se diagnosticaron en total 378 casos de DEN de 646 (58%) estudiados por laboratorio. Los casos se distribuyeron en 10 localidades de esta provincia entre el 3 de enero y el 31 de mayo de 1998. El virus DEN-2 se recuperó en un caso por aislamiento y en 4 por PCR de pacientes provenientes de las localidades de Orán y Embarcación. Los hombres y las mujeres fueron afectados en una tasa similar (1:1), con un porcentaje de adultos (82.5%) casi cinco veces superior al de niños menores de 15 años (17.5%). Clínicamente, todos los casos correspondieron a DEN clásico. Esta es la primera vez que se diagnostica por laboratorio una epidemia de DEN en la Argentina y también la primera vez que se aisló el virus DEN en este país.