A Global Overview of Exposure Levels and Biological Effects of Trace Elements in Penguins.

Trace elements are chemical contaminants that can be present almost anywhere on the planet. The study of trace elements in biotic matrices is a topic of great relevance for the implications that it can have on wildlife and human health. Penguins are very useful, since they live exclusively in the Southern Hemisphere and represent about 90% of the biomass of birds of the Southern Ocean.

Total persistence of thyroglossal duct with direct communication between cyst and foramen caecum.

During embryonic development the thyroid gland migrates through the thyroglossal duct from the pharyngeal endoderm to the anterior cervical region. The final step in this process is the total obliteration of the thyroglossal duct. A case is presented of a patient with a thyroglossal cyst together with a complete failure of the obliteration of the duct, which caused regurgitations of mucopurulent material after the expression of the cyst.