Red blood cells (RBCs) are exposed to both external and internal sources of oxidants that challenge their integrity and compromise their physiological function and supply of oxygen to tissues. Autoxidation of oxyhemoglobin is the main source of endogenous RBC oxidant production, yielding superoxide radical and then hydrogen peroxide. In addition, potent oxidants from other blood cells and the surrounding endothelium can reach the RBCs. Abundant and efficient enzymatic systems and low molecular weight antioxidants prevent most of the damage to the RBCs and also position the RBCs as a sink of vascular oxidants that allow the body to maintain a healthy circulatory system. Among the antioxidant enzymes, the thiol-dependent peroxidase peroxiredoxin 2, highly abundant in RBCs, is essential to keep the redox balance. A great part of the RBC antioxidant activity is supported by an active glucose metabolism that provides reducing power in the form of NADPH via the pentose phosphate pathway. There are several RBC defects and situations that generate oxidative stress conditions where the defense mechanisms are overwhelmed, and these include glucose-6-phosphate dehydrogenase deficiencies (favism), hemoglobinopathies like sickle cell disease and thalassemia, as well as packed RBCs for transfusion that suffer from storage lesions. These oxidative stress-associated pathologies of the RBCs underline the relevance of redox balance in these anucleated cells that lack a mechanism of DNA-inducible antioxidant response and rely on a complex and robust network of antioxidant systems.

SummaryThis research presents the first anatomical description of the tongue and lingual papillae of the mountain lion (puma). The tongues of three adult male pumas were used in this study. The tongues were dissected and studied firstly by gross and stereomicroscopy. Samples of each part were processed by study with scanning electron microscopy. The margins of the lingual apex were surrounded by numerous filiform papillae, which had a bulky papillary body and a bifurcated tip. On the dorsal surface of the lingual apex, filiform papillae were remarkably pointed and had many secondary projections, which emerged from the base of the main papilla. In the rostral half of the lingual body, filiform papillae were longer, cylindrical and had blunt tips. On the caudal half of the lingual body, filiform papillae gave place to conical ones exhibiting a pointed tip. The fungiform papillae were scattered on the whole dorsal surface of the tongue.On each lateral half of the tongue, four circumvallate papillae were observed and each circumvallate papilla was surrounded by thick and horseshoe-like annular pad, which were composed by pointed conical papillae on the caudal border of the lingual body.The dorsal surface of the circumvallate papilla was covered by many finger-like protrusion, and the tip of each protrusion had a central orifice. Anatomical distribution of lingual papillae was different to other carnivores and represents the adaptation to the feeding habits of this mammal. General morphology of the lingual structures was similar to those of the tiger.

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