Metals – impact and implications

Impact of metal in vitro administration on rat tissue oxygen consumption is referred in the first part. Toxicological implications of in vivo metal administration to rats and the study of potential penetration of metal into the rat brain, which may eventually result in oxygen radical production are presented in second part

Methodological limitations of counting total leukocytes and thrombocytes in reptiles (Amazon turtle, Podocnemis expansa): an analysis and discussion Limitações metodológicas de contagens de leucócitos e trombócitos totais em répteis (tartaruga da Amazônia, Podocnemis expansa): uma análise e discussão

The aim of this paper is to compare three different methods for counting white blood cells [WBC] (Natt and Herrick method, estimation with 1,000 and 2,000 erythrocytes) and three methods for counting total thrombocytes [TT] (Wojtaszek method, estimation with 1,000 and 2,000 erythrocytes) in a South American freshwater turtle species, Podocnemis expansa, Schweigger 1812 (Reptilia, Pelomedusidae). Direct WBC counts using the Natt and Herrick method showed limitations, which are discussed here. The WBC and TT counts using 1,000 erythrocytes from blood smears are not recommended for Amazon turtles nor other reptilian species, since wide variation in counts can be observed. Estimation methods for determining WBC and TT based on 2,000 erythrocytes of blood smears were most acceptable because they allow a differentiation between leukocytes and thrombocytes and also had a smaller variation. The methods investigated here for the Amazon turtle, which have been widely used in other reptile species, provided evidence that the most acceptable method is not that of using diluted stains and a hemocytometer.<br>O objetivo deste estudo foi comparar três diferentes métodos para contar leucócitos totais [LT] (método de Natt & Herrick, de estimação em 1000 e 2000 eritrócitos) e três métodos para contar trombócitos totais [TT] ( método de Wojtaszek, de estimação em 1000 e 2000 eritrócitos) em uma espécie de tartaruga de água doce da América do Sul, Podocnemis expansa, Schweigger 1812 (Reptilia, Pelomedusidae). As contagens diretas de LT usando o método de Natt & Herrick mostraram limitações que são aqui discutidas. As contagens de LT e TT usando estimativa em 1000 eritrócitos na extensão sanguínea não são recomendadas para tartaruga-da-Amazônia nem para outras espécies de répteis, pois houve ampla variação nestas contagens. Os métodos para determinar LT e TT baseados em 2000 eritrócitos nas extensões sanguíneas foram mais aceitáveis porque eles permitem uma diferenciação entre leucócitos e trombócitos, além disso, teve uma variação menor. Os métodos aqui investigados para tartaruga-da-Amazônia, os quais são amplamente usados em outras espécies de répteis, proveram evidências de que o método mais aceitável não é o que usa corantes diluentes e um hemocitômetro

Three Decades of Subterranean Acoustic Communication Studies

The subterranean environment has strongly influenced the evolution of the sensory biology of subterranean rodents. While dark and monotonous tunnels have led to reductions in the visual capabilities of some species, other senses appear to be highly developed in contrast. Among them, the emission of acoustic and seismic signals plays a major role in communication and alertness of subterranean mammals. In this chapter, the ecological and evolutionary conditions that influence the characteristics of vibrational communication in subterranean rodents are reviewed. First, the characteristics of rodents’ burrows and how they dictate the methods used to study subterranean communication are discussed. Second, the properties and roles of vocalizations and seismic signals in subterranean species are examined, including the main hypotheses about the evolution of these signals. Third, what is understood about social and vocal complexity in subterranean rodents is summarized and the similarities and differences in the vocal repertoires of social and solitary groups are analyzed. The chapter ends with a short summary and a consideration of future challenges in the field of subterranean acoustic communication in rodents.Fil: Schleich, Cristian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Francescoli Gilardini, Gabriel Enrique. Universidad de la República; Urugua