RESUMO
The widely used herbicide atrazine (ATR) may have endocrine-associated adverse effects, including on behavior. In this study, 120 adult freshwater mussels, Elliptio complanata, were exposed to ATR at the environmentally relevant concentrations of 1.5, 15, or 150 µg/L. Burrowing depth was evaluated hourly for 6 h and at sacrifice animals were sexed by gonad smear. Female controls burrowed overall approximately 30% less than males, the first report of sexual dimorphism in this behavior. Atrazine at 15 µg/L feminized burrowing in both sexes, in that exposed animals burrowed 20% less than their same-sex controls. Males treated with 1.5 µg /L ATR displayed approximately 20-fold higher vitellogenin (VTG) levels than same-sex controls. Higher concentrations of ATR were not associated with increasing effects. A scatterplot showed a weak binomial curve associating low burrowing with high VTG levels. Taken together, these data suggest a nonlinear dose response in behavioral and physiological feminization produced by ATR and support the need to reconsider the widespread use of this compound.
Assuntos
Atrazina/toxicidade , Comportamento Animal/efeitos dos fármacos , Bivalves/efeitos dos fármacos , Feminização/induzido quimicamente , Gônadas/efeitos dos fármacos , Herbicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Bivalves/fisiologia , Relação Dose-Resposta a Droga , Feminino , Água Doce , Masculino , Caracteres Sexuais , Fatores Sexuais , Vitelogeninas/metabolismoRESUMO
Sedation is used almost universally in the care of critically ill patients, especially in those who require mechanical ventilatory support or other life-saving invasive procedures. This review will focus on the sedation strategies for critically ill patients and the pharmacology of commonly used sedative agents. The role of neuromuscular blocking agents in the ICU will be examined and the pharmacology of commonly used agents is reviewed. Finally a strategy for rational use of these sedative and neuromuscular blocking agents in critically ill patients will be proposed.
Assuntos
Sedação Profunda , Hipnóticos e Sedativos/administração & dosagem , Bloqueadores Neuromusculares/administração & dosagem , Respiração Artificial/métodos , Algoritmos , Cuidados Críticos , Estado Terminal/terapia , Sedação Profunda/efeitos adversos , Monitoramento de Medicamentos , Humanos , Hipnóticos e Sedativos/efeitos adversos , Bloqueadores Neuromusculares/efeitos adversos , Paralisia/induzido quimicamente , Desmame do RespiradorRESUMO
Multiple mating by females characterizes most insect species, but is relatively uncommon in social insects. Females may mate with multiple mates because they experience the direct benefits of increased survival or fecundity, to acquire high quality mates, or to lower the risk of reduced fecundity by mating with incompatible males. We used the extensive natural variation in mating frequency in the western harvester ant, Pogonomyrmex occidentalis, to test the hypothesis that increased mating by the queen leads to an increase in colony performance. Colonies with greater genetic diversity began to forage earlier in the day and foraged for longer time periods. The workers which initiated foraging were a nonrandom subset of the genotypes present in the colony. We used a statistical approach to correctly predict the direction and magnitude of the correlation between genetic diversity and colony foraging activity.