To gauge the sensitivity of the female zebra finch song system to estradiol (E2), we used subcutaneous implants to administer various doses of E2 to hatchling female zebra finches. Four different doses of E2 were administered: 50, 15, 5 and 0 μg via subcutaneous silicon "ropes" at hatching, and the brains were examined in adulthood. Further, we examined whether masculinization was all-or-none once a threshold was reached or if the morphology of the song system would show a graded response to the various doses of E2. Finally, we asked if the various dependent measures-volume of song nuclei, neuron size, and neuron number-would show differential sensitivity to E2.Fifteen micrograms was sufficient to masculinize many aspects of the song system and was often as effective as 50 μg, causing a dramatic difference relative to the 0 μg group. Different aspects of the song system seemed differentially sensitive to the effects of E2: volumes of song control nuclei, the size of RA neurons, and the number of HVC neurons were significantly masculinized by 15 μg E2, but the number of RA neurons and HVC and lMAN soma sizes required 50 μg. The results suggest that several developmental processes are influenced by E2, possibly because of multiple sites of action or multiple processes that respond to E2.
For women undergoing first-trimester suction curettage with conscious sedation, there was no clinically meaningful difference in pain relief between paracervical and intracervical lidocaine. Providers should feel confident that both techniques provide equally effective and acceptable analgesia.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.