ABSTRACT
Second-harmonic generation imaging (SHG) captures triple helical collagen molecules near tissue surfaces. Biomedical research routinely utilizes various imaging software packages to quantify SHG signals for collagen content and distribution estimates in modern tissue samples including bone. For the first time using SHG, samples of modern, medieval, and ice age bones were imaged to test the applicability of SHG to ancient bone from a variety of ages, settings, and taxa. Four independent techniques including Raman spectroscopy, FTIR spectroscopy, radiocarbon dating protocols, and mass spectrometry-based protein sequencing, confirm the presence of protein, consistent with the hypothesis that SHG imaging detects ancient bone collagen. These results suggest that future studies have the potential to use SHG imaging to provide new insights into the composition of ancient bone, to characterize ancient bone disorders, to investigate collagen preservation within and between various taxa, and to monitor collagen decay regimes in different depositional environments.
ABSTRACT
Contractile responses of androgen-sensitive smooth muscles such as the vas deferens and seminal vesicles are highly dependent upon the endocrine status of the animal. Although diabetes mellitus produces disturbances in reproductive function, including decreased serum androgen levels, the effects of diabetes on the contractile function of androgen-dependent urogenital smooth muscles have not been conclusively established. The present study compared the effects of streptozotocin-induced diabetes with those of castration on the contractile responses of rat vasa deferentia. Diabetes and castration produced significant decreases in serum testosterone levels, accompanied by significant decreases in vas deferens weights. Contractile responses of vasa deferentia from diabetic rats to carbachol, ATP, and phenylephrine were significantly increased, and responses to nerve stimulation were decreased. Similar results were obtained with vasa deferentia from castrated rats. Castration produced significant increases in contractile responses of vasa deferentia to carbachol and phenylephrine and decreased responses to nerve stimulation. The data suggest that both castration and diabetes produce a denervation-like supersensitivity which is specific for receptor-mediated processes.
