Endogenous oxytocin, cortisol, and testosterone in response to group singing.

Humans have sung together for thousands of years. Today, regular participation in group singing is associated with benefits across psychological and biological dimensions of human health. Here we examine the hypothesis that a portion of these benefits stem from changes in endocrine activity associated with affiliation and social bonding. Working with a young adult choir (n = 71), we measured changes salivary concentrations of oxytocin, cortisol, and testosterone from before and after four experimental conditions crossing two factors: vocal production mode (singing vs. speaking) and social context (together vs. alone). Salivary oxytocin and cortisol decreased from before to after the experimental manipulations. For oxytocin the magnitude of this decrease was significantly smaller after singing compared to speaking, resulting in concentrations that were significantly elevated after singing together compared to speaking together, after controlling for baseline differences. In contrast, the magnitude of the salivary cortisol decreases was the same across experimental manipulations, and although large, could not be separated from diurnal cycling. No significant effects were found in a low-powered exploratory evaluation of testosterone (tested only in males). At a psychological level, we found that singing stimulates greater positive shifts in self-perceived affect compared to speaking-particularly when performed together-and that singing together enhances feelings of social connection more than speaking together. Finally, measurements of heart rate made for a subset of participants provide preliminary evidence regarding physical exertion levels across conditions. These results are discussed in the context of a growing multidisciplinary literature on the endocrinological correlates of musical behavior. We conclude that singing together can have biological and psychological effects associated with affiliation and social bonding, and that these effects extend beyond comparable but non-musical group activities. However, we also note that these effects appear heavily influenced by broader contextual factors that shape social dynamics, such as stress levels, the intimacy of interactions, and the status of existing relationships.

Cathepsin D targeted by acid sphingomyelinase-derived ceramide.

Ceramide has been recognized as a common intracellular second messenger for various cytokines, growth factors and other stimuli, such as CD95, chemotherapeutic drugs and stress factors. To understand the role of ceramide during apoptosis and other cellular responses, it is critically important to characterize direct targets of ceramide action. In this paper, we show that ceramide specifically binds to and activates the endosomal acidic aspartate protease cathepsin D. Direct interaction of ceramide with cathepsin D results in autocatalytic proteolysis of the 52 kDa pre-pro cathepsin D to form the enzymatically active 48/32 kDa isoforms of cathepsin D. Acid sphingomyelinase (A-SMase)-deficient cells show decreased cathepsin D activity, which could be reconstituted by transfection with A-SMase cDNA. The results of our study identify cathepsin D as the first endosomal ceramide target that colocalizes with and may mediate downstream signaling effects of A-SMase.

Surgical treatment of hyperthyroidism in children.

During the past ten years, subtotal thyroidectomy for hyperthyroidism was performed upon 43 children at Childrens Hospital of Los Angeles. There were no deaths, no recurrent laryngeal nerve injuries and no permanent hypoparathyroidism. During the one to ten year follow-up period, one patient had recurrent hyperthyroidism develop and was treated with 131I. Twenty-five patients are hypothyroid and require thyroid supplement; 14 are euthyroid and receiv no medication. Postoperative thyroid function did not correlate well with gland remnant size, degree of fibrosis or the extent of lymphoid follicle formation. Lymphocytic infiltration was more severe in patients who had hypothyroidism develop postoperatively. Transient hypocalcemia developed in 22 patients. The effectiveness and safety of the surgical treatment for hyperthyroidism in children is reaffirmed, and it is advocated for consideration over 131I or prolonged medical therapy.