Metaphyseal chondroblastoma in a pediatric patient.

Chondroblastoma is a rare, benign neoplasm usually located in the epiphyses and apophyses of the long bones in the immature skeleton. Radiologically, these tumors have a classic appearance of a lytic lesion with chondroid matrix surrounded by a thin sclerotic rim. Here, we describe the case of a 5-year-old male who presented with a chondroblastoma unusually located exclusively in the metaphyseal region, which led to an elusive diagnosis. The presence of tumors outlying the traditional location or epidemiological spectrum, along with the potential for histopathological misdiagnosis, can pose a diagnostic and therapeutic challenge for the treating team.

Do marmosets care to share? Oxytocin treatment reduces prosocial behavior toward strangers.

Cooperatively-breeding and socially-monogamous primates, like marmosets and humans, exhibit high levels of social tolerance and prosociality toward others. Oxytocin (OXT) generally facilitates prosocial behavior, but there is growing recognition that OXT modulation of prosocial behavior is shaped by the context of social interactions and by other motivational states such as arousal or anxiety. To determine whether prosociality varies based on social context, we evaluated whether marmoset donors (Callithrix penicillata) preferentially rewarded pairmates versus opposite-sex strangers in a prosocial food-sharing task. To examine potential links among OXT, stress systems, and prosociality, we evaluated whether pretrial cortisol levels in marmosets altered the impact of OXT on prosocial responses. Marmosets exhibited spontaneous prosociality toward others, but they did so preferentially toward strangers compared to their pairmates. When donor marmosets were treated with marmoset-specific Pro(8)-OXT, they exhibited reduced prosociality toward strangers compared to marmosets treated with saline or consensus-mammalian Leu(8)-OXT. When pretrial cortisol levels were lower, marmosets exhibited higher prosociality toward strangers. These findings demonstrate that while marmosets show spontaneous prosocial responses toward others, they do so preferentially toward opposite-sex strangers. Cooperative breeding may be associated with the expression of prosociality, but the existence of a pair-bond between marmoset partners appears to be neither necessary nor sufficient for the expression of spontaneous prosocial responses. Furthermore, high prosociality toward strangers is significantly reduced in marmosets treated with Pro(8)-OXT, suggesting that OXT does not universally enhance prosociality, but, rather OXT modulation of prosocial behavior varies depending on social context.

Evidence for a synchronization of hormonal states between humans and dogs during competition.

Social interactions with humans have been shown to influence hormonal processes in dogs, but it is unclear how the hormonal states of humans factor into this relationship. In this study, we explored the associations between changes in the cortisol levels of dogs with humans' hormonal changes, behavior, and perceptions of their performance at an agility competition. A total of 58 dogs and their handlers (44 women, 14 men) provided saliva samples before and after competing. Dogs' saliva samples were later assayed for cortisol and humans' samples for cortisol and testosterone. Following the competition, handler-dog interactions were observed for affiliative and punitive behavior towards their dogs, and handlers completed questionnaires that included personal ratings of their performance. Structural equation modeling revealed that elevations in handlers' cortisol levels were associated with increases in their dogs' cortisol levels. Handlers' affiliative and punitive behaviors towards their dogs following competition were associated with their ratings of their performance, but these variables were unrelated to changes in their own cortisol levels and their dogs', implying their behavior did not mediate the relationship. These findings suggest that changes in the hormonal states were reflected between humans and their dogs, and this relationship was not due to handlers' perceptions of their performance or the behaviors we observed during post-competition social interactions. This study is one of the first to provide evidence for a synchronization of hormonal changes between species.