Sex-Specific Differences in Oxytocin Receptor Expression and Function for Parental Behavior

Parental care is among the most profound behavior expressed by humans and other animals. Despite intense interest in understanding the biological basis of parental behaviors, it remains unknown how much of parenting is encoded by the genome and which abilities instead are learned or can be refined by experience. One critical factor at the intersection between innate behaviors and experience-dependent learning is oxytocin, a neurohormone important for maternal physiology and neuroplasticity. Oxytocin acts throughout the body and brain to promote prosocial and maternal behaviors and modulates synaptic transmission to affect neural circuit dynamics. Recently we developed specific antibodies to mouse oxytocin receptors, found that oxytocin receptors are left lateralized in female auditory cortex, and examined how oxytocin enables maternal behavior by sensitizing the cortex to infant distress sounds. In this study we compare oxytocin receptor expression and function in male and female mice. Receptor expression is higher in adult female left auditory cortex than in right auditory cortex or males. Developmental profiles and mRNA expression were comparable between males and females. Behaviorally, male and female mice began expressing parental behavior similarly after cohousing with experienced females; however, oxytocin enhanced parental behavior onset in females but not males. This suggests that left lateralization of oxytocin receptor expression in females provides a mechanism for accelerating maternal behavior onset, although male mice can also effectively co-parent after experience with infants. The sex-specific pattern of oxytocin receptor expression might genetically predispose female cortex to respond to infant cues, which both males and females can also rapidly learn.

[Perioperative antibiotic prophylaxis at the Clinic of Reconstructive Surgery of the Zurich University Hospital]

With the goal of ensuring maximal safety, surgeons tend to apply antibiotic prophylaxis generously to patients undergoing selective operative procedures. However, the indiscriminate or inappropriate use of prophylactic antibiotics i) leads to the selection of resistant microbial organisms and ii) results in an increase in general medical treatment costs. Given this controversy, the clinic of reconstructive surgery implemented in 1999 a set of guidelines for the proper use of antibiotics. Antibiotic prophylaxis was defined as a pre- or perioperative application of antibiotics as a single to maximum triple-shot dose. It was recommended only for operations involving special risk factors or the implantation of alloplastic material. The recommended medication of choice was the widely-accepted standard first-generation cephalosporin product Cefazolin. We have carried out a quality control trial to analyse prospectively our own experience with the implementation of these guidelines and to compare results with a retrospective group of patients. A total of 792 patients (441 in the retrospective group, 351 in the prospective group) were enrolled in the study. About one third of all patients received an antibiotic prophylaxis. Of these, about 3/4 received the antibiotic prophylaxis without having one of the above-mentioned indications. We observed that 35% of all prophylaxis were given for breast surgery, followed by surgery for scar revisions and lipodystrophy. The most commonly used antibiotic was Cefuroxim rather than Cefazolin. There was no significant reduction in the general application of antibiotic prophylaxis yet apparent in the prospective group. However, there was a clear increase in the use of Cefazolin from 0.2% to 13.2%. We conclude that guidelines can be created to reduce the incidence of uninformed and inappropriate decisions, but their implementation requires time, motivation, and thorough and repeated information campaigns.