Differential effects of ethanol on behavior and GABAA receptor expression in adult zebrafish (Danio rerio) with alternative stress coping styles.

Variation in stress responses between individuals are linked to factors ranging from stress coping styles to sensitivity of neurotransmitter systems. Many anxiolytic compounds (e.g. ethanol) can increase stressor engagement through modulation of neurotransmitter systems and are used to investigate stress response mechanisms. There are two alternative suites of correlated behavioral and physiological responses to stressors (stress coping styles) that differ in exploration tendencies: proactive and reactive stress coping styles. By chronically treating individuals differing in stress coping style with ethanol, a GABA-acting drug, we assessed the role of the GABAergic system on the behavioral stress response. Specifically, we investigated resulting changes in stress-related behavior (i.e. exploratory behavior) and whole-brain GABAA receptor subunits (gabra1, gabra2, gabrd, & gabrg2) in response to a novelty stressor. We found that ethanol-treated proactive individuals showed lower stress-related behaviors than their reactive counterparts. Proactive individuals showed significantly higher expression of gabra1, gabra2, and gabrg2 compared to reactive individuals and ethanol treatment resulted in upregulation of gabra1 and gabrg2 in both stress coping styles. These results suggest that impacts of ethanol on stress-related behaviors vary by stress coping style and that expression of select GABAA receptor subunits may be one of the underlying mechanisms.

Repeatability and reliability of exploratory behavior in proactive and reactive zebrafish, Danio rerio.

Behavioral responses to novel situations often vary and can belong to a suite of correlated behaviors. Characteristic behaviors of different personality types (e.g. stress coping styles) are generally consistent across contexts and time. Here, we compare the repeatability and reliability of exploratory behaviors between zebrafish strains selectively bred to display contrasting behavioral responses to stressors that represent the proactive-reactive axis. Specifically, we measure exploratory behavior of individual fish in an open field test over five weeks. We quantified the stationary time, average swimming speed and time spent by a fish in the center area. We found a number of strain differences for each behavioral measure. Stationary time was the most repeatable and reliable measure for assessing proactive-reactive behavioral differences. Reactive zebrafish generally showed the highest reliability and repeatability of exploratory behavior compared to proactive zebrafish and a separate wild caught strain. Given the increased interest in the evolutionary consequences and proximate mechanisms of consistent individual differences, it will be important to continue to investigate how different selective pressures may influence expression of stress coping styles and their effects on the consistency of an animal's behavior.

Characterizing nanoscale scanning probes using electron microscopy: A novel fixture and a practical guide.

The nanoscale geometry of probe tips used for atomic force microscopy (AFM) measurements determines the lateral resolution, contributes to the strength of the tip-surface interaction, and can be a significant source of uncertainty in the quantitative analysis of results. While inverse imaging of the probe tip has been used successfully to determine probe tip geometry, direct observation of the tip profile using electron microscopy (EM) confers several advantages: it provides direct (rather than indirect) imaging, requires fewer algorithmic parameters, and does not require bringing the tip into contact with a sample. In the past, EM-based observation of the probe tip has been achieved using ad hoc mounting methods that are constrained by low throughput, the risk of contamination, and repeatability issues. We report on a probe fixture designed for use in a commercial transmission electron microscope that enables repeatable mounting of multiple AFM probes as well as a reference grid for beam alignment. This communication describes the design, fabrication, and advantages of this probe fixture, including full technical drawings for machining. Further, best practices are discussed for repeatable, non-destructive probe imaging. Finally, examples of the fixture's use are described, including characterization of common commercial AFM probes in their out-of-the-box condition.

Newborn falls in-hospital: time to address the issue.

Newborn falls in-hospital are considered rare and mostly accidental. Few studies are available explaining such accidents. The number of cases may be under reported by parents because of the inevitable sense of guilt they experience. Although deaths have been rarely reported, such accidents may be associated with serious outcomes. An urgent assessment by both the midwifery and paediatric teams should be undertaken following the reporting of such accidents. This paper explains what is meant by newborn falls, presents some relevant literature and uses a case study involving a newborn in hospital to form the basis of a discussion. Importantly it is felt that there is a need to raise awareness of the potential of these accidents amongst health professionals. We hope this paper goes some way towards highlighting some key issues and, moreover, increases awareness of newborn falls in hospital.

Potential complications of neonatal cephalhaematoma in the community: when to refer to the paediatric team?

Neonatal cephalhaematoma is commonly seen after a minor birth trauma, e.g. from vacuum-assisted deliveries. It is usually considered benign and resolves spontaneously without any treatment. Considerable parental anxiety may be associated with this condition and thus primary health care professionals play a significant role in providing reassurance to the new parents. Complications, although rare, are known to occur and can be potentially serious. A degree of uncertainty is often seen among primary health care professionals about whether to refer such cases to hospital. Recognition of the complications by primary health care professionals and early involvement of the paediatric services are essential to prevent serious complications such as meningitis and osteomyelitis. A case of bilateral cephalhaematoma is presented which was suspected to be infected and needed in-patient hospital care. The potential complications of a cephalhaematoma are discussed and guidelines provided for expediting early and appropriate referral of complicated cases to the paediatric services.