Testosterone-cortisol dissociation in children exposed to prenatal maternal stress, and relationship with aggression: Project Ice Storm.

Prenatal maternal stress (PNMS) has been associated with postnatal behavioral alterations that may be partly explained by interactions between the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes. Yet it remains unclear whether PNMS leads to enduring HPA-HPG alterations in the offspring, and whether HPA-HPG interactions can impact behavior during development, in particular levels of aggression in childhood. Here we investigated the relationship between a marker for HPG axis function (baseline testosterone) and a marker for HPA axis response (cortisol area under the curve) in 11½-year-olds whose mothers were exposed to the 1998 Quebec ice storm during pregnancy (n = 59 children; 31 boys, 28 girls). We examined (a) whether the degree of objective or subjective PNMS regulates the testosterone-cortisol relationship at age 11½, and (b) whether this testosterone-cortisol relationship is associated with differences in aggressive behavior. We found that, at lower levels of subjective PNMS, baseline testosterone and cortisol reactivity were positively correlated; in contrast, there was no relationship between these hormones at higher levels of subjective PNMS. Cortisol response moderated the relationship between testosterone and aggression. These results support the notion PNMS may explain variance in fetal HPA-HPG interactions, and that these interactions may be associated with aggressive behavior in late childhood.

Efficacy of the LouseBuster, a new medical device for treating head lice (Anoplura:Pediculidae).

Human head lice (Pediculus humanus capitis De Geer) occur worldwide and infest millions of children and adults every year. Head lice infestations, which are known as pediculosis capitis, are psychologically stressful, physically irritating, and are one of the leading causes of K-6 school absence. The prevalence of head lice in many countries is increasing rapidly because of resistance to chemicals used in many head lice treatments. We tested the efficacy of an alternative method for controlling head lice, the LouseBuster, a custom-built medical device designed to kill head lice and their eggs using controlled, heated air. A total of 56 infested subjects was treated with the LouseBuster, and the efficacy of the treatment was evaluated by comparing the viability of lice and eggs on randomly assigned pre- and posttreatment sides of each subject's scalp. We evaluate treatment efficacy in the hands of novice versus experienced operators. We also evaluate treatment efficacy on different hair types and at different ambient humidities. Overall mortality of lice and eggs was 94.8% after treatment by experienced operators. Novice operators also achieved good results after a short training session; their results did not differ significantly from those of experienced operators. No adverse events were associated with the LouseBuster treatment. The LouseBuster is efficacious for killing head lice and their eggs. The use of heated air is appealing because it is a fast, safe, nonchemical treatment. Head lice are also unlikely to evolve resistance to desiccation, which is the apparent mode of action.

Conditioned partner preference in female rats for strain of male.

Female rats show conditioned place preference following paced copulation, and we have recently demonstrated that pairing almond odor with paced copulation induces a conditioned partner preference for almond-scented males. The present study examined whether cues of two different strains of male (albino and pigmented) induce a conditioned partner preference for the strain of male associated with paced copulation. Ovariectomized, hormone-primed Wistar (W) or Long-Evans (LE) female rats received 10 conditioning trials at 4-day intervals. In the Wistar-pacing group females copulated with W males in a chamber bisected by a 4-hole partition that only the female could pass through. Four days later, they copulated with LE males without the partition. The Long-Evans-pacing group received the opposite association. In the final preference test all females chose freely between two males tethered in opposite corners of an open field, one W and one LE. Regardless the strain of male, females displayed more solicitations toward the pacing-related male, and most of the females received their first ejaculation from that male. The preference was facilitated if the pacing-related male was of the same strain as the female. These results suggest that female rats have an unconditioned preference for males of the same strain, but this preference can be switched towards males of a different strain if that male is associated with the sexual reward induced by paced copulation.