Detection of human papillomavirus DNA in biopsy-proven cervical squamous intraepithelial lesions in pregnant women.

This study analyzed cervical squamous intraepithelial lesions (SILs) in pregnant women for human papillomavirus (HPV) using in situ hybridization analysis. HPV DNA was detected in 77% (23/30) of low-grade SILs as compared to 89% of such lesions in nonpregnant women. The detection rate in high-grade SILs was 41% (9/22) compared to 70% in nonpregnant women. Analysis by the polymerase chain reaction showed that the detection rates were similar (96-100%) for low- and high-grade lesions in pregnant and nonpregnant women, which demonstrates that in situ negative tissues indeed contained HPV DNA. Low-grade SILs contained a heterogeneous group of at least 14 different HPV types, whereas most high-grade SILs contained HPV 16. We concluded that cervical SILs in pregnant women are invariably associated with HPV. Further study is needed to determine which of several possible variables, such as the age of the lesion and the viral copy number, may explain the apparent decreased detection rate of HPV by in situ hybridization in SILs during pregnancy.

Postpartum aggression and plasma prolactin levels in mice exposed to lead.

Young-adult, female Binghamton Heterogeneous Stock (HET) mice either were exposed to lead via drinking water from birth, or not. Eight days after giving birth to their first litter of pups (at about 70-75 days of age), postpartum aggression tests were conducted. Unfamiliar Het male intruders were introduced to the primiparous dams' nesting cages, and dyadic behavioral interactions were observed for 10 min. We also obtained plasma prolactin levels of these females, or others who had similar histories, but were not tested for maternal aggression. Behaviorally, the intensity of fighting was greater in lead-exposed pairs than in water-control pairs that fought. However, the percentage of pairs displaying aggressive behavior and average latency to initial contact were similar, regardless of dietary history. Plasma prolactin levels implied that lead exposure alone decreased circulating prolactin in primiparous Het dams eight days postpartum, but confrontation with a male intruder also was sufficient to reduce prolactin levels in water-control dams. It would be reasonable to assume that such changes in prolactin are dopaminergically mediated. The data suggest that lead ingestion may, in a species and strain specific manner, modify: 1) neurotransmitter and hormonal systems and 2) social behavior. The major effect of "subclinical" lead toxicity may be to change the limits of an organism's ability to cope with its environment.

Lead, age and aggression in male mice.

The impact of eleven weeks of ingestion of a 0.5% lead acetate solution on agonistic behavior of male Binghamton Heterogeneous stock mice (either 120 or 660 days of age) was examined. Similar aged mice were paired for aggression testing. Not surprisingly, younger mice, regardless of fluid history fought more vigorously than older mice. However, when mice of similar fluid history were paired together, lead ingestion decreased the latency to fight only in older mice. Regardless of their prior fighting history, when lead treated mice fought similar aged controls, the lead exposed mice in younger pairs were typically subordinate; but in older pairs, lead exposed mice were dominant. These results, coupled with extant literature concerning age-related changes in endocrine function, pituitary-adrenal activity, and lead-induced changes in hippocampal function suggest that future work directed at mechanism(s) underlying lead-induced alterations in agonistic behavior should consider life span changes in biobehavioral profiles.

Lead exposure and agonistic behavior of adult mice of two ages.

Adult male Heterogeneous stock (HET) mice were exposed to a 0.5% lead acetate solution when they were either 65 or 330 days of age. Fifteen weeks later they were paired with same age (young or old) water control HET mice and tested for aggression. All pairs of younger mice fought and six out of eleven pairs of older mice exhibited agonistic behavior. Although not all pairs of mice which fought achieved dominance, when dominant/subordinate relationships were established, the younger adults exposed to lead typically were subordinate. In contrast, older adults exposed to lead were always dominant. Differences in agonistic behavior patterns also were noted, with younger adults displaying more frequent and longer bouts of fighting than the older mice.

Influence of environmental rearing history and postsurgical environmental change on the septal rage syndrome in mice.

Reactivity to handling was examined in Binghamton Heterogeneous (HET) mice given septal lesions or control surgery following 5 weeks of postweaning rearing in enriched or restricted environments. Three housing conditions were employed: continuous enrichment, continuous restriction (both pre- and postsurgically), and a group switched from environmental enrichment to restriction 24 hours after surgery. The restricted mice were more reactive to handling than the enriched mice presurgically (60 days old), and interactions of housing conditions and surgery were found over the seven day postsurgical handling and testing period. The restricted mice given septal lesions greatly increased in reactivity postsurgically, while the intact controls declined in reactivity over the postsurgical week. The enriched septals were only moderately increased over the low presurgical reactivity baseline, and were much less reactive than the restricted septals. Perhaps the most remarkable finding was the dramatic and immediate increase in reactivity in the septals switched from enrichment to restriction, while intact controls showed no effect of the switch. These results emphasize the importance of experience in determining the effects of septal damage, and may be useful in examining other correlates of septal rage.