Historical Environment Is Reflected in Modern Population Genetics and Biogeography of an Island Endemic Lizard (Xantusia riversiana reticulata).

The restricted distribution and isolation of island endemics often produces unique genetic and phenotypic diversity of conservation interest to management agencies. However, these isolated species, especially those with sensitive life history traits, are at high risk for the adverse effects of genetic drift and habitat degradation by non-native wildlife. Here, we study the population genetic diversity, structure, and stability of a classic "island giant" (Xantusia riversiana, the Island Night Lizard) on San Clemente Island, California following the removal of feral goats. Using DNA microsatellites, we found that this population is reasonably genetically robust despite historical grazing, with similar effective population sizes and genetic diversity metrics across all sampling locations irrespective of habitat type and degree of degradation. However, we also found strong site-specific patterns of genetic variation and low genetic diversity compared to mainland congeners, warranting continued special management as an island endemic. We identify both high and low elevation areas that remain valuable repositories of genetic diversity and provide a case study for other low-dispersal coastal organisms in the face of future climate change.

Relation between C-reactive protein levels and body composition in a multiethnic sample of school children in Hawaii.

OBJECTIVES: Adipose cells secrete proinflammatory cytokines that stimulate hepatic production of C-reactive protein (CRP). CRP levels are associated with adiposity levels in adults, adolescents, and older children but not in young children (age 2-3). This study examined the relation between CRP, adiposity, and cardiovascular and metabolic variables including blood pressure, glucose, and blood lipids in two young cohorts of children, averaging approximately 5.5 and 8.5 years, respectively. METHODS: Children (N = 125) from eight elementary schools in the multiethnic community of Hilo Hawaii were recruited to fill out questionnaires, undergo anthropometrics and air displacement plethysmography, have resting blood pressure measured, and provide a finger stick blood sample for analysis of CRP, glucose, and blood lipids. RESULTS: There were no significant differences between the cohorts in ethnic make up, household income, or parents' educational attainment. No significant relation was found between CRP and either adiposity or cardiovascular/metabolic variables in the younger cohort. However, significant correlations were found between CRP and adiposity measures and blood pressure in the older cohort. There was no marked difference in association of CRP with BMI versus waist circumference or waist-to-hip ratio. In neither cohort was CRP significantly related to glucose or blood lipids. CONCLUSIONS: Both amount of fat mass and time duration for possessing the adipose tissue may be important factors in determining the relation between CRP and both adiposity and blood pressure.

Ozone exposure affects feeding and locomotor behavior of adult Bufo marinus.

Ozone (O3), a reactive component of air pollution, depresses feeding and voluntary locomotor behavior in laboratory rodents, but the effects of O3 on amphibian behavior are not known. We evaluated the effects of 4 h of exposure to air or ozone (0.6 microl/L), on two ecologically relevant behaviors of the toad Bufo marinus. Toads were offered five mealworms at 1, 24, and 48 h after exposure. One hour after exposure, O3-exposed toads ate fewer mealworms than did air-exposed toads (Fisher exact test, p=0.005). Within 24 h after exposure, all toads ate four or five mealworms. Because movement is a key component of toad feeding behavior, we tested additional toads (n=25) for voluntary locomotor behavior during three 1-h trials in a 2.9-m2 open-field arena. Mean (+/-standard deviation) total distance moved was: pre-exposure, 29+/-19.5 m; 1-h postexposure, 13+/-15.6 m; and 24-h postexposure, 17+/-17.4 m. The means were not statistically different by repeated measures analysis of covariance. Therefore, our results suggest that a single 4-h exposure to O3 depresses toad feeding behavior after exposure but had little effect on voluntary locomotor behavior.

Effects of ozone exposure on nonspecific phagocytic capacity of pulmonary macrophages from an amphibian, Bufo marinus.

Pulmonary macrophages are an important component of immune defense against inhaled foreign particles and microorganisms. In humans and other mammals, exposure to moderate amounts of ozone (O3) can inhibit functional capacities of alveolar macrophages. In many wilderness areas downwind of urban centers, ozone levels frequently exceed national standards. We report results of 4-h inhalation exposures to 0.8 parts per million O3 on pulmonary macrophage viability and phagocytosis capacity in marine toads, Bufo marinus. At 1 and 24 h after ozone exposure, macrophages had reduced in vitro capacity to phagocytize fluorescent polystyrene microspheres. By 48 h postexposure, there were no differences in these macrophage functions between ozone- and air-exposed toads. Macrophage yield did not differ among exposure groups nor did exposure to elevated temperatures (30 degrees C) for up to 48 h affect recovery of macrophages. However, compared with the millions of macrophages per milliliter recovered in mammals by similar procedures, pulmonary macrophage yield was typically in the range of 50 to 200 x 10(3) per milliliter extracted fluid. These results are the first to report effects of an air pollutant on amphibian immune system function and suggest a possible role of oxidant air pollutants in regional declines of amphibian populations.

Respiratory and behavioral effects of ozone on a lizard and a frog.

Ozone at concentrations found in urban air pollution is known to have significant physiological effects on humans and other mammals. Exposure of the lizard, Sceloporus occidentalis, to 0.6 ppm ozone for 4 h at 25 degrees C induced 1.6 degrees C of behavioral hypothermia immediately following exposure, but selected body temperature recovered to control 35.3 degrees C the next day. Lizards exposed at 35 degrees C to 0.6 ppm ozone for 4 h selected body temperatures 1.9 degrees C below controls after exposure, and the behavioral hypothermic response persisted and increased to 3.3 degrees C the following day. Four-hour exposures of the frog, Pseudacris cadaverina, to 0.2 to 0.8 ppm ozone resulted in concentration-dependent alterations of respiration including depression of lung ventilation and oxygen consumption and the adoption of a low profile posture that reduced the exposed body surface. Ozone levels in wilderness habitats downwind of urban sources can potentially have stressful physiological effects on wildlife. Defensive physiological and behavioral reactions to ozone exposure may interfere with routine activities, and oxidant air pollution may be in part responsible for observed wildlife population declines.

Outcomes of a randomized trial of hyperfractionated cranial radiation therapy for treatment of high-risk acute lymphoblastic leukemia: therapeutic efficacy and neurotoxicity.

PURPOSE: We evaluated 8-year survival and late neuropsychologic toxicity in children with acute lymphoblastic leukemia treated in a randomized clinical trial to test whether hyperfractionated (twice daily) cranial radiation therapy (CRT) can reduce incidence and severity of late toxicities associated with 18 Gy of CRT. PATIENTS AND METHODS: Between 1987 and 1995, 369 children treated on two consecutive Dana-Farber Cancer Institute Consortium protocols for high-risk acute lymphoblastic leukemia were randomly assigned to conventionally fractionated CRT (CFX) or hyperfractionated CRT (HFX) to a total dose of 18 Gy. Neuropsychologic testing was completed for 125 of 287 children in continuous complete remission. Event-free and overall survival, as well as neuropsychologic function, were compared for the two arms of the protocol. RESULTS: Eight-year event-free survival (+/- SE) was 80% +/- 3% for children randomly assigned to CFX and 72% +/- 3% for HFX (P =.06). Overall survival was 85% +/- 3% for CFX and 78% +/- 3% for HFX (P =.06). CNS relapses occurred in 2.8% of patients receiving CFX and 2.7% receiving HFX (P =.99). Cognitive function for both groups was solidly in the average range, with no group differences in intelligence, academic achievement, visuospatial reasoning, or verbal learning. Children on the HFX arm exhibited a modest advantage for visual memory (P <.05). CONCLUSION: HFX provides no benefit in terms of cognitive late effects and may compromise antileukemic efficacy. HFX should not be substituted for conventionally dosed CRT in children who require radiation therapy for treatment of acute lymphoblastic leukemia.

Toxicity of chemical components of fine particles inhaled by aged rats: effects of concentration.

This study tested the hypothesis that exposure to mixtures containing fine particles and ozone (O3) would cause pulmonary injury and decrements in functions of immunological cells in exposed rats (22-24 months old) in a dose-dependent manner. Rats were exposed to high and low concentrations of ammonium bisulfate and elemental carbon and to 0.2 ppm O3. Control groups were exposed to purified air or O3 alone. The biological end points measured included histopathological markers of lung injury, bronchoalveolar lung fluid proteins, and measures of the function of the lung's innate immunological defenses (macrophage antigen-directed phagocytosis and respiratory burst activity). Exposure to O3 alone at 0.2 ppm did not result in significant changes in any of the measured end points. Exposures to the particle mixtures plus O3 produced statistically significant changes consistent with adverse effects. The low-concentration mixture produced effects that were statistically significant compared to purified air but, with the exception of macrophage Fc receptor binding, exposure to the high-concentration mixture did not. The effects of the low- and high-concentration mixtures were not significantly different. The study supports previous work that indicated that particle + O3 mixtures were more toxic than O3 alone.

Exercising animal models in inhalation toxicology: interactions with ozone and formaldehyde.

Exercise during exposure to inhaled toxicants increases inhaled dose rate and alters dose distribution within the respiratory tract, and exercise has long been recognized as a critical exposure variable. While modern inhalation exposure studies with human subjects routinely use an exercise protocol, most investigations with animal models are performed with resting subjects. Animal inhalation exposures under exercising conditions frequently induce respiratory toxic effects well beyond that expected from the simple increase in ventilation dose rate. Different classes of irritants can induce different reflex breathing patterns, and small mammals have different capacities for hypothermic or hyperthermic responses to rest or exercise exposure. Respiratory tract injury and breathing pattern responses of rats to upper and lower airway irritants ozone and formaldehyde were measured under conditions of rest and exercise to illustrate the complexities of comparison to human exposures. In addition to the exercise effects on dose and dose distribution and the possibility of hypo- or hyperthermic responses, exercise enhancement of inhalation injury may also be related to a combination of toxicant-induced disruption of the pulmonary epithelial permeability barrier and exercise-induced pulmonary capillary stress failure.