|Friday, April 15th|
1:40 PM - 2:00 PM
Via the diet, humans are exposed to a multitude of anthropogenic and natural toxicants that possess immunomodulatory properties. Dendritic cells (DCs) are critical immune cells that bridge the gap between the innate and adaptive branches of the immune system. They constitutively express the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that mediates the toxic effects of many xenobiotics. Therefore, it is important to define the impacts of dietary AhR ligands on DCs to better understand their implications on human health. We hypothesized that dietary AhR ligands, including the environmental contaminant, dioxin and the natural compounds indole-3-carbinol (I3C) and indirubin, will inhibit DC maturation. To test this hypothesis, we utilized bacterial lipopolysaccharide (LPS) to induce maturation of DC2.4 cells (a murine DC cell line) or bone marrow-derived DCs (BMDCs) and evaluated the effects of dioxin, I3C and indirubin on the expression of cell surface biomarkers including CD40, CD80 and CD86 and production of the pro-inflammatory cytokines IL-6 and TNF-?. In both DC2.4 cells and BMDCs all three AhR ligands decreased LPS-induced production of IL-6 and TNF-?. In contrast, differential effects were observed for the three dietary AhR ligands on the LPS-induced expression of cell surface molecules on both DC populations. Interestingly, following qRT-PCR analysis, upregulation of the regulatory genes IDO1, IDO2 and TGF-?3 was detected in LPS-stimulated BMDCs following exposure to dioxin, I3C and indirubin. Collectively, these results indicate that dietary exposure to these AhR ligands can inhibit DC maturation while inducing an immunoregulatory phenotype in these critical white blood cells.
2:00 PM - 2:20 PM
Wildland firefighters (WLFFs) wear fire-resistant uniforms, which differ between fire agencies in layers required. Efficient body-heat dissipation is important for the safety and performance of WLFFs who work arduously in hot environments where hyperthermia leads to exhaustion. PURPOSE: Evaluation of thermoregulatory effects between three WLFF uniforms during work in the heat. METHODS: Nine males (24.6 ±4.1 years, 190.0 ±17.1 cm, 81.0 ±7.9 kg, 11.2 ±3.5 %body fat, 57.4 ±5.4 ml•kg-1•min-1 VO2) completed three separate, three-hour trials of treadmill walking (3 mph, 4% grade) in a heat chamber (37 ± .05°C), with a 10-minute rest period each hour. During each trial, subjects wore different uniforms (Kevlar impregnated Nomex [FSI], Nomex [FSII], and double-layered Nomex [CF]). Variables measured were skin and core temperatures, heart rate, sweat rate, thermal comfort, and rating of perceived exertion. Physiological strain index (PSI), rate of core temperature rise, and body weight changes were calculated. Results were analyzed using a Repeated Measures ANOVA; significance was set at 0.05. RESULTS: No significant differences were found in heart rate, weight change, or skin temperatures. PSI was significantly lower for FSI than CF (p=.038), while FSII trended to be lower (p=.070). Core temperatures were significantly lower during FSI and FSII than CF (p=0.003, p=.044 respectively). CF showed significantly higher rates of core temperature rise (FSI p=0.001, FSII p=0.005). CONCLUSION: Increased uniform layers worn in hot environments result in increased physiological strain. Agencies requiring double layers would benefit from decreasing clothing layers to avoid physiological strain increases and decreases in work performance.
2:20 PM - 2:40 PM
Birds are all around us, yet how much do you know about them? Nature education is lacking in America, and, as a result, our children grow-up with a feeling of disconnected from the world around them. Recent publications, including Richard Louv’s book, Last Child in the Woods, has drawn scientific and public interest to the topic of environmental education. Much of our children’s environmental education is focused worlds away instead of on local issues in their neighborhood. This has driven me to design a curriculum educating elementary school children about birds, something they see everyday. I have worked closely with several elementary school, middle school, and environmental educators to design a nine-week long curriculum focusing or raptors (birds of prey). The material discusses the evolution of birds from reptiles, what makes birds unique, and specific qualities of raptors. However, it also intertwines with everyday subjects such as mathematics, geography, art, writing, and other subjects. Students can follow a raptor that has been tagged with a satellite transmitter as it migrates to South America, all the while studying the culture of the countries the bird passes through. Students can use basic mathematics to calculate how many miles a raptor migrates in one day. They can also observe chick development from a nest camera every morning. The segment ends in a group project researching a specific raptor and writing a non-fiction information pamphlet to share with their classmates. All these activities are designed to promote interactive learning and leave children feeling connected to the world around them.
Joshua F. Goldberg, University of Montana - Missoula
2:40 PM - 3:00 PM
During the fledgling life-stage, young birds have left the nest but still depend on parents, especially for food. Research of the fledgling life-stage has been largely restricted to patterns of survival and dispersal, although, these patterns may interact with parental care and provisioning. I examined parental care behavior, particularly the division of care between parents, during this period by attaching radio transmitters to red-faced warbler (Cardelina rubrifrons) (n = 5) and dark-eyed junco (Junco hyemalis) (n = 10) parents with fledglings. I used radio telemetry to locate parents, noting parent behavior and location with a GPS unit approximately every 2 minutes during 4 to 6 hour focal observations that took place in 1-3 day intervals. I used these data to calculate the distance between fledglings and fledgling mobility. These two species demonstrated different parental care for fledglings. Red-faced warbler parents always split the brood between the male and female, such that both parents did not care for the same fledgling(s), whereas dark-eyed junco parents did not strictly divide their young. These different parental care strategies produced different patterns of fledgling dispersion as offspring aged. Red-faced warbler families tended to diverge with time as parents kept fledglings spatially separated and parent groups drifted apart, whereas dark-eyed junco family groups remained aggregated during the fledgling period with all parents and fledglings staying together in a single area. These differences in parental care behavior may affect the distance traveled by parents to obtain food to provision young. Thus, variation in parental care strategies may affect parental foraging economics, survival, and population dynamics.