Predicting spatial patterns of eagle migration using a mesoscale atmospheric model: a case study associated with a mountain-ridge wind development

High resolution numerical atmospheric modeling around a mountain ridge in Northeastern British Columbia (BC), Canada was performed in order to examine the influence of meteorology and topography on Golden Eagle migration pathways at the meso-scale (tens of km). During three eagle fall migration periods (2007-2009), local meteorological conditions on the day of peak bird counts were modeled using the Regional Atmospheric Modeling System (RAMS) mesoscale model. Hourly local surface wind speed, wind direction, temperature, pressure and relative humidity were also monitored during these migration periods. Eagle migration flight paths were observed from the ground and converted to three-dimensional tracks using ArcGIS. The observed eagle migration flight paths were compared with the modeled vertical velocity wind fields. Flight tracks across the study area were also simulated using the modeled vertical velocity field in a migration model based on a fluid-flow analogy. It was found that both the large-scale weather conditions and the horizontal wind fields across the study area were broadly similar on each of the modeled migration days. Nonetheless, the location and density of flight tracks across the domain varied between days, with the 2007 event producing more tracks to the southwest of the observation location than the other 2 days. The modeled wind fields suggest that it is not possible for the eagles to traverse the study area without leaving updraft regions, but birds do converge on the locations of updrafts as they move through the area. Statistical associations between observed eagles positions and the vertical velocity field suggest that to the northwest (and to a lesser extent the southwest) of the main study ridge (Johnson col), eagles can always find updrafts but that they must pass through downdraft regions in the NE and SE as they make their way across the study area. Finally, the simulated flight tracks based on the fluid-flow model and the vertical velocity fields are in general agreement with the observed flight track patterns. Our results suggest that use of high resolution meteorological fields to locate the occurrence of updrafts in proposed ridge-line wind installations could aid in predicting, and mitigating for, convergence points in raptor migrations.

Global targeting of MDSC escape mechanisms cures advanced 4T1 breast tumors (P2062)

4T1 is a metastatic breast cancer model with fulminant accumulation of MDSCs. Survival and function of MDSCs is often reported as STAT3-dependent, and STAT3 inhibitors such as sunitinib dramatically deplete 4T1 splenic MDSCs. Paradoxically, sunitinib fails to eradicate 4T1 intratumoral MDSCs or prevent tumor progression. We hypothesized that STAT3 activation is a consistent feature of splenic but not intratumoral MDSCs. PhosphoSTAT analyses of 4T1-bearers confirmed that splenic MDSCs of all Gr1 intensities were solely pSTAT3pos. In remarkable contrast, intratumoral Gr1high MDSCs largely lacked any pSTAT activation, and intratumoral Gr1dim MDSC precursors displayed varied expression of pSTAT5 and pSTAT1 in addition to pSTAT3. We therefore sought global means to target MDSCs. We determined that 4T1 and other tumor models could be cured by repetitive administration of cyclophosphamide alternating with TLR agonists such as CpG ODN1826. While cure required participation of host CD4+ and CD8+ T cells, global targeting of MDSCs was also observed: (1) as with sunitinib, pSTAT3pos splenic MDSCs were eradicated; (2) pSTAT expression by intratumoral MDSCs was fully abolished; (3) the remaining intratumoral MDSCs, all pSTATneg, outsurvived all other cells, and were likely induced to serve as the final mediators of tumor rejection. In conclusion, strategies which globally target MDSCs and promote the endogenous anti-tumor T cell response can cure advanced metastatic tumors.

Pharmacodynamic impacts of chemotherapy and immunotherapy upon adipose tissue (P2054)

Recent guidelines by the American Society of Clinical Oncologists recommend that obese individuals receive chemotherapy based on their actual body weight (ABW) without dose reduction. Contrary to prior reports, our own data demonstrate that ABW-dosed chemotherapy or immunotherapy is as effective and well tolerated by obese mice as by lean mice. Nonetheless, obese mice develop significantly greater weight loss in a dose-dependent manner during the entire period that they receive therapy, with corresponding quantifiable reductions in visceral fat depots. This disparity is not explained by altered food intake, as both lean and obese mice experience less than a week of anorexia which does not recur after Cycle 1 of treatment. Furthermore, malabsorption is absent. These observations are relevant to multiple classes of chemo agents. Altered pharmacokinetics of chemotherapy agents in adipose tissue have been reported, yet the pharmacodynamics of obesity remain speculative. Fasting blood glucose monitoring demonstrates glucose level variances which are temporally linked to treatment, rendering it likely that chemotherapy and immunotherapy provoke adipose tissue lipolysis, or alternatively cytoreduction or immunomodulation of adipocyte progenitor cells. Understanding these effects could contribute to improved treatment regimens in the setting of obesity.