Publications by authors named "C Broch Woodson"

32 Publications

Variable coastal hypoxia exposure and drivers across the southern California Current.

Sci Rep 2021 05 25;11(1):10929. Epub 2021 May 25.

COBIA Lab, University of Georgia, Athens, GA, USA.

Declining oxygen is one of the most drastic changes in the ocean, and this trend is expected to worsen under future climate change scenarios. Spatial variability in dissolved oxygen dynamics and hypoxia exposures can drive differences in vulnerabilities of coastal ecosystems and resources, but documentation of variability at regional scales is rare in open-coast systems. Using a regional collaborative network of dissolved oxygen and temperature sensors maintained by scientists and fishing cooperatives from California, USA, and Baja California, Mexico, we characterize spatial and temporal variability in dissolved oxygen and seawater temperature dynamics in kelp forest ecosystems across 13° of latitude in the productive California Current upwelling system. We find distinct latitudinal patterns of hypoxia exposure and evidence for upwelling and respiration as regional drivers of oxygen dynamics, as well as more localized effects. This regional and small-scale spatial variability in dissolved oxygen dynamics supports the use of adaptive management at local scales, and highlights the value of collaborative, large-scale coastal monitoring networks for informing effective adaptation strategies for coastal communities and fisheries in a changing climate.
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http://dx.doi.org/10.1038/s41598-021-89928-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8149850PMC
May 2021

Murine- and Human-Derived Autologous Organoid/Immune Cell Co-Cultures as Pre-Clinical Models of Pancreatic Ductal Adenocarcinoma.

Cancers (Basel) 2020 Dec 17;12(12). Epub 2020 Dec 17.

Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85719, USA.

: Pancreatic ductal adenocarcinoma (PDAC) has the lowest five-year survival rate of all cancers in the United States. Programmed death 1 receptor (PD-1)-programmed death ligand 1 (PD-L1) immune checkpoint inhibition has been unsuccessful in clinical trials. Myeloid-derived suppressor cells (MDSCs) are known to block anti-tumor CD8+ T cell immune responses in various cancers including pancreas. This has led us to our objective that was to develop a clinically relevant in vitro organoid model to specifically target mechanisms that deplete MDSCs as a therapeutic strategy for PDAC. : Murine and human pancreatic ductal adenocarcinoma (PDAC) autologous organoid/immune cell co-cultures were used to test whether PDAC can be effectively treated with combinatorial therapy involving PD-1 inhibition and MDSC depletion. : Murine in vivo orthotopic and in vitro organoid/immune cell co-culture models demonstrated that polymorphonuclear (PMN)-MDSCs promoted tumor growth and suppressed cytotoxic T lymphocyte (CTL) proliferation, leading to diminished efficacy of checkpoint inhibition. Mouse- and human-derived organoid/immune cell co-cultures revealed that PD-L1-expressing organoids were unresponsive to nivolumab in vitro in the presence of PMN-MDSCs. Depletion of arginase 1-expressing PMN-MDSCs within these co-cultures rendered the organoids susceptible to anti-PD-1/PD-L1-induced cancer cell death. : Here we use mouse- and human-derived autologous pancreatic cancer organoid/immune cell co-cultures to demonstrate that elevated infiltration of polymorphonuclear (PMN)-MDSCs within the PDAC tumor microenvironment inhibit T cell effector function, regardless of PD-1/PD-L1 inhibition. We present a pre-clinical model that may predict the efficacy of targeted therapies to improve the outcome of patients with this aggressive and otherwise unpredictable malignancy.
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http://dx.doi.org/10.3390/cancers12123816DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7766822PMC
December 2020

A Nonrandomized Trial of Prolonged Exposure and Cognitive Processing Therapy for Combat-Related Posttraumatic Stress Disorder in a Deployed Setting.

Behav Ther 2020 11 13;51(6):882-894. Epub 2020 Jan 13.

University of Texas Health Science Center at San Antonio.

For many decades, the U.S. military's general operational guideline has been to limit the use of trauma-focused treatments for combat and operational stress reactions in military service members until they have returned from deployment. Recently, published clinical trials have documented that active-duty military personnel with combat-related posttraumatic stress disorder (PTSD) can be treated effectively in garrison. However, there are limited data on the treatment of combat and operational stress reactions or combat-related PTSD during military deployments. This prospective, nonrandomized trial evaluated the treatment of active-duty service members (N = 12) with combat and operational stress reactions or combat-related PTSD while deployed to Afghanistan or Iraq. Service members were treated by deployed military behavioral health providers using modified Prolonged Exposure (PE; n = 6) or modified Cognitive Processing Therapy (CPT; n = 6), with protocol modifications tailored to individual mission requirements. The PTSD Checklist-Military Version (PCL-M) total score was the primary outcome measure. Results indicated that both groups demonstrated clinically significant change in PTSD symptoms as indicated by a reduction of 10 points or greater on the PCL-M. Participants treated with modified PE had significant reductions in PTSD symptoms, t = -3.83, p = .01; g = -1.32, with a mean reduction of 18.17 points on the PCL-M. Participants treated with modified CPT had a mean PCL-M reduction of 10.00 points, but these reductions were not statistically significant, t = -1.49, p = .12; g = -0.51. These findings provide preliminary evidence that modified forms of PE and CPT can be implemented in deployed settings for the treatment of combat and operational stress reactions and combat-related PTSD.
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http://dx.doi.org/10.1016/j.beth.2020.01.003DOI Listing
November 2020

Geographic variation in responses of kelp forest communities of the California Current to recent climatic changes.

Glob Chang Biol 2020 Nov 9;26(11):6457-6473. Epub 2020 Sep 9.

Universidad Autónoma de Baja California, Ensenada, Mexico.

The changing global climate is having profound effects on coastal marine ecosystems around the world. Structure, functioning, and resilience, however, can vary geographically, depending on species composition, local oceanographic forcing, and other pressures from human activities and use. Understanding ecological responses to environmental change and predicting changes in the structure and functioning of whole ecosystems require large-scale, long-term studies, yet most studies trade spatial extent for temporal duration. We address this shortfall by integrating multiple long-term kelp forest monitoring datasets to evaluate biogeographic patterns and rates of change of key functional groups (FG) along the west coast of North America. Analysis of data from 469 sites spanning Alaska, USA, to Baja California, Mexico, and 373 species (assigned to 18 FG) reveals regional variation in responses to both long-term (2006-2016) change and a recent marine heatwave (2014-2016) associated with two atmospheric and oceanographic anomalies, the "Blob" and extreme El Niño Southern Oscillation (ENSO). Canopy-forming kelps appeared most sensitive to warming throughout their range. Other FGs varied in their responses among trophic levels, ecoregions, and in their sensitivity to heatwaves. Changes in community structure were most evident within the southern and northern California ecoregions, while communities in the center of the range were more resilient. We report a poleward shift in abundance of some key FGs. These results reveal major, ongoing region-wide changes in productive coastal marine ecosystems in response to large-scale climate variability, and the potential loss of foundation species. In particular, our results suggest that coastal communities that are dependent on kelp forests will be more impacted in the southern portion of the California Current region, highlighting the urgency of implementing adaptive strategies to sustain livelihoods and ensure food security. The results also highlight the value of multiregional integration and coordination of monitoring programs for improving our understanding of marine ecosystems, with the goal of informing policy and resource management in the future.
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http://dx.doi.org/10.1111/gcb.15273DOI Listing
November 2020

Food web complexity weakens size-based constraints on the pyramids of life.

Proc Biol Sci 2020 09 9;287(1934):20201500. Epub 2020 Sep 9.

Department of Marine Sciences, University of Georgia, Athens, GA 30602, USA.

Marine ecosystems are generally expected to have bottom-heavy trophic structure (more plants than animals) due to size-based constraints arising from increased metabolic requirements and inefficient energy transfer. However, size-based (allometric) approaches are often limited to confined trophic-level windows where energy transfer is predicted by size alone and are constrained to a balance between bottom-up and top-down control at steady state. In real food webs, energy flow is more complex and imbalances in top-down and bottom-up processes can also shape trophic structure. We expand the size-based theory to account for complex food webs and show that moderate levels of food web connectance allow for inverted trophic structure more often than predicted, especially in marine ecosystems. Trophic structure inversion occurs due to the incorporation of complex energy pathways and top-down effects on ecosystems. Our results suggest that marine ecosystems should be top-heavy, and observed bottom-heavy trophic structure may be a result of human defaunation of the ocean that has been more extreme than presently recognized.
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http://dx.doi.org/10.1098/rspb.2020.1500DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7542787PMC
September 2020
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