ESTRADIOL MODULATION OF THE RENIN ANGIOTENSIN SYSTEM AND THE REGULATION OF FEAR EXTINCTION

Low estradiol levels during extinction training lead to poor extinction consolidation and increased fear during extinction recall; however, the mechanism by which this occurs has not been identified. The renin angiotensin system (RAS), which is often studied in the context of blood pressure regulation and cardiovascular function, has recently been associated with the stress response and stress related pathologies. Antagonists of the angiotensin II type 1 receptor (AT1R), which are commonly prescribed to treat hypertension, reduce symptoms of posttraumatic stress disorder (PTSD) in humans and enhance extinction consolidation in male mice. Since estradiol downregulates many components of the RAS, including AT1R, we hypothesized that estradiol modulates the RAS to affect fear extinction consolidation. We predicted that high estradiol levels during extinction training lead to downregulation of RAS components and enhanced extinction consolidation. We show for the first time that systemic administration of AT1R antagonist losartan prior to extinction training reverses the extinction consolidation deficit found in female rats taking a hormonal contraceptive (HC), which reduces estradiol levels. We also found that female rats that receive ovariectomy (OVX) surgery have a deficit in extinction consolidation compared to sham-operated proestrus females, and that systemic treatment with losartan prior to extinction training rescues the deficit in OVX females. Finally, we explore potential mechanisms for how estradiol is regulating the RAS to affect fear extinction consolidation. While differences in RAS components have been extensively studied in OVX females, no studies have examined how HC treatment affects RAS components or how AT1R levels differ between males and females in the brain. We found that OVX females have increased AT1R ligand binding compared to intact proestrus females in the pituitary gland and ventral subiculum. We also found that HC-treated females have increased circulating angiotensin II (Ang II) peptide levels compared to proestrus females. Our findings have significant clinical implications, suggesting that patients with anxiety disorders such as PTSD should take an AT1R antagonist, especially if they have low estradiol levels, prior to an exposure therapy session to improve treatment outcome

Habitat analysis of a disjunct population of the Carolina northern flying squirrel (Glaucomys sabrinus coloratus)

The northern flying squirrel Glaucomys sabrinus occurs in a variety of forest types over most of North America, with disjunct populations in the southern Appalachians, Black Hills, southern Rocky Mountains, and Sierra Nevada (Wells- Gosling and Heaney, 1984). A subspecies of sabrinus, the Carolina northern flying squirrel, sabrinus coloratus, is a small nocturnal flying squirrel found in the southern Appalachians. One population of Carolina northern flying squirrel occurs within hemlock-northern hardwood forests along the Cherohala Skyway in western North Carolina. This subspecies was listed as federally endangered on July 1, 1985 (U.S. Fish and Wildlife Service, 1990) largely due to declining populations from habitat loss (Loeb et al., 2000). I sought to determine if the larger habitat surrounding the areas of documented squirrel activity is suitable for squirrel persistence, how habitat size and quality compares between sites with squirrel activity and other sites, and what types of foods the squirrels were consuming. Vegetation surveys of sites with documented G. s. coloratus activity, either den sites or capture sites, and paired random sites approximately 70 meters away were conducted. In addition to general habitat knowledge, these surveys provided information for GIS analysis of the larger habitat around the three focal areas. Using ArcGIS v. 9.3.1 (ESRI, Redlands, CA, USA), a model delineating potential Carolina northern flying squirrel habitat based on six parameters: slope, elevation, aspect, spectral signature of den sites, soil types, and tree height data was created. Denaturing gradient gel electrophoresis and sequencing was performed on G. s. coloratus scat samples to determine fungal or bacterial diet composition. Vegetation surveys revealed G. s. coloratus were utilizing habitat from hemlock to northern hardwood forest and habitat patches that were similar to nearby areas along the Cherohala Skyway. The GIS model revealed an area of potential G. s. coloratus habitat to the north (Stratton Bald). Though the distance from Stratton Bald to my three study sites exceeds G. s. coloratus travel distance, the model also revealed an area much closer than Stratton Bald of smaller suitable patches grouped relatively close together. BLAST results of sequenced DGGE bands of squirrel scat revealed similarity to common fungi, including both ascomycetes and basidiomycetes

The Magnetothermal Instability in the Intracluster Medium

The electron mean free path in the intracluster medium (ICM) of galaxy clusters is much larger than the gyroradius; thus, heat is transported anisotropically along magnetic field lines. We show that the intracluster medium is unstable to the magnetothermal instability (MTI) using MHD simulations with anisotropic thermal conduction. As a result of the MTI, we find that the temperature profile of the ICM can be substantially modified on timescales of several billion years while the magnetic field is amplified by dynamo action up to more than fifty times the original energy. We also show that the instability drives field lines to become preferentially radial leading to conduction that is a highly efficient fraction of the Spitzer conductivity. As such, we present the first self-consistent calculation of the effective thermal conductivity in the ICM.Comment: Submitted to Ap

Factors impacting genomic testing rates among epithelial ovarian cancer patients across a large community-based healthcare system

Background: Epithelial ovarian cancer (EOC) accounts for the highest mortality of all gynecological cancers. NCCN guidelines recommend germline and somatic testing for all women with invasive EOC. Despite this recommendation, there is a large diversity in the types of testing patients receive even within a single healthcare system. Reported data of genetic testing for epithelial ovarian cancer (EOC) patients is largely based on patients treated at academic medical centers or patients who participate in clinical trials. Purpose: This study sought to determine the rates of germline and somatic testing for epithelial ovarian cancer patients and identify factors that impact testing rates across a large community-based healthcare system over 5 states: WA, OR, CA, AK, and MT. The system is comprised of over 100,000 caregivers, 51 hospitals and 829 physician clinics. The aim was to identify barriers to testing such as region, hospital type, insurance status, racial/ethnic disparities, and stage of diagnosis. Methods: Clinical, pathologic, demographic and genomic testing information was obtained from the diverse dataset within the Providence St. Joseph Health Electronic Medical Records and the system-wide cancer registry for all patients with an EOC diagnosis (ICD C56.x) between January 2015 and January 2020. Structured genomic data was sourced from laboratory information systems and manual abstraction of molecular sequencing reports. This dataset encompasses patient population data among diverse hospital settings and urban/rural environments. Institution types were broken down into academic setting which contain a residency program (Academic), Commission on Cancer (CoC) accredited programs, or smaller community sites (Community) without CoC accreditation. Descriptive statistics and logical regression are utilized to summarize key findings. Results: Within this EOC cohort (3,007 patients), 34% (n=1,027 patients) completed some type of genomic testing (GT). The percentage of patients tested increased from 31% in 2015 to 46% in 2019, reflecting uptake of testing guidelines. The increase in GT rates was largely attributable to an increase in somatic tumor testing (14-39%); while germline testing rates were stable across the interval (25-33%). Patients were more likely to receive testing if they received care at an academic or CoC institution vs community institution (p=0.0001). Logistic regression analysis demonstrated the following factors impacted tested rates: institution type, insurance, and stage at diagnosis (p=0.001, p= 0.0019 and p \u3c 0.0001, respectively). Race/ethnicity did not contribute significantly to the model but did have a significant effect when analyzed independently. Conclusion: This study is the first to analyze practice patterns in GT for EOC across a broad community-based healthcare system servicing 5 states. The data highlight discrepancies in GT heavily influenced by practice setting, insurance status, and stage of diagnosis (likely reflecting payer coverage/ increased need for information in advanced stage disease). Significance: There is a need for a universally defined approach to testing to provide equitable access to evidence based cancer care. Presenting Author: Nicole Kretzer, MD, PhD, Obstetrics and Gynecology, First Hill Campus, [email protected]

Vagal Stimulation Modulates Inflammation through a Ghrelin Mediated Mechanism in Traumatic Brain Injury

Traumatic brain injury (TBI) releases a cascade of inflammatory cytokines. Vagal nerve stimulation (VNS) and ghrelin have known anti-inflammatory effects; furthermore, ghrelin release is stimulated by acetylcholine. We hypothesized VNS decreases post-TBI inflammation through a ghrelin-mediated mechanism. TBI was created in five groups of mice: sham, TBI, TBI/ghrelin, TBI/VNS, and TBI/VNS/ghrelin receptor antagonist (GRa). Serum and tissue ghrelin, and serum TNF-α were measured. Ghrelin increased following VNS 2 h post-TBI compared to sham or TBI. At 6 h, TBI and TBI/VNS/GRa had increased TNF-α compared to sham while TBI/VNS and TBI/ghrelin had TNF-α level comparable to sham. The highest ghrelin was measured in stomach where TBI decreased ghrelin in contrast to an increase by VNS. In conclusion, VNS increased serum ghrelin and decreased TNF-α following TBI. This was abrogated with GRa. Our data suggests that ghrelin plays an important role in the anti-inflammatory effects of VNS following TBI

A Microtubule Interactome: Complexes with Roles in Cell Cycle and Mitosis

The microtubule (MT) cytoskeleton is required for many aspects of cell function, including the transport of intracellular materials, the maintenance of cell polarity, and the regulation of mitosis. These functions are coordinated by MT-associated proteins (MAPs), which work in concert with each other, binding MTs and altering their properties. We have used a MT cosedimentation assay, combined with 1D and 2D PAGE and mass spectrometry, to identify over 250 MAPs from early Drosophila embryos. We have taken two complementary approaches to analyse the cellular function of novel MAPs isolated using this approach. First, we have carried out an RNA interference (RNAi) screen, identifying 21 previously uncharacterised genes involved in MT organisation. Second, we have undertaken a bioinformatics analysis based on binary protein interaction data to produce putative interaction networks of MAPs. By combining both approaches, we have identified and validated MAP complexes with potentially important roles in cell cycle regulation and mitosis. This study therefore demonstrates that biologically relevant data can be harvested using such a multidisciplinary approach, and identifies new MAPs, many of which appear to be important in cell division