Kinetics and Inhibition Studies of the L205R Mutant of cAMP-Dependent Protein Kinase Involved in Cushing’s Syndrome

Overproduction of cortisol by the hypothalamus–pituitary–adrenal hormone system results in the clinical disorder known as Cushing\u27s syndrome. Genomics studies have identified a key mutation (L205R) in the α‐isoform of the catalytic subunit of cAMP‐dependent protein kinase (PKACα) in adrenal adenomas of patients with adrenocorticotropic hormone‐independent Cushing\u27s syndrome. Here, we conducted kinetics and inhibition studies on the L205R‐PKACα mutant. We have found that the L205R mutation affects the kinetics of both Kemptide and ATP as substrates, decreasing the catalytic efficiency (kcat/KM) for each substrate by 12‐fold and 4.5‐fold, respectively. We have also determined the IC50 and Ki for the peptide substrate‐competitive inhibitor PKI(5–24) and the ATP‐competitive inhibitor H89. The L205R mutation had no effect on the potency of H89, but causes a \u3e 250‐fold loss in potency for PKI(5–24). Collectively, these data provide insights for the development of L205R‐PKACα inhibitors as potential therapeutics

Assessment of contemporary Arctic river runoff based on observational discharge records

We describe the contemporary hydrography of the pan‐Arctic land area draining into the Arctic Ocean, northern Bering Sea, and Hudson Bay on the basis of observational records of river discharge and computed runoff. The Regional Arctic Hydrographic Network data set, R‐ArcticNET, is presented, which is based on 3754 recording stations drawn from Russian, Canadian, European, and U.S. archives. R‐ArcticNET represents the single largest data compendium of observed discharge in the Arctic. Approximately 73% of the nonglaciated area of the pan‐Arctic is monitored by at least one river discharge gage giving a mean gage density of 168 gages per 106 km2. Average annual runoff is 212 mm yr−1 with approximately 60% of the river discharge occurring from April to July. Gridded runoff surfaces are generated for the gaged portion of the pan‐Arctic region to investigate global change signals. Siberia and Alaska showed increases in winter runoff during the 1980s relative to the 1960s and 1970s during annual and seasonal periods. These changes are consistent with observations of change in the climatology of the region. Western Canada experienced decreased spring and summer runoff

Flux of nutrients from Russian rivers to the Arctic Ocean: Can we establish a baseline against which to judge future changes?

Climate models predict significant warming in the Arctic in the 21st century, which will impact the functioning of terrestrial and aquatic ecosystems as well as alter land‐ocean interactions in the Arctic. Because river discharge and nutrient flux integrate large‐scale processes, they should be sensitive indicators of change, but detection of future changes requires knowledge of current conditions. Our objective in this paper is to evaluate the current state of affairs with respect to estimating nutrient flux to the Arctic Ocean from Russian rivers. To this end we provide estimates of contemporary (1970s–1990s) nitrate, ammonium, and phosphate fluxes to the Arctic Ocean for 15 large Russian rivers. We rely primarily on the extensive data archives of the former Soviet Union and current Russian Federation and compare these values to other estimates and to model predictions. Large discrepancies exist among the various estimates. These uncertainties must be resolved so that the scientific community will have reliable data with which to calibrate Arctic biogeochemical models and so that we will have a baseline against which to judge future changes (either natural or anthropogenic) in the Arctic watershed

On the size of the Fe II emitting region in the AGN Akn 120

We present a reverberation analysis of the strong, variable optical Fe II emission bands in the spectrum of Akn 120, a low-redshift AGN which is one of the best candidates for such a study. On time scales of several years the Fe II line strengths follow the variations in the continuum strength. However, we are unable to measure a clear reverberation lag time for these Fe II lines on any time scale. This is due to the very broad and flat-topped nature of the Fe II cross correlation functions, as compared to the H-beta response which is much more sharply localized in time. Although there is some suggestion in the light curve of a 300-day response time, our statistical analysis does not pick up such a feature. We conclude that the optical Fe II emission does not come from a photoionization-powered region similar in size to the H-beta emitting region, but we cannot say for sure where it does come from. Our results are generally consistent either with emission from a photoionized region several times larger than the H-beta zone, or with emission from gas heated by some other means, perhaps responding only indirectly to the continuum variations.Comment: Accepted for publication in the Ap

Separation of river network–scale nitrogen removal among the main channel and two transient storage compartments

Transient storage (TS) zones are important areas of dissolved inorganic nitrogen (DIN) processing in rivers. We assessed sensitivities regarding the relative impact that the main channel (MC), surface TS (STS), and hyporheic TS (HTS) have on network denitrification using a model applied to the Ipswich River in Massachusetts, United States. STS and HTS connectivity and size were parameterized using the results of in situ solute tracer studies in first‐ through fifth‐order reaches. DIN removal was simulated in all compartments for every river grid cell using reactivity derived from Lotic Intersite Nitrogen Experiment (LINX2) studies, hydraulic characteristics, and simulated discharge. Model results suggest that although MC‐to‐STS connectivity is greater than MC‐to‐HTS connectivity at the reach scale, at basin scales, there is a high probability of water entering the HTS at some point along its flow path through the river network. Assuming our best empirical estimates of hydraulic parameters and reactivity, the MC, HTS, and STS removed approximately 38%, 21%, and 14% of total DIN inputs during a typical base flow period, respectively. There is considerable uncertainty in many of the parameters, particularly the estimates of reaction rates in the different compartments. Using sensitivity analyses, we found that the size of TS is more important for DIN removal processes than its connectivity with the MC when reactivity is low to moderate, whereas TS connectivity is more important when reaction rates are rapid. Our work suggests a network perspective is needed to understand how connectivity, residence times, and reactivity interact to influence DIN processing in hierarchical river systems

Skeletonization of bilateral internal thoracic artery grafts lowers the risk of sternal infection in patients with diabetes

AbstractObjectiveDeep sternal wound infection is a dreaded complication of coronary artery bypass surgery, particularly in patients with diabetes. This study determines whether skeletonization of internal thoracic artery conduits compared with pedicled harvesting reduces the risk of deep sternal wound infection in patients with diabetes undergoing bilateral internal thoracic artery grafting.MethodsWe reviewed prospectively gathered data on all patients who have undergone coronary artery bypass grafting and received bilateral internal thoracic artery grafts at our institution since 1990. We compared patients with diabetes who received skeletonized (n = 79) versus conventional pedicled (n = 36) internal thoracic artery conduits.ResultsThe proportion of patients taking insulin (19.0% vs 14.0% for skeletonized vs conventional grafts, respectively, P = .6) or oral hypoglycemic agents (68.4% vs 69.4%, P = .9), as well as the prevalence of type I diabetes (2.5% vs 8.3%, P = .18), were similar in both groups. Patients who received skeletonized grafts were more likely to receive a free rather than an in situ right internal thoracic artery graft (93.7% vs 30.6%, P < .001). The prevalence of deep sternal wound infection was significantly lower in patients who received skeletonized grafts compared with patients who received conventional grafts (1.3% vs 11.1%, P = .03). Patients in the skeletonized group were also less likely to develop any (superficial or deep) sternal wound infection postoperatively (5.1% vs 22.2%, P = .03). There was no significant difference in the prevalence of deep sternal wound infection between patients with diabetes who received skeletonized internal thoracic arteries and patients without diabetes who underwent conventional internal thoracic artery grafting (n = 578) (1.2% vs 1.6%, respectively, P = .8).ConclusionsSkeletonization of internal thoracic artery conduits lowers the risk of deep sternal wound infection in patients with diabetes undergoing bilateral internal thoracic artery grafting. We no longer consider diabetes a contraindication to bilateral internal thoracic artery grafting, provided the internal thoracic arteries are skeletonized

Impact of COVID-19 Pandemic on Pharmacy Teaching at a Midwestern University

The coronavirus (COVID-19) pandemic severely impacted higher education institutions. In March 2020, the North Dakota State University School of Pharmacy notified faculty and students that the remainder of the semester would be taught using remote learning. The study objective is to determine how the change from the traditional classroom to remote learning impacted students and faculty. Pharmacy students were surveyed to ascertain how the transition to remote learning have impacted their learning. Additionally, faculty were surveyed using a semi-structured interview to assess their instructional efforts. The student survey findings identify several challenges impacting instruction, including online exam-taking and balancing time constraints. Faculty survey responses collected include themes of decreased student engagement, technology use and access, and transitions in the learning environment. Curriculum areas facing significant challenges during the pandemic include hands-on laboratory skills and experiential education which required multiple changes. Despite the challenges, faculty made the teaching transitions that they might not have otherwise tried. Assessing the impact of remote learning will continue to be important as the pandemic continues

Supermassive Black Holes in Active Galactic Nuclei. I. The Consistency of Black Hole Masses in Quiescent and Active Galaxies

We report the first results of a program to measure accurate stellar velocity dispersions in the bulges of the host galaxies of active galactic nuclei (AGNs) for which accurate black hole (BH) masses have been determined via reverberation mapping. We find good agreement between BH masses obtained from reverberation mapping, and from the M(BH) - sigma relation as defined by quiescent galaxies, indicating a common relationship between active and quiescent black holes and their large-scale environments.Comment: Submitted to ApJ

Potential net primary productivity in South America: application of a global model

We use a mechanistically based ecosystem simulation model to describe and analyze the spatial and temporal patterns of terrestrial net primary productivity (NPP) in South America. The Terrestrial Ecosystem Model (TEM) is designed to predict major carbon and nitrogen fluxes and pool sizes in terrestrial ecosystems at continental to global scales. Information from intensively studies field sites is used in combination with continental—scale information on climate, soils, and vegetation to estimate NPP in each of 5888 non—wetland, 0.5° latitude °0.5° longitude grid cells in South America, at monthly time steps. Preliminary analyses are presented for the scenario of natural vegetation throughout the continent, as a prelude to evaluating human impacts on terrestrial NPP. The potential annual NPP of South America is estimated to be 12.5 Pg/yr of carbon (26.3 Pg/yr of organic matter) in a non—wetland area of 17.0 ° 106 km2. More than 50% of this production occurs in the tropical and subtropical evergreen forest region. Six independent model runs, each based on an independently derived set of model parameters, generated mean annual NPP estimates for the tropical evergreen forest region ranging from 900 to 1510 g°m—2°yr—1 of carbon, with an overall mean of 1170 g°m—2°yr—1. Coefficients of variation in estimated annual NPP averaged 20% for any specific location in the evergreen forests, which is probably within the confidence limits of extant NPP measurements. Predicted rates of mean annual NPP in other types of vegetation ranged from 95 g°m—2°yr—1 in arid shrublands to 930 g°m@?yr—1 in savannas, and were within the ranges measured in empirical studies. The spatial distribution of predicted NPP was directly compared with estimates made using the Miami mode of Lieth (1975). Overall, TEM predictions were °10% lower than those of the Miami model, but the two models agreed closely on the spatial patterns of NPP in south America. Unlike previous models, however, TEM estimates NPP monthly, allowing for the evaluation of seasonal phenomena. This is an important step toward integration of ecosystem models with remotely sensed information, global climate models, and atmospheric transport models, all of which are evaluated at comparable spatial and temporal scales. Seasonal patterns of NPP in South America are correlated with moisture availability in most vegetation types, but are strongly influenced by seasonal differences in cloudiness in the tropical evergreen forests. On an annual basis, moisture availability was the factor that was correlated most strongly with annual NPP in South America, but differences were again observed among vegetation types. These results allow for the investigation and analysis of climatic controls over NPP at continental scales, within and among vegetation types, and within years. Further model validation is needed. Nevertheless, the ability to investigate NPP—environment interactions with a high spatial and temporal resolution at continental scales should prove useful if not essential for rigorous analysis of the potential effects of global climate changes on terrestrial ecosystems

Caregiver reactions to neuroimaging evidence of covert consciousness in patients with severe brain injury: a qualitative interview study

Background: Severe brain injury is a leading cause of death and disability. Diagnosis and prognostication are difficult, and errors occur often. Novel neuroimaging methods can improve diagnostic and prognostic accuracy, especially in patients with prolonged disorders of consciousness (PDoC). Yet it is currently unknown how family caregivers understand this information, raising ethical concerns that disclosure of neuroimaging results could result in therapeutic misconception or false hope. Methods: To examine these ethical concerns, we conducted semi-structured interviews with caregivers of patients with PDoC who were enrolled in a concurrent neuroimaging research program designed to detect covert consciousness following severe brain injury. Caregivers held surrogate decision-making status for a patient. Interviews were conducted at two time points for each caregiver. The first interview occurred before the disclosure of neuroimaging results. The second occurred after disclosure. Descriptive analysis was applied to the data of four interview topics: (1) expectations for neuroimaging; (2) reactions to evidence of preserved cognition; (3) reactions to null results; and (4) understanding of the results and study. Results: Twelve caregivers participated in the study; two caregivers shared surrogate decision-making status for one patient with PDoC. Twenty-one interviews were completed; one caregiver declined to participate in the post-disclosure interview. Three patients with PDoC associated with the study displayed evidence of covert consciousness. Overall, caregivers understood the neuroimaging research and results. Caregivers who received results of covert consciousness were generally pleased. However, there was some variation in expectations and reactions to these data and null results. Conclusion: This study, for the first time, reveals caregiver expectations for and reactions to neuroimaging evidence of covert consciousness in patients with PDoC. Caregivers understood the neuroimaging research and results, casting doubt on speculative ethical concerns regarding therapeutic misconception and false hope. However, disclosure of neuroimaging result could be improved. Pre-disclosure consultations might assist professionals in shaping caregiver expectations. Standardization of disclosure might also improve comprehension of the results