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Protein disulfide isomerase (PDI) is a widely expressed oxidoreductase that catalyzes the rearrangement of intramolecular disulfide bonds during protein maturation in the endoplasmic reticulum. However, PDI can also be secreted from both platelets and endothelial cells during thrombus formation. Inhibition of extracellular PDI in the vasculature using neutralizing antibodies or bacitracin blocks thrombus formation in pre-clinical studies. Our previous experiments identified quercetin-3-rutinoside as an inhibitor of PDI and a potent antithrombotic. Recently, we performed a high-throughput screen of the MLSMR library through the Molecular Libraries Probe Production Centers Network (MLPCN) to identify more potent and selective inhibitors of PDI. We now compare the activity of the most potent lead, ML359, to previously described PDI inhibitors and assess its antithrombotic activity. ML359 inhibited the reductase activity of PDI in the insulin turbidometric assay with an IC50 of 0.3-0.6 microM. By comparison, quercetin-3-rutinoside and juniferdin inhibited PDI with IC50s of 6-10 microM, while bacitracin inhibited PDI reductase activity with an IC50 of 100 microM. ML359 demonstrated no confirmed activity at <10 microM in any of the other of 380 biological assays in which it has been tested within the MLPCN. Additionally, ML359 was selective for PDI, failing to inhibit ERp5, ERp57, ERP72, thioredoxin or thioredoxin reductase activity. Inhibition of PDI by the ML359 was entirely reversible and it did not demonstrate toxicity in a HeLa cell assay. In preparation for pre-clinical studies, further evaluation of the biophysical properties of ML359 was performed. ML359 demonstrated acceptable solubility in PBS, human plasma and GSH. However, it showed poor stability in mouse plasma as well as in presence of liver microsomes. To optimize and improve these biophysical properties of the ML359, over 85 analogs of the lead were synthesized. Modulation of the ethyl substituent of the ester group with bulky isopropyl or t-butyl substituents increased the mouse plasma stability from ∼5% in ML359 to ∼75% and ∼95% in the analogs, respectively. These substitutions only minimally altered the potency of the compound (0.6-0.9 microM). The ML359 analogs demonstrated increased inhibitory activity in platelet aggregation assays, with inhibition at 30 microM increasing from 25% for ML359 to 97 and 100% for the isopropyl and t-butyl substituted analogs, respectively. The ability of ML359 to prevent thrombus formation in a laser injury mouse model was examined. Thrombus formation was monitored following laser injury of cremaster arterioles and the effect of ML359 infusion on platelet accumulation evaluated. ML359 exposure resulted in a significantly smaller thrombus that that observed in the animals infused with vehicle alone. ML359 and its active analogs have enhanced properties compared to the first generation PDI antagonists. These compounds are substantially more potent than previously described PDI inhibitors such as bacitracin and show significant potential as second generation inhibitors to probe PDI function in biological systems. ML359 analogs could ultimately be developed as antithrombotics that target PDI. Disclosures: No relevant conflicts of interest to declare.

Biomass fires can significantly degrade regional air quality. Plume rise height is one of the critical factors determining the impact of fire emissions on air quality. Plume rise models are used to prescribe the vertical distribution of fire emissions which are critical input for smoke dispersion and air quality models. The poor state of model evaluation is due in large part to a lack of appropriate observational datasets. We have initiated a research project to address this critical observation gap. A ground-based, mobile elastic scanning lidar (light detection and ranging) instrument and data-processing methodology have been developed at the Missoula Fire Science Laboratory to study the three-dimensional plume dynamics and the optical properties of smoke particles over large prescribed fires and wildfires. The lidar measurements are being used to validate several plume rise models, including the Briggs equations which are used in VSMOKE and other smoke management tools. We present the validation results and provide recommendations regarding application of the models to wildland fire. IntroductionTightening standards governing air quality have increased the pressure on land management agencies to address the air quality impact of wildland fire use and prescribed burning. Land management agencies need rigorously tested, accurate models to quantify the contribution of fire emissions to air pollution and visibility impairment.Accurately describing and predicting smoke plumes and subsequent smoke transport is a major uncertainty in determining the impact of fire emissions on air quality. While many smoke plume models exist, few smoke plume observational datasets are available to properly validate these models and quantitatively assess their uncertainties, biases, and application limits.We have initiated a research project to acquire the data needed for evaluation of plume rise and smoke dispersion models. The project deploys a ground based, mobile lidar and an airborne instrument package to investigate smoke plume dynamics, smoke aerosol distribution and chemical composition in and around active wildfires and large prescribed fires. Multiple wildland fires have been investigated over a two year period to measure plume rise and smoke transport over a wide range of meteorological, fire activity, fuel, and terrain conditions.We have developed a new lidar data processing technique based on the concept of the Atmospheric Heterogeneity Height Indicator (AHHI) that enables the automatic determination of plume heights and the processing of large volumes of data (Kovalev et al. 2010).

Purpose The objective of this case series is to highlight different manifestations of valacyclovir associated neurotoxicity (VAN) and demonstrate the importance of adjusting medication appropriately in patients with end-stage renal disease (ESRD) on hemodialysis to prevent these complications. Summary Valacyclovir is a medication used to treat herpes zoster infection, commonly known as shingles. Valacyclovir is renally cleared and can accumulate in patients with renal dysfunction leading to severe side effects due to the prolonged half-life. VAN is a common adverse effect in patients with underlying kidney disease, that can be easily prevented if valacyclovir is properly dosed. This case series details the clinical outcomes of two elderly patients who were prescribed valacyclovir at six-times the recommended dose based on their renal function. Failure to reduce the dose of valacyclovir resulted in severe neurological and physical manifestations that required hospital admission and emergent hemodialysis. Conclusion This case series details the importance of adjusting valacyclovir dose based on renal function. In patients with ESRD, the half-life of valacyclovir can be up to 14 hours, therefore hemodialysis should be utilized in severe cases of neurotoxicity to improve rapid excretion of the drug and promote rapid recovery from VAN.