726. APX001 (Fosmanogepix) Is Effective in an Immunosuppressed Mouse Model of Rhizopus oryzae Infection

Background Mucormycosis is a life-threatening infection that predominantly occurs in immunocompromised hosts. The antifungal APX001A (manogepix) inhibits Gwt1, an enzyme required for the conserved glycosylphosphatidyl inositol (GPI) post-translational modification in eukaryotes. We previously reported the activity of APX001 (fosmanogepix, the prodrug of APX001A) against Rhizopus delemar (minimum effective concentration [MEC] = 0.25 µg/mL). Here we assessed the activity against R. oryzae, which has an elevated MEC value. Methods R. oryzae 99–892 MIC and MEC values were 0.125 µg/mL and 4.0 µg/mL for isavuconazole (ISAV) and APX001A, respectively. ICR mice were immunosuppressed with cyclophosphamide (200 mg/kg) and cortisone acetate (500 mg/kg) on Days -2, +3, and +8 relative to intratracheal infection with 2.5 × 105 cells of R. oryzae 99–892. For survival studies, treatment with 104 mg/kg APX001 was compared with ISAV (110 mg/kg TID). Oral treatment started on Day +1 through Day +7, relative to infection for survival studies, and through Day +4 for tissue fungal burden studies (assessed by conidial equivalent [CE] using qPCR). Placebo mice received vehicle control. To extend the half-life of APX001, mice were administered 50 mg/kg of the cytochrome P450 inhibitor 1-aminobenzotriazole (ABT) 2 h prior to APX001 administration. Results APX001 and ISAV equally prolonged median survival time of mice (n = 20) vs. placebo (12 and 14 days for APX001 and ISAV, respectively, vs. 8 days for placebo). Furthermore, APX001 and ISAV treatment both resulted in 30% 21-day survival vs. 0% survival of placebo mice (P < 0.05 by log-rank test). Both drug treatments resulted in ~1.5 log10 reduction in lung and brain CE vs. placebo-treated mice (n = 10, P < 0.005 by Wilcoxon rank-sum test). Conclusion Despite a higher MEC value, APX001 showed significant efficacy against R. oryzae that was as protective as ISAV in immunosuppressed mice. Given the previously reported activity of APX001 against a strain of R. delemar with a lower MEC value,APX001 has now been shown to be efficacious against both species of Rhizopus, which together are responsible for ~60–70% of isolates causing lethal mucormycosis. Thus, continued investigation of APX001 against mucormycosis is warranted. Disclosures All authors: No reported disclosures.

1036. Clinical impact of an antibiotic time out initiative at an academic medical center

Background The Infectious Diseases Society of America’s guideline for implementing antibiotic (abx) stewardship recommends routine review of abx use. Several studies demonstrate antibiotic time out (ATO) programs result in de-escalation, but there is limited evidence of improved outcomes. The aim of this study was to evaluate the clinical impact of ATO. Methods This retrospective study included hospitalized patients at The Ohio State University Wexner Medical Center receiving abx and a documented ATO from 7/1/2017 to 6/30/2018. ATO patients were matched by infection type to abx-treated patients lacking an ATO note. Patients were excluded if they were identified as a protected population, were in the ICU at the time of ATO, had an ATO within 48 hours of discharge, cystic fibrosis, or febrile neutropenia. The primary objective was to evaluate abx optimization in patients with documented ATO vs. those without ATO. Abx optimization was defined as the selection of ideal abx based on guidelines, culture and susceptibility results, or expert opinion when undefined. Secondary outcomes included vancomycin-associated acute kidney injury (VAN-AKI), infection-related length of stay (LOS), all-cause 30-day readmission or mortality, abx days, and nosocomial C. difficile infection (CDI) rates. The Student t-test/Fisher’s exact test and Wilcoxon-rank sum were utilized as appropriate. Results One hundred ATO patients were compared with 100 non-ATO patients. Baseline characteristics and infection types were similar between groups. ATO resulted in improved optimization of abx selection (P = 0.05) and duration (P < 0.01), and reduced piperacillin/tazobactam (P/T) and vancomycin (VAN) utilization. No difference was observed in VAN-AKI (22 vs. 20%, P = 0.73), 30-day readmission (28 vs. 27%, P = 0.87), mortality (5 vs. 5%, P = 1), or CDI rates (6 vs. 5%, p = 0.76) in the ATO vs. non-ATO group. However, inpatient abx days (12 vs. 8, P = 0.004) and infection-related LOS (10 vs. 8, P = 0.0006) were shorter in the non-ATO group. Conclusion ATO improved optimization of abx selection and duration, and reduced P/T and VAN use. Despite this, clinical outcomes were not improved. Disclosures All authors: No reported disclosures.

173. 25-HYDROXYVITAMIN D3 DEFICIENCY AND VITAMIN D RECEPTOR POLYMORPHISMS IN EGYPTIAN BEHÇET’S DISEASE PATIENTS: A PILOT STUDY

Core‐Shell Nanoparticle Probe Scintillation Proximity Assays for Biological Samples

To achieve the overall goal of sensitive and selective radioisotope detection in aqueous samples, we have developed a novel polystyrene‐core silica‐shell nanoparticle scintillator platform (nanoSPA). nanoSPA enabled separation‐free quantification of radiolabeled analytes in complex samples as demonstrated by scintillation proximity assays via protein‐tag, biotin, and antibody binding as well as by other methods such as chemical crosslinking and adsorption. β‐particle emitting radionuclides such as 3 H, 33 P, and 35 S are useful molecular labels due to their small size but are challenging to detect and quantify with spatial and temporal resolution in biological samples due to their low energies (E max ≤ 300 keV) and short penetration depths (≤ 0.6 mm). Activity measurements for these β‐emitters are usually made in milliliter volumes of liquid scintillation cocktail (LSC), a mixture of energy‐absorbing organic solvents, surfactants, and scintillant fluorophores, which is incompatible with living cells and dynamic biological measurements. Alternatively, solid polymer or inorganic crystals can be used, but the orientation of polymer sheets, the large size of polymer particles (> 2μm) and the high density of inorganic scintillators can result in inaccurate counting. nanoSPA avoids the toxicity of LSC as well as many of the limitations of polymer and inorganic crystal scintillators. The polystyrene acts as an absorber for energy from emitted β‐particles and is loaded with scintillant fluorophores to which the energy is transferred, leading to photon emission at visible wavelengths. The silica shell serves as a hydrophilic shield for the polystyrene core and facilitates functionalization with specific binding molecules for scintillation proximity assays. In this way, the short penetration depths of low‐energy β‐particles are used advantageously, as radiolabeled analytes that are not close enough to the nanoparticle surface (primarily bound to the surface during an assay) are less likely to be detected, resulting in low background signal. Selectivity was determined to be up to 30 times greater for bound 3 H‐analytes over unbound 3 H analytes when the labeled species was covalently bound to nanoSPA, 18 times greater for antibody functionalized nanoSPA, 8 times greater for biotin functionalized nanoSPA, and 4 times greater for ssDNA functionalized nanoSPA. We have also measured and monitored peptide phosphorylation with kinase and 33 P ɣ ‐ ATP. nanoSPA not only facilitates measurement of radiolabeled analytes in bulk aqueous solutions, but due to the small diameter and the protection of the hydrophobic polymer core by the silica shell, nanoSPA particles could potentially be used as cellular or intracellular imaging probes. Support or Funding Information This work was supported in part by the National Science Foundation under grant number 1807343, the National Institutes of Health via the National Institute of Biomedical Imaging and Bioengineering under grant number R21EB019133 and the National Institute of General Medical Sciences under grant number 1R01GM116946. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

Sigma‐1 receptor agonists elicit arteriolar dilation via Akt/eNOS activation, and also have endothelial barrier protective properties

Sigma‐1 receptors (σ1) have previously gained considerable attention pertaining to neuroprotection through its actions on calcium homeostasis, and the mitochondria‐associated ER membrane domain. Our laboratory recently showed that the σ1 agonist afobazole causes an endothelial NO‐dependent decrease in contraction amplitude. However, little is known about the mechanisms and functions of σ1 receptor in endothelial cells. In the current study, we investigated how σ1 agonists impact brain arteriolar tone and the Akt/eNOS pathway. Parenchymal arterioles were isolated from brains of Sprague‐Dawley rats and mounted onto glass micropipettes in a 37 °C bath containing albumin‐physiological salt solution. The nonselective σ agonist afobazole was applied to the bath at concentrations of 50, 100, 150, 200, and 250 μM in the presence or absence of the σ1 antagonist BD1047. The selective σ1 agonist, PRE‐084 was used to stimulate human umbilical vein endothelial cells (HUVEC), in which phosphorylation of endothelial NO synthase (eNOS) or Akt phosphorylation on their activation sites (S1177 and S473, respectively) were evaluated by western blotting. NO production was measured by fluorescence microscopy in cells loaded with the indicator dye DAF‐FM. Trans‐endothelial electrical resistance (TER) was used to determine the ability of PRE‐084 to attenuate disruption of endothelial barrier function caused by the the mitochondrial function inhibitors CCCP and antimycin‐A, or the inflammatory cytokine IL‐1β. The results show that afobazole significantly dilated rat brain arterioles, which was inhibited by the σ1 antagonist BD‐1047. Selective activation of σ1 with PRE‐084 significantly increased eNOS phosphorylation on S1177 and this was diminished in the presence of BD‐1047. Akt phosphorylation on S473 following PRE‐084 treatment was also enhanced. In addition, afobazole and PRE‐084 enhanced NO production in endothelial cells. PRE‐084 significantly attenuated decreases in TER caused by IL‐1β or CCCP, but not antimycin‐A, suggesting a potential barrier‐protective role for σ1 receptor, with some limitations that may be related to the source of mitochondrial dysfunction during inflammation. Collectively, our results suggest that σ1 receptor activation can cause vasodilation via the Akt/eNOS pathway in endothelial cells, and that σ1 may enhance endothelial barrier function under inflammatory conditions. Support or Funding Information Supported by NIH grant R01GM120774. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

Galectin‐3 Levels in Hepatic Tissue from Lean and Obese Zucker Rats

Obesity and metabolic syndrome are of major concern for physicians worldwide. Galectin‐3 is a β‐galactoside‐binding protein that has been shown to have regulatory functions in inflammatory responses as well as fibrosis of the liver, lung, heart and blood vessels. Galectin‐3 is widely expressed in multiple types of immune cells as well as epithelial and endothelial cells, and its properties have been explored as a therapeutic target for nonalcoholic fatty liver disease liver fibrosis, heart disease and other obesity‐associated diseases. We previously observed elevation of galectin‐3 in mesenteric fat from male and female 12‐week‐old obese Zucker rats compared to their lean counterparts. We hypothesized that galectin‐3 expression levels would be elevated in the liver in obese animals. Livers were collected from 20 Zucker rats (5 male, 5 female lean rats and 5 male, 5 female obese Zucker rats) for histology and protein analysis. After protein lysates were collected and total protein levels were normalized, galectin‐3 levels were quantified with the Wes Simple Western capillary electrophoresis assay. The results showed that livers of obese rats of both sexes display typical fatty liver pathology and have a significantly higher level of Galectin‐3 expression. The results show that increased galectin‐3 expression accompanies fatty liver in obese rats. Galectin‐3 may represent a future target for preventing tissue dysfunction in obesity and metabolic syndrome Support or Funding Information APS Frontiers in Physiology Fellowship This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

EFFECTS OF BLOOD PRESSURE LOWERING DRUGS IN HEART FAILURE

We aimed to combine evidence from all heart failure trials that have investigated the effects of drugs with blood pressure lowering properties to assess (1) the extent to which such drugs reduce blood pressure in heart failure, (2) the association between the net change in blood pressure between treatment arms and cause‐specific outcomes, and (3) whether treatment effects (efficacy and safety) vary according to baseline blood pressure. We conducted a systematic review and meta‐analysis including randomised clinical trials of drugs with blood pressure‐lowering properties in patients with chronic heart failure with at least 300 patient‐ years follow‐up. We included a total of 37 trials (91,950 patients) and showed that treatment with drugs with blood pressure‐lowering properties resulted in a small but significant decrease in systolic blood pressure in patients with heart failure with no evidence that the efficacy and safety of those drugs varied according to baseline blood pressure. Condensed abstract The relationship between blood pressure and clinical outcomes remains poorly understood. This systematic review and meta‐analysis combined evidence from randomised clinical trials of drugs with blood pressure lowering properties in patients with chronic heart failure. It showed that treatment with those drugs achieved a small but significant reduction in systolic blood pressure with no evidence that the efficacy and safety of those drugs varied according to baseline blood pressure.

Effects of blood pressure-lowering drugs in heart failure

: We aimed to combine evidence from all heart failure trials that have investigated the effects of drugs with blood pressure (BP)-lowering properties to assess the extent to which such drugs reduce BP in heart failure, the association between the net change in BP between treatment arms and cause-specific outcomes and whether treatment effects (efficacy and safety) vary according to baseline BP. We conducted a systematic review and meta-analysis including randomized clinical trials of drugs with BP-lowering properties in patients with chronic heart failure with at least 300 patient-years follow-up. We included a total of 37 trials (91 950 patients) and showed that treatment with drugs with BP-lowering properties resulted in a small but significant decrease in SBP in patients with heart failure with no evidence that the efficacy and safety of those drugs varied according to baseline BP.

Methodology for tDCS integration with fMRI

Temporal interference stimulation targets deep brain regions by modulating neural oscillations