A key metabolic adaptation of some species that face hypoxia as part of their life cycle involves an alternative electron transport chain in which rhodoquinone (RQ) is required for fumarate reduction and ATP production. RQ biosynthesis in bacteria and protists requires ubiquinone (Q) as a precursor. In contrast, Q is not a precursor for RQ biosynthesis in animals such as parasitic helminths, and most details of this pathway have remained elusive. Here, we used Caenorhabditis elegans as a model animal to elucidate key steps in RQ biosynthesis. Using RNAi and a series of C. elegans mutants, we found that arylamine metabolites from the kynurenine pathway are essential precursors for RQ biosynthesis de novo. Deletion of kynu-1, encoding a kynureninase that converts l-kynurenine (KYN) to anthranilic acid (AA) and 3-hydroxykynurenine (3HKYN) to 3-hydroxyanthranilic acid (3HAA), completely abolished RQ biosynthesis but did not affect Q levels. Deletion of kmo-1, which encodes a kynurenine 3-monooxygenase that converts KYN to 3HKYN, drastically reduced RQ but not Q levels. Knockdown of the Q biosynthetic genes coq-5 and coq-6 affected both Q and RQ levels, indicating that both biosynthetic pathways share common enzymes. Our study reveals that two pathways for RQ biosynthesis have independently evolved. Unlike in bacteria, where amination is the last step in RQ biosynthesis, in worms the pathway begins with the arylamine precursor AA or 3HAA. Because RQ is absent in mammalian hosts of helminths, inhibition of RQ biosynthesis may have potential utility for targeting parasitic infections that cause important neglected tropical diseases.

Background: Cerebrovascular disease, particularly overt stroke, is one of the most critical clinical complications of sickle cell disease (SCD). Individual stroke risk for patients with SCD is assessed by measuring trans-cranial Doppler ultrasound (TCD) velocity. While TCD screening and resulting use of chronic blood transfusion therapy in patients with abnormal TCDs has reduced stroke incidence in patients with SCD from 11% to 1%, the test has significant limitations. It can only be performed on children old enough to remain still for the assessment, or young enough to have open bony windows; typically 2-16 years of age. Additionally the test has poor positive predictive value, causing patients to be placed on chronic transfusion therapy who would not have gone on to have a stroke. Hydroxyurea (HU) is replacing chronic transfusion therapy in many institutions for primary stroke prevention, but many sites initiate a "cooling off" period of transfusions prior to initiating HU, and transfusion therapy may be indicated for abnormal TCD velocities in patients already on HU. The pathophysiology of stroke in SCD patients is not completely understood, but vascular remodeling, abnormal cerebral blood flow, and vaso-occlusion all play a role. Plasma levels of Brain derived neurotrophic factor (BDNF), myeloperoxidase (MPO), vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) have been shown to be associated with high trans-cranial Doppler ultrasound (TCD) velocity in children with SCD; but there is limited data on their potential association with stroke in this population. BDNF is a neurotropin that is responsive to hypoxia and promotes neurogenesis as well as playing a key role in the regulation of the cell survival pathway; myeloperoxidase (MPO) promotes vascular injury by oxygen radical generation, leukocyte/neutrophil recruitment, and oxidative stress; vascular cell adhesion molecule 1 (VCAM-1) is and endothelial adhesion molecule involved in the pathophysiology of vaso-occlusion in SCD through promoting RBC adhesion; and intercellular adhesion molecule 1 (ICAM-1) is expressed on endothelial and immune system cells and is thought to be a ligand for leukocyte adhesion. We hypothesized that BDNF, MPO, VCAM-1 and ICAM-1 may be involved in stroke in SCD, and may be potential biomarkers to be used to assess an individual with SCD's stroke risk in addition to TCD. Methods: We collected plasma samples from the peripheral blood of fifteen SCD patients (HbSS) at the time of either silent cerebral infarct (SCI) or stroke. Stroke (n=8) or SI was confirmed by MRI using diffusion imaging and T2 FLAIR. The cohort included 6 females and 9 males between the ages of 3 and 20 years. Plasma from fifteen age and gender matched control patients with HbSS but had normal MRIs and TCD velocities less than 170 m/s. We measured plasma levels of BDNF, MPO, VCAM-1 and ICAM-1 using antibody immobilized fluorescent beads (Millipore, Billerica, MA) and Luminex xMAP technology (Bio-Rad, Hercules, CA). Student's t-test was used to analyze the difference in plasma levels between the stroke and control groups. Results and Conclusions: BDNF levels were significantly higher in the stroke group than in the control group; 2978.2 ± 960.3 pg/ml compared to 2200.8 ± 758.4 pg/ml, p=0.005. Difference in MPO levels between the two groups approached significance; 36617.2 ± 14828.9 pg/ml compared to 29521.9 ± 7889.6 pg/ml, p=0.07. Difference in VCAM-1 levels also approached significance; 143997.0 ± 9963.8 pg/ml compared to 138126.9 ± 11902.0 pg/ml, p=0.08, but there was no significant difference in ICAM-1 levels. Only BDNF plasma levels positively correlated with the area and volume of the infarct, p=0.009. These results further support the assertion that BDNF is involved in the pathophysiology of cerebrovascular disease in SCD. It is possible that MPO and VCAM-1 may also play a role, and that a significant difference was not found due to sample size limitations. Plasma BDNF levels, and possibly MPO and VCAM-1 plasma levels, have potential as biomarkers for stroke risk to improve the positive predictive value of TCD velocities in patients with SCD, or to assess risk in patients unable to receive TCDs. Disclosures No relevant conflicts of interest to declare.

Introduction:This study aims to determine the differences between urological consulting service utilization in an academic setting compared to a private setting at a single institution during its transition from private to academic medical center.Methods:A retrospective review of patients undergoing inpatient urology consultation from July 2014 to June 2019 was performed. Consults were weighted using patient-days to account for hospital census.Results:A total of 1,882 inpatient urology consults were ordered, with 763 occurring prior to and 1,187 occurring after transition to academic medical center. Consults were placed more frequently in the academic than private setting (6.8 vs 4.5 consults/1,000 patient-days, P < .00001). The monthly consult rate in the private setting remained steady throughout the year, while the academic rate rose and then fell in accordance with the academic calendar, until statistically equaling the private rate in the final month of the academic year. Urgent consults were more likely to be ordered in the academic setting (7.1% vs 3.1%, P < .001), along with consults for urolithiasis (18.1% vs 12.6%, P < .001). Retention consults were more common in the private setting (23.7% vs 18.3%, P < .001).Conclusions:In this novel analysis, we demonstrated that significant differences exist between inpatient urological consult use in private and academic medical centers. Consults are ordered more frequently in academic hospitals until the end of the academic year, suggesting a learning curve for academic hospital medicine services. Recognition of these practice patterns identifies a potential opportunity to decrease the number of consultations through improved physician education.

Parasitic helminths infect more than 1.5 billion people, with third world countries being the most affected. Parasites are transmitted through soil and contaminated water and they feed on host tissue in order to grow and reproduce. Infections cause anemia, malabsorption of nutrients, and loss of appetite. While inside a host, parasites anaerobically respire by using an alternative electron transport chain that uses rhodoquinone (RQ) as an electron carrier instead of ubiquinone (Q), which is used in aerobic respiration. Mammalian hosts produce and use Q for aerobic respiration, but they do not make or require RQ. An ideal anti‐parasitic drug target would be an enzyme that is used only for the biosynthesis of RQ ‐ not the biosynthesis of Q. Caenorhabditis elegans have been used as a model system for parasitic helminths in order to investigate RQ biosynthesis. RNAi feeding experiments were performed to identify genes required for several steps in the RQ biosynthetic pathway in C. elegans. Several genes were identified that are common to both Q and RQ biosynthetic pathways (coq‐3, coq‐5, and coq‐6). However, knockdown of the kynu‐1 gene from the kynurenine pathway affected only RQ production. Additional experiments involving knock‐outs of other C. elegans genes in the kynurenine pathway confirmed the requirement of kynu‐1 and the corresponding arylamine products for the biosynthesis of RQ. The roles ofcoq‐2 and coq‐3 MV genes in the biosynthesis of RQ in C. elegans were further investigated in this study using RNAi knockdowns and characterization was performed with RT‐qPCR and LC‐MS. Support or Funding Information Gonzaga Science Research Program and Agencia Nacional para la Innovación y la Investigación ANII FCE_1_2014_104366

A key metabolic adaptation for some species that face hypoxia as part of their life-cycle involves an alternative electron transport chain in which rhodoquinone (RQ) is required for fumarate reduction and ATP production. RQ biosynthesis in bacteria and protists requires ubiquinone (Q) as a precursor. In contrast, Q is not a precursor for RQ biosynthesis in animals such as parasitic helminths, and this pathway has remained elusive. We used Caenorhabditis elegans as a model animal to elucidate several key steps in RQ biosynthesis. Through RNA interference and a series of mutants, we found that arylamine metabolites from the kynurenine pathway are essential precursors for RQ biosynthesis de novo. Deletion of kynu-1, which encodes a kynureninase that converts L-kynurenine (KYN) into anthranilic acid (AA), and 3-hydroxykynurenine (HKYN) into 3-hydroxyanthranilic acid (3HAA), completely abolishes RQ biosynthesis, but does not affect Q levels. Deletion of kmo-1, which encodes a kynurenine 3-monooxygenase that converts KYN to HKYN, drastically reduces RQ, but not Q levels. Knockdown of the Q biosynthetic genes, coq-5 and coq-6, affects both Q and RQ levels demonstrating that common enzymes are used in both biosynthetic pathways. Our study reveals that two pathways for RQ biosynthesis have independently