Cytochrome P450 monooxygenases typically catalyze the insertion of one atom of oxygen from O2 into unactivated carbon-hydrogen and carbon-carbon bonds, with concomitant reduction of the other oxygen atom to H2O by NAD(P)H. Comparison of the average structures of the camphor hydroxylase cytochrome P450cam (CYP101) obtained from residual dipolar coupling (RDC)-restrained molecular dynamics (MD) in the presence and absence of substrate camphor shows structural displacements resulting from the essential collapse of the active site upon substrate removal. This collapse has conformational consequences that extend across the protein structure, none of which were observed in analogous crystallographic structures. Mutations were made to test the involvement of the observed conformational changes in substrate binding and recognition. All of the mutations performed based upon the NMR-detected perturbations, even those remote from the active site, resulted in modified substrate selectivity, enzyme efficiency and/or haem iron spin state. The results demonstrate that solution NMR can provide insights into enzyme structure-function relationships that are difficult to obtain by other methods.

The receptor for advanced glycation end products (RAGE) is a multiligand pattern recognition receptor implicated in multiple disease states. Although RAGE is expressed on systemic vascular endothelium, the expression and function of RAGE on lung endothelium has not been studied. Utilizing in vitro (human) and in vivo (mouse) models, we established the presence of RAGE on lung endothelium. Because RAGE ligands can induce the expression of RAGE and stored red blood cells express the RAGE ligand N ε -carboxymethyl lysine, we investigated whether red blood cell (RBC) transfusion would augment RAGE expression on endothelium utilizing a syngeneic model of RBC transfusion. RBC transfusion not only increased lung endothelial RAGE expression but enhanced lung inflammation and endothelial activation, since lung high mobility group box 1 and vascular cell adhesion molecule 1 expression was elevated following transfusion. These effects were mediated by RAGE, since endothelial activation was absent in RBCtransfused RAGE knockout mice. Thus, RAGE is inducibly expressed on lung endothelium, and one functional consequence of RBC transfusion is increased RAGE expression and endothelial activation. receptor for advanced glycation end products; red blood cell transfusion; endothelial cell; lung inflammation; red blood cells THE RECEPTOR FOR ADVANCED glycation end products (RAGE) is widely expressed on systemic endothelium and functions as a pattern recognition receptor for multiple ligands, including advanced glycation end products (AGEs), high mobility group box 1 (HMGB1), calgranulins (s100A12 and s100B), amyloid ␤-proteins, Mac-1, phosphotidylserine, and lipopolysaccharide (10,24,26,35). AGEs, a heterogenous group of adducts formed during pathological states, hyperglycemia, and periods of increased oxidative stress, lead to increased generation of reactive oxygen species (ROS) and inflammatory cytokines following ligation of RAGE expressed on vascular endothelium (25,31,32). We have previously shown that stored red blood cells (RBCs) that express the RAGE ligand N ε -carboxymethyl lysine (N ε -CML) trigger lung endothelial ROS generation that was attenuated by soluble receptor for advanced glycation end products (sRAGE), the extracellular ligandbinding domain of the receptor that acts as a decoy by binding RAGE ligands (19). This finding supports the hypothesis that RAGE ligands on the surface of stored RBCs promote activation of lung endothelium, thus contributing to the pathogenesis of lung injury in susceptible transfusion recipients.Because RAGE is abundantly expressed on alveolar epithelium, particularly type I epithelial cells, and is utilized as a specific marker of alveolar epithelial injury, the existence of RAGE on pulmonary endothelium has come into question (9,28,30). Indeed, prior studies failed to detect RAGE in lung endothelium (9, 28). However, the complexities of RAGE biology render it a difficult molecule to study, since RAGE is known to exist in several different isoforms, subject to cleavage by proteases, ra...

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Clinical guidelines recommend addressing adolescent alcohol use in primary care; the 5 As (Ask, Advise, Assess, Assist, Arrange) may be a useful model for intervention. We audio-recorded 540 visits with 49 physicians and adolescents, compared alcohol disclosure rates in the encounter with those in a survey, and analyzed conversations for use of the 5 As and their relation to adolescent reports of drinking 3 months after the encounter. When physicians asked clear, nonleading questions, drinkers were more likely to disclose alcohol use ( P = .004). In 64% of visits in which alcohol was discussed, physicians used one or more of the 5 As, most frequently "Ask." No physician used all 5 As. Among drinkers, there was no association between physicians' partial use of the 5 As and adolescent alcohol consumption at 3 months. Physicians can learn more effective ways to "Ask" about alcohol use to increase disclosure of drinking and to be more comprehensive in their counseling.

SCI-47 Red cell transfusions are associated with the development of acute lung injury in critically ill patients, yet the mechanisms for this association remain unknown. We have previously shown that stored red blood cells (RBCs) express the advanced glycation end-product Nε-carboxymethyl lysine (Nε-CML) (1). Advanced glycation end-products (AGEs), a heterogeneous group of adducts formed during states of increased oxidative stress or hyperglycemia, are thought to exert their effects by binding to membrane receptors, including RAGE (the receptor for advanced glycation-end products). RAGE is a multiligand pattern-recognition receptor implicated in vascular disease whose function in lung endothelium remains unknown. Our previous data demonstrate that RAGE ligands on stored erythrocytes can induce reactive oxygen species in lung endothelial cells. We therefore hypothesized that RAGE ligands on the surface of stored RBCs exacerbate lung inflammation by interacting with the pulmonary endothelium, thus possibly participating in the pathogenesis of lung injury following transfusion. We first examined lung endothelial cells at baseline using multiple techniques and observed low basal expression of RAGE. Because RAGE ligands can induce the expression of RAGE, and stored red blood cells (RBCs) express the RAGE ligand Nε-carboxymethyl lysine (Nε-CML), we investigated whether RBC transfusion would augment RAGE expression on lung endothelium utilizing a syngeneic model of RBC transfusion. Increased lung endothelial RAGE expression and enhanced lung inflammation and endothelial activation was observed, as evidenced by increases in lung high mobility group box 1 (HMGB1) and vascular cell adhesion molecule (VCAM-1) expression following transfusion. These effects were mediated by RAGE, as endothelial activation was absent in RBC-transfused Rage knockout mice. Therefore, functional consequences of RBC transfusion are augmented RAGE expression, increased RAGE ligation, and endothelial activation, thus linking RAGE activation to lung inflammation following RBC transfusion. Disclosures: No relevant conflicts of interest to declare.

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This case report presents a patient who, while undergoing oral isotretinoin therapy for acne vulgaris, developed onychocryptosis and asymptomatic external urethritis. These uncommon adverse events are not well-documented in medical literature. While his urethritis spontaneously resolved, his onychocryptosis symptoms necessitated surgical intervention. This report illustrates both cosmetic and functional adverse effects of isotretinoin and provides insight into the progression of these reactions over time.