Acute Kidney Injury: Iterative Development of an Audit Tool for Trauma Patients.

BACKGROUND: Acute kidney injury is a low-volume, high-risk complication in trauma patients and is associated with prolonged hospital length of stay and increased mortality. Yet, no audit tools exist to evaluate acute kidney injury in trauma patients. OBJECTIVE: This study aimed to describe the iterative development of an audit tool to evaluate acute kidney injury following trauma. METHODS: Our performance improvement nurses developed an audit tool to evaluate acute kidney injury in trauma patients using an iterative, multiphase process conducted from 2017 to 2021, which included a review of our Trauma Quality Improvement Program data, trauma registry data, literature review, multidisciplinary consensus approach, retrospective and concurrent review, and continuous audit and feedback for piloted and finalized versions of the tool. RESULTS: The final acute kidney injury audit tool can be completed within 30 min using data obtained from the electronic medical record and consists of six sections, including identification criteria, source potential causes, source treatment, acute kidney injury treatment, dialysis indications, and outcome status. CONCLUSION: The iterative development and testing of an acute kidney injury audit tool improved the uniform data collection, documentation, audit, and feedback of best practices to positively impact patient outcomes.

Trajectory of Serum Bilirubin Predicts Spontaneous Recovery in a Real-World Cohort of Patients With Alcoholic Hepatitis.

BACKGROUND AND AIMS: Alcoholic hepatitis (AH) is a severe condition with poor short-term prognosis. Specific treatment with corticosteroids slightly improves short-term survival but is associated with infection and is not used in many centers. A reliable method to identify patients who will recover spontaneously will minimise the numbers of patients who experience side effects of available treatments. METHODS: We analysed the trajectory of serum bilirubin concentration over the course of hospital admissions in patients with AH to predict spontaneous survival and the need for treatment. RESULTS: data from 426 patients were analysed. Based on bilirubin trajectory, patients were categorized into three groups: 'fast fallers' (bilirubin <0.8 x admission value at day 7), 'static' (bilirubin of >0.9 - <1.2 x admission value) and 'rapid risers' (bilirubin of ≥1.2 x admission bilirubin). Fast fallers had significantly better 90-day survival compared to other groups (log rank p < .001), and showed no benefit of corticosteroid therapy (OR for survival at 28 days of treatment, 0.94, 95% CI 0.06 - 8.41). These findings remained even amongst patients with severe disease based on initial DF, GAHS or MELD scores. CONCLUSIONS: We present an intuitive method of classifying patients with AH based on the trajectory of bilirubin over the first week of admission. It is complimentary to existing scores that identify candidates for corticosteroid treatment or assess response to treatment. This method identifies a group of patients with AH who recover spontaneously and can avoid corticosteroid therapy.

Overview of the Neuroprotective Effects of the MAO-Inhibiting Antidepressant Phenelzine.

Phenelzine (PLZ) is a monoamine oxidase (MAO)-inhibiting antidepressant with anxiolytic properties. This multifaceted drug has a number of pharmacological and neurochemical effects in addition to inhibition of MAO, and findings on these effects have contributed to a body of evidence indicating that PLZ also has neuroprotective/neurorescue properties. These attributes are reviewed in this paper and include catabolism to the active metabolite ß-phenylethylidenehydrazine (PEH) and effects of PLZ and PEH on the GABA-glutamate balance in brain, sequestration of reactive aldehydes, and inhibition of primary amine oxidase. Also discussed are the encouraging findings of the effects of PLZ in animal models of stroke, spinal cord injury, traumatic brain injury, and multiple sclerosis, as well other actions such as reduction of nitrative stress, reduction of the effects of a toxin on dopaminergic neurons, potential anticonvulsant actions, and effects on brain-derived neurotrophic factor, neural cell adhesion molecules, an anti-apoptotic factor, and brain levels of ornithine and N-acetylamino acids.

The prescriber's guide to classic MAO inhibitors (phenelzine, tranylcypromine, isocarboxazid) for treatment-resistant depression.

This article is a clinical guide which discusses the "state-of-the-art" usage of the classic monoamine oxidase inhibitor (MAOI) antidepressants (phenelzine, tranylcypromine, and isocarboxazid) in modern psychiatric practice. The guide is for all clinicians, including those who may not be experienced MAOI prescribers. It discusses indications, drug-drug interactions, side-effect management, and the safety of various augmentation strategies. There is a clear and broad consensus (more than 70 international expert endorsers), based on 6 decades of experience, for the recommendations herein exposited. They are based on empirical evidence and expert opinion-this guide is presented as a new specialist-consensus standard. The guide provides practical clinical advice, and is the basis for the rational use of these drugs, particularly because it improves and updates knowledge, and corrects the various misconceptions that have hitherto been prominent in the literature, partly due to insufficient knowledge of pharmacology. The guide suggests that MAOIs should always be considered in cases of treatment-resistant depression (including those melancholic in nature), and prior to electroconvulsive therapy-while taking into account of patient preference. In selected cases, they may be considered earlier in the treatment algorithm than has previously been customary, and should not be regarded as drugs of last resort; they may prove decisively effective when many other treatments have failed. The guide clarifies key points on the concomitant use of incorrectly proscribed drugs such as methylphenidate and some tricyclic antidepressants. It also illustrates the straightforward "bridging" methods that may be used to transition simply and safely from other antidepressants to MAOIs.

Human platelet lysate delivered via an ocular wound chamber for the treatment of corneal epithelial injuries.

Current strategies to address corneal surface defects are insufficient to successfully resolve damage caused by injury and/or disease. To address this issue, we have developed an ocular wound chamber (OWC) that creates a fluid-filled environment by encompassing damaged ocular and periocular tissues allowing for the continuous delivery of therapeutics. This study tested human platelet lysate (hPL) as a treatment for corneal epithelial defects when used with the OWC. Corneal epithelial injuries were created in anesthetized guinea pigs by debridement of the central cornea. An OWC was placed over the injured eye and animals randomly grouped followed by injection of either 20% hPL, 100% hPL, or vehicle (balanced salt solution, BSS) into the chamber. Eyes were assessed at 0, 24, 48, and 72 h using intraocular pressure (IOP), optical coherence tomography (OCT), and fluorescein imaging. Whole globes were histologically processed, and hematoxylin and eosin (H&E) stained. No differences in IOP were recorded as a result of corneal wounding, chamber placement, and/or therapeutic application. OCT images demonstrated increased corneal swelling at 48 h and 72 h in the vehicle group compared to 20% hPL. Fluorescein staining showed increased corneal re-epithelialization in the 20% and 100% hPL groups at 48 h compared to vehicle only. H&E staining revealed increased stromal cellular infiltrate in the BSS group. This study demonstrates the delivery of hPL via the OWC improves corneal re-epithelialization and supports the expanded usage of the chamber in combination with hPL to manage a variety of corneal surface injuries, diseases and/or periocular conditions.

Coagulation abnormalities, bleeding, thrombosis, and management of patients with acute liver failure in Australia and New Zealand.

BACKGROUND AND AIM: To study the management of coagulation and hematological derangements among severe acute liver failure (ALF) patients in Australia and New Zealand liver transplant intensive care units (ICUs). METHODS: Analysis of key baseline characteristics, etiology, coagulation and hematological tests, use of blood products, thrombotic complications, and clinical outcomes during the first ICU week. RESULTS: We studied 62 ALF patients. The first day median peak international normalized ratio was 5.5 (inter-quartile range [IQR] 3.8-8.7), median longest activated partial thromboplastin time was 62 s (IQR 44-87), and median lowest fibrinogen was 1.1 (IQR 0.8-1.6) g/L. Fibrinogen was only measured in 85% of patients, which was less than other tests (P < 0.0001). Median initial lowest platelet count was 83 (IQR 41-122) × 109 /L. Overall, 58% of patients received fresh frozen plasma, 40% cryoprecipitate, 35% platelets, and 15% prothrombin complex concentrate. Patients with bleeding complications (19%) had more severe overall hypofibrinogenemia and thrombocytopenia. Thrombotic complications were less common (10% of patients), were not associated with consistent patterns of abnormal hemostasis, and were not immediately preceded by clotting factor administration and half occurred only after liver transplantation surgery. CONCLUSION: In ALF patients admitted to dedicated Australia and New Zealand ICUs, fibrinogen was measured less frequently than other coagulation parameters but, together with platelets, appeared more relevant to bleeding risk. Blood products and procoagulant factors were administered to most patients at variable levels of hemostatic derangement, and bleeding complications were more common than thrombotic complications. This epidemiologic information and practice variability provide baseline data for the design and powering of interventional studies.

Home-Based Exercise in Patients Awaiting Liver Transplantation: A Feasibility Study.

Frailty is associated with increased mortality both before and after liver transplantation (LT). There are no standardized exercise programs, in particular home-based exercise programs (HBEPs), for patients awaiting LT. The aim was to investigate the feasibility of such a program in patients awaiting LT. Patients were randomly selected from the Birmingham LT waiting list and provided with a 12-week HBEP, including average daily step (ADS) targets and twice-weekly resistance exercises. Feasibility was based on patient eligibility (≥66% of waiting list), target recruitment (≥90% of n = 20), safety (no related serious adverse events), and adherence (≥66% adherence to 6-week HBEP). Measures of aerobic (incremental shuttle walk test [ISWT], ADS), functional capacity (short physical performance battery test [SPPBT]), and health-related quality of life (EuroQol 5-Dimension 5-Level (EQ-5D-5L) and hospital anxiety and depression score [HADS]) were taken at baseline and at 6 and 12 weeks. 18 patients (50% male; median age, 55 years) were recruited. All domains of the study feasibility criteria were met. ISWT improved after 6 weeks (50 m; P ≤ 0.01) and 12 weeks (210 m; P ≤ 0.01), despite withdrawal of the telephone health calls. Similarly, improvements were seen in ADS (2700/day; P ≤ 0.01) and the SPPBT (2.5; P = 0.02) after 12 weeks. There was no difference in HADS (median difference [MD] -3; P = 0.69), but EQ-5D-5L after 12 weeks (17.5%; P = 0.04). In conclusion, a 12-week HBEP, incorporating both easy-to-apply resistance and aerobic exercises, is safe and feasible in patients awaiting LT. Measures of aerobic and functional capacity demonstrate trends toward improvement that warrant further investigation in a randomized controlled trial.

On the practical aspects of characterising monoamine oxidase inhibition in vitro.

The development of novel inhibitors of human monoamine oxidase enzymes with improved pharmacodynamic and pharmacokinetic profiles has, in the past, been hampered by limited access to enzyme, by assay protocols offering limited throughput, and by inappropriate analyses of kinetic data. More recently, high-level expression of human enzymes in yeast has facilitated thorough examinations of steady-state enzyme behaviour that have led to improvements in our understanding of the mathematical underpinnings of kinetic analyses of monoamine oxidases. However, with these improvements have come a realisation that to be useful, more data points across wider concentration ranges are required. In turn, many discontinuous assay approaches, such as those involving radiolabelled substrates or chromatographic separation of product from substrate, have been rendered somewhat obsolete. Justification for the use of a platereader-based approach to assess the effects of novel inhibitors on monamine oxidases is provided, along with details of experimental design optimised to address the unexpectedly complex kinetics followed by these enzymes. Potential sources of error are discussed, and comments provided on techniques that may enhance the quality of experimental data.

Use of an ocular wound chamber for the prevention of exposure keratopathy in a guinea pig model.

Current therapies available to treat and heal ocular surface injuries and periocular burns are frequently inadequate, costly, and labor intensive. To address these limitations, we have employed a flexible, semitransparent ocular wound chamber (OWC) to provide protection as well as a watertight seal to allow for the constant delivery of therapeutics to the ocular surface and surrounding periocular tissue. This study demonstrates the safety and utilization of the OWC on uninjured eyes and in our exposure keratopathy model. For initial safety studies (N = 3 per group), the eyelids remained intact and the eye uninjured. A blepharotomy (N = 6 per group) was performed to remove the upper and lower eyelids surrounding the left (OS) eye to create our exposure keratopathy model. Right (OD) eyes served as uninjured controls in all studies. Following OWC placement, 0.5 mL HPMC gel or balanced saline solution (BSS) was injected into the chamber. Animals were monitored daily and fully assessed via white light, fluorescein, and OCT imaging at least through 72 hours post OWC placement. In studies that included a blepharotomy, skin samples were analyzed by multiplex cytokine analysis. Results of safety experiments revealed no significant differences between treatment groups in corneal thickness, fluorescein staining, OCT imaging, or histological eye or skin sections when compared to control eyes. In our exposure keratopathy model, OWC treated eyes showed significantly less fluorescein uptake and also were found to have significantly lower levels of cytokines IL-13 and IL-5 in skin samples. These results demonstrate for the first time that treatment using the OWC device is not only safe, but significantly protects against blepharotomy-induced exposure keratopathy. As a whole, this study advances our overall efforts to develop a feasible solution to treat ocular surface injuries, infections, and periocular burns.

Transplanting Patients with Alcohol-related Liver Disease in the National Health System: New Rules and Decisions.

AIMS: The UK has a socialized healthcare system that provides treatment that is free at the point of care for acute and chronic health disorders (the National Health Service-NHS), which is currently experiencing a period of unprecedented challenge. METHODS: A narrative review that discusses present and future arrangements for transplantation of alcohol-related liver disease (ArLD) in the UK. RESULTS: Liver disease in the UK is reaching epidemic proportions due to obesity and metabolic disease compounding alcohol-mediated liver damage. Unfortunately, hepatology services in the UK are geographically disparate and subject to significant variations in liver morbidity and mortality, prompting concerns that this may negatively impair access to transplantation. In an attempt to improve referrals to tertiary liver services, the UK listing criteria for alcohol-associated liver disease were revised in 2016 by a working party under the aegis of the UK-Liver Advisory Group with the ambition of increasing opportunities for disease evaluation and improving the condition of candidates referred for assessment. CONCLUSION: Liver transplantation for ArLD is well established in the UK. Recent organizational changes seek to reduce inequities in access to transplant services. SHORT SUMMARY: Liver disease in the UK is reaching epidemic proportions. Concerns over equity of access to liver transplantation prompted revision of the UK listing criteria for alcohol-associated liver disease in 2016, to improve to the availability of tertiary hepatology services. Transplanting patients with alcohol-related liver disease in the National Health System: New Rules and Decisions '…The second property of your excellent sherris is, the warming of the blood; which, before cold and settled, hath left the liver white and pale…'Falstaff; Henry IV Part 2: Act 4, Scene 3.

Tobacco use predicts a more difficult episode of care after anatomic total shoulder arthroplasty.

BACKGROUND: In the current health care environment, it is becoming increasingly important to recognize risks factors that may affect a patient's postoperative outcome. To determine the potential impact of tobacco as a risk factor, we evaluated postoperative pain, narcotic use, length of stay, reoperations, and complications in the global 90-day episode of care for patients undergoing anatomic total shoulder arthroplasty (TSA) who were current tobacco users, former users, or nonusers. METHODS: Database search identified 163 patients with primary anatomic TSA done for glenohumeral arthritis; these were divided into 3 groups: current tobacco users (28), nonusers (88), and former users (47). All surgeries were done with the same technique and implants. RESULTS: Patients in the current tobacco use group had significantly higher visual analog scale scores preoperatively and at 12 weeks postoperatively than nonusers and former users. Mean improvement in visual analog scale scores was significantly less in current tobacco users. Cumulative oral morphine equivalent use at 12 weeks was significantly higher in current tobacco users than in nonusers and former users. The average oral morphine equivalent per day was also significantly higher in the current tobacco users than in nonusers and former users. There were no significant differences in length of stay or complications. CONCLUSIONS: Although length of stay, complication rates, hospital readmissions, and reoperation rates were not significantly different, tobacco users reported increased postoperative pain and narcotic use in the global period after TSA. Former tobacco users were found to have a postoperative course similar to that of nonusers, suggesting that discontinuation of tobacco use can improve a patient's episode of care performance after TSA.

Making the cut: Innovative methods for optimizing perfusion-based migration assays.

Application of fluid shear stress to adherent cells dramatically influences their cytoskeletal makeup and differentially regulates their migratory phenotype. Because cytoskeletal rearrangements are necessary for cell motility and migration, preserving these adaptations under in vitro conditions and in the presence of fluid flow are physiologically essential. With this in mind, parallel plate flow chambers and microchannels are often used to conduct in vitro perfusion experiments. However, both of these systems currently lack capacity to accurately study cell migration in the same location where cells were perfused. The most common perfusion/migration assays involve cell perfusion followed by trypsinization which can compromise adaptive cytoskeletal geometry and lead to misleading phenotypic conclusions. The purpose of this study was to quantitatively highlight some limitations commonly found with currently used cell migration approaches and to introduce two new advances which use additive manufacturing (3D printing) or laser capture microdissection (LCM) technology. The residue-free 3D printed insert allows accurate cell seeding within defined areas, increases cell yield for downstream analyses, and more closely resembles the reported levels of fluid shear stress calculated with computational fluid dynamics as compared to other residue-free cell seeding techniques. The LCM approach uses an ultraviolet laser for "touchless technology" to rapidly and accurately introduce a custom-sized wound area in otherwise inaccessible perfusion microchannels. The wound area introduced by LCM elicits comparable migration characteristics compared to traditional pipette tip-induced injuries. When used in perfusion experiments, both of these newly characterized tools were effective in yielding similar results yet without the limitations of the traditional modalities. These innovative methods provide valuable tools for exploring mechanisms of clinically important aspects of cell migration fundamental to the pathogenesis of many flow-mediated disorders and are applicable to other perfusion-based models where migration is of central importance. © 2016 International Society for Advancement of Cytometry.

ADAM, a hands-on patient simulator for teaching principles of drug disposition and compartmental pharmacokinetics.

AIMS: To design, construct and validate a pharmacokinetics simulator that offers students hands-on opportunities to participate in the design, administration and analysis of oral and intravenous dosing regimens. METHODS: The Alberta Drug Administration Modeller (ADAM) is a mechanical patient in which peristaltic circulation of water through a network of silicone tubing and glass bottles creates a representation of the outcomes of drug absorption, distribution, metabolism and elimination. Changing peristaltic pump rates and volumes in bottles allows values for pharmacokinetic constants to be varied, thereby simulating differences in drug properties and in patient physiologies and pathologies. Following administration of methylene blue dye by oral or intravenous routes, plasma and/or urine samples are collected and drug concentrations are determined spectrophotometrically. The effectiveness of the simulator in enhancing student competence and confidence was assessed in two undergraduate laboratory classes. RESULTS: The simulator effectively models one- and two-compartment drug behaviour in a mathematically-robust and realistic manner. Data allow calculation of numerous pharmacokinetic constants, by traditional graphing methods or with curve-fitting software. Students' competence in solving pharmacokinetic problems involving calculations and graphing improved significantly, while an increase in confidence and understanding was reported. CONCLUSIONS: The ADAM is relatively inexpensive and straightforward to construct, and offers a realistic, hands-on pharmacokinetics learning opportunity for students that effectively complements didactic lectures.

Portopulmonary hypertension: Still an appropriate consideration for liver transplantation?

Liver transplantation (LT) in patients with portopulmonary hypertension (PoPH) has historically resulted in unpredictable and often poor outcomes. The United Kingdom experience for the period 1992-2012 is reported in this article. A retrospective analysis of patients, preoperatively fulfilling the PoPH European Respiratory Society Task Force on Pulmonary-Hepatic Vascular Disorders diagnostic criteria was conducted across all UK LT centers. Data collection included comorbidities, use of preoperative and postoperative pharmacotherapy, patient survival, and cause of death. To enable survival stratification, PoPH was classified as mild, moderate, or severe based on mean pulmonary pressure of <35 mm Hg, 35-49 mm Hg, and ≥50 mm Hg, respectively. Of 127 patients reported to have PoPH, just 28 fulfilled the diagnostic criteria (14 mild, 9 moderate, 5 severe). Twenty (71.4%) patients were male with median age and Model for End-Stage Liver Disease of 50 years (range, 23-62 years) and 18 (range, 6-43), respectively. Twelve (42.9%) patients died within 5 years of LT. The majority of deaths (10 of 12; 83%) occurred within the first 6 months after LT, aetiologies of which included right heart failure (n = 3), progressive PoPH (n = 2), and sepsis (n = 2). Of those receiving preoperative pharmacotherapy (n = 8), 5 are currently alive and were classified as mild to moderate PoPH. Both severe PoPH patients optimized preoperatively with pharmacotherapy died within a year of LT. Development of effective vasodilatory therapies in the setting of pulmonary arterial hypertension has led to a dramatic improvement in patient survival. The available data indicate that in this era of pharmacotherapy, PoPH in isolation no longer represents a valid consideration to transplant. Liver Transplantation 22 1637-1642 2016 AASLD.

AMP-activated protein kinase inhibits transforming growth factor-ß-mediated vascular smooth muscle cell growth: implications for a Smad-3-dependent mechanism.

Dysfunctional vascular growth is a major contributor to cardiovascular disease, the leading cause of morbidity and mortality worldwide. Growth factor-induced activation of vascular smooth muscle cells (VSMCs) results in a phenotypic switch from a quiescent, contractile state to a proliferative state foundational to vessel pathology. Transforming growth factor-ß (TGF-ß) is a multifunctional signaling protein capable of growth stimulation via Smad signaling. Although Smad signaling is well characterized in many tissues, its role in VSM growth disorders remains controversial. Recent data from our lab and others implicate the metabolic regulator AMP-activated protein kinase (AMPK) in VSM growth inhibition. We hypothesized that AMPK inhibits VSMC proliferation by reducing TGF-ß-mediated growth in a Smad-dependent fashion. Treatment of rat VSMCs with the AMPK agonist AICAR significantly decreased TGF-ß-mediated activation of synthetic Smad2 and Smad3 and increased inhibitory Smad7. Flow cytometry and automated cell counting revealed that AICAR reversed TGF-ß-mediated cell cycle progression at 24 h and elevated cell numbers at 48 h. TGF-ß/Smad signaling increased the G0/G1 inducers cyclin D1/cyclin-dependent kinase (CDK) 4 and cyclin E/CDK2; however, AICAR reversed these events while increasing cytostatic p21. The specific role of Smad3 in AMPK-mediated reversal of TGF-ß-induced growth was then explored using adenovirus-mediated Smad3 overexpression (Ad-Smad3). Ad-Smad3 cells increased cell cycle progression and cell numbers compared with Ad-GFP control cells, and these were restored to basal levels with concomitant AICAR treatment. These findings support a novel AMPK target in TGF-ß/Smad3 for VSMC growth control and support continued investigation of AMPK as a possible therapeutic target for reducing vascular growth disorders.

Therapeutic plasma exchange does not reduce vasopressor requirement in severe acute liver failure: a retrospective case series.

BACKGROUND: In acute liver failure (ALF) therapeutic plasma exchange (TPE) improves laboratory measures of liver function. In patients with ALF requiring minimal vasoactive support TPE has also been shown to provide haemodynamic benefits including an increase in systemic blood pressure. However the haemodynamic effects of TPE in patients with severe ALF requiring moderate or high dose vasopressor therapy has not been reported. We retrospectively examined the haemodynamic effects of TPE in a cohort of patients with severe ALF requiring vasopressor therapy. METHODS: Physiological, laboratory and treatment data were collected on all patients with ALF who received TPE between January 2000 and December 2012. All patients were managed in the intensive care unit of a tertiary referral centre for ALF and liver transplantation. The primary outcome measures were changes in mean arterial pressure (MAP), vasopressor score and the ratio of vasopressor score to MAP (vasopressor dependency index (VDI)) from baseline prior to TPE through to 12 hours after completion of TPE. Secondary outcome measures were changes in other routinely collected physiological variables and laboratory results. Results are presented as median (interquartile range (IQR)). Outcome measures were evaluated using a mixed effect model. RESULTS: Thirty nine TPE were performed in 17 patients with ALF (13 paracetamol poisoning). All TPE were performed with a centrifugal apheresis system (duration 130 minutes (IQR 115 - 147.5), plasma volume removed 5.1% body weight (IQR 4.6 - 5.5). Baseline values for primary outcome measures were: MAP 82 mmHg (IQR 72 - 92.5), vasopressor score 8.35 (IQR 3.62 - 24.6) and VDI 0.10 (IQR 0.05 - 0.31). MAP was significantly higher immediately after TPE compared to baseline (p = 0.039), however when corrected for change in vasopressor requirement there was no significant change in VDI with TPE (p = 0.953). Twelve hours after TPE the MAP, vasopressor score and VDI were not significantly different from baseline (p = 0.563, p = 0.317 and p = 0.214 respectively). CONCLUSION: In this cohort of patients with severe ALF centrifugal TPE did not significantly affect vasopressor requirements.

Modulation of resistance artery tone by the trace amine ß-phenylethylamine: dual indirect sympathomimetic and α1-adrenoceptor blocking actions.

The trace amine ß-phenylethylamine (PEA) is normally present in the body at low nanomolar concentrations but can reach micromolar levels after ingestion of drugs that inhibit monoamine oxidase and primary amine oxidase. In vivo, PEA elicits a robust pressor response, but there is no consensus regarding the underlying mechanism, with both vasodilation and constriction reported in isolated blood vessels. Using functional and biochemical approaches, we found that at low micromolar concentrations PEA (1-30 µM) enhanced nerve-evoked vasoconstriction in the perfused rat mesenteric bed but at a higher concentration (100 µM) significantly inhibited these responses. The α2-adrenoceptor antagonist rauwolscine (1 µM) also enhanced nerve-mediated vasoconstriction, but in the presence of both rauwolscine (1 µM) and PEA (30 µM) together, nerve-evoked responses were initially potentiated and then showed time-dependent rundown. PEA (10 and 100 µM) significantly increased noradrenaline outflow from the mesenteric bed as determined by high-pressure liquid chromatography coupled with electrochemical detection. In isolated endothelium-denuded arterial segments, PEA (1 µM to 1 mM) caused concentration-dependent reversal of tone elicited by the α1-adrenoceptor agonists noradrenaline (EC50 51.69 ± 10.8 µM; n = 5), methoxamine (EC50 68.21 ± 1.70 µM; n = 5), and phenylephrine (EC50 67.74 ± 16.72 µM; n = 5) but was ineffective against tone induced by prostaglandin F2 α or U46619 (9,11-dideoxy-9α,11α-methanoepoxyprostaglandin F2 α). In rat brain homogenates, PEA displaced binding of both [(3)H]prazosin (Ki ≈ 25 µM) and [(3)H]rauwolscine (Ki ≈ 1.2 µM), ligands for α1- and α2-adrenoceptors, respectively. These data provide the first demonstration that dual indirect sympathomimetic and α1-adrenoceptor blocking actions underlie the vascular effects of PEA in resistance arteries.

Common femoral vein reconstruction using internal jugular vein after blast injury.

Common femoral vein traumatic injuries are rare. Surgical management is controversial and by nature case specific. In this report, we present an unusual case of an isolated common femoral vein injury from a gunshot blast repaired with an interposition internal jugular vein bypass. To our knowledge, this is the first reported case of an isolated common femoral vein reconstructed in this manner.

Crystallographic snapshots of the complete reaction cycle of nicotine degradation by an amine oxidase of the monoamine oxidase (MAO) family.

FAD-linked oxidases constitute a class of enzymes which catalyze dehydrogenation as a fundamental biochemical reaction, followed by reoxidation of reduced flavin. Here, we present high-resolution crystal structures showing the flavoenzyme 6-hydroxy-l-nicotine oxidase in action. This enzyme was trapped during catalytic degradation of the native substrate in a sequence of discrete reaction states corresponding to the substrate-reduced enzyme, a complex of the enzyme with the intermediate enamine product and formation of the final aminoketone product. The inactive d-stereoisomer binds in mirror symmetry with respect to the catalytic axis, revealing absolute stereospecificity of hydrogen transfer to the flavin. The structural data suggest deprotonation of the substrate when bound at the active site, an overall binary complex mechanism and oxidation by direct hydride transfer. The amine nitrogen has a critical role in the dehydrogenation step and may activate carbocation formation at the α-carbon via delocalization from the lone pair to σ* C(α)-H. Enzymatically assisted hydrolysis of the intermediate product occurs at a remote (P site) cavity. Substrate entry and product exit follow different paths. Structural and kinetic data suggest that substrate can also bind to the reduced enzyme, associated with slower reoxidation as compared to the rate of reoxidation of free enzyme. The results are of general relevance for the mechanisms of flavin amine oxidases.

BDNF and cAMP are neuroprotective in a porcine model of traumatic optic neuropathy.

Traumatic optic neuropathy (TON) is a devastating condition that can occur after blunt or penetrating trauma to the head, leading to visual impairment or blindness. Despite these debilitating effects, no clinically available therapeutic targets neuroprotection or promotes axon regeneration in this or any optic neuropathy. Limited data in large-animal models are a major obstacle to advancing treatments toward clinical therapeutics. To address this issue, we refined a surgical model of TON in Yucatan minipigs. First, we validated the model by demonstrating visual impairment by flash visual-evoked potential and retinal ganglion cell degeneration and death. Next, we developed and optimized a delivery method and nontoxic dosing of intravitreal brain-derived neurotrophic factor (BDNF) and cAMP. Finally, we showed that intravitreal injection of BDNF and cAMP rescued visual function and protected against retinal ganglion cell death and optic nerve axon degeneration. Together these data in a preclinical large-animal model advance our understanding of and ability to model TON and further identify and develop candidate clinical therapeutics.