A qualitative study of an undergraduate online emergency medicine education program at a teaching Hospital in Kampala, Uganda.

BACKGROUND: Globally, half of all years of life lost is due to emergency medical conditions, with low- and middle-income countries (LMICs) facing a disproportionate burden of these conditions. There is an urgent need to train the future physicians in LMICs in the identification and stabilization of patients with emergency medical conditions. Little research focuses on the development of effective emergency medicine (EM) medical education resources in LMICs and the perspectives of the students themselves. One emerging tool is the use of electronic learning (e-learning) and blended learning courses. We aimed to understand Uganda medical trainees' use of learning materials, perception of current e-learning resources, and perceived needs regarding EM skills acquisition during participation in an app-based EM course. METHODS: We conducted semi-structured interviews and focus groups of medical students and EM residents. Participants were recruited using convenience sampling. All sessions were audio recorded and transcribed verbatim. The final codebook was approved by three separate investigators, transcripts were coded after reaching consensus by all members of the coding team, and coded data were thematically analyzed. RESULTS: Twenty-six medical trainees were included in the study. Analysis of the transcripts revealed three major themes: [1] medical trainees want education in EM and actively seek EM training opportunities; [2] although the e-learning course supplements knowledge acquisition, medical students are most interested in hands-on EM-related training experiences; and [3] medical students want increased time with local physician educators that blended courses provide. CONCLUSIONS: Our findings show that while students lack access to structured EM education, they actively seek EM knowledge and practice experiences through self-identified, unstructured learning opportunities. Students value high quality, easily accessible EM education resources and employ e-learning resources to bridge gaps in their learning opportunities. However, students desire that these resources be complemented by in-person educational sessions and executed in collaboration with local EM experts who are able to contextualize materials, offer mentorship, and help students develop their interest in EM to continue the growth of the EM specialty.

Platensimycin is a selective FabF inhibitor with potent antibiotic properties.

Bacterial infection remains a serious threat to human lives because of emerging resistance to existing antibiotics. Although the scientific community has avidly pursued the discovery of new antibiotics that interact with new targets, these efforts have met with limited success since the early 1960s. Here we report the discovery of platensimycin, a previously unknown class of antibiotics produced by Streptomyces platensis. Platensimycin demonstrates strong, broad-spectrum Gram-positive antibacterial activity by selectively inhibiting cellular lipid biosynthesis. We show that this anti-bacterial effect is exerted through the selective targeting of beta-ketoacyl-(acyl-carrier-protein (ACP)) synthase I/II (FabF/B) in the synthetic pathway of fatty acids. Direct binding assays show that platensimycin interacts specifically with the acyl-enzyme intermediate of the target protein, and X-ray crystallographic studies reveal that a specific conformational change that occurs on acylation must take place before the inhibitor can bind. Treatment with platensimycin eradicates Staphylococcus aureus infection in mice. Because of its unique mode of action, platensimycin shows no cross-resistance to other key antibiotic-resistant strains tested, including methicillin-resistant S. aureus, vancomycin-intermediate S. aureus and vancomycin-resistant enterococci. Platensimycin is the most potent inhibitor reported for the FabF/B condensing enzymes, and is the only inhibitor of these targets that shows broad-spectrum activity, in vivo efficacy and no observed toxicity.

Identification of a potent synthetic FXR agonist with an unexpected mode of binding and activation.

The farnesoid X receptor (FXR), a member of the nuclear hormone receptor family, plays important roles in the regulation of bile acid and cholesterol homeostasis, glucose metabolism, and insulin sensitivity. There is intense interest in understanding the mechanisms of FXR regulation and in developing pharmaceutically suitable synthetic FXR ligands that might be used to treat metabolic syndrome. We report here the identification of a potent FXR agonist (MFA-1) and the elucidation of the structure of this ligand in ternary complex with the human receptor and a coactivator peptide fragment using x-ray crystallography at 1.9-A resolution. The steroid ring system of MFA-1 binds with its D ring-facing helix 12 (AF-2) in a manner reminiscent of hormone binding to classical steroid hormone receptors and the reverse of the pose adopted by naturally occurring bile acids when bound to FXR. This binding mode appears to be driven by the presence of a carboxylate on MFA-1 that is situated to make a salt-bridge interaction with an arginine residue in the FXR-binding pocket that is normally used to neutralize bound bile acids. Receptor activation by MFA-1 differs from that by bile acids in that it relies on direct interactions between the ligand and residues in helices 11 and 12 and only indirectly involves a protonated histidine that is part of the activation trigger. The structure of the FXR:MFA-1 complex differs significantly from that of the complex with a structurally distinct agonist, fexaramine, highlighting the inherent plasticity of the receptor.

Seasonal influence of tuberculosis diagnosis in Rwanda.

BACKGROUND: Tuberculosis (TB) remains a major global health concern. Previous research reveals that TB may have a seasonal peak during the spring and summer seasons in temperate climates; however, few studies have been conducted in tropical climates. This study evaluates the influence of seasonality on laboratory-confirmed TB diagnosis in Rwanda, a tropical country with two rainy and two dry seasons. METHODS: A retrospective chart review was performed at the University Teaching Hospital-Kigali (CHUK). From January 2016 to December 2017, 2717 CHUK patients with TB laboratory data were included. Data abstracted included patient demographics, season, HIV status, and TB laboratory results (microscopy, GeneXpert, culture). Univariate and multivariable logistic regression (adjusted for age, gender, and HIV status) analyses were performed to assess the association between season and laboratory-confirmed TB diagnoses. RESULTS: Patients presenting during rainy season periods had a lower odds of laboratory-confirmed TB diagnosis compared to the dry season (aOR=0.78, 95% CI 0.63-0.97, p=0.026) when controlling for age group, gender, and HIV status. Males, adults, and people living with HIV were more likely to have laboratory-confirmed TB diagnosis. On average, more people were tested for TB during the rainy season per month compared to the dry season (120.3 vs. 103.3), although this difference was not statistically significant. CONCLUSION: In Rwanda, laboratory-confirmed TB case detection shows a seasonal variation with patients having higher odds of TB diagnosis occurring in the dry season. Further research is required to further elucidate this relationship and to delineate the mechanism of season influence on TB diagnosis.

The SuperCam Instrument Suite on the NASA Mars 2020 Rover: Body Unit and Combined System Tests.

The SuperCam instrument suite provides the Mars 2020 rover, Perseverance, with a number of versatile remote-sensing techniques that can be used at long distance as well as within the robotic-arm workspace. These include laser-induced breakdown spectroscopy (LIBS), remote time-resolved Raman and luminescence spectroscopies, and visible and infrared (VISIR; separately referred to as VIS and IR) reflectance spectroscopy. A remote micro-imager (RMI) provides high-resolution color context imaging, and a microphone can be used as a stand-alone tool for environmental studies or to determine physical properties of rocks and soils from shock waves of laser-produced plasmas. SuperCam is built in three parts: The mast unit (MU), consisting of the laser, telescope, RMI, IR spectrometer, and associated electronics, is described in a companion paper. The on-board calibration targets are described in another companion paper. Here we describe SuperCam's body unit (BU) and testing of the integrated instrument. The BU, mounted inside the rover body, receives light from the MU via a 5.8 m optical fiber. The light is split into three wavelength bands by a demultiplexer, and is routed via fiber bundles to three optical spectrometers, two of which (UV and violet; 245-340 and 385-465 nm) are crossed Czerny-Turner reflection spectrometers, nearly identical to their counterparts on ChemCam. The third is a high-efficiency transmission spectrometer containing an optical intensifier capable of gating exposures to 100 ns or longer, with variable delay times relative to the laser pulse. This spectrometer covers 535-853 nm ( 105 - 7070 cm - 1 Raman shift relative to the 532 nm green laser beam) with 12 cm - 1 full-width at half-maximum peak resolution in the Raman fingerprint region. The BU electronics boards interface with the rover and control the instrument, returning data to the rover. Thermal systems maintain a warm temperature during cruise to Mars to avoid contamination on the optics, and cool the detectors during operations on Mars. Results obtained with the integrated instrument demonstrate its capabilities for LIBS, for which a library of 332 standards was developed. Examples of Raman and VISIR spectroscopy are shown, demonstrating clear mineral identification with both techniques. Luminescence spectra demonstrate the utility of having both spectral and temporal dimensions. Finally, RMI and microphone tests on the rover demonstrate the capabilities of these subsystems as well.

The three-dimensional structure of MAP kinase p38beta: different features of the ATP-binding site in p38beta compared with p38alpha.

The p38 mitogen-activated protein kinases are activated in response to environmental stress and cytokines and play a significant role in transcriptional regulation and inflammatory responses. Of the four p38 isoforms known to date, two (p38alpha and p38beta) have been identified as targets for cytokine-suppressive anti-inflammatory drugs. Recently, it was reported that specific inhibition of the p38alpha isoform is necessary and sufficient for anti-inflammatory efficacy in vivo, while further inhibition of p38beta may not provide any additional benefit. In order to aid the development of p38alpha-selective compounds, the three-dimensional structure of p38beta was determined. To do so, the C162S and C119S,C162S mutants of human MAP kinase p38beta were cloned, expressed in Escherichia coli and purified. Initial screening hits in crystallization trials in the presence of an inhibitor led upon optimization to crystals that diffracted to 2.05 A resolution and allowed structure determination (PDB codes 3gc8 and 3gc9 for the single and double mutant, respectively). The structure of the p38alpha C162S mutant in complex with the same inhibitor is also reported (PDB code 3gc7). A comparison between the structures of the two kinases showed that they are highly similar overall but that there are differences in the relative orientation of the N- and C-terminal domains that causes a reduction in the size of the ATP-binding pocket in p38beta. This difference in size between the two pockets could be exploited in order to achieve selectivity.

Isolation, enzyme-bound structure and antibacterial activity of platencin A1 from Streptomyces platensis.

Natural products continue to serve as one of the best sources for discovery of antibacterial agents as exemplified by the recent discoveries of platensimycin and platencin. Chemical modifications as well as discovery of congeners are the main sources for gaining knowledge of structure-activity relationship of natural products. Screening for congeners in the extracts of the fermentation broths of Streptomyces platensis led to the isolation of platencin A(1), a hydroxy congener of platencin. The hydroxylation of the tricyclic enone moiety negatively affected the antibacterial activity and appears to be consistent with the hydrophobic binding pocket of the FabF. Isolation, structure, enzyme-bound structure and activity of platencin A(1) and two other congeners have been described.

Diagnosis of acute HIV infection in Connecticut.

Acute HIV infection (AHI) is the earliest stage of HIV disease, when plasma HIV viremia, but not HIV antibodies, can be detected. Acute HIV infection often presents as a nonspecific viral syndrome. However, its diagnosis, which enables linkage to early medical care and limits further HIV transmission, is seldom made. We describe the experience of Yale's Center for Interdisciplinary Research on AIDS with AHI diagnosis in Connecticut, as a participating center in the National Institute of Mental Health Multisite AHI Study. We sought to identify AHI cases by clinical referrals and by screening for AHI at two substance abuse care facilities and an STD clinic. We identified one case by referral and one through screening of 590 persons. Screening for AHI is feasible and probably cost effective. Primary care providers should include AHI in the differential diagnosis when patients present with a nonspecific viral syndrome.

The differential interactions of peroxisome proliferator-activated receptor gamma ligands with Tyr473 is a physical basis for their unique biological activities.

Despite their proven antidiabetic efficacy, widespread use of peroxisome proliferator-activated receptor (PPAR)gamma agonists has been limited by adverse cardiovascular effects. To overcome this shortcoming, selective PPARgamma modulators (SPPARgammaMs) have been identified that have antidiabetic efficacy comparable with full agonists with improved tolerability in preclinical species. The results of structural studies support the proposition that SPPARgammaMs interact with PPARgamma differently from full agonists, thereby providing a physical basis for their novel activities. Herein, we describe a novel PPARgamma ligand, SPPARgammaM2. This compound was a partial agonist in a cell-based transcriptional activity assay, with diminished adipogenic activity and an attenuated gene signature in cultured human adipocytes. X-ray cocrystallography studies demonstrated that, unlike rosiglitazone, SPPARgammaM2 did not interact with the Tyr473 residue located within helix 12 of the ligand binding domain (LBD). Instead, SPPARgammaM2 was found to bind to and activate human PPARgamma in which the Tyr473 residue had been mutated to alanine (hPPARgammaY473A), with potencies similar to those observed with the wild-type receptor (hPPARgammaWT). In additional studies, we found that the intrinsic binding and functional potencies of structurally distinct SPPARgammaMs were not diminished by the Y473A mutation, whereas those of various thiazolidinedione (TZD) and non-TZD PPARgamma full agonists were reduced in a correlative manner. These results directly demonstrate the important role of Tyr473 in mediating the interaction of full agonists but not SPPARgammaMs with the PPARgamma LBD, thereby providing a precise molecular determinant for their differing pharmacologies.

Anti-arrhythmic and vasopressor medications for the treatment of ventricular fibrillation in severe hypothermia: a systematic review of the literature.

OBJECTIVE: To determine the rate of return of spontaneous circulation (ROSC) in animal models performing resuscitation from induced ventricular fibrillation (VF) in severe hypothermia (<30 degrees C). MATERIALS AND METHODS: A medical literature database search from 1966 to present was performed identifying placebo controlled trials using anti-arrhythmic or vasopressor medications to treat ventricular fibrillation in the setting of severe hypothermia. RESULTS: 7 controlled studies were identified (n=117) testing 6 combinations of resuscitative medications. ROSC rates for treatment versus control groups were as follows: amiodarone (6% vs. 18%, p=0.6, n=34), bretylium (35% vs. 35%, p=1.0, n=40), intermediate- and high-dose epinephrine (adrenaline) (36% vs. 27%, p=1.0, n=22), vasopressin (60% vs. 0%, p<0.0001, n=39), vasopressin and amiodarone (0% vs. 0%, p=NS, n=11), low-dose epinephrine and amiodarone (91% vs. 30%, p=0.0075, n=21). Cumulatively, among all studies administering vasopressors, the rate of ROSC was 62% in treatment groups contrasted to 17% in control groups (p<0.0001, n=77). CONCLUSIONS: In controlled animal models of severe hypothermia, ROSC rates for induced ventricular fibrillation are higher with utilization of vasopressor medications. Current guidelines which recommend withholding these medications in the setting of hypothermic cardiac arrest should be re-evaluated.

International emergency medicine: a review of the literature from 2007.

The subspecialty of international emergency medicine (IEM) continues to grow within the United States, just as the specialty of emergency medicine (EM) continues to spread to both developed and developing countries around the world. One of the greatest obstacles, however, faced by IEM researchers and practitioners alike, remains the lack of a high-quality, consolidated, and easily accessible evidence-base of literature. In response to this perceived need, members of the Emergency Medicine Resident Association (EMRA) International Emergency Medicine Committee, in conjunction with members of the Society for Academic Emergency Medicine (SAEM) International Health Interest Group, have embarked on the task of creating a recurring review of IEM literature. This publication represents the third annual review, covering the top 30 IEM research articles published in 2007. Articles were selected for the review according to explicit, predetermined criteria that included both methodologic quality and perceived impact of the research. It is hoped that this annual review will act as a forum for disseminating best practices, while also stimulating further research in the field of IEM.

HIV/AIDS, conflict and security in Africa: rethinking relationships.

The effect of conflict on HIV transmission and regional and global security has been the subject of much recent discussion and debate. Many long held assumptions regarding these relationships are being reconsidered. Conflict has long been assumed to contribute significantly to the spread of HIV infection. However, new research is casting doubt on this assumption. Studies from Africa suggest that conflict does not necessarily predispose to HIV transmission and indeed, there is evidence to suggest that recovery in the "post-conflict" state is potentially dangerous from the standpoint of HIV transmission. As well, refugee populations have been previously considered as highly infected vectors of HIV transmission. But in light of new investigation this belief is also being reconsidered. There has additionally been concern that high rates of HIV infection among many of the militaries of sub-Saharan Africa poses a threat to regional security. However, data is lacking on both dramatically elevated prevalence amongst soldiers and a possible negative effect on regional security. Nevertheless, HIV/AIDS remain a serious threat to population health and economic well being in this region. These issues are of vital importance for HIV programming and health sector development in conflict and "post-conflict" societies and will constitute formidable challenges to the international community. Further research is required to better inform the discussion of HIV, conflict, and security in sub-Saharan Africa.

A paradoxical peace: HIV in post-conflict states.

Conflict has traditionally been thought to contribute to the epidemic spread of HIV. New data call into question this assumption, and there is concern that the 'post-conflict phase' may be a particularly dangerous time for HIV transmission. The post-conflict phase is characterized by a potentially disastrous confluence of factors including demobilization of combatants, the presence of peacekeeping forces, the return of potentially infected soldiers and refugees, high-risk behaviours and persistent economic and social debilitation. These factors, along with the concentration of populations into cities and urban areas, may further increase the risk to these populations of HIV infection. Further research and study are required to adequately inform and address the issue of HIV transmission in post-conflict societies.

Comparison of Online and Classroom-based Formats for Teaching Emergency Medicine to Medical Students in Uganda.

OBJECTIVES: Severe global shortages in the health care workforce sector have made improving access to essential emergency care challenging. The paucity of trained specialists in low- and middle-income countries translates to large swathes of the population receiving inadequate care. Efforts to expand emergency medicine (EM) education are similarly impeded by a lack of available and appropriate teaching faculty. The development of comprehensive, online medical education courses offers a potentially economical, scalable, and lasting solution for universities experiencing professional shortages. METHODS: An EM course addressing core concepts and patient management was developed for medical students enrolled at Makerere University College of Health Sciences in Kampala, Uganda. Material was presented to students in two comparable formats: online video modules and traditional classroom-based lectures. Following completion of the course, students were assessed for knowledge gains. RESULTS: Forty-two and 48 students enrolled and completed all testing in the online and classroom courses, respectively. Student knowledge gains were equivalent (classroom 25 ± 8.7% vs. online 23 ± 6.5%, p = 0.18), regardless of the method of course delivery. CONCLUSIONS: A summative evaluation of Ugandan medical students demonstrated that online teaching modules are effectively equivalent and offer a viable alternative to traditional classroom-based lectures delivered by on-site, visiting faculty in their efficacy to teach expertise in EM. Web-based curriculum can help alleviate the burden on universities in developing nations struggling with a critical shortage of health care educators while simultaneously satisfying the growing community demand for access to emergency medical care. Future studies assessing the long-term retention of course material could gauge its incorporation into clinical practice.

Expression, purification and crystallization of human 5-lipoxygenase-activating protein with leukotriene-biosynthesis inhibitors.

The nuclear membrane protein 5-lipoxygenase-activating protein (FLAP) plays an essential role in leukotriene synthesis. Recombinant full-length human FLAP with a C-terminal hexahistidine tag has been expressed and purified from the cytoplasmic membrane of Escherichia coli. Diffraction-quality crystals of FLAP in complex with leukotriene-synthesis inhibitor MK-591 and with an iodinated analogue of MK-591 have been grown using the sitting-drop vapor-diffusion method. The crystals exhibit tetragonal symmetry (P42(1)2) and diffracted to a resolution limit of 4 A.

Potential for HIV transmission through unsafe injections.

We tested for HIV in discarded needles and syringe washes from 191 HIV-infected patients receiving injections in rural Cameroon. HIV-1 RNA was amplified from 34 of 103 intravenous injection syringes and two of 88 intramuscular injection syringes. All 36 strains were HIV-1 group M. The majority belonged to the circulating recombinant form CRF02 (IbNg). Our data support a role for unsafe injections in the spread of HIV-1 in Africa, in contrast to recent studies.

Lattice stabilization and enhanced diffraction in human p38 alpha crystals by protein engineering.

Mitogen-activated protein (MAP) kinase p38 alpha is activated in response to environmental stress and cytokines, and plays a significant role in inflammatory responses. For these reasons, it is an important target for the treatment of a wide range of inflammatory and autoimmune diseases. The crystals of p38 alpha that we obtained by published procedures were usually small, quite mosaic, and difficult to reproduce and thus posed a difficulty for the intensive high-resolution studies required for a structure-guided drug discovery approach. Based on crystallographic and biochemical evidences, we prepared a single point mutation of a surface cysteine (C162S) and found that it prevents aggregation and improves the homogeneity and stability of the enzyme. This mutation also facilitates the crystallization process and increases the diffracting power of p38 alpha crystals. Surprisingly, we found that the mutation induces a change in the conformation of a nearby surface loop resulting in stronger lattice interactions, consistent with the improved crystal quality. The mutant protein, because of its improved stability and strengthened lattice interactions, thus provides a significantly improved reagent for use in structure-based drug design for this important disease target.

Design and synthesis of alpha-aryloxyphenylacetic acid derivatives: a novel class of PPARalpha/gamma dual agonists with potent antihyperglycemic and lipid modulating activity.

The synthesis and structure-activity relationships of novel series of alpha-aryloxyphenylacetic acids as PPARalpha/gamma dual agonists are reported. The initial search for surrogates of the ester group in the screen lead led first to the optimization of a subseries with a ketone moiety. Further efforts to modify the ketone subseries led to the design and synthesis of two new subseries containing fused heterocyclic ring systems. All these analogues were characterized by their "super" PPARalpha agonist activity and weak or partial agonist activity on PPARgamma in PPAR-GAL4 transactivation assays despite their similar binding affinities for both receptors. The cocrystal structures of compounds 7 and rosiglitazone with PPARgamma-LBD were compared, and significant differences were found in their interactions with the receptor. Select analogues in each subseries were further evaluated for in vivo efficacy. They all showed excellent anti-hyperglycemic efficacy in a db/db mouse model and hypolipidemic activity in hamster and dog models without provoking the typical PPARgamma-associated side effects in the rat tolerability assay.

The structure of JNK3 in complex with small molecule inhibitors: structural basis for potency and selectivity.

The c-Jun terminal kinases (JNKs) are members of the mitogen-activated protein (MAP) kinase family and regulate signal transduction in response to environmental stress. Activation of JNK3, a neuronal-specific isoform, has been associated with neurological damage, and as such, JNK3 may represent an attractive target for the treatment of neurological disorders. The MAP kinases share between 50% and 80% sequence identity. In order to obtain efficacious and safe compounds, it is necessary to address the issues of potency and selectivity. We report here four crystal structures of JNK3 in complex with three different classes of inhibitors. These structures provide a clear picture of the interactions that each class of compound made with the kinase. Knowledge of the atomic interactions involved in these diverse binding modes provides a platform for structure-guided modification of these compounds, or the de novo design of novel inhibitors that could satisfy the need for potency and selectivity.

Reducing the peptidyl features of caspase-3 inhibitors: a structural analysis.

Caspases are cysteine proteases that specifically cleave Asp-Xxx bonds. They are key agents in inflammation and apoptosis and are attractive targets for therapy against inflammation, neurodegeneration, ischemia, and cancer. Many caspase structures are known, but most involve either peptide or protein inhibitors, unattractive candidates for drug development. We present seven crystal structures of inhibited caspase-3 that illustrate several approaches to reducing the peptidyl characteristics of the inhibitors while maintaining their potency and selectivity. The inhibitors reduce the peptidyl nature of inhibitors while preserving binding potency by (1). exploiting a hydrophobic binding site C-terminal to the cleavage site, (2). replacing the negatively charged aspartyl residue at P4 with neutral groups, and (3). using a peptidomimetic 5,6,7-tricyclic system or a pyrazinone at P2-P3. In addition, we have found that two nicotinic acid aldehydes induce a significant conformational change in the S2 and S3 subsites of caspase-3, revealing an unexpected binding mode. These results advance the search for caspase-directed drugs by revealing how unacceptable molecular features can be removed without loss of potency.