Aortic Delamination—A Possible Precursor of Impending Catastrophe

Aortic diameter is a powerful predictor of adverse aortic events, such as aortic rupture or dissection, forming the basis of prophylactic surgical repair criteria. Limited evidence is available regarding the association of aortic wall thickness (AWT) with these adverse aortic events. We present the case and surgical video of a 73-year-old man with chest pain and an increased AWT, who underwent ascending aortic repair and deep hemiarch placement under deep hypothermic circulatory arrest. Surgical pathology demonstrated evidence of aortic delamination and medial separation, indicative of an impending dissection. The patient recovered uneventfully, and his chest pain ultimately resolved after open repair. In this patient, increased AWT was felt to be the precursor to a potential aortic catastrophe.     

Differential antibody recognition of FC27-like Plasmodium falciparum merozoite surface protein MSP2 antigens which lack 12 amino acid repeats

Three alleles of the FC27-type allelic family of the MSP2 gene of the malaria parasite Plasmodium falciparum have been sequenced from parasites from the field (The Gambia and Tanzania). These alleles lack the 12 amino acid repeat units which are usual in this family of MSP2 alleles. We have investigated the recognition by sera from an endemic area (The Gambia) of three recombinant MSP2 proteins that have 5, 1 and no copies of this repeat region. Antibody recognition of these recombinant proteins varied according to the number of repeats present. High titre antibody levels were seen with most sera using the recombinant protein with 5 × 12-mer repeats, whereas only low responses were measured using proteins containing 1 or no 12-mer repeats. Several sera entirely failed to recognise the protein which lacked 12-mer repeats. The data suggest that variation in the number of tandem repeat sequences could allow the parasite to avoid high avidity antibody binding and this may allow escape from immune recognition.     

Pre-Hospital Diagnosis in Mobile Stroke Unit

ObjectivesMobile stroke unit (MSU) has been shown to rapidly provide pre-hospital thrombolysis in acute ischemic stroke (AIS). MSU encounters neurological disorders other than AIS that require emergent treatment.Methods/MaterialsWe obtained pre-hospital diagnosis and treatment data from the prospectively collected dataset on 221 consecutive MSU encounters. Based on initial clinical evaluation and neuroimaging obtained on MSU, the diagnosis of AIS (definite, probable, and possible AIS, transient ischemic attack), intracranial hemorrhage, and likely stroke mimics was made.ResultsFrom July 2014 to April 2015, 221 patients were treated on MSU. 78 (35%) patients had initial clinical diagnosis of definite/probable AIS or TIA, 69 (31%) were diagnosed as possible AIS or TIA, 15 (7%) had intracranial hemorrhage while 59 patients (27%) were diagnosed as likely stroke mimics. Stroke mimics encountered included 13 (6%) metabolic encephalopathy, 11 (5%) seizures, 9 (4%) migraines, 3 (1%) substance abuse, 2 (1%) CNS tumor, 3 (1%) infectious etiology and 3 (1%) hypoglycemia. Fifty-four (24%) patients received non-thrombolytic treatments on MSUConclusionAbout one third of MSU encounters were not AIS initially, including intracranial hemorrhage and stroke mimics. MSU can be utilized to provide pre-hospital treatments in emergent neurological conditions other than AIS.     

Emergency radiologic approach to mastoid air cell fluid

Emergency Radiology - Mastoid air cell fluid is a commonly seen, but often dismissed finding. Given the location of the mastoid portion of the temporal bone and its location adjacent to vital...     

Molecularly imprinted polymeric coatings for sensitive and selective gravimetric detection of artemether

Monitoring antimalarial drugs is necessary for clinical assays, human health, and routine quality control practices in pharmaceutical industries. Herein, we present the development of sensor coatings based on molecularly imprinted polymers (MIPs) combined with quartz crystal microbalance (QCM) for sensitive and selective gravimetric detection of an antimalarial drug: artemether. The MIP coatings are synthesized by using artemether as the template in a poly(methacrylic acid-co-ethylene glycol dimethacrylate) matrix. Artemether-MIP and the non-imprinted polymer (NIP) control or reference layers are deposited on 10 MHz dual-electrode QCM by spin coating (187 ± 9 nm layer thickness after optimization). The coatings are characterized by FTIR spectroscopy and atomic force microscopy that reveal marked differences among the MIP and NIP. The MIP-QCM sensor exhibits high sensitivity (0.51 Hz ppm⁻¹) with sub-10 ppm detection and quantification limits. The MIP-QCM sensor also exhibits a 6-fold higher sensitivity compared to the NIP-QCM, and a dynamic working range of 30–100 ppm. The response time of MIP-QCM devices for a single cycle of analyte adsorption, signal saturation, and MIP regeneration is less than 2.5 min. The sensor also demonstrates selectivity factors of artemether-MIP of 2.2 and 4.1 compared to artemisinin and lumefantrine, respectively. Reversibility tests reveal less than 5% variation in sensor responses over three cycles of measurements at each tested concentration. The MIP-QCM showed lower detection limits than conventional HPLC-UV, and faster response time compared to HPLC-UV and liquid chromatography-mass spectrometry (LC-MS).

Chemical structures of the antimalarial drugs: artemisinin, artemether (a methyl ether derivative of artemisinin), and lumefantrine.     

Heme is an effector molecule for iron-dependent degradation of the bacterial iron response regulator (Irr) protein

The bacterial iron response regulator (Irr) protein mediates iron-dependent regulation of heme biosynthesis. Pulse-chase and immunoprecipitation experiments showed that Irr degraded in response to 6 microM iron with a half-life of approximately 30 min and that this regulated stability was the principal determinant of control by iron. Irr contains a heme regulatory motif (HRM) near its amino terminus. A role for heme in regulation was implicated by the retention of Irr in heme synthesis mutants in the presence of iron. Addition of heme to low iron (0.3 microM) cultures was sufficient for the disappearance of Irr in cells of the wild-type and heme mutant strains. Spectral and binding analyses of purified recombinant Irr showed that the protein bound heme with high affinity and caused a blue shift in the absorption spectrum of heme to a shorter wavelength. A Cys(29) --> Ala substitution within the HRM of Irr (IrrC29A) abrogated both high affinity binding to heme and the spectral blue shift. In vivo turnover experiments showed that, unlike wild-type Irr, IrrC29A was stable in the presence of iron. We conclude that iron-dependent degradation of Irr involves direct binding of heme to the protein at the HRM. The findings implicate a regulatory role for heme in protein degradation and provide direct evidence for a functional HRM in a prokaryote.     

β-Hydroxybutyrate protects from alcohol-induced liver injury via a Hcar2-cAMP dependent pathway

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