Structural Basis for Rabbit Hemorrhagic Disease Virus Antibody Specificity.

Rabbit hemorrhagic disease virus (RHDV) typically causes a fatal disease in rabbits. In Australia, RHDV was imported to control the feral rabbit population, while it poses a severe threat to native rabbits in other countries. RHDV variants are genetically diverse and serological studies using antibodies isolated from infected rabbits or raised against RHDV virus-like particles (VLPs) have found RHDV variants antigenically distinct. In this study, we determined the X-ray crystal structure of an RHDV GI.2 (N11 strain) protruding (P) domain in complex with a diagnostic monoclonal antibody (2D9) Fab. We showed that 2D9 interacted with conserved and variable residues on top of the P domain with nanomolar affinity. To better illustrate 2D9 specificity, we determined the X-ray crystal structure of an RHDV GI.1b (Ast89 strain) that was a 2D9 non-binder. Structural analysis indicated that amino acid substitutions on the GI.1b P domain likely restricted 2D9 binding. Interestingly, a model of the GI.2 P domain-Fab complex superimposed onto a cryo-EM structure of an RHDV VLP revealed that 2D9 Fab molecules clashed with neighboring Fabs and indicated that there was a reduced antibody binding occupancy. Moreover, the RHDV GI.2 histo-blood group antigen (HBGA) co-factor binding site appeared obstructed when 2D9 was modeled on the VLP and suggested that 2D9 might also function by blocking HBGA attachment. Overall, this new data provides the first structural basis of RHDV antibody specificity and explains how amino acid variation at the binding site likely restricts 2D9 cross-reactivity. IMPORTANCE Isolated RHDV antibodies have been used for decades to distinguish between antigenic variants, monitor temporal capsid evolution, and examine neutralizing capacities. In this study, we provided the structural basis for an RHDV GI.2 specific diagnostic antibody (2D9) binding and reveal that a small number of amino acid substitutions at the binding site could differentiate between RHDV GI.2 and GI.1b. This novel structural information provides a framework for understanding how RHDV displays a specific antigenic epitope and engages an antibody at the atomic level. Importantly, part of the 2D9 binding region was earlier reported to contain a neutralizing epitope and our structural modeling as well as recent human norovirus antibody-mediated neutralization studies, suggest that the 2D9 antibody has the potential to block HBGA attachment. These new findings should aid in characterizing antigenic variants and advance the development of novel monoclonal antibodies for diagnostics and therapeutics.

Nanobody-Mediated Neutralization Reveals an Achilles Heel for Norovirus.

Human norovirus frequently causes outbreaks of acute gastroenteritis. Although discovered more than five decades ago, antiviral development has, until recently, been hampered by the lack of a reliable human norovirus cell culture system. Nevertheless, a lot of pathogenesis studies were accomplished using murine norovirus (MNV), which can be grown routinely in cell culture. In this study, we analyzed a sizeable library of nanobodies that were raised against the murine norovirus virion with the main purpose of developing nanobody-based inhibitors. We discovered two types of neutralizing nanobodies and analyzed the inhibition mechanisms using X-ray crystallography, cryo-electron microscopy (cryo-EM), and cell culture techniques. The first type bound on the top region of the protruding (P) domain. Interestingly, this nanobody binding region closely overlapped the MNV receptor-binding site and collectively shared numerous P domain-binding residues. In addition, we showed that these nanobodies competed with the soluble receptor, and this action blocked virion attachment to cultured cells. The second type bound at a dimeric interface on the lower side of the P dimer. We discovered that these nanobodies disrupted a structural change in the capsid associated with binding cofactors (i.e., metal cations/bile acid). Indeed, we found that capsids underwent major conformational changes following addition of Mg2+ or Ca2+ Ultimately, these nanobodies directly obstructed a structural modification reserved for a postreceptor attachment stage. Altogether, our new data show that nanobody-based inhibition could occur by blocking functional and structural capsid properties.IMPORTANCE This research discovered and analyzed two different types of MNV-neutralizing nanobodies. The top-binding nanobodies sterically inhibited the receptor-binding site, whereas the dimeric-binding nanobodies interfered with a structural modification associated with cofactor binding. Moreover, we found that the capsid contained a number of vulnerable regions that were essential for viral replication. In fact, the capsid appeared to be organized in a state of flux, which could be important for cofactor/receptor-binding functions. Blocking these capsid-binding events with nanobodies directly inhibited essential capsid functions. Moreover, a number of MNV-specific nanobody binding epitopes were comparable to human norovirus-specific nanobody inhibitors. Therefore, this additional structural and inhibition information could be further exploited in the development of human norovirus antivirals.

A mammalian pre-mRNA 5' end capping quality control mechanism and an unexpected link of capping to pre-mRNA processing.

Recently, we reported that two homologous yeast proteins, Rai1 and Dxo1, function in a quality control mechanism to clear cells of incompletely 5' end-capped messenger RNAs (mRNAs). Here, we report that their mammalian homolog, Dom3Z (referred to as DXO), possesses pyrophosphohydrolase, decapping, and 5'-to-3' exoribonuclease activities. Surprisingly, we found that DXO preferentially degrades defectively capped pre-mRNAs in cells. Additional studies show that incompletely capped pre-mRNAs are inefficiently spliced at all introns, a fact that contrasts with current understanding, and are also poorly cleaved for polyadenylation. Crystal structures of DXO in complex with substrate mimic and products at a resolution of up to 1.5Å provide elegant insights into the catalytic mechanism and molecular basis for their three apparently distinct activities. Our data reveal a pre-mRNA 5' end capping quality control mechanism in mammalian cells, indicating DXO as the central player for this mechanism, and demonstrate an unexpected intimate link between proper 5' end capping and subsequent pre-mRNA processing.

Structural Basis for Human Norovirus Capsid Binding to Bile Acids.

A recently developed human norovirus cell culture system revealed that the presence of bile enhanced or was an essential requirement for the growth of certain genotypes. Before this discovery, histo-blood group antigens (HBGAs) were the only well-studied cofactor known for human noroviruses, and there was evidence that several genotypes poorly bound HBGAs. Therefore, the purpose of this study was to investigate how human norovirus capsids interact with bile acids. We found that bile acids had low-micromolar affinities for GII.1, GII.10, and GII.19 capsids but did not bind GI.1, GII.3, GII.4, or GII.17. We showed that bile acid bound at a partially conserved pocket on the norovirus capsid-protruding (P) domain using X-ray crystallography. Amino acid sequence alignment and structural analysis delivered an explanation of selective bile acid binding. Intriguingly, we discovered that binding of the bile acid was the critical step to stabilize several P domain loops that optimally placed an essential amino acid side chain (Asp375) to bind HBGAs in an otherwise HBGA nonbinder (GII.1). Furthermore, bile acid enhanced HBGA binding for a known HBGA binder (GII.10). Altogether, these new data suggest that bile acid functions as a loop-stabilizing regulator and enhancer of HBGA binding for certain norovirus genotypes.IMPORTANCE Given that human norovirus virions likely interact with bile acid during a natural infection, our evidence that an HBGA nonbinder (GII.1) can be converted to an HBGA binder after bile acid binding is of major significance. Our data provide direct evidence that, like HBGAs, bile acid interaction on the capsid is an important cofactor for certain genotypes. However, more unanswered questions seem to arise from these new discoveries. For example, is there an association between the bile acid requirement and the prevalence of certain genotypes? That is, the GII.1 and GII.10 (bile acid binders) genotypes rarely caused outbreaks, whereas the GII.4 and GII.17 genotypes (bile acid nonbinders) were responsible for large epidemics. Therefore, it seems plausible that certain genotypes require bile acids, whereas others have modified their bile acid requirements on the capsid.

Structural Basis of Nanobodies Targeting the Prototype Norovirus.

Human norovirus infections are a major disease burden. In this study, we analyzed three new norovirus-specific Nanobodies that interacted with the prototype human norovirus (i.e., genogroup I genotype 1 [GI.1]). We showed that the Nanobodies bound on the side (Nano-7 and Nano-62) and top (Nano-94) of the capsid-protruding (P) domain using X-ray crystallography. Nano-7 and Nano-62 bound at a similar region on the P domain, but the orientations of these two Nanobodies clashed with the shell (S) domain and neighboring P domains on intact particles. This finding suggested that the P domains on the particles should shift in order for Nano-7 and Nano-62 to bind to intact particles. Interestingly, both Nano-7 and Nano-94 were capable of blocking norovirus virus-like particles (VLPs) from binding to histo-blood group antigens (HBGAs), which are important cofactors for norovirus infection. Previously, we showed that the GI.1 HBGA pocket could be blocked with the soluble human milk oligosaccharide 2-fucosyllactose (2'FL). In the current study, we showed that a combined treatment of Nano-7 or Nano-94 with 2'FL enhanced the blocking potential with an additive (Nano-7) or synergistic (Nano-94) effect. We also found that GII Nanobodies with 2'FL also enhanced inhibition. The Nanobody inhibition likely occurred by different mechanisms, including particle aggregation or particle disassembly, whereas 2'FL blocked the HBGA binding site. Overall, these new data showed that the positive effect of the addition of 2'FL was not limited to a single mode of action of Nanobodies or to a single norovirus genogroup.IMPORTANCE The discovery of vulnerable regions on norovirus particles is instrumental in the development of effective inhibitors, particularly for GI noroviruses that are genetically diverse. Analysis of these GI.1-specific Nanobodies has shown that similar to GII norovirus particles, the GI particles have vulnerable regions. The only known cofactor region, the HBGA binding pocket, represents the main target for inhibition. With a combination treatment, i.e., the addition of Nano-7 or Nano-94 with 2'FL, the effect of inhibition was increased. Therefore, combination drug treatments might offer a better approach to combat norovirus infections, especially since the GI genotypes are highly diverse and are continually changing the capsid landscape, and few conserved epitopes have so far been identified.

Atomic Structure of the Murine Norovirus Protruding Domain and Soluble CD300lf Receptor Complex.

Human noroviruses are the leading cause of acute gastroenteritis in humans. Noroviruses also infect animals, such as cows, mice, cats, and dogs. How noroviruses bind and enter host cells is still incompletely understood. Recently, the type I transmembrane protein CD300lf was identified as the murine norovirus receptor, yet it is unclear how the virus capsid and receptor interact at the molecular level. In this study, we determined the X-ray crystal structure of the soluble CD300lf (sCD300lf) and the murine norovirus capsid protruding domain complex at a 2.05-Å resolution. We found that the sCD300lf-binding site is located on the topside of the protruding domain and involves a network of hydrophilic and hydrophobic interactions. sCD300lf locked nicely into a complementary cavity on the protruding domain that is additionally coordinated with a positive surface charge on sCD300lf and a negative surface charge on the protruding domain. Five of six protruding domain residues interacting with sCD300lf were maintained between different murine norovirus strains, suggesting that sCD300lf was capable of binding to a highly conserved pocket. Moreover, a sequence alignment with other CD300 paralogs showed that the sCD300lf-interacting residues were partially conserved in CD300ld but variable in other CD300 family members, consistent with previously reported infection selectivity. Overall, these data provide insights into how a norovirus engages a protein receptor and will be important for a better understanding of selective recognition and norovirus attachment and entry mechanisms.IMPORTANCE Noroviruses exhibit exquisite host range specificity due to species-specific interactions between the norovirus capsid protein and host molecules. Given this strict host range restriction, it has been unclear how the viruses are maintained within a species between relatively sporadic epidemics. While much data demonstrate that noroviruses can interact with carbohydrates, recent work has shown that expression of the protein CD300lf is both necessary and sufficient for murine norovirus infection of mice and binding of the virus to permissive cells. Importantly, the expression of this murine protein by human cells renders them fully permissive for murine norovirus infection, indicating that at least in this case, host range restriction is determined by molecular events that control receptor binding and entry. Defining the atomic-resolution interactions between the norovirus capsid protein and its cognate receptor is essential for a molecular understanding of host-range restriction and norovirus tropism.

Diagnostic yield of neuroimaging in syncope patients without high-risk symptoms indicating neurological syncope.

OBJECTIVES: Diagnostic tests are widely used for patients with syncope in the emergency department (ED). This study aimed to determine the diagnostic yield of neuroimaging in patients with syncope without high-risk symptoms. METHODS: Adult patients who presented to the ED with syncope in 2016 were screened retrospectively. Patients who suffered from mild head trauma due to syncope were also included. Patients with neurological examination findings (confusion, amnesia, focal neurological deficit, severe headache, dizziness, nausea and vomiting), patients on anticoagulants, patients with known intracranial malignancies and those whose loss of consciousness was attributed to reasons other than syncope were excluded from the study. RESULTS: A total of 1114 patients were included in the study. The median age was 48 years (IQR = 34-66 years) and 576 (51.7%) of the patients were male. The neuroimaging tests performed were cranial computerized tomography (CT) in 694 (62.3%) cases and magnetic resonance imaging (MRI) in 114 (10.2%) cases. Mild head trauma due to syncope was observed in 116 (10.4%) patients. None of the neuroimaging studies revealed any clinically significant findings. CONCLUSION: Neuroimaging is not beneficial in patients whose medical history and physical examination do not indicate neurogenic syncope, even if the patient has mild head trauma.

Fucose-Functionalized Precision Glycomacromolecules Targeting Human Norovirus Capsid Protein.

Norovirus infection is the major cause of nonbacterial gastroenteritis in humans and has been the subject of numerous studies investigating the virus's biophysical properties and biochemical function with the aim of deriving novel and highly potent entry inhibitors to prevent infection. Recently, it has been shown that the protruding P domain dimer (P-dimer) of a GII.10 Norovirus strain exhibits two new binding sites for l-fucose in addition to the canonical binding sites. Thus, these sites provide a novel target for the design of multivalent fucose ligands as entry inhibitors of norovirus infections. In this current study, a first generation of multivalent fucose-functionalized glycomacromolecules was synthesized and applied as model structures to investigate the potential targeting of fucose binding sites in human norovirus P-dimer. Following previously established solid phase polymer synthesis, eight precision glycomacromolecules varying in number and position of fucose ligands along an oligo(amidoamine) backbone were obtained and then used in a series of binding studies applying native MS, NMR, and X-ray crystallography. We observed only one fucose per glycomacromolecule binding to one P-dimer resulting in similar binding affinities for all fucose-functionalized glycomacromolecules, which based on our current findings we attribute to the overall size of macromolecular ligands and possibly to steric hindrance.

The diagnostic and prognostic value of the optic nerve sheath diameter on CT for diagnosis spontaneous subarachnoid hemorrhage.

INTRODUCTION: The aim of this study was to investigate the relationship between the optic nerve sheath diameter (ONSD) measured on non-contrast head computed tomography (CT) and the diagnosis and prognosis of spontaneous subarachnoid hemorrhage (SAH) on emergency department (ED) patients. METHOD: We used a matched control group of patients with the same age and gender who were diagnosed in the ED with spontaneous SAH and who admitted to the ED with headache. Four emergency medicine attending physicians made the ONSD measurements. For measurements, the 3-mm posterior location where the optic nerve enters the eyeball was used. RESULTS: This study was done with 61 spontaneous SAHs with an equal number of control patients. The median ONSD for control and spontaneous SAH groups was 5.76 [interquartile range (IQR): 0.96] mm and 6.72 (IQR: 1.42) mm, respectively (p<0.001). The area under the receiver operating characteristic curve was determined as 0.791 (confidence interval 95% 0.710-0.872). At an ONSD threshold value of 6.1 mm, the sensitivity and specificity of SAH was 72%. There was no significant relationship between ONSD and in-hospital mortality in spontaneous SAH patients (p>0.05). The intra-class correlation coefficients for inter and intra-rater reliability were 0.84 and 0.95, respectively. CONCLUSION: In patients with spontaneous SAH, the ONSD measured in the orbital sections of a head CT is strongly correlated with a SAH diagnosis. Assessment of ONSD in head CTs taken with spontaneous SAH suspicion may contribute to the diagnoses of spontaneous SAH.

Crystal structure of the human symplekin-Ssu72-CTD phosphopeptide complex.

Symplekin (Pta1 in yeast) is a scaffold in the large protein complex that is required for 3'-end cleavage and polyadenylation of eukaryotic messenger RNA precursors (pre-mRNAs); it also participates in transcription initiation and termination by RNA polymerase II (Pol II). Symplekin mediates interactions between many different proteins in this machinery, although the molecular basis for its function is not known. Here we report the crystal structure at 2.4 Å resolution of the amino-terminal domain (residues 30-340) of human symplekin in a ternary complex with the Pol II carboxy-terminal domain (CTD) Ser 5 phosphatase Ssu72 (refs 7, 10-17) and a CTD Ser 5 phosphopeptide. The N-terminal domain of symplekin has the ARM or HEAT fold, with seven pairs of antiparallel α-helices arranged in the shape of an arc. The structure of Ssu72 has some similarity to that of low-molecular-mass phosphotyrosine protein phosphatase, although Ssu72 has a unique active-site landscape as well as extra structural features at the C terminus that are important for interaction with symplekin. Ssu72 is bound to the concave face of symplekin, and engineered mutations in this interface can abolish interactions between the two proteins. The CTD peptide is bound in the active site of Ssu72, with the pSer 5-Pro 6 peptide bond in the cis configuration, which contrasts with all other known CTD peptide conformations. Although the active site of Ssu72 is about 25 Å from the interface with symplekin, we found that the symplekin N-terminal domain stimulates Ssu72 CTD phosphatase activity in vitro. Furthermore, the N-terminal domain of symplekin inhibits polyadenylation in vitro, but only when coupled to transcription. Because catalytically active Ssu72 overcomes this inhibition, our results show a role for mammalian Ssu72 in transcription-coupled pre-mRNA 3'-end processing.

Accuracy of bedside ultrasonography for the diagnosis of finger fractures.

OBJECTIVE: Diagnosis of bone fractures by ultrasonography is becoming increasingly popular in emergency medicine practice. We aimed to determine the diagnostic sensitivity and specificity of point-of-care ultrasonography (PoCUS) compared with plain radiographs in proximal and middle phalanx fractures. METHODS: Between August 2012 and July 2013, adult patients presenting to our emergency department with a possible (by clinical evaluation) proximal or middle phalanx fracture of finger were invited to participate in this prospective cohort study. From those granting consent to participate, anteroposterior and lateral radiographs were obtained. PoCUS was then performed by emergency physicians blinded to the radiograph results. The criterion standard test for diagnosis was radiograph interpretation by an orthopedic surgeon blinded to the ultrasonographic findings. RESULTS: During the study period, 212 patients with an injury to the proximal or middle phalanx presented to the emergency department. Of these, 93 patients met exclusion criteria; thus, data were analyzed from the remaining 119 patients. Fracture prevalence was 24.3%. Diagnostic sensitivity of PoCUS was 79.3% (95% confidence interval [CI], 59.7%-91.2%), specificity was 90% (95% CI, 81.4%-95.0%), positive predictive value was 71.8% (95% CI, 53.0%-85.6%), negative predictive value was 93.1% (95% CI, 85.0%-97.1%), positive likelihood ratio was 7.93 (95% CI, 4.15-15), and negative likelihood ratio was 0.23 (95% CI, 0.11-0.47). CONCLUSION: Emergency physician-performed PoCUS was moderately sensitive and specific for diagnosing proximal and middle phalanx fractures.

Sensitivity and specificity of bedside ultrasonography in the diagnosis of fractures of the fifth metacarpal.

OBJECTIVES: Ultrasonography is becoming increasingly common in the diagnosis of fracture in emergency medicine. The aim of our study was to investigate the diagnostic accuracy of sonographic examinations for diagnosing fifth metacarpal fractures. METHODS: A prospective study was performed of consecutive patients aged >14 years admitted to the emergency department with hand trauma and tenderness over the fifth metacarpal. Anteroposterior and oblique plain x-rays were taken on all patients. Emergency physicians performed bedside sonographic examination. The x-rays were reported by an orthopaedic surgeon who was blinded to the sonographic examination findings. The orthopaedic surgeon's report was considered the gold standard unless a CT scan was performed. In the single case where this occurred, the CT scan report was considered the gold standard. RESULTS: Eighty one patients were included in the study, 39 of whom had fractures. Sonographic examination identified the fractures in 38 patients. One occult fracture undetected by plain radiography, later shown on CT scan, was identified by sonographic examination. There were three cases with false positive ultrasound findings. The sensitivity of the diagnosis of fifth metacarpal fractures by ultrasonography was 97.4% (95% CI 84.9% to 99.9%), specificity was 92.9% (95% CI 79.4% to 98.1%), positive likelihood ratio (LR) was 14 (95% CI 4.58 to 41), negative LR was 0.03 (95% CI 0.00 to 0.19), negative predictive value was 97.5% (95% CI 85.3% to 99.9%) and positive predictive value was 92.6% (95% CI 79% to 98.1%). CONCLUSIONS: Sonographic examination can be used as an effective diagnostic tool in patients with fifth metacarpal trauma.

Retrograde cerebral air embolism.

Pneumocephalus is a clinical condition caused by dysbarism, trauma, and iatrogenic causes. The most common iatrogenic causes of pneumocephalus are major interventions as a neurosurgery and cardiovascular operations, endoscopy, and minor interventions as a peripheral and central venous access. Especially during insertion of central venous line and intravenous drug and fluid infusion, the venous air embolism may occur in emergency department. In these patients, retrograde pneumocephalus occurs as a result of the air entering the right atrium to the brain. Clinical effects of the air delivery rates are known to be more specific than the total amount of air. In general, intravenous administration of 300 to 500 mL air in the speed of 100 mL/min is considered to be lethal. Large amounts of air embolism can cause hypotension and acute circulatory collapse with intracardiac obstruction. The most common symptoms of venous air embolism are anxiety, dyspnea, chest pain, cyanosis, tachycardia, tachypnea, headache, confusion, agitation, syncope, slurred speech, blurred vision, seizures, and ataxia. The mortality of pneumocephalus caused by central venous catheters in patients presented with symptoms of focal neurologic was 8%, whereas the mortality of pneumocephalus in patients presented with encephalopathy was 36%. In our report, a case of pneumocephalus secondary to disconnection of catheter cap in chronic renal failure patient who has hemodialysis via catheter has been presented.

The effect of fresh frozen plasma transfusion on international normalized ratio in emergency department patients.

BACKGROUND: There are few studies researching the effect of fresh frozen plasma (FFP) transfusion on international normalized ratio (INR) in patients with coagulation abnormality. OBJECTIVE: This study's aim was to determine the effect of FFP transfusion on INR as calculated pretransfusion. In addition, patients were grouped according to pretransfusion INR to determine the improvement in INR per unit of FFP. METHODS: Adult patients who had been admitted to our Emergency Department (ED) with coagulation abnormality and received an FFP transfusion, and had pre- and posttransfusion coagulation tests performed, were included in the study. Patients were categorized into five groups according to their pretransfusion INR levels. Improvement in INR per unit of FFP-transfused values (Δ INR 1 unit FFP) was determined for each group. RESULTS: Eighty-seven patients were entered into the study, and were administered a total of 199 units of FFP. Δ INR 1 unit FFP value was 0.03 ± 0.13 for patients whose pretransfusion INR level was under 2; 0.77 ± 0.47 for those between 2 and 5; 2.14 ± 0.63 for those between 5 and 9; 3.34 ± 0.89 for those between 9 and 12; and 4.63 ± 1.99 for those over 12. A very strong positive correlation was found between pretransfusion INR and Δ INR 1 unit FFP (p < 0.001, r = 0.957). CONCLUSION: A significant improvement in INR was observed in patients with higher pretransfusion INR. While determining FFP dose for patients admitted to the ED due to coagulation defect, pretransfusion INR value should be taken into account.

The Relation of End-Tidal CO 2 Values With Infarct Volume and Early Prognosis in Patients With Acute Ischemic Stroke.

BACKGROUND: The aim of this study is to reveal the relationship between end-tidal CO 2 (EtCO 2 ) values with infarct volume and early prognosis in patients diagnosed with acute ischemic stroke in the emergency department. MATERIALS AND METHODS: This prospective cross-sectional study was conducted in a tertiary hospital. The demographics, characteristics, EtCO 2 , volume of the stroke area on diffusion-weighted magnetic resonance imaging and the modified Rankin Scale (mRS) of the patients were recorded. The values calculated at admission and at discharge were labeled as "mRS-1" and "mRS-2," respectively, and the mRS-2 measurement was used as a prognostic indicator. The "good" and the "poor" functional outcomes were defined as mRS ≤2 and mRS >2, respectively. Correlations between levels of EtCO 2 and infarct volume, mRS were calculated. RESULTS: In total, 44 patients were included in the study. The median age of the patients was 69 years (interquartile range; 16; min-max: 35 to 88 y) and 68.2% of them were male. In the univariate logistic regression models of the mRS-2 [0 to 2 (0) and 3 to 6 (1)], all variables were not statistically significant to predict mRS-2 group. There were statistically significant differences in EtCO 2 values between mRS-1 ( P =0.03) and mRS-2 ( P =0.04). A negative moderate correlation was found between EtCO 2 and mRS-2 ( r =-0.410; P =0.006). The correlation between EtCO 2 and infarct volume was not statistically significant ( r =-0.256; P =0.093). CONCLUSIONS: This study highlights the importance of capnography follow-up of patients with acute ischemic stroke. In patients with acute ischemic stroke, the EtCO 2 value measured at the time of admission is lower in the group with high mRS at both admission and discharge.

Paramedic-performed Focused Assessment with Sonography in Trauma (FAST) in the emergency department.

BACKGROUND: Our objective was to evaluate the accuracy of paramedic-performed Focused Assessment with Sonography in Trauma (PFAST) for detection of free fluid in patients admitted to the Emergency Department (ED) following trauma. METHODS: After four hours of didactic and four hours of hands-on training, four paramedics prospectively evaluated trauma patients. Our gold standard was the official radiologist reports of ultrasonography and computerized abdominal tomography (CAT). The sensitivity, specificity, positive and negative likelihood ratios, and diagnostic odds ratio of PFAST were calculated and analyzed using SPSS 15.0 with ?2 testing. RESULTS: One hundred and twenty-seven patients were evaluated by the paramedics. Fourteen patients had positive free fluid in the abdomen. Of these, 11 were corroborated by radiology reports and CAT (true positives), and three were found to be negative (false positives). In 113 cases, PFAST was negative for free fluid. Of these, 111 were determined not to have free fluid (true negatives), whereas free fluid was detected by CAT in 2 (false negatives). The sensitivity, specificity, positive and negative likelihood ratios, and diagnostic odds ratio of PFAST were 84.62, 97.37, 32.15, 0.16, and 203.50, respectively. CONCLUSION: Our study shows that paramedics can perform FAST in hospital Eds with a high degree of accuracy.

Comparison of Ultrasound-Guided Central Venous Catheter Placement Techniques Using an Easily Made Simulator Model.

OBJECTIVES: Central venous catheter (CVC) placement is an important procedure which is frequently performed in the emergency department (ED) and can cause serious complications. The aim of this study is to introduce a simulation-based tissue model for ultrasound (US)-guided central venous access practices and to compare the effectiveness of static and dynamic US techniques through this model. METHODS: This was a prospective study on US-guided CVC placement techniques simulated with a chicken tissue model. This model is based on the principle of placing two cylindrical balloons filled with colored water (red for arterial and blue for venous) between a raw chicken breast and wrapping the formed structure with plastic wrap. The study was conducted in an academic tertiary care hospital with Emergency Medicine (EM) residents who have received basic US training, including vascular access procedures. All participants performed simulated CVC placement procedures with both static and dynamic US techniques. At the end of the study, the practitioners were asked to rate usefulness of these techniques between one and ten (one was the lowest and ten was the highest score). RESULTS: A total of 32 EM residents were included in the study. Their median age was 29 (IQR = 27 - 31) years and 72% of them were male. Their median duration in ED was 19 (IQR = 12 - 34) months. According to the results of simulated CVC placement procedures, there was no significant difference between the static and dynamic US techniques in terms of puncture numbers, procedure durations, and success rates. However, according to the usefulness scores given by the practitioners, the dynamic US technique was found to be more useful (P < .001). CONCLUSIONS: The chicken tissue model is a convenient tool for simulating US-guided CVC placement procedures. The dynamic US technique is considered to be more useful in this field than the static technique, but the results of practitioner-dependent practices may not always support this generalization.

Pain management practices in the emergency departments in Turkey.

OBJECTIVES: This study aimed to evaluate pain management practices in the emergency departments (EDs) in Turkey and to evaluate the prevalence and etiologies of oligoanalgesia to identify possible improvement strategies. METHODS: This multicenter cross-sectional observational study was conducted in 10 tertiary care hospitals in Turkey. Patients who were admitted to the ED with pain chief complaints were included in the study. Both patients and physicians were surveyed with two separate forms by the research associates, respectively. The patient survey collected data about the pain and the interventions from the patients' perspective. The pain was evaluated using the Numerical Rating Scale. The physician survey collected data to assess the differences between study centers on pain management strategies and physician attitudes in pain management. RESULTS: Ten emergency physicians and 740 patients (male/female: 365/375) enrolled in the study. The median pain score at admission at both triage and ED was 7 (interquartile range: 5-8). The most frequent type of pain at admission was headache (n = 184, 24.7%). The most common analgesics ordered by physicians were nonsteroidal anti-inflammatory drugs (n = 505, 67.9%), and the most frequent route of administration was intramuscular injection (n = 396, 53.2%). About half of the patients (n = 366, 49.2%) received analgesics 10-30 min from ED admission. The posttreatment median pain score decreased to 3 (P < 0.001). About 79.2% of patients did not need a second analgesic administration (n = 589), and opioid analgesics were the most frequently administered analgesic if the second application was required. Physicians prescribed an analgesic at discharge from the ED in 55.6% of the patients (n = 414) and acute pain was present in 7.5% (n = 56) of the patients. CONCLUSION: Our study on the pain management practices in the EDs in Turkey suggested that high rate of intramuscular analgesic use and long emergency room stay durations are issues that should constitute the focus of our quality improvement efforts in pain management.

The role of cobalt-albumin binding analysis in the diagnosis of experimental abdominal compartment syndrome in rabbits.

BACKGROUND: The purpose of our study was to examine the role of cobalt-albumin binding assay (CABA) for the early diagnosis of abdominal compartment syndrome (ACS). METHODS: Twenty-four anesthetized and ventilated rabbits were randomly assigned to four groups as 1 to 4, with each group comprised of six animals. Intraabdominal hypertension of 25 mmHg was induced for 15, 30, 45, and 60 minutes by insufflation in the four groups, respectively. Five ml of blood was drawn from each animal before the animals were sacrificed. A CABA test was performed on the samples and results were compared with pathologic diagnosis of intestinal samples shown as a score of damage severity values. RESULTS: Ischemia-modified albumin (IMA) in Group 4 was significantly higher than in Group 1 and Group 2 (0.65 ± 0.16, 0.60 ± 0.25 and 0.61 ± 0.14, respectively; p < 0.05). However, there was no significant difference between the IMA of Group 3 and Group 4. Score of damage severity values reached statistically significant levels in Group 4 compared with Group 1 and Group 2 (p < 0.004 and 0.006, respectively) and in Group 3 compared with Group 1 (p < 0.004). There was also a statistically significant difference between Groups 1 and 2 (p < 0.004). CONCLUSION: CABA plays an important role in the early diagnosis of ACS at the beginning of intestinal ischemia.