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1.
J Virol ; 96(22): e0121722, 2022 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-36326275

RESUMO

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.


Assuntos
Especificidade de Anticorpos , Antígenos de Grupos Sanguíneos , Infecções por Caliciviridae , Vírus da Doença Hemorrágica de Coelhos , Animais , Coelhos , Antígenos de Grupos Sanguíneos/metabolismo , Infecções por Caliciviridae/veterinária , Epitopos/metabolismo
2.
Neurologist ; 27(6): 309-312, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-35051967

RESUMO

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.


Assuntos
AVC Isquêmico , Acidente Vascular Cerebral , Humanos , Masculino , Idoso , Feminino , Estudos Prospectivos , Estudos Transversais , Resultado do Tratamento , Acidente Vascular Cerebral/diagnóstico , Prognóstico , Infarto
3.
Turk J Emerg Med ; 21(4): 189-197, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34849431

RESUMO

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.

4.
Prehosp Disaster Med ; 36(3): 301-305, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33818350

RESUMO

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.


Assuntos
Cateterismo Venoso Central , Cateteres Venosos Centrais , Adulto , Humanos , Masculino , Estudos Prospectivos , Ultrassonografia , Ultrassonografia de Intervenção
5.
Neurologist ; 25(4): 85-88, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32618835

RESUMO

OBJECTIVES: Dizziness is a common symptom among emergency department (ED) patients and is often associated with benign processes. The aim of this study was to investigate the incidence of severe central neurological pathologies in isolated dizziness cases and the diagnostic efficiency of neuroimaging studies. METHODS: All applications for isolated dizziness to an academic ED between January 1, 2011, and December 31, 2017 were retrospectively reviewed. The frequency of these admissions, the demographic data of the patients, the results of cranial computed tomography (CT) and diffusion-weighted magnetic resonance imaging (DW-MRI) studies, and the central neurological causes of isolated dizziness were recorded. RESULTS: The percentage of patients with isolated dizziness among all ED admissions was 2.5% (29,510/1,190,857). The median age of these patients was 52 years (interquartile range: 38 to 66) and 58% were female. During the study period, the rate of neuroimaging studies for isolated dizziness increased year by year, and a total of 6406 (21.7%) cranial CTs and 2896 (9.8%) DW-MRIs were performed. The diagnostic yield of neuroimaging studies was 0.6% for cranial CT and 3.9% for DW-MRI. Central neurological disorders were detected in 143 (0.48%) patients with isolated dizziness. The most common causes were posterior circulation ischemic strokes (47.5%), other ischemic strokes (18.9%), vertebrobasilar insufficiency (10.5%), and transient ischemic attack (8.4%). CONCLUSIONS: Isolated dizziness is rarely associated with central neurological pathologies. Neuroimaging studies, especially cranial CT, have low diagnostic yield in isolated dizziness and should therefore not be routine in the evaluation process.


Assuntos
Doenças do Sistema Nervoso Central/diagnóstico por imagem , Doenças do Sistema Nervoso Central/epidemiologia , Imagem de Difusão por Ressonância Magnética/normas , Tontura/diagnóstico por imagem , Tontura/epidemiologia , Neuroimagem/normas , Tomografia Computadorizada por Raios X/normas , Centros Médicos Acadêmicos , Adulto , Idoso , Infarto Encefálico/diagnóstico por imagem , Infarto Encefálico/epidemiologia , Serviço Hospitalar de Emergência , Feminino , Humanos , Incidência , Ataque Isquêmico Transitório/diagnóstico por imagem , Ataque Isquêmico Transitório/epidemiologia , AVC Isquêmico/diagnóstico por imagem , AVC Isquêmico/epidemiologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Insuficiência Vertebrobasilar/diagnóstico por imagem , Insuficiência Vertebrobasilar/epidemiologia
6.
J Virol ; 94(13)2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32321816

RESUMO

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.


Assuntos
Infecções por Caliciviridae/terapia , Norovirus/genética , Anticorpos de Domínio Único/farmacologia , Sítios de Ligação/genética , Capsídeo/metabolismo , Proteínas do Capsídeo/metabolismo , Microscopia Crioeletrônica/métodos , Cristalografia por Raios X/métodos , Epitopos/metabolismo , Gastroenterite/metabolismo , Norovirus/imunologia , Norovirus/patogenicidade , Ligação Proteica/genética , Conformação Proteica , Domínios Proteicos/genética , Anticorpos de Domínio Único/imunologia , Anticorpos de Domínio Único/metabolismo , Vírion/metabolismo
7.
Prehosp Disaster Med ; 35(2): 229-230, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32036812

RESUMO

BACKGROUND: End-tidal carbon dioxide (EtCO2) is a non-invasive method giving information about the perfusion, ventilation, and metabolic condition of patients. The correlation was studied here between the metabolic (pH, bicarbonate) values and EtCO2 during the treatment of diabetic ketoacidosis (DKA). CASE REPORT: A 23-year-old male patient with diabetes mellitus was admitted to the emergency department (ED) with the complaints of nausea, vomiting, and fever. The patient with a diagnosis of DKA was continuously monitored with EtCO2; EtCO2 was correlated with serum bicarbonate (HCO3; r = 0.96; P < .001) and pH (r = 0.93; P < .001). CONCLUSION: Continuous EtCO2 monitoring should be considered by emergency physicians in the metabolic monitoring of the patients as it is an easy-to-use, non-invasive, and cost-effective method that provides instant and reliable information.


Assuntos
Dióxido de Carbono/análise , Cetoacidose Diabética/diagnóstico , Capnografia , Cetoacidose Diabética/metabolismo , Diagnóstico Diferencial , Serviço Hospitalar de Emergência , Humanos , Masculino , Monitorização Fisiológica , Adulto Jovem
8.
Acta Crystallogr D Struct Biol ; 75(Pt 5): 498-504, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31063152

RESUMO

Bovine meat and milk factors (BMMFs) are circular, single-stranded episomal DNAs that have been detected in bovine meat and milk products. BMMFs are thought to have roles in human malignant and degenerative diseases. BMMFs encode a replication initiator protein (Rep) that is actively transcribed and translated in human cells. In this study, a Rep WH1 domain encoded on a BMMF (MSBI1.176) isolated from a multiple sclerosis human brain sample was determined to 1.53 Šresolution using X-ray crystallography. The overall structure of the MSBI1.176 WH1 domain was remarkably similar to other Rep structures, despite having a low (28%) amino-acid sequence identity. The MSBI1.176 WH1 domain contained elements common to other Reps, including five α-helices, five ß-strands and a hydrophobic pocket. These new findings suggest that the MSBI1.176 Rep might have comparable roles and functions to other known Reps of different origins.


Assuntos
Encéfalo/metabolismo , DNA Helicases/química , DNA Helicases/metabolismo , Esclerose Múltipla/metabolismo , Plasmídeos/isolamento & purificação , Plasmídeos/metabolismo , Transativadores/química , Transativadores/metabolismo , Sequência de Aminoácidos , Animais , Bovinos , Cristalografia por Raios X , Humanos , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Domínios Proteicos , Homologia de Sequência
9.
Turk J Emerg Med ; 19(2): 87-89, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31073545

RESUMO

INTRODUCTION: Glenohumeral dislocation is the most commonly encountered dislocation in the emergency department. The most frequent complications of glenohumeral dislocation are rotator cuff tears and an increase in the risk of recurrent dislocation. Less common acute complications include fractures, neurological complications and vascular injuries. The incidence of axillary artery injury associated with shoulder dislocation is reported to be about 1-2%. CASE: An 81-year-old male presented to the emergency department with pain in the right shoulder after a fall. On physical examination, the shoulder was in slight abduction and external rotation. Shoulder movements were painful and there was a swelling in the axillary region which was tender to palpation. There was no sensory or motor deficit and the peripheral pulses were equal and palpable. Following the administration of analgesics, shoulder reduction was performed using the flexion-adduction-external rotation method. After reduction, the patient started complaining of axillary pain. On control examination, the patient did not have any motor or sensory deficits, but peripheral pulses were not palpable on the right arm. The right upper extremity computed tomography angiography, which was performed with the suspicion of vascular injury, revealed a right axillary artery rupture. CONCLUSION: Axillary artery injury accompanying anterior shoulder dislocation is a rare but serious condition which may result in limb loss and death.

10.
J Virol ; 93(6)2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30602609

RESUMO

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.


Assuntos
Infecções por Caliciviridae/imunologia , Norovirus/imunologia , Anticorpos de Domínio Único/imunologia , Sítios de Ligação/imunologia , Antígenos de Grupos Sanguíneos/imunologia , Capsídeo/imunologia , Proteínas do Capsídeo/imunologia , Cristalografia por Raios X/métodos , Epitopos/imunologia , Escherichia coli/virologia , Ligação Proteica/imunologia
11.
Am J Emerg Med ; 37(2): 228-230, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-29802003

RESUMO

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.


Assuntos
Neuroimagem , Síncope/diagnóstico por imagem , Adulto , Idoso , Traumatismos Craniocerebrais/diagnóstico por imagem , Traumatismos Craniocerebrais/etiologia , Serviço Hospitalar de Emergência , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Anamnese , Pessoa de Meia-Idade , Neuroimagem/métodos , Exame Neurológico , Estudos Retrospectivos , Fatores de Risco , Síncope/complicações , Tomografia Computadorizada por Raios X
12.
J Virol ; 93(2)2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30355683

RESUMO

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.


Assuntos
Ácidos e Sais Biliares/metabolismo , Antígenos de Grupos Sanguíneos/metabolismo , Proteínas do Capsídeo/metabolismo , Capsídeo/química , Sítios de Ligação , Capsídeo/metabolismo , Proteínas do Capsídeo/química , Cristalografia por Raios X , Humanos , Modelos Moleculares , Norovirus , Ligação Proteica , Conformação Proteica , Estabilidade Proteica
14.
Biomacromolecules ; 19(9): 3714-3724, 2018 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-30071731

RESUMO

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.


Assuntos
Antivirais/síntese química , Proteínas do Capsídeo/metabolismo , Fucose/química , Norovirus/efeitos dos fármacos , Antivirais/farmacologia , Proteínas do Capsídeo/química , Ligantes , Simulação de Acoplamento Molecular , Ligação Proteica
15.
Turk J Emerg Med ; 18(2): 71-74, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29922734

RESUMO

OBJECTIVE: Non-urgent patients are one of the important causes of emergency department (ED) overcrowding. In this study, it is aimed to identify the characteristics of these patients and the reasons why they prefer the ED. METHOD: This study was conducted during regular office hours. The characteristics of non-urgent patients, their complaints, the frequency of visits to family physicians (FPs), the frequency of using the Central Hospital Appointment System (CHAS) and reasons for preferring the ED were questioned by a questionnaire. RESULTS: This study was conducted on 624 patients. Among them, 326 (52.2%) were male. The mean age was 38.4 years (SD: 14.4). It was identified that 80.3% of the patients had no chronic disease and that 97.4% had health insurance. The most common complaints at presentation were musculoskeletal system pain (25.2%) and upper respiratory tract infections symptoms (19.7%). It was identified that 28.7% of the patients did not prefer to visit their FPs and that 48.6% did not use the CHAS. The reasons of preferring ED were as follows: rapid physical examination (36.4%), not being able to book an earlier appointment at alternative health facilities (30.9%), being close to the facility (12.8%) and being at the hospital for a different reason (12.3%). Among the patients, 20.2% did not express any particular reason. CONCLUSIONS: Non-urgent patients who admitted to the ED are mostly middle-aged patients with no chronic disease. They usually visit the ED for preventable reasons. The use of alternative health facilities and CHAS should be encouraged.

16.
J Virol ; 92(11)2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29563286

RESUMO

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.


Assuntos
Proteínas do Capsídeo/metabolismo , Norovirus/metabolismo , Receptores Imunológicos/metabolismo , Receptores Virais/metabolismo , Ligação Viral , Sequência de Aminoácidos , Animais , Sítios de Ligação , Infecções por Caliciviridae/virologia , Linhagem Celular Transformada , Cristalografia por Raios X , Gastroenterite/virologia , Especificidade de Hospedeiro/fisiologia , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Domínios Proteicos , Células RAW 264.7 , Alinhamento de Sequência
17.
Turk J Emerg Med ; 17(3): 95-98, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28971156

RESUMO

OBJECTIVES: Tetanus is a vaccine-preventable infectious disease. It is caused by the bacterium Clostridium tetani. The aim of this study was to investigate tetanus immunity among adult trauma patients. MATERIAL AND METHODS: This study was performed with 267 trauma patients who were admitted to the emergency department of Tepecik Training and Research Hospital in Izmir City, Turkey over a six month period. After obtaining a written informed consent from each patient, a questionnaire concerning demographic information and tetanus vaccination history was filled in by the physician. Patients' blood samples (4-5 cc) were drawn into a test tube while creating an intravenous (IV) access prior to making any attempt for therapy. And the tetanus antibody level (IgG) was measured using the enzyme-linked immunosorbent assay method. Tetanus antibody levels ≥0.1 IU/mL were considered protective. RESULTS: Among 267 patients, 192 and 75 of the cases (71.9% and 28.1%) were male and female, respectively. The median age of the patients was 39 (IQRs = 28-52). Seventy-five percent of the patients (n = 201) had protective immunity rates for tetanus. DISCUSSION AND CONCLUSION: In our study, which was conducted among adults, it was found that the protective ratio of tetanus immunity decreased with age with an additional, significant decline in elderly patients.

18.
Am J Emerg Med ; 35(10): 1408-1413, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28431869

RESUMO

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.


Assuntos
Nervo Óptico/diagnóstico por imagem , Hemorragia Subaracnóidea/diagnóstico , Tomografia Computadorizada por Raios X , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Serviço Hospitalar de Emergência , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Curva ROC , Reprodutibilidade dos Testes , Adulto Jovem
19.
Turk J Emerg Med ; 17(4): 128-131, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29464214

RESUMO

OBJECTIVES: Diagnosis of subarachnoid hemorrhage (SAH) in patients presenting with headache is challenging and there has been any biomarker studied for excluding of SAH in those patients. We aim to determine the sensitivity of leukocytosis or left shift to exclude the diagnosis of SAH in ED patients presenting with headache. METHOD: Adult patients with headache who received a computed tomography (CT) with the diagnosis of SAH and had a complete blood count (CBC) represent the case group, headache patients with normal CT and had a CBC represent the control group. The white blood cell (WBC) count and percentage of polymorphonuclear cells (PMNs%) taken during admission and within the first 6 and 12 h of admission were recorded. RESULTS: A hundred ninety seven patients with SAH and 197 patients without SAH were enrolled in to study. Sensitivity, specificity, NPV and PPV of leukocytosis or increase in PMNs% (left shift) in the diagnosis of SAH was 89.8% (84.5-93.5, 95% CI), 46.7% (39.6-53.9, 95% CI), 82.1% (73.5-88.4, 95% CI) and 62.8% (56.8-68.4, 95% CI) respectively on initial emergency department (ED) admission. CONCLUSION: CBC should be considered as a noninvasive test for the exclusion of SAH in ED patients with 6 h observation.

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