Molecular characterization of the severe acute respiratory syndrome coronavirus has revealed genetic diversity among isolates. The spike (S) glycoprotein, the major target for vaccine and immune ...therapy, shows up to 17 substitutions in its 1,255-aa sequence; however, the biologic significance of these changes is unknown. Here, the functional effects of S mutations have been determined by analyzing their affinity for a viral receptor, human angiotensin-converting enzyme 2 (hACE-2), and their sensitivity to Ab neutralization with viral pseudotypes. Although minor differences among eight strains transmitted during human outbreaks in early 2003 were found, substantial functional changes were detected in S derived from a case in late 2003 from Guangdong province S(GD03T0013) and from two palm civets, S(SZ3) and S(SZ16). S(GD03T0013) depended less on the hACE-2 receptor and was markedly resistant to Ab inhibition. Unexpectedly, Abs that neutralized most human S glycoproteins enhanced entry mediated by the civet virus S glycoproteins. The mechanism of enhancement involved the interaction of Abs with conformational epitopes in the hACE-2-binding domain. Finally, improved immunogens and mAbs that minimize this complication have been defined. These data show that the entry of severe acute respiratory syndrome coronaviruses can be enhanced by Abs, and they underscore the need to address the evolving diversity of this newly emerged virus for vaccines and immune therapies.
Ultrasound (US) guidance for central venous catheter (CVC) placement results in improved success and overall safety, but is a new skill for pediatric emergency medicine (PEM) physicians. No study to ...date has used simulation-based learning to evaluate the ability of PEM providers to perform US-guided CVC placement.Our objective was to assess the competency of physicians in a rarely performed procedure, US-guided CVC placement, before and after an educational intervention using simulation-based mastery learning.
We performed a prospective cohort study evaluating change in PEM physician competency in US-guided CVC placement before and after an educational intervention. Subjects participated in a curriculum composed of 3 sessions: an intervention session, a 2-month follow-up session, and a 12-month follow-up session. At each session, subjects were observed using US to guide CVC placement on a simulation model and technical skill was scored using a validated direct-observation checklist. Competency was defined as successfully completing 7 critical items on the checklist.
Of the 28 PEM physicians participating, competency improved from 32% at preintervention to 93% at 2-month follow-up (difference, 62%; 95% confidence interval, 36%-84%). At 12-month follow-up, competency remained high (85%; difference, 53%; 95% confidence interval, 32%-75%).
Physician competency in US-guided CVC placement improved with a simulation-based educational intervention, and the effect was maintained over time. This study may serve as a model for outcomes-based education and certification in rarely performed procedures in pediatrics.
Objectives
Intussusception is a pediatric medical emergency that can be difficult to diagnose. Radiology‐performed ultrasound is the diagnostic study of choice but may lead to delays due to lack of ...availability. Point‐of‐care ultrasound for intussusception (POCUS‐I) studies have shown excellent accuracy and reduced lengths of stay, but there are limited POCUS‐I training materials for pediatric emergency medicine (PEM) providers.
Methods
We performed a prospective cohort study assessing PEM physicians undergoing a primarily Web‐based POCUS‐I curriculum. We developed the POCUS‐I curriculum using Kern’s six‐step model. The curriculum included a Web‐based module and a brief, hands‐on practice that was developed with a board‐certified pediatric radiologist. POCUS‐I technical skill, knowledge, and confidence were determined by a direct observation checklist, multiple‐choice test, and a self‐reported Likert‐scale survey, respectively. We assessed participants immediately pre‐ and postcourse as well as 3 months later to assess for retention of skill, knowledge, and confidence.
Results
A total of 17 of 17 eligible PEM physicians at a single institution participated in the study. For the direct observation skills test, participants scored well after the course with a median (interquartile range IQR) score of 20 of 22 (20–21) and maintained high scores even after 3 months (20 20–21). On the written knowledge test, there was significant improvement from 57.4% (95% CI = 49.8 to 65.2) to 75.3% (95% CI = 68.1 to 81.6; p < 0.001) and this improvement was maintained at 3 months at 81.2% (95% CI = 74.5 to 86.8). Physicians also demonstrated improved confidence with POCUS‐I after exposure to the curriculum, with 5.9% reporting somewhat or very confident prior to the course to 76.5% both after the course and after 3 months (p < 0.001).
Conclusion
After a primarily Web‐based curriculum for POCUS‐I, PEM physicians performed well in technical skill in POCUS‐I and showed improvement in knowledge and confidence, all of which were maintained over 3 months.
A growing body of literature supports the use of ultrasound (US) to assist central venous catheter (CVC) placement, and in many settings, this has become the standard of care. However, this remains a ...relatively new and uncommonly performed procedure for pediatric emergency medicine physicians.
This study aims to describe the change over time in percentage of CVC procedures performed with US assistance per 10,000 patient visits in a pediatric emergency department.
We describe the development of an emergency US program in a pediatric emergency department and investigate how US use for CVC placement in internal jugular and femoral veins changed from July 2007, when US became available, until December 2011. Data related to CVC procedures were obtained from a procedure database maintained for quality assurance purposes.
The percentage of CVC procedures performed with US assistance increased significantly over time (P < 0.001).
The development of an emergency US program was associated with significantly increased physician use of US for CVC placement.
Bats are reservoirs of emerging viruses that are highly pathogenic to other mammals, including humans. Despite the diversity and abundance of bat viruses, to date they have not been shown to harbor ...exogenous retroviruses. Here we report the discovery and characterization of a group of koala retrovirus-related (KoRV-related) gammaretroviruses in Australian and Asian bats. These include the Hervey pteropid gammaretrovirus (HPG), identified in the scat of the Australian black flying fox (Pteropus alecto), which is the first reproduction-competent retrovirus found in bats. HPG is a close relative of KoRV and the gibbon ape leukemia virus (GALV), with virion morphology and Mn2+-dependent virion-associated reverse transcriptase activity typical of a gammaretrovirus. In vitro, HPG is capable of infecting bat and human cells, but not mouse cells, and displays a similar pattern of cell tropism as KoRV-A and GALV. Population studies reveal the presence of HPG and KoRV-related sequences in several locations across northeast Australia, as well as serologic evidence for HPG in multiple pteropid bat species, while phylogenetic analysis places these bat viruses as the basal group within the KoRV-related retroviruses. Taken together, these results reveal bats to be important reservoirs of exogenous KoRVrelated gammaretroviruses.
Autism spectrum disorder (ASD) affects up to 1 in 36 children in the United States. It is a heterogeneous neurodevelopmental disorder with life-long consequences. Patients with ASD and folate pathway ...abnormalities have demonstrated improved symptoms after treatment with leucovorin (folinic acid), a reduced form of folate. However, biomarkers for treatment response have not been well investigated and clinical trials are lacking. In this retrospective analysis, a cohort of prospectively collected data from 110 consecutive ASD clinic patients mean (SD) age: 10.5 (6.2) years; 74% male was examined. These patients all underwent testing for folate receptor alpha autoantibodies (FRAAs) and soluble folate binding proteins (sFBPs) biomarkers and were treated with leucovorin, if appropriate. Analyses examined whether these biomarkers could predict response to leucovorin treatment as well as the severity of ASD characteristics at baseline. The social responsiveness scale (SRS), a measure of core ASD symptoms, and the aberrant behavior checklist (ABC), a measure of disruptive behavior, were collected at each clinic visit. Those positive for sFBPs had more severe ASD symptoms, and higher binding FRAA titers were associated with greater ABC irritability. Treatment with leucovorin improved most SRS subscales with higher binding FRAA titers associated with greater response. Leucovorin treatment also improved ABC irritability. These results confirm and expand on previous studies, underscore the need for biomarkers to guide treatment of folate pathways in ASD, and suggest that leucovorin may be effective for children with ASD.
Xanthine oxidase (XO) catalyzes the catabolism of hypoxanthine to xanthine and xanthine to uric acid, generating oxidants as a byproduct. Importantly, XO activity is elevated in numerous hemolytic ...conditions including sickle cell disease (SCD); however, the role of XO in this context has not been elucidated. Whereas long-standing dogma suggests elevated levels of XO in the vascular compartment contribute to vascular pathology via increased oxidant production, herein, we demonstrate, for the first time, that XO has an unexpected protective role during hemolysis. Using an established hemolysis model, we found that intravascular hemin challenge (40 μmol/kg) resulted in a significant increase in hemolysis and an immense (20-fold) elevation in plasma XO activity in Townes sickle cell phenotype (SS) sickle mice compared to controls. Repeating the hemin challenge model in hepatocyte-specific XO knockout mice transplanted with SS bone marrow confirmed the liver as the source of enhanced circulating XO as these mice demonstrated 100% lethality compared to 40% survival in controls. In addition, studies in murine hepatocytes (AML12) revealed hemin mediates upregulation and release of XO to the medium in a toll like receptor 4 (TLR4)-dependent manner. Furthermore, we demonstrate that XO degrades oxyhemoglobin and releases free hemin and iron in a hydrogen peroxide-dependent manner. Additional biochemical studies revealed purified XO binds free hemin to diminish the potential for deleterious hemin-related redox reactions as well as prevents platelet aggregation. In the aggregate, data herein reveals that intravascular hemin challenge induces XO release by hepatocytes through hemin-TLR4 signaling, resulting in an immense elevation of circulating XO. This increased XO activity in the vascular compartment mediates protection from intravascular hemin crisis by binding and potentially degrading hemin at the apical surface of the endothelium where XO is known to be bound and sequestered by endothelial glycosaminoglycans (GAGs).
(Top) Canonical hemin scavenging pathway. (Bottom) Hemin overload releases XO via TLR-4 into the circulation leading to glycosaminoglycan binding on endothelium where XO generates H2O2 needed to “split” hemin and uric acid to chelate released Fe. Display omitted
•Intravascular heme crisis in mice is associated with a 20-fold elevation in circulating XO.•Pharmacologic inhibition or liver-specific knockout of XO results in diminished survival during heme crisis.•Free hemin induces a TLR4-dependent upregulation and export of XO in hepatocytes.•XO degrades oxyhemoglobin and free hemin in a H2O2-dependent manner.•Hemin-induced elevation of circulating XO may be a protective response.
Alcohol-related pancreatitis is associated with a disproportionately large number of hospitalisations among GI disorders. Despite its clinical importance, genetic susceptibility to alcoholic chronic ...pancreatitis (CP) is poorly characterised. To identify risk genes for alcoholic CP and to evaluate their relevance in non-alcoholic CP, we performed a genome-wide association study and functional characterisation of a new pancreatitis locus.
1959 European alcoholic CP patients and population-based controls from the KORA, LIFE and INCIPE studies (n=4708) as well as chronic alcoholics from the GESGA consortium (n=1332) were screened with Illumina technology. For replication, three European cohorts comprising 1650 patients with non-alcoholic CP and 6695 controls originating from the same countries were used.
We replicated previously reported risk loci
,
,
and
in alcoholic CP patients. We identified
(chymotrypsin B1 and B2) as a new risk locus with lead single-nucleotide polymorphism (SNP)
(OR 1.35, 95% CI 1.23 to 1.6). We found that a 16.6 kb inversion in the
locus was in linkage disequilibrium with the CP-associated SNPs and was best tagged by
. The association was replicated in three independent European non-alcoholic CP cohorts of 1650 patients and 6695 controls (OR 1.62, 95% CI 1.42 to 1.86). The inversion changes the expression ratio of the CTRB1 and CTRB2 isoforms and thereby affects protective trypsinogen degradation and ultimately pancreatitis risk.
An inversion in the
locus modifies risk for alcoholic and non-alcoholic CP indicating that common pathomechanisms are involved in these inflammatory disorders.
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