Stop the biting: targeting a mosquito's sense of smell.

Mosquitoes are a great threat to human health. Fortunately, they have a weakness: they utilize their sense of smell to target a human host. Recent studies examine the effectiveness of protecting humans from attack by ablating or odorant targeting mosquito olfactory receptors. The results are both promising and alarming.

The Q system: a repressible binary system for transgene expression, lineage tracing, and mosaic analysis.

We describe a new repressible binary expression system based on the regulatory genes from the Neurospora qa gene cluster. This "Q system" offers attractive features for transgene expression in Drosophila and mammalian cells: low basal expression in the absence of the transcriptional activator QF, high QF-induced expression, and QF repression by its repressor QS. Additionally, feeding flies quinic acid can relieve QS repression. The Q system offers many applications, including (1) intersectional "logic gates" with the GAL4 system for manipulating transgene expression patterns, (2) GAL4-independent MARCM analysis, and (3) coupled MARCM analysis to independently visualize and genetically manipulate siblings from any cell division. We demonstrate the utility of the Q system in determining cell division patterns of a neuronal lineage and gene function in cell growth and proliferation, and in dissecting neurons responsible for olfactory attraction. The Q system can be expanded to other uses in Drosophila and to any organism conducive to transgenesis.

Pixel walking along the boreal forest-Arctic tundra ecotone: Large scale ground-truthing of satellite-derived greenness (NDVI).

In this Technical Advance, we describe a novel method to improve ecological interpretation of remotely sensed vegetation greenness measurements that involved sampling 24,395 Landsat pixels (30 m) across 639 km of Alaska's central Brooks Range. The method goes well beyond the spatial scale of traditional plot-based sampling and thereby more thoroughly relates ground-based observations to satellite measurements. Our example dataset illustrates that, along the boreal-Arctic boundary, vegetation with the greatest Landsat Normalized Difference Vegetation Index (NDVI) is taller than 1 m, woody, and deciduous; whereas vegetation with lower NDVI tends to be shorter, evergreen, or non-woody. The field methods and associated analyses advance efforts to inform satellite data with ground-based vegetation observations using field samples collected at spatial scales that closely match the resolution of remotely sensed imagery.

Vascular access teams: a global outlook on challenges, benefits, opportunities, and future perspectives.

BACKGROUND: Specialized vascular access training for medical professionals organized into vascular access teams (VATs) was shown to improve patient outcomes, clinical efficiency, and cost savings. Professional perspectives on VAT benefits, organization, challenges, and opportunities on a global scale remain inadequately explored. Using detailed perspectives, in this study, we explored the global VAT landscape, including challenges faced, clinical and clinico-economic impacts of VATs, with emphasis on underresearched facets of VAT initiation, data dissemination, and metrics or benchmarks for VAT success. METHODS: Semistructured in-depth interviews of 14 VAT professionals from 9 countries and 5 continents were used to elicit qualitative and quantitative information. RESULTS: Catheter insertions (100%) and training (86%) were the most performed VAT functions. Based on a 1-7 scale evaluating observed impacts of VATs, patient satisfaction (6.5) and institutional costs (6.2) were ranked the highest. VAT co-initiatives, advanced technology utilization (6.6), and ongoing member training (6.3) distinctly impacted VAT endeavors. Most institutions (64%) did not have routine mechanisms for recording VAT-related data; however, all participants (100%) stated the importance of sharing data to demonstrate VAT impacts. Time constraints (57%) emerged as one of the major deterrents to data collection or dissemination. The majority (64%) experienced an increased demand or workload for VAT services during the COVID-19 pandemic. CONCLUSIONS: Despite the global variances in VATs and gaps in VAT-related data, all participants unanimously endorsed the benefits of VAT programs. Evaluating the impact of VATs, disseminating VAT-related data, and forging specialized institutional partnerships for data sharing and training are potential strategies to tackle the hurdles surrounding VAT formation and sustenance.

Olfaction in Anopheles mosquitoes.

As vectors of disease, mosquitoes are a global threat to human health. The Anopheles mosquito is the deadliest mosquito species as the insect vector of the malaria-causing parasite, which kills hundreds of thousands every year. These mosquitoes are reliant on their sense of smell (olfaction) to guide most of their behaviors, and a better understanding of Anopheles olfaction identifies opportunities for reducing the spread of malaria. This review takes a detailed look at Anopheles olfaction. We explore a range of topics from chemosensory receptors, olfactory neurons, and sensory appendages to behaviors guided by olfaction (including host-seeking, foraging, oviposition, and mating), to vector management strategies that target mosquito olfaction. We identify many research areas that remain to be addressed.

Dual-Energy CT to Differentiate Small Foci of Intracranial Hemorrhage from Calcium.

Background Diagnostic uncertainty in CT of possible intracranial hemorrhage requires short-interval follow-up imaging, resulting in reduced efficiency of care and higher costs. Purpose To quantify the diagnostic performance of dual-energy CT versus simulated single-energy CT in the differentiation of small foci of intracranial hemorrhage from calcium. Materials and Methods Images from consecutive unenhanced dual-energy CT of the head in patients from a single emergency department obtained from December 2014 to April 2016 were reviewed retrospectively for hyperattenuating intracranial foci. Ground truth was established from reference standard comparison CT or MRI. Foci were divided into development and test sets. Development set foci regions of interest were used to derive candidate CT attenuation thresholds for virtual noncalcium (VNCa) and calcium images. Test set foci were used for threshold validation, and diagnostic performance and confidence were evaluated for two readers blinded to final diagnosis. Statistical comparisons were made with exact binomial tests or repeated-measures analysis of variance. Results The study included 137 patients (65 years ± 17; 70 men) with 146 foci. Foci were divided into a development set (n = 105) and a test set (n = 41). Quantitative analysis of the development set produced candidate thresholds of 44 HU for VNCa images and 7 HU for calcium-only images, yielding diagnostic accuracies for the test set of 88% (36 of 41 foci; 95% confidence interval [CI]: 78%, 98%) and 95% (39 of 41 foci; 95% CI: 88%, 100%), respectively. Dual-energy CT improved reader accuracy from 90% (reader 1, 37 of 41 foci; 95% CI: 81%, 99%) and 93% (reader 2, 38 of 41 foci; 95% CI: 85%, 100%) to 100% (both readers, 41 of 41 foci; 95% CI: 100%, 100%). Diagnostic confidence (classifications rated as "certain") increased from 71% (29 of 41 foci; 95% CI: 57%, 85%) to 90% (37 of 41 foci; 95% CI: 81%, 99%) for reader 1 (P = .019) and from 46% (19 of 41 foci; 95% CI: 31%, 62%) to 85% (35 of 41 foci; 95% CI: 75%, 96%) for reader 2 (P = .0001). Conclusion Dual-energy CT showed high diagnostic performance in the differentiation of small foci of intracranial hemorrhage from calcium and improved diagnostic accuracy and confidence in the initial evaluation of suspected hemorrhage. © RSNA, 2019 See also the editorial by Kotsenas in this issue.

Insect repellents mediate species-specific olfactory behaviours in mosquitoes.

BACKGROUND: The species-specific mode of action for DEET and many other mosquito repellents is often unclear. Confusion may arise for many reasons. First, the response of a single mosquito species is often used to represent all mosquito species. Second, behavioural studies usually test the effect of repellents on mosquito attraction towards human odorants, rather than their direct repulsive effect on mosquitoes. Third, the mosquito sensory neuron responses towards repellents are often not directly examined. METHODS: A close proximity response assay was used to test the direct repulsive effect of six mosquito repellents on Anopheles coluzzii, Aedes aegypti and Culex quinquefasciatus mosquitoes. Additionally, the behavioural assay and calcium imaging recordings of antennae were used to test the response of An. coluzzii mosquitoes towards two human odorants (1-octen-3-ol and benzaldehyde) at different concentrations, and mixtures of the repellents lemongrass oil and p-menthane-3,8-diol (PMD) with DEET. RESULTS: Anopheles coluzzii mosquitoes were repelled by lemongrass oil and PMD, while Ae. aegypti and Cx. quinquefasciatus mosquitoes were repelled by lemongrass oil, PMD, eugenol, and DEET. In addition, high concentrations of 1-octen-3-ol and benzaldehyde were repellent, and activated more olfactory receptor neurons on the An. coluzzii antennae than lower concentrations. Finally, changes in olfactory responses to repellent mixtures reflected changes in repulsive behaviours. CONCLUSIONS: The findings described here suggest that different species of mosquitoes have different behavioural responses to repellents. The data further suggest that high-odour concentrations may recruit repellent-sensing neurons, or generally excite many olfactory neurons, yielding repellent behavioural responses. Finally, DEET can decrease the neuronal and behavioural response of An. coluzzii mosquitoes towards PMD but not towards lemongrass oil. Overall, these studies can help inform mosquito repellent choice by species, guide decisions on effective repellent blends, and could ultimately identify the olfactory neurons and receptors in mosquitoes that mediate repellency.

Multidetector CT of Laryngeal Injuries: Principles of Injury Recognition.

Blunt laryngeal trauma is associated with high morbidity and mortality. However, owing to their relatively rare occurrence, laryngeal injuries may be missed or underdiagnosed. Even subtle abnormalities at multidetector CT may correspond to significant functional abnormalities. It is important to understand normal CT laryngeal anatomy and develop a systematic review of the cervical soft tissues and laryngeal skeleton in patients who undergo screening CT cervical spine or other neck examinations in the setting of trauma, such as CT angiography. Multidetector CT findings of the normal larynx are reviewed, and blunt laryngeal injuries including soft-tissue edema, hematoma, mucosal lacerations, cartilage fracture, cricoarytenoid dislocation, and vocal fold paralysis are presented. The radiologist plays an important role in diagnosis and may be the first to identify laryngeal injuries that are not evident at physical examination. This article reviews normal laryngeal anatomy, presents various blunt laryngeal injuries at multidetector CT with case examples, discusses the role of multidetector CT in acute management, and describes pitfalls of diagnosis. ©RSNA, 2019.

CT for Treatment Selection in Acute Ischemic Stroke: A Code Stroke Primer.

CT is the primary imaging modality used for selecting appropriate treatment in patients with acute stroke. Awareness of the typical findings, pearls, and pitfalls of CT image interpretation is therefore critical for radiologists, stroke neurologists, and emergency department providers to make accurate and timely decisions regarding both (a) immediate treatment with intravenous tissue plasminogen activator up to 4.5 hours after a stroke at primary stroke centers and (b) transfer of patients with large-vessel occlusion (LVO) at CT angiography to comprehensive stroke centers for endovascular thrombectomy (EVT) up to 24 hours after a stroke. Since the DAWN and DEFUSE 3 trials demonstrated the efficacy of EVT up to 24 hours after last seen well, CT angiography has become the operational standard for rapid accurate identification of intracranial LVO. A systematic approach to CT angiographic image interpretation is necessary and useful for rapid triage, and understanding common stroke syndromes can help speed vessel evaluation. Moreover, when diffusion-weighted MRI is unavailable, multiphase CT angiography of collateral vessels and source-image assessment or perfusion CT can be used to help estimate core infarct volume. Both have the potential to allow distinction of patients likely to benefit from EVT from those unlikely to benefit. This article reviews CT-based workup of ischemic stroke for making tPA and EVT treatment decisions and focuses on practical skills, interpretation challenges, mimics, and pitfalls.©RSNA, 2019.

Blunt traumatic vascular injuries of the head and neck in the ED.

Cerebrovascular injury is increasingly identified in patients presenting after blunt trauma due to the implementation of screening criteria and advances in noninvasive angiographic imaging by CT. The variable latent time before onset of secondary stroke presents a window of opportunity for prevention, reinforcing the importance of detection of asymptomatic patients via screening. Furthermore, the high morbidity and mortality associated with secondary stroke makes it imperative that radiologists recognize these challenging injuries. This article reviews the epidemiology of and the various proposed screening criteria for blunt cerebrovascular injury. The imaging findings of extra- and intracranial vascular injuries, including arterial and venous trauma, are reviewed along with the grading system. Conservative management with anticoagulation has gained favor over the years with intervention restricted to high-grade injuries such as transection and hemodynamically significant arteriovenous fistula. Many of these injuries also evolve over time, with or without anticoagulation, necessitating imaging follow-up.

Spectrum of diagnostic errors in cervical spine trauma imaging and their clinical significance.

PURPOSE: To describe and categorize diagnostic errors in cervical spine CT (CsCT) interpretation performed for trauma and to assess their clinical significance. METHODS: All CsCTs performed for trauma with diagnostic errors that came to our attention based on clinical or imaging follow-up or quality assurance peer review from 2004 to 2017 were included. The number of CsCTs performed at our institution during the same time interval was calculated. Errors were categorized as spinal/extraspinal, involving osseous/soft tissue structures, by anatomical site and level. Images were reviewed by a radiologist and two spine surgeons. For each error, the need for surgery, immobilization, CT angiogram of the neck, and MRI was assessed; if any of these were needed, the error was considered clinically significant. RESULTS: Of an approximate total 59,000 CsCTs, 56 reports containing diagnostic errors were included. Twelve were extraspinal, and 44 were spinal (26 fractures, 15 intervertebral disc protrusions, two subluxations, one lytic bone lesion). The most common sites of spinal fractures were vertebral body (n = 10) and transverse process (n = 8); the most common levels were C5 (n = 8) and C7 (n = 6). All (n = 26) fractures and two atlantooccipital subluxations were considered clinically significant, including three patients who would have required urgent surgical stabilization (two subluxations and one facet fracture). Two transverse processes fractures did not alter the need for surgical intervention/surgical approach, immobilization, or MRI. CONCLUSIONS: In our study, 66% of spinal diagnostic errors on CsCT were considered clinically significant, potentially altering clinical management. Transverse process and vertebral body fractures were commonly missed.

Correction to: Spectrum of diagnostic errors in cervical spine trauma imaging and their clinical significance.

The published version of this article unfortunately contained a mistake. Author given and family name Alessandrino Francesco was incorrectly interchanged. The correct presentation is given above. The original article has been corrected.

Neurosurgical complications: what the radiologist needs to know.

Visits to the emergency department by patients who have recently undergone neurosurgery are a common occurrence, and these patients frequently receive emergent cross-sectional head imaging in order to evaluate for complications. Different neurosurgical approaches may have typical postoperative imaging findings that can be confused with pathology. Furthermore, particular abnormal postoperative imaging findings may signal an evolving complication. It is essential for the radiologist to understand common neurosurgical procedures and their potential complications in order to provide proper diagnostic evaluation of the postoperative neurosurgical patient. The purpose of this review is to assist radiologists in the evaluation of the postoperative neurosurgical patient and educate them on associated complications. Familiarity with common neurosurgical techniques and postoperative complications will help radiologists make the correct diagnosis, communicate effectively with the neurosurgeon, and expedite patient care.

Improved and expanded Q-system reagents for genetic manipulations.

The Q system is a repressible binary expression system for transgenic manipulations in living organisms. Through protein engineering and in vivo functional tests, we report here variants of the Q-system transcriptional activator, including QF2, for driving strong and ubiquitous expression in all Drosophila tissues. Our QF2, Gal4QF and LexAQF chimeric transcriptional activators substantially enrich the toolkit available for transgenic regulation in Drosophila melanogaster.

Loss of FAS/FASL signalling does not reduce apoptosis in Sharpin null mice.

Mice with mutations in SHANK-associated RH domain interactor (Sharpin) develop a hypereosinophilic auto-inflammatory disease known as chronic proliferative dermatitis. Affected mice have increased apoptosis in the keratinocytes of the skin, oesophagus and forestomach driven by extrinsic TNF receptor-mediated apoptotic signalling pathways. FAS receptor signalling is an extrinsic apoptotic signalling mechanism frequently involved in inflammatory skin diseases. Compound mutations in Sharpin and Fas or Fasl were created to determine whether these death domain proteins influenced the cutaneous phenotype in Sharpin null mice. Both Sharpin/Fas and Sharpin/Fasl compound mutant mice developed an auto-inflammatory phenotype similar to that seen in Sharpin null mice, indicating that initiation of apoptosis by FAS signalling is likely not involved in the pathogenesis of this disease.

Skin fragility in the wild-derived, inbred mouse strain Mus pahari/EiJ.

Mus pahari is a wild-derived, inbred mouse strain. M. pahari colony managers observed fragility of this strain's skin resulting in separation of tail skin from the mouse if handled incorrectly. Tail skin tension testing of M. pahari resulted in significantly lowered force threshold for caudal skin rupture and loss in comparison to closely related inbred mouse species and subspecies and even more than a model for junctional epidermolysis bullosa. Histologically, the tail skin separated at the subdermal level with the dermis firmly attached to the epidermis, excluding the epidermolysis bullosa complex of diseases. The dermal collagen bundles were abnormally thickened and branched. Elastin fiber deposition was focally altered in the dermis adjacent to the hair follicle. Collagens present in the skin could not be differentiated between the species in protein gels following digestion with pepsin. Together these data suggest that M. pahari have altered extracellular matrix development resulting in separation of the skin below the level of the dermis with moderate force similar to the African spiny mouse (Acomys spp.).

Core curriculum illustration: invasive fungal sinusitis.

This is the 27th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.erad.org/?page=CCIP_TOC .

Perimesencephalic Hemorrhage: Yield of Single versus Multiple DSA Examinations-A Single-Center Study and Meta-Analysis.

Purpose To quantify the rate of detection of aneurysms at follow-up digital subtraction angiography (DSA) after initial DSA with results negative for aneurysms in subjects with perimesencephalic (PM) nonaneurysmal subarachnoid hemorrhage. Materials and Methods This single-center retrospective study and meta-analysis was approved by the institutional review board. At a single institution from 2000 to 2013, 252 consecutive patients with subarachnoid hemorrhage at computed tomography (CT) and two DSA examinations negative for aneurysm within 10 days were evaluated for inclusion in the study, and 131 met CT criteria for PM nonaneurysmal subarachnoid hemorrhage (53 women; mean age, 53 years [range, 33-88 years]). DS angiographic reports were reviewed for causative abnormalities. Three reviewers searched MEDLINE and electronic databases for studies that reported detection of aneurysm in subjects with PM hemorrhage who had undergone multiple DSA examinations. Main inclusion criteria were PM hemorrhage at CT per van Gijn classification, head CT performed within 72 hours of symptom onset, initial DS angiographic results negative for aneurysm, and two DSA examinations within 10 days. Studies with fewer than 25 subjects were excluded. Methodology was assessed by using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The summary rate of aneurysm detection for subsequent DSA was calculated by using a fixed-effects model. Results Six studies with 298 subjects and a single-institution study with 131 subjects were included. No aneurysms were seen at follow-up DSA in the single-center study (0.0%). Three aneurysms were detected at follow-up DSA in three of six studies from the literature (one of 29 [3.4%], one of 65 [1.5%], and one of 34 [2.9%] patients). Two occurred in cases that likely preceded the use of the current DSA technique. The summary aneurysm detection rate at subsequent DSA was 1.6% (95% confidence interval: 0.7%, 3.8%; range of individual study detection rate: 0.0%-3.4%). Conclusion In patients with PM nonaneurysmal subarachnoid hemorrhage and initial DSA negative for aneurysms, the yield of follow-up DSA for detection of causative aneurysms is very low. © RSNA, 2016 Online supplemental material is available for this article.

Dual-Energy CT in Emergency Neuroimaging: Added Value and Novel Applications.

Dual-energy computed tomography (CT) is a powerful diagnostic tool that is becoming more widely clinically available. Dual-energy CT has the potential to aid in the detection or add diagnostic confidence in the evaluation of a variety of emergent neurologic conditions with use of postprocessing techniques that allow one to take advantage of the different x-ray energy-dependent absorption behaviors of different materials. Differentiating iodine from hemorrhage may help in delineating CT angiographic spot signs, which are small foci of intracranial hemorrhage seen on CT angiograms in cases of acute hemorrhage. Bone subtraction can be used to effectively exclude osseous structures surrounding enhancing vessels at imaging for improved vessel visualization and to create images that are similar in appearance to three-dimensional magnetic resonance imaging vessel reconstructions. Bone subtraction may also be helpful for improving the conspicuity of small extra-axial fluid collections and extra-axial masses. Material characterization can be helpful for clarifying whether small foci of intermediate attenuation represent hemorrhage, calcification, or a foreign material, and it may also be useful for quantifying the amount of hemorrhage or iodine in preexisting or incidentally detected lesions. Virtual monochromatic imaging also can be used to problem solve in challenging cases. ©RSNA, 2016.

Farnesol-detecting olfactory neurons in Drosophila.

We set out to deorphanize a subset of putative Drosophila odorant receptors expressed in trichoid sensilla using a transgenic in vivo misexpression approach. We identified farnesol as a potent and specific activator for the orphan odorant receptor Or83c. Farnesol is an intermediate in juvenile hormone biosynthesis, but is also produced by ripe citrus fruit peels. Here, we show that farnesol stimulates robust activation of Or83c-expressing olfactory neurons, even at high dilutions. The CD36 homolog Snmp1 is required for normal farnesol response kinetics. The neurons expressing Or83c are found in a subset of poorly characterized intermediate sensilla. We show that these neurons mediate attraction behavior to low concentrations of farnesol and that Or83c receptor mutants are defective for this behavior. Or83c neurons innervate the DC3 glomerulus in the antennal lobe and projection neurons relaying information from this glomerulus to higher brain centers target a region of the lateral horn previously implicated in pheromone perception. Our findings identify a sensitive, narrowly tuned receptor that mediates attraction behavior to farnesol and demonstrates an effective approach to deorphanizing odorant receptors expressed in neurons located in intermediate and trichoid sensilla that may not function in the classical "empty basiconic neuron" system.