Signal transduction at GPCRs: Allosteric activation of the ERK MAPK by ß-arrestin.

ß-arrestins are multivalent adaptor proteins that bind active phosphorylated G protein-coupled receptors (GPCRs) to inhibit G protein signaling, mediate receptor internalization, and initiate alternative signaling events. ß-arrestins link agonist-stimulated GPCRs to downstream signaling partners, such as the c-Raf-MEK1-ERK1/2 cascade leading to ERK1/2 activation. ß-arrestins have been thought to transduce signals solely via passive scaffolding by facilitating the assembly of multiprotein signaling complexes. Recently, however, ß-arrestin 1 and 2 were shown to activate two downstream signaling effectors, c-Src and c-Raf, allosterically. Over the last two decades, ERK1/2 have been the most intensely studied signaling proteins scaffolded by ß-arrestins. Here, we demonstrate that ß-arrestins play an active role in allosterically modulating ERK kinase activity in vitro and within intact cells. Specifically, we show that ß-arrestins and their GPCR-mediated active states allosterically enhance ERK2 autophosphorylation and phosphorylation of a downstream ERK2 substrate, and we elucidate the mechanism by which ß-arrestins do so. Furthermore, we find that allosteric stimulation of dually phosphorylated ERK2 by active-state ß-arrestin 2 is more robust than by active-state ß-arrestin 1, highlighting differential capacities of ß-arrestin isoforms to regulate effector signaling pathways downstream of GPCRs. In summary, our study provides strong evidence for a new paradigm in which ß-arrestins function as active "catalytic" scaffolds to allosterically unlock the enzymatic activity of signaling components downstream of GPCR activation.

Human complete NFAT1 deficiency causes a triad of joint contractures, osteochondromas, and B-cell malignancy.

The discovery of humans with monogenic disorders has a rich history of generating new insights into biology. Here we report the first human identified with complete deficiency of nuclear factor of activated T cells 1 (NFAT1). NFAT1, encoded by NFATC2, mediates calcium-calcineurin signals that drive cell activation, proliferation, and survival. The patient is homozygous for a damaging germline NFATC2 variant (c.2023_2026delTACC; p.Tyr675Thrfs∗18) and presented with joint contractures, osteochondromas, and recurrent B-cell lymphoma. Absence of NFAT1 protein in chondrocytes caused enrichment in prosurvival and inflammatory genes. Systematic single-cell-omic analyses in PBMCs revealed an environment that promotes lymphomagenesis with accumulation of naïve B cells (enriched for oncogenic signatures MYC and JAK1), exhausted CD4+ T cells, impaired T follicular helper cells, and aberrant CD8+ T cells. This work highlights the pleiotropic role of human NFAT1, will empower the diagnosis of additional patients with NFAT1 deficiency, and further defines the detrimental effects associated with long-term use of calcineurin inhibitors.

Differential sensitivities of photosynthetic processes and carbon loss mechanisms govern N-induced variation in net carbon assimilation rate for field-grown cotton.

Nitrogen (N) deficiency limits the net carbon assimilation rate (AN), but the relative N sensitivities of photosynthetic component processes and carbon loss mechanisms remain relatively unexplored for field-grown cotton. Therefore, the objective of the current study was to define the relative sensitivity of individual physiological processes driving N deficiency-induced declines in AN for field-grown cotton. Among the potential diffusional limitations evaluated, mesophyll conductance was the only parameter substantially reduced by N deficiency, but this did not affect CO2 availability in the chloroplast. A number of metabolic processes were negatively impacted by N deficiency, and these effects were more pronounced at lower leaf positions in the cotton canopy. Ribulose bisphosphate (RuBP) regeneration and carboxylation, AN, and gross photosynthesis were the most sensitive metabolic processes to N deficiency, whereas photosynthetic electron transport processes, electron flux to photorespiration, and dark respiration exhibited intermediate sensitivity to N deficiency. Among thylakoid-specific processes, the quantum yield of PSI end electron acceptor reduction was the most sensitive process to N deficiency. It was concluded that AN is primarily limited by Rubisco carboxylation and RuBP regeneration under N deficiency in field-grown cotton, and the differential N sensitivities of the photosynthetic process and carbon loss mechanisms contributed significantly to photosynthetic declines.

Enhanced Transport of TiO2 in Unsaturated Sand and Soil after Release from Biodegradable Plastic during Composting.

Biodegradable plastics can reach full degradation when disposed of appropriately and thus alleviate plastic pollution caused by conventional plastics. However, additives can be released into the environment during degradation and the fate of these additives can be affected by the degradation process. Here, we characterized TiO2 particles released from a biodegradable plastic mulch during composting and studied the transport of the mulch-released TiO2 particles in inert sand and agricultural soil columns under unsaturated flow conditions. TiO2 particles (238 nm major axis and 154 nm minor axis) were released from the biodegradable plastic mulch in both single-particle and cluster forms. The mulch-released TiO2 particles were fully retained in unsaturated soil columns due to attachment onto the solid-water interface and straining. However, in unsaturated sand columns, the mulch-released TiO2 particles were highly mobile. A comparison with the pristine TiO2 revealed that the mobility of the mulch-released TiO2 particles was enhanced by humic acid present in the compost residues, which blocked attachment sites and imposed steric repulsion. This study demonstrates that TiO2 particles can be released during composting of biodegradable plastics and the transport potential of the plastic-released TiO2 particles in the terrestrial environment can be enhanced by compost residues.

Inborn errors of immunity manifesting as atopic disorders.

Inborn errors of immunity are traditionally best known for enhancing susceptibility to infections. However, allergic inflammation, among other types of immune dysregulation, occurs frequently in patients with inborn errors of immunity. As such, the term primary atopic disorders (PADs) was recently coined to describe the group of heritable monogenic allergic disorders. It is becoming increasingly important for clinicians to recognize that allergic diseases such as food allergy, atopic dermatitis, and allergic asthma are expressions of misdirected immunity, and in patients who present with severe, early-onset, or coexisting allergic conditions, these can be indications of an underlying PAD. Identifying monogenic allergic disease through next-generation sequencing can dramatically improve outcomes by allowing the use of precision-based therapy targeting the patient's underlying molecular defect. It is therefore imperative that clinicians recognize PADs to be able to provide informed therapeutic options and improve patient outcomes. Here, we summarize the clinical features commonly seen with each of the currently known PADs, identify clinical warning signs that warrant assessment for PADs, and lastly, discuss the benefits of timely diagnosis and management of these conditions.

Mechanistic understanding of the combined immunodeficiency in complete human CARD11 deficiency.

BACKGROUND: Germline pathogenic variants impairing the caspase recruitment domain family member 11 (CARD11)-B cell chronic lymphocytic leukemia/lymphoma 10 (BCL10)-MALT1 paracaspase (MALT1) (CBM) complex are associated with diverse human diseases including combined immunodeficiency (CID), atopy, and lymphoproliferation. However, the impact of CARD11 deficiency on human B-cell development, signaling, and function is incompletely understood. OBJECTIVES: This study sought to determine the cellular, immunological, and biochemical basis of disease for 2 unrelated patients who presented with profound CID associated with viral and fungal respiratory infections, interstitial lung disease, and severe colitis. METHODS: Patients underwent next-generation sequencing, immunophenotyping by flow cytometry, signaling assays by immunoblot, and transcriptome profiling by RNA-sequencing. RESULTS: Both patients carried identical novel pathogenic biallelic loss-of-function variants in CARD11 (c.2509C>T; p.Arg837∗) leading to undetectable protein expression. This variant prevented CBM complex formation, severely impairing the activation of nuclear factor-κB, c-Jun N-terminal kinase, and MALT1 paracaspase activity in B and T cells. This functional defect resulted in a developmental block in B cells at the naive and type 1 transitional B-cell stage and impaired circulating T follicular helper cell (cTFH) development, which was associated with impaired antibody responses and absent germinal center structures on lymph node histology. Transcriptomics indicated that CARD11-dependent signaling is essential for immune signaling pathways involved in the development of these cells. Both patients underwent hematopoietic stem cell transplantations, which led to functional normalization. CONCLUSIONS: Complete human CARD11 deficiency causes profound CID by impairing naive/type 1 B-cell and cTFH cell development and abolishing activation of MALT1 paracaspase, NF-κB, and JNK activity. Hematopoietic stem cell transplantation functionally restores impaired signaling pathways.

Development and Validation of Urological and Appearance Domains of the Post-Affirming Surgery Form and Function Individual Reporting Measure (AFFIRM) for Transwomen following Genital Surgery.

PURPOSE: As feminizing gender-affirming surgery becomes increasingly accessible, functional outcomes are increasingly relevant. We aimed to develop and validate the first patient-reported outcome questionnaire focusing on postoperative symptomatology and quality of life. MATERIAL AND METHODS: Questions were developed from interviews with postoperative transwomen followed by face validation from a multispecialty clinician group. The measure was co-administered with established relevant questionnaires for concurrent validity testing. Participants were asked to complete the questionnaire at baseline and at a 2-week retest interval. RESULTS: The AFFIRM questionnaire is a 33-item patient-reported outcome measure comprising Appearance, Urological and Gynecologic domains, each scored to create a composite AFFIRM score. A total of 102 women participated, with 60% completing the test-retest. The overall Cronbach's α for AFFIRM was 0.79, and domain α for AFFIRM-A, AFFIRM-U and AFFIRM-G was 0.85, 0.87 and 0.42, respectively. Test-retest demonstrated score reliability (z values -1.862 to -0.005, p >0.05) with intraclass coefficients demonstrating moderate to good absolute correlation (0.54 to 0.88). The AFFIRM-A and AFFIRM-U correlated well with the Genital Appearance Satisfaction Measure and Urinary Distress Inventory-6, respectively (ρ 0.556 and 0.618, p <0.001); 89% of participants confirmed congruence between their external genitalia and gender identity, 87.8% reported clitoral sensation and 75.6% expressed satisfaction with vaginal caliber. Reported symptoms included a misdirected urinary stream (68.9%), nocturia (51.3%), urinary frequency (29.7%) and vaginal pain (46.7%). CONCLUSIONS: Transwomen have diverse symptoms not captured by unstructured questions or cisgender questionnaires. The AFFIRM questionnaire is the first tool available to reliably evaluate outcomes following feminizing gender-affirming surgery.

Idiopathic splenomegaly in childhood and the spectrum of RAS-associated lymphoproliferative disease: a case report.

BACKGROUND: KRAS (KRAS proto-oncogene, GTPase; OMIM: 190,070) encodes one of three small guanosine triphosphatase proteins belonging to the RAS family. This group of proteins is responsible for cell proliferation, differentiation and inhibition of apoptosis. Gain-of-function variants in KRAS are commonly found in human cancers. Non-malignant somatic KRAS variants underlie a subset of RAS-associated autoimmune leukoproliferative disorders (RALD). RALD is characterized by splenomegaly, persistent monocytosis, hypergammaglobulinemia and cytopenia, but can also include autoimmune features and lymphadenopathy. In this report, we describe a non-malignant somatic variant in KRAS with prominent clinical features of massive splenomegaly, thrombocytopenia and lymphopenia. CASE PRESENTATION: A now-11-year-old girl presented in early childhood with easy bruising and bleeding, but had an otherwise unremarkable medical history. After consulting for the first time at 5 years of age, she was discovered to have massive splenomegaly. Clinical follow-up revealed thrombocytopenia, lymphopenia and increased polyclonal immunoglobulins and C-reactive protein. The patient had an unremarkable bone marrow biopsy, flow cytometry showed no indication of expanded double negative T-cells, while malignancy and storage disorders were also excluded. When the patient was 8 years old, whole exome sequencing performed on DNA derived from whole blood revealed a heterozygous gain-of-function variant in KRAS (NM_004985.5:c.37G > T; (p.G13C)). The variant was absent from DNA derived from a buccal swab and was thus determined to be somatic. CONCLUSIONS: This case of idiopathic splenomegaly in childhood due to a somatic variant in KRAS expands our understanding of the clinical spectrum of RAS-associated autoimmune leukoproliferative disorder and emphasizes the value of securing a molecular diagnosis in children with unusual early-onset presentations with a suspected monogenic origin.

Detection and localisation of primary prostate cancer using 68 gallium prostate-specific membrane antigen positron emission tomography/computed tomography compared with multiparametric magnetic resonance imaging and radical prostatectomy specimen pathology.

OBJECTIVE: To compare the accuracy of 68 gallium prostate-specific membrane antigen positron emission tomography/computed tomography (68 Ga-PSMA PET/CT) with multiparametric MRI (mpMRI) in detecting and localising primary prostate cancer when compared with radical prostatectomy (RP) specimen pathology. PATIENTS AND METHODS: Retrospective review of men who underwent 68 Ga-PSMA PET/CT and mpMRI for primary prostate cancer before RP across four centres between 2015 and 2018. Patients undergoing imaging for recurrent disease or before non-surgical treatment were excluded. We defined pathological index tumour as the lesion with highest International Society of Urological Pathology Grade Group (GG) on RP specimen pathology. Our primary outcomes were rates of accurate detection and localisation of RP specimen pathology index tumour using 68 Ga-PSMA PET/CT or mpMRI. We defined tumour detection as imaging lesion corresponding with RP specimen tumour on any imaging plane, and localisation as imaging lesion matching RP specimen index tumour in all sagittal, axial, and coronal planes. Secondary outcomes included localisation of clinically significant and transition zone (TZ) index tumours. We defined clinically significant disease as GG 3-5. We used descriptive statistics and the Mann-Whitney U-test to define and compare demographic and pathological characteristics between detected, missed and localised tumours using either imaging modality. We used the McNemar test to compare detection and localisation rates using 68 Ga-PSMA PET/CT and mpMRI. RESULTS: In all, 205 men were included in our analysis, including 133 with clinically significant disease. There was no significant difference between 68 Ga-PSMA PET/CT and mpMRI in the detection of any tumour (94% vs 95%, P > 0.9). There was also no significant difference between localisation of all index tumours (91% vs 89%, P = 0.47), clinically significant index tumours (96% vs 91%, P = 0.15) or TZ tumours (85% vs 80%, P > 0.9) using 68 Ga-PSMA PET/CT and mpMRI. Limitations include retrospective study design and non-central review of imaging and pathology. CONCLUSION: We found no significant difference in the detection or localisation of primary prostate cancer between 68 Ga-PSMA PET/CT and mpMRI. Further prospective studies are required to evaluate a combined PET/MRI model in minimising tumours missed by either modality.

Prevalence and intensity of persistent post-surgical pain following breast cancer surgery: a systematic review and meta-analysis of observational studies.

BACKGROUND: The prevalence and intensity of persistent post-surgical pain (PPSP) after breast cancer surgery are uncertain. We conducted a systematic review and meta-analysis to further elucidate this issue. METHODS: We searched MEDLINE, Embase, CINAHL, and PsycINFO, from inception to November 2018, for observational studies reporting persistent pain (≥3 months) after breast cancer surgery. We used random-effects meta-analysis and the Grading of Recommendations, Assessment, Development and Evaluations approach to rate quality of evidence. RESULTS: We included 187 observational studies with 297 612 breast cancer patients. The prevalence of PPSP ranged from 2% to 78%, median 37% (inter-quartile range: 22-48%); the pooled prevalence was 35% (95% confidence interval [CI]: 32-39%). The pooled pain intensity was 3.9 cm on a 10 cm visual analogue scale (95% CI: 3.6-4.2 cm). Moderate-quality evidence supported the subgroup effects of PPSP prevalence for localized pain vs any pain (29% vs 44%), moderate or greater vs any pain (26% vs 44%), clinician-assessed vs patient-reported pain (23% vs 36%), and whether patients underwent sentinel lymph node biopsy vs axillary lymph node dissection (26% vs 43%). The adjusted analysis found that the prevalence of patient-reported PPSP (any severity/location) was 46% (95% CI: 36-56%), and the prevalence of patient-reported moderate-to-severe PPSP at any location was 27% (95% CI: 10-43%). CONCLUSIONS: Moderate-quality evidence suggests that almost half of all women undergoing breast cancer surgery develop persistent post-surgical pain, and about one in four develop moderate-to-severe persistent post-surgical pain; the higher prevalence was associated with axillary lymph node dissection. Future studies should explore whether nerve sparing for axillary procedures reduces persistent post-surgical pain after breast cancer surgery.

Dietary nutrient balance shapes phenotypic traits of Drosophila melanogaster in interaction with gut microbiota.

The dietary nutrient composition can affect insects' phenotypes by modulating their physiology. Furthermore, diet can affect gut microbiota composition and abundance, with indirect consequences for the host. In this study, we reared Drosophila melanogaster on five different diets; three with balanced sugar:yeast ratio, but with increasing caloric content (2:2, 8:8, 16:16, in weight %), and two with imbalanced sugar:yeast ratio, either with low sugar and high yeast content (2:16) or vice-versa (16:2). In each of these diets, we compared flies with conventional vs. artificially altered gut microbiota with antibiotics that reduced the bacterial load. The antibiotic treatment also had the surprising effect of increasing the amount of live yeast associated with the flies. We characterized flies from these ten treatments (5 diets × 2 microbiota) in terms of development, body mass, food preference, body reserves, metabolic rate and a range of stress tolerance traits (heat, cold, starvation and desiccation tolerance). Diets, and to a lesser extent antibiotic treatment, affected development rate, weight, and cold tolerance of adult flies. Other traits such as energy reserves, metabolic rate, food preference, or starvation tolerance were affected by diet alone. When detected, the effect of antibiotic treatment was stronger in yeast-poor diets, suggesting that gut bacterial community might help to counterbalance nutritional deficiencies. These results show that changes in dietary factors lead to a global re-organization of fly's physiology and development while the manipulation of gut microorganisms had minor effects that were mainly seen in case of protein restriction.

Germline CBM-opathies: From immunodeficiency to atopy.

Caspase recruitment domain (CARD) protein-B cell CLL/lymphoma 10 (BCL10)-MALT1 paracaspase (MALT1) [CBM] complexes are critical signaling adaptors that facilitate immune and inflammatory responses downstream of both cell surface and intracellular receptors. Germline mutations that alter the function of members of this complex (termed CBM-opathies) cause a broad array of clinical phenotypes, ranging from profound combined immunodeficiency to B-cell lymphocytosis. With an increasing number of patients being described in recent years, the clinical spectrum of diseases associated with CBM-opathies is rapidly expanding and becoming unexpectedly heterogeneous. Here we review major discoveries that have shaped our understanding of CBM complex biology, and we provide an overview of the clinical presentation, diagnostic approach, and treatment options for those carrying germline mutations affecting CARD9, CARD11, CARD14, BCL10, and MALT1.

Evaluation of trauma resources in rural northern Alberta identifies opportunities for improvement.

Background: The care of rural trauma patients in northern Alberta can be extremely challenging because of the vast geographic area, the limited access to health care facilities and the lack of adequate resources to manage severe injuries. Identifying gaps in equipment and personnel in rural centres can provide opportunities for improving the care of injured patients in these environments. We conducted a survey based on Canadian Accreditation Council quality indicators to evaluate trauma infrastructure and human resources in rural centres across northern Alberta. Methods: A standardized survey was developed to assess the availability of trauma-specific equipment and personnel across the prehospital and emergency department (ED) settings. The survey was distributed to 50 peripheral hospitals biannually from January 2017 to September 2018. Two-tailed paired t tests were used to evaluate changes in survey responses; a p value of less than 0.05 was considered statistically significant. Results: The survey response rate was 100%. By the end of the study period, there were significant improvements in the number of providers (p = 0.04), nurses (p = 0.01) and dedicated trauma resuscitation bays (p = 0.04) in the ED for managing injured patients. There were also significant increases in the availability of equipment, including advanced airway management tools (p = 0.02), rapid infusion devices (p = 0.02) and warmers (p = 0.04). Access to x-ray equipment (p = 0.03) and computed tomography (CT) scanners (p = 0.04) as well as equipment to support telehealth and teleconferencing (p = 0.04) increased during the study period. Access to, and supply of, blood products also increased significantly (p = 0.02) during the study period. Conclusion: Our study demonstrates that the trauma resources of rural health care centres may be evaluated in a standardized fashion centres, and the results point to opportunities to remedy gaps in equipment and personnel. Our methods may be applied to any trauma network that serves geographically large areas with a sparse distribution of health care facilities, to provide critical information for the optimization of resources in rural trauma.

Contexte: Les soins aux patients victimes de traumatismes en région rurale dans le nord de l'Alberta peuvent être très difficiles en raison de la superficie de la région, de l'accès limité aux établissements de santé et du manque de ressources pour soigner adéquatement les blessures graves. En repérant les lacunes en équipement et en personnel dans les établissements en région rurale, on peut créer des occasions d'améliorer les soins aux patients blessés dans ces milieux. Nous avons mené un sondage fondé sur les indicateurs de qualité du Conseil d'accréditation canadien pour évaluer les infrastructures et les ressources humaines en traumatologie dans les établissements des régions rurales du nord de l'Alberta. Méthodes: Un sondage standardisé a été créé pour évaluer la disponibilité des équipements et des ressources humaines en traumatologie en contexte préhospitalier et aux services d'urgence. Le sondage a été distribué 2 fois par année à 50 hôpitaux entre janvier 2017 et septembre 2018. Des tests t appariés ayant une hypothèse non nulle ont été utilisés pour évaluer les changements dans les réponses au sondage; les résultats ayant une valeur p < 0,05 étaient considérés comme statistiquement significatifs. Résultats: Le taux de participation au sondage était de 100 %. À la fin de la période étudiée, il y avait une amélioration significative du nombre de fournisseurs (p = 0,04), de personnel infirmier (p = 0,01) et d'espaces de réanimation réservés à la traumatologie (p = 0,04) dans les services d'urgence. Il y avait aussi une augmentation significative de la disponibilité de l'équipement, notamment des outils de prise en charge avancée des voies respiratoires (p = 0,02), des appareils de perfusion rapide (p = 0,02) et d'armoires chauffantes (p = 0,04). Les équipements de radiographie (p = 0,03) et de tomographie par ordinateur (p = 0,04) ainsi que les équipements facilitant la télémédecine et les téléconférences (p = 0,04) sont devenus plus accessibles pendant la période étudiée. Les réserves de produits sanguins et l'accès à ces produits a aussi augmenté de manière significative (p = 0,02). Conclusion: Notre étude montre que les ressources en traumatologie dans les établissements de santé en région rurale peuvent être évaluées de manière standardisée, et les résultats indiquent qu'il y a des occasions de combler les lacunes en équipement et en personnel. Notres méthodes peuvent être reproduites dans tout réseau de traumatologie couvrant un grand territoire où les établissements de santé sont dispersés, pour fournir des données critiques sur l'organisation des ressources de traumatologie en région rurale.

"Immuno-flowFISH" for the Assessment of Cytogenetic Abnormalities in Chronic Lymphocytic Leukemia.

Imaging flow cytometry is emerging as a diagnostic tool for the assessment of leukemia. It has the functionality of standard flow cytometry and generates high-resolution digital images of each cell with quantifiable numerical data. We demonstrate the use of an automated high-throughput method for performing fluorescence in situ hybridization (FISH) on immunophenotyped whole cells in suspension and analyzed by imaging flow cytometry, a technique called "Immuno-flowFISH". The aim of this study was to demonstrate the application of immuno-flowFISH for the detection of chromosomal abnormalities in CLL, specifically trisomy 12 and del(17p). Mononuclear cells were isolated and immunophenotyped with fluorescently conjugated CD3, CD5, and CD19 monoclonal antibodies. Following fixation, cells were permeabilized, dsDNA denatured and hybridized with chromosome 12 or 17 enumeration (CEP 12 and CEP17) and 17p12 locus-specific FISH probes. Cells were analyzed on the Amnis ImageStream®X Mark II to assess the number and percent FISH-positive CLL cells and the ratio of FISH spot counts for CD5/CD19-positive CLL cells to CD3/CD5-positive T cells (FISH "mean spot ratio"). Deletion of 17p was detected in about 8% of cases to date, with del(17p) ranged from 3.5-22.8% and the FISH "mean spot ratio" 0.86-0.96. Immuno-flowFISH also detected a minimal residual disease case with +12 with a limit of detection of 0.13% and a rare case that presented with atypical phenotype and cytogenetics. Immuno-flowFISH could detect del(17p) in phenotypically identified CD5/CD19-positive B-cells. The 100-fold increase in analyzed cells, as well as the addition of cell phenotype increased the sensitivity and specificity over current clinical FISH testing. Furthermore, immuno-flowFISH analysis demonstrated specific utility in unique clinical scenarios such as residual disease and atypical biology cases which may be of significant benefit with regards to prognostication and MRD analysis. The method will assist in therapeutic decision making and disease monitoring for many hematological malignancies. © 2019 International Society for Advancement of Cytometry.

Search for an Optimal Design of a Bioprosthetic Venous Valve: In silico and in vitro Studies.

OBJECTIVE/BACKGROUND: Valve incompetence is a progressive disease of the venous system that may eventually lead to venous hypertension, pain, and ulcers. There is a need for a venous valve prosthesis to replace incompetent valves. Computational and experimental investigations on venous valve design and associated haemodynamics will undoubtedly advance prosthesis design and treatments. Here, the objective is to investigate the effect of venous valve on the fluid and solid mechanics. The hypothesis is that there exists a valve geometry that maximises leaflet shear stress (LSS) but minimises leaflet intramural stress (LIS; i.e., minimise stress ratio = LIS/LSS). METHODS: To address the hypothesis, fully dynamic fluid-structure interaction (FSI) models were developed. The entire cycle of valve opening and closure was simulated. The flow validation experiments were conducted using a stented venous valve prosthesis and a pulse duplicator flow loop. RESULTS: Agreement between the output of FSI simulations and output of pulse duplicator was confirmed. The maximum flow rates were within 6% difference, and the total flow during the cycle was within 10% difference. The simulated high stress ratio region at the leaflet base (five times the leaflet average) predicted the disease location of the vast majority of explanted venous valves reported in clinical literature. The study found that the reduced valve height and leaflet dome shape resulted in optimal performance to provide the lowest stress ratio. CONCLUSION: This study proposes an effective design of venous prostheses and elaborates on the correlations of venous valve with clinical observations.

Anti-Ebola therapy for patients with Ebola virus disease: a systematic review.

BACKGROUND: Management of Ebola virus disease (EVD) has historically focused on infection prevention, case detection and supportive care. Several specific anti-Ebola therapies have been investigated, including during the 2014-2016 West African outbreak. Our objective was to conduct a systematic review of the effect of anti-Ebola virus therapies on clinical outcomes to guide their potential use and future evaluation. METHODS: We searched PubMed, EMBASE, Global Health, Cochrane Library, African Index Medicus, WHOLIS (inception-9 April 2018), and trial registries for observational studies or clinical trials, in any language, that enrolled patients with confirmed EVD who received therapy targeting Ebola virus and reported on mortality, symptom duration, or adverse effects. RESULTS: From 11,257 citations and registered trials, we reviewed 55 full-text citations, of which 35 met eligibility criteria (1 randomized clinical trial (RCT), 8 non-randomized comparative studies, 9 case series and 17 case reports) and collectively examined 21 anti-Ebola virus agents. The 31 studies performed during the West African outbreak reported on 4.8% (1377/28616) of all patients with Ebola. The only RCT enrolled 72 patients (0.25% of all patients with Ebola) and compared the monoclonal antibody ZMapp vs. standard care (mortality, 22% vs. 37%; 95% confidence interval for risk difference, - 36 to 7%). Studies of convalescent plasma, interferon-ß-1a, favipiravir, brincidofovir, artesunate-amodiaquine and TKM-130803 were associated with at least moderate risk of bias. CONCLUSIONS: Research evaluating anti-Ebola virus agents has reached very few patients with EVD, and inferences are limited by non-randomized study designs. ZMapp has the most promising treatment signal.

A Laboratory Study on Effects of Cycling Helmet Fit on Biomechanical Measures Associated With Head and Neck Injury and Dynamic Helmet Retention.

There is a scant biomechanical literature that tests, in a laboratory setting, whether or not determinants of helmet fit affect biomechanical parameters associated with injury. Using conventional cycling helmets and repeatable models of the human head and neck, integrated into a guided drop impact experiment at speeds up to 6 m/s, this study tests the hypothesis that fit affects head kinematics, neck kinetics, and the extent to which the helmet moves relative to the underlying head (an indicator of helmet positional stability). While there were a small subset of cases where head kinematics were statistically significantly altered by fit, when viewed as a whole our measures of head kinematics suggest that fit does not systematically alter kinematics of the head secondary to impact. Similarly, when viewed as a whole, our data suggest that fit does not systematically alter resultant neck compression and resultant moment and associated biomechanical measures. Our data suggest that backward fit helmets exhibit the worst dynamic stability, in particular when the torso is impacted before the helmeted head is impacted, suggesting that the typical certification method of dynamical loading of a helmet to quantify retention may not be representative of highly plausible cycling incident scenarios where impact forces are first applied to the torso leading to loading of the neck prior to the head. Further study is warranted so that factors of fit that affect injury outcome are uncovered in both laboratory and real-world settings.

Pseudacteon Phorid Flies: Host Specificity and Impacts on Solenopsis Fire Ants.

Human commerce has resulted in the spread of the imported fire ants, Solenopsis species, worldwide. Six species of parasitic Pseudacteon phorid flies that are highly host specific to the Solenopsis saevissima complex of Solenopsis fire ants have been successfully released in the southern United States. The presence of Pseudacteon phorid flies, in addition to having direct mortality effects on their host ants, modifies foraging behavior and disrupts interspecific competition between host species and other ant species in the community. Fire ant workers have evolved effective methods to cope with parasitism pressure, which may relieve population-level impacts of introduced phorid flies. This review focuses on the mechanisms underlying host location, host preference, and host-size selection of Pseudacteon phorid flies and highlights their direct and indirect effects on fire ant populations. Knowledge gained from parasitoid-ant interactions will enhance use of natural enemies as biological control agents for invasive social insects.

Structural Control of Nonnative Ligand Binding in Engineered Mutants of Phosphoenolpyruvate Carboxykinase.

Protein engineering to alter recognition underlying ligand binding and activity has enormous potential. Here, ligand binding for Escherichia coli phosphoenolpyruvate carboxykinase (PEPCK), which converts oxaloacetate into CO2 and phosphoenolpyruvate as the first committed step in gluconeogenesis, was engineered to accommodate alternative ligands as an exemplary system with structural information. From our identification of bicarbonate binding in the PEPCK active site at the supposed CO2 binding site, we probed binding of nonnative ligands with three oxygen atoms arranged to resemble the bicarbonate geometry. Crystal structures of PEPCK and point mutants with bound nonnative ligands thiosulfate and methanesulfonate along with strained ATP and reoriented oxaloacetate intermediates and unexpected bicarbonate were determined and analyzed. The mutations successfully altered the bound ligand position and orientation and its specificity: mutated PEPCKs bound either thiosulfate or methanesulfonate but never both. Computational calculations predicted a methanesulfonate binding mutant and revealed that release of the active site ordered solvent exerts a strong influence on ligand binding. Besides nonnative ligand binding, one mutant altered the Mn2+ coordination sphere: instead of the canonical octahedral ligand arrangement, the mutant in question had an only five-coordinate arrangement. From this work, critical features of ligand binding, position, and metal ion cofactor geometry required for all downstream events can be engineered with small numbers of mutations to provide insights into fundamental underpinnings of protein-ligand recognition. Through structural and computational knowledge, the combination of designed and random mutations aids in the robust design of predetermined changes to ligand binding and activity to engineer protein function.