Cost-effectiveness analysis of biologics for the treatment of chronic rhinosinusitis with nasal polyps in Canada.

BACKGROUND: Dupilumab, omalizumab, and mepolizumab are the three biologics currently approved for use in CRSwNP in Canada. Despite evidence of efficacy, their cost-effectiveness, which is a key factor influencing prescribing patterns, has not yet been compared to each other. METHODS: A cost-effectiveness model using quality-adjusted life years (QALYs) was constructed using a Decision Tree Markov analysis. A third-party healthcare payer perspective and a 10-year time horizon was used. A willingness-to-pay (WTP) threshold of 50,000 Canadian dollars (CAD) per QALY was used to determine cost-effectiveness. Dupilumab, omalizumab, and mepolizumab were each compared to each other. RESULTS: Omalizumab was the most cost-effective biologic using current estimates of cost and efficacy in CRSwNP. Using omalizumab as a baseline, dupilumab had an ICER of $235,305/QALY. Mepolizumab was dominated by omalizumab and dupilumab at the current drug prices and estimates of efficacy. Sensitivity analyses determined that when increasing the WTP threshold to $150,000/QALY, dupilumab became cost-effective compared to omalizumab in 22.5% of simulation scenarios. Additionally, altering dosing frequency had a significant effect on cost-effectiveness. CONCLUSION: When comparing the relative cost-effectiveness of biologics in recalcitrant CRSwNP, omalizumab currently appears to be the most cost-effective option. Future reductions in drug prices, adjustments to currently approved dosing regimens, better patient selection, and improvements in sinus surgery outcomes will challenge the current cost-effectiveness models and necessitate reassessment as treatments for CRSwNP continue to evolve.

Cytosolic and mitochondrial translation elongation are coordinated through the molecular chaperone TRAP1 for the synthesis and import of mitochondrial proteins.

A complex interplay between mRNA translation and cellular respiration has been recently unveiled, but its regulation in humans is poorly characterized in either health or disease. Cancer cells radically reshape both biosynthetic and bioenergetic pathways to sustain their aberrant growth rates. In this regard, we have shown that the molecular chaperone TRAP1 not only regulates the activity of respiratory complexes, behaving alternatively as an oncogene or a tumor suppressor, but also plays a concomitant moonlighting function in mRNA translation regulation. Herein, we identify the molecular mechanisms involved, showing that TRAP1 (1) binds both mitochondrial and cytosolic ribosomes, as well as translation elongation factors; (2) slows down translation elongation rate; and (3) favors localized translation in the proximity of mitochondria. We also provide evidence that TRAP1 is coexpressed in human tissues with the mitochondrial translational machinery, which is responsible for the synthesis of respiratory complex proteins. Altogether, our results show an unprecedented level of complexity in the regulation of cancer cell metabolism, strongly suggesting the existence of a tight feedback loop between protein synthesis and energy metabolism, based on the demonstration that a single molecular chaperone plays a role in both mitochondrial and cytosolic translation, as well as in mitochondrial respiration.

Azithromycin Mechanisms of Action in CRS Include Epithelial Barrier Restoration and Type 1 Inflammation Reduction.

OBJECTIVE: Previous in vitro transcriptomic profiling suggests azithromycin exerts its effects in patients with chronic rhinosinusitis (CRS) via modulation of type 1 inflammation and restoration of epithelial barrier function. We wished to verify these postulated effects using in vitro models of epithelial repair and in vivo transcriptional profiling. STUDY DESIGN: Functional effects of azithromycin in CRS were verified using in vitro models of wounding. The mechanism of the effect of azithromycin was assessed in vivo using transcriptomic profiling. SETTING: Academic medical center. METHODS: Effects of azithromycin on the speed of epithelial repair were verified in a wounding model using primary nasal epithelial cells (pNEC) from CRS patients. Nasal brushings collected pre-and posttreatment during a placebo-controlled trial of azithromycin for CRS patients unresponsive to surgery underwent transcriptomic profiling to identify implicated pathways. RESULTS: Administration of azithromycin improved the wound healing rates in CRS pNECs and prevented the negative effect of Staphylococcus aureus on epithelial repair. In vivo, response to azithromycin was associated with downregulation in pathways of type 1 inflammation, and upregulation of pathways implicated in the restoration of the cell cycle. CONCLUSION: Restoration of healthy epithelial function may represent a major mode of action of azithromycin in CRS. In vitro models show enhanced epithelial repair, while in vivo transcriptomics shows downregulation of pathways type 1 inflammation accompanied by upregulation of DNA repair and cell-cycle pathways. The maximal effect in patients with high levels of type 1-enhanced inflammation suggests that azithromycin may represent a novel therapeutic option for surgery-unresponsive CRS patients.

Cytosolic and mitochondrial translation elongation are coordinated through the molecular chaperone TRAP1 for the synthesis and import of mitochondrial proteins.

A complex interplay between mRNA translation and cellular respiration has been recently unveiled, but its regulation in humans is poorly characterized in either health or disease. Cancer cells radically reshape both biosynthetic and bioenergetic pathways to sustain their aberrant growth rates. In this regard, we have shown that the molecular chaperone TRAP1 not only regulates the activity of respiratory complexes, behaving alternatively as an oncogene or a tumor suppressor, but also plays a concomitant moonlighting function in mRNA translation regulation. Herein we identify the molecular mechanisms involved, demonstrating that TRAP1: i) binds both mitochondrial and cytosolic ribosomes as well as translation elongation factors, ii) slows down translation elongation rate, and iii) favors localized translation in the proximity of mitochondria. We also provide evidence that TRAP1 is coexpressed in human tissues with the mitochondrial translational machinery, which is responsible for the synthesis of respiratory complex proteins. Altogether, our results show an unprecedented level of complexity in the regulation of cancer cell metabolism, strongly suggesting the existence of a tight feedback loop between protein synthesis and energy metabolism, based on the demonstration that a single molecular chaperone plays a role in both mitochondrial and cytosolic translation, as well as in mitochondrial respiration.

Association between neuroimaging findings and neurological sequelae in patients with congenital cytomegalovirus infection.

BACKGROUND: Congenital cytomegalovirus (CMV) infection is an important cause of disability. There is little evidence on the prognostic value of lesions identified in neuroimaging studies. AIM: The study aimed to assess the severity of lesions detected with brain MRI and transfontanellar ultrasound and their relationship with long-term neurological deficits. PATIENTS AND METHODS: We performed a retrospective, analytical, observational study of 36 patients with congenital CMV infection. Neuroimaging studies were reviewed and classified according to the modified Noyola' scale. Imaging findings were compared with neurological alterations in the patients' most recent follow-up evaluation at the paediatric neurology department. RESULTS: Thirty-six patients were studied (transfontanellar ultrasound: 30; brain MRI: 29). Twenty of 30 patients showed ultrasound abnormalities; of these, 11 showed alterations on brain MR images (P = .04) and 10 had neurological impairment (P = .008). Transfontanellar ultrasound had a sensitivity of 83.3%, 90% CI: 58-100 and a specificity of 44.4%, 90% CI: 18.7-70.2 for predicting neurological sequelae. Brain MRI displayed abnormalities in 20 of 29 patients, of whom 16 had neurological impairment (P < .001). MRI had a sensitivity of 94%, 95% CI: 80-100 and a specificity of 66.6%, 95% CI: 36-97.5 for predicting neurological sequelae. Modified Noyola' scale values > 2 were correlated with psychomotor retardation (P < .001). CONCLUSIONS: Our findings validate previous studies reporting a statistical significant correlation between the extension of neuroimaging lesions and severity of neurological deficits.

Efficacy and safety of benralizumab in chronic rhinosinusitis with nasal polyps: A randomized, placebo-controlled trial.

BACKGROUND: Eosinophilic inflammation has been implicated in the pathogenesis, severity, and treatment responsiveness of chronic rhinosinusitis with nasal polyps (CRSwNP). OBJECTIVE: We sought to assess the efficacy and safety of benralizumab-mediated eosinophil depletion for treating CRSwNP. METHODS: The phase 3 OSTRO study enrolled patients with severe CRSwNP who were symptomatic despite treatment with intranasal corticosteroids and who had a history of systemic corticosteroid (SCS) use and/or surgery for nasal polyps (NP). Patients were randomized 1:1 to treatment with benralizumab 30 mg or placebo every 4 weeks for the first 3 doses and every 8 weeks thereafter. Coprimary end points were change from baseline to week 40 in NP score (NPS) and patient-reported mean nasal blockage score reported once every 2 weeks. RESULTS: The study population comprised 413 randomized patients (207 in the benralizumab group and 206 in the placebo group). Benralizumab significantly improved NPS and nasal blockage score compared to placebo at week 40 (P ≤ .005). Improvements in Sinonasal Outcome Test 22 score at week 40, time to first NP surgery and/or SCS use for NP, and time to first NP surgery were not statistically significant between treatment groups. Nominal significance was obtained for improvement in difficulty in sense of smell score at week 40 (P = .003). Subgroup analyses suggested influences of comorbid asthma, number of NP surgeries, sex, body mass index, and baseline blood eosinophil count on treatment effects. Benralizumab was safe and well tolerated. CONCLUSION: Benralizumab, when added to standard-of-care therapy, reduced NPS, decreased nasal blockage, and reduced difficulty with sense of smell compared to placebo in patients with CRSwNP. TRIAL REGISTRATION: ClinicalTrials.gov NCT03401229.

The Effect of Radiation and Chemoradiation Therapy on the Head and Neck Mucosal Microbiome: A Review.

Radiation (RT) and chemoradiation therapy (CRT) play an essential role in head and neck cancer treatment. However, both cause numerous side effects in the oral cavity, paranasal sinuses, and pharynx, having deleterious consequences on patients' quality of life. Concomitant with significant advances in radiation oncology, much attention has turned to understanding the role of the microbiome in the pathogenesis of treatment-induced tissue toxicity, to ultimately explore microbiome manipulation as a therapeutic intervention. This review sought to discuss current publications investigating the impact of RT and CRT-induced changes on the head and neck microbiome, using culture-independent molecular methods, and propose opportunities for future directions. Based on 13 studies derived from a MEDLINE, EMBASE, and Web of Science search on November 7, 2021, use of molecular methods has uncovered various phyla and genera in the head and neck microbiome, particularly the oral microbiome, not previously known using culture-based methods. However, limited research has investigated the impact of RT/CRT on subsites other than the oral cavity and none of the studies aimed to examine the relationship between the head and neck microbiome and treatment effectiveness. Findings from this review provide helpful insights on our current understanding of treatment-induced oral mucositis, dental plaque, and caries formation and highlight the need for future research to examine the effect of RT/CRT on the sinonasal and oropharyngeal microbiome. In addition, future research should use larger cohorts, examine the impact of the microbiome on treatment response, and study the effect of manipulating the microbiome to overcome therapy resistance.

Ataluren and aminoglycosides stimulate read-through of nonsense codons by orthogonal mechanisms.

During protein synthesis, nonsense mutations, resulting in premature stop codons (PSCs), produce truncated, inactive protein products. Such defective gene products give rise to many diseases, including cystic fibrosis, Duchenne muscular dystrophy (DMD), and some cancers. Small molecule nonsense suppressors, known as TRIDs (translational read-through-inducing drugs), stimulate stop codon read-through. The best characterized TRIDs are ataluren, which has been approved by the European Medicines Agency for the treatment of DMD, and G418, a structurally dissimilar aminoglycoside. Previously [1], we applied a highly purified in vitro eukaryotic translation system to demonstrate that both aminoglycosides like G418 and more hydrophobic molecules like ataluren stimulate read-through by direct interaction with the cell's protein synthesis machinery. Our results suggested that they might do so by different mechanisms. Here, we pursue this suggestion through a more-detailed investigation of ataluren and G418 effects on read-through. We find that ataluren stimulation of read-through derives exclusively from its ability to inhibit release factor activity. In contrast, G418 increases functional near-cognate tRNA mispairing with a PSC, resulting from binding to its tight site on the ribosome, with little if any effect on release factor activity. The low toxicity of ataluren suggests that development of new TRIDs exclusively directed toward inhibiting termination should be a priority in combatting PSC diseases. Our results also provide rate measurements of some of the elementary steps during the eukaryotic translation elongation cycle, allowing us to determine how these rates are modified when cognate tRNA is replaced by near-cognate tRNA ± TRIDs.

The Role of Biologics in Chronic Rhinosinusitis with Nasal Polyps.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common and heterogeneous inflammatory disease of the upper respiratory tract. This article provides expert opinion and points of view from both allergists and rhinologists who specialize in CRSwNP. Despite the potential value of biomarker-based endotyping to provide guidance regarding optimal care and treatment choices for patients with CRSwNP, current practice is largely not biomarker-based. In general, there is agreement that for patients with symptomatic CRSwNP who have failed a trial of a course of at least 3 months of intranasal steroids and a short course of oral corticosteroids, a surgical intervention will often be the next treatment of choice. Biologics may be considered before an initial surgery in patients with comorbid severe asthma and in those for whom surgery is less available, refused by the patient, or likely to be associated with a higher-than-average complication rate. Biologic use immediately following surgery may be considered in patients who have a history of nasal polyp recurrence within 12 months of a prior surgery. For many patients with recalcitrant disease, a combination of sinus surgery and use of a biologic that is targeted to their precise endotype may be the optimal treatment strategy, though which surgical approach and which biologics are best for each patient are debates that remain ongoing.

A scoping review of polypharmacy interventions in patients with stroke, heart disease and diabetes.

Background Patients with cardiometabolic disease, specifically, stroke, heart disease and diabetes have a high prevalence of polypharmacy. Interventions to better manage or reduce polypharmacy in these populations may help improve patient outcomes. However, there is a paucity of data in this area, which needs to be investigated. Aim of the review The purpose of this scoping review was to identify and synthesize the available evidence pertaining to polypharmacy interventions in patients with cardiometabolic disease(s) and to determine what outcomes measures are assessed in these studies. Methods We followed an evidence-based scoping review guiding framework to address our study objectives. Three electronic databases (MEDLINE, EMBASE, CINAHL) were searched for all relevant studies up to May 2019. The Cochrane Library was also searched; studies included in relevant reviews were screened for inclusion. Reference lists of all included papers were also manually reviewed to identify additional articles. Polypharmacy interventions and measures used to assess efficacy were qualitatively described. Results Overall, six studies met the inclusion criteria. The majority of interventions were clinical pharmacist interventions reporting on a variety of outcomes including surrogate markers, quality of life and patient satisfaction, drug-related problems, and healthcare utilization and costs. The findings from the included studies generally indicated positive effects but had high risk of bias. Conclusions Existing polypharmacy interventions have some efficacy at improving a variety of patient and healthcare system outcomes. Increased frequency and duration of follow-up with patients led to significant improvements in quality of life, disease control and cost-savings in outpatient and in-patient settings. However, our analysis of the identified studies suggests low-quality evidence and significant knowledge gaps regarding patients with stroke and cardiometabolic multimorbidity. This signals a need for further high-quality research to both confirm these findings and include these other high-risk patient populations to validate these findings.

Tumor necrosis factor stimulates fibroblast growth factor 23 levels in chronic kidney disease and non-renal inflammation.

Fibroblast growth factor 23 (FGF23) regulates phosphate homeostasis, and its early rise in patients with chronic kidney disease is independently associated with all-cause mortality. Since inflammation is characteristic of chronic kidney disease and associates with increased plasma FGF23 we examined whether inflammation directly stimulates FGF23. In a population-based cohort, plasma tumor necrosis factor (TNF) was the only inflammatory cytokine that independently and positively correlated with plasma FGF23. Mouse models of chronic kidney disease showed signs of renal inflammation, renal FGF23 expression and elevated systemic FGF23 levels. Renal FGF23 expression coincided with expression of the orphan nuclear receptor Nurr1 regulating FGF23 in other organs. Antibody-mediated neutralization of TNF normalized plasma FGF23 and suppressed ectopic renal Fgf23 expression. Conversely, TNF administration to control mice increased plasma FGF23 without altering plasma phosphate. Moreover, in Il10-deficient mice with inflammatory bowel disease and normal kidney function, plasma FGF23 was elevated and normalized upon TNF neutralization. Thus, the inflammatory cytokine TNF contributes to elevated systemic FGF23 levels and also triggers ectopic renal Fgf23 expression in animal models of chronic kidney disease.

Association between neuroimaging findings and neurological sequelae in patients with congenital cytomegalovirus infection. / Asociación entre neuroimagen y secuelas neurológicas en pacientes con infección congénita por citomegalovirus.

BACKGROUND: Congenital cytomegalovirus (CMV) infection is an important cause of disability. There is little evidence on the prognostic value of lesions identified in neuroimaging studies. AIM: The study aimed to assess the severity of lesions detected with brain MRI and transfontanellar ultrasound and their relationship with long-term neurological deficits. PATIENTS AND METHODS: We performed a retrospective, analytical, observational study of 36 patients with congenital CMV infection. Neuroimaging studies were reviewed and classified according to the modified Noyola' scale. Imaging findings were compared with neurological alterations in the patients' most recent follow-up evaluation at the paediatric neurology department. RESULTS: Thirty-six patients were studied (transfontanellar ultrasound: 30; brain MRI: 29). Twenty of 30 patients showed ultrasound abnormalities; of these, 11 showed alterations on brain MR images (P=.04) and 10 had neurological impairment (P=.008). Transfontanellar ultrasound had a sensitivity of 83.3%, 90% CI: 58-100 and a specificity of 44.4%, 90% CI: 18.7-70.2 for predicting neurological sequelae. Brain MRI displayed abnormalities in 20 of 29 patients, of whom 16 had neurological impairment (P<.001). MRI had a sensitivity of 94%, 95% CI: 80-100 and a specificity of 66.6%, 95% CI: 36-97.5 for predicting neurological sequelae. Modified Noyola' scale values >2 were correlated with psychomotor retardation (P<.001). CONCLUSIONS: Our findings validate previous studies reporting a statistical significant correlation between the extension of neuroimaging lesions and severity of neurological deficits.

Staphylococcus aureus impairs sinonasal epithelial repair: Effects in patients with chronic rhinosinusitis with nasal polyps and control subjects.

BACKGROUND: The effect of Staphylococcus aureus on nasal epithelial repair has never been assessed in patients with chronic rhinosinusitis with nasal polyps (CRSwNP). OBJECTIVE: This study aimed to determine whether (1) nasal epithelial cell cultures from patients with CRSwNP and control subjects repair differently; (2) S aureus exoproducts compromise nasal epithelial repair; (3) S aureus alters lamellipodial dynamics; and (4) deleterious effects could be counteracted by the Rho-associated coiled-coil kinase inhibitor Y-27632. METHODS: Primary nasal epithelial cells (pNECs) collected during surgeries were cultured and injured under 3 conditions: (1) basal conditions, (2) exposed to S aureus exoproducts, and (3) exposed to S aureus exoproducts and Y-27632. Epithelial repair, lamellipodial dynamics, and cytoskeletal organization were assessed. RESULTS: Under basal conditions, pNEC cultures from patients with CRSwNP presented significantly lower repair rates and reduced lamellipodial protrusion length and velocity than those from control subjects. S aureus exoproducts significantly decreased repair rates and protrusion dynamics in both control subjects and patients with CRSwNP; however, the effect of S aureus on cell protrusions was more sustained over time in patients with CRSwNP. Under basal conditions, immunofluorescence assays showed significantly reduced percentages of cells with lamellipodia at the wound edge in patients with CRSwNP compared with control subjects. S aureus altered cell polarity and decreased the percentage of cells with lamellipodia in both groups. Finally, Y-27632 prevented the deleterious effects of S aureus exoproducts on CRSwNP repair rates, as well as on lamellipodial dynamics and formation. CONCLUSIONS: S aureus exoproducts significantly alter epithelial repair and lamellipodial dynamics on pNECs, and this impairment was more pronounced in patients with CRSwNP. Importantly, Y-27632 restored epithelial repair and lamellipodial dynamics in the presence of S aureus exoproducts.

Fibroblast Growth Factor 23 Expression Is Increased in Multiple Organs in Mice With Folic Acid-Induced Acute Kidney Injury.

Fibroblast growth factor 23 (FGF23) regulates phosphate homeostasis and vitamin D metabolism. In patients with acute kidney injury (AKI), FGF23 levels rise rapidly after onset of AKI and are associated with AKI progression and increased mortality. In mouse models of AKI, excessive rise in FGF23 levels is accompanied by a moderate increase in FGF23 expression in bone. We examined the folic acid-induced AKI (FA-AKI) mouse model to determine whether other organs contribute to the increase in plasma FGF23 and assessed the vitamin D axis as a possible trigger for increased Fgf23 gene expression. Twenty-four hours after initiation of FA-AKI, plasma intact FGF23 and 1,25(OH)2D were increased and kidney function declined. FA-treated mice developed renal inflammation as shown by increased Tnf and Tgfb mRNA expression. Fgf23 mRNA expression was 5- to 15-fold upregulated in thymus, spleen and heart of FA-treated mice, respectively, but only 2-fold in bone. Ectopic renal Fgf23 mRNA expression was also detected in FA-AKI mice. Plasma FGF23 and Fgf23 mRNA expression in thymus, spleen, heart, and bone strongly correlated with renal Tnf mRNA expression. Furthermore, Vdr mRNA expression was upregulated in spleen, thymus and heart and strongly correlated with Fgf23 mRNA expression in the same organ. In conclusion, the rapid rise in plasma FGF23 in FA-AKI mice is accompanied by increased Fgf23 mRNA expression in multiple organs and increased Vdr expression in extra osseous tissues together with increased plasma 1,25(OH)2D and inflammation may trigger the rise in FGF23 in FA-AKI.

Staphylococcus aureus on Sinus Culture Is Associated With Recurrence of Chronic Rhinosinusitis After Endoscopic Sinus Surgery.

Objectives: Identify whether identification of S. aureus on conventional culture is a predictor of success or failure after ESS followed by budesonide nasal irrigations (BUD) in chronic rhinosinusitis (CRS) patients at high risk of recurrence. Methodology: Prospective clinical trial including 116 patients from a tertiary care center at high-risk of disease recurrence following ESS+BUD. Blood samples, microbial swabs, and SNSS/SNOT-22 were taken on the day of surgery (Visit-1) and 4 months postoperatively (Visit-2). Outcomes were evaluated using symptoms and mucosal status as assessed by the Lund-Kennedy endoscopic score. Results: Seventy-five patients (69.4%) attained SNOT-22 MCID or higher. (Mean = 33.4, range 9-75). Objective documentation of recurrence of disease, as defined by combined endoscopic/symptomatic criteria, was noted in 58/116 patients (50%). Revision surgery was associated with a significantly higher rate of disease recurrence (60.0 vs. 28.0%; p < 0.001). Culture for Staphylococcus aureus was associated with disease recurrence, preoperatively and at 4 months post-surgery (p = 0.020; p < 0.001). This was restricted to post-operative cultures in the revision group (10.0 vs. 48.8%; p < 0.001). Other factors associated with poor outcome included intolerance to non-steroidal anti-inflammatory drugs (NSAID) (p = 0.036). Significantly higher Lund-Kennedy scores in the recurrence groups despite similar symptom intensity, emphasizing the importance of considering objective outcome in addition to patient-reported ones. Conclusion: Patients undergoing revision ESS are at high risk of disease recurrence, even when budesonide irrigations are used post operatively. Presence of S. aureus on culture pre-operatively or at 4 months post-ESS is associated with a negative outcome. This suggests that S. aureus negatively influences outcome, possibly via a number of mechanisms, including interactions with the (i) immune system, (ii) regeneration and repair of the sinus epithelium, or (iii) via interference with the sinus microbiome. This suggests that S. aureus may be a simple and inexpensive biomarker for disease severity and indicates a clear need to better appreciate S. aureus on how it contributes mechanistically to disease development and persistence in order to develop targeted therapeutic strategies.

New in Vitro Assay Measuring Direct Interaction of Nonsense Suppressors with the Eukaryotic Protein Synthesis Machinery.

Nonsense suppressors (NonSups) induce "readthrough", i.e., the selection of near cognate tRNAs at premature termination codons and insertion of the corresponding amino acid into nascent polypeptide. Prior readthrough measurements utilized contexts in which NonSups can promote readthrough directly, by binding to one or more of the components of the protein synthesis machinery, or indirectly, by several other mechanisms. Here we utilize a new, highly purified in vitro assay to measure exclusively direct nonsense suppressor-induced readthrough. Of 16 NonSups tested, 12 display direct readthrough, with results suggesting that such NonSups act by at least two different mechanisms. In preliminary work we demonstrate the potential of single molecule fluorescence energy transfer measurements to elucidate mechanisms of NonSup-induced direct readthrough, which will aid efforts to identify NonSups having improved clinical efficacy.

Kinetics of initiating polypeptide elongation in an IRES-dependent system.

The intergenic IRES of Cricket Paralysis Virus (CrPV-IRES) forms a tight complex with 80S ribosomes capable of initiating the cell-free synthesis of complete proteins in the absence of initiation factors. Such synthesis raises the question of what effect the necessary IRES dissociation from the tRNA binding sites, and ultimately from all of the ribosome, has on the rates of initial peptide elongation steps as nascent peptide is formed. Here we report the first results measuring rates of reaction for the initial cycles of IRES-dependent elongation. Our results demonstrate that 1) the first two cycles of elongation proceed much more slowly than subsequent cycles, 2) these reduced rates arise from slow pseudo-translocation and translocation steps, and 3) the retarding effect of ribosome-bound IRES on protein synthesis is largely overcome following translocation of tripeptidyl-tRNA. Our results also provide a straightforward approach to detailed mechanistic characterization of many aspects of eukaryotic polypeptide elongation.

Targeted control of the saddle gall midge, Haplodiplosis marginata (von Roser) (Diptera: Cecidomyiidae), and the benefits of good control of this pest to winter wheat yield.

BACKGROUND: Since 2010 there has been a resurgence of the saddle gall midge, Haplodiplosis marginata (von Roser), in Belgium and several other European countries, with this pest sometimes causing severe damage in cereals. In 2012 and 2013, field trials were conducted in heavily infested fields to assess its impact on winter wheat crops and to determine efficient ways of dealing with severe infestations. RESULTS: Crop exposure to H. marginata varied with the different protection methods tried. These methods included 1-4 successive applications of lambda-cyhalothrin. Yield losses were significant, reaching 6% in 2012 and as high as 15% in 2013, and these losses were linearly related to the number of galls on stems. CONCLUSION: The trials showed that insecticide applications needed to be synchronised with H. marginata flight peaks and to target the egg hatching period. They also revealed that insecticides applied to coincide with the first flight could, in humid conditions, also reach the larvae close to the soil surface, prior to their pupation.