Editor's Choice - Comparison of Open Surgery and Endovascular Techniques for Juxtarenal and Complex Neck Aortic Aneurysms: The UK COMPlex AneurySm Study (UK-COMPASS) - Peri-operative and Midterm Outcomes.

OBJECTIVE: Treatment of juxtarenal and complex neck abdominal aortic aneurysms (AAAs) is now commonly by endovascular rather than open surgical repair (OSR). Published comparisons show poor validity and scientific precision. UK-COMPASS is a comparative cohort study of endovascular treatments vs. OSR for patients with an AAA unsuitable for standard on label endovascular aneurysm repair (EVAR). METHODS: All procedures for AAA in England (November 2017 to October 2019) were identified, AAA anatomy assessed in a Corelab, peri-operative risk scores determined, and propensity scoring used to identify patients suitable for either endovascular treatment or OSR. Patients were stratified by aneurysm neck length (0 - 4 mm, 5 - 9 mm, or ≥ 10 mm) and operative risk; the highest quartile was considered high risk and the remainder standard risk. Death was the primary outcome measure. Endovascular treatments included fenestrated EVAR (FEVAR) and off label standard EVAR (± adjuncts). RESULTS: Among 8 994 patients, 2 757 had AAAs that were juxtarenal, short neck, or complex neck in morphology. Propensity score stratification and adjustment method comparisons included 1 916 patients. Widespread off label use of standard EVAR devices was noted (35.6% of patients). The adjusted peri-operative mortality rate was 2.9%, lower for EVAR (1.2%; p = .001) and FEVAR (2.2%; p = .001) than OSR (4.5%). In standard risk patients with a 0 - 4 mm neck, the mortality rate was 7.4% following OSR and 2.3% following FEVAR. Differences were smaller for patients with a neck length ≥ 5 mm: 2.1% OSR vs. 1.0% FEVAR. At 3.5 years of follow up, the overall mortality rate was 20.7% in the whole study population, higher following FEVAR (27.6%) and EVAR (25.2%) than after OSR (14.2%). However, in the 0 - 4 mm neck subgroup, overall survival remained equivalent. The aneurysm related mortality rate was equivalent between treatments, but re-intervention was more common after EVAR and FEVAR than OSR. CONCLUSION: FEVAR proves notably safer than OSR in the peri-operative period for juxtarenal aneurysms (0 - 4 mm neck length), with comparable midterm survival. For patients with short neck (5 - 9 mm) and complex neck (≥ 10 mm) AAAs, overall survival was worse in endovascularly treated patients compared with OSR despite relative peri-operative safety. This warrants further research and a re-appraisal of the current clinical application of endovascular strategies, particularly in patients with poor general survival outlook owing to comorbidity and age.

GATA4 and GATA6 loss-of-expression is associated with extinction of the classical programme and poor outcome in pancreatic ductal adenocarcinoma.

OBJECTIVE: GATA6 is a key regulator of the classical phenotype in pancreatic ductal adenocarcinoma (PDAC). Low GATA6 expression associates with poor patient outcome. GATA4 is the second most expressed GATA factor in the pancreas. We assessed whether, and how, GATA4 contributes to PDAC phenotype and analysed the association of expression with outcome and response to chemotherapy. DESIGN: We analysed PDAC transcriptomic data, stratifying cases according to GATA4 and GATA6 expression and identified differentially expressed genes and pathways. The genome-wide distribution of GATA4 was assessed, as well as the effects of GATA4 knockdown. A multicentre tissue microarray study to assess GATA4 and GATA6 expression in samples (n=745) from patients with resectable was performed. GATA4 and GATA6 levels were dichotomised into high/low categorical variables; association with outcome was assessed using univariable and multivariable Cox regression models. RESULTS: GATA4 messenger RNA is enriched in classical, compared with basal-like tumours. We classified samples in 4 groups as high/low for GATA4 and GATA6. Reduced expression of GATA4 had a minor transcriptional impact but low expression of GATA4 enhanced the effects of GATA6 low expression. GATA4 and GATA6 display a partially overlapping genome-wide distribution, mainly at promoters. Reduced expression of both proteins in tumours was associated with the worst patient survival. GATA4 and GATA6 expression significantly decreased in metastases and negatively correlated with basal markers. CONCLUSIONS: GATA4 and GATA6 cooperate to maintain the classical phenotype. Our findings provide compelling rationale to assess their expression as biomarkers of poor prognosis and therapeutic response.

Editor's Choice - Comparison of Open, Standard, and Complex Endovascular Aortic Repair Treatments for Juxtarenal/Short Neck Aneurysms: A Systematic Review and Network Meta-Analysis.

OBJECTIVE: Abdominal aortic aneurysms (AAAs) with adverse morphology of the aneurysm neck are "complex". Techniques employed to repair complex aneurysms include open surgical repair (OSR) and a number of on label endovascular techniques such as fenestrated endovascular aneurysm repair (FEVAR) and endovascular aneurysm repair (EVAR) with adjuncts (including chimneys and endo-anchors), as well as off label use of standard EVAR. The aim was to conduct a network meta-analysis (NMA) of published comparative outcomes. DATA SOURCES: An electronic search was performed in Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials (CENTRAL). These databases were interrogated using the PubMed interface and the Healthcare Databases Advanced Search (HDAS) interface developed by the National Institute of Health and Care Excellence. REVIEW METHODS: Online databases were interrogated up to April 2020. Studies were included if they compared outcomes between at least two methods of repair for complex aneurysms (those with at least one adverse neck feature: absent/short neck, conicality, angulation, calcification, large diameter, and thrombus). The primary outcome measure was peri-operative death. Pre-registration was done in PROSPERO (CRD42020177482). RESULTS: The search identified 24 observational studies and 7854 patients who underwent OSR, FEVAR, off label EVAR, or chimney EVAR. No comparative studies included EVAR with endo-anchors. NMA was performed on 23 studies that reported outcomes of aneurysms with short/absent infrarenal neck. Compared with OSR, off label EVAR (relative risk [RR] 0.10, 95% confidence interval [CI] 0.01 - 0.41) and FEVAR (RR 0.62, 95% CI 0.32-0.94) were associated with lower peri-operative mortality. This difference was not seen at the midterm follow up (30 months). Compared with OSR, FEVAR was associated with a lower peri-operative myocardial infarction (MI) rate (RR 0.37, 95% CI 0.16 - 0.62) but a higher midterm re-intervention rate (hazard ratio 1.65, 95% CI 1.04 - 2.66). All studies had a "moderate" or "high" risk of bias. Confidence in the network findings (GRADE) was generally "low". CONCLUSION: This NMA demonstrated a peri-operative survival benefit for off label EVAR and FEVAR compared with OSR, potentially due to reduced risk of MI. FEVAR carries a greater midterm re-intervention risk than OSR, with potential implications for cost effectiveness. There is paucity of comparative data for cases with adverse neck features other than short length.

The mechanism of eukaryotic translation initiation and principles of its regulation.

Protein synthesis is principally regulated at the initiation stage (rather than during elongation or termination), allowing rapid, reversible and spatial control of gene expression. Progress over recent years in determining the structures and activities of initiation factors, and in mapping their interactions in ribosomal initiation complexes, have advanced our understanding of the complex translation initiation process. These developments have provided a solid foundation for studying the regulation of translation initiation by mechanisms that include the modulation of initiation factor activity (which affects almost all scanning-dependent initiation) and through sequence-specific RNA-binding proteins and microRNAs (which affect individual mRNAs).

Kernel hazard estimation for visualisation of the effect of a continuous covariates on time-to-event endpoints.

The problem of associating a continuous covariate, or biomarker, against a time-to-event outcome, is that it often requires categorisation of the covariate. This can lead to bias, loss of information and a poor representation of any underlying relationship. Here, two methods are proposed for estimating the effects of a continuous covariate on a time-to-event endpoint using weighted kernel estimators. The first method aims to estimate a density function for a time-to-event endpoint conditional on some covariate value whilst the second uses a joint density estimator. The results are visualisations in the form of surface plots that show the effects of a covariate without any need for categorisation. Both methods can aid interpretation and analysis of covariates against a time-to-event endpoint.

Sternocostal slipping rib syndrome.

PURPOSE: Classical slipping rib syndrome (SRS) can be subclassified based on anatomical location. We describe our experience with three patients suffering from symptomatic sternocostal slipping rib syndrome (SCSRS), a much less common variant of SRS. METHODS: This was a retrospective review of patients with SRS from 1988 to 2016. Described is our experience. RESULTS: Of 44 patients identified with SRS, three patients underwent operations for SCSRS variant. All three had significant pain and point tenderness at the sternocostal junction, and all experienced a popping sensation localized to this area. The mean age at onset was 14.3 years and mean time to diagnosis was 1.3 years. All patients experienced total resolution of symptoms following localized excision of the offending cartilage. CONCLUSIONS: A high index of suspicion based on history and physical examination are key to the early diagnosis of SCSRS. Excision of the symptomatic cartilage is effective for treatment.

Polypyrimidine tract binding protein stabilizes the encephalomyocarditis virus IRES structure via binding multiple sites in a unique orientation.

Polypyrimidine tract binding (PTB) protein is a regulator of alternative pre-mRNA splicing, and also stimulates the initiation of translation dependent on many viral internal ribosome entry segments/sites (IRESs). It has four RNA-binding domains (RBDs), but although the contacts with many IRESs have been mapped, the orientation of binding (i.e., which RBD binds to which site in the IRES) is unknown. To answer this question, 16 derivatives of PTB1, each with a single cysteine flanking the RNA-binding surface in an RBD, were constructed and used in directed hydroxyl radical probing with the encephalomyocarditis virus IRES. The results, together with mass spectrometry data on the stoichiometry of PTB binding to different IRES derivatives, show that the minimal IRES binds a single PTB in a unique orientation, with RBD1 and RBD2 binding near the 3' end, and RBD3 contacting the 5' end, thereby constraining and stabilizing the three-dimensional structural fold of the IRES.

Nd:YAG laser therapy for rectal and vaginal venous malformations.

BACKGROUND: Limited therapeutic options exist for rectal and vaginal venous malformations (VM). We describe our center's experience using Nd:YAG laser for targeted ablation of abnormal veins to treat mucosally involved pelvic VM. METHODS: Records of patients undergoing non-contact Nd:YAG laser therapy of pelvic VM at a tertiary children's hospital were reviewed. Symptoms, operative findings and details, complications, and outcomes were evaluated. RESULTS: Nine patients (age 0-24) underwent Nd:YAG laser therapy of rectal and/or vaginal VM. Rectal bleeding was present in all patients and vaginal bleeding in all females (n = 5). 5/7 patients had extensive pelvic involvement on MRI. Typical settings were 30 (rectum) and 20-25 W (vagina), with 0.5-1.0 s pulse duration. Patients underwent the same-day discharge. Treatment intervals ranged from 14 to 180 (average = 56) weeks, with 6.1-year mean follow-up. Five patients experienced symptom relief with a single treatment. Serial treatments managed recurrent bleeding successfully in all patients, with complete resolution of vaginal lesions in 40% of cases. No complications occurred. CONCLUSIONS: Nd:YAG laser treatment of rectal and vaginal VM results in substantial improvement and symptom control, with low complication risk. Given the high morbidity of surgical resection, Nd:YAG laser treatment of pelvic VM should be considered as first line therapy.

The organization of RNA contacts by PTB for regulation of FAS splicing.

Post-transcriptional steps of gene expression are regulated by RNA binding proteins. Major progress has been made in characterizing RNA-protein interactions, from high resolution structures to transcriptome-wide profiling. Due to the inherent technical challenges, less attention has been paid to the way in which proteins with multiple RNA binding domains engage with target RNAs. We have investigated how the four RNA recognition motif (RRM) domains of Polypyrimidine tract binding (PTB) protein, a major splicing regulator, interact with FAS pre-mRNA under conditions in which PTB represses FAS exon 6 splicing. A combination of tethered hydroxyl radical probing, targeted inactivation of individual RRMs and single molecule analyses revealed an unequal division of labour between the four RRMs of PTB. RNA binding by RRM4 is the most important for function despite the low intrinsic binding specificity and the complete lack of effect of disrupting individual RRM4 contact points on the RNA. The ordered RRM3-4 di-domain packing provides an extended binding surface for RNA interacting at RRM4, via basic residues in the preceding linker. Our results illustrate how multiple alternative low-specificity binding configurations of RRM4 are consistent with repressor function as long as the overall ribonucleoprotein architecture provided by appropriate di-domain packing is maintained.

The mechanism of translation initiation on Aichivirus RNA mediated by a novel type of picornavirus IRES.

Picornavirus mRNAs contain IRESs that sustain their translation during infection, when host protein synthesis is shut off. The major classes of picornavirus IRESs (Types 1 and 2) have distinct structures and sequences, but initiation on both is determined by their specific interaction with eIF4G. We report here that Aichivirus (AV), a member of the Kobuvirus genus of Picornaviridae, contains an IRES that differs structurally from Type 1 and Type 2 IRESs. Its function similarly involves interaction with eIF4G, but its eIF4G-interacting domain is structurally distinct, although it contains an apical eIF4G-interacting motif similar to that in Type 2 IRESs. Like Type 1 and Type 2 IRESs, AV IRES function is enhanced by pyrimidine tract-binding protein (PTB), but the pattern of PTB's interaction with each of these IRESs is distinct. Unlike all known IRESs, the AV IRES is absolutely dependent on DHX29, a requirement imposed by sequestration of its initiation codon in a stable hairpin.

Public awareness of and support for infrastructure changes designed to increase walking and biking in Los Angeles County.

OBJECTIVE: Policies to promote active transportation are emerging as a best practice to increase physical activity, yet relatively little is known about public opinion on utilizing transportation funds for such investments. This study sought to assess public awareness of and support for investments in walking and biking infrastructure in Los Angeles County. METHOD: In the fall of 2013, the Los Angeles County Department of Public Health conducted a telephone survey with a random sample of registered voters in the region. The survey asked respondents to report on the presence and importance of walking and biking infrastructure in their community, travel behaviors and preferences, and demographics. RESULTS: One thousand and five interviews were completed (response rate 20%, cooperation rate 54%). The majority of participants reported walking, biking, and bus/rail transportation investments as being important. In addition, participants reported a high level of support for redirecting transportation funds to active transportation investment - the population average was 3.28 (between 'strongly' and 'somewhat' support) on a 4 point Likert scale. CONCLUSION: Voters see active transportation infrastructure as being very important and support redirecting funding to improve the infrastructure. These findings can inform policy-decisions and planning efforts in the jurisdiction.

Polypyrimidine tract-binding protein stimulates the poliovirus IRES by modulating eIF4G binding.

Tethered hydroxyl-radical probing has been used to determine the orientation of binding of polypyrimidine tract-binding protein (PTB) to the poliovirus type 1 (Mahoney) (PV-1(M)) internal ribosome entry site/segment (IRES)-the question of which RNA-binding domain (RBD) binds to which sites on the IRES. The results show that under conditions in which PTB strongly stimulates IRES activity, a single PTB is binding to the IRES, a finding which was confirmed by mass spectrometry of PTB/IRES complexes. RBDs1 and 2 interact with the basal part of the Domain V irregular stem loop, very close to the binding site of eIF4G, and RBDs3 and 4 interact with the single-stranded regions flanking Domain V. The binding of PTB is subtly altered in the presence of the central domain (p50) of eIF4G, and p50 binding is likewise modified if PTB is present. This suggests that PTB stimulates PV-1(M) IRES activity by inducing eIF4G to bind in the optimal position and orientation to promote internal ribosome entry, which, in PV-1(M), is at an AUG triplet 30 nt downstream of the base of Domain V.

Activation of picornaviral IRESs by PTB shows differential dependence on each PTB RNA-binding domain.

Polypyrimidine tract binding protein (PTB) is an RNA-binding protein with four RNA-binding domains (RBDs). It is a major regulator of alternative splicing and also stimulates translation initiation at picornavirus IRESs (internal ribosome entry sites). The sites of interaction of each RBD with two picornaviral IRESs have previously been mapped. To establish which RBD-IRES interactions are essential for IRES activation, point mutations were introduced into the RNA-binding surface of each RBD. Three such mutations were sufficient to inactivate RNA-binding by any one RBD, but the sites of the other three RBD-IRES interactions remained unperturbed. Poliovirus IRES activation was abrogated by inactivation of RBD1, 2, or 4, but the RBD3-IRES interaction was superfluous. Stimulation of the encephalomyocarditis virus IRES was reduced by inactivation of RBD1, 3, or 4, and abrogated by mutation of RBD2, or both RBDs 3 and 4. Surprisingly, therefore, the binding of PTB in its normal orientation does not guarantee IRES activation; three native RBDs are sufficient for correct binding but not for activation if the missing RBD-IRES interaction is critical.

Activation of a microRNA response in trans reveals a new role for poly(A) in translational repression.

Here, we report that the untreated rabbit reticulocyte lysate contains over 300 different endogenous microRNAs together with the major components of the RNA-induced silencing complex and thus can be used as a model in vitro system to study the effects of microRNAs on gene expression. By using this system, we were able to show that microRNA hybridization to its target resulted in a very rapid and strong inhibition of expression that was exerted exclusively at the level of translation initiation with no involvement of transcript degradation or deadenylation. Moreover, we demonstrate that the magnitude of microRNA-induced repression can only be recapitulated in the context of a competitive translating environment. By using a wide spectrum of competitor cellular and viral RNAs, we could further show that competition was not exerted at the level of general components of the translational machinery, but relied exclusively on the presence of the poly(A) tail with virtually no involvement of the cap structure.

Differential effects of nucleotide analogs on scanning-dependent initiation and elongation of mammalian mRNA translation in vitro.

Codon-anticodon interactions are central to both the initiation and elongation phases of eukaryotic mRNA translation. The obvious difference is that the interaction takes place in the ribosomal A-site during elongation, whereas the 40S ribosomal subunit and associated initiation factors scan the mRNA sequence in search of an initiation codon with Met-tRNA(i) bound in the P-site, ceasing once codon-anticodon interaction is established at the AUG. As an indirect test of whether the two mechanisms of mRNA sequence inspection are basically similar or not, the effects of six different uridine analog substitutions in the mRNA were examined in reticulocyte lysate translation assays and 80S initiation complex formation assays. Four constructs, each with the same reporter coding sequence, were used, differing in whether the initiation codon was AUG or ACG, and in whether the 5'-UTR had U residues or not. Three analogs (5-bromoU, 5-aminoallylU, and pseudoU) inhibited both elongation and initiation, but the other three had striking differential effects. Ribothymidine had a negligible effect on elongation but caused a approximately 50% inhibition of initiation, with little effect on actual AUG recognition, which implies that inhibition must have occurred at some earlier step in initiation. In complete contrast, 2' deoxyU was prohibitive to elongation but had no effect on initiation, and 4-thioU actually stimulated initiation but quite strongly inhibited elongation processivity. These results show that the detailed mechanisms of inspection of the mRNA sequence during scanning-dependent initiation and elongation must be considerably different.

Mechanisms governing the selection of translation initiation sites on foot-and-mouth disease virus RNA.

Translation initiation dependent on the foot-and-mouth disease virus (FMDV) internal ribosome entry site (IRES) occurs at two sites (Lab and Lb), 84 nucleotides (nt) apart. In vitro translation of an mRNA comprising the IRES and Lab-Lb intervening segment fused to a chloramphenicol acetyltransferase (CAT) reporter has been used to study the parameters influencing the ratio of the two products and the combined product yield as measures of relative initiation site usage and productive ribosome recruitment, respectively. With wild-type mRNA, ∼40% of initiation occurred at the Lab site, which was increased to 90% by optimization of its context, but decreased to 20% by mutations that reduced downstream secondary structure, with no change in recruitment in either case. Inserting 5 nt into the pyrimidine-rich tract located just upstream of the Lab site increased initiation at this site by 75% and ribosome recruitment by 50%. Mutating the Lab site to RCG or RUN codons decreased recruitment by 20 to 30% but stimulated Lb initiation by 20 to 40%. An antisense oligodeoxynucleotide annealing across the Lab site inhibited initiation at both sites. These and related results lead to the following conclusions. Recruitment by the wild-type IRES is limited by its short oligopyrimidine tract. At least 90% of internal ribosome entry occurs at the Lab AUG, but initiation at this site is restricted by its poor context, despite a counteracting effect of downstream secondary structure. Initiation at the Lb site is by ribosomes that access it by linear scanning from the original entry site, and not by an independent entry process.

Defining the roles and interactions of PTB.

PTB (polypyrimidine tract-binding protein) is an abundant and widely expressed RNA-binding protein with four RRM (RNA recognition motif) domains. PTB is involved in numerous post-transcriptional steps in gene expression in both the nucleus and cytoplasm, but has been best characterized as a regulatory repressor of some ASEs (alternative splicing events), and as an activator of translation driven by IRESs (internal ribosome entry segments). We have used a variety of approaches to characterize the activities of PTB and its molecular interactions with RNA substrates and protein partners. Using splice-sensitive microarrays we found that PTB acts not only as a splicing repressor but also as an activator, and that these two activities are determined by the location at which PTB binds relative to target exons. We have identified minimal splicing repressor and activator domains, and have determined high resolution structures of the second RRM domain of PTB binding to peptide motifs from the co-repressor protein Raver1. Using single-molecule techniques we have determined the stoichiometry of PTB binding to a regulated splicing substrate in whole nuclear extracts. Finally, we have used tethered hydroxyl radical probing to determine the locations on viral IRESs at which each of the four RRM domains bind. We are now combining tethered probing with single molecule analyses to gain a detailed understanding of how PTB interacts with pre-mRNA substrates to effect either repression or activation of splicing.

Mobility and aging: new directions for public health action.

Optimal mobility, defined as relative ease and freedom of movement in all of its forms, is central to healthy aging. Mobility is a significant consideration for research, practice, and policy in aging and public health. We examined the public health burdens of mobility disability, with a particular focus on leading public health interventions to enhance walking and driving, and the challenges and opportunities for public health action. We propose an integrated mobility agenda, which draws on the lived experience of older adults. New strategies for research, practice, and policy are needed to move beyond categorical promotion programs in walking and driving to establish a comprehensive program to enhance safe mobility in all its forms.