GWAS meta-analysis reveals key risk loci in essential tremor pathogenesis

Essential tremor (ET) is a prevalent neurological disorder with a largely unknown underlying biology. In this genome-wide association study meta-analysis, comprising 16,480 ET cases and 1,936,173 controls from seven datasets, we identify 12 sequence variants at 11 loci. Evaluating mRNA expression, splicing, plasma protein levels, and coding effects, we highlight seven putative causal genes at these loci, including CA3 and CPLX1. CA3 encodes Carbonic Anhydrase III and carbonic anhydrase inhibitors have been shown to decrease tremors. CPLX1, encoding Complexin-1, regulates neurotransmitter release. Through gene-set enrichment analysis, we identify a significant association with specific cell types, including dopaminergic and GABAergic neurons, as well as biological processes like Rho GTPase signaling. Genetic correlation analyses reveals a positive association between ET and Parkinson's disease, depression, and anxiety-related phenotypes. This research uncovers risk loci, enhancing our knowledge of the complex genetics of this common but poorly understood disorder, and highlights CA3 and CPLX1 as potential therapeutic targets.

The structural repertoire of Fusarium oxysporum f. sp. lycopersici effectors revealed by experimental and computational studies

Plant pathogens secrete proteins, known as effectors, that function in the apoplast or inside plant cells to promote virulence. Effector recognition by cell-surface or cytosolic receptors results in the activation of defence pathways and plant immunity. Despite their importance, our general understanding of fungal effector function and recognition by immunity receptors remains poor. One complication often associated with effectors is their high sequence diversity and lack of identifiable sequence motifs precluding prediction of structure or function. In recent years, several studies have demonstrated that fungal effectors can be grouped into structural classes, despite significant sequence variation and existence across taxonomic groups. Using protein X-ray crystallography, we identify a new structural class of effectors hidden within the secreted in xylem (SIX) effectors from Fusarium oxysporum f. sp. lycopersici (Fol). The recognised effectors Avr1 (SIX4) and Avr3 (SIX1) represent the founding members of the Fol dual-domain (FOLD) effector class, with members containing two distinct domains. Using AlphaFold2, we predicted the full SIX effector repertoire of Fol and show that SIX6 and SIX13 are also FOLD effectors, which we validated experimentally for SIX6. Based on structural prediction and comparisons, we show that FOLD effectors are present within three divisions of fungi and are expanded in pathogens and symbionts. Further structural comparisons demonstrate that Fol secretes effectors that adopt a limited number of structural folds during infection of tomato. This analysis also revealed a structural relationship between transcriptionally co-regulated effector pairs. We make use of the Avr1 structure to understand its recognition by the I receptor, which leads to disease resistance in tomato. This study represents an important advance in our understanding of Fol-tomato, and by extension plant-fungal interactions, which will assist in the development of novel control and engineering strategies to combat plant pathogens.

Effect of a Conical-PEP Mask on Exercise in Subjects With COPD

BACKGROUND

Dynamic hyperinflation (DH) is a major pathophysiology of COPD that is directly related to dyspnea and exercise intolerance. Positive expiratory pressure (PEP) might reduce DH and dyspnea during exercise, but at present, there is insufficient evidence to conclude whether it is beneficial for DH, dyspnea, and exercise capacity in COPD.

METHODS

A randomized crossover trial with concealed allocation was conducted in 37 moderate to very severe subjects with COPD (34 males, age 66.6 ± 7.4 y, FEV1% of predicted 56.3 ± 13.7). The experimental condition was conical-PEP breathing with a PEP of around 5 cm H2O during a spot marching exercise at a constant speed, inducing 71 ± 9% age-predicted maximum heart rate to symptom limit or 25 min. The control condition was usual breathing. Exercise endurance time and end-exercise symptoms were recorded. Inspiratory capacity (IC) was measured pre-exercise and immediately post exercise. Cardiopulmonary function and breathlessness were monitored throughout the test and after 10 min of recovery.

RESULTS

There were no complications or adverse effects during exercise with a conical-PEP mask. Conical-PEP showed longer exercise times than control (median 11.0 [interquartile range 7.7-17.0] min vs 8 [6.0-11.5] min, respectively, P < .001). Most stopped exercising because of breathlessness and leg fatigue. At the end of exercise, IC and breathlessness showed non-significant differences between the conditions, but breathlessness was significantly lower in conical-PEP (median 4 [1.5-5.0] than control 5 [3-6] on Borg scale at isotime for control [8 min]).

CONCLUSIONS

Breathing with a 5 cm H2O conical-PEP mask improved exercise time (median 27.1% [0.6-52.9]) in subjects with COPD. The improvement in exercise with the conical-PEP mask was associated with slower development of breathlessness, possibly due to delays in DH development.

A rust-fungus Nudix hydrolase effector decaps mRNA in vitro and interferes with plant immune pathways

To infect plants, pathogenic fungi secrete small proteins called effectors. Here, we describe the catalytic activity and potential virulence function of the Nudix hydrolase effector AvrM14 from the flax rust fungus (Melampsora lini). We completed extensive in vitro assays to characterise the enzymatic activity of the AvrM14 effector. Additionally, we used in planta transient expression of wild-type and catalytically dead AvrM14 versions followed by biochemical assays, phenotypic analysis and RNA sequencing to unravel how the catalytic activity of AvrM14 impacts plant immunity. AvrM14 is an extremely selective enzyme capable of removing the protective 5' cap from mRNA transcripts in vitro. Homodimerisation of AvrM14 promoted biologically relevant mRNA cap cleavage in vitro and this activity was conserved in related effectors from other Melampsora spp. In planta expression of wild-type AvrM14, but not the catalytically dead version, suppressed immune-related reactive oxygen species production, altered the abundance of some circadian-rhythm-associated mRNA transcripts and reduced the hypersensitive cell-death response triggered by the flax disease resistance protein M1. To date, the decapping of host mRNA as a virulence strategy has not been described beyond viruses. Our results indicate that some fungal pathogens produce Nudix hydrolase effectors with in vitro mRNA-decapping activity capable of interfering with plant immunity.

Individualised Estimation of Quality-adjusted Survival Benefit and Cost-effectiveness of Proton Beam Therapy in Intermediate-stage Hodgkin Lymphoma

AIMS

Radiotherapy for Hodgkin lymphoma leads to the irradiation of organs at risk (OAR), which may confer excess risks of late effects. Comparative dosimetry studies show that proton beam therapy (PBT) may reduce OAR irradiation compared with photon radiotherapy, but PBT is more expensive and treatment capacity is limited. The purpose of this study is to inform the appropriateness of PBT for intermediate-stage Hodgkin lymphoma (ISHL).

MATERIALS AND METHODS

A microsimulation model simulating the course of ISHL, background mortality and late effects was used to estimate comparative quality-adjusted life years (QALYs) lived and healthcare costs after consolidative pencil beam scanning PBT or volumetric modulated arc therapy (VMAT), both in deep-inspiration breath-hold. Outcomes were compared for 606 illustrative patients covering a spectrum of clinical presentations, varying by two age strata (20 and 40 years), both sexes, three smoking statuses (never, former and current) and 61 pairs of OAR radiation doses from a comparative planning study. Both undiscounted and discounted outcomes at 3.5% yearly discount were estimated. The maximum excess cost of PBT that might be considered cost-effective by the UK's National Institute for Health and Care Excellence was calculated.

RESULTS

OAR doses, smoking status and discount rate had large impacts on QALYs gained with PBT. Current smokers benefited the most, averaging 0.605 undiscounted QALYs (range -0.341 to 2.171) and 0.146 discounted QALYs (range -0.067 to 0.686), whereas never smokers benefited the least, averaging 0.074 undiscounted QALYs (range -0.196 to 0.491) and 0.017 discounted QALYs (range -0.030 to 0.086). For the gain in discounted QALYs to be considered cost-effective, PBT would have to cost at most £4812 more than VMAT for current smokers and £645 more for never smokers. This is below preliminary National Health Service cost estimates of PBT over photon radiotherapy.

CONCLUSION

In a UK setting, PBT for ISHL may not be considered cost-effective. However, the degree of unquantifiable uncertainty is substantial.

Genetic variants associated with syncope implicate neural and autonomic processes

AIMS

Syncope is a common and clinically challenging condition. In this study, the genetics of syncope were investigated to seek knowledge about its pathophysiology and prognostic implications.

METHODS AND RESULTS

This genome-wide association meta-analysis included 56 071 syncope cases and 890 790 controls from deCODE genetics (Iceland), UK Biobank (United Kingdom), and Copenhagen Hospital Biobank Cardiovascular Study/Danish Blood Donor Study (Denmark), with a follow-up assessment of variants in 22 412 cases and 286 003 controls from Intermountain (Utah, USA) and FinnGen (Finland). The study yielded 18 independent syncope variants, 17 of which were novel. One of the variants, p.Ser140Thr in PTPRN2, affected syncope only when maternally inherited. Another variant associated with a vasovagal reaction during blood donation and five others with heart rate and/or blood pressure regulation, with variable directions of effects. None of the 18 associations could be attributed to cardiovascular or other disorders. Annotation with regard to regulatory elements indicated that the syncope variants were preferentially located in neural-specific regulatory regions. Mendelian randomization analysis supported a causal effect of coronary artery disease on syncope. A polygenic score (PGS) for syncope captured genetic correlation with cardiovascular disorders, diabetes, depression, and shortened lifespan. However, a score based solely on the 18 syncope variants performed similarly to the PGS in detecting syncope risk but did not associate with other disorders.

CONCLUSION

The results demonstrate that syncope has a distinct genetic architecture that implicates neural regulatory processes and a complex relationship with heart rate and blood pressure regulation. A shared genetic background with poor cardiovascular health was observed, supporting the importance of a thorough assessment of individuals presenting with syncope.

Decrements of mobility and power in recreationally active septuagenarians is related to loss of force, but not slowing of the muscle: a 5-year longitudinal study

A lesser 6-min walk distance (6MWD) and timed up-and-go (TUG) in old compared with young adults was previously linked to slowing of muscle contractile properties. The purpose of the present study was to determine whether any further reductions in 6MWD and TUG over a 5-year period in septuagenarians are associated with further slowing of muscle contractile properties. We measured muscle function by a countermovement jump, isometric maximal knee extensor strength (MVC) on a dynamometer and quadriceps muscle size by magnetic resonance imaging (MRI) in 17 older women (71.1 ± 2.8 y) and 17 older men (71.3 ± 4.1y). Performance in TUG and 6MWD were reduced over the 5-year period, irrespective of sex (P < 0.001), and both were correlated with power at both baseline and follow-up (R ≥ 0.53; P ≤ 0.001). Jump take-off velocity (V_CMJ) was slower at follow-up (P < 0.01) and correlated with 6MWD and TUG at both baseline and follow-up in both sexes (R ≥ 0.54; P ≤ 0.001). However, the relationship between 'body mass: maximal muscle force ratio' with V_CMJ was not significantly changed, indicating that the lower V_CMJ was attributable to muscles working at a higher relative load, hence a lower part of the force-velocity relationship, due to a reduction in MVC (body mass had not changed significantly), rather than slowing of the muscle. The lower V_CMJ in women than men (P < 0.001) was likewise attributable to a lower MVC rather than slower contractile properties in women. In conclusion, the decrement in 6MWD and TUG in septuagenarians is due to a loss of muscle mass, rather than further loss of muscle quality.

Transcriptome Analysis of Fusarium–Tomato Interaction Based on an Updated Genome Annotation of Fusarium oxysporum f. sp. lycopersici Identifies Novel Effector Candidates That Suppress or Induce Cell Death in Nicotiana benthamiana

Fusarium oxysporum f. sp. lycopersici (Fol) causes vascular wilt disease in tomato. Upon colonization of the host, Fol secretes many small effector proteins into the xylem sap to facilitate infection. Besides known SIX (secreted in xylem) proteins, the identity of additional effectors that contribute to Fol pathogenicity remains largely unexplored. We performed a deep RNA-sequencing analysis of Fol race 2-infected tomato, used the sequence data to annotate a published genome assembly generated via PacBio SMRT sequencing of the Fol race 2 reference strain Fol4287, and analysed the resulting transcriptome to identify Fol effector candidates among the newly annotated genes. We examined the Fol-infection expression profiles of all 13 SIX genes present in Fol race 2 and identified 27 new candidate effector genes that were likewise significantly upregulated upon Fol infection. Using Agrobacterium-mediated transformation, we tested the ability of 22 of the new candidate effector genes to suppress or induce cell death in leaves of Nicotiana benthamiana. One effector candidate designated Fol-EC19, encoding a secreted guanyl-specific ribonuclease, was found to trigger cell death and two effector candidates designated Fol-EC14 and Fol-EC20, encoding a glucanase and a secreted trypsin, respectively, were identified that can suppress Bax-mediated cell death. Remarkably, Fol-EC14 and Fol-EC20 were also found to suppress I-2/Avr2- and I/Avr1-mediated cell death. Using the yeast secretion trap screening system, we showed that these three biologically-active effector candidates each contain a functional signal peptide for protein secretion. Our findings provide a basis for further understanding the virulence functions of Fol effectors.

Germline variants of ATG7 in familial cholangiocarcinoma alter autophagy and p62

Autophagy is a housekeeping mechanism tasked with eliminating misfolded proteins and damaged organelles to maintain cellular homeostasis. Autophagy deficiency results in increased oxidative stress, DNA damage and chronic cellular injury. Among the core genes in the autophagy machinery, ATG7 is required for autophagy initiation and autophagosome formation. Based on the analysis of an extended pedigree of familial cholangiocarcinoma, we determined that all affected family members had a novel germline mutation (c.2000C>T p.Arg659* (p.R659*)) in ATG7. Somatic deletions of ATG7 were identified in the tumors of affected individuals. We applied linked-read sequencing to one tumor sample and demonstrated that the ATG7 somatic deletion and germline mutation were located on distinct alleles, resulting in two hits to ATG7. From a parallel population genetic study, we identified a germline polymorphism of ATG7 (c.1591C>G p.Asp522Glu (p.D522E)) associated with increased risk of cholangiocarcinoma. To characterize the impact of these germline ATG7 variants on autophagy activity, we developed an ATG7-null cell line derived from the human bile duct. The mutant p.R659* ATG7 protein lacked the ability to lipidate its LC3 substrate, leading to complete loss of autophagy and increased p62 levels. Our findings indicate that germline ATG7 variants have the potential to impact autophagy function with implications for cholangiocarcinoma development.

Investigating the relationship between euthanasia and/or assisted suicide and rates of non-assisted suicide: systematic review

BACKGROUND

Euthanasia and assisted suicide (EAS) are practices that aim to alleviate the suffering of people with life-limiting illnesses, but are controversial. One area of debate is the relationship between EAS and suicide rates in the population, where there have been claims that availability of EAS will reduce the number of self-initiated deaths (EAS and suicide combined). Others claim that legislation for EAS makes it acceptable to end one's own life, a message at variance with that of suicide prevention campaigns.

AIMS

To examine the relationship between the introduction of EAS and rates of non-assisted suicide and self-initiated death.

METHOD

We conducted a systematic review to examine the association between EAS and rates of non-assisted suicide and of self-initiated death. We searched PubMed, Scopus, PsycINFO and Science Direct, until 20 December 2021. Studies that examined EAS and reported data on population-based suicide rates were included.

RESULTS

Six studies met the inclusion criteria; four reported increases in overall rates of self-initiated death and, in some cases, increased non-assisted suicide. This increase in non-assisted suicide was mostly non-significant when sociodemographic factors were controlled for. Studies from Switzerland and Oregon reported elevated rates of self-initiated death among older women, consistent with higher rates of depressive illnesses in this population.

CONCLUSIONS

The findings of this review do not support the hypothesis that introducing EAS reduces rates of non-assisted suicide. The disproportionate impact on older women indicates unmet suicide prevention needs in this population.

Informing radiotherapy decisions in stage I/IIa Hodgkin lymphoma: modeling life expectancy using radiation dosimetry

In recent randomized trials, omitting consolidative radiotherapy (RT) in early-stage Hodgkin lymphoma (ESHL) increased relapses. However, decades of follow-up are required to observe whether lower initial disease control is compensated by reduced risk of late effects. Extrapolation beyond trial follow-up is therefore necessary to inform current treatment decisions. To this end, we developed a microsimulation model to estimate lifetime quality-adjusted life years (QALYs) after combined modality treatment (CMT) or chemotherapy-alone for stage I/IIa ESHL. For CMT, the model included risks of breast and lung cancer, coronary heart disease, and ischemic stroke. Comparative outcomes were assessed for a clinically relevant range of example patients differing by age, sex, smoking status, and representative organs at risk (OAR) radiation doses informed by the RAPID trial. Analysis was performed with and without a 3.5% discount rate on future health. Smoking status had a large effect on optimal treatment choice. CMT was superior for nearly all never smoker example patients regardless of age, sex, and OAR doses. At a maximum, CMT produced a 1.095 (95% CI: 1.054-1.137) gain in undiscounted QALYs for a 20-year-old male never smoker with unilateral neck disease. In contrast, current smokers could substantially gain from chemotherapy-alone treatment. Again at a maximum, a 20-year-old male current smoker with bilateral neck and whole mediastinum involvement gained 3.500 (95% CI: 3.400 to 3.600) undiscounted QALYs with chemotherapy-alone treatment. Overall, CMT was more favorable the younger the patient, when future health discounting was included, and in never smokers.

Optimized Production of Disulfide-Bonded Fungal Effectors in Escherichia coli Using CyDisCo and FunCyDisCo Coexpression Approaches

Effectors are a key part of the arsenal of plant-pathogenic fungi and promote pathogen virulence and disease. Effectors typically lack sequence similarity to proteins with known functional domains and motifs, limiting our ability to predict their functions and understand how they are recognized by plant hosts. As a result, cross-disciplinary approaches involving structural biology and protein biochemistry are often required to decipher and better characterize effector function. These approaches are reliant on high yields of relatively pure protein, which often requires protein production using a heterologous expression system. For some effectors, establishing an efficient production system can be difficult, particularly those that require multiple disulfide bonds to achieve their naturally folded structure. Here, we describe the use of a coexpression system within the heterologous host Escherichia coli, termed CyDisCo (cytoplasmic disulfide bond formation in E. coli) to produce disulfide bonded fungal effectors. We demonstrate that CyDisCo and a naturalized coexpression approach termed FunCyDisCo (Fungi CyDisCo) can significantly improve the production yields of numerous disulfide-bonded effectors from diverse fungal pathogens. The ability to produce large quantities of functional recombinant protein has facilitated functional studies and crystallization of several of these reported fungal effectors. We suggest this approach could be broadly useful in the investigation of the function and recognition of a broad range of disulfide bond-containing effectors.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

The impact of non-pharmacological therapies on cardiovascular outcomes in patients with refractory angina: a systematic review and meta-analysis of randomized controlled trials

 

Despite advances in revascularization techniques and optimal medical management, refractory angina (RFA) represents an essential group of patients where progress has stalled, and in which therapeutic approaches remain uncertain.

Numerous randomized control trials have reported clinical outcomes on a variety of treatments but to date no direct outcome comparison has been made. Our aim is to investigate and compare the outcomes of these different non-pharmacological technologies in RFA, centring on major adverse cardiac events and all-cause mortality.

We performed a systematic review and meta-analysis of randomized controlled trials using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. A comprehensive search was performed of PubMed, EMBASE (Excerpta Medica database),Cochrane, ClinicalTrials.gov, Google Scholar databases of randomized controlled trials, and scientific session abstracts. Studies were deemed eligible if they met the following criteria: (1) full-length publications in peer-reviewed journals; (2) evaluated non-pharmacological therapies use in patients with no further revascularization options while on optimal medical treatment; (3) patients had ongoing angina, Canadian Cardiovascular Society class II–IV; and (4) included a placebo/control arm. We calculated risk ratios for all-cause mortality, combined MACE events. We assessed heterogeneity using χ2 and I2 tests.

We analysed 3292 citations with 51 randomized control trials testing 9 therapies including angiogenic proteins, stem-cell therapy, lipoprotein apheresis, coronary sinus reducer, spinal cord stimulator, percutaneous laser revascularization, shock-wave therapy, transmyocardial laser revascularization and enhanced external counter pulsation all meeting the inclusion criteria (table 1). Our analysis identified stem cell therapy as the only therapy with a reduction in all-cause mortality (Odds ratio, 0.45; CI, 0.21–1.00) (figure 1). A corresponding reduction in major adverse cardiac events (MACE) was also seen with stem cell therapy (OR 0.48: CI 0.30–0.75) alongside patients who received angiogenic proteins (OR 0.72: CI 0.55–0.93) and cardiac shockwave therapy (OR, 0.21: CI 0.10–0.46) Improvements in secondary measures of angina symptoms or frequency were seen with stem cell therapy, angiogenic proteins, coronary sinus reducer, spinal cord stimulator, shock-wave therapy, transmyocardial laser revascularization and enhanced external counterpulsation.

This is the largest meta-analysis comparing outcomes of novel technologies used in refractory angina. This suggests that stem cell therapy is the only non-pharmacological therapy for RFA associated with a reduction in mortality, MACE and anginal symptoms. We propose further larger randomized control trials, to support these findings.

Funding Acknowledgement

Type of funding sources: None. Table 1. Randomized control trials and outcomesFigure 1. All-cause mortality forest plot

A genome-wide meta-analysis uncovers six sequence variants conferring risk of vertigo

Vertigo is the leading symptom of vestibular disorders and a major risk factor for falls. In a genome-wide association study of vertigo (Ncases = 48,072, Ncontrols = 894,541), we uncovered an association with six common sequence variants in individuals of European ancestry, including missense variants in ZNF91, OTOG, OTOGL, and TECTA, and a cis-eQTL for ARMC9. The association of variants in ZNF91, OTOGL, and OTOP1 was driven by an association with benign paroxysmal positional vertigo. Using previous reports of sequence variants associating with age-related hearing impairment and motion sickness, we found eight additional variants that associate with vertigo. Although disorders of the auditory and the vestibular system may co-occur, none of the six genome-wide significant vertigo variants were associated with hearing loss and only one was associated with age-related hearing impairment. Our results uncovered sequence variants associating with vertigo in a genome-wide association study and implicated genes with known roles in inner ear development, maintenance, and disease.

The crystal structure of SnTox3 from the necrotrophic fungus Parastagonospora nodorum reveals a unique effector fold and provides insight into Snn3 recognition and pro-domain protease processing of fungal effectors

Plant pathogens cause disease through secreted effector proteins, which act to promote infection. Typically, the sequences of effectors provide little functional information and further targeted experimentation is required. Here, we utilized a structure/function approach to study SnTox3, an effector from the necrotrophic fungal pathogen Parastagonospora nodorum, which causes cell death in wheat-lines carrying the sensitivity gene Snn3. We developed a workflow for the production of SnTox3 in a heterologous host that enabled crystal structure determination and functional studies. We show this approach can be successfully applied to study effectors from other pathogenic fungi. The β-barrel fold of SnTox3 is a novel fold among fungal effectors. Structure-guided mutagenesis enabled the identification of residues required for Snn3 recognition. SnTox3 is a pre-pro-protein, and the pro-domain of SnTox3 can be cleaved in vitro by the protease Kex2. Complementing this, an in silico study uncovered the prevalence of a conserved motif (LxxR) in an expanded set of putative pro-domain-containing fungal effectors, some of which can be cleaved by Kex2 in vitro. Our in vitro and in silico study suggests that Kex2-processed pro-domain (designated here as K2PP) effectors are common in fungi and this may have broad implications for the approaches used to study their functions.

The crystal structure of SnTox3 from the necrotrophic fungus Parastagonospora nodorum reveals a unique effector fold and provides insight into Snn3 recognition and pro-domain protease processing of fungal effectors

Plant pathogens cause disease through secreted effector proteins, which act to promote infection. Typically, the sequences of effectors provide little functional information and further targeted experimentation is required. Here, we utilized a structure/function approach to study SnTox3, an effector from the necrotrophic fungal pathogen Parastagonospora nodorum, which causes cell death in wheat-lines carrying the sensitivity gene Snn3. We developed a workflow for the production of SnTox3 in a heterologous host that enabled crystal structure determination and functional studies. We show this approach can be successfully applied to study effectors from other pathogenic fungi. The β-barrel fold of SnTox3 is a novel fold among fungal effectors. Structure-guided mutagenesis enabled the identification of residues required for Snn3 recognition. SnTox3 is a pre-pro-protein, and the pro-domain of SnTox3 can be cleaved in vitro by the protease Kex2. Complementing this, an in silico study uncovered the prevalence of a conserved motif (LxxR) in an expanded set of putative pro-domain-containing fungal effectors, some of which can be cleaved by Kex2 in vitro. Our in vitro and in silico study suggests that Kex2-processed pro-domain (designated here as K2PP) effectors are common in fungi and this may have broad implications for the approaches used to study their functions.

Did the Pope ban blood transfusion in 1678?

This paper concerns an alleged event in the history of haematology that disrupts the otherwise positive narrative of papal encouragement for blood transfusion. It is frequently stated, in popular websites and in the scholarly literature, that when blood transfusion was first developed it was banned by the Pope. However, careful analysis of the sources cited shows this claim to be without historical foundation. There was never any papal prohibition of blood transfusion. It is a myth that needs to be dispelled if the full extent of the Catholic Church's support for blood and organ donation is to be appreciated.

Response of Knee Extensor Muscle-Tendon Unit Stiffness to Unaccustomed and Repeated High-Volume Eccentric Exercise

The purposes of this study were to investigate the muscle-tendon unit stiffness response and to compare the stiffness with those of other indirect markers induced by two bouts of unaccustomed eccentric exercise. Eleven untrained men performed two bouts of 200 maximal eccentric contractions of the right quadriceps 4 weeks apart. Changes in stiffness, pain evoked by stretching and pressure, plasma creatine kinase (CK) activity, and muscle thickness were followed for 7 days after each bout. Stiffness and pain peaked immediately and 1 day after the first exercise bout, whereas CK and thickness were highest 4 and 7 days after the first exercise bout, respectively (p < 0.05 for all). Muscular pain, thickness, and stiffness responses were lower by 53.3%, 99%, and 11.6%, respectively, after the repeated bout compared to after the first bout (p < 0.05 for all), while CK activity response did not differ significantly between bouts. High responders for an increase in muscle-tendon unit stiffness showed a repeated-bout effect for stiffness, pain, and CK activity (by 29%, 65%, and 98%, p < 0.05 for all), but the repeated-bout effect was not that clear in low responders. These findings suggest that a repeated eccentric exercise bout effect on stiffness in quadriceps is mostly not associated with muscle pain and CK activity, but there are large individual differences.

Stair Gait in Older Adults Worsens With Smaller Step Treads and When Transitioning Between Level and Stair Walking

Older people have an increased risk of falling during locomotion, with falls on stairs being particularly common and dangerous. Step going (i.e., the horizontal distance between two consecutive step edges) defines the base of support available for foot placement on stairs, as with smaller going, the user's ability to balance on the steps may become problematic. Here we quantified how stair negotiation in older participants changes between four goings (175, 225, 275, and 325 mm) and compared stair negotiation with and without a walking approach. Twenty-one younger (29 ± 6 years) and 20 older (74 ± 4 years) participants negotiated a 7-step experimental stair. Motion capture and step-embedded force platform data were collected. Handrail use was also monitored. From the motion capture data, body velocity, trunk orientation, foot clearance and foot overhang were quantified. For all participants, as stair going decreased, gait velocity (ascent p_A = 0.033, descent p_D = 0.003) and horizontal step clearance decreased (p_A = 0.001), while trunk rotation (p_D = 0.002) and foot overhang increased (p_A,D < 0.001). Compared to the younger group, older participants used the handrail more, were slower across all conditions (p_A < 0.001, p_D = 0.001) and their foot clearance tended to be smaller. With a walking approach, the older group (Group x Start interaction) showed a larger trunk rotation (p_A = 0.011, p_D = 0.015), and smaller lead foot horizontal (p_A = 0.046) and vertical clearances (p_D = 0.039) compared to the younger group. A regression analysis to determine the predictors of foot clearance and amount of overhang showed that physical activity was a common predictor for both age groups. In addition, for the older group, medications and fear of falling were found to predict stair performance for most goings, while sway during single-legged standing was the most common predictor for the younger group. Older participants adapted to smaller goings by using the handrails and reducing gait velocity. The predictors of performance suggest that motor and fall risk assessment is complex and multifactorial. The results shown here are consistent with the recommendation that larger going and pausing before negotiating stairs may improve stair safety, especially for older users.

Use of enhanced stent visualisation compared to angiography alone to guide percutaneous coronary intervention

OBJECTIVE

We aimed to assess the use of enhanced stent visualisation (ESV) on outcomes, after PCI with overlapping stents, specifically using CLEARstent technology.

BACKGROUND

Stent underexpansion and overlap are both significant risk factors for restenosis and stent thrombosis. Enhanced stent visualisation (e.g. CLEARstent) systems could provide important data to reduce under-expansion and stent overlap.

METHODS

This was a cohort study based on this institution's percutaneous coronary intervention (PCI) registry. A total of 2614 patients who had PCI for stable angina or acute coronary syndromes (ACS, excluding cardiogenic shock) with overlapping 2nd generation drug eluting stents (DES) in the same vessel between May 2015 and January 2018 were included in the analysis. Patients were divided into ESV (n = 1354) and no ESV guided intervention (n = 1260). The primary end-point was major adverse cardiovascular events (MACE: target vessel revascularisation, target vessel myocardial infarction and all-cause mortality) recorded at a median follow up of 2.4 years.

RESULTS

Groups were comparable for patient characteristics (age, diabetes mellitus, ACS presentation). A significant difference in MACE was observed between patients who underwent ESV-guided PCI (9.5%) compared with patients who underwent Standard PCI (14.4%, p = .018). This difference was mainly driven by reduced rates of target vessel revascularisation and recurrent myocardial infarction. Overall this difference persisted after multivariate Cox analysis (HR 0.86, 95% CI: 0.73-0.98) and propensity matching (HR = 0.88, 95% CI: 0.69-0.99).

CONCLUSION

We suggest that routine clinical use of ESV technology during PCI can be useful, and is associated with better medium-term angiographic and clinical outcomes. Further study is required to build on this promising signal.

The Aspergillus nidulans IQGAP orthologue SepG is required for constriction of the contractile actomyosin ring

In this research we report that the sepG1 mutation in Aspergillus nidulans resides in gene AN9463, which is predicted to encode an IQGAP orthologue. The genetic lesion is predicted to result in a G-to-R substitution at residue 1637 of the 1737-residue protein in a highly conserved region of the RasGAP-C-terminal (RGCT) domain. When grown at restrictive temperature, strains expressing the sepG^G1637R (sepG1) allele are aseptate, with reduced colony growth and aberrantly formed conidiophores. The aseptate condition can be replicated by deletion of AN9463 or by downregulating its expression via introduced promoters. The mutation does not prevent assembly of a cortical contractile actomyosin ring (CAR) at putative septation sites, but tight compaction of the rings is impaired and the rings fail to constrict. Both GFP::SepG wild type and the GFP-tagged product of the sepG1 allele localize to the CAR at both permissive and restrictive temperatures. Downregulation of myoB (encoding the A. nidulans type-II myosin heavy chain) does not prevent formation of SepG rings at septation sites, but filamentous actin is required for CAR localization of SepG and MyoB. We identify fourteen probable IQ-motifs (EF-hand protein binding sites) in the predicted SepG sequence. Two of the A. nidulans EF-hand proteins, myosin essential light chain (AnCdc4) and myosin regulatory light chain (MrlC), colocalize with SepG and MyoB at all stages of CAR formation and constriction. However, calmodulin (CamA) appears at septation sites only after the CAR has become fully compacted. When expression of sepG is downregulated, leaving MyoB as the sole IQ-motif protein in the pre-compaction CAR, both MrlC and AnCdc4 continue to associate with the forming CAR. When myoB expression is downregulated, leaving SepG as the sole IQ-motif protein in the CAR, AnCdc4 association with the forming CAR continues but MrlC fails to associate. This supports a model in which the IQ motifs of MyoB bind both MrlC and AnCdc4, while the IQ motifs of SepG bind only AnCdc4. Downregulation of either mrlC or Ancdc4 results in an aseptate phenotype, but has no effect on association of either SepG or MyoB with the CAR.

Are Force Enhancement after Stretch and Muscle Fatigue Due to Effects of Elevated Inorganic Phosphate and Low Calcium on Cross Bridge Kinetics?

Background and Objectives: Muscle fatigue is characterised by (1) loss of force, (2) decreased maximal shortening velocity and (3) a greater resistance to stretch that could be due to reduced intracellular Ca²⁺ and increased Pi, which alter cross bridge kinetics. Materials and Methods: To investigate this, we used (1) 2,3-butanedione monoxime (BDM), believed to increase the proportion of attached but non-force-generating cross bridges; (2) Pi that increases the proportion of attached cross bridges, but with Pi still attached; and (3) reduced activating Ca²⁺. We used permeabilised rat soleus fibres, activated with pCa 4.5 at 15 °C. Results: The addition of 1 mM BDM or 15 mM Pi, or the lowering of the Ca²⁺ to pCa 5.5, all reduced the isometric force by around 50%. Stiffness decreased in proportion to isometric force when the fibres were activated at pCa 5.5, but was well maintained in the presence of Pi and BDM. Force enhancement after a stretch increased with the length of stretch and Pi, suggesting a role for titin. Maximum shortening velocity was reduced by about 50% in the presence of BDM and pCa 5.5, but was slightly increased by Pi. Neither decreasing Ca²⁺ nor increasing Pi alone mimicked the effects of fatigue on muscle contractile characteristics entirely. Only BDM elicited a decrease of force and slowing with maintained stiffness, similar to the situation in fatigued muscle. Conclusions: This suggests that in fatigue, there is an accumulation of attached but low-force cross bridges that cannot be the result of the combined action of reduced Ca²⁺ or increased Pi alone, but is probably due to a combination of factors that change during fatigue.

Five-year longitudinal changes in thigh muscle mass of septuagenarian men and women assessed with DXA and MRI

Magnetic resonance imaging (MRI) and dual-energy X-ray absorptiometry (DXA) were used to assess changes in thigh lean mass in septuagenarian men and women during a 5-year longitudinal study. Twenty-four older individuals participated in the study (10 men: 71.6 ± 4.1 years; 14 women: 71.3 ± 3.2 years at baseline). Thigh MRI and whole-body DXA scans were used to estimate changes in thigh lean mass. Both MRI and DXA showed that thigh lean mass was reduced by approximately 5% (P = 0.001) over the 5-year period in both men and women. The percentage loss of muscle mass determined with MRI and DXA showed moderate correlation (R² = 0.466; P < 0.001). Bland–Altman analysis showed that the average change over 5 years of follow-up measured by DXA was only 0.18% greater than MRI, where the limits of agreement between DXA and MRI were ± 10.4%. Baseline thigh lean mass did not predict the percentage loss of thigh lean mass over the 5-year period (R² = 0.003; P = 0.397), but a higher baseline body fat percentage was associated with a larger loss of thigh muscle mass in men (R² = 0.677; P < 0.003) but not in women (R² = 0.073; P < 0.176). In conclusion, (1) DXA and MRI showed a similar percentage loss of muscle mass over a 5-year period in septuagenarian men and women that (2) was independent of baseline muscle mass, but (3) increased with higher baseline body fat percentage in men.

Low frequency fatigue and changes in muscle fascicle length following eccentric exercise of the knee extensors

NEW FINDING

What is the central question of this study? Does low frequency muscle fatigue indicate a failure of excitation-contraction coupling after eccentric exercise, or is it simply due to a change in muscle length? What is the main finding and its importance? The low to high frequency muscle fatigue ratio was relatively insensitive to changes in muscle length, and any changes in length following eccentric exercise were far too small to account for the high degree of low frequency fatigue. The results strengthen the suggestion that the early loss of force following eccentric exercise is due to a deficit of excitation-contraction coupling.

ABSTRACT

Development of long lasting fatigue (low frequency fatigue; LFF), assessed as the ratio of forces at 20 and 100 Hz stimulation, suggests the early phase of muscle damage caused by eccentric exercise is due to a deficit of excitation-contraction coupling. However, this could be caused by a change of muscle length. Eleven men (21.3 ± 2.0 years) performed 200 maximum eccentric knee extensions (30-110 deg flexion). Force generated by 20 and 100 Hz stimulation and maximum isometric force (MIF) were determined at knee angles 50, 70 and 90 deg before and immediately after the exercise. Vastus lateralis fascicle length (FL) was measured by ultrasound of resting and contracting muscle. Peak MIF (829 ± 119 N) was at 70 deg knee flexion, falling to 486 ± 180 N (P < 0.001) after exercise, but with no change in optimum angle. FLs at rest were unaffected by eccentric exercise, but during contraction they were on average 8.8% (95% CI: 4.1, 13.5%, P = 0.002) longer after exercise. Before exercise, the 20/100 ratio increased with muscle length, from 0.69 ± 0.09 at 50 deg, 0.72 ± 0.05 at 70 deg and 0.80 ± 0.08 at knee angle 90 deg (P < 0.001). After eccentric exercise the 20/100 ratio was reduced to 0.29 ± 0.08 at 50 deg, 0.27 ± 0.04 at 70 deg and 0.34 ± 0.04 at 90 deg (P < 0.001). The 20/100 ratio was relatively insensitive to changes in muscle length and the decrease following eccentric exercise was far greater than might be caused by any changes in muscle length after eccentric exercise. The results show that LFF following eccentric exercise is not due to change in muscle length and strengthen the suggestion that it represents a deficit in excitation-contraction coupling.

Concurrent cisplatin or cetuximab with radiotherapy for HPV-positive oropharyngeal cancer: Medical resource use, costs, and quality-adjusted survival from the De-ESCALaTE HPV trial

BACKGROUND

The De-ESCALaTE HPV trial confirmed the dominance of cisplatin over cetuximab for tumour control in patients with human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC). Here, we present the analysis of health-related quality of life (HRQoL), resource use, and health care costs in the trial, as well as complete 2-year survival and recurrence.

MATERIALS AND METHODS

Resource use and HRQoL data were collected at intervals from the baseline to 24 months post treatment (PT). Health care costs were estimated using UK-based unit costs. Missing data were imputed. Differences in mean EQ-5D-5L utility index and adjusted cumulative quality-adjusted life years (QALYs) were compared using the Wilcoxon signed-rank test and linear regression, respectively. Mean resource usage and costs were compared through two-sample t-tests.

RESULTS

334 patients were randomised to cisplatin (n = 166) or cetuximab (n = 168). Two-year overall survival (97·5% vs 90·0%, HR: 3.268 [95% CI 1·451 to 7·359], p = 0·0251) and recurrence rates (6·4% vs 16·0%, HR: 2·67 [1·38 to 5·15]; p = 0·0024) favoured cisplatin. No significant differences in EQ-5D-5L utility scores were detected at any time point. At 24 months PT, mean difference was 0·107 QALYs in favour of cisplatin (95% CI: 0·186 to 0·029, p = 0·007) driven by the mortality difference. Health care costs were similar across all categories except the procurement cost and delivery of the systemic agent, with cetuximab significantly more expensive than cisplatin (£7779 [P < 0.001]). Consequently, total costs at 24 months PT averaged £13517 (SE: £345) per patient for cisplatin and £21064 (SE: £400) for cetuximab (mean difference £7547 [95% CI: £6512 to £8582]).

CONCLUSIONS

Cisplatin chemoradiotherapy provided more QALYs and was less costly than cetuximab bioradiotherapy, remaining standard of care for nonsurgical treatment of HPV-positive OPSCC.

A systematic review of health economic evaluations of proton beam therapy for adult cancer: Appraising methodology and quality

BACKGROUND AND PURPOSE

With high treatment costs and limited capacity, decisions on which adult patients to treat with proton beam therapy (PBT) must be based on the relative value compared to the current standard of care. Cost-utility analyses (CUAs) are the gold-standard method for doing this. We aimed to appraise the methodology and quality of CUAs in this area.

MATERIALS AND METHODS

We performed a systematic review of the literature to identify CUA studies of PBT in adult disease using MEDLINE, EMBASE, EconLIT, NHS Economic Evaluation Database (NHS EED), Web of Science, and the Tufts Medical Center Cost-Effectiveness Analysis Registry from 1st January 2010 up to 6th June 2018. General characteristics, information relating to modelling approaches, and methodological quality were extracted and synthesized narratively.

RESULTS

Seven PBT CUA studies in adult disease were identified. Without randomised controlled trials to inform the comparative effectiveness of PBT, studies used either results from one-armed studies, or dose-response models derived from radiobiological and epidemiological studies of PBT. Costing methods varied widely. The assessment of model quality highlighted a lack of transparency in the identification of model parameters, and absence of external validation of model outcomes. Furthermore, appropriate assessment of uncertainty was often deficient.

CONCLUSION

In order to foster credibility, future CUA studies must be more systematic in their approach to evidence synthesis and expansive in their consideration of uncertainties in light of the lack of clinical evidence.

Flax rust infection transcriptomics reveals a transcriptional profile that may be indicative for rust Avr genes

Secreted effectors of fungal pathogens are essential elements for disease development. However, lack of sequence conservation among identified effectors has long been a problem for predicting effector complements in fungi. Here we have explored the expression characteristics of avirulence (Avr) genes and candidate effectors of the flax rust fungus, Melampsora lini. We performed transcriptome sequencing and real-time quantitative PCR (qPCR) on RNA extracted from ungerminated spores, germinated spores, isolated haustoria and flax seedlings inoculated with M. lini isolate CH5 during plant infection. Genes encoding two categories of M. lini proteins, namely Avr proteins and plant cell wall degrading enzymes (CWDEs), were investigated in detail. Analysis of the expression profiles of 623 genes encoding predicted secreted proteins in the M. lini transcriptome shows that the six known Avr genes (i.e. AvrM (avrM), AvrM14, AvrL2, AvrL567, AvrP123 (AvrP) and AvrP4) fall within a group of 64 similarly expressed genes that are induced in planta and show a peak of expression early in infection with a subsequent decline towards sporulation. Other genes within this group include two paralogues of AvrL2, an AvrL567 virulence allele, and a number of genes encoding putative effector proteins. By contrast, M. lini genes encoding CWDEs fall into different expression clusters with their distribution often unrelated to their catalytic activity or substrate targets. These results suggest that synthesis of M. lini Avr proteins may be regulated in a coordinated fashion and that the expression profiling-based analysis has significant predictive power for the identification of candidate Avr genes.

P2720Diagnostic accuracy of Quantitative Flow Ratio (QFR) and Vessel Fractional Flow Reserve (vFFR) compared to Fractional Flow Reserve (FFR) based on 7.5 frames/second coronary angiography

Background

Fractional flow reserve (FFR) is the gold standard for the physiological assessment of intermediate coronary artery lesions. Recently, several novel methods for computation of FFR based on 3-dimensional quantitative coronary angiography have been developed. These techniques allow analyses to be performed retrospectively and do not require induction of hyperaemia. The development and validation of these techniques are based on good quality coronary angiography with high frames per second (15 fps) acquisition. The diagnostic accuracy of Quantitative Flow Ratio (QFR) and Vessel Fractional Flow Reserve (vFFR) in real world “radiation-save mode” coronary angiography has not been studied.

Purpose

To validate the accuracy of QFR and vFFR compared to FFR based on a series of coronary angiography acquired at 7.5 fps.

Methods

We retrospectively analyzed 134 vessels (102 patients) with intermediate coronary artery stenosis (30–90%) in whom an FFR measurement had been performed. All the coronary angiography were acquired at 7.5 fps. 33 vessels (20 patients) were excluded from the study due to unsuitable coronary anatomy, invalid FFR measurements, poor image quality and lack of 2 projections ≥25° apart. A total of 101 vessels (82 patients) were included in the final analysis. Contrast-QFR (cQFR), fixed-QFR (fQFR) and vFFR analysis were performed in these vessels by two independent trained experts blinded to the FFR readings. FFR measurements at hyperaemic steady state was taken as the gold standard reference.

Results

Good intra- and inter-observer reliability was noted for fQFR, cQFR and vFFR analysis (intra-observer mean difference for fQFR: 0.016±0.060, p=0.066; cQFR: 0.009±0.053, p=0.230; vFFR: 0.008±0.040, p=0.175; inter-observer mean difference for fQFR: 0.001±0.036, p=0.847; cQFR: −0.001±0.049; p=0.910, vFFR: −0.005±0.037, p=0.393). fQFR and cQFR showed good correlation with FFR (r=0.694, p<0.001 and r=0.674, p<0.001, respectively) while vFFR showed moderate correlation with FFR (r=0.388, p<0.001). Similarly, fQFR and cQFR showed good accuracy for the detection of functionally significant coronary stenosis (fQFR AUC 0.882 (95% CI 0.803–0.938) and cQFR AUC 0.886 (95% CI 0.807–0.940)) while vFFR showed moderate accuracy with AUC 0.719 (95% CI 0.621–0.804). For identifying functionally significant stenosis (FFR ≤0.80), the overall diagnostic accuracy were 81.2%, 85.2%, 75.3% for fQFR, cQFR and vFFR, repectively. The sensitivity and specificity were 72.7%, 89.9% (fQFR); 83.5%, 31.8% (cQFR) and 68.2%, 87.3% (vFFR).

Conclusion

Functional assessment of intermediate coronary stenosis based on 7.5 fps angiography-derived computational modelling is feasible. Our study shows that fQFR and cQFR have a better diagnostic accuracy for detecting functionally significant coronary stenosis compared to vFFR. At the lower radiation-save mode 7.5 fps angiography, cQFR does not appear to provide additional diagnostic accuracy compared to fQFR.

P6426The use of direct oral anti-coagulations (DOACs) compared to vitamin k antagonist in patients with left ventricular thrombus after acute myocardial infarction

Aim

Current guidelines recommend the use of Vitamin K Antagonist (VKA) for up to 3–6 months for the treatment of LV thrombus post- acute myocardial infarction (AMI). However based on evidence supporting the non-inferiority and potential superiority of Direct Oral Anti-Coagulation's (DOAC) compared to VKA for other indications such as atrial fibrillation, DOACs are being increasingly used off licence for the treatment of left ventricular (LV) thrombus post AMI. In this study we investigated the effect of DOACs compared to VKA on LV thrombus resolution and their safety profile in patients presenting with AMI.

Methods and results

This was a prospective observational study of 2,328 consecutive patients undergoing Percutaneous Coronary Intervention (PCI) for AMI between 2015- 2018, at a UK cardiac centre. Patients' details were collected from the hospital electronic database. The primary end-point was the rate of resolution of LV thrombus with bleeding rates as a secondary outcome.

Left ventricular (LV) thrombus was diagnosed by echocardiography, or cardiac magnetic resonance imaging in 98 (5.1%) patients. Sixty patients (61.2%) were started on VKA and 38 patients (38.8%) on DOAC therapy (Rivaroxaban: 57.9%, Apixaban, 36.8% and Edoxaban: 5.3%). Both groups were well matched in terms of baseline characteristics including age, previous cardiac history (previous MI, PCI, CABG), and cardiovascular risk factors (Hypertension, Diabetes, Hypercholesterolaemia).

Over the follow up period (median 1.8 years), overall rates of LV thrombus resolution were 86%. There was greater and earlier LV thrombus resolution in the DOAC group compared to patients treated with warfarin (75% vs 53%, p=0.0018, at 1 year), which persisted after adjusting for baseline variables (OR 1.8 95% CI 1.2–2.9). Major bleeding such as intracranial bleed, major GI bleed and bleed requiring hospital admission were lower in DOAC group, compared with VKA group (0% vs 5%, p=0.030) with no difference in rates of systemic thromboembolism (p=0.388).

Conclusion

This data suggests improved thrombus resolution in post ACS LV thrombosis in patient treated with DOACs compared to vitamin K antagonists. This improvement in thrombus resolution was accompanied with a better safety profile for the DOAC patients' vs VKA treated patients. This supports the need for randomised controlled trials to confirm this observational data.

Acknowledgement/Funding

None

P2671The addition of admission lactate to the CREST risk score to determine prognosis in out of hospital cardiac arrest: the C-AREST score

Introduction

There has been an increasing focus on the development of scoring systems for patients admitted following resuscitation from out-of-hospital cardiac arrest (OHCA) to determine both prognosis and short-term management. One such system, the CREST score, has been shown to predict circulatory aetiology death in patients without ST-elevation myocardial infarction, however with an increasing number of OHCAs seen, general scoring systems to predict outcome in OHCA would be helpful.

Aims

We sought to determine whether the addition of an admission lactate ≥8 mmol/l to the existing CREST score was able to better predict in-hospital mortality in patients admitted with OHCA.

Methods and results

We retrospectively analysed the data of 500 patients admitted with an OHCA of presumed cardiac origin to our tertiary cardiac centre between June 2014 and Oct 2018. Mean age was 62.6y (±14.7), 379 (76%) were male and 250 (50%) were Caucasian. 313 (62.6%) were admitted with ST elevation myocardial infarction or equivalent. 48.6% (243/500) of patients died in hospital and of those that survived, 20.2% (52/257) were left with hypoxic brain injury (CPC score 3–4).

When analysed independently, all individual factors other than history of Coronary artery disease (OR 1.47, p=0.084) significantly predicted in-hospital mortality: Admission lactate ≥8 mmol/l (OR 6.78, p<0.0001), non-shockable Rhythm (OR 10.9, p<0.0001), Ejection fraction <30% (OR 5.84, p<0.0001), Shock at presentation (OR 5.49, p<0.0001) and ischaemic Time >25 minutes (OR 12.8, p<0.0001).

When each factor was assigned one point and totalled, both increasing CREST and C-AREST scores were associated with increasing in-hospital mortality: CREST (0–5 points): 4.3%, 30.5%, 41.5%, 85.6%, 95.2%, 100% vs C-AREST (0–6 points): 9.1%, 28.3%, 41.9%, 62.8%, 97.6%, 96.4%, 100%. When analysed with stepwise logistic regression, the addition of admission lactate ≥8 mmol/l to the model improved the prediction of in-hospital mortality: CREST (40.8% of variance explained) vs C-AREST (43.3%), with admission lactate remaining an independently significant predictor (OR 3.67, p=0.002).

Conclusion

We describe a novel modification to the previously described CREST scoring system for OHCA: the C-AREST score. The addition of admission lactate ≥8 mmol/l may have a role in differentiating those in intermediate risk categories (score between 2 and 3) where the predicted in hospital mortality would otherwise vary greatly. Given the relative ease of obtaining admission lactate, this scoring system may further improve stratification of patients who may or may not benefit from invasive management.

P6516The association between prior coronary artery bypass graft surgery and outcome after percutaneous coronary intervention (PCI): an observational study of 123,780 patients

Background

Limited information exists regarding procedural success and clinical outcomes in patients with previous CABG undergoing percutaneous coronary intervention (PCI). We sought to compare outcomes in patients undergoing PCI with or without previous coronary artery bypass grafts (CABG).

Methods

This was an observational cohort study of 123,780 consecutive PCI procedures from the Pan-London (United Kingdom) PCI registry, from January 2005 to December 2015. The primary end-point was all-cause mortality at a median follow-up of 3.0 years (interquartile range 1.2–4.6 years).

Results

12,641 (10.2%) patients had a history of previous CABG, of whom 29.3% (n=3,703) underwent PCI to native vessels and 70.7% (n=8,938) to bypass grafts. There were significant differences in the demographic, clinical, and procedural characteristics of these groups. The risk of mortality during follow-up was significantly higher in patients with prior CABG (23.2%) (p=0.0005) compared to patients with no history of prior CABG (12.1%) and was seen for patients who underwent either native vessel (20.1%) or bypass graft PCI (24.2%, p<0.0001). However, after adjustment for baseline characteristics, there was no significant difference in outcomes seen between the groups when PCI was performed in native vessels in patients with previous CABG (HR 1.02, 95% CI 0.77–1.34; P=0.89) but a significant increase in mortality among patients with PCI to bypass grafts (HR 1.33 95% CI 1.03–1.71, P=0.026). This was seen after multivariate adjustment and propensity matching.

Figure 1. Kaplan-Meier Curves

Conclusion

Patients with prior CABG are older, with a greater comorbid burden and more complex procedural characteristics, but after adjustment for these differences clinical outcomes are similar to patients undergoing PCI without prior CABG. In these patients, native vessel PCI was associated with better outcomes compared to the treatment of vein grafts.

P2665An observational study assessing the impact of a cardiac arrest centre on patient outcome

Background

Out-of-hospital cardiac arrest (OHCA) is a major cause of death in Europe and the United States. There has been recent literature to suggest that the centralisation of OHCA services may benefit patient outcomes. In 2015, two major tertiary cardiac centres in the UK agglomerated to form a large dedicated tertiary cardiac centre. The previous centre had strict criteria on which OHCA patients could be admitted, with the vast majority of cases being STEMI-related. After the agglomeration, admission criteria were relaxed to include all OHCA cases within geographic range with a suspected cardiac cause.

Purpose

This study aimed to compare the short-term mortality of patients admitted with an OHCA to a tertiary cardiac centre before-and-after a major agglomeration of services had taken place and admission criteria had been relaxed.

Methods

We retrospectively analysed the data of patients admitted before and after agglomeration (2015) with OHCA who were resuscitated via conventional cardiopulmonary resuscitation. Baseline demographic characteristics were recorded, along with factors relating to the cardiac arrest. Primary endpoint was in-hospital mortality.

Results

A total of 650 patients (189 before and 461 after the agglomeration) with an OHCA between 2013 and 2018 were analysed. Patients admitted pre merger were older (67.7 vs 62.4 years, p=0.022), otherwise there were similar baseline demographic characteristics between patients admitted before and after the agglomeration (pre vs post) in terms of gender (74.4% vs 75.9% male, p=0.827), ethnicity (66.7% vs 58.9% Caucasian, p=0.588) and existing coronary artery disease (22.8% vs 22.7%, p=0.432). There were also similar peri-arrest characteristics, with a comparable number of patients having a non-shockable rhythm (15.4% vs 25.4%, p=0.164) and similar total downtimes between the groups (33 vs 32.3 mins, p=0.883). Interestingly there was a decrease in those with cardiogenic shock on arrival (92.3% vs 57.0%, p=0.0001) and fewer patients with an ejection fraction <30% (63.2 vs 38.7%, p=0.0003) post-agglomeration.

There was a greater proportion of non-ACS-related OHCA admission after the agglomeration (16.9% vs 24.1%, p=0.047) and a corresponding decrease in those admitted with a STEMI (81.5% vs 62.3%, p=0.032) and those treated with PCI (77.8% vs 54.0%, p=0.034). Despite this, in-hospital mortality was lower after the agglomeration (69.7% vs 47.1%, p=0.019), which persisted after adjustment for the previously described demographic and arrest-related characteristics using stepwise logistic regression (p=0.036) between the two groups.

Conclusion

Despite an increase in non-ACS-related-OHCA cases, the formation of a centralised invasive heart centre was associated with improved survival in OHCA patients. This suggests there may be a benefit for an out-of-hospital cardiac arrest-centre model of care, supporting a centralised strategy for immediate post-resuscitation care in OHCA patients.

Acknowledgement/Funding

None

Cholinesterase Inhibitory Arisugacins L-Q from a Penicillium sp. Isolate Obtained through a Citizen Science Initiative and Their Activities in a Phenotype-Based Zebrafish Assay

Phenotype-based screening of a fungal extract library yielded an active sample from a Penicillium sp. isolate that impaired zebrafish motility. Bioassay-guided purification led to the identification of 14 meroterpenoids including six new metabolites, arisugacins L-Q (4, 5, 8, and 12-14), seven known arisugacins (1-3, 6, 7, 9, and 10), and one known terreulactone (11). Their structures were determined using a combination of NMR and HRESIMS data, evidence secured from theoretical and experimental ECD spectra, and the modified Mosher's method. The purified compounds were tested in zebrafish embryos, as well as in vitro for cholinesterase inhibition activities. Compound 12 produced defects in myotome structure (metameric muscle, which is critical for locomotion) in vivo and showed the most potent and selective acetylcholinesterase inhibitory activity with an IC₅₀ of 191 nM in vitro. The phenotype assay was also used to reveal bioactivities for several previously reported arisugacins, which had failed to show activity in prior cell-based and in vitro testing. This study demonstrates that utilization of the zebrafish phenotype assay is an effective approach for the identification of bioactive extracts, is compatible with the bioassay-guided compound purification strategies, and offers a valuable tool for probing complex natural product sources to detect bioactive small molecules with potential therapeutic or other commercial applications.

The contribution of low-frequency fatigue to the loss of quadriceps contractile function following repeated drop jumps

NEW FINDINGS

What is the central question of this study? Why do some subjects recover slowly following a bout of eccentric exercise and why is recovery faster following a repeated bout? What is the main finding and its importance? The results are consistent with two major causes of the reduction of quadriceps torque, the onset of low-frequency fatigue which recovered relatively fast and a second, delayed form of damage. Differences in the delayed damage process largely accounted for the differences in the rate of torque recovery between subjects after a first bout and it was suppression of the delayed damage which accounted for the faster recovery following a repeated bout of eccentric exercise.

ABSTRACT

The purpose of this study was to determine the extent to which low-frequency fatigue (LFF) accounts for the loss of quadriceps strength and time course of recovery following a series of drop jumps (DJs). Seventeen female subjects (20.8 ± 1.4 years) undertook 100 DJs, which were repeated 4 weeks later. Maximum isometric torque (MIT) and the ratio of torque generated by 20 and 100 Hz electrical stimulation (20/100), as a measure of LFF, were measured over 7 days following each series of DJs. After the first series the 20/100 ratio fell to a greater extent than MIT (to 35 ± 8.7% and 69 ± 11%, respectively) but recovered over 2-3 days, while MIT showed little recovery over this time. Changes of the 20/100 ratio were similar between subjects with fast or slow MIT recovery. Following the second series of DJs, changes in the 20/100 ratio were similar to those of the first bout and there were no differences between fast and slow recovering subjects. MIT, however, recovered more rapidly than after the first bout; the faster recovery was confined to the subjects who recovered slowly following the first bout. The results are consistent with two major causes of the reduction of quadriceps torque, the onset of low-frequency fatigue which recovered relatively fast and a second, delayed, form of damage. The latter largely accounted for the differences in MIT recovery between subjects after the first bout, while suppression of the delayed damage accounted for the faster recovery following the repeated bout.

Combined Resistance and Stretching Exercise Training Benefits Stair Descent Biomechanics in Older Adults

Introduction

Stair descent is a physically demanding activity of daily life and common risk for falls. Age-related deteriorations in ankle joint capacities make stair descent particularly challenging for older adults in built environments, where larger rise steps are encountered. Exercise training may allow older adults to safely cope with the high biomechanical demands of stair descent. However, little is known about the demands of increased rise stairs for older adults, nor the impact of exercise.

Aim

We investigated whether the effects of lower-limb resistance training would alter joint kinetics and movement strategies for older adults when descending standard rise, and increased rise stairs.

Methods

Fifteen older adults descended a four-step stair adjusted to standard rise (170 mm), and increased rise (255 mm) on separate visits. Between these two visits, randomly allocated participants underwent 16 weeks of either: resistance exercise training (n = 8) or habitual activity (n = 7). Kinetic data were measured from step-mounted force plates, and kinematic data from motion-capture cameras. Training involved twice-weekly sessions of lower-limb resistance exercises (three sets of ∼8 repetitions at ∼80% three-repetition maximum), and static plantarflexor stretching (three, 45 s holds per leg).

Results

Standard stairs – Peak ankle joint moments increased (p < 0.002) and knee joint moments decreased (p < 0.01) during descent after exercise training. Peak centre of pressure-centre of mass (CoP-CoM) separations increased in posterior (p = 0.005) and medio-lateral directions (p = 0.04) after exercise training. Exercise training did not affect CoM descent velocity or acceleration. Increased rise stairs – Required greater ankle, knee, and hip moments (p < 0.001), peak downward CoM velocity and acceleration (p = 0.0001), and anterior-posterior CoP-CoM separation (p = 0.0001), but lower medial-lateral CoP-CoM separation (p < 0.05), when compared to standard stair descent. Exercise training did not affect joint kinetics or movement strategies.

Discussion

Exercise training increased the maximum joint ROM, strength and force production of the ankle, and enabled a greater ankle joint moment to be produced in single-leg support (lowering phase) during standard stair descent. Descending increased rise stairs raised the task demand; exercise training could not overcome this. Future research should prioritize the ankle joint in stair descent, particularly targeting plantarflexor torque development across stairs of varying riser heights.

Frailty phenotype and frailty index are associated with distinct neuromuscular electrophysiological characteristics in men

NEW FINDINGS

What is the central question of this study? Human frailty is characterized by accumulated health complaints, including medical conditions, low physical and psychological function and social components. It is currently unknown whether the condition is associated with neuromuscular changes detectable by electrophysiology obtained from voluntary and involuntary muscle contractions. What is the main finding and its importance? A higher likelihood of frailty was significantly associated with a smaller size of vastus lateralis motor unit potentials during voluntary contractions and smaller compound muscle action potentials generated by electrical stimulation. Importantly, these associations were independent of age and body mass index.

ABSTRACT

The purpose of this study was to determine whether neuromuscular electrophysiological characteristics that are known to underlie sarcopenia are also associated with the more complex frailty syndrome. Eighty-six men [mean (SD) age, 74 (8) years] were classed as non-frail (robust), prefrail or frail using criteria from the frailty phenotype (FP) and the frailty index (FI). The femoral nerve was stimulated maximally and the resulting compound muscle action potential amplitude (CMAP) measured over the vastus lateralis. Motor unit potential (MUP) size was assessed during voluntary contractions using intramuscular electromyography (iEMG). Logistic and negative binomial regression models determined relationships between FP and FI with CMAP and MUP sizes before and after adjustments for age and body mass index. Larger CMAP size was associated with a lower likelihood of frailty in fully adjusted models: a 1SD higher level in vastus lateralis CMAP size was associated with a 0.4 (95% confidence interval: 0.2, 0.6; P < 0.01) unit lower FI (40% of the FI range) and more than halving of the odds [odds ratio: 0.43 (95% confidence interval: 0.21, 0.90)] of having a frail/prefrail phenotype. Greater MUP size was also related to lower FI values using unadjusted and fully adjusted models. However, MUP size was not significantly related to FP in any model. Smaller MUPs and a smaller CMAP were significantly associated with a higher likelihood of frailty, independent of age and body mass index. These results relate neuromuscular electrophysiological characteristics to the complex frailty syndrome and identify motor unit remodelling as a possible contributing factor.

Toxic effects of a methanolic coal dust extract on fish early life stage

Coal dust is a contaminant that impacts the terrestrial and aquatic environment with a complex mixture of chemicals, including PAHs and metals. This study aims to evaluate the toxic effect of a methanolic coal dust extract on a fish early life stage by analyzing phenotypic alterations, transcriptome changes, and mortality in zebrafish (ZF) embryos. ZF embryos were exposed to methanolic coal dust extract at 1-5000 mg·L-1 and monitored using bright field microscopy 24 and 48 hpf to determine malformations and mortality. In situ hybridization, RNA sequencing, and qRT-PCR were employed to identify transcriptome changes in malformed embryos. Three malformed phenotypes were generated in a dose-dependent manner. In situ hybridization analysis revealed brain, somite, dorsal cord, and heart tube development biomarker alterations. Gene expression profile analysis identified changes in genes related to structural constituent of muscle, calcium ion binding, actin binding, melanin metabolic process, muscle contraction, sarcomere organization, cardiac myofibril assembly, oxidation-reduction process, pore complex, supramolecular fiber, striated muscle thin filament, Z disc, and intermediate filament. This study shows, for the first time, the malformations generated by a mixture of pollutants from a methanolic coal dust extract on a fish early life stage, constituting a potential risk for normal embryonic development of other aquatic vertebrate organisms. Furthermore, we establish that phenotypes and changes in gene expression induced by the extract constitute a target for future studies about mechanical toxicity and their utility as sensitive tools in environmental risk assessments for biota and humans exposed to coal mining activities.

The effects of slow loaded breathing training on exercise blood pressure in isolated systolic hypertension

OBJECTIVES

Slow loaded breathing training has been shown to reduce resting blood pressure (BP) in isolated systolic hypertension (ISH), but it is not known whether this also reduces their exaggerated BP responses to exercise.

METHODS

The study was a randomized controlled trial with block allocation stratified by sex. Twenty ISH patients (68 ± 5 yrs, 11 males) were randomized with one group undertaking 8-weeks training with slow loaded breathing (SLB: 25% maximum inspiratory pressure, 6 breaths per minute, 60 breaths every day) or deep breathing control (CON), with 8 weeks follow-up. Outcome measures were home BP and heart rate (HR) with laboratory measures of BP and HR responses to static handgrip and dynamic arm cranking exercise. Data were compared with a two-week run-in baseline.

RESULTS

Home systolic BP fell by 22 mmHg (20-23; mean, 95% CI), diastolic BP by 9 mmHg (7-11), and HR by 12 bpm (9-15; all p < .001) as a result of SLB training. Systolic BP at the end of 2-min isometric handgrip was 189 ± 10 mmHg (mean, SD) before training and 157 ± 6 mmHg following SLB training. After 4-min arm exercise, systolic BP, measured at the ankle, was reduced from 243 ± 8 mmHg during the run-in period to 170 ± 15 mmHg after SLB training with no change for CON. The reduction in exercise BP, in both types of exercise, was partly due to a reduction in resting BP and to a smaller increase above resting. Systolic and pulse pressures remained below run-in values 8 weeks after the end of SLB training, and BP response to handgrip exercise remained below run-in values at 4 weeks after SLB training.

CONCLUSIONS

SLB not only reduces resting BP in ISH but also the responses to both static and dynamic exercise, potentially reducing the negative aspect of exercise for cardiovascular health.

Structural and functional insights into the modulation of the activity of a flax cytokinin oxidase by flax rust effector AvrL567-A

During infection, plant pathogens secrete effector proteins to facilitate colonization. In comparison with our knowledge of bacterial effectors, the current understanding of how fungal effectors function is limited. In this study, we show that the effector AvrL567-A from the flax rust fungus Melampsora lini interacts with a flax cytosolic cytokinin oxidase, LuCKX1.1, using both yeast two-hybrid and in planta bimolecular fluorescence assays. Purified LuCKX1.1 protein shows catalytic activity against both N6-(Δ2-isopentenyl)-adenine (2iP) and trans-zeatin (tZ) substrates. Incubation of LuCKX1.1 with AvrL567-A results in increased catalytic activity against both substrates. The crystal structure of LuCKX1.1 and docking studies with AvrL567-A indicate that the AvrL567 binding site involves a flexible surface-exposed region that surrounds the cytokinin substrate access site, which may explain its effect in modulating LuCKX1.1 activity. Expression of AvrL567-A in transgenic flax plants gave rise to an epinastic leaf phenotype consistent with hormonal effects, although no difference in overall cytokinin levels was observed. We propose that, during infection, plant pathogens may differentially modify the levels of extracellular and intracellular cytokinins.

Slow torque recovery after eccentric exercise and the repeated bout effect; the role of primary and secondary muscle damage

OBJECTIVES

To determine the role of primary and secondary damage in the variation between people of maximum voluntary contraction (MVC) torque recovery following eccentric exercise and the faster recovery following a repeated bout of exercise.

METHODS

Twenty-one healthy, active but untrained young female subjects undertook eccentric exercise of the elbow flexors and 11 repeated the exercise 28 days later. Changes of MVC torque and creatine kinase (CK) were followed for 7 days after each bout of exercise.

RESULTS

Following the first bout, 45% of subjects showed a continuing decline in MVC torque, suggesting secondary damage, which was correlated with a large delayed CK release (R²=0.54, p<0.001). After the second bout of exercise, the initial MVC torque loss was similar to that after the first bout while torque recovery was faster, but only for the previously slow recovering subjects. Comparing the time course of MVC torque recovery of first and second bouts suggests secondary damage develops over 4 days.

CONCLUSIONS

The data are consistent with primary damage being similar between subjects and unaffected by the repeated bout while it is secondary damage which accounts for differences in MVC torque recovery and is suppressed following a repeated bout of exercise.

Evidence for horizontal gene transfer and separation of effector recognition from effector function revealed by analysis of effector genes shared between cape gooseberry- and tomato-infecting formae speciales of Fusarium oxysporum

RNA sequencing (RNAseq) reads from cape gooseberry plants (Physalis peruviana) infected with Fusarium oxysporumf. sp. physali (Foph) were mapped against the lineage-specific transcriptome of Fusarium oxysporumf. sp. lycopersici (Fol) to look for putative effector genes. Homologues of Fol SIX1(designated SIX1a and SIX1b), SIX7, SIX10, SIX12, SIX15 and Ave1were identified. The near identity of the Foph and Fol SIX7, SIX10 and SIX12genes and their intergenic regions suggest that this gene cluster may have undergone recent lateral transfer. Foph SIX1a and SIX1bwere tested for their ability to complement a SIX1 knockout mutant of Fol. This mutant shows reduced pathogenicity on susceptible tomato plants, but is able to infect otherwise resistant tomato plants carrying the I-3 gene for Fusarium wilt resistance (SIX1 corresponds to Avr3). Neither SIX1a nor SIX1b could restore full pathogenicity on susceptible tomato plants, suggesting that any role they may play in pathogenicity is likely to be specific to cape gooseberry. SIX1b, but not SIX1a, was able to restore avirulence on tomato plants carrying I-3.These findings separate the recognition of SIX1 from its role as an effector and suggest direct recognition by I-3. A hypervariable region of SIX1undergoing diversifying selection within the F. oxysporum species complex is likely to play an important role in SIX1 recognition. These findings also indicate that I-3could potentially be deployed as a transgene in cape gooseberry to protect this emerging crop from Foph.Alternatively, cape gooseberry germplasm could be explored for I-3homologues capable of providing resistance to Foph.

The Contributions of Fiber Atrophy, Fiber Loss, In Situ Specific Force, and Voluntary Activation to Weakness in Sarcopenia

The contributions of fiber atrophy, fiber loss, in situ specific force, and voluntary activation to weakness in sarcopenia remain unclear. To investigate, 40 older (20 women; age 72 ± 4 years) and 31 younger adults (15 women, age 22 ± 3 years) completed measurements. The knee extensor maximal voluntary torque (MVC) was measured as well as voluntary activation, patella tendon moment arm length, muscle volume, and fascicle architecture to estimate in situ specific force. Fiber cross-sectional area (FCSA), fiber numbers, and connective tissue contents were also estimated from vastus lateralis biopsies. The MVC, quadriceps volume, and specific force were 39%, 28%, and 17% lower, respectively, in old compared with young, but voluntary activation was not different. The difference in muscle size was due in almost equal proportions to lower type II FCSA and fewer fibers. Five years later (n = 23) the MVC, muscle volume and voluntary activation in old decreased an additional 12%, 6%, and 4%, respectively, but there was no further change in specific force. In situ specific force declines relatively early in older age and reduced voluntary activation occurs later, but the overall weakness in sarcopenia is mainly related to loss of both type I and II fibers and type II fiber atrophy.