Characterization of Spatiooral Cardiac Action Potential Variability at Baseline and under ß-Adrenergic Stimulation by Combined Unscented Kalman Filter and Double Greedy Dimension Reduction

Objective: Elevated spatiooral variability of human ventricular repolarization has been related to increased risk for ventricular arrhythmias and sudden cardiac death, particularly under ß-adrenergic stimulation (ß-AS). This work presents a methodology for theoretical characterization of temporal and spatial repolarization variability at baseline conditions and in response to ß-AS. For any measured voltage trace, the proposed methodology estimates the parameters and state variables of an underlying human ventricular action potential (AP) model by combining Double Greedy Dimension Reduction (DGDR) with automatic selection of biomarkers and the Unscented Kalman Filter (UKF). Such theoretical characterization can facilitate subsequent characterization of underlying variability mechanisms. Material and Methods: Given an AP trace, initial estimates for the ionic conductances in a stochastic version of the baseline human ventricular O'Hara et al. model were obtained by DGDR. Those estimates served to initialize and update model parameter estimates by the UKF method based on formulation of an associated nonlinear state-space representation and joint estimation of model parameters and state variables. Similarly, ß-AS-induced phosphorylation levels of cellular substrates were estimated by the DGDR-UKF methodology. Performance was tested by building an experimentally-calibrated population of virtual cells, from which synthetic AP traces were generated for baseline and ß-AS conditions. Results: The combined DGDR-UKF methodology led to 25% reduction in the error associated with estimation of ionic current conductances at baseline conditions and phosphorylation levels under ß-AS with respect to individual DGDR and UKF methods. This improvement was not at the expense of higher computational load, which was diminished by 90% with respect to the individual UKF method. Both temporal and spatial AP variability of repolarization were accurately characterized by the DGDR-UKF methodology. Conclusions: A combined DGDR-UKF methodology is proposed for parameter and state variable estimation of human ventricular cell models from available AP traces at baseline and under ß-AS. This methodology improves the estimation performance and reduces the convergence time with respect to individual DGDR and UKF methods and renders a suitable approach for computational characterization of spatiooral repolarization variability to be used for ascertainment of variability mechanisms and its relation to arrhythmogenesis

Complex Interaction Between Low-Frequency APD Oscillations and Beat-to-Beat APD Variability in Humans Is Governed by the Sympathetic Nervous System

Background: Recent clinical, experimental and modeling studies link oscillations of ventricular repolarization in the low frequency (LF) (approx. 0.1 Hz) to arrhythmogenesis. Sympathetic provocation has been shown to enhance both LF oscillations of action potential duration (APD) and beat-to-beat variability (BVR) in humans. We hypothesized that beta-adrenergic blockade would reduce LF oscillations of APD and BVR of APD in humans and that the two processes might be linked. Methods and Results: Twelve patients with normal ventricles were studied during routine electrophysiological procedures. Activation-recovery intervals (ARI) as a conventional surrogate for APD were recorded from 10 left and 10 right ventricular endocardial sites before and after acute beta-adrenergic adrenergic blockade. Cycle length was maintained constant with right ventricular pacing. Oscillatory behavior of ARI was quantified by spectral analysis and BVR as the short-term variability. Beta-adrenergic blockade reduced LF ARI oscillations (8.6 ± 4.5 ms2 vs. 5.5 ± 3.5 ms2, p = 0.027). A significant correlation was present between the initial control values and reduction seen following beta-adrenergic blockade in LF ARI (rs = 0.62, p = 0.037) such that when initial values are high the effect is greater. A similar relationship was also seen in the beat-to beat variability of ARI (rs = 0.74, p = 0.008). There was a significant correlation between the beta-adrenergic blockade induced reduction in LF power of ARI and the witnessed reduction of beat-to-beat variability of ARI (rs = 0.74, p = 0.01). These clinical results accord with recent computational modeling studies which provide mechanistic insight into the interactions of LF oscillations and beat-to-beat variability of APD at the cellular level. Conclusion: Beta-adrenergic blockade reduces LF oscillatory behavior of APD (ARI) in humans in vivo. Our results support the importance of LF oscillations in modulating the response of BVR to beta-adrenergic blockers, suggesting that LF oscillations may play role in modulating beta-adrenergic mechanisms underlying BVR

Transcriptomic differences in MSA clinical variants

Background: Multiple system atrophy (MSA) is a rare oligodendroglial synucleinopathy of unknown etiopathogenesis including two major clinical variants with predominant parkinsonism (MSA-P) or cerebellar dysfunction (MSA-C). Objective: To identify novel disease mechanisms we performed a blood transcriptomic study investigating differential gene expression changes and biological process alterations in MSA and its clinical subtypes. Methods: We compared the transcriptome from rigorously gender and age-balanced groups of 10 probable MSA-P, 10 probable MSA-C cases, 10 controls from the Catalan MSA Registry (CMSAR), and 10 Parkinson Disease (PD) patients. Results: Gene set enrichment analyses showed prominent positive enrichment in processes related to immunity and inflammation in all groups, and a negative enrichment in cell differentiation and development of the nervous system in both MSA-P and PD, in contrast to protein translation and processing in MSA-C. Gene set enrichment analysis using expression patterns in different brain regions as a reference also showed distinct results between the different synucleinopathies. Conclusions: In line with the two major phenotypes described in the clinic, our data suggest that gene expression and biological processes might be differentially affected in MSA-P and MSA-C. Future studies using larger sample sizes are warranted to confirm these results

Bronchial Thermoplasty Global Registry (BTGR) : 2-year results

Funding This study was sponsored by Boston Scientific Corporation, Marlborough, MA, USA.Objectives Bronchial thermoplasty (BT) is a device-based treatment for subjects ≥18 years with severe asthma not well controlled with inhaled corticosteroids and long-acting beta-agonists. The Bronchial Thermoplasty Global Registry (BTGR) collected real-world data on subjects undergoing this procedure. Design The BTGR is an all-comer, prospective, open-label, multicentre study enrolling adult subjects indicated for and treated with BT. Setting Eighteen centres in Spain, Italy, Germany, the UK, the Netherlands, the Czech Republic, South Africa and Australia Participants One hundred fifty-seven subjects aged 18 years and older who were scheduled to undergo BT treatment for asthma. Subjects diagnosed with other medical conditions which, in the investigator's opinion, made them inappropriate for BT treatment were excluded. Primary and secondary outcome measures Baseline characteristics collected included demographics, Asthma Quality of Life Questionnaire (AQLQ), Asthma Control Test (ACT), medication usage, forced expiratory volume in one second and forced vital capacity, medical history, comorbidities and 12-month baseline recall data (severe exacerbations (SE) and healthcare utilisation). SE incidence and healthcare utilisation were summarised at 1 and 2 years post-BT. Results Subjects' baseline characteristics were representative of persons with severe asthma. A comparison of the proportion of subjects experiencing events during the 12 months prior to BT to the 2-year follow-up showed a reduction in SE (90.3% vs 56.1%, p<0.0001), emergency room visits (53.8% vs 25.5%, p<0.0001) and hospitalisations (42.9% vs 23.5 %, p=0.0019). Reductions in asthma maintenance medication dosage were also observed. AQLQ and ACT scores improved from 3.26 and 11.18 at baseline to 4.39 and 15.54 at 2 years, respectively (p<0.0001 for both AQLQ and ACT). Conclusions The BTGR demonstrates sustained improvement in clinical outcomes and reduction in asthma medication usage 2 years after BT in a real-world population. This is consistent with results from other BT randomised controlled trials and registries and further supports improvement in asthma control after BT. Trial registration number NCT02104856

A correlative biomarker study and integrative prognostic model in chemotherapy-naïve metastatic castration-resistant prostate cancer treated with enzalutamide

There is a considerable need to incorporate biomarkers of resistance to new antiandrogen agents in the management of castration-resistant prostate cancer (CRPC). We conducted a phase II trial of enzalutamide in first-line chemo-naïve asymptomatic or minimally symptomatic mCRPC and analyzed the prognostic value of TMPRSS2-ERG and other biomarkers, including circulating tumor cells (CTCs), androgen receptor splice variant (AR-V7) in CTCs and plasma Androgen Receptor copy number gain (AR-gain). These biomarkers were correlated with treatment response and survival outcomes and developed a clinical-molecular prognostic model using penalized cox-proportional hazard model. This model was validated in an independent cohort. Ninety-eight patients were included. TMPRSS2-ERG fusion gene was detected in 32 patients with no differences observed in efficacy outcomes. CTC detection was associated with worse outcome and AR-V7 in CTCs was associated with increased rate of progression as best response. Plasma AR gain was strongly associated with an adverse outcome, with worse median prostate specific antigen (PSA)-PFS (4.2 vs. 14.7 m; p < 0.0001), rad-PFS (4.5 vs. 27.6 m; p < 0.0001), and OS (12.7 vs. 38.1 m; p < 0.0001). The clinical prognostic model developed in PREVAIL was validated (C-Index 0.70) and the addition of plasma AR (C-Index 0.79; p < 0.001) increased its prognostic ability. We generated a parsimonious model including alkaline phosphatase (ALP); PSA and AR gain (C-index 0.78) that was validated in an independent cohort. TMPRSS2-ERG detection did not correlate with differential activity of enzalutamide in first-line mCRPC. However, we observed that CTCs and plasma AR gain were the most relevant biomarkers

Scientific Opinion on the safety and efficacy of Bacillus subtilis KCCM 10673P and Aspergillus oryzae KCTC 10258BP as feed additives for all animal species

PepSoyGen-C is described as pure cultures of Aspergillus oryzae and Bacillus subtilis added simultaneously to feed materials to reduce antinutritional factors. The applicant is seeking its authorisation as a technological additive, under a newly proposed, currently non-existent functional group, "substances for the reduction of antinutritional factors". The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) considers that the two microbial cultures should be regarded as two independent feed additives that are the subject of the evaluation. The additives are poorly characterised. The inclusion level is likely to be 2 % by weight of the total substrate. The ratio of the two cultures is described as 50/50 on a weight basis. A dose expressed in colony-forming units per kilogram of feed is not proposed. No evidence of toxigenic potential or resistance to antibiotics of human and veterinary importance was found, according to the current guidance documents. Therefore, the B. subtilis additive is presumed safe for target animals, consumers of products fed the additive and the environment. The B. subtilis additive should be considered as having the potential to be a skin and eye irritant and a skin sensitiser and be treated accordingly. In the absence of data on production of toxic secondary metabolites in A. oryzae, the FEEDAP Panel cannot draw conclusions on its safety for the target species and consumers of products fed the additive. The A. oryzae additive should be considered as having the potential to be a skin and eye irritant and a skin and respiratory sensitiser and be treated accordingly. The use of the additive as a technological feed additive is not expected to pose a risk to the environment. The FEEDAP Panel cannot draw conclusions on the efficacy of the additives in reducing antinutritional factors in soybean and other feed materials

Scientific Opinion on the safety and efficacy of L-threonine produced by Escherichia coli strains NRRL B-30843, DSM 26131, KCCM11133P or DSM 25085 for all animal species based on a dossier submitted by AMAC EEIG

This opinion concerns L-threonine as a feed additive produced by four different strains derived from Escherichia coli K-12. Three strains are genetically modified (GM): NRRL B-30843, KCCM11133P and DSM 26131. L-Threonine produced by E. coli DSM 26131 could not be assessed because of the insufficient molecular characterisation of the genetic modification, and the lack of data on both the absence of the production strain and its recombinant DNA from the final product. No safety concerns were found in the products related to the genetic modification of the other GM strains or to antibiotic resistance of the producer strains. L-Threonine products made by fermentation using E. coli strains NRRL B-30843, KCCM11133P and DSM 25085 are free of the production strain and have a high purity (>= 98.8 %). L-Threonine, technically pure, produced by E. coli strains NRRL B-30843, KCCM11133P and DSM 25085 is safe for the target animals when used in appropriate amounts to supplement threonine-deficient feeds, for the consumer of animal products and for the environment. The FEEDAP Panel considers that L-threonine produced by E. coli strains NRRL B-30843, KCCM11133P or DSM 25085 is not an irritant to eyes and skin, and is not a skin sensitiser. There is no risk from inhalation of L-threonine, but concerns may arise from the content of endotoxins in the products. These L-threonine products are considered an efficacious source of the amino acid L-threonine for all animal species. For L-threonine to be as efficacious in ruminants as in non-ruminant species, it requires protection against degradation in the rumen. The Panel on Additives and Products or Substances used in Animal Feed ( FEEDAP) has concerns regarding the safety of the simultaneous oral administration of L-threonine via water for drinking and feed

Scientific Opinion on the safety and efficacy of sorbic acid and potassium sorbate when used as technological additives for all animal species based on two dossiers from Nutrinova Nutrition Specialties &amp; Food Ingredients GmbH

Sorbic acid and potassium sorbate are already authorised for use in food and feed as preservatives. Sorbic acid and potassium sorbate are safe when used at the maximum proposed dose in feed for pigs, poultry, dogs and cats (2 500 (sorbic acid) and 3 400 (potassium sorbate) mg/kg complete feed) and young ruminants (6 700 (sorbic acid) and 9 000 (potassium sorbate) mg/kg complete feed). This conclusion is extended to all other animal species at maximum concentrations of 2 500 (sorbic acid) and 3 400 (potassium sorbate) mg/kg complete feed. Both additives are considered safe for target animals when used in water for drinking, provided that the same maximum exposure is respected. No residues of sorbic acid or potassium ions are expected in edible products of food-producing animals when fed sorbic acid or potassium sorbate at the maximum proposed concentrations. Therefore, their use in feed up to the maximum proposed level is considered safe for the consumer. Sorbic acid and potassium sorbate are skin, eye and respiratory tract irritants. The use of sorbic acid and its potassium salt in animal nutrition would not pose a risk to the environment. As sorbic acid and potassium sorbate are food additives authorised within the EU for use as preservatives, it is reasonable to expect that the effect in food will be observed in feed when used at comparable concentrations and under similar conditions. The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) has reservations about the effectiveness of sorbic acid and its potassium salt as preservatives in complete feedingstuffs with a moisture content of <= 12 %