Terminal T-wave inversion predicts reperfusion tachyarrhythmias in STEMI.

INTRODUCTION: A reliable electrocardiographic predictor of ventricular fibrillation (VF) in patients with ST elevation myocardial infarction (STEMI) is lacking so far. Previous experimental/simulation study suggested a terminal T-wave inversion (TTWI) in ischemia-related ECG leads corresponding to anterior infarct localization as an independent predictor of reperfusion VF (rVF). This T-wave characteristic has never been tested as a rVF predictor in clinical settings. The aim of this study was to test if terminal T-wave inversion (TTWI) at admission ECG (before reperfusion) can serve as a predictor of ventricular fibrillation during reperfusion (rVF) in patients with anterior STEMI undergoing primary PCI. METHODS AND RESULTS: Study population included consecutive patients with anterior infarct localization admitted for primary PCI (n = 181, age 65 [57; 76] years, 66% male). Of those, 14 patients had rVF (rVF group, age 59 [47; 76] years, 64% male) and patients without rVF comprised the No-rVF group (n = 167, age 65 [57; 76] years, 66% male). Association of TTWI with rVF was analyzed using logistic regression analysis adjusted for relevant clinical and electrocardiographic covariates. The prevalence of TTWI in rVF group was 62% comparing to 23% in the No-rVF group, p = 0.005. TTWI was associated with increased risk of rVF (OR 5.51; 95% CI 1.70-17.89; p = 0.004) and remained a significant predictor after adjustment for age, gender, history of MI prior to index admission, VF before reperfusion, Tpeak-Tend, maximal ST elevation, and QRS duration (OR 23.49; 95% CI 3.14-175.91; p = 0.002). CONCLUSIONS: The terminal T-wave inversion in anterior leads before PCI independently predicted rVF in patients with anterior MI thus confirming the previous experimental/simulation findings.

Depletion of Retinal Dopaminergic Activity in a Mouse Model of Rod Dysfunction Exacerbates Experimental Autoimmune Uveoretinitis: A Role for the Gateway Reflex.

The gateway reflex is a mechanism by which neural inputs regulate chemokine expression at endothelial cell barriers, thereby establishing gateways for the invasion of autoreactive T cells into barrier-protected tissues. In this study, we hypothesized that rod photoreceptor dysfunction causes remodeling of retinal neural activity, which influences the blood-retinal barrier and the development of retinal inflammation. We evaluated this hypothesis using Gnat1rd17 mice, a model of night blindness with late-onset rod-cone dystrophy, and experimental autoimmune uveoretinitis (EAU). Retinal remodeling and its effect on EAU development were investigated by transcriptome profiling, target identification, and functional validation. We showed that Gnat1rd17 mice primarily underwent alterations in their retinal dopaminergic system, triggering the development of an exacerbated EAU, which was counteracted by dopamine replacement with L-DOPA administered either systemically or locally. Remarkably, dopamine acted on retinal endothelial cells to inhibit NF-κB and STAT3 activity and the expression of downstream target genes such as chemokines involved in T cell recruitment. These results suggest that rod-mediated dopamine release functions in a gateway reflex manner in the homeostatic control of immune cell entry into the retina, and the loss of retinal dopaminergic activity in conditions associated with rod dysfunction increases the susceptibility to autoimmune uveitis.

Multi-lead vs single-lead Tpeak -T end interval measurements for prediction of reperfusion ventricular tachyarrhythmias.

INTRODUCTION: Electrocardiographic Tpeak -Tend interval (Tp-Te) is a promising marker for the prediction of ventricular tachycardia and/or ventricular fibrillation (VT/VF). The study was aimed to compare single-lead vs multilead Tp-Te variables as VT/VF predictors in experimental ischemia/reperfusion model. METHODS AND RESULTS: Computer simulations were done using the ECGSIM model with an ischemic region set in anterior left ventricular apex. In 18 anesthetized cats, myocardial ischemia was induced by 30-minute ligation of left anterior descending coronary artery followed by reperfusion. Body surface ECGs in limb leads and modified precordial leads were recorded. Tp-Te was detected automatically in individual leads with a custom-designed parametric algorithm. Tp-Te dispersion and total Tp-Te were calculated as a difference between the maximal and minimal value of individual Tp-Te(s) and an interval between the earliest Tpeak and the latest Tend throughout all leads, respectively. Simulations showed that the increase of local, but not total, dispersion of repolarization characteristic for ischemic damage led to nonuniform shortening of T-peak times across 12 standard leads, which in turn resulted in the increase of single-lead Tp-Te(s), total Tp-Te and Tp-Te dispersion. Animals experienced VT/VF showed increased Tp-Te dispersion and total Tp-Te during reperfusion. In univariate logistic regression analysis, only the Tp-Te dispersion at the beginning of reperfusion was associated with the VT/VF incidence. According to ROC curve analysis, the optimal cut-off value of the Tp-Te dispersion was 17 ms (sensitivity 0.71, specificity 0.80). CONCLUSIONS: The reperfusion VT/VFs were independently predicted by increased Tp-Te dispersion, which suggests the importance of multi-lead evaluation of Tp-Te intervals.

Visual stimulation and brain-derived neurotrophic factor (BDNF) have protective effects in experimental autoimmune uveoretinitis.

AIMS: To investigate the therapeutic potential of visual stimulation (VS) and BDNF in murine experimental autoimmune uveoretinitis (EAU). MAIN METHODS: Mice were immunized by subcutaneous injection of interphotoreceptor retinoid-binding protein in Freund's complete adjuvant and intravenous injection of pertussis toxin, and were then exposed to high-contrast VS 12 h/day (days 1-14 post-immunization). EAU severity was assessed by examining clinical score, visual acuity, inflammatory markers, and immune cells in the retina. The transcriptome of activated retinal cells was determined by RNA-seq using RNA immunoprecipitated in complex with phosphorylated ribosomal protein S6. The retinal levels of protein products of relevant upregulated genes were quantified. The effect of BDNF on EAU was tested in unstimulated mice by its daily topical ocular administration (days 8-14 post-immunization). KEY FINDINGS: VS attenuated EAU development and decreased the expression of pro-inflammatory cytokines/chemokines and numbers of immune cells in the retina (n = 10-20 eyes/group for each analysis). In activated retinal cells of control mice (n = 30 eyes/group), VS upregulated genes encoding immunomodulatory neuropeptides, of which BDNF and vasoactive intestinal peptide (VIP) also showed increased mRNA and protein levels in the retina of VS-treated EAU mice (n = 6-10 eyes/group for each analysis). In unstimulated EAU mice, BDNF treatment mimicked the protective effects of VS by modulating the inflammatory and stem cell properties of Müller cells (n = 5 eyes/group for each analysis). SIGNIFICANCE: VS effectively suppresses EAU, at least through enhancing retinal levels of anti-inflammatory and neuroprotective factors, VIP and BDNF. Our findings also suggest BDNF as a promising therapeutic agent for uveitis treatment.

Evaluation of functional tests performance using a camera-based and machine learning approach.

The objective of this study is to evaluate the performance of functional tests using a camera-based system and machine learning techniques. Specifically, we investigate whether OpenPose and any standard camera can be used to assess the quality of the Single Leg Squat Test and Step Down Test functional tests. We recorded these exercises performed by forty-six healthy subjects, extract motion data, and classify them to expert assessments by three independent physiotherapists using 15 binary parameters. We calculated ranges of movement in Keypoint-pair orientations, joint angles, and relative distances of the monitored segments and used machine learning algorithms to predict the physiotherapists' assessments. Our results show that the AdaBoost classifier achieved a specificity of 0.8, a sensitivity of 0.68, and an accuracy of 0.7. Our findings suggest that a camera-based system combined with machine learning algorithms can be a simple and inexpensive tool to assess the performance quality of functional tests.

Control System of a Lower-Extremity Exoskeleton Based on the Artificial Neural Network.

A lower-extremity exoskeleton can facilitate the lower limbs' rehabilitation by providing additional structural support and strength. This article discusses the design and implementation of a functional prototype of lower extremity brace actuation and its wireless communication control system. The design provides supportive torque and increases the range of motion after complications reducing muscular strength. The control system prototype facilitates elevating a leg, gradually followed by standing and slow walking. The main control modalities are based on an Artificial Neural Network (ANN). The prototype's functionality was tested by time-angle graphs. The final prototype demonstrates the potential application of the ANN in the control system of exoskeletons for joint impairment therapy.

Automatic Telerehabilitation System in a Home Environment Using Computer Vision.

In this paper, we follow up on research dealing with body tracking and motor rehabilitation. We describe the current situation in telerehabilitation in the home environment. Existing solutions do not allow wide adoption due to hardware requirements and complicated setup. We come with the possibility of telerehabilitation using only laptop or mobile web camera. Together with physiotherapists, we have compiled a set of complex motor exercises to show that the system can be practically used.

Evaluation of Postural Stability Differences in the Elderly Through Recurrent Analysis.

Measuring the center of pressure (CoP) for a subject positioned on a force plate is one of the most commonly used tools to investigate balance. Several studies have proven a significant degradation of the body's stability after the age of 60. The conclusions, however, are based on a limited number of indicators and without systematic nonlinear analysis methods being used to evaluate the progression of CoP parameter values. Neither the change in CoP movement in subjects over 60 years of age nor the considerations of their body mass index (BMI) has been systematically evaluated by nonlinear methods so far. This study is based on one of the frequent methods for nonlinear evaluation - the Recurrent Quantification analysis. This article discusses the applicability of this method with regards to the evaluation of changes in postural stability of subjects over 60 years of age. Postural stability changes were evaluated using CoP motion and tested by the nonlinear method. For this research purpose, a group of 103 elderly women were selected and divided into age-respective groups of 60-69 years and 70-79 years old. Each age group was further divided into a subgroup of normal and overweight subjects according to their BMI. The following recurrent analysis parameters were employed in the evaluation of CoP motion in medial-lateral and anterior-posterior directions: determinism (DET), laminarity (LAM) and trapping time (TT). The results of the Wilcoxon test revealed a statistically significant difference between the values in parameters for the different age groups of overweight subjects almost in all the cases. Conversely, statistically significant differences between age groups rarely occurred in a subgroup of subjects with a normal BMI.

Influence of Artificially Generated Interocular Blur Difference on Fusion Stability Under Vergence Stress.

The stability of fusion was evaluated by its breakage when interocular blur differences were presented under vergence demand to healthy subjects. We presumed that these blur differences cause suppression of the more blurred image (interocular blur suppression, IOBS), disrupt binocular fusion and suppressed eye leaves its forced vergent position. During dichoptic presentation of static grayscale images of natural scenes, the luminance contrast (mode B) or higher-spatial frequency content (mode C) or luminance contrast plus higher-spatial frequency content (mode A) were stepwise reduced in the image presented to the non-dominant eye. We studied the effect of these types of blur on fusion stability at various levels of the vergence demand. During the divergence demand, the fusion was disrupted with approximately half blur than during convergence. Various modes of blur influenced fusion differently. The mode C (isolated reduction of higher-spatial frequency content) violated fusion under the lowest vergence demand significantly more than either isolated or combined reduction of luminance contrast (mode B and A). According to our results, the image´s details (i.e. higher-spatial frequency content) protects binocular fusion from disruption by the lowest vergence demand.