Kappa-Opioid Receptors in the Caudal Nucleus Tractus Solitarius Mediate 100 Hz Electroacupuncture-Induced Sleep Activities in Rats

Previous results demonstrated that 10 Hz electroacupuncture (EA) of Anmian acupoints in rats during the dark period enhances slow wave sleep (SWS), which involves the induction of cholinergic activity in the caudal nucleus tractus solitarius (NTS) and subsequent activation of opioidergic neurons and μ-receptors. Studies have shown that different kinds of endogenous opiate peptides and receptors may mediate the consequences of EA with different frequencies. Herein, we further elucidated that high-frequency (100 Hz)-EA of Anmian enhanced SWS during the dark period but exhibited no direct effect on rapid eye movement (REM) sleep. High-frequency EA-induced SWS enhancement was dose-dependently blocked by microinjection of naloxone or κ-receptor antagonist (nor-binaltorphimine) into the caudal NTS, but was affected neither by μ- (naloxonazine) nor δ-receptor antagonists (natatrindole), suggesting the role of NTS κ-receptors in the high-frequency EA-induced SWS enhancement. Current and previous results depict the opioid mechanisms of EA-induced sleep

Cascaded Local Implicit Transformer for Arbitrary-Scale Super-Resolution

Implicit neural representation has recently shown a promising ability in representing images with arbitrary resolutions. In this paper, we present a Local Implicit Transformer (LIT), which integrates the attention mechanism and frequency encoding technique into a local implicit image function. We design a cross-scale local attention block to effectively aggregate local features. To further improve representative power, we propose a Cascaded LIT (CLIT) that exploits multi-scale features, along with a cumulative training strategy that gradually increases the upsampling scales during training. We have conducted extensive experiments to validate the effectiveness of these components and analyze various training strategies. The qualitative and quantitative results demonstrate that LIT and CLIT achieve favorable results and outperform the prior works in arbitrary super-resolution tasks

Subcutaneous nerve activity is more accurate than heart rate variability in estimating cardiac sympathetic tone in ambulatory dogs with myocardial infarction

BACKGROUND: We recently reported that subcutaneous nerve activity (SCNA) can be used to estimate sympathetic tone. OBJECTIVE: The purpose of this study was to test the hypothesis that left thoracic SCNA is more accurate than heart rate variability (HRV) in estimating cardiac sympathetic tone in ambulatory dogs with myocardial infarction (MI). METHODS: We used an implanted radiotransmitter to study left stellate ganglion nerve activity (SGNA), vagal nerve activity (VNA), and thoracic SCNA in 9 dogs at baseline and up to 8 weeks after MI. HRV was determined based on time-domain, frequency-domain, and nonlinear analyses. RESULTS: The correlation coefficients between integrated SGNA and SCNA averaged 0.74 (95% confidence interval [CI] 0.41-1.06) at baseline and 0.82 (95% CI, 0.63-1.01) after MI (P <.05 for both). The absolute values of the correlation coefficients were significantly larger than that between SGNA and HRV analysis based on time-domain, frequency-domain, and nonlinear analyses, respectively, at baseline (P <.05 for all) and after MI (P <.05 for all). There was a clear increment of SGNA and SCNA at 2, 4, 6, and 8 weeks after MI, whereas HRV parameters showed no significant changes. Significant circadian variations were noted in SCNA, SGNA, and all HRV parameters at baseline and after MI, respectively. Atrial tachycardia (AT) episodes were invariably preceded by SCNA and SGNA, which were progressively increased from 120th, 90th, 60th, to 30th seconds before AT onset. No such changes of HRV parameters were observed before AT onset. CONCLUSION: SCNA is more accurate than HRV in estimating cardiac sympathetic tone in ambulatory dogs with MI

Small Conductance Calcium-Activated Potassium Current is Activated During Hypokalemia and Masks Short Term Cardiac Memory Induced by Ventricular Pacing.

Background: Hypokalemia increases the vulnerability to ventricular fibrillation (VF). We hypothesize that the apamin-sensitive small conductance calcium-activated potassium current (IKAS) is activated during hypokalemia and that IKAS blockade is proarrhythmic. Methods and Results: Optical mapping was performed in 23 Langendorff perfused rabbit ventricles with atrioventricular block and either right ventricular (RV) or left ventricular (LV) pacing during normokalemia or hypokalemia. Apamin prolonged the action potential duration (APD) measured to 80% repolarization (APD80) by 26 ms [95% confidence interval, CI, 14–37] during normokalemia and by 54 ms [CI, 40 to 68] during hypokalemia (P=0.01) at 1000 ms pacing cycle length (PCL). In hypokalemic ventricles, apamin increased the maximal slope of APD restitution, the PCL threshold of APD alternans, the PCL for wavebreak induction and the area of spatially discordant APD alternans. Apamin significantly facilitated the induction of sustained VF (from 3/9 hearts to 9/9 hearts, P=0.009). Short term cardiac memory was assessed by the slope of APD80 versus activation time. The slope increased from 0.01 [CI, −0.09 to 0.12] at baseline to 0.34 [CI, 0.23 to 0.44] after apamin (P<0.001) during RV pacing, and from 0.07 [CI, −0.05 to 0.20] to 0.54 [CI, 0.06 to 1.03] after apamin infusion (P=0.045) during LV pacing. Patch-clamp studies confirmed increased IKASin isolated rabbit ventricular myocytes during hypokalemia (P=0.038). Conclusions: Hypokalemia activates IKAS to shorten APD and maintain repolarization reserve at late activation sites during ventricular pacing. IKAS blockade prominently lengthens the APD at late activation sites and facilitates VF induction

Multi-scale symbolic entropy analysis provides prognostic prediction in patients receiving extracorporeal life support

Introduction: Extracorporeal life support (ECLS) can temporarily support cardiopulmonary function, and is occasionally used in resuscitation. Multi-scale entropy (MSE) derived from heart rate variability (HRV) is a powerful tool in outcome prediction of patients with cardiovascular diseases. Multi-scale symbolic entropy analysis (MSsE), a new method derived from MSE, mitigates the effect of arrhythmia on analysis. The objective is to evaluate the prognostic value of MSsE in patients receiving ECLS. The primary outcome is death or urgent transplantation during the index admission. Methods: Fifty-seven patients receiving ECLS less than 24 hours and 23 control subjects were enrolled. Digital 24-hour Holter electrocardiograms were recorded and three MSsE parameters (slope 5, Area 6–20, Area 6–40) associated with the multiscale correlation and complexity of heart beat fluctuation were calculated. Results: Patients receiving ECLS had significantly lower value of slope 5, area 6 to 20, and area 6 to 40 than control subjects. During the follow-up period, 29 patients met primary outcome. Age, slope 5, Area 6 to 20, Area 6 to 40, acute physiology and chronic health evaluation II score, multiple organ dysfunction score (MODS), logistic organ dysfunction score (LODS), and myocardial infarction history were significantly associated with primary outcome. Slope 5 showed the greatest discriminatory power. In a net reclassification improvement model, slope 5 significantly improved the predictive power of LODS; Area 6 to 20 and Area 6 to 40 significantly improved the predictive power in MODS. In an integrated discrimination improvement model, slope 5 added significantly to the prediction power of each clinical parameter. Area 6 to 20 and Area 6 to 40 significantly improved the predictive power in sequential organ failure assessment. Conclusions: MSsE provides additional prognostic information in patients receiving ECLS. Electronic supplementary material The online version of this article (doi:10.1186/s13054-014-0548-3) contains supplementary material, which is available to authorized users

Lessons Learned of NSPO’s Picosatellite Mission: Yamsat - 1A, 1B & 1C

The YamSat is the first developed picosatellite in National Space Program Office’s (NSPO), Taiwan, R.O.C. It is scheduled to flight in the CubeSat launch in 2003. The rapid-prototyping system engineering different from the past formal discipline opens a new satellite development model in NSPO. The YamSat Test Readiness Review Meeting was successfully held in January 2002 and the environmental tests were completed by end March 2002. Besides the breadboard model and engineering test bed to prove of operation concept are built, three YamSats (1A, 1B, & 1C) instead of one are manufactured with slightly different configurations and purposes. The YamSat- 1A is for flight with ambitious and novel R.O.C. made components, including 15 domestic organizations and companies’ participation. The YamSat-1B is basically for backup purpose and demonstration, whereas the YamSat-1C is for amateur communication experiment end-to-end field test, and for public education purpose. This new experience gives fruitful lessons learned and provides low cost space experimentation and education to the next built picosatellites in Taiwan’s universities. Detailed mission and lessons learned are addressed in this paper

Biomechanical investigation of flexor digitorum tendons in trigger finger patients using sonography

Trigger finger (TF) has generally been ascribed to primary changes in the first annular (A1) pulley. Repeated friction between the A1 pulley and flexor digitorum tendons could result in swelling of soft tissues, and thus it has been speculated that TF affects tendons’ biomechanical behaviors. However, the pathology mechanism related to these behaviors remains unclear. The purposes of this study are to understand (1) the variations in the morphologies of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) between normal fingers and TFs, (2) the differences in the biomechanical behaviors of the FDP and FDS between normal fingers and TFs in various finger flexion positions, and (3) the effect of various finger positions on the biomechanical behaviors of the FDP and FDS

Role of Apamin-Sensitive Calcium-Activated Small-Conductance Potassium Currents on the Mechanisms of Ventricular Fibrillation in Pacing-Induced Failing Rabbit Hearts

BACKGROUND: Ventricular fibrillation (VF) during heart failure is characterized by stable reentrant spiral waves (rotors). Apamin-sensitive small-conductance calcium-activated potassium currents (IKAS) are heterogeneously upregulated in failing hearts. We hypothesized that IKAS influences the location and stability of rotors during VF. METHODS AND RESULTS: Optical mapping was performed on 9 rabbit hearts with pacing-induced heart failure. The epicardial right ventricular and left ventricular surfaces were simultaneously mapped in a Langendorff preparation. At baseline and after apamin (100 nmol/L) infusion, the action potential duration (APD80) was determined, and VF was induced. Areas with a >50% increase in the maximum action potential duration (ΔAPD) after apamin infusion were considered to have a high IKAS distribution. At baseline, the distribution density of phase singularities during VF in high IKAS distribution areas was higher than in other areas (0.0035±0.0011 versus 0.0014±0.0010 phase singularities/pixel; P=0.004). In addition, high dominant frequencies also colocalized to high IKAS distribution areas (26.0 versus 17.9 Hz; P=0.003). These correlations were eliminated during VF after apamin infusion, as the number of phase singularities (17.2 versus 11.0; P=0.009) and dominant frequencies (22.1 versus 16.2 Hz; P=0.022) were all significantly decreased. In addition, reentrant spiral waves became unstable after apamin infusion, and the duration of VF decreased. CONCLUSIONS: The IKAS current influences the mechanism of VF in failing hearts as phase singularities, high dominant frequencies, and reentrant spiral waves all correlated to areas of high IKAS. Apamin eliminated this relationship and reduced VF vulnerability