Quantification of Linear and Nonlinear Cardiorespiratory Interactions under Autonomic Nervous System Blockade

This paper proposes a methodology to extract both linear and nonlinear respiratory influences from the heart rate variability (HRV), by decomposing the HRV into a respiratory and a residual component. This methodology is based on least-squares support vector machines (LS-SVM) formulated for nonlinear function estimation. From this decomposition, a better estimation of the respiratory sinus arrhythmia (RSA) and the sympathovagal balance (SB) can be achieved. These estimates are first analyzed during autonomic blockade and an orthostatic maneuver, and then compared against the classical HRV and a model that considers only linear interactions. Results are evaluated using surrogate data analysis and they indicate that the classical HRV and the linear model underestimate the cardiorespiratory interactions. Moreover, the linear and nonlinear interactions appear to be mediated by different control mechanisms. These findings will allow to better assess the ANS and to improve the understanding of the interactions within the cardiorespiratory system

Non-linear analysis of heart rate variability and its application to predict hypotension during spinal anesthesia for cesarean delivery

A non-linear analysis of heart rate variability is carried out through two complexity measures (Correlation Dimension and Pointwise Correlation Dimension) and two regularity measures (Approximate Entropy and Sample Entropy) in order to predict hypotension episodes occurred during spinal anesthesia in cesarean delivery. These methods are applied to RR-interval series, during which woman adopts two alternative positions, one physiologically relaxed (PR) and one physiologically stressed (PS). Results show that women who developed hypotension have significantly higher (p-value = 0.05) complexity measures at PR position, (and significantly lower values for the PS position), than those who did not developed the disease. Regarding the regularity measures, women who developed hypotension have lower values, but not arriving to significance, during PS position than those who did not developed it, whereas those values remain almost constant for PR position

Selective beat averaging to evaluate ventricular repolarization adaptation to deconditioning after 5 days of head-down bed rest

The study of QT/RR relationship is important for the clinical evaluation of possible risk of ventricular tachyarrhythmia. Our aim was to assess the effects of 5-days of head-down (-6 degrees) bed-rest (HDBR) on ventricular repolarization. High fidelity 12-leads Holter ECG was acquired before (PRE), the last day of HDBR (HDT5), and five days after its conclusion (POST). X, Y, Z leads were derived (inverse Dower matrix) and vectorcardiogram computed. Selective beat averaging applied to the night period resulted in averages preceded by the same stable heart rate (for each 10 msec bin amplitude, in the range 900-1200 msec). For each template (i.e., one for each bin), T-wave maximum amplitude (Tmax), T wave area, R-Tapex and R-Tend were computed. Results (in 8 male volunteers) showed that, compared to PRE, at HDT5 both R-Tapex and R-Tend resulted significantly shortened (-5% and -3%, respectively), together with a decrease in T-wave area (-7%), while Tmax was unchanged. At POST, duration parameters showed a trend towards their control values (-1.5% and -3%, respectively) while amplitude parameters resulted restored. Despite the short-term BR, cardiac adaptation to deconditioning affected ventricular repolarization during the night period. © 2012 CCAL

Human emotion characterization by heart rate variability analysis guided by respiration

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksDeveloping a tool which identifies emotions based on their effect on cardiac activity may have a potential impact on clinical practice, since it may help in the diagnosing of psycho-neural illnesses. In this study, a method based on the analysis of heart rate variability (HRV) guided by respiration is proposed. The method was based on redefining the high frequency (HF) band, not only to be centered at the respiratory frequency, but also to have a bandwidth dependent on the respiratory spectrum. The method was first tested using simulated HRV signals, yielding the minimum estimation errors as compared to classical and respiratory frequency centered at HF band based definitions, independently of the values of the sympathovagal ratio. Then, the proposed method was applied to discriminate emotions in a database of video-induced elicitation. Five emotional states, relax, joy, fear, sadness and anger, were considered. The maximum correlation between HRV and respiration spectra discriminated joy vs. relax, joy vs. each negative valence emotion, and fear vs. sadness with p-value = 0.05 and AUC = 0.70. Based on these results, human emotion characterization may be improved by adding respiratory information to HRV analysis.Peer ReviewedPostprint (author's final draft

A comparison of microsecond vs. millisecond dwell times on particle number concentration measurements by single particle ICPMS

With the growing popularity of nanomaterials in a wide variety of products and processes, the need to measure and characterize these materials has also grown. For metallic or metal-containing engineered nanoparticles (NPs), single particle ICP-MS (SP-ICP-MS) has been developed and is growing in popularity due to its ability to rapidly detect and characterize a large number of particles, determine particle size and size distributions, the particle number concentration in a sample, and the elemental mass concentration of both dissolved and particulate species. SP-ICP-MS has been applied to a wide variety of sample types1-5, demonstrating its versatility. A key variable in SP-ICP-MS, which must be applied correctly for accurate measurement of particle concentration, is the dwell time of the ICP-MS. Although this topic has been discussed previously6,7, this work will focus on direct comparisons of results using both microsecond and millisecond dwell times. Since a detailed version of this work is available8, only a brief description will be given here

X-chromosomal haplotype frequencies of four linkage groups in a population of Argentina

DNA samples of hundred ten unrelated anonymized male individuals living in province of Entre Rios, Argentina, were genotyped using Investigador Argus X-12 system (Qiagen) for 12 STRs in four haplogroups. The frequency of most common haplotype was 0.02727, 0.06364, 0.03636, and 0.03636 for haplogroups 1, 2, 3, and 4, respectively. The Match Probability was 6.0E-08 and the mean exclusion chance was 0.999999936. This work presents the first haplotype frequency data for Investigator Argus X-12 system in a population of Argentina

Size determination and quantification of engineered cerium oxide nanoparticles by flow field-flow fractionation coupled to inductively coupled plasma mass spectrometry

Facing the lack of studies on characterization and quantification of cerium oxide nanoparticles (CeO2 NPs), whose consumption and release is greatly increasing, this work proposes a method for their sizing and quantification by Flow Field-flow Fractionation (FFFF) coupled to Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Two modalities of FFFF (Asymmetric Flow- and Hollow Fiber-Flow Field Flow Fractionation, AF4 and HF5, respectively) are compared, and their advantages and limitations discussed. Experimental conditions (carrier composition, pH, ionic strength, crossflow and carrier flow rates) are studied in detail in terms of NP separation, recovery, and repeatability. Size characterization of CeO2 NPs was addressed by different approaches. In the absence of feasible size standards of CeO2 NPs, suspensions of Ag, Au, and SiO2 NPs of known size were investigated. Ag and Au NPs failed to show a comparable behavior to that of the CeO2 NPs, whereas the use of SiO2 NPs provided size estimations in agreement to those predicted by the theory. The latter approach was thus used for characterizing the size of CeO2 NPs in a commercial suspension. Results were in adequate concordance with those achieved by transmission electron microscopy, X-ray diffraction and dynamic light scattering. The quantification of CeO2 NPs in the commercial suspension by AF4-ICP-MS required the use of a CeO2 NPs standards, since the use of ionic cerium resulted in low recoveries (99 ± 9% vs. 73 ± 7%, respectively). A limit of detection of 0.9 µg L-1 CeO2 corresponding to a number concentration of 1.8 × 1012 L-1 for NPs of 5 nm was achieved for an injection volume of 100 µL

Comparison of Antibacterial Activity and Wound Healing in a Superficial Abrasion Mouse Model of Staphylococcus aureus Skin Infection Using Photodynamic Therapy Based on Methylene Blue or Mupirocin or Both

Background: Antibiotic resistance and impaired wound healing are major concerns in S. aureus superficial skin infections, and new therapies are needed. Antimicrobial photodynamic therapy (aPDT) is a new therapeutic approach for infections, but it also improves healing in many wound models. Objective: To compare the antimicrobial activity and the effects on wound healing of aPDT based on Methylene Blue (MB-aPDT) with mupirocin treatment, either alone or in combination, in superficial skin wounds of S. aureus-infected mice. Additionally, to evaluate the clinical, microbiological, and cosmetic effects on wound healing. Materials and Methods: A superficial skin infection model of S. aureus was established in SKH-1 mice. Infected wounds were treated with MB-aPDT, MB-aPDT with a daily topical mupirocin or only with mupirocin. No treatment was carried out in control animals. Daily clinical and microbiological examinations were performed until complete clinical wound healing. Histopathological studies and statistical analysis were performed at the end of the study. Results: MB-aPDT treatment induced the best wound healing compared to mupirocin alone or to mupirocin plus MB-aPDT. Superficial contraction at 24 h and a greater reduction in size at 48 h, quicker detachment of the crust, less scaling, and absence of scars were observed. Histopathological studies correlated with clinical and gross findings. By contrast, mupirocin showed the highest logaritmic reduction of S. aureus. Conclusions: MB-aPDT and mupirocin treatments are effective in a murine superficial skin infection model of S. aureus. One session of MB-aPDT was the best option for clinical wound healing and cosmetic results. The addition of mupirocin to MB-aPDT treatment improved antimicrobial activity; however, it did not enhance wound healing. No synergistic antibacterial effects were detected. © Copyright © 2021 Pérez, Robres, Moreno, Bolea, Verde, Pérez-Laguna, Aspiroz, Gilaberte and Rezusta

Increased circulating microRNAs miR-342-3p and miR-21-5p in natural sheep prion disease

Scrapie is a transmissible spongiform encephalopathy (TSE), or prion disease, of sheep and goats. As no simple diagnostic tests are yet available to detect TSEs in vivo, easily accessible biomarkers could facilitate the eradication of scrapie agents from the food chain. To this end, we analysed by quantitative reverse transcription PCR a selected set of candidate microRNAs (miRNAs) from circulating blood plasma of naturally infected, classical scrapie sheep that demonstrated clear scrapie symptoms and pathology. Significant scrapie-associated increase was repeatedly found for miR-342-3p and miR-21-5p. This is the first demonstration, to our knowledge, of circulating miRNA alterations in any animal suffering from TSE. Genome-wide expression studies are warranted to investigate the true depth of miRNA alterations in naturally occurring TSEs, especially in presymptomatic animals, as the presented study demonstrates the potential feasibility of miRNAs as circulating TSE biomarkers