The first aim of this study was to compare an ambulatory five-lead ECG system with the commercially available breast belt measuring devices; Polar S810i and Suunto t6, in terms of R-R interval measures and heart rate variability (HRV) indices. The second aim was to compare different HRV spectral analysis methods. Nineteen young males (aged between 22 and 31 years, median 24 years) underwent simultaneous R-R interval recordings with the three instruments during supine and sitting rest, moderate dynamic, and moderate to vigorous static exercise of the upper and lower limb. For each subject, 17 R-R interval series of 3-min length were extracted from the whole recordings and then analyzed in frequency domain using (1) a fast Fourier transform (FFT), (2) an autoregressive model (AR), (3) a Welch periodogram (WP) and (4) a continuous wavelet transform (CWT). Intra-class correlation coefficients (ICC) and Bland-Altman limits of agreement (LoA) method served as criteria for measurement agreement. Regarding the R-R interval recordings, ICC (lower ICC 95% confidence interval >0.99) as well as LoA (maximum LoA: -15.1 to 14.3 ms for ECG vs. Polar) showed an excellent agreement between all devices. Therefore, the three instruments may be used interchangeably in recording and interpolation of R-R intervals. ICCs for HRV frequency parameters were also high, but in most cases LoA analysis revealed unacceptable discrepancies between the instruments. The agreement among the different frequency transform methods can be taken for granted when analyzing the normalized power in low and high frequency ranges; however, not when analyzing the absolute values.
The diagnostic performance of multifrequency MR elastography in determining the degree of hepatic fibrosis increases with stage of fibrosis. Metrics obtained at the higher frequencies provide better diagnostic performance compared with the lower frequencies. Results of the AUROC analysis demonstrate the high accuracy of frequency-independent cutoff values for staging higher grades of hepatic fibrosis.
Objective: Adipose tissue-derived factors link non-alcoholic fatty liver disease (NAFLD) with obesity, which has also been reported for circulating chemerin. On the other hand, hepatic chemerin and chemokine-like receptor 1 (CMKLR1) mRNA expression has not yet been studied in an extensively characterized patient collective. Design: This study was cross-sectional and experimental in design. Methods: Liver tissue samples were harvested from 47 subjects and histologically examined according to the NAFLD activity score (NAS). The concentrations of chemerin and CMKLR1 were measured using semi-quantitative real-time PCR, and the concentration of serum chemerin was measured using ELISA. To evaluate potential effects of chemerin and CMKLR1, cultured primary human hepatocytes (PHHs) were exposed to selected metabolites known to play a role in NAFLD (insulin, glucagon, palmitoic acid, and interleukin-6 (IL6)). Results: Chemerin and CMKLR1 mRNA levels were elevated in the human liver. Their expression was correlated with the NAS (R 2 Z0.543; P!0.001 and R 2 Z0.355; PZ0.014 respectively) and was significantly elevated in patients with definite non-alcoholic steatohepatitis (NASH) (P!0.05 respectively). Linear regression analysis confirmed an independent association of liver fibrosis, steatosis, inflammation, and hepatocyte ballooning with hepatic chemerin mRNA expression (P!0.05 respectively). The expression of hepatic chemerin and CMKLR1 was correlated with the measures of obesity (P!0.05). The incubation of PHHs with IL6 significantly increased the expression of CMKLR1 mRNA (PZ0.027), while that of chemerin remained unaffected (PO0.05). None of the other metabolites showed an influence (PO0.05). Conclusion: This is the first study to show that chemerin mRNA expression is significantly elevated in the liver of NASH patients and that CMKLR1 expression is upregulated in liver inflammation, whereby IL6 could play a causal role.
Our results reveal that higher perceived stress in the operating room is associated with increased intraoperative HR and decreased HRV at night. Non-stressed surgeons show greater relaxation during sleep compared to their stressed colleagues.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.