Heart rate variability (HRV) and muscular system activity (EMG) in cases of crash threat during simulated driving of a passenger car

Objectives: The aim of the study was to verify whether simultaneous responses from the muscular and circulatory system occur in the driver's body under simulated conditions of a crash threat. Materials and Methods: The study was carried out in a passenger car driving simulator. The crash was included in the driving test scenario developed in an urban setting. In the group of 22 young male subjects, two physiological signals - ECG and EMG were continuously recorded. The length of the RR interval in the ECG signal was assessed. A HRV analysis was performed in the time and frequency domains for 1-minute record segments at rest (seated position), during undisturbed driving as well as during and several minutes after the crash. For the left and right side muscles: m. trapezius (TR) and m. flexor digitorum superficialis (FDS), the EMG signal amplitude was determined. The percentage of maximal voluntary contraction (MVC) was compared during driving and during the crash. Results: As for the ECG signal, it was found that in most of the drivers changes occurred in the parameter values reflecting HRV in the time domain. Significant changes were noted in the mean length of RR intervals (mRR). As for the EMG signal, the changes in the amplitude concerned the signal recorded from the FDS muscle. The changes in ECG and EMG were simultaneous in half of the cases. Conclusion: Such parameters as mRR (ECG signal) and FDS-L amplitude (EMG signal) were the responses to accident risk. Under simulated conditions, responses from the circulatory and musculoskeletal systems are not always simultaneous. The results indicate that a more complete driver's response to a crash in road traffic is obtained based on parallel recording of two physiological signals (ECG and EMG)

Liver-Specific Commd1 Knockout Mice Are Susceptible to Hepatic Copper Accumulation

Canine copper toxicosis is an autosomal recessive disorder characterized by hepatic copper accumulation resulting in liver fibrosis and eventually cirrhosis. We have identified COMMD1 as the gene underlying copper toxicosis in Bedlington terriers. Although recent studies suggest that COMMD1 regulates hepatic copper export via an interaction with the Wilson disease protein ATP7B, its importance in hepatic copper homeostasis is ill-defined. In this study, we aimed to assess the effect of Commd1 deficiency on hepatic copper metabolism in mice. Liver-specific Commd1 knockout mice (Commd1Δhep) were generated and fed either a standard or a copper-enriched diet. Copper homeostasis and liver function were determined in Commd1Δhep mice by biochemical and histological analyses, and compared to wild-type littermates. Commd1Δhep mice were viable and did not develop an overt phenotype. At six weeks, the liver copper contents was increased up to a 3-fold upon Commd1 deficiency, but declined with age to concentrations similar to those seen in controls. Interestingly, Commd1Δhep mice fed a copper-enriched diet progressively accumulated copper in the liver up to a 20-fold increase compared to controls. These copper levels did not result in significant induction of the copper-responsive genes metallothionein I and II, neither was there evidence of biochemical liver injury nor overt liver pathology. The biosynthesis of ceruloplasmin was clearly augmented with age in Commd1Δhep mice. Although COMMD1 expression is associated with changes in ATP7B protein stability, no clear correlation between Atp7b levels and copper accumulation in Commd1Δhep mice could be detected. Despite the absence of hepatocellular toxicity in Commd1Δhep mice, the changes in liver copper displayed several parallels with copper toxicosis in Bedlington terriers. Thus, these results provide the first genetic evidence for COMMD1 to play an essential role in hepatic copper homeostasis and present a valuable mouse model for further understanding of the molecular mechanisms underlying hepatic copper homeostasis

Computational Methods Used in Hit-to-Lead and Lead Optimization Stages of Structure-Based Drug Discovery

GPCR modeling approaches are widely used in the hit-to-lead (H2L) and lead optimization (LO) stages of drug discovery. The aims of these modeling approaches are to predict the 3D structures of the receptor-ligand complexes, to explore the key interactions between the receptor and the ligand and to utilize these insights in the design of new molecules with improved binding, selectivity or other pharmacological properties. In this book chapter, we present a brief survey of key computational approaches integrated with hierarchical GPCR modeling protocol (HGMP) used in hit-to-lead (H2L) and in lead optimization (LO) stages of structure-based drug discovery (SBDD). We outline the differences in modeling strategies used in H2L and LO of SBDD and illustrate how these tools have been applied in three drug discovery projects

Musculoskeletal load and disorders and workers' knowledge about the ergonomics of a computer workstand

Podczas wykonywania pracy biurowej na stanowisku komputerowym często dochodzi do nadmiernego obciążenia i zmęczenia mięśni, co może prowadzić do powstawania dolegliwości układu mięśniowo-szkieletowego. Dlatego też, zarówno badanie występowania tych dolegliwości, jak również ocena obciążenia na stanowisku pracy mają bardzo duże znaczenie. W artykule przedstawiono wyniki badań dotyczących występowania dolegliwości mięśniowo-szkieletowych oraz wyniki oceny obciążenia mięśniowo-szkieletowego, występującego na stanowiskach pracy z komputerem.Office work performed at a computer workstand often leads to excessive muscle load and muscle fatigue, which may cause musculoskeletal disorders. That is why it is important to assess the presence of musculoskeletal disorders and of load during occupational tasks. This article presents the results of research on musculoskeletal disorders and of an assessment of musculoskeletal load at computer workstands

The influence of muscle type on EMG power spectrum parameters

Celem pracy było opracowanie wskaźników, opartych na widmie mocy sygnału elektromiograficznego (EMG), obrazujących budowę morfologiczną mięśnia. Sygnał EMG został zarejestrowany z mięśni: czworoboczny część zstępująca (trapezius pars descendens-TPD), naramienny część obojczykowa (deltoideus pars clavicularis-DPC), naramienny część barkowa (deltoideus pars acromialis-DPA) oraz zginacz łokciowy nadgarstka (flexor carpi ulnaris-FCU), podczas badań w 6 wariantach obciążenia. W wyniku analizy opracowano parametry widma mocy sygnału EMG, szczególnie wrażliwe na zmiany w strukturze mięśnia.The aim of this study was to develop coefficients of electromyographic (EMG) signal, which show the morphological properties of muscle. Measurements of EMG signal from muscles: trapezius pars descendens (TPD), deltoideus pars clavicularis (DPC), deltoideus pars acromialis (DPA) and flexor carpi ulnaris (FCU), during research in 6 variants of load were realized. As the result of analysis the parameters based on power spectrum of EMG signal were worked out. Differences between morphological structure of muscle can be described using these parameters

Evaluating musculoskeletal load and the aging of employees

W artykule przedstawiono zjawisko starzenia się społeczeństwa oraz związane z tym problemy, a także omówiono wpływ starzenia się na procesy zachodzące w mięśniach. Zaprezentowano także sposób oceny obciążenia i zmęczenia układu mięśniowo-szkieletowego, z zastosowaniem elektromiografii powierzchniowej (EMG), uwzględniającej wiek i płeć pracownika.This article discusses the phenomenon of the aging society and related problems as well as the impact of aging on processes taking place in human muscles. It also presents a method of evaluating musculoskeletal load and fatigue with the use of surface electromyography (EMG), taking into account the worker's age and gender

Assessment of muscle load and fatigue with the usage of frequency and time-frequency analysis of the EMG signal

The aim of the study was to determine the effect of the muscle load and fatigue on the values of the parameters calculated on the basis of the time, frequency (Fourier transform) and time-frequency (wavelet transform) analysis of the EMG signal, for low levels of load. Fifteen young men took part in the study. The EMG signal was registered from right side biceps brachii (BB) and trapezius (TR) muscles in static conditions, at load 10%, 20% and 30% MVC (maximal voluntary contraction). On the basis of the analysis there were selected parameters sensitive to force (RMS) and parameters sensitive to fatigue but simultaneously insensitive to force (MPF – mean power frequency determined on the basis of Fourier transform, CMPFdb5 – mean power frequency determined on the basis of the wavelet transform). The results indicate that CMPFdb5 can show similar (muscle BB) or greater (muscle TR) sensitivity to fatigue than MPF. It can suggest that, for low levels of load, the wavelet transform parameters can be more effective in assessing muscle fatigue than the parameters based on the Fourier transform. The obtained results can allow for a more precise analysis of muscle fatigue at low levels of load. Further analysis for a greater number of muscles activated at low levels of load, with the usage of the parameters tested is desirable