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Impedance cardiography (ICG) is an attractive noninvasive method for measuring stroke volume and cardiac output. However, it is easily disturbed by the artifacts such as respiration and body shaking. Considering the correlation between physiological and motion signals, and the synchronization relationship among the physiological signals, this paper introduces an ICG denoising method based on canonical correlation analysis (CCA) and coherence analysis to remove the artifacts during the measurement. First, the CCA extracts the shared components between the electrocardiogram (ECG) and the motion signal, as well as the shared components between ICG and the motion signal. Then, set those shared components to zero to suppress the primary motion artifacts. Next, the coherence analysis was used to calculate the synchronization relationship between obtained ECG and ICG components. Finally, the components with strong synchronization relationships were used to reconstruct the ICG signal. The denoising method was evaluated for 54 subjects during lying and walking. Experimental results show that after removing the artifacts, the signal quality index beat contribution factor (BCF) was increased from the original 78.1% to 97.8%, and the physiological parameters measured based on the proposed method were in good agreement with those measured by the standard instrument. The proposed denoising method effectively improves the reliability of analysis and diagnosis on cardiovascular diseases relying on ICG signals. [ABSTRACT FROM AUTHOR]

Background: Some patients with sepsis are found with accompanying mild hypothermia (ACMH); however, the effects of ACMH on the patients with sepsis are poorly understood.Objective: To compare the impacts of ACMH and artificial mild hypothermia (ATMH) on mortality, systemic inflammatory reactions, and organ functions in mice with sepsis.Methods: Septic mouse models were induced and divided into ACMH, un-hypothermia, keep normothermia, and ATMH groups, according to the anal temperature and the thermic intervention strategy. The mortality rate, serum levels of tumor necrosis factor α (TNF-α), interferon γ (IFN-γ), and interleukin (IL)-4 and liver and renal functions of the mice in each group were recorded. Liver, lung, and renal tissues of the mice were stained and examined under optic microscope.Results: The mortality rate in the ACMH group was the lowest among all the sepsis groups. Increased serum levels of TNF-α, IFN-γ, and IL-4 and impairments of the liver and renal functions were found in the septic mice. The serum levels of TNF-α, IFN-γ, and IL-4 were significantly lower and the liver and renal functions of ACMH group were not impaired significantly as compared with other sepsis groups. Pathological examinations of the lung, liver, and renal tissues showed that the ACMH group were with the lowest pathological score among all the sepsis groups.Conclusion: Accompanying mild hypothermia and ATMH could both reduce mortalities in mice with sepsis, and ACMH could reduce mortality even lower, and more alleviate systemic inflammatory responses and the damages in lung, kidney, and other organs were lighter. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the influence of mild hypothermia on the number of CD11b+ Gr-1+ myeloid-derived suppressor cells (MDSCs) induced by lipopolysaccharide (LPS) injection in mice with sepsis.Methods: BALB/c mice were administered LPS to establish a mouse model of sepsis. Then, these mice were randomly divided into 3 groups: the mild hypothermia plus LPS group, the normothermia plus LPS group, and the LPS group. The normal control group was injected the same amount of 0.9% sodium chloride solution. The ratio of CD11b+ Gr-1+ MDSCs in the mouse spleen and bone marrow was determined at 6, 12, 24, 48, and 72 hours after LPS injection and after injected 0.9% sodium chloride solution.Results: Compared with the control group, the number of MDSCs in the spleen in the sepsis group increased gradually, and the difference was significant at 12 hours after injection (P<.01). Moreover, the number of MDSCs was the lowest in the mild hypothermia group, and there was a significant difference than the other 2 groups at 48 hours (P<.01). The number of MDSCs in the bone marrow increased gradually, and the difference between the sepsis and control groups was significant at 24 hours (P<.01). The number of MDSCs in the mild hypothermia group was the lowest, and there was a statistically significant difference than the other 2 groups (P<.05).Conclusion: Mild hypothermia inhibited the production and accumulation of MDSCs induced by LPS administration in septic mice. [ABSTRACT FROM AUTHOR]

As a non-invasive assisted circulation therapy, enhanced external counterpulsation (EECP) has demonstrated potential in treatment of lower-extremity arterial disease (LEAD). However, the underlying hemodynamic mechanism remains unclear. This study aimed to conduct the first prospective investigation of the EECP-induced responses of blood flow behavior and wall shear stress (WSS) metrics in the femoral artery. Twelve healthy male volunteers were enrolled. A Doppler ultrasound-based approach was introduced for the in vivo determination of blood flow in the common femoral artery (CFA) and superficial femoral artery (SFA) during EECP intervention, with incremental treatment pressures ranging from 10 to 40 kPa. Three-dimensional subject-specific numerical models were developed in 6 subjects to quantitatively assess variations in WSS-derived hemodynamic metrics in the femoral bifurcation. A mesh-independence analysis was performed. Our results indicated that, compared to the pre-EECP condition, both the antegrade and retrograde blood flow volumes in the CFA and SFA were significantly augmented during EECP intervention, while the heart rate remained constant. The time average shear stress (TAWSS) over the entire femoral bifurcation increased by 32.41%, 121.30%, 178.24%, and 214.81% during EECP with treatment pressures of 10 kPa, 20 kPa, 30 kPa, and 40 kPa, respectively. The mean relative resident time (RRT) decreased by 24.53%, 61.01%, 69.81%, and 77.99%, respectively. The percentage of area with low TAWSS in the femoral artery dropped to nearly zero during EECP with a treatment pressure greater than or equal to 30 kPa. We suggest that EECP is an effective and non-invasive approach for regulating blood flow and WSS in lower extremity arteries. [ABSTRACT FROM AUTHOR]