ABSTRACT
BACKGROUND@#Hypobaric hypoxia (HH) exposure at high altitudes can result in a decline in cognitive function, which may have a serious impact on the daily life of people who migrate to high altitudes. However, the specific HH-induced changes in brain function remain unclear. This study explored changes in brain activity in rats exposed to a sustained HH environment using functional magnetic resonance imaging (fMRI).@*METHODS@#Healthy male rats (8 weeks old) were randomly divided into a model group and a control group. A rat model of cognitive impairment induced by sustained HH exposure was established. The control and model groups completed training and testing in the Morris water maze (MWM). A two-sample t-test for between-group difference comparisons was performed. Repeated measures analyses of variance for within-group comparisons were performed and post-hoc comparisons were made using the Tukey test. Between-group differences in spontaneous brain activity were assessed using a voxel-wise analysis of resting-state fMRI (rs-fMRI), combined with analyses of the fractional amplitude of low frequency fluctuations (fALFF) in statistical parametric mapping.@*RESULTS@#In the MWM test, the escape latencies of the model group were significantly longer compared with those of the control group (control group vs. model group, day 1: 21.6 ± 3.3 s vs. 40.5 ± 3.4 s, t = -11.282; day 2: 13.5 ± 2.2 s vs. 28.7 ± 5.3 s, t = -7.492; day 3: 10.5 ± 2.8 s vs. 22.6 ± 6.1 s, t = -5.099; day 4: 9.7 ± 2.5 s vs. 18.6 ± 5.2 s, t = -4.363; day 5: 8.8 ± 2.7 s vs. 16.7 ± 5.0 s, t = -3.932; all P < 0.001). Within both groups, the escape latency at day 5 was significantly shorter than those at other time points (control group: F = 57.317, P < 0.001; model group: F = 50.718, P < 0.001). There was no within-group difference in average swimming speed (control group, F = 1.162, P = 0.956; model group, F = 0.091, P = 0.880). Within the model group, the time spent within the original platform quadrant was significantly shorter (control group vs. model group: 36.1 ± 5.7 s vs. 17.8 ± 4.3 s, t = 7.249, P < 0.001) and the frequency of crossing the original platform quadrant was significantly reduced (control group vs. model group: 6.4 ± 1.9 s vs. 2.0 ± 0.8 s, t = 6.037, P < 0.001) compared with the control group. In the rs-fMRI study, compared with the control group, rats in the model group showed widespread reductions in fALFF values throughout the brain.@*CONCLUSIONS@#The abnormalities in spontaneous brain activity indicated by the fALFF measurements may reflect changes in brain function after HH exposure. This widespread abnormal brain activity may help to explain and to provide new insights into the mechanism underlying the impairment of brain function under sustained exposure to high altitudes.
ABSTRACT
Background@#Hypobaric hypoxia (HH) exposure at high altitudes can result in a decline in cognitive function, which may have a serious impact on the daily life of people who migrate to high altitudes. However, the specific HH-induced changes in brain function remain unclear. This study explored changes in brain activity in rats exposed to a sustained HH environment using functional magnetic resonance imaging (fMRI).@*Methods@#Healthy male rats (8 weeks old) were randomly divided into a model group and a control group. A rat model of cognitive impairment induced by sustained HH exposure was established. The control and model groups completed training and testing in the Morris water maze (MWM). A two-sample t-test for between-group difference comparisons was performed. Repeated measures analyses of variance for within-group comparisons were performed and post-hoc comparisons were made using the Tukey test. Between-group differences in spontaneous brain activity were assessed using a voxel-wise analysis of resting-state fMRI (rs-fMRI), combined with analyses of the fractional amplitude of low frequency fluctuations (fALFF) in statistical parametric mapping.@*Results@#In the MWM test, the escape latencies of the model group were significantly longer compared with those of the control group (control group vs. model group, day 1: 21.6 ± 3.3 s vs. 40.5 ± 3.4 s, t = -11.282; day 2: 13.5 ± 2.2 s vs. 28.7 ± 5.3 s, t = -7.492; day 3: 10.5 ± 2.8 s vs. 22.6 ± 6.1 s, t = -5.099; day 4: 9.7 ± 2.5 s vs. 18.6 ± 5.2 s, t = -4.363; day 5: 8.8 ± 2.7 s vs. 16.7 ± 5.0 s, t = -3.932; all P < 0.001). Within both groups, the escape latency at day 5 was significantly shorter than those at other time points (control group: F = 57.317, P < 0.001; model group: F = 50.718, P < 0.001). There was no within-group difference in average swimming speed (control group, F = 1.162, P = 0.956; model group, F = 0.091, P = 0.880). Within the model group, the time spent within the original platform quadrant was significantly shorter (control group vs. model group: 36.1 ± 5.7 s vs. 17.8 ± 4.3 s, t = 7.249, P < 0.001) and the frequency of crossing the original platform quadrant was significantly reduced (control group vs. model group: 6.4 ± 1.9 s vs. 2.0 ± 0.8 s, t = 6.037, P < 0.001) compared with the control group. In the rs-fMRI study, compared with the control group, rats in the model group showed widespread reductions in fALFF values throughout the brain.@*Conclusions@#The abnormalities in spontaneous brain activity indicated by the fALFF measurements may reflect changes in brain function after HH exposure. This widespread abnormal brain activity may help to explain and to provide new insights into the mechanism underlying the impairment of brain function under sustained exposure to high altitudes.
ABSTRACT
This paper introduces the design and implementation of a novel respiratory detecting system based on bio-impedance method. By increasing electrodes in space, the system make multi-channel respiratory signals be superpositioned and filtered (SNR); Traditional filter methods by both hardware and software are also used to further increase anti-interference ability. A low consumption and portable instrument is designed based on MSP430 Micro Controller Unit (MCU), The experiment shows a better performance in the reduction of interference noises of heartbeat and blood flow especially the motion artifact. Also the system works stably.
Subject(s)
Electric Impedance , Electrodes , Respiratory Function Tests , Methods , SoftwareABSTRACT
This article describes the design of a sensor vest and its corresponding measuring and transfering system which can be used for ECG and respiration monitoring in mobile and noninvasive conditions. The electric conduction textile is sutured in the inside of the vest in its specific position to be detecting electrodes, which are connected to the vest edge. The signal is then connected to the measuring and transferring system. in which the microcontroller and circuits monitor the ECG, heart rate and respiration data. The data are transmitted through the serial communication to a PC, and then are received and displayed with Visual Basic program.
Subject(s)
Clothing , Diagnosis, Computer-Assisted , Electrocardiography, Ambulatory , Equipment Design , Monitoring, Ambulatory , Respiration , Signal Processing, Computer-Assisted , Telecommunications , TextilesABSTRACT
This article describes a method totransfer physiological data through carrier-current communication.The microcontroller measures the data of heartrate and body temperature and sends them through the serial port tothe carrier-current module implementing carrier-current communication.This method can be used totransfer physiological data through short distance less than200meters.
ABSTRACT
To study the expression of HCV non-structure 5 antigen in vitro, a human HepG2 cell line was incubated with a HCV RNA positive serum. The S ABC i mmunological techniques and gold-labeled colloid electron microscopy method wer e employed to examine for the viral proteins in those cells. The HCV non-struct ure 5 antigen was first detected in the HepG2 cells at 72 hours post incubation. The antigen was continuously observed in the cytoplasm or on the membrane as we ll on the cell wall of the HepG2 cells even after 1, 2, 3 and 4 weeks post incub ation. The observation of HCV non-structure 5 antigen continuously expressed in the HepG2 cells strongly indicates that the cells may have been infected by HCV virus and the virus may have replicated in the cells. Therefore, the HepG2 cell line may be served as a potential host for establishment of HCV infection and p ropagation in vitro.