Validity Verification of Human Pose-Tracking Algorithms for Gait Analysis Capability.

Two-dimensional (2D) clinical gait analysis systems are more affordable and portable than contemporary three-dimensional (3D) clinical models. Using the Vicon 3D motion capture system as the standard, we evaluated the internal statistics of the Imasen and open-source OpenPose gait measurement systems, both designed for 2D input, to validate their output based on the similarity of results and the legitimacy of their inner statistical processes. We measured time factors, distance factors, and joint angles of the hip and knee joints in the sagittal plane while varying speeds and gaits during level walking in three in-person walking experiments under normal, maximum-speed, and tandem scenarios. The intraclass correlation coefficients of the 2D models were greater than 0.769 for all gait parameters compared with those of Vicon, except for some knee joint angles. The relative agreement was excellent for the time-distance gait parameter and moderate-to-excellent for each gait motion contraction range, except for hip joint angles. The time-distance gait parameter was high for Cronbach's alpha coefficients of 0.899-0.993 but low for 0.298-0.971. Correlation coefficients were greater than 0.571 for time-distance gait parameters but lower for joint angle parameters, particularly hip joint angles. Our study elucidates areas in which to improve 2D models for their widespread clinical application.

Peripheral-central network analysis of cancer cachexia status accompanied by the polarization of hypothalamic microglia with low expression of inhibitory immune checkpoint receptors.

While the excessive inflammation in cancer cachexia is well-known to be induced by the overproduction of inflammatory mediators in the periphery, microflora disruption and brain dysfunction are also considered to contribute to the induction of cancer cachexia. Hypothalamic microglia play a crucial role in brain inflammation and central-peripheral immune circuits via the production of inflammatory mediators. In the present study, we evaluated possible changes in excessive secretion of gut microbiota-derived endotoxin and the expression timeline of several inflammation-regulatory mediators and their inhibiting modulators in hypothalamic microglia of a mouse model of cancer cachexia following transplantation of pancreatic cancer cells. We demonstrated that the plasma level of lipopolysaccharide (LPS) was significantly increased with an increase in anaerobic bacteria, especially Firmicutes, in the gut at the late stage of tumor-bearing mice that exhibited dramatic appetite loss, sarcopenia and severe peripheral immune suppression. At the early stage, in which tumor-bearing mice had not yet displayed "cachexia symptoms", the mRNA expression of pro-inflammatory cytokines, but not of the neurodegenerative and severe inflammatory modulator lipocalin-2 (LCN2), was significantly increased, whereas at the late "cachexia stage", the level of LCN2 mRNA was significantly increased along with significant decreases in levels of inhibitory immune checkpoint receptors programmed death receptor-1 (PD-1) and CD112R in hypothalamic microglia. In addition, a high density of activated neurons in the paraventricular nucleus (PVN) of the hypothalamus region and a significant increase in corticosterone secretion were found in cachexia model mice. Related to the cachexia state, released corticosterone was clearly increased in normal mice with specific activation of PVN neurons. A marked decrease in the natural killer cell population was also observed in the spleen of mice with robust activation of PVN neurons as well as mice with cancer cachexia. On the other hand, in vivo administration of LPS in normal mice induced hypothalamic microglia with low expression of inhibitory immune checkpoint receptors. These findings suggest that the induction of cancer cachexia may parallel exacerbation of the hypothalamic inflammatory status with polarization to microglia expressed with low levels of inhibitory immune checkpoint receptors following LPS release from the gut microflora.

Factor analysis for construct validity of a trunk impairment scale in Parkinson's disease: a cross-sectional study.

Objectives: To investigate the construct validity of the Trunk Impairment Scale (TIS), which was developed to assess trunk impairment in patients with stroke, in patients with Parkinson's disease (PD). Design: This retrospective, cross-sectional study enrolled consecutive PD inpatients. Correlation analysis was performed to clarify whether the TIS assessment was related to other balance functions, lower extremity muscle strength, or walking ability. Factor analysis was performed to see how the background factors of TIS differ from balance function, lower limb muscle strength, and walking ability. Results: Examining the data of 471 patients with PD, there were relationships between TIS and the Mini-Balance Evaluation Systems Test (r = 0.67), Barthel Index (r = 0.57), general lower limb extension torque (r = 0.51), two-minute walk test (r = 0.54), Hoehn and Yahr stage (r = -0.61), and Movement Disorder Society Unified Parkinson's Disease Rating Scale part III total points (r = -0.59). Factor analysis showed that TIS items were divided into three factors (an abdominal muscles and righting reflex component; a perception and verticality component; and a rotational component), differing from other scales that included clinical assessment items. Conclusion: The TIS can be useful for assessing the underlying trunk impairment as a basis for activities of daily living, gait function, and balance ability in patients with PD.

Correlation Between Skin Autofluorescence and Muscle Activities of Lower Limb in Aging Without Disease and Disability.

Skin autofluorescence is a useful index to estimate the accumulation of advanced glycation end-products in human tissues. Elderly persons with higher skin autofluorescence have lower muscle mass, muscle strength and muscle power, however, little is known about the relationship between the skin autofluorescence level and each muscle activity. We measured the values of skin autofluorescence from five places on a lower limb, and the signals of surface electromyogram during isometric contractions from five muscles on that, simultaneously. The waveforms of surface electromyogram were analyzed by Daubechies-4 wavelet transformation. The value of skin autofluorescence was increased in the proximal part of the lower limb compared with the value of the distal part. The principal component of surface electromyogram activity in a time-frequency domain was lower in the proximal part compared with that of the distal part. There was a weak negative correlation between the value of skin autofluorescence on the gluteal region and the value of the mean wavelet coefficient of the surface electromyogram signals within the gluteus maximus muscle. The higher accumulation of advanced glycation end-products on the gluteal region might suggest the lower muscle activity in aging without disease and disability.

Effects of restriction of forefoot rocker functions by immobilisation of metatarsophalangeal joints on kinematics and kinetics during walking.

OBJECTIVE: This study was conducted to investigate the effects of restriction of forefoot rocker (FFR) functions by immobilisation of unilateral metatarsophalangeal joints (MPJs) on kinematic and kinetic factors during walking. METHODS: Eighteen healthy young adults participated in this study. To immobilise the MPJs of the right leg, an aluminium sole plate (AS) was fixed on the sole of the foot. Kinematic and kinetic data were collected while each subject walked at a comfortable speed with the AS and without. RESULTS: In the AS condition, the walking speed and contralateral step length were significantly decreased, and an asymmetrical centre of mass (COM) movement was observed. The range of plantarflexion motion and positive work by the ankle joint were decreased markedly during the late stance of the AS limb. In contrast, maximum hip and knee flexion angles in the swing phase of the AS limb and positive work by the bilateral hip joints over the gait cycle were increased. CONCLUSIONS: The results suggested that MPJ immobilisation may result in marked motion limitation of ankle plantarflexion and inhibition of push-off by the ankle joint despite no restrictions on the ankle joint. These changes may interfere with gait speed and a smooth and symmetrical COM shift during walking.

Characteristics of Lower Limb Muscle Activity in Elderly Persons After Ergometric Exercise.

This study examined the characteristics of lower limb muscle activity in elderly persons after ergometric pedaling exercise for 1 month. To determine the effect of the exercise, surface electromyography (SEMG) of lower limb muscles was subjected to Daubechies-4 wavelet transformation, and mean wavelet coefficients were compared with the pre-exercise coefficients and the post-exercise coefficients in each wavelet level. The characteristics of muscle activity after pedaling exercise were also compared between the elderly subjects and young subjects. For the elderly subjects, the mean wavelet coefficients were significantly decreased in the tibialis anterior and the gastrocnemius medialis at wavelet levels of 3, 4, and 5 (125-62.5, 62.5-31.25, and 31.25-15.625 Hz, respectively), by pedaling exercise. However, the mean power of wavelet levels of 2 and 3 (250-125 and 125-62.5 Hz) within the rectus femoris and the biceps femoris were significantly increased in the young subjects. The effect of pedaling exercise is different from the effects of heavy-resistance training. It was suggested that the muscle coordination, motor unit (MU) firing frequency, and firing fiber type of lower limb muscles are changed with the different characteristics between elderly and young persons by pedaling exercise for 1 month.

Analyses of the possible anti-tumor effect of yokukansan.

The Kampo medicine yokukansan (YKS) has a wide variety of properties such as anxiolytic, anti-inflammatory and analgesic effects, and is also thought to regulate tumor suppression. In this study, we investigated the anti-tumor effect of YKS. We used Lewis lung carcinoma (LLC)-bearing mice that were fed food pellets containing YKS and then performed a fecal microbiota analysis, a microarray analysis for microRNAs (miRNAs) and an in vitro anti-tumor assay. The fecal microbiota analysis revealed that treatment with YKS partly reversed changes in the microbiota composition due to LLC implantation. Furthermore, a miRNA array analysis using blood serum showed that treatment with YKS restored the levels of miR-133a-3p/133b-3p, miR-1a-3p and miR-342-3p following LLC implantation to normal levels. A TargetScan analysis revealed that the epidermal growth factor receptor 1 signaling pathway is one of the major target pathways for these miRNAs. Furthermore, treatment with YKS restored the levels of miR-200b-3p and miR-200c-3p, a recognized mediator of cancer progression and controller of emotion, in the hypothalamus of mice bearing LLC. An in vitro assay revealed that a mixture of pachymic acid, saikosaponins a and d and isoliquiritigenin, which are all contained in YKS, exerted direct and additive anti-tumor effects. The present findings constitute novel evidence that YKS may exert an anti-tumor effect by reversing changes in the fecal microbiota and miRNAs circulating in the blood serum and hypothalamus, and the compounds found in YKS could have direct and additive anti-tumor effects.

Coordination of the upper-limb segments in physiological tremor with various external loads.

BACKGROUND: This study investigates coordination of the upper-limb segments with various external loads by frequency-domain analysis of physiological tremor during the maintenance of limb posture. Physiological tremor is an involuntary oscillation in every segment of a healthy human. MATERIAL/METHODS: A subject raised his right upper limb forward while extending his hand and fingers. Physiological tremor was measured by acceleration sensors attached to four segments: the index finger, hand, forearm, and upper arm. A balloon filled with helium gas was attached to the forearm as a minus-load condition. A weight band was attached as a plus-load condition. The measured signals were evaluated by frequency-domain analysis: power spectrum and coherence spectrum. RESULTS: The amplitude of upper-limb tremor measured from the four segments decreased with the minus-load and increased with the plus-load. However, the degree of the variation depended on the segment. The amplitude of upper-limb tremor measured from the forearm and the hand decreased remarkably with the minus-load, while the amplitude from the upper arm increased with the plus-load. Although adjacent segments were well coordinated, coordination between the segments varied depending on the external load. The minus-load at the forearm led to a lack of coordination between the upper arm and the forearm. To compensate for this, the movements of the forearm and the hand became coordinated. CONCLUSIONS: The experimental protocol of this study allowed implementing a method to estimate the physiological modification of the neuromuscular system under a hypo-gravitational environment.

Comparison of experimental and numerical muscle fiber conduction velocity (MFCV) distribution around the end-plate zone and fiber endings.

BACKGROUND: The distribution of muscle fiber conduction velocity (MFCV) estimated from surface myoelectric signals differs depending on the recording electrode locations. It is assumed in this study that the irregular values of MFCV may be estimated around the end-plate zone and the fiber endings due to effect of unique interference property of myoelectric signals, and its hypothesis is confirmed experimentally and numerically in consideration of the waveform characteristics of surface myoelectric signals. MATERIAL/METHODS: In experimental study, the surface myoelectric signals are recorded by array electrodes during voluntary isometric contraction in biceps brachii muscle. In the numerical study, the surface myoelectric signals in consideration of the interference property of some motor unit activities are calculated from the current dipole model which simulated the firing features of muscle fiber from end-plate zone to fiber endings. MFCV is estimated by the technique of cross-correlation. Maximum correlation coefficient (Rxy(Ts)) and amplitude ratio (AMPratio) are used to evaluate similarity and attenuation rate between traveling signals. RESULTS: In both results of experimental and numerical studies, the MFCV significantly increase when both Rxy (Ts) and AMPratio decrease around the end-plate zone and fiber endings although three parameters denote constant values in the locations other than the end-plate zone and the fiber endings. The high correlativity is recognized between the experimental and numerical data for MFCV, Rxy (Ts), and AMPratio. CONCLUSIONS: Therefore, it is demonstrated by experimental and theoretical studies that MFCV, Rxy(Ts), and AMPratio are influenced by irregular waveform properties depending on both positions of the end-plate and fiber endings.