Correlation of the composite equilibrium score of computerized dynamic posturography and clinical balance tests

AbstractBackgroundThe computerized dynamic posturography has been widely used to access balance control in patients with balance dysfunction. A composite-equilibrium score (CS) can be calculated from the sensory organization test using the computerized dynamic posturography. However, the correlation between the composite equilibrium score and clinical tests and its ability to predict falls has rarely been explored in the past.MethodsA total of 60 patients with chief complaint of dizziness were enrolled in our study, and clinical assessments were done including the sensory organization test (SOT), Timed Up and Go test (TUG), Tinetti Performance-Oriented Mobility Assessment (POMA), and the dynamic gait index (DGI). The age and the subjective feeling of the severity of dizziness quantified by the visual analog scale (VAS) of each patient were also recorded.ResultsStatistical analysis revealed significant correlation between the composite equilibrium score and the TUG, POMA (gait, balance and total scores), and the DGI. However, there is statistically significant correlation between neither the CS and the age nor the VAS of dizziness. When grouping the DGI, POMA (total score), and the TUG cutoff to predict fall risks, the correlations to the CS can still be established except the TUG.ConclusionFrom the results of our study, the validity of the clinical tests was established in assessment of balance function, and clinicians can utilize these tools for preliminary evaluation of patient balance when computerized dynamic posturography is not available. In addition, CS can be used to predict the risk of falls

STAT2 hypomorphic mutant mice display impaired dendritic cell development and antiviral response

Interferons (IFNs) are key regulators for both innate and adaptive immune responses. By screening ENU-mutagenized mice, we identified a pedigree- P117 which displayed impaired response to type I, but not type II, IFNs. Through inheritance test, genetic mapping and sequencing, we found a T to A point mutation in the 5' splice site of STAT2 intron 4–5, leading to cryptic splicing and frame shifting. As a result, the expression of STAT2 protein was greatly diminished in the mutant mice. Nonetheless, a trace amount of functional STAT2 protein was still detectable and was capable of inducing, though to a lesser extent, IFNα-downstream gene expressions, suggesting that P117 is a STAT2 hypomorphic mutant. The restoration of mouse or human STAT2 gene in P117 MEFs rescued the response to IFNα, suggesting that the mutation in STAT2 is most likely the cause of the phenotypes seen in the pedigree. Development of different subsets of lymphocytes appeared to be normal in the mutant mice except that the percentage and basal expression of CD86 in splenic pDC and cDC were reduced. In addition, in vitro Flt3L-dependent DC development and TLR ligand-mediated DC differentiation were also defective in mutant cells. These results suggest that STAT2 positively regulates DC development and differentiation. Interestingly, a severe impairment of antiviral state and increased susceptibility to EMCV infection were observed in the mutant MEFs and mice, respectively, suggesting that the remaining STAT2 is not sufficient to confer antiviral response. In sum, the new allele of STAT2 mutant reported here reveals a role of STAT2 for DC development and a threshold requirement for full functions of type I IFNs

Effects of Noise Electrical Stimulation on Proprioception, Force Control, and Corticomuscular Functional Connectivity

Sensory afferent inputs play an important role in neuromuscular functions. Subsensory level noise electrical stimulation enhances the sensitivity of peripheral sensory system and improves lower extremity motor function. The current study aimed to investigate the immediate effects of noise electrical stimulation on proprioceptive senses and grip force control, and whether there are associated neural activities in the central nervous system. Fourteen healthy adults participated in 2 experiments on 2 different days. In day 1, participants performed grip force and joint proprioceptive tasks with and without (sham) noise electrical stimulation. In day 2, participants performed grip force steady hold task before and after 30-min noise electrical stimulation. Noise stimulation was applied with surface electrodes secured along the course of the median nerve and proximal to the coronoid fossa EEG power spectrum density of bilateral sensorimotor cortex and coherence between EEG and finger flexor EMG were calculated and compared. Wilcoxon Signed-Rank Tests were used to compare the differences of proprioception, force control, EEG power spectrum density and EEG-EMG coherence between noise electrical stimulation and sham conditions. The significance level (alpha) was set at 0.05. Our study found that noise stimulation with optimal intensity could improve both force and joint proprioceptive senses. Furthermore, individuals with higher gamma coherence showed better force proprioceptive sense improvement with 30-min noise electrical stimulation. These observations indicate the potential clinical benefits of noise stimulation on individuals with impaired proprioceptive senses and the characteristics of individuals who might benefit from noise stimulation

Oral Rg1 supplementation strengthens antioxidant defense system against exercise-induced oxidative stress in rat skeletal muscles

BACKGROUND: Previous studies reported divergent results on nutraceutical actions and free radical scavenging capability of ginseng extracts. Variations in ginsenoside profile of ginseng due to different soil and cultivating season may contribute to the inconsistency. To circumvent this drawback, we assessed the effect of major ginsenoside-Rg1 (Rg1) on skeletal muscle antioxidant defense system against exhaustive exercise-induced oxidative stress. METHODS: Forty weight-matched rats were evenly divided into control (N = 20) and Rg1 (N = 20) groups. Rg1 was orally administered at the dose of 0.1 mg/kg bodyweight per day for 10-week. After this long-term Rg1 administration, ten rats from each group performed an exhaustive swimming, and remaining rats considered as non-exercise control. Tibialis anterior (TA) muscles were surgically collected immediately after exercise along with non-exercise rats. RESULTS: Exhaustive exercise significantly (p<0.05) increased the lipid peroxidation of control group, as evidenced by elevated malondialdehyde (MDA) levels. The increased oxidative stress after exercise was also confirmed by decreased reduced glutathione to oxidized glutathione ratio (GSH/GSSG ratio) in control rats. However, these changes were completely eliminated in Rg1 group. Catalase (CAT) and glutathione peroxidase (GPx) activities were significantly (p<0.05) increased by Rg1 in non-exercise rats, while no significant change after exercise. Nevertheless, glutathione reductase (GR) and glutathione S-transferase (GST) activities were significantly increased after exercise in Rg1 group. CONCLUSIONS: This study provide compelling evidences that Rg1 supplementation can strengthen antioxidant defense system in skeletal muscle and completely attenuate the membrane lipid peroxidation induced by exhaustive exercise. Our findings suggest that Rg1 can use as a nutraceutical supplement to buffer the exhaustive exercise-induced oxidative stress

SirT1—A Sensor for Monitoring Self-Renewal and Aging Process in Retinal Stem Cells

Retinal stem cells bear potency of proliferation, self-renewal, and differentiation into many retinal cells. Utilizing appropriate sensors one can effectively detect the self-renewal and aging process abilities. Silencing information regulator (SirT1), a member of the sirtuin family, is a NAD-dependent histone deacetylase and an essential mediator for longevity in normal cells by calorie restriction. We firstly investigate the SirT1 mRNA expression in retinal stem cells from rats and 19 human eyes of different ages. Results revealed that SirT1 expression was significantly decreased in in vivo aged eyes, associated with poor self-renewal abilities. Additionally, SirT1 mRNA levels were dose-dependently increased in resveratrol- treated retinal stem cells. The expression of SirT1 on oxidative stress-induced damage was significantly decreased, negatively correlated with the level of intracellular reactive oxygen species production. Treatment with resveratrol could effectively further reduce oxidative stress induced by H2O2 treatment in retinal stem cells. Importantly, the anti-oxidant effects of resveratrol in H2O2-treated retinal stem cells were significantly abolished by knockdown of SirT1 expression (sh-SirT1). SirT1 expression provides a feasible sensor in assessing self-renewal and aging process in retinal stem cells. Resveratrol can prevent reactive oxygen species-induced damages via increased retinal SirT1 expression

Stem Cell-Based Neuroprotective and Neurorestorative Strategies

Stem cells, a special subset of cells derived from embryo or adult tissues, are known to present the characteristics of self-renewal, multiple lineages of differentiation, high plastic capability, and long-term maintenance. Recent reports have further suggested that neural stem cells (NSCs) derived from the adult hippocampal and subventricular regions possess the utilizing potential to develop the transplantation strategies and to screen the candidate agents for neurogenesis, neuroprotection, and neuroplasticity in neurodegenerative diseases. In this article, we review the roles of NSCs and other stem cells in neuroprotective and neurorestorative therapies for neurological and psychiatric diseases. We show the evidences that NSCs play the key roles involved in the pathogenesis of several neurodegenerative disorders, including depression, stroke and Parkinson’s disease. Moreover, the potential and possible utilities of induced pluripotent stem cells (iPS), reprogramming from adult fibroblasts with ectopic expression of four embryonic genes, are also reviewed and further discussed. An understanding of the biophysiology of stem cells could help us elucidate the pathogenicity and develop new treatments for neurodegenerative disorders. In contrast to cell transplantation therapies, the application of stem cells can further provide a platform for drug discovery and small molecular testing, including Chinese herbal medicines. In addition, the high-throughput stem cell-based systems can be used to elucidate the mechanisms of neuroprotective candidates in translation medical research for neurodegenerative diseases

Efficacy of a Computerized Sensor System for Evaluation and Training of Dizzy Patients

Patients with vestibular hypofunction often experience dizziness and unsteadiness while moving their heads. Appropriate sensors can effectively detect a patient’s dynamic visual acuity and associated body balance control. Forty-one vestibular-deficit patients and 10 normal individuals were invited to participate in this study. Questionnaires, clinical assessment scales and objective measures were evaluated on participants’ first visits. After 12 sessions of training, all scales were evaluated again on vestibular-deficit patients. The computerized system was composed of sensors, including a gyro and strain gauges, data acquisition accessories and LabVIEW software. Results revealed that the system could effectively distinguish normal subjects from subjects with vestibular deficits. In addition, after a rehabilitation program, subjects’ subjective and objective performances were significantly improved. Based on our results, we concluded that the present system, which uses a gyro and strain gauges, may provide an effective method for assessing and treating vestibular-deficit patients

On Holo-Hilbert spectral analysis: a full informational spectral representation for nonlinear and non-stationary data

The Holo-Hilbert spectral analysis (HHSA) method is introduced to cure the deficiencies of traditional spectral analysis and to give a full informational representation of nonlinear and non-stationary data. It uses a nested empirical mode decomposition and Hilbert–Huang transform (HHT) approach to identify intrinsic amplitude and frequency modulations often present in nonlinear systems. Comparisons are first made with traditional spectrum analysis, which usually achieved its results through convolutional integral transforms based on additive expansions of an a priori determined basis, mostly under linear and stationary assumptions. Thus, for non-stationary processes, the best one could do historically was to use the time–frequency representations, in which the amplitude (or energy density) variation is still represented in terms of time. For nonlinear processes, the data can have both amplitude and frequency modulations (intra-mode and inter-mode) generated by two different mechanisms: linear additive or nonlinear multiplicative processes. As all existing spectral analysis methods are based on additive expansions, either a priori or adaptive, none of them could possibly represent the multiplicative processes. While the earlier adaptive HHT spectral analysis approach could accommodate the intra-wave nonlinearity quite remarkably, it remained that any inter-wave nonlinear multiplicative mechanisms that include cross-scale coupling and phase-lock modulations were left untreated. To resolve the multiplicative processes issue, additional dimensions in the spectrum result are needed to account for the variations in both the amplitude and frequency modulations simultaneously. HHSA accommodates all the processes: additive and multiplicative, intra-mode and inter-mode, stationary and non-stationary, linear and nonlinear interactions. The Holo prefix in HHSA denotes a multiple dimensional representation with both additive and multiplicative capabilities