RNA in Salivary Extracellular Vesicles as a Possible Tool for Systemic Disease Diagnosis

Saliva contains biological information as blood and is recognized as a valuable diagnostic medium for their noninvasiveness. Although "-omics" researches have tried to investigate saliva, the origin and significance of its contents are not clear, and its usage is largely confined to oral disease in the diagnostic and prognostic field. In an attempt to broaden the applicability of saliva and to find systemic disease-derived RNA in saliva, we made mouse models that had human melanoma and isolated extracellular vesicles (EVs) from their saliva by an aqueous 2-phase system (ATPS), then identified and evaluated their expression of human melan-A RNA, which is associated with melanoma on skin. With ATPS, EVs were isolated efficiently and stably while taking less time compared to isolation by ultracentrifugation. When ATPS was used to isolate EVs from saliva, the mean ± SD percentage of EVs recovered from initial EVs was 38.22% ± 18.55% by the number of particles, and the mean ± SD percentage of RNA recovered from the initial amount was 60.33% ± 5.34%. RNAs within isolated EVs were analyzed subsequently by reverse transcription quantitative polymerase chain reaction and polymerase chain reaction from saliva and plasma. In melanoma mice, amplification of human melan-A was identified from saliva and plasma, even though a relative amount of normalized melan-A was lower than that of plasma. These results present a possibility that RNAs derived from systemic disease are transferred into saliva from blood in EVs. Also, they suggest that saliva could be exploited in obtaining information about systemic disease, not only about oral disease, by examining RNAs in EVs from saliva instead of blood.

Advanced Myoelectric Control for Robotic Hand-Assisted Training: Outcome from a Stroke Patient

A hand exoskeleton driven by myoelectric pattern recognition was designed for stroke rehabilitation. It detects and recognizes the user’s motion intent based on electromyography (EMG) signals, and then helps the user to accomplish hand motions in real time. The hand exoskeleton can perform six kinds of motions, including the whole hand closing/opening, tripod pinch/opening, and the “gun” sign/opening. A 52-year-old woman, 8 months after stroke, made 20× 2-h visits over 10 weeks to participate in robot-assisted hand training. Though she was unable to move her fingers on her right hand before the training, EMG activities could be detected on her right forearm. In each visit, she took 4× 10-min robot-assisted training sessions, in which she repeated the aforementioned six motion patterns assisted by our intent-driven hand exoskeleton. After the training, her grip force increased from 1.5 to 2.7 kg, her pinch force increased from 1.5 to 2.5 kg, her score of Box and Block test increased from 3 to 7, her score of Fugl–Meyer (Part C) increased from 0 to 7, and her hand function increased from Stage 1 to Stage 2 in Chedoke–McMaster assessment. The results demonstrate the feasibility of robot-assisted training driven by myoelectric pattern recognition after stroke.

Assessing muscle spasticity with Myotonometric and passive stretch measurements: validity of the Myotonometer

Spasticity of the biceps brachii muscle was assessed using the modified Ashworth Scale (MAS), Myotonometry and repeated passive stretch techniques, respectively. Fourteen subjects with chronic hemiplegia participated in the study. Spasticity was quantified by muscle displacements and compliance from the Myotonometer measurements and resistive torques from the repeated passive stretch at velocities of 5 °/s and 100 °/s, respectively. Paired t-tests indicated a significant decrease of muscle displacement and compliance in the spastic muscles as compared to the contralateral side (muscle displacement: spastic: 4.84 ± 0.33 mm, contralateral: 6.02 ± 0.49 mm, p = 0.038; compliance: spastic: 1.79 ± 0.12 mm/N, contralateral: 2.21 ± 0.18 mm/kg, p = 0.048). In addition, passive stretch tests indicated a significant increase of total torque at the velocity of 100 °/s compared with that of 5 °/s (T_t5 = 2.82 ± 0.41 Nm, T_t100 = 6.28 ± 1.01 Nm, p < 0.001). Correlation analysis revealed significant negative relationships between the stretch test and the Myotonometer measurements (r < −0.5, p < 0.05). Findings of this study provided validation of the Myotonometry technique and its high sensitivity in examination of spasticity in stroke.

Photoplethysmography sampling frequency: pilot assessment of how low can we go to analyze pulse rate variability with reliability?

Pulse rate variability (PRV) analysis appears as the first alternative to heart rate variability analysis for wearable devices; however, there is a constraint on computational load and energy consumption for the limited system resources available to the devices. Considering that adjustment of the sampling frequency is one of the strategies for reducing computational load and power consumption, this study aimed to investigate the influence of sampling frequency (f _s) on PRV analysis and to find the minimum sampling frequency while maintaining reliability. We generated 5000, 2500, 1000, 500, 250, 100, 50, 25, 20, 15, 10, 5 Hz down-sampled photoplethysmograms from 10 kHz-sampled PPGs and derived time- and frequency-domain variables of the PRV. These included AVNN, SDNN, SDSD, RMSSD, NN50, pNN50, total power, VLF, LF, HF, LF/HF, nLF and nHF for each down-sampled signal. Derived variables were compared with heart rate variability of the 10 kHz-sampled electrocardiograms, and then statistically investigated using one-way ANOVA test and Bland-Altman analysis. As a result, significant differences (P  <  0.05) were found for SDNN, SDSD, RMSSD, NN50, pNN50, TP, HF, LF/HF, nLF and nHF, but not for AVNN, VLF and LF. Based on the post hoc tests, it was found that the NN50 and pNN50, SDSD and RMSSD, LF/HF and nHF, SDNN, TP and nLF analysis had significant differences at f _s  ⩽  20 Hz, f _s  ⩽  15 Hz, f _s  ⩽10 Hz; f _s  =  5 Hz, respectively. In other words, a significant difference was not seen for any variable if the f _s was greater than 25 Hz. Consequently, our pilot study suggests that analysis of variability in the time and frequency domain from pulse rate obtained through PPG may be potentially as reliable as that derived from the analysis of the electrocardiogram, provided that f _s  ⩾25 Hz sampling frequency is used.

Assessing the immediate impact of botulinum toxin injection on impedance of spastic muscle

This study aimed to investigate the immediate impacts of Botulinum Toxin A (BoNT-A) injections on the inherent electrical properties of spastic muscles using a newly developed electrical impedance myography (EIM) technique. Impedance measures were performed before and after a BoNT-A injection in biceps brachii muscles of 14 subjects with spasticity. Three major impedance variables, resistance (R), reactance (X) and phase angle (θ) were obtained from three different configurations, and were evaluated using the conventional EIM frequency at 50kHz as well as multiple frequency analysis. Statistical analysis demonstrated a significant decrease of resistance in the injected muscles (Multiple-frequency: R_pre=25.17±1.94Ohm, R_post=23.65±1.63Ohm, p<0.05; 50kHz: R_pre=29.06±2.16Ohm, R_post=27.7±1.89Ohm, p<0.05). Despite this decrease, there were no substantial changes in the reactance, phase angle, or anisotropy features after a BoNT-A injection. The significant changes of muscle resistance were most likely associated with the liquid injection of the BoNT-A-saline solution rather than the immediate toxin effects on the muscle. This study demonstrated high sensitivity of the EIM technique in the detection of alterations to muscle composition.

The Effect of Subcutaneous Fat on Electrical Impedance Myography: Electrode Configuration and Multi-Frequency Analyses

This study investigates the impact of the subcutaneous fat layer (SFL) thickness on localized electrical impedance myography (EIM), as well as the effects of different current electrodes, varying in distance and direction, on EIM output. Twenty-three healthy subjects underwent localized multi-frequency EIM on their biceps brachii muscles with a hand-held electrode array. The EIM measurements were recorded under three different configurations: wide (or outer) longitudinal configuration 6.8 cm, narrow (or inner) longitudinal configuration 4.5 cm, and narrow transverse configuration 4.5 cm. Ultrasound was applied to measure the SFL thickness. Coefficients of determination (R²) of three EIM variables (resistance, reactance, and phase) and SFL thickness were calculated. For the longitudinal configuration, the wide distance could reduce the effects of the subcutaneous fat when compared with the narrow distance, but a significant correlation still remained for all three EIM parameters. However, there was no significant correlation between SFL thickness and reactance in the transverse configuration (R² = 0.0294, p = 0.434). Utilizing a ratio of 50kHz/100kHz phase was found to be able to help reduce the correlation with SFL thickness for all the three configurations. The findings indicate that the appropriate selection of the current electrode distance, direction and the multi-frequency phase ratio can reduce the impact of subcutaneous fat on EIM. These settings should be evaluated for future clinical studies using hand-held localized arrays to perform EIM.

Analysis of Stress Effect on (110)-Oriented Single-Gate SOI nMOSFETs Using a Silicon-Thickness-Dependent Deformation Potential

The stress effect in uniaxially strained (100)- and (110)-oriented single-gate (SG) silicon-on-insulator (SOI) n-type metal-oxide-semiconductor field-effect transistors (MOSFETs) was analyzed. A model of a silicon-thickness-dependent deformation potential (D(as_T(si))) was used for accurate calculation of mobility using a Schrödinger-Poisson solver. The simulation results obtained using the D(ac_T(si)) model exhibited excellent agreement with the measured mobility for both strained and unstrained conditions. The enhancements in electron mobility under conditions of longitudinal tensile strain were analyzed as a function of the silicon thickness and strain. As the silicon thickness decreased, the mobility enhancement in (100) SG MOSFETs reached a peak, whereas it diminished in (110) SG MOSFETs. As the strain increased, mobility enhancement increased in the (110) case, whereas it saturated in the (100) case. Therefore, larger mobility enhancement in the (110) orientation is expected. These differences in enhancement between the (100) and (110) cases resulted from differences in the quantization mass, which affect the energy difference between the 1st subbands of two-fold and four-fold degenerate valleys, as well as occupancy change.

Localized Electrical Impedance Myography of the Biceps Brachii Muscle during Different Levels of Isometric Contraction and Fatigue

This study assessed changes in electrical impedance myography (EIM) at different levels of isometric muscle contraction as well as during exhaustive exercise at 60% maximum voluntary contraction (MVC) until task failure. The EIM was performed on the biceps brachii muscle of 19 healthy subjects. The results showed that there was a significant difference between the muscle resistance (R) measured during the isometric contraction and when the muscle was completely relaxed. Post hoc analysis shows that the resistance increased at higher contractions (both 60% MVC and MVC), however, there were no significant changes in muscle reactance (X) during the isometric contractions. The resistance also changed during different stages of the fatigue task and there were significant decreases from the beginning of the contraction to task failure as well as between task failure and post fatigue rest. Although our results demonstrated an increase in resistance during isometric contraction, the changes were within 10% of the baseline value. These changes might be related to the modest alterations in muscle architecture during a contraction. The decrease in resistance seen with muscle fatigue may be explained by an accumulation of metabolites in the muscle tissue.

Dietary Influence on Calcitropic Hormones and Adiposity in Caucasian and African American Postmenopausal Women Assessed by Structural Equation Modeling (SEM)

OBJECTIVES

To examine differences in hydroxycholecalciferol (25(OH)D) and parathyroid hormone (PTH) concentrations between Caucasian and African American (AA) postmenopausal women, as well as the effects of dietary calcium, protein and vitamin D intakes on 25(OH)D, PTH, and body adiposity using structural equation modeling (SEM).

DESIGN

Population-based prospective cohort study.

SETTING

Academic research using the baseline data from two longitudinal studies. Participants Included n=113 Caucasian and n=40 African American, postmenopausal women who completed the baseline data collection and met inclusion criteria (dietary calcium intake <900 mg/day and being generally healthy) between 2006 and 2010.

MAIN OUTCOME

Dietary intake of calcium and vitamin D, assessed by dietary records, were examined in relation to calcitropic hormones concentrations and adiposity markers. Independent t-tests, confirmatory factor analysis, SEM and multi-group analyses were conducted to examine the aforementioned relationships as well as group differences among hormones, dietary intake, anthropometrics, age and other factors.

RESULTS

Dietary calcium and protein intakes were significantly lower in AA women. Years since menopause were significantly higher in AA compared to Caucasian women. PTH and 25(OH)D levels were significantly lower in AA compared to Caucasian women. Dietary calcium and protein intakes did not influence body adiposity in either group of women. Dietary vitamin D had minimal indirect (via 25(OH)D levels) influence on adiposity.

CONCLUSION

The study confirmed the positive relationship of 25(OH)D with adiposity markers and both AA and Caucasian women. The study provides a unique example of the use of SEM in nutrition research within a clinical context. This model should be further tested in other populations.

3-Iodothyronamine-mediated metabolic suppression increases the phosphorylation of AMPK and induces fuel choice toward lipid mobilization

Despite broad medical application, induction of artificial hypometabolism in vitro and its biochemical consequence have been rarely addressed. This study aimed to elucidate whether 3-iodothyronamine (T1AM) induces hypometabolism in an in vitro model with activation of AMP-activated protein kinase (AMPK) and whether it leads to a switch in primary fuel from carbohydrates to lipids as observed in in vivo models. Mouse C2C12 myotube and T1AM, a natural derivative of thyroid hormone, were used in this study. The oxygen consumption rate (OCR) decreased in a dose-dependent manner in response to 0-100 μM T1AM for up to 10 h. Upon 6-h of exposure to 75 μM T1AM, the OCR was reduced to 60 vs. ~ 95% for the control. The intracellular [AMP]/[ATP] was 1.35-fold higher in T1AM-treated cells. RT-PCR and immunoblotting analyses revealed that treated cells had upregulated p-AMPK/AMPK (1.8-fold), carnitine palmitoyl transferase 1 mRNA, and pyruvate dehydrogenase kinase, and downregulated acetyl CoA carboxylase (0.4-fold) and pyruvate dehydrogenase phosphatase. The treated cells had darker periodic acid-Schiff staining with 1.2-fold greater glycogen content than controls. Taken together, the hypometabolic response of myotubes to T1AM was dramatic and accompanied by increases in both the relative abundance of AMP and AMPK activation, and fuel choice favoring lipids over carbohydrates. These results are consistent with the general trends observed for rodent models and true hibernators.