The Influence of Breathing Exercises on Regional Ventilation in Healthy and Patients with Chronic Obstructive Pulmonary Disease.

We hypothesized that the respiratory exercises have uniform effects on ventilation in healthy subjects but the effects varied in patients with chronic obstructive pulmonary disease (COPD). In this study, a total of 30 healthy volunteers and 9 patients with COPD were included. Data were recorded continuously during (1) diaphragmatic breathing; (2) pursed lip breathing with full inhalation; (3) pursed lip combining diaphragmatic breathing. The sequence of the three breathing exercises was randomized using machine generated random permutation. Spatial and temporal ventilation distributions were evaluated with electrical impedance tomography. Results showed that, tidal volume was significantly larger during various breathing exercises compared to quiet tidal breathing, in both healthy and COPD (p < 0.01). However, for other EIT-based parameters, statistical significances were only observed in healthy volunteers, not in patients. Diaphragmatic breathing alone might not be able to decrease functional residual capacity in COPD and the effect varied largely from patient to patient (6:3, decrease vs. increase). Ventilation distribution moved toward ventral regions in healthy during breathing exercises (p < 0.0001). Although this trend was observed in the COPD, the differences were not significant. Ventilation became more homogeneous when diaphragmatic breathing technique was implemented (p < 0.0001). Again, the improvements were not significant in COPD. Regional ventilation delay was relatively high in COPD and comparable in various breathing periods. In conclusions, the impact of pursed lip and diaphragmatic breathing varied in different patients with COPD. Breathing exercise may need to be individualized to maximize the training efficacy with help of EIT.

Circulating Exosomes from Mice with LPS-Induced Bone Loss Inhibit Osteoblast Differentiation.

Osteoimmunology focuses on the intermodulation between bone and the immune system. Lipopolysaccharide (LPS)-induced bone loss models are commonly used to investigate the interface between inflammation and osteoporosis. Circulating exosomes can regulate physiological and pathological processes through exosomal microRNAs and proteins. In this study, we observed reduced osteoblast number and bone formation in LPS-induced bone loss mice (LPS mice). Levels of circulating exosomes were increased by ~ twofold in LPS mice, and the expression of exosomal miRNAs was significantly changed. miRNAs (miRNA-125b-5p, miRNA-132-3p, and miRNA-214-3p) that were reported to inhibit osteoblast activity were significantly increased in the serum exosomes and bone tissues of LPS mice. Additionally, LPS-induced increases in exosomes significantly inhibited the osteogenic differentiation of MC3T3-E1 cells.

The small protein MafG plays a critical role in MC3T3-E1 cell apoptosis induced by simulated microgravity and radiation.

Microgravity and radiation exposure-induced bone damage is one of the most significant alterations in astronauts after long-term spaceflight. However, the underlying mechanism is still largely unknown. Recent ground-based simulation studies have suggested that this impairment is likely mediated by increased production of reactive oxygen species (ROS) during spaceflight. The small Maf protein MafG is a basic-region leucine zipper-type transcription factor, and it globally contributes to regulation of antioxidant and metabolic networks. Our research investigated the role of MafG in the process of apoptosis induced by simulated microgravity and radiation in MC3T3-E1 cells. We found that simulated microgravity or radiation alone decreased MafG expression and elevated apoptosis in MC3T3-E1 cells, and combined simulated microgravity and radiation treatment aggravated apoptosis. Meanwhile, under normal conditions, increased ROS levels facilitated apoptosis and downregulated the expression of MafG in MC3T3-E1 cells. Overexpression of MafG decreased apoptosis induced by simulated microgravity and radiation. These findings provide new insight into the mechanism of bone damage induced by microgravity and radiation during space flight.

HDAC6 Negatively Regulates miR-155-5p Expression to Elicit Proliferation by Targeting RHEB in Microvascular Endothelial Cells under Mechanical Unloading.

Mechanical unloading contributes to significant cardiovascular deconditioning. Endothelial dysfunction in the sites of microcirculation may be one of the causes of the cardiovascular degeneration induced by unloading, but the detailed mechanism is still unclear. Here, we first demonstrated that mechanical unloading inhibited brain microvascular endothelial cell proliferation and downregulated histone deacetylase 6 (HDAC6) expression. Furthermore, HDAC6 promoted microvascular endothelial cell proliferation and attenuated the inhibition of proliferation caused by clinorotation unloading. To comprehensively identify microRNAs (miRNAs) that are regulated by HDAC6, we analyzed differential miRNA expression in microvascular endothelial cells after transfection with HDAC6 siRNA and selected miR-155-5p, which was the miRNA with the most significantly increased expression. The ectopic expression of miR-155-5p inhibited microvascular endothelial cell proliferation and directly downregulated Ras homolog enriched in brain (RHEB) expression. Moreover, RHEB expression was downregulated under mechanical unloading and was essential for the miR-155-5p-mediated promotion of microvascular endothelial cell proliferation. Taken together, these results are the first to elucidate the role of HDAC6 in unloading-induced cell growth inhibition through the miR-155-5p/RHEB axis, suggesting that the HDAC6/miR-155-5p/RHEB pathway is a specific target for the preventative treatment of cardiovascular deconditioning.

MiR-30 family members inhibit osteoblast differentiation by suppressing Runx2 under unloading conditions in MC3T3-E1 cells.

Disuse osteoporosis is common in prolonged therapeutic bed rest, space flight and immobilization due to limb fracture, which is related to reduction of mechanical stress on bone. Mechanical unloading can inhibit the differentiation of osteoblasts, but the detailed mechanism is still unclear. Runt-related transcription factor-2 (Runx2), is an important transcription factor, which plays a crucial role in disuse osteoporosis induced by unloading conditions. In this study, we found that Runx2-targeting mechano-sensitive miR-30 family members, miR-30b, miR-30c, miR-30d and miR-30e increased significantly, and were negatively correlated with the expression of Runx2 under unloading condition. Further studies found that the four miRNAs inhibited the expression of Runx2 and osteoblast differentiation under normal loading, and the knockdown of these miRNAs attenuated partly the inhibition of osteoblast differentiation induced by unloading condition in MC3T3-E1 cells. This study is the first to report miR-30 family members can regulate partly the dysfunction of osteoblasts under unloading condition, which is expected to be targets for the treatment of disuse osteoporosis.

miR-181c-5p mediates simulated microgravity-induced impaired osteoblast proliferation by promoting cell cycle arrested in the G2 phase.

Impaired osteoblast proliferation plays fundamental roles in microgravity-induced bone loss, and cell cycle imbalance may result in abnormal osteoblast proliferation. However, whether microgravity exerts an influence on the cell cycle in osteoblasts or what mechanisms may underlie such an effect remains to be fully elucidated. Herein, we confirmed that simulated microgravity inhibits osteoblast proliferation. Then, we investigated the effect of mechanical unloading on the osteoblast cell cycle and found that simulated microgravity arrested the osteoblast cell cycle in the G2 phase. In addition, our data showed that cell cycle arrest in osteoblasts from simulated microgravity was mainly because of decreased cyclin B1 expression. Furthermore, miR-181c-5p directly inhibited cyclin B1 protein translation by binding to a target site in the 3'UTR. Lastly, we demonstrated that inhibition of miR-181c-5p partially counteracted cell cycle arrest and decreased the osteoblast proliferation induced by simulated microgravity. In conclusion, our study demonstrates that simulated microgravity inhibits cell proliferation and induces cell cycle arrest in the G2 phase in primary mouse osteoblasts partially through the miR-181c-5p/cyclin B1 pathway. This work may provide a novel mechanism of microgravity-induced detrimental effects on osteoblasts and offer a new avenue to further investigate bone loss induced by mechanical unloading.

Simulated microgravity reduces intracellular-free calcium concentration by inhibiting calcium channels in primary mouse osteoblasts.

Calcium homeostasis in osteoblasts plays fundamental roles in the physiology and pathology of bone tissue. Various types of mechanical stimuli promote osteogenesis and increase bone formation elicit increases in intracellular-free calcium concentration in osteoblasts. However, whether microgravity, a condition of mechanical unloading, exerts an influence on intracellular-free calcium concentration in osteoblasts or what mechanisms may underlie such an effect are unclear. Herein, we show that simulated microgravity reduces intracellular-free calcium concentration in primary mouse osteoblasts. In addition, simulated microgravity substantially suppresses the activities of L-type voltage-sensitive calcium channels, which selectively allow calcium to cross the plasma membrane from the extracellular space. Moreover, the functional expression of ryanodine receptors and inositol 1,4,5-trisphosphate receptors, which mediate the release of calcium from intracellular storage, decreased under simulated microgravity conditions. These results suggest that simulated microgravity substantially reduces intracellular-free calcium concentration through inhibition of calcium channels in primary mouse osteoblasts. Our study may provide a novel mechanism for microgravity-induced detrimental effects in osteoblasts, offering a new avenue to further investigate bone loss induced by mechanical unloading.

Simulated Microgravity Promotes Angiogenesis through RhoA-Dependent Rearrangement of the Actin Cytoskeleton.

BACKGROUND/AIMS: Microgravity leads to hydrodynamic alterations in the cardiovascular system and is associated with increased angiogenesis, an important aspect of endothelial cell behavior to initiate new vessel growth. Given the critical role of Rho GTPase-dependent cytoskeleton rearrangement in cell migration, small GTPase RhoA might play a potential role in microgravity-induced angiogenesis. METHODS: We examined the organization of actin filaments by FITC-conjugated phalloidin staining, as well as the expression and activity of RhoA by quantitative PCR and Western blot, in human umbilical vein endothelial cells (HUVECs) under normal gravity and simulated microgravity. Effect of simulated microgravity on the wound closure and tube formation in HUVECs, and their dependence on RhoA, were also analyzed by cell migration and tube formation assays. RESULTS: We show that in HUVECs actin filaments are disorganized and RhoA activity is reduced by simulated microgravity. Blocking RhoA activity either by C3 transferase Rho inhibitor or siRNA knockdown mimicked the effect of simulated microgravity on inducing actin filament disassembly, followed by enhanced wound closure and tube formation in HUVECs, which closely resembled effects seen on microgravity-treated cells. In contrast, overexpressing RhoA in microgravity-treated HUVECs restored the actin filaments, and decreased wound closure and tube formation abilities. CONCLUSION: These results suggest that RhoA inactivation is involved in the actin rearrangement-associated angiogenic responses in HUVECs during simulated microgravity.

Effect of a 21-day balneotherapy program on blood cell counts, ponogen levels, and blood biochemical indexes in servicemen in sub-health condition.

[Purpose] The aim of our study was to explore the changes in the blood of servicemen in sub-health conditions during a 21-day balneotherapy program. [Subjects and Methods] For this study, 129 servicemen in sub-health condition were recruited. The subjects were randomly divided into either the balneotherapy group (70) or the control group (59). Subjects in the balneotherapy group received whole-body immersion bath therapy in thermomineral water (30 min daily) for 21 days. Their blood samples were examined 1 day before and after balneotherapy. The parameters studied included mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), white blood cell (WBC), lactic acid (LAC), alanine aminotransferase (ALT), glucose (GLU), and triglycerides (TG) levels. [Results] After 21 days of balneotherapy, MCH levels and MCHC increased significantly and WBC counts increased significantly. LAC levels decreased significantly. ALT, GLU, and TG levels decreased significantly. In the control group, there were no statistical differences before and after tap water baths following the same procedure. [Conclusion] A 21-day balneotherapy program significantly improved blood cell counts and blood biochemical indexes and reduced ponogen levels in servicemen in sub-health condition.

The Impact of Simulated Weightlessness on Endothelium-Dependent Angiogenesis and the Role of Caveolae/Caveolin-1.

BACKGROUND/AIMS: The potential role of caveolin-1 in modulating angiogenesis in microgravity environment is unexplored. METHODS: Using simulated microgravity by clinostat, we measured the expressions and interactions of caveolin-1 and eNOS in human umbilical vein endothelial cells. RESULTS: We found that decreased caveolin-1 expression is associated with increased expression and phosphorylation levels of eNOS in endothelial cells stimulated by microgravity, which causes a dissociation of eNOS from caveolin-1 complexes. As a result, microgravity induces cell migration and tube formation in endothelial cell in vitro that depends on the regulations of caveolin-1. CONCLUSION: Our study provides insight for the important endothelial functions in altered gravitational environments.

Monitoring of spontaneous pneumothorax using electrical impedance tomography: A case report.

Pneumothorax is an emergency in thoracic surgeries and respiratory medicine. A technique is warranted for real-time monitoring of pneumothorax at the bedside so that rapid diagnosis and timely intervention can be achieved. We report herein a case in which electrical impedance tomography (EIT) was employed at the bedside to monitor lung ventilation of a patient with spontaneous pneumothorax during treatment. It was found that the affected side/healthy side ventilation ratio and global inhomogeneity were strongly correlated with the severity of pneumothorax. The use of EIT allowed intuitive observation of the effect of pneumothorax on ventilation, which helped the doctors make immediate diagnosis and intervention. After timely and successful treatment, the patient was discharged. This is the first case reporting a complete therapeutic course of spontaneous pneumothorax assessed with EIT. Our case demonstrated that EIT could monitor regional ventilation loss of the affected side of pneumothorax patients at the bedside, and dynamically assess the treatment effect of pneumothorax, which provides an important imaging basis for clinical pneumothorax treatment.

Evaluation of adjacent and opposite current injection patterns for a wearable chest electrical impedance tomography system.

Objective.Wearable electrical impedance tomography (EIT) can be used to monitor regional lung ventilation and perfusion at the bedside. Due to its special system architecture, the amplitude of the injected current is usually limited compared to stationary EIT system. This study aims to evaluate the performance of current injection patterns with various low-amplitude currents in healthy volunteers.Approach.A total of 96 test sets of EIT measurement was recorded in 12 healthy subjects by employing adjacent and opposite current injection patterns with four amplitudes of small current (i.e. 1 mA, 500 uA, 250 uA and 125 uA). The performance of the two injection patterns with various currents was evaluated in terms of signal-to-noise ratio (SNR) of thorax impedance, EIT image metrics and EIT-based clinical parameters.Main results.Compared with adjacent injection, opposite injection had higher SNR (p< 0.01), less inverse artifacts (p< 0.01), and less boundary artifacts (p< 0.01) with the same current amplitude. In addition, opposite injection exhibited more stable EIT-based clinical parameters (p< 0.01) across the current range. For adjacent injection, significant differences were found for three EIT image metrics (p< 0.05) and four EIT-based clinical parameters (p< 0.01) between the group of 125 uA and the other groups.Significance.For better performance of wearable pulmonary EIT, currents greater than 250 uA should be used in opposite injection, 500 uA in adjacent one, to ensure a high level of SNR, a high quality of reconstructed image as well as a high reliability of clinical parameters.

Visualizing pursed lips breathing of patients with chronic obstructive pulmonary disease through evaluation of global and regional ventilation using electrical impedance tomography.

Objective. This study aims to explore the possibility of using electrical impedance tomography (EIT) to assess pursed lips breathing (PLB) performance of patients with chronic obstructive pulmonary disease (COPD).Methods. 32 patients with COPD were assigned equally to either the conventional group or the EIT guided group. All patients were taught to perform PLB by a physiotherapist without EIT in the conventional group or with EIT in the EIT guided group for 10 min. The ventilation of all patients in the final test were continuously monitored using EIT and the PLB performances were rated by another physiotherapist before and after reviewing EIT. The global and regional ventilation between two groups as well as between quite breathing (QB) and PLB were compared and rating scores with and without EIT were also compared.Results.For global ventilation, the inspiratory depth and the ratio of expiratory-to-inspiratory time during PLB was significantly larger than those during QB for both group (P< 0.001). The inspiratory depth and the ratio of expiratory-to-inspiratory time during PLB in the EIT guided group were higher compared to those in the conventional group (P< 0.001), as well as expiratory flow expiratory uniformity and respiratory stability were better (P< 0.001). For regional ventilation, center of ventilation significantly decreased during PLB (P< 0.05). The expiratory time constant during PLB in the EIT guided group was greater than that in the conventional group (P< 0.001). Additionally, Bland-Altman plots analysis suggested a high concordance between subjective rating and rating with the help of EIT, but the score rated after EIT observation significantly lower than that rated subjectively in both groups (score drop of -2.68 ± 1.1 in the conventional group and -1.19 ± 0.72 in the EIT guided group,P< 0.01).Conclusion.EIT could capture the details of PLB maneuver, which might be a potential tool to quantitatively evaluate PLB performance and thus assist physiotherapists to teach PLB maneuver to patients.

Electrical impedance tomography as a bedside assessment tool for COPD treatment during hospitalization.

For patients with chronic obstructive pulmonary disease (COPD), the assessment of the treatment efficacy during hospitalization is of importance to the optimization of clinical treatments. Conventional spirometry might not be sensitive enough to capture the regional lung function development. The study aimed to evaluate the feasibility of using electrical impedance tomography (EIT) as an objective bedside evaluation tool for the treatment of acute exacerbation of COPD (AECOPD). Consecutive patients who required hospitalization due to AECOPD were included prospectively. EIT measurements were conducted at the time of admission and before the discharge simultaneously when a forced vital capacity maneuver was conducted. EIT-based heterogeneity measures of regional lung function were calculated based on the impedance changes over time. Surveys for attending doctors and patients were designed to evaluate the ease of use, feasibility, and overall satisfaction level to understand the acceptability of EIT measurements. Patient-reported outcome assessments were conducted. User's acceptance of EIT technology was investigated with a five-dimension survey. A total of 32 patients were included, and 8 patients were excluded due to the FVC maneuver not meeting the ATS criteria. Spirometry-based lung function was improved during hospitalization but not significantly different (FEV1 %pred.: 35.8% ± 6.7% vs. 45.3% ± 8.8% at admission vs. discharge; p = 0.11. FVC %pred.: 67.8% ± 0.4% vs. 82.6% ± 5.0%; p = 0.15. FEV1/FVC: 0.41 ± 0.09 vs. 0.42 ± 0.07, p = 0.71). The symptoms of COPD were significantly improved, but the correlations between the improvement of symptoms and spirometry FEV1 and FEV1/FVC were low (R = 0.1 and -0.01, respectively). The differences in blood gasses and blood tests were insignificant. All but one EIT-based regional lung function parameter were significantly improved after hospitalization. The results highly correlated with the patient-reported outcome assessment (R > 0.6, p < 0.001). The overall acceptability score of EIT measurement for both attending physicians and patients was high (4.1 ± 0.8 for physicians, 4.5 ± 0.5 for patients out of 5). These results demonstrated that it was feasible and acceptable to use EIT as an objective bedside evaluation tool for COPD treatment efficacy.

Clinorotation enhances autophagy in vascular endothelial cells.

Individuals exposed to extended periods of spaceflight or prolonged 6° head-down-tilt bed rest often suffer from health hazards represented by cardiovascular deconditioning. Many studies have reported that alterations in vascular endothelial cells contribute to cardiovascular dysfunction induced by microgravity. Autophagy, a lysosomal degradation pathway, serves an adaptive role for survival, differentiation, and development in cellular homeostasis, and can be triggered by various environmental stimuli. However, whether autophagy can be induced in endothelial cells by real or simulated microgravity remains to be determined. This study was designed to investigate the effects of simulated microgravity on the activation of autophagy in human umbilical vein endothelial cells (HUVECs). We report here that clinorotation, a simulated model of microgravity, enhances autophagosome formation, increases LC3 and beclin-1 expression, and promotes the conversion of LC3-I to LC3-II in HUVECs. These results demonstrate that simulated microgravity for 48 h activates autophagy of vascular endothelial cells.

Discrimination between human normal renal tissue and renal cell carcinoma by dielectric properties using in-vitro BIA.

Renal cell carcinoma (RCC) poses a serious threat to human health, which urgently requires a method that can quickly distinguish between human normal renal tissue (NRT) and RCC for the purpose of accurate detection in clinical practice. The significant difference in cell morphology between NRT and RCC tissue underlies the great potential of the bioelectrical impedance analysis (BIA) to distinguish two types of human tissues. The study aims to achieve such discrimination through comparison of their dielectric properties within the frequency range from 10 Hz to 100 MHz. The dielectric properties of 69 cases of human normal and cancer renal tissue were measured 15 min after tissue isolation in a strictly controlled environment (37°C, 90% humidity). In addition to the impedance parameters (resistivity, conductivity and relative permittivity), the characteristic parameters extracted from the Cole curve were also compared between NRT and RCC. Furthermore, a novel index, distinguishing coefficient (DC), was used to obtain the optimal frequency for discrimination between NRT and RCC. In terms of impedance parameters, the RCC conductivity at low frequencies (<1 kHz) was about 1.4 times as large as that of NRT, and its relative permittivity was also significantly higher (p < 0.05). In terms of characteristic parameters, two characteristic frequencies (14.1 ± 1.1 kHz and 1.16 ± 0.13 MHz) were found for NRT while only one for RCC (0.60 ± 0.05 MHz). A significant difference of low-frequency resistance (R0) between RCC and NRT was also observed (p < 0.05). As for the new index DC, relative permittivity DCs below 100 Hz and at around 14 kHz were both greater than 1. These findings further confirm the feasibility of discrimination between RCC and NRT and also provide data in favor of further clinical study of BIA to detect the surgical margins.

The influence of gravity on electrical impedance tomography measurements during upper body position change.

Objective: The aim of the study was to examine the influence of gravity on regional ventilation measured by electrical impedance tomography (EIT) with the standard electrode belt position at the 5th intercostal space during tilting from supine to sitting positions. Methods: A total of 30 healthy volunteers were examined prospectively in supine position during quiet tidal breathing. Subsequently, the bed was tilted so that the upper body of the subjects achieved 30, 60 and 90° every 3 min. Regional ventilation distribution and end-expiratory lung impedance (EELI) were monitored with EIT throughout the whole experiment. Absolute tidal volumes were measured with spirometry and the volume-impedance ratio was calculated for each position. Results: The volume-impedance ratio did not differ statistically between the studied body positions but 11 subjects exhibited a large change in ratio at one of the positions (outside 99.3% coverage). In general, ventilation distribution became more heterogeneous and moved towards dorsal regions as the upper body was tilted to 90-degree position. EELI increased and tidal volume decreased. The lung regions identified at various positions differed significantly. Conclusion: Gravity has non-negligible influence on EIT data, as the upper body tilted from supine to sitting positions. The standard electrode belt position might be reconsidered if ventilation distribution is to be compared between supine and sitting positions.

Synergistic effects of transcutaneous vagus nerve stimulation and inhibitory control training on electrophysiological performance in healthy adults.

Transcutaneous vagal nerve stimulation (tVNS) is a non-invasive nerve stimulation technique that exerts a positive "exogenous" online neuromodulatory effect on inhibitory control (IC). Additionally, IC training (ICT) is an effective approach for enhancing IC via the "endogenous" activation of brain regions implicated in this process. The aim of the present study was to examine the synergistic effects of tVNS and ICT on IC enhancement. For this, we measured the changes in neural activity in frontal, fronto-central, and central regions in the time domain of the N2 component and the frequency domain of alpha power during the stop signal task. A total of 58 participants were randomly divided into four groups that received five sessions of either ICT or sham ICT with either online tVNS or sham tVNS. No differences in N2 amplitude were detected after any of the interventions. However, N2 latency shortened after tVNS + ICT in frontal, fronto-central, and central regions. N2 latency shortened after the intervention of sham tVNS + ICT in frontal region. Moreover, alpha power after tVNS + ICT intervention was larger than those of the other interventions in frontal, fronto-central, and central regions. The obtained electrophysiological data suggested that combining tVNS with ICT has synergistic ameliorative effects on IC, and provide evidence supporting the IC-enhancing potential of tVNS combined with ICT.

Histone methyltransferase Setdb1 mediates osteogenic differentiation by suppressing the expression of miR-212-3p under mechanical unloading.

Emerging evidence indicates that multiple mechanisms are involved in bone loss induced by mechanical unloading. Thus far, few study has established the pathophysiological role of histone modification for osteogenic differentiation under mechanical unloading. Here we demonstrated that the histone H3 lysine 9 (H3K9) methyltransferase Setdb1, which was sensitive to mechanical unloading, was increased during osteogenic differentiation of MC3T3-E1 cells for the first time. Knockdown of Setdb1 significantly blocked osteoblast function in vivo and in vitro. Through bioinformatics analysis of candidate miRNAs regulated by H3K9me3, we further identified that Setdb1 inhibited the expression of miR-212-3p by regulating the formation of H3K9me3 in the promoter region. Mechanically, we revealed that miR-212-3p was upregulated under mechanical unloading and suppressed osteogenic differentiation by directly downregulating High mobility group box 1 protein (Hmgb1) expression. Furthermore, we verified the molecular mechanism of the SETDB1/miR-212-3p/HMGB1 pathway in hFOB cells under mechanical unloading. In summary, these data demonstrate the essential function of the Setdb1/miR-212-3p/Hmgb1 pathway in osteogenic differentiation under mechanical unloading, and present a potential protective strategies against bone loss induced by mechanical unloading.

Visual symptoms and G-induced loss of consciousness in 594 Chinese Air Force aircrew--a questionnaire survey.

A questionnaire survey was performed for the first time to assess the prevalence of visual symptoms and G-induced loss of consciousness (G-LOC) due to +Gz exposure in the Chinese Air Force (CAF) to determine the effectiveness of current G tolerance training. Responses were received from 594 individuals. Among them, 302 reported at least one episode of some sort of symptoms related to +Gz, including 110 (18.5%) with visual blurring, 231 (38.9%) with greyout, 111 (18.7%) with blackout, and 49 (8.2%) with G-LOC. Incidences were most common in aircrew with 250-1,000 flying hours (53.6%) and were more prevalent in those with fewer on type flying hours (p < 0.001). The most common situation was reported between +5 and 5.9 Gz. The results indicate a fairly high prevalence of visual symptoms and G-LOC among Chinese Air Force aircrew. There remains considerable scope for +Gz education, particularly in the early centrifuge training and selection of rational physical exercises.