Bed Rest Conditions Research Articles

Mitochondrial bioenergetics are not associated with myofibrillar protein synthesis rates.

Mitochondria represent key organelles influencing cellular homeostasis and have been implicated in the signalling events regulating protein synthesis. We examined whether mitochondrial bioenergetics (oxidative phosphorylation and reactive oxygen species (H2O2) emission, ROS) measured in vitro in permeabilized muscle fibres represent regulatory factors for integrated daily muscle protein synthesis rates and skeletal muscle mass changes across the spectrum of physical activity, including free-living and bed-rest conditions: n=19 healthy, young men (26±4years, 23.4±3.3kg/m2) and following 12weeks of resistance-type exercise training: n=10 healthy older men (70±3years, 25.2±2.1kg/m2). Additionally, we evaluated the direct relationship between attenuated mitochondrial ROS emission and integrated daily myofibrillar and sarcoplasmic protein synthesis rates in genetically modified mice (mitochondrial-targeted catalase, MCAT). Neither oxidative phosphorylation nor H2O2 emission were associated with muscle protein synthesis rates in healthy young men under free-living conditions or following 1week of bed rest (both P>0.05). Greater increases in GSSG concentration were associated with greater skeletal muscle mass loss following bed rest (r=-0.49, P<0.05). In older men, only submaximal mitochondrial oxidative phosphorylation (corrected for mitochondrial content) was positively associated with myofibrillar protein synthesis rates during exercise training (r=0.72, P<0.05). However, changes in oxidative phosphorylation and H2O2 emission were not associated with changes in skeletal muscle mass following training (both P>0.05). Additionally, MCAT mice displayed no differences in myofibrillar (2.62±0.22 vs. 2.75±0.15%/day) and sarcoplasmic (3.68±0.35 vs. 3.54±0.35%/day) protein synthesis rates when compared with wild-type mice (both P>0.05). Mitochondrial oxidative phosphorylation and reactive oxygen emission do not seem to represent key factors regulating muscle protein synthesis or muscle mass regulation across the spectrum of physical activity.

Serum multi-omics analysis in hindlimb unloading mice model: Insights into systemic molecular changes and potential diagnostic and therapeutic biomarkers

Microgravity, in space travel and prolonged bed rest conditions, induces cardiovascular deconditioning along with skeletal muscle mass loss and weakness. The findings of microgravity research may also aid in the understanding and treatment of human health conditions on Earth such as muscle atrophy, and cardiovascular diseases. Due to the paucity of biomarkers and the unknown underlying mechanisms of cardiovascular and skeletal muscle deconditioning in these environments, there are insufficient diagnostic and preventative measures. In this study, we employed hindlimb unloading (HU) mouse model, which mimics astronauts in space and bedridden patients, to first evaluate cardiovascular and skeletal muscle function, followed by proteomics and metabolomics LC-MS/MS-based analysis using serum samples. Three weeks of unloading caused changes in the function of the cardiovascular system in c57/Bl6 mice, as seen by a decrease in mean arterial pressure and heart weight. Unloading for three weeks also changed skeletal muscle function, causing a loss in grip strength in HU mice and atrophy of skeletal muscle indicated by a reduction in muscle mass. These modifications were partially reversed by a two-week recovery period of reloading condition, emphasizing the significance of the recovery process. Proteomics analysis revealed 12 dysregulated proteins among the groups, such as phospholipid transfer protein, Carbonic anhydrase 3, Parvalbumin alpha, Major urinary protein 20 (Mup20), Thrombospondin-1, and Apolipoprotein C-IV. On the other hand, metabolomics analysis showed altered metabolites among the groups such as inosine, hypoxanthine, xanthosine, sphinganine, l-valine, 3,4-Dihydroxyphenylglycol, and l-Glutamic acid. The joint data analysis revealed that HU conditions mainly impacted pathways such as ABC transporters, complement and coagulation cascades, nitrogen metabolism, and purine metabolism. Overall, our results indicate that microgravity environment induces significant alterations in the function, proteins, and metabolites of these mice. These observations suggest the potential utilization of these proteins and metabolites as novel biomarkers for assessing and mitigating cardiovascular and skeletal muscle deconditioning associated with such conditions.

State of the Retina and Optic Nerve in 21-Day Head-Down Tilt Bed Rest

Studies in conditions of head-down tilt bed rest are widely used experiments which imitate redistribution of body fluids similar to the redistribution of fluid media in microgravity. To study the mechanism of development of spaceflight-associated neuro-ocular syndrome (SANS) in head-down tilt bed rest studies scientists have evaluated, among other things, participants’ visual system parameters. The main symptom of SANS is an edema of an optic disc and a retina. To date, the results describing the influence of head-down tilt bed rest on the visual system are ambiguous, which determines the relevance of further research. The aim of the study is to analyze retinal morphometry in the optic disc area and macular area in participants before and after 21-day head-down tilt bed rest. The study was performed using an optical coherence tomography with angiography function (Optovue RTVue XR Avanti System) before and after 21-days of head-down tilt bed rest. In 4 participants (8 eyes) (men, mean age ± standard deviation: 29.3 ± 3.9 years) the macular zone and optic disc area were evaluated according to standard scanning modes. To analyze the values obtained, we used mean tendency scores, mean comparison criteria, and graphical analysis. The results of the retinal thickness in the optic disc zone were consistent with those of other researchers, indicating a possible increase in retinal thickness, but our results did not reach the level of statistical significance. A statistically significant thickening of the retina in the macular zone was shown for the first time, but the increase is significantly less in amplitude than the thickening of the nerve fiber layer in the optic disc zone. Analysis of vascular density under head-down tilt bed rest conditions was performed for the first time both for the optic disc zone and the macula zone, but additional studies are required to obtain steady conclusions. For the first time, an increase in retinal thickness in the macula zone in participants of head-down tilt bed rest experiments was shown; for the optic disc zone, data consistent with the results of other researchers were obtained. For the first time, angiographic data were obtained for the macula and optic disk areas, but the obtained differences in vascular density did not reach the level of statistical significance.

Task performance with touchscreen interfaces under conditions of head-down tilt bed rest

The application of touchscreen-based interfaces in space travel has become increasingly common. As space travel greatly depends on efficient human performance, understanding how conditions during space missions affect performance is crucial. Prior research has demonstrated the adverse effects of microgravity in various performance tasks. While these effects have been studied in tasks involving non-interactive objects or “conventional” input modalities, few studies have examined how these findings transfer to touchscreen-based interfaces. The present study investigated changes in performance with a touchscreen-based interface under head-down tilt bed rest conditions (HDT). 24 participants performed multidirectional tapping tasks in a 60-day HDT study (− 6° head-down tilt position) at six subsequent points in time: 12 days prior to HDT, at 5, 21, and 56 days in HDT, and 4 and 90 days following HDT. Results show that the relationship between Movement Time and task difficulty expressed by Fitts’ law remains stable in HDT conditions. Moreover, analyses revealed elevated Error Rate and Touch Duration during HDT compared to baseline. Improvements in Throughput and Movement Time can be most likely attributed to practice effects. Future research directions motivated by the study results are discussed.

Objective Evidence for the Effectiveness of Single-session Treatment with a Spinal Thermal Massage Device : A Pilot Study

Individuals often report significant relief from pain and stress even after a single session of massage therapy; however, no previous studies have provided objective evidence supporting the effectiveness of a solitary massage therapy session. In the present study, we aimed to investigate the effectiveness of one-time treatment with a spinal thermal massage device reported to exert the same therapeutic effects as massage therapy in terms of pain reduction and stress relief. A man with chronic low back pain (LBP) underwent two rounds of experiments involving spinal massage treatment and bed rest, respectively. Pain was assessed using a visual analog scale, and heart rate variability (HRV) was measured in real-time to examine autonomic nervous system (ANS) activity. Blood samples were obtained at five points during each round of the experiment to examine changes in cortisol, epinephrine, and norepinephrine. Spinal massage significantly reduced pain and enhanced parasympathetic activity when compared with the bed rest condition. In addition, both epinephrine and norepinephrine levels were lower following spinal massage than following bed rest. These results are consistent with the reported effects of conventional massage therapy and support the effectiveness of one-time treatment using a spinal thermal massage device.

Long-duration head down bed rest as an analog of microgravity: Effects on the static perception of upright

BACKGROUND:Humans demonstrate many physiological changes in microgravity for which long-duration head down bed rest (HDBR) is a reliable analog. However, information on how HDBR affects sensory processing is lacking.OBJECTIVE:We previously showed [25] that microgravity alters the weighting applied to visual cues in determining the perceptual upright (PU), an effect that lasts long after return. Does long-duration HDBR have comparable effects?METHODS:We assessed static spatial orientation using the luminous line test (subjective visual vertical, SVV) and the oriented character recognition test (PU) before, during and after 21 days of 6° HDBR in 10 participants. Methods were essentially identical as previously used in orbit [25].RESULTS:Overall, HDBR had no effect on the reliance on visual relative to body cues in determining the PU. However, when considering the three critical time points (pre-bed rest, end of bed rest, and 14 days post-bed rest) there was a significant decrease in reliance on visual relative to body cues, as found in microgravity. The ratio had an average time constant of 7.28 days and returned to pre-bed-rest levels within 14 days. The SVV was unaffected.CONCLUSIONS:We conclude that bed rest can be a useful analog for the study of the perception of static self-orientation during long-term exposure to microgravity. More detailed work on the precise time course of our effects is needed in both bed rest and microgravity conditions.

Ultrasonic Backscatter Measurements of Human Cortical and Trabecular Bone Densities in a Head-Down Bed-Rest Study

This study aims to investigate the feasibility of quantitative ultrasonic backscatter in evaluating human cortical and trabecular bone densities in vivo based on a head-down-tilt bed rest study, with 36 participants tested through 90 d of bed rest and 180 d of recovery. Backscatter measurements were performed using an ultrasonic backscatter bone diagnostic instrument. Backscatter parameters were calculated with a dynamic signal-of-interest method, which was proposed to ensure the same ultrasonic interrogated volume in cortical and trabecular bones. The backscatter parameters exhibited significant correlations with site-matched bone densities provided by high-resolution peripheral quantitative computed tomography (0.33 < |R| < 0.72, p < 0.05). Some bone densities and backscatter parameters exhibited significant changes after the 90-d bed rest. The proposed method can be used to characterize bone densities, and the portable ultrasonic backscatter bone diagnostic device might be used to non-invasively reveal mean bone loss (across a group of people) after long-term bed rest and microgravity conditions of spaceflight missions.

Abaloparatide treatment increases bone formation, bone density and bone strength without increasing bone resorption in a rat model of hindlimb unloading.

Disuse osteoporosis can result from prolonged bed rest, paralysis, casts, braces, fractures and other conditions. Abaloparatide (ABL) is a PTHrP analog that increases bone density and strength by stimulating osteogenesis with limited effects on bone resorption. We examined skeletal responses to abaloparatide in young adult male rats with normal weight-bearing and with hindlimb unloading via a pelvic harness. Rats were allocated to four groups (10-12 per group): normal weight-bearing plus vehicle treatment (CON-VEH), normal weight-bearing plus ABL treatment (CON-ABL), hindlimb-unloading plus vehicle (HLU-VEH), or hindlimb-unloading plus ABL (HLU-ABL). Rats received ABL (25μg/kg/day, s.c.) or vehicle throughout the 28-day unloading period and were then sacrificed, at which time HLU-VEH rats exhibited reduced bone formation and significant deficits in tibial, femoral, and vertebral bone mass compared with CON-VEH. ABL treatment increased serum osteocalcin in CON and HLU animals while having no effect on the osteoclast marker TRACP-5b. Longitudinal peripheral quantitative computed tomography (pQCT) indicated that ABL increased trabecular and cortical bone mass in the tibia. ABL was also associated with improved trabecular and cortical bone mass and architectural parameters at the femur, tibia, and vertebrae by μCT. Tibial histomorphometry indicated increased trabecular and endocortical bone formation with HLU-ABL versus HLU-VEH and with CON-ABL versus CON-VEH, and ABL was also associated with lower trabecular and endocortical osteoclast surfaces. Vertebral finite element analysis indicated higher ultimate load and stiffness for CON-ABL versus CON-VEH and for HLU-ABL versus HLU-VEH. In summary, ABL was associated with improved trabecular and cortical bone density and architecture in normal weight-bearing and hindlimb-unloaded rats, with higher bone formation and no difference in bone resorption. ABL was also associated with improved bone biomechanical parameters. These results provide rationale for investigating the ability of abaloparatide to prevent or treat disuse osteoporosis in humans.

Pericyte transplantation improves skeletal muscle recovery following hindlimb immobilization.

Conditions of extended bed rest and limb immobilization can initiate rapid and significant loss of skeletal muscle mass and function. Physical rehabilitation is standard practice following a period of disuse, yet mobility may be severely compromised, and recovery is commonly delayed or incomplete in special populations. Thus, a novel approach toward recovery of muscle mass is highly desired. Pericytes [neuron-glial antigen 2 (NG2)+CD31-CD45- (Lineage- [Lin-]) and CD146+Lin-] demonstrate capacity to facilitate muscle repair, yet the ability to enhance myofiber growth following disuse is unknown. In the current study, 3-4-mo-old mice were unilaterally immobilized for 14 d (IM) or immobilized for 14 d followed by 14 d of remobilization (RE). Flow cytometry and targeted gene expression analyses were completed to assess pericyte quantity and function following IM and RE. In addition, a transplantation study was conducted to assess the impact of pericytes on recovery. Results from targeted analyses suggest minimal impact of disuse on pericyte gene expression, yet NG2+Lin- pericyte quantity is reduced following IM (P < 0.05). Remarkably, pericyte transplantation recovered losses in myofiber cross-sectional area and the capillary-to-fiber ratio following RE, whereas deficits remained with vehicle alone (P = 0.01). These findings provide the first evidence that pericytes effectively rehabilitate skeletal muscle mass following disuse atrophy.-Munroe, M., Dvoretskiy, S., Lopez, A., Leong, J., Dyle, M. C., Kong, H., Adams, C. M., Boppart, M. D. Pericyte transplantation improves skeletal muscle recovery following hindlimb immobilization.

Mitochondrial Quality Control Regulation by p53 During Disuse‐Induced Atrophy

Chronic muscle disuse, as observed in conditions of aging, prolonged bedrest, or limb immobilization, contributes to progressive atrophy of the affected skeletal muscle, and a reduction in mitochondrial content. These alterations in muscle mass and aerobic potential have broader consequences on mobility, strength and overall metabolic health. At the molecular level, chronic disuse results in increased intracellular reactive oxygen species (ROS) levels and elevated protein degradation. p53 is a well‐known transcriptional regulator that responds rapidly to perturbations in the cellular environment to activate various pathways in order to reestablish homeostasis. Previous work has illustrated a role for p53 in skeletal muscle mitochondrial maintenance as well as a contribution to muscle atrophy following chronic disuse. Our investigation focused on the necessity of p53 in mediating mitochondrial quality control (MQC) and muscle atrophy following 3 and 7 days of denervation‐induced muscle disuse in both wildtype (WT) and p53 muscle‐specific knockout (mKO) mice. Tibialis anterior (TA) mass was significantly reduced by 16% following 7 days of denervation in WT animals, however this was attenuated to only a 7% reduction in the mKO mice. Genotype had no effect on changes in mitochondrial content as both WT and mKO animals exhibited similar reductions (10–13%) in COX Activity by 7 days of denervation. Despite similar changes in mitochondrial content, there were divergent responses in mitochondrial function, assessed via O‐2 consumption and ROS emission using high‐resolution respirometry. Denervation resulted in impaired respiration in both genetic backgrounds, however we observed a trend for further decrements in the mKO mice as well as concomitant blunting of ROS generation following 7 days. To examine the regulation of MQC, we measured nuclear and mitochondrial localization of the transcriptional regulator PGC‐1α, as well as markers of autophagy/mitophagy, lysosomal biogenesis, the mitochondrial unfolded protein response (UPRmt) and apoptosis. We observed no effect of 3 days of denervation in any of the MQC markers. Following 7 days, nuclear PGC‐1α protein expression was elevated nearly 2‐fold in the denervated muscle of mKO mice, whereas WT animals displayed no change. Conversely, mitochondrial PGC‐1α protein expression was reduced almost 50% in WT denervated muscle but was maintained in the mKO tissue. Moreover, chronic disuse resulted in 3–6‐fold increases in the autophagy/mitophagy proteins p62, LC3‐II, PINK1 and Parkin in isolated mitochondrial fractions from WT mice, but mKO animals showed a diminished induction of these markers. In contrast, lysosomal proteins Lamp1 and Cathepsin D were induced by 40–50% in mKO muscle compared to WT animals. Similarly, UPRmt proteins mtHSP70, LonP, and ATF5 were elevated 15–30% higher in the denervated muscle of mKO animals, while the apoptotic marker BAX and BID were attenuated relative to WT counterparts. Together, these results suggest a dysregulation of MQC in the absence of p53 within skeletal muscle subjected to denervation, and indicate a potential role of p53 in contributing to organelle maintenance during muscle atrophy.Support or Funding InformationWork supported by NSERC, Canada.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of mechanical bed massage on biochemical markers of exercise-induced back muscle fatigue in athletes: A randomized controlled trial.

Many previous studies have explored the effects of manual massage on back muscle fatigue, and most of the mechanical massage techniques imitate manual massage. However, it is unknown whether mechanical and manual massage have the same functions for exercise-induced back muscle fatigue. To investigate the effects of mechanical bed massage on the biochemical markers of exercise-induced back muscle fatigue in male collegiate athletes. Twenty-eight male collegiate athletes who met the experimental criteria were recruited in this randomized controlled trial, and randomly assigned to a mechanical bed massage group (experimental group) or resting group (control group). The subjects performed eight bouts of reverse sit-up in the prone position and received 20 minutes of the intervention. Creatine kinase, blood lactate, and serum cortisol levels were measured at baseline, after fatigue, after intervention, and after 24 hours. The level of serum cortisol of the control group was significantly higher than that of the experimental group after the intervention (p< 0.05). The comparison of the two groups for blood lactate levels showed no significant differences at any of the measurement time-points (p> 0.05). There was no significant difference in creatine kinase levels immediately after the intervention (p> 0.05), but a significant difference in creatine kinase level was observed between the two groups 24 hours later (p< 0.05). Significant differences were observed between mechanical bed massage and rest condition on serum cortisol and creatine kinase for exercise-induced muscle fatigue. Therefore, mechanical bed massage may reduce stress and muscle damage for the athlete after training or competition.

Effects of Hypoxia and Bed Rest on Markers of Cardiometabolic Risk: Compensatory Changes in Circulating TRAIL and Glutathione Redox Capacity.

In chronic diseases, hypoxia and physical inactivity are associated with atherosclerosis progression. In contrast, a lower mortality from coronary artery disease and stroke is observed in healthy humans residing at high altitude in hypoxic environments. Eleven young, male volunteers completed the following 10-day campaigns in a randomized order: hypoxic ambulatory, hypoxic bed rest and normoxic bed rest. Before intervention, subjects were evaluated in normoxic ambulatory condition. Normobaric hypoxia was achieved in a hypoxic facility simulating 4000 m of altitude. Following hypoxia, either in bed rest or ambulatory condition, markers of cardiometabolic risk shifted toward a more atherogenic pattern consisting of: (a) lower levels of total HDL cholesterol and HDL2 sub-fraction and decreased hepatic lipase; (b) activation of systemic inflammation, as determined by C-reactive protein and serum amyloid A; (c) increased plasma homocysteine; (d) decreased delta-5 desaturase index in cell membrane fatty acids, a marker of insulin sensitivity. Bed rest and hypoxia additively decreased total HDL and delta-5 desaturase index. In parallel to the pro-atherogenic effects, hypoxia activated selected anti-atherogenic pathways, consisting of increased circulating TNF-related apoptosis-inducing ligand (TRAIL), a protective factor against atherosclerosis, membrane omega-3 index and erythrocyte glutathione availability. Hypoxia mediated changes in TRAIL concentrations and redox glutathione capacity (i.e., GSH/GSSG ratio) were greater in ambulatory conditions (+34 ± 6% and +87 ± 31%, respectively) than in bed rest (+17 ± 7% and +2 ± 27% respectively). Hypoxia-induced cardiometabolic risk is blunted by moderate level of physical activity as compared to bed rest. TRAIL and glutathione redox capacity may contribute to the positive interaction between physical activity and hypoxia.Highlights:– Hypoxia and bed rest activate metabolic and inflammatory markers of atherogenesis.– Hypoxia and physical activity activate selected anti-atherogenic pathways.– Hypoxia and physical activity positive interaction involves TRAIL and glutathione.

Role of rehabilitation in the elderly after an acute event: insights from a real-life prospective study in the subacute care setting.

Any acute event, either primary or secondary to a chronic disease, is generally followed by some degree of physical impairment. Subacute care (SAC) represents one of the inpatient intermediate care settings aimed at completing recovery and restoring functional capacity. Debate exists on the role of the rehabilitation treatment in the SAC setting. The aim of this study was to compare the outcomes of patients managed in two different SAC Units where A) patients undergo an individualized rehabilitation program on top of optimal medical therapy (OMT) B) patients receive OMT only. Real-life prospective study. SAC units. Seventy-five chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD) patients transferred after an acute hospitalization. Upon SAC admission, the following scales were obtained: cumulative illness rating scale comorbidity and severity (CIRSC and CIRSS), mini mental state examination (MMSE), Performance-Oriented Mobility Assessment (POMA), Barthel Index (BI), the 10-meter walking test (10MWT). Pre-admission BI was also collected based on history. Upon SAC discharge, BI, POMA, and 10MWT were repeated. Patients (44 in Group A, 31 in Group B) were similar with regard to age, gender, MMSE, clinical complexity, pre-admission BI, admission 10MWT, POMA, and bedrest conditions. Admission BI was lower in Group A. In both groups BI was lower when compared to the respective pre-admission score. Upon discharge, Group A patients were characterized by a higher BI and POMA compared to Group B. Indeed, BI and POMA improved at discharge only in Group A patients. Only this latter group reached the pre-morbid BI. Upon discharge the number of bedrest patients decreased only in Group A. The percentage of patients discharged home was also much higher in Group A, while a greater number of Group B patients were transferred to a rehabilitation ward or were enrolled in an integrated home care assistance program. In a real-life prospective experience, a better outcome is demonstrated in elderly CHF and COPD patients undergoing a rehabilitative approach during their in-hospital SAC stay. An individualized rehabilitation program should integrate medical treatment of CHF and BPCO patients in the SAC setting. This approach demonstrates a better cost-effectiveness management of these patients.

Hypoxia Exacerbates Negative Emotional State during Inactivity: The Effect of 21 Days Hypoxic Bed Rest and Confinement.

Hypoxia and confinement have both been shown to influence emotional state. It is envisaged that the inhabitants of future planetary habitats will be exposed to concomitant confinement, reduced gravity and hypoxia. We examined the independent and combined effects of a 21-day inactivity/unloading and normobaric hypoxia under confined conditions on various psychological factors. Eleven healthy men participated in three 21-day experimental campaigns designed in a cross-over manner: (1) Normobaric hypoxic ambulatory confinement, (2) Normobaric hypoxic bed rest and (3) Normobaric normoxic bed rest. The Profile of Mood States, and the Positive and Negative Affect Schedule were employed to assess the participants' psychological responses before (Pre), during (Day 7, Day 14, and Day 21) and after (Post) the confinements. The most negative psychological profile appeared on days 14 and 21 of the hypoxic bed rest campaign. A significant increase in depression, tension, and confusion was noted on days 14 and 21 of the hypoxic bed rest condition. Concomitantly, a decrease, albeit not statistically significant, in positive psychological responses was observed. The psychological profile returned to the initial level at Post following all confinements. These data suggest that the combined effect of hypoxia and bed rest induced the most negative effects on an individual's mood. However, significant intra- and inter-individual differences in psychological responses were noted and should be taken into consideration.

Virtual reality as a countermeasure for physical training in bed rest and artificial gravity conditions.

Virtual reality as a countermeasure for physical training in bed rest and artificial gravity conditions.

Incretion of Insulin by Pancreas and Its Inactivation in Women during Long-Term Head-down Tilt Bed Rest

An increase in insular activity in response to hyperglycemia when performing a glucose tolerance test (GTT) during normal physical activity in eight women volunteers was found to be associated with increased blood concentrations of insulin provided by an increase in secretion rate and a decrease in inactivation rate. After 81 days of stay in long-term –6° head-down tilt bed rest (bed rest), flattened glycemic curves (with low hyperglycemic lifting) observed during the GTT, what was indicated high insular activity. An increase in the insular activity was evidencing also by a smaller peak of the blood concentration of glucose from 5 min after intravenous nfusion of 20 mL of 40% glucose solution at 120 minute of the GTT. In bed rest on empty stomach no significant changes in the concentrations of insulin and C-peptide were observed. The dynamics of hormone during the GTT was showed that the appearance of flattened glycemic curves when performing GTT during bed rest was associated with more pronounced, than under the usual conditions, an increase in insulin concentration in response to hyperglycemia. An increase in the blood insulin concentration when performing GTT in bed rest was mainly provided by increased hormone secretion rate in the pancreas, but not by a decrease in its inactivation rate. If you use regular exercises for prevention of hypokinesia under conditions of bed rest, an increase in insulin concentration during GTT was mainly provided by a decrease in its inactivation rate and not by an increase in secretion rate.

Daytime bright light exposure, metabolism, and individual differences in wake and sleep energy expenditure during circadian entrainment and misalignment

Daytime light exposure has been reported to impact or have no influence on energy metabolism in humans. Further, whether inter-individual differences in wake, sleep, 24 h energy expenditure, and RQ during circadian entrainment and circadian misalignment are stable across repeated 24 h assessments is largely unknown. We present data from two studies: Study 1 of 15 participants (7 females) exposed to three light exposure conditions: continuous typical room ~100 lx warm white light, continuous ~750 lx warm white light, and alternating hourly ~750 lx warm white and blue-enriched white light on three separate days in a randomized order; and Study 2 of 14 participants (8 females) during circadian misalignment induced by a simulated night shift protocol. Participants were healthy, free of medical disorders, medications, and illicit drugs. Participants maintained a consistent 8 h per night sleep schedule for one week as an outpatient prior to the study verified by wrist actigraphy, sleep diaries, and call-ins to a time stamped recorder. Participants consumed an outpatient energy balance research diet for three days prior to the study. The inpatient protocol for both studies consisted of an initial sleep disorder screening night. For study 1, this was followed by three standard days with 16 h scheduled wakefulness and 8 h scheduled nighttime sleep. For Study 2, it was followed by 16 h scheduled wake and 8 h scheduled sleep at habitual bedtime followed by three night shifts with 8 h scheduled daytime sleep. Energy expenditure was measured using whole-room indirect calorimetry. Constant posture bedrest conditions were maintained to control for energy expenditure associated with activity and the baseline energy balance diet was continued with the same exact meals across days to control for thermic effects of food. No significant impact of light exposure was observed on metabolic outcomes in response to daytime light exposure. Inter-individual variability in energy expenditure was systematic and ranged from substantial to almost perfect consistency during both nighttime sleep and circadian misalignment. Findings show robust and stable trait-like individual differences in whole body 24 h, waking, and sleep energy expenditure, 24 h respiratory quotient—an index of a fat and carbohydrate oxidation—during repeated assessments under entrained conditions, and also in 24 h and sleep energy expenditure during repeated days of circadian misalignment.

Pengaruh ROM Pasif Terhadap Laju Pernapasan Dan SpO2 Pada Pasien Post Craniotomy Di ICU RSUD Dr. Moewardi Surakarta Tahun 2015

Abstract : Passive ROM, Respiration Rate, Oxygen Saturation, Post Craniotomy Patient, ICU. Patient with bedrest condition will have inteference of muscle streght, its needed implementation to reduce. One of them is medic rehabilitation ROM (Range of Motion) by active and passive movement. One of purpose of ROM Passive on critical patient in ICU is to stable cardiovascular function, respiration and oxygen saturation. To know the effect of passive ROM to respiration rate and oxygen saturation on post craniotomy patient in ICU RSUD Dr. Moewardi. The research using pre eksperimental design. Desain using One Group pre-post test design. Sample on the research using purposive sampling and 30 respondences. Result research of passive ROM to respiration rate have been gotten data there are changes respiration rate before and after, have enhancement 3,967. Data oxygen saturation before and after 1,333. There are effect passive ROM to respiration rate and oxygen saturation.

Posture Used in fMRI-PET Elicits Reduced Cortical Activity and Altered Hemispheric Asymmetry with Respect to Sitting Position: An EEG Resting State Study.

Horizontal body position is a posture typically adopted for sleeping or during brain imaging recording in both neuroscience experiments and diagnostic situations. Recent literature showed how this position and similar ones with head down are associated to reduced plasticity, impaired pain and emotional responses. The present study aimed at further understanding the decrease of cortical activity associated with horizontal body position by measuring high-frequency EEG bands – typically associated with high-level cognitive activation – in a resting state experimental condition. To this end, two groups of 16 female students were randomly assigned to either sitting control (SC) or 2-h horizontal Bed Rest condition (hBR) while EEG was recorded from 38 scalp recording sites. The hBR group underwent several body transitions, from sitting to supine, and from supine to sitting. Results revealed a clear effect of horizontal posture: the hBR group showed, compared to its baseline and to SC, reduced High-Beta and Gamma EEG band amplitudes throughout the 2-h of hBR condition. In addition, before and after the supine condition, hBR group as well as SC exhibited a greater left vs. right frontal activation in both EEG bands while, on the contrary, the supine position induced a bilateral and reduced activation in hBR participants. The cortical sources significantly more active in SC compared with hBR participants included the left Inferior Frontal Gyrus and left Insula. Results are discussed in relation to the differences among neuroimaging methods (e.g., fMRI, EEG, NIRS), which can be partially explained by posture-induced neural network changes.

Exercise Altered the Skeletal Muscle MicroRNAs and Gene Expression Profiles in Burn Rats With Hindlimb Unloading.

This study investigated microRNA and target gene profiles under different conditions of burn, bed rest, and exercise training. Male Sprague-Dawley rats (n = 48) were assigned to sham ambulatory, sham hindlimb unloading, burn ambulatory, or burn plus hindlimb unloading groups. Rats received a 40% TBSA scald burn or sham treatments and were ambulatory or hindlimb unloaded. Rats were further assigned to exercise or no exercise. Plantaris tissues were harvested on day 14 and pooled to analyze for microRNA and gene expression profiles. Compared with the sham ambulatory-no exercise group, 73, 79, and 80 microRNAs were altered 2-fold in the burn ambulatory, sham hindlimb unloading, and burn hindlimb unloading groups, all with no exercise, respectively. More than 70% of microRNAs were upregulated in response to burn and hindlimb unloading, whereas 60% microRNA of the profile decreased in hindlimb unloaded burn rats with exercise training. MiR-182 was the most affected in rat muscle. Gene ontology biological process and pathway analysis showed that the oxidative stress pathway was most stimulated in the hindlimb unloaded burn rats; while in response to exercise training, all genes in related pathways such as hypermetabolic, inflammation, and blood coagulation were alleviated. MicroRNAs and transcript gene profiles were altered in burn and hindlimb unloading groups, with additive effects on hindlimb unloaded burn rats. The altered genes' signal pathways were associated with muscle mass loss and function impairment. Muscle improvement with exercise training was observed in gene levels with microRNA alterations as well.