Ambulation Recovery Research Articles

Exercise recovery increases skeletal muscle H2O2 emission and mitochondrial respiratory capacity following two-weeks of limb immobilization

Extended periods of skeletal muscle disuse result in muscle atrophy. Following limb immobilization, increased mitochondrial reactive oxygen species (ROS) production may contribute to atrophy through increases in skeletal muscle protein degradation. However, the effect of skeletal muscle disuse on mitochondrial ROS production remains unclear. This study investigated the effect of immobilization, followed by two subsequent periods of restored physical activity, on mitochondrial H2O2 emissions in adult male skeletal muscle. Middle-aged men (n = 30, 49.7 ± 3.84 y) completed two weeks of unilateral lower-limb immobilization, followed by two weeks of baseline-matched activity, consisting of 10,000 steps a day, then completed two weeks of three times weekly supervised resistance training. Vastus lateralis biopsies were taken at baseline, post-immobilization, post-ambulatory recovery, and post-resistance-training. High-resolution respirometry was used simultaneously with fluorometry to determine mitochondrial respiration and hydrogen peroxide (H2O2) production in permeabilized muscle fibres. Mitochondrial H2O2 emission with complex I and II substrates, in the absence of ADP, was greater following immobilization, however, there was no effect on mitochondrial respiration. Both ambulatory recovery and resistance training, following the period of immobilization, increased in mitochondrial H2O2 emissions. These data demonstrated that 2 weeks of immobilization increases mitochondrial H2O2 emissions, but subsequent retraining periods of ambulatory recovery and resistance training also led to in robust increases in mitochondrial H2O2 emissions in skeletal muscle.

Microendoscopy-Assisted Minimally Invasive Versus Open Transforaminal Lumbar Interbody Fusion for Lumbar Degenerative Diseases: 5-Year Outcomes

We sought to evaluate 5-year outcomes between microendoscopy-assisted minimally invasive (MIS) and open transforaminal lumbar interbody fusion (TLIF). Sixty single-level MIS and open surgeries were performed (30 patients in either group). Perioperative parameters including operative duration, intraoperative estimated blood loss, fluoroscopy time, postoperative analgesic usage, ambulatory time, and complications were recorded. Visual analog scale (back and leg), Japanese Orthopaedics Association score, and Oswestry Disability Index were obtained. Finally, self-evaluation of surgical outcomes (modified MacNab criteria), interbody fusion rate (Bridwell grade 1), and prevalence of adjacent segment degeneration were assessed. Intraoperative estimated blood loss and postoperative analgesia usage were reduced in the MIS group, and patients undergoing microendoscopy-assisted MIS-TLIF ambulated earlier than those receiving open TLIF postoperatively. Nevertheless, surgical duration and fluoroscopy time were prolonged in the MIS group. Complication incidences were similar in both groups. Visual analog scale (back and leg), Japanese Orthopaedics Association, and Oswestry Disability Index were improved at 1 month, 2 years, and 5 years postoperatively in both groups when compared with preoperative scores. Significant improvements in these scores were found in the MIS group at 1 month postoperatively, while at 2 years and 5 years postoperatively, both groups revealed comparable aforementioned scores. Excellent and perfect scale rating, interbody fusion rate, and adjacent segment degeneration prevalence between the groups were almost similar. Microendoscopy-assisted MIS-TLIF is comparable with open TLIF in terms of 5-year outcomes with additional benefits of reduced intraoperative iatrogenic injury, decreased initial pain, minimized activity restrictions, and accelerated ambulation recovery after surgery.

Osteossíntese com placa óssea em u ma macaca bugio-preto (Alouatta caraya)

The surgical treatment for the correction of fractures in wild animals requires the correct selection of the osteosynthesis method to be used, in such a way as to achieve the reduction and stabilization of the fracture focus, and an adequate evolution during the postoperative period. The purpose of this report was to describe and monitor bone healing in a tibiofibular oblique proximal diaphyseal fracture with a 2.7 mm bone plate implant in a female black howler monkey of the Alouatta caraya species. In the follow-up of the patient’s evolution, the radiographic images showed evidence of consolidation of both bones and stable fixation of the plate, providing early ambulation and complete recovery of limb function.

Voluntary wheel running increases satellite cell abundance and improves recovery from disuse in gastrocnemius muscles from mice.

Reloading of atrophied muscles after hindlimb suspension unloading (HSU) can induce injury and prolong recovery. Low-impact exercise, such as voluntary wheel running, has been identified as a nondamaging rehabilitation therapy in rodents, but its effects on muscle function, morphology, and satellite cell activity after HSU are unclear. This study tested the hypothesis that low-impact wheel running would increase satellite cell proliferation and improve recovery of muscle structure and function after HSU in mice. Young adult male and female C57BL/6 mice ( n = 6/group) were randomly placed into five groups. These included HSU without recovery (HSU), normal ambulatory recovery for 14 days after HSU (HSU+NoWR), and voluntary wheel running recovery for 14 days after HSU (HSU+WR). Two control groups were used: nonsuspended mouse cage controls (Control) and voluntary wheel running controls (ControlWR). Satellite cell activation was evaluated by providing mice 5-bromo-2'-deoxyuridine (BrdU) in their drinking water. As expected, HSU significantly reduced in vivo maximal force, decreased in vivo fatigability, and decreased type I and IIa myosin heavy chain (MHC) abundance in plantarflexor muscles. HSU+WR mice significantly improved plantarflexor fatigue resistance, increased type I and IIa MHC abundance, increased fiber cross-sectional area, and increased the percentage of type I and IIA muscle fibers in the gastrocnemius muscle. HSU+WR mice also had a significantly greater percentage of BrdU-positive and Pax 7-positive nuclei inside muscle fibers and a greater MyoD-to-Pax 7 protein ratio compared with HSU+NoWR mice. The mechanotransduction protein Yes-associated protein (YAP) was elevated with reloading after HSU, but HSU+WR mice had lower levels of the inactive phosphorylated YAPserine127, which may have contributed to increased satellite cell activation with reloading after HSU. These results indicate that voluntary wheel running increased YAP signaling and satellite cell activity after HSU and this was associated with improved recovery. NEW & NOTEWORTHY Although satellite cell involvement in muscle remodeling has been challenged, the data in this study suggest that voluntary wheel running increased satellite cell activity and suppressed Yes-associated protein (YAP) protein relative to no wheel running and this was associated with improved muscle recovery of force, fatigue resistance, expression of type I myosin heavy chain, and greater fiber cross-sectional area after disuse.

Impact of dairy protein during limb immobilization and recovery on muscle size and protein synthesis; a randomized controlled trial.

Muscle disuse results in the loss of muscular strength and size, due to an imbalance between protein synthesis (MPS) and breakdown (MPB). Protein ingestion stimulates MPS, although it is not established if protein is able to attenuate muscle loss with immobilization (IM) or influence the recovery consisting of ambulatory movement followed by resistance training (RT). Thirty men (49.9 ± 0.6 yr) underwent 14 days of unilateral leg IM, 14 days of ambulatory recovery (AR), and a further six RT sessions over 14 days. Participants were randomized to consume an additional 20 g of dairy protein or placebo with a meal during the intervention. Isometric knee extension strength was reduced following IM (-24.7 ± 2.7%), partially recovered with AR (-8.6 ± 2.6%), and fully recovered after RT (-0.6 ± 3.4%), with no effect of supplementation. Thigh muscle cross-sectional area decreased with IM (-4.1 ± 0.5%), partially recovered with AR (-2.1 ± 0.5%), and increased above baseline with RT (+2.2 ± 0.5%), with no treatment effect. Myofibrillar MPS, measured using deuterated water, was unaltered by IM, with no effect of protein. During AR, MPS was increased only with protein supplementation. Protein supplementation did not attenuate the loss of muscle size and function with disuse or potentiate recovery but enhanced myofibrillar MPS during AR. NEW & NOTEWORTHY Twenty grams of daily protein supplementation does not attenuate the loss of muscle size and function induced by 2 wk of muscle disuse or potentiate recovery in middle-age men. Average mitochondrial but not myofibrillar muscle protein synthesis was attenuated during immobilization with no effect of supplementation. Protein supplementation increased myofibrillar protein synthesis during a 2-wk period of ambulatory recovery following disuse but without group differences in phenotype recovery.

Effects of robot-assisted minimally invasive transforaminal lumbar interbody fusion and traditional open surgery in the treatment of lumbar spondylolisthesis

Objective: To compare the clinical effects of robot-assisted minimally invasive transforaminal lumbar interbody fusion (TLIF) and traditional open TLIF in the treatment of lumbar spondylolisthesis. Methods: A total of 41 patients with lumbar spondylolisthesis accepted surgical treatment in Department of Spinal Surgery of Beijing Jishuitan Hospital From July 2015 to April 2016 were retrospectively analyzed. There were 16 cases accepted robot-assisted minimally invasive TLIF and 25 accepted traditional open TLIF. The operation time, X-ray radiation exposure time, perioperative bleeding, drainage volume, time of hospitalization, time for pain relief, time for ambulatory recovery, visual analogue scale (VAS), Oswestry disability index (ODI) and complications were compared. T test and χ(2) were used to analyze data. Results: There were no significant difference in gender, age, numbers, degrees, pre-operative VAS and ODI in spondylolisthesis (all P>0.05). Compared with traditional open TLIF group, the robot-assisted minimally invasive TLIF group had less perioperative bleeding ((187.5±18.4) ml vs. (332.1±23.5) ml), less drainage volume ((103.1±15.6) ml vs. (261.3±19.8) ml), shorter hospitalization ((7.8±1.9) days vs. (10.0±1.6) days), shorter time for pain relief ((2.8±1.0) days vs. (5.2±1.1) days), shorter time for ambulatory recovery ((1.7±0.9) days vs. (2.9±1.3) days) and less VAS of the third day postoperatively (2.2±0.9 vs. 4.2±2.4) (t=2.762-16.738, all P<0.05), but need more operation time ((151.3±12.3) minutes vs. (102.2±7.1) minutes) and more X-ray radiation exposure ((26.1±3.3) seconds vs. (5.5±2.1) seconds) (t=6.125, 15.168, both P<0.01). In both groups ODI was significantly lower in final follow-up than that of the pre-operation (t=12.215, 14.036, P<0.01). Intervertebral disc height of the final follow-up in both groups were significantly larger than that of the preoperation (robot-assisted minimally invasive TLIF group: (11.8 ± 2.8) mm vs. (7.5 ± 1.9) mm, traditional open TLIF group: (12.7 ± 2.5) mm vs. (7.9±2.0) mm), and so was the lumbar lordosis angle (robot-assisted minimally invasive TLIF group: (48.7±9.2)°vs. (39.6±7.9)°, traditional open TLIF group: (50.1±10.8)°vs. (41.4±8.8)°), the lordosis angle of the slippage segment (robot-assisted minimally invasive TLIF group: (18.7±5.6)°vs. (10.9±3.8)°, traditional open TLIF group: (17.6±6.1)°vs.(8.7±3.2)°) (t=4.128-16.738, all P<0.01). Slippage rate of the final follow-up in both groups were significantly smaller than those of the pre-operation (robot-assisted minimally invasive TLIF group: (5.3±2.3) % vs. (27.8±7.2) %, traditional open TLIF group: (6.6±2.8) % vs. (29.1±9.5) %) (t=11.410, 18.504, both P<0.01). There was no difference of the upper data between two groups (t=0.106-1.227, P>0.05). The results of the post-operative CT showed that the pedicle screws in the robot-assisted minimally invasive TLIF group were more precisely placed than traditional open TLIF group (χ(2)=4.247, P=0.039). The mean follow-up time was 8 months (ranging from 3 to 12 months). There were no significant difference in outcomes between the two groups (χ(2)=0.366, P=0.545). Conclusions: In the treatment of lumbar spondylolisthesis, Robot-assisted minimally invasive TLIF can lead to less perioperative bleeding, less post-operative pain, and quicker recovery than traditional open TLIF surgery, but it needs more operation time and radiation exposure.

High-Intensity Jump Training Is Tolerated during 60 Days of Bed Rest and Is Very Effective in Preserving Leg Power and Lean Body Mass: An Overview of the Cologne RSL Study.

PurposeSpace agencies are looking for effective and efficient countermeasures for the degrading effects of weightlessness on the human body. The aim of this study was to assess the effects of a novel jump exercise countermeasure during bed rest on vitals, body mass, body composition, and jump performance.Methods23 male participants (29±6 years, 181±6 cm, 77±7 kg) were confined to a bed rest facility for 90 days: a 15-day ambulatory measurement phase, a 60-day six-degree head-down-tilt bed rest phase (HDT), and a 15-day ambulatory recovery phase. Participants were randomly allocated to the jump training group (JUMP, n = 12) or the control group (CTRL, n = 11). A typical training session consisted of 4x10 countermovement jumps and 2x10 hops in a sledge jump system. The training group had to complete 5–6 sessions per week.ResultsPeak force for the reactive hops (3.6±0.4 kN) as well as jump height (35±4 cm) and peak power (3.1±0.2 kW) for the countermovement jumps could be maintained over the 60 days of HDT. Lean body mass decreased in CTRL but not in JUMP (-1.6±1.9 kg and 0±1.0 kg, respectively, interaction effect p = 0.03). Resting heart rate during recovery was significantly increased for CTRL but not for JUMP (interaction effect p<0.001).ConclusionParticipants tolerated the near-daily high-intensity jump training and maintained high peak forces and high power output during 60 days of bed rest. The countermeasure was effective in preserving lean body mass and partly preventing cardiac deconditioning with only several minutes of training per day.

Predictors for Ambulatory Recovery after Fixation of Intertrochanteric Fracture with Proximal Femoral Nail in the Elderly

Predictors for Ambulatory Recovery after Fixation of Intertrochanteric Fracture with Proximal Femoral Nail in the Elderly

Preoperative prediction for regaining ambulatory ability in paretic non-ambulatory patients with metastatic spinal cord compression.

Retrospective multicenter study. To analyze the predictive factors for postoperative ambulatory recovery in paretic non-ambulatory patients with metastatic spinal cord compression (MSCC). Japan. Eighty-two consecutive patients (74.4% men; mean age, 66.2 years) who could not walk before surgery due to cervical or thoracic MSCC and underwent posterior decompressive surgery between 2003 and 2014 were included. Patients were divided into two groups according to ambulatory status at 6 weeks after surgery: recovery (group R) and non-recovery (group NR). To evaluate the speed of progression of motor deficits, we assessed the period from onset of neurological symptoms to gait inability (T1). Fifty patients (61.0%) regained the ability to walk (group R). The period of T1 demonstrated a positive correlation with probability of ambulatory recovery (P=0.00; Kendall's tau-b=0.38), and a receiver operating characteristic curve analysis showed that the cutoff value of T1 was 5 days (area under the curve=0.72; P=0.001). In multivariate analysis, <6 days of T1 was one of the independent risk factors for failing to regain ambulatory ability (odds ratio, 8.74; P=0.00). The speed of progression of motor deficits can independently and powerfully predict the chance of postoperative ambulatory recovery as well as previously identified predictors. Since information about the speed of progression can be obtained easily by interviewing patients or family members, even if the patient is in an urgent state, our results will be helpful in clinical decision-making.

Transcranial Magnetic Stimulation and Diffusion Tensor Tractography for Evaluating Ambulation after Stroke.

Background and PurposeWe aimed to investigate the usefulness of combining transcranial magnetic stimulation (TMS) and diffusion tensor tractography (DTT) to evaluate corticospinal tract (CST) integrity and subsequently predict ambulatory function after middle cerebral artery (MCA) stroke.MethodsForty-three patients with first MCA stroke underwent TMS and DTT to evaluate CST integrity. Patients were classified into four groups according to the presence of motor-evoked potentials (MEPs) obtained from the tibialis anterior muscle and CST integrity. Motor impairment and functional status were assessed using the Fugl-Meyer Assessment, Functional Ambulation Category, and Korean modified Barthel Index, both at the time of admission and after 4 weeks of rehabilitation.ResultsPatients with the presence of both measurable MEPs and a preserved CST showed better motor recovery and ambulatory function than other groups at the 4-week follow-up. Intact CSTs were not visualized in patients without detectable MEPs. Among the patients displaying MEPs, those with preserved CSTs showed better recovery of paretic lower extremities.ConclusionsCombined assessment using TMS and DTT to evaluate CST integrity confers advantages in predicting motor and ambulation recovery in patients with MCA stroke.

Heat shock transcription factor 1-associated expression of slow myosin heavy chain in mouse soleus muscle in response to unloading with or without reloading.

The effects of heat shock transcription factor 1 (HSF1) deficiency on the fibre type composition and the expression level of nuclear factor of activated T cells (NFAT) family members (NFATc1, NFATc2, NFATc3 and NFATc4), phosphorylated glycogen synthase kinase 3α (p-GSK3α) and p-GSK3β, microRNA-208b (miR-208b), miR-499 and slow myosin heavy chain (MyHC) mRNAs (Myh7 and Myh7b) of antigravitational soleus muscle in response to unloading with or without reloading were investigated. HSF1-null and wild-type mice were subjected to continuous 2-week hindlimb suspension followed by 2- or 4-week ambulation recovery. In wild-type mice, the relative population of slow type I fibres, the expression level of NFATc2, p-GSK3 (α and β), miR-208b, miR-499 and slow MyHC mRNAs (Myh7 and Myh7b) were all decreased with hindlimb suspension, but recovered after it. Significant interactions between train and time (the relative population of slow type I fibres; P=0.01, the expression level of NFATc2; P=0.001, p-GSKβ; P=0.009, miR-208b; P=0.002, miR-499; P=0.04) suggested that these responses were suppressed in HSF1-null mice. HSF1 may be a molecule in the regulation of the expression of slow MyHC as well as miR-208b, miR-499, NFATc2 and p-GSK3 (α and β) in mouse soleus muscle.

Survival and Functional Outcomes after Hip Fracture among Nursing Home Residents

Following the implementation of a long-term care insurance system for the elderly in Korea, many nursing homes have been established and many more patients than ever before have been living at nursing homes. Despite the fact that this is a high-risk group vulnerable to hip fractures, no study has yet been conducted in Korea on hip fracture incidence rates and prognoses among patients residing at nursing homes. We recently studied 46 cases of hip fracture in nursing homes; more specifically, we investigated the most common conditions under which fractures occur, and examined the degree of recovery of ambulatory ability and the mortality within 1 yr. Among those who had survived after 1 yr, the number of non-functional ambulators increased from 8 hips before hip fracture to 19 hips at final post-fracture follow-up. These individuals showed poor recovery of ambulatory ability, and the number who died within one year was 11 (23.9%), a rate not significantly different from that among community-dwelling individuals. It was evident that hip-joint-fracture nursing home residents survived for similar periods of time as did those dwelling in the community, though under much more uncomfortable conditions. The main highlight of this report is that it is the first from Korea on nursing home residents' ambulatory recovery and one-year mortality after hip fracture. The authors believe that, beginning with the present study, the government should collect and evaluate the number of hips fractured at nursing facilities in order to formulate criteria that will help to enable all patients to select safer and better-quality nursing facilities for themselves or their family members.

Canonical Mitochondrial Biogenesis And Mitochondrial Translation Following Multiple Bouts Of Disuse

Muscular disuse affects a great number of people with sedentary lifestyles and/or chronic disease. Disuse has been shown to cause severe muscular atrophy and to disrupt mitochondrial quality. The mitochondrial genome encodes 13 proteins critical to oxidative phosphorylation for which the mitochondria contains its own equipment for mRNA translation. PURPOSE:To examine if disuse affects canonical mitochondrial biogenesis and mitochondrial mRNA translation, and if resistance exercise following bouts of unloading can promote biogenesis. METHODS:Sprague-Dawley rats were subjected to chronic disuse atrophy by hindlimb unloading (28-d, 1HU) followed by ambulatory recovery (56-d) with (1HU+EX) and without (1HU+REC) resistance exercise. To mimic repeated bouts of disuse animals were subjected to a second bout of HU (28-d, 2HU) and allowed ambulatory recovery with (2HU+EX) or without (2HU+REC) resistance exercise. Control (CON) animals were allowed normal cage activity throughout. Samples were analyzed for Pgc-1α, Tfam, Nrf2, Pparα, Tufm, and Taco1 mRNA content by real time RT-PCR. To test if disuse impacted mitochondrial biogenesis regulators a T-Test was performed between CON and 1HU groups, to test impact of reloading and exercise data were analyzed by one-way ANOVA across all groups with α set at P<0.05. RESULTS:Pgc-1α content was 59% and Nrf2 75% lower following disuse (1HU) compared to CON. 1HU+Ex exhibited 280% greater Pparα content and 278% greater Tfam content (p=0.013) compared to CON. Pgc-1α (80%), Pparα (208%), and Tfam (195%)contents were significantly greater with exercise recovery (1HU+Ex) than without (1HU+Rec). Nrf2 was 61% lower with 2HU. Tufm (-73%) and Taco1(-78%) contents were both significantly lower in 1HU. 1HU+Exshowed significantly greater Tufm (123%) and Taco1 (149%) contents when compared to CON. CONCLUSIONS: A single bout of disuse decreases the expression of canonical biogenesis markers and mitochondrial mRNA translation targets. 1HU+Ex promotes mitochondrial biogenesis more than 1HU+Rec. Multiple bouts of disuse decreases the expression of Nrf2.

Effect of computerized cognitive training with virtual spatial navigation task during bed rest immobilization and recovery on vascular function: a pilot study.

We investigated the effects of bed rest (BR) immobilization, with and without computerized cognitive training with virtual spatial navigation task (CCT), on vascular endothelium on older subjects. The effects of 14-day BR immobilization in healthy older males (n=16) of ages 53–65 years on endothelial function were studied using EndoPAT®, a noninvasive and user-independent method. From the group of 16 older men, 8 randomly received CCT during the BR, using virtual navigation tasks in a virtual environment with joystick device. In all the cases, EndoPAT assessments were done at pre- and post-BR immobilization as well as following 28 days of ambulatory recovery. The EndoPAT index increased from 1.53±0.09 (mean ± standard error of the mean) at baseline to 1.61±0.16 following immobilization (P=0.62) in the group with CCT. The EndoPAT index decreased from 2.06±0.13 (mean ± standard error of the mean) at baseline to 1.70±0.09 at the last day of BR study, day 14 (BR14) (P=0.09) in the control group. Additionally, there were no statistically significant differences between BR14 and at 28 days of follow-up (rehabilitation program) (R28). Our results show a trend of immobilization in older persons affecting the vasoconstrictory endothelial response. As the control subjects had a greater increase in EndoPAT index after R28 (+0.018) compared to subjects who had cognitive training (+0.11) (calculated from the first day of BR study), it is possible that cognitive training during BR does not improve endothelial function but rather contributes to slowing down the impairment of endothelial function. Finally, our results also show that EndoPAT may be a useful noninvasive tool to assess the vascular reactivity.

A nonparametric analysis of waiting times from a multistate model using a novel linear hazards model approach

Traditional methods for the analysis of failure time data are often employed in the analysis of waiting times of transient states from multistate models. However, such methods can exhibit bias when waiting times among model states are dependent, even when censoring is random. Furthermore, right-censoring can occur prior to entry into the transient state of interest, preventing the observation of transitions from the state and providing another potential source of bias. We introduce a nonparametric linear hazards model for waiting times from multistate models, analogous to Aalen’s linear hazards model for failure time data, where proper estimation can be carried out via reweighting, a method flexible enough to incorporate general forms of induced and other dependent censoring. We illustrate the approximate unbiasedness of the proposed regression coefficient estimators through a simulation study, while also demonstrating the bias arising from traditional Aalen’s linear hazards model estimators obtained from correlated waiting time data. Theoretical results for the parameter estimators are provided. The reweighted estimators are used in the analysis of two data sets, to identify predictors of ambulatory recovery in a data set of spinal cord injury patients receiving activity-based rehabilitation and to identify prognostic indicators for patients receiving bone marrow transplant.

Loading-associated expression of TRIM72 and caveolin-3 in antigravitational soleus muscle in mice.

Effects of mechanical loading on the expression level of tripartite motif‐containing 72 (TRIM72) and caveolin‐3 (Cav‐3) in mouse soleus muscle were investigated. Mice were subjected to (1) continuous hindlimb suspension (HS) for 2 weeks followed by 1‐week ambulation recovery or (2) functional overloading (FO) on the soleus by cutting the distal tendons of the plantaris and gastrocnemius muscles. Soleus muscle atrophy was induced by 2‐week hindlimb suspension (HS). Reloading‐associated regrowth of atrophied soleus muscle was observed by 1‐week reloading following HS. HS also depressed the expression level of insulin receptor substrate‐1 (IRS‐1) mRNA, TRIM72, Cav‐3, and phosphorylated Akt (p‐Akt)/total Akt (t‐Akt), but increased the phosphorylated level of p38 mitogen‐activated protein kinase (p‐p38MAPK) in soleus muscle. Thereafter, the expression level of MyoD mRNA, TRIM72 (mRNA, and protein), and Cav‐3 was significantly increased and recovered to the basal level during 1‐week reloading after HS. Although IRS‐1 expression was also upregulated by reloading, the expression level was significantly lower than that before HS. Significant increase in p‐Akt and phosphorylated p70 S6 kinase (p‐p70S6K) was observed by 1‐day reloading. On the other hand, 1‐week functional overloading (FO) induced soleus muscle hypertrophy. In FO‐associated hypertrophied soleus muscle, the expression level of IRS‐1 mRNA, MyoD mRNA, TRIM72 mRNA, p‐Akt, and p‐p70S6K was increased, but the expression of Cav‐3 and p‐p38MAPK was decreased. FO had no effect on the protein expression level of TRIM72. These observations suggest that the loading‐associated upregulation of TRIM72 protein in skeletal muscle may depress the regrowth of atrophied muscle via a partial suppression of IRS‐1. In addition, downregulation of Cav‐3 in skeletal muscle may depress overloading‐induced muscle hypertrophy.

Clinical and radiological results of locking plate fixation for periprosthetic femoral fractures around hip arthroplasties: a retrospective multi-center study

Background Osteosynthesis of periprosthetic femoral fractures around hip arthroplasties is challenging, and locking plate fixation has been found to be a reasonable treatment. However, there is a paucity of evidence of the extent to which patients recover their activities of daily living (ADL). The purpose of this study was to study the clinical results, particularly recovery of ADL, radiological results, and potential complications arising from the use of locking plate fixation for periprosthetic femoral fractures around hip arthroplasties.Methods We conducted a retrospective, multi-center study. Patients with periprosthetic femoral fractures around hip arthroplasties who were treated by osteosynthesis with use of locking plates and who underwent follow-up for at least 6 months postoperatively were enrolled in the study. For each patient, recovery of ADL, in terms of social and ambulatory recovery and Parker mobility score, were compared before fracture and at last follow-up. Postoperative complications were investigated. Bony union, loss of reduction, and malunion were assessed radiologically.Results Thirty-two patients were enrolled in this study. Mean follow-up was 25.1 months. For 84.4, 68.8, and 53.1 % of patients, respectively, social status, ambulation, and Parker mobility score at last follow-up were determined to be equal to that before the fracture. Bony union was observed for 30 patients within the follow-up period. Four patients had not achieved bony union 6 months postoperatively. There was no loss of reduction, malunion, or implant breakage, and no infection. For one patient each, partial pullout of the locking screws and a supracondylar fracture at the plate end were observed, and additional surgery was required.Conclusions Our results reveal that locking plate fixation provided sufficient stability for satisfactory recovery of ADL for most elderly patients with periprosthetic femoral fractures around hip arthroplasties.

Medium-term evaluation of internal fixation with pedicle screws for thoracolumbar fractures under minimally invasive endoscopy

Objective To evaluate the medium-term efficacy of internal fixation with pedicle screws under minimally invasive endoscopy for thoracolumbar fractures in comparison with traditional open pedicle screw fixation.Methods Included in this study were 96 patients who had been hospitalized for thoracolumbar fractures between January 2003 and December 2008 in our department.Of them,49 were treated with minimally invasive endoscopy (MI group) and 47 cases with traditional open pedicle screw fixation (open group).There were no significant differences between the 2 groups in general data (P ＞ O.05).The 2 groups were compared in terms of perioperative index,postoperative radiological data,visual analogue scale (VAS),Oswestry disability index (ODI) and systemic health condition.Results These patients were followed up for an average of 4.8 years.Compared with the open group,the MI group had significantly less perioperative bleeding,smaller incision,less postoperative drainage,shorter time for pain relief at the back and chest,shorter hospitalization,and shorter time for ambulatory recovery (P ＜ 0.05).There were no significant differences between the 2 groups in vertebral height,intervertebral disc height or kyphotic angle (P ＞ 0.05).The MI group scored significantly better in VAS and SF-36 than the open group postoperation (P ＜ O.05).There was no significant between-group difference in ODI (P ＞ 0.05).Conclusions In treatment of thoracolumbar fractures,minimally invasive endoscopy used for internal fixation with pedicle screws can lead to limited invasion,less pain and quick recovery.As far as the medium-term outcomes are concerned,it scores significantly better in evaluations of SF-36 score,systemic health condition,physical pain and physiological function than traditional open pedicle screw fixation. Key words: Spinal fractures; Fracture fixation, internal; Surgical procedures, minimally invasive; Endoscopy

Integrated Resistance and Aerobic Exercise Protects Fitness during Bed Rest

The current exercise countermeasures have not fully protected astronauts' preflight aerobic and muscular fitness levels during International Space Station (ISS) missions, prompting a need to optimize the exercise prescription to improve or maintain astronauts' ability to perform critical tasks and eventually extend the duration of missions. To test the hypothesis that an integrated resistance and aerobic exercise prescription performed with exercise equipment similar to that on the ISS can be tolerated and maintain cardiovascular and muscular fitness during 14 d of exposure to a model of microgravity. Subjects (n = 9) participated in 14-21 d of pre-bed rest training and familiarization, 14 d of bed rest + iRAT exercise, and 7 d of ambulatory recovery. Peak aerobic capacity (V˙O2peak), ventilatory threshold (VT), and isokinetic and leg press tests were performed before and after bed rest to evaluate cardiovascular and muscle functions. Muscle cross-sectional area (CSA) was determined before, during, and after bed rest using magnetic resonance imaging (MRI). Improvements from before to after bed rest were observed in V˙O2peak (2.8 ± 0.2 to 3.2 ± 0.2 L·min(-1)), VT (1.9 ± 0.2 to 2.1 ± 0.2 L·min(-1)), leg muscle power (1582 ± 317 to 1740 ± 359 W), and muscle CSA of the grouped vastus lateralis, vastus intermedius, and vastus medialis muscles (67.5 ± 8.4 to 68.9 ± 8.3 cm). Muscle strength and total CSA of the upper and lower legs were not different from before to after bed rest. This is the first report of exercise being completely effective for the prevention of cardiovascular and skeletal muscle deconditioning during strict bed rest using exercise equipment similar to that on the ISS. This was accomplished with high subject compliance.

Microcurrent Electrical Nerve Stimulation Facilitates Regrowth of Mouse Soleus Muscle

Microcurrent electrical nerve stimulation (MENS) has been used to facilitate recovery from skeletal muscle injury. However, the effects of MENS on unloading-associated atrophied skeletal muscle remain unclear. Effects of MENS on the regrowing process of unloading-associated atrophied skeletal muscle were investigated. Male C57BL/6J mice (10-week old) were randomly assigned to untreated normal recovery (C) and MENS-treated (M) groups. Mice of both groups are subjected to continuous hindlimb suspension (HS) for 2 weeks followed by 7 days of ambulation recovery. Mice in M group were treated with MENS for 60 min 1, 3, and 5 days following HS, respectively, under anesthesia. The intensity, the frequency, and the pulse width of MENS were set at 10 μA, 0.3 Hz, and 250 msec, respectively. Soleus muscles were dissected before and immediately after, 1, 3 and 7 days after HS. Soleus muscle wet weight and protein content were decreased by HS. The regrowth of atrophied soleus muscle in M group was faster than that in C group. Decrease in the reloading-induced necrosis of atrophied soleus was facilitated by MENS. Significant increases in phosphorylated levels of p70 S6 kinase and protein kinase B (Akt) in M group were observed, compared with C group. These observations are consistent with that MENS facilitated regrowth of atrophied soleus muscle. MENS may be a potential extracellular stimulus to activate the intracellular signals involved in protein synthesis.