OBJECTIVE To investigate the effects and mechanisms of Lycium ruthenicum Murr. in improving sleep. METHODS Network pharmacology was employed to identify the active components of L. ruthenicum and their associated disease targets， followed by enrichment analysis. A caffeine‑induced zebrafish model of sleep deprivation was established ， and the zebrafish were treated with L. ruthenicum Murr. extract （LRME） at concentrations of 0.1， 0.2 and 0.4 mg/mL， respectively； 24 h later， behavioral changes of zebrafish and pathological alterations in brain neurons were subsequently observed. The levels of inflammatory factors [interleukin-6 （IL-6）， IL-1β， IL-10， tumor necrosis factor-α （TNF-α）]， oxidative stress markers [superoxide dismutase （SOD）， malondialdehyde （MDA）， glutathione peroxidase （GSH-Px）， catalase （CAT）]， and neurotransmitters [5- hydroxytryptamine （5-HT）， γ-aminobutyric acid （GABA）， glutamic acid （Glu）， dopamine （DA）， and norepinephrine （NE）] were measured. The protein expression levels of protein kinase B1 （AKT1）， phosphorylated AKT1 （p-AKT1）， epidermal growth factor receptor （EGFR）， B-cell lymphoma 2 （Bcl-2）， sarcoma proto-oncogene，non-receptor tyrosine kinase （SRC）， and heat shock protein 90α family class A member 1 （HSP90AA1） in the zebrafish were also determined. RESULTS A total of 12 active components and 176 intersecting disease targets were identified through network pharmacology analysis. Among these， apigenin， naringenin and others were recognized as core active compounds， while AKT1， EGFR and others served as key targets； EGFR tyrosine kinase inhibitor resistance signaling pathway was identified as the critical pathway. The sleep improvement rates in zebrafish of LRME low-， medium-， and high-dose groups were 54.60%， 69.03% and 77.97%， 开发。E-mail：hjp_yft@163.com respectively， while the inhibition ratios of locomotor distance were 0.57， 0.83 and 0.95， respectively. Compared with the model group， the number of resting counts， resting time and resting distance were significantly increased/extended in LRME medium- and high-dose groups （P＜0.05）. Neuronal damage in the brain was alleviated. Additionally， the levels of IL-6， IL-1β， TNF-α， MDA， Glu， DA and NE， as well as the protein expression levels of AKT1， p-AKT1， EGFR， SRC and HSP90AA1， were markedly reduced （P＜0.05）， while the levels of IL-10， SOD， GSH-Px， CAT， 5-HT and GABA， as well as Bcl-2 protein expression， were significantly elevated （P＜0.05）. CONCLUSIONS L. ruthenicum Murr. demonstrates sleep-improving effects， and its specific mechanism may be related to the regulation of inflammatory responses， oxidative stress， neurotransmitter balance， and the EGFR tyrosine kinase inhibitor resistance signaling pathway.

ObjectiveTo investigate the mechanisms by which Bushen Tongluo Jiangzhuo prescription improves renal fibrosis in rats with chronic kidney disease （CKD） through the phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt）/mammalian target of rapamycin （mTOR） signaling pathway. MethodsSeventy specific pathogen-free （SPF） Sprague-Dawley （SD） rats were randomly divided into a control group （n=15） and a modeling group （n=55）. Rats in the modeling group were administered a 2.5% adenine suspension at a dose of 200 mg·kg^-1·d^-1 by gavage for 4 weeks to establish a CKD model. Successfully modeled rats were randomly divided into a model group， an irbesartan group （20.25 mg·kg^-1·d^-1）， and Bushen Tongluo Jiangzhuo prescription low-， medium-， and high-dose groups （5.82， 11.64， and 23.28 g·kg^-1·d^-1， respectively）， with 10 rats in each group. Each group was administered an equal volume of physiological saline， the corresponding concentration of irbesartan， or Bushen Tongluo Jiangzhuo prescription by gavage for 12 weeks. Body weight and renal function indices were dynamically monitored. Serum creatinine （SCr）， blood urea nitrogen （BUN）， urine albumin-to-creatinine ratio （ACR）， 24-hour urinary total protein （24 hUTP）， aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， interleukin-1β （IL-1β）， interleukin-6 （IL-6）， and tumor necrosis factor-α （TNF-α） levels were measured using an automatic biochemical analyzer. Renal histopathological changes were observed by hematoxylin-eosin （HE） and Masson staining. Immunohistochemistry （IHC） was used to detect the expression of PI3K， Akt， phosphorylated Akt （p-Akt）， and mTOR in renal tissues. Western blot was performed to assess the protein expression of PI3K， p-Akt， Akt， phosphorylated mTOR （p-mTOR）， and mTOR in renal tissues. Real-time quantitative polymerase chain reaction （Real-time PCR） was used to determine the mRNA expression levels of PI3K， Akt， and mTOR in renal tissues. ResultsCompared with the model group， rats in the irbesartan group and the low-， medium-， and high-dose Bushen Tongluo Jiangzhuo prescription groups showed significantly decreased levels of SCr， BUN， ACR， 24 hUTP， IL-1β， IL-6， and TNF-α （P<0.01）. AST levels were significantly increased （P<0.01）， while no significant difference was observed in ALT levels. Histopathological examination revealed that， compared with the model group， renal tubular epithelial cell edema and necrosis and Bowman's capsule dilation were alleviated， inflammatory cell infiltration was reduced， and interstitial and glomerular fibrosis was markedly improved in all treatment groups， with the most pronounced effect observed in the high-dose Bushen Tongluo Jiangzhuo prescription group. Real-time PCR results showed that mRNA expression levels of PI3K， Akt， and mTOR were significantly downregulated in the high-dose group （P<0.01）. IHC results demonstrated that PI3K and p-Akt expression levels in renal tissues were significantly decreased in the high-dose group （P<0.01）. Western blot analysis further confirmed that the expression levels of PI3K， p-Akt/Akt， and p-mTOR/mTOR were significantly reduced in the high-dose group （P<0.01）. ConclusionBushen Tongluo Jiangzhuo prescription improves renal function indices in CKD rats， reduces collagen deposition in renal tissues， and decreases serum inflammatory factor levels. Its protective effect on renal function may be achieved by activating autophagy through downregulation of the PI3K/Akt/mTOR signaling pathway， thereby alleviating renal fibrosis.

BACKGROUND:The quadriceps strength of patients with osteoporosis and sarcopenia is significantly reduced,which can further reduce the function of the knee joint,affect the function of the lower limbs and even lead to a decrease in whole-body coordination.It is speculated that a reasonable quadriceps training program and personalized guidance are beneficial to the recovery of knee joint function in patients with osteoporosis and sarcopenia.OBJECTIVE:To observe the effect of short-term moderate-intensity resistance rehabilitation training on the mass and function of the quadriceps and knee joint function in patients with osteoporosis and sarcopenia.METHODS:Using the integrated physical examination and rehabilitation model,375 patients with osteoporosis and sarcopenia were screened at the Health Management Center of Shanghai Public Health Clinical Center.They underwent 12 weeks of combined/comprehensive exercise rehabilitation based on resistance exercise,including quadriceps resistance isotonic and isometric contraction training twice a week(3-5 sets each time,10-15 minutes per set)and aerobic exercise/balance exercise two or three times a week(30 minutes each time).Assessments and data collection were performed before rehabilitation training,12 weeks after rehabilitation training,and at follow-up 12 weeks after stopping rehabilitation training,mainly including knee joint range of motion and proprioception,quadriceps muscle strength,and cross-sectional area(magnetic resonance imaging results),pain,knee joint function(Hospital for Special Surgery score)and walking function("up-and-go"time and 6 m pace test results)as well as the patient's psychological status assessment.RESULTS AND CONCLUSION:All 375 patients completed 12 weeks of rehabilitation training and 12 weeks of follow-up without any adverse events.(1)Compared with before training,the patients' gait speed and knee range of motion increased significantly after 12 weeks of rehabilitation training(P＜0.01),the time of"stand-to-walk"decreased(P＜0.01),and the proprioception of the knee joint and the strength of the quadriceps femoris were significantly improved(P＜0.01);and at the follow-up visit 12 weeks after stopping training,the above indicators and functions of the patients were well maintained(P＞0.05).(2)Magnetic resonance imaging results showed that the effective cross-sectional area of the quadriceps femoris did not improve significantly after 12 weeks of rehabilitation training(P＞0.05);but the Hospital for Special Surgery score of knee joint function increased significantly(P＜0.01),and the visual analog pain scale score decreased significantly(P＜0.01),suggesting that this may be related to the improvement of quadriceps femoris quality by resistance rehabilitation training.(3)The results of the Hospital Anxiety and Depression Scale score showed that the anxiety and depression scores of the patients continued to decrease,both at 12 weeks of rehabilitation training and at 12 weeks after stopping training(P＜0.01).It is suggested that resistance rehabilitation training of the quadriceps can help patients with osteoporosis and sarcopenia to restore quadriceps muscle strength,increase range of motion,improve proprioception and joint stability,thereby enhancing knee joint function,reducing pain,improving depression and anxiety,and to a certain extent promoting the coordinated recovery of the musculoskeletal system.

BACKGROUND:The quadriceps strength of patients with osteoporosis and sarcopenia is significantly reduced,which can further reduce the function of the knee joint,affect the function of the lower limbs and even lead to a decrease in whole-body coordination.It is speculated that a reasonable quadriceps training program and personalized guidance are beneficial to the recovery of knee joint function in patients with osteoporosis and sarcopenia.OBJECTIVE:To observe the effect of short-term moderate-intensity resistance rehabilitation training on the mass and function of the quadriceps and knee joint function in patients with osteoporosis and sarcopenia.METHODS:Using the integrated physical examination and rehabilitation model,375 patients with osteoporosis and sarcopenia were screened at the Health Management Center of Shanghai Public Health Clinical Center.They underwent 12 weeks of combined/comprehensive exercise rehabilitation based on resistance exercise,including quadriceps resistance isotonic and isometric contraction training twice a week(3-5 sets each time,10-15 minutes per set)and aerobic exercise/balance exercise two or three times a week(30 minutes each time).Assessments and data collection were performed before rehabilitation training,12 weeks after rehabilitation training,and at follow-up 12 weeks after stopping rehabilitation training,mainly including knee joint range of motion and proprioception,quadriceps muscle strength,and cross-sectional area(magnetic resonance imaging results),pain,knee joint function(Hospital for Special Surgery score)and walking function("up-and-go"time and 6 m pace test results)as well as the patient's psychological status assessment.RESULTS AND CONCLUSION:All 375 patients completed 12 weeks of rehabilitation training and 12 weeks of follow-up without any adverse events.(1)Compared with before training,the patients' gait speed and knee range of motion increased significantly after 12 weeks of rehabilitation training(P＜0.01),the time of"stand-to-walk"decreased(P＜0.01),and the proprioception of the knee joint and the strength of the quadriceps femoris were significantly improved(P＜0.01);and at the follow-up visit 12 weeks after stopping training,the above indicators and functions of the patients were well maintained(P＞0.05).(2)Magnetic resonance imaging results showed that the effective cross-sectional area of the quadriceps femoris did not improve significantly after 12 weeks of rehabilitation training(P＞0.05);but the Hospital for Special Surgery score of knee joint function increased significantly(P＜0.01),and the visual analog pain scale score decreased significantly(P＜0.01),suggesting that this may be related to the improvement of quadriceps femoris quality by resistance rehabilitation training.(3)The results of the Hospital Anxiety and Depression Scale score showed that the anxiety and depression scores of the patients continued to decrease,both at 12 weeks of rehabilitation training and at 12 weeks after stopping training(P＜0.01).It is suggested that resistance rehabilitation training of the quadriceps can help patients with osteoporosis and sarcopenia to restore quadriceps muscle strength,increase range of motion,improve proprioception and joint stability,thereby enhancing knee joint function,reducing pain,improving depression and anxiety,and to a certain extent promoting the coordinated recovery of the musculoskeletal system.

Electroencephalogram (EEG) is a non-invasive, high temporal-resolution technique for monitoring brain activity. However, affected by the volume conduction effect, EEG has a low spatial resolution and is difficult to locate brain neuronal activity precisely. The surface Laplacian (SL) technique obtains the Laplacian EEG (LEEG) by estimating the second-order spatial derivative of the scalp potential. LEEG can reflect the radial current activity under the scalp, with positive values indicating current flow from the brain to the scalp (“source”) and negative values indicating current flow from the scalp to the brain (“sink”). It attenuates signals from volume conduction, effectively improving the spatial resolution of EEG, and is expected to contribute to breakthroughs in neural engineering. This paper provides a systematic overview of the principles and development of SL technology. Currently, there are two implementation paths for SL technology: current source density algorithms (CSD) and concentric ring electrodes (CRE). CSD performs the Laplace transform of the EEG signals acquired by conventional disc electrodes to indirectly estimate the LEEG. It can be mainly classified into local methods, global methods, and realistic Laplacian methods. The global method is the most commonly used approach in CSD, which can achieve more accurate estimation compared with the local method, and it does not require additional imaging equipment compared with the realistic Laplacian method. CRE employs new concentric ring electrodes instead of the traditional disc electrodes, and measures the LEEG directly by differential acquisition of the multi-ring signals. Depending on the structure, it can be divided into bipolar CRE, quasi-bipolar CRE, tripolar CRE, and multi-pole CRE. The tripolar CRE is widely used due to its optimal detection performance. While ensuring the quality of signal acquisition, the complexity of its preamplifier is relatively acceptable. Here, this paper introduces the study of the SL technique in resting rhythms, visual-related potentials, movement-related potentials, and sensorimotor rhythms. These studies demonstrate that SL technology can improve signal quality and enhance signal characteristics, confirming its potential applications in neuroscientific research, disease diagnosis, visual pathway detection, and brain-computer interfaces. CSD is frequently utilized in applications such as neuroscientific research and disease detection, where high-precision estimation of LEEG is required. And CRE tends to be used in brain-computer interfaces, that have stringent requirements for real-time data processing. Finally, this paper summarizes the strengths and weaknesses of SL technology and envisages its future development. SL technology boasts advantages such as reference independence, high spatial resolution, high temporal resolution, enhanced source connectivity analysis, and noise suppression. However, it also has shortcomings that can be further improved. Theoretically, simulation experiments should be conducted to investigate the theoretical characteristics of SL technology. For CSD methods, the algorithm needs to be optimized to improve the precision of LEEG estimation, reduce dependence on the number of channels, and decrease computational complexity and time consumption. For CRE methods, the electrodes need to be designed with appropriate structures and sizes, and the low-noise, high common-mode rejection ratio preamplifier should be developed. We hope that this paper can promote the in-depth research and wide application of SL technology.

ObjectiveThe study explores the influence of voluntary wheel running on the behavioral abnormalities and the activation state of the hypothalamic-pituitary-adrenal (HPA) axis in autism spectrum disorder (ASD) rats through gut microbiota. MethodsSD female rats were selected and administered either400 mg/kg of valproic acid (VPA) solution or an equivalent volume of saline via intraperitoneal injection on day 12.5 of pregnancy. The resulting offspring were divided into 2 groups: the ASD model group (PASD, n=35) and the normal control group (PCON, n=16). Behavioral assessments, including the three-chamber social test, open field test, and Morris water maze, were conducted on postnatal day 23. After behavioral testing, 8 rats from each group (PCON, PASD) were randomly selected for serum analysis using enzyme-linked immunosorbent assay (ELISA) to measure corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and corticosterone (CORT) concentration, to evaluate the functional state of the HPA axis in rats. On postnatal day 28, the remaining 8 rats in the PCON group were designated as the control group (CON, n=8), and the remaining 27 rats in the PASD group were randomly divided into 4 groups: ASD non-intervention group (ASD, n=6), ASD exercise group (ASDE, n=8), ASD fecal microbiota transplantation group (FMT, n=8), and ASD sham fecal microbiota transplantation group (sFMT, n=5). The rats in the ASD group and the CON group were kept under standard conditions, while the rats in the ASDE group performed 6 weeks of voluntary wheel running intervention starting on postnatal day 28. The rats in the FMT group were gavaged daily from postnatal day 42 with 1 ml/100 g fresh fecal suspension from ASDE rats which had undergone exercise for 2 weeks, 5 d per week, continuing for 4 weeks. The sFMT group received an equivalent volume of saline. After the interventions were completed, behavioral assessments and HPA axis markers were measured for all groups. ResultsBefore the intervention, the ASD model group exhibited significantly reduced social ability, social novelty preference, spontaneous activity, and exploratory interest, as well as impaired spatial learning, memory, and navigation abilities compared to the normal control group (P<0.05). Serum concentration of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and corticosterone (CORT) in the PASD group were significantly higher than those in the PCON group (P<0.05). Following 6 weeks of voluntary wheel running, the ASDE group showed significant improvements in social ability, social novelty preference, spontaneous activity, exploratory interest, spatial learning, memory, and navigation skills compared to the ASD group (P<0.05), with a significant decrease in serum CORT concentration (P<0.05), and a downward trend in CRH and ACTH concentration. After 4 weeks of fecal microbiota transplantation in the exercise group, the FMT group showed marked improvements in social ability, social novelty preference, spontaneous activity, exploratory interest, as well as spatial learning, memory, and navigation abilities compared to both the ASD and sFMT groups (P<0.05). In addition, serum ACTH and CORT concentration were significantly reduced (P<0.05), and CRH concentration also showed a decreasing trend. ConclusionExercise may improve ASD-related behaviors by suppressing the activation of the HPA axis, with the gut microbiota likely playing a crucial role in this process.

Objective To explore the influencing factors of coronary artery lesion severity in patients with acute coronary syndrome (ACS). Methods Clinical data of ACS patients admitted to Zhongshan Hospital, Fudan University from December 2017 to December 2019 were consecutively collected. The modified Gensini score was used to assess the severity of coronary artery lesions. Univariate and multivariate linear regression analyses were performed to identify independent factors associated with coronary artery lesion severity. Results A total of 1 689 ACS patients were included, with an average age of (64.04±11.45) years; 1 353 (80.11%) were male, and the mean modified Gensini score was (8.12±4.03). Multivariate linear regression analysis revealed that sex (β＝0.97, P＝0.001), age (β＝0.03, P＝0.021), estimated glomerular filtration rate (eGFR; β＝－0.03, P＜0.001), low-density lipoprotein cholesterol (LDL-C; β＝0.58, P＜0.001), apolipoprotein A1 (Apo A1; β＝－1.28, P＝0.012), lipoprotein(a) [Lp(a); β＝0.001, P＝0.033], and glycated hemoglobin A_1C (HbA_1C; β＝0.45, P＜0.001) were independent influencing factors of the modified Gensini score. Conclusions Metabolic indicators, including Apo A1, LDL-C, HbA_1C, and Lp(a), may serve as risk factors for coronary artery lesion severity in ACS patients, with Apo A1 demonstrating the strongest impact.

Objective To analyze the clinical efficacy of valve surgeries for infective endocarditis and the affecting factors, and compare the early- and long-term postoperative outcomes of different surgery approaches. Methods The patients with infective endocarditis who underwent valve replacement/valvuloplasty in our hospital from 2010 to 2022 were retrospectively collected. The clinical data of the patients were analyzed. Results A total of 343 patients were enrolled, including 197 patients with mechanical valve replacement, 62 patients with bioprosthetic valve replacement, and 84 patients with valvuloplasty. There were 238 males and 105 females with an average age of (44.2±14.8) years. Single-valve endocarditis was present in 200 (58.3%) patients, and multivalve involvement was present in 143 (41.7%) patients. Sixty (17.5%) patients had suffered thrombosis before surgery, including cerebral embolisms in 32 patients. The mean follow-up time was (60.6±43.8) months. Early mortality within one month after the surgery occurred in 17 (5.0%) patients, while later mortality occurred in 19 (5.5%) patients. Eight (2.3%) patients underwent postoperative dialysis, 13 (3.8%) patients suffered postoperative stroke, 6 patients underwent reoperation, and 3 patients suffered recurrence of infective endocarditis. Smoking (P=0.002), preoperative embolisms (P=0.001), duration of surgery (P=0.001), and postoperative dialysis (P=0.001) were risk factors for early mortality, and left ventricular ejection fraction ≥60% (P=0.022) was protective factor for early mortality. New York Heart Association classification Ⅲ-Ⅳ (P=0.010) and ≥3 valve procedures (P=0.028) were risk factors for late mortality. The rate of composite endpoint events was significantly lower in the valvuloplasty group than that in the valve replacement group. Conclusion For patients with infective endocarditis, smoking and preoperative embolisms are associated with high postoperative mortality, multiple-valve surgery is associated with a poorer prognosis, and valvuloplasty has advantages over valve replacement and should be attempted in the surgical management of patients with infective endocarditis.

OBJECTIVE: Based on the PTEN-induced hypothetical kinase 1 (PINK1)/Parkin pathway, the effect of acupuncture pretreatment on the expression of mitochondrial autophagy-related proteins in gastrocnemius muscle tissue of rats with exercise-induced muscle damage (EIMD) was observed, and the underlying mechanism of acupuncture pretreatment for the prevention and treatment of EIMD was explored. METHODS: Of 88 SD male rats, aged 6 weeks, 8 rats were randomly selected as a blank group, and the remaining 80 rats were randomized into a model group and an acupuncture pretreatment group, with 40 rats in each group. Either the model group or the acupuncture pretreatment group was subdivided randomly into 5 subgroups with 8 rats in each one according to the time points of sample collection, 0 h, 12 h, 24 h, 48 h and 72 h after modeling. An intermittent downhill running centrifugal exercise was carried out on an animal experimental treadmill to establish the EIMD model in the model group and the acupuncture pretreatment group. The rats in the acupuncture pretreatment group received acupuncture at "Guanyuan" (CV6) and bilateral "Zusanli" (ST36), once a day for 20 min each time, for 7 consecutive days before EIMD model preparation. Transmission electron microscopy was used to observe the ultrastructure of gastrocnemius muscle tissue in each group. The contents of malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) in serum were detected by ELISA. Western blot was used to detect the protein expression of PINK1, Parkin, sequestosome 1 (p62) and microtubule-associated protein light chain 3B (LC3B) in rat gastrocnemius muscle tissue. Real-time PCR was adopted to detect the mRNA expression of PINK1, Parkin, p62 and LC3B in rat gastrocnemius muscle tissue. RESULTS: Compared with the blank group, the mitochondria of gastrocnemius muscles showed obvious swelling in the 0 h, 12 h, 24 h, and 48 h model subgroups , autophagosomes were formed in the 12 h and 24 h model subgroups, and the mitochondrial morphology returned to normal gradually in the 72 h model subgroup. The serum MDA contents of rats in 5 model subgroups increased (P<0.01, P<0.05). The contents of SOD and CAT in the subgroups of 0 h, 12 h, 24 h and 48 h decreased (P<0.05, P<0.01). The protein and mRNA expression levels of PINK1, Parkin and LC3B in gastrocnemius muscle tissue of rats in 0 h, 12 h and 24 h subgroups were elevated (P<0.01); and the protein and mRNA expression levels of p62 in the 0 h, 12 h, 24 h and 48 h subgroups were reduced (P<0.01, P<0.05). Compared with the model subgroup at the same time point, the myofibril damage and the degree of mitochondrial swelling were mild in each acupuncture pretreatment subgroup, and the numbers of autophagosomes were fewer. The contents of MDA in the acupuncture pretreatment subgroups decreased at 0 h, 12 h, 24 h, and 48 h (P<0.05, P<0.01). The contents of SOD and CAT in the 12 h acupuncture pretreatment subgroup increased (P<0.05, P<0.01). The protein and mRNA expression levels of PINK1 and Parkin in the 0 h, 12 h, and 24 h acupuncture pretreatment subgroups decreased (P<0.01, P<0.05). The protein and mRNA expression levels of LC3B in the 12 h acupuncture pretreatment subgroup decreased (P<0.01), and that of p62 in the 0 h and 24 h acupuncture pretreatment subgroups increased (P<0.01, P<0.05). CONCLUSION The intermittent downhill running centrifugal exercise induces the excessive mitochondrial autophagy. Acupuncture pretreatment may attenuate EIMD, and the underlying mechanism is related to the regulation of PINK1/Parkin signaling pathway expression, reducing oxidative stress damage in skeletal muscle cells, and inhibiting mitochondrial autophagy overactivation.
Animals ; Ubiquitin-Protein Ligases/genetics* ; Male ; Rats ; Acupuncture Therapy ; Protein Kinases/genetics* ; Rats, Sprague-Dawley ; Mitophagy ; Humans ; Muscle, Skeletal/metabolism* ; Physical Conditioning, Animal ; Muscular Diseases/physiopathology* ; Signal Transduction