Changes In Muscle Research Articles

Morphological changes of the semitendinosus muscle among ambulant children with spastic cerebral palsy

Morphological changes of the semitendinosus muscle among ambulant children with spastic cerebral palsy

Analysis of Electrooculogram in Detecting Eye Movements Associated with Brain Injury

Electrooculogram (EOG) has been a valuable clinical neurophysiology tool in the past five decades of the twentieth century. It facilitated understanding more about eye movement, which is clinically useful in identifying the neural substrate disrupted due to brain injuries. This is vital since accurate measurement of neural injuries has a direct bearing on a patient’s life. A number of neurological investigations, including neurological assessment and diagnosis, are done based on measuring eye movements. This essay focuses on using EOG technology and its benefits in identifying limitations of using physiological indices in individuals because of measurable ocular pathophysiological parameters. In the current essay, the major objective will be to discuss the EOG features, the EOG record in healthy individuals, and the relationship of EOG recordings to affected individuals following a neurological event. The eye-integrated EOG recorded from the front part of the face measures eye position change and shows an exponential decay of voltage due to its design, eye physiology, and the removal of corneal function slowly from the corneal electrode. This makes it the best choice to provide an eye position record with high accuracy that can be made available easily for clinicians. The rapid recordings obtained using transcranial electromagnetic stimulation could demonstrate that EOG has the potential to provide high pre-surgical planning utilities for brain tumor removal. This technology is also best for identifying physiological variability within an individual; the same concept can be extended to study brain injuries that trigger physiological changes in eye muscles. In effect, it potentially becomes a tool for personalized care wherein severity estimation for brain injuries would be based on measuring ocular function rather than the nature of the injury. Given its clinical potential, the present essay will review EOG technologies to assess eye pixel movement, its potential for clinical evaluation, physiological basis, and the research evidence regarding changes in EOG in affected individuals with brain injury. In this essay, the long-lasting and short-lasting EOG changes are presented as case studies of individuals diagnosed with PTA, hence demonstrating its clinical utility.

Abstract P126: Exercise-Induced Changes in Skeletal Muscle of Patients with Chronic Kidney Disease on Maintenance Hemodialysis

Background: Chronic kidney disease (CKD) patients on maintenance hemodialysis (MHD) often experience sarcopenia and functional decline. The impact of exercise and inactivity on sarcopenia in CKD is poorly understood. We aimed to identify exercise-responsive genes that are differentially expressed between controls and patients on MHD. We also aim to investigate the changes in gene expression in skeletal muscle following a resistance exercise program in patients on MHD. Methods: In a cross-sectional study, we performed RNA sequencing analysis in skeletal muscle biopsies from two groups (matched for age, gender, body mass index, and history of diabetes): controls (n=13) and patients on maintenance hemodialysis (MHD, n=10). In a separate cohort, we conducted a 12-week intradialytic resistance training in seven patients on MHD. Skeletal muscle biopsies were collected pre- and post-intervention to assess the acute (before and after a single bout of exercise) and chronic (after 12 weeks) effects of exercise. Total RNA was extracted and used to construct libraries for RNA sequencing using the Illumina NovaSeq 6000 system. Differentially expressed genes (DEGs) were identified based on a false discovery rate (FDR) of less than 0.05 and a fold change greater than 1.5. Exercise and inactivity-responsive genes in non-CKD populations identified in the MetaMEx (www.metamex.eu) were used as reference. Results: We found significant DEGs between the control and MHD that were affected by exercise or inactivity according to MetaMEx. These genes and fold changes between control and MHD groups are depicted in Table 1. In the exercise intervention cohort, we observed no significant differences in the expression of these genes either acutely (Figure 1A) or 12 weeks after the exercise intervention (Figure 1B). Conclusion: We found many DEGs related to exercise and inactivity between patients on MHD and controls; however, resistance training does not significantly alter skeletal muscle gene expression. Future studies should explore alternative exercise interventions, such as HIIT exercise, aerobic training, combined aerobic and resistance training, or longer duration programs, to determine if these approaches can effectively modulate gene expression and improve sarcopenia and frailty in this population.

Developmental and physiological impacts of pathogenic human huntingtin protein in the nervous system.

Huntington's Disease (HD) is a neurodegenerative disorder, part of the nine identified inherited polyglutamine (polyQ) diseases. Most commonly, HD pathophysiology manifests in middle-aged adults with symptoms including progressive loss of motor control, cognitive decline, and psychiatric disturbances. Associated with the pathophysiology of HD is the formation of insoluble fragments of the huntingtin protein (htt) that tend to aggregate in the nucleus and cytoplasm of neurons. To track both the intracellular progression of the aggregation phenotype as well as the physiological deficits associated with mutant htt, two constructs of human HTT were expressed with varying polyQ lengths, non-pathogenic-htt (Q15, NP-htt) and pathogenic-htt (Q138, P-htt), with an N-terminal RFP tag for in vivo visualization. P-htt aggregates accumulate in the ventral nerve cord cell bodies as early as 24 hours post hatching and significant aggregates form in the segmental nerve branches at 48 hours post hatching. Organelle trafficking up-and downstream of aggregates formed in motor neurons showed severe deficits in trafficking dynamics. To explore putative downstream deficits of htt aggregation, ultrastructural changes of presynaptic motor neurons and muscles were assessed, but no significant effects were observed. However, the force and kinetics of muscle contractions were severely affected in P-htt animals, reminiscent of human chorea. Reduced muscle force production translated to altered locomotory behavior. A novel HD aggregation model was established to track htt aggregation throughout adulthood in the wing, showing similar aggregation patterns with larvae. Expressing P-htt in the adult nervous system resulted in significantly reduced lifespan, which could be partially rescued by feeding flies the mTOR inhibitor rapamycin. These findings advance our understanding of htt aggregate progression as well the downstream physiological impacts on the nervous system and peripheral tissues.

The Significance of Longitudinal Psoas Muscle Loss in Predicting the Maintenance Efficacy of Durvalumab Treatment Following Concurrent Chemoradiotherapy in Patients with Non-Small Cell Lung Cancer: A Retrospective Study.

Sarcopenia assessed at a single time point is associated with the efficacy of immunotherapy, and we hypothesized that longitudinal changes in muscle mass may also be important. This retrospective study included patients with non-small cell lung cancer (NSCLC) who received durvalumab treatment after concurrent chemoradiotherapy (CCRT) between January 2017 and April 2023. Muscle loss and sarcopenia were assessed based on the lumbar skeletal muscle area. Patients with a decrease in muscle area of 10% or more during CCRT were categorized into the muscle loss group, while those with a decrease of less than 10% were categorized into the muscle maintenance group. We evaluated the relationship between muscle changes during CCRT and the efficacy of durvalumab treatment. Among the 98 patients, the muscle maintenance group had a significantly longer PFS of durvalumab treatment compared to the muscle loss group (29.2 months [95% confidence interval (CI): 17.2-not reached] versus 11.3 months [95% CI: 7.6-22.3]; p = 0.008). The multivariable analysis confirmed that muscle change was a significant predictor of a superior PFS (HR: 0.47 [95% CI: 0.25-0.90]; the p-value was less than 0.05). In contrast, the OS between the groups did not differ significantly (not reached [95% CI: 21.8 months-not reached] and 36.6 months [95% CI: 26.9-not reached]; p = 0.49). Longitudinal muscle changes during CCRT are a predictor of durvalumab's efficacy in patients with NSCLC after CCRT.

Changes of masseter muscle after mandible distraction osteogenesis in patients with Hemifacial microsomia: a retrospective study.

Mandible distraction osteogenesis (MDO) is widely used to reconstruct the mandible in patients with mild Hemifacial microsomia (HFM). However, the masseter's response to mandible distraction remains unclear. In this study, we analyze the effect of the surgical intervention on masseter muscle by a retrospective analysis. The procedure consisted of a five-day latent period, a three-week distraction period, and a six-month consolidation period. CT data were manually segmented and measured with Mimics software before surgery, within 3 months, and more than 1 year postoperatively. Masseter volume, masseter length, masseter width, and mandible ramus height were measured and analyzed using paired t-test, Pearson, and Spearman correlation analysis. We included 21 patients with HFM who underwent mandible distraction osteogenesis from 2015 to 2020. The masseter volume on the affected side increased immediately after surgery from (6,505.33 ± 3,671.95) mm3 to (10,194.60 ± 5638.79) mm3, but decreased to (8,148.38 ± 3,472.57) mm3 at the second follow-up correlated to mandible ramus height (r = 0.395, P = 0.038). A similar trend was observed in changes in masseter length. Symmetry and width of masseter muscle had no longitudinal statistical significance. Masseter muscle involvement benefits from MDO in the short term. To achieve long-term efficacy, more attention should be paid to muscle reconstruction.

Changes in 3-Dimensional Measurements of Masseter Muscle After Orthognathic Surgery in Patients with Facial Asymmetry.

The aim of this study was to quantitatively evaluate morphological and volumetric changes in the masseter muscle using 3-dimensional analysis of facial asymmetry patients and to identify factors influencing these changes before and after orthognathic surgery. [Reviewer1 (2)]A single-center retrospective cohort study was conducted on twenty-two patients with deviation of the chin > 4mm. Masseter muscle volume and morphology were measured at different periods during long-term follow-up (mean 15 ± 3.2months). Factors related to changes in masseter muscle cross-sectional area and volume analyzed were also analyzed. [Reviewer1 (2) and (9)]The volume and cross-sectional area of the masseter muscle on the non-deviated side reduced by 13.5% (P < 0.05) and 16.4% (P < 0.05), respectively, after orthognathic surgery. The length of the masseter muscle increased by 13.9% on the deviated side (P < .05) but decreased by 11.7% on the non-deviated side (P < 0.05). The width decreased on the deviated side from T1 to T2 (13.51 ± 2.09mm vs. 12.04 ± 1.39mm), but the non-deviated side showed an opposite tendency (10.81 ± 1.31mm vs. 12.69 ± 2.37mm). The difference in masseter muscle length and width between the two sides significantly reduced after surgery (P < 0.05). There was a noticeable decrease in the asymmetry in the muscle in proportion to the degree of the occlusal plane angle. Masseter muscle asymmetry exists in patients with facial asymmetry, but it could be improved with maxilla-mandible correction. Atrophy of the masseter muscle after orthognathic surgery was greater in patients with a large inclined occlusal plane angle due to improved dental compensation. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Significant age-related differences between lower leg muscles of older and younger female subjects detected by ultrashort echo time magnetization transfer modeling.

Magnetization transfer (MT) magnetic resonance imaging (MRI) can be used to estimate the fraction of water and macromolecular proton pools in tissues. MT modeling paired with ultrashort echo time acquisition (UTE-MT modeling) has been proposed to improve the evaluation of the myotendinous junction and fibrosis in muscle tissues, which the latter increases with aging. This study aimed to determine if the UTE-MT modeling technique is sensitive to age-related changes in the skeletal muscles of the lower leg. Institutional review board approval was obtained, and all recruited subjects provided written informed consent. The legs of 31 healthy younger (28.1±6.1years old, BMI = 22.3±3.5) and 20 older (74.7±5.5years old, BMI = 26.7±5.9) female subjects were imaged using UTE sequences on a 3T MRI scanner. MT ratio (MTR), macromolecular fraction (MMF), macromolecular T2 (T2-MM), and water T2 (T2-W) were calculated using UTE-MT modeling for the anterior tibialis (ATM), posterior tibialis (PTM), soleus (SM), and combined lateral muscles. Results were compared between groups using the Wilcoxon rank sum test. Three independent observers selected regions of interest (ROIs) and processed UTE-MRI images separately, and the intraclass correlation coefficient (ICC) was calculated for a reproducibility study. Significantly lower mean MTR and MMF values were present in the older compared with the younger group in all studied lower leg muscles. T2-MM showed significantly lower values in the older group only for PTM and SM muscles. In contrast, T2-W showed significantly higher values in the older group. The age-related differences were more pronounced for MMF (-17 to -19%) and T2-W (+20 to 47%) measurements in all muscle groups compared with other investigated MR measures. ICCs were higher than 0.93, indicating excellent consistency between the ROI selection and MRI measurements of independent readers. As demonstrated by significant differences between younger and older groups, this research emphasizes the potential of UTE-MT MRI techniques in evaluating age-related skeletal muscle changes.

Pre-operative gluteus medius tendon degeneration and its impact on strength and functional ability one year after total hip replacement

Objective Hip osteoarthritis is a common cause of disability and surgery is often unavoidable. Patient satisfaction is high and functional ability improves after surgery. However, residual impairment and pain are common. Degenerative changes in tendons and muscles are probable causes. The aim of this study is to investigate gluteus medius (GMED) tendon degeneration in relation to muscle strength, physical function and walking distance before and one year after total hip replacement. Material and methods In total, 18 patients were examined pre- and post-operatively, of whom 15 were available in the final analysis. Muscle strength, physical function and walking distance were assessed. Tendon biopsies were assessed microscopically, and the total degeneration score (TDS) was calculated. Results A correlation between the TDS and muscle strength was found for the hamstrings, GMED and quadriceps pre- or post-operatively. No correlations were found between the TDS and functional ability. Functional ability and muscle strength improved significantly after surgery. Conclusion Our results indicate a correlation between tendon degeneration and the muscle strength of the hip and knee in patients with hip OA and one year after THR. To minimise post-operative residual discomfort, rehabilitation programs should probably be modified over time to match the pre- and post-operative needs. Further studies are needed. This study was registered at https://www.researchweb.org/is/vgr/project/279039 (in Swedish).

Enhanced therapeutic efficacy of SERCA2a gene-modified adipose-derived mesenchymal stem cell exosomes in doxorubicin-induced cardiomyopathy in male albino rats.

Worldwide, cancer is still the primary cause of death, and one of the most widely used anthracyclines for treating cancer is doxorubicin (DOX). But a major worry is DOX-induced cardiomyopathy, which is primarily resulted from an excess of reactive oxygen species. Heart sarcoplasmic reticulum calcium ion ATPase2a (SERCA2a) controls the amount of calcium ions stored in the sarcoplasmic reticulum (SR). This study aims to evaluate and compare the efficacy of SERCA2a gene modified adipose mesenchymal stem cell-derived exosomes (AMSCs-dE) to nontransfected AMSCs-dE, in DOX induced cardiomyopathy in adult male albino rat. Thirty one adult male albino rats were randomly divided into control group and DOX group that further subdivided into three DOX, AMSCs-dE and SERCA2a AMSCs-dE subgroups. AMSCs-dE were administered intravenously (IV). The levels of serum creatine kinase MB (CK-MB) were assessed after DOX injection and before sacrifice. Cardiac muscle samples were taken for histological analysis using Masson's trichrome and hematoxylin and eosin stains two months after the experiment. Proliferating cell nuclear antigen (PCNA) and connexin 43 were stained using immunohistochemistry. The expression of TNF and SERCA2a genes and proteins was measured by real-time polymerase chain reaction (PCR) and Western blot (Wb) analysis, respectively. Fluorescent microscopy demonstrated non-transfected and transfected exosomes labeled with PKH26 and GFP, respectively, in culture and cardiac muscle. DOX induced myocarditis progressing to degenerative and fibrotic changes in cardiac muscle that regressed in response to AMSCs-dE therapy. However, SERCA2a gene modified AMSCs-dE treatment reversed the mentioned parameters to nearly its normal level. These findings suggest that SERCA2a gene modification enhances the therapeutic efficacy of AMSCs-dE in treating DOX-induced cardiomyopathy.

Integration of Spinal Musculoskeletal System Parameters for Predicting OVCF in the Elderly: A Comprehensive Predictive Model.

Systematic literature review. To develop a predictive model for osteoporotic vertebral compression fractures (OVCF) in the elderly, utilizing current tools that are sensitive to bone and paraspinal muscle changes. A retrospective analysis of data from 260 patients from October 2020 to December 2022, to form the Model population. This group was split into Training and Testing sets. The Training set aided in creating a nomogram through binary logistic regression. From January 2023 to January 2024, we prospectively collected data from 106 patients to constitute the Validation population. The model's performance was evaluated using concordance index (C-index), calibration curves, and decision curve analysis (DCA) for both internal and external validation. The study included 366 patients. The Training and Testing sets were used for nomogram construction and internal validation, while the prospectively collected data was for external validation. Binary logistic regression identified nine independent OVCF risk factors: age, bone mineral density (BMD), quantitative computed tomography (QCT), vertebral bone quality (VBQ), relative functional cross-sectional area of psoas muscles (rFCSAPS), gross and functional muscle fat infiltration of multifidus and psoas muscles (GMFIES+MF and FMFIES+MF), FMFIPS, and mean muscle ratio. The nomogram showed an area under the curve (AUC) of 0.91 for the C-index, with internal and external validation AUCs of 0.90 and 0.92. Calibration curves and DCA indicated a good model fit. This study identified nine factors as independent predictors of OVCF in the elderly. A nomogram including these factors was developed, proving effective for OVCF prediction.

Subclinical Ocular Motility Dysfunction and Extraocular Muscle Changes in Inactive Graves' Orbitopathy.

This study aimed to investigate the presence of structural and functional changes in extraocular muscles (EMs) among patients with inactive Graves' orbitopathy (GO) classified according to the Clinical Activity Score (CAS). Sixty-seven patients with Graves' disease (GD) and inactive GO were included. The data collected included clinical parameters, thyroid function, autoantibody levels, EOM morphology via orbital ultrasound (US), and ocular motility. Patients were stratified into Red Filter Test (RFT)-positive or RFT-negative groups based on the presence or absence of latent diplopia during the RFT examination. Thirty-three patients (49.25%) exhibited latent diplopia on the RFT, despite not reporting double vision during standard ocular motility tests. Significant differences were observed between the two groups in terms of age, disease duration, intraocular pressure (IOP) elevation in up-gaze, and medial rectus muscle thickness (p < 0.05). No significant differences were found in thyroid status, TRAb and ATA levels, CASs, exophthalmos, or lateral rectus thickness between the two groups. This study revealed that in inactive GO, subclinical EM dysfunction and morphological changes may be present, which might not be apparent through routine ocular examinations. The RFT is effective in detecting latent diplopia, highlighting its utility in identifying subtle ocular motility issues and subclinical muscle involvement. Comprehensive evaluations combining functional tests like the RFT and imaging are essential for early detection of GO-related abnormalities, enabling tailored and prompt management and improving patient outcomes.

Understanding Secondary Sarcopenia Development in Young Adults Using Pig Model with Chronic Pancreatitis.

Chronic pancreatitis (CP) in young individuals may lead to disease-related secondary sarcopenia (SSARC), characterized by muscle loss and systemic inflammation. In this study, CP was induced in young pigs, and serum levels of key hormones, muscle fiber diameters in various muscles, and the mRNA expression of genes related to oxidative stress and programmed cell death were assessed. A decrease in muscle fiber diameters was observed in SSARC pigs, particularly in the longissimus and diaphragm muscles. Hormonal analysis revealed alterations in dehydroepiandrosterone, testosterone, oxytocin, myostatin, and cortisol levels, indicating a distinct hormonal response in SSARC pigs compared to controls. Oxytocin levels in SSARC pigs were significantly lower and myostatin levels higher. Additionally, changes in the expression of catalase (CAT), caspase 8 (CASP8), B-cell lymphoma 2 (BCL2), and BCL2-associated X protein (BAX) mRNA suggested a downregulation of oxidative stress response and apoptosis regulation. A reduced BAX/BCL2 ratio in SSARC pigs implied potential caspase-independent cell death pathways. The findings highlight the complex interplay between hormonal changes and muscle degradation in SSARC, underscoring the need for further research into the apoptotic and inflammatory pathways involved in muscle changes due to chronic organ inflammation in young individuals.

Correlation between self-reported low back pain and morphological changes in abdominal wall muscles

BACKGROUND: Morphological changes in the abdominal wall muscle in diastasis recti abdominis (DRA) patients with low back pain (LBP) symptoms and whether there is a wider interrectus distance (IRD) remain unclear. OBJECTIVE: The aim of this study was to determine the correlation between DRA severity and LBP and the morphological differences in abdominal wall muscles between patients who presented with symptoms of LBP and those who were asymptomatic. METHODS: A total of 57 postpartum DRA patients were enrolled, including 21 without LBP, 36 with LBP, and 30 healthy nulliparous women. The numerical rating scale (NRS) was used to evaluate the degree of LBP. The IRD and muscle thickness of the abdominal muscles were measured via an ultrasonography device at the end of a natural breathing cycle. RESULTS: The abdominal muscles of the rectus abdominis (RA), external oblique muscle (EO), and transversus abdominis (TrA) in the DRA patients were significantly thinner than those in the control group (p&lt; 0.05), whereas the difference in the internal oblique muscle (IO) was not significant (p&gt; 0.05). There were no statistically significant differences in abdominal muscle thickness or the IRD regardless of whether the patients with DRA had LBP symptoms, with similar findings between the NRS score and DRA severity (P&gt; 0.05). CONCLUSION: In DRA patients within one year postpartum, no significant difference was found in the severity of DRA or abdominal muscles, regardless of whether they were complicated by LBP symptoms. Shortening the IRD alone may not be beneficial for improving LBP symptoms in DRA patients. The relationship between DRA and LBP and the role of the abdominal muscles in postpartum LBP should be interpreted with caution.

Calorie restriction and rapamycin distinctly mitigate aging-associated protein phosphorylation changes in mouse muscles

Calorie restriction (CR) and treatment with rapamycin (RM), an inhibitor of the mTORC1 growth-promoting signaling pathway, are known to slow aging and promote health from worms to humans. At the transcriptome and proteome levels, long-term CR and RM treatments have partially overlapping effects, while their impact on protein phosphorylation within cellular signaling pathways have not been compared. Here we measured the phosphoproteomes of soleus, tibialis anterior, triceps brachii and gastrocnemius muscles from adult (10 months) and 30-month-old (aged) mice receiving either a control, a calorie restricted or an RM containing diet from 15 months of age. We reproducibly detected and extensively analyzed a total of 6960 phosphosites, 1415 of which are not represented in standard repositories. We reveal the effect of these interventions on known mTORC1 pathway substrates, with CR displaying greater between-muscle variation than RM. Overall, CR and RM have largely consistent, but quantitatively distinct long-term effects on the phosphoproteome, mitigating age-related changes to different degrees. Our data expands the catalog of protein phosphorylation sites in the mouse, providing important information regarding their tissue-specificity, and revealing the impact of long-term nutrient-sensing pathway inhibition on mouse skeletal muscle.

Characteristic of Paraspinal Muscle Change in Coronal Sub-type of Degenerative Lumbar Scoliosis and its Potential Clinical Significance.

Clarifying paraspinal muscle (PM) change in degenerative lumbar scoliosis (DLS) is positive to evaluate the progression of scoliosis. This research compares the characteristic of PM change among different coronal sub-types of DLS and explores its potential clinical significance. A total of 84 DLS patients between June 2019 to December 2021 were retrospectively analyzed. Patients were classified into three types based on the coronal balance distance (CBD): Type A, CBD <3 cm; Type B: C7 Plumb Line (C7PL) shifted to the concave side of the curve, and CBD >3 cm; Type C: C7PL shifted to the convex side of the curve, and CBD >3 cm. Fat infiltration rates in the multifidus (MS) and erector spinae (ES) at the apex of the main and fractional curves, and spinopelvic parameters were analyzed statistically. Pearson's or Spearman's correlation was applied to analyze the correlation between asymmetric degree of PM change and these parameters in three types. There were 62 cases with coronal sub-Type A, 6 cases with Type B, and 16 cases with Type C. Patients in Type B and C demonstrated higher fat infiltration in MS on the concave side of both the main and fractional curves when compared to those in Type A. The asymmetric degree of ES change was positively correlated with CBD at the apex of the main curve in Type B and at the apex of the fractional curve in Type C respectively, and that of MS was positively correlated with apical vertebral rotation, while negatively strong-correlated with pelvic incidence and sacral slope in Type C. PM fatty infiltration presented difference among varied coronal sub-types of DLS patients. The CBD in Type B and C patients was correlated with the asymmetric degree of ES change.

Evaluation of a passive back-support exoskeleton during in-bed patient handling tasks

This study evaluated the effects of a back-support exoskeleton on the trunk and hip joint angles, lower back muscle activity and heart rate during four patient handling tasks: assisting a patient from sitting to lying, laterally repositioning the patient and turning the patient in two directions. Eight participants performed these tasks with and without the exoskeleton. Results demonstrated a significant reduction in the lower back muscle activity, but less pronounced effects for other tasks involving minimal trunk flexion. Hip flexion angles were reduced for all tasks when the exoskeleton was worn. The amount of reduction in the muscle activity and changes in the trunk and hip angles varied by task. The exoskeleton did not affect the heart rate across all tasks. The exoskeleton appeared to be more effective in tasks requiring substantial trunk flexion, indicating its potential benefits for reducing lower back muscle strain during such activities.

Physiological analyses of swallowing changes due to chronic obstructive pulmonary disease in anesthetized male rats.

Chronic obstructive pulmonary disease (COPD) was previously known as chronic bronchitis and emphysema. It has various main symptoms, such as dyspnea, chronic cough, and sputum, and is often accompanied by dysphagia. Although many published clinical reports have described COPD-related dysphagia, the physiological mechanisms underlying swallowing changes due to COPD remain unclear. Therefore, we analyzed how COPD affects the swallowing reflex using COPD model rats. We performed an electrophysiological study of respiration and swallowing using COPD model induced by intratracheal administration of porcine pancreatic elastase and lipopolysaccharide in Sprague-Dawley male rats. To identify the respiration and swallowing responses, electromyographic activity was recorded from the diaphragm, digastric (Dig), and thyrohyoid (TH) muscles. We confirmed COPD using micro-computed tomography analysis and hematoxylin and eosin staining of the lungs. The duty cycle was defined as the ratio of the inspiration duration to the total respiratory duration. In COPD model rats, the duty cycle was significantly higher than that in control rats. The frequency of the swallowing reflex evoked by electrical stimulation of the superior laryngeal nerve during the inspiration phase was higher in COPD model rats than in control rats. Furthermore, long-term COPD altered Dig and TH muscle activity without pathological muscle change. Our results suggest that COPD increases the frequency of swallowing initiation during the inspiration phase. Furthermore, long-term COPD affects swallowing-related muscle activity without pathological muscle changes. These physiological changes may increase the risk of developing dysphagia. Further studies are necessary to clarify the mechanisms contributing to the functional changes in respiration and swallowing in COPD.

Exercise-induced changes in intramuscular total creatine concentration measured with 1H magnetic resonance spectroscopy: A pilot study.

Total amount of creatine (Cr) and phosphocreatine, or total creatine (tCr), may have a significant impact on the performance of skeletal muscles. In sports such as bodybuilding, it is popular to take Cr supplements to maintain tCr level. However, no study has explored the quantitative relationship between exercise intensity and the induced change in muscle's tCr. In this well-controlled study, straight-leg plantar flexion with specific load and duration was performed by 10 healthy subjects inside an MRI scanner, immediately followed by 1H MR spectroscopy (MRS) for measuring tCr concentration in gastrocnemius. For repeatability assessment, the experiment was repeated for each subject on two different days. Across all the subjects, baseline tCr was 46.6 ± 2.4 mM, ranging from 40.6 to 50.1 mM; with exercise, tCr significantly decreased by 10.9% ± 1.0% with 6-lb load and 21.0% ± 1.3% with 12-lb load (p < 0.0001). Between two different days, baseline tCr, percentage decrease induced by exercise with a 6-lb and 12-lb load differed by 2.2% ± 2.3%, 11.7% ± 6.0% and 4.9% ± 3.2%, respectively. In conclusion, the proposed protocol of controlled exercise stimulation and MRS acquisition can reproducibly monitor tCr level and its exercise-induced change in skeletal muscles. The measured tCr level is sensitive to exercise intensity, so can be used to quantitatively assess muscle performance or fatigue.

Effect of dietary supplementation of selenium-L-methionine on growth, antioxidant capacity and resistance to nitrite stress of spotted seabass (Lateolabrax maculatus) under two rearing water temperatures

A 10-week feeding trial, followed by 24-h nitrite stress, was performed to evaluate the effects of dietary selenium-L-methionine (Se-Met) on growth, Se accumulation, antioxidant capacity, transcripts of selenoproteins and histological changes of muscle as well as resistance to nitrite stress in spotted seabass (Lateolabrax maculatus) reared at optimal (27 °C) and high (33 °C) temperatures. Five experimental diets were formulated to contain 0, 0.9, 1.8, 3.5, and 7.0 mg Se-Met/kg. Each diet was fed to fish (2.60 ± 0.2 g) in two parallel treatments at 27 or 33 °C. The results showed that elevated temperature (33 °C) induced thermal stress in fish, and fish under thermal stress exhibited lower weight gain (WG) and hepatosomatic index (HSI) but a higher condition factor (CF) compared to those reared at 27 °C. However, the growth and feed utilisation were promoted in L. maculatus with 0.9 to 3.5 mg/kg Se-Met treatments. The protein and lipid content in the muscle increased with the dietary Se-Met level, and the total Se level in the whole body and muscle showed a linear increase with dietary Se-Met supplementation. Thermal stress changed the histology of the muscle, leading to raised levels of malondialdehyde (MDA), reduced antioxidant parameters in the serum and liver, and a decrease in the transcripts of selenoprotein genes in the muscle. Meanwhile, increased antioxidant capacity of serum and liver and up-regulated transcripts of selenoprotein of muscle were observed in L. maculatus reaching a maximum with 3.5 mg Se-Met/kg treatment. After 24 h of nitrite stress, thermal stress exacerbated oxidative damage caused by nitrite stress in L. maculatus. In contrast, dietary Se-Met enhanced the resistance to nitrite stress of L. maculatus fed with Se-Met enriched diets containing 0.9 to 1.8 mg Se-Met/kg. Based on the effects of dietary Se-Met on the growth, antioxidant capacity and resistance to nitrite stress of L. maculatus, this study suggests that the optimal range of Se-Met supplementation in L. maculatus diets is 1.80 to 2.39 mg Se-Met/kg of diet at 27 °C and 1.80 to 4.46 mg Se-Met/kg of diet at 33 °C.