Eff ects of early standardized enteral nutrition on preventing acute muscle loss in the acute exacerbation of chronic obstructive pulmonary disease patients with mechanical ventilation

BACKGROUND:To investigate the eff ects of early standardized enteral nutrition(EN)on the crosssectional area of erector spine muscle(ESMcsa),plasma growth diff erentiation factor-15(GDF-15),and 28-day mortality of acute exacerbation of chronic obstructive pulmonary disease(AECOPD)patients with invasive mechanical ventilation(MV).METHODS:A total of 97 AECOPD patients with invasive MV were screened in the ICUs of the First People's Hospital of Lianyungang.The conventional EN group(stage Ⅰ)and early standardized EN group(stage Ⅱ)included 46 and 51 patients,respectively.ESMcsa loss and GDF-15 levels on days 1 and 7 of ICU admission and 28-day survival rates were analyzed.RESULTS:On day 7,the ESMcsa of the early standardized EN group was significantly higher than that of the conventional EN group,while the plasma GDF-15 levels were significantly lower than those in the conventional EN group(ESMcsa:28.426±6.130 cm^(2) vs.25.205±6.127 cm^(2);GDF-15:1661.608±558.820 pg/mL vs.2541.000±634.845 pg/mL;all P<0.001).The 28-day survival rates of the patients in the early standardized EN group and conventional EN group were 80.40%and 73.90%,respectively(P=0.406).CONCLUSION:ESMcsa loss in AECOPD patients with MV was correlated with GDF-15 levels,both of which indicated acute muscular atrophy and skeletal muscle dysfunction.Early standardized EN may prevent acute muscle loss and intensive care unit-acquired weakness(ICU-AW)in AECOPD patients.

Quantification Threshold Pixel Technique of Magnetic Resonance Imaging in Paraspinal Muscles Atrophy among Discopathy Patients

Purpose: To evaluate the relationship between lumbosacral discopathy status and paraspinal atrophic changes (Cross-sectional area (CSA) and fatty infiltration (FI)) among different age groups. Materials and Methods: We retrospectively evaluated 200 patients with confirmed discopathy who were examined by lumbosacral Magnetic Resonance Imaging (MRI) at the two main governmental hospitals in Gaza Strip. Using ImageJ software and quantification threshold technique, we measured the CSA and FI of paraspinal muscles {multifidus (MF) & erector spinae (ES)}. The interpretation of MRI images was performed by two radiologists with a good inter-observer agreement between the radiological discopathy findings. Results: The highest percentage and severity of discopathy were noticed at the level of L4/5 (89.5%), followed by L5/S1 (14.5%). The FI is increased towards lower levels of L3/4 to L5/S1. No correlation was found between discopathy level, the severity of discopathy, and CSA of MF & ES muscles. In contrast, a correlation was observed between FI of MF & ES muscles, discopathy level, and severity. Also, the results illustrated no significant relation was observed between CSA of MF & ES muscles and age groups (P > 0.05), while a significant correlation was reported between FI and age groups (P Conclusion: The MRI quantification threshold pixel technique for paraspinal muscles reflected the atrophic changes like CSA and FI in discopathy patients.

自噬在电针对大鼠失神经性肌肉萎缩的肌细胞形态计量学影响中的作用

目的:研究自噬在电针治疗神经损伤后肌肉萎缩中的作用。方法:通过手术造成大鼠实验性坐骨神经钳夹伤模型,采用电针治疗、自噬抑制剂三甲基腺嘌呤(3-MA)干预等措施,不同时间点取材进行腓肠肌组织学观察和腓肠肌肌细胞截面积的测算。结果:腓肠肌肌组织的HE染色切片显示,第1、2天时,各组腓肠肌组织形态大小正常;第7天时,除正常组外,其余各组腓肠肌组织形态明显变小萎缩;第28天时,电针组的腓肠肌组织形态完整性较好,而电针联合自噬抑制剂组的腓肠肌组织形态大小和完整性较其他各组要差。腓肠肌肌细胞截面积的组间比较显示,第1、2天时,正常组腓肠肌肌细胞截面积与其他各组比无差异;第7、28天时,正常组腓肠肌肌细胞截面积与其他各组比明显变小,P<0.01,有显著性差异;第7、28天时,电针联合自噬抑制剂组肌细胞截面积与电针组比小,P<0.05,有差异。组内比较显示,模型组、电针组和电针联合自噬抑制剂组在第7、28天时的肌细胞截面积较第1天比明显变小,P<0.01,有显著性差异。结论:坐骨神经损伤后腓肠肌短期不萎缩,但中长期萎缩明显,在此过程中,电针可延缓腓肠肌萎缩,使腓肠肌保持形态相对完整;在相同电针情况下,抑制自噬反应会对维持腓肠肌正常形态造成一定负面影响,说明电针可能通过促进细胞自噬来改善腓肠肌组织形态。

亮氨酸和α-酮戊二酸对小鼠体重、血清及脏器的影响

选取40只4周龄C57BL/6雄性小鼠,随机分为4组。对照组正常饮水,其他组小鼠分别在水瓶中加入1.0%的α-酮戊二酸(Ⅰ组)、1.8%的亮氨酸(Ⅱ组)、1.8%的亮氨酸和1.0%的α-酮戊二酸(Ⅲ组)。试验期为35d。结果表明:①Ⅲ组的体重比对照组、Ⅰ组和Ⅱ组分别降低了8.7%,10.1%,10.4%;②Ⅲ组的血清白蛋白含量比对照组、Ⅰ组和Ⅱ组显著提高(P<0.05);③Ⅲ组的心脏指数比对照组、Ⅰ组和Ⅱ组分别提高了19.3%,13.6%,15.2%;④Ⅲ组的腹部脂肪指数比对照组、Ⅰ组和Ⅱ组分别降低了24.1%,10.0%,6.7%,Ⅲ组的腓肠肌横截面积比对照组、Ⅰ组和Ⅱ组分别提高了46.9%,20.2%,27.9%。说明亮氨酸和α-酮戊二酸两者联合能减轻小鼠体重,加强器官对脂肪的利用,增加腓肠肌纤维横截面积。

Effects of resistance training performed to repetition failure or non-failure on muscular strength and hypertrophy:A systematic review and meta-analysis

Purpose:We aimed to perform a systematic review and meta-analysis of the effects of training to muscle failure or non-failure on muscular strength and hypertrophy.Methods:Meta-analyses of effect sizes(ESs)explored the effects of training to failure vs.non-failure on strength and hypertrophy.Subgroup meta-analyses explored potential moderating effects of variables such as training status(trained vs.untrained),training volume(volume equated vs.volume non-equated),body region(upper vs.lower),exercise selection(multi-vs.single-joint exercises(only for strength)),and study design(independent vs.dependent groups).Results:Fifteen studies were included in the review.All studies included young adults as participants.Meta-analysis indicated no significant difference between the training conditions for muscular strength(ES=-0.09,95%confidence interval(95%CI):-0.22 to 0.05)and for hypertrophy(ES=0.22,95%CI:-0.11 to 0.55).Subgroup analyses that stratified the studies according to body region,exercise selection,or study design showed no significant differences between training conditions.In studies that did not equate training volume between the groups,the analysis showed significant favoring of non-failure training on strength gains(ES=-0.32,95%CI:-0.57 to-0.07).In the subgroup analysis for resistance-trained individuals,the analysis showed a significant effect of training to failure for muscle hypertrophy(ES=0.15,95%CI:0.03-0.26).Conclusion:Training to muscle failure does not seem to be required for gains in strength and muscle size.However,training in this manner does not seem to have detrimental effects on these adaptations,either.More studies should be conducted among older adults and highly trained individuals to improve the generalizability of these findings.

Design and Analysis of Osmosis-based Artificial Muscle

This paper presents the design and analysis of an osmosis-based artificial muscle inspired by the leaf movements of Mimosa pudica.M.pudica's leaves quickly contract using osmosis pressure in the pulvinus when they are stimulated.We analyzed and simulated an osmosis system to identify the factors for fast osmosis reactions and designed a prototype artificial muscle based on the results.The osmosis phenomenon was mathematically modeled,analyzed,and verified through several experiments.The analysis shows that fast osmosis responses require a large diffusion coefficient with a high-flux membrane or small ratio of the cross-sectional area to the volume of the osmosis system.We designed a micro-scale system to achieve the required ratio.The contraction and relaxation of the artificial muscle are realized by changes of the local concentration of potassium ions,which can be aggregated by a controllable electric field.As a result,the artificial muscle shows controllable behavior with fast reactions.

基于^(1)H NMR代谢组学技术结合网络药理学的恒山黄芪抗疲劳药效比较及调控牛磺酸代谢的机制初探

比较评价恒山黄芪的抗疲劳药效并初步揭示其通过调控牛磺酸代谢发挥抗疲劳的分子机制。本研究首先比较评价了广灵黄芪与浑源黄芪的药效差异,其次采用^(1)H NMR代谢组学技术并结合统计学的方法对不同组小鼠腓肠肌组织代谢产物进行分析与指认,找出受黄芪调控的差异代谢物,并借助Metscape预测其上游靶标。通过整合课题组前期基于网络药理学的黄芪抗疲劳潜在靶点,采用Cytoscape软件构建黄芪潜在抗疲劳靶点-共有靶点-差异代谢物相关靶点网络图,通过度值(degree)筛选关键靶点。最后依据共有靶点反推确定关键差异代谢物,并将其输入Metaboanalyst网站中进行通路富集分析,初步阐明分子机制。结果显示,黄芪干预能够明显改善小鼠力竭游泳时间,升高肝糖原并降低尿素氮水平,且广灵黄芪与浑源黄芪药效差异较小,即同属恒山山脉所产的黄芪质量较均一。进一步小鼠腓肠肌组织提取物指纹共指认34种代谢物,统计结果表明19个差异代谢物在恒山黄芪干预后发生显著回调。结合网络药理学最终明确恒山黄芪主要通过调控GAD1干预牛磺酸及次牛磺酸代谢来发挥抗疲劳作用。本研究结合^(1)H NMR代谢组学技术与网络药理学比较评价了恒山黄芪的抗疲劳药效,并初步揭示了其调控牛磺酸代谢抗疲劳的分子机制,为恒山黄芪的资源利用以及抗疲劳相关产品研发提供理论依据。本文涉及的动物实验操作均遵循山西大学动物伦理委员会的规定并通过动物实验伦理审查(批准号:SXULL2021028)。

Physiological Responses to Agonist-Antagonist Superset Resistance Training

Purpose To investigate the physiological responses to low-load,superset resistance training(two exercises for the agonist and antagonist muscles performed without rest between exercises)to failure using elastic bands.Methods Twenty-three athletes were randomized to either a superset group(S,n=12,average age:19.8±1.5 years)or a traditional set group(T,n=11,average age:20.1±1.4 years).Strength,cross-sectional area(CSA)and muscular endurance of the biceps and triceps brachii were assessed before and after 8 weeks.Acute responses(muscle thickness)were measured during one testing session.Results Muscle thickness of the biceps significantly increased in both T group(P<0.05)and S group(P<0.05)after a single bout of Training.The triceps did not show significant increases in either T group(P>0.05)or S group(P>0.05).Blood lactate also increased in both groups after one bout of training(T:from 1.3±0.3 to 5.5±2.4 mmol/L,S:from 1.4±0.5 to 5.1±1.5 mmol/L,P<0.05).After 8-week training,both groups showed significant increases in the biceps(T:13.2%±5.0%;S:12.9%±7.3%,P<0.05)and triceps(T:9.5%±9.3%,S:4.8%±4.1%,P<0.05)without differences between groups.Increases in one repetition maximum for the bench press(7.8%±6.5%,P<0.05)and maximal voluntary contraction for the arm extensors(9.3%±11.6%,P<0.05)were observed for the T group only.Increases in muscular endurance were observed only in the S group for the bench press(26.0%±19.1%,P<0.05)and the barbell curl(17.2%±16.6%,P<0.05).Conclusions Superset training may enhance muscular endurance while attenuating maximal strength gains.There does not appear to be a hypertrophic benefit to performing superset training,but it may provide a time-efficient strategy to achieve adaptations in muscle mass.