体脂量是绝经后女性股骨近端骨强度的决定因素

正Lower body weight or body mass index(BMI)has been known to be higher risk of developing osteoporosis and low-energy fractures via mechanical loading and other factors in both men and women[1].Recently,there have been new insights into the relationships between body composition and bone health.However,most of the previous studies regarding the relative effect of body composition on bone mass yielded inconsistent     

Strength estimation of a moving 125Iodine source during implantation in brachytherapy: application to linked sources

This study sought to demonstrate the feasibility of estimating the source strength during implantation in brachytherapy. The requirement for measuring the strengths of the linked sources was investigated. The utilized sources were ¹²⁵I with air kerma strengths of 8.38–8.63 U (μGy m² h^–1). Measurements were performed with a plastic scintillator (80 mm × 50 mm × 20 mm in thickness). For a source-to-source distance of 10.5 mm and at source speeds of up to 200 mm s^–1, a counting time of 10 ms and a detector-to-needle distance of 5 mm were found to be the appropriate measurement conditions. The combined standard uncertainty (CSU) with the coverage factor of 1 (k = 1) was ∼15% when using a grid to decrease the interference by the neighboring sources. Without the grid, the CSU (k = 1) was ∼5%, and an 8% overestimation due to the neighboring sources was found to potentially cause additional uncertainty. In order to improve the accuracy in estimating source strength, it is recommended that the measurment conditions should be optimized by considering the tradeoff between the overestimation due to the neighboring sources and the intensity of the measured value, which influences the random error.     

Time Course Analysis of the Effects of Botulinum Neurotoxin Type A on Pain and Vasomotor Responses Evoked by Glutamate Injection into Human Temporalis Muscles

The effect of botulinum neurotoxin type A (BoNTA) on glutamate-evoked temporalis muscle pain and vasomotor responses was investigated in healthy men and women over a 60 day time course. Subjects participated in a pre-BoNTA session where their responses to injection of glutamate (1 M, 0.2 mL) and saline (0.2 mL) into the temporalis muscles were assessed. On Day 1, BoNTA (5 U) was injected into one temporalis muscle and saline into the contralateral temporalis muscle, in a randomized order. Subjects then received intramuscular injections of glutamate (1 M, 0.2 mL) into the left and right temporalis muscles at 3 h and subsequently 7, 30 and 60 days post-injection of BoNTA. Pain intensity, pain area, and neurogenic inflammation (skin temperature and skin blood perfusion) were recorded. Prior to BoNTA treatment, glutamate evoked significantly greater pain and vasomotor reactions (P < 0.001) than saline. BoNTA significantly reduced glutamate-evoked pain intensity (P < 0.05), pain area (P < 0.01), skin blood perfusion (P < 0.05), and skin temperature (P < 0.001). The inhibitory effect of BoNTA was present at 3 h after injection, peaked after 7 days and returned to baseline by 60 days. Findings from the present study demonstrated a rapid action of BoNTA on glutamate-evoked pain and neurogenic inflammation, which is in line with animal studies.     

BNIP3介导骨骼肌线粒体自噬：不同强度运动的影响

文题释义： BNIP3：隶属于Bcl-2蛋白超家族,是一种线粒体促凋亡蛋白,可与腺病毒转录基因E1B编码的蛋白或Bcl-2蛋白结合。可起到促进细胞凋亡、引起线粒体去极化和自噬,在机体中发挥重要作用。 线粒体自噬：线粒体是细胞的能量工厂,其功能还涉及细胞代谢、信号传导、分化、生长、凋亡和死亡等重要过程。线粒体自噬(mitophagy)是细胞清除损伤或衰老的线粒体,并循环利用其组成元素的过程;与衰老、神经退行性疾病和癌症等诸多生理病理过程密切相关。 背景：不同强度运动对机体可产生不同的影响,运动后骨骼肌的变化也不明确,而运动中机体的生理变化机制更是目前研究的热点。 目的：探讨不同强度运动对大鼠骨骼肌质量的影响以及BNIP3介导的骨骼肌线粒体自噬在维持骨骼肌质量中的作用。 方法：实验方案经北京体育大学动物实验伦理委员会批准。8周龄雄性SD大鼠24只,随机分为对照组、中等强度运动组(5°,15 m/min,1 h,60%VO_2max)和大强度运动组(5°,35 m/min,20 min,85%VO_2max),每组8只,每周运动6次。4周运动后取大鼠比目鱼肌和腓肠肌,称量湿质量,免疫荧光检测肌纤维横截面积,Western Blot检测比目鱼肌和腓肠肌BNIP3、p62和LC3蛋白的表达。 结果与结论：①腓肠肌湿质量大强度运动组和中等强度运动组显著低于对照组(P < 0.01);②比目鱼肌肌纤维横截面积大强度运动组显著小于对照组(P < 0.01);腓肠肌肌纤维横截面积中等强度运动组和大强度运动组均显著大于对照组(P < 0.01);③中等强度运动诱导线粒体自噬增加,表现为BNIP3、LC3-Ⅱ/LC3-Ⅰ值相较对照组表达增加(P < 0.05),而p62较对照组表达下降(P < 0.05);大强度运动组LC3-Ⅱ/LC3-Ⅰ、p62的表达量相较4周中等强度运动分别为上升和下降(P < 0.05),但其BNIP3的表达量却下降(P < 0.05);④结果表明,4周中等强度运动可促进骨骼肌通过BNIP3途径的线粒体自噬清除损伤线粒体,维持骨骼肌功能。4周大强度运动自噬水平更高,但可能对骨骼肌产生不利影响。 ORCID: 0000-0003-3836-3002(于亮) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

骨骼肌肥大的核糖体生物发生机制及其运动适应

文题释义：核糖体生物发生：是一个高度复杂的过程,涉及核糖体的从头合成,是细胞必不可少的活动过程,主要包括3个关键步骤：①rDNA转录;②新合成的47S pre-rRNA加工;③核糖体蛋白与各自核糖体亚基组装后的亚基成熟。核糖体生物发生在细胞生长中有着重要作用,在肌肉肥大过程中细胞大小增加需要核糖体生物发生的增加。骨骼肌收缩活动可以诱发核糖体生物发生,从而对骨骼肌质量的控制起重要作用。骨骼肌肥大：在各种外部和内部刺激下,骨骼肌细胞外基质重塑,蛋白质合成代谢和分解代谢加强,但合成代谢远强于分解代谢,使蛋白质净合成增加,肌纤维增粗、肌肉质量增加、骨骼肌肥大。骨骼肌是重要的内分泌器官,与人体的新陈代谢密切相关,骨骼肌肥大除可提高人体的运动表现外,还能减少疾病和损伤的发生、提高生活质量。抗阻训练结合营养补充是诱导骨骼肌肥大、增强肌肉力量的最常用方法。 背景：研究证据表明,骨骼肌收缩活动可以诱发核糖体生物发生,从而对骨骼肌质量的控制起重要作用。 目的：概述骨骼肌肥大与核糖体生物发生的主要机制,骨骼肌核糖体生物发生的上游调控信号,以及运动对核糖体生物发生的影响,探讨运动诱导骨骼肌肥大的核糖体生物发生机制。 方法：检索CNKI、万方、PubMed等数据库关于运动、骨骼肌肥大及核糖体生物发生的相关研究,中文检索词为“运动,抗阻训练,骨骼肌肥大,蛋白质合成,核糖体生物发生”等;英文检索词为“exercise,resistance training,skeletal muscle hypertrophy,protein synthesis,ribosome biogenesis”等,检索时限为1999至2019年,按照纳入标准和排除标准对搜索文献进行筛选。结果与结论：①核糖体生物发生作为翻译能力的主要来源,在肌肉生长中起着重要的作用;②单次的抗阻运动就可以对骨骼肌核糖体生物发生产生影响;长期抗阻运动会增加成熟核糖体RNA的丰度,导致总RNA的浓度增加,从而促进骨骼肌的生长;③核糖体生物发生可能是调节抗阻训练诱导的骨骼肌肌肉肥大的关键分子机制;④中等运动量抗阻训练就可以诱导骨骼肌肥大的适应性增强,这种肥大与总RNA量的依赖性调节有关,表明核糖体的生物发生调节了训练量与肌肉肥大的量效关系。 ORCID: 0000-0001-6938-5111(杨军) 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

Inhibition of hypoxia-induced proliferation of pulmonary arterial smooth muscle cells by a mTOR siRNA-loaded cyclodextrin nanovector

The proliferation of pulmonary arterial smooth muscle cells (PASMCs) is a key pathophysiological component of vascular remodeling in pulmonary arterial hypertension (PAH), an intractable disease, for which pharmacotherapy is limited and only slight improvement in survival outcomes have achieved over the past few decades. RNA interference provides a highly promising strategy to the treatment of this chronic lung disease, while efficient delivery of small interfering RNA (siRNA) remains a key challenge for the development of clinically acceptable siRNA therapeutics. With the aim to construct useful nanomedicines, the mammalian target of rapamycin (mTOR) siRNA was loaded into hybrid nanoparticles based on low molecular weight (Mw) polyethylenimine (PEI) and a pH-responsive cyclodextrin material (Ac-aCD) or poly(lactic-co-glycolic acid) (PLGA). This hybrid nanoplatform gave rise to desirable siRNA loading, and the payload release could be modulated by the hydrolysis characteristics of carrier materials. Fluorescence observation and flow cytometry quantification suggested that both Ac-aCD and PLGA nanovectors (NVs) may enter PASMCs under either normoxia or hypoxia conditions as well as in the presence of serum, with uptake and transfection efficiency significantly higher than those of cationic vectors such as PEI with Mw of 25 kDa (PEI25k) and Lipofectamine 2000 (Lipo 2k). Hybrid Ac-aCD or PLGA NV containing siRNA remarkably inhibited proliferation and activated apoptosis of hypoxic PASMCs, largely resulting from effective suppression of mTOR signaling as evidenced by significantly lowered expression of mTOR mRNA and phosphorylated protein. Moreover, these hybrid nanomedicines were more effective than commonly used cationic vectors like PEI25k and Lipo 2k, with respect to cell growth inhibition, apoptosis activation, and expression attenuation of mTOR mRNA and protein. Therefore, mTOR siRNA nanomedicines based on hybrid Ac-aCD or PLGA NV may be promising therapeutics for diseases related to hypoxic abnormal growth of PASMCs.