The respiratory system as an exercise limiting factor in normal sedentary subjects

Summary The present study was undertaken to investigate the respiratory system as an exercise limiting factor. Breathing and cycle endurance (i.e. the time until exhaustion at a given performance level) as well as physical working capacity 170 (i.e. the exercise intensity corresponding to a heart rate of 170 beats -min^–1 on a cycle ergometer) were determined in four healthy sedentary subjects. Subsequently, the subjects trained their respiratory system for 4 weeks by breathing daily about 901 · min^–1 for 30 min. Otherwise they continued their sedentary lifestyle. Immediately after the respiratory training and 18 months later, all performance tests carried out at the beginning of the study were repeated. The respiratory training increased breathing endurance from 4.2 (SD 1.9) min to 15.3 (SD 3.8) min. Cycle endurance was improved from 26.8 (SD 5.9) min to 40.2 (SD 9.2) min whereas physical working capacity 170 remained essentially the same. During the endurance cycling test in the respiratory untrained state, the subjects continuously increased their ventilation up to hyperventilation [ventilation at exhaustion = 96.9 (SD 23.6) 1 · min^–1] while after the respiratory training they reached a respiratory steady-state without hyperventilation [ventilation at exhaustion = 63.3 (SD 14.5) 1 · min^–1]. The absence of this marked hyperventilation was the cause of the impressive increase of cycle endurance in normal sedentary subjects after respiratory training. The effects gained by the respiratory training were completely lost after 18 months. Our results indicated that the respiratory system was an exercise limiting factor during an endurance test in normal sedentary subjects.     

Systemic and mucosal antibody responses specific to SARS-CoV-2 during mild versus severe COVID-19

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氟中毒家兔肾脏功能与细胞周期的变化

目的观察氟中毒家兔肾脏细胞周期和功能、离子代谢的变化。方法经饮水投氟复制氟中毒模型。采用全自动生化分析仪检测血清内反映肾功能的指标和相关的离子代谢,以及采用流式细胞仪检测细胞周期。结果氟中毒家兔尿液中反映肾小管损伤的γ-谷胺酰转移酶明显升高;而BUN、Crea变化不明显。氟中毒家兔离子代谢紊乱,其中K 、Ca2 、P3 代谢紊乱尤为明显;高剂量氟组和中剂量氟组家兔肾细胞G2期细胞数较对照组显著增多,高剂量氟组的G1期细胞数明显减少。结论氟对肾组织损害部位主要是肾小管,即主要影响肾的吸收功能;过量氟通过影响DNA的合成阻碍了细胞进入分裂期,促进细胞死亡,从而影响肾脏的功能。     

薄壁构件的高温低周疲劳寿命的预测与验证

提出了文题的计算模型,它采用非线性弹塑性蠕变有限元法,计算构件危险点在高温及周期保载的交变载荷谱作用下的应力应变响应,以应变范围区分法累积损伤,从而求出构件的疲劳寿命,并以带孔矩形薄板为例作了计算与验证,结果吻合较好,可供工程应用。     

<Emphasis Type="Italic">V</Emphasis>O<Subscript>2</Subscript>max during successive maximal efforts

The concept of VO₂max has been a defining paradigm in exercise physiology for >75 years. Within the last decade, this concept has been both challenged and defended. The purpose of this study was to test the concept of VO₂max by comparing VO₂ during a second exercise bout following a preliminary maximal effort exercise bout. The study had two parts. In Study #1, physically active non-athletes performed incremental cycle exercise. After 1-min recovery, a second bout was performed at a higher power output. In Study #2, competitive runners performed incremental treadmill exercise and, after 3-min recovery, a second bout at a higher speed. In Study #1 the highest VO₂ (bout 1 vs. bout 2) was not significantly different (3.95 ± 0.75 vs. 4.06 ± 0.75 l min⁻¹). Maximal heart rate was not different (179 ± 14 vs. 180 ± 13 bpm) although maximal V _E was higher in the second bout (141 ± 36 vs. 151 ± 34 l min⁻¹). In Study #2 the highest VO₂ (bout 1 vs. bout 2) was not significantly different (4.09 ± 0.97 vs. 4.03 ± 1.16 l min⁻¹), nor was maximal heart rate (184 + 6 vs. 181 ± 10 bpm) or maximal V _E (126 ± 29 vs. 126 ± 34 l min⁻¹). The results support the concept that the highest VO₂ during a maximal incremental exercise bout is unlikely to change during a subsequent exercise bout, despite higher muscular power output. As such, the results support the “classical” view of VO₂max.     

月经周期与调周法（续1）

本文分析了行经期病理变化，冲任子宫功能失调重阳必阴的转化失常、圆运动生物钟节律失常对月经的影响。论述行经期的治疗方法，一般调经方剂及药物；治疗中要注意重阳及脂膜湿浊，同时还必须认为到初中末三个时期的不同；介绍了几种特殊的调经方法药物，如逐瘀破膜法，温经止痛法，清肝调经法、清降通瘀法、补气调经法、化痰利湿法等。在运用调经方法的同时，务必注意到掌握服药的关键时期，及主次药物的剂量，以及行经期的保护措施     

脊柱矫形器测力监控装置的研制与应用

[目的]利用容珊原理研制支撑杆电子数显测力监控装置,并将其应用于新型脊柱矫形器,对强直性脊柱炎导致驼背畸形患者进行矫形治疗,探讨矫形器的作用机理,并进行临床生物力学研究。[方法](1)利用容珊原理研制位电容压力传感器,组装成支撑杆测力监控装置。(2)应用该装置对新型脊柱矫形器进行作用机理研究,对10名正常人进行模拟测试,获得力学参数值,用以观察患者在治疗期间的对比变化量。(3)应用装有测力监控装置的矫形器对13例强直性脊柱炎导致驼背畸形患者进行矫形治疗,临床观察2周,测定其身高、驼背畸形角度、柄耻间距及剑耻间距的改变情况。[结果]利用支撑杆测力监控装置进行实验研究显示,新型脊柱矫形器是一种组合加力装置,其矫形作用是由牵引力和挤压力共同完成的。其牵引力约为4kg,挤压力约为18kg。临床研究显示患者身高的改善幅度为2～16cm,平均6.1cm;X线片显示驼背畸形角度平均改善12.1°;柄耻间距平均增长5.1cm,剑耻间距平均增长4.3cm。[结论]该支撑杆测力监控装置不仅能科学地探索矫形器支撑框架的力学规律,还能对其支撑力进行实时监控,从而指导临床治疗,较好的解决了脊柱矫形治疗中的定量问题。     

心肺功能综合评定对优秀径类运动员选才及训练的指导作用

对我国34名优秀径类运动员(男23,女11)进行递增式踏车试验,连续观察(?)E,气促指数,心率,心搏效率,氧脉,(?)O_2max,无氧阈((?)E/(?)O_2,(?)CO_2/(?)O_2曲线的拐点),结果显示,我国男子中长跑运动员(?)O_2显著低于世界水平,而女子长跑运动员则接近于世界水平。综合心肺功能评定可以发现运动员心肺或肌肉功能薄弱环节,为青少年选材提供依据,并可用于评价训练效果。     

INTRA-OCULAR PRESSURE CHANGES AF-TER B-BLOCKER EYE DROPS INSTILLA-TION AND BICYCLE ERGOMETER EXER-CISE

Purpose: To evaluate the additive IOP effect of physical aerobic exercise (bicycle ergometer), in healthy individuals, after the in- stillation of b-blockers. Material: 20 healthy individuals. Methods: The IOP was measured before and 2 hours after the instillation of eye drops (b-blockers) in the right eye (OD) of the individuals.. The IOP was measured again within 5 minutes after the completion of physical exercise on a bicycle ergometer (about 10 minutes of duration - till exhaustion). Results: The instillation of b-blocker eye drops in the right eye was followed by an IOP decrease after 2 hours. The IOP decreased further more after the performance of the bicycle ergometer exercise. Mean IOP before the instillation of b-blocker. right eyes: 16.25, left eyes: 16.15. Mean IOP after the instillation of b-blocker. right eyes: 12.35 (decrease ranged from 3 to 5 mm Hg), left eyes: 14.20.. The IOP lowering effect after the bicycle ergometer exercise for the right eyes ranged from 1 to 5 mmHg. Mean IOP 10.20.     

平阳霉素(博菜霉素A5)对同步化的CHO细胞的敏感周期时相的研究

平阳霉素(博莱霉素A₅)作用于同步化的各个周期时相的CHO细胞。结果用集落形成率来表示。研究表明平阳霉素对M期细胞最为敏感,其敏感顺序为M>G₂>S>G₁。实验使用的细胞同步化方法是用有丝分裂选择法收集M期细胞;用2 mMTdR双阻断法获得S期同步化细胞,再由M期和S期细胞分别向后推移1.5～2小时和7小时以获得G₁期和G₂期的同步细胞,并附以有丝分裂指数(MI)和标记指数(LI)检测各周期时相细胞的同步化程度。