Functional State of 11- to 12-Year-Old Schoolchildren under Conditions of Intense Academic Load Assessed by Heart Rate Variability

The functional state of sixth-grade children was estimated on the basis of heart rhythm variability data. It was found that the heart rate variability was closely correlated with learning progress during both intensive and nonintensive methods of education. The highest adaptation tension was observed in children with good learning progress during intensive methods of education.     

Seasonal Changes in Heart Rate Variability in 11- to 13-Year-Old Girls

Heart rate variability (HRV) was assessed each quarter during a year in 11- to 13-year-old girls with a Valenta medical diagnostic system. The HRV was highest in winter and lowest in summer (in 12-year-old girls) and autumn (in 11- and 13-year-old girls), indicating seasonal changes in the degree of β-adrenergic effects on the heart (lowest in winter and highest in summer and/or autumn). The changes were most pronounced in 11-year-old girls, i.e., at the onset of puberty. Seasonal changes in the HRV can be explained by changes in the blood levels of direct and indirect endogenous modulators of chemoresponsiveness and are considered to be a mechanism of human adaptation to external conditions.__________Translated from Fiziologiya Cheloveka, Vol. 31, No. 4, 2005, pp. 43–49.Original Russian Text Copyright © 2005 by Kaisina, Sizova, Tsirkin, Trukhina.     

Visual Acuity and the Crowding Effect in 8- to 17-Year-Old Schoolchildren

Visual acuity (VA) in 292 schoolchildren aged 8–17 years was measured using Landolt Cs, E letters, and rectangular gratings. With the forced choice procedure, the VA measured with Landolt Cs was 1.4 times higher than with other targets, suggesting analysis of the whole image rather than its gaps by the visual system. In addition, the effect of surrounding images on VA estimates was studied with Landolt Cs, E letters, and gratings surrounded by bars, E letters, and gratings, respectively. A crowding effect, i.e., a worse perception of test objects surrounded by other images, was revealed. However, the perception of Landolt Cs, E letters, and gratings showed age-dependent differences. The separation between the stimulus and surrounding images at which the perception of gratings and other images worsened decreased with age increasing up to 16–17 and 12 years, respectively. The age-related differences were explained by the immaturity of selective-attention mechanisms.     

Weekly Changes in Psychophysiological Variables of 8- to 10-Year-Old School Girls

Three groups of schoolgirls 8, 9, and 10 years of age, respectively, self assessed sleep onset/offset and duration, as well as oral temperature and a set of cognitive measures, at school at 09:00, 11:00, 14:00, and 16:00 h on Mondays, Tuesdays, Thursdays, and Fridays (and/or Saturday) for 2 consecutive weeks (spring 1987 and 1989). The scores of a letter cancellation test exhibited neither daily nor weekly temporal variation at the age of 8 years [analysis of variance (ANOVA), p > 0.05]. In contrast, in the 10-year-olds, changes as a function of both time of day (peak time 14:00–16:00 h) and day of week (peak day Tuesday-Friday) were substantiated. Moreover, the time of best performance on the letter cancellation test varied systematically according to the day of the week (ANOVA, p = 0.000). Day of the week changes in the observed duration of sleep, self-rated fatigue, drowsiness, and attention changes were not detected in any of the age groups. It is hypothesized that temporal performance variations in the girls during the 7-day period was age related.     

Atrial Pacing to Control Heart Rate and Rhythm in Acute Cardiac Conditions

Increasing the heart rate by a bedside atrial pacing technique was successfully utilized to treat serious cardiac arrhythmia or failure in 13 patients. Nine of these had ventricular arrhythmia refractory to drugs. Seven had evidence of sinus node depression or disease since their sinus pacemaker was below 70 beats per minute under decompensated conditions. In five, coronary artery disease was associated with the bradycardia and in two, digitalis toxicity was related to depression of the intrinsic pacemaker rate. Two patients in the coronary group required implantation of a permanent demand ventricular pacemaker. Hemodynamic studies were performed in seven patients. Only one patient had no increase in cardiac output with pacing rates above his resting rate. The other six patients showed an increase in cardiac output from 22 to 81% at paced rates between 70 and 125/minute. The duration of pacing ranged from one hour to 14 days and averaged five days.     

Th17细胞分化、调节及效应研究进展

Th17细胞作为一个不同于Th1、Th2的细胞亚群,已经被证实在自身免疫病、感染等疾病中发挥重要的作用.为了进一步认识Th17细胞的效应机制,近来对于Th17细胞的分化及调节进行了深入的研究,证实TGF-β与IL-6或者IL-21的协同作用是诱导Th17细胞分化的关键因素,而IL-23在促进IL-17分泌,增强Th17细胞效应功能方面发挥重要作用.与Th1、Th2、Treg细胞特异性的转录调节因子T-bet、GATA3、Foxp3相对应,现证实ROR-γt(retinoid-related orphanreceptors-γr)是促进Th17细胞分化、调节其功能的特异性转录调节因子.Th17细胞通过分泌IL-17A、IL-17F、IL-21、IL-22、IL-6、TNF-α等细胞因子发挥效应功能.其中IL-21作为Th17细胞的一个自分泌调节凶子,在诱导Th17分化、抑制Th1、Treg功能方面发挥关键作用.而另一方面,近来发现,重要的T细胞生长因子IL-2在维持、促进Th1、Th2、Treg及CD8 T细胞功能活性的同时,却发挥着抑制Th17细胞分化的作用.Th1、Treg、Th17细胞的分化之间存在微妙的调节关系,TGF-β的水平、作用的时间决定着上述三群T细胞的分化结局.Th17细胞与Th1细胞均是自身免疫病及感染性疾病的重要效应细胞,二者的作用是否有时间、空间、功能方面的特异性?TGF-β如何调节两群效应细胞的分化方向及功能?以及Th17细胞在体内免疫平衡中的作用,是否可以通过Th17细胞诱导免疫耐受等,是人们急于回答的非常有意义的课题.     

Cooperation and Competition as a Function of Zygosity in 7- to 9-Year-Old Twins

A study of 31 monozygotic (MZ) and 24 dizygotic (DZ) Singapore twin pairs (aged 7.6 to 9.7 years) is reported. MZ and DZ twins differed in cooperative and competitive behaviors measured by within-pair reactions to payoff structures designed to elicit simultaneous cooperation (SCO) or reciprocal altruism (RA) on a marble-pull task. Reciprocation entailed turn-taking in rewards. DZ twins showed greater competition than MZ twins when competing for marbles in the RA condition, as predicted. Unexpectedly, however, MZ twins were markedly more competitive than DZ twins under the SCO condition, when success on the task always rewarded both twins. The competition arose over which end of the apparatus was to be used on a given trial. This interaction between condition and zygosity could not be related to differences in parents’ reported treatment of their children or zygosity beliefs, nor did it appear to be related to differences in factors such as time spent together and shared activities. An explanation in terms of uncertain or unstable dominance in MZ twinships is suggested.     

Adaptive Transformations of the Heart Rhythm Regulation and Structure of Behavioral Acts after Glycine Administration

The aim of this study was investigation of adaptive alterations in the structure of heart rhythm regulation, the functional levels of memory, and the dynamic characteristics of behavior after the administration of glycine. The heart rhythm variability, using standard statistical techniques of autocorrelation and spectral analysis, was analyzed. Nonsymbolic testing of the visual memory in three visual pattern (7 + 2) exposure modes was also assessed, where the number of correct and incorrect responses and temporal characteristics were calculated. Assessment of the functional state was conducted using dynamic characteristics of the behavioral act in stochastic and deterministic environments and involved measurement of the total response rate, its variance, and differential characteristics of decision making given repeated choices and during choice assessment after successful and unsuccessful trials. Healthy subjects 35–45 years old (7 males and 10 females) were tested before and after sublingual administration of glycine, 0.2 g two times a day, for three weeks. It was found that the sympathetic contribution to the heart rate regulation increased after the administration of glycine and was more pronounced in females. The rate of cognitive processing also significantly increased with an increased plasticity of prognostic self-regulation in all subjects and increased the sensitivity in a stochastic environment in females.     

pygo基因对心脏功能的调控及其研究进展

Wg/Wnt信号参与调控多种组织的发育,尤其在心脏发育和心脏衰老过程中发挥重要的作用。pygo作为Wnt信号途径的一个新成员,可能依赖于Wnt信号调控心脏发育,而最新发现pygo敲低品系引起的成体心脏功能缺陷与Wnt信号缺失在心脏中的表型具有显著性差异,表明pygo调控成体心脏功能不依赖于经典Wnt信号,可能存在新的调控机制。主要对pygo基因在调控心脏发育和心脏衰老中的功能以及在果蝇和哺乳动物中pygo基因调控心脏功能分子机制的研究进展进行了综述。虽然pygo不依赖经典Wnt信号在成体心脏中发挥作用,但显性负抑制TCF突变体引起严重的成体心脏生理功能缺陷,与pygo表型一致,暗示着pygo可能依赖与TCF类似因子相互作用发挥功能。其次,pygo能跨越TCF或Lgs直接与Wnt信号靶基因相互作用。此外,Pygo蛋白能与Lgs相互作用形成Pygo-BCL9/Lgs-H3K4me复合物调节Wnt信号靶基因,且甲基转移酶HMT核心组件WDR5与Pygo蛋白的相互作用能促进PHD结构域与H3K4的结合,表明pygo调节成体心脏功能与表观遗传学修饰也具有一定的相关性。     

The Effect of Biofeedback on Function in Patients with Heart Failure

Decreased HRV has been consistently associated with increased cardiac mortality and morbidity in HF patients. The aim of this study is to determine if a 6-week course of heart rate variability (HRV) biofeedback and breathing retraining could increase exercise tolerance, HRV, and quality of life in patients with New York Heart Association Class I-III heart failure (HF). Participants (N = 29) were randomly assigned to either the treatment group consisting of six sessions of breathing retraining, HRV biofeedback and daily practice, or the comparison group consisting of six sessions of quasi-false alpha-theta biofeedback and daily practice. Exercise tolerance, measured by the 6-min walk test (6MWT), HRV, measured by the standard deviation of normal of normal beats (SDNN), and quality of life, measured by the Minnesota Living with Congestive Heart Failure Questionnaire, were measured baseline (week 0), post (week 6), and follow-up (week 18). Cardiorespiratory biofeedback significantly increased exercise tolerance (p = .05) for the treatment group in the high (≥31%) left ventricular ejection fraction (LVEF) category between baseline and follow-up. Neither a significant difference in SDNN (p = .09) nor quality of life (p = .08), was found between baseline and follow-up. A combination of HRV biofeedback and breathing retraining may improve exercise tolerance in patients with HF with an LVEF of 31% or higher. Because exercise tolerance is considered a strong prognostic indicator, cardiorespiratory biofeedback has the potential to improve cardiac mortality and morbidity in HF patients.

Load Dependency of Postural Control - Kinematic and Neuromuscular Changes in Response to over and under Load Conditions

Introduction

Load variation is associated with changes in joint torque and compensatory reflex activation and thus, has a considerable impact on balance control. Previous studies dealing with over (OL) and under loading (UL) used water buoyancy or additional weight with the side effects of increased friction and inertia, resulting in substantially modified test paradigms. The purpose of this study was to identify gravity-induced load dependency of postural control in comparable experimental conditions and to determine the underlying neuromuscular mechanisms.

Methods

Balance performance was recorded under normal loading (NL, 1g), UL (0.16g; 0.38g) and OL (1.8g) in monopedal stance. Center of pressure (COP) displacement and frequency distribution (low 0.15-0.5Hz (LF), medium 0.5-2Hz (MF), high 2-6Hz (HF)) as well as ankle, knee and hip joint kinematics were assessed. Soleus spinal excitability was determined by H/M-recruitment curves (H/M-ratios).

Results

Compared to NL, OL caused an increase in ankle joint excursion, COP HF domain and H/M-ratio. Concomitantly, hip joint excursion and COP LF decreased. Compared to NL, UL caused modulations in the opposite direction: UL decreased ankle joint excursions, COP HF and H/M-ratio. Collaterally, hip joint excursion and COP LF increased. COP was augmented both in UL and in OL compared to NL.

Conclusion

Subjects achieved postural stability in OL and UL with greater difficulty compared to NL. Reduced postural control was accompanied by modified balance strategies and compensatory reflex activation. With increasing load, a shift from hip to ankle strategy was observed. Accompanying, COP frequency distribution shifted from LF to HF and spinal excitability was enhanced. It is suggested that in OL, augmented ankle joint torques are compensated by quick reflex-induced postural reactions in distal muscles. Contrarily, UL is associated with diminished joint torques and thus, postural equilibrium may be controlled by the proximal segments to adjust the center of gravity above the base of support.     

Cardiac Rhythm Regulation in Children during the Initial Period of School Education under Conditions of the North

Cardiac rhythm parameters recorded in healthy children during the initial weeks of schoolwork immediately after the transition from kindergarten to the first grade of the elementary school or from the elementary school to the fifth grade of the middle school showed that their regulatory systems were stressed to different degrees, reflecting different costs of adaptation to environmental conditions. The most pronounced changes in these parameters were observed in the first graders: because of more significant stress (sometimes, overstress) of their regulatory mechanisms, in 70% of these children complete adaptation to new living conditions was associated with greater physiological costs. In the fifth graders, a similar situation was observed only in 25% of the children examined. The less pronounced physiological changes observed in 30% of the first graders and in 75% of the fifth graders can be related to the more mature state of their cardiac regulatory mechanisms, as well as to their greater adaptability to environmental conditions during the period examined.     

Characteristics of Autonomic Regulation of the Heart Function in Musicians Playing Wind Instruments

Neurophysiology - We compared measures of the sympatho-vagal balance in heart regulation and cardiovagal baroreflex sensitivity (BRS) between musicians playing wind instruments (n = 23) and...     

生理节律与日常活动对人体疲劳程度的影响

目的:研究生理节律和日常活动分别对人体疲劳程度的影响大小。方法:选取某校7名大学生志愿者,在军训期间对每日军训科目严格限制条件下进行该实验,以闪光临界融合频率、心率变异性、反应时、静态姿势图TLX-NASA量表评分作为指标,对每天分别在训练前和训练后疲劳程度的大小进行测量,以这些指标描述训练前后的疲劳程度。结果:反应时降低(0.60±0.09)、反应正确率提高(0.97±0.03);闪光临界光融合频率升高(40.84±2.14);心率变异性TP(3076.60±382.08)降低、心率变异性SDNN(55.28±16.85)降低;静态姿势图晃动减少,中低频率段(0.15±0.01)、前后方向重心变位(7.92±0.63),TLX-NASA量表评分降低(30.47±10.23)。以上差异均具有统计学意义(P<0.05)。结论:生理节律相对于日常活动对机体的疲劳状态有更大的影响。     

心衰进程中非编码RNA对线粒体功能的调控作用

心衰长久以来一直缺少有效治疗方法,给社会造成了巨大的经济和民生负担,新诊断标志物的确认和治疗方法的研发十分迫切。线粒体功能障碍与心衰发生和发展密切相关,以线粒体为基础的能量供应紊乱、钙失衡、氧化应激和细胞死亡在心衰的发展中起着重要作用,但线粒体调控的具体机制还不十分清楚。非编码RNA被证实在表观调控、转录后修饰、翻译调节等多方面发挥重要调控作用。研究表明,包括miRNA、lncRNA、circRNA在内的大量非编码RNA在心脏发育和心脏疾病发展过程中存在差异表达,并在线粒体蛋白稳态、氧化磷酸化、氧化应激、凋亡与自噬等调控中发挥了重要作用,进而影响心衰等心脏疾病的发生发展,但其详细机制尚未完全阐明。本文就近年心衰发生和发展过程中非编码RNA调控线粒体功能机制的相关研究进行综述,梳理了近年来非编码RNA在调节线粒体结构与功能进而影响心衰发展方面的研究进展,以期为心衰研究与治疗提供新的思路和靶点。     

低密度脂蛋白受体相关蛋白2结合蛋白在心脏特异转基因小鼠中引起的心脏功能代偿

目的建立心脏特异表达的低密度脂蛋白受体相关蛋白2结合蛋白(Lrp2bp)转基因小鼠,研究该基因在心肌病发病中的作用。方法克隆鼠源Lrp2bp基因入α-MHC启动子下游,构建a-MHC-Lrp2bp表达载体,显微注射法建立Lrp2bp转基因小鼠。PCR鉴定转基因首建鼠的基因型。Westernblotting鉴定Lrp2bp在心脏中的表达,心脏超声检测转基因鼠及野生型小鼠心脏结构和功能,透射电镜观察心肌细胞的超微结构改变。结果得到了4个Lrp2bp转基因品系,其中3个品系心脏Lrp2bp蛋白表达量与同龄野生型鼠相比明显增加。1M龄转基因小鼠与同窝阴性对照小鼠相比,心壁变厚,心腔变大,射血分数和短轴缩短率下降。结论心脏特异表达的Lrp2bp基因能引起心肌肥厚表型,可能是参与心肌代偿性肥厚的基因之一。     

Effect of Resistive Load on the Inspiratory Work and Power of Breathing during Exertion

The resistive work of breathing against an external load during inspiration (WR_I) was measured at the mouth, during sub-maximal exercise in healthy participants. This measure (which excludes the elastic work component) allows the relationship between resistive work and power, ventilation and exercise modality to be explored. A total of 45 adult participants with healthy lung function took part in a series of exercise protocols, in which the relationship between WR_I, power of breathing, PR_I and minute ventilation, were assessed during rest, while treadmill walking or ergometer cycling, over a range of exercise intensities (up to 150 Watts) and ventilation rates (up to 48 L min⁻¹) with applied constant resistive loads of 0.75 and 1.5 kPa.L.sec⁻¹. Resting WR_I was 0.12 JL⁻¹ and PR_I was 0.9 W. At each resistive load, independent of the breathing pattern or exercise mode, the WR_I increased in a linear fashion at 20 mJ per litre of , while PR_I increased exponentially. With increasing resistive load the work and power at any given increased exponentially. Calculation of the power to work ratio during loaded breathing suggests that loads above 1.5 kPa.L.sec⁻¹ make the work of resistive breathing become inhibitive at even a moderate (>30 L sec⁻¹). The relationship between work done and power generated while breathing against resistive loads is independent of the exercise mode (cycling or walking) and that ventilation is limited by the work required to breathe, rather than an inability to maintain or generate power.     

Autonomic Regulation of Heart Rate and Distinctive Features of Oculomotor Activity in Eight- to Nine-Year-Old Boys and Girls during the Reading of Texts of Different Complexities

Distinctive features of autonomic regulation of the heart rate and spatiotemporal parameters of eye movements during the reading of texts of different complexities levels from a computer screen have been analyzed in girls and boys eight to nine years of age. Sex-related differences in heart rate variability (HRV) pattern were already observed in the resting state, since parasympathetic effects were stronger in boys than in girls. Parasympathetic activity decreased in boys who were reading texts of different complexities. The most pronounced decrease was observed during the reading of the first (simple) text. The changes in girls were mostly due to an increase in sympathetic activity and were less pronounced than in boys. Oculomotor activity analysis revealed differences in reading process strategy: reading was more fragmented (discrete) in the girls and more integrated in the boys. However, reading skills were not fully developed in children of eight to nine years of age, since “syllabized” reading was observed in girls and boys alike.