大鼠心率变异性频谱中高频成分的中枢机理分析

本文探讨心率变异性（ＨＲＶ）频谱中高频成分的中枢机理。对正常ＳＤ大量给予不同频率的人工通气并电刺激延髓疑核,观察ＨＲＶ频谱的改变,记录与呼吸节律同步的延髓头端腹外侧区（ｒＶＬＭ）及其周围区神经元细胞外单位放电,对ＨＲＶ和放电变异性进行相干函数分析。结果显示：（１）ＨＲＶ的高频成分的中心频率随着人工通气频率的增加而增加,呈高度线性相关,（ｒ＝０．８３,Ｐ〈０．０００１）;（２）对ｒＶＬＭ及其周围区与     

延髓头端腹外侧区神经元电活动与心血管活动相干性的研究

本文分析了大鼠延头端腹外侧区（ＲＶＬＭ）神经元单位活动与心血管活动的相干性,观察了ＲＶＬＭ区神经元电 对电刺激中脑防御反应区的诱发反应,以及对压力感受性反射的反应,并用ＦＦＴ对ＲＶＬＭ区神经元自发单位放电和血压波进行频域的相干性分析,以判断是具有心节律。还分析了ＲＶＬＭ区单位放电变异性与心率变异性的相干性。结果显示：ＲＶＬＭ区大多数神经元对电刺激中脑防御反应区呈兴奋反应（６７％）,７０％神经元放电     

健康人不同年龄段HRV频谱分析及进食,心算的影响

应用上医大生理教研室研制的“心率变异性频谱分析仪”,以Ｒ－Ｒ间距总变异性（ＴＶ）、低频成分（ＬＦ）、高频成分（ＨＦ）以及ＬＰ／ＨＦ比值为指标,对健康人不同年龄段、午饭前后及安静与心算时的心率变异性（ＨＲＶ）进行频谱分析,结果表明：健康女性６０岁以上,男性５０岁以上各年龄段ＴＶ较低龄段显著降低,女性３０岁以上各年龄段及男性５０－６０岁ＬＦ、女性２０岁以上及男性２１－５０岁各年龄段ＨＦ均较低龄段升高显著,女性２１－３０岁较１－１０岁ＬＦ／ＨＦ降低显著;午饭后ＴＶ均较饭前显著降低,心算时ＬＦ显著升高,ＨＦ显著降低,≥４０岁组心算时ＬＦ／ＨＦ显著升高。结果提示：健康人高龄段调控心脏的自主神经整合功能显著降低,健康人的交感、迷走神经活动在不同年龄段有着不同的变化;健康成人午饭后自主神经整合功能显著降低;心算时交感神经活动显著增强,迷走神经活动显著降低,≥４０岁组心交感神经活动增强尤为显著。     

同心圆变量分析法在整体低温生理研究中的应用

为了探寻适合于整体研究特点——多系统、多功能及大量生理信息的分析研究方法,我们曾在浸泡性体温过低动物实验中,利用微机等技术手段获取了大量生理参数,并用同心圆变量分析法及相关分析进行处理,揭示了进行性体温过低症某些较复杂的病理生理改变。本研究以该动物模型为例,侧重从方法学角度介绍同心圆变量分析法及其在整体低温生理研究中的应用。 1 材料和方法 健康成年狗22只,雄性,体重13～20kg,戊巴     

肌肉损伤和肌肉生理

本回顾我国运动生理学的发展进程,肌肉生理的现状及其损伤临床治疗的一些问题。     

疱疹病毒对抗病毒药物抗性的回顾

本文就单纯疱疹病毒（ＨＳＶ）、水痘带状疱疹病毒（ＶＺＶ）、人巨细胞病毒（ＨＣＭＶ）、ＥＢ病毒（ＥＢＶ）等疱疹病毒的抗病毒药物,产生抗性的机理和抗病毒治疗的策略等方面进行了回顾。     

持续性病毒感染免疫应答的群体动力学

本文以数学模式来探讨抗病毒免疫应答、病毒含量以及病毒变异性间的关系。由数学模式表明的结果并与人血病病毒Ｉ型（ＨＴＬＶ－Ｉ）和人类免疫缺陷病毒Ｉ型（ＨＩＶ－１）感染中杀伤性Ｔ细胞反应和病毒变异性研究的研究资料进行比较,获得较为一致的结果。     

迷走神经兴奋对HRV的影响及其机制的初步分析

实验在氯醛糖加氨基甲酸乙酯麻醉的新西兰兔上进行。记录血压、心率、心电图和心率变异性（ＨＲＶ）频谱分析。电刺激减压神经（ＤＮ）,疑核（ＮＡ）和右侧迷走神经（ＲＶ）外周端,均引起心率和血压下降（Ｐ＜０．００１）,总变异性（ＴＶ）、低频成分（ＬＦ）、高频成分（ＨＦ）、ＬＦ／ＨＦ比值（ＬＦ／ＨＦ）和极低频成分（ＶＬＦ）增大（Ｐ＜０．０５－０．００１）。静脉注射阿托品可使上述反应显著减小（Ｐ＜０．０５－０．０１）,而静脉注射心得安仅可阻断ＤＮ和ＮＡ所致ＬＦ的增大（Ｐ＜０．０５）。以上结果表明：迷走神经是ＨＲＶ的主要调节者之一;ＨＦ由迷走神经单独介导;ＬＦ受迷走神经和交感神经共同调制;迷走神经参与ＶＬＦ波的形成     

物种多样性与生态系统功能时间变异性的关系研究进展

近年来物种多样性的急剧丧失使得物种多样性与生态系统功能的时间变异性的关系及其机制问题的研究成为了生态学研究的一个热点。综述了物种多样性与群落集合性质变异性以及种群性质变异性的关系及其机制的最新研究成果：1、理论上探讨造成物种多样性与群落集合性质变异性负相关关系的机制包括：抽样效应、资源利用分化假说、统计平均效应、保险假说、种群变异性的均匀度效应等;但实验研究对理论预期的支持并不是普遍的;2．多样性与种群变异性之间的关系主要依赖于均值-方差尺度系数Z;理论上大部分自然群落是种群变异性应该随着多样性的增加而增加;但有研究表明：在变动环境中多样性对单个组分物种的种群水平有稳定性作用;而经验研究并不能得出多样性对种群变异性效应的清晰模式。讨论了目前的理论和实验研究中存在的和今后研究中需要认真思考的问题。     

青藏高原小型哺乳动物的生理生态学研究：从个体到生态系统

本文回顾了青藏高原小型哺乳动物生理生态学研究取得的主要成就,包括能量代谢特征与环境适应性、适应性产热与体温调节、能量平衡与体重调节、生理极限值和种群能流估算等,总结了近年一些新兴领域的最新进展,包括双标记水方法测定能量消耗、肠道菌群的功能、地理生理学、种群生理学、植物次生代谢产物及其生理功能等。有些工作引领了中国动物生理生态学的发展,如生态能量学、适应性产热和生理适应等。本文对未来需要发展的领域和深入方面提出了建议,希望能建立青藏高原小型哺乳动物生理生态学学科体系。     

Possible links between phenotypic variability,habitats and connectivity in the killifish Aphaniops stoliczkanus in Northeast Oman

There is a significant gap in our knowledge of the intraspecific morphological variability in freshwater fish, although such data are crucial for understanding species diversity. Here we use the killifish Aphaniops stoliczkanus (Day, 1872; Aphaniidae: Cyprinodontiformes), which is a widespread but poorly known freshwater species in the Middle East, to investigate variability in morphological traits within and between its populations. As otolith morphology is known to evolve on ecological timescales and can signal the presence of cryptic lineages, a special focus lies on otolith variability. Based on samples from six populations in northern Oman, we found that variation in pigmentation, disparities in body shape and otolith variability can be associated with distinctive environmental conditions. The unique otolith shape of A. stoliczkanus from a hot sulphuric spring (Nakhal) suggests that a cryptic lineage may have emerged there. Our new data can serve as a benchmark for future studies on the diversity of Aphaniops and other Aphaniidae and help to clarify whether cryptic diversity is present in some lineages. Moreover, our data can serve as an actualistic model for studies on fossil fishes, in which morphological characters provide the only accessible data source for taxonomic and phylogenetic interpretations.     

Dynamic changes in display architecture and function across environments revealed by a systems approach to animal communication*

Animal communication is often structurally complex and dynamic, with signaler and receiver behavior varying in response to multiple environmental factors. To date, studies assessing signal dynamics have mostly focused on the relationships between select signaling traits and receiver responses in a single environment. We use the wolf spider Schizocosa floridana to explore the relationships between courtship display form and function across two social contexts (female presence vs absence) and two light environments (light vs dark). We use traditional analytical methods to determine predictors of copulation success (i.e., signal function) and examine these predictors in a structural context by overlaying them on signal phenotype networks (Wilkins et al. 2015). This allows us to explore system design principles (degeneracy, redundancy, pluripotentiality), providing insight into hypotheses regarding complex signal evolution. We found that both social context and light environment affect courtship structure, although the predictors of mating success remain similar across light environments, suggesting system degeneracy. Contrastingly, the same display traits may serve different functions across social environments, suggesting pluripotentiality. Ultimately, our network approach uncovers a complexity in display structure and function that is missed by functional analyses alone, highlighting the importance of systems‐based methodologies for understanding the dynamic nature of complex signals.     

Virological surveillance,molecular phylogeny,and evolutionary dynamics of hepatitis C virus subtypes 1a and 4a isolates in patients from Saudi Arabia

Hepatitis C virus (HCV) subtypes are pre-requisite to predict endemicity, epidemiology, clinical pathogenesis, diagnosis, and treatment of chronic hepatitis C infection. HCV genotypes 4 and 1 are the most prevalent in Saudi Arabia, however; less consensus data exist on circulating HCV subtypes in infected individuals. This study was aimed to demonstrate the virological surveillance, phylogenetic analysis, and evolutionary relationship of HCV genotypes 4 and 1 subtypes in the Saudi population with the rest of the world. Fifty-five clinical specimens from different parts of the country were analyzed based on 5′ untranslated region (5′ UTR) amplification, direct sequencing, and for molecular evolutionary genetic analysis. Pair-wise comparison and multiple sequence alignment were performed to determine the nucleotide conservation, nucleotide variation, and positional mutations within the sequenced isolates. The evolutionary relationship of sequenced HCV isolates with referenced HCV strains from the rest of the world was established by computing pairwise genetic distances and generating phylogenetic trees. Twelve new sequences were submitted to GenBank, NCBI database. The results revealed that HCV subtype 4a is more prevalent preceded by 1a in the Saudi population. Molecular phylogeny predicts the descendants’ relationship of subtype 4a isolates very close to Egyptian prototype HCV strains, while 1a isolates were homogeneous and clustering to the European and North American genetic lineages. The implications of this study highlight the importance of HCV subtyping as an indispensable tool to monitor the distribution of viral strains, to determine the risk factors of infection prevalence, and to investigate clinical differences of treatment outcomes among intergenotypic and intragenotypic isolates in the treated population.     

Assessing phylogenetic signal with measurement error: a comparison of mantel tests, blomberg et Al.'s k, and phylogenetic distograms

In macroevolutionary studies, different approaches are commonly used to measure phylogenetic signal-the tendency of related taxa to resemble one another-including the K statistic and the Mantel test. The latter was recently criticized for lacking statistical power. Using new simulations, we show that the power of the Mantel test depends on the metrics used to define trait distances and phylogenetic distances between species. Increasing power is obtained by lowering variance and increasing negative skewness in interspecific distances, as obtained using Euclidean trait distances and the complement of Abouheif proximity as a phylogenetic distance. We show realistic situations involving "measurement error" due to intraspecific variability where the Mantel test is more powerful to detect a phylogenetic signal than a permutation test based on the K statistic. We highlight limitations of the K-statistic (univariate measure) and show that its application should take into account measurement errors using repeated measures per species to avoid estimation bias. Finally, we argue that phylogenetic distograms representing Euclidean trait distance as a function of the square root of patristic distance provide an insightful representation of the phylogenetic signal that can be used to assess both the impact of measurement error and the departure from a Brownian evolution model.     

Tutorial. Surface EMG detection,conditioning and pre-processing: Best practices

This tutorial is aimed primarily to non-engineers, using or planning to use surface electromyography (sEMG) as an assessment tool for muscle evaluation in the prevention, monitoring, assessment and rehabilitation fields. The main purpose is to explain basic concepts related to: (a) signal detection (electrodes, electrode–skin interface, noise, ECG and power line interference), (b) basic signal properties, such as amplitude and bandwidth, (c) parameters of the front-end amplifier (input impedance, noise, CMRR, bandwidth, etc.), (d) techniques for interference and artifact reduction, (e) signal filtering, (f) sampling and (g) A/D conversion, These concepts are addressed and discussed, with examples.The second purpose is to outline best practices and provide general guidelines for proper signal detection, conditioning and A/D conversion, aimed to clinical operators and biomedical engineers. Issues related to the sEMG origin and to electrode size, interelectrode distance and location, have been discussed in a previous tutorial. Issues related to signal processing for information extraction will be discussed in a subsequent tutorial.     

Techniques of EMG signal analysis: detection, processing, classification and applications

Electromyography (EMG) signals can be used for clinical/biomedical applications, Evolvable Hardware Chip (EHW) development, and modern human computer interaction. EMG signals acquired from muscles require advanced methods for detection, decomposition, processing, and classification. The purpose of this paper is to illustrate the various methodologies and algorithms for EMG signal analysis to provide efficient and effective ways of understanding the signal and its nature. We further point up some of the hardware implementations using EMG focusing on applications related to prosthetic hand control, grasp recognition, and human computer interaction. A comparison study is also given to show performance of various EMG signal analysis methods. This paper provides researchers a good understanding of EMG signal and its analysis procedures. This knowledge will help them develop more powerful, flexible, and efficient applications.     

The influence of digital filter type,amplitude normalisation method,and co-contraction algorithm on clinically relevant surface electromyography data during clinical movement assessments

There is a large and growing body of surface electromyography (sEMG) research using laboratory-specific signal processing procedures (i.e., digital filter type and amplitude normalisation protocols) and data analyses methods (i.e., co-contraction algorithms) to acquire practically meaningful information from these data. As a result, the ability to compare sEMG results between studies is, and continues to be challenging. The aim of this study was to determine if digital filter type, amplitude normalisation method, and co-contraction algorithm could influence the practical or clinical interpretation of processed sEMG data. Sixteen elite female athletes were recruited. During data collection, sEMG data was recorded from nine lower limb muscles while completing a series of calibration and clinical movement assessment trials (running and sidestepping). Three analyses were conducted: (1) signal processing with two different digital filter types (Butterworth or critically damped), (2) three amplitude normalisation methods, and (3) three co-contraction ratio algorithms. Results showed the choice of digital filter did not influence the clinical interpretation of sEMG; however, choice of amplitude normalisation method and co-contraction algorithm did influence the clinical interpretation of the running and sidestepping task. Care is recommended when choosing amplitude normalisation method and co-contraction algorithms if researchers/clinicians are interested in comparing sEMG data between studies.     

Reactive oxygen species, cell signaling, and cell injury

Oxidative stress has traditionally been viewed as a stochastic process of cell damage resulting from aerobic metabolism, and antioxidants have been viewed simply as free radical scavengers. Only recently has it been recognized that reactive oxygen species (ROS) are widely used as second messengers to propagate proinflammatory or growth-stimulatory signals. With this knowledge has come the corollary realization that oxidative stress and chronic inflammation are related, perhaps inseparable phenomena. New pharmacological strategies aimed at supplementing antioxidant defense systems while antagonizing redox-sensitive signal transduction may allow improved clinical management of chronic inflammatory or degenerative conditions, including Alzheimer's disease. Introduction of antioxidant therapies into mainstream medicine is possible and promising, but will require significant advances in basic cell biology, pharmacology, and clinical bioanalysis.