兔跑跳训练过程中后肢小腿生物电阻抗变化研究

目的:用生物电阻抗的方法监控兔训练过程中后肢小腿阻抗的变化,研究在正常生理状态下运动引起的生物组织电阻抗变化规律.方法:将8只新西兰大白兔随机分为两组,训练组和对照组:训练组按照训练计划严格接受跑跳训练;对照组正常饲养,不进行任何训练.在该过程中不断重复检测兔子后肢小腿生物电阻抗数据,第27天后结束训练.结果:生物电阻抗在对照组中的变化没有统计差异,而训练组中生物电阻抗的变化有一定规律和统计学差异.结论:在兔子正常生理情况下,运动可以改变兔后肢小腿的生物电阻抗值,这种改变是有规律的,生物电阻抗技术可以被用来监控生物组织正常生理状况下的状态.     

血管新生的分子机制与相关疾病

正血管新生指从已存在的血管上生长出新的毛细血管的过程~([1])。该过程十分复杂,依赖血管内皮细胞、成纤维细胞、巨噬细胞和细胞外基质的相互作用,并受促血管新生分子和抗血管新生分子协同调控。生理条件下,促血管新生分子和抗血管新生分子保持动态平衡;一旦平衡被打破,机体就会出现多种疾病,如肿瘤、多种眼科疾病、帕金森病(Parkinson’s disease,PD)和阿尔茨海默症(Alzheimer’s di-     

内皮祖细胞的动员、归巢和分化

内皮祖细胞是内皮细胞的前体细胞 ,在某些生理、病理状态下可随血流至相应组织 ,分化为内皮细胞 ,并进一步形成血管。内皮祖细胞不仅参与胚胎发育的血管发生 ,而且在成人机体的血管新生中起重要的作用。研究内皮祖细胞的生物学特性、动员、归巢及分化机制将为临床治疗缺血性疾病、创伤修复及抑制肿瘤生长提供理论依据。     

心电图数字化诊断管理系统临床应用价值的探讨

心血管病随着人们预期寿命延长将会增多,因此有利于心血管病诊断的科学技术必然是目前医务工作者最关注的事。在各种心电信息检测技术中,心电图仍然是描记分析心脏电活动最重要方法。因为心电图波形简结,尤其它是一项价廉且无创伤性检查,迄今为止没有一项检查能替代心电图检查。但由于心电学是直接以生物电为基础来表明心脏生物电活动现象,与之相关的是心肌电生理特性如自律性、应激性和传导性,其内涵高深而不显露。因此伴随着心电学的深入研究与心电信息“高速公路”的开通,尤其是多媒体和传真以及被人称为“第四媒体”的网络技术和心血管…     

血管生成抑制蛋白vasohibin的研究进展

血管新生参与机体重要的生理和病理过程。Vasohibin是新近发现的调节血管生成的内皮源性负反馈调节因子,对抑制血管生成起重要作用。Vasohibin因参与肿瘤﹑视网膜疾病及类风湿性关节炎等血管新生异常疾病的发生发展而备受关注,相关研究可望为探索这些疾病的发生机制以及寻找新的治疗措施奠定基础。     

诱发电位地形图

诱发电位地形图是一种特殊的脑电地形图。一般所指的脑电地形图系患在闭目安静的情况下，避免了一切外界的刺激状态下收集的脑生物电信息而形成的脑电空间电位活动的地形图。诱发电位地形图是在给予特定条件的外加刺激(声，光，电)所收到的反应大脑在这种特定外来刺激下的空间电位变化称之为诱发电位脑电地形图。     

细胞自噬在血管新生中作用的研究进展

自噬(autophagy)是细胞利用溶酶体降解自身受损的细胞器和大分子物质的过程,在稳定细胞内环境中发挥着重要作用。在血管新生的病理生理过程中,细胞自噬作用持续存在。从自噬的角度探索血管新生的发生发展进程,能够为临床治疗血管相关疾病提供新的思路。     

缺血性血管疾病的治疗性血管重建

缺血性血管疾病包括冠心病和外周血管闭塞性疾病已成为发达国家及许多发展中国家的主要疾病之一。血管重建 (即血管新生、血管生成及动脉生成 )是机体在血管闭塞状态下的病理生理性代偿反应。以改善缺血为目的 ,应用促血管因子、基因治疗和血管祖细胞补充治疗已成为当前缺血性血管疾病治疗的研究热点。     

血管新生在肿瘤侵袭和器官纤维化中作用的最新认识

微血管密度与肿瘤侵袭力以及器官纤维化程度密不可分,血管新生是这两类疾病的共同靶点。然而,传统抗血管新生疗法由于肿瘤耐药性等原因而疗效有限,而以促血管新生的目标的抗纤维化疗法也因为伴随炎性反应、血管通透性改变等原因陷入瓶颈。本文探讨肿瘤和器官纤维化的在血管新生方面的内在关联。     

脉冲电刺激对血管内皮细胞与其祖细胞黏附的影响

为探索脉冲电刺激下血管内皮细胞与内皮祖细胞(EPC)之间黏附强度的改变,诱导培养外周血EPC,荧光标记后与单层血管内皮细胞共培养,固定电压和频率为5 V和5 Hz,选择1、3、6、9 ms的脉宽对其进行干预,持续刺激24 h后检测贴壁EPC的荧光强度,以荧光比率衡量。结果显示,与对照组相比,3 ms刺激组荧光比率即显著增高,随着脉宽延长,6 ms组达到最大值,但9 ms刺激组却显著下降,提示适宜脉冲电刺激有利于血管内皮细胞与EPC之间的黏附,为电刺激促进血管新生的研究提供新的理论依据。     

Bone bioelectricity: what have we learned in the past 160 years?

The direct relationship between bone strain and electric fields has spurred continual interest in the field of bioelectricity over the past 160 years. It has been reported that stress-generated potentials alter cell proliferation and extracellular matrix secretion. The observation that endogenous electrical signals facilitate osteoinduction has lead to high production of electrical stimulation devices to fix bone defects. Despite the reported 100,000 nonunions healed as of 1990 with electrical stimulation, skepticism due to lack of homogeneity with trial design and dosage still exists within the scientific community. It is the purpose of this review to assess the bioelectric phenomenon of bone as it applies to piezoelectricity, fracture healing, and overall changes in bone metabolism which occur with controlled electrical stimulation.     

Hypothalamic modulation of energy expenditure

The acute effects of electrical stimulation of the hypothalamus on energy expenditure as measured by indirect calorimetry were investigated in 20 unanaesthetized rats. Thirty sec of stimulation increased both O2 consumption and respiratory quotient (R.Q.). The largest magnitude hypermetabolic response (39% mean peak increase in O2 consumption) was produced by stimulation of the ventromedial hypothalamic nucleus. Stimulation of the lateral hypothalamus produced hypermetabolic effects similar to but smaller than those produced by medial stimulation. A number of considerations suggest that the hypermetabolism is not secondary to changes in motor activity, carbohydrate utilization or blood glucose levels. Consequently, these data suggest that the hypothalamus modulates energy expenditure through changes in non-shivering thermogenesis. These metabolic changes may modulate the effects of various hypothalamic manipulations on body weight.     

Eye movements in the cat evoked by electrical stimulation of the outer geniculate body

New data were obtained in experiments with unanesthetized animals showing that electrical stimulation of the structures of the outer geniculate body of the cat elicits goal-directed eye movements. Relationships were found between eye-movement amplitude and direction and the position of the eye at the instant of stimulation, as well as the position of the stimulating electrodes in the outer geniculate body. A scheme is proposed for the multilevel interaction of the visual and oculomotor systems during their functioning, and a possible relation is discussed between the described phenomenon and the mechanisms responsible for the foveation of objects during their recognition.Translated from Fiziologicheskii Zhurnal SSSR imeni I. M. Sechenova, Vol. 69, No. 2, pp. 167–175, February, 1983.     

Effect of experimentally induced generalized seizures on the wakefulness-sleep cycle

The effect of experimentally induced generalized seizures on the relations between the various phases of sleep in the wakefulness-sleep cycle was studied in cats with chronically implanted electrodes. After generalized convulsions induced by electrical stimulation of the dorsal hippocampus, unlike those of amygdalar origin, clearly defined changes were observed in the structure of the wakefulness-sleep cycle. In the postseizure period, with increasing wakefulness sharp depression of paradoxical sleep takes place. However, in slow wave sleep only slight changes were observed. Instead of a rebound phenomenon, paradoxical sleep was sharply induced in cats after preliminary deprivation of paradoxical sleep as a result of generalized seizures induced by electrical stimulation of the neocortex. Nonspecific hyperactivation of the brain, in the form of epileptiform discharges, thus has a particularly marked effect on the structure of paradoxical sleep.Translated from Fiziologicheskii Zhurnal SSSR imeni I. M. Sechenova, Vol. 63, No. 5, pp. 617–625, May, 1977.     

The effect of electrical stimulation of the hypothalamus on continuously-monitored blood glucose levels

The effects of hypothalamic stimulation on blood glucose levels were investigated in unanaesthetised rats with intracardiac catheters directly connected to a continuous glucose analyzer. Thirty sec of low level electrical stimulation produced hyperglycemia at 23 of the 34 sites stimulated. At the remaining 11 sites the electrical stimulation produced no changes in blood glucose levels. The hyperglycemia could be dissociated from the changes in motor activity produced by the stimulation. The highest probability of producing hyperglycemia was found at ventro-lateral sites although hyperglycemia was also observed after stimulation of dorsal and medial sites. Apart from this medio-lateral difference in the density of sites at which stimulation produced hyperglycemia, the effects were not well differentiated anatomically. In addition, in terms of latency, peak magnitude and duration of the hyperglycemia, stimulation of the various hypothalamic subdivisions appeared to be functionally equivalent. Thus with respect to hypothalamic involvement in the maintenance of blood glucose levels the present stimulation analysis suggests a medio-lateral functional similarity which is very different from the medio-lateral reciprocity of lesion effects on ingestive behaviour and body weight.     

Effects of thalamic high-frequency electrical stimulation on whisker-evoked cortical adaptation

Activity in thalamocortical circuits depends strongly on immediate past experience. When the successive activity is attenuated on short timescales, this phenomenon is known as adaptation. Adaptive processes may be effectively initiated by ongoing exposure to sensory stimuli and/or direct electrical stimulation of neural tissue. Ongoing high-frequency electrical stimulation is increasingly employed as a treatment for a variety of neurological disorders. Neural stimulation with similar parameters to therapeutic electrical stimulation may modulate the way in which cortical neurons respond and adapt to sensory stimuli. Here, we studied the effects of high-frequency stimulation of the somatosensory thalamus on the transmission of sensory signals in thalamocortical circuits. We examined how whisker-evoked sensory inputs in layer IV cortical barrels are affected by concurrent 100 Hz thalamic electrical stimulation and how the latter modulates sensory-evoked adaptation. Even in the presence of ongoing thalamic stimulation, sensory transmission in thalamocortical circuits is maintained. However, cortical responses to whisker deflections are reduced in an intensity-dependent fashion and can be nearly abolished with high intensity currents. The electrical stimulation-induced reduction in cortical responsiveness likely reflects engagement of circuit mechanisms that normally produce sensory adaptation.     

Long-term fluctuation of cerebral electrical activity as related to coagulation of the connections between hypothalamus and hypophysis

Summary Daily electrical stimulation of one of the regions of the hypothalamus caused fluctuations of electrical activity, i.e., rhythmic changes of high-amplitude oscillations of augmented frequency and low-amplitude oscillations of a lower frequency to develop in the stimulated center and in some other regions of the brain. Each period lasted for several tens of minutes. The waves were found to continue for several hours after stimulation, and could be subdivided into two stages. Coagulation of the hypophysis and infundibulum not only failed to prevent the development of the fluctuations but even augmented them. A restricted coagulation of the tract between the supra-optic region and the hypophysis on one side caused an increase in the fluctuations in the dorso-medial thalamic nucleus. Chemical transmitters appearing in the hypothalamus may therefore be associated with the phenomenon.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 55, No. 2, pp. 7–13, February, 1963Presented by Academician V. N. Chernigovskii     

Methods to Differentiate Electrically Induced Afferent and Sympathetic G Unit Responses in Human Cutaneous Nerves

C unit responses to intradermal electrical stimulation were recorded with tungsten micro-electrodes inserted percutaneously into intact human cutaneous nerves. An increase in discharge frequency was associated with a decrease in conduction velocity in unmyelinated fibres, and this phenomenon was used to identify afferent C units which responded to both electrical and natural stimuli in the skin. Antidromic impulses in efferent, sympathetic fibres were also elicited by electrical stimulation in the skin as judged by latency changes or signs of collisions in the C responses associated with activity in sympathetic fibres. In this way, conduction velocities in distal segments of both afferent and sympathetic C fibres can be estimated. Furthermore, the possibility to differentiate afferent and sympathetic C units is of obvious importance for the study of their respective discharge characteristics and in psychophysiological studies in alert man.     

水疗与电刺激联合防治大鼠失用性骨质疏松

背景：电刺激和水疗均对失用性骨质疏松有治疗作用,二者联合应用未见报道。 目的：观察水疗与电刺激联合作用对失用性骨质疏松模型大鼠生物力学的影响。 方法：采用切断坐骨神经和股神经的方法制备SD大鼠失用性骨质疏松模型。伤口愈合后采用电刺激、水疗及二者联合干预8周,观察大鼠体质量及股骨生物力学指标的变化。 结果与结论：去神经后失用性骨质疏松大鼠体质量显著增加,股骨的材料力学和结构力学指标上均出现明显异常,经电刺激和(或)水疗干预后失用性骨质疏松大鼠的体质量有所下降,股骨的材料力学和结构力学指标有所改善,尤其是电刺激和水疗联合应用,可明显改善失用性骨质疏松大鼠股骨的最大载荷、破断载荷、弹性模量和极限强度。     

Role of the rostral ventrolateral medulla (RVLM) in the patterning of vestibular system influences on sympathetic nervous system outflow to the upper and lower body

Research on animal models as well as human subjects has demonstrated that the vestibular system contributes to regulating the distribution of blood in the body through effects on the sympathetic nervous system. Elimination of vestibular inputs results in increased blood flow to the hindlimbs during vestibular stimulation, because it attenuates the increase in vascular resistance that ordinarily occurs in the lower body during head-up tilts. Additionally, the changes in vascular resistance produced by vestibular stimulation differ between body regions. Electrical stimulation of vestibular afferents produces an inhibition of most hindlimb vasoconstrictor fibers and a decrease in hindlimb vascular resistance, but an initial excitation of most upper body vasoconstrictor fibers accompanied by an increase in upper body vascular resistance. The present study tested the hypothesis that neurons in the principal vasomotor region of the brainstem, the rostral ventrolateral medulla (RVLM), whose projections extended past the T10 segment, to spinal levels containing sympathetic preganglionic neurons regulating lower body blood flow, respond differently to electrical stimulation of the vestibular nerve than RVLM neurons whose axons terminate rostral to T10. Contrary to our hypothesis, the majority of RVLM neurons were excited by vestibular stimulation, despite their level of projection in the spinal cord. These findings indicate that the RVLM is not solely responsible for establishing the patterning of vestibular-sympathetic responses. This patterning apparently requires the integration by spinal circuitry of labyrinthine signals transmitted from the brainstem, likely from regions in addition to the RVLM.