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111.
Patrick Feiereisen Jacques Duchateau K. Hainaut 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1997,114(1):117-123
The recruitment order of motor units (MU) was compared during voluntary and electrically induced contractions. With the use
of spike-triggered averaging, a total of 302 MUs with recruitment thresholds ranging from 1% to 88% of maximal voluntary contraction
were recorded in the human tibialis anterior muscle in five subjects. The mean (±SD) MU force was 98.3±93.3 mN (mean torque
16.8±15.9 mNm) and the mean contraction time (CT) 46.2±12.7 ms. The correlation coefficients (r) between MU twitch force and CT versus the recruitment threshold in voluntary contractions were +0.68 and –0.38 (P<0.001), respectively. In voluntary contractions, MUs were recruited in order of increasing size except for only 6% of the
cases; whereas, during transcutaneous electrical stimulation (ES) at the muscle motor point, MU pairs showed a reversal of
recruitment order in 28% and 35% of the observations, respectively, when the pulse durations were 1.0 ms or 0.1 ms. This recruitment
reversal during ES was not related to the magnitude of the difference in voluntary recruitment thresholds between MUs. It
is concluded that if the reversal of MU recruitment observed during ES is biophysically controlled by differences in their
nerve axon input impedance, in percutaneous stimulation at the motor point, other factors such as the size and the morphological
organisation of the axonal branches can also influence the order of activation.
Received: 24 May 1996 / Accepted: 30 September 1996 相似文献
112.
Linda R. Gannon Stephen N. Haynes Jackie Cuevas Ralph Chavez 《Journal of behavioral medicine》1987,10(4):411-423
The psychophysiological correlates of induced headaches were examined. Subjects with frequent muscle-contraction headaches, frequent migraine headaches, or infrequent headaches were exposed to a 1-h cognitive stressor while multiple electromyographic and cardiovascular measures were monitored. The stressor was associated with significant changes in all psychophysiological measures. Eleven of 16 headache subjects and 2 of 8 control subjects developed headaches. Significant associations between several psychophysiological variables and headache occurrence were found and individual differences in the association between psychophysiological variables and headaches intensity were examined. The results were consistent with the hypothesized role of cardiovascular factors in the pathophysiology of muscle-contraction headache. This was the first controlled demonstration of headaches occurring as a function of environmental stressors.This research was supported by Grant 5-R01-NS-1875 from the National Institute of Health. 相似文献
113.
目的:通过对食管和贲门癌原发病灶和淋巴结转移病灶肿瘤抑制基因p53变化规律的研究,加深对食管和贲门癌转移发生的分子学基础的了解。方法:采用组织病理学和免疫组织化学(ABC)方法,对31例手术切除的食管和贲门癌原发病灶和转移病灶肿瘤抑制基因p53蛋白聚集进行比较研究。结果:31例手术标本中,病理检查发现24例食管鳞状细胞癌,7例为贲门腺癌。研究表明:24例食管原发和转移鳞癌中,11例原发和转移病灶中均出现p53蛋白聚集的变化,原发和转移病灶的一致性变化发生率为61%(11/18);在6例原发病灶p53免疫组化阴性患者中,其淋巴结转移病灶也同时出现免疫阴性反应。在7例胃贲门腺癌中,3例原发和转移病灶同时出现p53免疫阳性表达的一致率为50%(3/6);1例原发病灶p53免疫组化阴性患者,其淋巴结转移病灶也出现阴性反应。结论:肿瘤抑制基因p53在食管和贲门癌癌变和转移中起一定的作用。可能是食管和贲门癌侵袭与转移过程中值得重视的生物学指标之一。 相似文献
114.
A male infant is described in whom congenital anomalies were recognized prenatally by ultrasound examination. The infant was delivered following spontaneous labor and died approximately 15 min after birth. An autopsy revealed major anomalies in the central nervous system (holoprosencephaly with premaxillary agenesis), the gastrointestinal system (esophageal atresia) and the heart (tetralogy of Fallot). Chromosomal studies revealed recombinant chromosome 5 [46,XY, rec(5), dup q, inv(5)(p15q32)], resulting in partial trisomy 5q and partial monosomy 5p. Cytogenetic investigation of the family revealed a pericentric inversion of chromosome 5 in the father and paternal grandmother, 46,XY (and XX, respectively,) inv(5)(p15q32). The congenital anomalies in this infant are more extensive and severe than previously reported in cases of recombination aneusomy involving chromosome 5. 相似文献
115.
Kobori Kiyohisa Suzuki Keiji Yoshida Yoji Ooneda Genju 《Virchows Archiv : an international journal of pathology》1979,385(1):29-39
Summary Experimental contraction was produced in the rat mesenteric arteries and the arterial segments were studied morphologically. When the rat mesenteric artery was exposed in physiological saline solution at 37° C and 2–3 mg of methoxamine hydrochloride (10 mg/ml) was dripped onto it, intense contraction was observed for about 30 min but elevation in blood pressure was slight. During the contraction, numerous vacuoles were seen in the medial smooth muscle cells of the arterial segments, and these vacuoles were shown electron microscopically to have double unit membranes, indicating that they were formed by herniation of a part of the adjacent smooth muscle cell body. In the arteries 1–6 h after the end of the contraction, cellular, nuclear and vacuolar membranes and myofilaments of the medial muscle cells were partially lost. 12–24 h after the contraction the arteries exhibited necrosis and desquamation of endothelial cells and platelet adhesion. In the media, smooth muscle cells were completely deprived of cell membranes, myofilaments, nuclei, intracytoplasmic organelles other than mitochondria, and vacuolar membranes. The cytoplasm was filled with fine granular and granulo-vesicular material, and fibrin insudation was observed in these severely damaged cells. Arterial contraction may be an important factor in the induction of arterial lesions. 相似文献
116.
Norio Fukuda Hideaki Fujita Takashi Fujita Shin’ichi Ishiwata 《Pflügers Archiv : European journal of physiology》1996,433(1-2):1-8
Skinned fibres from bovine ventricles exhibited spontaneous tension oscillations when MgADP and inorganic phosphate (Pi)
were added to the solution bathing fibres in the relaxed state (ADP-SPOC). A similar type of oscillation was observed at intermediate
concentrations of free Ca2+ in the absence of MgADP and Pi (Ca-SPOC). To investigate the correlation between ADP-SPOC and Ca-SPOC, we constructed two-dimensional
state diagrams of cardiac muscle using different concentrations of Pi (0–20 mM) and free Ca2+ [pCa=around 5 (+Ca2+), pCa=5.15–6.9 and +EGTA (–Ca2+)], with varying concentrations of MgADP (0–10 mM), with 2 mM MgATP and 2 mM free Mg2+ maintaining ionic strength at 0.15±0.01 M, pH 7.0, 25 °C. The three-dimensional (pCa-Pi-MgADP) state diagram thus obtained
was divided into three regions, i.e. the contraction region in which tension oscillation was undetectable, the spontaneous
tension oscillation (SPOC) region and the relaxation region. We found that the regions of ADP-SPOC and Ca-SPOC were continuously
connected by a single oscillation region sandwiched between the contraction and relaxation regions. The state diagram, which
encompasses physiological conditions, shows that the probability of SPOC is higher in cardiac muscle than in skeletal muscle.
From these results, we suggest that, despite distinct ionic conditions, the molecular state of cross-bridges during SPOC is
common to both ADP-SPOC and Ca-SPOC.
Received 19 February 1996 / Received after revision: 16 July 1996 / Accepted: 14 August 1996 相似文献
117.
利用表面肌电信号评价肌肉疲劳的方法 总被引:7,自引:0,他引:7
表面肌电信号分析是评价局部肌肉疲劳有效的工具。过去由于受信号处理技术的限制,对肌肉疲劳的评价仅局限于等长、恒力收缩。由于适合于非平稳信号分析的频谱估计技术的发展,使得动态收缩条件下的肌肉疲劳评价得以实现,在工效学、康复医学和运动医学等方面开启了新的应用领域。本文论述了利用表面肌电信号评价肌肉疲劳,特别是在肌肉动态收缩期间评价肌肉疲劳的方法,为进一步探讨肌肉疲劳的发生机制提供理论依据。 相似文献
118.
目的 在肌肉等效体模及Beagle犬颈段食管中测定ZRL—Ⅱ型食管腔内加热辐射器的温度分布,探讨其热场分布能否满足食管癌加热治疗的临床需要。方法 ①在肌肉等效体模中测定ZRL—Ⅱ型食管腔内射频加热辐射器的温度分布,②Beagle犬用氯胺酮麻醉、固定。将腔内加热辐射器插入食管腔内,加热45min后分层解剖犬的颈部,同时测量食管外壁、气管、食管周围软组织中的温度。结果 ①在肌肉等效体模中距离导管囊表面1cm的环形体内的温度在43.2℃~43.6℃之间;在距离导管囊表面2cm的环形体内的温度在42.6℃~43.3℃之间,在距离导管囊表面3cm的环形体内的温度在42.6℃~42.8℃之间。②测得Beagle犬颈段食管腔内和外壁的温度为43.5℃,气管内为38.0℃,主动脉旁38.0℃,距食管外壁1cm处的软组织温度为40-3℃,距食管外壁2cm处的软组织温度为39.0℃,而颈部皮下的温度是37.5℃。结论 ①ZRL-Ⅱ型射频食管腔内加热辐射器的热场分布满足临床食管腔内加热的需要,②体模测定与活体动物测定,热场分布存在一定差异,需进一步研究。 相似文献
119.
Ulrich Tibes Edeltraud Haberkorn-Butendeich Frithjof Hammersen 《Pflügers Archiv : European journal of physiology》1977,368(3):195-202
Summary The effect of muscle contraction on lymphatic and plasma [K+], [Na+], [Ca2+], [Mg2+], [Cl–], [Pi], [lactate] ([Lac–]); [creatine] ([Cr]), ideal osmolality (OSM), and [protein] was evaluated in femoral venous blood and lymph specimens sampled from the calf muscles of rabbits before, in the course of, and after contractions. In addition, total [K+], [Na+], [Ca2+], [Mg2+], [Cl–], and [H2O] were analyzed in the muscle tissue. To facilitate lymph sampling both hind limbs were passively flexed and extended, in imitation of natural running movements, by an electrically driven crank. The muscles of one side also performed superimposed rhythmic isotonic contractions. Before contractions, lymphatic [K+], [Na+], [Ca2+], [Mg2+], [Lac–], [Cr], and OSM did not significantly differ from corresponding femoral venous concentrations, [Cl–], and [Pi] were significantly higher, [protein] significantly lower in the lymph than in the plasma. During contractions lymphatic [K+], OSM, [Lac–], and [Pi] were raised significantly more in the lymph compared with the plasma concentrations. [Na+], [Cl–], [Ca2+], and [Mg2+] showed only small changes in the course of contractions and thereafter, and they were altered in a similar way in the lymph and plasma. It was suggested that lymphatic and interstitial concentrations were in equilibrium. Comparing inactive with active muscles, the latter lost K+ but gained Na+, Cl–, and H2O, whereas minimal changes occurred in the [Ca2+] and [Mg2+]. The changes were discussed in connection with the hypothesis that electrolyte shifts might be involved in the activation of the muscular non-proprioceptive interstitial nerve endings which appear to play a role in reflexogenic cardiovascular and respiratory control.A preliminary report of this work has been given elsewhere [33]Supported by Deutsche Forschungsgemeinschaft 相似文献
120.