Physiological effects of dynamic work on a bicycle ergometer combined with different types of static contraction

Summary The effects on heart rate, oxygen uptake, and pulmonary ventilation of muscular exercises, including both dynamic contractions, either simple or combined, were studied in 4 male subjects, aged 21 to 23 years. The dynamic work consisted in cycling on an ergometric bicycle at three power levels: 40, 80, and 100 W. The static work consisted in pushing against, pulling and holding with the arms a 6, 9, 12, or 18 kg load. The physiological effects are expressed as cardiac cost (HR), oxygen cost (VO₂) and ventilation cost (V). The physiological cost of the combined work increases according to the cycling power and to the isometric load developed. A statistical analysis shows that the costs of combined work are not different from the sum of the costs of the static and dynamic contractions measured separately. Thus, the physiological responses to the combinations investigated are of an additive type.     

NMDAR1单克隆抗体抑制谷氨酸诱导的大鼠海马神经元Ca2+内流

目的观察人N-甲基-D-门冬氨酸受体(NMDAR,NR)主亚基(NR1)单克隆抗体mAbN1对谷氨酸诱导的大鼠海马神经元Ca2 内流的影响。方法建立谷氨酸介导的大鼠海马神经元兴奋毒性损伤模型,以mAbN1及MK-801分别预处理海马神经元,用Fluo-3/AM法,在激光扫描共聚焦显微镜下观察对细胞内游离Ca2 浓度([Ca2 ]i)的影响。结果mAbN1能显著抑制谷氨酸所致海马神经元[Ca2 ]i升高,此作用强于MK-801,且其本身对生理状态下神经元[Ca2 ]i无影响。结论mAbN1的抗兴奋毒性作用可能是通过改变NR的蛋白质二级结构从而影响兴奋毒性作用中的Ca2 内流实现的。     

5-羟色胺免疫阳性纤维和终末在大鼠舌下神经伸、缩舌肌运动神经元的分布

5-羟色胺（5－HT）参与舌和面口部精细运动的调节。5－HT对舌下神经运动神经元功能的调控表现为兴奋性作用。本文首先采用免疫组化方法，在光镜下观察了大鼠舌下神经核内5－HT免疫阳性纤维的形态和分布特征。又进一步采用荧光逆行追踪结合固定脑片细胞内LuciferYellow染色和荧光免疫组织化学染色，通过共聚焦激光扫描显微镜观察了伸舌肌（颏舌肌、颏舌骨肌）和缩舌肌（茎突舌肌）运动神经元与5－HT免疫阳性纤维及其终末的解剖学关系。结果证明：舌下神经核有较丰富的5－HT阳性纤维，以尾侧段的背侧部和吻侧段的腹侧部较为密集；根据纤维及其膨体的形态特征，本文将此阳性纤维分为三种类型。5－HT免疫阳性膨体样纤维及其终末与舌下运动神经元的胞体、树突分枝和轴丘及轴突起始段形成紧密接触；这些接触多呈不均匀的簇状（由2～7个紧密接触点组成）分布。定量分析发现：在额舌肌神经元和茎突舌肌神经元，除少量分布在胞体（密度为3．4～6．7／1000μm2）外，主要分布在近段和中段树突分权处附近；但是在颏舌骨肌神经元则集中分布在跑体（密度为10．8～17．6／1000μm2）和近侧树突上。以上所见提示：5－HT对舌下神经核整体行为的调节在不同功能的亚核可能有所选择；5－HT调制舌下运动神经元兴奋性的方式可     

Characterization of a subtype of primary osteoclastoma: Extracellular calcium but not calcitonin inhibits aggressive HLA-DR-positive osteoclastoma possessing ‘functional’ calcitonin receptors

We report here a case of primary osteoclastoma that despite possessing HLA-DR-positive status and ‘functional’ calcitonin receptors, exhibited aggressive in vitro and in vivo bone resorptive activity. In the osteoclast bone slice assay employing scanning electron microscopy, the giant cell-mediated bone resorption was uninhibited by salmon calcitonin (10 nM) and significantly inhibited by raised extracellular calcium (20 mM). In Fura-2AM based microspectrofluorimetric assays, the presence of the ‘functional’ calcitonin receptors was ascertained by a rise in intracellular calcium induced by calcitonin and high extracellular calcium. These findings provide evidence for a hitherto unrecognized subtype of giant cells that have HLA-DR-positive status, exhibit avid bone resorptive activity, but remain insensitive to calcitonin despite possessing calcitonin receptors.     

大鼠脑组织细胞培养的形态学观察

为观察原代培养 SD大鼠大脑组织 ,包括神经干细胞在内的各种细胞的形态 ,取新生大鼠 ,无菌操作下取出整个大脑 ,制备成单细胞悬液 ,接种培养 ,免疫细胞化学鉴定各类细胞的同时用光镜和扫描电镜对不同阶段和种类的细胞进行形态学观察。结果显示 :在体外培养出神经元、胶质细胞和神经干细胞 ;神经细胞在体外的发育时程跟体内基本一致 ,神经干细胞在体外 2 0 d左右分化成熟 ,获取了神经细胞和干细胞体外培养的光镜和扫描电镜形态。结果提示 ,成体神经细胞体外分离、培养的条件关键点在于尽可能贴近自然 ,由此可保证细胞培养的质量 ,获得可靠的神经干细胞、神经元和胶质细胞。为各类神经细胞提供了形态学资料。     

The fourth-generation centrifugal blood pump

 The NEDO Gyro permanently implantable (PI) centrifugal blood pump has been developed as a simple, durable, centrifugal blood pump without a complex magnetic suspension system. In vitro studies were performed using a Gyro PI pump with the transparent pump housing in a mock circuit. These studies revealed that the impeller transfers to a floating or a top contact condition, which was dependent on the revolutions per minute (RPM). This pump can be easily converted from a left ventricular assist device (LVAD) to a right ventricular assist device (RVAD) by simply adding a spacer between the pump and the actuator. In order to optimize the impeller suspension for the LVAD and RVAD, spacers of the proper thickness are inserted between both of the pumps and the actuators to regulate the magnetic force. Two Gyro PI pumps were implanted in a bovine model in a 3-month biventricular assist device (BVAD) animal study. This experiment was electively terminated 90 days after implantation. All of the parameters, including pump flow rate, power consumption, and plasma free hemoglobin, were in acceptable ranges. No thrombus formation was observed in either pump. Antithrombogenesis and effectiveness were demonstrated in this animal study. The NEDO Gyro PI pump is ready to move on to the 3-month preclinical system evaluation. Received: February 28, 2002 / Accepted: May 30, 2002 Acknowledgment The New Energy and Industrial Technology Development Organization (NEDO) under the Ministry of Economy, Trade and Industry of Japan financially supported this project. Correspondence to:S. Ichikawa     

Local thermal sensation and finger vasoconstriction in the locally heated hand

Summary The effects of local heating on finger blood flow (BF) and local thermal sensation (Sens _w ) were studied. Finger BFs in both hands were measured simultaneously; one hand was immersed in water the temperature (T _w ) of which was raised from 35° C to 43°C by steps of 2° C every 10 min, while the other hand was kept atT _w 35°C. FingerBF in the locally heated hand decreased atT _w 37 to 41°C, while fingerBF in the control hand did not alter. Sens_w, in the heated hand showed a dynamic response, initially increasing concomitantly with an increase inT _w , then gradually returning and adapting to a new level of Sens_w. The dynamic response of Sens_w, was not perceived during mental calculation even whenT _w was raised to 40°C, and the reduction in finger blood flow was not observed. These results suggest that finger vasoconstriction caused by local heating closely relates to the dynamic response characteristic of local thermal sensation atT _w above core temperature, and that the perception of local thermal sensation in the central nervous system is involved in the mechanism of this vasoconstrictor response.     

线扫描直接数字化X线摄影原理与应用

目的 探讨线扫描直接数字化X线摄影的工作原理与实用价值。方法 以多丝正比室线扫描X线摄影系统为基础，分析线扫描直接数字化X线摄影的适用性。结果 线扫描成像技术克服了散射线造成的干扰，且探测灵敏度和精密度分辨率高。结论 线扫描成像技术适合于除了动态摄影以外的各种数字X线摄影，对我国常规X线摄影逐步实现数字化开辟了美好的前景。     

磁场对微循环的影响

为了探讨磁场对微循环的作用，利用直径０．７ｃｍ、表面磁感强度０．３Ｔ的磁片及磁感强度０．１Ｔ、转速２５００ｒ／ｍｉｎ的旋磁机分别作用于受试者左手无名指３０ｍｉｎ，并记录作用前后微循环改变。结果表明，动、静磁场均可使微血管清晰度、血流速及管径有明显改变，而对管袢数与红细胞聚集没有影响。这一结果提示，微血管扩张、血流速加快是磁场改善微循环的基础。     

Significance of skin temperature changes in surface electromyography

Summary Differing results have been reported concerning the direction and quantity of the electromyogram (EMG) amplitude response to changes in tissue temperature. The EMG signals from the soleus muscle of six healthy human subjects were therefore recorded during dynamic exercise (concentric contractions) at ambient temperatures of 30°C and 14°C. The mean skin temperature above the muscle investigated was 32.9° C and 21.7° C, respectively. The core temperature, estimated by rectal temperature, was unchanged. The cooling of the superficial tissues caused approximately a doubling of the EMG amplitude. For the probability level 0.9 in the amplitude probability distribution function, the average signal level increased from 73 V to 135 V (P=0.02). The average mean power frequency of the EMG signal was reduced from 142 Hz to 83 Hz (P=0.004). The amplitude increase was not due to shivering but other possible explanations are presented. As the changes in T _sk investigated were within the range which may occur normally during the working hours, it was concluded that T _sk should be carefully controlled in vocational EMG studies.