初乳和成熟乳钙的测定及临床意义

本文对４７０例产妇初乳钙含量的检测发现，２５２例产妇初乳钙＜３０ｍｇ／ｄｌ，低钙发生率为５３．６％。其中妊高征组低钙发生率为７６．４％，明显高于正常妊娠组；剖宫产与正常产乳钙值无明显差异。检测产后１个月成熟乳钙１５０例，其中３７例乳钙含量＜３０ｍｇ／ｄｌ，低钙发生率为２４．６％。明显低于初乳（Ｐ＜０．０１）。本文通过母乳钙测定为正确指导母亲及婴儿合理补钙提供了理论依据，对预防孕妇并发症及婴儿佝偻病的发生有重要意义     

神经肽Y活化大鼠心肌细胞内Ca^2＋及钙调素依赖的钙调神经磷酸酶途径

目的 观察神经肽 Y （NPY）对心肌细胞内Ca^2＋及钙调素（CaM）依赖的钙调神经磷酸酶（CaN）信号传导途径的影响.方法 以NPY刺激心肌细胞.用环胞素A（CsA）特异性抑制CaN活性.应用Western印迹测细胞内CaN-α蛋白表达.采用组织化学法测CaN酶活性.用Fluo3-AM荧光标记法观察心肌细胞胞质及核内钙离子浓度变化.结果 加入100 nmol/L NPY刺激后,心肌细胞CaN酶活力较对照组明显增高（P＜0.05）,10 nmol/L NPY组和CsA 组（100 nmol/L NPY ＋ 5 μg/ml CsA） CaN酶活性与对照组相比,差异无统计学意义.100 nmol/L NPY组心肌细胞内CaN-α蛋白表达较对照组显著增高（P＜0.05）. 加入100 nmol/L NPY在10 min内,心肌细胞胞浆及核内钙含量与对照组相比,差异无统计学意义.经100 nmol/L NPY刺激24 h后,心肌细胞胞浆及核内钙含量明显高于对照组（P均＜0.01）.结论 NPY可活化心肌细胞内Ca^2＋及CaM-CaN途径.NPY刺激下产生的细胞内钙增加,可能是其活化CaN途径的始动环节.     

神经肽Y活化大鼠心肌细胞内Ca2+及钙调素依赖的钙调神经磷酸酶途径

目的 观察神经肽 Y (NPY)对心肌细胞内Ca2+及钙调素(CaM)依赖的钙调神经磷酸酶(CaN)信号传导途径的影响.方法 以NPY刺激心肌细胞.用环胞素A(CsA)特异性抑制CaN活性.应用Western印迹测细胞内CaN-α蛋白表达.采用组织化学法测CaN酶活性.用Fluo3-AM荧光标记法观察心肌细胞胞质及核内钙离子浓度变化.结果 加入100 nmol/L NPY刺激后,心肌细胞CaN酶活力较对照组明显增高(P＜0.05),10 nmol/L NPY组和CsA 组(100 nmol/L NPY + 5 μg/ml CsA) CaN酶活性与对照组相比,差异无统计学意义.100 nmol/L NPY组心肌细胞内CaN-α蛋白表达较对照组显著增高(P＜0.05). 加入100 nmol/L NPY在10 min内,心肌细胞胞浆及核内钙含量与对照组相比,差异无统计学意义.经100 nmol/L NPY刺激24 h后,心肌细胞胞浆及核内钙含量明显高于对照组(P均＜0.01).结论 NPY可活化心肌细胞内Ca2+及CaM-CaN途径.NPY刺激下产生的细胞内钙增加,可能是其活化CaN途径的始动环节.     

丹参对抗缺氧/复氧引起的大鼠心室肌细胞收缩和细胞内钙的改变

目的:观察丹参在常氧和缺氧/复氧过程中对心肌细胞收缩和电刺激诱导的细胞内钙([Ca²⁺]_i)瞬态的影响。方法: 采用酶解分离成年大鼠心室肌细胞化学缺氧模型, 用视频跟踪计算机系统和细胞内双波长钙荧光系统分别观察心肌细胞收缩力学和[Ca²⁺]_i等指标。结果:丹参(1-9 g/L)处理后降低心肌细胞最大收缩和舒张速率、收缩幅度以及电刺激诱导的[Ca²⁺]_i幅度, 且呈剂量依赖性。缺氧后, 与对照相比细胞收缩力和钙瞬态幅度降低、舒张末细胞长度缩短、舒张末钙水平增高;复氧后细胞收缩力、钙瞬态幅度和舒张末钙水平有所回复, 但不能达对照水平。用3 g/L的丹参处理后, 缺氧/复氧引起的心肌细胞最大收缩和舒张速率、收缩幅度和电刺激诱导的[Ca^2＋]_i幅度高于单纯缺氧组, 舒张末[Ca²⁺]_i水平低于单纯缺氧组。结论:丹参可对抗缺氧/复氧引起的大鼠心室肌细胞收缩力降低和细胞内动态和静态钙的变化。     

蒺藜皂苷对缺氧/复氧诱导大鼠皮层神经元凋亡及细胞内钙变化的作用

目的： 观察蒺藜皂苷(TTLS)对缺氧/复氧诱导的大鼠皮层神经元凋亡及细胞内游离钙离子浓度变化的影响。方法： 原代培养大鼠皮层神经元，建立缺氧/复氧损伤的皮层神经元凋亡模型。比色法测定细胞乳酸脱氢酶（LDH）释放漏出率；Annexin V-FITC/PI双染，流式细胞仪定量分析细胞凋亡百分率；Fluo-3荧光染色，激光扫描共聚焦显微镜观察细胞内钙平均荧光值变化。结果： 缺氧3 h复氧12 h可诱导出皮层神经元凋亡，引起细胞内钙离子浓度增高,高于对照组（P<0.01）。蒺藜皂苷(0.025 g/L)能明显降低缺氧/复氧诱导的神经元凋亡，并可降低细胞内钙浓度,与模型组比较有显著差异（P<0.01）。结论： 蒺藜皂苷可降低由缺氧/复氧诱导的皮层神经元的凋亡，减轻细胞损伤，这种作用机制可能与其抑制神经细胞内钙超载有关。     

实时三维超声成像的原理及其临床应用前景

近年来 ,三维超声成像技术飞速发展 ,在临床诊断上已取得良好的成效。实时三维的出现 ,使之又获长足的进步。今就其成像原理、应用现状及其发展前景简介如下。1　实时三维超声成像原理动态三维超声心动图 (ｄｙｎａｍｉｃｔｈｒｅｅ -ｄｉｍｅｎｓｉｏｎａｌｅｃｈｏｃａｒｄｉｏｇｒａｐｈｙ)在采集信息时需要以平行、扇形或旋转方式改变转动换能器方向。在心脏检查过程中如用旋转法需在每一方位采集一个完整心动周期的二维图像 ,全方位转动 180°时需要积累 6 0～ 90个心动周期的二维图像 ,再将这 10 0 0余帧二维图像数字化存储为锥体形数…     

血氧水平依赖功能磁共振成像的基本原理及方法学应用

功能磁共振成像(functional magnetic resonance imaging,fMRI)是研究脑功能的一种强有力的方法,具有无创定位、高空间分辨率和时间分辨率的特点。最基本的fMRI的成像技术是血氧水平依赖功能磁共振成像(blood oxygen level dependent fMRI,BOLD-fMRI)。概述了BOLD-fMRI的基本原理以及在方法学上的应用。     

成熟和衰老T细胞活化后钙信号的研究进展

成熟和衰老的T细胞活化后，多种因素参与形成钙信号，该信号对T细胞活化的效应发挥重要的调控作用。衰老的T细胞钙信号的形成和调控均出现显著变化，细胞活化后不能产生充分的钙信号，钙信号减弱可能是衰老T细胞功能低下的重要原因之一。本文对T细胞活化后，钙信号的形成机制、细胞膜上及膜内钙离子通道和线粒体在钙信号形成中的调控作用、衰老T细胞钙信号的变化特点及影响因素综述如下。     

The possible pitfalls of the measurement of intracellular calcium concentration of lymphocytes with the fluorescent indicator quin2

The measurement of intracellular calcium concentration of small cells became feasible and relatively easily accomplishable following the development of the fluorescent calcium chelating dye, quin2, by R. Y. Tsien and his co-workers. The present paper gives an experimental survey of the major possible pitfalls of the method such as: 1) the improper choosing of the concentration of quin2/AM, 2) the misinterpretation of the calibration procedure, 3) the accidental heavy metal traces in the medium, and 4) the uneven distribution of quin2 among the individual cells or within a certain cell. We report some original data on: 1) the distorting effect of heavy metal ions on the measurement and the use of chelex 100 resin to eliminate heavy metal traces from the mediums, 2) the negligible contribution of dead cells to the overall fluorescence signal demonstrated by flow-cytometry, and 3) fluorescence polarization of quin2 in lymphocytes.     

Effects of calcium chelators on intracellular calcium and excitotoxicity

In an attempt to probe the relationship between excitotoxicity and increases in intracellular calcium ([Ca²⁺]_i), BAPTA-AM and its analogs were applied to cultured hippocampal neurons. Chelation of [Ca²⁺]_i depressed and prolonged transient responses to glutamate and did not effect elevation of [Ca²⁺]_i by prolonged exposure. This explains the inability of the chelators to prevent glutamate-induced toxicity.     

In situ imaging of intracellular calcium with ischemia in lung subpleural microvascular endothelial cells

We propose that generation of reactive oxygen species (ROS) during ischemia is associated with an increase in intracellular calcium ([Ca2+]i) in pulmonary capillary endothelial cells. We used an isolated rat lung model and epifluorescence microscopy to evaluate [Ca2+]i in subpleural microvascular endothelial cells in situ by ratio imaging of the fluorophores, Calcium Green and Fura Red (CG/FR). Lungs were ventilated continuously under control (continuously perfused) or global ischemia (no perfusion) and thus remained adequately oxygenated even with ischemia. Ischemia for 5 min led to increase in CG/FR, indicating increase in [Ca2+]i in endothelial cells in situ; CG/FR remained elevated during a subsequent 10 min of ischemia. Ca(2+)-free perfusion and gadolinium (100 microM) inhibited the increase in [Ca2+]i, while thapsigargin (250 nM) had no effect. These results indicate that increase in endothelial cell [Ca2+]i with ischemia was due to influx from the extracellular medium. Perfusion with N-acetyl-L-cysteine (20 mM) or diphenyleneiodonium chloride (10 microM) prevented the ischemia-mediated [Ca2+]i increase, suggesting a role for ROS in the Ca2+ changes with ischemia. Membrane depolarization by perfusion with high potassium (K+) or glyburide also resulted in increased [Ca2+]i whereas the K(+)-channel agonist cromakalim, inhibited ischemia-mediated Ca2+ influx. We conclude that increased ROS generation with 'oxygenated' lung ischemia is associated with influx of Ca2+ and an increase in endothelial cell cytosolic calcium concentration.     

联合成像系统研究心肌细胞微区力学及细胞内钙离子变化

目的 使用联合成像系统在亚细胞水平研究心肌细胞微区力学性质及细胞内钙离子的快速变化,并探讨两者之间的关系.方法 应用原子力显微镜(AFM)和激光扫描共聚焦显微镜(LSCM)组合成的联合成像系统对急性分离的大鼠单个心室肌细胞微区力进行检测,同时测定细胞内钙离子浓度的变化,分析细胞微区力和细胞内钙离子浓度变化两者之间的相关性.结果 观察到心肌细胞内钙离子浓度的快速变化引起了钙波的传递.通过AFM微悬臂的偏转可以计算出细胞微区力,细胞微区力的大小与细胞内钙离子浓度呈正相关(r=0.701,P=0.003).结论 联合成像系统可以同步研究心肌细胞微区力学及细胞内分子快速变化,进而在亚细胞水平研究心脏疾病的发病机制.     

Measurement of intracellular calcium.

To a certain extent, all cellular, physiological, and pathological phenomena that occur in cells are accompanied by ionic changes. The development of techniques allowing the measurement of such ion activities has contributed substantially to our understanding of normal and abnormal cellular function. Digital video microscopy, confocal laser scanning microscopy, and more recently multiphoton microscopy have allowed the precise spatial analysis of intracellular ion activity at the subcellular level in addition to measurement of its concentration. It is well known that Ca2+ regulates numerous physiological cellular phenomena as a second messenger as well as triggering pathological events such as cell injury and death. A number of methods have been developed to measure intracellular Ca2+. In this review, we summarize the advantages and pitfalls of a variety of Ca2+ indicators used in both optical and nonoptical techniques employed for measuring intracellular Ca2+ concentration.     

The dynamic range and domain-specific signals of intracellular calcium in photoreceptors

Vertebrate photoreceptors consist of strictly delimited subcellular domains: the outer segment, ellipsoid, cell body and synaptic terminal, each hosting crucial cellular functions, including phototransduction, oxidative metabolism, gene expression and transmitter release. We used optical imaging to explore the spatiotemporal dynamics of Ca(2+) signaling in non-outer segment regions of rods and cones. Sustained depolarization, designed to emulate photoreceptor activation in the darkness, evoked a standing Ca(2+) gradient in tiger salamander photoreceptors with spatially-averaged intracellular Ca(2+) concentration within synaptic terminals of approximately 2 microM and lower (approximately 750 nM) intracellular calcium concentration in the ellipsoid. Measurements from axotomized cell bodies and isolated ellipsoids showed that Ca(2+) enters the two compartments via both local L-type Ca(2+) channels and diffusion. The results from optical imaging studies were supported by immunostaining analysis. L-type voltage-operated Ca(2+) channels and plasma membrane Ca(2+) ATPases were highly expressed in synaptic terminals with progressively lower expression levels in the cell body and ellipsoid. These results show photoreceptor Ca(2+) homeostasis is controlled in a region-specific manner by direct Ca(2+) entry and diffusion as well as Ca(2+) extrusion. Moreover, quantitative measurement of intracellular calcium concentration levels in different photoreceptor compartments indicates that the dynamic range of Ca(2+) signaling in photoreceptors is approximately 40-fold, from approximately 50 nM in the light to approximately 2 microM in darkness.     

The influence of extracellular and intracellular calcium on the secretion of renin

Changes in plasma, extracellular, and intracellular calcium can affect renin secretion from the renal juxtaglomerular (JG) cells. Elevated intracellular calcium directly inhibits renin release from JG cells by decreasing the dominant second messenger intracellular cyclic adenosine monophosphate (cAMP) via actions on calcium-inhibitable adenylyl cyclases and calcium-activated phosphodiesterases. Increased extracellular calcium also directly inhibits renin release by stimulating the calcium-sensing receptor (CaSR) on JG cells, resulting in parallel changes in the intracellular environment and decreasing intracellular cAMP. In vivo, acutely elevated plasma calcium inhibits plasma renin activity (PRA) via parathyroid hormone-mediated elevations in renal cortical interstitial calcium that stimulate the JG cell CaSR. However, chronically elevated plasma calcium or CaSR activation may actually stimulate PRA. This elevation in PRA may be a compensatory mechanism resulting from calcium-mediated polyuria. Thus, changing the extracellular calcium in vitro or in vivo results in inversely related acute changes in cAMP, and therefore renin release, but chronic changes in calcium may result in more complex interactions dependent upon the duration of changes and the integration of the body’s response to these changes.     

Stability and instability of regulation of intracellular calcium

[Ca2+]i is used as a signal in many tissues. In this review we discuss the mechanisms that regulate [Ca2+]i and, importantly, what determines their stability. Brief mention is made of the effects of feedback gain and delays on stability. The control of cytoplasmic Ca concentration is shown to be generally stable as Ca pumping is essentially an instantaneous function of [Ca2+]i. In contrast, regulation of the Ca content of intracellular stores may be less stable. One example of this is instability in the control of sarcoplasmic reticulum (SR) Ca content in cardiac muscle. An increase of SR Ca content increases the systolic Ca transient amplitude. This in turn decreases Ca influx into the cell and increases efflux, thereby restoring SR Ca to control levels. This feedback system has an inherent delay and is potentially unstable if the gain is increased beyond a certain level. This instability produces Ca transients of alternating amplitude and may contribute to the clinical syndrome of pulsus alternans.     

Flow cytometric measurement of intracellular cytokines

The identification of distinct T helper lymphocyte subsets (Th1/2) with polarised cytokine production has opened up new fields in immunobiology. Of the several alternative methods of monitoring cytokine production, flow cytometric analysis of intracellular staining has distinct advantages and pitfalls. It allows high throughput of samples and multiparameter characterisation of cytokine production on a single cell basis without the need for prolonged in vitro culture and cloning. However, these methods may cause important changes in cell surface phenotype which can make interpretation difficult.