低强度He- Ne 激光与丹参注射液联用对牛中性粒细胞呼吸爆发的影响

为了探讨低强度Ｈｅ -Ｎｅ激光与丹参注射液联合作用在细胞水平的生物效应 ,本文应用粒细胞的化学发光法[1] 检测了单用低强度Ｈｅ -Ｎｅ激光或丹参注射液、低强度Ｈｅ -Ｎｅ激光与丹参注射液联用对中性粒细胞呼吸爆发的影响 ,以进一步探讨其抗缺血、缺氧性损伤的机制 .1　材料和方法1 .1　材料　　趋化三肽 (Ｎ -ｆｏｒｍｙｌ-ｍｅｔｈｉｏｎｙｌ-ｌｅｕｃｙｌ-ｐｈｅｎｙｌａｌａｎｉｎｅ ,ｆＭＬＰ) ,鲁米诺 ( 5-ａｍｉｎｏ - 2 ,3-ｄｉ ｈｙｄｒｏ - 1 ,4-ｐｈｔｈａｌａｚｉｎｅｄｉｏｎｅ ,Ｌｕｍｉｎｏｌ) ,ＤｅｘｔｒａｎＴ - 50 0…     

Fluorescence detection and imaging of cytosolic calcium oscillations: A comparison of four equipment setups

The increase in cytosolic calcium concentration has been shown to play an important role in vital cellular functions such as muscle contraction, cell secretion, oocyte fertilization, nerve conduction, embryo development and apoptosis in animals, plants and microbes, and in the invasion of mammalian cells by parasites, bacteria, and viruses. Therefore, live cell imaging of increases in cytosolic calcium concentration in cellular compartments has been investigated intensively. Multiple calcium imaging systems are now available commercially, but when it comes to deciding which model to purchase, it is often hard to obtain enough information for an optimal setup. In this paper, a comparison was made among four fluorescent detection/imaging devices for the detection of cytosolic calcium oscillations induced in rat pancreatic acinar cells by cholecystokinin and in hepatocytes by phenylephrine. Detailed equipment setup, differences in data acquisition and analysis, and side effects of the excitation light on live cells were analyzed. A list of important factors that should be considered in choosing the optimal equipment are recommended, which will be useful for users of such devices in the future.     

H2O2信息分子功能的探索—H2O2对人中性粒细胞呼吸爆发的反馈调节

ROS 作为信息分子是生命科学研究中继发现 NO 是信息分子后的又一重要事件。探索了外源性 ROS(H_2O_2)对人中性粒细胞(Np)呼吸爆发产物 O_2水平的影响,结果表明外源性 H_2O_2对 Np呼吸爆发水平有反馈调节作用。     

Early steps of lymphocyte activation bypassed by synergy between calcium ionophores and phorbol ester

Although it has been proposed that the activation of T lymphocytes is mediated by an early rise in cytosolic calcium concentration, it has not been possible to mimic antigen- or mitogen-induced mouse lymphocyte activation by calcium ionophores that bypass receptor-mediated processes. There is now evidence from other systems that the rise in cytosolic calcium which follows receptor triggering is preceded by the breakdown of phosphatidylinositol bisphosphate into 1,2-diacylglycerol and inositol trisphosphate. The latter is known to cause release of calcium from intracellular stores. The cellular target for the former is now widely accepted to be protein kinase C. Therefore, ligand-induced cellular response follows a rise in cytosolic calcium concentration and protein kinase C activation. Here we confirm that the calcium ionophores A23187 and ionomycin do not activate mouse T lymphocytes. However, either one in combination with the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA), which is structurally related to 1,2-diacylglycerol, induces in lymphoid cell populations the expression of receptors for interleukin-2 (IL-2), the secretion of IL-2 and cell proliferation as measured by 3H-thymidine uptake. The growth-promoting effect of IL-2 on an exogenous IL-2-dependent clone could not be substituted for by ionomycin either alone or with TPA. Thus, the combination of calcium ionophores and TPA bypasses the requirement for antigen- or lectin-induced signal at the onset of lymphocyte activation.     

Oscillations of cytosolic Ca2+ in pituitary cells due to action potentials

Electrical activity in non-neuronal cells can be induced by altering the membrane potential and eliciting action potentials. For example, hormones, nutrients and neurotransmitters act on excitable endocrine cells. In an attempt to correlate such electrical activity with regulation of cell activation, we report here direct measurements of cytosolic free Ca2+ changes coincident with action potentials. This was achieved by the powerful and novel combination of two complex techniques, the patch clamp and microfluorimetry using fura 2 methodology. Changes in intracellular calcium concentration were monitored in single cells of the pituitary line GH3B6. We show that a single action potential leads to a marked transient increase in cytosolic free calcium. The size of these short-lived maxima is sufficient to evoke secretory activity. The striking kinetic features of these transients enabled us to identify oscillations in intracellular calcium concentration in unperturbed cells resulting from spontaneous action potentials, and hence provide an explanation for basal secretory activity. Somatostatin, an inhibitor of pituitary function, abolishes the spontaneous spiking of free cytosolic Ca2+ which may explain its inhibitory effect on basal prolactin secretion. Our data therefore demonstrate that electrical activity can stimulate Ca2+-dependent functions in excitable non-neuronal cells.     

钙稳态失衡与细胞凋亡的研究现状

细胞胞浆钙离子浓度必须处于严格的范围，一旦钙稳态失调将导致细胞损伤或死亡．本文主要从外界因素引起钙稳态失调导致细胞死亡的作用、直接钙稳态失调所致的细胞死亡效应及钙离子在细胞凋亡中的作用等方面作一综述。     

镉对油菜花粉细胞内钙离子浓度的影响

应用激光扫描共聚焦显微系统(LSCM)和fluo-3 AM荧光探针标记技术,观察了不同浓度Cd2+对油菜花粉细胞内游离Ca2+的影响。发现油菜花粉经水合培养后,胞内Ca2+呈极性分布,萌发沟附近浓度较高,花粉管萌生部位浓度最高;胞外环境中Cd2+可使细胞内游离Ca2+的浓度升高,表明油菜花粉受重金属Cd2+毒害后,可通过调动胞质内游离Ca2+的变化而做出对外界刺激的应答。这一实验结果为探索重金属对植物的毒害机理提供了新的证据。     

Stimulated neutrophils from patients with autosomal recessive chronic granulomatous disease fail to phosphorylate a Mr-44,000 protein

Phagocytosing neutrophils, monocytes, macrophages and eosinophils produce a burst of non-mitochondrial respiration that is important for the killing and digestion of microbes. Much of the information about the oxidase system involved comes from studies on patients with chronic granulomatous disease (CGD), a syndrome in which an undue predisposition to infection results from complete absence of this burst of stimulated respiratory activity. The basis of the oxidase activity is an electron transport chain, the only established component of which is a very unusual b-type cytochrome (b-245) (ref. 2). The molecular defect in the X-linked subgroup of CGD is the absence of this cytochrome b-245, which, however, appears to be normal in those subjects with the autosomal recessive mode of inheritance. In an attempt to identify an abnormality of activation, or an absence or malfunction of a proximal component of the electron transport chain in this latter group, we examined protein phosphorylation in neutrophils after activation of the oxidase with phorbol myristate acetate. All four of the patients studied demonstrated a selective lack of the enhanced phosphorylation of a protein of relative molecular mass (Mr) 44,000 (44K) that was observed in normal subjects and in two CGD patients with an X-linked inheritance. This molecule, therefore, could be an important functional component of the oxidase.     

电针镇痛对小鼠脑细胞游离Ca2+浓度的影响

实验探讨电针镇痛及钙通道阻断剂盐酸异博定(verapamil)、硝苯吡啶(nifedipine)对小鼠海马细胞及突触体游离Ca^2 浓度的影响．采用荧光染料Fura-2／AM测定在电针镇痛期间，小鼠海马细胞及突触体内游离钙浓度([Ca^2 ]i)的改变．结果表明电针镇痛时，海马细胞内[Ca^2 ]．升高，而突触体[Ca^2 ]i降低，向分离出的突触体培养液内加入钙通道阻断剂盐酸异博定、硝苯吡啶，突触体[Ca^2 ]．明显降低．提示电针的镇痛效应可能与海马神经细胞膜内、外钙离子浓度的变化有关．     

微乳法制备纳米硅酸钙

利用溶剂热的方法,在阳离子表面活性剂CTAB(十六烷基三甲基溴化胺)的存在下,制备出了不同形貌的硅酸钙纳米晶粒.通过改变水与表面活性剂的浓度的比值,发现对产物硅酸钙形貌的控制有着重要的影响,并对硅酸钙的生成机理做了初步的探讨,认为水与表面活性剂的浓度比值在反应物的浓度逐渐增大时,胶团的内部有更多的反应物聚集,使产物尺寸变大,促进了产物的晶化,易形成棒状的结构;反之,易得到球形的纳米晶.     

Protein kinase C regulation of the receptor-coupled calcium signal in histamine-secreting rat basophilic leukaemia cells

It has been proposed that protein kinase C mediates cellular responses evoked by external stimuli, leading to alterations in internal free calcium concentrations. We have shown previously that histamine-secreting rat basophilic leukaemia cells (RBL-2H3), which degranulate on aggregation of the receptors for immunoglobulin IgE, contain a Ca2+- and phospholipid-dependent protein kinase (kinase C). The partially purified enzyme is activated directly by the tumour-promoting phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). In intact RBL cells, TPA potentiates histamine release induced by the Ca2+-ionophore A23187 (similar to the synergy reported for platelets, neutrophils and rat peritoneal mast cells). Although TPA at concentrations below 15 nM synergizes with the antigen, higher TPA concentrations inhibit secretion. This selective inhibition suggested that kinase C is involved in both the activation and termination of the secretory process. To examine this possibility, we have determined the effect of TPA on changes in free cytosolic Ca2+ concentration during antigen-induced release. We report here that TPA completely blocks the increase in Ca2+ concentration induced by antigen. Our results strongly suggest that protein kinase C is involved in the regulation of receptor-dependent Ca2+ signalling.     

A model of calcium signaling and degranulation dynamics induced by laser irradiation in mast cells

Recent experiments show that calcium signaling and degranulation dynamics induced by low power laser irradiation in mast cells must rely on extracellular Ca^2＋ influx. An analytical expression of Ca^2＋ flux through TRPV4 cation channel in response to interaction of laser photon energy and extracellular Ca^2＋ is deduced, and a model characterizing dynamics of calcium signaling and degranulation activated by laser irradiation in mast cells is established. The model indicates that the characteristics of calcium signaling and degranulation dynamics are determined by interaction between laser photon energy and Ca^2＋ influx. Extracellular Ca^2＋ concentration is so high that even small photon energy can activate mast cells, thus avoiding the possible injury caused by laser irradiation with shorter wavelengths. The model predicts that there exists a narrow parameter domain of photon energy and extracellular Ca^2＋ concentration of which results in cytosolic Ca^2＋ limit cycle oscillations, and shows that PKC activity is in direct proportion to the frequency of Ca^2＋ oscillations. With the model it is found that sustained and stable maximum plateau of cytosolic Ca^2＋ concentration can get optimal degranulation rate. Furthermore, the idea of introducing the realistic physical energy into model is applicable to modeling other physical signal transduction systems.     

A role for calpactin in calcium-dependent exocytosis in adrenal chromaffin cells

Stimulation of bovine adrenal chromaffin cells results in a rise in the concentration of cytosolic calcium which triggers the release of catecholamines by exocytosis. Several cytosolic proteins that bind to secretory granule membranes in a calcium-dependent manner have been implicated in exocytosis and some belong to a family of calcium-binding proteins, the annexins. One of these, calpactin, is a tetramer consisting of two heavy and two light chains (relative molecular masses 36,000 and 10,000 respectively) and can aggregate and fuse membranes in vitro in the presence of arachidonic acid. Calpactin is found at the cell periphery and is phosphorylated when chromaffin cells are stimulated. We show here that both calpactin and calpactin heavy chain (p36) reconstitute secretion in permeabilized chromaffin cells in which secretion has been reduced as a result of leakage of cellular components. This effect is inhibited by an affinity-purified antibody against p36. Secretion from permeabilized cells is inhibited by a synthetic annexin-consensus peptide, but not by a nonspecific hydrophobic peptide; this inhibition is reversed by p36. Our results indicate that either calpactin or p36 is essential for exocytosis.     

外源钙对盐胁迫下菊花生理效应影响

 为了探索外源钙能否缓解盐胁迫对栽培菊花的伤害及其适宜浓度,提高盐渍条件下菊花的栽培品质,以不同浓度的外源钙（CaCl2）搭配150mmol/LNaCl溶液分别浇灌盆栽菊花植株,研究盐胁迫条件下外源钙对菊花形态和生理效应的影响。结果表明,在NaCl胁迫条件下,经CaCl2处理植株较无CaCl2处理植株（对照）盛花期延长2d;处理30d后,植株鲜重/干重比值增加7.2%～33.3%;叶内丙二醛（MDA）含量降低6.6%～26.0%;过氧化物酶（POD）活性增加17.4%～67.8%;超氧化物歧化酶（SOD）活性增加1.4%～2.7%;叶绿素（a+b）含量增加10.7%～70.0%。外源CaCl2显著提高了盐胁迫下的菊花抗性,其中以1mmol/L CaCl2效果最佳。     

3种口服钙制剂在兔体内生物利用度的比较

利用原子吸收分光光度法测定兔血清中钙的浓度来比较补钙剂G、葡萄糖酸钙、天门冬氨酸钙3种口服钙制剂在兔体内的生物利用度.结果表明,3种钙制剂间无显著性差异(P>0.05),它们对兔体内钙行为的影响是一致的.     

Potentiation of NMDA receptor currents by arachidonic acid.

Arachidonic acid is released by phospholipase A2 when activation of N-methyl-D-aspartate (NMDA) receptors by neurotransmitter glutamate raises the calcium concentration in neurons, for example during the initiation of long-term potentiation and during brain anoxia. Here we investigate the effect of arachidonic acid on glutamate-gated ion channels by whole-cell clamping isolated cerebellar granule cells. Arachidonic acid potentiates, and makes more transient, the current through NMDA receptor channels, and slightly reduces the current through non-NMDA receptor channels. Potentiation of the NMDA receptor current results from an increase in channel open probability, with no change in open channel current. We observe potentiation even with saturating levels of agonist at the glutamate- and glycine-binding sites on these channels; it does not result from conversion of arachidonic acid to lipoxygenase or cyclooxygenase derivatives, or from activation of protein kinase C. Arachidonic acid may act by binding to a site on the NMDA receptor, or by modifying the receptor's lipid environment. Our results suggest that arachidonic acid released by activation of NMDA (or other) receptors will potentiate NMDA receptor currents, and thus amplify increases in intracellular calcium concentration caused by glutamate. This may explain why inhibition of phospholipase A2 blocks the induction of long-term potentiation.     

L-丝氨酸与L-天门冬氨酸对羟基磷灰石仿生矿化的影响

根据仿生合成原理,以L-丝氨酸(L-Ser)和L-天门冬氨酸(L-Asp)为有机基质,通过气相扩散法制备碳-羟基磷灰石晶体,并在牙釉质片上进行仿生再矿化.通过场发射扫描电子显微镜(FESEM)、X射线衍射(XRD)和Fourier变换红外光谱(FTIR)表征产物结构,并考察不同浓度氨基酸对中间产物碳酸钙和最终产物羟基磷灰石粉体及牙釉质基质的影响.结果表明:氨基酸浓度对溶液中游离晶体粉末的形貌影响较大,由碳酸钙转化为羟基磷灰石,具有形貌遗传性,该影响未体现在牙釉质基质上;吸附在牙釉质基质片的氨基酸作为矿化成核位点,通过调节羟基磷灰石的晶体生长排列方向即可实现原位再矿化.     

Ca^2＋促进丝瓜离体生根

Ca^2 信使系统是植物体内重要的信号通路，它将许多细胞外信号转化为细胞内的信号以影响许多蛋白激酶活性，从而引起植物生长发育的多种反应，在政党Ca^2 浓度下，仅激素处理不能生根的丝瓜外植体，处以不同Ca^2 浓度处理时，随Ca^2 浓度升高，外植体生根数明显加快并增多，且有少量植株叶腑处异化生根，在一定程度上改变了腋芽的发育方向，这说明Ca^2 改变了卷须芽或花芽的发育方向，使其发育为根，但Ca^2 超过一定浓度后会影响外植体的正常营养生长。     

咖啡因对大鼠肾上腺嗜铬细胞钙信号调节作用

在单个大鼠肾上腺嗜铬细胞上，采用钙显微荧光测量方法，测量了咖啡因对胞内游离钙浓度的影响．实验结果表明，在２Ｃａ２＋外液中，咖啡因（１ｍｍｏｌ／Ｌ，１０ｍｍｏｌ／Ｌ，４０ｍｍｏｌ／Ｌ）对细胞的自发振荡表现出明显的抑制作用；对不表现自发振荡的细胞，咖啡因能引起钙浓度的升高或钙振荡．在无外钙条件下研究连续咖啡因刺激引起的钙浓度变化，发现胞内钙库易排空，但随后的含钙咖啡因刺激仍可引起钙升高．同时，在无外钙条件下施加咖啡因可检测到激素的分泌，表明由咖啡因导致的钙库释放可以独立地触发分泌     

微波萃取-CE-ICP-AES联用分析艾纳香中钙的形态

建立微波萃取-毛细管电泳-电感耦合等离子体原子发射光谱联用方法,用于分析中草药艾纳香中钙元素的形态.研究表明艾纳香中钙以4种形态存在,以标准钙和加标后迁移时间对游离态的钙进行表征,各形态迁移时间RSD＜3％.采用峰面积对艾纳香中各形态钙的含量进行定量,其中游离钙的含量为6.86mg·L-1,钙的加标回收率为97％～102.2％,RSD＜5％.