中国西南部第四纪碳酸钙年代与古环境的地球化学特征

喀斯特地区的泉水和溪流水中沉淀下来的一种次生沉积物，是由碳酸钙过饱和沉淀产生的．碳酸钙沉积或沉积多寡受到多种因素的控制和影响，其中古环境，特别是古气候，影响尤甚．我们通过同位素测年工作，探讨了云贵高原第四纪以来的古环境的演递及其发育历史．     

The plasma membrane calcium pump: Recent developments and future perspectives

The Ca²⁺ pump of the plasma membrane (PMCA) is regulated by a number of agents. The most important is calmodulin (CaM), which binds to a domain located in the C-terminal portion of the pump, removing it from an autoinhibitory site next to the active site. The CaM-binding domain is preceded by an acidic sequence which contains a hidden signal for endoplasmic reticulum (ER) retention. Chimeras of the PMCA and endoplasmic reticulum (SERCA) pumps have revealed the presence of a strong signal for ER retention in the first 45 residues of the SERCA pump. Four gene products of the PMCA pump are known: two of them (1 and 4) are ubiquitously expressed, two (2 and 3) are specific for nerve cells and may be induced by their activation. Mutagenesis work has identified four residues in three of the transmembrane domains of the pump which may be components of the trans-protein Ca²⁺ path. The mutation of two of these residues alters the membrane targeting of the pump.     

黄体酮对离体大鼠胸主动脉条收缩反应的影响

黄体酮（Pro)可使KC1（60mmol/L)或NE（1umol/L)诱发的肌条收缩明显松弛，IC50分别为70.3和93.9(umol/L)；而戊脉安（Ver)的IC50则分别为0.085和0.766(umol/L).Pro和Ver均可使NE或CaCl2引起的肌条收缩量效曲线右移，最大效应降低，呈非竞争性拮抗；Pro的PD2分别为4.072和4.688,Ver的PD2为5.563和6.456。无钙液中加入NE1umol/L引起肌条收缩（1相），再加入CaCl22.5mmol/L引起再次收缩（2相）；Pro可显著抑制上述两种收缩，而Ver仅对2相收缩有显著抑制作用，以上结果表明4；黄体酮有直接扩张血管作用，它与钙拮抗剂戊脉安相似，对电压依赖性钙通道及受体调控性钙通道均有阻滞作用；此外，它还能抑制NE激活的细胞内钙的释放。     

3C_2S·3CaSO_4·CaF_2的性质及其对C_2S与C_3S形成的促进作用

本文对以氟、硫作矿化剂煅烧硅酸盐水泥熟料时出现的过渡相氟硫硅酸钙(3C_2S·3CaSO_4·CaF_2)的性质进行了研究,同时探讨了3CaS·3CaSO_4·Ca F_2对 C_3S 和 C_2S在不同温度及升温速率下的促进作用。     

Cytosolic calcium in platelet activation

Experiments with permeabilised platelets, and with intact platelets loaded with fluorescent Ca²⁺-indicators, over the past several years have greatly extended our knowledge and understanding of cytosolic Ca²⁺ as a platelet activator and its interactions with other cytosolic regulators. This article outlines insights, gained from the use of the fluorescent dyes, into maintenance and restoration of basal [Ca²⁺]_i, mechanisms of receptor-mediated Ca²⁺-mobilisation and quantitation of [Ca²⁺]_i/response relations in intact human platelets.     

A novel pattern of fast calcium oscillations points to calcium and electrical activity cross-talk in rat chromaffin cells

Slow oscillations of cytosolic calcium ion concentration – – typically originate from release by intracellular stores, but in some cell types can be triggered and sustained by Ca²⁺ influx as well. In this study we simultaneously monitored changes in and in the electrical activity of the cell membrane by combining indo-1 and patch-clamp measurements in single rat chromaffin cells. By this approach we observed a novel type of spontaneous oscillations, much faster than those previously described in these cells. These oscillations are triggered and sustained by complex electrical activity (slow action potentials and spike bursts), require Ca²⁺ influx and do not involve release from intracellular stores. The possible physiological implications of this new pathway of intracellular signalling are discussed.Received 30 July 2004; received after revision 14 October 2004; accepted 1 November 2004     

环己烷氨基磺酸钙对叙利亚仓鼠原发性心肌病疗效观察

把BIO FID亚历山在叙利亚仓鼠分成5组,每组40只,雌雄各半,每天分别给予钦含0、275、1 100和2 200 mg/kg的环已烷氨基磺酸钙的水,连续处理90天。这些剂量没有引起动物任何病变,相反,这些动物的原发性心肌病表现出与上述剂量成明显负相关,提示利用环己烷氨基磺酸钙治疗人的某些心肌病值得进一步研究。     

B2O3对磁铁矿烧结过程铁酸钙形成的影响

研究了磁铁矿烧结过程初期液相的形成及加入Ｂ２Ｏ３ 对铁酸钙生成的影响。在磁铁矿烧结过程中,初期液相形成于ＦｅＯｎ－ＣａＯ－ＳｉＯ２系;ＣａＯ溶解于ＦｅＯｎ－ＣａＯ－ＳｉＯ２ 系初期液相,饱和时析出２ＣａＯ·ＳｉＯ２（Ｃ２Ｓ）。在冷却带,由液相中进一步析出Ｃ２Ｓ,同时析出铁酸钙。加入含硼物质可增加铁酸钙的生成量,减少硅酸钙的生成量。