Recent developments in non-excitable cell calcium entry

Cell Calcium ◽  
2001 ◽  
Vol 30 (2) ◽  
pp. 73-93 ◽  
Author(s):  
A.C. Elliott
Keyword(s):  
Calcium Entry ◽  
Excitable Cell ◽  
Cell Calcium ◽  
Recent Developments

scholarly journals The Impact of Vitamin D3Supplementation on Mechanisms of Cell Calcium Signaling in Chronic Kidney Disease

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Ingrid Lajdova ◽  
Viera Spustova ◽  
Adrian Oksa ◽  
Zuzana Kaderjakova ◽  
Dusan Chorvat ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Calcium Signaling ◽  
Calcium Homeostasis ◽  
Calcium Release ◽  
Calcium Entry ◽  
Regulatory Mechanisms ◽  
Cell Calcium ◽  
Crac Channels ◽  
The Impact

Intracellular calcium concentration in peripheral blood mononuclear cells (PBMCs) of patients with chronic kidney disease (CKD) is significantly increased, and the regulatory mechanisms maintaining cellular calcium homeostasis are impaired. The purpose of this study was to examine the effect of vitaminD3on predominant regulatory mechanisms of cell calcium homeostasis. The study involved 16 CKD stages 2-3 patients with vitamin D deficiency treated with cholecalciferol 7000–14000 IU/week for 6 months. The regulatory mechanisms of calcium signaling were studied in PBMCs and red blood cells. After vitaminD3supplementation, serum concentration of 25(OH)D3increased (P<0.001) and[Ca2+]idecreased (P<0.001). The differences in[Ca2+]iwere inversely related to differences in 25(OH)D3concentration (P<0.01). VitaminD3supplementation decreased the calcium entry through calcium release activated calcium (CRAC) channels and purinergic P2X7channels. The function of P2X7receptors was changed in comparison with their baseline status, and the expression of these receptors was reduced. There was no effect of vitaminD3on P2X7pores and activity of plasma membrane Ca2+-ATPases. VitaminD3supplementation had a beneficial effect on[Ca2+]idecreasing calcium entry via CRAC and P2X7channels and reducing P2X7receptors expression.

Expression of polycystin-1 enhances endoplasmic reticulum calcium uptake and decreases capacitative calcium entry in ATP-stimulated MDCK cells

2005 ◽  
Vol 289 (3) ◽  
pp. F521-F530 ◽  
Author(s):  
K. M. Hooper ◽  
A. Boletta ◽  
G. G. Germino ◽  
Q. Hu ◽  
R. C. Ziegelstein ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Calcium Homeostasis ◽  
Mdck Cells ◽  
Fluid Secretion ◽  
Calcium Entry ◽  
Loss Of Function ◽  
Capacitative Calcium Entry ◽  
Endoplasmic Reticulum Calcium ◽  
Cell Calcium ◽  
Er Calcium

Autosomal dominant polycystic kidney disease (ADPKD) types 1 and 2 arise as a consequence of mutations in the PKD1 or PKD2 genes, encoding polycystins-1 and -2. Because loss of function of either of the polycystins leads to a very similar phenotype and the two proteins are known to interact, polycystins-1 and -2 are probably active in the same pathway. The way in which loss of either polycystin leads to the development of ADPKD remains to be established, but disturbances of cell calcium regulation are likely to play an important role. Here, we demonstrate that polycystin-1, heterologously expressed in Madin-Darby canine kidney cells, had a pronounced effect on intracellular calcium homeostasis. ATP-induced calcium responses in transfection control cells exhibited a double peak and relatively gradual return to baseline. By contrast, cells expressing heterologous polycystin-1 showed a brief, uniphasic peak and an accelerated rate of decay. Heterologously expressed polycystin-1 accelerated endoplasmic reticulum (ER) calcium reuptake and inhibited capacitative calcium entry; we found no effect of the protein on mitochondrial calcium buffering or plasma membrane calcium extrusion. We therefore propose that polycystin-1 accelerated the decay of the cell calcium response to ATP by upregulation of ER calcium reuptake and consequent minimization of the stimulus for capacitative calcium entry. It is possible that cellular dedifferentiation, fluid secretion, and proliferation might therefore arise in ADPKD as a consequence of disturbances in cytoplasmic and ER calcium homeostasis and aberrant capacitative calcium entry.

scholarly journals Benzothiazepine CGP37157 and Its Isosteric 2′-Methyl Analogue Provide Neuroprotection and Block Cell Calcium Entry

2012 ◽  
Vol 3 (7) ◽  
pp. 519-529 ◽  
Author(s):  
Laura González-Lafuente ◽  
Javier Egea ◽  
Rafael León ◽  
Francisco J. Martínez-Sanz ◽  
Leticia Monjas ◽  
...  
Keyword(s):  
Calcium Entry ◽  
Cell Calcium

Insulin Inhibits Coronary Endothelial Cell Calcium Entry and Coronary Artery Relaxation

2001 ◽  
Vol 38 (6) ◽  
pp. 885-892 ◽  
Author(s):  
Quang-Kim Tran ◽  
Hiroshi Watanabe ◽  
Hong-Yen Le ◽  
Kazuhiko Takeuchi ◽  
Yuichi Hattori ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Coronary Artery ◽  
Calcium Entry ◽  
Cell Calcium

Trends in Electron Energy Loss Spectroscopy

1977 ◽  
Vol 35 ◽  
pp. 228-229
Author(s):  
C. Colliex ◽  
P. Trebbia
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Materials Science ◽  
Analytical Technique ◽  
Recent Developments ◽  
Quantitative Results ◽  
Electron Microscopes ◽  
Electron Energy Loss ◽  
Primary Electrons

The physical foundations for the use of electron energy loss spectroscopy towards analytical purposes, seem now rather well established and have been extensively discussed through recent publications. In this brief review we intend only to mention most recent developments in this field, which became available to our knowledge. We derive also some lines of discussion to define more clearly the limits of this analytical technique in materials science problems.The spectral information carried in both low ( 0<ΔE<100eV ) and high ( >100eV ) energy regions of the loss spectrum, is capable to provide quantitative results. Spectrometers have therefore been designed to work with all kinds of electron microscopes and to cover large energy ranges for the detection of inelastically scattered electrons (for instance the L-edge of molybdenum at 2500eV has been measured by van Zuylen with primary electrons of 80 kV). It is rather easy to fix a post-specimen magnetic optics on a STEM, but Crewe has recently underlined that great care should be devoted to optimize the collecting power and the energy resolution of the whole system.

Filaments and membranes in the mitotic apparatus

1983 ◽  
Vol 41 ◽  
pp. 544-547
Author(s):  
Kent McDonald
Keyword(s):  
Intermediate Filaments ◽  
Mitotic Spindle ◽  
Mitotic Apparatus ◽  
Light Microscope Level ◽  
Microtubule Associated Proteins ◽  
Recent Developments ◽  
Associated Proteins ◽  
Force Generator ◽  
Spindle Function ◽  
Antibody Technology

At the light microscope level the recent developments and interest in antibody technology have permitted the localization of certain non-microtubule proteins within the mitotic spindle, e.g., calmodulin, actin, intermediate filaments, protein kinases and various microtubule associated proteins. Also, the use of fluorescent probes like chlorotetracycline suggest the presence of membranes in the spindle. Localization of non-microtubule structures in the spindle at the EM level has been less rewarding. Some mitosis researchers, e.g., Rarer, have maintained that actin is involved in mitosis movements though the bulk of evidence argues against this interpretation. Others suggest that a microtrabecular network such as found in chromatophore granule movement might be a possible force generator but there is little evidence for or against this view. At the level of regulation of spindle function, Harris and more recently Hepler have argued for the importance of studying spindle membranes. Hepler also believes that membranes might play a structural or mechanical role in moving chromosomes.

Software pattern recognition applied to nanodiffraction patterns from a STEM instrument

1986 ◽  
Vol 44 ◽  
pp. 694-695
Author(s):  
G.Y. Fan ◽  
J.M. Cowley
Keyword(s):  
Image Processing ◽  
Pattern Recognition ◽  
Computer Software ◽  
Processing System ◽  
Light Level ◽  
Host Computer ◽  
Low Light ◽  
Image Processing System ◽  
Recent Developments ◽  
On Line

In recent developments, the ASU HB5 has been modified so that the timing, positioning, and scanning of the finely focused electron probe can be entirely controlled by a host computer. This made the asynchronized handshake possible between the HB5 STEM and the image processing system which consists of host computer (PDP 11/34), DeAnza image processor (IP 5000) which is interfaced with a low-light level TV camera, array processor (AP 400) and various peripheral devices. This greatly facilitates the pattern recognition technique initiated by Monosmith and Cowley. Software called NANHB5 is under development which, instead of employing a set of photo-diodes to detect strong spots on a TV screen, uses various software techniques including on-line fast Fourier transform (FFT) to recognize patterns of greater complexity, taking advantage of the sophistication of our image processing system and the flexibility of computer software.

High-resolution microscopy of twin boundaries in gold

1987 ◽  
Vol 45 ◽  
pp. 260-261
Author(s):  
William Krakow ◽  
David A. Smith
Keyword(s):  
High Resolution ◽  
Specimen Preparation ◽  
Gold Films ◽  
Boundary Area ◽  
Transmission Electron ◽  
Recent Developments ◽  
Tilt Boundaries ◽  
High Resolution Microscopy ◽  
Twist Boundaries

Recent developments in specimen preparation, imaging and image analysis together permit the experimental determination of the atomic structure of certain, simple grain boundaries in metals such as gold. Single crystal, ∼125Å thick, (110) oriented gold films are vapor deposited onto ∼3000Å of epitaxial silver on (110) oriented cut and polished rock salt substrates. Bicrystal gold films are then made by first removing the silver coated substrate and placing in contact two suitably misoriented pieces of the gold film on a gold grid. Controlled heating in a hot stage first produces twist boundaries which then migrate, so reducing the grain boundary area, to give mixed boundaries and finally tilt boundaries perpendicular to the foil. These specimens are well suited to investigation by high resolution transmission electron microscopy.

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