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Sample records for ca 3075ma ocelli-hosting

  1. Field and geochemical characterisitics of the Mesoarchean (~3075 ma) Ivisaartoq greenstone belt, southern West Greenland: Evidence for seafloor hydrothermal alteration in a supra-subduction oceanic crust

    DEFF Research Database (Denmark)

    Polat, A.; Appel, P.W.U.; Frei, Robert

    2006-01-01

    assemblage is interpreted as relict epidosite. The stage II metasomatic assemblage occurs as concordant discontinuous layered calc-silicate bodies to discordant calc-silicate veins commonly associated with shear zones. The stage II metasomatic assemblage consists mainly of diopside...... + garnet + amphibole + plagioclase + quartz ± vesuvianite ± scapolite ± epidote ± titanite ± calcite ± scheelite. Given that the second stage of metasomatism is closely associated with shear zones and replaced rocks with an early metamorphic fabric, its origin is attributed to regional dynamothermal metamorphism. The least altered pillow basalts, picrites, gabbros, and diorites are characterized by LREE......-enriched, near-flat HREE, and HFSE (especially Nb)-depleted trace element patterns, indicating a subduction zone geochemical signature. Ultramafic pillows and cumulates display large positive initial eNd values of + 1.3 to + 5.0, consistent with a strongly depleted mantle source. Given the geological...

  2. The Ca(2+)/Calmodulin/CaMKK2 Axis: Nature's Metabolic CaMshaft.

    Science.gov (United States)

    Marcelo, Kathrina L; Means, Anthony R; York, Brian

    2016-10-01

    Calcium (Ca(2+)) is an essential ligand that binds its primary intracellular receptor calmodulin (CaM) to trigger a variety of downstream processes and pathways. Central to the actions of Ca(2+)/CaM is the activation of a highly conserved Ca(2+)/CaM kinase (CaMK) cascade that amplifies Ca(2+) signals through a series of subsequent phosphorylation events. Proper regulation of Ca(2+) flux is necessary for whole-body metabolism and disruption of Ca(2+) homeostasis has been linked to various metabolic diseases. Here we provide a synthesis of recent advances that highlight the roles of the Ca(2+)/CaMK axis in key metabolic tissues. An appreciation of this information is critical to understanding the mechanisms by which Ca(2+)/CaM-dependent signaling contributes to metabolic homeostasis and disease.

  3. 有关CA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ 什么是CA? CA(Certificaton Authority)是认证机构的国际通称,是指对数字证书的申请者发放、管理、取消数字证书的机构.CA的作用是检查证书持有者身份的合法性,并签发证书(在证书上签字),以防证书被伪造或篡改.

  4. Topological organization of CA3-to-CA1 excitation.

    Science.gov (United States)

    Hongo, Yoshie; Ogawa, Koichi; Takahara, Yuji; Takasu, Keiko; Royer, Sebastien; Hasegawa, Minoru; Sakaguchi, Gaku; Ikegaya, Yuji

    2015-09-01

    The CA1-projecting axons of CA3 pyramidal cells, called Schaffer collaterals, constitute one of the major information flow routes in the hippocampal formation. Recent anatomical studies have revealed the non-random structural connectivity between CA3 and CA1, but little is known regarding the functional connectivity (i.e. how CA3 network activity is functionally transmitted downstream to the CA1 network). Using functional multi-neuron calcium imaging of rat hippocampal slices, we monitored the spatiotemporal patterns of spontaneous CA3 and CA1 burst activity under pharmacological GABAergic blockade. We found that spatially clustered CA3 activity patterns were transformed into layered CA1 activity sequences. Specifically, synchronized bursts initiated from multiple hot spots in CA3 ensembles, and CA1 neurons located deeper in the pyramidal cell layer were recruited during earlier phases of the burst events. The order of these sequential activations was maintained across the bursts, but the sequence velocity varied depending on the inter-burst intervals. Thus, CA3 axons innervate CA1 neurons in a highly topographical fashion.

  5. Electrodeposition of Ca Metal in CaCl2-CaO Molten Salt

    Institute of Scientific and Technical Information of China (English)

    GUO; Jun-kang; WANG; Chang-shui; CAO; Long-hao; OUYANG; Ying-gen

    2013-01-01

    To realize the continuouscalciothermic reduction in molten salts,the electrodeposition behavior of Ca metal in CaCl2-CaO molten salt was investigated by cylic voltammetry.The cyclic voltammograms at the scan rate of 100 mV/s are shown in Fig.1.As is shown,the electrodeposition potential of Ca deviated from-1.66 V to-0.97 V after CaO was added to molten CaCl2 and the decomposition of CaO

  6. Sulfide capacities of CaO-CaF2-CaCl2 melts

    Science.gov (United States)

    Simeonov, Simeon; Sakai, Toshihiko; Maeda, Masafumi

    1992-06-01

    The sulfide capacityC_{s^{2 - } } = ({text{pct S}}^{{text{2 - }}} )(p_{{text{O}}_{text{2}} } /p_{{text{S}}_{text{2}} } )^{1/2} ) of CaO-CaF2-CaCl2 slag was determined at temperatures from 1000 °C to 1300 °C by equilibrating molten slag, molten silver, and CO-CO2-Ar gas mixture. The sulfide capacity increases with replacing CaCl2 by CaF2 in slags of constant CaO contents. The sulfide capacity also increases with increasing temperature as well as with increasing CaO content at a constant ratio of CaF2/CaCl2 of unity. A linear relationship between the sulfide capacity and carbonate capacity in literature was observed on a logarithmic scale.

  7. Accessing the nuclear symmetry energy in Ca+Ca collisions

    Directory of Open Access Journals (Sweden)

    Chbihi A.

    2012-07-01

    Full Text Available The status of the analysis of the INDRA-VAMOS experiement performed at GANIL, using the reactions 40,48Ca+40,48Ca reactions at 35AMeV, are presented. Isotopic distributions of fragments produced in multifragmentation events provide information on the importance of the surface term contribution in the symmetry energy by comparison to AMD predictions.

  8. Sonoma County, CA, 2013 Lidar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sonoma County Vegetation Mapping and LiDAR Consortium retained WSI to provide lidar and Orthophoto data and derived products in Sonoma County, CA. A classified LAS...

  9. CA125 in ovarian cancer

    DEFF Research Database (Denmark)

    Duffy, M J; Bonfrer, J M; Kulpa, J

    2005-01-01

    value in the detection of early ovarian cancer. At present, therefore, CA125, either alone or in combination with other modalities, cannot be recommended for screening for ovarian cancer in asymptomatic women outside the context of a randomized controlled trial. Preoperative levels in postmenopausal...... women, however, may aid the differentiation of benign and malignant pelvic masses. Serial levels during chemotherapy for ovarian cancer are useful for assessing response to treatment. Although serial monitoring following initial chemotherapy can lead to the early detection of recurrent disease......CA125 is currently the most widely used tumor marker for ovarian epithelial cancer. The aim of this article is to provide guidelines for the routine clinical use of CA125 in patients with ovarian cancer. Due to lack of sensitivity for stage I disease and lack of specificity, CA125 is of little...

  10. Cathodic behavior of molten CaCl2-CaO and CaCl2-NaCl-CaO

    Science.gov (United States)

    Wang, Shu-Lan; Wang, Wei; Li, Shi-Chao; Cao, Shan-Hui

    2010-12-01

    The cathodic behavior of molten CaCl2, CaCl2-CaO and equimolar CaCl2-NaCl-CaO was studied by cyclic voltammograms and constant potential polarization at temperatures of 1123 to 1173 K on molybdenum and titanium electrodes. The diffusion coefficient of Ca2+ (CaO) in molten CaCl2-CaO was calculated from the linear relationship between the square root of scan rate and the peak current density. The deposition potentials and the potential temperature coefficient of CaO in molten CaCl2-0.5mol%CaO and CaCl2-NaCl-0.5mol%CaO were also obtained from their cyclic voltammograms. The result shows that CaO is more easily reduced than CaCl2. The addition of NaCl in molten CaCl2-CaO induces the underpotential electrodeposition of CaO.

  11. CA on CD评析

    Institute of Scientific and Technical Information of China (English)

    周秀会

    2007-01-01

    结合作者使用 CA On CD 的经验和体会,全面而具体地分析了 CA on CD 的使用功能,明确了其优点及不足之处,同时,针对这些不足之处进行了探索和尝试,提出了利用检索技巧解决这些不足之处的方法。并结合实例详细说明。

  12. The site of net absorption of Ca from the intestinal tract of growing pigs and effect of phytic acid, Ca level and Ca source on Ca digestibility.

    Science.gov (United States)

    González-Vega, J Caroline; Walk, Carrie L; Liu, Yanhong; Stein, Hans H

    2014-01-01

    An experiment was conducted to test the hypothesis that the standardised digestibility of Ca in calcium carbonate and Lithothamnium calcareum Ca is not different regardless of the level of dietary Ca, and that phytic acid affects the digestibility of Ca in these two ingredients to the same degree. The objectives were to determine where in the intestinal tract Ca absorption takes place and if there are measurable quantities of basal endogenous Ca fluxes in the stomach, small intestine or large intestine. Diets contained calcium carbonate or L. calcareum Ca as the sole source of Ca, 0% or 1% phytic acid and 0.4% or 0.8% Ca. A Ca-free diet was also formulated and used to measure endogenous fluxes and losses of Ca. Nine growing pigs (initial body weight 23.8 ± 1.3 kg) were cannulated in the duodenum and in the distal ileum, and faecal, ileal and duodenal samples were collected. Duodenal endogenous fluxes of Ca were greater (p phytic acid, but decreased (p phytic acid, but may be affected by dietary Ca level depending on the Ca source. Calcium from calcium carbonate is mostly absorbed before the duodenum, but Ca from L. calcareum Ca is mostly absorbed in the jejunum and ileum.

  13. The diagnostic value of joint detection of serum CA19-9, CA125 and CA242 for cholangiocarcinoma

    Institute of Scientific and Technical Information of China (English)

    Cui Da-Peng; Han Lei; Liu Zhen-Xian; Yang He; Zhang Ying-Chun

    2016-01-01

    Objective:To study the diagnostic value of joint detection of serum CA19-9, CA125 and CA242 for cholangiocarcinoma.Methods:A total of 35 patients with cholangiocarcinoma who received surgical resection in our hospital were selected as malignant group, 30 patients with cholelithiasis who received surgical resection in our hospital during the same period were selected as benign group, serum samples were collected before surgery to determine CA19-9, CA125 and CA242 content, and cholangiocarcinoma tissue and normal bile duct tissue were collected after surgery to determine the content of proliferation and invasion molecules. Results:Serum CA19-9, CA125 and CA242 levels of malignant group were significantly higher than those of control group; PROX-1, Ki-67, Bcl-2, Bad, Gab1, LOXL2, TRPM7 and CXCL12 levels in cholangiocarcinoma tissue were higher than those in benign bile duct tissue, and E-cadherin level was lower than that in benign bile duct tissue; serum CA19-9, CA125 and CA242 levels were positively correlated with PROX-1, Ki-67, Bcl-2, Bad, Gab1, LOXL2, TRPM7 and CXCL12 levels, and negatively correlated with E-cadherin level.Conclusion:Joint detection of serum CA19-9, CA125 and CA242 can not only provide reference for the diagnosis of cholangiocarcinoma, but can also provide basis for the evaluation of proliferation, invasion and other malignant biological behaviors.

  14. Isotopic Effects on Stereodynamics for Ca+HCI, Ca+DCI, and Ca+TClReactions

    Institute of Scientific and Technical Information of China (English)

    Li-zhi Wang; Chuan-lu Yang; Jing-juan Liang; Jing Xiao; Qing-gang Zhang

    2011-01-01

    The vector correlations in Ca+HC1,Ca+DCI,and Ca+TCI reactions have been investigated by means of the quasi-classical trajectory calculations on PES constructed by means of multireference configuration interaction.The distributions of P(θr),P(Φr) and the PDDCSs of (2π/σ)(dσ00/dωt),(2π/σ)(dσ20/dωt),(2π/σ)(dσ22+/dωt),(2π/σ)(dσ21-/dωt) have been calculated based on the surface.The remarkable isotopic effects in the reactions are observed,and the mechanism which may be ascribed to different mass factors is discussed.

  15. Solar Ca II K Observations

    Science.gov (United States)

    Bertello, Luca; Pevtsov, Alexei A.; Tlatov, Andrey; Singh, Jagdev

    2016-07-01

    Some of the most important archives of past and current long-term solar synoptic observations in the resonance line of Ca II K are described here. These observations are very important for understanding the state of the solar magnetism on time scales up to several decades. The first observations of this kind began in 1904 at the Kodaikanal Observatory (India), followed by similar programs at different other locations. Regular full-disk Ca II K monitoring programs started in 1915 at the Mount Wilson Observatory (USA) and in 1917 at the National Solar Observatory of Japan. Beginning in 1919 and in 1926 regular observations were taken also at the Paris-Meudon Observatory (France) and at the "Donati solar tower telescope of the Arcetri Astrophysical Observatory in Italy, respectively. In 1926 the the Astronomical Observatory of the Coimbra University in Portugal started its own program of Ca II K observations. Although some of these programs have been terminated over the years, their data archives constitute a unique resource for studies of solar variability. In the early 1970s, the National Solar Observatory (NSO) at Sacramento Peak (USA) started a new program of daily Sun-as-a-star observations in the Ca II K line. Today the NSO is continuing these observations through its Synoptic Optical Long-term Investigations of the Sun (SOLIS) facility.

  16. EMRE Is a Matrix Ca(2+) Sensor that Governs Gatekeeping of the Mitochondrial Ca(2+) Uniporter.

    Science.gov (United States)

    Vais, Horia; Mallilankaraman, Karthik; Mak, Don-On Daniel; Hoff, Henry; Payne, Riley; Tanis, Jessica E; Foskett, J Kevin

    2016-01-26

    The mitochondrial uniporter (MCU) is an ion channel that mediates Ca(2+) uptake into the matrix to regulate metabolism, cell death, and cytoplasmic Ca(2+) signaling. Matrix Ca(2+) concentration is similar to that in cytoplasm, despite an enormous driving force for entry, but the mechanisms that prevent mitochondrial Ca(2+) overload are unclear. Here, we show that MCU channel activity is governed by matrix Ca(2+) concentration through EMRE. Deletion or charge neutralization of its matrix-localized acidic C terminus abolishes matrix Ca(2+) inhibition of MCU Ca(2+) currents, resulting in MCU channel activation, enhanced mitochondrial Ca(2+) uptake, and constitutively elevated matrix Ca(2+) concentration. EMRE-dependent regulation of MCU channel activity requires intermembrane space-localized MICU1, MICU2, and cytoplasmic Ca(2+). Thus, mitochondria are protected from Ca(2+) depletion and Ca(2+) overload by a unique molecular complex that involves Ca(2+) sensors on both sides of the inner mitochondrial membrane, coupled through EMRE.

  17. KWU-werkersklasdramas in Afrikaans (ca. 1930 - ca. 1950

    Directory of Open Access Journals (Sweden)

    J. L. Coetser

    1999-05-01

    Full Text Available GWU working class theatre in Afrikaans (ca. 1930 - ca. 1950In 1984 Elsabé Brink drew attention to plays, prose and poetry written between 1930 and 1950 in Afrikaans by members of the Garment Workers’ Union (GWU. Scholars such as Stander and Willemse (1992, Van Niekerk (1996 and Van Wyk (1995, 1997 have also referred to GWU plays. Apart from these overviews, GWU plays as such have not yet received the attention they deserve. This article presents a revaluation, initially by providing an overview of their contents, followed by an examination of cultural, economic and political influences. It is argued that - retrospectively - the GWU plays reflected a unique cultural specificity from the framework established by Sitas (1986 for more contemporary working class theatre.

  18. Ca2+ dynamics in zebrafish morphogenesis

    Directory of Open Access Journals (Sweden)

    Yusuke Tsuruwaka

    2017-01-01

    Full Text Available Intracellular calcium ion (Ca2+ signaling is heavily involved in development, as illustrated by the use of a number of Ca2+ indicators. However, continuous Ca2+ patterns during morphogenesis have not yet been studied using fluorescence resonance energy transfer to track the Ca2+ sensor. In the present study, we monitored Ca2+ levels during zebrafish morphogenesis and differentiation with yellow cameleon, YC2.12. Our results show not only clear changes in Ca2+ levels but also continuous Ca2+ patterns at 24 hpf and later periods for the first time. Serial Ca2+dynamics during early pharyngula period (Prim-5-20; 24–33 hpf was successfully observed with cameleon, which have not reported anywhere yet. In fact, high Ca2+ level occurred concurrently with hindbrain development in segmentation and pharyngula periods. Ca2+ patterns in the late gastrula through segmentation periods which were obtained with cameleon, were similar to those obtained previously with other Ca2+sensor. Our results suggested that the use of various Ca2+ sensors may lead to novel findings in studies of Ca2+ dynamics. We hope that these results will prove valuable for further research in Ca2+ signaling.

  19. Lattice Dynamics of fcc Ca

    DEFF Research Database (Denmark)

    Stassis, C.; Zaretsky, J.; Misemer, D. K.;;

    1983-01-01

    to the propagation of elastic waves. The frequencies of the T1[ξξ0] branch for ξ between approximately 0.5 and 0.8 are slightly above the velocity-of-sound line determined from the low-frequency measurements. Since a similar effect has been observed in FCC Yb, it is natural to assume that the anomalous dispersion......A large single crystal of FCC Ca was grown and was used to study the lattice dynamics of this divalent metal by coherent inelastic neutron scattering. The phonon dispersion curves were measured, at room temperature, along the [ξ00], [ξξ0], [ξξξ], and [0ξ1] symmetry directions. The dispersion curves...... bear a striking resemblance to those of FCC Yb, which is also a divalent metal with an electronic band structure similar to that of Ca. In particular, the shear moduli c44 and (c11-c 12)/2 differ by a factor of 3.4, which implies that FCC Ca (like FCC Yb) is very anisotropic with regard...

  20. Fine tuning of cytosolic Ca 2+ oscillations

    Science.gov (United States)

    Dupont, Geneviève; Combettes, Laurent

    2016-01-01

    Ca 2+ oscillations, a widespread mode of cell signaling, were reported in non-excitable cells for the first time more than 25 years ago. Their fundamental mechanism, based on the periodic Ca 2+ exchange between the endoplasmic reticulum and the cytoplasm, has been well characterized. However, how the kinetics of cytosolic Ca 2+ changes are related to the extent of a physiological response remains poorly understood. Here, we review data suggesting that the downstream targets of Ca 2+ are controlled not only by the frequency of Ca 2+ oscillations but also by the detailed characteristics of the oscillations, such as their duration, shape, or baseline level. Involvement of non-endoplasmic reticulum Ca 2+ stores, mainly mitochondria and the extracellular medium, participates in this fine tuning of Ca 2+ oscillations. The main characteristics of the Ca 2+ exchange fluxes with these compartments are also reviewed. PMID:27630768

  1. [Effect of polycarbophil Ca on IBS].

    Science.gov (United States)

    Mine, Tetsuya

    2006-08-01

    In this chapter, I mentioned the effect of polycarbophil Ca on IBS. IBS is classified into 3 types; diarrhea type, constipation type and combined type. Polycarbophil Ca is effective for all types of IBS.

  2. Barnacle muscle: Ca2+, activation and mechanics.

    Science.gov (United States)

    Ashley, C C; Griffiths, P J; Lea, T J; Mulligan, I P; Palmer, R E; Simnett, S J

    1993-01-01

    In this review, aspects of the ways in which Ca2+ is transported and regulated within muscle cells have been considered, with particular reference to crustacean muscle fibres. The large size of these fibres permits easy access to the internal environment of the cell, allowing it to be altered by microinjection or microperfusion. At rest, Ca2+ is not in equilibrium across the cell membrane, it enters the cell down a steep electrochemical gradient. The free [Ca2+] at rest is maintained at a value close to 200 nM by a combination of internal buffering systems, mainly the SR, mitochondria, and the fixed and diffusible Ca(2+)-binding proteins, as well as by an energy-dependent extrusion system operating across the external cell membrane. This system relies upon the inward movement of Na+ down its own electrochemical gradient to provide the energy for the extrusion of Ca2+ ions. As a result of electrical excitation, voltage-sensitive channels for Ca2+ are activated and permit Ca2+ to enter the cell more rapidly than at rest. It has been possible to determine both the amount of Ca2+ entering by this step, and what part this externally derived Ca2+ plays in the development of force as well as in the free Ca2+ change. The latter can be determined directly by Ca(2+)-sensitive indicators introduced into the cell sarcoplasm. A combination of techniques, allowing both the total and free Ca2+ changes to be assessed during electrical excitation, has provided valuable information as to how muscle cells buffer their Ca2+ in order to regulate the extent of the change in the free Ca2+ concentration. The data indicate that the entering Ca2+ can only make a small direct contribution to the force developed by the cell. The implication here is that the major source of Ca2+ for contraction must be derived from the internal Ca2+ storage sites within the SR system, a view reinforced by caged Ca2+ methods. The ability to measure the free Ca2+ concentration changes within a single cell during

  3. CA-CA互操作研究%Research of CA-CA Interoperability

    Institute of Scientific and Technical Information of China (English)

    沈士根; 叶培松; 陈宝明

    2005-01-01

    文章介绍了国际上CA-CA之间实现互操作的信任模式,然后根据中国目前的PKI实际情况,提出了以桥CA为全局模式,局部可采用严格层次信任模式来实现各CA之间的互操作.

  4. Altered network timing in the CA3-CA1 circuit of hippocampal slices from aged mice.

    Directory of Open Access Journals (Sweden)

    Daniel J Kanak

    Full Text Available Network patterns are believed to provide unique temporal contexts for coordinating neuronal activity within and across different regions of the brain. Some of the characteristics of network patterns modeled in vitro are altered in the CA3 or CA1 subregions of hippocampal slices from aged mice. CA3-CA1 network interactions have not been examined previously. We used slices from aged and adult mice to model spontaneous sharp wave ripples and carbachol-induced gamma oscillations, and compared measures of CA3-CA1 network timing between age groups. Coherent sharp wave ripples and gamma oscillations were evident in the CA3-CA1 circuit in both age groups, but the relative timing of activity in CA1 stratum pyramidale was delayed in the aged. In another sample of aged slices, evoked Schaffer collateral responses were attenuated in CA3 (antidromic spike amplitude and CA1 (orthodromic field EPSP slope. However, the amplitude and timing of spontaneous sharp waves recorded in CA1 stratum radiatum were similar to adults. In both age groups unit activity recorded juxtacellularly from unidentified neurons in CA1 stratum pyramidale and stratum oriens was temporally modulated by CA3 ripples. However, aged neurons exhibited reduced spike probability during the early cycles of the CA3 ripple oscillation. These findings suggest that aging disrupts the coordination of patterned activity in the CA3-CA1 circuit.

  5. An inhibitory effect of extracellular Ca2+ on Ca2+-dependent exocytosis.

    Directory of Open Access Journals (Sweden)

    Wei Xiong

    Full Text Available AIM: Neurotransmitter release is elicited by an elevation of intracellular Ca(2+ concentration ([Ca(2+](i. The action potential triggers Ca(2+ influx through Ca(2+ channels which causes local changes of [Ca(2+](i for vesicle release. However, any direct role of extracellular Ca(2+ (besides Ca(2+ influx on Ca(2+-dependent exocytosis remains elusive. Here we set out to investigate this possibility on rat dorsal root ganglion (DRG neurons and chromaffin cells, widely used models for studying vesicle exocytosis. RESULTS: Using photolysis of caged Ca(2+ and caffeine-induced release of stored Ca(2+, we found that extracellular Ca(2+ inhibited exocytosis following moderate [Ca(2+](i rises (2-3 µM. The IC(50 for extracellular Ca(2+ inhibition of exocytosis (ECIE was 1.38 mM and a physiological reduction (∼30% of extracellular Ca(2+ concentration ([Ca(2+](o significantly increased the evoked exocytosis. At the single vesicle level, quantal size and release frequency were also altered by physiological [Ca(2+](o. The calcimimetics Mg(2+, Cd(2+, G418, and neomycin all inhibited exocytosis. The extracellular Ca(2+-sensing receptor (CaSR was not involved because specific drugs and knockdown of CaSR in DRG neurons did not affect ECIE. CONCLUSION/SIGNIFICANCE: As an extension of the classic Ca(2+ hypothesis of synaptic release, physiological levels of extracellular Ca(2+ play dual roles in evoked exocytosis by providing a source of Ca(2+ influx, and by directly regulating quantal size and release probability in neuronal cells.

  6. 46 CFR 7.130 - Point Conception, CA to Point Sur, CA.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Point Conception, CA to Point Sur, CA. 7.130 Section 7.130 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC BOUNDARY LINES Pacific Coast § 7.130 Point Conception, CA to Point Sur, CA. (a) A line drawn from...

  7. Testing coral paleothermometers (B/Ca, Mg/Ca, Sr/Ca, U/Ca andδ18O) under impacts of large riverine runoff

    Institute of Scientific and Technical Information of China (English)

    CHEN Tianran; YU Kefu; ZHAO Jianxin; YAN Hongqiang; SONG Yinxian; FENG Yuexing; CHEN Tegu

    2015-01-01

    Sea surface temperature (SST) proxies including B/Ca, Mg/Ca, Sr/Ca, U/Ca andδ18O were analyzed in the skeleton of aPorites coral collected from the Zhujiang River (Pearl River) Estuary (ZRE). These geochemical proxies are influenced by river runoff and this area of the northern South China Sea is strongly affected by seasonal freshwater floods. We assessed the robustness of each SST proxy through comparison with the local instrumental SST. Coral Sr/Ca shows the highest correlation with SST variations (r2=0.59), suggesting Sr/Ca is the most robust SST proxy. In contrast, coralδ18O (r2=0.46), B/Ca (r2=0.43) and U/Ca (r2=0.41) ratios were only moderately correlated with SST variations, suggesting that they are disturbed by some other factors in addition to SST. The poor correlation (r2=0.27) between SST and Mg/Ca indicates that Mg/Ca in coral skeletons is not a simple function of SST variations. This may ultimately limit the use of Mg/Ca as a coral paleothermometer.

  8. Multiple Ca2+ sensors in secretion

    DEFF Research Database (Denmark)

    Walter, Alexander M; Groffen, Alexander J; Sørensen, Jakob Balslev;

    2011-01-01

    Regulated neurotransmitter secretion depends on Ca(2+) sensors, C2 domain proteins that associate with phospholipids and soluble N-ethylmaleimide-sensitive fusion attachment protein receptor (SNARE) complexes to trigger release upon Ca(2+) binding. Ca(2+) sensors are thought to prevent spontaneous...... fusion at rest (clamping) and to promote fusion upon Ca(2+) activation. At least eight, often coexpressed, Ca(2+) sensors have been identified in mammals. Accumulating evidence suggests that multiple Ca(2+) sensors interact, rather than work autonomously, to produce the complex secretory response...... observed in neurons and secretory cells. In this review, we present several working models to describe how different sensors might be arranged to mediate synchronous, asynchronous and spontaneous neurotransmitter release. We discuss the scenario that different Ca(2+) sensors typically act on one shared...

  9. Autonomous CaMKII requires further stimulation by Ca2+/calmodulin for enhancing synaptic strength.

    Science.gov (United States)

    Barcomb, Kelsey; Buard, Isabelle; Coultrap, Steven J; Kulbe, Jacqueline R; O'Leary, Heather; Benke, Timothy A; Bayer, K Ulrich

    2014-08-01

    A hallmark feature of Ca(2+)/calmodulin (CaM)-dependent protein kinase II (CaMKII) is generation of autonomous (Ca(2+)-independent) activity by T286 autophosphorylation. Biochemical studies have shown that "autonomous" CaMKII is ∼5-fold further stimulated by Ca(2+)/CaM, but demonstration of a physiological function for such regulation within cells has remained elusive. In this study, CaMKII-induced enhancement of synaptic strength in rat hippocampal neurons required both autonomous activity and further stimulation. Synaptic strength was decreased by CaMKIIα knockdown and rescued by reexpression, but not by mutants impaired for autonomy (T286A) or binding to NMDA-type glutamate receptor subunit 2B (GluN2B; formerly NR2B; I205K). Full rescue was seen with constitutively autonomous mutants (T286D), but only if they could be further stimulated (additional T305/306A mutation), and not with two other mutations that additionally impair Ca(2+)/CaM binding. Compared to rescue with wild-type CaMKII, the CaM-binding-impaired mutants even had reduced synaptic strength. One of these mutants (T305/306D) mimicked an inhibitory autophosphorylation of CaMKII, whereas the other one (Δstim) abolished CaM binding without introducing charged residues. Inhibitory T305/306 autophosphorylation also reduced GluN2B binding, but this effect was independent of reduced Ca(2+)/CaM binding and was not mimicked by T305/306D mutation. Thus, even autonomous CaMKII activity must be further stimulated by Ca(2+)/CaM for enhancement of synaptic strength.

  10. Influence of NaCl-CaCl2 on Decomposing REPO4 with CaO

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The influence of NaCl-CaCl2 on thermal decomposition of REPO4 (RE: Ce, La, Nd, Th) with CaO was studied.The heat decomposing process of REPO4 was tested with TG-DTA experiments.The results showed that the decomposition temperature of REPO4 with CaO was reduced because of adding NaCl-CaCl2 mixture (NaCl:CaCl2=1:1).The influence of the addition of NaCl-CaCl2, roasting temperature and roasting time on decomposition ratio of REPO4 with CaO was studied.The results showed that the decomposition ratio of REPO4with CaO was 79% when the addition percentage of NaCl-CaCl2 was 10%, the roasting temperature was 750℃, and the roasting time was 1 h.

  11. Involvement of Ca2+/CaM in the signal transduction of acetylcholine regulating stomatal movement

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    It has been known that the neurotransmitter acetylcholine (ACh) also exists in plants and is able to regulate the movement of stomata. In another aspect, Ca2+/CaM as the second messengers have a critical role of signal transduction in stomatal guard-cell. Here we showed that Ca2+/CaM were also involved in theACh regulated stomatal movement. In the medium containing Ca2+, the Ca2+ channel blockers (NIF and Ver) and CaM inhibitors (TFP and W7) could neutralize the ACh induced stomatal opening, however, they are ineffective in the medium containing K+. Those results indicated that Ca2+/CaM were involved in the signal transduction pathway of ACh regulating stomatal movement.

  12. Ca2+ cycling in heart cells from ground squirrels: adaptive strategies for intracellular Ca2+ homeostasis.

    Directory of Open Access Journals (Sweden)

    Xiao-Chen Li

    Full Text Available Heart tissues from hibernating mammals, such as ground squirrels, are able to endure hypothermia, hypoxia and other extreme insulting factors that are fatal for human and nonhibernating mammals. This study was designed to understand adaptive mechanisms involved in intracellular Ca(2+ homeostasis in cardiomyocytes from the mammalian hibernator, ground squirrel, compared to rat. Electrophysiological and confocal imaging experiments showed that the voltage-dependence of L-type Ca(2+ current (I(Ca was shifted to higher potentials in ventricular myocytes from ground squirrels vs. rats. The elevated threshold of I(Ca did not compromise the Ca(2+-induced Ca(2+ release, because a higher depolarization rate and a longer duration of action potential compensated the voltage shift of I(Ca. Both the caffeine-sensitive and caffeine-resistant components of cytosolic Ca(2+ removal were more rapid in ground squirrels. Ca(2+ sparks in ground squirrels exhibited larger amplitude/size and much lower frequency than in rats. Due to the high I(Ca threshold, low SR Ca(2+ leak and rapid cytosolic Ca(2+ clearance, heart cells from ground squirrels exhibited better capability in maintaining intracellular Ca(2+ homeostasis than those from rats and other nonhibernating mammals. These findings not only reveal adaptive mechanisms of hibernation, but also provide novel strategies against Ca(2+ overload-related heart diseases.

  13. γCaMKII shuttles Ca²⁺/CaM to the nucleus to trigger CREB phosphorylation and gene expression.

    Science.gov (United States)

    Ma, Huan; Groth, Rachel D; Cohen, Samuel M; Emery, John F; Li, Boxing; Hoedt, Esthelle; Zhang, Guoan; Neubert, Thomas A; Tsien, Richard W

    2014-10-09

    Activity-dependent CREB phosphorylation and gene expression are critical for long-term neuronal plasticity. Local signaling at CaV1 channels triggers these events, but how information is relayed onward to the nucleus remains unclear. Here, we report a mechanism that mediates long-distance communication within cells: a shuttle that transports Ca(2+)/calmodulin from the surface membrane to the nucleus. We show that the shuttle protein is γCaMKII, its phosphorylation at Thr287 by βCaMKII protects the Ca(2+)/CaM signal, and CaN triggers its nuclear translocation. Both βCaMKII and CaN act in close proximity to CaV1 channels, supporting their dominance, whereas γCaMKII operates as a carrier, not as a kinase. Upon arrival within the nucleus, Ca(2+)/CaM activates CaMKK and its substrate CaMKIV, the CREB kinase. This mechanism resolves long-standing puzzles about CaM/CaMK-dependent signaling to the nucleus. The significance of the mechanism is emphasized by dysregulation of CaV1, γCaMKII, βCaMKII, and CaN in multiple neuropsychiatric disorders.

  14. Dissection of local Ca(2+) signals inside cytosol by ER-targeted Ca(2+) indicator.

    Science.gov (United States)

    Niwa, Fumihiro; Sakuragi, Shigeo; Kobayashi, Ayana; Takagi, Shin; Oda, Yoichi; Bannai, Hiroko; Mikoshiba, Katsuhiko

    2016-10-07

    Calcium (Ca(2+)) is a versatile intracellular second messenger that operates in various signaling pathways leading to multiple biological outputs. The diversity of spatiotemporal patterns of Ca(2+) signals, generated by the coordination of Ca(2+) influx from the extracellular space and Ca(2+) release from the intracellular Ca(2+) store the endoplasmic reticulum (ER), is considered to underlie the diversity of biological outputs caused by a single signaling molecule. However, such Ca(2+) signaling diversity has not been well described because of technical limitations. Here, we describe a new method to report Ca(2+) signals at subcellular resolution. We report that OER-GCaMP6f, a genetically encoded Ca(2+) indicator (GECI) targeted to the outer ER membrane, can monitor Ca(2+) release from the ER at higher spatiotemporal resolution than conventional GCaMP6f. OER-GCaMP6f was used for in vivo Ca(2+) imaging of C. elegans. We also found that the spontaneous Ca(2+) elevation in cultured astrocytes reported by OER-GCaMP6f showed a distinct spatiotemporal pattern from that monitored by plasma membrane-targeted GCaMP6f (Lck-GCaMP6f); less frequent Ca(2+) signal was detected by OER-GCaMP6f, in spite of the fact that Ca(2+) release from the ER plays important roles in astrocytes. These findings suggest that targeting of GECIs to the ER outer membrane enables sensitive detection of Ca(2+) release from the ER at subcellular resolution, avoiding the diffusion of GECI and Ca(2+). Our results indicate that Ca(2+) imaging with OER-GCaMP6f in combination with Lck-GCaMP6f can contribute to describing the diversity of Ca(2+) signals, by enabling dissection of Ca(2+) signals at subcellular resolution.

  15. Interlamellar CA1 network in the hippocampus

    OpenAIRE

    Yang, Sunggu; Yang, Sungchil; Moreira, Thais; Hoffman, Gloria; Carlson, Greg C.; Bender, Kevin J.; Alger, Bradley E.; Tang, Cha-Min

    2014-01-01

    It has generally been thought that CA1 cells form only negligible connections with each other along the longitudinal axis of the hippocampus. But if CA1 cells were interconnected in an effective autoassociational network, this information would add a critical new dimension to our understanding of cellular processing within this structure. Here, we report the existence of a well-organized, longitudinally projecting synaptic network among CA1 pyramidal neurons. We further show that synapses of ...

  16. Localized Calcineurin Confers Ca2+-Dependent Inactivation Upon Neuronal L-Type Ca2+ Channels

    OpenAIRE

    2012-01-01

    Excitation-driven entry of Ca2+ through L-type voltage-gated Ca2+ channels controls gene expression in neurons and a variety of fundamental activities in other kinds of excitable cells. The probability of opening of CaV1.2 L-type channels is subject to pronounced enhancement by cAMP-dependent protein kinase (PKA), which is scaffolded to CaV1.2 channels by A-kinase anchoring proteins (AKAPs). CaV1.2 channels also undergo negative autoregulation via Ca2+-dependent inactivation (CDI), which stro...

  17. Glutamate excitotoxicity and Ca2+-regulation of respiration: Role of the Ca2+ activated mitochondrial transporters (CaMCs).

    Science.gov (United States)

    Rueda, Carlos B; Llorente-Folch, Irene; Traba, Javier; Amigo, Ignacio; Gonzalez-Sanchez, Paloma; Contreras, Laura; Juaristi, Inés; Martinez-Valero, Paula; Pardo, Beatriz; Del Arco, Araceli; Satrustegui, Jorgina

    2016-08-01

    Glutamate elicits Ca(2+) signals and workloads that regulate neuronal fate both in physiological and pathological circumstances. Oxidative phosphorylation is required in order to respond to the metabolic challenge caused by glutamate. In response to physiological glutamate signals, cytosolic Ca(2+) activates respiration by stimulation of the NADH malate-aspartate shuttle through Ca(2+)-binding to the mitochondrial aspartate/glutamate carrier (Aralar/AGC1/Slc25a12), and by stimulation of adenine nucleotide uptake through Ca(2+) binding to the mitochondrial ATP-Mg/Pi carrier (SCaMC-3/Slc25a23). In addition, after Ca(2+) entry into the matrix through the mitochondrial Ca(2+) uniporter (MCU), it activates mitochondrial dehydrogenases. In response to pathological glutamate stimulation during excitotoxicity, Ca(2+) overload, reactive oxygen species (ROS), mitochondrial dysfunction and delayed Ca(2+) deregulation (DCD) lead to neuronal death. Glutamate-induced respiratory stimulation is rapidly inactivated through a mechanism involving Poly (ADP-ribose) Polymerase-1 (PARP-1) activation, consumption of cytosolic NAD(+), a decrease in matrix ATP and restricted substrate supply. Glutamate-induced Ca(2+)-activation of SCaMC-3 imports adenine nucleotides into mitochondria, counteracting the depletion of matrix ATP and the impaired respiration, while Aralar-dependent lactate metabolism prevents substrate exhaustion. A second mechanism induced by excitotoxic glutamate is permeability transition pore (PTP) opening, which critically depends on ROS production and matrix Ca(2+) entry through the MCU. By increasing matrix content of adenine nucleotides, SCaMC-3 activity protects against glutamate-induced PTP opening and lowers matrix free Ca(2+), resulting in protracted appearance of DCD and protection against excitotoxicity in vitro and in vivo, while the lack of lactate protection during in vivo excitotoxicity explains increased vulnerability to kainite-induced toxicity in Aralar

  18. The initial 41Ca/40Ca ratios in two type A Ca-Al-rich inclusions: Implications for the origin of short-lived 41Ca

    Science.gov (United States)

    Liu, Ming-Chang

    2017-03-01

    This paper reports new 41Ca-41K isotopic data for two Type A CAIs, NWA 3118 #1Nb (Compact Type A) and Vigarano 3138 F8 (Fluffy Type A), from reduced CV3 chondrites. The NWA CAI is found to have carried live 41Ca at the level of (4.6 ± 1.9) ×10-9 , consistent with the proposed Solar System initial 41Ca /40Ca = 4.2 ×10-9 by Liu et al. (2012a). On the other hand, the Vigarano CAI does not have resolvable radiogenic 41K excesses that can be attributed to the decay of 41Ca. Combined with the 26Al data that have been reported for these two CAIs, we infer that the 41Ca distribution was not homogeneous when 26Al was widespread at the canonical level of 26Al /27Al = 5.2 ×10-5 . Such a 41Ca heterogeneity can be understood under two astrophysical contexts: in situ charged particle irradiation by the protoSun in the solar nebula that had inherited some baseline 10Be abundance from the molecular cloud, and Solar System formation in a molecular cloud enriched in 26Al and 41Ca contaminated by massive star winds. That said, more high quality 41Ca data are still needed to better understand the origin of this radionuclide.

  19. Supralinear dendritic Ca(2+) signalling in young developing CA1 pyramidal cells.

    Science.gov (United States)

    Pohle, Jörg; Bischofberger, Josef

    2014-11-15

    Although Ca(2+) is critically important in activity-dependent neuronal development, not much is known about the regulation of dendritic Ca(2+) signals in developing neurons. Here, we used ratiometric Ca(2+) imaging to investigate dendritic Ca(2+) signalling in rat hippocampal pyramidal cells during the first 1-4 weeks of postnatal development. We show that active dendritic backpropagation of Nav channel-dependent action potentials (APs) evoked already large dendritic Ca(2+) transients in animals aged 1 week with amplitudes of ∼150 nm, similar to the amplitudes of ∼160 nM seen in animals aged 4 weeks. Although the AP-evoked dendritic Ca(2+) load increased about four times during the first 4 weeks, the peak amplitude of free Ca(2+) concentration was balanced by a four-fold increase in Ca(2+) buffer capacity κs (∼70 vs. ∼280). Furthermore, Ca(2+) extrusion rates increased with postnatal development, leading to a slower decay time course (∼0.2 s vs. ∼0.1 s) and more effective temporal summation of Ca(2+) signals in young cells. Most importantly, during prolonged theta-burst stimulation dendritic Ca(2+) signals were up to three times larger in cells at 1 week than at 4 weeks of age and much larger than predicted by linear summation, which is attributable to an activity-dependent slow-down of Ca(2+) extrusion. As Ca(2+) influx is four-fold smaller in young cells, the larger Ca(2+) signals are generated using four times less ATP consumption. Taken together, the data suggest that active backpropagations regulate dendritic Ca(2+) signals during early postnatal development. Remarkably, during prolonged AP firing, Ca(2+) signals are several times larger in young than in mature cells as a result of activity-dependent regulation of Ca(2+) extrusion rates.

  20. EMRE Is a Matrix Ca2+ Sensor that Governs Gatekeeping of the Mitochondrial Ca2+ Uniporter

    Directory of Open Access Journals (Sweden)

    Horia Vais

    2016-01-01

    Full Text Available The mitochondrial uniporter (MCU is an ion channel that mediates Ca2+ uptake into the matrix to regulate metabolism, cell death, and cytoplasmic Ca2+ signaling. Matrix Ca2+ concentration is similar to that in cytoplasm, despite an enormous driving force for entry, but the mechanisms that prevent mitochondrial Ca2+ overload are unclear. Here, we show that MCU channel activity is governed by matrix Ca2+ concentration through EMRE. Deletion or charge neutralization of its matrix-localized acidic C terminus abolishes matrix Ca2+ inhibition of MCU Ca2+ currents, resulting in MCU channel activation, enhanced mitochondrial Ca2+ uptake, and constitutively elevated matrix Ca2+ concentration. EMRE-dependent regulation of MCU channel activity requires intermembrane space-localized MICU1, MICU2, and cytoplasmic Ca2+. Thus, mitochondria are protected from Ca2+ depletion and Ca2+ overload by a unique molecular complex that involves Ca2+ sensors on both sides of the inner mitochondrial membrane, coupled through EMRE.

  1. Biphasic decay of the Ca transient results from increased sarcoplasmic reticulum Ca leak

    Science.gov (United States)

    Sankaranarayanan, Rajiv; Li, Yatong; Greensmith, David J.; Eisner, David A.

    2016-01-01

    Key points Ca leak from the sarcoplasmic reticulum through the ryanodine receptor (RyR) reduces the amplitude of the Ca transient and slows its rate of decay.In the presence of β‐adrenergic stimulation, RyR‐mediated Ca leak produces a biphasic decay of the Ca transient with a fast early phase and a slow late phase.Two forms of Ca leak have been studied, Ca‐sensitising (induced by caffeine) and non‐sensitising (induced by ryanodine) and both induce biphasic decay of the Ca transient.Only Ca‐sensitising leak can be reversed by traditional RyR inhibitors such as tetracaine.Ca leak can also induce Ca waves. At low levels of leak, waves occur. As leak is increased, first biphasic decay and then slowed monophasic decay is seen. The level of leak has major effects on the shape of the Ca transient. Abstract In heart failure, a reduction in Ca transient amplitude and contractile dysfunction can by caused by Ca leak through the sarcoplasmic reticulum (SR) Ca channel (ryanodine receptor, RyR) and/or decreased activity of the SR Ca ATPase (SERCA). We have characterised the effects of two forms of Ca leak (Ca‐sensitising and non‐sensitising) on calcium cycling and compared with those of SERCA inhibition. We measured [Ca2+]i with fluo‐3 in voltage‐clamped rat ventricular myocytes. Increasing SR leak with either caffeine (to sensitise the RyR to Ca activation) or ryanodine (non‐sensitising) had similar effects to SERCA inhibition: decreased systolic [Ca2+]i, increased diastolic [Ca2+]i and slowed decay. However, in the presence of isoproterenol, leak produced a biphasic decay of the Ca transient in the majority of cells while SERCA inhibition produced monophasic decay. Tetracaine reversed the effects of caffeine but not of ryanodine. When caffeine (1 mmol l−1) was added to a cell which displayed Ca waves, the wave frequency initially increased before waves disappeared and biphasic decay developed. Eventually (at higher caffeine concentrations), the

  2. Ischemic damage in hippocampal CA1 is dependent on glutamate release and intact innervation from CA3

    DEFF Research Database (Denmark)

    Benveniste, H; Jørgensen, M B; Sandberg, M;

    1989-01-01

    The removal of glutamatergic afferents to CA1 by destruction of the CA3 region is known to protect CA1 pyramidal cells against 10 min of transient global ischemia. To investigate further the pathogenetic significance of glutamate, we measured the release of glutamate in intact and CA3-lesioned CA...... is dependent on glutamate release and intact innervation from CA3....

  3. Localized calcineurin confers Ca2+-dependent inactivation on neuronal L-type Ca2+ channels.

    Science.gov (United States)

    Oliveria, Seth F; Dittmer, Philip J; Youn, Dong-ho; Dell'Acqua, Mark L; Sather, William A

    2012-10-31

    Excitation-driven entry of Ca(2+) through L-type voltage-gated Ca(2+) channels controls gene expression in neurons and a variety of fundamental activities in other kinds of excitable cells. The probability of opening of Ca(V)1.2 L-type channels is subject to pronounced enhancement by cAMP-dependent protein kinase (PKA), which is scaffolded to Ca(V)1.2 channels by A-kinase anchoring proteins (AKAPs). Ca(V)1.2 channels also undergo negative autoregulation via Ca(2+)-dependent inactivation (CDI), which strongly limits Ca(2+) entry. An abundance of evidence indicates that CDI relies upon binding of Ca(2+)/calmodulin (CaM) to an isoleucine-glutamine motif in the carboxy tail of Ca(V)1.2 L-type channels, a molecular mechanism seemingly unrelated to phosphorylation-mediated channel enhancement. But our work reveals, in cultured hippocampal neurons and a heterologous expression system, that the Ca(2+)/CaM-activated phosphatase calcineurin (CaN) is scaffolded to Ca(V)1.2 channels by the neuronal anchoring protein AKAP79/150, and that overexpression of an AKAP79/150 mutant incapable of binding CaN (ΔPIX; CaN-binding PXIXIT motif deleted) impedes CDI. Interventions that suppress CaN activity-mutation in its catalytic site, antagonism with cyclosporine A or FK506, or intracellular perfusion with a peptide mimicking the sequence of the phosphatase's autoinhibitory domain-interfere with normal CDI. In cultured hippocampal neurons from a ΔPIX knock-in mouse, CDI is absent. Results of experiments with the adenylyl cyclase stimulator forskolin and with the PKA inhibitor PKI suggest that Ca(2+)/CaM-activated CaN promotes CDI by reversing channel enhancement effectuated by kinases such as PKA. Hence, our investigation of AKAP79/150-anchored CaN reconciles the CaM-based model of CDI with an earlier, seemingly contradictory model based on dephosphorylation signaling.

  4. Isolation and characterization of higher metallofullerenes Ca@C92 and Ca@C94

    Indian Academy of Sciences (India)

    Yuliang Che; Hua Yang; Hongxiao Jin; Chunxin Lu; Ziyang Liu

    2009-05-01

    We report for the first time isolation of Ca@C92 and Ca@C94 by multi-stage highperformance liquid chromatography technique without recycling equipment. It is notable that higher metallofullerenes containing alkaline earth metal ions could be isolated although their relative yields are extremely low. Ca@C92 and Ca@C94 are also confirmed by LD-TOF mass spectrometry and characterrized by UV-Vis-NIR absorption measurements.

  5. Ca(V)1 and Ca(V)2 channels engage distinct modes of Ca(2+) signaling to control CREB-dependent gene expression.

    Science.gov (United States)

    Wheeler, Damian G; Groth, Rachel D; Ma, Huan; Barrett, Curtis F; Owen, Scott F; Safa, Parsa; Tsien, Richard W

    2012-05-25

    Activity-dependent gene expression triggered by Ca(2+) entry into neurons is critical for learning and memory, but whether specific sources of Ca(2+) act distinctly or merely supply Ca(2+) to a common pool remains uncertain. Here, we report that both signaling modes coexist and pertain to Ca(V)1 and Ca(V)2 channels, respectively, coupling membrane depolarization to CREB phosphorylation and gene expression. Ca(V)1 channels are advantaged in their voltage-dependent gating and use nanodomain Ca(2+) to drive local CaMKII aggregation and trigger communication with the nucleus. In contrast, Ca(V)2 channels must elevate [Ca(2+)](i) microns away and promote CaMKII aggregation at Ca(V)1 channels. Consequently, Ca(V)2 channels are ~10-fold less effective in signaling to the nucleus than are Ca(V)1 channels for the same bulk [Ca(2+)](i) increase. Furthermore, Ca(V)2-mediated Ca(2+) rises are preferentially curbed by uptake into the endoplasmic reticulum and mitochondria. This source-biased buffering limits the spatial spread of Ca(2+), further attenuating Ca(V)2-mediated gene expression.

  6. Ca(2+) signalling in the Golgi apparatus.

    Science.gov (United States)

    Pizzo, Paola; Lissandron, Valentina; Capitanio, Paola; Pozzan, Tullio

    2011-08-01

    The Golgi apparatus plays a central role in lipid and protein post-translational modification and sorting. Morphologically the organelle is heterogeneous and it is possible to distinguish stacks of flat cysternae (cis- and medial Golgi), tubular-reticular networks and vesicles (trans-Golgi). These morphological differences parallel a distinct functionality with a selective distribution and complementary roles of the enzymes found in the different compartments. The Golgi apparatus has been also shown to be involved in Ca(2+) signalling: it is indeed endowed with Ca(2+) pumps, Ca(2+) release channels and Ca(2+) binding proteins and is thought to participate in determining the spatio-temporal complexity of the Ca(2+) signal within the cell, though this role is still poorly understood. Recently, it has been demonstrated that the organelle is heterogeneous in terms of Ca(2+) handling and selective reduction of Ca(2+) concentration, both in vitro and in a genetic human disease, within one of its sub-compartment results in alterations of protein trafficking within the secretory pathway and of the entire Golgi morphology. In this paper we review the available information on the Ca(2+) toolkit within the Golgi, its heterogeneous distribution in the organelle sub-compartments and discuss the implications of these characteristics for the physiopathology of the Golgi apparatus.

  7. LATS refining ladle slag modifying with CaO-CaF2

    Institute of Scientific and Technical Information of China (English)

    Hongming Wang; Guirong Li; Zhongming Ren; Bo Li; Xuejun Zhang; Guomin Shi

    2007-01-01

    To reduce the slag sticking onto the snorkel of the ladle during the ladle alloying treatment station (LATS) process, CaO-CaF2 (the mass ratio of CaO/CaF2 is 1:1) was employed as the modifier of the LATS refining ladle slag. The effect of CaO-CaF2 on the melting point, viscosity, and desulfurizing capability of the ladle slag was investigated. The melting point of the unmodified ladle slag is 1439°C. When adding 20wt% CaO-CaF2, the melting point is decreased to 1327°C. At 1500°C, the viscosity of the unmodified ladle slag is 6.5 Pa·s, which can be decreased lower than 2 Pa·s by adding more than 10wt% CaO-CaF2. The experimental results of desulfurization of the melts show that the desulfurizing power of the ladle slag can be enhanced by adding CaO-CaF2.

  8. By Regulating Mitochondrial Ca2+-Uptake UCP2 Modulates Intracellular Ca2+.

    Directory of Open Access Journals (Sweden)

    Lukas Jaroslaw Motloch

    Full Text Available The possible role of UCP2 in modulating mitochondrial Ca2+-uptake (mCa2+-uptake via the mitochondrial calcium uniporter (MCU is highly controversial.Thus, we analyzed mCa2+-uptake in isolated cardiac mitochondria, MCU single-channel activity in cardiac mitoplasts, dual Ca2+-transients from mitochondrial ((Ca2+m and intracellular compartment ((Ca2+c in the whole-cell configuration in cardiomyocytes of wild-type (WT and UCP2-/- mice.Isolated mitochondria showed a Ru360 sensitive mCa2+-uptake, which was significantly decreased in UCP2-/- (229.4±30.8 FU vs. 146.3±23.4 FU, P0.05 and transsarcolemmal Ca2+-influx was inhibited suggesting a possible compensatory mechanism. Additionally, we observed an inhibitory effect of ATP on mCa2+-uptake in WT mitoplasts and (Ca2+m of cardiomyocytes leading to an increase of (Ca2+c while no ATP dependent effect was observed in UCP2-/-.Our results indicate regulatory effects of UCP2 on mCa2+-uptake. Furthermore, we propose, that previously described inhibitory effects on MCU by ATP may be mediated via UCP2 resulting in changes of excitation contraction coupling.

  9. Ca-Dependent Folding of Human Calumenin

    Science.gov (United States)

    Mazzorana, Marco; Hussain, Rohanah; Sorensen, Thomas

    2016-01-01

    Human calumenin (hCALU) is a six EF-hand protein belonging to the CREC family. As other members of the family, it is localized in the secretory pathway and regulates the activity of SERCA2a and of the ryanodine receptor in the endoplasmic reticulum (ER). We have studied the effects of Ca2+ binding to the protein and found it to attain a more compact structure upon ion binding. Circular Dichroism (CD) measurements suggest a major rearrangement of the protein secondary structure, which reversibly switches from disordered at low Ca2+ concentrations to predominantly alpha-helical when Ca2+ is added. SAXS experiments confirm the transition from an unfolded to a compact structure, which matches the structural prediction of a trilobal fold. Overall our experiments suggest that calumenin is a Ca2+ sensor, which folds into a compact structure, capable of interacting with its molecular partners, when Ca2+ concentration within the ER reaches the millimolar range. PMID:26991433

  10. Levels of CEA, CA153, CA199, CA724 and AFP in nipple discharge of breast cancer patients.

    Science.gov (United States)

    Zhao, Song; Mei, Yu; Wang, Yongmei; Zhu, Jiang; Zheng, Guixi; Ma, Rong

    2015-01-01

    The distinction between breast cancer and benign breast diseases with nipple discharge remains an important diagnostic challenge. The purpose of this study was to predict the potential usefulness of tumor markers in nipple discharge and to investigate the relationship of tumor markers and clinical characteristics with breast cancer.One hundred and eleven patients with nipple discharge received breast surgery from November 2013 to December 2014 were included in the study. We evaluated levels of five tumor markers (CEA, CA153, CA199, CA724 and AFP) prior to treatment. Patients were divided into two groups according to postoperative pathological results: 30 cases in breast cancer group and 81 cases in benign group. The relationships of clinical characteristics with breast cancer were investigated by multivariate analysis with a logistic regression model.It showed significant differences in levels of nipple discharge CEA (P AFP (P = 0.834) among two groups. Logistic regression analysis demonstrated complaint, age, menopause, abnormal palpable mass, CEA and CA153 were associated with breast cancer. In summary, measurements of CA199, CA724 and AFP in nipple discharge are not of great clinical value. Detecting CEA and CA153 in nipple dischargecould potentially be used for the early detection of breast cancer with in high-risk populations.

  11. SR-targeted CaMKII inhibition improves SR Ca2+ handling, but accelerates cardiac remodeling in mice overexpressing CaMKIIδC

    OpenAIRE

    Huke, Sabine; DeSantiago, Jaime; Kaetzel, Marcia A.; Mishra, Shikha; Brown, Joan H.; Dedman, John R.; Bers, Donald M.

    2010-01-01

    Cardiac myocyte overexpression of CaMKIIδC leads to cardiac hypertrophy and heart failure (HF) possibly caused by altered myocyte Ca2+ handling. A central defect might be the marked CaMKII-induced increase in diastolic sarcoplasmic reticulum (SR) Ca2+ leak which decreases SR Ca2+ load and Ca2+ transient amplitude. We hypothesized that inhibition of CaMKII near the SR membrane would decrease the leak, improve Ca2+ handling and prevent the development of contractile dysfunction and HF. To test ...

  12. Results of measuring internal Ca absorption and Ca kinetics with /sup 47/Ca in patients suffering from chronically recurrent urolithiasis

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, L.; Esther, G.; Serfling, D.; Bast, R. (Rostock Univ. (German Democratic Republic). Radiologische Klinik)

    1983-07-01

    47 patients with chronically recurrent calcium lithiasis (with between 3 and over 100 stone episodes) and an average age of 43.2 years have been examined. The Ca absorption lay between 42.7% and 90.0% of the dose, the average was 59.3% with a standard deviation of +- 12.9. This is higher than in persons with healthy kidneys. The Ca absorption is significantly lower in patients with renal insufficiency. Studies on Ca kinetics revealed turnover rates and pool sizes within the normal range.

  13. Isospin effects in {sup 40,48}Ca+{sup 40,48}Ca collisions

    Energy Technology Data Exchange (ETDEWEB)

    Henzl, V., E-mail: henzl@mit.ed [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States); Henzlova, D.; Kilburn, M. [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States); Verde, G. [INFN, Sezione di Catania. 64 Via S. Sofia, I-95123, Catania (Italy); Brown, D. [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States); Chbihi, A. [GANIL, CEA et IN2P3-CNRS, B.P. 5027, F-14076 Caen Cedex (France); Coupland, D. [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States); Elson, J. [Departments of Chemistry and Physics, Washington University, St. Louis, MO 63130 (United States); Famiano, M. [Western Michigan University, 2229 Everett Tower, Kalamazoo, MI 49008-5252 (United States); Herlitzius, C. [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States); Hudan, S. [Indiana Univ. Cyclotron Facility, 2401 Milo B. Sampson Lane, Bloomington, IN 47405-4001 (United States); Lee, J.; Lukyanov, S.; Lynch, W.; Rogers, A.; Sanetullaev, A. [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States); Sobotka, L. [Departments of Chemistry and Physics, Washington University, St. Louis, MO 63130 (United States); Souza, R.T. de [Indiana Univ. Cyclotron Facility, 2401 Milo B. Sampson Lane, Bloomington, IN 47405-4001 (United States); Sun, Z.Y.; Tsang, B. [MSU-NSCL, 1 Cyclotron, East Lansing MI, 48824 (United States)

    2010-03-01

    The isospin dependence of two proton correlations is studied in {sup 40}Ca+{sup 40}Ca and {sup 48}Ca+{sup 48}Ca collisions at E/A=80MeV. Measurements were performed with the HiRA detector array complemented by the 4pi Ball at NSCL. We observe a strong isospin dependence of the pp-correlation functions; however the emitting source radius extracted using the imaging technique yields no sensitivity to the isospin of the reaction system. We interpret this result as a consequence of smaller fraction of fast proton emission in the neutron rich {sup 48}Ca system.

  14. Toosendanin increases free-Ca2+ concentration in NG108-15 cells via L-type Ca2+ channels

    Institute of Scientific and Technical Information of China (English)

    Tong-hui XU; Jun DING; Yu-liang SHI

    2004-01-01

    AIM: To examine if toosendanin (TSN) affects intracellular free-Ca2+ concentration ([Ca2+]i) in neuroblastomaxglioma hybrid cells (NG108-15 cells). METHODS: The [Ca2+]i was determined by laser-scanning confocal microscopic imaging technique in which Fluo-3 was used as Ca2+ indicator. RESULTS: TSN induced an increase in resting [Ca2+]i and in high K+-evoked Ca2+ transient in differentiated NG108-15 cells. The TSN-induced increase in [Ca2+]i was dose-dependent and disappeared in CdCl2-, nifedipine-containing or Ca2+-free solution, and appeared after washing out the Ca2+ channel blockers or adding Ca2+. CONCLUSION: TSN increased [Ca2+]i in differentiated NG108-15 cells. The [Ca2+]i enhancement was due to the influx of extracellular Ca2+ and related to L-type Ca2+ channels.

  15. Ca2+ sparks and Ca2+ glows in superior cervical ganglion neurons

    Institute of Scientific and Technical Information of China (English)

    Li-jun YAO; Cai-hong WU; Jie LIU; Zhuan ZHOU; He-ping CHENG; Gang WANG; Kun-fu OU-YANG; Chao-liang WEI; Xian-hua WANG; Shi-rong WANG; Wei YAO; Hong-ping HUANG; Jian-hong LUO

    2006-01-01

    Aim: Ca2+ release from the endoplasmic reticulum (ER) is an integral component of neuronal Ca2+ signaling. The present study is to investigate properties of local Ca2+ release events in superior cervical ganglion (SCO) neurons. Methods: Primary cultured SCO neurons were prepared from neonatal rats (P3-P7). Low concentration of caffeine was used to induce Ca2+ release from the ER Ca2+ store, and intracellular Ca2+ was recorded by high-resolution line scan confocal imaging and the Ca2+ indicator Fluo-4. Results: Two populations of local Ca2+ release events with distinct temporal characteristics were evoked by 1.5 mmol/L caffeine near the surface membrane in the soma and the neurites of SCG neurons. Brief events similar to classic Ca2+ sparks lasted a few hundreds of milliseconds, whereas long-lasting events displayed duration up to tens of seconds. Typical somatic and neurite sparks were of 0.3- and 0.52-fold increase in local Fluo-4 fluorescence, respectively. Typical Ca2+ glows were brighter (△F/F0 approximately 0.6), but were highly confined in space. The half maximum of full duration of neurite sparks was much longer than those in the soma (685 vs 381 ms). Conclusion: Co-existence of Ca2+ sparks and Ca2+ glows in SCG neurons indicates distinctive local regulation of Ca2+ release kinetics. The local Ca2+ signals of variable, site-specific temporal length may bear important implications in encoding a "memory" of the trigger signal.

  16. Serum level of TSGF,CA242 and CA19-9 in pancreatic cancer

    Institute of Scientific and Technical Information of China (English)

    Jing-Ting Jiang; Chang-Ping Wu; Hai-Feng Deng; Ming-Yang Lu; Jun Wu; Hong-Yu Zhang; Wen-Hui Sun; Mei Ji

    2004-01-01

    AIM: To establish a method to detect the expression of the tumor specific growth factor TSGF, CA242 and CA19-9 in serum and evaluate their value in diagnosis of pancreatic cancer.METHODS: ELISA and Biochemical colorimetric assay were used to detect the serum content of TSGF, CA242 and CA19-9 in 200 normal cases, 52 pancreatitis patients and 96 pancreatic cancer patients.RESULTS: The positive likelihood ratios of TSGF, CA242and CA19-9 were 5.4, 12.6 and 6.3, respectively, and their negative likelihood ratios were 0.10, 0.19 and 0.17,respectively. With single tumor marker diagnosed pancreatic cancer, the highest sensitivity and specificity of TSGF were 91.6% and 93.5%. In combined test with 3 markers, when all of them were positive, the sensitivity changed to 77.0%and the specificity and the positive predictive value were 100%. The levels of TSGF and CA242 were significantly higher in the patients with pancreatic cancer of head than those in the patients with pancreatic cancer of body, tail and whole pancreas, but the expression of CA19-9 had no correlation with the positions of the pancreatic cancer. The sensitivity of TSGF, CA242 and CA19-9 was increased with the progress in stages of pancreatic cancer. In stage I, the sensitivity of TSGF was markedly higher than CA242 and CA19-9.CONCLUSION: The combined use of TSGF, CA242 and CA19-9 expressions can elevate the specificity for pancreatic cancer diagnosis. And it shows that it plays an important role to differentiate positions and tissue typing. It is a forepart diagnosis for the pancreatic cancer by combination checking.There is very important correlation between the three markers and the pancreatic cancer.

  17. Behavior of CaO and Calcium in pure Magnesium

    Institute of Scientific and Technical Information of China (English)

    HA Seong-Ho; LEE Jin-Kyu; JO Hyung-Ho; JUNG Seung-Boo; KIM Shae K.

    2006-01-01

    Mg alloys exhibit a number of good properties such as low density, good castability and high specific strength.However, molten Mg and Mg alloys are ignited without the melt protective gases during melting and casting process due to their high reactivity.The purpose of this study is to investigate effects of Ca and CaO on pure Mg through microstructure observation, ignition test and phase analysis.With increasing Ca and CaO contents, the ignition resistance of Ca or CaO added pure Mg is increased and the grains are refined.As results of XRD and EDS, CaO is reduced to Ca in CaO added pure Mg.Mg2Ca phase is formed even in 0.1 wt.%CaO added pure Mg by reduction mechanism, while Mg2Ca phase is formed over 1.35 wt.% Ca added pure Mg.

  18. Study on Roasting Decomposition of Mixed Rare Earth Concentrate in CaO-NaCl-CaCl2

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The decomposed process of bastnaesite, monazite and mixed rare earth concentrate in CaO-CaCl-CaCl2 was studied by means of TG-DTA method. The relationship among decomposition ratio, roasting temperature, and CaO-NaCl addition was studied by the quadratic regression orthogonal analysis, and then the regression equation was obtained. Through analysis, the optimum process conditions of mixed rare earth concentrate decomposed by CaO-CaCl-CaCl2 were obtained as follows: roasting temperature: 700 ℃, CaO addition: 15%, NaCl-CaCl2 addition: 10%, roasting time: 60 min, the decomposition ratio: 91.3%.

  19. Regulated release of Ca2+ from respiring mitochondria by Ca2+/2H+ antiport.

    Science.gov (United States)

    Fiskum, G; Lehninger, A L

    1979-07-25

    Simultaneous measurements of oxygen consumption and transmembrane transport of Ca2+, H+, and phosphate show that the efflux of Ca2+ from respiring tightly coupled rat liver mitochondria takes place by an electroneutral Ca2+/2H+ antiport process that is ruthenium red-insensitive and that is regulated by the oxidation-reduction state of the mitochondrial pyridine nucleotides. When mitochondrial pyridine nucleotides are kept in a reduced steady state, the efflux of Ca2+ is inhibited; when they are in an oxidized state, Ca2+ efflux is activated. These processes were demonstrated by allowing phosphate-depleted mitochondria respiring on succinate in the presence of rotenone to take up Ca2+ from the medium. Upon subsequent addition of ruthenium red to block Ca2+ transport via the electrophoretic influx pathway, and acetoacetate, to bring mitochondrial pyridine nucleotides into the oxidized state, Ca2+ efflux and H+ influx ensued. The observed H+ influx/Ca2+ efflux ratio was close to the value 2.0 predicted for the operation of an electrically neutral Ca2+/2H+ antiport process.

  20. Prognostic significance of preoperative serum CA125, CA19-9 and CEA in gastric carcinoma

    Science.gov (United States)

    Wang, Wei; Chen, Xiao-Long; Zhao, Shen-Yu; Xu, Yu-Hui; Zhang, Wei-Han; Liu, Kai; Chen, Xin-Zu; Yang, Kun; Zhang, Bo; Chen, Zhi-Xin; Chen, Jia-Ping; Zhou, Zong-Guang; Hu, Jian-Kun

    2016-01-01

    The prognostic significance of preoperative serum CA125, CA19-9 and CEA in gastric carcinoma (GC) has been widely reported and is still under debate. Here, we evaluated the prognostic significance of preoperative serum CA125, CA19-9 and CEA in patients with GC. 1692 patients with GC who underwent gastrectomy were divided into the training (from January 2005 to December 2011, n = 1024) and the validation (from January 2012 to December 2013, n = 668) cohorts. Positive groups of CA125 (> 13.72 U/ml), CA19-9 (> 23.36 U/ml) and CEA (> 4.28 ng/ml) were significantly associated with more advanced clinicopathological traits and worse outcomes than that of negative groups (all P < 0.01). In Cox regression analysis, tumor size (P < 0.001, P = 0.005), pTNM stage (P < 0.001, P < 0.001) and CA125 (P = 0.026, P = 0.005) were independent prognostic factors both in two cohorts. Nomograms of these two cohorts based on the number of positive serum tumor markers (NPTM) were more accurate in prognostic prediction than TNM stage alone. Our findings suggested that elevated preoperative serum CA125, CA19-9 and CEA were associated with more advanced clinicopathological traits and less favorable outcomes. In addition, CA125 as an independent prognostic factor should be further investigated. Nomogram based on NPTM could accurately predict the prognosis of GC patients. PMID:27097114

  1. Aging and CaMKII Alter Intracellular Ca2+ Transients and Heart Rhythm in Drosophila melanogaster

    Science.gov (United States)

    Santalla, Manuela; Valverde, Carlos A.; Harnichar, Ezequiel; Lacunza, Ezequiel; Aguilar-Fuentes, Javier; Mattiazzi, Alicia; Ferrero, Paola

    2014-01-01

    Aging is associated to disrupted contractility and rhythmicity, among other cardiovascular alterations. Drosophila melanogaster shows a pattern of aging similar to human beings and recapitulates the arrhythmogenic conditions found in the human heart. Moreover, the kinase CaMKII has been characterized as an important regulator of heart function and an arrhythmogenic molecule that participate in Ca2+ handling. Using a genetically engineered expressed Ca2+ indicator, we report changes in cardiac Ca2+ handling at two different ages. Aging prolonged relaxation, reduced spontaneous heart rate (HR) and increased the occurrence of arrhythmias, ectopic beats and asystoles. Alignment between Drosophila melanogaster and human CaMKII showed a high degree of conservation and indicates that relevant phosphorylation sites in humans are also present in the fruit fly. Inhibition of CaMKII by KN-93 (CaMKII-specific inhibitor), reduced HR without significant changes in other parameters. By contrast, overexpression of CaMKII increased HR and reduced arrhythmias. Moreover, it increased fluorescence amplitude, maximal rate of rise of fluorescence and reduced time to peak fluorescence. These results suggest that CaMKII in Drosophila melanogaster acts directly on heart function and that increasing CaMKII expression levels could be beneficial to improve contractility. PMID:25003749

  2. EnviroAtlas - Fresno, CA - Block Groups

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset is the base layer for the Fresno, CA EnviroAtlas area. The block groups are from the US Census Bureau and are included/excluded based on...

  3. Role of Ca++ in Shoot Gravitropism. [avena

    Science.gov (United States)

    Rayle, D. L.

    1985-01-01

    A cornerstone in the argument that Ca(2+) levels may regulate growth is the finding the EGTA promotes straight growth. The usual explanation for these results is that Ca(2+) chelation from cell walls results in wall loosening and thus accelerated straight growth. The ability of frozen-thawed Avena coleoptile tissue (subjected to 15g tension) to extend in response to EGTA and Quin II was examined. The EGTA when applied in weakly buffered (i.e., 0.1mM) neutral solutions initiates rapid extension. When the buffer strength is increased, similar concentrations of EGTA produce no growth response. This implies when EGTA liberated protons are released upon Ca(2+) chelation they can either initiate acid growth (low buffer conditions) or if consumed (high buffer conditions) have no effect. Thus Ca(2+) chelation in itself apparently does not result in straight growth.

  4. Distribution of CA 125 in placental tissues.

    Science.gov (United States)

    Fuith, L C; Müller-Holzner, E; Marth, C; Perkmann, E; Zeimet, A; Daxenbichler, G

    1989-01-01

    The presence of the tumor marker CA 125 was studied in different compartments of the human placenta. Levels of CA 125 in the cytosol of chorionic villi ranged from 27-17100 U/g (median 560 U/g). In the placental amnion and chorion concentrations ranged from 175-29000 U/g, median 1060 U/g and were not statistically different. In the umbilical cord values were significantly lower (range 44-7600 U/g; median 180 U/g). Maternal serum probes were above the upper limit of normal in all cases (range 48-500 U/ml; median 131 U/ml). Immunohistochemistry detected CA 125 exclusively within the amniotic cells of the placenta and the umbilical cord. This might be because CA 125 fixes more to insoluble structures in the amnion or because of contamination of chorionic villi with the underlying decidua.

  5. CaMath user`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Ben-chin; Daly, B.

    1994-07-13

    CaMath is an external Mathematica package which can be loaded into Mathematica by a user. CaMath consists of a special set of channel access functions which provides the Mathematica users with easy and flexible access of channel information across the IOC networks. It also provides a complete set of process variable event monitoring functions. The available functions for CaMath, their functionality, and their syntax are described herein. This document also gives examples how a Mathematica user can interface to channel access devices. It is assumed that the user is already familiar with using Mathematica. Few examples of Mathematica module of using CaMath functions are also given in this document.

  6. CA Investment Casting Process of Complex Castings

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    CA (Computer aided) investment casting technique used in superalloy castings of aerospace engine parts was presented. CA investment casting integrated computer application, RP (Rapid Prototyping) process, solidification simulation and investment casting process. It broke the bottle neck of making metal die. Solid model of complex parts were produced by UGII or other software, then translated into STL(Stereolithography) file, after RP process of SLS(Selective Laser Sintering), wax pattern used in investment ...

  7. YouthCaN 2001 / Sirje Janikson

    Index Scriptorium Estoniae

    Janikson, Sirje

    2001-01-01

    Aprillis 2001 toimus keskkonnateemaline õpilaskonverents YouthCaN 2001 Ameerika Loodusajaloo Muuseumis New Yorkìs. 35 seminarist ühe viis läbi Tartu Noorte Loodusmaja geoloogia ja keskkonnaringi esindus, tutvustati loodusmaja keskkonnaprojekte ja räägiti keskkonnaalaste veebilehtede koostamise kogemustest. YouthCaN (Youth Communicating and Networking) on rahvusvaheline noorte organisatsioon, mis vahendab kogemusi ja uusi ideid elukeskkonnast huvitatud noorte hulgas

  8. PIK3CA in colorectal cancer

    Directory of Open Access Journals (Sweden)

    Gieri eCathomas

    2014-03-01

    Full Text Available PIK3CA, the catalytic subunit of PI3K, is mutated in many different tumours, including colorectal cancer. Mutations of PIK3CA have been reported in 10 – 20% of colorectal cancer, about 80% of mutations found in two hot spots in exon 9 and exon 20. In RAS wild-type colorectal cancers, PIK3CA mutations have been associated with a worse clinical outcome and with a negative prediction of a response to targeted therapy by anti-EGFR monoclonal antibodies. However, these findings have not been confirmed in all studies and subsequent more detailed analysis has revealed that these effects may be restricted to mutations in Exon 20. Finally, mutations in PIK3CA may be the long sought biomarker for successful adjuvant therapy with aspirin in patients with colorectal cancer. Therefore, PIK3CA mutations appear to be a promising predictive biomarker; however, further data are needed to conclusively define the impact of somatic mutations in the PIK3CA gene for the management of patients with colorectal cancer.

  9. Mitochondrial Ca2+ uptake in skeletal muscle health and disease

    CERN Document Server

    Zhou, Jingsong; Yi, Jianxun

    2016-01-01

    Muscle uses Ca2+ as a messenger to control contraction and relies on ATP to maintain the intracellular Ca2+ homeostasis. Mitochondria are the major sub-cellular organelle of ATP production. With a negative inner membrane potential, mitochondria take up Ca2+ from their surroundings, a process called mitochondrial Ca2+ uptake. Under physiological conditions, Ca2+ uptake into mitochondria promotes ATP production. Excessive uptake causes mitochondrial Ca2+ overload, which activates downstream adverse responses leading to cell dysfunction. Moreover, mitochondrial Ca2+ uptake could shape spatio-temporal patterns of intracellular Ca2+ signaling. Malfunction of mitochondrial Ca2+ uptake is implicated in muscle degeneration. Unlike non-excitable cells, mitochondria in muscle cells experience dramatic changes of intracellular Ca2+ levels. Besides the sudden elevation of Ca2+ level induced by action potentials, Ca2+ transients in muscle cells can be as short as a few milliseconds during a single twitch or as long as min...

  10. X-Ray Data on Extraterrestrial CA Dialuminate (CaAl4O7)

    Science.gov (United States)

    Weber, D.; Ross, C. R., II; Bischoff, A.

    1993-07-01

    After the first discovery of Ca-dialuminate (CaAl4O7) in Allende [1], in recent years this phase has been found in several carbonaceous chondrites. Ca- dialuminate is a major phase in Ca,Al-rich inclusions from ALH85085 (e.g., [2]) and a dominating phase in CAIs from Acfer 182 ([3,4]). X-ray data on Ca-dialuminate are known from synthetic (e.g., [5-8]; cell constants) and terrestrial CaAl4O7 ([9]; only d-spacings), but are not available from extraterrestrial Ca-dialuminate. We report here the results of the first X-ray study of extraterrestrial Ca- dialuminate. The data (Table 1) were obtained by microdiffraction using a Rigaku PSPC microdiffractometer at the Bayerisches Geoinstitut. Ni-filtered Cr radiation was used with a direct beam diameter of about 50 micrometers. This powder diffraction method allows in situ measurement of polycrystalline Ca- dialuminate in a thin section. The CaAl4O7-rich inclusion 022/9 described in [4], consisting of a ~200-micrometer-sized core of Ca-dialuminate surrounded by layers of melilite and Ca-pyroxene, was chosen for analysis. The polycrystalline core contains only a small number of tiny inclusions (especially perovskite) and is therefore an excellent candidate for an X-ray study. For determination of the d-spacings of Ca-dialuminate an external standard (Ag6Ge10P12) was used for detector calibration. A large number of reflections could be indexed based upon comparison with the X-ray pattern of synthetic CaAl4O7 available in the JCPDS compilation [7]. The comparison was simplified because of the high purity of CaAl4O7 in inclusion 022/9 [4], and suggests the same structure for synthetic and extraterrestrial Ca-dialuminate. For determination of lattice parameters (cell constants, cell volume) refinement calculations were made based on 14 reflections (Table 1). The data for extraterrestrial CaAl4O7 shown in Table 1 indicate a close similarity to those obtained for synthetic CaAl4O7. The cell constants a, b, and therefore the cell

  11. Sarcolemmal Ca(2+)-entry through L-type Ca(2+) channels controls the profile of Ca(2+)-activated Cl(-) current in canine ventricular myocytes.

    Science.gov (United States)

    Horváth, Balázs; Váczi, Krisztina; Hegyi, Bence; Gönczi, Mónika; Dienes, Beatrix; Kistamás, Kornél; Bányász, Tamás; Magyar, János; Baczkó, István; Varró, András; Seprényi, György; Csernoch, László; Nánási, Péter P; Szentandrássy, Norbert

    2016-08-01

    Ca(2+)-activated Cl(-) current (ICl(Ca)) mediated by TMEM16A and/or Bestrophin-3 may contribute to cardiac arrhythmias. The true profile of ICl(Ca) during an actual ventricular action potential (AP), however, is poorly understood. We aimed to study the profile of ICl(Ca) systematically under physiological conditions (normal Ca(2+) cycling and AP voltage-clamp) as well as in conditions designed to change [Ca(2+)]i. The expression of TMEM16A and/or Bestrophin-3 in canine and human left ventricular myocytes was examined. The possible spatial distribution of these proteins and their co-localization with Cav1.2 was also studied. The profile of ICl(Ca), identified as a 9-anthracene carboxylic acid-sensitive current under AP voltage-clamp conditions, contained an early fast outward and a late inward component, overlapping early and terminal repolarizations, respectively. Both components were moderately reduced by ryanodine, while fully abolished by BAPTA, but not EGTA. [Ca(2+)]i was monitored using Fura-2-AM. Setting [Ca(2+)]i to the systolic level measured in the bulk cytoplasm (1.1μM) decreased ICl(Ca), while application of Bay K8644, isoproterenol, and faster stimulation rates increased the amplitude of ICl(Ca). Ca(2+)-entry through L-type Ca(2+) channels was essential for activation of ICl(Ca). TMEM16A and Bestrophin-3 showed strong co-localization with one another and also with Cav1.2 channels, when assessed using immunolabeling and confocal microscopy in both canine myocytes and human ventricular myocardium. Activation of ICl(Ca) in canine ventricular cells requires Ca(2+)-entry through neighboring L-type Ca(2+) channels and is only augmented by SR Ca(2+)-release. Substantial activation of ICl(Ca) requires high Ca(2+) concentration in the dyadic clefts which can be effectively buffered by BAPTA, but not EGTA.

  12. Endothelin-1 induces intracellular [Ca2+] increase via Ca2+ influx through the L-type Ca2+ channel, Ca2+-induced Ca2+ release and a pathway involving ETA receptors, PKC, PKA and AT1 receptors in cardiomyocytes

    Institute of Scientific and Technical Information of China (English)

    ZENG QingHua; LI XingTing; ZHONG GuoGan; ZHANG WenJie; SUN ChengWen

    2009-01-01

    Using fura-2-acetoxymethyl eater (AM) fluorescence imaging and patch clamp techniques, we found that endothelin-1 (ET-1) significantly elevated the intracellular calcium level ([Ca2+]1) in a dose-dependent manner and activated the L-type Ca2+ channel in cardiomyocytes isolated from rats.The effect of ET-1 on [Ca2+]1 elevation was abolished in the presence of the ETA receptor blocker BQ123,but was not affected by the ETa receptor blocker BQ788. ET-1-induced an increase in [Ca2+]1, which was inhibited 46.7% by pretreatment with a high concentration of ryanodine (10 μmol/L), a blocker of the ryanodine receptor. The ET-1-induced [Ca2+]i increase was also inhibited by the inhibltors of protein kinase A (PKA), protein kinase C (PKC) and angiotensin type 1 receptor (AT1 receptor). We found that ET-1 induced an enhancement of the amplitude of the whole cell L-type Ca2+ channel current and an Increase of open-state probability (NPo) of an L-type single Ca2+ channel. BQ123 completely blocked the ET-1-induced increase in calcium channel open-state probability. In this study we demonstrated that ET-1 regulates calcium overload through a series of mechanisms that include L-type Ca2+ channel activation and Ca2+-induced Ca2+ release (CICR). ETa receptors, PKC, PKA and AT1 receptors may also contribute to this pathway.

  13. Endothelin-1 induces intracellular [Ca2+] increase via Ca2+ influx through the L-type Ca2+ channel, Ca2+-induced Ca2+ release and a pathway involving ETA receptors, PKC, PKA and AT1 receptors in cardiomyocytes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Using fura-2-acetoxymethyl ester (AM) fluorescence imaging and patch clamp techniques, we found that endothelin-1 (ET-1) significantly elevated the intracellular calcium level ([Ca2+]i) in a dose-dependent manner and activated the L-type Ca2+ channel in cardiomyocytes isolated from rats. The effect of ET-1 on [Ca2+]i elevation was abolished in the presence of the ETA receptor blocker BQ123, but was not affected by the ETB receptor blocker BQ788. ET-1-induced an increase in [Ca2+]i, which was inhibited 46.7% by pretreatment with a high concentration of ryanodine (10 μmol/L), a blocker of the ryanodine receptor. The ET-1-induced [Ca2+]i increase was also inhibited by the inhibitors of protein kinase A (PKA), protein kinase C (PKC) and angiotensin type 1 receptor (AT1 receptor). We found that ET-1 induced an enhancement of the amplitude of the whole cell L-type Ca2+ channel current and an increase of open-state probability (NPo) of an L-type single Ca2+ channel. BQ123 completely blocked the ET-1-induced increase in calcium channel open-state probability. In this study we demonstrated that ET-1 regulates calcium overload through a series of mechanisms that include L-type Ca2+ channel activation and Ca2+-induced Ca2+ release (CICR). ETA receptors, PKC, PKA and AT1 receptors may also contribute to this pathway.

  14. Mitochondrial calcium uniporter MCU supports cytoplasmic Ca2+ oscillations, store-operated Ca2+ entry and Ca2+-dependent gene expression in response to receptor stimulation.

    Science.gov (United States)

    Samanta, Krishna; Douglas, Sophie; Parekh, Anant B

    2014-01-01

    Ca2+ flux into mitochondria is an important regulator of cytoplasmic Ca2+ signals, energy production and cell death pathways. Ca2+ uptake can occur through the recently discovered mitochondrial uniporter channel (MCU) but whether the MCU is involved in shaping Ca2+ signals and downstream responses to physiological levels of receptor stimulation is unknown. Here, we show that modest stimulation of leukotriene receptors with the pro-inflammatory signal LTC4 evokes a series of cytoplasmic Ca2+ oscillations that are rapidly and faithfully propagated into mitochondrial matrix. Knockdown of MCU or mitochondrial depolarisation, to reduce the driving force for Ca2+ entry into the matrix, prevents the mitochondrial Ca2+ rise and accelerates run down of the oscillations. The loss of cytoplasmic Ca2+ oscillations appeared to be a consequence of enhanced Ca2+-dependent inactivation of InsP3 receptors, which arose from the loss of mitochondrial Ca2+ buffering. Ca2+ dependent gene expression in response to leukotriene receptor activation was suppressed following knockdown of the MCU. In addition to buffering Ca2+ release, mitochondria also sequestrated Ca2+ entry through store-operated Ca2+ channels and this too was prevented following loss of MCU. MCU is therefore an important regulator of physiological pulses of cytoplasmic Ca2+.

  15. Mitochondrial calcium uniporter MCU supports cytoplasmic Ca2+ oscillations, store-operated Ca2+ entry and Ca2+-dependent gene expression in response to receptor stimulation.

    Directory of Open Access Journals (Sweden)

    Krishna Samanta

    Full Text Available Ca2+ flux into mitochondria is an important regulator of cytoplasmic Ca2+ signals, energy production and cell death pathways. Ca2+ uptake can occur through the recently discovered mitochondrial uniporter channel (MCU but whether the MCU is involved in shaping Ca2+ signals and downstream responses to physiological levels of receptor stimulation is unknown. Here, we show that modest stimulation of leukotriene receptors with the pro-inflammatory signal LTC4 evokes a series of cytoplasmic Ca2+ oscillations that are rapidly and faithfully propagated into mitochondrial matrix. Knockdown of MCU or mitochondrial depolarisation, to reduce the driving force for Ca2+ entry into the matrix, prevents the mitochondrial Ca2+ rise and accelerates run down of the oscillations. The loss of cytoplasmic Ca2+ oscillations appeared to be a consequence of enhanced Ca2+-dependent inactivation of InsP3 receptors, which arose from the loss of mitochondrial Ca2+ buffering. Ca2+ dependent gene expression in response to leukotriene receptor activation was suppressed following knockdown of the MCU. In addition to buffering Ca2+ release, mitochondria also sequestrated Ca2+ entry through store-operated Ca2+ channels and this too was prevented following loss of MCU. MCU is therefore an important regulator of physiological pulses of cytoplasmic Ca2+.

  16. Physical conditions in CaFe interstellar clouds

    OpenAIRE

    Gnacinski, P.; Krogulec, M.

    2007-01-01

    Interstellar clouds that exhibit strong Ca I and Fe I lines were called CaFe clouds. The ionisation equilibrium equations were used to model the column densities of Ca II, Ca I, K I, Na I, Fe I and Ti II in CaFe clouds. The chemical composition of CaFe clouds is that of the Solar System and no depletion of elements onto dust grains is seen. The CaFe clouds have high electron densities n=1 cm^-3 that leads to high column densities of neutral Ca and Fe.

  17. Heat and hyposmotic stimulation increase in [Ca2+]i by Ca2+ influx in rat synoviocytes

    Institute of Scientific and Technical Information of China (English)

    SUN WenWu; HU Fen; YANG WenXiu

    2008-01-01

    Rheumatoid arthritis (RA), which is marked by inflammatory synovitis, is a common, chronic autoimmune-disease, whose pathogenesis is complex and still unclear. In order to explore the effects of heat and hyposmotic stimuli on synoviocytes in rheumatoid arthritis, the changes of [Ca2+]i induced by heat, hyposmotic and 4α-PDD stimuli were observed in synoviocytes. [Ca2+]i elevation induced by heat ≥ 28℃, hyposmotic and 4α-PDD stimuli is found to be positively relative to increasing temperature, decreasing osmolality and rising concentration of 4α-PDD. Results show that there is reciprocity among these stimuli and desensitization, and that [Ca2+]i elevation depends on Ca2+ influx, but not necessarily links to Ca2+ release from intracellular stores and voltage-dependent Ca2+ channel in synoviocytes. The above characteristics of Ca2+ influx are similar to those of TRPV4. A probable mechanism has been suggested that heat and hyposmotic stimulation might increase the level of [Ca2+]i by activating the TRPV4-like channel and Ca2+ influx in the synoviocytes.

  18. Relationship Between Ca2+-CaM and Ethylene-Induced PG Activity in Tomato Fruit

    Institute of Scientific and Technical Information of China (English)

    GU Cai-qin; XI Yu-fang; GUAN Jun-feng; LI Guang-min

    2003-01-01

    Polygalacturonase (PG) was studied during ripening and senescence of postharvest tomatofruit at pink stage at low and normal temperature. The results showed that the PG activity increased, thendecreased during ripening and senescence of tomato. Low temperature inhibited but ethylene enhanced PGactivity. Ethylene also enhanced caimodulin content, which was dependent on Ca2+ concentration in cell.When EGTA(Ca2+ chelator), verapamil (Vp) and LaCl3 (Ca2+ channel blockers), trifluoperazine and chloro-promaize (two CaM antagonisms) were used to treat tomato fruit at green mature stage with ethylene, theycould reverse ethylene-induced increase in PG activity, but Vp, chloropromaize (CPZ), trifluoperazine(TFP) could not directly influence PG activity, which indirectly indicated that influx of Ca2+ from the ex-tracellular space including the cell wall via the Ca2+ channel localized in plasma membrane and CaM were re-quired for ethylene-induced PG activity increase and that ethylene signal transduction may be related to Ca2+- CaM messenger system.

  19. CaCl2-CaO熔盐中金属钙的电沉积行为研究

    Institute of Scientific and Technical Information of China (English)

    郭君康

    2014-01-01

    在900℃下,采用循环伏安法对CaCl2-CaO熔盐中金属钙的电沉积行为进行了研究.研究结果表明,在CaCl2熔盐中加入CaO后,熔盐中Ca2+的还原电位正移,且Ca2+的还原过程受扩散控制.

  20. CaMKII inhibition targeted to the sarcoplasmic reticulum inhibits frequency dependent acceleration of relaxation and Ca2+ current facilitation

    OpenAIRE

    Picht, Eckard; DeSantiago, Jaime; Huke, Sabine; Kaetzel, Marcia A.; Dedman, John R.; Bers, Donald M.

    2006-01-01

    Cardiac Ca2+/calmodulin-dependent protein kinase II (CaMKII) in heart has been implicated in Ca2+ current (ICa) facilitation, enhanced sarcoplasmic reticulum (SR) Ca2+ release and frequency dependent acceleration of relaxation (FDAR) via enhanced SR Ca2+ uptake. However, questions remain about how CaMKII may work in these three processes. Here we tested the role of CaM-KII in these processes using transgenic mice (SR-AIP) that express four concatenated repeats of the CaMKII inhibitory peptide...

  1. Diffusion of Ca and Mg in Calcite

    Energy Technology Data Exchange (ETDEWEB)

    Cygan, R.T.; Fisler, D.K.

    1999-02-10

    The self-diffusion of Ca and the tracer diffusion of Mg in calcite have been experimentally measured using isotopic tracers of {sup 25}Mg and {sup 44}Ca. Natural single crystals of calcite were coated with a thermally-sputtered oxide thin film and then annealed in a CO{sub 2} gas at one atmosphere total pressure and temperatures from 550 to 800 C. Diffusion coefficient values were derived from the depth profiles obtained by ion microprobe analysis. The resultant activation energies for Mg tracer diffusion and Ca self-diffusion are respectively: E{sub a}(Mg) = 284 {+-} 74 kJ/mol and E{sub a}(Ca) = 271 {+-} 80 kJ/mol. For the temperature ranges in these experiments, the diffusion of Mg is faster than Ca. The results are generally consistent in magnitude with divalent cation diffusion rates obtained in previous studies and provide a means of interpreting the thermal histories of carbonate minerals, the mechanism of dolomitization, and other diffusion-controlled processes. The results indicate that cation diffusion in calcite is relatively slow and cations are the rate-limiting diffusing species for the deformation of calcite and carbonate rocks. Application of the calcite-dolomite geothermometer to metamorphic assemblages will be constrained by cation diffusion and cooling rates. The direct measurement of Mg tracer diffusion in calcite indicates that dolomitization is unlikely to be accomplished by Mg diffusion in the solid state but by a recrystallization process.

  2. Treatment of Ruptured Ovarian Endometrioma with Extremely High CA 125, Moderately High CA 19-9 and CA 15-3 Level

    Directory of Open Access Journals (Sweden)

    Muzeyyen Duran

    2013-06-01

    Full Text Available In this case report, a ruptured ovarian endometrioma with a very high CA-125 level, moderately elevated CA 19-9, and CA 15-3 levels is presented. A 20 years old patient, complaining from pelvic pain, 5 cm adnexial mass was detected on left side. Biochemical examination was revealed very high CA-125 value (2556IU/ml, moderately elevated CA 19-9 (134IU/ml, and CA 15-3 (65IU/ml values. Laparoscopy was done and a ruptured ovarian endometrioma of 5 cm was seen during operation. After the total excision of the cyst, tumor markers fell rapidly. Very high CA-125 value, moderately elevated CA19-9, and CA 15-3 values can be seen in cases with ruptured endometrioma. In young patients, endometrioma must be considered firstly and laparoscopy should be applied instead of more invasive methods unless there was any finding or strong suspicion about malignancy.

  3. A significant but rather mild contribution of T286 autophosphorylation to Ca2+/CaM-stimulated CaMKII activity.

    Directory of Open Access Journals (Sweden)

    Steven J Coultrap

    Full Text Available BACKGROUND: Autophosphorylation of the Ca(2+/calmodulin (CaM-dependent protein kinase II (CaMKII at T286 generates partially Ca(2+/CaM-independent "autonomous" activity, which is thought to be required for long-term potentiation (LTP, a form of synaptic plasticity thought to underlie learning and memory. A requirement for T286 autophosphorylation also for efficient Ca(2+/CaM-stimulated CaMKII activity has been described, but remains controversial. METHODOLOGY/PRINCIPAL FINDINGS: In order to determine the contribution of T286 autophosphorylation to Ca(2+/CaM-stimulated CaMKII activity, the activity of CaMKII wild type and its phosphorylation-incompetent T286A mutant was compared. As the absolute activity can vary between individual kinase preparations, the activity was measured in six different extracts for each kinase (expressed in HEK-293 cells. Consistent with measurements on purified kinase (from a baculovirus/Sf9 cell expression system, CaMKII T286A showed a mildly but significantly reduced rate of Ca(2+/CaM-stimulated phosphorylation for two different peptide substrates (to ~75-84% of wild type. Additional slower CaMKII autophosphorylation at T305/306 inhibits stimulation by Ca(2+/CaM, but occurs only minimally for CaMKII wild type during CaM-stimulated activity assays. Thus, we tested if the T286A mutant may show more extensive inhibitory autophosphorylation, which could explain its reduced stimulated activity. By contrast, inhibitory autophosphorylation was instead found to be even further reduced for the T286A mutant under our assay conditions. On a side note, the phospho-T305 antibody showed some basal background immuno-reactivity also with non-phosphorylated CaMKII, as indicated by T305/306A mutants. CONCLUSIONS/SIGNIFICANCE: These results indicate that Ca(2+/CaM-stimulated CaMKII activity is mildly (~1.2-1.3fold further increased by additional T286 autophosphorylation, but that this autophosphorylation is not required for the major

  4. Control of ciliary motility by Ca sup 2+ : Integration of Ca sup 2+ -dependent functions and targets for Ca sup 2+ action

    Energy Technology Data Exchange (ETDEWEB)

    Evans, T.C.

    1988-01-01

    To identify functions that regulate Ca{sup 2+}-induced ciliary reversal in Paramecium, mutants defective in terminating depolarization-induced backward swimming were selected. Six independent recessive mutations (k-shy) comprising two complementation groups, k-shyA and k-shyB, were identified. All mutants exhibited prolonged backward swimming in depolarizing solutions. Voltage clamp studies revealed that mutant Ca{sup 2+} current amplitudes were reduced, but could be restored to wild type levels by EGTA injection. The recovery of the mutant Ca{sup 2+} current from Ca{sup 2+}-dependent inactivation, and the decay of the Ca{sup 2+}-dependent K{sup +} and Ca{sup 2+}-dependent Na{sup +} currents after depolarization were slow in k-shy compared to wild type. To identify protein targets of Ca{sup 2+} action, ciliary proteins that interact with calmodulin (CaM) were characterized. With a {sup 125}I-CaM blot assay, several CaM-binding proteins were identified including axonemal, soluble, and membrane-bound polypeptides. Competitive displacement studies with unlabeled Paramecium CaM, bovine CaM, and troponinC suggested that both protein types bind CaM with high affinity and specificity. To examine the presence of CaM-binding sites in intact axonemes, a filtration binding assay was developed.

  5. Clinical significance of detecting CEA, CA199, AFP, HCG, CA153, CA125 in postoperative treatment of patients with ovarian cancer

    Institute of Scientific and Technical Information of China (English)

    Xue Pan; Zhen-Hua Du

    2016-01-01

    Objective:To explore the clinical significance of carcinoembryonic antigen (CEA), carbohydrate antigen 199 (CA199), a tire protein (AFP), human chorionic gonadotropin (HCG), carbohydrate antigen 153 (CA153) and carbohydrate antigen 125 (CA125) in the postoperative treatment of patients with ovarian cancer.Methods:210 cases of patients with ovarian cancer after initial treatment from January 2015 to December 2015, 232 cases of patients with ovarian benign tumor and 250 cases of healthy women were selected, CEA, CA199, AFP, HCG, CA153 and CA125 levels were detected, and the levels after chemotherapy in patients with ovarian carcinoma were detected.Results:CEA, CA199, AFP, HCG, CA153 and CA125 levels in patients with ovarian cancer were (12.37±7.43) ng/mL, (84.04±26.96) U/mL, (37.46±9.47) μg/L, (110.54±35.51) IU/L, (51.23±9.20) U/mL and (64.36±42.68) U/mL, respectively, which were significantly higher than that in normal controls and patients with benign ovarian lesions, and were considered to be statistically significant. Chemotherapy after two cycles, CEA, CA199, AFP, HCG, CA153 and CA125 levels in patients with ovarian cancer were significantly lower than that before chemotherapy, and were considered to be statistically different. Chemotherapy after four cycles, CEA, CA199, AFP, HCG, CA153 and CA125 levels in patients with ovarian cancer continue to decrease, and were significantly lower than that of chemotherapy after two cycles, and had statistical differences.Conclusion:CEA, CA199, AFP, HCG, CA153 and CA125 can be used as important indicators for monitoring the chemotherapy effects, early recurrence and metastasis of ovarian cancer.

  6. Synaptotagmin-7 is a principal Ca2+ sensor for Ca2+ -induced glucagon exocytosis in pancreas

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Wei, Shun-Hui; Hoang, Dong Nhut

    2009-01-01

    abolished Ca(2+)-triggered glucagon secretion. Moreover, single-cell capacitance measurements confirmed that pancreatic alpha-cells lacking synaptotagmin-7 exhibited little Ca(2+)-induced exocytosis, whereas all other physiological and morphological parameters of the alpha-cells were normal. Our data thus...

  7. Investigation of the 42Ca(n, γ)43Ca reaction

    NARCIS (Netherlands)

    Gruppelaar, H.; Kamp, A.M.F. op den; Spits, A.M.J.

    1969-01-01

    Gamma rays from thermal-neutron capture in enriched 42Ca were investigated with Ge(Li) detectors. Gamma-gamma coincidence measurements were performed with a Ge(Li)---NaI detector combination. A decay scheme of 43Ca has been constructed containing 42 of the 47 observed γ-lines. The excitation energie

  8. Sulfide capacity of CaO-CaF2-SiO2 slags

    Science.gov (United States)

    Susaki, Katsujiro; Maeda, Masafumi; Sano, Nobuo

    1990-02-01

    The sulfide capacity C S 2- = (pct S2-) · ( P O 2/ P S 2)1/2) of CaO-CaF2-SiO2 slags saturated with CaO, 3CaO · SiO2 or 2CaOSiO2 was determined at 1200 °C, 1250 °C, 1300 °C, and 1350 °C by equilibrating molten slag, molten silver, and CO-CO2 gas mixtures. Higher sulfide capacities were obtained for CaO-saturated slags. A drastic decrease was observed in those values when the ratio pct CaO/pct SiO2 is less than 2. The sulfur partition between carbon-saturated iron melts and presently investigated slags was calculated by using the sulfide capacities obtained and the activity coefficient of sulfur in carbon-saturated iron, which was also experimentally determined. For slags saturated with CaO, partitions of sulfur as high as 10,000 were obtained at 1300 °C and 1350 °C. Correlations between the sulfide capacity and other basicity indexes such as carbonate capacity and theoretical optical basicity were also discussed.

  9. Multifaceted plasma membrane Ca(2+) pumps: From structure to intracellular Ca(2+) handling and cancer.

    Science.gov (United States)

    Padányi, Rita; Pászty, Katalin; Hegedűs, Luca; Varga, Karolina; Papp, Béla; Penniston, John T; Enyedi, Ágnes

    2016-06-01

    Plasma membrane Ca(2+) ATPases (PMCAs) are intimately involved in the control of intracellular Ca(2+) concentration. They reduce Ca(2+) in the cytosol not only by direct ejection, but also by controlling the formation of inositol-1,4,5-trisphosphate and decreasing Ca(2+) release from the endoplasmic reticulum Ca(2+) pool. In mammals four genes (PMCA1-4) are expressed, and alternative RNA splicing generates more than twenty variants. The variants differ in their regulatory characteristics. They localize into highly specialized membrane compartments and respond to the incoming Ca(2+) with distinct temporal resolution. The expression pattern of variants depends on cell type; a change in this pattern can result in perturbed Ca(2+) homeostasis and thus altered cell function. Indeed, PMCAs undergo remarkable changes in their expression pattern during tumorigenesis that might significantly contribute to the unbalanced Ca(2+) homeostasis of cancer cells. This article is part of a Special Issue entitled: Calcium and Cell Fate. Guest Editors: Jacques Haiech, Claus Heizmann, Joachim Krebs, Thierry Capiod and Olivier Mignen.

  10. (Meta)stable CaC{sub 2}; (Meta)stabiles CaC{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, J.; Dill, S.; Marzini, M.; Mayer, H.A.; Meyer, H.J. [Tuebingen Univ. (Germany). Inst. fuer Anorganische Chemie

    2001-05-01

    One out of four modifications of CaC{sub 2} is the so-called metastable calcium carbide, CaC{sub 2}-III, which was synthesized as pure material. It forms by heating monoclinic CaC{sub 2}-II (C2/c) above 150 C and remains stable after cooling down to room temperature. The structure was refined from X-ray powder patterns (C2/m, Z = 4, a = 722.6(1) pm, b = 385.26(7) pm, c = 737.6(1) pm, {beta} = 107.345(2) ). After grinding CaC{sub 2}-III transforms back into CaC{sub 2}-II. Heating CaC{sub 2}-III induces a reversible phase transition into the cubic modification (CaC{sub 2}-IV) at 460 C. Differences between the three different structures of CaC{sub 2} I-III, being stable at ambient conditions are also shown by {sup 13}C-MAS-NMR measurements, especially the presence of two distinct types of carbon atoms in the structure of the title compound. (orig.)

  11. Ca3Mn2O7.

    Science.gov (United States)

    Guiblin, Nicolas; Grebille, Dominique; Leligny, Henri; Martin, Christine

    2002-01-01

    The tricalcium dimanganese heptaoxide (Ca3Mn2O7) member of the Ruddlesden-Popper series Ca(n+1)Mn(n)O(3n+1), i.e. with n = 2, was previously reported with an I-centred tetragonal lattice [a(t) = 3.68 and c(t) = 19.57 A] by Fawcett, Sunstrom, Greenblatt, Croft & Ramanujachary [Chem. Mater. (1998), 10, 3643-3651]. It is now found to be orthorhombic, with an A-centred lattice [a = 5.2347 (6), b = 5.2421 (2) and c = 19.4177 (19) A]. The structure has been refined in space group A2(1)am using X-ray single-crystal diffraction data and assuming the existence of twin domains related by the (1-10) plane. A comparison with the basic perovskite structure CaMnO3 (n = infinity) is proposed.

  12. Calcium platinum aluminium, CaPtAl

    Directory of Open Access Journals (Sweden)

    Charles Fon Abi

    2011-10-01

    Full Text Available A preliminary X-ray study of CaPtAl has been reported previously by Hulliger [J. Alloys Compd (1993, 196, 225–228] based on X-ray powder diffraction data without structure refinement. With the present single-crystal X-ray study, we confirm the assignment of the TiNiSi type for CaPtAl, in a fully ordered inverse structure. All three atoms of the asymmetric unit have .m. site symmetry. The structure features a ∞3[AlPt] open framework with a fourfold coordination of Pt by Al atoms and vice versa. The Ca atoms are located in the large channels of the structure.

  13. Atom Trap Trace Analysis of Ca Isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Hoekstra, S., E-mail: hoekstra@fhi-berlin.mgp.de [Fritz-Haber Institut der Max-Planck Gesellschaft (Germany); Mollema, A. K.; Morgenstern, R.; Willmann, L.; Wilschut, H. W.; Hoekstra, R. [Rijksuniversiteit Groningen, Atomic Physics, KVI (Netherlands)

    2005-04-15

    In our experiment we aim at the detection of the rarest, naturally occuring calcium isotope 41Ca by means of atom trap trace analysis. On basis of single-atom detection of 46Ca our present sensitivity for 41Ca is estimated to be 1 atom per hour at an abundance of 10-12. To reach a sensitivity at the level of natural abundance, which is 10-14, we need to reduce atomic beam losses. To achieve this, optical compression of the atomic beam is a promising option. We use Monte Carlo Simulations to demonstrate that optical compression of the atomic beam increases throughput of the atomic beam as well as isotope selectivity.

  14. ASteCA - Automated Stellar Cluster Analysis

    CERN Document Server

    Perren, Gabriel I; Piatti, Andrés E

    2014-01-01

    We present ASteCA (Automated Stellar Cluster Analysis), a suit of tools designed to fully automatize the standard tests applied on stellar clusters to determine their basic parameters. The set of functions included in the code make use of positional and photometric data to obtain precise and objective values for a given cluster's center coordinates, radius, luminosity function and integrated color magnitude, as well as characterizing through a statistical estimator its probability of being a true physical cluster rather than a random overdensity of field stars. ASteCA incorporates a Bayesian field star decontamination algorithm capable of assigning membership probabilities using photometric data alone. An isochrone fitting process based on the generation of synthetic clusters from theoretical isochrones and selection of the best fit through a genetic algorithm is also present, which allows ASteCA to provide accurate estimates for a cluster's metallicity, age, extinction and distance values along with its unce...

  15. Anoxia-induced elevation of cytosolic Ca2+ concentration depends on different Ca2+ sources in rice and wheat protoplasts.

    Science.gov (United States)

    Yemelyanov, Vladislav V; Shishova, Maria F; Chirkova, Tamara V; Lindberg, Sylvia M

    2011-08-01

    The anoxia-dependent elevation of cytosolic Ca(2+) concentration, [Ca(2+)](cyt), was investigated in plants differing in tolerance to hypoxia. The [Ca(2+)](cyt) was measured by fluorescence microscopy in single protoplasts loaded with the calcium-fluoroprobe Fura 2-AM. Imposition of anoxia led to a fast (within 3 min) significant elevation of [Ca(2+)](cyt) in rice leaf protoplasts. A tenfold drop in the external Ca(2+) concentration (to 0.1 mM) resulted in considerable decrease of the [Ca(2+)](cyt) shift. Rice root protoplasts reacted upon anoxia with higher amplitude. Addition of plasma membrane (verapamil, La(3+) and EGTA) and intracellular membrane Ca(2+)-channel antagonists (Li(+), ruthenium red and cyclosporine A) reduced the anoxic Ca(2+)-accumulation in rice. Wheat protoplasts responded to anoxia by smaller changes of [Ca(2+)](cyt). In wheat leaf protoplasts, the amplitude of the Ca(2+)-shift little depended on the external level of Ca(2+). Wheat root protoplasts were characterized by a small shift of [Ca(2+)](cyt) under anoxia. Plasmalemma Ca(2+)-channel blockers had little effect on the elevation of cytosolic Ca(2+) in wheat protoplasts. Intact rice seedlings absorbed Ca(2+) from the external medium under anoxic treatment. On the contrary, wheat seedlings were characterized by leakage of Ca(2+). Verapamil abolished the Ca(2+) influx in rice roots and Ca(2+) efflux from wheat roots. Anoxia-induced [Ca(2+)](cyt) elevation was high particularly in rice, a hypoxia-tolerant species. In conclusion, both external and internal Ca(2+) stores are important for anoxic [Ca(2+)](cyt) elevation in rice, whereas the hypoxia-intolerant wheat does not require external sources for [Ca(2+)](cyt) rise. Leaf and root protoplasts similarly responded to anoxia, independent of their organ origin.

  16. Mitochondrial Ca(2+) uptake in skeletal muscle health and disease.

    Science.gov (United States)

    Zhou, Jingsong; Dhakal, Kamal; Yi, Jianxun

    2016-08-01

    Muscle uses Ca(2+) as a messenger to control contraction and relies on ATP to maintain the intracellular Ca(2+) homeostasis. Mitochondria are the major sub-cellular organelle of ATP production. With a negative inner membrane potential, mitochondria take up Ca(2+) from their surroundings, a process called mitochondrial Ca(2+) uptake. Under physiological conditions, Ca(2+) uptake into mitochondria promotes ATP production. Excessive uptake causes mitochondrial Ca(2+) overload, which activates downstream adverse responses leading to cell dysfunction. Moreover, mitochondrial Ca(2+) uptake could shape spatio-temporal patterns of intracellular Ca(2+) signaling. Malfunction of mitochondrial Ca(2+) uptake is implicated in muscle degeneration. Unlike non-excitable cells, mitochondria in muscle cells experience dramatic changes of intracellular Ca(2+) levels. Besides the sudden elevation of Ca(2+) level induced by action potentials, Ca(2+) transients in muscle cells can be as short as a few milliseconds during a single twitch or as long as minutes during tetanic contraction, which raises the question whether mitochondrial Ca(2+) uptake is fast and big enough to shape intracellular Ca(2+) signaling during excitation-contraction coupling and creates technical challenges for quantification of the dynamic changes of Ca(2+) inside mitochondria. This review focuses on characterization of mitochondrial Ca(2+) uptake in skeletal muscle and its role in muscle physiology and diseases.

  17. Electrochemical formation of Mg-Li-Ca alloys by codeposition of Mg, Li and Ca from LiCl-KCl-MgCl2-CaCl2 melts.

    Science.gov (United States)

    Yan, Yong De; Zhang, Mi Lin; Xue, Yun; Han, Wei; Cao, Dian Xue; Jing, Xiao Yan; He, Li Yi; Yuan, Yi

    2009-08-07

    This work presents electrochemical formation of Mg-Li-Ca alloys via codeposition of Mg, Li and Ca on a molybdenum electrode in KCl-LiCl-MgCl(2)-CaCl(2) melts at 943 K. Cyclic voltammograms (CVs) showed that the underpotential deposition (UPD) of calcium on pre-deposited magnesium leads to the formation of a liquid Mg-Ca alloy, and the succeeding underpotential deposition of lithium on pre-deposited Mg-Ca alloy leads to the formation of a liquid Mg-Li-Ca solution. Chronopotentiometric measurements indicated that the codepositon of Mg, Li and Ca occurs at current densities more negative than -0.31 A cm(-2) in LiCl-KCl-MgCl(2) (5 wt%) melts containing 1 wt% CaCl(2). Chronoamperograms demonstrated that the onset potential for the codeposition of Mg, Li and Ca is -2.200 V, and the codeposition of Mg, Li and Ca is formed when the applied potentials are more negative than -2.200 V. X-Ray diffraction (XRD) indicated that Mg-Li-Ca alloys with different phases were formed via galvanostatic electrolysis. The microstructures of typical alpha and beta phases of Mg-Li-Ca alloys were characterized by optical microscope (OM) and scanning electron microscopy (SEM). The analysis of energy dispersive spectrometry (EDS) showed that the element Ca mainly distributes along grain boundary in Mg-Li-Ca alloys. The results of inductively coupled plasma analysis determined that the chemical compositions of Mg-Li-Ca alloys correspond with the phase structures of XRD patterns, and the lithium and calcium contents of Mg-Li-Ca alloys depend on the concentrations of MgCl(2) and CaCl(2).

  18. CA19-9antigenlevelscandistinguishbetween benignandmalignantpancreaticobiliarydisease

    Institute of Scientific and Technical Information of China (English)

    Gareth Morris-Stiff; Mary Teli; Nicky Jardine; Malcolm CA Puntis

    2009-01-01

    BACKGROUND: CA19-9 is a carbohydrate tumor-associated antigen which is frequently upregulated in pancreatobiliary neoplasia. However, it may also be elevated in patients with jaundice in the absence of a tumor due to biliary obstruction, and in other non-hepato-pancreatico-biliary conditions. This study aimed to evaluate whether CA19-9 levels could accurately differentiate between benign and malignant pancreatobiliary disease. METHODS: All patients referred to a single surgeon for investigation of pancreaticobiliary disease in 2003 in whom a ifrm diagnosis had been established were included. For malignant disease, a histological diagnosis was required but for benign disease a ifrm radiological diagnosis was deemed adequate. The patients were divided into 4 categories:pancreatic adenocarcinoma (PCa); cholangiocarcinoma (CCa); chronic pancreatitis (CP) and biliary calculous disease (Calc). Bilirubin and alkaline phosphatase levels corresponding to the point of assessment of CA19-9 were also noted. RESULTS:  Final diagnoses were made of pancreatic adenocarcinoma (PCa, n=73), cholangiocarcinoma (CCa, n=19), ampullary carcinoma (Amp, n=7), neuroendocrine carcinoma (Neu, n=4), duodenal carcinoma (Duo, n=3), chronic pancreatitis (CP, n=115), and biliary calculous disease (Calc, n=27). Median CA19-9 levels (U/ml) were:PCa, 653;CCa, 408;Duo, 403;Calc, 27;CP, 19;Neu, 10.5;Amp, 8 (reference range: 0-37). The CA19-9 levels were signiifcantly greater for malignant than for benign disease, could differentiate PCa from CCa/Duo, and were signiifcantly higher in unresectable than in resectable PCa. The sensitivity, speciifcity, positive predictive value (PPV) and negative predictive value (NPV) for CA19-9 were 84.9%, 69.7%, 67.7%and 86.1%, respectively. A ROC analysis provided an area under the curve for CA19-9 of 0.871 (0.820-0.922), giving an optimal CA19-9 of 70.5 U/ml for differentiating benign from malignant pathology. Using this cut-off, the sensitivity was 82

  19. Hippocampal CA1 Ripples as Inhibitory Transients.

    Directory of Open Access Journals (Sweden)

    Paola Malerba

    2016-04-01

    Full Text Available Memories are stored and consolidated as a result of a dialogue between the hippocampus and cortex during sleep. Neurons active during behavior reactivate in both structures during sleep, in conjunction with characteristic brain oscillations that may form the neural substrate of memory consolidation. In the hippocampus, replay occurs within sharp wave-ripples: short bouts of high-frequency activity in area CA1 caused by excitatory activation from area CA3. In this work, we develop a computational model of ripple generation, motivated by in vivo rat data showing that ripples have a broad frequency distribution, exponential inter-arrival times and yet highly non-variable durations. Our study predicts that ripples are not persistent oscillations but result from a transient network behavior, induced by input from CA3, in which the high frequency synchronous firing of perisomatic interneurons does not depend on the time scale of synaptic inhibition. We found that noise-induced loss of synchrony among CA1 interneurons dynamically constrains individual ripple duration. Our study proposes a novel mechanism of hippocampal ripple generation consistent with a broad range of experimental data, and highlights the role of noise in regulating the duration of input-driven oscillatory spiking in an inhibitory network.

  20. Hippocampal CA1 Ripples as Inhibitory Transients.

    Science.gov (United States)

    Malerba, Paola; Krishnan, Giri P; Fellous, Jean-Marc; Bazhenov, Maxim

    2016-04-01

    Memories are stored and consolidated as a result of a dialogue between the hippocampus and cortex during sleep. Neurons active during behavior reactivate in both structures during sleep, in conjunction with characteristic brain oscillations that may form the neural substrate of memory consolidation. In the hippocampus, replay occurs within sharp wave-ripples: short bouts of high-frequency activity in area CA1 caused by excitatory activation from area CA3. In this work, we develop a computational model of ripple generation, motivated by in vivo rat data showing that ripples have a broad frequency distribution, exponential inter-arrival times and yet highly non-variable durations. Our study predicts that ripples are not persistent oscillations but result from a transient network behavior, induced by input from CA3, in which the high frequency synchronous firing of perisomatic interneurons does not depend on the time scale of synaptic inhibition. We found that noise-induced loss of synchrony among CA1 interneurons dynamically constrains individual ripple duration. Our study proposes a novel mechanism of hippocampal ripple generation consistent with a broad range of experimental data, and highlights the role of noise in regulating the duration of input-driven oscillatory spiking in an inhibitory network.

  1. 76 FR 20433 - California Disaster #CA-00169

    Science.gov (United States)

    2011-04-12

    ... ADMINISTRATION California Disaster CA-00169 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated 04/05/2011. Incident: Center Fire. Incident Period: 03/18/2011 through 03/20/2011. Effective Date:...

  2. 78 FR 55771 - California Disaster #CA-00207

    Science.gov (United States)

    2013-09-11

    ... ADMINISTRATION California Disaster CA-00207 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of CALIFORNIA dated 08/26/2013. Incident: Silver Fire. Incident Period: 08/07/2013 through 08/14/2013. Effective Date:...

  3. 76 FR 62132 - California Disaster #CA-00176

    Science.gov (United States)

    2011-10-06

    ... ADMINISTRATION California Disaster CA-00176 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated 09/29/2011. Incident: Canyon Fire. Incident Period: 09/04/2011 through 09/11/2011. Effective Date:...

  4. 78 FR 60366 - California Disaster #CA-00212

    Science.gov (United States)

    2013-10-01

    ... ADMINISTRATION California Disaster CA-00212 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated 09/24/2013. Incident: Clover Fire Incident Period: 09/09/2013 through 09/15/2013. Effective Date:...

  5. 77 FR 1971 - California Disaster #CA-00183

    Science.gov (United States)

    2012-01-12

    ... ADMINISTRATION California Disaster CA-00183 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated 01/05/2012. Incident: 1502 Golden Gate Fire. Incident Period: 12/22/2011. Effective Date:...

  6. 78 FR 39821 - California Disaster #CA-00202

    Science.gov (United States)

    2013-07-02

    ... ADMINISTRATION California Disaster CA-00202 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated 06/25/2013. Incident: Powerhouse Fire. Incident Period: 05/30/2013 through 06/11/2013. Effective Date:...

  7. 78 FR 77195 - California Disaster #CA-00214

    Science.gov (United States)

    2013-12-20

    ... ADMINISTRATION California Disaster CA-00214 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for the State of California (FEMA- 4158-DR), dated 12/13/2013. Incident: Rim Fire. Incident Period:...

  8. 76 FR 16029 - CALIFORNIA Disaster #CA-00165

    Science.gov (United States)

    2011-03-22

    ... ADMINISTRATION CALIFORNIA Disaster CA-00165 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of CALIFORNIA dated 03/16/2011. Incident: Garden Breeze Apartment Complex Fire. Incident Period: 02/20/2011. DATES:...

  9. 76 FR 79751 - California Disaster #CA-00181

    Science.gov (United States)

    2011-12-22

    ... ADMINISTRATION California Disaster CA-00181 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated 12/14/2011. Incident: Sequoia Apartment Complex Fire. Incident Period: 11/18/2011. Effective Date:...

  10. Numerical model of Ca(OH)

    NARCIS (Netherlands)

    Koster, T.; Peelen, W.; Larbi, J.; Rooij, M. de; Polder, R.

    2010-01-01

    A mathematical model is being developed to describe a repair method in concrete, called cathodic protection (CP). The model is in principle also useful to describe electrodeposition in concrete, e.g. the process of re-precipitation of Ca(OH)2 invoked by an electrical current. In CP, the c

  11. 75 FR 8414 - California Disaster # CA-00150

    Science.gov (United States)

    2010-02-24

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00150 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated...

  12. 76 FR 7622 - California Disaster #CA-00162

    Science.gov (United States)

    2011-02-10

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00162 AGENCY: U.S. Small Business Administration. ] ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated...

  13. 77 FR 61815 - California Disaster #CA-00190

    Science.gov (United States)

    2012-10-11

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00190 AGENCY: U.S. Small Business Administration. ACTION: Amendment 1. SUMMARY: This is an amendment of the Administrative declaration of a disaster for the State of...

  14. 76 FR 38263 - California Disaster #CA-00172

    Science.gov (United States)

    2011-06-29

    ... From the Federal Register Online via the Government Publishing Office Small Business Administration California Disaster CA-00172 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  15. 75 FR 17792 - California Disaster # CA-00150

    Science.gov (United States)

    2010-04-07

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00150 AGENCY: U.S. Small Business Administration. ACTION: Amendment 1. SUMMARY: This is an amendment of the Administrative declaration of disaster for the State of...

  16. 76 FR 5856 - California Disaster #CA-00164

    Science.gov (United States)

    2011-02-02

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00164 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  17. 75 FR 13144 - California Disaster #CA-00151

    Science.gov (United States)

    2010-03-18

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00151 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  18. 76 FR 11307 - California Disaster #CA-00162

    Science.gov (United States)

    2011-03-01

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00162 AGENCY: U.S. Small Business Administration. ACTION: Amendment 1. SUMMARY: This is an amendment of the Administrative declaration of a disaster for the State of...

  19. 75 FR 68848 - California Disaster #CA-00160

    Science.gov (United States)

    2010-11-09

    ... [Federal Register Volume 75, Number 216 (Tuesday, November 9, 2010)] [Notices] [Pages 68848-68849] [FR Doc No: 2010-28201] SMALL BUSINESS ADMINISTRATION [Disaster Declaration 12370 and 12371] California Disaster CA-00160 AGENCY: U.S. Small Business Administration. [[Page 68849

  20. 76 FR 18614 - California Disaster #CA-00167

    Science.gov (United States)

    2011-04-04

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00167 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated...

  1. 76 FR 80446 - California Disaster #CA-00182

    Science.gov (United States)

    2011-12-23

    ... [Federal Register Volume 76, Number 247 (Friday, December 23, 2011)] [Notices] [Pages 80446-80447] [FR Doc No: 2011-32952] SMALL BUSINESS ADMINISTRATION [Disaster Declaration 12967 and 12968] California Disaster CA-00182 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is...

  2. 76 FR 24555 - California Disaster #CA-00171

    Science.gov (United States)

    2011-05-02

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00171 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of CALIFORNIA dated...

  3. 77 FR 58901 - California Disaster #CA-00190

    Science.gov (United States)

    2012-09-24

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00190 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated...

  4. 75 FR 27846 - California Disaster # CA-00155

    Science.gov (United States)

    2010-05-18

    ... [Federal Register Volume 75, Number 95 (Tuesday, May 18, 2010)] [Notices] [Page 27846] [FR Doc No: 2010-11746] SMALL BUSINESS ADMINISTRATION [Disaster Declaration 12166 and 12167] California Disaster CA-00155 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of...

  5. 75 FR 69733 - California Disaster #CA-00161

    Science.gov (United States)

    2010-11-15

    ... [Federal Register Volume 75, Number 219 (Monday, November 15, 2010)] [Notices] [Page 69733] [FR Doc No: 2010-28587] SMALL BUSINESS ADMINISTRATION [Disaster Declaration 12373 and 12374] California Disaster CA-00161 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice...

  6. 75 FR 22872 - California Disaster # CA-00154

    Science.gov (United States)

    2010-04-30

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION California Disaster CA-00154 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of California dated...

  7. literacy.ca EXPRESS. April 2010

    Science.gov (United States)

    Movement for Canadian Literacy, 2010

    2010-01-01

    This issue of "literacy.ca EXPRESS" focuses on poverty. The articles included in this issue are: (1) Poverty Overview; (2) Tony's Story; (3) LAN (Learner Advisory Network) Member's Story (Dianne Smith); (4) Linking Adult Literacy to Poverty Reduction; (5) MCL (Movement for Canadian Literacy) Update; (6) Highlights from the LAN; (7) Good…

  8. Ca(2+)-activated chloride channel activity during Ca(2+) alternans in ventricular myocytes.

    Science.gov (United States)

    Kanaporis, Giedrius; Blatter, Lothar A

    2016-11-01

    Cardiac alternans, defined beat-to-beat alternations in contraction, action potential (AP) morphology or cytosolic Ca transient (CaT) amplitude, is a high risk indicator for cardiac arrhythmias. We investigated mechanisms of cardiac alternans in single rabbit ventricular myocytes. CaTs were monitored simultaneously with membrane currents or APs recorded with the patch clamp technique. A strong correlation between beat-to-beat alternations of AP morphology and CaT alternans was observed. During CaT alternans application of voltage clamp protocols in form of pre-recorded APs revealed a prominent Ca(2+)-dependent membrane current consisting of a large outward component coinciding with AP phases 1 and 2, followed by an inward current during AP repolarization. Approximately 85% of the initial outward current was blocked by Cl(-) channel blocker DIDS or lowering external Cl(-) concentration identifying it as a Ca(2+)-activated Cl(-) current (ICaCC). The data suggest that ICaCC plays a critical role in shaping beat-to-beat alternations in AP morphology during alternans.

  9. DA-6034 Induces [Ca(2+)]i Increase in Epithelial Cells.

    Science.gov (United States)

    Yang, Yu-Mi; Park, Soonhong; Ji, Hyewon; Kim, Tae-Im; Kim, Eung Kweon; Kang, Kyung Koo; Shin, Dong Min

    2014-04-01

    DA-6034, a eupatilin derivative of flavonoid, has shown potent effects on the protection of gastric mucosa and induced the increases in fluid and glycoprotein secretion in human and rat corneal and conjunctival cells, suggesting that it might be considered as a drug for the treatment of dry eye. However, whether DA-6034 induces Ca(2+) signaling and its underlying mechanism in epithelial cells are not known. In the present study, we investigated the mechanism for actions of DA-6034 in Ca(2+) signaling pathways of the epithelial cells (conjunctival and corneal cells) from human donor eyes and mouse salivary gland epithelial cells. DA-6034 activated Ca(2+)-activated Cl(-) channels (CaCCs) and increased intracellular calcium concentrations ([Ca(2+)]i) in primary cultured human conjunctival cells. DA-6034 also increased [Ca(2+)]i in mouse salivary gland cells and human corneal epithelial cells. [Ca(2+)]i increase of DA-6034 was dependent on the Ca(2+) entry from extracellular and Ca(2+) release from internal Ca(2+) stores. Interestingly, these effects of DA-6034 were related to ryanodine receptors (RyRs) but not phospholipase C/inositol 1,4,5-triphosphate (IP3) pathway and lysosomal Ca(2+) stores. These results suggest that DA-6034 induces Ca(2+) signaling via extracellular Ca(2+) entry and RyRs-sensitive Ca(2+) release from internal Ca(2+) stores in epithelial cells.

  10. Cenozoic seawater Sr/Ca evolution

    Science.gov (United States)

    Sosdian, Sindia M.; Lear, Caroline H.; Tao, Kai; Grossman, Ethan L.; O'Dea, Aaron; Rosenthal, Yair

    2012-10-01

    Records of seawater chemistry help constrain temporal variations in geochemical processes that impact the global carbon cycle and climate through Earth's history. Here we reconstruct Cenozoic seawater Sr/Ca (Sr/Casw) using fossil Conus and turritellid gastropod Sr/Ca. Combined with an oxygen isotope paleotemperature record from the same samples, the gastropod record suggests that Sr/Caswwas slightly higher in the Eocene (˜11.4 ± 3 mmol/mol) than today (˜8.54 mmol/mol) and remained relatively stable from the mid- to late Cenozoic. We compare our gastropod Cenozoic Sr/Casw record with a published turritellid gastropod Sr/Casw record and other published biogenic (benthic foraminifera, fossil fish teeth) and inorganic precipitate (calcite veins) Sr/Caswrecords. Once the uncertainties with our gastropod-derived Sr/Casw are taken into account the Sr/Casw record agrees reasonably well with biogenic Sr/Caswrecords. Assuming a seawater [Ca] history derived from marine evaporite inclusions, all biogenic-based Sr/Casw reconstructions imply decreasing seawater [Sr] through the Cenozoic, whereas the calcite vein Sr/Casw reconstruction implies increasing [Sr] through the Cenozoic. We apply a simple geochemical model to examine the implications of divergence among these seawater [Sr] reconstructions and suggest that the interpretation and uncertainties associated with the gastropod and calcite vein proxies need to be revisited. Used in conjunction with records of carbonate depositional fluxes, our favored seawater Sr/Ca scenarios point to a significant increase in the proportion of aragonite versus calcite deposition in shelf sediments from the Middle Miocene, coincident with the proliferation of coral reefs. We propose that this occurred at least 10 million years after the seawater Mg/Ca threshold was passed, and was instead aided by declining levels of atmospheric carbon dioxide.

  11. Serum concentrations of the biomarkers CA125, CA15-3, CA72-4, tPSA and PAPP-A in natural and stimulated ovarian cycles

    Directory of Open Access Journals (Sweden)

    Melissa Stemp

    2014-06-01

    Conclusion: Ovarian stimulation reduced serum PAPP‐A levels, CA125 and CA15‐3 levels were generally unaffected by ovarian stimulation but displayed cyclical changes throughout both natural and stimulated cycles, whilst tPSA and CA72-4 were not affected by the stage of the cycle or ovarian stimulation.

  12. Feedforward inhibition underlies the propagation of cholinergically induced gamma oscillations from hippocampal CA3 to CA1.

    Science.gov (United States)

    Zemankovics, Rita; Veres, Judit M; Oren, Iris; Hájos, Norbert

    2013-07-24

    Gamma frequency (30-80 Hz) oscillations are implicated in memory processing. Such rhythmic activity can be generated intrinsically in the CA3 region of the hippocampus from where it can propagate to the CA1 area. To uncover the synaptic mechanisms underlying the intrahippocampal spread of gamma oscillations, we recorded local field potentials, as well as action potentials and synaptic currents in anatomically identified CA1 and CA3 neurons during carbachol-induced gamma oscillations in mouse hippocampal slices. The firing of the vast majority of CA1 neurons and all CA3 neurons was phase-coupled to the oscillations recorded in the stratum pyramidale of the CA1 region. The predominant synaptic input to CA1 interneurons was excitatory, and their discharge followed the firing of CA3 pyramidal cells at a latency indicative of monosynaptic connections. Correlation analysis of the input-output characteristics of the neurons and local pharmacological block of inhibition both agree with a model in which glutamatergic CA3 input controls the firing of CA1 interneurons, with local pyramidal cell activity having a minimal role. The firing of phase-coupled CA1 pyramidal cells was controlled principally by their inhibitory inputs, which dominated over excitation. Our results indicate that the synchronous firing of CA3 pyramidal cells rhythmically recruits CA1 interneurons and that this feedforward inhibition generates the oscillatory activity in CA1. These findings identify distinct synaptic mechanisms underlying the generation of gamma frequency oscillations in neighboring hippocampal subregions.

  13. Ca2+ signals regulate mitochondrial metabolism by stimulating CREB-mediated expression of the mitochondrial Ca2+ uniporter gene MCU.

    Science.gov (United States)

    Shanmughapriya, Santhanam; Rajan, Sudarsan; Hoffman, Nicholas E; Zhang, Xueqian; Guo, Shuchi; Kolesar, Jill E; Hines, Kevin J; Ragheb, Jonathan; Jog, Neelakshi R; Caricchio, Roberto; Baba, Yoshihiro; Zhou, Yandong; Kaufman, Brett A; Cheung, Joseph Y; Kurosaki, Tomohiro; Gill, Donald L; Madesh, Muniswamy

    2015-03-03

    Cytosolic Ca2+ signals, generated through the coordinated translocation of Ca2+ across the plasma membrane (PM) and endoplasmic reticulum (ER) membrane, mediate diverse cellular responses. Mitochondrial Ca2+ is important for mitochondrial function, and when cytosolic Ca2+ concentration becomes too high, mitochondria function as cellular Ca2+ sinks. By measuring mitochondrial Ca2+ currents, we found that mitochondrial Ca2+ uptake was reduced in chicken DT40 B lymphocytes lacking either the ER-localized inositol trisphosphate receptor (IP3R), which releases Ca2+ from the ER, or Orai1 or STIM1, components of the PM-localized Ca2+ -permeable channel complex that mediates store-operated calcium entry (SOCE) in response to depletion of ER Ca2+ stores. The abundance of MCU, the pore-forming subunit of the mitochondrial Ca2+ uniporter, was reduced in cells deficient in IP3R, STIM1, or Orai1. Chromatin immunoprecipitation and promoter reporter analyses revealed that the Ca2+ -regulated transcription factor CREB (cyclic adenosine monophosphate response element-binding protein) directly bound the MCU promoter and stimulated expression. Lymphocytes deficient in IP3R, STIM1, or Orai1 exhibited altered mitochondrial metabolism, indicating that Ca2+ released from the ER and SOCE-mediated signals modulates mitochondrial function. Thus, our results showed that a transcriptional regulatory circuit involving Ca2+ -dependent activation of CREB controls the Ca2+ uptake capability of mitochondria and hence regulates mitochondrial metabolism.

  14. The alterations of Ca2+/calmodulin/CaMKII/CaV1.2 signaling in experimental models of Alzheimer's disease and vascular dementia.

    Science.gov (United States)

    Min, Dongyu; Guo, Feng; Zhu, Shu; Xu, Xiaoxue; Mao, Xiaoyuan; Cao, Yonggang; Lv, Xintong; Gao, Qinghua; Wang, Lei; Chen, Tianbao; Shaw, Chris; Hao, Liying; Cai, Jiqun

    2013-03-22

    The two critical forms of dementia are Alzheimer's disease (AD) and vascular dementia (VD). The alterations of Ca(2+)/calmodulin/CaMKII/CaV1.2 signaling in AD and VD have not been well elucidated. Here we have demonstrated changes in the levels of CaV1.2, calmodulin, p-CaMKII, p-CREB and BDNF proteins by Western blot analysis and the co-localization of p-CaMKII/CaV1.2 by double-labeling immunofluorescence in the hippocampus of APP/PS1 mice and VD gerbils. Additionally, expression of these proteins and intracellular calcium levels were examined in cultured neurons treated with Aβ1-42. The expression of CaV1.2 protein was increased in VD gerbils and in cultured neurons but decreased in APP/PS1 mice; the expression of calmodulin protein was increased in APP/PS1 mice and VD gerbils; levels of p-CaMKII, p-CREB and BDNF proteins were decreased in AD and VD models. The number of neurons in which p-CaMKII and CaV1.2 were co-localized, was decreased in the CA1 and CA3 regions in two models. Intracellular calcium was increased in the cultured neurons treated with Aβ1-42. Collectively, our results suggest that the alterations in CaV1.2, calmodulin, p-CaMKII, p-CREB and BDNF can be reflective of an involvement in the impairment in memory and cognition in AD and VD models.

  15. Ca2+ dialogue between acidic vesicles and ER.

    Science.gov (United States)

    Morgan, Anthony J

    2016-04-15

    Extracellular stimuli evoke the synthesis of intracellular second messengers, several of which couple to the release of Ca(2+)from Ca(2+)-storing organelles via activation of cognate organellar Ca(2+)-channel complexes. The archetype is the inositol 1,4,5-trisphosphate (IP3) and IP3receptor (IP3R) on the endoplasmic reticulum (ER). A less understood, parallel Ca(2+)signalling cascade is that involving the messenger nicotinic acid adenine dinucleotide phosphate (NAADP) that couples to Ca(2+)release from acidic Ca(2+)stores [e.g. endo-lysosomes, secretory vesicles, lysosome-related organelles (LROs)]. NAADP-induced Ca(2+)release absolutely requires organellar TPCs (two-pore channels). This review discusses how ER and acidic Ca(2+)stores physically and functionally interact to generate and shape global and local Ca(2+)signals, with particular emphasis on the two-way dialogue between these two organelles.

  16. Ca2+-binding protein-1 facilitates and forms a postsynaptic complex with Cav1.2 (L-type) Ca2+ channels.

    Science.gov (United States)

    Zhou, Hong; Kim, Seong-Ah; Kirk, Elizabeth A; Tippens, Alyssa L; Sun, Hong; Haeseleer, Françoise; Lee, Amy

    2004-05-12

    Ca2+-binding protein-1 (CaBP1) is a Ca2+-binding protein that is closely related to calmodulin (CaM) and localized in somatodendritic regions of principal neurons throughout the brain, but how CaBP1 participates in postsynaptic Ca2+ signaling is not known. Here, we describe a novel role for CaBP1 in the regulation of Ca2+ influx through Ca(v)1.2 (L-type) Ca2+ channels. CaBP1 interacts directly with the alpha1 subunit of Ca(v)1.2 at sites that also bind CaM. CaBP1 binding to one of these sites, the IQ domain, is Ca2+ dependent and competitive with CaM binding. The physiological significance of this interaction is supported by the association of Ca(v)1.2 and CaBP1 in postsynaptic density fractions purified from rat brain. Moreover, in double-label immunofluorescence experiments, CaBP1 and Ca(v)1.2 colocalize in numerous cell bodies and dendrites of neurons, particularly in pyramidal cells in the CA3 region of the hippocampus and in the dorsal cortex. In electrophysiological recordings of cells transfected with Ca(v)1.2, CaBP1 greatly prolonged Ca2+ currents, prevented Ca2+-dependent inactivation, and caused Ca2+-dependent facilitation of currents evoked by step depolarizations and repetitive stimuli. These effects contrast with those of CaM, which promoted strong Ca2+-dependent inactivation of Ca(v)1.2 with these same voltage protocols. Our findings reveal how Ca2+-binding proteins, such as CaM and CaBP1, differentially adjust Ca2+ influx through Ca(v)1.2 channels, which may specify diverse modes of Ca2+ signaling in neurons.

  17. Reduction of Ca2+-transporting systems in memory T cells.

    Science.gov (United States)

    Sigova, A A; Dedkova, E N; Zinchenko, V P; Litvinov, I S

    2000-01-01

    Antigen-specific B and T lymphocytes make up the material grounds of immune memory, their main functional distinction from the so-called "naive" cells is due to the rapid and enhanced response to the antigen-pathogen. An essential distinction between the memory and naive T cells is different sensitivity of these two subpopulations of T lymphocytes to Ca2+-ionophores. Comparative analysis of Ca2+ responses of the immune memory T lymphocytes and naive T cells of mouse CBA/J line to the addition of Ca2+-mobilizing agents concanavalin A, thapsigargin, and ionomycin was carried out. These compounds in concentrations increasing [Ca2+]i in naive cells had no effect on [Ca2+]i in memory cells. Thus, the Ca2+ entrance into memory cells was not activated by exhaustion of intracellular resources. Estimation of intracellular resources of Ca2+, mobilized by ionomycin and thapsigargin in Ca2+ free medium has shown the absence in memory T cells of the intracellular Ca2+ pool, which may be one of factors of their resistance to ionophores. Reduction of the system of Ca2+ influx into memory T cells was shown using the SH-reagent thimerosal. Memory T cells appear to be resistant to "Ca2+ -paradox." Their incubation with 0.5 mM EDTA in the presence or absence of Ca2+ -mobilizing compounds followed by addition of 2 mM CaCl2 did not result in induction of Ca2+ influx into these cells.

  18. Generation and behavior characterization of CaMKIIβ knockout mice.

    Directory of Open Access Journals (Sweden)

    Adam D Bachstetter

    Full Text Available The calcium/calmodulin-dependent protein kinase II (CaMKII is abundant in the brain, where it makes important contributions to synaptic organization and homeostasis, including playing an essential role in synaptic plasticity and memory. Four genes encode isoforms of CaMKII (α, β, δ, γ, with CaMKIIα and CaMKIIβ highly expressed in the brain. Decades of molecular and cellular research, as well as the use of a large number of CaMKIIα mutant mouse lines, have provided insight into the pivotal roles of CaMKIIα in brain plasticity and cognition. However, less is known about the CaMKIIβ isoform. We report the development and extensive behavioral and phenotypic characterization of a CaMKIIβ knockout (KO mouse. The CaMKIIβ KO mouse was found to be smaller at weaning, with an altered body mass composition. The CaMKIIβ KO mouse showed ataxia, impaired forelimb grip strength, and deficits in the rotorod, balance beam and running wheel tasks. Interestingly, the CaMKIIβ KO mouse exhibited reduced anxiety in the elevated plus maze and open field tests. The CaMKIIβ KO mouse also showed cognitive impairment in the novel object recognition task. Our results provide a comprehensive behavioral characterization of mice deficient in the β isoform of CaMKII. The neurologic phenotypes and the construction of the genotype suggest the utility of this KO mouse strain for future studies of CaMKIIβ in brain structure, function and development.

  19. Precise half-life measurements for $^{38}$Ca and $^{39}$Ca

    CERN Document Server

    Blank, B; Demonchy, C-E; Borge, M J G; Matea, I; Munoz, F; Huikari, J; Dominguez-Reyes, R; Plaisir, C; Sturm, S; Canchel, G; Delahaye, P; Audirac, L; Fraile, L M; Serani, L; Lunney, D; Pedroza, J-L; Bey, A; Souin, J; Hui, Tran Trong; Delalee, F; Tengblad, O; Wenander, F

    2010-01-01

    The half-lives of Ca-38 and Ca-39 have been measured at ISOLDE of CERN. The REXTRAP facility was used to prepare ultra-clean samples of radioactive nuclei for precision decay spectroscopy. Ca-38 is one of the T-z = -1, 0(+). 0(+) beta-emitting nuclides used to determine the vector coupling constant of the weak interaction and the V-ud quark-mixing matrix element. The result obtained, T-1/2 = 443.8(19) ms, is four times more precise than the average of previous measurements. For Ca-39, a half-life of T-1/2 = 860.7(10) ms is obtained, a result in agreement with the average value from the literature.

  20. Fabrication aspects of PLA-CaP/PLGA-CaP composites for orthopedic applications: a review.

    Science.gov (United States)

    Zhou, Huan; Lawrence, Joseph G; Bhaduri, Sarit B

    2012-07-01

    For several decades, composites made of polylactic acid-calcium phosphates (PLA-CaP) and polylactic acid-co-glycolic acid-calcium phosphates (PLGA-CaP) have seen widespread uses in orthopedic applications. This paper reviews the fabrication aspects of these composites, following the ubiquitous materials science approach by studying "processing-structure-property" correlations. Various fabrication processes such as microencapsulation, phase separation, electrospinning, supercritical gas foaming, etc., are reviewed, with specific examples of their applications in fabricating these composites. The effect of the incorporation of CaP materials on the mechanical and biological performance of PLA/PLGA is addressed. In addition, this paper describes the state of the art on challenges and innovations concerning CaP dispersion, incorporation of biomolecules/stem cells and long-term degradation of the composites.

  1. Prenatal morphine exposure reduces pyramidal neurons in CA1, CA2 and CA3 subfields of mice hippocampus

    Directory of Open Access Journals (Sweden)

    Soraya Ghafari

    2014-03-01

    Full Text Available Objective(s:This study was carried out to evaluate the effect of maternal morphine exposure during gestational and lactation period on pyramidal neurons of hippocampus in 18 and 32 day mice offspring. Materials and Methods: Thirty female mice were randomly allocated into cases and controls. In case group, animals received morphinesulfate 10 mg/kg.body weight intraperitoneally during 7 days before mating, gestational period (GD 0-21, 18 and 32 days after delivery in the experimental groups. The control animals received an equivalent volume of normal saline. Cerebrum of six offsprings in each group was removed and stained with cresyl violet and a monoclonal antibody NeuN for immunohistochemical detection of surviving pyramidal neurons. Quantitative computer-assisted morphometric study was done on hippocampus. Results: The number of pyramidal neurons in CA1, CA2 and CA3 in treated groups was significantly reduced in postnatal day 18 and 32 (P18, P32 compared to control groups (P

  2. RNAi knockdown of PIK3CA preferentially inhibits invasion of mutant PIK3CA cells

    Institute of Scientific and Technical Information of China (English)

    Xin-Ke Zhou; Sheng-Song Tang; Gao Yi; Min Hou; Jin-Hui Chen; Bo Yang; Ji-Fang Liu; Zhi-Min He

    2011-01-01

    AIM: To explore the effects of siRNA silencing of PIK3CA on proliferation, migration and invasion of gastric cancer cells and to investigate the underlying mechanisms.METHODS: The mutation of PIK3CA in exons 9 and 20 of gastric cancer cell lines HGC-27, SGC-7901, BGC-823, MGC-803 and MKN-45 was screened by poly-merase chain reaction (PCR) followed by sequencing. BGC-823 cells harboring no mutations in either of the exons, and HGC-27 cells containing PIK3CA mutations were employed in the current study. siRNA targeting PIK3CA was chemically synthesized and was transfect-ed into these two cell lines in vitro. mRNA and protein expression of PIK3CA were detected by real-time PCR and Western blotting, respectively. We also measured phosphorylation of a serine/threonine protein kinase (Akt) using Western blotting. The proliferation, migra-tion and invasion of these cells were examined sepa-rately by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltet-razolium bromide (MTT), wound healing and Transwell chambers assay.RESULTS: The siRNA directed against PIK3CA effec-tively led to inhibition of both endogenous mRNA and protein expression of PIK3CA, and thus significantly down-regulated phosphorylation of Akt (P < 0.05). Furthermore, simultaneous silencing of PIK3CA result-ed in an obvious reduction in tumor cell proliferation activity, migration and invasion potential (P < 0.01). Intriguing, mutant HGC-27 cells exhibited stronger invasion ability than that shown by wild-type BGC-823 cells. Knockdown of PIK3CA in mutant HGC-27 cells contributed to a reduction in cell invasion to a greater extent than in non-mutant BGC-823 cells.CONCLUSION: siRNA mediated targeting of PIK3CA may specifically knockdown the expression of PIK3CA in gastric cancer cells, providing a potential implication for therapy of gastric cancer.

  3. Glutamate receptor activation in cultured cerebellar granule cells increases cytosolic free Ca2+ by mobilization of cellular Ca2+ and activation of Ca2+ influx

    DEFF Research Database (Denmark)

    Bouchelouche, P; Belhage, B; Frandsen, A;

    1989-01-01

    The Ca2+ sensitive fluorescent probe, fura-2 has been used to monitor cytosolic free calcium levels in mature primary cultures of cerebellar granule cells during exposure to L-glutamate and other excitatory amino acids: quisqualate (QA) kainate (KA) and N-methyl-D-aspartate (NMDA). Glutamate...... at micromolar concentrations produced a prompt and dose-related increase in the intracellular concentration of free Ca2+, ([Ca2+]i), whereas QA, KA and NMDA had no effect. This increase was also seen in the absence of extracellular Ca2+, suggesting that L-glutamate promotes mobilization of Ca2+ from...

  4. Progressive alterations of hippocampal CA3-CA1 synapses in an animal model of depression.

    Science.gov (United States)

    Qiao, Hui; An, Shu-Cheng; Ren, Wei; Ma, Xin-Ming

    2014-12-15

    Major depressive disorder is the most prevalent psychiatric condition, but the cellular and molecular mechanisms underlying this disorder are largely unknown, although multiple hypotheses have been proposed. The aim of this study was to characterize the progressive alteration of neuronal plasticity in the male rat hippocampus during depression induced by chronic unpredictable mild stress (CUMS), an established animal model of depression. The data in the hippocampus were collected on days 7, 14 and 21 after the onset of three-week CUMS. When analyzed on day 21, three-week CUMS induced typically depressive-like behaviors, impaired LTP induction, and decreased basal synaptic transmission at hippocampal CA3-CA1 synapses recorded in vivo, which was accompanied by decreased density of dendritic spines in CA1 and CA3 pyramidal neurons. The levels of both Kalirin-7 and brain-derived neurotrophic factor (BDNF) in the hippocampus were decreased at the same time. On day 14 (middle phase), some depressive-like behaviors were observed, which was accompanied by depressed basal synaptic transmission and enhanced LTP induction at the CA3-CA1 synapses. However, BDNF expression was decreased without alteration of Kalirin7 expression in comparison with no-stress control. Depressed basal synaptic transmission occurred in the middle phase of CUMS may contribute to decreased expression of BDNF. On day 7, depressive-like behaviors were not observed, and LTP induction, spine density, Kalirin-7 and BDNF expression were not altered by CUMS in comparison with no-stress control. These results showed that the functional changes at CA3-CA1synapses occurred earlier than the structural alteration during three-week CUMS as a strategy of neural adaptation, and rats required three weeks to develop depressive-like behaviors during CUMS. Our results suggest an important role of Kalirin-7 in CUMS-mediated alterations in spine density, synaptic function and overall depressive-like behaviors on day 21.

  5. The Reliability of Highly Elevated CA 19-9 Levels

    Directory of Open Access Journals (Sweden)

    B. R. Osswald

    1993-01-01

    Full Text Available CA 19-9 is used as a tumour marker of the upper gastrointestinal tract. However, extremely elevated CA 19-9 levels are found also in patients with benign diseases. Cholestasis was present in 97.1 % of patients with high elevated CA 19-9, independent of their primary disease. 50% of patients with non-malignant diseases and increased CA 19-9 levels showed liver cirrhosis, cholecystitis, pancreatitis and/or hepatitis. In 8.8% no explanation was found for the extremely high CA 19-9 level. The results provide evidence of different factors influencing the CA 19-9 level.

  6. Endo-lysosomal TRP mucolipin-1 channels trigger global ER Ca2+ release and Ca2+ influx

    Science.gov (United States)

    Kilpatrick, Bethan S.; Yates, Elizabeth; Grimm, Christian; Schapira, Anthony H.

    2016-01-01

    ABSTRACT Transient receptor potential (TRP) mucolipins (TRPMLs), encoded by the MCOLN genes, are patho-physiologically relevant endo-lysosomal ion channels crucial for membrane trafficking. Several lines of evidence suggest that TRPMLs mediate localised Ca2+ release but their role in Ca2+ signalling is not clear. Here, we show that activation of endogenous and recombinant TRPMLs with synthetic agonists evoked global Ca2+ signals in human cells. These signals were blocked by a dominant-negative TRPML1 construct and a TRPML antagonist. We further show that, despite a predominant lysosomal localisation, TRPML1 supports both Ca2+ release and Ca2+ entry. Ca2+ release required lysosomal and ER Ca2+ stores suggesting that TRPMLs, like other endo-lysosomal Ca2+ channels, are capable of ‘chatter’ with ER Ca2+ channels. Our data identify new modalities for TRPML1 action. PMID:27577094

  7. Neuronal Ca(2+) dyshomeostasis in Huntington disease.

    Science.gov (United States)

    Giacomello, Marta; Oliveros, Juan C; Naranjo, Jose R; Carafoli, Ernesto

    2013-01-01

    The expansion of the N-terminal poly-glutamine tract of the huntingtin (Htt) protein is responsible for Huntington disease (HD). A large number of studies have explored the neuronal phenotype of HD, but the molecular aethiology of the disease is still very poorly understood. This has hampered the development of an appropriate therapeutical strategy to at least alleviate its symptoms. In this short review, we have focused our attention on the alteration of a specific cellular mechanism common to all HD models, either genetic or induced by treatment with 3-NPA, i.e. the cellular dyshomeostasis of Ca(2+). We have highlighted the direct and indirect (i.e. transcriptionally mediated) effects of mutated Htt on the maintenance of the intracellular Ca(2+) balance, the correct modulation of which is fundamental to cell survival and the disturbance of which plays a key role in the death of the cell.

  8. Conversation Analysis (CA in Primary School Classrooms

    Directory of Open Access Journals (Sweden)

    Alberto Fajardo

    2008-12-01

    Full Text Available Although CA deals with all kinds of talk produced in natural contexts, this study focuses its interest on the talk produced in some primary school classrooms. It attempts to develop the construct that CA should move significantly ahead to more practical grounds where its detailed and isolated description causes some effect in improving foreign language teaching, for example. It might be used, for instance, to promote professional development in Colombia. It plans to involve pre-service teachers initially and in-service ones later. The kind of interaction promoted by trainee teachers shows a very restricted possibility for young learners to use the language meaningfully in the classroom. Four stages are defined and suggested as a path to follow with pre-service teachers at Universidad Pedagógica y Tecnológica de Colombia –UPTC– in the Foreign Language Programme - FLP.

  9. Honeybee locomotion is impaired by Am-CaV3 low voltage-activated Ca(2+) channel antagonist.

    Science.gov (United States)

    Rousset, M; Collet, C; Cens, T; Bastin, F; Raymond, V; Massou, I; Menard, C; Thibaud, J-B; Charreton, M; Vignes, M; Chahine, M; Sandoz, J C; Charnet, P

    2017-02-01

    Voltage-gated Ca(2+) channels are key transducers of cellular excitability and participate in several crucial physiological responses. In vertebrates, 10 Ca(2+) channel genes, grouped in 3 families (CaV1, CaV2 and CaV3), have been described and characterized. Insects possess only one member of each family. These genes have been isolated in a limited number of species and very few have been characterized although, in addition to their crucial role, they may represent a collateral target for neurotoxic insecticides. We have isolated the 3 genes coding for the 3 Ca(2+) channels expressed in Apis mellifera. This work provides the first detailed characterization of the honeybee T-type CaV3 Ca(2+) channel and demonstrates the low toxicity of inhibiting this channel. Comparing Ca(2+) currents recorded in bee neurons and myocytes with Ca(2+) currents recorded in Xenopus oocytes expressing the honeybee CaV3 gene suggests native expression in bee muscle cells only. High-voltage activated Ca(2+) channels could be recorded in the somata of different cultured bee neurons. These functional data were confirmed by in situ hybridization, immunolocalization and in vivo analysis of the effects of a CaV3 inhibitor. The biophysical and pharmacological characterization and the tissue distribution of CaV3 suggest a role in honeybee muscle function.

  10. Honeybee locomotion is impaired by Am-CaV3 low voltage-activated Ca2+ channel antagonist

    Science.gov (United States)

    Rousset, M.; Collet, C.; Cens, T.; Bastin, F.; Raymond, V.; Massou, I.; Menard, C.; Thibaud, J.-B.; Charreton, M.; Vignes, M.; Chahine, M.; Sandoz, J. C.; Charnet, P.

    2017-01-01

    Voltage‐gated Ca2+ channels are key transducers of cellular excitability and participate in several crucial physiological responses. In vertebrates, 10 Ca2+ channel genes, grouped in 3 families (CaV1, CaV2 and CaV3), have been described and characterized. Insects possess only one member of each family. These genes have been isolated in a limited number of species and very few have been characterized although, in addition to their crucial role, they may represent a collateral target for neurotoxic insecticides. We have isolated the 3 genes coding for the 3 Ca2+ channels expressed in Apis mellifera. This work provides the first detailed characterization of the honeybee T-type CaV3 Ca2+ channel and demonstrates the low toxicity of inhibiting this channel. Comparing Ca2+ currents recorded in bee neurons and myocytes with Ca2+ currents recorded in Xenopus oocytes expressing the honeybee CaV3 gene suggests native expression in bee muscle cells only. High‐voltage activated Ca2+ channels could be recorded in the somata of different cultured bee neurons. These functional data were confirmed by in situ hybridization, immunolocalization and in vivo analysis of the effects of a CaV3 inhibitor. The biophysical and pharmacological characterization and the tissue distribution of CaV3 suggest a role in honeybee muscle function. PMID:28145504

  11. Determination of the membrane topology of the small EF-hand Ca2+-sensing proteins CaBP7 and CaBP8.

    Directory of Open Access Journals (Sweden)

    Hannah V McCue

    Full Text Available The CaBPs represent a subfamily of small EF-hand containing calcium (Ca(2+-sensing proteins related to calmodulin that regulate key ion channels in the mammalian nervous system. In a recent bioinformatic analyses we determined that CaBP7 and CaBP8 form an evolutionarily distinct branch within the CaBPs (also known as the calneurons a finding that is consistent with earlier observations characterising a putative C-terminal transmembrane (TM spanning helix in each of these proteins which is essential for their sub-cellular targeting to the Golgi apparatus and constitutive secretory vesicles. The C-terminal position of the predicted TM-helix suggests that CaBP7 and CaBP8 could be processed in a manner analogous to tail-anchored integral membrane proteins which exhibit the ability to insert across membranes post-translationally. In this study we have investigated the topology of CaBP7 and CaBP8 within cellular membranes through a combination of trypsin protection and epitope accessibility analyses. Our results indicate that the TM-helices of CaBP7 and CaBP8 insert fully across membranes such that their extreme C-termini are luminal. The observed type-II membrane topology is consistent with processing of CaBP7 and CaBP8 as true tail-anchored proteins. This targeting mechanism is distinct from any other calmodulin related Ca(2+-sensor and conceivably underpins unique physiological functions of these proteins.

  12. Positive magnetoresistance in Ca-doped cobaltites

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, S. M., E-mail: zhousm@ustc.edu.cn; Li, Y.; Guo, Y. Q.; Zhao, J. Y.; Shi, L., E-mail: shil@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-12-08

    Transport properties of polycrystalline La{sub 1−x}Ca{sub x}CoO{sub 3} (0.10 ≤ x ≤ 0.25) are systemically studied in this work. Three types of magnetoresistance (MR) effects are found in the Ca-doped cobaltites. Two negative MRs appear around high-temperature ferromagnetic transition and at low temperatures, which correspond to the conventional MR due to the field-induced suppression of spin-disorder scattering and the intergranular giant-MR due to spin-dependent transport between the ferromagnetic clusters, respectively. More interestingly, another exotic positive MR emerges at intermediate temperature region, which had not been previously reported in Sr- and Ba-doped cobaltites. It is found that this positive MR is associated with an abnormally magnetic transition and increases with the increase of x. For x = 0.25, the MR at low temperatures is dominated by the positive one, which is isotropic and nearly linear with the magnetic field. The possible origin of the positive MR in the Ca-doped cobaltites is discussed.

  13. de caña CAMECO

    Directory of Open Access Journals (Sweden)

    Carlos Suárez Ponciano

    2006-01-01

    Full Text Available El aumento de la producción de caña en Cuba se ha vuelto más que un objetivo una necesidad, es por ello que se introducen nuevas máquinas que den respuesta a esta situación. Teniendo esto como premisa y considerando la importancia que el cultivo de la caña tiene para el país es que se ha escogido el Complejo Agroindustrial (CAI «Héctor Molina Riaño» por la influencia que tiene, en la provincia La Habana, en los resultados de este cultivo para analizar el producto de los medios que intervienen en la cosecha y transporte de la caña de azúcar, así como las condiciones de explotación en que se desarrollan, lo cual constituye el objetivo de este trabajo. Se desarrolló una base metodológica para el análisis de los resultados.

  14. Superconductivity in Ca-doped graphene laminates

    Science.gov (United States)

    Chapman, J.; Su, Y.; Howard, C. A.; Kundys, D.; Grigorenko, A. N.; Guinea, F.; Geim, A. K.; Grigorieva, I. V.; Nair, R. R.

    2016-03-01

    Despite graphene’s long list of exceptional electronic properties and many theoretical predictions regarding the possibility of superconductivity in graphene, its direct and unambiguous experimental observation has not been achieved. We searched for superconductivity in weakly interacting, metal decorated graphene crystals assembled into so-called graphene laminates, consisting of well separated and electronically decoupled graphene crystallites. We report robust superconductivity in all Ca-doped graphene laminates. They become superconducting at temperatures (Tc) between ≈4 and ≈6 K, with Tc’s strongly dependent on the confinement of the Ca layer and the induced charge carrier concentration in graphene. We find that Ca is the only dopant that induces superconductivity in graphene laminates above 1.8 K among several dopants used in our experiments, such as potassium, caesium and lithium. By revealing the tunability of the superconducting response through doping and confinement of the metal layer, our work shows that achieving superconductivity in free-standing, metal decorated monolayer graphene is conditional on an optimum confinement of the metal layer and sufficient doping, thereby bringing its experimental realization within grasp.

  15. Superconductivity in Ca-doped graphene laminates

    Science.gov (United States)

    Chapman, J.; Su, Y.; Howard, C. A.; Kundys, D.; Grigorenko, A. N.; Guinea, F.; Geim, A. K.; Grigorieva, I. V.; Nair, R. R.

    2016-01-01

    Despite graphene’s long list of exceptional electronic properties and many theoretical predictions regarding the possibility of superconductivity in graphene, its direct and unambiguous experimental observation has not been achieved. We searched for superconductivity in weakly interacting, metal decorated graphene crystals assembled into so-called graphene laminates, consisting of well separated and electronically decoupled graphene crystallites. We report robust superconductivity in all Ca-doped graphene laminates. They become superconducting at temperatures (Tc) between ≈4 and ≈6 K, with Tc’s strongly dependent on the confinement of the Ca layer and the induced charge carrier concentration in graphene. We find that Ca is the only dopant that induces superconductivity in graphene laminates above 1.8 K among several dopants used in our experiments, such as potassium, caesium and lithium. By revealing the tunability of the superconducting response through doping and confinement of the metal layer, our work shows that achieving superconductivity in free-standing, metal decorated monolayer graphene is conditional on an optimum confinement of the metal layer and sufficient doping, thereby bringing its experimental realization within grasp. PMID:26979564

  16. Superconductivity in Ca-doped graphene laminates.

    Science.gov (United States)

    Chapman, J; Su, Y; Howard, C A; Kundys, D; Grigorenko, A N; Guinea, F; Geim, A K; Grigorieva, I V; Nair, R R

    2016-03-16

    Despite graphene's long list of exceptional electronic properties and many theoretical predictions regarding the possibility of superconductivity in graphene, its direct and unambiguous experimental observation has not been achieved. We searched for superconductivity in weakly interacting, metal decorated graphene crystals assembled into so-called graphene laminates, consisting of well separated and electronically decoupled graphene crystallites. We report robust superconductivity in all Ca-doped graphene laminates. They become superconducting at temperatures (Tc) between ≈4 and ≈6 K, with Tc's strongly dependent on the confinement of the Ca layer and the induced charge carrier concentration in graphene. We find that Ca is the only dopant that induces superconductivity in graphene laminates above 1.8 K among several dopants used in our experiments, such as potassium, caesium and lithium. By revealing the tunability of the superconducting response through doping and confinement of the metal layer, our work shows that achieving superconductivity in free-standing, metal decorated monolayer graphene is conditional on an optimum confinement of the metal layer and sufficient doping, thereby bringing its experimental realization within grasp.

  17. Arabidopsis transcriptional response to extracellular Ca2þ depletion involves a transient rise in cytosolic Ca

    Institute of Scientific and Technical Information of China (English)

    Zhi Qi

    2015-01-01

    Ecological evidence indicates a worldwide trend of dramatical y decreased soil Ca2þ levels caused by increased acid deposition and massive timber harvesting. Little is known about the genetic and cel ular mechanism of plants’ responses to Ca2þ depletion. In this study, transcriptional profiling analysis helped identify multiple extracel ular Ca2þ ([Ca2þ]ext) depletion‐respon-sive genes in Arabidopsis thaliana L., many of which are involved in response to other environmental stresses. Interestingly, a group of genes encoding putative cytosolic Ca2þ ([Ca2þ]cyt) sensors were significantly upregulated, implying that [Ca2þ]cyt has a role in sensing [Ca2þ]ext depletion. Consistent with this observation, [Ca2þ]ext depletion stimulated a transient rise in [Ca2þ]cyt that was negatively influenced by [Kþ]ext, suggesting the involvement of a membrane potential‐sensitive component. The [Ca2þ]cyt response to [Ca2þ]ext depletion was significantly desensitized after the initial treatment, which is typical of a receptor‐mediated signaling event. The response was insensi-tive to an animal Ca2þ sensor antagonist, but was suppressed by neomycin, an inhibitor of phospholipase C. Gd3þ, an inhibitor of Ca2þ channels, suppressed the [Ca2þ]ext‐triggered rise in [Ca2þ]cyt and downstream changes in gene expression. Taken together, this study demonstrates that [Ca2þ]cyt plays an important role in the putative receptor‐mediated cel ular and transcriptional response to [Ca2þ]ext depletion of plant cel s.

  18. Apamin Boosting of Synaptic Potentials in CaV2.3 R-Type Ca2+ Channel Null Mice.

    Science.gov (United States)

    Wang, Kang; Kelley, Melissa H; Wu, Wendy W; Adelman, John P; Maylie, James

    2015-01-01

    SK2- and KV4.2-containing K+ channels modulate evoked synaptic potentials in CA1 pyramidal neurons. Each is coupled to a distinct Ca2+ source that provides Ca2+-dependent feedback regulation to limit AMPA receptor (AMPAR)- and NMDA receptor (NMDAR)-mediated postsynaptic depolarization. SK2-containing channels are activated by Ca2+ entry through NMDARs, whereas KV4.2-containing channel availability is increased by Ca2+ entry through SNX-482 (SNX) sensitive CaV2.3 R-type Ca2+ channels. Recent studies have challenged the functional coupling between NMDARs and SK2-containing channels, suggesting that synaptic SK2-containing channels are instead activated by Ca2+ entry through R-type Ca2+ channels. Furthermore, SNX has been implicated to have off target affects, which would challenge the proposed coupling between R-type Ca2+ channels and KV4.2-containing K+ channels. To reconcile these conflicting results, we evaluated the effect of SK channel blocker apamin and R-type Ca2+ channel blocker SNX on evoked excitatory postsynaptic potentials (EPSPs) in CA1 pyramidal neurons from CaV2.3 null mice. The results show that in the absence of CaV2.3 channels, apamin application still boosted EPSPs. The boosting effect of CaV2.3 channel blockers on EPSPs observed in neurons from wild type mice was not observed in neurons from CaV2.3 null mice. These data are consistent with a model in which SK2-containing channels are functionally coupled to NMDARs and KV4.2-containing channels to CaV2.3 channels to provide negative feedback regulation of EPSPs in the spines of CA1 pyramidal neurons.

  19. Differential Ca2+ influx, KCa channel activity, and Ca2+ clearance distinguish Th1 and Th2 lymphocytes.

    Science.gov (United States)

    Fanger, C M; Neben, A L; Cahalan, M D

    2000-02-01

    In Th1 and Th2 lymphocytes, activation begins with identical stimuli but results in the production of different cytokines. The expression of some cytokine genes is differentially induced according to the amplitude and pattern of Ca2+ signaling. Using fura- 2 Ca2+ imaging of murine Th1 and Th2 clones, we observed that the Ca2+ rise elicited following store depletion with thapsigargin is significantly lower in Th2 cells than in Th1 cells. Maximal Ca2+ influx rates and whole-cell Ca2+ currents showed that both Th1 and Th2 cells express indistinguishable Ca2+-release-activated Ca2+ channels. Therefore, we investigated other mechanisms controlling the concentration of intracellular Ca2+, including K+ channels and Ca2+ clearance from the cytosol. Whole-cell recording demonstrated that there is no distinction in the amplitudes of voltage-gated K+ currents in the two cell types. Ca2+-activated K+ (KCa) currents, however, were significantly smaller in Th2 cells than in Th1 cells. Pharmacological equalization of Ca2+-activated K+ currents in the two cell types reduced but did not completely eliminate the difference between Th1 and Th2 Ca2+ responses, suggesting divergence in an additional Ca2+ regulatory mechanism. Therefore, we analyzed Ca2+ clearance from the cytosol of both cell types and found that Th2 cells extrude Ca2+ more quickly than Th1 cells. The combination of a faster Ca2+ clearance mechanism and smaller Ca2+-activated K+ currents in Th2 cells accounts for the lower Ca2+ response of Th2 cells compared with Th1 cells.

  20. The investigation on sulfation of modified Ca-based sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Hongwei Chen; Chunbo Wang; Yonghua Li; Zijie Wang [North China Electric Power University, Baoding (China). Department of Power Engineering

    2003-07-01

    The sulfation of a limestone modified by Na{sub 2}CO{sub 3} was investigated in this paper, which aimed to find the causes of its enhanced sulfation capacity. It was shown in the experiment that although the sulfur capture capability of M-CaO (the CaO calcined from modified limestone) is in excess of that of N-CaO (the CaO calcined from original sample), the specific surface area and porosity of the former are much less than that of the latter and also the average pore radius of the former become bigger. Based on the solid-state ion diffusion theory, a new mechanism to explain M-CaO sulfation is suggested. More lattice defects are formed in M-CaO, which reduce the resistance of ion diffusion in the CaSO{sub 4} product layer, and increase the Ca-conversion. To verify this, XRD was applied to measure the crystal structures of CaO samples. It was found M-CaO has bigger lattice distortion than N-CaO. It means that M-CaO has more lattice defects. In the sulfation the lattice defects in M-CaO will go into the CaSO{sub 4} product layer and it is that accelerates the ion diffusivity and leads to the higher Ca-conversion than that of N-CaO. By scanning the element distribution in reacted M-CaO using SEM, how the lattice defects formed in the product layers was verified.

  1. CaMKII in sinoatrial node physiology and dysfunction

    Directory of Open Access Journals (Sweden)

    Yuejin eWu

    2014-03-01

    Full Text Available The calcium and calmodulin dependent protein kinase II (CaMKII is present in sinoatrial node (SAN pacemaker cells and is required for physiological fight or flight SAN beating rate responses. Inhibition of CaMKII in SAN does not affect baseline heart rate, but reduces heart rate increases in response to physiological stress. CaMKII senses intracellular calcium (Ca2+ changes, oxidation status and hyperglycemia to phosphorylate substrates that regulate Ca2+-sensitive proteins, such as L-type Ca2+ channels, phospholamban (PLN, and cardiac ryanodine receptors (RyR2. All of these substrates are involved in the SAN pacemaking mechanism. Excessive CaMKII activity, as occurs under pathological conditions such as heart failure, ischemia and diabetes, can promote intracellular Ca2+ overload and reactive oxygen species (ROS production. Oxidation of CaMKII (ox-CaMKII locks CaMKII into a constitutively active configuration that contributes to SAN cell apoptosis and fibrosis. This ox-CaMKII-mediated loss of functional SAN cells contributes to sinoatrial node dysfunction (SND and sudden death. Thus, CaMKII has emerged as a central regulator of physiological SAN responses and a key determinant of SND.

  2. The emerging role of CaMKII in cancer.

    Science.gov (United States)

    Wang, Yan-yang; Zhao, Ren; Zhe, Hong

    2015-05-20

    Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a multifunctional serine/threonine kinases best known for its critical role in learning and memory. Recent studies suggested that high levels of CaMKII also expressed in variety of malignant diseases. In this review, we focus on the structure and biology properties of CaMKII, including the role of CaMKII in the regulation of cancer progression and therapy response. We also describe the role of CaMKII in the diagnosis of different kinds of cancer and recent progress in the development of CaMKII inhibitors. These data establishes CaMKII as a novel target whose modulation presents new opportunities for cancer diagnosis and treatment.

  3. Is tissue CA125 expression in epithelial ovarian adenocarcinoma heterogenic?

    DEFF Research Database (Denmark)

    Sparholt, Morten H; Høgdall, Claus K; Nedergaard, Lotte

    2013-01-01

    To evaluate if heterogeneity of tissue cancer antigen 125 (CA125) expression is present in epithelial serous adenocarcinomas. Furthermore, to investigate whether there is a correlation between levels of CA125 tissue expression, serum level of CA125, stage, and grade. A total of 10 patients...... diagnosed with serous ovarian adenocarcinomas were included. Preoperative blood samples were collected to determine serum CA125 levels. Tumor tissue from primary surgery was collected and processed for immunohistochemical analyses. CA125 was expressed in varying degrees in tumor tissues from all patients....... Mean tissue CA125 expression for each patient ranged from 36% to 98%. Intrapatient variations in tissue expression ranged from 10% to 90% point. No significant correlations between levels of CA125 tissue expression, serum level of CA125, stage, and grade were found. We found that the tissue expression...

  4. Pressure-induced structural transformation of CaC2

    Science.gov (United States)

    Wang, Lu; Huang, Xiaoli; Li, Da; Huang, Yanping; Bao, Kuo; Li, Fangfei; Wu, Gang; Liu, Bingbing; Cui, Tian

    2016-05-01

    The high pressure structural changes of calcium carbide CaC2 have been investigated with Raman spectroscopy and synchrotron X-ray diffraction (XRD) techniques in a diamond anvil cell at room temperature. At ambient conditions, two forms of CaC2 co-exist. Above 4.9 GPa, monoclinic CaC2-ii diminished indicating the structural phase transition from CaC2-ii to CaC2-i. At about 7.0 GPa, both XRD patterns and Raman spectra confirmed that CaC2-i transforms into a metallic Cmcm structure which contains polymeric carbon chains. Along with the phase transition, the isolated C2 dumbbells are polymerized into zigzag chains resulting in a large volume collapse with 22.4%. Above 30.0 GPa, the XRD patterns of CaC2 become featureless and remain featureless upon decompression, suggesting an irreversible amorphization of CaC2.

  5. A study of the ground states of CaC2H+2,CaC2D+2 and CaC2H+4

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The geometries, vibrational frequencies and bind energies are reported for the ground states of CaC2H+2, CaC2D+2 and CaC2H+4. CaC2H+2 and CaC2H+4 equilibrium geometries have C2v symmetry with the metal ion lying in the perpendicular bisector of the C-C bond. The ground state in both CaC2H+2 and CaC2H+4 molecules ia a 2A1 state and the binding in the ground state is mainly electrostatic. For both CaC2H+2 and CaC2H+4 the ligand is only slightly distorted from its free ligand structure, the C-C distance has hardly increased and there is only a very small bending of the H atom away from the Ca atom. This is consistent with the electrostatic nature of the bonding. Two different approaches-Hartree-Fock(HF) and density functional theory methods(DFT)-are used and basis sets here used is 6-311+G(3df,2p). The DFT results are in good agreement with experiments, namely, DFT methods provide the benefits that some more expensive ab initio methods can do, but at essentially HF cost. So it is important to include electron correlation for accurate results in this study.

  6. Measurement of mitochondrial Ca2+ transport mediated by three transport proteins: VDAC1, the Na+/Ca2+ exchanger, and the Ca2+ uniporter.

    Science.gov (United States)

    Ben-Hail, Danya; Palty, Raz; Shoshan-Barmatz, Varda

    2014-02-01

    Ca(2+) is a ubiquitous cellular signal, with changes in intracellular Ca(2+) concentration not only stimulating a number of intercellular events but also triggering cell death pathways, including apoptosis. Mitochondrial Ca(2+) uptake and release play pivotal roles in cellular physiology by regulating intracellular Ca(2+) signaling, energy metabolism and cell death. Ca(2+) transport across the inner and outer mitochondrial membranes is mediated by several proteins, including channels, antiporters, and a uniporter. In this article, we present the background to several methods now established for assaying mitochondrial Ca(2+) transport activity across both mitochondrial membranes. The first of these is Ca(2+) transport mediated by the outer mitochondrial protein, the voltage-dependent anion-selective channel protein 1 (VDAC1, also known as porin 1), both as a purified protein reconstituted into a planar lipid bilayer (PLB) or into liposomes and as a mitochondrial membrane-embedded protein. The second method involves isolated mitochondria for assaying the activity of an inner mitochondrial membrane transport protein, the mitochondrial Ca(2+) uniporter (MCU) that transports Ca(2+) and is powered by the steep mitochondrial membrane potential. In the event of Ca(2+) overload, this leads to opening of the mitochondrial permeability transition pore (MPTP) and cell death. The third method describes how Na(+)-dependent mitochondrial Ca(2+) efflux mediated by mitochondrial NCLX, a member of the Na(+)/Ca(2+) exchanger superfamily, can be assayed in digitonin-permeabilized HEK-293 cells. The Ca(2+)-transport assays can be performed under various conditions and in combination with inhibitors, allowing detailed characterization of the transport activity of interest.

  7. Serum concentrations of the biomarkers CA125, CA15-3, CA72-4, tPSA and PAPP-A in natural and stimulated ovarian cycles

    Institute of Scientific and Technical Information of China (English)

    Melissa Stemp; Peter Roberts; Allison McClements; Vincent Chapple; Jay Natalwala; Michael Black; Phillip Matson

    2014-01-01

    Objective:Biomarkers associated with cancer screening (CA125, CA15‐3, CA72‐4, total prostate specific antigen [tPSA]) and the monitoring of pregnancy (pregnancy associated plasma protein‐A [PAPP‐A]) were measured during natural and stimulated ovarian cycles in disease‐free non-pregnant women to determine if they could reflect normal events relating to ovulation and/or endometrial changes. Methods: A total of 73 blood samples (10 women) collected throughout the natural menstrual cycle, and 64 blood samples (11 women) taken during stimulated ovarian cycles, were analysed on the Roche Cobas e411 automated analyser. Results:Detectable levels of tPSA were measured in at least one point in the cycle in 6/10 of women in the natural cycle and 10/11 of women in stimulated cycles, and CA72-4 was detected in only 12/21 women tested. Concentrations of CA125, tPSA, CA15‐3 and CA72‐4 showed no significant difference between the natural and stimulated ovarian cycle groups. On average the mean PAPP‐A of the natural group was (2.41±0.58) mIU/L higher than the stimulated group (t=4.10, P< 0.001). CA125 and CA15‐3 results were both significantly influenced by the stage of the cycle (P<0.0001), whereas tPSA and PAPP‐A concentrations revealed no significant changes (P≥0.65). CA72‐4 was not affected by the stage of the cycle nor ovarian stimulation. Conclusion:Ovarian stimulation reduced serum PAPP‐A levels, CA125 and CA15‐3 levels were generally unaffected by ovarian stimulation but displayed cyclical changes throughout both natural and stimulated cycles, whilst tPSA and CA72-4 were not affected by the stage of the cycle or ovarian stimulation.

  8. Sr/Ca and Ba/Ca variations in environmental and biological sources: A survey of marine and terrestrial systems

    Science.gov (United States)

    Peek, Stephanie; Clementz, Mark T.

    2012-10-01

    The relative concentrations of strontium to calcium (Sr/Ca) and barium to calcium (Ba/Ca) in mammalian bioapatite are common biogeochemical indicators for trophic level and/or dietary preferences in terrestrial foodwebs; however, similar research in marine foodwebs is lacking. This study combined environmental and biological Sr/Ca and Ba/Ca data from both terrestrial and marine settings from 62 published books, reports, and studies along with original data collected from 149 marine mammals (30 species) and 83 prey items (18 species) and found that variations in Sr/Ca and Ba/Ca ratios of biological and environmental samples are appreciably different in terrestrial and marine systems. In terrestrial systems, environmental sources account for most of the variations in Sr/Ca and Ba/Ca ratios. In contrast, environmental sources in marine systems (i.e., seawater) are comparatively invariant, meaning most of the variations in Sr/Ca and Ba/Ca ratios originate from biological processes. Marine consumers, particularly non-mammalian and mammalian vertebrates, show evidence of biopurification of Ca relative to Sr and Ba, similar to what is observed in terrestrial systems; however, unlike terrestrial systems, variations in Sr/Ca and Ba/Ca ratios of environmental sources are overprinted by bioaccumulation of Sr and Ba at the base of marine foodwebs. This demonstrates that in marine systems, spatial or temporal differences may have little to no effect on Sr/Ca and Ba/Ca ratios of marine vertebrates, making Sr/Ca, and to a lesser extent Ba/Ca, potentially useful global proxies for trophic level and dietary preferences of marine vertebrates.

  9. MicroRNA-145 suppresses ROS-induced Ca{sup 2+} overload of cardiomyocytes by targeting CaMKIIδ

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Min-Ji [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Jang, Jin-Kyung [College of Pharmacy, Sookmyung Women’s University, 52 HyoChangWon-Gil, Yongsan-ku, Seoul 140-742 (Korea, Republic of); Ham, Onju; Song, Byeong-Wook; Lee, Se-Yeon [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Lee, Chang Yeon; Park, Jun-Hee [Department of Integrated Omics for Biomedical Sciences, Graduate School, Yonsei University, 50 Yonsei-ro, Seodamun-gu, Seoul 120-759 (Korea, Republic of); Lee, Jiyun; Seo, Hyang-Hee [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Choi, Eunhyun [Severance Integrative Research Institute for Cerebral and Cardiovascular Disease, Yonsei University Health System, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Jeon, Woo-min [Department of Animal Resource, Sahmyook University, Seoul 139-742 (Korea, Republic of); Hwang, Hye Jin [Cardiovascular Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodamun-gu, Seoul 120-752 (Korea, Republic of); Shin, Hyun-Taek [College of Pharmacy, Sookmyung Women’s University, 52 HyoChangWon-Gil, Yongsan-ku, Seoul 140-742 (Korea, Republic of); and others

    2013-06-14

    Highlights: •CaMKIIδ mediates H{sub 2}O{sub 2}-induced Ca{sup 2+} overload in cardiomyocytes. •miR-145 can inhibit Ca{sup 2+} overload. •A luciferase assay confirms that miR-145 functions as a CaMKIIδ-targeting miRNA. •Overexpression of miR-145 regulates CaMKIIδ-related genes and ameliorates apoptosis. -- Abstract: A change in intracellular free calcium (Ca{sup 2+}) is a common signaling mechanism of reperfusion-induced cardiomyocyte death. Calcium/calmodulin dependent protein kinase II (CaMKII) is a critical regulator of Ca{sup 2+} signaling and mediates signaling pathways responsible for functions in the heart including hypertrophy, apoptosis, arrhythmia, and heart disease. MicroRNAs (miRNA) are involved in the regulation of cell response, including survival, proliferation, apoptosis, and development. However, the roles of miRNAs in Ca{sup 2+}-mediated apoptosis of cardiomyocytes are uncertain. Here, we determined the potential role of miRNA in the regulation of CaMKII dependent apoptosis and explored its underlying mechanism. To determine the potential roles of miRNAs in H{sub 2}O{sub 2}-mediated Ca{sup 2+} overload, we selected and tested 6 putative miRNAs that targeted CaMKIIδ, and showed that miR-145 represses CaMKIIδ protein expression and Ca{sup 2+} overload. We confirmed CaMKIIδ as a direct downstream target of miR-145. Furthermore, miR-145 regulates Ca{sup 2+}-related signals and ameliorates apoptosis. This study demonstrates that miR-145 regulates reactive oxygen species (ROS)-induced Ca{sup 2+} overload in cardiomyocytes. Thus, miR-145 affects ROS-mediated gene regulation and cellular injury responses.

  10. Application of Ca stable isotopes to long-term changes in the Ca cycle of a Northern Hardwood forest

    Science.gov (United States)

    Kurtz, A. C.; Takagi, K.; Bailey, S. W.; Bullen, T. D.

    2015-12-01

    The Hubbard Brook Ecosystem Study (New Hampshire, USA) presents an unusual opportunity for the application of innovative isotope methods in forest biogeochemistry. Changes in biogeochemical cycling resulting from decades of acid deposition, subsequent reductions in acid deposition, and a series of experimental treatments (harvesting, Ca amendment) have been studied continuously for 60 years at this site. Importantly, researchers have archived soil, water, and vegetation samples for much of the site's history. Our work seeks to complement earlier mass balance studies of Ca cycling by measuring Ca isotope ratios on archived samples. In the first component of our study, we examined the Ca isotopic response to an experimental clearcut in the early 1980's. Earlier work showed that the clearcut promoted dramatic loss of Ca from the watershed, indicated by a 5-fold increase in streamwater Ca concentrations. The mechanism for this loss was unclear as no resolvable changes in soil Ca pools were observed. Our work shows that streamwater dissolved Ca becomes isotopically lighter as Ca concentrations increase. These data are best accounted for by an increase in Ca loss from the soil cation exchange complex. Soil exchangeable δ44Ca itself evolves towards lighter values in the years following the experimental harvest. We interpret this as replenishment of the soil exchange complex by release of isotopically light Ca from root biomass. In the second component of our study, we examine decadal-scale changes in streamwater and soil Ca in an un-manipulated biogeochemical reference watershed. Historical data from Hubbard Brook show that streamwater Ca concentrations began decreasing sharply in the early 1970's, attributed to decreased deposition of both acidity and Ca with the passage of the Clean Air Act. Preliminary data indicate no resolvable change in the average δ44Ca of streamwater, with variability mostly attributable to discharge (flowpath control). Preliminary data

  11. Reaction process of monazite and bastnaesite mixed rare earth minerals calcined by CaO-NaCl-CaCl2

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The decomposition reactions of monazite and bastnaesite mixed rare earth minerals calcined by CaO-NaCl-CaCl2 were studied by means of TG-DTA and XRD. The results show that the process of the minerals decomposed by CaO involves two steps.The first step occurs in the temperature range of 425-540 ℃, and the main reactions are bastnaesite decomposition, i.e. REOF reacts with CaO to produce RE2O3 and CaF2, and Ce2O3 is oxidized to CeO2. During this step, CaCO3 is formed at about 500 ℃. The second step takes place in the temperature range of 610-700 ℃, and the reactions are monazite decomposition into RE2O3,Ca5F(PO4)3 and Ca3(PO4)2 by CaO and CaF2. In this process, the decomposition ability is improved because CaO from CaCO3decomposing has high chemical activity. In calcining process, the new formed Ca5F(PO4)3 restrains fluorine that can escape in form of gaseous compound. The decomposition ratio of the mixed rare earth minerals reaches 90.8% at 700 ℃.

  12. Modeling CaMKII-mediated regulation of L-type Ca2+ channels and ryanodine receptors in the heart

    Directory of Open Access Journals (Sweden)

    Joseph L Greenstein

    2014-04-01

    Full Text Available Excitation-contraction coupling (ECC in the cardiac myocyte is mediated by a number of highly integrated mechanisms of intracellular Ca2+ transport. Voltage- and Ca2+-dependent L-type Ca2+ channels (LCCs allow for Ca2+ entry into the myocyte, which then binds to nearby ryanodine receptors (RyRs and triggers Ca2+ release from the sarcoplasmic reticulum in a process known as Ca2+-induced Ca2+ release. The highly coordinated Ca2+-mediated interaction between LCCs and RyRs is further regulated by the cardiac isoform of the Ca2+/calmodulin-dependent protein kinase (CaMKII. Because CaMKII targets and modulates the function of many ECC proteins, elucidation of its role in ECC and integrative cellular function is challenging and much insight has been gained through the use of detailed computational models. Multiscale models that can both reconstruct the detailed nature of local signaling events within the cardiac dyad and predict their functional consequences at the level of the whole cell have played an important role in advancing our understanding of CaMKII function in ECC. Here, we review experimentally based models of CaMKII function with a focus on LCC and RyR regulation, and the mechanistic insights that have been gained through their application.

  13. Mitochondrial free [Ca2+] levels and the permeability transition

    OpenAIRE

    Vay, Laura; Hernández-SanMiguel, Esther; Domínguez Lobatón, María Carmen; Moreno, Alfredo; Montero, Mayte; Álvarez, Javier

    2009-01-01

    Producción Científica Mitochondrial Ca2+ activates many processes, from mitochondrial metabolism to opening of the permeability transition pore (PTP) and apoptosis. However, there is considerable controversy regarding the free mitochondrial [Ca2+] ([Ca2+]M) levels that can be attained during cell activation or even in mitochondrial preparations. Studies using fluorescent dyes (rhod-2 or similar), have reported that phosphate precipitation precludes [Ca2+]M from increasing above...

  14. 血清CEA、CA-125、CA-153、CA-199、CA242联合检测对消化道肿瘤诊断的临床意义

    Institute of Scientific and Technical Information of China (English)

    杨德辉; 周力; 张永宏; 张澜林; 谭玉洁; 王焰; 秦雯

    2006-01-01

    目的:探讨血清CEA、CA-125、CA-153、CA-199、CA242联合检测对消化道肿瘤诊断的临床意义。方法:采用酶联免疫吸附法(ELISA法)检测130例恶性消化道肿瘤患者(食管癌32例、胃癌34例、胰腺癌30例、大肠癌34例)血清CEA、CA-125、CA-153、CA-199、CA242水平。结果:表明上述四种消化道肿瘤的血清CEA、CA-125、CA-153、CA-199、CA242与对照组比较结果统计学上均有显著性差异(P〈0.01)。除胰腺癌之外,其余3种消化道肿瘤五项肿瘤标记物联合检测的阳性率均显著高于单一标志物检测(P〈0.05),分别为食管癌62.5%、胃癌85.2%、大肠癌82.3%。结论:血清CEA、CA-125、CA-153、CA-199、CA242联合检测可以显著提高消化道恶性肿瘤诊断的敏感性。

  15. TRPV5, the gateway to Ca2+ homeostasis.

    NARCIS (Netherlands)

    Mensenkamp, A.R.; Hoenderop, J.G.J.; Bindels, R.J.M.

    2007-01-01

    Ca2+ homeostasis in the body is tightly controlled, and is a balance between absorption in the intestine, excretion via the urine, and exchange from bone. Recently, the epithelial Ca2+ channel (TRPV5) has been identified as the gene responsible for the Ca2+ influx in epithelial cells of the renal di

  16. Serum tetranectin and CA125 in endometrial adenocarcinoma

    DEFF Research Database (Denmark)

    Lundstrøm, M S; Høgdall, C K; Nielsen, Anette Lynge;

    2000-01-01

    in relation to tumor grade, stage and cancer survival. RESULTS: The CA125 levels correlated significantly with tumor stage. Dichotomized according to a cut-off level of 35 U/ml, CA125 significantly correlated with cancer death. Multivariate regression analysis of cancer survival time showed that CA125 > 35 U/ml...

  17. 33 CFR 110.210 - San Diego Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false San Diego Harbor, CA. 110.210... ANCHORAGE REGULATIONS Anchorage Grounds § 110.210 San Diego Harbor, CA. (a) The anchorage grounds. (1... Commander, Naval Base, San Diego, CA. The administration of these anchorages is exercised by the...

  18. Distribution of Phosphorus between CaO-CaF2 Slag and Fe-C-P Melt

    Institute of Scientific and Technical Information of China (English)

    WANG Qing-xiang; ZHOU Jian-jian; DU Xiao-jian

    2005-01-01

    The equilibrium distribution ratio of phosphorus between CaO-CaF2 molten slag and Fe-C-P melt at 1450 ℃ was measured. The phosphate capacity of slag and the activity coefficient of phosphorus oxide were calculated.

  19. Solid state interactions in the systems CaO(CaCO3-Fe2O3 and CuFe2O4-CaO

    Directory of Open Access Journals (Sweden)

    Boyanov B.S.

    2005-01-01

    Full Text Available The solid state interactions in the systems CaO(CaCO3-Fe2O3 and CuFe2O4-CaO have been studied using X-ray diffraction analysis. The influence of the temperature on the ferrite formation process has been investigated in the range of 900-1200 oC and duration up to 360 min. It has been shown that a mixture of ferrites forms at 1000 oC and interaction of 240 min. The exchange reactions in the systems CuFe2O4-CaO and Cu0.5Zn0.5Fe2O4-CaO have been studied, too. It has been established that Ca2+ ions exchange Cu2+ and Zn2 partially and the solubility of copper and zinc in a 7 % sulfuric acid solution increases 10-15 times.

  20. The effect of CaF2 on thermodynamics of CaO-CaF2-SiO2(-MgO) slags

    Science.gov (United States)

    Choi, Chul-Hwan; Jo, Sung-Koo; Kim, Seon-Hyo; Lee, Kwang-Ro; Kim, Jeong-Tae

    2004-02-01

    To address the role of CaF2 in the CaO-CaF2-SiO2(-MgO) slag system employed for the production of low-pressure rotor steels, the thermodynamic aspects of the slag were investigated by equilibrating it with liquid iron at 1873 K in CaO or MgO crucibles. Presaturation of slag with an oxide block piece of CaO or MgO in a Pt crucible and application of a carbon paste to the outside of an oxide crucible were designed to prevent crucible failure during the slag-metal experiments. The liquidus isotherm and phase boundary of the preceding slag system were investigated using the slag-metal equilibria. Also, the effect of CaF2 on the sulfide capacity and the activity coefficient of Fe t O were of particular interest in controlling the sulfur level and cleanliness of low-pressure rotor steels.

  1. Citrus bergamia Risso Elevates Intracellular Ca2+ in Human Vascular Endothelial Cells due to Release of Ca2+ from Primary Intracellular Stores

    Directory of Open Access Journals (Sweden)

    Purum Kang

    2013-01-01

    , which was partially inhibited by a nonselective Ca2+ channel blocker La3+. In Ca2+-free extracellular solutions, BEO increased [Ca2+]i in a concentration-dependent manner, suggesting that BEO mobilizes intracellular Ca2+. BEO-induced [Ca2+]i increase was partially inhibited by a Ca2+-induced Ca2+ release inhibitor dantrolene, a phospholipase C inhibitor U73122, and an inositol 1,4,5-triphosphate (IP3-gated Ca2+ channel blocker, 2-aminoethoxydiphenyl borane (2-APB. BEO also increased [Ca2+]i in the presence of carbonyl cyanide m-chlorophenylhydrazone, an inhibitor of mitochondrial Ca2+ uptake. In addition, store-operated Ca2+ entry (SOC was potentiated by BEO. These results suggest that BEO mobilizes Ca2+ from primary intracellular stores via Ca2+-induced and IP3-mediated Ca2+ release and affect promotion of Ca2+ influx, likely via an SOC mechanism.

  2. Feedforward Inhibition Underlies the Propagation of Cholinergically Induced Gamma Oscillations from Hippocampal CA3 to CA1

    OpenAIRE

    Zemankovics, Rita; Veres, Judit M.; Oren, Iris; Hájos, Norbert

    2013-01-01

    Gamma frequency (30–80 Hz) oscillations are implicated in memory processing. Such rhythmic activity can be generated intrinsically in the CA3 region of the hippocampus from where it can propagate to the CA1 area. To uncover the synaptic mechanisms underlying the intrahippocampal spread of gamma oscillations, we recorded local field potentials, as well as action potentials and synaptic currents in anatomically identified CA1 and CA3 neurons during carbachol-induced gamma oscillations in mouse ...

  3. Reorientable dipolar CuCa antisite and anomalous screening in CaCu3Ti4O12

    Science.gov (United States)

    Delugas, Pietro; Alippi, Paola; Fiorentini, Vincenzo; Raineri, Vito

    2010-02-01

    Based on first-principles calculations, we show that the abundant CuCa antisite defect contributes sizably to dielectric screening in single-crystal CaCu3Ti4O12 . CuCa has a multi-minimum off-center equilibrium configuration, whereby it possesses a large and easily reorientable dipole moment. The low-temperature and frequency cut-off behavior of CuCa -induced response is consistent with experiment.

  4. Biological fractionation of stable Ca isotopes in Göttingen minipigs as a physiological model for Ca homeostasis in humans.

    Science.gov (United States)

    Heuser, Alexander; Eisenhauer, Anton; Scholz-Ahrens, Katharina E; Schrezenmeir, Jürgen

    2016-12-01

    In order to investigate fractionation of calcium (Ca) isotopes in vertebrates as a diagnostic tool to detect Ca metabolism dysfunction we analyzed the Ca isotopic composition (δ(44/40)Ca = [((44)Ca/(40)Ca)sample/((44)Ca/(40)Ca)reference]-1) of diet, faeces, blood, bones and urine from Göttingen minipigs, an animal model for human physiology. Samples of three groups were investigated: 1. control group (Con), 2. group with glucocorticosteroid induced osteoporosis (GIO) and 3. group with Ca and vitamin D deficiency induced osteomalacia (-CaD). In contrast to Con and GIO whose average δ(44/40)Cafaeces values (0.39 ± 0.13‰ and 0.28 ± 0.08‰, respectively) tend to be lower than their diet (0.47 ± 0.02‰), δ(44/40)Cafaeces of -CaD (-0.27 ± 0.21‰) was significantly lower than their δ(44/40)Cadiet (0.37 ± 0.03‰), but also lower than δ(44/40)Cafaeces of Con and GIO. We suggest that the low δ(44/40)Cafaeces of -CaD might be due to the contribution of isotopically light Ca from gastrointestinal fluids during gut passage. Assuming that this endogenous Ca source is a common physiologic feature, a fractionation during Ca absorption is also required for explaining δ(44/40)Cafaeces of Con and GIO. The δ(44/40)Caurine of all groups are high (>2.0‰) reflecting preferential renal reabsorption of light Ca isotopes. In Göttingen minipigs we found a Ca isotope fractionation between blood and bones (Δ(44/40)Cablood-bone) of 0.68 ± 0.15‰.

  5. Calbindin-D28K dynamically controls TRPV5-mediated Ca2+ transport.

    NARCIS (Netherlands)

    Lambers, T.T.; Mahieu, F.; Oancea, E.; Hoofd, L.J.C.; Lange, F. de; Mensenkamp, A.R.; Voets, T.; Nilius, B.; Clapham, D.E.; Hoenderop, J.G.J.; Bindels, R.J.M.

    2006-01-01

    In Ca(2+)-transporting epithelia, calbindin-D(28K) (CaBP(28K)) facilitates Ca(2+) diffusion from the luminal Ca(2+) entry side of the cell to the basolateral side, where Ca(2+) is extruded into the extracellular compartment. Simultaneously, CaBP(28K) provides protection against toxic high Ca(2+) lev

  6. Ultrastructural and immunohistochemical localization of plasma membrane Ca2+-ATPase 4 in Ca2+-transporting epithelia

    DEFF Research Database (Denmark)

    Alexander, R Todd; Beggs, Megan R; Zamani, Reza;

    2015-01-01

    role in transcellular Ca(2+) flux and investigated the localization and regulation of Pmca4 in Ca(2+)-transporting epithelia. Using antibodies directed specifically against Pmca4, we found it expressed only in the smooth muscle layer of mouse and human intestine, while pan-specific Pmca antibodies...... the cortical thick ascending limbs, macula densa, and early distal tubules as well as smooth muscle layers surrounding renal vessels. In human kidney, a similar pattern of distribution was observed, with highest PMCA4 expression in NCC positive tubules. Electron microscopy demonstrated Pmca4 localization...... in distal nephron cells at both the basolateral membrane and intracellular perinuclear compartments, but not submembranous vesicles, suggesting rapid trafficking to the plasma membrane is unlikely to occur in vivo. Pmca4 expression was not altered by perturbations in Ca(2+) balance, pointing...

  7. An ID-like current that is downregulated by Ca2+ modulates information coding at CA3-CA3 synapses in the rat hippocampus.

    Science.gov (United States)

    Saviane, Chiara; Mohajerani, Majid H; Cherubini, Enrico

    2003-10-15

    Voltage-gated K+ channels localised on presynaptic nerve terminals control information coding by modulating presynaptic firing and synaptic efficacy in target neurones. We found that at CA3-CA3 connections in hippocampal slice cultures, a fast-activating, slowly inactivating K+ conductance similar to the so-called delay current (ID) is responsible for the delayed appearance of the first spike upon membrane depolarisation, for action potential repolarisation and for modulation of transmitter release. The ID-like current was downregulated by intracellular Ca2+, as indicated by the increased delay in the appearance of the first action potential following either the block of Ca2+ flux through voltage-dependent Ca2+ channels with Cd2+ or replacement of the bathing solution with one devoid of Ca2+. In both cases, this effect was reversed by blocking this conductance with a low concentration of 4-aminopyridine (4-AP, 10-50 muM). Application of 4-AP shortened the delay to the first spike generation, prevented the effect of Cd2+ and increased the spike duration. The earlier appearance of the first action potential was also observed in the presence of dendrotoxin-1 (100 nM). In voltage-clamp experiments larger currents were recorded in the absence of extracellular Ca2+, thus confirming the downregulation of the ID-like current by Ca2+ due to the positive shift of its inactivation. Spike broadening was associated with an enhancement of synaptic efficacy in target neurones, as assessed by the increase in EPSC amplitude and in the percentage of successes. Moreover, in the presence of 4-AP, EPSCs appeared with a longer latency and were more scattered. This conductance is therefore crucial for setting the timing and strength of synaptic transmission at CA3-CA3 connections. It is conceivable that switching off ID by increasing intracellular Ca2+ following activity-dependent processes may facilitate network synchronisation and crosstalk between CA3 pyramidal cells, leading to

  8. The other side of cardiac Ca2+ signaling: transcriptional control

    Directory of Open Access Journals (Sweden)

    Alejandro eDomínguez-Rodríquez

    2012-11-01

    Full Text Available Ca2+ is probably the most versatile signal transduction element used by all cell types. In the heart, it is essential to activate cellular contraction in each heartbeat. Nevertheless Ca2+ is not only a key element in excitation-contraction coupling (EC coupling, but it is also a pivotal second messenger in cardiac signal transduction, being able to control processes such as excitability, metabolism, and transcriptional regulation. Regarding the latter, Ca2+ activates Ca2+-dependent transcription factors by a process called excitation-transcription coupling (ET coupling. ET coupling is an integrated process by which the common signaling pathways that regulate EC coupling activate transcription factors. Although ET coupling has been extensively studied in neurons and other cell types, less is known in cardiac muscle. Some hints have been found in studies on the development of cardiac hypertrophy, where two Ca2+-dependent enzymes are key actors: Ca2+/Calmodulin kinase II (CaMKII and phosphatase calcineurin, both of which are activated by the complex Ca2+/ /Calmodulin. The question now is how ET coupling occurs in cardiomyocytes, where intracellular Ca2+ is continuously oscillating. In this focused review, we will draw attention to location of Ca2+ signaling: intranuclear ([Ca2+]n or cytoplasmic ([Ca2+]c, and the specific ionic channels involved in the activation of cardiac ET coupling. Specifically, we will highlight the role of the 1,4,5 inositol triphosphate receptors (IP3Rs in the elevation of [Ca2+]n levels, which are important to locally activate CaMKII, and the role of transient receptor potential channels canonical (TRPCs in [Ca2+]c, needed to activate calcineurin.

  9. Chloroquine Inhibits Ca2+ Signaling in Murine CD4+ Thymocytes

    Directory of Open Access Journals (Sweden)

    Jin-Chao Xu

    2015-04-01

    Full Text Available Background/Aims: Bitter-tasting chloroquine can suppress T cell activation by inhibiting Ca2+ signaling. However, the mechanism of inhibition remains largely unclear. Methods: In this study, CD4+ T cells were isolated from the thymus, and the calcium content of CD4+ thymocytes was measured using fura-2 AM and a TILL imaging system. Pyrazole-3 (Pyr3, thapsigargin (TG, and caffeine were used to assess the effects of chloroquine on the intracellular Ca2+ content of CD4+ T cells. Results: In murine CD4+ thymocytes, chloroquine decreased the TG-triggered intracellular Ca2+ increase in a dose-dependent manner. In the absence of chloroquine under Ca2+-free conditions (0 mM Ca2+ and 0.5 mM EGTA, TG induced a transient Ca2+ increase. After restoration of the extracellular Ca2+ concentration to 2 mM, a dramatic Ca2+ increase occurred. This elevation was completely blocked by chloroquine and was markedly inhibited by Pyr3, a selective antagonist of transient receptor potential C3 (TRPC3 channel and stromal interaction molecule (STIM/Orai channel. Furthermore, the TG-induced transient Ca2+ increase under Ca2+-free conditions was eliminated in the presence of chloroquine. Chloroquine also blocked the dialyzed inositol-1,4,5-trisphosphate (IP3-induced intracellular Ca2+ increase. However, chloroquine was not able to decrease the caffeine-induced Ca2+ increase. Conclusion: These data indicate that chloroquine inhibits the elevation of intracellular Ca2+ in thymic CD4+ T cells by inhibiting IP3 receptor-mediated Ca2+ release from intracellular stores and TRPC3 channel-mediated and/or STIM/Orai channel-mediated Ca2+ influx.

  10. Ca2+-Regulated Photoproteins: Effective Immunoassay Reporters

    Directory of Open Access Journals (Sweden)

    Ludmila A. Frank

    2010-12-01

    Full Text Available Ca2+-regulated photoproteins of luminous marine coelenterates are of interest and a challenge for researchers as a unique bioluminescent system and as a promising analytical instrument for both in vivo and in vitro applications. The proteins are comprehensively studied as to biochemical properties, tertiary structures, bioluminescence mechanism, etc. This knowledge, along with available recombinant proteins serves the basis for development of unique bioluminescent detection systems that are “self-contained”, triggerable, fast, highly sensitive, and non-hazardous. In the paper, we focus on the use of photoproteins as reporters in binding assays based on immunological recognition element—bioluminescent immunoassay and hybridization immunoassay, their advantages and prospects.

  11. Superdeformed and Triaxial States in ^{42}Ca.

    Science.gov (United States)

    Hadyńska-Klȩk, K; Napiorkowski, P J; Zielińska, M; Srebrny, J; Maj, A; Azaiez, F; Valiente Dobón, J J; Kicińska-Habior, M; Nowacki, F; Naïdja, H; Bounthong, B; Rodríguez, T R; de Angelis, G; Abraham, T; Anil Kumar, G; Bazzacco, D; Bellato, M; Bortolato, D; Bednarczyk, P; Benzoni, G; Berti, L; Birkenbach, B; Bruyneel, B; Brambilla, S; Camera, F; Chavas, J; Cederwall, B; Charles, L; Ciemała, M; Cocconi, P; Coleman-Smith, P; Colombo, A; Corsi, A; Crespi, F C L; Cullen, D M; Czermak, A; Désesquelles, P; Doherty, D T; Dulny, B; Eberth, J; Farnea, E; Fornal, B; Franchoo, S; Gadea, A; Giaz, A; Gottardo, A; Grave, X; Grȩbosz, J; Görgen, A; Gulmini, M; Habermann, T; Hess, H; Isocrate, R; Iwanicki, J; Jaworski, G; Judson, D S; Jungclaus, A; Karkour, N; Kmiecik, M; Karpiński, D; Kisieliński, M; Kondratyev, N; Korichi, A; Komorowska, M; Kowalczyk, M; Korten, W; Krzysiek, M; Lehaut, G; Leoni, S; Ljungvall, J; Lopez-Martens, A; Lunardi, S; Maron, G; Mazurek, K; Menegazzo, R; Mengoni, D; Merchán, E; Mȩczyński, W; Michelagnoli, C; Mierzejewski, J; Million, B; Myalski, S; Napoli, D R; Nicolini, R; Niikura, M; Obertelli, A; Özmen, S F; Palacz, M; Próchniak, L; Pullia, A; Quintana, B; Rampazzo, G; Recchia, F; Redon, N; Reiter, P; Rosso, D; Rusek, K; Sahin, E; Salsac, M-D; Söderström, P-A; Stefan, I; Stézowski, O; Styczeń, J; Theisen, Ch; Toniolo, N; Ur, C A; Vandone, V; Wadsworth, R; Wasilewska, B; Wiens, A; Wood, J L; Wrzosek-Lipska, K; Ziȩbliński, M

    2016-08-01

    Shape parameters of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in ^{42}Ca were determined from E2 matrix elements measured in the first low-energy Coulomb excitation experiment performed with AGATA. The picture of two coexisting structures is well reproduced by new state-of-the-art large-scale shell model and beyond-mean-field calculations. Experimental evidence for superdeformation of the band built on 0_{2}^{+} has been obtained and the role of triaxiality in the A∼40 mass region is discussed. Furthermore, the potential of Coulomb excitation as a tool to study superdeformation has been demonstrated for the first time.

  12. 拯救老兵CA

    Institute of Scientific and Technical Information of China (English)

    威廉·麦克拉肯

    2011-01-01

    @@ 是的,CA Technologies(冠群电脑)还活着.这家由美籍华人王嘉廉创办的软件公司,曾经风光无限,甚至一度有比肩微软的可能.然而混乱的内部管理与频繁的决策失误,造成了公司业绩低迷,随即也引发了股东间的权力纷争.

  13. Mechanics of Old Faithful Geyser, Calistoga, CA

    Science.gov (United States)

    Rudolph, M.L.; Manga, M.; Hurwitz, Shaul; Johnston, Malcolm J.; Karlstrom, L.; Wang, Chun-Yong

    2012-01-01

    In order to probe the subsurface dynamics associated with geyser eruptions, we measured ground deformation at Old Faithful Geyser of Calistoga, CA. We present a physical model in which recharge during the period preceding an eruption is driven by pressure differences relative to the aquifer supplying the geyser. The model predicts that pressure and ground deformation are characterized by an exponential function of time, consistent with our observations. The geyser's conduit is connected to a reservoir at a depth of at least 42 m, and pressure changes in the reservoir can produce the observed ground deformations through either a poroelastic or elastic mechanical model.

  14. Superdeformed and Triaxial States in 42Ca

    Science.gov (United States)

    Hadyńska-KlÈ©k, K.; Napiorkowski, P. J.; Zielińska, M.; Srebrny, J.; Maj, A.; Azaiez, F.; Valiente Dobón, J. J.; Kicińska-Habior, M.; Nowacki, F.; Naïdja, H.; Bounthong, B.; Rodríguez, T. R.; de Angelis, G.; Abraham, T.; Anil Kumar, G.; Bazzacco, D.; Bellato, M.; Bortolato, D.; Bednarczyk, P.; Benzoni, G.; Berti, L.; Birkenbach, B.; Bruyneel, B.; Brambilla, S.; Camera, F.; Chavas, J.; Cederwall, B.; Charles, L.; Ciemała, M.; Cocconi, P.; Coleman-Smith, P.; Colombo, A.; Corsi, A.; Crespi, F. C. L.; Cullen, D. M.; Czermak, A.; Désesquelles, P.; Doherty, D. T.; Dulny, B.; Eberth, J.; Farnea, E.; Fornal, B.; Franchoo, S.; Gadea, A.; Giaz, A.; Gottardo, A.; Grave, X.; GrÈ©bosz, J.; Görgen, A.; Gulmini, M.; Habermann, T.; Hess, H.; Isocrate, R.; Iwanicki, J.; Jaworski, G.; Judson, D. S.; Jungclaus, A.; Karkour, N.; Kmiecik, M.; Karpiński, D.; Kisieliński, M.; Kondratyev, N.; Korichi, A.; Komorowska, M.; Kowalczyk, M.; Korten, W.; Krzysiek, M.; Lehaut, G.; Leoni, S.; Ljungvall, J.; Lopez-Martens, A.; Lunardi, S.; Maron, G.; Mazurek, K.; Menegazzo, R.; Mengoni, D.; Merchán, E.; MÈ©czyński, W.; Michelagnoli, C.; Mierzejewski, J.; Million, B.; Myalski, S.; Napoli, D. R.; Nicolini, R.; Niikura, M.; Obertelli, A.; Özmen, S. F.; Palacz, M.; Próchniak, L.; Pullia, A.; Quintana, B.; Rampazzo, G.; Recchia, F.; Redon, N.; Reiter, P.; Rosso, D.; Rusek, K.; Sahin, E.; Salsac, M.-D.; Söderström, P.-A.; Stefan, I.; Stézowski, O.; Styczeń, J.; Theisen, Ch.; Toniolo, N.; Ur, C. A.; Vandone, V.; Wadsworth, R.; Wasilewska, B.; Wiens, A.; Wood, J. L.; Wrzosek-Lipska, K.; ZiÈ©bliński, M.

    2016-08-01

    Shape parameters of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in 42Ca were determined from E 2 matrix elements measured in the first low-energy Coulomb excitation experiment performed with AGATA. The picture of two coexisting structures is well reproduced by new state-of-the-art large-scale shell model and beyond-mean-field calculations. Experimental evidence for superdeformation of the band built on 02+ has been obtained and the role of triaxiality in the A ˜40 mass region is discussed. Furthermore, the potential of Coulomb excitation as a tool to study superdeformation has been demonstrated for the first time.

  15. Ca(2+) homeostasis in the budding yeast Saccharomyces cerevisiae: Impact of ER/Golgi Ca(2+) storage.

    Science.gov (United States)

    D'hooge, Petra; Coun, Catherina; Van Eyck, Vincent; Faes, Liesbeth; Ghillebert, Ruben; Mariën, Lore; Winderickx, Joris; Callewaert, Geert

    2015-08-01

    Yeast has proven to be a powerful tool to elucidate the molecular aspects of several biological processes in higher eukaryotes. As in mammalian cells, yeast intracellular Ca(2+) signalling is crucial for a myriad of biological processes. Yeast cells also bear homologs of the major components of the Ca(2+) signalling toolkit in mammalian cells, including channels, co-transporters and pumps. Using yeast single- and multiple-gene deletion strains of various plasma membrane and organellar Ca(2+) transporters, combined with manipulations to estimate intracellular Ca(2+) storage, we evaluated the contribution of individual transport systems to intracellular Ca(2+) homeostasis. Yeast strains lacking Pmr1 and/or Cod1, two ion pumps implicated in ER/Golgi Ca(2+) homeostasis, displayed a fragmented vacuolar phenotype and showed increased vacuolar Ca(2+) uptake and Ca(2+) influx across the plasma membrane. In the pmr1Δ strain, these effects were insensitive to calcineurin activity, independent of Cch1/Mid1 Ca(2+) channels and Pmc1 but required Vcx1. By contrast, in the cod1Δ strain increased vacuolar Ca(2+) uptake was not affected by Vcx1 deletion but was largely dependent on Pmc1 activity. Our analysis further corroborates the distinct roles of Vcx1 and Pmc1 in vacuolar Ca(2+) uptake and point to the existence of not-yet identified Ca(2+) influx pathways.

  16. The Role of Extracellular Ca2+Influx, Intracellular Ca2+ Release and Calmodulin in Mouse Egg Fertilization

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The effects of various Ca2+-modifying drugs on moue egg fertilization were studied. Ca2+ chelator, ethylen glycol-bis-(2-aminoethyl)-tetracetic acid (EGTA) ,and calmodulin (CaM) antagonist,trifluoperzaine (TFP) ,inhibited fertilization in a dose-dependent manner,whild Ca2+ channel bolcker,verapamil ,did not have any effect. When intracellular Ca2+ release was blocked by 8-(N, N-diethylamino) octy1-3,4,5-trimethoxy- benzonate (TMB-8) or the Ca2+ oscillations were inhibited by an inhibitor of endoplasmic reticulum Ca2+-AT- Pase,thapsigargin,the second polar body emission and pronuclear formation were significantly decreased. In contrast,inhibition of intracellular Ca2+ release via bolckage of inositol 1,4,5-triphosphate (IP3) production by neomycin or lithium did not affect fertilization. The results sugest that both extracellular influx,intracellu- lar Ca2+ release and CaM activation are required for normal fertilization. However ,extracellular influx through voltage-gated Ca2+ channel and intracellular release induced by IP3 are not the only pathways for producing Ca2+ transients in moue eggs.

  17. The Role of Extracellular Ca2+ Influx,Intracellular Ca2+ Release and Calmodulin in Mouse Egg Fertilization

    Institute of Scientific and Technical Information of China (English)

    SunQing-yuan; TanJing-he; 等

    1999-01-01

    The effects of various Ca2+-modifying drugs on moue egg fertilization were studied.Ca2+ chelator,ethylen glycol-bis-(2-aminoethyl)-tetracetic acid(EGTA),and calmodulin(CaM) antagonist,trifluoperzaine (TFP),inhibited fertilization in a dose-dependent manner,whild Ca2+ channel bolcker,verspamil,did not have any effect.When intracellular Ca2+ release was blocked by 8-(N,N-diethylamino) octy 1-3,4,5-trimethoxy-benzonate(TME-8) or the Ca2+ oscillations were inhibited by an inhibitor of endoplasmic reticulum Ca2+-At-Pase,thapsigargin,the second polar body emission and pronuclear formation were significantly decreased.In contrast,inhibition of intracellular Ca2+ release via bolckage of inositol 1,4,5-triphosphate (IP3) production by neomycin or lithium did not affect fertilization.The results sugest that both extracellular influx,intracellular Ca2+ release and CaM activation are required for mormal fertilization.However,extracellular influx through voltage-gated Ca2+ channel and intracellular release induced by IP3 and not the only pathways for producing Ca2+ transients in moue eggs.

  18. Differential contribution of cytoplasmic Ca2+ and Ca2+ influx to gamete fusion and egg activation in maize.

    Science.gov (United States)

    Antoine, A F; Faure, J E; Dumas, C; Feijó, J A

    2001-12-01

    In multicellular organisms, gamete fusion triggers a set of events, collectively known as egg activation, that leads to the development of a new individual. Every species that has been studied shows at least one rise in cytoplasmic Ca2+ concentration ([Ca2+]Cyt) after gamete fusion which is believed to be involved in activation. Yet the source and regulation of this Ca2+ signal and the way it is transduced inside the zygote are controversial. In higher plants, in vitro fertilization (IVF) has enabled the description of a rise in [Ca2+]Cyt (ref. 4) that is sufficient for activation, and of a Ca2+ influx that spreads as a wavefront from the fusion site The relationship between these two responses is unknown. Using a new combination of methods that simultaneously monitor the extracellular flux with a Ca2+-vibrating probe, and [Ca2+]Cyt by widefield imaging, we directly determined that the Ca2+ influx precedes the [Ca2+]Cyt elevation by 40-120 s. In addition, results from experiments using the Ca2+-channel inhibitor gadolinium (Gd3+) suggest that the Ca2+ influx may be necessary for sperm incorporation. We also present evidence for a putative sperm-dependent Gd3+-insensitive localized Ca2+ influx confined to the fusion point.

  19. Photolysis of caged compounds: studying Ca(2+) signaling and activation of Ca(2+)-dependent ion channels.

    Science.gov (United States)

    Almassy, Janos; Yule, David I

    2013-01-01

    A wide variety of signaling molecules have been chemically modified by conjugation to a photolabile chromophore to render the substance temporarily biologically inert. Subsequent exposure to ultraviolet (UV) light can release the active moiety from the "caged" precursor in an experimentally controlled manner. This allows the concentration of active molecule to be precisely manipulated in both time and space. These techniques are particularly useful in experimental protocols designed to investigate the mechanisms underlying Ca(2+) signaling and the activation of Ca(2+)-dependent effectors.

  20. Homer proteins in Ca²⁺ entry.

    Science.gov (United States)

    Jardin, Isaac; López, José J; Berna-Erro, Alejandro; Salido, Ginés M; Rosado, Juan A

    2013-06-01

    The Homer family of proteins consists of three adaptor proteins, Homer1, Homer2 and Homer3, each with various isoforms. Homer1 family presents an EVH1 domain, a coiled coil domain and two leucine zipper domains. Homer proteins regulate a number of Ca2+-handling proteins, including transient receptor potential channels and other Ca2+-permeable channels, ionotropic and metabotropic glutamate receptors, shank scaffolding proteins or endoplasmic reticulum Ca2+ release channels. This review article focuses on the association of Homer 1 proteins with Ca2+-handling proteins and their role on intracellular Ca2+-homeostasis.

  1. ATP hydrolysis is critically required for function of CaV1.3 channels in cochlear inner hair cells via fueling Ca2+ clearance.

    Science.gov (United States)

    Weiler, Simon; Krinner, Stefanie; Wong, Aaron B; Moser, Tobias; Pangršič, Tina

    2014-05-14

    Sound encoding is mediated by Ca(2+) influx-evoked release of glutamate at the ribbon synapse of inner hair cells. Here we studied the role of ATP in this process focusing on Ca(2+) current through CaV1.3 channels and Ca(2+) homeostasis in mouse inner hair cells. Patch-clamp recordings and Ca(2+) imaging demonstrate that hydrolyzable ATP is essential to maintain synaptic Ca(2+) influx in inner hair cells via fueling Ca(2+)-ATPases to avoid an increase in cytosolic [Ca(2+)] and subsequent Ca(2+)/calmodulin-dependent inactivation of CaV1.3 channels.

  2. Effects of the removal of extracellular Ca2+ on [Ca2+]i responses to FCCP and acetate in carotid body glomus cells of adult rabbits.

    Science.gov (United States)

    Sato, M

    1997-09-12

    The effects of the removal of extracellular Ca2+ on the responses of cytosolic concentrations of Ca2+ ([Ca2+]i) to acidic stimuli, a protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) and an organic acid acetate, were examined in clusters of cultured carotid body glomus cells of adult rabbits using fura-2 microfluorometry. Application of FCCP (1 microM) induced an increase in [Ca2+]i (mean +/- S.E.M., 108 +/- 14%). After withdrawal of the protonophore the increased [Ca2+]i returned slowly to a resting level. The [Ca2+]i response was attenuated by an inorganic Ca2+ channel antagonist Ni2+ (2 mM) by 81 +/- 4%, and by an L-type voltage-gated Ca2+ channel antagonist D600 (10 microM) by 53 +/- 13%. The removal of extracellular Ca2+ eliminated the [Ca2+]i response in 71% of the tested cells (n = 17), and depressed it by 68 +/- 6% in the rest. Recovery following stimulation with FCCP in the absence of Ca2+ reversibly produced a rapid and large rise in [Ca2+]i, referred to as a [Ca2+]i rise after Ca2+-free/FCCP. The magnitude of a [Ca2+]i rise after Ca2+-free/FCCP (285 +/- 28%, P < 0.05) was larger than that of an increase in [Ca2+]i induced by FCCP in the presence of Ca2+ and had a correlation with the intensity of the suppression of the [Ca2+]i response by Ca2+ removal. A [Ca2+]i rise after Ca2+-free/FCCP was inhibited mostly by D600. Similarly, recovery following exposure to acetate in the absence of Ca2+ caused a rise in [Ca2+]i, referred to as a [Ca2+]i rise after Ca2+-free/acetate which was sensitive to D600. The magnitude of the [Ca2+]i rise was larger than that of a change in [Ca2+]i caused by acetate in the presence of Ca2+. These results suggest that FCCP-induced increase in [Ca2+]i was, in most cells, due to Ca2+ influx via L-type voltage-gated Ca2+ channels and, in some cells, due to both Ca2+ influx and Ca2+ release from internal Ca2+ pool. The removal of extracellular Ca2+ might modify [Ca2+]i responses to acidic stimuli, causing [Ca2+]i

  3. Inhibitory Gating of Input Comparison in the CA1 Microcircuit.

    Science.gov (United States)

    Milstein, Aaron D; Bloss, Erik B; Apostolides, Pierre F; Vaidya, Sachin P; Dilly, Geoffrey A; Zemelman, Boris V; Magee, Jeffrey C

    2015-09-23

    Spatial and temporal features of synaptic inputs engage integration mechanisms on multiple scales, including presynaptic release sites, postsynaptic dendrites, and networks of inhibitory interneurons. Here we investigate how these mechanisms cooperate to filter synaptic input in hippocampal area CA1. Dendritic recordings from CA1 pyramidal neurons reveal that proximal inputs from CA3 as well as distal inputs from entorhinal cortex layer III (ECIII) sum sublinearly or linearly at low firing rates due to feedforward inhibition, but sum supralinearly at high firing rates due to synaptic facilitation, producing a high-pass filter. However, during ECIII and CA3 input comparison, supralinear dendritic integration is dynamically balanced by feedforward and feedback inhibition, resulting in suppression of dendritic complex spiking. We find that a particular subpopulation of CA1 interneurons expressing neuropeptide Y (NPY) contributes prominently to this dynamic filter by integrating both ECIII and CA3 input pathways and potently inhibiting CA1 pyramidal neuron dendrites.

  4. Structure of the CaMKIIdelta/calmodulin complex reveals the molecular mechanism of CaMKII kinase activation.

    Directory of Open Access Journals (Sweden)

    Peter Rellos

    Full Text Available UNLABELLED: Long-term potentiation (LTP, a long-lasting enhancement in communication between neurons, is considered to be the major cellular mechanism underlying learning and memory. LTP triggers high-frequency calcium pulses that result in the activation of Calcium/Calmodulin (CaM-dependent kinase II (CaMKII. CaMKII acts as a molecular switch because it remains active for a long time after the return to basal calcium levels, which is a unique property required for CaMKII function. Here we describe the crystal structure of the human CaMKIIdelta/Ca2+/CaM complex, structures of all four human CaMKII catalytic domains in their autoinhibited states, as well as structures of human CaMKII oligomerization domains in their tetradecameric and physiological dodecameric states. All four autoinhibited human CaMKIIs were monomeric in the determined crystal structures but associated weakly in solution. In the CaMKIIdelta/Ca2+/CaM complex, the inhibitory region adopted an extended conformation and interacted with an adjacent catalytic domain positioning T287 into the active site of the interacting protomer. Comparisons with autoinhibited CaMKII structures showed that binding of calmodulin leads to the rearrangement of residues in the active site to a conformation suitable for ATP binding and to the closure of the binding groove for the autoinhibitory helix by helix alphaD. The structural data, together with biophysical interaction studies, reveals the mechanism of CaMKII activation by calmodulin and explains many of the unique regulatory properties of these two essential signaling molecules. ENHANCED VERSION: This article can also be viewed as an enhanced version in which the text of the article is integrated with interactive 3-D representations and animated transitions. Please note that a web plugin is required to access this enhanced functionality. Instructions for the installation and use of the Web plugin are available in Text S1.

  5. Influence of isolation media on synaptosomal properties: Intracellular pH, pCa, and Ca sup 2+ uptake

    Energy Technology Data Exchange (ETDEWEB)

    Bandeira-Duarte, C.; Carvalho, C.A.; Cragoe Junior, E.J.; Carvalho, A.P. (Univ. of Coimbra (Portugal))

    1990-03-01

    Preparations of synaptosomes isolated in sucrose or in Na(+)-rich media were compared with respect to internal pH (pHi), internal Ca{sup 2+} concentration ((Ca{sup 2+})i), membrane potential and {sup 45}Ca{sup 2+} uptake due to K+ depolarization and Na{sup +}/Ca{sup 2+} exchange. We found that synaptosomes isolated in sucrose media have a pHi of 6.77 +/- 0.04 and a (Ca{sup 2+})i of about 260 nM, whereas synaptosomes isolated in Na(+)-rich ionic media have a pHi of 6.96 +/- 0.07 and a (Ca{sup 2+})i of 463 nM, but both types of preparations have similar membrane potentials of about -50 mV when placed in choline media. The sucrose preparation takes up Ca{sup 2+} only by voltage sensitive calcium channels (VSCC'S) when K(+)-depolarized, while the Na(+)-rich synaptosomes take up {sup 45}Ca{sup 2+} both by VSCC'S and by Na{sup +}/Ca{sup 2+} exchange. The amiloride derivative 2',4'-dimethylbenzamil (DMB), at 30 microM, inhibits both mechanisms of Ca{sup 2+} influx, but 5-(N-4-chlorobenzyl)-2',4' dimethylbenzamil (CBZ-DMB), at 30 microM, inhibits the Ca{sup 2+} uptake by VSCC'S, but not by Na+/Ca2+ exchange. Thus, DMB and CBZ-DMB permit distinguishing between Ca{sup 2+} flux through channels and through Na{sup +}/Ca{sup 2+} exchange. We point out that the different properties of the two types of synaptosomes studied account for some of the discrepancies in results reported in the literature for studies of Ca{sup 2+} fluxes and neurotransmitter release by different types of preparations of synaptosomes.

  6. Vanadate oligomer inhibition of passive and active Ca2+ translocation by the Ca2+ pump of sarcoplasmic reticulum.

    Science.gov (United States)

    Aureliano, M

    2000-05-30

    'Monovanadate' containing mainly monomeric, dimeric and tetrameric vanadate species or 'decavanadate', containing mainly decameric vanadate species inhibits the passive and the active efflux of Ca2+ through the sarcoplasmic reticulum calcium pump. When the efflux of Ca2+ by sarcoplasmic reticulum vesicles is not associated with ATP synthesis both vanadate solutions inhibit the passive efflux of Ca2+. However, only 'decavanadate' exerts noticeable effects when the efflux of Ca2+ is associated with ATP synthesis being the active efflux of Ca2+ almost completely inhibited by decameric species concentration as low as 40 microM.

  7. The mitochondrial Na+/Ca2+ exchanger plays a key role in the control of cytosolic Ca2+ oscillations

    OpenAIRE

    Hernández-San Miguel, Esther; Vay, Laura; Santo Domingo, Jaime; Domínguez Lobatón, María Carmen; Moreno, Alfredo; Montero, Mayte; Álvarez, Javier

    2006-01-01

    Producción Científica There is increasing evidence that mitochondria play an important role in the control of cytosolic Ca2+ signaling. We show here that the main mitochondrial Ca2+-exit pathway, the mitochondrial Na+/Ca2+ exchanger, controls the pattern of cytosolic Ca2+ oscillations in nonexcitable cells. In HeLa cells, the inhibitor of the mitochondrial Na+/Ca2+ exchanger CGP37157 changed the pattern of the oscillations induced by histamine from a high-frequency irregular one t...

  8. Pycnogenol protects CA3-CA1 synaptic function in a rat model of traumatic brain injury.

    Science.gov (United States)

    Norris, Christopher M; Sompol, Pradoldej; Roberts, Kelly N; Ansari, Mubeen; Scheff, Stephen W

    2016-02-01

    Pycnogenol (PYC) is a patented mix of bioflavonoids with potent anti-oxidant and anti-inflammatory properties. Previously, we showed that PYC administration to rats within hours after a controlled cortical impact (CCI) injury significantly protects against the loss of several synaptic proteins in the hippocampus. Here, we investigated the effects of PYC on CA3-CA1 synaptic function following CCI. Adult Sprague-Dawley rats received an ipsilateral CCI injury followed 15 min later by intravenous injection of saline vehicle or PYC (10 mg/kg). Hippocampal slices from the injured (ipsilateral) and uninjured (contralateral) hemispheres were prepared at seven and fourteen days post-CCI for electrophysiological analyses of CA3-CA1 synaptic function and induction of long-term depression (LTD). Basal synaptic strength was impaired in slices from the ipsilateral, relative to the contralateral, hemisphere at seven days post-CCI and susceptibility to LTD was enhanced in the ipsilateral hemisphere at both post-injury timepoints. No interhemispheric differences in basal synaptic strength or LTD induction were observed in rats treated with PYC. The results show that PYC preserves synaptic function after CCI and provides further rationale for investigating the use of PYC as a therapeutic in humans suffering from neurotrauma.

  9. The mitochondrial Na+/Ca2+ exchanger upregulates glucose dependent Ca2+ signalling linked to insulin secretion.

    Directory of Open Access Journals (Sweden)

    Iulia I Nita

    Full Text Available Mitochondria mediate dual metabolic and Ca(2+ shuttling activities. While the former is required for Ca(2+ signalling linked to insulin secretion, the role of the latter in β cell function has not been well understood, primarily because the molecular identity of the mitochondrial Ca(2+ transporters were elusive and the selectivity of their inhibitors was questionable. This study focuses on NCLX, the recently discovered mitochondrial Na(+/Ca(2+ exchanger that is linked to Ca(2+ signalling in MIN6 and primary β cells. Suppression either of NCLX expression, using a siRNA construct (siNCLX or of its activity, by a dominant negative construct (dnNCLX, enhanced mitochondrial Ca(2+ influx and blocked efflux induced by glucose or by cell depolarization. In addition, NCLX regulated basal, but not glucose-dependent changes, in metabolic rate, mitochondrial membrane potential and mitochondrial resting Ca(2+. Importantly, NCLX controlled the rate and amplitude of cytosolic Ca(2+ changes induced by depolarization or high glucose, indicating that NCLX is a critical and rate limiting component in the cross talk between mitochondrial and plasma membrane Ca(2+ signalling. Finally, knockdown of NCLX expression was followed by a delay in glucose-dependent insulin secretion. These findings suggest that the mitochondrial Na(+/Ca(2+ exchanger, NCLX, shapes glucose-dependent mitochondrial and cytosolic Ca(2+ signals thereby regulating the temporal pattern of insulin secretion in β cells.

  10. Structural basis for the high Ca2+ affinity of the ubiquitous SERCA2b Ca2+ pump.

    Science.gov (United States)

    Vandecaetsbeek, Ilse; Trekels, Mieke; De Maeyer, Marc; Ceulemans, Hugo; Lescrinier, Eveline; Raeymaekers, Luc; Wuytack, Frank; Vangheluwe, Peter

    2009-11-03

    Sarco(endo)plasmic reticulum Ca(2+) ATPase (SERCA) Ca(2+) transporters pump cytosolic Ca(2+) into the endoplasmic reticulum, maintaining a Ca(2+) gradient that controls vital cell functions ranging from proliferation to death. To meet the physiological demand of the cell, SERCA activity is regulated by adjusting the affinity for Ca(2+) ions. Of all SERCA isoforms, the housekeeping SERCA2b isoform displays the highest Ca(2+) affinity because of a unique C-terminal extension (2b-tail). Here, an extensive structure-function analysis of SERCA2b mutants and SERCA1a2b chimera revealed how the 2b-tail controls Ca(2+) affinity. Its transmembrane (TM) segment (TM11) and luminal extension functionally cooperate and interact with TM7/TM10 and luminal loops of SERCA2b, respectively. This stabilizes the Ca(2+)-bound E1 conformation and alters Ca(2+)-transport kinetics, which provides the rationale for the higher apparent Ca(2+) affinity. Based on our NMR structure of TM11 and guided by mutagenesis results, a structural model was developed for SERCA2b that supports the proposed 2b-tail mechanism and is reminiscent of the interaction between the alpha- and beta-subunits of Na(+),K(+)-ATPase. The 2b-tail interaction site may represent a novel target to increase the Ca(2+) affinity of malfunctioning SERCA2a in the failing heart to improve contractility.

  11. Ca2+ Influx via the Na+/Ca2+ Exchanger Is Enhanced in Malignant Hyperthermia Skeletal Muscle*

    Science.gov (United States)

    Altamirano, Francisco; Eltit, José M.; Robin, Gaëlle; Linares, Nancy; Ding, Xudong; Pessah, Isaac N.; Allen, Paul D.; López, José R.

    2014-01-01

    Malignant hyperthermia (MH) is potentially fatal pharmacogenetic disorder of skeletal muscle caused by intracellular Ca2+ dysregulation. NCX is a bidirectional transporter that effluxes (forward mode) or influxes (reverse mode) Ca2+ depending on cellular activity. Resting intracellular calcium ([Ca2+]r) and sodium ([Na+]r) concentrations are elevated in MH susceptible (MHS) swine and murine muscles compared with their normal (MHN) counterparts, although the contribution of NCX is unclear. Lowering [Na+]e elevates [Ca2+]r in both MHN and MHS swine muscle fibers and it is prevented by removal of extracellular Ca2+ or reduced by t-tubule disruption, in both genotypes. KB-R7943, a nonselective NCX3 blocker, reduced [Ca2+]r in both swine and murine MHN and MHS muscle fibers at rest and decreased the magnitude of the elevation of [Ca2+]r observed in MHS fibers after exposure to halothane. YM-244769, a high affinity reverse mode NCX3 blocker, reduces [Ca2+]r in MHS muscle fibers and decreases the amplitude of [Ca2+]r rise triggered by halothane, but had no effect on [Ca2+]r in MHN muscle. In addition, YM-244769 reduced the peak and area under the curve of the Ca2+ transient elicited by high [K+]e and increased its rate of decay in MHS muscle fibers. siRNA knockdown of NCX3 in MHS myotubes reduced [Ca2+]r and the Ca2+ transient area induced by high [K+]e. These results demonstrate a functional NCX3 in skeletal muscle whose activity is enhanced in MHS. Moreover reverse mode NCX3 contributes to the Ca2+ transients associated with K+-induced depolarization and the halothane-triggered MH episode in MHS muscle fibers. PMID:24847052

  12. Ca2+ influx via the Na+/Ca2+ exchanger is enhanced in malignant hyperthermia skeletal muscle.

    Science.gov (United States)

    Altamirano, Francisco; Eltit, José M; Robin, Gaëlle; Linares, Nancy; Ding, Xudong; Pessah, Isaac N; Allen, Paul D; López, José R

    2014-07-04

    Malignant hyperthermia (MH) is potentially fatal pharmacogenetic disorder of skeletal muscle caused by intracellular Ca(2+) dysregulation. NCX is a bidirectional transporter that effluxes (forward mode) or influxes (reverse mode) Ca(2+) depending on cellular activity. Resting intracellular calcium ([Ca(2+)]r) and sodium ([Na(+)]r) concentrations are elevated in MH susceptible (MHS) swine and murine muscles compared with their normal (MHN) counterparts, although the contribution of NCX is unclear. Lowering [Na(+)]e elevates [Ca(2+)]r in both MHN and MHS swine muscle fibers and it is prevented by removal of extracellular Ca(2+) or reduced by t-tubule disruption, in both genotypes. KB-R7943, a nonselective NCX3 blocker, reduced [Ca(2+)]r in both swine and murine MHN and MHS muscle fibers at rest and decreased the magnitude of the elevation of [Ca(2+)]r observed in MHS fibers after exposure to halothane. YM-244769, a high affinity reverse mode NCX3 blocker, reduces [Ca(2+)]r in MHS muscle fibers and decreases the amplitude of [Ca(2+)]r rise triggered by halothane, but had no effect on [Ca(2+)]r in MHN muscle. In addition, YM-244769 reduced the peak and area under the curve of the Ca(2+) transient elicited by high [K(+)]e and increased its rate of decay in MHS muscle fibers. siRNA knockdown of NCX3 in MHS myotubes reduced [Ca(2+)]r and the Ca(2+) transient area induced by high [K(+)]e. These results demonstrate a functional NCX3 in skeletal muscle whose activity is enhanced in MHS. Moreover reverse mode NCX3 contributes to the Ca(2+) transients associated with K(+)-induced depolarization and the halothane-triggered MH episode in MHS muscle fibers.

  13. Induction of CaSR expression circumvents the molecular features of malignant CaSR null colon cancer cells.

    Science.gov (United States)

    Singh, Navneet; Chakrabarty, Subhas

    2013-11-15

    We recently reported on the isolation and characterization of calcium sensing receptor (CaSR) null human colon cancer cells (Singh et al., Int J Cancer 2013; 132: 1996-2005). CaSR null cells possess a myriad of molecular features that are linked to a highly malignant and drug resistant phenotype of colon cancer. The CaSR null phenotype can be maintained in defined human embryonic stem cell culture medium. We now show that the CaSR null cells can be induced to differentiate in conventional culture medium, regained the expression of CaSR with a concurrent reversal of the cellular and molecular features associated with the null phenotype. These features include cellular morphology, expression of colon cancer stem cell markers, expression of survivin and thymidylate synthase and sensitivity to fluorouracil. Other features include the expression of epithelial mesenchymal transition linked molecules and transcription factors, oncogenic miRNAs and tumor suppressive molecule and miRNA. With the exception of cancer stem cell markers, the reversal of molecular features, upon the induction of CaSR expression, is directly linked to the expression and function of CaSR because blocking CaSR induction by shRNA circumvented such reversal. We further report that methylation and demethylation of the CaSR gene promoter underlie CaSR expression. Due to the malignant nature of the CaSR null cells, inclusion of the CaSR null phenotype in disease management may improve on the mortality of this disease. Because CaSR is a robust promoter of differentiation and mediates its action through diverse mechanisms and pathways, inactivation of CaSR may serve as a new paradigm in colon carcinogenesis.

  14. Foeniculum vulgare Mill. increases cytosolic Ca(2+) concentration and inhibits store-operated Ca(2+) entry in vascular endothelial cells.

    Science.gov (United States)

    Han, A Young; Lee, Hui Su; Seol, Geun Hee

    2016-12-01

    This study assessed the effects of essential oil of Foeniculum vulgare Mill. (fennel oil) and of trans-anethole, the main component of fennel oil, on extracellular Ca(2+)-induced store-operated Ca(2+) entry (SOCE) into vascular endothelial (EA) cells and their mechanisms of action. Components of fennel oil were analyzed by gas chromatography-mass spectrometry. Cytosolic Ca(2+) concentration ([Ca(2+)]c) in EA cells was determined using Fura-2 fluorescence. In the presence of extracellular Ca(2+), fennel oil significantly increased [Ca(2+)]c in EA cells; this increase was significantly inhibited by the Ca(2+) channel blockers La(3+) and nifedipine. In contrast, fennel oil induced [Ca(2+)]c was significantly lower in Ca(2+)-free solution, suggesting that fennel oil increases [Ca(2+)]c mainly by enhancing Ca(2+) influx into EA cells. [Ca(2+)]c mobilization by trans-anethole was similar to that of fennel oil. Moreover, SOCE was suppressed by fennel oil and trans-anethole. SOCE was also attenuated by lanthanum (La(3+)), a non-selective cation channel (NSC) blocker; 2-aminoethoxydiphenyl borane (2-APB), an inositol 1,4,5-triphosphate (IP3) receptor inhibitor and SOCE blocker; and U73122, an inhibitor of phospholipase C (PLC). Further, SOCE was more strongly inhibited by La(3+) plus fennel oil or trans-anethole than by La(3+) alone. These findings suggest that fennel oil and trans-anethole significantly inhibit SOCE-induced [Ca(2+)]c increase in vascular endothelial cells and that these reactions may be mediated by NSC, IP3-dependent Ca(2+) mobilization, and PLC activation.

  15. PGC-1{alpha} accelerates cytosolic Ca{sup 2+} clearance without disturbing Ca{sup 2+} homeostasis in cardiac myocytes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Min, E-mail: chenminyx@gmail.com [Institute of Molecular Medicine, State Key Laboratory of Biomembrane and Membrane Biotechnology, Peking University, Beijing 100871 (China); Yunnan Centers for Diseases Prevention and Control, Kunming 650022 (China); Wang, Yanru [Institute of Molecular Medicine, State Key Laboratory of Biomembrane and Membrane Biotechnology, Peking University, Beijing 100871 (China); Qu, Aijuan [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States)

    2010-06-11

    Energy metabolism and Ca{sup 2+} handling serve critical roles in cardiac physiology and pathophysiology. Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1{alpha}) is a multi-functional coactivator that is involved in the regulation of cardiac mitochondrial functional capacity and cellular energy metabolism. However, the regulation of PGC-1{alpha} in cardiac Ca{sup 2+} signaling has not been fully elucidated. To address this issue, we combined confocal line-scan imaging with off-line imaging processing to characterize calcium signaling in cultured adult rat ventricular myocytes expressing PGC-1{alpha} via adenoviral transduction. Our data shows that overexpressing PGC-1{alpha} improved myocyte contractility without increasing the amplitude of Ca{sup 2+} transients, suggesting that myofilament sensitivity to Ca{sup 2+} increased. Interestingly, the decay kinetics of global Ca{sup 2+} transients and Ca{sup 2+} waves accelerated in PGC-1{alpha}-expressing cells, but the decay rate of caffeine-elicited Ca{sup 2+} transients showed no significant change. This suggests that sarcoplasmic reticulum (SR) Ca{sup 2+}-ATPase (SERCA2a), but not Na{sup +}/Ca{sup 2+} exchange (NCX) contribute to PGC-1{alpha}-induced cytosolic Ca{sup 2+} clearance. Furthermore, PGC-1{alpha} induced the expression of SERCA2a in cultured cardiac myocytes. Importantly, overexpressing PGC-1{alpha} did not disturb cardiac Ca{sup 2+} homeostasis, because SR Ca{sup 2+} load and the propensity for Ca{sup 2+} waves remained unchanged. These data suggest that PGC-1{alpha} can ameliorate cardiac Ca{sup 2+} cycling and improve cardiac work output in response to physiological stress. Unraveling the PGC-1{alpha}-calcium handing pathway sheds new light on the role of PGC-1{alpha} in the therapy of cardiac diseases.

  16. Inelastic electron scattering from 48Ca

    Science.gov (United States)

    Wise, J. E.; McCarthy, J. S.; Altemus, R.; Norum, B. E.; Whitney, R. R.; Heisenberg, J.; Dawson, J.; Schwentker, O.

    1985-05-01

    Inelastic electron scattering from 48Ca has been performed over a momentum transfer range from 0.6 to 3.0 fm-1 in both forward and backward directions. Form factors have been obtained for 25 levels up to 10 MeV excitation. Charge and current densities for 11 low lying electric transitions and current densities for two magnetic transitions have been reconstructed in Fourier Bessel analysis. Three high spin states observed in the region of 9 MeV excitation are found to have the dominant configuration ν(1g9/2,1f-17/2)8 - but with a total strength of only 36% predicted for the first 8- in a random-phase-approximation calculation. This is interpreted as evidence for particle-phonon coupling. Comparisons of the extracted densities are made with random-phase-approximation calculations using a zero-range, density-dependent Migdal interaction.

  17. paja de caña

    Directory of Open Access Journals (Sweden)

    David Verdecia Torres

    2005-01-01

    Full Text Available En el presente trabajo se realiza un estudio de la combustión de briquetas cilíndricas macizas de biomasa cañera en particular lo referente a la cinética del proceso de combustión lográndose determinar los tiempos de combustión de cada una de las fases que pudieran ser las controladoras del proceso; la difusión de O2 a través de la película gaseosa, la difusión de los volátiles a través de la capa de ceniza y la reacción química; a partir del modelo del núcleo sin reaccionar

  18. Fast inversion of solar Ca II spectra

    CERN Document Server

    Beck, C; Rezaei, R; Louis, R E

    2014-01-01

    We present a fast (<< 1 s per profile) inversion code for solar Ca II lines. The code uses an archive of spectra that are synthesized prior to the inversion under the assumption of local thermodynamic equilibrium (LTE). We show that it can be successfully applied to spectrograph data or more sparsely sampled spectra from two-dimensional spectrometers. From a comparison to a non-LTE inversion of the same set of spectra, we derive a first-order non-LTE correction to the temperature stratifications derived in the LTE approach. The correction factor is close to unity up to log tau ~ -3 and increases to values of 2.5 and 4 at log tau = -6 in the quiet Sun and the umbra, respectively.

  19. Ca isotope fingerprints of early crust-mantle evolution

    Science.gov (United States)

    Kreissig, K.; Elliott, T.

    2005-01-01

    The utility of 40Ca/ 44Ca as a tracer of pre-existing crustal contributions in early Archaean cratons has been explored to identify traces of Hadean crust and to assess the style of continental growth. The relatively short half-life of 40K (˜1.3 Gy) means that its decay to 40Ca occurs dominantly during early Earth History. If Archaean crust had a significant component derived from a more ancient protolith, as anticipated by "steady state" crustal evolution models, this should be clearly reflected in radiogenic 40Ca/ 44Ca ratios (or positive initial ɛ Ca) in different Archaean cratons. A high precision thermal ionisation technique has been used to analyse the 40Ca/ 44Ca ratios of plagioclase separates and associated whole rocks in ˜3.6 Ga (early Archaean) samples from Zimbabwe and West Greenland. Three out of four tonalite, trondhjemite, granodiorite (TTG) suite samples from Zimbabwe display initial 40Ca/ 44Ca ratios indistinguishable from our measured modern MORB value (i.e., ɛ Ca(3.6) ˜ 0). Greenland samples, however, are very diverse ranging from ɛ Ca(3.7) = 0.1 in mafic pillow lavas and felsic sheets from the Isua supracrustal belt, up to very radiogenic signatures (ɛ Ca(3.7) = 2.9) in both mafic rocks of the Akilia association and felsic TTG from the coastal Amîtsoq gneisses. At face value, these results imply the Zimbabwe crust is juvenile whereas most Greenland samples include an earlier crustal component. Yet the west Greenland craton, as with many Archaean localities, has experienced a complex geological history and the interpretation of age-corrected initial isotope values requires great care. Both felsic and mafic samples from Greenland display ɛ Ca(3.7) so radiogenic that they are not readily explained by crustal growth scenarios. The presence of such radiogenic 40Ca/ 44Ca found in low K/Ca plagioclases requires Ca isotope exchange between plagioclase and whole rock during later metamorphic event(s). In addition the unexpectedly radiogenic Ca

  20. Effect of intracellular Ca2+ and action potential duration on L-type Ca2+ channel inactivation and recovery from inactivation in rabbit cardiac myocytes.

    Science.gov (United States)

    Altamirano, Julio; Bers, Donald M

    2007-07-01

    Ca(2+) current (I(Ca)) recovery from inactivation is necessary for normal cardiac excitation-contraction coupling. In normal hearts, increased stimulation frequency increases force, but in heart failure (HF) this force-frequency relationship (FFR) is often flattened or reversed. Although reduced sarcoplasmic reticulum Ca(2+)-ATPase function may be involved, decreased I(Ca) availability may also contribute. Longer action potential duration (APD), slower intracellular Ca(2+) concentration ([Ca(2+)](i)) decline, and higher diastolic [Ca(2+)](i) in HF could all slow I(Ca) recovery from inactivation, thereby decreasing I(Ca) availability. We measured the effect of different diastolic [Ca(2+)](i) on I(Ca) inactivation and recovery from inactivation in rabbit cardiac myocytes. Both I(Ca) and Ba(2+) current (I(Ba)) were measured. I(Ca) decay was accelerated only at high diastolic [Ca(2+)](i) (600 nM). I(Ba) inactivation was slower but insensitive to [Ca(2+)](i). Membrane potential dependence of I(Ca) or I(Ba) availability was not affected by [Ca(2+)](i) <600 nM. Recovery from inactivation was slowed by both depolarization and high [Ca(2+)](i). We also used perforated patch with action potential (AP)-clamp and normal Ca(2+) transients, using various APDs as conditioning pulses for different frequencies (and to simulate HF APD). Recovery of I(Ca) following longer APD was increasingly incomplete, decreasing I(Ca) availability. Trains of long APs caused a larger I(Ca) decrease than short APD at the same frequency. This effect on I(Ca) availability was exacerbated by slowing twitch [Ca(2+)](i) decline by approximately 50%. We conclude that long APD and slower [Ca(2+)](i) decline lead to cumulative inactivation limiting I(Ca) at high heart rates and might contribute to the negative FFR in HF, independent of altered Ca(2+) channel properties.

  1. Apocalmodulin and Ca2+ calmodulin bind to the same region on the skeletal muscle Ca2+ release channel

    Science.gov (United States)

    Moore, C. P.; Rodney, G.; Zhang, J. Z.; Santacruz-Toloza, L.; Strasburg, G.; Hamilton, S. L.

    1999-01-01

    The skeletal muscle Ca2+ release channel (RYR1) is regulated by calmodulin in both its Ca2+-free (apocalmodulin) and Ca2+-bound (Ca2+ calmodulin) states. Apocalmodulin is an activator of the channel, and Ca2+ calmodulin is an inhibitor of the channel. Both apocalmodulin and Ca2+ calmodulin binding sites on RYR1 are destroyed by a mild tryptic digestion of the sarcoplasmic reticulum membranes, but calmodulin (either form), bound to RYR1 prior to tryptic digestion, protects both the apocalmodulin and Ca2+ calmodulin sites from tryptic destruction. The protected sites are after arginines 3630 and 3637 on RYR1. These studies suggest that both Ca2+ calmodulin and apocalmodulin bind to the same or overlapping regions on RYR1 and block access of trypsin to sites at amino acids 3630 and 3637. This sequence is part of a predicted Ca2+ CaM binding site of amino acids 3614-3642 [Takeshima, H., et al. (1989) Nature 339, 439-445].

  2. Electrodeposition and characterization of CaF{sub 2} and rare earth doped CaF{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Wang Hui; Liu Run, E-mail: runliu@zju.edu.cn; Chen Keli; Shi Xiaofang; Xu Zhude

    2011-07-29

    Calcium fluoride (CaF{sub 2}) and the rare earth doped CaF{sub 2} films have been electrodeposited on indium tin oxide (ITO) electrode through electrochemical generation of acid in aqueous solutions near room temperature. For CaF{sub 2} film electrodeposition, the local pH at ITO surface is lowered by the electrochemical oxidation of ascorbate anion, and then the Ca-ethylene diamine tetraacetic acid disodium complexes which are close to the ITO electrode are decomposed to release free Ca{sup 2+} to react with F{sup -}to form CaF{sub 2} deposit onto ITO. In the same way, RE-doped CaF{sub 2} films have been electrodeposited onto ITO electrode. The morphology of films studied by scanning electron microscopy revealed that they are agglomerated and dense. The films showed a little [111] preferred orientation by X-ray diffraction. It was also proved that doped RE ions were distributed homogeneously in the film by energy dispersive spectroscopy mapping. The optical properties of the electrodeposited CaF{sub 2}, CaF{sub 2}:Eu and CaF{sub 2}:Tb films were studied by photoluminescence, and all films exhibit intense emission peaks.

  3. Peroxisome Ca(2+) homeostasis in animal and plant cells.

    Science.gov (United States)

    Costa, Alex; Drago, Ilaria; Zottini, Michela; Pizzo, Paola; Pozzan, Tullio

    2013-01-01

    Ca(2+) homeostasis in peroxisomes has been an unsolved problem for many years. Recently novel probes to monitor Ca(2+) levels in the lumen of peroxisomes in living cells of both animal and plant cells have been developed. Here we discuss the contrasting results obtained in mammalian cells with chemiluminecsent (aequorin) and fluorescent (cameleon) probes targeted to peroxisomes. We briefly discuss the different characteristics of these probes and the possible pitfalls of the two approaches. We conclude that the contrasting results obtained with the two probes may reflect a heterogeneity among peroxisomes in mammalian cells. We also discuss the results obtained in plant peroxisomes. In particular we demonstrate that Ca(2+) increases in the cytoplasm are mirrored by similar rises of Ca(2+) concentration the lumen of peroxisomes. The increases in peroxisome Ca(2+) level results in the activation of a catalase isoform, CAT3. Other functional roles of peroxisomal Ca(2+) changes in plant physiology are briefly discussed.

  4. On the mechanism of synaptic depression induced by CaMKIIN, an endogenous inhibitor of CaMKII.

    Directory of Open Access Journals (Sweden)

    Camilo Gouet

    Full Text Available Activity-dependent synaptic plasticity underlies, at least in part, learning and memory processes. NMDA receptor (NMDAR-dependent long-term potentiation (LTP is a major synaptic plasticity model. During LTP induction, Ca(2+/calmodulin-dependent protein kinase II (CaMKII is activated, autophosphorylated and persistently translocated to the postsynaptic density, where it binds to the NMDAR. If any of these steps is inhibited, LTP is disrupted. The endogenous CaMKII inhibitor proteins CaMKIINα,β are rapidly upregulated in specific brain regions after learning. We recently showed that transient application of peptides derived from CaMKIINα (CN peptides persistently depresses synaptic strength and reverses LTP saturation, as it allows further LTP induction in previously saturated pathways. The treatment disrupts basal CaMKII-NMDAR interaction and decreases bound CaMKII fraction in spines. To unravel CaMKIIN function and to further understand CaMKII role in synaptic strength maintenance, here we more deeply investigated the mechanism of synaptic depression induced by CN peptides (CN-depression in rat hippocampal slices. We showed that CN-depression does not require glutamatergic synaptic activity or Ca(2+ signaling, thus discarding unspecific triggering of activity-dependent long-term depression (LTD in slices. Moreover, occlusion experiments revealed that CN-depression and NMDAR-LTD have different expression mechanisms. We showed that CN-depression does not involve complex metabolic pathways including protein synthesis or proteasome-mediated degradation. Remarkably, CN-depression cannot be resolved in neonate rats, for which CaMKII is mostly cytosolic and virtually absent at the postsynaptic densities. Overall, our results support a direct effect of CN peptides on synaptic CaMKII-NMDAR binding and suggest that CaMKIINα,β could be critical plasticity-related proteins that may operate as cell-wide homeostatic regulators preventing saturation of

  5. Neuromodulation of the Feedforward Dentate Gyrus-CA3 Microcircuit

    Science.gov (United States)

    Prince, Luke Y.; Bacon, Travis J.; Tigaret, Cezar M.; Mellor, Jack R.

    2016-01-01

    The feedforward dentate gyrus-CA3 microcircuit in the hippocampus is thought to activate ensembles of CA3 pyramidal cells and interneurons to encode and retrieve episodic memories. The creation of these CA3 ensembles depends on neuromodulatory input and synaptic plasticity within this microcircuit. Here we review the mechanisms by which the neuromodulators aceylcholine, noradrenaline, dopamine, and serotonin reconfigure this microcircuit and thereby infer the net effect of these modulators on the processes of episodic memory encoding and retrieval. PMID:27799909

  6. Interactions of vanadate oligomers with sarcoplasmic reticulum Ca(2+)-ATPase.

    Science.gov (United States)

    Aureliano, M; Mdeira, V M

    1994-04-28

    Upon addition of sarcoplasmic reticulum (SR), the line width of tetrameric vanadate signal of 51V-NMR spectra narrowed in the presence of ATP and Ca2+, whereas monomeric vanadate line widths were broadened. Thus, ATP decreases the affinity of the enzyme for tetravanadate whereas it induces the interaction with monomeric vanadate. In the presence of Ca2+ it was observed that tetrameric and decameric vanadate bind to SR ATPase whereas monomeric vanadate only binds to SR when ATP is present. However, decameric vanadate clearly differs from vanadate oligomers present in monovanadate solutions in preventing the accumulation of Ca2+ by sarcoplasmic reticulum (SR) vesicles coupled to ATP hydrolysis. Mg2+ increased the inhibitory effect promoted by decavanadate whereas a slight enhancement of Ca2+ uptake was observed in the presence of monovanadate. For 5 mM Mg2+, a nominal 2 mM vanadium 'decavanadate' solution containing about 190 to 200 microM decameric and less than 100 microM monomeric species depressed the rate of Ca2+ uptake by 50% whereas a nominal 2 mM monovanadate solution containing about 662 microM monomeric, 143 microM dimeric and 252 microM tetrameric species had no effect on the rate of Ca2+ accumulation. However, 2 mM 'decavanadate' inhibits by 75% the SR Ca(2+)-ATPase activity whereas the presence of 2 mM 'monovanadate' produces an inhibitory effect below 50%. Therefore, the Ca:ATP stoichiometry of Ca2+ transport is enhanced by monovanadate. In the presence of oxalate, inhibition of SR Ca(2+)-ATPase activity by these solutions is enhanced to 97% and 86% whereas in the presence of the ionophore lasalocid, the inhibitory values were 87% and 19% for 2 mM decavanadate and 2 mM monovanadate solutions, respectively. Apparently, the increase of vesicular Ca2+ concentration counteracts monovanadate inhibition of SR Ca(2+)-ATPase activity but it does not significantly affect decavanadate inhibition.

  7. SNL/CA Environmental Management System Program Manual.

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Barbara L.

    2007-04-01

    The Sandia National Laboratories, California (SNL/CA) Environmental Management System (EMS) Program Manual documents the elements of the site EMS Program. The SNL/CA EMS Program conforms to the International Standard on Environmental Management Systems, ISO 14001:2004. Elements of the ISO standard overlap with those of Department of Energy (DOE) Order 450.1, thus SNL/CA's EMS program also meets the DOE requirements.

  8. Neuromodulation of the feedforward dentate gyrus-CA3 microcircuit

    OpenAIRE

    Luke Yuri Prince; Travis J Bacon; Tigaret, Cezar M.; Mellor, Jack R.

    2016-01-01

    The feedforward dentate gyrus-CA3 microcircuit in the hippocampus is thought to activate ensembles of CA3 pyramidal cells and interneurons to encode and retrieve episodic memories. The creation of these CA3 ensembles depends on neuromodulatory input and synaptic plasticity within this microcircuit. Here we review the mechanisms by which the neuromodulators aceylcholine, noradrenaline, dopamine, and serotonin reconfigure this microcircuit and thereby infer the net effect of these modulators on...

  9. Neuromodulation of the Feedforward Dentate Gyrus-CA3 Microcircuit

    OpenAIRE

    Prince, Luke; Travis J Bacon; Tigaret, Cezar; Mellor, Jack

    2016-01-01

    The feedforward dentate gyrus-CA3 microcircuit in the hippocampus is thought to activate ensembles of CA3 pyramidal cells and interneurons to encode and retrieve episodic memories. The creation of these CA3 ensembles depends on neuromodulatory input and synaptic plasticity within this microcircuit. Here we review the mechanisms by which the neuromodulators aceylcholine, noradrenaline, dopamine, and serotonin reconfigure this microcircuit and thereby infer the net effect of these modulators on...

  10. Neuromodulation of the Feedforward Dentate Gyrus-CA3 Microcircuit.

    Science.gov (United States)

    Prince, Luke Y; Bacon, Travis J; Tigaret, Cezar M; Mellor, Jack R

    2016-01-01

    The feedforward dentate gyrus-CA3 microcircuit in the hippocampus is thought to activate ensembles of CA3 pyramidal cells and interneurons to encode and retrieve episodic memories. The creation of these CA3 ensembles depends on neuromodulatory input and synaptic plasticity within this microcircuit. Here we review the mechanisms by which the neuromodulators aceylcholine, noradrenaline, dopamine, and serotonin reconfigure this microcircuit and thereby infer the net effect of these modulators on the processes of episodic memory encoding and retrieval.

  11. Expression of Ca2+-ATPase and Na+/Ca2+-exchanger is upregulated during epithelial Ca2+ transport in hypodermal cells of the isopod Porcellio scaber.

    Science.gov (United States)

    Ziegler, A; Weihrauch, D; Towle, D W; Hagedorn, M

    2002-09-01

    It is thought that a plasma membrane Ca(2+)-transport ATPase (PMCA) and a Na(+)/Ca(2+)-exchange (NCE) mechanism are involved in epithelial Ca(2+) transport (ECT) in a variety of crustacean epithelia. The sternal epithelium of the terrestrial isopod Porcellio scaber was used as a model for the analysis of Ca(2+)-extrusion mechanisms in the hypodermal epithelium. Using RT-PCR, we amplified a cDNA fragment of 1173 bp that encodes a protein sequence possessing 72% identity to the PMCA from Drosophila melanogaster and a cDNA fragment of 791 bp encoding a protein sequence with 50% identity to the NCE from Loligo opalescens. Semiquantitative RT-PCR revealed that the expression of both mRNAs increases from the non-Ca(2+)-transporting condition to the stages of CaCO(3) deposit formation and degradation. During Ca(2+)-transporting stages, the expression of PMCA and NCE was larger in the anterior sternal epithelium (ASE) than in the posterior sternal epithelium (PSE). The results demonstrate for the first time the expression of a PMCA and a NCE in the hypodermal epithelium of a crustacean and indicate a contribution of these transport mechanisms in ECT.

  12. Hypervitaminosis D mediates compensatory Ca2+ hyperabsorption in TRPV5 knockout mice.

    NARCIS (Netherlands)

    Renkema, K.Y.R.; Nijenhuis, T.; Eerden, B.C. van der; Kemp, J.W.C.M. van der; Weinans, H.; Leeuwen, J.P.P.M. van; Bindels, R.J.M.; Hoenderop, J.G.J.

    2005-01-01

    Vitamin D plays an important role in Ca(2+) homeostasis by controlling Ca(2+) (re)absorption in intestine, kidney, and bone. The epithelial Ca(2+) channel TRPV5 mediates the Ca(2+) entry step in active Ca(2+) reabsorption. TRPV5 knockout (TRPV5(-/-)) mice show impaired Ca(2+) reabsorption, hypercalc

  13. The influence of the 2-neutron elastic transfer on the fusion of 42Ca + 40Ca

    Directory of Open Access Journals (Sweden)

    Stefanini A.M.

    2016-01-01

    We have measured the fusion excitation function of this system using the 42Ca beam of the XTU Tandem of LNL on a thin 40Ca target enriched to 99.96% in mass 40. Cross sections have been measured down to ≤1 mb. The extracted barrier distribution shows clearly two main peaks. We have performed preliminary CC calculations where the 2+ coupling strengths have been taken from the literature and the schematic 2n pair transfer form factor has been used, with a deformation length σt= 0.39 fm. The excitation function is well reproduced by the calculation including the 2n transfer channel. However, including the octupole excitations destroys the agreement.

  14. OLM interneurons differentially modulate CA3 and entorhinal inputs to hippocampal CA1 neurons.

    Science.gov (United States)

    Leão, Richardson N; Mikulovic, Sanja; Leão, Katarina E; Munguba, Hermany; Gezelius, Henrik; Enjin, Anders; Patra, Kalicharan; Eriksson, Anders; Loew, Leslie M; Tort, Adriano B L; Kullander, Klas

    2012-11-01

    The vast diversity of GABAergic interneurons is believed to endow hippocampal microcircuits with the required flexibility for memory encoding and retrieval. However, dissection of the functional roles of defined interneuron types has been hampered by the lack of cell-specific tools. We identified a precise molecular marker for a population of hippocampal GABAergic interneurons known as oriens lacunosum-moleculare (OLM) cells. By combining transgenic mice and optogenetic tools, we found that OLM cells are important for gating the information flow in CA1, facilitating the transmission of intrahippocampal information (from CA3) while reducing the influence of extrahippocampal inputs (from the entorhinal cortex). Furthermore, we found that OLM cells were interconnected by gap junctions, received direct cholinergic inputs from subcortical afferents and accounted for the effect of nicotine on synaptic plasticity of the Schaffer collateral pathway. Our results suggest that acetylcholine acting through OLM cells can control the mnemonic processes executed by the hippocampus.

  15. Hippocampal CA3 pyramidal cells selectively innervate aspiny interneurons.

    Science.gov (United States)

    Wittner, Lucia; Henze, Darrell A; Záborszky, László; Buzsáki, György

    2006-09-01

    The specific connectivity among principal cells and interneurons determines the flow of activity in neuronal networks. To elucidate the connections between hippocampal principal cells and various classes of interneurons, CA3 pyramidal cells were intracellularly labelled with biocytin in anaesthetized rats and the three-dimensional distribution of their axon collaterals was reconstructed. The sections were double-stained for substance P receptor (SPR)- or metabotropic glutamate receptor 1alpha (mGluR-1alpha)-immunoreactivity to investigate interneuron targets of the CA3 pyramidal cells. SPR-containing interneurons represent a large portion of the GABAergic population, including spiny and aspiny classes. Axon terminals of CA3 pyramidal cells contacted SPR-positive interneuron dendrites in the hilus and in all hippocampal strata in both CA3 and CA1 regions (7.16% of all boutons). The majority of axons formed single contacts (87.5%), but multiple contacts (up to six) on single target neurons were also found. CA3 pyramidal cell axon collaterals innervated several types of morphologically different aspiny SPR-positive interneurons. In contrast, spiny SPR-interneurons or mGluR-1alpha-positive interneurons in the hilus, CA3 and CA1 regions were rarely contacted by the filled pyramidal cells. These findings indicate a strong target selection of CA3 pyramidal cells favouring the activation of aspiny classes of interneurons.

  16. TRPV5-mediated Ca2+ Reabsorption and Hypercalciuria

    Science.gov (United States)

    Renkema, Kirsten Y.; Hoenderop, Joost G. J.; Bindels, René J. M.

    2007-04-01

    The concerted action of the intestine, kidney and bone results in the maintenance of a normal Ca2+ balance, a mechanism that is tightly controlled by the calciotropic hormones vitamin D, parathyroid hormone and calcitonin. Disturbances in the Ca2+ balance have been linked to diverse pathophysiological disorders like urolithiasis, hypertension, electroencephalogram abnormalities and rickets. Importantly, the final amount of Ca2+ that is released from the body is determined in the distal part of the nephron, where active Ca2+ reabsorption occurs. Here, Transient Receptor Potential Vanilloid member 5 (TRPV5), a highly Ca2+-selective channel, has been recognized as the gatekeeper of active Ca2+ reabsorption. The in vivo relevance of TRPV5 has been further investigated by the characterization of TRPV5 knockout (TRPV5-/-) mice, which exhibit severe disturbances in renal Ca2+ handling, such as profound hypercalciuria, intestinal Ca2+ hyperabsorption and reduced bone thickness. Hypercalciuria increases the risk of kidney stone formation in these mice. This review highlights our current knowledge about TRPV5-mediated Ca2+ reabsorption and emphasizes the physiological relevance and the clinical implications related to the TRPV5-/- mice model.

  17. Differential diagnosis of tuberculosis and lung cancer pleural effusion by CEA, CA125,CA50%CEA、CA125、CA50在结核及肺癌性胸水鉴别中的意义

    Institute of Scientific and Technical Information of China (English)

    冯金栋; 赵卫国; 保鹏涛

    2013-01-01

    Objective:To explore the significance of differential diagnosis of pleural effusion by detection of carci-noembryonic antigen (CEA) ,carbohydrate antigen (CA125) and carbohydrate antigen (CA50). Methods: A total of 126 specimens from pleural effusion diagnosed as TB in 70 cases and lung cancer in 56 cases were collected. CEA, CA125,CA50 in the pleural effusion were analyzed. ResuItS:The expression level and sensitivity of CEA and CA50 in pleural effusion of lung cancer was significantly higher than that in tuberculous (P 0.05). The specificity was only 5.71%. Combining CEA with CA125 to diagnose pleural effusion resulted fom lung cancer, the sensitivity was 92. 11% and combining CA125 with CA50 the sensitivity was 95. 24% . When the concetration of CEA was more than 10ng/ml or the concetration of CA125 was more than 2000U/ml,pleural effusion of lung cancer should be highly suspected. Conclusion;The use of CEA.CA125 and CA50 separately,or in combination is helpful to differential diagnosis of pleural effusion resulted from tuberculosis and lung cancer.%目的:探讨癌胚抗原(CEA)、糖类抗原(CA125)、糖类抗原(CA50)在胸水鉴别诊断中的意义.方法:收集已明确胸水性质的标本126例(结核性70例、癌性56例),检测胸水中CEA、CA125、CA50的数值,进行统计分析.结果:肺癌性胸水中CEA、CA50表达水平及敏感度明显高于结核性胸腔积液(P<0.05),特异性分别为95.71%和98.57%.同样CA125在肺癌性胸水中高表达(P<0.05),但两组敏感度无差异(P>0.05),特异性仅为5.71%;CEA和CA125联合诊断肺癌性胸水的敏感度为92.11%,CA125和CA50联合诊断敏感度为95.24%.CEA> 10ng/ml或CA125> 2000U/ml,可初步定为肺癌性胸水.结论:CEA、CA125、CA50单独或联合检测对鉴别诊断结核及肺癌性胸水有重要临床指导意义.

  18. Energetics of ternary nitrides: Li-Ca-Zn-N and Ca-Ta-N systems

    Energy Technology Data Exchange (ETDEWEB)

    McHale, J.M.; Navrotsky, A. [Princeton Univ., NJ (United States); Kowach, G.R.; Balbarin, V.E.; DiSalvo, F.J. [Cornell Univ., Ithaca, NY (United States)

    1997-07-01

    High-temperature oxide melt drop solution calorimetry was used to study the energetics of ternary nitride formation. The standard enthalpies of formation of several binary and ternary nitrides were determined. These values in kJ mol{sup {minus}1} are {Delta}H{sub f}{degrees}(Li{sub 3}N) = {minus}166.1 {+-} 4.8, {Delta}H{sub f}{degrees}(Ca{sub 3}N{sub 2}) = 439.7{+-} 6.6, {Delta}H{sub f}{degrees}(Zn{sub 3}N{sub 2}) = 43.5 {+-} 4.1, {Delta}H{sub f}{degrees}(Ta{sub 3}N{sub 5}) = 849.7 {+-} 11.7, {Delta}H{sub f}{degrees}(Ca{sub 2}ZnN{sub 2}) = {minus}378.9 {+-} 8.6, {Delta}H{sub f}{degrees}(Sr{sub 2}ZnN{sub 2}) = {minus}385.6 {+-} 14.3, {Delta}H{sub f}{degrees}(LiCaN) = {minus}216.8 {+-} 10.8, {Delta}H{sub f}{degrees}(LiZnN) = {minus}137.5 {+-} 6.8, and {Delta}H{sub f}{degrees}(CaTaN{sub 2}) = 1643.8 {+-} 9.6. These enthalpies of formation are small in magnitude compared to analogous values for oxides. However, the enthalpies of formation of the ternaries from binary nitrides can be quite substantial, confirming significant energetic stabilization of ternary nitrides. The energetics of ternary nitride formation appears to be dominated by the acid/base character of the cations. A linear relationship was found between the enthalpies of formation of the ternaries from binary nitrides and the ionic potential ratio of the two cations. 43 refs., 4 tabs.

  19. Activity-dependent upregulation of presynaptic kainate receptors at immature CA3-CA1 synapses.

    Science.gov (United States)

    Clarke, Vernon R J; Molchanova, Svetlana M; Hirvonen, Teemu; Taira, Tomi; Lauri, Sari E

    2014-12-10

    Presynaptic kainate-type glutamate receptors (KARs) regulate glutamate release probability and short-term plasticity in various areas of the brain. Here we show that long-term depression (LTD) in the area CA1 of neonatal rodent hippocampus is associated with an upregulation of tonic inhibitory KAR activity, which contributes to synaptic depression and causes a pronounced increase in short-term facilitation of transmission. This increased KAR function was mediated by high-affinity receptors and required activation of NMDA receptors, nitric oxide (NO) synthetase, and postsynaptic calcium signaling. In contrast, KAR activity was irreversibly downregulated in response to induction of long-term potentiation in a manner that depended on activation of the TrkB-receptor of BDNF. Both tonic KAR activity and its plasticity were restricted to early stages of synapse development and were lost in parallel with maturation of the network due to ongoing BDNF-TrkB signaling. These data show that presynaptic KARs are targets for activity-dependent modulation via diffusible messengers NO and BDNF, which enhance and depress tonic KAR activity at immature synapses, respectively. The plasticity of presynaptic KARs in the developing network allows nascent synapses to shape their response to incoming activity. In particular, upregulation of KAR function after LTD allows the synapse to preferentially pass high-frequency afferent activity. This can provide a potential rescue from synapse elimination by uncorrelated activity and also increase the computational dynamics of the developing CA3-CA1 circuitry.

  20. Crystal Structure and Dielectric Properties of Microwave Ceramics CaLa(CaM)O6 [M = Nb, Sb

    Science.gov (United States)

    Dutta, Alo; Mandal, Sanjay; Kumari, Premlata; Mukhopadhyay, P. K.; Biswas, S. K.; Sinha, T. P.

    2017-01-01

    The dielectric properties of two perovskite oxides CaLa(CaM)O6 [M = Nb, Sb] synthesized by the solid-state reaction technique have been studied in the microwave and radio frequency range. The phase formation and the crystal structure of the materials are investigated by the Rietveld refinement of the x-ray diffraction data at room temperature. The Raman spectrum substantiates the crystal structure of the materials. The temperature dependence of the relaxation frequencies in the radio frequency range follows the Arrhenius law, and the corresponding activation energies are found to be 0.339 eV and 0.346 eV, respectively, for CaLa(CaNb)O6 and CaLa(CaSb)O6. The difference in the values of the dielectric constant and the loss tangent are correlated with the respective crystal structure of the materials.

  1. Crystal Structure and Dielectric Properties of Microwave Ceramics CaLa(CaM)O6 [M = Nb, Sb

    Science.gov (United States)

    Dutta, Alo; Mandal, Sanjay; Kumari, Premlata; Mukhopadhyay, P. K.; Biswas, S. K.; Sinha, T. P.

    2017-03-01

    The dielectric properties of two perovskite oxides CaLa(CaM)O6 [M = Nb, Sb] synthesized by the solid-state reaction technique have been studied in the microwave and radio frequency range. The phase formation and the crystal structure of the materials are investigated by the Rietveld refinement of the x-ray diffraction data at room temperature. The Raman spectrum substantiates the crystal structure of the materials. The temperature dependence of the relaxation frequencies in the radio frequency range follows the Arrhenius law, and the corresponding activation energies are found to be 0.339 eV and 0.346 eV, respectively, for CaLa(CaNb)O6 and CaLa(CaSb)O6. The difference in the values of the dielectric constant and the loss tangent are correlated with the respective crystal structure of the materials.

  2. Estimation Model for Electrical Conductivity of CaF2-CaO-Al2O3 Slags

    Science.gov (United States)

    Shi, Guan-yong; Zhang, Ting-an; Dou, Zhi-he; Niu, Li-ping

    2016-09-01

    Electrical conductivity is one of the most important properties of molten slags. It has an important influence on process parameter selection of the electroslag remelting process. In the present work, a new model for estimating electrical conductivity of high-temperature slags has been proposed via calculating the conductivity by electrical conductivity of pure substances and interaction parameters between the different components in the slag has been proposed. In this model, the Arrhenius law is used to describe the relationship between electrical conductivity and temperature of slags. This model has been successfully applied to the CaF2-Al2O3, CaF2-CaO, and CaO-Al2O3, as well as CaF2-CaO-Al2O3 systems, and the calculated results are in good agreement with the measured values.

  3. Different Levels of CEA, CA153 and CA125 in Milk and Benign and Malignant Nipple Discharge.

    Directory of Open Access Journals (Sweden)

    Song Zhao

    Full Text Available The aim of this study was to assess the diagnostic values of three breast tumor markers (i.e., CEA, CA153 and CA125 in milk and nipple discharge in the prediction of different breast diseases diagnoses.Three hundred thirty-six patients (96 breast cancer and 240 benign disease patients with nipple discharge and a control group of 56 healthy parturient participants were enrolled in the present study. Nipple discharge samples were preoperatively collected from the patients, and milk was collected from the colostrum of the parturient participants. The samples were assayed for the CEA, CA153 and CA125 levels. Cutoff values were determined for the detection of breast diseases using ROC curves.The levels of CEA, CA153 and CA125 were significantly different between the nipple discharge and the milk (all ps < 0.001. In the nipple discharge, the CEA and CA153 levels in the breast cancer group were significantly greater than those in the benign group (all ps < 0.001, and cutoff values of 263.3 ng/mL and 1235.3 U/mL, respectively, were established. However, the expression of CA125 did not differ significantly between the breast cancer and benign groups.Differences in the apparent expression levels of CEA, CA153 and CA125 in patients with nipple discharge and healthy persons were validated. The present data suggest that CEA and CA153 might potentially be useful in the differential diagnoses of benign tumors and breast cancer. CA125 did not seem to be useful for breast cancer detection.

  4. Model-based asessment of an in-vivo predictive relationship from CA1 to CA3 in the rodent hippocampus.

    Science.gov (United States)

    Sandler, Roman A; Song, Dong; Hampson, Robert E; Deadwyler, Sam A; Berger, Theodore W; Marmarelis, Vasilis Z

    2015-02-01

    Although an anatomical connection from CA1 to CA3 via the Entorhinal Cortex (EC) and through backprojecting interneurons has long been known it exist, it has never been examined quantitatively on the single neuron level, in the in-vivo nonpatholgical, nonperturbed brain. Here, single spike activity was recorded using a multi-electrode array from the CA3 and CA1 areas of the rodent hippocampus (N = 7) during a behavioral task. The predictive power from CA3→CA1 and CA1→CA3 was examined by constructing Multivariate Autoregressive (MVAR) models from recorded neurons in both directions. All nonsignificant inputs and models were identified and removed by means of Monte Carlo simulation methods. It was found that 121/166 (73 %) CA3→CA1 models and 96/145 (66 %) CA1→CA3 models had significant predictive power, thus confirming a predictive 'Granger' causal relationship from CA1 to CA3. This relationship is thought to be caused by a combination of truly causal connections such as the CA1→EC→CA3 pathway and common inputs such as those from the Septum. All MVAR models were then examined in the frequency domain and it was found that CA3 kernels had significantly more power in the theta and beta range than those of CA1, confirming CA3's role as an endogenous hippocampal pacemaker.

  5. CATHODIC BEHAVIORS OF CAO IN MOLTEN SALTS CaCl2 AND EQUIMOLAR CaCl2-X(X=NaCl,BaCl2,LiCl)%CaO在CaCl2和等摩尔CaCl2-X(X=NaCl,BaCl2,LiCl)熔盐中的阴极行为

    Institute of Scientific and Technical Information of China (English)

    王淑兰; 王伟; 王川华; 张丽君

    2008-01-01

    采用循环伏安方法研究了1173 K时CaCl2-0.5%CaO(摩尔分数)和等摩尔CaCl2-X-0.5%CaO(X=NaCl,BaCl2,LiCl)熔盐中CaO在Mo电极上的阴极行为.研究结果表明,CaCl2与CaO电离的Ca计具有不同的离子结构和还原电势,在1173 K时其还原峰电势分别为-2.15和-1.51 V.等摩尔混合熔盐CaCl2-x-0.5%CaO(x=NaCl,BaCl2)中,CaO诱发电解质产生低电位沉积,降低了混合熔盐的电化学稳定性.通过阴极扫描电流峰密度与扫描速率的关系,计算出1173 K时CaO电离的Ca2+在CaCl2-0.5%CaO,等摩尔的CaCl2-NaCl-0.5%CaO,CaCl2-BaCl2-0.5%CaO和CaCl2-LiCl-0.5%CaO熔盐中的扩散系数,分别为6.42×10-5,1.56×10-5,1.20×10-5和6.79×10-5 cm2/s.

  6. Effects of Ca2+/CaM Messenger System Inhibitors on Ethylene-Induced Increase in Lycopene Content

    Institute of Scientific and Technical Information of China (English)

    GU Cai-qin; XI Yu-fang; GUAN Jun-feng; LI Guang-min

    2003-01-01

    The changes of lycopene content during ripening and senescence of tomato fruit and the relationship between ethylene glycol-bis (EGTA, Ca2+ chelator), verapamil (Vp, Ca2+ channel blockers), trifluoperazine (TFP), chloropromaize (CPZ) (CaM antagonism) and ethylene-induced increase in lycopene content in tomato fruit were investigated. Lycopene content accumulated obviously during ripening and senescence of tomato fruit after harvest at pink stage. Low temperature inhibited but ethylene enhanced the lycopene content.Meanwhile, ethylene also promoted calmodulin (CaM) content in tomato fruit, which was related to the concentration of ethylene. When EGTA, Vp, TFP and CPZ with ethylene were used to treat tomato fruit, ethylene-induced increase in lycopene content could be reversed, indicating that blocking Ca2+ channel in plasma membrane or chelating extracellular Ca2+ or inhibiting the activity of CaM could decrease the action of ethylene, and suggesting that Ca2+-CaM messenger system may be involved in lycopene increase inducedby ethylene.

  7. Thapsigargin, a tumor promoter, discharges intracellular Ca2+ stores by specific inhibition of the endoplasmic reticulum Ca2(+)-ATPase

    DEFF Research Database (Denmark)

    Thastrup, Ole; Cullen, P J; Drøbak, B K

    1990-01-01

    Thapsigargin, a tumor-promoting sesquiterpene lactone, discharges intracellular Ca2+ in rat hepatocytes, as it does in many vertebrate cell types. It appears to act intracellularly, as incubation of isolated rat liver microsomes with thapsigargin induces a rapid, dose-dependent release of stored Ca....... This hypothesis is strongly supported by the demonstration that thapsigargin causes a rapid inhibition of the Ca2(+)-activated ATPase activity of rat liver microsomes, with an identical dose dependence to that seen in whole cell or isolated microsome Ca2+ discharge. The inhibition of the endoplasmic reticulum...

  8. Flavonoid Myricetin Modulates GABAA Receptor Activity through Activation of Ca2+ Channels and CaMK-II Pathway

    Directory of Open Access Journals (Sweden)

    Xiao Hu Zhang

    2012-01-01

    Full Text Available The flavonoid myricetin is found in several sedative herbs, for example, the St. John's Wort, but its influence on sedation and its possible mechanism of action are unknown. Using patch-clamp technique on a brain slice preparation, the present study found that myricetin promoted GABAergic activity in the neurons of hypothalamic paraventricular nucleus (PVN by increasing the decay time and frequency of the inhibitory currents mediated by GABAA receptor. This effect of myricetin was not blocked by the GABAA receptor benzodiazepine- (BZ- binding site antagonist flumazenil, but by KN-62, a specific inhibitor of the Ca2+/calmodulin-stimulated protein kinase II (CaMK-II. Patch clamp and live Ca2+ imaging studies found that myricetin could increase Ca2+ current and intracellular Ca2+ concentration, respectively, via T- and L-type Ca2+ channels in rat PVN neurons and hypothalamic primary culture neurons. Immunofluorescence staining showed increased phosphorylation of CaMK-II after myricetin incubation in primary culture of rat hypothalamic neurons, and the myricetin-induced CaMK-II phosphorylation was further confirmed by Western blotting in PC-12 cells. The present results suggest that myricetin enhances GABAA receptor activity via calcium channel/CaMK-II dependent mechanism, which is distinctively different from that of most existing BZ-binding site agonists of GABAA receptor.

  9. GABA application to hippocampal CA3 or CA1 stratum lacunosum-moleculare excites an interneuron network.

    Science.gov (United States)

    Perkins, Katherine L

    2002-03-01

    Whole cell voltage-clamp recording and focal application of the neurotransmitter gamma-aminobutyric acid (GABA) were used to investigate the ability of exogenous GABA applied to different locations within the guinea pig hippocampal slice to trigger a giant GABA-mediated postsynaptic current (GPSC) in pyramidal cells. A GPSC reflects the synchronous release of GABA from a group of interneurons. Recordings were done in the presence of 4-aminopyridine (4-AP) and blockers of ionotropic glutamatergic synaptic transmission. Spontaneous GPSCs occurred rhythmically in pyramidal cells under these conditions. Brief focal pressure application of GABA (500 microM; 30-200 ms) to CA3 stratum lacunosum-moleculare (SLM) or to the border between CA3 s. radiatum (SR) and SLM triggered an "all-or-none" GPSC in CA3 and CA1 pyramidal cells that looked like the spontaneous GPSCs. During the refractory period following a spontaneous GPSC, application of GABA could not trigger a GPSC. Both spontaneous GPSCs and GPSCs triggered by exogenous GABA were blocked by suppressing synaptic transmission with high Mg(2+)/low Ca(2+) bath solution. On the other hand, focal application of GABA to CA3 s. oriens (SO) or to proximal SR did not trigger a GPSC in the CA3 pyramidal cell; instead it produced a graded response. Focal application of GABA to regions other than CA3 was also tested. Focal application of GABA to CA1 SLM always triggered a GPSC in the CA3 pyramidal cell. Focal application of GABA within the outer two-thirds of the dentate molecular layer often elicited a GPSC in the CA3 pyramidal cell. In contrast, focal application of GABA to CA1 SO, to CA1 SR, or to the hilus elicited no current response in the CA3 pyramidal cell. These data indicate that the GPSC recorded in pyramidal cells that was triggered by focal GABA application resulted from the synchronous synaptic release of GABA from activated interneurons rather than from the binding of exogenous GABA to receptors on the pyramidal cell

  10. The Expression of CaN and CaMK is Associated with Lipogenesis in the Muscle of Chicken

    Institute of Scientific and Technical Information of China (English)

    Ye YANG; Jiao SONG; Ruiqi FUl; Yanfa SUN; Jie WEN

    2015-01-01

    IntramuscuIar fat (IMF) content in chickens significantIy contributes to meat quality. The maln objective of this study was to assess the expression of calcineurin (CaN) and Ca2+/calmoduIin-dependent protein kinase (CaMK) in Iipogene-sis in chicken muscIe. The chickens were sIaughtered and sampIed at the ages of 4, 8, and 16 weeks, respectiveIy. IMF content and the expression of CaN subunits and CaMK isoforms were measured in thigh muscIe tissue. The resuIts showed that the IMF contents were higher in chickens at the age of 16 weeks compared with those in chickens at the ages of 4 and 8 weeks (P<0.05). The expression IeveIs of fatty acid synthase (FAS) and fatty acid transIocase CD36 (FAT/CD36) mRNA in 16-week-oId chickens were al significantIy up-reguIated compared with those in 4-week-oId chickens (P<0.05). The mRNA IeveIs of CaNB and CaMK IV in 16-week-oId chickens were significantIy Iower than those in 4-week-oId chickens (P<0.05). But the CaMK II mRNA IeveIs in 16-week-oId chickens were significantIy higher than those in 4-week-oId chickens (P<0.05). To investigate the roIes of CaMK and CaN in adipogenesis, SV ceI s were incubated in standard adipogenesis medium for 24 h and treated with specific inhibitor of CaMK and CaN. The ex-pressions of CCAAT/enhancer binding protein β(C/EBPβ), steroI reguIatory eIement-binding protein 1 (SREBP1) and peroxisome proIiferation-activated receptor γ(PPARγ) were dramatical y enhanced by CsA and CaN inhibitor (P<0.05). KN93, a CaMK II inhibitor, dramatical y repressed the expression of those Iipogenic genes (P<0.05). al the resuIts above indicated that CaN and CaMK had different effects on adipogenesis in the muscIe of chickens.

  11. Spacial compartmentalization of Ca2+ signaling complexes in pancreatic acini.

    Science.gov (United States)

    Xu, X; Zeng, W; Diaz, J; Muallem, S

    1996-10-04

    Imaging [Ca2+]i at high temporal resolution and measuring the properties of Ca2+ signaling in streptolysin O (SLO)-permeabilized cells were used to study the spacial organization of signaling complexes. Sequential stimulation of single cells within pancreatic acini with several Ca2+-mobilizing agonists revealed an agonist-specific pattern and propagation rate of Ca2+ waves in the same cells, with CCK8 stimulating the fastest and bombesin the slowest waves. More importantly, each agonist initiated the wave in a different region of the same cell. On the other hand, repetitive stimulation with the same agonist induced Ca2+ waves of the same pattern that were initiated from the same region of the cell. The agonist-specific Ca2+ signaling does not appear to be the result of coupling to different G proteins as infusion of an anti-Galphaq antibody into the cells through a patch pipette equally inhibited Ca2+ signaling by all agonists. Further evidence for compartmentalization of signaling complexes was developed in permeabilized cells. The time-dependent loss of Ca2+ signaling due to SLO permeabilization occurred in an agonist-specific manner in the sequence cabachol > bombesin > cholecystokinin. Signaling by all agonists could be completely restored with as low as 2 micro guanosine 5'-3-O-(thio)triphosphate (GTPgammaS). At this low concentration GTPgammaS recoupled inositol 1,4,5-trisphosphate production and Ca2+ release, rather than enhancing phospholipase C activity. Priming of Ca2+ signaling by GTPgammaS was agonist-specific. Guanosine 5'-O-(thio)diphosphate (GDPbetaS) uncoupled the ability of signaling complexes to release Ca2+ much better than stimulating inositol 1,4,5-trisphosphate production. The uncoupling of Ca2+ signaling by GDPbetaS was also agonist-specific. The combined findings of agonist-specific initiation sites of the Ca2+ wave and differential access of guanine nucleotides to signaling complexes suggest spacial compartmentalization of Ca2+ signaling

  12. Dehydration transformation in Ca-montmorillonite

    Indian Academy of Sciences (India)

    P Bala; B K Samantaray; S K Srivastava

    2000-02-01

    The present work deals with the dehydration transformation of Ca-montmorillonite in the temperature range 30°–500°C. Thermal, infrared (IR), and X-ray diffraction (XRD) analyses were used to describe the thermal transformation. The microstructural and layer disorder parameters like crystallite size, r.m.s. strain ($\\langle e^2\\rangle^{1/2}$), variation of interlayer spacing (), and proportion of planes which were affected by the defect (), have all been calculated from the (001) basal reflection using the method of variance and Fourier line shape analysis. These investigations revealed that sample underwent transformation from hydrated phase to dehydrated phase at 200°C, and as a consequence, its basal spacing collapsed from 16.02 Å (30°C) to around 10 Å (200°C). This transformation occurred through a wide range of temperature, i.e. within the range 120°–200°C. The crystallite size was maximum at room temperature (30°C), however, the size decreased with increasing temperature in the hydrated phase, whereas the size increased with increasing temperature for the dehydrated phase. The , and $\\langle e^2\\rangle^{1/2}$ of the hydrated and the dehydrated phase increased and decreased, respectively with increase of heating temperature.

  13. RESEM-CA: Validation and testing

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Vineeta; Carroll, William L.; Bourassa, Norman

    2002-09-01

    This report documents the results of an extended comparison of RESEM-CA energy and economic performance predictions with the recognized benchmark tool DOE2.1E to determine the validity and effectiveness of this tool for retrofit design and analysis. The analysis was a two part comparison of patterns of (1) monthly and annual energy consumption of a simple base-case building and controlled variations in it to explore the predictions of load components of each program, and (2) a simplified life-cycle cost analysis of the predicted effects of selected Energy Conservation Measures (ECMs). The study tries to analyze and/or explain the differences that were observed. On the whole, this validation study indicates that RESEM is a promising tool for retrofit analysis. As a result of this study some factors (incident solar radiation, outside air film coefficient, IR radiation) have been identified where there is a possibility of algorithmic improvements. These would have to be made in a way that does not sacrifice the speed of the tool, necessary for extensive parametric search of optimum ECM measures.

  14. On SA, CA, and GA numbers

    CERN Document Server

    Caveney, Geoffrey; Sondow, Jonathan

    2011-01-01

    Gronwall's function $G$ is defined for $n>1$ by $G(n)=\\frac{\\sigma(n)}{n \\log\\log n}$ where $\\sigma(n)$ is the sum of the divisors of $n$. We call an integer $N>1$ a \\emph{GA1 number} if $N$ is composite and $G(N) \\ge G(N/p)$ for all prime factors $p$ of $N$. We say that $N$ is a \\emph{GA2 number} if $G(N) \\ge G(aN)$ for all multiples $aN$ of $N$. In arXiv 1110.5078, we used Robin's and Gronwall's theorems on $G$ to prove that the Riemann Hypothesis (RH) is true if and only if 4 is the only number that is both GA1 and GA2. Here, we study GA1 numbers and GA2 numbers separately. We compare them with superabundant (SA) and colossally abundant (CA) numbers (first studied by Ramanujan). We give algorithms for computing GA1 numbers; the smallest one with more than two prime factors is 183783600, while the smallest odd one is 1058462574572984015114271643676625. We find nineteen GA2 numbers $\\le 5040$, and prove that a GA2 number $N>5040$ exists if and only if RH is false, in which case $N$ is even and $>10^{8576}$.

  15. {sup 48}Ca HETEROGENEITY IN DIFFERENTIATED METEORITES

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hsin-Wei; Lee, Typhoon; Lee, Der-Chuen; Shen, Jason Jiun-San; Chen, Jiang-Chang, E-mail: haart@earth.sinica.edu.tw [Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan (China)

    2011-12-10

    Isotopic heterogeneities of {sup 48}Ca have been found in numerous bulk meteorites that are correlated with {sup 50}Ti and {sup 54}Cr anomalies among differentiated planetary bodies, and the results suggest that a rare subset of neutron-rich Type Ia supernova (nSN Ia) was responsible for contributing these neutron-rich iron-group isotopes into the solar system (SS). The heterogeneity of these isotopes found in differentiated meteorites indicates that the isotopic compositions of the bulk SS are not uniform, and there are significant amounts of nSNe Ia dust incompletely mixed with the rest of SS materials during planetary formation. Combined with the data of now-extinct short-lived nuclide {sup 60}Fe, which can be produced more efficiently from an nSN Ia than a Type II supernova ejecta, the observed planetary-scale isotopic heterogeneity probably reflects a late input of stellar dust grains with neutron-rich nuclear statistical equilibrium nuclides into the early SS.

  16. Interactive effects of organic fertilizer,CaSO4 and amino acid Ca on Fuji apple in Burozem soil in China

    Institute of Scientific and Technical Information of China (English)

    ZHENG Weiwei; CHEN Feng; XU Yuehua; ZHANG Jing; ZHAI Heng

    2007-01-01

    A two-year trial was conducted to test the interactive effects of special-for-apple organic fertilizer,CaSO4,and amino acid Ca on Fuji/Balenghaitang (Malus robusta Rehd.) rootstock in Burozem soil in China.Total Ca,exchangeable Ca,and fruit Ca were significantly improved by the soil application of CaSO4 with the highest exchangeable Ca and fruit Ca observed in Fuji apple trees treated at the rate of 3.5 kg CaSO4 per tree.3.5 kg CaSO4 was divided into two applications,with first application in the first month after full bloom,and the second in the second month after full bloom in summer,progressively to improve fruit Ca concentration.Dividing CaSO4 into two applications in combination with organic fertilizer or amino acid Ca spray,proved to be more effective on improving the fruit Ca concentration,with the highest level of 179.17 mg/kg FW in Fuji apple trees treated with 2 kg CaSO4 applied and amino acid Ca sprayed in the first month after full bloom,1.5 kg CaSO4 applied in summer,organic fertilizer applied in winter.Organic fertilizer applied in winter alone remarkably improved the fruit Ca concentration,as well as storage Ca in roots and stems,and the best effect was observed in Fuji apple trees which were supplemented organic fertilizer (10 kg) in winter and CaSO4 (1 kg)in the first month after full bloom per tree.The effect on Ca increment became less pronounced when the amount of organic fertilizer reached 15 kg or CaSO4 was more than 3.5 kg per tree.There was a positive correlation between the Ca/Mg ratio in soil and fruit,exchangeable Ca,and fruit Ca concentration,while a negative correlation was observed between the N/Ca ratio in fruit,available P,available K in soil,and fruit Ca concentration.Both N/Ca ratio and Ca/Mg ratio in fruit were affected by different fertilization regime,and bitter pit incidence at the end of storage kept acceptable only if N/Ca<17 and Ca/Mg≥7 at harvest.The commercial fertilization regime turned out to be organic fertilizer in

  17. Application value discussion of CEA, CA19-9, CA242, CA72-4 in early diagnosis of rectal cancer%CEA、CA19-9、CA242、CA72-4在直肠癌早期诊断的应用价值探讨

    Institute of Scientific and Technical Information of China (English)

    周永玲

    2015-01-01

    目的:探讨联合检测癌胚抗原(CEA)、糖类抗原19-9(Carbohydrate antigen 19-9,CA19-9)、糖类抗原242(carbohydrate antigen 242,CA242)、糖类抗原72-4(Carbohydrate antigen 72-4,CA72-4)对直肠癌早期诊断价值。方法采用化学发光法联合检测直肠癌组、直肠良性病变组和健康对照组血清中 CEA、CA19-9、CA242、CA72-4浓度,并进行统计学分析。结果直肠癌组患者血清中 CEA、CA19-9、CA242、CA72-4的含量均明显高于直肠良性病变组及健康对照组,差异有统计学意义(P<0.05),直肠良性病变组和健康对照组比较差异无统计学意义,直肠癌组患者血清四项标志物联合检测的阳性率:72.587%(45/62)高于 CEA 单项检测的阳性率61.29%(38/62)。结论联合检测血清中 CEA、CA19-9、CA242、CA72-4含量可有显著的互补性效提高直肠癌的诊断诊断率,是早期筛查直肠癌一中简单,有效的方法。%Objective To investigate early diagnosis value of CEA, CA19-9, CA242, CA72-4 for rectal cancer. Methods applying chemiluminescence combined with testing serum concentrations of CEA,CA19-9,CA242,CA72-4 of rectal cancer, rectal benign lesion, health control group, and carry on statistical analyis. Result CEA, CA19-9, CA242 and CA72-4 contents in serum of rectal cancer groups were significantly higher than rectal benign lesion and healthy control group, and difference shows statistical significance(P<0.05). Comparison between rectal benign lesion and healthy control group shows no statistical significance. And positive rate of combination test for four markers in serum of rectal cancer group was 72.587% (45/62), which was higher than 61.29% (38/62) of CEA test only. Conclusion combination test for CEA, CA19-9, CA242 and CA72-4 contents can significantly improve diagnostic rate of rectal cancer, which is a simple and effective method for early screening of rectal cancer.

  18. Seawater nutrient and carbonate ion concentrations recorded as P/Ca, Ba/Ca, and U/Ca in the deep-sea coral Desmophyllum dianthus

    Science.gov (United States)

    Anagnostou, Eleni; Sherrell, Robert M.; Gagnon, Alex; LaVigne, Michele; Field, M. Paul; McDonough, William F.

    2011-05-01

    As paleoceanographic archives, deep sea coral skeletons offer the potential for high temporal resolution and precise absolute dating, but have not been fully investigated for geochemical reconstructions of past ocean conditions. Here we assess the utility of skeletal P/Ca, Ba/Ca and U/Ca in the deep sea coral D. dianthus as proxies of dissolved phosphate (remineralized at shallow depths), dissolved barium (trace element with silicate-type distribution) and carbonate ion concentrations, respectively. Measurements of these proxies in globally distributed D. dianthus specimens show clear dependence on corresponding seawater properties. Linear regression fits of mean coral Element/Ca ratios against seawater properties yield the equations: P/Ca coral (μmol/mol) = (0.6 ± 0.1) P/Ca sw(μmol/mol) - (23 ± 18), R2 = 0.6, n = 16 and Ba/Ca coral(μmol/mol) = (1.4 ± 0.3) Ba/Ca sw(μmol/mol) + (0 ± 2), R2 = 0.6, n = 17; no significant relationship is observed between the residuals of each regression and seawater temperature, salinity, pressure, pH or carbonate ion concentrations, suggesting that these variables were not significant secondary dependencies of these proxies. Four D. dianthus specimens growing at locations with Ωarag ⩽ 0.6 displayed markedly depleted P/Ca compared to the regression based on the remaining samples, a behavior attributed to an undersaturation effect. These corals were excluded from the calibration. Coral U/Ca correlates with seawater carbonate ion: U/Ca coral(μmol/mol) = (-0.016 ± 0.003) [CO32-] (μmol/kg) + (3.2 ± 0.3), R2 = 0.6, n = 17. The residuals of the U/Ca calibration are not significantly related to temperature, salinity, or pressure. Scatter about the linear calibration lines is attributed to imperfect spatial-temporal matches between the selected globally distributed specimens and available water column chemical data, and potentially to unresolved additional effects. The uncertainties of these initial proxy calibration regressions

  19. Unanimous Model for Describing the Fast Bioluminescence Kinetics of Ca

    NARCIS (Netherlands)

    Eremeeva, Elena V.; Bartsev, Sergey I.; Berkel, van Willem J.H.; Vysotski, Eugene S.

    2017-01-01

    Upon binding their metal ion cofactors, Ca2+-regulated photoproteins display a rapid increase of light signal, which reaches its peak within milliseconds. In the present study, we investigate bioluminescence kinetics of the entire photoprotein family. All five recombinant hydromedusan Ca2+-regulated

  20. 33 CFR 80.1144 - Bodega and Tomales Bay, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bodega and Tomales Bay, CA. 80... INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1144 Bodega and Tomales Bay, CA. (a... of Bodega Harbor North Breakwater to Bodega Harbor Entrance Light 1....

  1. EST Table: CA945997 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available 1085995|ref|XP_972340.1| PREDICTED: similar to S12e ribosomal protein [Tribolium castaneum] CA945997 L9 ... ...CA945997 KI000033 11/12/09 GO hit GO:0003735(structural constituent of ribosome)|GO

  2. EST Table: CA946075 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available CA946075 KI000114 10/09/28 39 %/193 aa ref|XP_969395.1| PREDICTED: similar to conserved hypothetica...l protein [Tribolium castaneum] gb|EFA00804.1| hypothetical protein TcasGA2_TC003691 [Tribolium ca...: similar to conserved hypothetical protein [Tribolium castaneum] FS915960 L9 ...

  3. EST Table: CA946015 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available 34 %/127 aa gi|189237239|ref|XP_971090.2| PREDICTED: similar to sentrin/sumo-specific protease senp7 [Tribolium castaneum] CA946015 L9 ... ...CA946015 KI000054 11/12/09 n.h 10/09/28 33 %/142 aa ref|XP_002427379.1| sentrin/sum

  4. Influence of pairing in double beta decay of48Ca

    Indian Academy of Sciences (India)

    Prianka Roy; Shashi K Dhiman

    2010-03-01

    Two-neutrino decay matrix elements and half-life of 48Ca are calculated after including neutron–proton pairing correlations in projected Hartree–Fock–Bogoliubov (PHFB) formalism. The GT matrix elements in 2 decay are reduced due to broader smearing of Fermi surfaces. Half-life results for 2 decay of 48Ca with np pairing are better than without pairing.

  5. SNL/CA Environmental Management System Program Manual.

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Barbara L.

    2005-09-01

    The Sandia National Laboratories, California (SNL/CA) Environmental Management System (EMS) Program Manual documents the elements of the site EMS Program. The SNL/CA EMS Program was developed in accordance with Department of Energy (DOE) Order 450.1 and incorporates the elements of the International Standard on Environmental Management Systems, ISO 14001.

  6. 76 FR 13017 - Environmental Impact Statement: Los Angeles County, CA

    Science.gov (United States)

    2011-03-09

    ... Federal Highway Administration Environmental Impact Statement: Los Angeles County, CA AGENCY: Federal... Environmental Impact Statement will be prepared for a proposed highway project in Los Angeles County, California...), 2241 N. Eastern Ave., Los Angeles, CA 90032. Pasadena--Lake Avenue Church, (4th floor above Harris...

  7. Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria.

    Science.gov (United States)

    Benzerara, Karim; Skouri-Panet, Feriel; Li, Jinhua; Férard, Céline; Gugger, Muriel; Laurent, Thierry; Couradeau, Estelle; Ragon, Marie; Cosmidis, Julie; Menguy, Nicolas; Margaret-Oliver, Isabel; Tavera, Rosaluz; López-García, Purificación; Moreira, David

    2014-07-29

    Cyanobacteria have played a significant role in the formation of past and modern carbonate deposits at the surface of the Earth using a biomineralization process that has been almost systematically considered induced and extracellular. Recently, a deep-branching cyanobacterial species, Candidatus Gloeomargarita lithophora, was reported to form intracellular amorphous Ca-rich carbonates. However, the significance and diversity of the cyanobacteria in which intracellular biomineralization occurs remain unknown. Here, we searched for intracellular Ca-carbonate inclusions in 68 cyanobacterial strains distributed throughout the phylogenetic tree of cyanobacteria. We discovered that diverse unicellular cyanobacterial taxa form intracellular amorphous Ca-carbonates with at least two different distribution patterns, suggesting the existence of at least two distinct mechanisms of biomineralization: (i) one with Ca-carbonate inclusions scattered within the cell cytoplasm such as in Ca. G. lithophora, and (ii) another one observed in strains belonging to the Thermosynechococcus elongatus BP-1 lineage, in which Ca-carbonate inclusions lie at the cell poles. This pattern seems to be linked with the nucleation of the inclusions at the septum of the cells, showing an intricate and original connection between cell division and biomineralization. These findings indicate that intracellular Ca-carbonate biomineralization by cyanobacteria has been overlooked by past studies and open new perspectives on the mechanisms and the evolutionary history of intra- and extracellular Ca-carbonate biomineralization by cyanobacteria.

  8. Intracellular Ca-carbonate biomineralization is widespread in cyanobacteria

    Science.gov (United States)

    Benzerara, Karim; Skouri-Panet, Feriel; Li, Jinhua; Férard, Céline; Gugger, Muriel; Laurent, Thierry; Couradeau, Estelle; Ragon, Marie; Cosmidis, Julie; Menguy, Nicolas; Margaret-Oliver, Isabel; Tavera, Rosaluz; López-García, Purificación; Moreira, David

    2014-07-01

    Cyanobacteria have played a significant role in the formation of past and modern carbonate deposits at the surface of the Earth using a biomineralization process that has been almost systematically considered induced and extracellular. Recently, a deep-branching cyanobacterial species, Candidatus Gloeomargarita lithophora, was reported to form intracellular amorphous Ca-rich carbonates. However, the significance and diversity of the cyanobacteria in which intracellular biomineralization occurs remain unknown. Here, we searched for intracellular Ca-carbonate inclusions in 68 cyanobacterial strains distributed throughout the phylogenetic tree of cyanobacteria. We discovered that diverse unicellular cyanobacterial taxa form intracellular amorphous Ca-carbonates with at least two different distribution patterns, suggesting the existence of at least two distinct mechanisms of biomineralization: (i) one with Ca-carbonate inclusions scattered within the cell cytoplasm such as in Ca. G. lithophora, and (ii) another one observed in strains belonging to the Thermosynechococcus elongatus BP-1 lineage, in which Ca-carbonate inclusions lie at the cell poles. This pattern seems to be linked with the nucleation of the inclusions at the septum of the cells, showing an intricate and original connection between cell division and biomineralization. These findings indicate that intracellular Ca-carbonate biomineralization by cyanobacteria has been overlooked by past studies and open new perspectives on the mechanisms and the evolutionary history of intra- and extracellular Ca-carbonate biomineralization by cyanobacteria.

  9. {sup 41}Ca measurements at the Zurich AMS facility

    Energy Technology Data Exchange (ETDEWEB)

    Schnabel, C.; Gartenmann, P.; Suter, M. [Eidgenoessische Technische Hochschule, Zurich (Switzerland); Synal, H.A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Gloris, M.; Leya, I.; Michel, R. [Hannover Univ. (Germany); Herpers, U. [Koeln Univ. (Germany)

    1997-09-01

    Proton-induced production cross sections for {sup 41}Ca from Fe and Ni determined using 6 MV tandem accelerator are presented. The calibration of two secondary standard materials to a standard material of {sup 41}Ca concentration determined by PTB (Braunschweig, Germany) has been carried out. (author) 2 figs., 3 refs.

  10. 33 CFR 80.1118 - Marina Del Rey, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Marina Del Rey, CA. 80.1118 Section 80.1118 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1118 Marina Del Rey, CA. (a) A line drawn from Marina Del Rey Breakwater South Light...

  11. Hierarchic stochastic modelling applied to intracellular Ca(2+ signals.

    Directory of Open Access Journals (Sweden)

    Gregor Moenke

    Full Text Available Important biological processes like cell signalling and gene expression have noisy components and are very complex at the same time. Mathematical analysis of such systems has often been limited to the study of isolated subsystems, or approximations are used that are difficult to justify. Here we extend a recently published method (Thurley and Falcke, PNAS 2011 which is formulated in observable system configurations instead of molecular transitions. This reduces the number of system states by several orders of magnitude and avoids fitting of kinetic parameters. The method is applied to Ca(2+ signalling. Ca(2+ is a ubiquitous second messenger transmitting information by stochastic sequences of concentration spikes, which arise by coupling of subcellular Ca(2+ release events (puffs. We derive analytical expressions for a mechanistic Ca(2+ model, based on recent data from live cell imaging, and calculate Ca(2+ spike statistics in dependence on cellular parameters like stimulus strength or number of Ca(2+ channels. The new approach substantiates a generic Ca(2+ model, which is a very convenient way to simulate Ca(2+ spike sequences with correct spiking statistics.

  12. Crystal Structure of the Vanadate-Inhibited Ca2+-ATPase

    DEFF Research Database (Denmark)

    Clausen, Johannes D.; Bublitz, Maike; Arnou, Bertrand Jean-Paul;

    2016-01-01

    Vanadate is the hallmark inhibitor of the P-type ATPase family; however, structural details of its inhibitory mechanism have remained unresolved. We have determined the crystal structure of sarcoplasmic reticulum Ca2+-ATPase with bound vanadate in the absence of Ca2+. Vanadate is bound...

  13. 33 CFR 80.1134 - Monterey Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Monterey Harbor, CA. 80.1134 Section 80.1134 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1134 Monterey Harbor, CA. A line drawn...

  14. 33 CFR 80.1110 - Dana Point Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Dana Point Harbor, CA. 80.1110 Section 80.1110 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1110 Dana Point Harbor, CA. A line drawn...

  15. 33 CFR 80.1136 - Moss Landing Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Moss Landing Harbor, CA. 80.1136 Section 80.1136 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1136 Moss Landing Harbor, CA. A line drawn...

  16. 33 CFR 80.1148 - Noyo River, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Noyo River, CA. 80.1148 Section 80.1148 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1148 Noyo River, CA. A line drawn from...

  17. 33 CFR 80.1152 - Crescent City Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Crescent City Harbor, CA. 80.1152 Section 80.1152 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1152 Crescent City Harbor, CA. A line...

  18. 33 CFR 80.1132 - Estero-Morro Bay, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Estero-Morro Bay, CA. 80.1132 Section 80.1132 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1132 Estero-Morro Bay, CA. A line drawn...

  19. 33 CFR 80.1102 - Santa Catalina Island, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Santa Catalina Island, CA. 80.1102 Section 80.1102 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1102 Santa Catalina Island, CA....

  20. 46 CFR 7.115 - Santa Catalina Island, CA.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Santa Catalina Island, CA. 7.115 Section 7.115 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC BOUNDARY LINES Pacific Coast § 7.115 Santa Catalina Island, CA. (a) A line drawn from the northernmost point of Lion Head...

  1. 33 CFR 80.1138 - Santa Cruz Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Santa Cruz Harbor, CA. 80.1138 Section 80.1138 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1138 Santa Cruz Harbor, CA. A line drawn...

  2. 33 CFR 80.1146 - Albion River, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Albion River, CA. 80.1146 Section 80.1146 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1146 Albion River, CA. A line drawn on an...

  3. 33 CFR 80.1116 - Redondo Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Redondo Harbor, CA. 80.1116 Section 80.1116 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1116 Redondo Harbor, CA. A line drawn...

  4. 33 CFR 80.1142 - San Francisco Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false San Francisco Harbor, CA. 80.1142 Section 80.1142 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1142 San Francisco Harbor, CA. A straight...

  5. 33 CFR 80.1108 - Oceanside Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Oceanside Harbor, CA. 80.1108 Section 80.1108 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1108 Oceanside Harbor, CA. A line drawn...

  6. 33 CFR 80.1126 - Santa Barbara Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Santa Barbara Harbor, CA. 80.1126 Section 80.1126 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1126 Santa Barbara Harbor, CA. A line...

  7. 33 CFR 80.1112 - Newport Bay, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Newport Bay, CA. 80.1112 Section 80.1112 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1112 Newport Bay, CA. A line drawn from...

  8. 33 CFR 80.1106 - Mission Bay, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Mission Bay, CA. 80.1106 Section 80.1106 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1106 Mission Bay, CA. A line drawn from...

  9. 33 CFR 80.1140 - Pillar Point Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Pillar Point Harbor, CA. 80.1140 Section 80.1140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1140 Pillar Point Harbor, CA. A line drawn...

  10. 33 CFR 80.1104 - San Diego Harbor, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false San Diego Harbor, CA. 80.1104 Section 80.1104 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1104 San Diego Harbor, CA. A line drawn...

  11. 33 CFR 80.1130 - San Luis Obispo Bay, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false San Luis Obispo Bay, CA. 80.1130 Section 80.1130 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1130 San Luis Obispo Bay, CA. A line drawn...

  12. 33 CFR 80.1124 - Ventura Marina, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Ventura Marina, CA. 80.1124 Section 80.1124 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1124 Ventura Marina, CA. A line drawn...

  13. 33 CFR 80.1120 - Port Hueneme, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Port Hueneme, CA. 80.1120 Section 80.1120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1120 Port Hueneme, CA. (a) A line drawn...

  14. 33 CFR 80.1150 - Arcata-Humboldt Bay, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Arcata-Humboldt Bay, CA. 80.1150 Section 80.1150 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1150 Arcata-Humboldt Bay, CA. A line drawn...

  15. Integrated Coastal Management in the Province Ca Mau - Vietnam

    NARCIS (Netherlands)

    Stoop, B.; Bouziotas, D.; Hanssen, J.L.J.; Dunnewolt, J.; Postma, M.G.

    2015-01-01

    The province of Ca Mau is the southernmost part of Vietnam and the Mekong Delta. The water system of Ca Mau faces multiple challenges, both in its coastal zone and in its inland regions. the coastal zone in the province. In view of this, this study presents an integrated approach for combined coasta

  16. Model-Based Assessment of an In-Vivo Predictive Relationship from CA1 to CA3 in the Rodent Hippocampus

    OpenAIRE

    Sandler, Roman A.; Song, Dong; Hampson, Robert E.; Deadwyler, Sam A.; Berger, Theodore W; Marmarelis, Vasilis Z.

    2014-01-01

    Although an anatomical connection from CA1 to CA3 via the Entorhinal Cortex (EC) and through backprojecting interneurons has long been known it exist, it has never been examined quantitatively on the single neuron level, in the in-vivo nonpatholgical, nonperturbed brain. Here, single spike activity was recorded using a multi-electrode array from the CA3 and CA1 areas of the rodent hippocampus (N=7) during a behavioral task. The predictive power from CA3→CA1 and CA1→CA3 was examined by constru...

  17. CaCl2对KAlSi3O8-CaSO4-CaCO3反应体系的影响研究%THE INFLUENCE OF CaCl2 AGENT ADDITION ON THE KAlSi3O8-CaSO4-CaCO3 SYSTEM

    Institute of Scientific and Technical Information of China (English)

    石林; 曾小平; 罗汉金

    2010-01-01

    通过CaCl2添加剂对KAlSi3O8-CaSO4-CaCO3体系研究反应温度和反应时间的影响研究,结果表明:随着CaCl2加入量的增多,体系的反应温度下降,反应时间缩短,当CaCl2的加入量为10%时,反应温度可降至1 000℃,反应时问降至25 min,此时KAlSi3O8的转化率仍可高达83.24%.研究CaCl2的加入对KAlSi3O8-CaSO4-CaCO3反应体系动力学过程的影响,得出反应体系符合金斯特林格动力学方程:FK(G)=1-2/3G-(1-G) 2/3=KKt,反应受扩散过程控制,计算出当CaCl2的加入量为10%时,体系的表观活化能可从原来的128.921 kJ/mol下降至58.320 kJ/mol.

  18. Quantifying Ca2+ release and inactivation of Ca2+ release in fast- and slow-twitch muscles.

    Science.gov (United States)

    Barclay, C J

    2012-12-01

    The aims of this study were to quantify the Ca(2+) release underlying twitch contractions of mammalian fast- and slow-twitch muscle and to comprehensively describe the transient inactivation of Ca(2+) release following a stimulus. Experiments were performed using bundles of fibres from mouse extensor digitorum longus (EDL) and soleus muscles. Ca(2+) release was quantified from the amount of ATP used to remove Ca(2+) from the myoplasm following stimulation. ATP turnover by crossbridges was blocked pharmacologically (N-benzyl-p-toluenesulphonamide for EDL, blebbistatin for soleus) and muscle heat production was used as an index of Ca(2+) pump ATP turnover. At 20°C, Ca(2+) release in response to a single stimulus was 34 and 84 μmol (kg muscle)(-1) for soleus and EDL, respectively, and increased with temperature (30°C: soleus, 61 μmol kg(-1); EDL, 168 μmol kg(-1)). Delivery of another stimulus within 100 ms of the first produced a smaller Ca(2+) release. The maximum magnitude of the decrease in Ca(2+) release was greater in EDL than soleus. Ca(2+) release recovered with an exponential time course which was faster in EDL (mean time constant at 20°C, 32.1 ms) than soleus (65.6 ms) and faster at 30°C than at 20°C. The amounts of Ca(2+) released and crossbridge cycles performed are consistent with a scheme in which Ca(2+) binding to troponin-C allowed an average of ∼1.7 crossbridge cycles in the two muscles.

  19. Spin decomposition of the responses of sup 44 Ca and sup 48 Ca to 300 MeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Baker, F.T.; Bimbot, L.; Fergerson, R.W.; Glashausser, C.; Green, A.; Haeusser, O.; Hicks, K.; Jones, K.; Miller, C.A.; Vetterli, M.; Abegg, R.; Beatty, D.; Bonin, B.; Castel, B.; Chen, X.Y.; Cupps, V.; Djalali, C.; Henderson, R.; Jackson, K.P.; Jeppesen, R.; Nakayama, K.; Nanda, S.K.; Sawafta, R.; Yen, S. (University of Georgia, Athens, Georgia 30602 (US) Institut de Physique Nucleaire, F-91406 Orsay, France Rutgers University, Piscataway, New Jersey 08854 Simon Fraser University, Burnaby, Canada V5A1S6 TRIUMF, 4004 Westbrook Mall, Vancouver, Canada V6T2A3 Los Alamos National Laboratory, Los Alamos, New Mexico 87544 Centre d' Etudes Nucleaires de Saclay, 91191 Gif sur Yvette, CEDEX, France Queen' s University, Kingston, Canada K7L3N6 University of Colorado, Boulder, Colorado 80309 University of South Carolina, Columbia, South Carolina 29208 Continuous Electron Beam Accelerator Facility, 12000 Jefferson Ave., Newport News, Virginia 23606 University of Alberta, Edmonton, Canada T6G2J1)

    1991-07-01

    Angular distributions of the double-differential cross section {ital d}{sup 2}{sigma}/{ital d}{Omega} {ital dE}({sigma}) and the spin-flip probability {ital S}{sub {ital n}{ital n}} have been measured for inclusive proton inelastic scattering from {sup 44}Ca at 290 MeV and from {sup 48}Ca at 318 MeV. Excitation energies up to about 50 MeV for {sup 44}Ca and 40 MeV for {sup 48}Ca have been investigated over the laboratory angular ranges of 3{degree} to 12{degree} for {sup 44}Ca and 3{degree} to 9{degree} for {sup 48}Ca. Multipole decompositions of angular distributions of both the spin-flip cross section {sigma}{ital S}{sub {ital n}{ital n}} and the estimated cross section for {Delta}{ital S}=0 transitions have been performed. Distributions of strengths were deduced for {Delta}{ital L}=1, {Delta}{ital S}=0 (the giant dipole), {Delta}{ital L}=2, {Delta}{ital S}=0 (the giant quadrupole), {Delta}{ital L}=0, {Delta}{ital S}=1 (the magnetic dipole), {Delta}{ital L}=1, {Delta}{ital S}=1 (the spin dipole), and {Delta}{ital L}=2, {Delta}{ital S}=1 (the spin quadrupole). The {Delta}{ital S}=0 summed strengths for {sup 44}Ca are lower than for {sup 40}Ca and {sup 48}Ca. The spin-dipole summed strengths are found to be approximately independent of {ital A}. For {sup 48}Ca, essentially all {ital M}1 strength observed was in the 10.23 MeV 1{sup +} state; for {sup 44}Ca, {ital M}1 strength was observed to be fragmented over a range of 7 to 18 Mev.

  20. Spin decomposition of the responses of Ca-44 and Ca-48 to 300 MeV protons

    Energy Technology Data Exchange (ETDEWEB)

    F. T. Baker; L. Bimbot; R. W. Fergerson; C. Glashausser; A. Green; O. Hausser; K. Hicks; K. Jones; C. A. Miller; M. Vetterli; R. Abegg; D. Beatty; B. Bonin; B. Castel; X. Y. Chen; V. Cupps; C. Djalali; R. Henderson; K. P. Jackson; R. Jeppesen; K. Nakayama; S. K. Nanda; R. Sawafta; S. Yen

    1991-07-01

    Angular distributions of the double-differential cross section d2σ/dΩ dE(σ) and the spin-flip probability Snn have been measured for inclusive proton inelastic scattering from 44Ca at 290 MeV and from 48Ca at 318 MeV. Excitation energies up to about 50 MeV for 44Ca and 40 MeV for 48Ca have been investigated over the laboratory angular ranges of 3° to 12° for 44Ca and 3° to 9° for 48Ca. Multipole decompositions of angular distributions of both the spin-flip cross section σSnn and the estimated cross section for ΔS=0 transitions have been performed. Distributions of strengths were deduced for ΔL=1, ΔS=0 (the giant dipole), ΔL=2, ΔS=0 (the giant quadrupole), ΔL=0, ΔS=1 (the magnetic dipole), ΔL=1, ΔS=1 (the spin dipole), and ΔL=2, ΔS=1 (the spin quadrupole). The ΔS=0 summed strengths for 44Ca are lower than for 40Ca and 48Ca. The spin-dipole summed strengths are found to be approximately independent of A. For 48Ca, essentially all M1 strength observed was in the 10.23 MeV 1+ state; for 44Ca, M1 strength was observed to be fragmented over a range of 7 to 18 Mev.

  1. Bioinformatic analysis of CaBP/calneuron proteins reveals a family of highly conserved vertebrate Ca2+-binding proteins

    Directory of Open Access Journals (Sweden)

    Burgoyne Robert D

    2010-04-01

    Full Text Available Abstract Background Ca2+-binding proteins are important for the transduction of Ca2+ signals into physiological outcomes. As in calmodulin many of the Ca2+-binding proteins bind Ca2+ through EF-hand motifs. Amongst the large number of EF-hand containing Ca2+-binding proteins are a subfamily expressed in neurons and retinal photoreceptors known as the CaBPs and the related calneuron proteins. These were suggested to be vertebrate specific but exactly which family members are expressed outside of mammalian species had not been examined. Findings We have carried out a bioinformatic analysis to determine when members of this family arose and the conserved aspects of the protein family. Sequences of human members of the family obtained from GenBank were used in Blast searches to identify corresponding proteins encoded in other species using searches of non-redundant proteins, genome sequences and mRNA sequences. Sequences were aligned and compared using ClustalW. Some families of Ca2+-binding proteins are known to show a progressive expansion in gene number as organisms increase in complexity. In contrast, the results for CaBPs and calneurons showed that a full complement of CaBPs and calneurons are present in the teleost fish Danio rerio and possibly in cartilaginous fish. These findings suggest that the entire family of genes may have arisen at the same time during vertebrate evolution. Certain members of the family (for example the short form of CaBP1 and calneuron 1 are highly conserved suggesting essential functional roles. Conclusions The findings support the designation of the calneurons as a distinct sub-family. While the gene number for CaBPs/calneurons does not increase, a distinctive evolutionary change in these proteins in vertebrates has been an increase in the number of splice variants present in mammals.

  2. Microstructure, In Vitro Corrosion Behavior and Cytotoxicity of Biodegradable Mg-Ca-Zn and Mg-Ca-Zn-Bi Alloys

    Science.gov (United States)

    Bakhsheshi-Rad, H. R.; Hamzah, E.; Tok, H. Y.; Kasiri-Asgarani, M.; Jabbarzare, S.; Medraj, M.

    2017-02-01

    The effects of bismuth (Bi) addition on the microstructure and corrosion behavior of the Mg-Ca-Zn-Bi alloys were evaluated using electron microscopy, electrochemical test and electrochemical impedance spectroscopy. Microstructural observations showed that Mg-1.2Ca-1Zn- xBi ( x = 0.5, 1.5, 3 wt.%) are composed of Mg2Ca, Ca2Mg6Zn3 and Mg3Bi2 phases while a new phase Mg2Bi2Ca appeared after the addition of 5 and 12 wt.% Bi to the Mg-1.2Ca-1Zn alloy. Furthermore, the additions of 0.5 wt.% Bi to the Mg-1.2Ca-1Zn alloy slightly improved the corrosion behavior of the alloy, while further increase in Bi amount from 1.5 to 12 wt.% has a deleterious effect on the corrosion behavior of the ternary Mg-1.2Ca-1Zn alloy which is driven by galvanic coupling effect. Cytotoxicity tests indicate that the Mg-1.2Ca-1Zn presents higher cell viability compared to Mg-1.2Ca-1Zn-0.5Bi alloy. In addition, the cell viability of both alloys increased with increasing incubation time while diluting the extracts to 50% and 10% improved the cell viabilities. The present results suggest that the Mg-1.2Ca-1Zn-0.5Bi can be interesting candidate for the development of degradable biomaterials and it is worthwhile for further investigation in an in vivo environment.

  3. Ca/calmodulin-dependent phosphorylation of endocytic scaffold ITSN1

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    Morderer D. Ye.

    2014-01-01

    Full Text Available ITSN1 is an endocytic scaffold protein with a prominent function in synaptic transmission. It is known that Ca signaling is crucial for the regulation of synaptic proteins functioning. Aim. Checking the possibility of Ca/calmodulin-dependent phosphorylation of ITSN1. Methods. Affinity chromatography, in vitro kinase reaction, Western blotting, gel staining with fluorescent stains. Results. We show that the fraction of calmodulin-binding proteins is able to phosphorylate the recombinant fragments encoding the coiled-coil region and the SH3 domain-containing region of ITSN1 in the presence of Ca ions and calmodulin. Conclusions. The coiled-coil region and the SH3 domain-containing region of ITSN1 undergo Ca/calmodulin-dependent phosphorylation in vitro, suggesting a possible regulation of ITSN1 by Ca signaling.

  4. Ca II Absorbers in the Sloan Digital Sky Survey: Statistics

    CERN Document Server

    Sardane, Gendith M; Rao, Sandhya M

    2014-01-01

    We present the results of a survey for CaII 3934,3969 absorption-line systems culled from ~ 95,000 Sloan Digital Sky Survey (SDSS) Data Release 7 and Data Release 9 quasar spectra. With 435 doublets identified in the catalog, this list is the largest CaII catalog compiled to date, spanning redshifts z = 0.3 A, is n_0=0.017 +/- 0.001. In comparison to MgII surveys, we found that only 3% of MgII systems in the SDSS have CaII, confirming that it is rare to identify CaII in quasar absorption-line surveys. We also report on some preliminary investigations of the nature of the two populations of CaII absorbers, and show that they can likely be distinguished using their MgII properties.

  5. Mitochondrial carbonic anhydrase CA VB: differences in tissue distribution and pattern of evolution from those of CA VA suggest distinct physiological roles.

    Science.gov (United States)

    Shah, G N; Hewett-Emmett, D; Grubb, J H; Migas, M C; Fleming, R E; Waheed, A; Sly, W S

    2000-02-15

    A cDNA for a second mouse mitochondrial carbonic anhydrase (CA) called CA VB was identified by homology to the previously characterized murine CA V, now called CA VA. The full-length cDNA encodes a 317-aa precursor that contains a 33-aa classical mitochondrial leader sequence. Comparison of products expressed from cDNAs for murine CA VB and CA VA in COS cells revealed that both expressed active CAs that localized in mitochondria, and showed comparable activities in crude extracts and in mitochondria isolated from transfected COS cells. Northern blot analyses of total RNAs from mouse tissues and Western blot analyses of mouse tissue homogenates showed differences in tissue-specific expression between CA VB and CA VA. CA VB was readily detected in most tissues, while CA VA expression was limited to liver, skeletal muscle, and kidney. The human orthologue of murine CA VB was recently reported also. Comparison of the CA domain sequence of human CA VB with that reported here shows that the CA domains of CA VB are much more highly conserved between mouse and human (95% identity) than the CA domains of mouse and human CA VAs (78% identity). Analysis of phylogenetic relationships between these and other available human and mouse CA isozyme sequences revealed that mammalian CA VB evolved much more slowly than CA VA, accepting amino acid substitutions at least 4.5 times more slowly since each evolved from its respective human-mouse ancestral gene around 90 million years ago. Both the differences in tissue distribution and the much greater evolutionary constraints on CA VB sequences suggest that CA VB and CA VA have evolved to assume different physiological roles.

  6. Modulation of the matrix redox signaling by mitochondrial Ca(2.).

    Science.gov (United States)

    Santo-Domingo, Jaime; Wiederkehr, Andreas; De Marchi, Umberto

    2015-11-26

    Mitochondria sense, shape and integrate signals, and thus function as central players in cellular signal transduction. Ca(2+) waves and redox reactions are two such intracellular signals modulated by mitochondria. Mitochondrial Ca(2+) transport is of utmost physio-pathological relevance with a strong impact on metabolism and cell fate. Despite its importance, the molecular nature of the proteins involved in mitochondrial Ca(2+) transport has been revealed only recently. Mitochondrial Ca(2+) promotes energy metabolism through the activation of matrix dehydrogenases and down-stream stimulation of the respiratory chain. These changes also alter the mitochondrial NAD(P)H/NAD(P)(+) ratio, but at the same time will increase reactive oxygen species (ROS) production. Reducing equivalents and ROS are having opposite effects on the mitochondrial redox state, which are hard to dissect. With the recent development of genetically encoded mitochondrial-targeted redox-sensitive sensors, real-time monitoring of matrix thiol redox dynamics has become possible. The discoveries of the molecular nature of mitochondrial transporters of Ca(2+) combined with the utilization of the novel redox sensors is shedding light on the complex relation between mitochondrial Ca(2+) and redox signals and their impact on cell function. In this review, we describe mitochondrial Ca(2+) handling, focusing on a number of newly identified proteins involved in mitochondrial Ca(2+) uptake and release. We further discuss our recent findings, revealing how mitochondrial Ca(2+) influences the matrix redox state. As a result, mitochondrial Ca(2+) is able to modulate the many mitochondrial redox-regulated processes linked to normal physiology and disease.

  7. Modulation of the matrix redox signaling by mitochondrial Ca2+

    Institute of Scientific and Technical Information of China (English)

    Jaime; Santo-Domingo; Andreas; Wiederkehr; Umberto; De; Marchi

    2015-01-01

    Mitochondria sense,shape and integrate signals,and thus function as central players in cellular signal transduction. Ca2+ waves and redox reactions are two such intracellular signals modulated by mitochondria. Mitochondrial Ca2+ transport is of utmost physio-pathological relevance with a strong impact on metabolism and cell fate. Despite its importance,the molecular nature of the proteins involvedin mitochondrial Ca2+ transport has been revealed only recently. Mitochondrial Ca2+ promotes energy metabolism through the activation of matrix dehydrogenases and downstream stimulation of the respiratory chain. These changes also alter the mitochondrial NAD(P)H/NAD(P)+ ratio,but at the same time will increase reactive oxygen species(ROS) production. Reducing equivalents and ROS are having opposite effects on the mitochondrial redox state,which are hard to dissect. With the recent development of genetically encoded mitochondrial-targeted redoxsensitive sensors,real-time monitoring of matrix thiol redox dynamics has become possible. The discoveries of the molecular nature of mitochondrial transporters of Ca2+ combined with the utilization of the novel redox sensors is shedding light on the complex relation between mitochondrial Ca2+ and redox signals and their impact on cell function. In this review,we describe mitochondrial Ca2+ handling,focusing on a number of newly identified proteins involved in mitochondrial Ca2+ uptake and release. We further discuss our recent findings,revealing how mitochondrial Ca2+ influences the matrix redox state. As a result,mitochondrial Ca2+ is able to modulate the many mitochondrial redox-regulated processes linked to normal physiology and disease.

  8. Rational application of tumor marker CA 125 in gynecological oncology

    Directory of Open Access Journals (Sweden)

    Đurđević Srđan

    2010-01-01

    Full Text Available Introduction CA 125 determination started in 1981, when Bast et al. discovered monoclonal antibody OC-125 belonging to immunoglobulin G class (IgG1 using Köhler and Milstein's technique of hybridization. CA 125 antigen is produced in amniotic cells of the 7 week-old embryo, while in adults it can be detected in epithelium of most organs which originate from Müller ducts. The upper level of referent values for CA 125 in serum is 35 U/mL and can be seen in about 99% of healthy people. Application of tumor marker CA 125 in gynecological oncology More than 83% of patients with epithelial ovarian carcinoma have elevated values of CA 125 higher than 35 U/mL at the moment of diagnosing the disease. In cases of ovarian carcinoma, preoperatively determined values of CA 125 in serum are correlated with the extent of the expansion of the disease , histological type of tumor and degree of differentiation of malignant cells. Elevated values up to 65 U/mL in serum can also be found in other malignant tumors (pancreas, breast, colon, bladder, lungs, liver and in different benign diseases. The level of serum CA 125 after the surgery can indicate regression or progression of ovarian carcinoma in more than 90% of the patients who had had elevated values of CA125 prior to the surgery. Postoperative levels of CA 125 >35 U/mL in patients with no residual tumor and values >65 U/mL in those with residual tumor implants represent a separate prognostic factor in further course of the disease. Conclusion The importance of continuous determination of CA 125 tumor marker has to be adjusted to each single case.

  9. Isoprenaline enhances local Ca2+ release in cardiac myocytes

    Institute of Scientific and Technical Information of China (English)

    Jian-xin SHEN

    2006-01-01

    Aim: Contraction of cardiac myocytes is controlled by the generation and amplification of intracellular Ca2+ signals. The key step of this process is the coupling between sarcolemma L-type Ca2+ channels (LCCs) and ryanodine receptors (RyRs) in the sarcoplasmic reticulum (SR). β-Adrenergic stimulation is an important regulatory mechanism for this coupling process. But the details underlied the global level, which require local Ca2+ release study are still unclear. The present study is to explore the effects of β-adrenergic stimulation on local Ca2+ release. Methods: Using confocal microscopy combined with loose-seal patch-clamp approaches, effects of isoprenaline (1 μmol·L-1), a β-adrenergic agonist, on local SR Ca2+ release triggered by Ca2+ influx through LCCs in intact rat cardiac myocytes were investigated. Results: Isoprenaline increased the intensity of ensemble averaged local Ca2+ transients, the peak of which displayed a typical bell-shaped voltage-dependence over the membrane voltages ranging from ~-40mV to ~+35mV. Further analysis showed that this enhancement could be explained by the increased coupling fidelity (which refers the increased probability of RyRs activation upon depolarization), and the increased amplitude of evoked Ca2+ sparks (due to more Ca2+ releases through local RyRs). In addition, isoprenaline decreased the first latency, which displayed a typical "U"-shaped voltage-dependence, showing the available acceleration and synchronization of β-adrenergic stimulation on intracellular calcium release. Conclusions: Isoprenaline enhances local Ca2+ release in cardiac myocytes. These results underscore the importance of regulation of β-adrenergic stimulation on local intermolecular signals between LCCs and RyRs in heart cells.

  10. Modelling Ca2+ bound Troponin in Excitation Contraction Coupling

    Directory of Open Access Journals (Sweden)

    Henry G. Zot

    2016-09-01

    Full Text Available To explain disparate decay rates of cytosolic Ca2+ and structural changes in the thin filaments during a twitch, we model the time course of Ca2+ bound troponin (Tn resulting from the free Ca2+ transient of fast skeletal muscle. In fibers stretched beyond overlap, the decay of Ca2+ as measured by a change in fluo 3 fluorescence is significantly slower than the intensity decay of the meridional 1/38.5 nm-1 reflection of Tn; this is not simply explained by considering only the Ca2+ binding properties of Tn alone (Matsuo, T., Iwamoto, H., and Yagi, N. (2010. Biophys. J. 99, 193-200. We apply a comprehensive model that includes the known Ca2+ binding properties of Tn in the context of the thin filament with and without cycling crossbridges. Calculations based on the model predict that the transient of Ca2+ bound Tn correlates with either the fluo 3 time course in muscle with overlapping thin and thick filaments or the intensity of the meridional 1/38.5 nm-1 reflection in overstretched muscle. Hence, cycling crossbridges delay the dissociation of Ca2+ from Tn. Correlation with the fluo 3 fluorescence change is not causal given that the transient of Ca2+ bound Tn depends on sarcomere length, whereas the fluo-3 fluorescence change does not. Transient positions of tropomyosin calculated from the time course of Ca2+ bound Tn are in reasonable agreement with the transient of measured perturbations of the Tn repeat in overlap and non-overlap muscle preparations.

  11. Cytosolic [Ca2+] signaling pathway in macula densa cells.

    Science.gov (United States)

    Peti-Peterdi, J; Bell, P D

    1999-09-01

    Previous micropuncture studies suggested that macula densa (MD) cells might detect variations in luminal sodium chloride concentration ([NaCl]l) through changes in cytosolic calcium ([Ca2+]c). To test this hypothesis, MD [Ca2+]c was measured with fluorescence microscopy using fura 2 in the isolated perfused thick ascending limb with attached glomerulus preparation dissected from rabbit kidney. Tubules were bathed and perfused with a Ringer solution, [NaCl]l was varied and isosmotically replaced with N-methyl-D-glucamine cyclamate. Control [Ca2+]c, during perfusion with 25 mM NaCl and 150 mM NaCl in the bath, averaged 101. 6 +/- 8.2 nM (n = 21). Increasing [NaCl]l to 150 mM elevated [Ca2+]c by 39.1 +/- 5.2 nM (n = 21, P < 0.01). This effect was concentration dependent between zero and 60 mM [NaCl]l. The presence of either luminal furosemide or basolateral nifedipine or 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), a potent Cl- channel blocker, significantly reduced resting [Ca2+]c and abolished the increase in [Ca2+]c in response to increased [NaCl]l. Nifedipine failed to produce a similar inhibitory effect when added exclusively to the luminal perfusate. Also, 100 nM BAY K 8644, a voltage-gated Ca2+ channel agonist, added to the bathing solution increased [Ca2+]c by 33.2 +/- 8.1 nM (n = 5, P < 0.05). These observations suggest that MD cells may detect variations in [NaCl]l through a signaling pathway that includes Na+-2Cl--K+ cotransport, basolateral membrane depolarization via Cl- channels, and Ca2+ entry through voltage-gated Ca2+ channels.

  12. Local Aqueous Solvation Structure Around Ca2+ During Ca2+---Cl– Pair Formation

    Energy Technology Data Exchange (ETDEWEB)

    Baer, Marcel D.; Mundy, Christopher J.

    2016-03-03

    The molecular details of single ion solvation around Ca2+ and ion-pairing of Ca2--Cl- are investigated using ab initio molecular dynamics. The use of empirical dispersion corrections to the BLYP functional are investigated by comparison to experimentally available extended X-ray absorption fine structure (EXAFS) measurements, which probes the first solvation shell in great detail. Besides finding differences in the free-energy for both ion-pairing and the coordination number of ion solvation between the quantum and classical descriptions of interaction, there were important differences found between dispersion corrected and uncorrected density functional theory (DFT). Specifically, we show significantly different free-energy landscapes for both coordination number of Ca2+ and its ion-pairing with Cl- depending on the DFT simulation protocol. Our findings produce a self-consistent treatment of short-range solvent response to the ion and the intermediate to long-range collective response of the electrostatics of the ion-ion interaction to produce a detailed picture of ion-pairing that is consistent with experiment. MDB is supported by MS3 (Materials Synthesis and Simulation Across Scales) Initiative at Pacific Northwest National Laboratory. It was conducted under the Laboratory Directed Research and Development Program at PNNL, a multiprogram national laboratory operated by Battelle for the U.S. Department of Energy. CJM acknowledges support from US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Additional computing resources were generously allocated by PNNL's Institutional Computing program. The authors thank Prof. Tom Beck for discussions

  13. Improved thermoelectric performance of n-type Ca and Ca-Ce filled skutterudites

    Science.gov (United States)

    Thompson, Daniel R.; Liu, Chang; Ellison, Nicole D.; Salvador, James R.; Meyer, Martin S.; Haddad, Daad B.; Wang, Hsin; Cai, W.

    2014-12-01

    Thermoelectric (TE) technology for use in automotive waste heat recovery is being advanced by General Motors with support from the US Department of Energy. Skutterudites are a very promising material for this application of TE technology due to their superior mechanical properties and good TE performance. Double-filled YbxBayCo4Sb12 with ZT values around 1.1 at 750 K are the best performing n-type skutterudites produced on a large scale using an economically viable approach of melt spinning (MS) in conjunction with spark plasma sintering (SPS). Another economical production method on the tons scale, the melt quench annealing (MQA) technique, has been recently claimed by Treibacher Industrie AG, further information is available [G. Rogl et al., Acta Mater. 76, 434-448 (2014)]. A possible hurdle to commercial implementation of these materials is the use of rare earths as the fillers to reduce thermal conductivity and improve the electrical transport properties. It will be shown herein that skutterudites double-filled with Ca and Ce, both of which are lower-cost fillers, display markedly different TE properties depending on whether they are produced by MQA or MS + SPS synthesis techniques. Ca and Ce double-filled skutterudites prepared by MS + SPS have TE properties that are superior to the same compositions prepared by MQA and that are comparable to the best performing Yb and Ba filled materials. Furthermore, the results of this study suggest that the unusually poor transport properties of MQA Ca-filled skutterudites can be ascribed to deleterious secondary phases, which is contrary to reports in the literature attempting to explain these irregularities via band structure features.

  14. Improved thermoelectric performance of n-type Ca and Ca-Ce filled skutterudites

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Daniel R.; Liu, Chang; Ellison, Nicole D. [Optimal CAE, Plymouth, Michigan 48170 (United States); Salvador, James R.; Meyer, Martin S.; Haddad, Daad B. [General Motors Research and Development, Warren, Michigan 48090 (United States); Wang, Hsin; Cai, W. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-12-28

    Thermoelectric (TE) technology for use in automotive waste heat recovery is being advanced by General Motors with support from the US Department of Energy. Skutterudites are a very promising material for this application of TE technology due to their superior mechanical properties and good TE performance. Double-filled Yb{sub x}Ba{sub y}Co{sub 4}Sb{sub 12} with ZT values around 1.1 at 750 K are the best performing n-type skutterudites produced on a large scale using an economically viable approach of melt spinning (MS) in conjunction with spark plasma sintering (SPS). Another economical production method on the tons scale, the melt quench annealing (MQA) technique, has been recently claimed by Treibacher Industrie AG, further information is available [G. Rogl et al., Acta Mater. 76, 434–448 (2014)]. A possible hurdle to commercial implementation of these materials is the use of rare earths as the fillers to reduce thermal conductivity and improve the electrical transport properties. It will be shown herein that skutterudites double-filled with Ca and Ce, both of which are lower-cost fillers, display markedly different TE properties depending on whether they are produced by MQA or MS + SPS synthesis techniques. Ca and Ce double-filled skutterudites prepared by MS + SPS have TE properties that are superior to the same compositions prepared by MQA and that are comparable to the best performing Yb and Ba filled materials. Furthermore, the results of this study suggest that the unusually poor transport properties of MQA Ca-filled skutterudites can be ascribed to deleterious secondary phases, which is contrary to reports in the literature attempting to explain these irregularities via band structure features.

  15. ANALOG I/O MODULE TEST SYSTEM BASED ON EPICS CA PROTOCOL AND ACTIVEX CA INTERFACE

    Energy Technology Data Exchange (ETDEWEB)

    YENG,YHOFF,L.

    2003-10-13

    Analog input (ADC) and output (DAC) modules play a substantial role in device level control of accelerator and large experiment physics control system. In order to get the best performance some features of analog modules including linearity, accuracy, crosstalk, thermal drift and so on have to be evaluated during the preliminary design phase. Gain and offset error calibration and thermal drift compensation (if needed) may have to be done in the implementation phase as well. A natural technique for performing these tasks is to interface the analog VO modules and GPIB interface programmable test instruments with a computer, which can complete measurements or calibration automatically. A difficulty is that drivers of analog modules and test instruments usually work on totally different platforms (vxworks VS Windows). Developing new test routines and drivers for testing instruments under VxWorks (or any other RTOS) platform is not a good solution because such systems have relatively poor user interface and developing such software requires substantial effort. EPICS CA protocol and ActiveX CA interface provide another choice, a PC and LabVIEW based test system. Analog 110 module can be interfaced from LabVIEW test routines via ActiveX CA interface. Test instruments can be controlled via LabVIEW drivers, most of which are provided by instrument vendors or by National Instruments. Labview also provides extensive data analysis and process functions. Using these functions, users can generate powerful test routines very easily. Several applications built for Spallation Neutron Source (SNS) Beam Loss Monitor (BLM) system are described in this paper.

  16. GPR35 activation reduces Ca2+ transients and contributes to the kynurenic acid-dependent reduction of synaptic activity at CA3-CA1 synapses.

    Directory of Open Access Journals (Sweden)

    Rolando Berlinguer-Palmini

    Full Text Available Limited information is available on the brain expression and role of GPR35, a Gi/o coupled receptor activated by kynurenic acid (KYNA. In mouse cultured astrocytes, we detected GPR35 transcript using RT-PCR and we found that KYNA (0.1 to 100 µM decreased forskolin (FRSK-induced cAMP production (p<0.05. Both CID2745687 (3 µM, CID, a recently described GPR35 antagonist, and GPR35 gene silencing significantly prevented the action of KYNA on FRSK-induced cAMP production. In these cultures, we then evaluated whether GPR35 activation was able to modulate intracellular Ca(2+ concentration ([Ca(2+]i and [Ca(2+]i fluxes. We found that both KYNA and zaprinast, a phosphodiesterase (PDE inhibitor and GPR35 agonist, did not modify either basal or peaks of [Ca(2+]i induced by challenging the cells with ATP (30 µM. However, the [Ca(2+]i plateau phase following peak was significantly attenuated by these compounds in a store-operated Ca(2+ channel (SOC-independent manner. The activation of GPR35 by KYNA and zaprinast was also studied at the CA3-CA1 synapse in the rat hippocampus. Evoked excitatory post synaptic currents (eEPSCs were recorded from CA1 pyramidal neurons in acute brain slices. The action of KYNA on GPR35 was pharmacologically isolated by using NMDA and α7 nicotinic receptor blockers and resulted in a significant reduction of eEPSC amplitude. This effect was prevented in the presence of CID. Moreover, zaprinast reduced eEPSC amplitude in a PDE5- and cGMP-independent mechanism, thus suggesting that glutamatergic transmission in this area is modulated by GPR35. In conclusion, GPR35 is expressed in cultured astrocytes and its activation modulates cAMP production and [Ca(2+]i. GPR35 activation may contribute to KYNA effects on the previously reported decrease of brain extracellular glutamate levels and reduction of excitatory transmission.

  17. Interfacial ferromagnetism and exchange bias in CaRuO3/CaMnO3 superlattices.

    Science.gov (United States)

    He, C; Grutter, A J; Gu, M; Browning, N D; Takamura, Y; Kirby, B J; Borchers, J A; Kim, J W; Fitzsimmons, M R; Zhai, X; Mehta, V V; Wong, F J; Suzuki, Y

    2012-11-01

    We have found ferromagnetism in epitaxially grown superlattices of CaRuO(3)/CaMnO(3) that arises in one unit cell at the interface. Scanning transmission electron microscopy and electron energy loss spectroscopy indicate that the difference in magnitude of the Mn valence states between the center of the CaMnO(3) layer and the interface region is consistent with double exchange interaction among the Mn ions at the interface. Polarized neutron reflectivity and the CaMnO(3) thickness dependence of the exchange bias field together indicate that the interfacial ferromagnetism is only limited to one unit cell of CaMnO(3) at each interface. The interfacial moment alternates between the 1 μ(B)/interface Mn ion for even CaMnO(3) layers and the 0.5 μ(B)/interface Mn ion for odd CaMnO(3) layers. This modulation, combined with the exchange bias, suggests the presence of a modulating interlayer coupling between neighboring ferromagnetic interfaces via the antiferromagnetic CaMnO(3) layers.

  18. Co and Mn doping effect in polycrystalline (Ca,La) and (Ca,Pr)FeAs2 superconductors

    Science.gov (United States)

    Yakita, Hiroyuki; Ogino, Hiraku; Sala, Alberto; Okada, Tomoyuki; Yamamoto, Akiyasu; Kishio, Kohji; Iyo, Akira; Eisaki, Hiroshi; Shimoyama, Jun-ichi

    2015-06-01

    The superconducting properties of Mn and Co doped (Ca,RE)FeAs2 ((Ca,RE)112: RE = La, Pr) were investigated. Co doping increased Tc of (Ca,Pr)112 while Mn doping suppressed the superconductivity of (Ca,RE)112. The Co doped (Ca,La)112 exhibited a large diamagnetic screening, as well as sharper superconducting transition than Co-free (Ca,La)112. Tc zero observed in the resistivity measurements increased from 14 to 30 K by Co doping, while {{T}c}onset was not increased. The critical current density, Jc, of Co doped (Ca,La)112 was approximately 2.1 × 104 A cm-2 and 3.2 × 103 A cm-2 at 2 K and 25 K, respectively, at near zero field. These relatively high Jc values and large diamagnetic screening observed in the susceptibility measurements of the polycrystalline bulks are evidence that Co doped (Ca,RE)112 compounds possess bulk superconductivity.

  19. CA-45(2+) MOVEMENTS INDUCED BY CA2+ CHLORIDE IN ISOLATED RAT AORTA UNDER K+-FREE CONDITIONS

    NARCIS (Netherlands)

    WERMELSKIRCHEN, D; NEBEL, U; WIRTH, A; WILFFERT, B

    1991-01-01

    Increasing the extracellular Ca2+ concentration induced a dihydropyridine-insensitive contraction in the isolated rat aorta bathed in K+-free solution. To obtain further insight into the mechanism of this contraction Ca-45(2+) uptake measurements were carried out with isolated rat aorta. Increasing

  20. 45Ca2+movements induced by Ca2+chloride in isolated rat aorta under K+-free conditions

    NARCIS (Netherlands)

    Wermelskirchen, D.; Nebel, U.; Wirth, A.; Wilffert, B.

    1991-01-01

    Increasing the extracellular Ca2+concentration induced a dihydropyridine-insensitive contraction in the isolated rat aorta bathed in K+-free solution. To obtained further insight into the mechanisms of this contraction45Ca2+uptake measurements were carried out with isolated rat aorta. Increasing the

  1. Intracellular Ca2+ stores and Ca2+ influx are both required for BDNF to rapidly increase quantal vesicular transmitter release.

    Science.gov (United States)

    Amaral, Michelle D; Pozzo-Miller, Lucas

    2012-01-01

    Brain-derived neurotrophic factor (BDNF) is well known as a survival factor during brain development as well as a regulator of adult synaptic plasticity. One potential mechanism to initiate BDNF actions is through its modulation of quantal presynaptic transmitter release. In response to local BDNF application to CA1 pyramidal neurons, the frequency of miniature excitatory postsynaptic currents (mEPSC) increased significantly within 30 seconds; mEPSC amplitude and kinetics were unchanged. This effect was mediated via TrkB receptor activation and required both full intracellular Ca(2+) stores as well as extracellular Ca(2+). Consistent with a role of Ca(2+)-permeable plasma membrane channels of the TRPC family, the inhibitor SKF96365 prevented the BDNF-induced increase in mEPSC frequency. Furthermore, labeling presynaptic terminals with amphipathic styryl dyes and then monitoring their post-BDNF destaining in slice cultures by multiphoton excitation microscopy revealed that the increase in frequency of mEPSCs reflects vesicular fusion events. Indeed, BDNF application to CA3-CA1 synapses in TTX rapidly enhanced FM1-43 or FM2-10 destaining with a time course that paralleled the phase of increased mEPSC frequency. We conclude that BDNF increases mEPSC frequency by boosting vesicular fusion through a presynaptic, Ca(2+)-dependent mechanism involving TrkB receptors, Ca(2+) stores, and TRPC channels.

  2. Intracellular Ca2+ Stores and Ca2+ Influx Are Both Required for BDNF to Rapidly Increase Quantal Vesicular Transmitter Release

    Directory of Open Access Journals (Sweden)

    Michelle D. Amaral

    2012-01-01

    Full Text Available Brain-derived neurotrophic factor (BDNF is well known as a survival factor during brain development as well as a regulator of adult synaptic plasticity. One potential mechanism to initiate BDNF actions is through its modulation of quantal presynaptic transmitter release. In response to local BDNF application to CA1 pyramidal neurons, the frequency of miniature excitatory postsynaptic currents (mEPSC increased significantly within 30 seconds; mEPSC amplitude and kinetics were unchanged. This effect was mediated via TrkB receptor activation and required both full intracellular Ca2+ stores as well as extracellular Ca2+. Consistent with a role of Ca2+-permeable plasma membrane channels of the TRPC family, the inhibitor SKF96365 prevented the BDNF-induced increase in mEPSC frequency. Furthermore, labeling presynaptic terminals with amphipathic styryl dyes and then monitoring their post-BDNF destaining in slice cultures by multiphoton excitation microscopy revealed that the increase in frequency of mEPSCs reflects vesicular fusion events. Indeed, BDNF application to CA3-CA1 synapses in TTX rapidly enhanced FM1-43 or FM2-10 destaining with a time course that paralleled the phase of increased mEPSC frequency. We conclude that BDNF increases mEPSC frequency by boosting vesicular fusion through a presynaptic, Ca2+-dependent mechanism involving TrkB receptors, Ca2+ stores, and TRPC channels.

  3. The Ca II triplet in red giant spectra: [Fe/H] determinations and the role of [Ca/Fe

    CERN Document Server

    Da Costa, G S

    2015-01-01

    Measurements are presented and analyzed of the strength of the Ca II triplet lines in red giants in Galactic globular and open clusters, and in a sample of red giants in the LMC disk that have significantly different [Ca/Fe] abundance ratios to the Galactic objects. The Galactic objects are used to generate a calibration between Ca II triplet line strength and [Fe/H], which is then used to estimate [Fe/H]_CaT for the LMC stars. The values are then compared with the [Fe/H]_spec determinations from high dispersion spectroscopy. After allowance for a small systematic offset the two abundance determinations are in excellent agreement. Further, as found in earlier studies, e.g., Battaglia et al. (2008), the difference is only a very weak function of the [Ca/Fe] ratio. For example, changing [Ca/Fe] from +0.3 to -0.2 causes the Ca II based abundance to underestimate [Fe/H]_spec by only ~0.15 dex, assuming a Galactic calibration. Consequently, the Ca II triplet approach to metallicity determinations can be used witho...

  4. Solidification and Immobilization of Heavy metals in Soil using with nano-metallic Ca/CaO Dispersion Mixture

    Directory of Open Access Journals (Sweden)

    Mallampati S. R.

    2013-04-01

    Full Text Available In the present work, the use of nano-metallic calcium (Ca and calcium oxide (CaO dispersion mixture for the immobilization of heavy metals (As, Cd, Cr and Pb in soil was investigated. With simple grinding, 85-90% of heavy metals immobilization could be achieved, while it could be enhanced to 98-100% by grinding with the addition of nano-metallic Ca/CaO dispersion mixture. By SEM-EDS elemental maps as well as semi-quantitative analysis observed that the amount of As, Cd, Cr and Pb measurable on soil particle surface decreases after nano-metallic Ca/CaO treatment. The leachable heavy metals concentrations were reduced, to the concentration lower than the Japan soil elution standard regulatory threshold, i. e., < 0.01 mg/l for As, Cd and Pb and 0.05mg/l for Cr. Whereas, the effect of soil moisture and pH on heavy metals immobilization was not much influenced. The results suggest that nano-metallic Ca/CaO mixture is suitable to be used for the gentle immobilization of heavy metals contaminated soil at normal moisture conditions.

  5. Development of Ca2+ hotspots between Lymnaea neurons during synaptogenesis.

    Science.gov (United States)

    Feng, Zhong-Ping; Grigoriev, Nikita; Munno, David; Lukowiak, Ken; MacVicar, Brian A; Goldberg, Jeffrey I; Syed, Naweed I

    2002-02-15

    Calcium (Ca2+) channel clustering at specific presynaptic sites is a hallmark of mature synapses. However, the spatial distribution patterns of Ca2+ channels at newly formed synapses have not yet been demonstrated. Similarly, it is unclear whether Ca2+ 'hotspots' often observed at the presynaptic sites are indeed target cell contact specific and represent a specialized mechanism by which Ca2+ channels are targeted to select synaptic sites. Utilizing both soma-soma paired (synapsed) and single neurons from the mollusk Lymnaea, we have tested the hypothesis that differential gradients of voltage-dependent Ca2+ signals develop in presynaptic neuron at its contact point with the postsynaptic neuron; and that these Ca2+ hotspots are target cell contact specific. Fura-2 imaging, or two-photon laser scanning microscopy of Calcium Green, was coupled with electrophysiological techniques to demonstrate that voltage-induced Ca2+ gradients (hotspots) develop in the presynaptic cell at its contact point with the postsynaptic neuron, but not in unpaired single cells. The incidence of Ca2+ hotspots coincided with the appearance of synaptic transmission between the paired cells, and these gradients were target cell contact specific. In contrast, the voltage-induced Ca2+ signal in unpaired neurons was uniformly distributed throughout the somata; a similar pattern of Ca2+ gradient was observed in the presynaptic neuron when it was soma-soma paired with a non-synaptic partner cell. Moreover, voltage clamp recording techniques, in conjunction with a fast, optical differential perfusion system, were used to demonstrate that the total whole-cell Ca2+ (or Ba2+) current density in single and paired cells was not significantly different. However, the amplitude of Ba2+ current was significantly higher in the presynaptic cell at its contact side with the postsynaptic neurons, compared with non-contacted regions. In summary, this study demonstrates that voltage-induced Ca2+ hotspots develop

  6. Echinacea-induced cytosolic Ca2+ elevation in HEK293

    Directory of Open Access Journals (Sweden)

    Nikolau Basil J

    2010-11-01

    Full Text Available Abstract Background With a traditional medical use for treatment of various ailments, herbal preparations of Echinacea are now popularly used to improve immune responses. One likely mode of action is that alkamides from Echinacea bind to cannabinoid type 2 (CB2 receptors and induce a transient increase in intracellular Ca2+. Here, we show that unidentified compounds from Echinacea purpurea induce cytosolic Ca2+ elevation in non-immune-related cells, which lack CB2 receptors and that the Ca2+ elevation is not influenced by alkamides. Methods A non-immune human cell line, HEK293, was chosen to evaluate E. purpurea root extracts and constituents as potential regulators of intracellular Ca2+ levels. Changes in cytosolic Ca2+ levels were monitored and visualized by intracellular calcium imaging. U73122, a phospholipase C inhibitor, and 2-aminoethoxydiphenyl borate (2-APB, an antagonist of inositol-1,4,5-trisphosphate (IP3 receptor, were tested to determine the mechanism of this Ca2+ signaling pathway. E. purpurea root ethanol extracts were fractionated by preparative HPLC, screened for bioactivity on HEK293 cells and by GC-MS for potential constituent(s responsible for this bioactivity. Results A rapid transient increase in cytosolic Ca2+ levels occurs when E. purpurea extracts are applied to HEK293 cells. These stimulatory effects are phospholipase C and IP3 receptor dependent. Echinacea-evoked responses could not be blocked by SR 144528, a specific CB2 receptor antagonist, indicating that CB2 is not involved. Ca2+ elevation is sustained after the Echinacea-induced Ca2+ release from intracellular Ca2+ stores; this longer-term effect is abolished by 2-APB, indicating a possible store operated calcium entry involvement. Of 28 HPLC fractions from E. purpurea root extracts, six induce cytosolic Ca2+ increase. Interestingly, GC-MS analysis of these fractions, as well as treatment of HEK293 cells with known individual and combined chemicals, indicates the

  7. Anti-tumor activity of self-charged (Eu,Ca):WO3 and Eu:CaWO4 nanoparticles

    Indian Academy of Sciences (India)

    Cao Lin; Cao Jiexin; Wang Cong; Che Ping; Pan De’an; Alex A Volinsky

    2012-10-01

    Non-stoichiometric (Eu,Ca):WO3 and Eu:CaWO4 nanoparticles with anti-tumor activity are synthesized in a sol–gel method by adding excessive Eu3+ and Ca2+ ions to tungsten oxide crystal structure. Colorimetric assay shows that 10 nm (Eu,Ca):WO3 and Eu:CaWO4 nanoparticles can effectively inhibit growth of mammary cancer cells without any harm to normal cells. Nanoparticles are characterized by X-ray diffraction, high resolution transmission electron microscopy and fluorescence optical spectrometry. Nanomaterials, insoluble in synthesized water, have complicated self-charging surfaces that trap mammary cancer cells. Surface self-charging effect is suggested as the inhibition mechanism.

  8. CaV 3.1 and CaV 3.3 account for T-type Ca2+ current in GH3 cells

    Directory of Open Access Journals (Sweden)

    M.A. Mudado

    2004-06-01

    Full Text Available T-type Ca2+ channels are important for cell signaling by a variety of cells. We report here the electrophysiological and molecular characteristics of the whole-cell Ca2+ current in GH3 clonal pituitary cells. The current inactivation at 0 mV was described by a single exponential function with a time constant of 18.32 ± 1.87 ms (N = 16. The I-V relationship measured with Ca2+ as a charge carrier was shifted to the left when we applied a conditioning pre-pulse of up to -120 mV, indicating that a low voltage-activated current may be present in GH3 cells. Transient currents were first activated at -50 mV and peaked around -20 mV. The half-maximal voltage activation and the slope factors for the two conditions are -35.02 ± 2.4 and 6.7 ± 0.3 mV (pre-pulse of -120 mV, N = 15, and -27.0 ± 0.97 and 7.5 ± 0.7 mV (pre-pulse of -40 mV, N = 9. The 8-mV shift in the activation mid-point was statistically significant (P < 0.05. The tail currents decayed bi-exponentially suggesting two different T-type Ca2+ channel populations. RT-PCR revealed the presence of a1G (CaV3.1 and a1I (CaV3.3 T-type Ca2+ channel mRNA transcripts.

  9. Selective phosphorylation of cationic polypeptide aggregated with phosphatidylserine/diacylglycerol/Ca2+/detergent mixed micelles by Ca(2+)-independent but not Ca(2+)-dependent protein kinase C isozymes.

    Science.gov (United States)

    Mahoney, C W; Huang, K P

    1995-03-14

    Mixed micelles containing Nonidet P40 (NP-40) (829 microM or 4.8 mM), phosphatidylserine (PS) (14.5 or 8 mol%), and 1,2-diacylglycerol (DG) (0.5 or 1 mol%) when preincubated with protein kinase C (PKC) assay mixture containing cationic substrate and CaCl2 (400 microM) formed aggregates in a time-, temperature-, and substrate concentration-dependent manner with a t1/2 approximately 3-12 min (22 degrees C). Concomitant with the formation of these aggregates there was a substantial loss of substrate phosphorylation catalyzed by the Ca(2+)-dependent PKC alpha, beta, and gamma but not the Ca(2+)-independent PKC, delta and epsilon. All cationic PKC substrates tested, neurogranin peptide analog, neurogranin, and histone III-S, formed aggregates with PS/DG/NP-40/Ca2+ mixed micelles in a time-dependent fashion. The poly(cationic-anionic) PKC substrate protamine sulfate also forms aggregates with the mixed micelles in the presence of Ca2+, but without affecting the substrate phosphorylation by the kinase. Under similar conditions, but at 4 degrees C, neither aggregation nor loss of cationic substrate phosphorylation was observed. Another nonionic detergent, octyl glucoside, behaved similarly to NP-40. Phosphatidylinositol (PI) and phosphatidylglycerol like PS, were effective in forming aggregates with NP-40/cationic polypeptide/DG/Ca2+ as monitored by light scattering, yet without affecting substrate phosphorylation. Phosphorylation of cationic substrates by M-kinase, derived from trypsinized PKC beta, was also greatly diminished by the aggregation. In contrast, [3H]phorbol 12,13-dibutyrate binding to PKC beta was unaffected. Formation of the aggregates that were selectively utilized by the Ca(2+)-independent PKCs was dependent on the ratio of cationic substrate to the number of mixed micelles.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Development and evaluation of materials for thermochemical heat storage based on the CaO/CaCO3 reaction couple

    Science.gov (United States)

    Sakellariou, Kyriaki G.; Tsongidis, Nikolaos I.; Karagiannakis, George; Konstandopoulos, Athanasios G.; Baciu, Diana; Charalambopoulou, Georgia; Steriotis, Theodore; Stubos, Athanasios; Arlt, Wolfgang

    2016-05-01

    The current work relates to the development of synthetic calcium oxide (CaO) based compositions as candidate materials for energy storage under a cyclic carbonation/decarbonation reaction scheme. Although under such a cyclic scheme the energy density of natural lime based CaO is high (˜ 3MJ/kg), the particular materials suffer from notable cycle-to-cycle deactivation. To this direction, pure CaO and CaO/Al2O3 composites have been prepared and preliminarily evaluated under the suggested cyclic carbonation/decarbonation scheme in the temperature range of 600-800°C. For the composite materials, Ca/Al molar ratios were in the range between 95/5 and 52/48 and upon calcination the formation of mixed Ca/Al phases was verified. The preliminary evaluation of materials studied was conducted under 3 carbonation/decarbonation cycles and the loss of activity for the case of natural CaO was obvious. Synthetic materials with superior stability/capture c.f. natural CaO were further subjected to multi-cyclic carbonation/decarbonation, via which the positive effect of alumina addition was made evident. Selected compositions exhibited adequately high CO2 capture capacity and stable performance during multi-cyclic operation. Moreover, this study contains preliminary experiments referring to proof-of-principle validation of a concept based on the utilization of a CaO-based honeycomb reactor/heat exchanger preliminary design. In particular, cordierite monolithic structures were coated with natural CaO and in total 11 cycles were conducted. Upon operation, clear signs of heat dissipation by the imposed flow in the duration of the exothermic reaction step were identified.

  11. Mechanical and thermal-expansion characteristics of Ca10(PO46(OH2-Ca3(PO42 composites

    Directory of Open Access Journals (Sweden)

    Ruseska G.

    2006-01-01

    Full Text Available Three types of composites consisting of Ca10(PO46(OH2 and Ca3(PO42 with composition: 75% (wt Ca10(PO46(OH2: 25%(wt Ca3(PO42; 50%(wt Ca10(PO46(OH2: 50%(wtCa3(PO42 and 25 %(wt Ca10(PO46(OH2: 75%(wt Ca3(PO42 were the subject of our investigation. Sintered compacts were in thermal equilibrium, which was proved by the absence of hysteresis effect of the dependence ΔL/L=f(T during heating /cooling in the temperature interval 20-1000-200C. Sintered compacts with the previously mentioned composition possess 26-50% higher values of the E-modulus, G-modulus and K-modulus indicating the presence of a synergism effect. Several proposed model equations for predicting the thermal expansion coefficient in dependence of the thermal and elastic properties of the constitutive phases and their volume fractions, given by: Turner, Kerner, Tummala and Friedberg, Thomas and Taya, were used for making correlations between mechanical and thermal-expansion characteristics of the Ca10(PO46(OH2 - Ca3(PO42 composites. Application of the previously mentioned model equations to all kinds of composites leads to the conclusion that the experimentally obtained results for the thermal expansion coefficient are in an excellent agreement with the theoretical calculated values on account of the volume fraction of each constitutive phase and with all applied model equations, with a coefficient of correlation from 98.16-99.86 %.

  12. Midbrain dopamine neurons bidirectionally regulate CA3-CA1 synaptic drive.

    Science.gov (United States)

    Rosen, Zev B; Cheung, Stephanie; Siegelbaum, Steven A

    2015-12-01

    Dopamine (DA) is required for hippocampal-dependent memory and long-term potentiation (LTP) at CA1 Schaffer collateral (SC) synapses. It is therefore surprising that exogenously applied DA has little effect on SC synapses, but suppresses CA1 perforant path (PP) inputs. To examine DA actions under more physiological conditions, we used optogenetics to release DA from ventral tegmental area inputs to hippocampus. Unlike exogenous DA application, optogenetic release of DA caused a bidirectional, activity-dependent modulation of SC synapses, with no effect on PP inputs. Low levels of DA release, simulating tonic DA neuron firing, depressed the SC response through a D4 receptor-dependent enhancement of feedforward inhibition mediated by parvalbumin-expressing interneurons. Higher levels of DA release, simulating phasic firing, increased SC responses through a D1 receptor-dependent enhancement of excitatory transmission. Thus, tonic-phasic transitions in DA neuron firing in response to motivational demands may cause a modulatory switch from inhibition to enhancement of hippocampal information flow.

  13. Ca intercalated bilayer graphene as a thinnest limit of superconducting C6Ca.

    Science.gov (United States)

    Kanetani, Kohei; Sugawara, Katsuaki; Sato, Takafumi; Shimizu, Ryota; Iwaya, Katsuya; Hitosugi, Taro; Takahashi, Takashi

    2012-11-27

    Success in isolating a 2D graphene sheet from bulky graphite has triggered intensive studies of its physical properties as well as its application in devices. Graphite intercalation compounds (GICs) have provided a platform of exotic quantum phenomena such as superconductivity, but it is unclear whether such intercalation is feasible in the thinnest 2D limit (i.e., bilayer graphene). Here we report a unique experimental realization of 2D GIC, by fabricating calcium-intercalated bilayer graphene C(6)CaC(6) on silicon carbide. We have investigated the structure and electronic states by scanning tunneling microscopy and angle-resolved photoemission spectroscopy. We observed a free-electron-like interlayer band at the Brillouin-zone center, which is thought to be responsible for the superconductivity in 3D GICs, in addition to a large π* Fermi surface at the zone boundary. The present success in fabricating Ca-intercalated bilayer graphene would open a promising route to search for other 2D superconductors as well as to explore its application in devices.

  14. HIF-1α-mediated upregulation of SERCA2b: The endogenous mechanism for alleviating the ischemia-induced intracellular Ca(2+) store dysfunction in CA1 and CA3 hippocampal neurons.

    Science.gov (United States)

    Kopach, Olga; Maistrenko, Anastasiia; Lushnikova, Iryna; Belan, Pavel; Skibo, Galina; Voitenko, Nana

    2016-05-01

    Pyramidal neurons of the hippocampus possess differential susceptibility to the ischemia-induced damage with the highest vulnerability of CA1 and the lower sensitivity of CA3 neurons. This damage is triggered by Ca(2+)-dependent excitotoxicity and can result in a delayed cell death that might be potentially suspended through activation of endogenous neuroprotection with the hypoxia-inducible transcription factors (HIF). However, the molecular mechanisms of this neuroprotection remain poorly understood. Here we show that prolonged (30min) oxygen and glucose deprivation (OGD) in situ impairs intracellular Ca(2+) regulation in CA1 rather than in CA3 neurons with the differently altered expression of genes coding Ca(2+)-ATPases: the mRNA level of plasmalemmal Ca(2+)-ATPases (PMCA1 and PMCA2 subtypes) was downregulated in CA1 neurons, whereas the mRNA level of the endoplasmic reticulum Ca(2+)-ATPases (SERCA2b subtype) was increased in CA3 neurons at 4h of re-oxygenation after prolonged OGD. These demonstrate distinct susceptibility of CA1 and CA3 neurons to the ischemic impairments in intracellular Ca(2+) regulation and Ca(2+)-ATPase expression. Stabilization of HIF-1α by inhibiting HIF-1α hydroxylation prevented the ischemic decrease in both PMCA1 and PMCA2 mRNAs in CA1 neurons, upregulated the SERCA2b mRNA level and eliminated the OGD-induced Ca(2+) store dysfunction in these neurons. Cumulatively, these findings reveal the previously unknown HIF-1α-driven upregulation of Ca(2+)-ATPases as a mechanism opposing the ischemic impairments in intracellular Ca(2+) regulation in hippocampal neurons. The ability of HIF-1α to modulate expression of genes coding Ca(2+)-ATPases suggests SERCA2b as a novel target for HIF-1 and may provide potential implications for HIF-1α-stabilizing strategy in activating endogenous neuroprotection.

  15. Rice-like hollow nano-CaCO3 synthesis

    Science.gov (United States)

    Ulkeryildiz, Eda; Kilic, Sevgi; Ozdemir, Ekrem

    2016-09-01

    We have shown that Ca(OH)2 solution is a natural stabilizer for CaCO3 particles. We designed a CO2 bubbling crystallization reactor to produce nano-CaCO3 particles in homogenous size distribution without aggregation. In the experimental set-up, the crystallization region was separated from the stabilization region. The produced nanoparticles were removed from the crystallization region into the stabilization region before aggregation or crystal growth. It was shown that rice-like hollow nano-CaCO3 particles in about 250 nm in size were produced with almost monodispersed size distribution. The particles started to dissolve through their edges as CO2 bubbles were injected, which opened-up the pores inside the particles. At the late stages of crystallization, the open pores were closed as a result of dissolution-recrystallization of the newly synthesized CaCO3 particles. These particles were stable in Ca(OH)2 solution and no aggregation was detected. The present methodology can be used in drug encapsulation into inorganic CaCO3 particles for cancer treatment with some modifications.

  16. Fabrication and characterization of CaP-coated nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Kung, Kuan-Chen; Chen, Jia-Ling [Institute of Oral Medicine, National Cheng Kung University, Tainan 701, Taiwan (China); Liu, Yen-Ting [Department of Materials Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Lee, Tzer-Min, E-mail: tmlee@mail.ncku.edu.tw [Institute of Oral Medicine, National Cheng Kung University, Tainan 701, Taiwan (China); Medical Device Innovation Center, National Cheng Kung University, Tainan 701, Taiwan (China); School of Dentistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China)

    2015-03-01

    Modified anodization techniques have been shown to improve the biocompatibility of titanium. This study demonstrated the anodic formation of self-organized nanotube arrays on titanium from an electrolyte solution containing 1 M H{sub 3}PO{sub 4} and 1 wt% hydrofluoric acid (HF). Our aim was to investigate the effects of sputter-deposited CaP on nanotube arrays. SEM images revealed a surface with uniform morphology and an average pore diameter of 29 nm. XRD results indicated that the phase of the nanotube arrays was amorphous. Electron spectroscopy for chemical analysis (ESCA) confirmed that the nanotube arrays were coated with calcium and phosphorus. Cell culture experiments using human osteosarcoma (HOS) cells demonstrated that the CaP/nanotube arrays had a pronounced effect on initial cell attachment as well as on the number of cells at 1, 7, and 14 days. Compared to as-polished titanium, the CaP/nanotube arrays accelerated cell proliferation, attachment, and spreading. Our results demonstrate the pronounced effects of CaP/nanotube arrays on the biological responses of HOS cells. - Highlights: • Self-organized nanotube arrays were anodically formed on titanium. • Surfaces of nanotube arrays exhibited uniform morphology and pore size. • According to ESCA results, Ca and P were successfully coated on nanotube arrays. • CaP/nanotube arrays accelerated the attachment and spreading of cells. • CaP/nanotube arrays were shown to affect biological responses of cells.

  17. Decoding Dynamic Ca2+ Signaling in the Vascular Endothelium

    Directory of Open Access Journals (Sweden)

    Mark Stephen Taylor

    2014-11-01

    Full Text Available Although acute and chronic vasoregulation is inherently driven by endothelial Ca2+, control and targeting of Ca2+-dependent signals are poorly understood. Recent studies have revealed localized and dynamic endothelial Ca2+ events comprising an intricate signaling network along the vascular intima. Discrete Ca2+ transients emerging from both internal stores and plasmalemmal cation channels couple to specific membrane K+ channels, promoting endothelial hyperpolarization and vasodilation. The spatiotemporal tuning of these signals, rather than global Ca2+ elevation, appear to direct endothelial functions under physiologic conditions. In fact, altered patterns of dynamic Ca2+ signaling may underlie essential endothelial dysfunction in a variety of cardiovascular diseases. Advances in imaging approaches and analyses in recent years have allowed for detailed detection, quantification, and evaluation of Ca2+ dynamics in intact endothelium. Here, we discuss recent insights into these signals, including their sources of origination and their functional encoding. We also address key aspects of data acquisition and interpretation, including broad applications of automated high-content analysis.

  18. A Constrained CA Model for Planning Simulation Incorporating Institutional Constraints

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In recent years,it is prevailing to simulate urban growth by means of cellular automata (CA in short) modeling,which is based on selforganizing theories and different from the system dynamic modeling.Since the urban system is definitely complex,the CA models applied in urban growth simulation should take into consideration not only the neighborhood influence,but also other factors influencing urban development.We bring forward the term of complex constrained CA (CC-CA in short) model,which integrates the constrained conditions of neighborhood,macro socio-economy,space and institution.Particularly,the constrained construction zoning,as one institutional constraint,is considered in the CC-CA modeling.In the paper,the conceptual CC-CA model is introduced together with the transition rules.Based on the CC-CA model for Beijing,we discuss the complex constraints to the urban development of,and we show how to set institutional constraints in planning scenario to control the urban growth pattern of Beijing.

  19. Changes to a CA Programme - Practitioners' Perspectives

    Directory of Open Access Journals (Sweden)

    Elizabeth Wheeler

    2014-03-01

    Full Text Available This paper examines the perceptions of practitioners of the new directions taken by NZICA with respect to its academic and professional programme requirements to obtain CA Institute membership. The “future viability of any professional body is dependent on continuously attracting new members, ideally the best and the brightest new tertiary graduates”, and this is “undoubtedly the case for New Zealand’s professional accounting body, the New Zealand Institute of Chartered Accountants (NZICA” (Malthus & Fowler 2009, p. 26. In this study, the concurrent triangulation approach to mixed methods described by Creswell (2009 was used to collect data. This approach enabled the results of the two quantitative and qualitative databases to be integrated and compared. It was found that accounting practitioners felt the changes made by NZICA may devalue the brand, while the reduction in liberal papers would result in a narrower degree. Overall, accounting practitioners agreed that three to four years of tertiary accounting education was adequate, a broader four-year course would result in a better-rounded graduates. The reduction in the length of the tertiary programme caused concern that future graduates would be less mature. Accounting practitioners also felt that the changes would harm the credibility of NZICA internationally. However, some accounting practitioners did welcome the fact that the NZICA membership requirements will be more aligned with Institute of Chartered Accountants Australia. Accounting practitioners felt that the new technical modules would offer more flexibility. They believed that the four technical modules should repeat the material taught at university, as long as a balance was maintained between technical and practical skills. They also believed that the changes would result in an increased onus on the employer. Additionally, accounting practitioners agreed that on-the-job training should not replace a tertiary

  20. Computer Simulation for Effect of Tb3+ on Ca2+Speciation in Human Plasma

    Institute of Scientific and Technical Information of China (English)

    卢兴; 王悦; 张海元; 王进平; 牛春吉; 倪嘉缵

    2002-01-01

    Effect of Tb3+ on Ca2+ speciation in human plasma was studied by means of the computer program of MINTEQA2. When Tb3+ ions are not added into the system, Ca2+ ions mostly distribute in free Ca2+ (74.7%) and the surplus distributes in Ca2+ complexes, such as [CaHCO3]+(7.9%), [Ca(Lac)]+(6.4%), CaHPO4 (1.3%), [CaHistidinateThreoninateH3]3+(2.4%), [CaCitrateHistidinateH2] (2.3%) and CaCO3(1.1%). Tb3+ can compete with Ca2+ for inorganic as well as biological ligands. An increase of concentration of Tb3+ in the system results in an increase of content of free Ca2+ and a decrease of contents of Ca2+ complexes.

  1. Menstrual Cycle Dependent Variability for Serum Tumor Markers CEA, AFP, CA 19-9, CA 125 and CA 15-3 in Healthy Women

    Directory of Open Access Journals (Sweden)

    Ayşe Binnur Erbağci

    1999-01-01

    Full Text Available Information on menstrual cycle dependent variation of tumor markers in healthy women is a subject of diagnostic efficiency and has an impact in elucidating the normal function of these markers. In this study midfollicular and midluteal concentrations of serum CEA, AFP, CA 19-9, CA 125, CA 15-3 and their relations with LH, FSH, prolactin, estradiol and progesterone were evaluated during ovulatory cycles in a group of 23 healthy female individuals. Samples were collected on the 7th and 21st day of the same menstrual cycle. Tumor marker and hormone concentrations were determined with chemiluminescence or electrochemiluminescence EIA methods. A significant phase-dependent difference was observed for CA 15-3, midluteal concentrations (mean ± SEM; 26.33 ± 1.56 U/ml higher than the midfollicular (mean ± SEM; 19.27 ± 1.49 U/ml concentrations (p < 0.001. But an obvious difference for other tumor markers investigated did not exist. Significant correlations of follicular and luteal CA 125 levels with body mass index of the subjects were observed (r:0.52, p < 0.05 and r:0.57, p < 0.005, respectively.

  2. IR laser operated piezooptics in PbTe:Ca crystals

    CERN Document Server

    Roknabad, Mahmoud Rezaee; Razavi, Mohammad; Mollai, Maedeh

    2013-01-01

    IR induced piezo optic effect (POE) in PbTe:Ca crystals was found under the influence of nanosecond pulse CO2 laser with a wavelength of 10.6 micro meters. It was shown that addition of Ca leads to an increase of the POE tensor coefficient. This indicates the appearance of enhanced IR induced static dipole moments caused predominately by Ca impurities. Simultaneously, the variations in time kinetics for the POE in nanosecond time regime were explored. A substantial role of electron phonon subsystem in the observed POE effect was demonstrated. The studies were done both for diagonal as well as off diagonal POE tensor components.

  3. Effects of short range correlations on Ca isotopes

    CERN Document Server

    Lalazissis, G A

    1996-01-01

    The effect of Short Range Correlations (SRC) on Ca isotopes is studied using a simple phenomenological model. Theoretical expressions for the charge (proton) form factors, densities and moments of Ca nuclei are derived. The role of SRC in reproducing the empirical data for the charge density differences is examined. Their influence on the depletion of the nuclear Fermi surface is studied and the fractional occupation probabilities of the shell model orbits of Ca nuclei are calculated. The variation of SRC as function of the mass number is also discussed.

  4. Spectral components of cytosolic [Ca2+] spiking in neurons

    DEFF Research Database (Denmark)

    Kardos, J; Szilágyi, N; Juhász, G;

    1998-01-01

    into evolutionary spectra of a characteristic set of frequencies. Non-delayed small spikes on top of sustained [Ca2+]c were synthesized by a main component frequency, 0.132+/-0.012 Hz, showing its maximal amplitude in phase with the start of depolarization (25 mM KCI) combined with caffeine (10 mM) application....... Delayed complex responses of large [Ca2+]c spiking observed in cells from a different set of cultures were synthesized by a set of frequencies within the range 0.018-0.117 Hz. Differential frequency patterns are suggested as characteristics of the [Ca2+]c spiking responses of neurons under different...

  5. Efimov physics around the neutron-rich 60Ca isotope.

    Science.gov (United States)

    Hagen, G; Hagen, P; Hammer, H-W; Platter, L

    2013-09-27

    We calculate the neutron-60Ca S-wave scattering phase shifts using state of the art coupled-cluster theory combined with modern ab initio interactions derived from chiral effective theory. Effects of three-nucleon forces are included schematically as density dependent nucleon-nucleon interactions. This information is combined with halo effective field theory in order to investigate the 60Ca-neutron-neutron system. We predict correlations between different three-body observables and the two-neutron separation energy of 62Ca. This provides evidence of Efimov physics along the calcium isotope chain. Experimental key observables that facilitate a test of our findings are discussed.

  6. Coping with Asymmetric Channel Losses in CSMA/CA

    DEFF Research Database (Denmark)

    Paramanathan, Achuthan; Roetter, Daniel Enrique Lucani; Fitzek, Frank

    2013-01-01

    Inspired by the discrepancy between past theoretical analysis and real measurements for high-load scenarios for intersession network coding, we pinpoint and analyze the source of this discrepancy in wireless networks implementing a CSMA/CA medium access scheme. Our analysis shows that CSMA/CA is ......) confirm the sensitivity of the CSMA/CA scheme in real implementations, and (ii) shows that our adaptive protocol provides a simple, yet potent mechanism to cope with asymmetric channel losses and ultimately to enhance end-to-end throughput in high-load scenarios....

  7. Neuromodulation of the feedforward dentate gyrus-CA3 microcircuit

    Directory of Open Access Journals (Sweden)

    Luke Yuri Prince

    2016-10-01

    Full Text Available The feedforward dentate gyrus-CA3 microcircuit in the hippocampus is thought to activate ensembles of CA3 pyramidal cells and interneurons to encode and retrieve episodic memories. The creation of these CA3 ensembles depends on neuromodulatory input and synaptic plasticity within this microcircuit. Here we review the mechanisms by which the neuromodulators aceylcholine, noradrenaline, dopamine, and serotonin reconfigure this microcircuit and thereby infer the net effect of these modulators on the processes of episodic memory encoding and retrieval.

  8. Preparation,Isolation and Characterization of Ca@C88 and Ca@C90%Ca@C88和Ca@C90的合成、分离和表征

    Institute of Scientific and Technical Information of China (English)

    张娅; 施祖进; 郝策; 徐建勋; 贺晓然; 顾镇南

    2004-01-01

    利用直流电弧法,合成了含钙的富勒烯金属包合物.通过多步高效液相色谱(HPLC)法,首次分离出含钙的富勒烯金属包合物Ca@Ca8和Ca@C90(Ⅰ,Ⅱ),用激光解析飞行时间质谱(MAL-DI-TOFMS)和紫外-可见-近红外(UV-Vis-NIR)光谱进行了表征,并对其分子对称性和电子结构进行了讨论.

  9. Effects of Ca additions on some Mg-alloy hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Lupu, D.; Biris, A.; Indrea, E.; Bucur, R.V.

    1983-01-01

    The hydrogenation of the alloy of composition CaMg/sub 1/ /sub 8/Ni/sub 0/ /sub 5/ containing CaMg/sub 2/ and MgNi/sub 2/ shows fast activation kinetics. The Mg/sub 2/Ni phase is observed in the dehydrided samples. The three plateaus on the hydrogen desorption isotherms correspond to the most stable magnesium hydrides observed up to now in Mg-alloy (..delta.. H = 20 to 24 kcal/mol H/sub 2/). The effects of Ca additions on the hydrogen storage capacity and desorption rates of some Mg-rich alloys have been studied. 16 references, 3 figures, 1 table.

  10. Systematic B-metal substitution in CaNi5

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Bjerrum, Niels

    1999-01-01

    The aim of this work has been to study the effect of B metal substitutions in CaNi5 (AB(5)) which is known to suffer from poor cycling stability as a hydride electrode material. Systematic monosubstitutions of nickel with the most common other B metals (i.e. Al, Cr, Mn, Fe, Co, Cu, Zn and Sn...... be concluded that CaNi5 is much less tolerant towards B-metal substitution than LaNi5. This fact makes it less possible that the problem with cycling stability of Ca-based hydride electrodes can be solved by substitutions. (C) 1999 Elsevier Science S.A. All rights reserved....

  11. Delta(9)-tetrahydrocannabinol activates [Ca2+], increases partly sensitive to capacitative store refilling

    NARCIS (Netherlands)

    Filipeanu, CM; deZeeuw, D; Nelemans, SA

    1997-01-01

    Delta(9)-Tetrahydrocannabinol induces [Ca2+](i) increases in DDT1MF-2 smooth muscle cells. Both Ca2+ entry and release from intracellular Ca2+ stores were concentration dependently activated. The Ca2+ entry component contributed most to the increases in [Ca2+](i). Stimulation with Delta(9)-tetrahydr

  12. Glucose-induced Ca2 + signals in rat pancreatic β cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using microfluorometry to assay intracellular Ca2+ , the influences of varied factors on glucose induced Ca22+ signals, such as glucose-induced initial decline phase (GIDP), Ca2+ oscillation, and Ca2+ release from internal stores, were investigated in single rat pancreatic β cells. Glucose was able to evoke GIDP even at non-stimulus concentration (5 mol/L), which is insufficient to induce Ca2+ spikes. GIDP was dependent on neither membrane depo larization nor extraeellular Ca2+ . However, GIDP was inhibited by thapsigargin, indicating a dependence on Ca2+ up take by Ca22+ stores. The glucose-induced calcium oscillation was inhibited when external Ca2+ was removed. However, thapsigargin could not block the Ca2+ oscillation. These results suggest that maintenance of Ca22+ oscillation requires ex tracellular Ca2+ but not Ca2+ stores. Glucose was able to evoke Ca2+ signals even in the absence of external Ca2+ . The glucose-induced Ca2+ release from intracellular Ca2+ stores was blocked by TTX. However, TTX had no effect on high K--induced Ca2+ store release, suggesting that membrane depolarization can directly release Ca2+ from some internal Ca2+ stores in β cells.

  13. Retracing diagenetic processes in marine porewaters using Ca isotopes

    Science.gov (United States)

    Ockert, C.; Teichert, B. M.; Kaufhold, S.; Gussone, N. C.

    2012-12-01

    Calcium (Ca) isotope ratios of marine organic and inorganic mineral precipitates are used to monitor changes in the oceanic Ca-budget and in paleo-temperature, and serve as a proxy for the trophic level of organisms in the food chain (c.f. Skulan et al., 1997; Zhu et al., 1998). However, during interaction between sediments and porewater, the Ca isotopic composition of marine porewaters might be shifted, bearing the potential to alter the Ca isotope proxy records. While processes, such as partial dissolution of calcareous shells and carbonate recrystallization have been studied (Fantle and DePaolo, 2007; Turchyn and DePaolo 2011), other diagenetic processes such as ion exchange with clay minerals have not been taken into account while studying Ca isotope profiles of porewaters. Nevertheless, first experiments and the investigation of natural porewaters indicate that this process has a significant effect on the Ca isotope composition in marine porewaters. Laboratory experiments aimed to determine if Ca isotope fractionation occurs during Ca adsorption and exchange with ammonium on clay minerals. The results show that Ca adsorption in a seawater environment is associated with fractionation, where light Ca is preferably adorbed. The addition of ammonium to the experimental set up caused partial release of Ca accompanied by isotope fractionation. Based on the results of the experiments, model calculations tested the impact of varying clay mineral type, content and sediment porosity, revealing that ion exchange processes with clay minerals predominantly shift the porewater signal to lighter values. This is in agreement with observations by Teichert et al. (2009), who found a correlation of ammonium-concentration and δ44/40Ca ratios in the porewater of drill core samples from the Cascadia accretionary margin (ODP Leg 204). Calcium isotope ratios of natural marine porewaters of three sites in the North Atlantic (IODP Expedition 303) show that the correlation between

  14. A study of the dissociative recombination of CaO+ with electrons: Implications for Ca chemistry in the upper atmosphere

    Science.gov (United States)

    Bones, D. L.; Gerding, M.; Höffner, J.; Martín, Juan Carlos Gómez; Plane, J. M. C.

    2016-12-01

    The dissociative recombination of CaO+ ions with electrons has been studied in a flowing afterglow reactor. CaO+ was generated by the pulsed laser ablation of a Ca target, followed by entrainment in an Ar+ ion/electron plasma. A kinetic model describing the gas-phase chemistry and diffusion to the reactor walls was fitted to the experimental data, yielding a rate coefficient of (3.0 ± 1.0) × 10-7 cm3 molecule-1 s-1 at 295 K. This result has two atmospheric implications. First, the surprising observation that the Ca+/Fe+ ratio is 8 times larger than Ca/Fe between 90 and 100 km in the atmosphere can now be explained quantitatively by the known ion-molecule chemistry of these two metals. Second, the rate of neutralization of Ca+ ions in a descending sporadic E layer is fast enough to explain the often explosive growth of sporadic neutral Ca layers.

  15. Comparison between tissue and serum content of CA 125, CA 19-9, and carcinoembryonic antigen in ovarian tumors.

    Science.gov (United States)

    Breitenecker, G; Neunteufel, W; Bieglmayer, C; Kölbl, H; Schieder, K

    1989-01-01

    Tumor markers CA 125, CA 19-9, and carcinoembryonic antigen (CEA) were detected by immunohistochemistry in paraffin embedded tissue samples obtained from two different locations in 35 ovarian tumors. In addition, serum concentrations of these tumor markers were measured before cytoreductive surgery. The staining reaction was heterogeneous in different parts of the tumor as well as within the parenchyma. Of the marker positive tumors, a staining reaction was observed in both tissue samples in only 10 of 22 cases for CA 125, in eight of 13 cases for CEA, and in three of eight cases for CA 19-9. Eighty-one percent of the patients whose tumor was positive for CA 125 also showed elevated serum levels of this marker. A poor correlation was found between tissue and circulating CA 19-9 levels. CEA was detected in 28% of the tumors and seemed to be valuable only for monitoring in rare cases of ovarian cancer. For purposes of selecting a marker for monitoring of patients with ovarian carcinoma, immunohistochemistry has a predictive value for CA 125 only. In order to better define the marker expressed in a tumor, it is necessary to examine at least two samples of different parts of the malignant tissue.

  16. Diagnostic value of joint detection of serum CA1 9-9,CA125 and CA242 for cholangiocarci-noma%血清 CA 19-9、CA 125、CA242联合检测对胆管癌诊断价值的评价

    Institute of Scientific and Technical Information of China (English)

    崔大鹏; 韩磊; 刘振显; 杨贺; 张迎春

    2016-01-01

    Objective:To study the diagnostic value of joint detection of serum CA1 9-9,CA125 and CA242 for cholan-giocarcinoma.Methods:A total of 35 patients with cholangiocarcinoma who received surgical resection in our hospital were se-lected as malignant group;30 patients with cholelithiasis who received surgical resection in our hospital during the same period were selected as benign group.Serum samples were collected before surgery to determine CA1 9-9,CA125 and CA242 content;and cholangiocarcinoma tissue and normal bile duct tissue were collected after surgery to determine the content of proliferation and invasion molecules.Results:Serum CA1 9-9,CA125 and CA242 levels of malignant group were significantly higher than those of control group (P <0.05);PROX-1,Ki-67,Bcl-2,Bad,Gab1,LOXL2,TRPM7 and CXCL12 levels in cholangiocar-cinoma tissue were significantly higher than those in benign bile duct tissue (P <0.05);and E-cadherin level was significantly lower than that in benign bile duct tissue (P <0.05);serum CA1 9-9,CA125 and CA242 levels were positively correlated with PROX-1,Ki-67,Bcl-2,Bad,Gab1,LOXL2,TRPM7 and CXCL12 levels,and negatively correlated with E-cadherin level. Conclusions:Joint detection of serum CA1 9-9,CA125 and CA242 can not only provide reference for the diagnosis of cholangio-carcinoma,but also can provide basis for the evaluation of proliferation,invasion and other malignant biological behaviors.%目的::研究血清 CA19-9、CA125、CA242联合检测对胆管癌的诊断价值.方法:选择在我院接受手术切除的35例胆管癌患者作为恶性组,同期在我院接受手术切除的30例胆石症患者作为良性组,术前采集血清标本并测定 CA19-9、CA125、CA242含量,术后采集胆管癌组织和正常胆管组织并测定增殖、侵袭分子的含量.结果:恶性组血清中 CA19-9、CA125、CA242的含量显著高于对照组(P <0.05);胆管癌组织中 PROX-1、Ki-67、Bcl-2、Bad、Gab1、LOXL2、TRPM7、CXCL12

  17. MgO-CaO耐火材料性能研究进展%Research progress of MgO-CaO refractory

    Institute of Scientific and Technical Information of China (English)

    王宏联; 崔庆阳; 薛群虎

    2010-01-01

    介绍了MgO-CaO耐火材料的特性.总结了提高MgO-CaO耐火材料的抗水化性、烧结性、抗渣性、抗剥落性等的技术措施.提出了 MgO-CaO耐火材料的发展方向,即:开发高CaO含量的MgO-CaO耐火材料;进一步开发不烧MgO-CaO耐火材料;开发水泥回转窑再MgO-CaO耐火材料.

  18. Modeling sharp wave-ripple complexes through a CA3-CA1 network model with chemical synapses.

    Science.gov (United States)

    Taxidis, Jiannis; Coombes, Stephen; Mason, Robert; Owen, Markus R

    2012-05-01

    The hippocampus, and particularly the CA3 and CA1 areas, exhibit a variety of oscillatory rhythms that span frequencies from the slow theta range (4-10 Hz) up to fast ripples (200 Hz). Various computational models of different complexities have been developed in an effort to simulate such population oscillations. Nevertheless the mechanism that underlies the so called Sharp Wave-Ripple complex (SPWR), observed in extracellular recordings in CA1, still remains elusive. We present here, the combination of two simple but realistic models of the rat CA3 and CA1 areas, connected together in a feedforward scheme mimicking Schaffer collaterals. Both network models are computationally simple one-dimensional arrays of excitatory and inhibitory populations interacting only via fast chemical synapses. Connectivity schemes and postsynaptic potentials are based on physiological data, yielding a realistic network topology. The CA3 model exhibits quasi-synchronous population bursts, which give rise to sharp wave-like deep depolarizations in the CA1 dendritic layer accompanied by transient field oscillations at ≈ 150-200 Hz in the somatic layer. The frequency and synchrony of these oscillations is based on interneuronal activity and fast-decaying recurrent inhibition in CA1. Pyramidal cell spikes are sparse and come from a subset of cells receiving stronger than average excitatory input from CA3. The model is shown to accurately reproduce a large number of basic characteristics of SPWRs and yields a new mechanism for the generation of ripples, offering an interpretation to a range of neurophysiological observations, such as the ripple disruption by halothane and the selective firing of pyramidal cells during ripples, which may have implications for memory consolidation during SPWRs.

  19. Evolution of precipitation during non-isothermal ageing of an Mg-Ca-Zn alloy with high Ca content

    Energy Technology Data Exchange (ETDEWEB)

    Langelier, Brian, E-mail: blangeli@engmail.uwaterloo.ca [University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1 (Canada); Wang, Xiang [McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L8 (Canada); Esmaeili, Shahrzad [University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1 (Canada)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Precipitation hardening characterized for an Mg-Ca-Zn alloy with high Ca content. Black-Right-Pointing-Pointer Evolution of precipitation during non-isothermal ageing identified by TEM and DSC. Black-Right-Pointing-Pointer DSC data de-convoluted using heat treatments developed from thermodynamic analysis. Black-Right-Pointing-Pointer De-convoluted DSC provides further insight into the complex precipitation behaviour. - Abstract: In this work, the precipitation behaviour of an Mg-Ca-Zn alloy with high content of Ca relative to Zn was studied. Differential scanning calorimetry (DSC) was combined with transmission electron microscopy (TEM) and hardness measurement to examine the precipitate evolution in this alloy. A non-isothermal age-hardening heat treatment was performed to allow for a direct comparison to DSC results. Thermodynamic analysis aided in identifying ageing heat treatments to further de-convolute the overlapping DSC data. Results suggested the precipitation events followed sequential evolution towards the formation of two types of equilibrium phases (i.e. Mg{sub 2}Ca and Mg{sub 6}Ca{sub 2}Zn{sub 3}). Early stage decomposition of the solid solution had no observable effect on hardness, but was followed by the formation of hardening GP zones. Fine basal plates, as well as large coarse basal plates of Mg{sub 2}Ca-type formed on further ageing. Contrast due to fine unidentified nanoscale precipitates was also observed in the over-aged state. These precipitates tended to disappear, while blocky Mg{sub 2}Ca equilibrium phase precipitates formed as the heat treatment progressed to the highest temperature studied (i.e. 300 Degree-Sign C). However, the equilibrium Mg{sub 6}Ca{sub 2}Zn{sub 3}phase was not observed when this final test temperature was achieved at the end of the non-isothermal heat treatment process.

  20. The effect of external Ca2+ and Ca2+—channel modulators on red—light—induced swelling of protoplasts of Phaseolus radiatus L.

    Institute of Scientific and Technical Information of China (English)

    LONGCHENG; XIAOJINGWANG; 等

    1998-01-01

    Red-light-induced swelling of the protoplasts isolated from hypocotyl of etiolated mung bean(Phaseolus radiatusL.)was observed only when Ca2+ ions were present in the medium.The optimal CaCl2 concentration was 250μM,Swlling response declined when Ca2+ was supplied into the medium after red light irradiation.The Ca2+-chelator EGTA eliminated the red-light-induced swelling and 45Ca2+ accumulation in the protoplasts.In conltrast,A23187,a Ca2+-ionophore,could mimic the effect of red light in darkness.These results indicate that Ca2+ may play a role in light signal transduction.In addition,swelling response was prevented by TFP and CPZ(both are CaM antagonists),implying the involvement of CaM in red-light-induced and Ca2+ -dependent protoplast swelling.

  1. Temperature and Ca2+-dependence of the sarcoplasmic reticulum Ca2(+)-ATPase in haddock, salmon, rainbow trout and zebra cichlid

    DEFF Research Database (Denmark)

    Godiksen, Helene; Jessen, Flemming

    2002-01-01

    in the enzyme or its membrane lipid environment is still a matter of discussion. In this study we compared the temperature dependence and Ca2+-dependence of SR Ca2+-ATPase in haddock (Melanogrammus aeglefinus), salmon (Salmo, salar), rainbow trout (Oncorhynchus mykiss) and zebra cichlid (Cichlasoma...... nigrofasciatum). The Arrhenius plot of zebra cichlid showed a break point at 20 degreesC, and the haddock Arrhenius plot was non-linear with pronounced changes in slope in the. temperature area, 6-14 degreesC. In Arrhenius plot from both salmon and rainbow trout a plateau exists with an almost constant SR Ca2...

  2. Anandamide reduces intracellular Ca2+ concentration through suppression of Na+/Ca2+ exchanger current in rat cardiac myocytes.

    Directory of Open Access Journals (Sweden)

    Qian Li

    Full Text Available PURPOSE: Anandamide, one of the endocannabinoids, has been reported to exhibit cardioprotective properties, particularly in its ability to limit the damage produced by ischemia reperfusion injury. However, the mechanisms underlying the effect are not well known. This study is to investigate whether anandamide alter Na(+/Ca(2+ exchanger and the intracellular free Ca(2+ concentration ([Ca(2+]i. METHODS: Na(+/Ca(2+ exchanger current (I(NCX was recorded and analysed by using whole-cell patch-clamp technique and [Ca(2+]i was measured by loading myocytes with the fluorescent Ca(2+ indicator Fura-2/AM. RESULTS: We found that I(NCX was enhanced significantly after perfusion with simulated ischemic external solution; [Ca(2+]i was also significantly increased by simulated ischemic solution. The reversal potential of I(NCX was shifted to negative potentials in simulated ischemic external solution. Anandamide (1-100 nM failed to affect I(NCX and [Ca(2+]i in normal solution. However, anandamide (1-100 nM suppressed the increase in INCX in simulated ischemic external solution concentration-dependently and normalized INCX reversal potential. Furthermore, anandamide (100 nM significantly attenuated the increase in [Ca(2+]i in simulated ischemic solution. Blocking CB1 receptors with the specific antagonist AM251 (500 nM failed to affect the effects of anandamide on I(NCX and [Ca(2+]i in simulated ischemic solution. CB2 receptor antagonist AM630 (100 nM eliminated the effects of anandamide on I(NCX and [Ca(2+]i in simulated ischemic solution, and CB2 receptor agonist JWH133 (100 nM simulated the effects of anandamide that suppressed the increase in I(NCX and [Ca(2+]i in simulated ischemic solution. In addition, pretreatment with the Gi/o-specific inhibitor pertussis toxin (PTX, 500 ng/ml eliminated the effects of anandamide and JWH133 on I(NCX in simulated ischemic solution. CONCLUSIONS: Collectively, these findings suggest that anandamide suppresses calcium

  3. Engineering multiferroism in CaMnO3.

    Science.gov (United States)

    Bhattacharjee, Satadeep; Bousquet, Eric; Ghosez, Philippe

    2009-03-20

    Structural instabilities of CaMnO3 are investigated from first principles. We point out that, on top of a strong antiferrodistortive instability responsible for its orthorhombic ground state, the cubic perovskite structure of CaMnO3 also exhibits a weak ferroelectric instability. Although ferroelectricity is suppressed by antiferrodistortive motions, we show that it can be favored using strain or chemical engineering in order to make CaMnO3 multiferroic. We finally highlight that the ferroelectric instability of CaMnO3 is Mn-dominated. This illustrates that, contrary to common belief, ferroelectricity and magnetism are not necessarily exclusive but can be driven by the same cation.

  4. The luminescence of titanite (CaTiSiO5)

    NARCIS (Netherlands)

    Blasse, G.; Dirksen, G.J.; Tanaka, I.; Kojima, H.

    1988-01-01

    The luminescence of CaTiSiO5 crystals is reported. The emission band has its maximum at 520 nm. The results are discussed in connection with titanium compounds containing comparable titanate polyhedra.

  5. Neuronal migration and its disorders affecting the CA3 region

    Directory of Open Access Journals (Sweden)

    Richard eBelvindrah

    2014-03-01

    Full Text Available In this review, we focus on CA3 neuronal migration disorders in the rodent. We begin by introducing the main steps of hippocampal development, and we summarize characteristic hippocampal malformations in human. We then describe various mouse mutants showing structural hippocampal defects. Notably, genes identified in human cortical neuronal migration disorders consistently give rise to a CA3 phenotype when mutated in the mouse. We successively describe their molecular, physiological and behavioral phenotypes that together contribute to a better understanding of CA3-dependent functions. We finally discuss potential factors underlying the CA3 vulnerability revealed by these mouse mutants and that may also contribute to other human neurological and psychiatric disorders.

  6. Mixing Corrosion of CaCO3 in Natural Waters

    Directory of Open Access Journals (Sweden)

    Qian Hui

    2011-01-01

    Full Text Available The methods of aqueous speciation calculation, pH calculation and the solubility (precipitability calculation of CaCO3 were used to study the mixing corrosion of CaCO3 in natural waters. Mixing processes were done between two unsaturated (with CaCO3 solutions, two oversaturated solutions and between an unsaturated solution and an oversaturated solution, respectively. Results show that the mixing corrosion can be divided into two different levels: mixing corrosion in strict sense and mixing corrosion in broad sense. When mixing corrosion occurs, the HCO3- concentration in one end member solution is usually higher than that in the other solution, and the Ca2+ concentration in the former solution is also usually higher than that in the latter one.

  7. The Raman spectrum of monetite, CaHPO 4

    Science.gov (United States)

    Casciani, F.; Condrate, R. A.

    1980-10-01

    The Raman spectrum was measured for monetite, CaHPO 4. A consistent set of band assignments were made for both the Raman and infrared spectra. The effects of factor group and two-site effect are discussed.

  8. Towards an AC-MOT of CaF

    Science.gov (United States)

    Anderegg, Loic; Chae, Eunmi; Ravi, Aakash; Augenbraun, Benjamin; Hemmerling, Boerge; Drayna, Garrett; Hutzler, Nicholas; Collopy, Alejandra; Wu, Yewei; Ding, Shiqian; Ye, Jun; Ketterle, Wolfgang; Doyle, John

    2016-05-01

    Ultra-cold diatomic molecules have rich prospects as candidates to study controlled ultra-cold chemistry, strongly correlated systems and precision measurements. They are also considered as possible qubits in quantum computing and simulation schemes. We report on progress towards loading CaF into a molecular magneto-optical trap (MOT). An AC-MOT will be used to actively remix magnetic dark states via both polarization and magnetic field switching. In order to load a molecular MOT, we have successfully laser slowed a CaF beam to near the expected capture velocity. We describe our AC-MOT apparatus, which is designed to co-trap CaF and Li. We outline our planned study of CaF-Li collisions to explore the feasibility of sympathetically cooling molecules to ultra-cold temperatures.

  9. FCCP modulation of Ca2+ oscillation in rat megakaryocytes.

    Science.gov (United States)

    Uneyama, C; Uneyama, H; Takahashi, M; Akaike, N

    1994-08-16

    The effects of a mitochondrial uncoupler, FCCP, (carbonyl cyanide-p-trifluromethoxyphenyl-hydrazone) on the regulation of cytoplasmic Ca2+ were investigated in ATP-induced Ca2+ oscillation system of rat megakaryocyte. Application of FCCP did not induce any detectable Ca(2+)-activated K+ current (IKCa) but pretreatment with FCCP modulated the ATP-induced repetitive IKCa. FCCP abolished the IKCa induced by low concentrations of ATP. However, when the concentration of ATP was high, the uncoupler also changed the periodic current to a sustained one. Similar biphasic regulation by the uncoupler was observed in the case of IP3-evoked repetitive IKCa. These results indicate that FCCP inhibits both Ca2+ mobilization and elimination processes after IP3 liberation induced by agonist stimulation.

  10. TEM observation on nucleation of Ca a-Sialon

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Ca a-Sialon compacts pressurelessly-sintered to the intermediate temperature (1 450℃) were investigated with TEM for an overall composition Ca1.8Si6.6Al5.4O1.8N14.2. It was found that in most cases, the newly-formed a-Sialon grains had no epitaxial orientation relationship with the Si3N4 particles; only occasionally heteroepitaxial nucleation of a-Sialon on a-Si3N4 was detected. Further EDAX analysis revealed a much higher Ca concentration in the non-epi- taxially nucleated a-Sialon than in the heteroepitaxially nucleated a-Sialon. Thus a possible correlation between the concentration of metal cations in the a-Sialon structure and the nucleation mechanism has been proposed, i.e. a-Sialon compositions with higher Ca concentration show a stronger trend of non-epitaxial nucleation.

  11. 77 FR 50053 - Radio Broadcasting Services; Westley, CA

    Science.gov (United States)

    2012-08-20

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Westley, CA AGENCY: Federal Communications Commission... 73 Radio, Radio broadcasting. Federal Communications Commission. Peter H. Doyle, Chief,...

  12. 78 FR 32 - Radio Broadcasting Services; Westley, CA

    Science.gov (United States)

    2013-01-02

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Westley, CA AGENCY: Federal Communications Commission.... 8. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications...

  13. 77 FR 64758 - Radio Broadcasting Services; Randsburg, CA

    Science.gov (United States)

    2012-10-23

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Randsburg, CA AGENCY: Federal Communications... Radio, Radio broadcasting. Federal Communications Commission. Nazifa Sawez, Assistant Chief,...

  14. A vaccination strategy to SEIR-CA model

    Science.gov (United States)

    Almuzakki, Muhammad Zaki; Nuraini, Nuning

    2016-04-01

    A combination between Susceptible-Exposed-Infected-Removed (SEIR) model and Cellular Automaton (CA) called SEIR-CA model has been proposed to simulate spreading diseases through populations. We make an improvement to the parameter which describe the impact of neighborhood in CA system. We also propose a vaccination strategy to the model. Three examples are given to illustrate the model. The first one shows that the previously established SEIR-CA model does not work properly in a population with randomly distributed individuals. After an improvement to the neighborhood impact parameter has been made, the model works properly in a population with randomly distributed individuals and it is shown in the second example. The last example shows the spreading mechanisms with a chosen vaccination strategy. We also show that the vaccination strategy can reduce the number of infected individuals and can suppress the spread of the diseases.

  15. Caffeine-induced Ca2+ transients and exocytosis in Paramecium cells. A correlated Ca2+ imaging and quenched-flow/freeze-fracture analysis.

    Science.gov (United States)

    Klauke, N; Plattner, H

    1998-01-01

    Caffeine causes a [Ca2+]i increase in the cortex of Paramecium cells, followed by spillover with considerable attenuation, into central cell regions. From [Ca2+]resti approximately 50 to 80 nm, [Ca2+]acti rises within /=2 sec. Chelation of Ca2+o considerably attenuated [Ca2+]i increase. Therefore, caffeine may primarily mobilize cortical Ca2+ pools, superimposed by Ca2+ influx and spillover (particularly in tl cells with empty trichocyst docking sites). In nd cells, caffeine caused trichocyst contents to decondense internally (Ca2+-dependent stretching, normally occurring only after membrane fusion). With 7S cells this usually occurred only to a small extent, but with increasing frequency as [Ca2+]i signals were reduced by [Ca2+]o chelation. In this case, quenched-flow and ultrathin section or freeze-fracture analysis revealed dispersal of membrane components (without fusion) subsequent to internal contents decondensation, opposite to normal membrane fusion when a full [Ca2+]i signal was generated by caffeine stimulation (with Ca2+i and Ca2+o available). We conclude the following. (i) Caffeine can mobilize Ca2+ from cortical stores independent of the presence of Ca2+o. (ii) To yield adequate signals for normal exocytosis, Ca2+ release and Ca2+ influx both have to occur during caffeine stimulation. (iii) Insufficient [Ca2+]i increase entails caffeine-mediated access of Ca2+ to the secretory contents, thus causing their decondensation before membrane fusion can occur. (iv) Trichocyst decondensation in turn gives a signal for an unusual dissociation of docking/fusion components at the cell membrane. These observations imply different threshold [Ca2+]i-values for membrane fusion and contents discharge.

  16. BK potassium channels control transmitter release at CA3-CA3 synapses in the rat hippocampus.

    Science.gov (United States)

    Raffaelli, Giacomo; Saviane, Chiara; Mohajerani, Majid H; Pedarzani, Paola; Cherubini, Enrico

    2004-05-15

    Large conductance calcium- and voltage-activated potassium channels (BK channels) activate in response to calcium influx during action potentials and contribute to the spike repolarization and fast afterhyperpolarization. BK channels targeted to active zones in presynaptic nerve terminals have been shown to limit calcium entry and transmitter release by reducing the duration of the presynaptic spike at neurosecretory nerve terminals and at the frog neuromuscular junction. However, their functional role in central synapses is still uncertain. In the hippocampus, BK channels have been proposed to act as an 'emergency brake' that would control transmitter release only under conditions of excessive depolarization and accumulation of intracellular calcium. Here we demonstrate that in the CA3 region of hippocampal slice cultures, under basal experimental conditions, the selective BK channel blockers paxilline (10 microM) and iberiotoxin (100 nM) increase the frequency, but not the amplitude, of spontaneously occurring action potential-dependent EPSCs. These drugs did not affect miniature currents recorded in the presence of tetrodotoxin, suggesting that their action was dependent on action potential firing. Moreover, in double patch-clamp recordings from monosynaptically interconnected CA3 pyramidal neurones, blockade of BK channels enhanced the probability of transmitter release, as revealed by the increase in success rate, EPSC amplitude and the concomitant decrease in paired-pulse ratio in response to pairs of presynaptic action potentials delivered at a frequency of 0.05 Hz. BK channel blockers also enhanced the appearance of delayed responses, particularly following the second action potential in the paired-pulse protocol. These results are consistent with the hypothesis that BK channels are powerful modulators of transmitter release and synaptic efficacy in central neurones.

  17. Atrial natriuretic peptide regulates Ca channel in early developmental cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Lin Miao

    Full Text Available BACKGROUND: Cardiomyocytes derived from murine embryonic stem (ES cells possess various membrane currents and signaling cascades link to that of embryonic hearts. The role of atrial natriuretic peptide (ANP in regulation of membrane potentials and Ca(2+ currents has not been investigated in developmental cardiomyocytes. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the role of ANP in regulating L-type Ca(2+ channel current (I(CaL in different developmental stages of cardiomyocytes derived from ES cells. ANP decreased the frequency of action potentials (APs in early developmental stage (EDS cardiomyocytes, embryonic bodies (EB as well as whole embryo hearts. ANP exerted an inhibitory effect on basal I(CaL in about 70% EDS cardiomyocytes tested but only in about 30% late developmental stage (LDS cells. However, after stimulation of I(CaL by isoproterenol (ISO in LDS cells, ANP inhibited the response in about 70% cells. The depression of I(CaL induced by ANP was not affected by either Nomega, Nitro-L-Arginine methyl ester (L-NAME, a nitric oxide synthetase (NOS inhibitor, or KT5823, a cGMP-dependent protein kinase (PKG selective inhibitor, in either EDS and LDS cells; whereas depression of I(CaL by ANP was entirely abolished by erythro-9-(2-Hydroxy-3-nonyl adenine (EHNA, a selective inhibitor of type 2 phosphodiesterase(PDE2 in most cells tested. CONCLUSION/SIGNIFICANCES: Taken together, these results indicate that ANP induced depression of action potentials and I(CaL is due to activation of particulate guanylyl cyclase (GC, cGMP production and cGMP-activation of PDE2 mediated depression of adenosine 3', 5'-cyclic monophophate (cAMP-cAMP-dependent protein kinase (PKA in early cardiomyogenesis.

  18. EST Table: CA946045 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available CA946045 KI000081 11/12/09 GO hit GO:0006812(cation transport)|GO:0015299(solute:hy...e: Full=Cell volume regulation protein A 10/08/30 n.h 10/08/28 n.h 10/09/10 n.h 10/09/10 n.h 10/09/10 n.h CA946045 L9 ...

  19. Secure electronic commerce communication system based on CA

    Science.gov (United States)

    Chen, Deyun; Zhang, Junfeng; Pei, Shujun

    2001-07-01

    In this paper, we introduce the situation of electronic commercial security, then we analyze the working process and security for SSL protocol. At last, we propose a secure electronic commerce communication system based on CA. The system provide secure services such as encryption, integer, peer authentication and non-repudiation for application layer communication software of browser clients' and web server. The system can implement automatic allocation and united management of key through setting up the CA in the network.

  20. Type 2 diabetes mellitus and CA 19-9 levels

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To prospectively investigate serum CA 19-9 levels in type 2 diabetic patients in comparison with age- and gender-matched control subjects. METHODS: We recorded duration of diabetes and examined fasting glucose levels, HbA1c levels and serum CA 19-9 levels in 76 type 2 diabetic patients and 76 controls. Abdominal CT was performed in order to eliminate abdominal malignancy in the diabetic and control groups. RESULTS: The average CA 19-9 level was 46.0 ± 22.4 U/mL for diabetic patients whereas it was 9.97 ± 7.1 U/mL for the control group (P < 0.001 ). Regression analysis showed a positive correlation between diabetes and CA 19-9 independent from age, gender, glucose level and HbA1c level (t = 8.8, P < 001 ). Two of the diabetic patients were excluded from the study because of abdominal malignancy shown by CT at the initial evaluation. For all patients, abdominal CT showed no pancreatic abnormalities. CONCLUSION: CA 19-9 is a tumor-associated antigen, which is elevated in pancreatic, upper gastrointestinal tract, ovarian hepatocellular, and colorectal cancers, as well as in inflammatory conditions of the hepatobiliary system, biliary obstruction and in thyroid diseases. Diabetes has been claimed to be a risk factor for pancreatic cancer, which is increasing its incidence and has one of the lowest survival rates of all cancers. CA 19-9 is used in the diagnosis of pancreatic cancer but is also a marker of pancreatic tissue damage that might be caused by diabetes. We propose that a higher cutoff value of CA 19-9 should be used in diabetics to differentiate benign and malignant pancreatic disease, and subtle elevations of CA 19-9 in diabetics should be considered as the indication of exocrine pancreatic dysfunction.

  1. Design of CA System%CA系统的设计

    Institute of Scientific and Technical Information of China (English)

    张万斌

    2008-01-01

    目前网上身份识别主要采用通过认证中心(CA)对申请证书的用户发放电子证书的方式.本文介绍了依据现有国际标准,能够生成、管理、发放X509(V3.0)证书的认证中心(CA)系统的设计.

  2. The Ca(2+ influence on calmodulin unfolding pathway: a steered molecular dynamics simulation study.

    Directory of Open Access Journals (Sweden)

    Yong Zhang

    Full Text Available The force-induced unfolding of calmodulin (CaM was investigated at atomistic details with steered molecular dynamics. The two isolated CaM domains as well as the full-length CaM were simulated in N-C-terminal pulling scheme, and the isolated N-lobe of CaM was studied specially in two other pulling schemes to test the effect of pulling direction and compare with relevant experiments. Both Ca(2+-loaded CaM and Ca(2+-free CaM were considered in order to define the Ca(2+ influence to the CaM unfolding. The results reveal that the Ca(2+ significantly affects the stability and unfolding behaviors of both the isolated CaM domains and the full-length CaM. In Ca(2+-loaded CaM, N-terminal domain unfolds in priori to the C-terminal domain. But in Ca(2+-free CaM, the unfolding order changes, and C-terminal domain unfolds first. The force-extension curves of CaM unfolding indicate that the major unfolding barrier comes from conquering the interaction of two EF-hand motifs in both N- and C- terminal domains. Our results provide the atomistic-level insights in the force-induced CaM unfolding and explain the observation in recent AFM experiments.

  3. Role of glycolytically generated ATP for CaMKII-mediated regulation of intracellular Ca2+ signaling in bovine vascular endothelial cells.

    Science.gov (United States)

    Aromolaran, Ademuyiwa S; Zima, Aleksey V; Blatter, Lothar A

    2007-07-01

    The role of glycolytically generated ATP in Ca(2+)/calmodulin-dependent kinase II (CaMKII)-mediated regulation of intracellular Ca(2+) signaling was examined in cultured calf pulmonary artery endothelial (CPAE) cells. Exposure of cells (extracellular Ca(2+) concentration = 2 mM) to glycolytic inhibitors 2-deoxy-D-glucose (2-DG), pyruvate (pyr) + beta-hydroxybutyrate (beta-HB), or iodoacetic acid (IAA) caused an increase of intracellular Ca(2+) concentration ([Ca(2+)](i)). CaMKII inhibitors (KN-93, W-7) triggered a similar increase of [Ca(2+)](i). The rise of [Ca(2+)](i) was characterized by a transient spike followed by a small sustained plateau of elevated [Ca(2+)](i). In the absence of extracellular Ca(2+) 2-DG caused an increase in [Ca(2+)](i), suggesting that inhibition of glycolysis directly triggered release of Ca(2+) from intracellular endoplasmic reticulum (ER) Ca(2+) stores. The inositol-1,4,5-trisphosphate receptor (IP(3)R) inhibitor 2-aminoethoxydiphenyl borate abolished the KN-93- and 2-DG-induced Ca(2+) response. Ca(2+) release was initiated in peripheral cytoplasmic processes from which activation propagated as a [Ca(2+)](i) wave toward the central region of the cell. Focal application of 2-DG resulted in spatially confined elevations of [Ca(2+)](i). Propagating [Ca(2+)](i) waves were preceded by [Ca(2+)](i) oscillations and small, highly localized elevations of [Ca(2+)](i) (Ca(2+) puffs). Inhibition of glycolysis with 2-DG reduced the KN-93-induced Ca(2+) response, and vice versa during inhibition of CaMKII 2-DG-induced Ca(2+) release was attenuated. Similar results were obtained with pyr + beta-HB and W-7. Furthermore, 2-DG and IAA caused a rapid increase of intracellular Mg(2+) concentration, indicating a concomitant drop of cellular ATP levels. In conclusion, CaMKII exerts a profound inhibition of ER Ca(2+) release in CPAE cells, which is mediated by glycolytically generated ATP, possibly through ATP-dependent phosphorylation of the IP(3)R.

  4. A potential kidney-bone axis involved in the rapid minute-to-minute regulation of plasma Ca2+

    DEFF Research Database (Denmark)

    Nordholm, Anders; Mace, Maria L; Gravesen, Eva;

    2015-01-01

    of plasma-Ca(2+) (p-Ca(2+)) takes place via an exchange mechanism of Ca(2+) between plasma and bone. A labile Ca storage pool exists on bone surfaces storing excess or supplying Ca when blood Ca is lowered. Aim was to examine minute-to-minute regulation of p-Ca(2+) in the very early phase of acute uremia...

  5. Signal integration by Ca2+ regulates intestinal stem cell activity

    Science.gov (United States)

    Deng, Hansong; Gerencser, Akos A.; Jasper, Heinrich

    2015-01-01

    Summary Somatic stem cells (SCs) maintain tissue homeostasis by dynamically adjusting proliferation and differentiation in response to stress and metabolic cues. Here, we identify Ca2+ signaling as a central regulator of intestinal SC (ISC) activity in Drosophila. We find that dietary L-glutamate stimulates ISC division and gut growth. The metabotropic glutamate receptor (mGluR) is required in ISCs for this response and for an associated modulation of cytosolic Ca2+ oscillations that results in sustained high cytosolic Ca2+ concentrations. High cytosolic Ca2+ induces ISC proliferation by regulating Calcineurin and CREB - regulated transcriptional co-activator (CRTC). In response to a wide range of dietary and stress stimuli, ISCs reversibly transition between Ca2+ oscillation states that represent poised or activated modes of proliferation, respectively. We propose that the dynamic regulation of intracellular Ca2+ levels allows effective integration of diverse mitogenic signals in ISCs to tailor their proliferative activity to the needs of the tissue. PMID:26633624

  6. Ion pathways in the sarcoplasmic reticulum Ca2+-ATPase.

    Science.gov (United States)

    Bublitz, Maike; Musgaard, Maria; Poulsen, Hanne; Thøgersen, Lea; Olesen, Claus; Schiøtt, Birgit; Morth, J Preben; Møller, Jesper Vuust; Nissen, Poul

    2013-04-12

    The sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) is a transmembrane ion transporter belonging to the P(II)-type ATPase family. It performs the vital task of re-sequestering cytoplasmic Ca(2+) to the sarco/endoplasmic reticulum store, thereby also terminating Ca(2+)-induced signaling such as in muscle contraction. This minireview focuses on the transport pathways of Ca(2+) and H(+) ions across the lipid bilayer through SERCA. The ion-binding sites of SERCA are accessible from either the cytoplasm or the sarco/endoplasmic reticulum lumen, and the Ca(2+) entry and exit channels are both formed mainly by rearrangements of four N-terminal transmembrane α-helices. Recent improvements in the resolution of the crystal structures of rabbit SERCA1a have revealed a hydrated pathway in the C-terminal transmembrane region leading from the ion-binding sites to the cytosol. A comparison of different SERCA conformations reveals that this C-terminal pathway is exclusive to Ca(2+)-free E2 states, suggesting that it may play a functional role in proton release from the ion-binding sites. This is in agreement with molecular dynamics simulations and mutational studies and is in striking analogy to a similar pathway recently described for the related sodium pump. We therefore suggest a model for the ion exchange mechanism in P(II)-ATPases including not one, but two cytoplasmic pathways working in concert.

  7. Interaction of heavy metals with membrane Ca2+ channels

    Institute of Scientific and Technical Information of China (English)

    PengSQ; HajelRK

    2002-01-01

    The objective of our study was to determine if specific types of high voltage-activated Ca2+ channels,typically found in neurons were affected differentially by MeHg,Hg2+ and Pb2+.Expression cDNA clones of α1C,α1B or α1E subunits coding for neuronal L-,N- and R- subtypes respectively,were combined with α2b δ and β3 Ca2+ channel subunits of human neuronal origin to transfect HEK293 cells.Current was measured using whole cell voltage clamp recording techniques.It the present studies,we conclude: (1)neurotoxic heavy metals such as MeHg,Hg2+ and Pb impair the function of voltage-gated Ca2+ channels at low μmolar to sub-μmolar concentrations-concentrations in the range of which are pathologically and environmentally relevant; (2)a particular metal,i.e.Pb2+,may inhibit function of phenotypically distince Ca2+ channels with variable potency; (3)different metals have differing “orders of potency” at inhibiting defined populations of Ca2+ channels; (4)for “susceptible populations” of patients with either underlying diseases or genetic alter ations of Ca2+ channel function,these metals may have heightened effectiveness.As such,for these populations,environmental toxic metals could produce a more dominant neurotoxicity.

  8. Meigs' syndrome with elevated CA 125: case report

    Directory of Open Access Journals (Sweden)

    Sabas Carlos Vieira

    Full Text Available CONTEXT: Meigs' syndrome consists of a benign ovarian tumor accompanied by ascites and hydrothorax. Elevated serum CA 125 levels in postmenopausal women with solid adnexal masses, ascites and pleural effusion are highly suggestive for malignant ovarian tumor. However, patients with Meigs' syndrome can also have elevated serum CA 125 levels. The authors report a case of Meigs' syndrome with elevated CA 125 level. OBJECTIVE: This is a case report of Meigs' syndrome with elevated CA 125 level. CASE REPORT: A 65-year-old Brazilian woman had presented progressive dyspnea, weight loss and decline in general condition over the 7 months preceding admission to our service. In another hospital, the patient had been submitted to thoracic drainage due to pleural effusion. With recurrence of the pleural effusion and increase in abdominal volume due to ascites and a pelvic mass, the patient sought our service. Transvaginal ultrasound showed an extensive adnexal solid mass of 16.4 x 10.8 cm located in the pelvis without exact limits, and the serum CA 125 level was elevated. With a preoperative diagnosis of ovarian carcinoma, the patient was submitted to exploratory laparotomy, which revealed a left ovarian tumor. The frozen section diagnosis was thecoma. Total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed. The histology of the specimen confirmed the diagnosis of thecoma. The patient was asymptomatic with a normal serum CA 125 level 20 months after the operation.

  9. Ca2+ influx through L-type Ca2+ channels and Ca2+-induced Ca2+ release regulate cAMP accumulation and Epac1-dependent ERK 1/2 activation in INS-1 cells.

    Science.gov (United States)

    Pratt, Evan P S; Salyer, Amy E; Guerra, Marcy L; Hockerman, Gregory H

    2016-01-05

    We previously reported that INS-1 cells expressing the intracellular II-III loop of the L-type Ca(2+) channel Cav1.2 (Cav1.2/II-III cells) are deficient in Ca(2+)-induced Ca(2+) release (CICR). Here we show that glucose-stimulated ERK 1/2 phosphorylation (GSEP) is slowed and reduced in Cav1.2/II-III cells compared to INS-1 cells. This parallels a decrease in glucose-stimulated cAMP accumulation (GS-cAMP) in Cav1.2/II-III cells. Influx of Ca(2+) via L-type Ca(2+) channels and CICR play roles in both GSEP and GS-cAMP in INS-1 cells since both are inhibited by nicardipine or ryanodine. Further, the Epac1-selective inhibitor CE3F4 abolishes glucose-stimulated ERK activation in INS-1 cells, as measured using the FRET-based sensor EKAR. The non-selective Epac antagonist ESI-09 but not the Epac2-selective antagonist ESI-05 nor the PKA antagonist Rp-cAMPs inhibits GSEP in both INS-1 and Cav1.2/II-III cells. We conclude that L-type Ca(2+) channel-dependent cAMP accumulation, that's amplified by CICR, activates Epac1 and drives GSEP in INS-1 cells.

  10. Ca isotopic geochemistry of an Antarctic aquatic system

    Science.gov (United States)

    Lyons, W. Berry; Bullen, Thomas D.; Welch, Kathleen A.

    2017-01-01

    The McMurdo Dry Valleys, Antarctica, are a polar desert ecosystem. The hydrologic system of the dry valleys is linked to climate with ephemeral streams that flow from glacial melt during the austral summer. Past climate variations have strongly influenced the closed-basin, chemically stratified lakes on the valley floor. Results of previous work point to important roles for both in-stream processes (e.g., mineral weathering, precipitation and dissolution of salts) and in-lake processes (e.g., mixing with paleo-seawater and calcite precipitation) in determining the geochemistry of these lakes. These processes have a significant influence on calcium (Ca) biogeochemistry in this aquatic ecosystem, and thus variations in Ca stable isotope compositions of the waters can aid in validating the importance of these processes. We have analyzed the Ca stable isotope compositions of streams and lakes in the McMurdo Dry Valleys. The results validate the important roles of weathering of aluminosilicate minerals and/or CaCO3 in the hyporheic zone of the streams, and mixing of lake surface water with paleo-seawater and precipitation of Ca-salts during cryo-concentration events to form the deep lake waters. The lakes in the McMurdo Dry Valleys evolved following different geochemical pathways, evidenced by their unique, nonsystematic Ca isotope signatures.

  11. Transcriptional regulation of voltage-gated Ca(2+) channels.

    Science.gov (United States)

    González-Ramírez, Ricardo; Felix, Ricardo

    2017-03-31

    The transcriptional regulation of voltage-gated Ca(2+) (CaV ) channels is an emerging research area that promises to improve our understanding of how many relevant physiological events are shaped in the central nervous system, the skeletal muscle, and other tissues. Interestingly, a picture of how transcription of CaV channel subunit genes is controlled is evolving with the identification of the promoter regions required for tissue-specific expression, and the identification of transcription factors that control their expression. These promoters share several characteristics that include multiple transcriptional start sites, lack of a TATA box, and the presence of elements conferring tissue-selective expression. Likewise, changes in CaV channel expression occur throughout development, following ischemia, seizures, or chronic drug administration. This review focuses on insights achieved regarding the control of CaV channel gene expression. To further understand the complexities of expression and to increase the possibilities of detecting CaV channel alterations causing human disease, a deeper knowledge on the structure of the 5' upstream regions of the genes encoding these remarkable proteins will be necessary. This article is protected by copyright. All rights reserved.

  12. Imaging of mitochondrial Ca2+ dynamics in astrocytes using cell-specific mitochondria-targeted GCaMP5G/6s: mitochondrial Ca2+ uptake and cytosolic Ca2+ availability via the endoplasmic reticulum store.

    Science.gov (United States)

    Li, Hailong; Wang, Xiaowan; Zhang, Nannan; Gottipati, Manoj K; Parpura, Vladimir; Ding, Shinghua

    2014-12-01

    Mitochondrial Ca(2+) plays a critical physiological role in cellular energy metabolism and signaling, and its overload contributes to various pathological conditions including neuronal apoptotic death in neurological diseases. Live cell mitochondrial Ca(2+) imaging is an important approach to understand mitochondrial Ca(2+) dynamics. Recently developed GCaMP genetically-encoded Ca(2+) indicators provide unique opportunity for high sensitivity/resolution and cell type-specific mitochondrial Ca(2+) imaging. In the current study, we implemented cell-specific mitochondrial targeting of GCaMP5G/6s (mito-GCaMP5G/6s) and used two-photon microscopy to image astrocytic and neuronal mitochondrial Ca(2+) dynamics in culture, revealing Ca(2+) uptake mechanism by these organelles in response to cell stimulation. Using these mitochondrial Ca(2+) indicators, our results show that mitochondrial Ca(2+) uptake in individual mitochondria in cultured astrocytes and neurons can be seen after stimulations by ATP and glutamate, respectively. We further studied the dependence of mitochondrial Ca(2+) dynamics on cytosolic Ca(2+) changes following ATP stimulation in cultured astrocytes by simultaneously imaging mitochondrial and cytosolic Ca(2+) increase using mito-GCaMP5G and a synthetic organic Ca(2+) indicator, x-Rhod-1, respectively. Combined with molecular intervention in Ca(2+) signaling pathway, our results demonstrated that the mitochondrial Ca(2+) uptake is tightly coupled with inositol 1,4,5-trisphosphate receptor-mediated Ca(2+) release from the endoplasmic reticulum and the activation of G protein-coupled receptors. The current study provides a novel approach to image mitochondrial Ca(2+) dynamics as well as Ca(2+) interplay between the endoplasmic reticulum and mitochondria, which is relevant for neuronal and astrocytic functions in health and disease.

  13. Meiosis, egg activation, and nuclear envelope breakdown are differentially reliant on Ca2+, whereas germinal vesicle breakdown is Ca2+ independent in the mouse oocyte

    Science.gov (United States)

    Tombes, R. M.; Simerly, C.; Borisy, G. G.; Schatten, G.

    1992-01-01

    During early development, intracellular Ca2+ mobilization is not only essential for fertilization, but has also been implicated during other meiotic and mitotic events, such as germinal vesicle breakdown (GVBD) and nuclear envelope breakdown (NEBD). In this study, the roles of intracellular and extracellular Ca2+ were examined during meiotic maturation and reinitiation at parthenogenetic activation and during first mitosis in a single species using the same methodologies. Cumulus-free metaphase II mouse oocytes immediately resumed anaphase upon the induction of a large, transient Ca2+ elevation. This resumption of meiosis and associated events, such as cortical granule discharge, were not sensitive to extracellular Ca2+ removal, but were blocked by intracellular Ca2+ chelators. In contrast, meiosis I was dependent on external Ca2+; in its absence, the formation and function of the first meiotic spindle was delayed, the first polar body did not form and an interphase-like state was induced. GVBD was not dependent on external Ca2+ and showed no associated Ca2+ changes. NEBD at first mitosis in fertilized eggs, on the other hand, was frequently, but not always associated with a brief Ca2+ transient and was dependent on Ca2+ mobilization. We conclude that GVBD is Ca2+ independent, but that the dependence of NEBD on Ca2+ suggests regulation by more than one pathway. As cells develop from Ca(2+)-independent germinal vesicle oocytes to internal Ca(2+)-dependent pronuclear eggs, internal Ca2+ pools increase by approximately fourfold.

  14. The CA3 "backprojection" to the dentate gyrus.

    Science.gov (United States)

    Scharfman, Helen E

    2007-01-01

    The hippocampus is typically described in the context of the trisynaptic circuit, a pathway that relays information from the perforant path to the dentate gyrus, dentate to area CA3, and CA3 to area CA1. Associated with this concept is the assumption that most hippocampal information processing occurs along the trisynaptic circuit. However, the entorhinal cortex may not be the only major extrinsic input to consider, and the trisynaptic circuit may not be the only way information is processed in hippocampus. Area CA3 receives input from a variety of sources, and may be as much of an "entry point" to hippocampus as the dentate gyrus. The axon of CA3 pyramidal cells targets diverse cell types, and has commissural projections, which together make it able to send information to much more of the hippocampus than granule cells. Therefore, CA3 pyramidal cells seem better designed to spread information through hippocampus than the granule cells. From this perspective, CA3 may be a point of entry that receives information which needs to be "broadcasted," whereas the dentate gyrus may be a point of entry that receives information with more selective needs for hippocampal processing. One aspect of the argument that CA3 pyramidal cells have a widespread projection is based on a part of its axonal arbor that has received relatively little attention, the collaterals that project in the opposite direction to the trisynaptic circuit, "back" to the dentate gyrus. The evidence for this "backprojection" to the dentate gyrus is strong, particularly in area CA3c, the region closest to the dentate gyrus, and in temporal hippocampus. The influence on granule cells is indirect, through hilar mossy cells and GABAergic neurons of the dentate gyrus, and appears to include direct projections in the case of CA3c pyramidal cells of ventral hippocampus. Physiological studies suggest that normally area CA3 does not have a robust excitatory influence on granule cells, but serves instead to inhibit

  15. Expression of PIK3CA, PTEN mRNA and PIK3CA mutations in primary breast cancer

    DEFF Research Database (Denmark)

    Palimaru, Irina; Brügmann, Anja; Wium-Andersen, Marie Kim;

    2013-01-01

    tissue samples of breast carcinoma and normal breast tissue were obtained from 175 breast cancer patients at the time of primary surgery, of these 105 patients were lymph node positive. Expression of PIK3CA and PTEN mRNA was quantified with Quantitative Real Time PCR. Somatic mutations in exon 9 and exon......PURPOSE: High activity of the intracellular phosphatidylinositol-3 kinase (PI3K) pathway is common in breast cancer. Here, we explore differences in expression of important PI3K pathway regulators: the activator, phosphatidylinositol-3-kinase catalytic subunit alpha (PIK3CA), and the tumour...... suppressor, phosphatase and tensin homolog (PTEN), in breast carcinoma tissue and normal breast tissue. Furthermore, we examine whether expression of PIK3CA and PTEN mRNA and occurrence of PIK3CA mutations are associated with lymph node metastases in patients with primary breast cancer. METHODS: Paired...

  16. Arabidopsis cysteine proteinase inhibitor AtCYSb interacts with a Ca(2+)-dependent nuclease, AtCaN2.

    Science.gov (United States)

    Guo, Kunyuan; Bu, Yuanyuan; Takano, Tetsuo; Liu, Shenkui; Zhang, Xinxin

    2013-11-01

    Plant cysteine proteinase inhibitors (cystatins) play important roles in plant defense mechanisms. Some proteins that interact with cystatins may defend against abiotic stresses. Here, we showed that AtCaN2, a Ca(2+)-dependent nuclease in Arabidopsis, is transcribed in senescent leaves and stems and interacts with an Arabidopsis cystatin (AtCYSb) in a yeast two-hybrid screen. The interaction between AtCYSb and AtCaN2 was confirmed by in vitro pull-down assay and bimolecular fluorescence complementation. Agarose gel electrophoresis showed that the nuclease activity of AtCaN2 against λDNA was inhibited by AtCYSb, which suggests that AtCYSb regulates nucleic acid degradation in cells.

  17. Migration behaviour of twaite shad Alosa fallax assessed by otolith Sr:Ca and Ba:Ca profiles.

    Science.gov (United States)

    Magath, V; Marohn, L; Fietzke, J; Frische, M; Thiel, R; Dierking, J

    2013-06-01

    Individual migration behaviour during the juvenile and adult life phase of the anadromous twaite shad Alosa fallax in the Elbe estuary was examined using otolith Sr:Ca and Ba:Ca profiles. Between hatching and the end of the first year of life, juveniles showed two migration patterns. Pattern one exhibited a single downstream migration from fresh water to the sea with no return into fresh water. In contrast, pattern two showed a first migration into the sea, then a return into fresh water and, finally, a second downstream migration into marine water. This first report of migration plasticity for A. fallax points to different exposure times to estuarine threats depending on the migration strategy. In adults, high Sr:Ca and low Ba:Ca in the majority of individuals confirmed prior reports of a primarily marine habitat use. Patterns reflecting spawning migrations were rarely observed on otoliths, possibly due to the short duration of visits to fresh water.

  18. Thermodynamic Study on BaO-CaO-CaF2 Slags for Dephosphorization of Molten Steel

    Institute of Scientific and Technical Information of China (English)

    TIAN Zhi-hong; CAI Kai-ke; WANG Xin-hua; ZHU Li-xin; WANG Tao; SHI Hong-zhi; YIN Xiao-dong

    2005-01-01

    The molten steel was dephosphorized by high basic BaO-based slags (BaO-CaO-CaF2) to achieve ultra low phosphorus level. The dephosphorization ability of the BaO-CaO-CaF2 slags was tested. The phosphate capacity of this slag system at 1 620 C varied from 1018.03 to 1019.11 with an activity coefficient of P2O5 ranging from 10-19.47 to 10-18.09. The effect of BaO content, initial phosphorus content and oxygen potential of molten steel on dephosphorization was discussed. The phosphorus pick-up by the BaO-based slags was studied.

  19. Strain induced phenomena in Ca(OH)/sub 2/ made by reaction of CaO with water vapor

    Energy Technology Data Exchange (ETDEWEB)

    Beruto, D.; Searcy, A.W.; Barco, L.; Belleri, G.

    1980-01-01

    Three physically distinguishable, poorly crystalline forms of Ca(OH)/sub 2/ which are made by reactions of water vapor at 25/sup 0/C with CaO powders evolve heat and develop sharper x-ray diffraction patterns when heated to 300/sup 0/C. Measurements of x-ray diffraction peak line breadths, surface areas, porosities, and pore size distributions were made before and after heat treatment. The exothermic process of the one of these forms of Ca(OH)/sub 2/ which is nonporous is recrystallization of the highly strained solid to essentially unstrained crystals. The exothermic process in two porous forms of Ca(OH)/sub 2/, not only reduces their internal strains, but also reduces their surface areas and porosities.

  20. Ryanodine Receptor Phosphorylation by CaMKII Promotes Spontaneous Ca2+ Release Events in a Rodent Model of Early Stage Diabetes: the Arrhythmogenic Substrate

    Science.gov (United States)

    Sommese, Leandro; Valverde, Carlos A; Blanco, Paula; Castro, María Cecilia; Rueda, Omar Velez; Kaetzel, Marcia; Dedman, John; Anderson, Mark E.; Mattiazzi, Alicia; Palomeque, Julieta

    2016-01-01

    Background Heart failure and arrhythmias occur more frequently in patients with type 2 diabetes (T2DM) than in the general population. T2DM is preceded by a prediabetic condition marked by elevated reactive oxygen species (ROS) and subclinical cardiovascular defects. Although multifunctional Ca2+ calmodulin-dependent protein kinase II (CaMKII) is ROS-activated and CaMKII hyperactivity promotes cardiac diseases, a link between prediabetes and CaMKII in the heart is unprecedented. Objectives to prove the hypothesis that increased ROS and CaMKII activity contribute to heart failure and arrhythmogenic mechanisms in early stage diabetes. Methods-Results Echocardiography, electrocardiography, biochemical and intracellular Ca2+ (Ca2+i) determinations were performed in fructose-rich diet -induced impaired glucose tolerance, a prediabetes model, in rodents. Fructose-rich diet rats showed decreased contractility and hypertrophy associated with increased CaMKII activity, ROS production, oxidized CaMKII and enhanced CaMKII-dependent ryanodine receptor (RyR2) phosphorylation compared to rats fed with control diet. Isolated cardiomyocytes from fructose-rich diet showed increased spontaneous Ca2+i release events associated with spontaneous contractions, which were prevented by KN-93, a CaMKII inhibitor, or addition of Tempol, a ROS scavenger, to the diet. Moreover, fructose-rich diet myocytes showed increased diastolic Ca2+ during the burst of spontaneous Ca2+i release events. Micetreated with Tempol or with sarcoplasmic reticulum-targeted CaMKII-inhibition by transgenic expression of the CaMKII inhibitory peptide AIP, were protected from fructose-rich diet-induced spontaneous Ca2+i release events, spontaneous contractions and arrhythmogenes is in vivo, despite ROS increases. Conclusions RyR2 phosphorylation by ROS-activated CaMKII, contributes to impaired glucose tolerance-induced arrhythmogenic mechanisms, suggesting that CaMKII inhibition could prevent prediabetic

  1. Parvalbumin is a mobile presynaptic Ca2+ buffer in the calyx of Held that accelerates the decay of Ca2+ and short-term facilitation.

    Science.gov (United States)

    Müller, Martin; Felmy, Felix; Schwaller, Beat; Schneggenburger, Ralf

    2007-02-28

    Presynaptic Ca2+ signaling plays a crucial role in short-term plasticity of synaptic transmission. Here, we studied the role of mobile endogenous presynaptic Ca2+ buffer(s) in modulating paired-pulse facilitation at a large excitatory nerve terminal in the auditory brainstem, the calyx of Held. To do so, we assessed the effect of presynaptic whole-cell recording, which should lead to the diffusional loss of endogenous mobile Ca2+ buffers, on paired-pulse facilitation and on intracellular Ca2+ concentration ([Ca2+]i) transients evoked by action potentials. In unperturbed calyces briefly preloaded with the Ca2+ indicator fura-6F, the [Ca2+]i transient decayed surprisingly fast (tau(fast), approximately 30 ms). Presynaptic whole-cell recordings made without additional Ca2+ buffers slowed the decay kinetics of [Ca2+]i and paired-pulse facilitation (twofold to threefold), but the amplitude of the [Ca2+]i transient was changed only marginally. The fast [Ca2+]i decay was restored by adding the slow Ca2+ buffer EGTA (50-100 microM) or parvalbumin (100 microM), a Ca2+-binding protein with slow Ca2+-binding kinetics, to the presynaptic pipette solution. In contrast, the fast Ca2+ buffer fura-2 strongly reduced the amplitude of the [Ca2+]i transient and slowed its decay, suggesting that the mobile endogenous buffer in calyces of Held has slow, rather than fast, binding kinetics. In parvalbumin knock-out mice, the decay of [Ca2+]i and facilitation was slowed approximately twofold compared with wild-type mice, similar to what is observed during whole-cell recordings in rat calyces of Held. Thus, in young calyces of Held, a mobile Ca2+ buffer with slow binding kinetics, primarily represented by parvalbumin, accelerates the decay of spatially averaged [Ca2+]i and paired-pulse facilitation.

  2. CGP37157, an inhibitor of the mitochondrial Na+/Ca2+ exchanger, protects neurons from excitotoxicity by blocking voltage-gated Ca2+ channels.

    Science.gov (United States)

    Ruiz, A; Alberdi, E; Matute, C

    2014-04-10

    Inhibition of the mitochondrial Na(+)/Ca(2+) exchanger (NCLX) by CGP37157 is protective in models of neuronal injury that involve disruption of intracellular Ca(2+) homeostasis. However, the Ca(2+) signaling pathways and stores underlying neuroprotection by that inhibitor are not well defined. In the present study, we analyzed how intracellular Ca(2+) levels are modulated by CGP37157 (10 μM) during NMDA insults in primary cultures of rat cortical neurons. We initially assessed the presence of NCLX in mitochondria of cultured neurons by immunolabeling, and subsequently, we analyzed the effects of CGP37157 on neuronal Ca(2+) homeostasis using cameleon-based mitochondrial Ca(2+) and cytosolic Ca(2+) ([Ca(2+)]i) live imaging. We observed that NCLX-driven mitochondrial Ca(2+) exchange occurs in cortical neurons under basal conditions as CGP37157 induced a decrease in [Ca(2)]i concomitant with a Ca(2+) accumulation inside the mitochondria. In turn, CGP37157 also inhibited mitochondrial Ca(2+) efflux after the stimulation of acetylcholine receptors. In contrast, CGP37157 strongly prevented depolarization-induced [Ca(2+)]i increase by blocking voltage-gated Ca(2+) channels (VGCCs), whereas it did not induce depletion of ER Ca(2+) stores. Moreover, mitochondrial Ca(2+) overload was reduced as a consequence of diminished Ca(2+) entry through VGCCs. The decrease in cytosolic and mitochondrial Ca(2+) overload by CGP37157 resulted in a reduction of excitotoxic mitochondrial damage, characterized here by a reduction in mitochondrial membrane depolarization, oxidative stress and calpain activation. In summary, our results provide evidence that during excitotoxicity CGP37157 modulates cytosolic and mitochondrial Ca(2+) dynamics that leads to attenuation of NMDA-induced mitochondrial dysfunction and neuronal cell death by blocking VGCCs.

  3. Ca2+ and endoplasmic reticulum Ca2+-ATPase regulate the formation of silk fibers with favorable mechanical properties.

    Science.gov (United States)

    Wang, Xin; Li, Yi; Xie, Kang; Yi, Qiying; Chen, Quanmei; Wang, Xiaohuan; Shen, Hong; Xia, Qingyou; Zhao, Ping

    2015-02-01

    Calcium ions (Ca(2+)) are crucial for the conformational transition of silk fibroin in vitro, and silk fibroin conformations correlate with the mechanical properties of silk fibers. To investigate the relationship between Ca(2+) and mechanical properties of silk fibers, CaCl2 was injected into silkworms (Bombyx mori). Fourier-transform infrared spectroscopy (FTIR) analysis and mechanical testing revealed that injection of CaCl2 solution (7.5mg/g body weight) significantly increased the levels of α-helix and random coil structures of silk proteins. In addition, extension of silk fibers increased after CaCl2 injection. In mammals, sarcoplasmic reticulum Ca(2+)-ATPase in muscle and endoplasmic reticulum Ca(2+)-ATPase in other tissues (together denoted by SERCA) are responsible for calcium balance. Therefore, we analyzed the expression pattern of silkworm SERCA (BmSERCA) in silk glands and found that BmSERCA was abundant in the anterior silk gland (ASG). After injection of thapsigargin (TG) to block SERCA activity, silkworms showed a silk-spinning deficiency and their cocoons had higher calcium content compared to that of controls. Moreover, FTIR analysis revealed that the levels of α-helix and β-sheet structures increased in silk fibers from TG-injected silkworms compared to controls. The results provide evidence that BmSERCA has a key function in calcium transportation in ASG that is related to maintaining a suitable ionic environment. This ionic environment with a proper Ca(2+) concentration is crucial for the formation of silk fibers with favorable mechanical performances.

  4. Far-infrared and dc-Magnetotransport of CaMnO3 CaRuO3 Superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, P. [Max-Planck-Institut fur Feskorperforschung, Stuttgart, Germany; Boris, A. V. [Max-Planck-Institut fur Feskorperforschung, Stuttgart, Germany; Freeland, J. W. [Argonne National Laboratory (ANL); Kavich, J. J. [University of Illinois, Chicago; Chakhalian, J. [University of Arkansas; Lee, Ho Nyung [ORNL; Keimer, Bernhard [Max-Planck-Institut fur Feskorperforschung, Stuttgart, Germany

    2012-01-01

    We report temperature- and magnetic-field-dependent measurements of the dc resistivity and the far-infrared reflectivity (FIR) (photon energies {h_bar}{omega} = 50-700 cm{sup -1}) of superlattices comprising ten consecutive unit cells of the antiferromagnetic insulator CaMnO{sub 3}, and four to ten unit cells of the correlated paramagnetic metal CaRuO{sub 3}. Below the Neel temperature of CaMnO{sub 3}, the dc resistivity exhibits a logarithmic divergence upon cooling, which is associated with a large negative, isotropic magnetoresistance. The {omega} {yields} 0 extrapolation of the resistivity extracted from the FIR reflectivity, on the other hand, shows a much weaker temperature and field dependence. We attribute this behavior to scattering of itinerant charge carriers in CaRuO{sub 3} from sparse, spatially isolated magnetic defects at the CaMnO{sub 3}-CaRuO{sub 3} interfaces. This field-tunable 'transport bottleneck' effect may prove useful for functional metal-oxide devices.

  5. Synchronization of stochastic Ca²(+) release units creates a rhythmic Ca²(+) clock in cardiac pacemaker cells.

    Science.gov (United States)

    Maltsev, Anna V; Maltsev, Victor A; Mikheev, Maxim; Maltseva, Larissa A; Sirenko, Syevda G; Lakatta, Edward G; Stern, Michael D

    2011-01-19

    In sinoatrial node cells of the heart, beating rate is controlled, in part, by local Ca²(+) releases (LCRs) from the sarcoplasmic reticulum, which couple to the action potential via electrogenic Na(+)/Ca²(+) exchange. We observed persisting, roughly periodic LCRs in depolarized rabbit sinoatrial node cells (SANCs). The features of these LCRs were reproduced by a numerical model consisting of a two-dimensional array of stochastic, diffusively coupled Ca²(+) release units (CRUs) with fixed refractory period. Because previous experimental studies showed that β-adrenergic receptor stimulation increases the rate of Ca²(+) release through each CRU (dubbed I(spark)), we explored the link between LCRs and I(spark) in our model. Increasing the CRU release current I(spark) facilitated Ca²(+)-induced-Ca²(+) release and local recruitment of neighboring CRUs to fire more synchronously. This resulted in a progression in simulated LCR size (from sparks to wavelets to global waves), LCR rhythmicity, and decrease of LCR period that parallels the changes observed experimentally with β-adrenergic receptor stimulation. The transition in LCR characteristics was steeply nonlinear over a narrow range of I(spark), resembling a phase transition. We conclude that the (partial) periodicity and rate regulation of the "Calcium clock" in SANCs are emergent properties of the diffusive coupling of an ensemble of interacting stochastic CRUs. The variation in LCR period and size with I(spark) is sufficient to account for β-adrenergic regulation of SANC beating rate.

  6. Effect of Chlorine on the Viscosities and Structures of CaO-SiO2-CaCl2 Slags

    Science.gov (United States)

    Wang, Cui; Zhang, Jianliang; Liu, Zhengjian; Jiao, Kexin; Wang, Guangwei; Yang, Junqiang; Chou, Kuochih

    2016-10-01

    The viscosities of CaO-SiO2-CaCl2 (CaO/SiO2 = 1.12) slags were measured to elucidate the effect of chlorine with CaCl2 content from 0 to 15 mass pct on the slags at high temperatures, and the Raman spectra of the glassy slags were detected to account for the role of chlorine in modifying the structures of the slags. The viscosity was found to increase with decreasing temperature and to decrease with increasing chlorine content at a given temperature. The critical temperature (T CR) decreased from about 1675 K to 1621 K (1402 °C to 1348 °C) with increasing CaCl2 content from 5 to 15 mass pct, and the activation energy decreased from 226 to 152 kJ/mol with CaCl2 content increasing from 0 to 15 mass pct. Meanwhile, the Raman spectra gradually shifted to lower wavenumber, the fractions of Q 0 and Q 2 units increased and the Q 1 and Q 3 units decreased continuously, and the Q 3/Q 2 ratio generally decreased with increasing the chlorine content in the investigated slags; all of these results above demonstrated the role of network modifier of the chlorine in decreasing the degree of polymerization in the silicon-oxygen tetrahedra.

  7. Closed head injury causes hyperexcitability in rat hippocampal CA1 but not in CA3 pyramidal cells.

    Science.gov (United States)

    Griesemer, Désirée; Mautes, Angelika M

    2007-12-01

    Traumatic brain injury frequently elicits epileptic seizures hours or days after the impact. The mechanisms on cellular level are poorly understood. Because posttraumatic epilepsy appears in many cases as a temporal-lobe epilepsy which originated the hippocampus, we studied trauma-induced hyperexcitability on the cellular level in this brain area. We used the model of closed head injury to analyse the electrophysiological changes in CA1 and CA3 pyramidal cells and in interneurones of the CA1 field, which is extremely sensitive to ischemia. We found that morphologically closed head injury (CHI) led to a gradual progressive, cell type specific time course in neuronal degeneration. To analyse electrophysiological impairment we measured resting membrane potential, recorded spontaneous action potentials and induced action potentials by current pulses at different times after CHI. We found a dramatic increase in the frequency of spontaneous action potentials of CA1 but not of CA3 pyramidal cells after CHI. This hyperexcitability was maximal at 2 h (4.5-fold higher than sham), was also observed at 24 h after CHI and disappeared after 3 days. We found that CA1 interneurones responded by a much weaker increase of AP frequency after CHI. We conclude that the strong hyperexcitability after CHI is cell-type specific and transient. The understanding of the complex neuronal interactions probably offers a promising possibility for pharmacological intervention to prevent posttraumatic epilepsy.

  8. Ca(2+)-free, high-Ca2+ coronary perfusion suppresses contractility and excitation-contraction coupling energy.

    Science.gov (United States)

    Araki, J; Takaki, M; Namba, T; Mori, M; Suga, H

    1995-03-01

    We studied the mechanoenergetic effects of a short-term Ca(2+)-free, high-Ca2+ Tyrode solution coronary perfusion in eight excised, cross-circulated canine hearts. The perfusion protocol consisted of coronary perfusion with Ca(2+)-free Tyrode solution for 10 min followed by high-Ca2+ (16 mM) Tyrode solution for 5 min. This new protocol successfully induced acute contractile failure in seven hearts, without myocardial ultrastructural changes. We studied the end-systolic pressure-volume relation (slope = Emax, a contractility index) and the relation between oxygen consumption per beat (VO2) and systolic pressure-volume area (PVA) in these failing hearts. These hearts had no increase in end-diastolic pressure at a given volume, a 40% decrease in Emax and a proportional decrease in the PVA-independent VO2 for 1-4 h, but no decrease in the oxygen cost of PVA, defined as the slope of the VO2-PVA relation. The oxygen cost of Emax for Ca2+ handling, defined as the slope of the relation between PVA-independent VO2 and Emax, was unchanged in the failing hearts. We conclude that the present protocol induced left ventricular contractile failure, primarily involving the suppression of Ca2+ handling energy for excitation-contraction coupling.

  9. Upconversion luminescence of lanthanide-doped mixed CaMoO4-CaWO4 micro-/nano-materials.

    Science.gov (United States)

    Liu, Jing; Kaczmarek, Anna M; Billet, Jonas; Van Driessche, Isabel; Van Deun, Rik

    2016-08-14

    Uniform mixed CaMoO4-CaWO4 micro-/nano-materials have been successfully synthesised by a facile hydrothermal method. The morphology of these upconversion materials could be changed to different shapes and the size could also be decreased from the micro- to nano-scale by varying the type of surfactant used. It was observed that before heat treatment, the materials show relatively weak green light emission under excitation at 975 nm, whereas after heat treatment, the intensity of the upconversion luminescence increases dramatically while the intensity of the red component decreases relatively. By adjusting the molybdate/tungstate ratio, it was found that the samples with a higher molybdate content have stronger luminescence properties. XRD measurements have been done to investigate the structure of the mixed CaMoO4-CaWO4 upconversion materials. The effect of heat treatment at different temperatures on the emission spectra and XRD patterns has also been studied. TG-DTA was used to further confirm the most suitable temperature for heat treatment. The luminescence lifetimes and CIE coordinates for these samples were also determined. Additionally it was found that Gd(3+) co-doping could further increase the upconversion luminescence from these mixed CaMoO4-CaWO4 materials. Finally, monitoring the upconversion luminescence intensity as a function of laser pump power confirmed the upconversion process to be a two-photon absorption mechanism.

  10. Mitochondrial Ca(2+) uniporter (MCU)-dependent and MCU-independent Ca(2+) channels coexist in the inner mitochondrial membrane.

    Science.gov (United States)

    Bondarenko, Alexander I; Jean-Quartier, Claire; Parichatikanond, Warisara; Alam, Muhammad Rizwan; Waldeck-Weiermair, Markus; Malli, Roland; Graier, Wolfgang F

    2014-07-01

    A protein referred to as CCDC109A and then renamed to mitochondrial calcium uniporter (MCU) has recently been shown to accomplish mitochondrial Ca(2+) uptake in different cell types. In this study, we investigated whole-mitoplast inward cation currents and single Ca(2+) channel activities in mitoplasts prepared from stable MCU knockdown HeLa cells using the patch-clamp technique. In whole-mitoplast configuration, diminution of MCU considerably reduced inward Ca(2+) and Na(+) currents. This was accompanied by a decrease in occurrence of single channel activity of the intermediate conductance mitochondrial Ca(2+) current (i-MCC). However, ablation of MCU yielded a compensatory 2.3-fold elevation in the occurrence of the extra large conductance mitochondrial Ca(2+) current (xl-MCC), while the occurrence of bursting currents (b-MCC) remained unaltered. These data reveal i-MCC as MCU-dependent current while xl-MCC and b-MCC seem to be rather MCU-independent, thus, pointing to the engagement of at least two molecularly distinct mitochondrial Ca(2+) channels.

  11. Magicity of the $^{52}$Ca and $^{54}$Ca isotopes and tensor contribution within a mean--field approach

    CERN Document Server

    Grasso, Marcella

    2014-01-01

    We investigate the magicity of the isotopes $^{52}$Ca and $^{54}$Ca, that was recently confirmed by two experimental measurements, and relate it to like--particle and neutron--proton tensor effects within a mean--field description. By analyzing Ca isotopes, we show that the like--particle tensor contribution induces shell effects that render these nuclei more magic than they would be predicted by neglecting it. In particular, such induced shell effects are stronger in the nucleus $^{52}$Ca and the single--particle gaps are increased in both isotopes due to the tensor force. By studying $N=32$ and $N=34$ isotones, neutron--proton tensor effects may be isolated and their role analyzed. It is shown that neutron--proton tensor effects lead to increasing $N=32$ and $N=34$ gaps, when going along isotonic chains, from $^{58}$Fe to $^{52}$Ca, and from $^{60}$Fe to $^{54}$Ca, respectively. The mean--field calculations are perfomed by employing one Skyrme parameter set, that was introduced in a previous work by fitting...

  12. Li/Ca, B/Ca, and Mg/Ca content in sea urchin spines cultured at different temperatures and pCO2

    Science.gov (United States)

    Nguyen, T.; Eagle, R.; Courtney, T.; Ries, J. B.; Brillo, V.; Rollion-Bard, C.; Gabitov, R. I.; Tripati, A. K.

    2012-12-01

    Element/calcium ratios within biogenic calcium carbonate minerals have been used as tools to reconstruct seawater temperature and pH. Most recent studies have focused on examining systematics governing elemental incorporation in coral, foraminifera, and otoliths [1-3, etc.]. In this study we focus on examining Li/Ca, B/Ca, and Mg/Ca ratios in sea urchins cultured at different temperatures and pCO2. We conducted in situ secondary ion mass spectrometry (SIMS) analyses on two different species of sea urchins. A temperate species of sea urchin (Arbacia punctulata) was cultured at variable pCO2 (400, 600, 900, 2850 ppmv) and at a constant temperature (25°C) [4]. We also investigated a tropical species of sea urchins (Echinometra viridis) that was cultured at variable pCO2 (400 and 1000 ppmv) and variable temperature (20°C and 30°C). The highly porous spines were embedded in epoxy and polished with 3 μm diamond suspension. SIMS analyses were performed with an oxygen primary beam and a lateral spatial resolution of about 40 μm. The standard deviation for SIMS spot analysis of Li in the reference synthetic calcite, CAL-HTP, was 3.5 % (1σ). The standard deviation of SIMS spots analyses of coral reference material M93-TB-FC-1 was 9.5 % (1σ). The bulk B content in this reference coral was determined by LA-ICP-MS as 39.3 ppm [6]. The standard deviation for the SIMS spot analysis of Mg in the reference synthetic calcite, UCI, was 1% (1σ). For the temperate species, B/Ca ratios decrease from ~0.39 to 0.29 mmol/mol as pCO2 increase from 400 to 2850 ppmv. This suggests that B/Ca ratios in this species may be a viable proxy for paleo-seawater pH. Other elements such as Li/Ca showed an increase from .047 to .052 mmol/mol as pCO2 increased. However, Mg/Ca did not show any significant trend as pCO2 increased. The tropical species showed a general increase in Li/Ca, B/Ca, Mg/Ca with increasing temperature. When temperature was held constant, there was no significant effect of

  13. Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4: Calculated dehydrogenation enthalpy, including zero point energy, and the structure of the phonon spectra.

    Science.gov (United States)

    Marashdeh, Ali; Frankcombe, Terry J

    2008-06-21

    The dehydrogenation enthalpies of Ca(AlH(4))(2), CaAlH(5), and CaH(2)+6LiBH(4) have been calculated using density functional theory calculations at the generalized gradient approximation level. Harmonic phonon zero point energy (ZPE) corrections have been included using Parlinski's direct method. The dehydrogenation of Ca(AlH(4))(2) is exothermic, indicating a metastable hydride. Calculations for CaAlH(5) including ZPE effects indicate that it is not stable enough for a hydrogen storage system operating near ambient conditions. The destabilized combination of LiBH(4) with CaH(2) is a promising system after ZPE-corrected enthalpy calculations. The calculations confirm that including ZPE effects in the harmonic approximation for the dehydrogenation of Ca(AlH(4))(2), CaAlH(5), and CaH(2)+6LiBH(4) has a significant effect on the calculated reaction enthalpy. The contribution of ZPE to the dehydrogenation enthalpies of Ca(AlH(4))(2) and CaAlH(5) calculated by the direct method phonon analysis was compared to that calculated by the frozen-phonon method. The crystal structure of CaAlH(5) is presented in the more useful standard setting of P2(1)c symmetry and the phonon density of states of CaAlH(5), significantly different to other common complex metal hydrides, is rationalized.

  14. Primary Ca-rich Carbonate Melts in the Transition Zone

    Science.gov (United States)

    Walter, M.; Bulanova, G.; Armstrong, L.; Keshav, S.; Blundy, J.; Hinton, R.; Lennie, A.

    2007-12-01

    We present new experimental and geochemical constraints on the origin of composite Ca(Ti,Si)O3 and Ca- rich majorite garnet diamond inclusions from Juina kimberlite, Brazil. The evidence reveals that the inclusions did not form as subsolidus minerals, but instead crystallized directly from calcium-rich carbonate melts during crystallization of the host diamond. Subsolidus Phase Relations. We interpret composite CaSiO3 + CaTiO3 inclusions as exsolution products from a single-phase perovskite (Pv) in the transition zone1. The MgSiO3 component in the bulk CaTiSi-Pv is exceedingly low (<0.2 mol%), unlike experimental observations of Ca-Pv coexisting with either majorite-garnet or Mg-Pv (3-7 mol%) in peridotite or eclogite2,3. Indeed, our new subsolidus phase relations show MgSiO3 increasing substantially in Ca-Pv with increasing CaTiO3- content (20-50 GPa, 2000 K). The Ca-content of the majoritic inclusions are exceptionally high (10-15 wt% CaO), also unlike in peridotite or eclogite (< 7%). Unless bizarre mantle lithologies are invoked, subsolidus paragenesis for these inclusions is effectively precluded. Melting Phase Relations. We present new experiments showing that at transition zone depths, primary melts from carbonated eclogite crystallize CaTi-rich perovskites with composition very like the inclusions, and with exceptionally low MgSiO3 (<0.2 mol%). Liquidus majorite is very calcic (10-20 wt% CaO), spanning the range of garnet inclusions. This evidence indicates that the mineral inclusions crystallized from Ca-rich carbonate melts4. Trace Element Modeling. The trace element chemistry of the inclusions as determined using SIMS techniques support a model in which the inclusions equilibrated with small-degree melts. Overall the inclusions are massively enriched in a range of incompatible trace elements, (e.g. 103 to 104 x CI in perovskite). Based on experimental mineral-melt partitioning data, calculated coexisting melts have features inherited from subducted

  15. Polyamine triggering of exocytosis in Paramecium involves an extracellular Ca(2+)/(polyvalent cation)-sensing receptor, subplasmalemmal Ca-store mobilization and store-operated Ca(2+)-influx via unspecific cation channels.

    Science.gov (United States)

    Klauke, N; Blanchard, M; Plattner, H

    2000-03-15

    The polyamine secretagogue, aminoethyldextran (AED), causes a cortical [Ca(2+)] transient in Paramecium cells, as analyzed by fluorochrome imaging. Our most essential findings are: (i) Cortical Ca(2+) signals also occur when AED is applied in presence of the fast Ca(2+) chelator, BAPTA. (ii) Extracellular La(3+) application causes within seconds a rapid, reversible fluorescence signal whose reversibility can be attributed to a physiological [Ca(2+)](i) transient (while injected La(3+) causes a sustained fluorescence signal). (iii) Simply increasing [Ca(2+)](o) causes a similar rapid, short-lived [Ca(2+)](i) transient. All these phenomena, (i-iii), are compatible with activation of an extracellular "Ca(2+)/(polyvalent cation)-sensing receptor" known from some higher eukaryotic systems, where this sensor (responding to Ca(2+), La(3+) and some multiply charged cations) is linked to cortical calcium stores which, thus, are activated. In Paramecium, such subplasmalemmal stores ("alveolar sacs") are physically linked to the cell membrane and they can also be activated by the Ca(2+) releasing agent, 4-chloro-m-cresol, just like in Sarcoplasmic Reticulum. Since this drug causes a cortical Ca(2+) signal also in absence of Ca(2+)(o) we largely exclude a "Ca(2+)-induced Ca(2+) release" (CICR) mechanism. Our finding of increased cortical Ca(2+) signals after store depletion and re-addition of extracellular Ca(2+) can be explained by a "store-operated Ca(2+) influx" (SOC), i.e., a Ca(2+) influx superimposing store activation. AED stimulation in presence of Mn(2+)(o) causes fluorescence quenching in Fura-2 loaded cells, indicating involvement of unspecific cation channels. Such channels, known to occur in Paramecium, share some general characteristics of SOC-type Ca(2+) influx channels. In conclusion, we assume the following sequence of events during AED stimulated exocytosis: (i) activation of an extracellular Ca(2+)/polyamine-sensing receptor, (ii) release of Ca(2+) from

  16. In-situ thermal analysis and macroscopical characterization of Mg-xCa and Mg-0.5Ca-xZn alloy systems

    Energy Technology Data Exchange (ETDEWEB)

    Farahany, Saeed [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Bakhsheshi-Rad, Hamid Reza, E-mail: Rezabakhsheshi@gmail.com [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Idris, Mohd Hasbullah [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Abdul Kadir, Mohammed Rafiq [Medical Implants Technology Group, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Department of Biomechanics and Biomedical Materials, Faculty of Biomedical Engineering and Health Sciences, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Lotfabadi, Amir Fereidouni [Department of Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Ourdjini, Ali [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)

    2012-01-10

    Highlights: Black-Right-Pointing-Pointer The effect of Ca and Zn addition on Mg-Ca and Mg-Ca-Zn were investigated. Black-Right-Pointing-Pointer Ca and Zn addition decreased solid fraction at coherency point. Black-Right-Pointing-Pointer T{sub N}-T{sub DCP} increased by adding Ca and Zn in Mg-Ca and Mg-Ca-Zn, respectively. Black-Right-Pointing-Pointer Three reactions were detected when Zn/Ca atomic ratio less than 1.25 in Mg-Ca-Zn. Black-Right-Pointing-Pointer A new peak Mg{sub 51}Zn{sub 20} was identified in Mg-0.5Ca-9Zn in addition of other peaks. - Abstract: This research described the identification phases by thermal analysis and microscopy inspection of Mg-xCa and Mg-0.5%Ca-xZn alloys that were solidified at slow cooling rate. Analysis of cooling curve after Ca addition shows the evolution of the Mg{sub 2}Ca intermetallic phase at around 520 Degree-Sign C in addition to {alpha}-Mg phase. First derivative curves of alloys after the addition of Zn to Mg-0.5Ca alloy reveals three peaks related to {alpha}-Mg, Mg{sub 2}Ca and Ca{sub 2}Mg{sub 6}Zn{sub 3} for alloys that have Zn/Ca atomic ratio less than 1.23. The peak of Mg{sub 2}Ca reaction on the first derivative curves disappeared for alloys containing Zn/Ca ratio more than 1.23. A new peak was also observed at 330 Degree-Sign C for Mg-0.5Ca-9Zn which was identified as Mg{sub 51}Zn{sub 20}. Solid fraction at coherency point decreased with increasing Ca and Zn elements. However, coherency time and difference between the nucleation and coherency temperatures (T{sub N}-T{sub DCP}) increased by adding Ca and Zn in Mg-Ca and Mg-Ca-Zn systems.

  17. Defect luminescence in CaF{sub 2} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Antonyak, O.T., E-mail: o.antonyak@gmail.com [Ivan Franko National University of Lviv, 8 Kyryla i Mefodiya Street, 79005 Lviv (Ukraine); Vistovskyy, V.V.; Zhyshkovych, A.V. [Ivan Franko National University of Lviv, 8 Kyryla i Mefodiya Street, 79005 Lviv (Ukraine); Kravchuk, I.M. [Lviv Politechnic National University, 12 S. Bandery Street, 79000 Lviv (Ukraine)

    2015-11-15

    The stationary X-ray excited luminescence (XEL) spectra at 80 and 294 K as well as the thermally stimulated luminescence (TSL) in the 80–320 K range of the CaF{sub 2} nanoparticles with various grain sizes (20–60 nm) were studied. Similarly to the earlier studied single CaF{sub 2} crystals, specific bands were revealed both for XEL and for TSL of the radiation defects. XEL spectra of the CaF{sub 2} nanoparticles contain emission bands in the 240–500 nm region caused by excitonic-like excitations localized at the radiation defects of the CaF{sub 2} lattice as well as recombination luminescence band at 560 nm. TSL integral curves of CaF{sub 2} nanoparticles contain peaks that correspond to the delocalization of the hole centers and to their recombination with F-centers and with electronic centers of the cationic sublattice. Activation energies of delocalization processes of the hole centers were determined. It was established that the light output of both XEL and TSL of the CaF{sub 2} nanoparticles increases with an increase of size of nanoparticles in the region of 20–50 nm. - Highlights: • X-ray excited and the thermo stimulated luminescence of CaF{sub 2} nanoparticles were studied. • The specific luminescence bands of the radiation defects were revealed. • Activation energies of delocalization processes of the hole centers were determined. • The dependence of the luminescence output on nanoparticle grain size were established.

  18. The role of the dentate gyrus, CA3a,b, and CA3c for detecting spatial and environmental novelty.

    Science.gov (United States)

    Hunsaker, Michael R; Rosenberg, Jenna S; Kesner, Raymond P

    2008-01-01

    It has been suggested that the dentate gyrus (DG) and CA3 cooperate to efficiently process spatial information. The DG has been proposed to be important for fine spatial discrimination, and the CA3 has been proposed to mediate larger scale spatial information processing. To evaluate the roles of the DG and CA3a,b for spatial processing, we developed a task that measures responses to either overall environmental novelty or a response to more subtle changes within the environment. Animals with lesions to the DG showed impaired novelty detection for both environment as well as smaller changes in the environment, whereas animals with lesions to CA3a,b showed no such deficits. A closer look at the lesions suggested that the CA3 lesions included only CA3a and CA3b, but spared CA3c. To test the role of the spared CA3c region, animals with selective lesions to CA3c that spared CA3a,b were run on the same task and showed an intermediate pattern of deficits. These results suggest that the DG is critical for spatial information processing. These data also suggest that CA3 is a heterogeneous structure, with CA3c lesioned animals showing greater spatial processing deficits than CA3a,b lesioned animals. These findings extend our knowledge of hippocampal function and need to be accounted for in future computational models.

  19. Skeletal muscle Ca(2+)-independent kinase activity increases during either hypertrophy or running

    Science.gov (United States)

    Fluck, M.; Waxham, M. N.; Hamilton, M. T.; Booth, F. W.

    2000-01-01

    Spikes in free Ca(2+) initiate contractions in skeletal muscle cells, but whether and how they might signal to transcription factors in skeletal muscles of living animals is unknown. Since previous studies in non-muscle cells have shown that serum response factor (SRF) protein, a transcription factor, is phosphorylated rapidly by Ca(2+)/calmodulin (CaM)-dependent protein kinase after rises in intracellular Ca(2+), we measured enzymatic activity that phosphorylates SRF (designated SRF kinase activity). Homogenates from 7-day-hypertrophied anterior latissimus dorsi muscles of roosters had more Ca(2+)-independent SRF kinase activity than their respective control muscles. However, no differences were noted in Ca(2+)/CaM-dependent SRF kinase activity between control and trained muscles. To determine whether the Ca(2+)-independent and Ca(2+)/CaM-dependent forms of Ca(2+)/CaM-dependent protein kinase II (CaMKII) might contribute to some of the SRF kinase activity, autocamtide-3, a synthetic substrate that is specific for CaMKII, was employed. While the Ca(2+)-independent form of CaMKII was increased, like the Ca(2+)-independent form of SRF kinase, no alteration in CaMKII occurred at 7 days of stretch overload. These observations suggest that some of SRF phosphorylation by skeletal muscle extracts could be due to CaMKII. To determine whether this adaptation was specific to the exercise type (i.e., hypertrophy), similar measurements were made in the white vastus lateralis muscle of rats that had completed 2 wk of voluntary running. Although Ca(2+)-independent SRF kinase was increased, no alteration occurred in Ca(2+)/CaM-dependent SRF kinase activity. Thus any role of Ca(2+)-independent SRF kinase signaling has downstream modulators specific to the exercise phenotype.

  20. Rapid recycling of Ca2+ between IP3-sensitive stores and lysosomes.

    Directory of Open Access Journals (Sweden)

    Cristina I López Sanjurjo

    Full Text Available Inositol 1,4,5-trisphosphate (IP3 evokes release of Ca2+ from the endoplasmic reticulum (ER, but the resulting Ca2+ signals are shaped by interactions with additional intracellular organelles. Bafilomycin A1, which prevents lysosomal Ca2+ uptake by inhibiting H+ pumping into lysosomes, increased the amplitude of the initial Ca2+ signals evoked by carbachol in human embryonic kidney (HEK cells. Carbachol alone and carbachol in combination with parathyroid hormone (PTH evoke Ca2+ release from distinct IP3-sensitive Ca2+ stores in HEK cells stably expressing human type 1 PTH receptors. Bafilomycin A1 similarly exaggerated the Ca2+ signals evoked by carbachol or carbachol with PTH, indicating that Ca2+ released from distinct IP3-sensitive Ca2+ stores is sequestered by lysosomes. The Ca2+ signals resulting from store-operated Ca2+ entry, whether evoked by thapsigargin or carbachol, were unaffected by bafilomycin A1. Using Gd3+ (1 mM to inhibit both Ca2+ entry and Ca2+ extrusion, HEK cells were repetitively stimulated with carbachol to assess the effectiveness of Ca2+ recycling to the ER after IP3-evoked Ca2+ release. Blocking lysosomal Ca2+ uptake with bafilomycin A1 increased the amplitude of each carbachol-evoked Ca2+ signal without affecting the rate of Ca2+ recycling to the ER. This suggests that Ca2+ accumulated by lysosomes is rapidly returned to the ER. We conclude that lysosomes rapidly, reversibly and selectively accumulate the Ca2+ released by IP3 receptors residing within distinct Ca2+ stores, but not the Ca2+ entering cells via receptor-regulated, store-operated Ca2+ entry pathways.

  1. Distribution of interneurons in the CA2 region of the rat hippocampus.

    Science.gov (United States)

    Botcher, Nicola A; Falck, Joanne E; Thomson, Alex M; Mercer, Audrey

    2014-01-01

    The CA2 region of the mammalian hippocampus is a unique region with its own distinctive properties, inputs and pathologies. Disruption of inhibitory circuits in this region appears to be linked with the pathology of specific psychiatric disorders, promoting interest in its local circuitry, its role in hippocampal function and its dysfunction in disease. In previous studies, CA2 interneurons, including a novel subclass of CA2 dendrite-preferring interneurons that has not been identified in other CA regions, have been shown to display physiological, synaptic and morphological properties unique to this sub-field and may therefore play a crucial role in the hippocampal circuitry. The distributions of immuno-labeled interneurons in dorsal CA2 were studied and compared with those of interneurons in CA1 and CA3. Like those in CA1 and CA3, the somata of CA2 parvalbumin-immunoperoxidase-labeled interneurons were located primarily in Stratum Pyramidale (SP) and Stratum Oriens (SO), with very few cells in Stratum Radiatum (SR) and none in Stratum Lacunosum Moleculare (SLM). There was, however, a greater proportion of GAD-positive cells were immunopositive for PV in SP in CA2 than in CA1 or CA3. CA2 SP also contained a larger density of somatostatin-, calbindin-, and VIP-immunopositive somata than CA1 and/or CA3. Like those in CA1 and CA3, CCK-immunopositive somata in CA2 were mostly located in SR. Reelin- and NPY- immunolabeled cell bodies were located in all layers of the three CA regions. However, a higher density of Reelin-positive somata was found in SP and SR of CA2 than in CA1 or CA3.

  2. Ca2+ paradox injury mediated through TRPC channels in mouse ventricular myocytes.

    Science.gov (United States)

    Kojima, Akiko; Kitagawa, Hirotoshi; Omatsu-Kanbe, Mariko; Matsuura, Hiroshi; Nosaka, Shuichi

    2010-12-01

    BACKGROUND AND PURPOSE The Ca(2+) paradox is an important phenomenon associated with Ca(2+) overload-mediated cellular injury in myocardium. The present study was undertaken to elucidate molecular and cellular mechanisms for the development of the Ca(2+) paradox. EXPERIMENTAL APPROACH Fluorescence imaging was performed on fluo-3 loaded quiescent mouse ventricular myocytes using confocal laser scanning microscope. KEY RESULTS The Ca(2+) paradox was readily evoked by restoration of the extracellular Ca(2+) following 10-20 min of nominally Ca(2+)-free superfusion. The Ca(2+) paradox was significantly reduced by blockers of transient receptor potential canonical (TRPC) channels (2-aminoethoxydiphenyl borate, Gd(3+), La(3+)) and anti-TRPC1 antibody. The sarcoplasmic reticulum (SR) Ca(2+) content, assessed by caffeine application, gradually declined during Ca(2+)-free superfusion, which was further accelerated by metabolic inhibition. Block of SR Ca(2+) leak by tetracaine prevented Ca(2+) paradox. The Na(+) /Ca(2+) exchange (NCX) blocker KB-R7943 significantly inhibited Ca(2+) paradox when applied throughout superfusion period, but had little effect when added for a period of 3 min before and during Ca(2+) restoration. The SR Ca(2+) content was better preserved during Ca(2+) depletion by KB-R7943. Immunocytochemistry confirmed the expression of TRPC1, in addition to TRPC3 and TRPC4, in mouse ventricular myocytes. CONCLUSIONS AND IMPLICATIONS These results provide evidence that (i) the Ca(2+) paradox is primarily mediated by Ca(2+) entry through TRPC (probably TRPC1) channels that are presumably activated by SR Ca(2+) depletion; and (ii) reverse mode NCX contributes little to the Ca(2+) paradox, whereas inhibition of NCX during Ca(2+) depletion improves SR Ca(2+) loading, and is associated with reduced incidence of Ca(2+) paradox in mouse ventricular myocytes.

  3. Safrole-induced cellular Ca2+ increases and death in human osteosarcoma cells.

    Science.gov (United States)

    Lin, Hsueh-Chi; Cheng, He-Hsiung; Huang, Chun-Jen; Chen, Wei-Chuan; Chen, I-Shu; Liu, Shiuh-Inn; Hsu, Shu-Shong; Chang, Hong-Tai; Huang, Jong-Khing; Chen, Jin-Shyr; Lu, Yih-Chau; Jan, Chung-Ren

    2006-08-01

    The effect of the carcinogen safrole on intracellular Ca2+ movement has not been explored in osteoblast-like cells. This study examined whether safrole could alter Ca2+ handling and viability in MG63 human osteosarcoma cells. Cytosolic free Ca2+ levels ([Ca2+]i) in populations of cells were measured using fura-2 as a fluorescent Ca2+ probe. Safrole at concentrations above 130 microM increased [Ca2+]i in a concentration-dependent manner with an EC50 value of 450 microM. The Ca2+ signal was reduced by 30% by removing extracellular Ca2+. Addition of Ca2+ after safrole had depleted intracellular Ca2+ induced Ca2+ influx, suggesting that safrole caused Ca2+ entry. In Ca2+-free medium, after pretreatment with 650 microM safrole, 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor) failed to release more Ca2+; and pretreatment with thapsigargin inhibited most of the safrole-induced [Ca2+]i increases. Inhibition of phospholipase C with U73122 did not affect safrole-induced Ca2+ release; whereas activation of protein kinase C with phorbol ester enhanced safrole-induced [Ca2+]i increase. Trypan exclusion assays revealed that incubation with 65 microM safrole for 30 min did not kill cells, but incubation with 650 microM safrole for 10-30 min nearly killed all cells. Flow cytometry demonstrated that safrole evoked apoptosis in a concentration-dependent manner. Safrole-induced cytotoxicity was not reversed by chelation of Ca2+ with BAPTA. Collectively, the data suggest that in MG63 cells, safrole induced a [Ca2+]i increase by causing Ca2+ release mainly from the endoplasmic reticulum in a phospholipase C-independent manner. The safrole response involved Ca2+ influx and is modulated by protein kinase C. Furthermore, safrole can cause apoptosis in a Ca2+-independent manner.

  4. Clinical Significance and Prognostic Value of CA72-4 Compared with CEA and CA19-9 in Patients with Gastric Cancer

    Directory of Open Access Journals (Sweden)

    M. Ychou

    2000-01-01

    Full Text Available Carcinoembryonic antigen (CEA and CA 19-9 are both widely used in the follow up of patients with gastrointestinal cancer. More recently another tumor marker, named CA 72-4 has been identified and characterized using two different monoclonal antibodies B72.3 and CC49. Several reports evaluated CA 72-4 as a serum tumor marker for gastric cancer and compared its clinical utility with that of CEA or CA 19-9; few reports concerned its prognostic value. In the present study, CA 72-4 is evaluated and compared with CEA and CA 19-9 in various populations of patients with gastric cancer and benign disease; for 52 patients with gastric adenocarcinoma and 57 patients without neoplastic disease CEA, CA 19-9 and CA 72-4 were evaluated before treatment. Sensitivity of the tumor markers CA 72-4, CA 19-9 and CEA at the recommended cut-off level in all 52 patients were 58%, 50% the sensitivity increased to 75%. of these markers, for non metastatic patients, multivariate analyses indicated that none of the markers were significant, when adjusted for gender and age (which were indicators of poor prognosis; patients with abnormal values of CA72-4 tended to have shorter survival than patients with normal values (p < 0.07. In the metastatic population, only high values of CA19-9 (p < 0.02 and gender (women (p < 0.03 were indicators of poor prognosis in univariate analysis; multivariate analysis revealed that both CA72-4 (p = 0.034 and CA19-9 p = 0.009, adjusted for gender were independent prognostic factors. However, CA72-4 lost significance (p = 0.41 when adjusted for CA19-9 and gender, indicating that CA19-9 provides more prognostic information than CA72-4.

  5. Modulation of late sodium current by Ca2+, calmodulin, and CaMKII in normal and failing dog cardiomyocytes: similarities and differences.

    Science.gov (United States)

    Maltsev, Victor A; Reznikov, Vitaliy; Undrovinas, Nidas A; Sabbah, Hani N; Undrovinas, Albertas

    2008-04-01

    Augmented and slowed late Na(+) current (I(NaL)) is implicated in action potential duration variability, early afterdepolarizations, and abnormal Ca(2+) handling in human and canine failing myocardium. Our objective was to study I(NaL) modulation by cytosolic Ca(2+) concentration ([Ca(2+)](i)) in normal and failing ventricular myocytes. Chronic heart failure was produced in 10 dogs by multiple sequential coronary artery microembolizations; 6 normal dogs served as a control. I(NaL) fine structure was measured by whole cell patch clamp in ventricular myocytes and approximated by a sum of fast and slow exponentials produced by burst and late scattered modes of Na(+) channel gating, respectively. I(NaL) greatly enhanced as [Ca(2+)](i) increased from "Ca(2+) free" to 1 microM: its maximum density increased, decay of both exponentials slowed, and the steady-state inactivation (SSI) curve shifted toward more positive potentials. Testing the inhibition of CaMKII and CaM revealed similarities and differences of I(NaL) modulation in failing vs. normal myocytes. Similarities include the following: 1) CaMKII slows I(NaL) decay and decreases the amplitude of fast exponentials, and 2) Ca(2+) shifts SSI rightward. Differences include the following: 1) slowing of I(NaL) by CaMKII is greater, 2) CaM shifts SSI leftward, and 3) Ca(2+) increases the amplitude of slow exponentials. We conclude that Ca(2+)/CaM/CaMKII signaling increases I(NaL) and Na(+) influx in both normal and failing myocytes by slowing inactivation kinetics and shifting SSI. This Na(+) influx provides a novel Ca(2+) positive feedback mechanism (via Na(+)/Ca(2+) exchanger), enhancing contractions at higher beating rates but worsening cardiomyocyte contractile and electrical performance in conditions of poor Ca(2+) handling in heart failure.

  6. Formation Mechanism of CaS-Bearing Inclusions and the Rolling Deformation in Al-Killed, Low-Alloy Steel with Ca Treatment

    Science.gov (United States)

    Xu, Guang; Jiang, Zhouhua; Li, Yang

    2016-08-01

    The existing form of CaS inclusion in Ca-treated, Al-killed steel during secondary refining process was investigated with scanning electron microscopy and an energy-dispersive spectrometer (EDS). The results of 12 heats industrial tests showed that CaS has two kinds of precipitation forms. One form takes place by the direct reaction of Ca and S, and the other takes place by the reaction of CaO in calcium aluminates with dissolved Al and S in liquid steel. Thermodynamic research for different precipitation modes of CaS under different temperature was carried out. In particular, CaO-Al2O3-CaS isothermal section diagrams and component activities of calcium aluminates were calculated by the thermodynamic software FactSage. By thermodynamic calculation, a precipitation-area diagram of oxide-sulfide duplex inclusion was established by fixing the sulfur content. The quantity of CaS, which was precipitated in a reaction between [Al], [S] and (CaO), can be calculated and predicted based on the precipitation-area diagram of oxide-sulfide duplex inclusion. Electron probe microanalysis and EDS were used for observing rolling deformation of different types of CaS-bearing inclusions during the rolling process. Low modification of calcium aluminates wrapped by CaS has different degrees of harm to steel in the rolling process. A thick CaS layer can prevent some fragile calcium aluminates from being crushed during the rolling process. Some oxide-sulfide duplex inclusion contains little CaS performed better deformation during the rolling process, but when CaS in oxide-sulfide duplex inclusion becomes more, it will cause the whole inclusion to lose plastic yielding ability. The plastic deformation region of CaS-bearing inclusion in a CaO-Al2O3-CaS isothermal section diagram is confirmed.

  7. Measurement of the Phase Diagram of the SiO2-CaCl2 System and Liquid Area Study of the SiO2-CaO-CaCl2 System

    Science.gov (United States)

    Wang, Ye; Morita, Kazuki

    2016-06-01

    To optimize the process of boron removal from molten silicon, the slag refining treatment using the CaO-SiO2-CaCl2 slag system has been proven to be effective. However, the phase relations of the SiO2-CaCl2 and CaO-SiO2-CaCl2 systems have not been reported yet. Thus, in this study, the phase diagram of the SiO2-CaCl2 system was determined by using thermogravimetric differential thermal analysis (TG-DTA). Moreover, the liquid area of the CaO-SiO2-CaCl2 ternary system at 1723 K (1450 °C) was also measured by using TG-DTA and morphological observations.

  8. Measurement of intracellular Ca2+ concentration in single cells using ratiometric calcium dyes.

    Science.gov (United States)

    Srikanth, Sonal; Gwack, Yousang

    2013-01-01

    Measurement of intracellular Ca(2+) concentration ([Ca(2+)](i)) is useful to study the upstream and downstream events of Ca(2+) signaling. Ca(2+)-binding proteins including EF-hand-containing proteins are important downstream effector molecules after an increase of [Ca(2+)](i). Conversely, these proteins can also act as key modulators for regulation of [Ca(2+)](i) by sensing the Ca(2+) levels in the intracellular organelles and cytoplasm. Here we describe a single-cell Ca(2+) imaging technique that was used to measure the intracellular Ca(2+) levels to examine the function of Ca(2+)-binding proteins, STIM1 and Calcium release-activated Calcium channel regulator 2A (CRACR2A), using ratiometric Ca(2+) dye Fura-2 in adherent and non-adherent cells.

  9. Sarcoplasmic Reticulum Ca2+ Cycling Protein Phosphorylation in a Physiologic Ca2+ Milieu Unleashes a High-Power, Rhythmic Ca2+ Clock in Ventricular Myocytes: Relevance to Arrhythmias and Bio-Pacemaker Design

    Science.gov (United States)

    Sirenko, Syevda; Maltsev, Victor A; Maltseva, Larissa A; Yang, Dongmei; Lukyanenko, Yevgeniya; Vinogradova, Tatiana; Jones, Larry; Lakatta, Edward G.

    2014-01-01

    Basal phosphorylation of sarcoplasmic reticulum (SR) Ca2+ proteins is high in sinoatrial nodal cells (SANC), which generate partially synchronized, spontaneous, rhythmic, diastolic local Ca2+ releases (LCRs), but low in ventricular myocytes (VM), which exhibit rare diastolic, stochastic SR-generated Ca2+ sparks. We tested the hypothesis that in a physiologic Ca2+ milieu, and independent of increased Ca2+ influx, an increase in basal phosphorylation of SR Ca2+ cycling proteins will convert stochastic Ca2+ sparks into periodic, high-power Ca2+ signals of the type that drives SANC normal automaticity. We measured phosphorylation of SR-associated proteins, phospholamban (PLB) and ryanodine receptors (RyR), and spontaneous local Ca2+ release characteristics (LCR) in permeabilized single, rabbit VM in physiologic [Ca2+], prior to and during inhibition of protein phosphatase (PP) and phosphodiesterase (PDE), or addition of exogenous cAMP, or in the presence of an antibody (2D12), that specifically inhibits binding of the PLB to SERCA-2. In the absence of the aforementioned perturbations, VM could only generate stochastic local Ca2+ releases of low power and low amplitude, as assessed by confocal Ca2+ imaging and spectral analysis. When the kinetics of Ca2+ pumping into the SR were increased by an increase in PLB phosphorylation (via PDE and PP inhibition or addition of cAMP) or by 2D12, self-organized, “clock-like” local Ca2+ releases, partially synchronized in space and time (Ca2+ wavelets), emerged, and the ensemble of these rhythmic local Ca2+ wavelets generated a periodic high-amplitude Ca2+ signal. Thus, a Ca2+ clock is not specific to pacemaker cells, but can also be unleashed in VM when SR Ca2+ cycling increases and spontaneous local Ca2+ release becomes partially synchronized. This unleashed Ca2+ clock that emerges in a physiological Ca2+ milieu in VM has two faces, however: it can provoke ventricular arrhythmias; or if harnessed, can be an important feature

  10. 血清CA15-3、CA50、CA19-9和IL-8检测对女性乳腺癌的诊断价值

    Institute of Scientific and Technical Information of China (English)

    高永旺; 蒋炳辰

    2014-01-01

    Objective:To investigate the clinical signficance of differences on serum CA15-3,CA50,CA19-9,IL-8 levels detection in patients with breast cancer. Methods:Serum CA15-3,CA50,CA19-9,IL-8 concentration from 34 patients (female) with breast cancer and 34 healthy normal controls (female) were determined by RIA and CLIA. Results:The serum CA15-3,CA50,IL-8 levels in patients with breast cancer were significant higher than those in controls. But the serum CA19-9 levels were no significant difference from those in controls.Conclusion:Detection of serum CA15-3,CA50,IL-8 levels might be of prognostic importance in patients with breast cancer.%目的:探讨血清CA15-3、CA50、CA19-9和IL-8检测对乳腺癌患者诊断的临床意义。方法:应用放射免疫法和化学发光法对34例乳腺癌患者(均为女性)进行血清的CA15-3、CA50、CA19-9和IL-8检测,并与34名正常人(均为女性)进行相关对比分析。结果:乳腺癌患者的CA15-3、CA50和IL-8含量水平明显高于对照组(P<0.05),而CA19-9与正常人对照组无明显差异(P>0.05)。结论:血清CA15-3、CA50和IL-8的检测对乳腺癌的发病、预防、诊断和治疗均有重要的临床价值。

  11. Mitochondrial carbonic anhydrase CA VB: Differences in tissue distribution and pattern of evolution from those of CA VA suggest distinct physiological roles

    OpenAIRE

    Shah, Gul N.; Hewett-Emmett, David; Grubb, Jeffrey H.; Migas, Mary C.; Fleming, Robert E.; Waheed, Abdul; Sly, William S.

    2000-01-01

    A cDNA for a second mouse mitochondrial carbonic anhydrase (CA) called CA VB was identified by homology to the previously characterized murine CA V, now called CA VA. The full-length cDNA encodes a 317-aa precursor that contains a 33-aa classical mitochondrial leader sequence. Comparison of products expressed from cDNAs for murine CA VB and CA VA in COS cells revealed that both expressed active CAs that localized in mitochondria, and showed comparable activities in crude extracts and in mitoc...

  12. Dynamics of matrix-free Ca2+ in cardiac mitochondria: two components of Ca2+ uptake and role of phosphate buffering.

    Science.gov (United States)

    Wei, An-Chi; Liu, Ting; Winslow, Raimond L; O'Rourke, Brian

    2012-06-01

    Mitochondrial Ca(2+) uptake is thought to provide an important signal to increase energy production to meet demand but, in excess, can also trigger cell death. The mechanisms defining the relationship between total Ca(2+) uptake, changes in mitochondrial matrix free Ca(2+), and the activation of the mitochondrial permeability transition pore (PTP) are not well understood. We quantitatively measure changes in [Ca(2+)](out) and [Ca(2+)](mito) during Ca(2+) uptake in isolated cardiac mitochondria and identify two components of Ca(2+) influx. [Ca(2+)](mito) recordings revealed that the first, MCU(mode1), required at least 1 µM Ru360 to be completely inhibited, and responded to small Ca(2+) additions in the range of 0.1 to 2 µM with rapid and large changes in [Ca(2+)](mito). The second component, MCU(mode2), was blocked by 100 nM Ru360 and was responsible for the bulk of total Ca(2+) uptake for large Ca(2+) additions in the range of 2 to 10 µM; however, it had little effect on steady-state [Ca(2+)](mito). MCU(mode1) mediates changes in [Ca(2+)](mito) of 10s of μM, even in the presence of 100 nM Ru360, indicating that there is a finite degree of Ca(2+) buffering in the matrix associated with this pathway. In contrast, the much higher Ca(2+) loads evoked by MCU(mode2) activate a secondary dynamic Ca(2+) buffering system consistent with calcium-phosphate complex formation. Increasing P(i) potentiated [Ca(2+)](mito) increases via MCU(mode1) but suppressed [Ca(2+)](mito) changes via MCU(mode2). The results suggest that the role of MCU(mode1) might be to modulate oxidative phosphorylation in response to intracellular Ca(2+) signaling, whereas MCU(mode2) and the dynamic high-capacity Ca(2+) buffering system constitute a Ca(2+) sink function. Interestingly, the trigger for PTP activation is unlikely to be [Ca(2+)](mito) itself but rather a downstream byproduct of total mitochondrial Ca(2+) loading.

  13. CD147 reinforces [Ca2+]i oscillations and promotes oncogenic progression in hepatocellular carcinoma.

    Science.gov (United States)

    Tang, Juan; Guo, Yun-Shan; Yu, Xiao-Ling; Huang, Wan; Zheng, Ming; Zhou, Ying-Hui; Nan, Gang; Wang, Jian-Chao; Yang, Hai-Jiao; Yu, Jing-Min; Jiang, Jian-Li; Chen, Zhi-Nan

    2015-10-27

    Oscillations in intracellular Ca2+ concentrations ([Ca2+]i) mediate various cellular function. Although it is known that [Ca2+]i oscillations are susceptible to dysregulation in tumors, the tumor-specific regulators of [Ca2+]i oscillations are poorly characterized. We discovered that CD147 promotes hepatocellular carcinoma (HCC) metastasis and proliferation by enhancing the amplitude and frequency of [Ca2+]i oscillations in HCC cells. CD147 activates two distinct signaling pathways to regulate [Ca2+]i oscillations. By activating FAK-Src-IP3R1 signaling pathway, CD147 promotes Ca2+ release from endoplasmic reticulum (ER) and enhances the amplitude of [Ca2+]i oscillations. Furthermore, CD147 accelerates ER Ca2+refilling and enhances the frequency of [Ca2+]i oscillations through activating CaMKP-PAK1-PP2A-PLB-SERCA signaling pathway. Besides, CD147-promoted ER Ca2+ release and refilling are tightly regulated by changing [Ca2+]i. CD147 may activate IP3R1 channel under low [Ca2+]i conditions and CD147 may activate SERCA pump under high [Ca2+]i conditions. CD147 deletion suppresses HCC tumorigenesis and increases the survival rate of liver-specific CD147 knockout mice by regulating [Ca2+]i oscillations in vivo. Together, these results reveal that CD147 functions as a critical regulator of ER-dependent [Ca2+]i oscillations to promote oncogenic progression in HCC.

  14. Correlation Between Sunspot Number and ca II K Emission Index

    CERN Document Server

    Bertello, Luca; Tlatov, Andrey; Singh, Jagdev

    2016-01-01

    Long-term synoptic observations in the resonance line of Ca II K constitute a fundamental database for a variety of retrospective analyses of the state of the solar magnetism. Synoptic Ca II K observations began in late 1904 at the Kodaikanal Observatory, in India. In early 1970s, the National Solar Observatory (NSO) at Sacramento Peak (USA) started a new program of daily Sun-as-a-star observations in the Ca II K line. Today the NSO is continuing these observations through its Synoptic Optical Long-term Investigations of the Sun (SOLIS) facility. These different data sets can be combined into a single disk-integrated Ca II K index time series that describes the average properties of the chromospheric emission over several solar cycles. We present such a Ca II K composite and discuss its correlation with the new entirely revised sunspot number data series. For this preliminary investigation, the scaling factor between pairs of time series was determined assuming a simple linear model for the relationship betwe...

  15. Correlation Between Sunspot Number and Ca ii K Emission Index

    Science.gov (United States)

    Bertello, Luca; Pevtsov, Alexei; Tlatov, Andrey; Singh, Jagdev

    2016-11-01

    Long-term synoptic observations in the resonance line of Ca ii K constitute a fundamental database for a variety of retrospective analyses of the state of the solar magnetism. Synoptic Ca ii K observations began in late 1904 at the Kodaikanal Observatory in India. In the early 1970s, the National Solar Observatory (NSO) at Sacramento Peak (USA) started a new program of daily Sun-as-a-star observations in the Ca ii K line. Today the NSO is continuing these observations through its Synoptic Optical Long-term Investigations of the Sun (SOLIS) facility. These different data sets can be combined into a single disk-integrated Ca ii K index time series that describes the average properties of the chromospheric emission over several solar cycles. We present such a Ca ii K composite and discuss its correlation with the new entirely revised sunspot number data series. For this preliminary investigation, the scaling factor between pairs of time series was determined assuming a simple linear model for the relationship between the monthly mean values during the duration of overlapping observations.

  16. Synaptic modulation by astrocytes via Ca2+-dependent glutamate release.

    Science.gov (United States)

    Santello, M; Volterra, A

    2009-01-12

    In the past 15 years the classical view that astrocytes play a relatively passive role in brain function has been overturned and it has become increasingly clear that signaling between neurons and astrocytes may play a crucial role in the information processing that the brain carries out. This new view stems from two seminal observations made in the early 1990s: 1. astrocytes respond to neurotransmitters released during synaptic activity with elevation of their intracellular Ca2+ concentration ([Ca2+]i); 2. astrocytes release chemical transmitters, including glutamate, in response to [Ca2+]i elevations. The simultaneous recognition that astrocytes sense neuronal activity and release neuroactive agents has been instrumental for understanding previously unknown roles of these cells in the control of synapse formation, function and plasticity. These findings open a conceptual revolution, leading to rethink how brain communication works, as they imply that information travels (and is processed) not just in the neuronal circuitry but in an expanded neuron-glia network. In this review we critically discuss the available information concerning: 1. the characteristics of the astrocytic Ca2+ responses to synaptic activity; 2. the basis of Ca2+-dependent glutamate exocytosis from astrocytes; 3. the modes of action of astrocytic glutamate on synaptic function.

  17. Absolute activity determination of CaWO{sub 4} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Muenster, Andrea; Ertl, Andreas; Guetlein, Achim; Lanfranchi, Jean-Come; Potzel, Walter; Roth, Sabine; Simon, Daniel; Scholl, Stephan; Sivers, Moritz von; Strauss, Raimund; Wawoczny, Stephan; Willers, Michael; Wuestrich, Marc; Zoeller, Andreas [TU Muenchen, Fakultaet fuer Physik, E15, Garching (Germany)

    2013-07-01

    The direct Dark Matter search experiment CRESST uses CaWO{sub 4} single crystals as targets for possible WIMP recoils. A particle interaction in the crystal produces phonons as well as scintillation light. As the light signal is dependent on the kind of interacting particle, a particle discrimination on an event-by-event basis is feasible. The observed background is mainly due to intrinsic radioactive impurities of the CaWO{sub 4} target. An activity of this intrinsic contamination can be determined with the investigation of α-decays in the crystal. Up to now, CaWO{sub 4} crystals were produced by suppliers in Russia and Ukraine. Since 2011 we are able to grow CaWO{sub 4} crystals in a Czochralski furnace installed in the crystal laboratory of TU Munich, which has the advantage to better meet the requirements of CRESST and to ensure the availability of CaWO{sub 4} crystals for the successive future multi-material experiment EURECA. To check the radiopurity, first self-grown crystals were investigated in test measurements. In this talk we will present the results for absolute α-activities of self-grown crystals and compare them to α-activities of the crystals installed in the last CRESST run (Run32).

  18. The Infrared Ca II triplet as metallicity indicator

    CERN Document Server

    Carrera, Ricardo; Pancino, Elena; Zinn, Robert

    2007-01-01

    From observations of almost 500 RGB stars in 29 Galactic open and globular clusters, we have investigated the behaviour of the infrared Ca II triplet (8498, 8542 and 8662 \\AA) in the age range 13$\\leq$Age/Gyr$\\leq$0.25 and the metallicity range $-2.2\\leq$ [Fe/H] $\\leq$+0.47. These are the widest ranges of ages and metallicities in which the behaviour of the Ca II triplet lines has been investigated in a homogeneous way. We report the first empirical study of the variation of the CaII triplet lines strength, for given metallicities, with respect to luminosity. We find that the sequence defined by each cluster in the Luminosity-$\\Sigma$Ca plane is not exactly linear. However, when only stars in a small magnitude interval are observed, the sequences can be considered as linear. We have studied the the Ca II triplet lines on three metallicities scales. While a linear correlation between the reduced equivalent width ($W'_V$ or $W'_I$) versus metallicity is found in the \\citet{cg97} and \\citet{ki03} scales, a secon...

  19. Ca2+-CaM系统对野生苦菜耐盐抗氧化系统的调控%Regulation of Ca2+-CaM on Antioxidant System of Salt Tolerance in Sonchus oleraceus L.

    Institute of Scientific and Technical Information of China (English)

    陈贵华; 石岭

    2012-01-01

    用两种从不同位点阻断Ca2+信号途径的抑制剂,即Ca2+螯合剂EGTA(乙二醇双四乙酸)(5 mmol/L)和CaM拮抗剂W7(N-氨乙基-5-氯-1-磺胺酰萘)(0.3 mmol/L),分别处理盐胁迫(0.5 mmol/L)下的野生苦菜幼苗,测定其抗氧化系统中酶的活性,H202、Pro和可溶性蛋白的含量.结果表明,EGTA(5 mmol/L)、W7(0.3 mmol/L)可降低超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性,提高H202的含量,降低Pro和可溶性蛋白的含量,说明Ca2+-CaM系统与野生苦菜耐盐性密切相关.

  20. The contraction of Vorticella in different Ca concentration solutions

    Science.gov (United States)

    Kantha, Deependra; van Winkle, David

    2008-03-01

    The contraction of the stalk of Vorticella Convallaria was studied in media with different concentrations of calcium ion solution. Seven solutions were prepared by adding different amounts of CaCl2 in the range of 0.001M to 0.004M in 0.005M EGTA, 0.1M KCl and 0.02M MOPS. The pH values of the solutions were maintained between 6.7 and 6.9. The contractions were recorded as cines (image sequences) by a Phantom V5 camera (Vision Research) on a bright field microscope with 20X objective, with the image resolution of 256 x 128 pixels at 7000 pictures per second. The change in length of stalk as a function of time was analyzed to compute velocity, acceleration, force and force coefficient. The apparent force coefficient increases linearly with time until the whole stalk is contracting. Considering time dependence of force coefficient, the contracting length is modeled as: [ L(t)=L02[ ( 1+CA )( -C+A2mt )+( 1-CA )( -C-A2mt ) ] ] Where L0 is initial contractile length, C=6πηr, A=√C^2-4mK(t) , η is coefficient of viscosity, m is mass and r is radius of zooid.

  1. Identifying vital effects in Halimeda algae with Ca isotopes

    Directory of Open Access Journals (Sweden)

    C. L. Blättler

    2014-12-01

    Full Text Available Geochemical records of biogenic carbonates provide some of the most valuable records of the geological past, but are often difficult to interpret without a mechanistic understanding of growth processes. In this experimental study, Halimeda algae are used as a test organism to untangle some of the specific factors that influence their skeletal composition, in particular their Ca-isotope composition. Algae were stimulated to precipitate both calcite and aragonite by growth in artificial Cretaceous seawater, resulting in experimental samples with somewhat malformed skeletons. The Ca-isotope fractionation of the algal calcite (−0.6‰ appears to be much smaller than that for the algal aragonite (−1.4‰, similar to the behaviour observed in inorganic precipitates. However, the carbonate from Halimeda has higher Ca-isotope ratios than inorganic forms by approximately 0.25‰, likely because of Rayleigh distillation within the algal intercellular space. In identifying specific vital effects and the magnitude of their influence on Ca-isotope ratios, this study suggests that mineralogy has a first-order control on the marine Ca-isotope cycle.

  2. Stable isotopes, Sr/Ca, and Mg/Ca in biogenic carbonates from Petaluma Marsh, northern California, USA

    Energy Technology Data Exchange (ETDEWEB)

    Ingram, B.L.; De Deckker, P.; Chivas, A.R.; Conrad, M.E.; Byrne, A.R.

    2004-10-19

    Stable isotope ({sup 18}O/{sup 16}O and {sup 13}C/{sup 12}C) and minor-element compositions (Sr/Ca and Mg/Ca ratios) of ostracodes and gastropods separated from marsh sediments from San Francisco Bay, Northern California, were used to reconstruct paleoenvironmental changes in Petaluma Marsh over the past 700 yr. The value of {delta}{sup 18}O in the marsh carbonates reflects changes in freshwater inflow, evaporation, and temperature. Mg/Ca and Sr/Ca in ostracode calcite reflect changes in both freshwater inflow and temperature, although primarily reflect temperature changes in the salinity range of about 10-35 {per_thousand}. Ostracode {delta}{sup 18}O values show a gradual increase by 5 {per_thousand} between 500 yr BR and the present, probably reflecting rising sea level and increased evaporation in the marsh. Superimposed on this trend are higher frequency Mg/Ca and {delta}{sup 18}O variations (3-4 {per_thousand}), probably reflecting changes in freshwater inflow and evaporation. A period of low Mg/Ca occurred between about 100-300 cal yr BP, suggesting wetter and cooler conditions during the Little Ice Age. Higher Mg/Ca ratios occurred 600-700 cal yr BP, indicating drier and warmer conditions during the end of the Medieval Warm Period. Both ostracode and gastropod {delta}{sup 13}C values decrease up-core, reflecting decomposition of marsh vegetation, which changes from C{sub 4} ({delta}{sup 13}C {approx} -12{per_thousand}) to CAM ({delta}{sup 13}C = -26 {per_thousand})-type vegetation over time.

  3. Melamine Alters Glutamatergic Synaptic Transmission of CA3-CA1 Synapses Presynaptically Through Autophagy Activation in the Rat Hippocampus.

    Science.gov (United States)

    Zhang, Hui; Wang, Hui; Xiao, Xi; Zhang, Tao

    2016-01-01

    Melamine is an industrial chemical that can cause central nervous system disorders including excitotoxicity and cognitive impairment. Its illegal use in powdered baby formula was the focus of a milk scandal in China in 2008. One of our previous studies showed that melamine impaired glutamatergic transmission in rat hippocampal CA1 pyramidal cells. However, the underlying mechanism of action of melamine is unclear, and it is unknown if the CA3-CA1 pathway is directly involved. In the present study, a whole-cell patch-clamp technique was employed to investigate the effect of melamine on the hippocampal CA3-CA1 pathway in vitro. Both the evoked excitatory postsynaptic current (eEPSC) and the paired-pulse ratio (PPR) were recorded. Furthermore, we examined whether autophagy was involved in glutamatergic transmission alterations induced by melamine. Our data showed that melamine significantly increased the amplitude of eEPSCs in a dose-dependent manner. Inhibition of the N-methyl-D-aspartic acid receptor did not prevent the increase in eEPSC amplitude. In addition, the PPR was remarkably decreased by a melamine concentration of 5 × 10(-5) g/mL. It was found that autophagy could be activated by melamine and an autophagy inhibitor, 3-MA, prevented the melamine-induced increase in eEPSC amplitude. Overall, our results show that melamine presynaptically alters glutamatergic synaptic transmission of hippocampal CA3-CA1 synapses in vitro and this is likely associated with autophagy alteration.

  4. Crosstalk between mitochondrial and sarcoplasmic reticulum Ca2+ cycling modulates cardiac pacemaker cell automaticity.

    Directory of Open Access Journals (Sweden)

    Yael Yaniv

    Full Text Available BACKGROUND: Mitochondria dynamically buffer cytosolic Ca(2+ in cardiac ventricular cells and this affects the Ca(2+ load of the sarcoplasmic reticulum (SR. In sinoatrial-node cells (SANC the SR generates periodic local, subsarcolemmal Ca(2+ releases (LCRs that depend upon the SR load and are involved in SANC automaticity: LCRs activate an inward Na(+-Ca(2+ exchange current to accelerate the diastolic depolarization, prompting the ensemble of surface membrane ion channels to generate the next action potential (AP. OBJECTIVE: To determine if mitochondrial Ca(2+ (Ca(2+ (m, cytosolic Ca(2+ (Ca(2+ (c-SR-Ca(2+ crosstalk occurs in single rabbit SANC, and how this may relate to SANC normal automaticity. RESULTS: Inhibition of mitochondrial Ca(2+ influx into (Ru360 or Ca(2+ efflux from (CGP-37157 decreased [Ca(2+](m to 80 ± 8% control or increased [Ca(2+](m to 119 ± 7% control, respectively. Concurrent with inhibition of mitochondrial Ca(2+ influx or efflux, the SR Ca(2+ load, and LCR size, duration, amplitude and period (imaged via confocal linescan significantly increased or decreased, respectively. Changes in total ensemble LCR Ca(2+ signal were highly correlated with the change in the SR Ca(2+ load (r(2 = 0.97. Changes in the spontaneous AP cycle length (Ru360, 111 ± 1% control; CGP-37157, 89 ± 2% control in response to changes in [Ca(2+](m were predicted by concurrent changes in LCR period (r(2 = 0.84. CONCLUSION: A change in SANC Ca(2+ (m flux translates into a change in the AP firing rate by effecting changes in Ca(2+ (c and SR Ca(2+ loading, which affects the characteristics of spontaneous SR Ca(2+ release.

  5. Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4: Calculated dehydrogenation enthalpy, including zero point energy, and the structure of the phonon spectra

    NARCIS (Netherlands)

    Marashdeh, A.; Frankcombe, T.J.

    2008-01-01

    The dehydrogenation enthalpies of Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4 have been calculated using density functional theory calculations at the generalized gradient approximation level. Harmonic phonon zero point energy (ZPE) corrections have been included using Parlinski’s direct method. The dehydrog

  6. Nanomolar concentrations of inorganic lead increase Ca2+ efflux and decrease intracellular free Ca2+ ion concentrations in cultured rat hippocampal neurons by a calmodulin-dependent mechanism.

    Science.gov (United States)

    Ferguson, C; Kern, M; Audesirk, G

    2000-06-01

    Inorganic lead (Pb2+) activates calmodulin, which in turn may stimulate many other cellular processes. The plasma membrane Ca2+ ATPase is a calmodulin-stimulated enzyme that plays the major role in regulating the "resting" intracellular free Ca2+ ion concentration, [Ca2+]i. We hypothesized that exposing neurons to low levels of Pb2+ would cause Pb2+ to enter the cytoplasm, and that intracellular Pb2+, by activating calmodulin, would stimulate plasma membrane Ca2+ ATPase activity, thereby increasing Ca2+ extrusion and reducing [Ca2+]i. We used the ratiometric Ca2+ indicator fura-2 to estimate changes in [Ca2+]i. In vitro calibrations of fura-2 with solutions of defined free Ca2+ and free Pb2+ concentrations showed that, at free Ca2+ concentrations from 10 nM to 1000 nM, adding Pb2+ caused either no significant change in the F340/F380 ratio (free Pb2+ concentrations from 100 fM to 1 pM) or increased the F340/F380 ratio (free Pb2+ concentrations from 5 to 50 pM). Therefore, fura-2 should be suitable for estimating Pb2+-induced decreases in [Ca2+]i, but not increases in [Ca2+]i. We exposed cultured embryonic rat hippocampal neurons to 100 nM Pb2+ for periods from 1 hour to 2 days and measured the F340/F380 ratio; the ratio decreased significantly by 9 to 16% at all time points, indicating that Pb2+ exposure decreased [Ca2+]i. In neurons loaded with 45Ca, Pb2+ exposure increased Ca2+ efflux for at least two hours; by 24 hours, Ca2+ efflux returned to control levels. Influx of 45Ca was not altered by Pb2+ exposure. Low concentrations (250 nM) of the calmodulin inhibitor calmidazolium had no effect on either 45Ca efflux or on the F340/F380 ratio in fura-loaded control neurons, but completely eliminated the increase in 45Ca efflux and decrease in F340/F380 ratio in Pb2+-exposed neurons. Zaldoride, another calmodulin inhibitor, also eliminated the decrease in F340/F380 ratio in Pb2+-exposed neurons. We conclude that Pb2+ exposure decreases [Ca2+]i and increases Ca2+ efflux

  7. Transitional function of DG to CA3 in the hippocampus

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Using single cell channel model,the transmission features of CA3-DG network in the hippocampus are investigated.The influence of the stimulation on discharge pattern of pyramidal neurons is analyzed,which shows that it starts with period spiking discharges,followed by period-doubling bifurcation to chaos,and period 3 discharge evolving into chaos,and ultimately a period of bursting discharges.Bv the synaptic model,the CA3.DG network model is constructed,which analyzes the summation of postsynaptic currents in the network,the influence of postsynaptic current on discharge rhythm as well as the mechanism of bursting discharges.The strong capacitv of spatiotemporal encoding in the network indicates the features of CA3 network during the information transmission process in the hippocampus.The modeling result with time delay of the synaptic transmission is in accordance with the experimental phenomena of action potential in the hippocampus.

  8. Spins, moments and charge radii beyond $^{48}$Ca

    CERN Multimedia

    Neyens, G; Rajabali, M M; Hammen, M; Blaum, K; Froemmgen, N E; Garcia ruiz, R F; Kreim, K D; Budincevic, I

    Laser spectroscopy of $^{49-54}$Ca is proposed as a continuation of the experimental theme initiated with IS484 “Ground-state properties of K-isotopes from laser and $\\beta$-NMR spectroscopy” and expanded in INTC-I-117 “Moments, Spins and Charge Radii Beyond $^{48}$Ca.” It is anticipated that the charge radii of these isotopes can show strong evidence for the existence of a sub-shell closure at N=32 and could provide a first tentative investigation into the existence of a shell effect at N=34. Furthermore the proposed experiments will simultaneously provide model-independent measurements of the spins, magnetic moments and quadrupole moments of $^{51,53}$Ca permitting existing and future excitation spectra to be pinned to firm unambiguous ground states.

  9. Structural studies of Ca2+-ATPase ligand and regulatory complexes

    DEFF Research Database (Denmark)

    Drachmann, Nikolaj Düring

    2015-01-01

    against their concentration gradient upon ATP hydrolysis. The ion gradients are used to drive several key cellular processes, like the action potential in nerve tissue, acidification of the gastric juice, cell signalling and muscle contraction. The Ca2+-ATPase is an important part of mammalian cells......The Ca2+-ATPase (sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA is a part of the vital P-type ATPase family, which was first discovered in 1957 by Professor Jens Christian Skou. He was the first to describe the Na+,K+-ATPase and its role in generating the membrane potential across the axonal......, and is expressed in different isoforms with different cellular locations. SERCA1a is mainly expressed in fast twitch muscle tissue, SERCA2a in cardiac tissue, SERCA2b is ubiquitously expressed, while SERCA3 isoforms are co-expressed with SERCA2b in nonmuscular cells. In general, SERCA is responsible for the re...

  10. Ca2+ signaling in pancreatic acinar cells: physiology and pathophysiology

    Directory of Open Access Journals (Sweden)

    O.H. Petersen

    2009-01-01

    Full Text Available The pancreatic acinar cell is a classical model for studies of secretion and signal transduction mechanisms. Because of the extensive endoplasmic reticulum and the large granular compartment, it has been possible - by direct measurements - to obtain considerable insights into intracellular Ca2+ handling under both normal and pathological conditions. Recent studies have also revealed important characteristics of stimulus-secretion coupling mechanisms in isolated human pancreatic acinar cells. The acinar cells are potentially dangerous because of the high intra-granular concentration of proteases, which become inappropriately activated in the human disease acute pancreatitis. This disease is due to toxic Ca2+ signals generated by excessive liberation of Ca2+ from both the endoplasmic reticulum and the secretory granules.

  11. Electrical transport properties of CaB6

    Science.gov (United States)

    Stankiewicz, Jolanta; Sesé, Javier; Balakrishnan, Geetha; Fisk, Zachary

    2014-10-01

    We report results from a systematic electron-transport study in a broad temperature range on 12 CaB6 single crystals. None of the crystals were intentionally doped. The different carrier densities observed presumably arise from slight variations in the Ca:B stoichiometry. In these crystals, the variation of the electrical resistivity and of the Hall effect with temperature can be consistently accounted for by the model we propose, in which B-antisite defects (B atom replacing Ca atom) are "amphoteric." The magnetotransport measurements reveal that most of the samples we have studied are close to a metal-insulator transition at low temperatures. The magnetoresistance changes smoothly from negative—for weakly metallic samples—to positive values—for samples in a localized regime.

  12. CaPiTo: protocol stacks for services

    DEFF Research Database (Denmark)

    Gao, Han; Nielson, Flemming; Nielson, Hanne Riis

    2011-01-01

    CaPiTo allows the modelling of service-oriented applications using process algebras at three levels of abstraction. The abstract level focuses on the key functionality of the services; the plug-in level shows how to obtain security using standardised protocol stacks; finally, the concrete level a...... for ensuring the absence of security flaws. The method used is based on static analysis of the corresponding LySa specifications. We illustrate the development on two industrial case studies; one taken from the banking sector and the other a single sign-on protocol....... allows to consider how security is obtained using asymmetric and symmetric cryptographic primitives. The CaPiTo approach therefore caters for a variety of developers that need to cooperate on designing and implementing service-oriented applications. We show how to formally analyse CaPiTo specifications...

  13. The permanent electric dipole moment of CaOH

    Science.gov (United States)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Steimle, Timothy; Shirley, Jeffrey E.

    1990-01-01

    The X 2 Sigma(+), A 2Pi, and B 2Sigma(+) states of CaOH are characterized theoretically and experimentally, with a focus on the value of the permanent electric dipole moment (mu). Calculations based on SCF and SDCI studies of CaOH (Bauschlicher et al., 1984 and 1986) give mu values of 0.98, 0.49, and 0.11 D for the X, A, and B states, respectively, in good agreement with experiments in which the pure rotational spectra of these states were not detected. Modified Rittner (1951) and ligand-field models of these states are explored in detail, and the applicability of these results to observational searches for CaOH in circumstellar envelopes is indicated.

  14. Scallop DMT functions as a Ca2+ transporter.

    Science.gov (United States)

    Toyohara, Haruhiko; Yamamoto, Sayuri; Hosoi, Masatomi; Takagi, Masaya; Hayashi, Isao; Nakao, Kenji; Kaneko, Shuji

    2005-05-01

    We identified a DMT (divalent metal transporter) homologous protein that functions as a Ca(2+) transporter. Scallop DMT cDNA encodes a 539-amino-acid protein with 12 putative membrane-spanning domains and has a consensus transport motif in the fourth extracellular loop. Since its mRNA is significantly expressed in the gill and intestine, it is assumed that scallop DMT transports Ca(2+) from seawater by the gill and from food by the intestine. Scallop DMT lacks the iron-responsive element commonly found in iron-regulatory proteins, suggesting that it is free of the post-transcriptional regulation from intracellular Fe(2+) concentration. Scallop DMT distinctly functions as a Ca(2+) transporter unlike other DMTs, however, it also transports Fe(2+) and Cd(2+) similar to them.

  15. Evidence of a stable binary CdCa quasicrystalline phase

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Jensen, C.H.; Rasmussen, A.R.;

    2001-01-01

    Quasicrystals with a primitive icosahedral structure and a quasilattice constant of 5.1215 Angstrom have been synthesized in a binary Cd-Ca system. The thermal stability of the quasicrystal has been investigated by in situ high-temperature x-ray powder diffraction using synchrotron radiation. It ....... It is demonstrated that the binary CdCa quasicrystal is thermodynamic stable up to its melting temperature. The linear thermal expansion coefficient of the quasicrystal is 2.765x10(-5) K-1. (C) 2001 American Institute of Physics.......Quasicrystals with a primitive icosahedral structure and a quasilattice constant of 5.1215 Angstrom have been synthesized in a binary Cd-Ca system. The thermal stability of the quasicrystal has been investigated by in situ high-temperature x-ray powder diffraction using synchrotron radiation...

  16. Vibronic spectroscopy of sympathetically cooled CaH$^+$

    CERN Document Server

    Rugango, Rene; Janardan, Smitha; Shu, Gang; Brown, Kenneth R

    2016-01-01

    We report the measurement of the 1$^{1}\\Sigma\\longrightarrow$ 2$^{1}\\Sigma$ transition of CaH$^+$ by resonance-enhanced photodissociation of CaH$^+$ that is co-trapped with laser-cooled Ca$^+$ . We observe four resonances that we assign to transitions from the vibrational $v$=0 ground state to the $v'$=1-4 excited states based on theoretical predictions. A simple theoretical model that assumes instantaneous dissociation after resonant excitation yield results in good agreement with the observed spectral features except for the unobserved $v'$=0 peak. The resolution of our experiment is limited by the mode-locked excitation laser, but this survey spectroscopy enables future rotationally resolved studies with applications in astrochemistry and precision measurement.

  17. NMR determination of the Sternheimer antishielding factor of Ca2+.

    Science.gov (United States)

    Trokiner, A; Bellot, P V; Zhdanov, Y; Yakubovskii, A

    2000-06-01

    The experimental determination of the Sternheimer antishielding factor gamma(infinity) for Ca2+ in a sold material is reported for the first time. The gamma(infinity) value was obtained by comparing the quadrupole frequency measured by 43Ca NMR with the electric field gradient calculated in a frame of the point charge approximation in the high-Tc superconducting compound, Tl0.5Pb0.5Sr2CaCu2O7. The deduced value (gamma(infinity)= -6.1+/-.9) is about one-third of that obtained from the quantum mechanical calculations, whereas in the same sample, the gamma(infinity)value for O2- deduced by the same procedure (gamma(infinity)= -13.7+/-2.0) is very close to the calculated one.

  18. Detailed characterization of the cooperative mechanism of Ca(2+) binding and catalytic activation in the Ca(2+) transport (SERCA) ATPase.

    Science.gov (United States)

    Zhang, Z; Lewis, D; Strock, C; Inesi, G; Nakasako, M; Nomura, H; Toyoshima, C

    2000-08-01

    Expression of heterologous SERCA1a ATPase in Cos-1 cells was optimized to yield levels that account for 10-15% of the microsomal protein, as revealed by protein staining on electrophoretic gels. This high level of expression significantly improved our characterization of mutants, including direct measurements of Ca(2+) binding by the ATPase in the absence of ATP, and measurements of various enzyme functions in the presence of ATP or P(i). Mutational analysis distinguished two groups of amino acids within the transmembrane domain: The first group includes Glu771 (M5), Thr799 (M6), Asp800 (M6), and Glu908 (M8), whose individual mutations totally inhibit binding of the two Ca(2+) required for activation of one ATPase molecule. The second group includes Glu309 (M4) and Asn796 (M6), whose individual or combined mutations inhibit binding of only one and the same Ca(2+). The effects of mutations of these amino acids were interpreted in the light of recent information on the ATPase high-resolution structure, explaining the mechanism of Ca(2+) binding and catalytic activation in terms of two cooperative sites. The Glu771, Thr799, and Asp800 side chains contribute prominently to site 1, together with less prominent contributions by Asn768 and Glu908. The Glu309, Asn796, and Asp800 side chains, as well as the Ala305 (and possibly Val304 and Ile307) carbonyl oxygen, contribute to site 2. Sequential binding begins with Ca(2+) occupancy of site 1, followed by transition to a conformation (E') sensitive to Ca(2+) inhibition of enzyme phosphorylation by P(i), but still unable to utilize ATP. The E' conformation accepts the second Ca(2+) on site 2, producing then a conformation (E' ') which is able to utilize ATP. Mutations of residues (Asp813 and Asp818) in the M6/M7 loop reduce Ca(2+) affinity and catalytic turnover, suggesting a strong influence of this loop on the correct positioning of the M6 helix. Mutation of Asp351 (at the catalytic site within the cytosolic domain

  19. Geoamenazas y vulnerabilidad en Cañas, Guanacaste

    Directory of Open Access Journals (Sweden)

    Sánchez Castillo, Sergio

    2003-09-01

    Full Text Available Este artículo se explica en que consiste el Proyecto Piloto de Geoamenazas y Vulnerabilidad, el cual se desarrolla en el cantón de Cañas. Este proyecto es auspiciado y financiado por diferentes organismos internacionales y su ejecución está a cargo de la Comisión Nacional de Prevención de Riesgos y Atención de Emergencias (CNE. Se presentan los aspectos que propiciaron la escogencia del cantón de Cañas: amenaza sísmica, composición de los suelos, amenaza de inundación, base de datos catastrales en formato digital, Plan Regulador y un Comité Local de Emergencias activo. La metodología utilizada en el proyecto incluyó la aplicación de un censo en el Distrito Central de Cañas y se desarrollaron talleres con expertos internacionales y de instituciones nacionales This articles explains what the Geo Threats and Vulnerability Pilot Project is. This Project is developed in the Cañas canton. It is sponsored and financed by different international organisms and its execution is the responsibility of the National Commission of Risk Prevention and Emergency Response (Comisión Nacional de Prevención de Riesgos y Atención de Emergencias - CNE. It presents the aspects that motivated choosing the canton of Cañas: seismic threat, soil composition, flood threat, digital cadastral data, Regulatory Plan and an active Local Emergency Committee. The methodology used in the Project included a census in the main district of Cañas and the development of workshops with international and national experts

  20. VERTEX: Manganese transport with CaCO 3

    Science.gov (United States)

    Martin, John H.; Knauer, George A.

    1983-04-01

    Manganese transport was studied off central California in August and September 1981 as part of the VERTEX (Vertica l Transport and Exchange) research program. Refractory, leachable, and dissolved Mn fractions associated with particles caught in traps set at 11 depths (50 to 2000 m) were analyzed. Through intentional and unintentional CaCO 3 dissolution 'experiments', it was learned that the weakly leachable Mn was originally in association with the carbonate phase. Adsorption on surfaces rather than absorption in CaCO 3 matrices was indicated by the finding that Mn was not released in proportion to the CaCo 3 dissolved, instead it appeared to keep readsorbing to the dissolving surface. Ultimately, Mn went into solution when the particulate CaCO 3 was essentially depleted, suggesting that sufficient sites for adsorption were no longer available. Manganese fluxes with CaCO 3 were low near the surface (0.1 mg cm -2 ky -1), but increased rapidly in the 50 to 200-m depth interval, and then became more or less constant (1.3 mg cm -2 ky -1 for the remainder of the water column (300 to 2000 m). Rate-of-change estimates indicate that Mn is rapidly scavenged in near-surface waters (-130 ng 1 -1 y -1) and slowly regenerated at depth (2.7 ng 1 -1 y -1) in our near-shore study area. Residence times for dissolved Mn were estimated at 1.2 y for surface waters and 17 y at depth. The implications of Mn transport with CaCO 3 in relation to open-ocean sediment excess Mn are discussed.

  1. Ongoing intrinsic synchronous activity is required for the functional maturation of CA3-CA1 glutamatergic synapses.

    Science.gov (United States)

    Huupponen, Johanna; Molchanova, Svetlana M; Lauri, Sari E; Taira, Tomi

    2013-11-01

    Fine-tuning of synaptic connectivity during development is guided by intrinsic activity of the immature networks characteristically consisting of intermittent bursts of synchronous activity. However, the role of synchronous versus asynchronous activity in synapse maturation in the brain is unclear. Here, we have pharmacologically prevented generation of synchronous activity in the immature rat CA3-CA1 circuitry in a manner that preserves unitary activity. Long-term desynchronization of the network resulted in weakening of AMPA-receptor-mediated glutamatergic transmission in CA1 pyramidal cells. This weakening was dependent on protein phosphatases and mGluR activity, associated with an increase in the proportion of silent synapses and a decrease in the protein levels of GluA4 suggesting postsynaptic mechanisms of expression. The findings demonstrate that synchronous activity in the immature CA3-CA1 circuitry is critical for the induction and maintenance of glutamatergic synapses and underscores the importance of temporal activity patterns in shaping the synaptic circuitry during development.

  2. Effect of sertraline on Ca²⁺ fluxes in rabbit corneal epithelial cells.

    Science.gov (United States)

    Yeh, Jeng-Hsien; Sun, Te-Kung; Chou, Chiang-Ting; Chen, Wei-Chuan; Lee, Jenn-Kuen; Yeh, Hsiao-Chun; Liang, Wei-Zhe; Kuo, Chun-Chi; Shieh, Pochuen; Kuo, Daih-Huang; Jan, Chung-Ren

    2015-04-30

    The effect of sertraline, a selective serotonin reuptake inhibitor (SSRI), on cytosolic free Ca²⁺ concentrations ([Ca²⁺](i)) in a rabbit corneal epithelial cell line (SIRC) is unclear. This study explored whether sertraline changed basal [Ca²⁺](i) levels in suspended SIRC cells by using fura-2 as a Ca²⁺-sensitive fluorescent dye. Sertraline at concentrations between 10-100 μM increased [Ca²⁺](i) in a concentration-dependent manner. The Ca²⁺ signal was reduced by 23% by removing extracellular Ca²⁺. Sertraline induced Mn²⁺ influx, leading to quench of fura-2 fluorescence, suggesting Ca²⁺ influx. This Ca²⁺ influx was inhibited by phospholipase A₂ inhibitor aristolochic acid, but not by store-operated Ca²⁺ channel blockers and protein kinase C/A modulators. In Ca²⁺-free medium, pretreatment with the endoplasmic reticulum Ca²⁺ pump inhibitor thapsigargin, cyclopiazonic acid or 2,5-di-tert-butylhydroquinone greatly inhibited sertraline-induced Ca²⁺ release. Inhibition of phospholipase C with U73122 abolished sertraline-induced [Ca²⁺](i) rise. At concentrations of 5-50 μM, sertraline killed cells in a concentration-dependent manner. The cytotoxic effect of 25 μM sertraline was not reversed by prechelating cytosolic Ca²⁺ with BAPTA/AM. Collectively, in SIRC cells, sertraline induced [Ca²⁺](i) rises by causing phospholipase C-dependent Ca²⁺ release from the endoplasmic reticulum and Ca²⁺ influx via phospholipase A₂-sensitive Ca²⁺ channels. Sertraline-caused cytotoxicity was mediated by Ca²⁺-independent pathways.

  3. CaMKIId overexpression in hypertrophy and heart failure: cellular consequences for excitation-contraction coupling

    Directory of Open Access Journals (Sweden)

    Maier L.S.

    2005-01-01

    Full Text Available Ca/calmodulin-dependent protein kinase IIdelta (CaMKIIdelta is the predominant isoform in the heart. During excitation-contraction coupling (ECC CaMKII phosphorylates several Ca-handling proteins including ryanodine receptors (RyR, phospholamban, and L-type Ca channels. CaMKII expression and activity have been shown to correlate positively with impaired ejection fraction in the myocardium of patients with heart failure and CaMKII has been proposed to be a possible compensatory mechanism to keep hearts from complete failure. However, in addition to these acute effects on ECC, CaMKII was shown to be involved in hypertrophic signaling, termed excitation-transcription coupling (ETC. Thus, animal models have shown that overexpression of nuclear isoform CaMKIIdeltaB can induce myocyte hypertrophy. Recent study from our laboratory has suggested that transgenic overexpression of the cytosolic isoform CaMKIIdeltaC in mice causes severe heart failure with altered intracellular Ca handling and protein expression leading to reduced sarcoplasmic reticulum (SR Ca content. Interestingly, the frequency of diastolic spontaneous SR Ca release events (or opening of RyR was greatly enhanced, demonstrating increased diastolic SR Ca leak. This was attributed to increased CaMKII-dependent RyR phosphorylation, resulting in increased and prolonged openings of RyR since Ca spark frequency could be reduced back to normal levels by CaMKII inhibition. This review focuses on acute and chronic effects of CaMKII in ECC and ETC. In summary, CaMKII overexpression can lead to heart failure and CaMKII-dependent RyR hyperphosphorylation seems to be a novel and important mechanism in ECC due to SR Ca leak which may be important in the pathogenesis of heart failure.

  4. Effects of Time Delay on Intracellular Ca2+ Concentration Oscillations

    Institute of Scientific and Technical Information of China (English)

    YING Yang-Jun; HUANG Zu-Qia

    2001-01-01

    Based on the SS-model [Somogyi R and Stucki J W J. Biol. Chem. 266 (1991) 11 068] for the generation of intracellular Ca2+ concentration oscillations, we consider a time delay for the binding kinetics of the Ca2+ channel and find a significant phenomenon that the oscillation takes two quite different modes when a parameter of the system crosses a threshold. One is a quick oscillation mode and the other is a slow oscillation mode. The oscillation frequencies of these modes differ from each other by more than ten times. The change of oscillation form with parameters and its critical behaviour are illustrated by numerical simulation results.

  5. EST Table: CA946024 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available CA946024 KI000061 10/09/28 87 %/114 aa ref|XP_001983086.1| GG16350 [Drosophila erec.../114 aa ZK131.7#CE03253#WBGene00001887#locus:his-13#histone H3#status:Predicted#UniProt:P08898#protein_id:CA...:AGAP012709 10/09/10 87 %/114 aa gnl|Amel|GB14620-PA 10/09/10 87 %/114 aa gi|91094961|ref|XP_969677.1| PREDICTED: similar to His3:CG31613 CG31613-PA [Tribolium castaneum] FS918947 L9 ...

  6. EST Table: CA946141 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available 71 %/183 aa gnl|Amel|GB15689-PA 10/09/10 73 %/186 aa gi|189235385|ref|XP_969534.2| PREDICTED: similar to conserved hypothetical protein [Tribolium castaneum] CA946141 L9 ... ...CA946141 KI000202 11/12/09 GO hit GO:0005488(binding)|GO:0005515(protein binding)|G...O:0016070(RNA metabolic process) 10/09/28 73 %/186 aa ref|XP_969534.2| PREDICTED: similar to conserved hypothetica...l protein [Tribolium castaneum] 10/08/30 48 %/186 aa FBpp0230852|DvirGJ16435-PA 10/08/28 31 %/194 aa Y

  7. Cell surface topology creates high Ca2+ signalling microdomains

    DEFF Research Database (Denmark)

    Brasen, Jens Christian; Olsen, Lars Folke; Hallett, Maurice B

    2010-01-01

    of a smooth cell surface predicts only moderate localized effects, the more realistic "wrinkled" surface topology predicts that Ca2+ concentrations up to 80 microM can persist within the folds of membranes for significant times. This intra-wrinkle location may account for 5% of the total cell volume. Using...... different geometries of wrinkles, our simulations show that high Ca2+ microdomains will be generated most effectively by long narrow membrane wrinkles of similar dimensions to those found experimentally. This is a new concept which has not previously been considered, but which has ramifications as the intra-wrinkle...

  8. Site Environmental Report for 2014 SNL/CA

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Barbara L. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2015-06-01

    Sandia National Laboratories, California (SNL/CA) is a government-owned/contractoroperated laboratory. Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, manages and operates the laboratory for the Department of Energy’s National Nuclear Security Administration (NNSA). The NNSA Sandia Field Office administers the contract and oversees contractor operations at the site. This Site Environmental Report for 2014 was prepared in accordance with DOE Order 231.1B, Environment, Safety and Health Reporting (DOE 2011d). The report provides a summary of environmental monitoring information and compliance activities that occurred at SNL/CA during calendar year 2014. General site and environmental program information is also included.

  9. CaII Κ Imaging to Understand UV Irradiance Variability

    Indian Academy of Sciences (India)

    R. Kariyappa

    2000-09-01

    To identify and understand the underlying physical mechanisms of total solar and UV irradiance variability and to estimate the contribution of various chromospheric features to UV irradiance, detailed analysis of spatially resolved data is required. The various chromospheric features have been segregated and different parameters have been derived from CaII Κ Spectroheliograms of NSO/Sac Peak and Kodaikanal Observatory and compared with UV irradiance flux measured in MgII h and k lines by NOAA 9 satellite. The important results of this detailed analysis of CaII Κ Images of 1992 together with UV irradiance data will be discussed in this paper.

  10. Isospin dependence of reactions $^{48}$Ca+$^{243-251}$Bk

    CERN Document Server

    Shen, Caiwan; Boilley, Davoid; Kosenko, Grigory; Zhao, Enguang

    2008-01-01

    The fusion process of $^{48}$Ca induced reactions is studied with the two-step model. In this model, the fusion process is devided into two stages: first, the sticking stage where projectile and target come to the touching point over the Coulomb barrier from infinite distance, and second, the formation stage where the di-nucleus formed with projectile and target evolve to form the spherical compound nucleus from the touching point. By the use of the statistical evaporation model, the residue cross sections for different neutron evaporation channels are analyzed. From the results, optimum reactions are given to synthesize $Z$ = 117 element with $^{48}$Ca induced reactions.

  11. Archaeological Study of CA-VEN-110, Ventura, California.

    Science.gov (United States)

    1986-01-01

    more feet and may weigh 500 pounds; it was not recovered at CA-VEN-ll, but did occur at Shisholop and at CA-SBA-l, at Rincon Point. It does enter...Southern California Academy of Sciences vol. 8. 1972 Fish Remains, Primarily Otoliths, From a Coastal Indian Midden (SLO-2) at Diablo Cove, San Luis ...Obispo County, California. In 9000 Years of Prehistory at Diablo Canyon, San Luis Obispo County. California, by Roberta S. Greenwood, pp. 99-120. San Luis

  12. Thapsigargin affinity purification of intracellular P(2A)-type Ca(2+) ATPases

    DEFF Research Database (Denmark)

    Vandecaetsbeek, Ilse; Christensen, Søren Brøgger; Liu, Huizhen

    2011-01-01

    The ubiquitous sarco(endo)plasmic reticulum (SR/ER) Ca(2+) ATPase (SERCA2b) and secretory-pathway Ca(2+) ATPase (SPCA1a) belong both to the P(2A)-type ATPase subgroup of Ca(2+) transporters and play a crucial role in the Ca(2+) homeostasis of respectively the ER and Golgi apparatus...

  13. 76 FR 36148 - Notice of Inventory Completion: Fowler Museum at UCLA, Los Angeles, CA

    Science.gov (United States)

    2011-06-21

    ... National Park Service Notice of Inventory Completion: Fowler Museum at UCLA, Los Angeles, CA AGENCY... UCLA, Box 951549, Los Angeles, CA 90095-1549, telephone (310) 825- 1864. SUPPLEMENTARY INFORMATION... Fowler Museum at UCLA, Los Angeles, CA. The human remain was removed from Humboldt County, CA....

  14. Exchangers man the pumps: Functional interplay between proton pumps and proton-coupled Ca(2+) exchangers

    Science.gov (United States)

    Tonoplast-localised proton-coupled Ca(2+) transporters encoded by cation/H(+) exchanger (CAX) genes play a critical role in sequestering Ca(2+) into the vacuole. These transporters may function in coordination with Ca(2+) release channels, to shape stimulus-induced cytosolic Ca(2+) elevations. Recen...

  15. Renal Ca2+ wasting, hyperabsorption, and reduced bone thickness in mice lacking TRPV5.

    NARCIS (Netherlands)

    Hoenderop, J.G.J.; Leeuwen, J.P.P.M. van; Eerden, B.C. van der; Kersten, F.F.J.; Kemp, J.W.C.M. van der; Merillat, A.M.; Waarsing, J.H.; Rossier, B.C.; Vallon, V.; Hummler, E.; Bindels, R.J.M.

    2003-01-01

    Ca2+ ions play a fundamental role in many cellular processes, and the extracellular concentration of Ca2+ is kept under strict control to allow the proper physiological functions to take place. The kidney, small intestine, and bone determine the Ca2+ flux to the extracellular Ca2+ pool in a concerte

  16. The immunophilin FKBP52 inhibits the activity of the epithelial Ca2+ channel TRPV5

    NARCIS (Netherlands)

    Gkika, D.; Topala, C.N.; Hoenderop, J.G.J.; Bindels, R.J.M.

    2006-01-01

    In the kidney, the epithelial Ca(2+) channel TRPV5 constitutes the apical entry pathway in the process of active Ca(2+) reabsorption. The regulation of Ca(2+) influx through TRPV5 is of crucial importance, because it determines the final amount of Ca(2+) excreted in the urine. The present study iden

  17. 血清CEA、CA199、CA724和EMA联合检测对结肠癌的诊断价值

    Institute of Scientific and Technical Information of China (English)

    陈奇奥; 孙敏; 徐永成

    2009-01-01

    目的 探讨血清CEA、CA199、CA724和EMA联合检测对结肠癌的诊断价值. 方法 选择结肠癌60例,正常对照50例,均采用ELISA夹心法测定. 结果 结肠癌组血清CEA、CA199、CA724、EMA与对照组血清CEA、CA199、CA724、EMA两者具有明显差异(P <0.05).结论 血清CEA、CA199、CA724和EMA联合检测可提高阳性率,对结肠癌有一定的临床辅助诊断价值.

  18. 血清CEA、CA-199、CA-125检测对胃癌诊断价值分析

    Institute of Scientific and Technical Information of China (English)

    邹洪南

    2012-01-01

    目的探讨CEA、CA-199、CA-125检测在胃癌诊断中的应用价值.方法采用电化学发光方法对95的侧胃癌患者检测CEA、CA-199、CA-125.结果胃癌患者血清CEA、CA-199、CA-125阳性率分别为31.7%、43.9%、38.6%.CEA+CA-199+CA-125联合检测阳性率79.9%.结论多项肿癌标志物联检可提高胃癌的阳性检出率.

  19. Ca-rich Ca-Al-oxide, high-temperature-stable sorbents prepared from hydrotalcite precursors: synthesis, characterization, and CO2 capture capacity.

    Science.gov (United States)

    Chang, Po-Hsueh; Chang, Yen-Po; Chen, San-Yuan; Yu, Ching-Tsung; Chyou, Yau-Pin

    2011-12-16

    We present the design and synthesis of Ca-rich Ca-Al-O oxides, with Ca(2+)/Al(3+) ratios of 1:1, 3:1, 5:1, and 7:1, which were prepared by hydrothermal decomposition of coprecipitated hydrotalcite-like Ca-Al-CO(3) precursors, for high-temperature CO(2) adsorption at 500-700 °C. In situ X-ray diffraction measurements indicate that the coprecipitated, Ca-rich, hydrotalcite-like powders with Ca(2+)/Al(3+) ratios of 5:1 and 7:1 contained Ca(OH)(2) and layered double hydroxide (LDH) phases. Upon annealing, LDH was first destroyed at approximately 200 °C to form an amorphous matrix, and then at 450-550 °C, the Ca(OH)(2) phase was converted into a CaO matrix with incorporated Al(3+) to form a homogeneous solid solution without a disrupted lattice structure. CaO nanocrystals were grown by thermal treatment of the weakly crystalline Ca-Al-O oxide matrix. Thermogravimetric analysis indicates that a CO(2) adsorption capacity of approximately 51 wt. % can be obtained from Ca-rich Ca-Al-O oxides prepared by calcination of 7:1 Ca-Al-CO(3) LDH phases at 600-700 °C. Furthermore, a relatively high CO(2) capture capability can be achieved, even with gas flows containing very low CO(2) concentrations (CO(2)/N(2) = 10 %). Approximately 95.6 % of the initial CO(2) adsorption capacity of the adsorbent is retained after 30 cycles of carbonation-calcination. TEM analysis indicates that carbonation-promoted CaCO(3) formation in the Ca-Al-O oxide matrix at 600 °C, but a subsequent desorption in N(2) at 700 °C, caused the formation CaO nanocrystals of approximately 10 nm. The CaO nanocrystals are widely distributed in the weakly crystalline Ca-Al-O oxide matrix and are present during the carbonation-calcination cycles. This demonstrates that Ca-Al-O sorbents that developed through the synthesis and calcination of Ca-rich Ca-Al LDH phases are suitable for long-term cyclic operation in severe temperature environments.

  20. Ca2+ regulation in the absence of the iplA gene product in Dictyostelium discoideum

    Directory of Open Access Journals (Sweden)

    Happle Kathrin

    2005-03-01

    Full Text Available Abstract Background Stimulation of Dictyostelium discoideum with cAMP evokes an elevation of the cytosolic free Ca2+ concentration ([Ca2+]i. The [Ca2+]i-change is composed of liberation of stored Ca2+ and extracellular Ca2+-entry. The significance of the [Ca2+]i-transient for chemotaxis is under debate. Abolition of chemotactic orientation and migration by Ca2+-buffers in the cytosol indicates that a [Ca2+]i-increase is required for chemotaxis. Yet, the iplA- mutant disrupted in a gene bearing similarity to IP3-receptors of higher eukaryotes aggregates despite the absence of a cAMP-induced [Ca2+]i-transient which favours the view that [Ca2+]i-changes are insignificant for chemotaxis. Results We investigated Ca2+-fluxes and the effect of their disturbance on chemotaxis and development of iplA- cells. Differentiation was altered as compared to wild type amoebae and sensitive towards manipulation of the level of stored Ca2+. Chemotaxis was impaired when [Ca2+]i-transients were suppressed by the presence of a Ca2+-chelator in the cytosol of the cells. Analysis of ion fluxes revealed that capacitative Ca2+-entry was fully operative in the mutant. In suspensions of intact and permeabilized cells cAMP elicited extracellular Ca2+-influx and liberation of stored Ca2+, respectively, yet to a lesser extent than in wild type. In suspensions of partially purified storage vesicles ATP-induced Ca2+-uptake and Ca2+-release activated by fatty acids or Ca2+-ATPase inhibitors were similar to wild type. Mn2+-quenching of fura2 fluorescence allows to study Ca2+-influx indirectly and revealed that the responsiveness of mutant cells was shifted to higher concentrations: roughly 100 times more Mn2+ was necessary to observe agonist-induced Mn2+-influx. cAMP evoked a [Ca2+]i-elevation when stores were strongly loaded with Ca2+, again with a similar shift in sensitivity in the mutant. In addition, basal [Ca2+]i was significantly lower in iplA- than in wild type amoebae

  1. The Measurement of 41Ca and Its Application for Cell Messenger

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Ca is an important element in human body. Many diseases relate with Ca in organizations and cells.41Ca (T1/2=1.04×105 a, pure electron capture with emission or Auger electrons and X-rays) is an idealtracer to understand of the mechanism of the disease. The measurement of 41Ca with AMS has been usedfor study of long-term bone resorption, bone resorption in a human, Ca uptake and deposition in heardtissue and skeletal Ca metabolism. Ca2+ in cytoplasm of human cell as a cell messenger plays an important

  2. Nuclear structure of light Ca and heavy Cr isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Buerger, A.

    2007-07-01

    In the present thesis, the shell structure in exotic nuclei has been investigated. The focus of the work was on finding new experimental data in neutron-rich Cr and proton-rich Ca isotopes. The investigation of light Ca isotopes concentrated on the nucleus {sup 36}Ca which was produced in a knockout reaction from a radioactive {sup 37}Ca beam. For {sup 36}Ca, the excitation energy of the first 2{sup +} state has been measured for the first time. Furthermore, momentum distributions were analyzed using a Monte-Carlo simulation of the knockout reaction. This analysis yielded the contributions of neutrons from individual orbitals to the total knockout cross section. In principle, these may be used to calculate spectroscopic factors, but such a calculation is hampered by difficulties of present knockout-reaction models in predicting precise single-particle cross sections. The measured branching ratio to the ground and excited states, on the other hand, is close to the predicted value. A remaining difference might be due to emission of protons which cannot be detected with the present experimental setup. Both the branching ratio and the large excitation energy are compatible with a large N=16 gap in {sup 36}Ca that leads to relatively pure configurations both in the ground state and the excited 2{sup +} state. As a by-product of the experiment, two excitation energies in the T=2 nuclei {sup 32}Ar and {sup 28}S have been confirmed, and two {gamma}-ray transitions have been observed for the first time in {sup 37}Ca. While the mirror energy differences in the T=2 pairs {sup 36}Ca-{sup 36}S, {sup 32}Ar-{sup 32}Si, and {sup 28}S-{sup 28}Mg can be reproduced in shell model calculations using a modified USD interaction, these modifications are not sufficient to explain the mirror energy differences for the pair {sup 37}Ca-{sup 37}Cl. In the heavy Cr isotopes, new experimental evidence for a sub-shell closure at N=32 was found in a measurement of B(E2) values using high

  3. Study on Properties of HDPE/Nano-CaCO3 Composite%HDPE/nano-CaCO3复合材料性能研究

    Institute of Scientific and Technical Information of China (English)

    崔文广; 高岩磊; 刘会茹; 郧海丽

    2012-01-01

    HDPE/nano-CaCO3 composite was prepared by melt blending. The effect of the nano-CaCO3 content on mechanical property of the HDPE/nano-CaCO 3 composite was studied. The dispersion of the nano-CaCOj in HDPE matrix was analyzed by SEM. The results showed that the impact strength and tensile strength of the HDPE/namrCaCO3 composite both increased with the namrCaCO3 content, and then decreased with the nano-CaCOj content, but the flexural modulus of the HDPE/namrCaCO3 composite evidently increased with the nano-CaCO3 content. The dispersion of the nano-CaCO3 in HDPE matrix gradually became bad.%采用熔融共混法制备出了高密度聚乙烯( HDPE)/纳米碳酸钙(nano-CaCO3)复合材料.研究了nano-CaCO3的加入量对复合材料力学性能的影响,利用扫描电镜(SEM)分析了nano-CaCO3在HDPE基体中的分散性.结果表明,随着nano-CaCO3用量的增加,HDPE/nano-CaCO3复合材料的冲击强度和拉伸强度均呈现出先增加后降低的趋势,而弯曲模量呈增加趋势;随着用量的增加,nano-CaCO3在HDPE基体中的分散性逐渐变差.

  4. Study on Properties of PP/Nano-CaCO3 Composite%PP/Nano-CaCO3复合材料性能的研究

    Institute of Scientific and Technical Information of China (English)

    高岩磊; 陈慧; 郧海丽; 崔文广

    2012-01-01

    PP/nano-CaCO3 composite was prepared by melt blending PP with nano-CaCO3. The effect of the nano-CaCO3 content on mechanical property of the PP/nano-CaC03 composite was studied. The dispersion of the nano-CaCO3 in PP matrix was analyzed by SEM. The results show that: with the increase of content of nano-CaCO3, the impact strength and the tensile strength of the PP/nano-CaCO3 composite both increase firstly and then decrease, but the flexural modulus of the PP/nano-CaCO3 composite increase evidently. The dispersion of the nano-CaCO3 in PP matrix gradually becomes bad with the increase of the content of nano-CaCO3.%采用熔融共混法制备出了聚丙烯(PP)/纳米碳酸钙(nano-CaCO3)复合材料,研究了nano-CaCO3的加入量对复合材料力学性能的影响,利用扫描电镜(SEM)分析了nano-CaCO3在PP基体中的分散性.结果表明:随着nano-CaCO3用量的增加,PP/nano-CaCO3复合材料的冲击强度和拉伸强度均呈现出先增加后降低的趋势,而弯曲模量呈增加趋势;随着填加最的增加,nano-CaCO3在PP基体中的分散性逐渐变差.

  5. Symmetric spike timing-dependent plasticity at CA3–CA3 synapses optimizes storage and recall in autoassociative networks

    OpenAIRE

    Mishra, Rajiv K; Kim, Sooyun; Guzman, Segundo J.; Jonas, Peter

    2016-01-01

    CA3–CA3 recurrent excitatory synapses are thought to play a key role in memory storage and pattern completion. Whether the plasticity properties of these synapses are consistent with their proposed network functions remains unclear. Here, we examine the properties of spike timing-dependent plasticity (STDP) at CA3–CA3 synapses. Low-frequency pairing of excitatory postsynaptic potentials (EPSPs) and action potentials (APs) induces long-term potentiation (LTP), independent of temporal order....

  6. An FCCP-sensitive Ca2+ store in bullfrog sympathetic neurons and its participation in stimulus-evoked changes in [Ca2+]i.

    Science.gov (United States)

    Friel, D D; Tsien, R W

    1994-07-01

    This study describes a Ca2+ store in fura-2-loaded bullfrog sympathetic neurons that modulates [Ca2+]i responses elicited by either depolarization or Ca2+ release from a caffeine- and ryanodine-sensitive store. This store is insensitive to caffeine and ryanodine, but is sensitive to the protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP). The FCCP-sensitive store slows both the rise in [Ca2+]i during stimulation (apparently by accumulating Ca2+ from the cytosol) and the recovery following stimulation (by releasing the accumulated Ca2+ into the cytosol). For a fixed level of depolarization, recovery is slowed to an extent that depends on stimulus duration. [Ca2+]i imaging shows that these effects are prominent in the soma but not in growth cones. Ca2+ uptake by the FCCP-sensitive store appears to be strongly [Ca2+]i dependent, since it becomes influential only when [Ca2+]i approaches approximately 500 nM. Therefore, this store may specifically influence [Ca2+]i during moderate and strong stimulation. The effect of the store on responses to depolarization can be accounted for by a simple three-compartment scheme consisting of the extracellular medium, the cytosol, and a single internal store with a [Ca2+]i-dependent uptake mechanism resembling the mitochondrial Ca2+ uniporter. The store's effect on responses to caffeine-induced Ca2+ release can be accounted for by including a second internal compartment to represent the caffeine-sensitive store. While the identity of the FCCP-sensitive store is unknown, its sensitivity to FCCP is consistent with a mitochondrial pool. It is suggested that by modulating the temporal properties of [Ca2+]i following stimulation, the FCCP-sensitive store may influence the degree of activation of intracellular [Ca2+]i-dependent processes.

  7. A sequential vesicle pool model with a single release sensor and a ca(2+)-dependent priming catalyst effectively explains ca(2+)-dependent properties of neurosecretion

    DEFF Research Database (Denmark)

    Walter, Alexander M; da Silva Pinheiro, Paulo César; Verhage, Matthijs;

    2013-01-01

    identified. We here propose a Sequential Pool Model (SPM), assuming a novel Ca(2+)-dependent action: a Ca(2+)-dependent catalyst that accelerates both forward and reverse priming reactions. While both models account for fast fusion from the Readily-Releasable Pool (RRP) under control of synaptotagmin-1...... that the elusive 'alternative Ca(2+) sensor' for slow release might be the upstream priming catalyst, and that a sequential model effectively explains Ca(2+)-dependent properties of secretion without assuming parallel pools or sensors....

  8. Suppression of EGF-induced cell proliferation by the blockade of Ca2+ mobilization and capacitative Ca2+ entry in mouse mammary epithelial cells.

    Science.gov (United States)

    Ichikawa, J; Kiyohara, T

    2001-09-01

    The role of intracellular Ca2+ stores and capacitative Ca2+ entry on EGF-induced cell proliferation was investigated in mouse mammary epithelial cells. We have previously demonstrated that EGF enhances Ca2+ mobilization (release of Ca2+ from intracellular Ca2+ stores) and capacitative Ca2+ entry correlated with cell proliferation in mouse mammary epithelial cells. To confirm their role on EGF-induced cell cycle progression, we studied the effects of 2,5-di-tert-butylhydroquinone (DBHQ), a reversible inhibitor of the Ca2+ pump of intracellular Ca2+ stores, and SK&F 96365, a blocker of capacitative Ca2+ entry, on mitotic activity induced by EGF. Mitotic activity was examined using an antibody to PCNA for immunocytochemistry. SK&F 96365 inhibited capacitative Ca2+ entry in a dose-dependent manner (I50: 1-5 microM). SK&F 96365 also inhibited EGF-induced cell proliferation in the same range of concentration (I50: 1-5 microM). DBHQ suppressed [Ca2+]i response to UTP and thus depleted completely Ca2+ stores at 5 microM. DBHQ also inhibited EGF-induced cell proliferation at an I50 value of approximately 10 microM. The removal of these inhibitors from the culture medium increased the reduced mitotic activity reversibly. Using a fluorescent assay of DNA binding of ethidium bromide, no dead cells were detected in any of the cultures. These results indicate that the inhibitory effects of SK&F 96365 and DBHQ on cell proliferation were due to the inhibition of capacitative Ca2+ entry and Ca2+ mobilization suggesting the importance of capacitative Ca2+ entry and Ca2+ mobilization in the control of EGF-induced cell cycle progression in mouse mammary epithelial cells.

  9. The Change and Implication of p16 Protein in CA and Its Cancerization

    Institute of Scientific and Technical Information of China (English)

    苏向阳; 徐广坤; 苏祖兰; 赖维; 陆春

    2001-01-01

    Objective: To investigate the role and clinical significance of p16 protein in Condyloma Acuminatum (CA) and its cancerization.Methods.. The expression of p16 protein was tested in 33 CA samples and 7 cancerized CA samples by immunohistochemical assays.Results: There was abnormal expression of p16 protein in CA and cancerized CA, mainly major protein expression. The p16 protein expresseed in different locations in different cases was as follows: In basal layer cells in normal cuits; in spinous layer, granular layer and stratum corneum layer cells in CA;in keratin pearl peripheral and spinous layer cells in cancerized CA.Conclusion: There was major expression of p16 protein in CA and cancerized CA, and these protein of the two groups might not naturally be the same. Our study indicated that in clinical practice, when major p16 protein expression in CA occurs, it's risk of cancerization shoud be suspected.

  10. Aberrant Splicing Promotes Proteasomal Degradation of L-type Ca v 1.2 Calcium Channels by Competitive Binding for CaV β Subunits in Cardiac Hypertrophy

    NARCIS (Netherlands)

    Hu, Zhenyu; Wang, Jiong Wei; Yu, Dejie; Soon, Jia Lin; De Kleijn, Dominique P V; Foo, Roger; Liao, Ping; Colecraft, Henry M.; Soong, Tuck Wah

    2016-01-01

    Decreased expression and activity of Ca V1.2 calcium channels has been reported in pressure overload-induced cardiac hypertrophy and heart failure. However, the underlying mechanisms remain unknown. Here we identified in rodents a splice variant of Ca V1.2 channel, named Ca V1.2 e21+22, that contain

  11. Compensatory up-regulation of cardiac SR Ca2+-pump by heat-shock counteracts SR Ca2+-channel activation by ischemia/reperfusion.

    Science.gov (United States)

    O'Brien, P J; Li, G O; Locke, M; Klabunde, R E; Ianuzzo, C D

    1997-08-01

    We tested the hypothesis that heat-shock protected myocardial Ca2+-cycling by sarcoplasmic reticulum from ischemia and reperfusion (I/R) injury. Twenty-four hours after increasing body temperature to 42 degrees C for 15 min, rat hearts were isolated, Langendorff-perfused, and subjected to 30 min ischemia then 30 min reperfusion. Left ventricles were homogenized and their ionized Ca2+ concentration monitored with indo- during Ca2+-uptake in the presence and absence of the Ca2+-release channel (CRC) modulator ryanodine. Tissue content of heat-shock protein 72 (HSP 72) was analyzed. Exposure to I/R resulted in a 37% enhancement of CRC activity but no effect on Ca2+-pumping activity, resulting in 25% decreased net Ca2+-uptake activity. Pre-exposure to heat-shock resulted in a 10-fold increase in HSP 72, and a 25% enhancement of maximal Ca2+-pumping activity which counteracted the effect of I/R on CRC and net Ca2+-uptake activities. This protection of SR Ca2+-cycling was associated with partial protection of myocardial physiological performance. Net Ca2+-uptake activity was correlated with the left ventricular developed pressure and its rate of change. We conclude that one of the mechanisms by which heat-shock protects myocardium from I/R injury is to upregulate SR Ca2+-pumping activity to counteract the enhanced SR Ca2+-release produced by I/R.

  12. Low temperature synthesis of CaZrO3 nanoceramics from CaCl2–NaCl molten eutectic salt

    Directory of Open Access Journals (Sweden)

    Rahman Fazli

    2015-06-01

    Full Text Available CaZrO3 nanoceramics were successfully synthesized at 700 C using the molten salt method, and the effects of processing parameters, such as temperature, holding time, and amount of salt on the crystallization of CaZrO3 were investigated. CaCl2, Na2CO3, and nano-ZrO2 were used as starting materials. On heating, CaCl2–NaCl molten eutectic salt provided a liquid medium for the reaction of CaCO3 and ZrO2 to form CaZrO3. The results demonstrated that CaZrO3 started to form at about 600C and that, after the temperature was increased to 1,000C, the amounts of CaZrO3 in the resultant powders increased with a concomitant decrease in CaCO3and ZrO2 contents. After washing with hot distilled water, the samples heated for 3 h at 700C were single-phase CaZrO3 with 90–95 nm particle size. Furthermore, the synthesized CaZrO3 particles retained the size and morphology of the ZrO2 powders which indicated that a template mechanism dominated the formation of CaZrO3 by molten-salt method.

  13. A nicardipine-sensitive Ca2+ entry contributes to the hypotonicity-induced increase in [Ca2+]i of principal cells in rat cortical collecting duct.

    Science.gov (United States)

    Komagiri, You; Nakamura, Kazuyoshi; Kubokawa, Manabu

    2011-01-01

    We examined the mechanisms involved in the [Ca(2+)](i) response to the extracellular hypotonicity in the principal cells of freshly isolated rat cortical collecting duct (CCD), using Fura-2/AM fluorescence imaging. Reduction of extracellular osmolality from 305 (control) to 195 mosmol/kgH(2)O (hypotonic) evoked transient increase in [Ca(2+)](i) of principal cells of rat CCDs. The [Ca(2+)](i) increase was markedly attenuated by the removal of extracellular Ca(2+)(.) The application of a P(2) purinoceptor antagonist, suramin failed to inhibit the hypotonicity-induced [Ca(2+)](i) increase. The [Ca(2+)](i) increase in response to extracellular hypotonicity was not influenced by application of Gd(3+) and ruthenium red. On the other hand, a voltage-gated Ca(2+) channel inhibitor, nicardipine, significantly reduced the peak amplitude of [Ca(2+)](i) increase in the principal cells. In order to assess Ca(2+) entry during the hypotonic stimulation, we measured the quenching of Fura-2 fluorescence intensity by Mn(2+). The hypotonic stimulation enhanced quenching of Fura-2 fluorescence by Mn(2+), indicating that a Ca(2+)-permeable pathway was activated by the hypotonicity. The hypotonicity-mediated enhancement of Mn(2+) quenching was significantly inhibited by nicardipine. These results strongly suggested that a nicardipine-sensitive Ca(2+) entry pathway would contribute to the mechanisms underlying the hypotonicity-induced [Ca(2+)](i) elevation of principal cells in rat CCD.

  14. Crocin, a carotenoid component of Crocus cativus, exerts inhibitory effects on L-type Ca(2+) current, Ca(2+) transient, and contractility in rat ventricular myocytes.

    Science.gov (United States)

    Liu, Tao; Chu, Xi; Wang, Hua; Zhang, Xuan; Zhang, Yuanyuan; Guo, Hui; Liu, Zhenyi; Dong, Yongsheng; Liu, Hongying; Liu, Yang; Chu, Li; Zhang, Jianping

    2016-03-01

    Crocin, a carotenoid component of Crocus sativus L. belonging to the Iridaceae family, has demonstrated cardioprotective effects. To investigate the cellular mechanisms of these cardioprotective effects, here we studied the influence of crocin on L-type Ca(2+)current (I(Ca-L)), intracellular Ca(2+) ([Ca(2+)]i), and contraction of isolated rat cardiomyocytes by using the whole-cell patch-clamp technique and video-based edge detection and dual excitation fluorescence photomultiplier systems. Crocin inhibited I(Ca-L) in a concentration-dependent manner with the half-maximal inhibitory concentration (IC50) of 45 μmol/L and the maximal inhibitory effect of 72.195% ± 1.54%. Neither current-voltage relationship of I(Ca-L), reversal potential of I(Ca-L), nor the activation/inactivation of I(Ca-L) was significantly changed. Crocin at 1 μmol/L reduced cell shortening by 44.64% ± 2.12% and the peak value of the Ca(2+) transient by 23.66% ± 4.52%. Crocin significantly reduced amplitudes of myocyte shortening and [Ca(2+)]i with an increase in the time to reach 10% of the peak (Tp) and a decrease in the time to 10% of the baseline (Tr). Thus, the cardioprotective effects of crocin may be attributed to the attenuation of [Ca(2+)]i through the inhibition of I(Ca-L) in rat cardiomyocytes and negative inotropic effects on myocardial contractility.

  15. Is otolith microchemistry (Sr: Ca and Ba:Ca ratios useful to identify Mugil curema populations in the southeastern Caribbean Sea?

    Directory of Open Access Journals (Sweden)

    E. Avigliano

    Full Text Available Abstract The aim of the present study was to evaluate the potential use of otolith microchemistry (Sr:Ca and Ba:Ca ratios to identify silver mullet, Mugil curema, populations in Southeastern Caribbean Sea. Fish samples were collected in 7 areas of Nueva Esparta State (Venezuela. The otolith Sr:Ca and Ba:Ca ratios and water Sr:Ca were determined (by ICP-OES and EDTA volumetric method. Otoliths Sr:Ca and Ba:Ca ratios and Sr:Ca partition coefficient of mullets in Cubagua island (south of the State were significantly different from ratios in La Guardia (north of the State. A discriminant analysis of otolith Sr:Ca and Ba:Ca ratios separated Cubagua Island from La Guardia values. These results suggest the existence of different mullet groups in the Southeastern Caribbean Sea. For this, the simultaneous use of Sr:Ca and Ba:Ca ratios could be a potential tool to identify populations in the study area.

  16. Punta Pitt Stable Isotope and Ion Data (delta 18O, delta 13C, Cd/Ca, Mn/Ca) for 1936 to 1982.5

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — File contains data presented by Shen et al. (1992a). Table includes d18O, d13C, Cd/Ca, Mn/Ca, and Ba/Ca data from a 2m coral head and, for comparison, SST records...

  17. The carcinogen safrole increases intracellular free Ca2+ levels and causes death in MDCK cells.

    Science.gov (United States)

    Chen, Wei-Chuan; Cheng, He-Hsiung; Huang, Chun-Jen; Lu, Yih-Chau; Chen, I-Shu; Liu, Shiuh-Inn; Hsu, Shu-Shong; Chang, Hong-Tai; Huang, Jong-Khing; Chen, Jin-Shyr; Jan, Chung-Ren

    2007-02-28

    The effect of the carcinogen safrole on intracellular Ca2+ movement in renal tubular cells has not been explored previously. The present study examined whether safrole could alter Ca2+ handling in Madin-Darby canine kidney (MDCK) cells. Cytosolic free Ca2+ levels ([Ca2+]i) in populations of cells were measured using fura-2 as a fluorescent Ca2+ probe. Safrole at concentrations above 33 microM increased [Ca2+]i in a concentration-dependent manner with an EC50 value of 400 microM. The Ca2+ signal was reduced by 90% by removing extracellular Ca2+, but was not affected by nifedipine, verapamil, or diltiazem. Addition of Ca2+ after safrole had depleted intracellular Ca(2+)-induced dramatic Ca2+ influx, suggesting that safrole caused store-operated Ca2+ entry. In Ca(2+)-free medium, after pretreatment with 650 microM safrole, 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor) failed to release more Ca 2+. Inhibition of phospholipase C with 2 microM U73122 did not affect safrole-induced Ca2+ release. Trypan blue exclusion assays revealed that incubation with 650 microM safrole for 30 min did not kill cells, but killed 70% of cells after incubation for 60 min. Collectively, the data suggest that in MDCK cells, safrole induced a [Ca2+] increase by causing Ca2+ release from the endoplasmic reticulum in a phospholipase C-independent fashion, and by inducing Ca2+ influx via store-operated Ca2+ entry. Furthermore, safrole can cause acute toxicity to MDCK cells.

  18. Absence of correlation between ACh-induced Ca influx and phosphatidic acid labeling in rat uterus.

    Science.gov (United States)

    Ichida, S; Moriyama, M; Hirooka, Y; Okazaki, Y; Yoshioka, K

    1984-11-27

    Rat uterine smooth muscle was preincubated in Ca-depleted modified Locke-Ringer solution to investigate the correlation between the 32Pi incorporation into phosphatidic acid induced by acetylcholine and the contractile response to acetylcholine induced by the addition of CaCl2 (Ca influx). The results showed that in rat uterine smooth muscle under these conditions phosphatidic acid does not act as a Ca ionophore or as a trigger for opening the Ca channel.

  19. The self-consistent analysis for sub-barrier fusion enhancement effect in Ca + Ca and Ni + Ni

    CERN Document Server

    Ma, N R; Lin, C J; Yang, L; Xu, X X; Sun, L J; Yang, F; Wu, Z D; Zhang, H Q; Liu, Z H; Wang, D X

    2016-01-01

    The fusion dynamic mechanism of heavy-ions at energies near the Coulomb barrier is complicated and still not very clear up to now. Accordingly, a self-consistent method based on the CCFULL calculations has been developed and applied for an ingoing study of the effect of the positive Q-value neutron transfer (PQNT) channels in this work. The typical experimental fusion data of Ca + Ca and Ni + Ni is analyzed within the unified calculation scheme. The PQNT effect in near-barrier fusion is further confirmed based on the self-consistent analysis and extracted quantitatively.

  20. The functional genome of CA1 and CA3 neurons under native conditions and in response to ischemia

    Directory of Open Access Journals (Sweden)

    Rossner Moritz

    2007-10-01

    Full Text Available Abstract Background The different physiological repertoire of CA3 and CA1 neurons in the hippocampus, as well as their differing behaviour after noxious stimuli are ultimately based upon differences in the expressed genome. We have compared CA3 and CA1 gene expression in the uninjured brain, and after cerebral ischemia using laser microdissection (LMD, RNA amplification, and array hybridization. Results Profiling in CA1 vs. CA3 under normoxic conditions detected more than 1000 differentially expressed genes that belong to different, physiologically relevant gene ontology groups in both cell types. The comparison of each region under normoxic and ischemic conditions revealed more than 5000 ischemia-regulated genes for each individual cell type. Surprisingly, there was a high co-regulation in both regions. In the ischemic state, only about 100 genes were found to be differentially expressed in CA3 and CA1. The majority of these genes were also different in the native state. A minority of interesting genes (e.g. inhibinbetaA displayed divergent expression preference under native and ischemic conditions with partially opposing directions of regulation in both cell types. Conclusion The differences found in two morphologically very similar cell types situated next to each other in the CNS are large providing a rational basis for physiological differences. Unexpectedly, the genomic response to ischemia is highly similar in these two neuron types, leading to a substantial attenuation of functional genomic differences in these two cell types. Also, the majority of changes that exist in the ischemic state are not generated de novo by the ischemic stimulus, but are preexistant from the genomic repertoire in the native situation. This unexpected influence of a strong noxious stimulus on cell-specific gene expression differences can be explained by the activation of a cell-type independent conserved gene-expression program. Our data generate both novel