Science.gov

Sample records for events precede calcium

  1. Kickoff to Conflict: A Sequence Analysis of Intra-State Conflict-Preceding Event Structures

    PubMed Central

    D'Orazio, Vito; Yonamine, James E.

    2015-01-01

    While many studies have suggested or assumed that the periods preceding the onset of intra-state conflict are similar across time and space, few have empirically tested this proposition. Using the Integrated Crisis Early Warning System's domestic event data in Asia from 1998–2010, we subject this proposition to empirical analysis. We code the similarity of government-rebel interactions in sequences preceding the onset of intra-state conflict to those preceding further periods of peace using three different metrics: Euclidean, Levenshtein, and mutual information. These scores are then used as predictors in a bivariate logistic regression to forecast whether we are likely to observe conflict in neither, one, or both of the states. We find that our model accurately classifies cases where both sequences precede peace, but struggles to distinguish between cases in which one sequence escalates to conflict and where both sequences escalate to conflict. These findings empirically suggest that generalizable patterns exist between event sequences that precede peace. PMID:25951105

  2. Patterns of Life Events Preceding the Suicide in Rural Young Chinese: A Case Control Study1

    PubMed Central

    Zhang, Jie; Ma, Zhenyu

    2012-01-01

    Background Previous studies on the Chinese suicide found some life events prior to the suicide different from those in the West, but there is a lack of summary of the Chinese life event patterns to better understand the effects of the social structure on Chinese suicide. Aim We tried to identify the life events that precede the Chinese rural youth suicides and compare them with what found in the West, so as to find the patterns that are particularly true in the Chinese culture contexts. Methods Suicide cases were investigated with a psychological autopsy study in rural China, and local community living controls were also interviewed with the same protocol. Results We collapsed 64 negative life events into six categories: (1) Marriage/Love, (2) Family/Home, (3) Work/Business, (4) Health/Hospital, (5) Law/Legal, (6) Friend/Relationship. About 92.3% of the suicides studied had experienced at least one type of negative life events. The three most common negative life events categories in the past one year were Family/Home (60.7%), Health/Hospital (53.8%) and Marriage/Love (51.3%) in the rural young suicide victims. Conclusions Among the negative life events, those related to family relations, love affairs, and marital issues were most likely to precede a suicide of rural suicides in China, and it is especially true of rural young women. Family is an important social institution in rural China for suicide prevention efforts. PMID:22595373

  3. Intense foreshocks and a slow slip event preceded the 2014 Iquique Mw 8.1 earthquake.

    PubMed

    Ruiz, S; Metois, M; Fuenzalida, A; Ruiz, J; Leyton, F; Grandin, R; Vigny, C; Madariaga, R; Campos, J

    2014-09-01

    The subduction zone in northern Chile is a well-identified seismic gap that last ruptured in 1877. The moment magnitude (Mw) 8.1 Iquique earthquake of 1 April 2014 broke a highly coupled portion of this gap. To understand the seismicity preceding this event, we studied the location and mechanisms of the foreshocks and computed Global Positioning System (GPS) time series at stations located on shore. Seismicity off the coast of Iquique started to increase in January 2014. After 16 March, several Mw > 6 events occurred near the low-coupled zone. These events migrated northward for ~50 kilometers until the 1 April earthquake occurred. On 16 March, on-shore continuous GPS stations detected a westward motion that we model as a slow slip event situated in the same area where the mainshock occurred. PMID:25061132

  4. Helix A Stabilization Precedes Amino-terminal Lobe Activation upon Calcium Binding to Calmodulin

    SciTech Connect

    Chen, Baowei; Lowry, David; Mayer, M. Uljana; Squier, Thomas C.

    2008-08-09

    The structural coupling between opposing domains of CaM was investigated using the conformationally sensitive biarsenical probe 4,5-bis(1,3,2-dithioarsolan-2-yl)-resorufin (ReAsH), which upon binding to an engineered tetracysteine binding motif near the end of helix A (Thr-5 to Phe-19) becomes highly fluorescent. Changes in conformation and dynamics are reflective of the native CaM structure, as there is no change in the 1H-15N HSQC NMR spectrum in comparison to wild-type CaM. We find evidence of a conformational intermediate associated with CaM activation, where calcium occupancy of sites in the amino-terminal and carboxyl-terminal lobes of CaM differentially affect the fluorescence intensity of bound ReAsH. Insight into the structure of the conformational intermediate is possible from a consideration of calcium-dependent changes in rates of ReAsH binding and helix A mobility, which respectively distinguish secondary structural changes associated with helix A stabilization from the tertiary structural reorganization of the amino-terminal lobe of CaM necessary for high-affinity binding to target proteins. Helix A stabilization is associated with calcium occupancy of sites in the carboxyl-terminal lobe (Kd = 0.36 ± 0.04 μM), which results in a reduction in the rate of ReAsH binding from 4900 M-1 sec-1 to 370 M-1 sec-1. In comparison, tertiary structural changes involving helix A and other structural elements in the amino-terminal lobe requires calcium-occupancy of amino-terminal sites (Kd = 18 ± 3 μM). Observed secondary and tertiary structural changes involving helix A in response to the sequential calcium occupancy of carboxyl- and amino-terminal lobe calcium binding sites suggest an important involvement of helix A in mediating the structural coupling between the opposing domains of CaM. These results are discussed in terms of a model in which carboxyl-terminal lobe calcium activation induces

  5. Automated Discovery and Modeling of Sequential Patterns Preceding Events of Interest

    NASA Technical Reports Server (NTRS)

    Rohloff, Kurt

    2010-01-01

    The integration of emerging data manipulation technologies has enabled a paradigm shift in practitioners' abilities to understand and anticipate events of interest in complex systems. Example events of interest include outbreaks of socio-political violence in nation-states. Rather than relying on human-centric modeling efforts that are limited by the availability of SMEs, automated data processing technologies has enabled the development of innovative automated complex system modeling and predictive analysis technologies. We introduce one such emerging modeling technology - the sequential pattern methodology. We have applied the sequential pattern methodology to automatically identify patterns of observed behavior that precede outbreaks of socio-political violence such as riots, rebellions and coups in nation-states. The sequential pattern methodology is a groundbreaking approach to automated complex system model discovery because it generates easily interpretable patterns based on direct observations of sampled factor data for a deeper understanding of societal behaviors that is tolerant of observation noise and missing data. The discovered patterns are simple to interpret and mimic human's identifications of observed trends in temporal data. Discovered patterns also provide an automated forecasting ability: we discuss an example of using discovered patterns coupled with a rich data environment to forecast various types of socio-political violence in nation-states.

  6. Seagrass proliferation precedes mortality during hypo-salinity events: a stress-induced morphometric response.

    PubMed

    Collier, Catherine J; Villacorta-Rath, Cecilia; van Dijk, Kor-jent; Takahashi, Miwa; Waycott, Michelle

    2014-01-01

    Halophytes, such as seagrasses, predominantly form habitats in coastal and estuarine areas. These habitats can be seasonally exposed to hypo-salinity events during watershed runoff exposing them to dramatic salinity shifts and osmotic shock. The manifestation of this osmotic shock on seagrass morphology and phenology was tested in three Indo-Pacific seagrass species, Halophila ovalis, Halodule uninervis and Zostera muelleri, to hypo-salinity ranging from 3 to 36 PSU at 3 PSU increments for 10 weeks. All three species had broad salinity tolerance but demonstrated a moderate hypo-salinity stress response--analogous to a stress induced morphometric response (SIMR). Shoot proliferation occurred at salinities <30 PSU, with the largest increases, up to 400% increase in shoot density, occurring at the sub-lethal salinities <15 PSU, with the specific salinity associated with peak shoot density being variable among species. Resources were not diverted away from leaf growth or shoot development to support the new shoot production. However, at sub-lethal salinities where shoots proliferated, flowering was severely reduced for H. ovalis, the only species to flower during this experiment, demonstrating a diversion of resources away from sexual reproduction to support the investment in new shoots. This SIMR response preceded mortality, which occurred at 3 PSU for H. ovalis and 6 PSU for H. uninervis, while complete mortality was not reached for Z. muelleri. This is the first study to identify a SIMR in seagrasses, being detectable due to the fine resolution of salinity treatments tested. The detection of SIMR demonstrates the need for caution in interpreting in-situ changes in shoot density as shoot proliferation could be interpreted as a healthy or positive plant response to environmental conditions, when in fact it could signal pre-mortality stress.

  7. Seagrass Proliferation Precedes Mortality during Hypo-Salinity Events: A Stress-Induced Morphometric Response

    PubMed Central

    Collier, Catherine J.; Villacorta-Rath, Cecilia; van Dijk, Kor-jent; Takahashi, Miwa; Waycott, Michelle

    2014-01-01

    Halophytes, such as seagrasses, predominantly form habitats in coastal and estuarine areas. These habitats can be seasonally exposed to hypo-salinity events during watershed runoff exposing them to dramatic salinity shifts and osmotic shock. The manifestation of this osmotic shock on seagrass morphology and phenology was tested in three Indo-Pacific seagrass species, Halophila ovalis, Halodule uninervis and Zostera muelleri, to hypo-salinity ranging from 3 to 36 PSU at 3 PSU increments for 10 weeks. All three species had broad salinity tolerance but demonstrated a moderate hypo-salinity stress response – analogous to a stress induced morphometric response (SIMR). Shoot proliferation occurred at salinities <30 PSU, with the largest increases, up to 400% increase in shoot density, occurring at the sub-lethal salinities <15 PSU, with the specific salinity associated with peak shoot density being variable among species. Resources were not diverted away from leaf growth or shoot development to support the new shoot production. However, at sub-lethal salinities where shoots proliferated, flowering was severely reduced for H. ovalis, the only species to flower during this experiment, demonstrating a diversion of resources away from sexual reproduction to support the investment in new shoots. This SIMR response preceded mortality, which occurred at 3 PSU for H. ovalis and 6 PSU for H. uninervis, while complete mortality was not reached for Z. muelleri. This is the first study to identify a SIMR in seagrasses, being detectable due to the fine resolution of salinity treatments tested. The detection of SIMR demonstrates the need for caution in interpreting in-situ changes in shoot density as shoot proliferation could be interpreted as a healthy or positive plant response to environmental conditions, when in fact it could signal pre-mortality stress. PMID:24705377

  8. Seagrass proliferation precedes mortality during hypo-salinity events: a stress-induced morphometric response.

    PubMed

    Collier, Catherine J; Villacorta-Rath, Cecilia; van Dijk, Kor-jent; Takahashi, Miwa; Waycott, Michelle

    2014-01-01

    Halophytes, such as seagrasses, predominantly form habitats in coastal and estuarine areas. These habitats can be seasonally exposed to hypo-salinity events during watershed runoff exposing them to dramatic salinity shifts and osmotic shock. The manifestation of this osmotic shock on seagrass morphology and phenology was tested in three Indo-Pacific seagrass species, Halophila ovalis, Halodule uninervis and Zostera muelleri, to hypo-salinity ranging from 3 to 36 PSU at 3 PSU increments for 10 weeks. All three species had broad salinity tolerance but demonstrated a moderate hypo-salinity stress response--analogous to a stress induced morphometric response (SIMR). Shoot proliferation occurred at salinities <30 PSU, with the largest increases, up to 400% increase in shoot density, occurring at the sub-lethal salinities <15 PSU, with the specific salinity associated with peak shoot density being variable among species. Resources were not diverted away from leaf growth or shoot development to support the new shoot production. However, at sub-lethal salinities where shoots proliferated, flowering was severely reduced for H. ovalis, the only species to flower during this experiment, demonstrating a diversion of resources away from sexual reproduction to support the investment in new shoots. This SIMR response preceded mortality, which occurred at 3 PSU for H. ovalis and 6 PSU for H. uninervis, while complete mortality was not reached for Z. muelleri. This is the first study to identify a SIMR in seagrasses, being detectable due to the fine resolution of salinity treatments tested. The detection of SIMR demonstrates the need for caution in interpreting in-situ changes in shoot density as shoot proliferation could be interpreted as a healthy or positive plant response to environmental conditions, when in fact it could signal pre-mortality stress. PMID:24705377

  9. Stressful life events preceding the acute onset of schizophrenia: a cross-national study from the World Health Organization.

    PubMed

    Day, R; Nielsen, J A; Korten, A; Ernberg, G; Dube, K C; Gebhart, J; Jablensky, A; Leon, C; Marsella, A; Olatawura, M

    1987-06-01

    This study reports on the findings from a WHO sponsored cross-national investigation of life events and schizophrenia. Data are presented from a series of 386 acutely ill schizophrenic patients selected from nine field research centers located in developing and developed countries (Aarhus, Denmark; Agra, India; Cali, Colombia; Chandigarh, India; Honolulu, USA; Ibadan, Nigeria; Nagasaki, Japan; Prague, Czechoslovakia; Rochester, USA). On a methodological level, the study demonstrates that life event methodologies originating in the developed countries can be adapted for international studies and may be used to collect reasonably reliable and comparable cross-cultural data on psychosocial factors affecting the course of schizophrenic disorders. Substantive findings replicate the results of prior studies which conclude that socioenvironmental stressors may precipitate schizophrenic attacks and such events tend to cluster in the two to three week period immediately preceding illness onset.

  10. Survey of DMSP Charging Events During the Period Preceding Cycle 23 Solar Maximum

    NASA Technical Reports Server (NTRS)

    Parker, Linda Neergaard; Minow, Joseph I.

    2013-01-01

    It has been well established that POLAR orbiting satellites can see mild to severe charging levels during solar minimum conditions (Frooninckx and Sojka, 1992, Anderson and Koons, 1996, Anderson, 2012). However, spacecraft operations during solar maximum cannot be considered safe from auroral charging. Recently, we have seen examples of high level charging during the recent approach to solar maximum. We present here a survey of charging events seen by the Defense Meteorological Satellite Program (DMSP) satellites (F16, F17) during the solstices of 2011 and 2012. In this survey, we summarize the condition necessary for charging to occur in this environment, we describe how the lower than normal maximum conditions are conducive to the environment conditions necessary for charging in the POLAR orbit, and we show examples of the more extreme charging events, sometimes exceeding 1 kV, during this time period. We also show examples of other interesting phenomenological events seen in the DMSP data, but which are not considered surface charging events, and discuss the differences.

  11. Brain structural correlates of obsessive-compulsive disorder with and without preceding stressful life events.

    PubMed

    Real, E; Subirà, M; Alonso, P; Segalàs, C; Labad, J; Orfila, C; López-Solà, C; Martínez-Zalacaín, I; Via, E; Cardoner, N; Jiménez-Murcia, S; Soriano-Mas, C; Menchón, J M

    2016-08-01

    Objectives There is growing evidence supporting a role for stressful life events (SLEs) at obsessive-compulsive disorder (OCD) onset, but neurobiological correlates of such effect are not known. We evaluated regional grey matter (GM) changes associated with the presence/absence of SLEs at OCD onset. Methods One hundred and twenty-four OCD patients and 112 healthy controls were recruited. Patients were split into two groups according to the presence (n = 56) or absence (n = 68) of SLEs at disorder's onset. A structural magnetic resonance image was acquired for each participant and pre-processed with Statistical Parametric Mapping software (SPM8) to obtain a volume-modulated GM map. Between-group differences in sociodemographic, clinical and whole-brain regional GM volumes were assessed. Results SLEs were associated with female sex, later age at disorder's onset, more contamination/cleaning and less hoarding symptoms. In comparison with controls, patients without SLEs showed GM volume increases in bilateral dorsal putamen and the central tegmental tract of the brainstem. By contrast, patients with SLEs showed specific GM volume increases in the right anterior cerebellum. Conclusions Our findings support the idea that neuroanatomical alterations of OCD patients partially depend on the presence of SLEs at disorder's onset. PMID:26784523

  12. Event-related power modulations of brain activity preceding visually guided saccades.

    PubMed

    Brignani, Debora; Maioli, Claudio; Maria Rossini, Paolo; Miniussi, Carlo

    2007-03-01

    To analyze the characteristics of the event-related desynchronization (ERD) and synchronization (ERS) of cortical rhythms during the preparation and execution of a lateralized eye movement, EEG was recorded in normal subjects during a visually guided task. Alpha and beta bands were investigated in three temporal intervals: a sensory period, a delay period and a saccade preparation period time locked with saccade onset. Modulations of ERD/ERS power, coupled with the task, reached the largest amplitudes over the frontal and parieto-occipital regions. Differences of oscillatory activity in the alpha bands revealed an intriguing pattern of asymmetry in parieto-occipital areas. Rightward saccades induced a larger desynchronization with respect to the leftward saccades in the left hemisphere, but not in the right. If representative, these findings are congruent to the established right-hemisphere dominance of the brain areas that direct attention. Moreover differences between the two alpha types emerged in the frontal areas before and during the saccade preparation periods, indicative of differential engagement of these areas depending on the task demands. In conclusion, the present approach shows that planning eye movements is linked with covert orienting of spatial attention and may supply a useful method for studying eye movements and selective attention-related processes. PMID:17196943

  13. TP53 mutations are early events in chronic lymphocytic leukemia disease progression and precede evolution to complex karyotypes.

    PubMed

    Lazarian, Gregory; Tausch, Eugen; Eclache, Virginie; Sebaa, Amel; Bianchi, Vincent; Letestu, Remi; Collon, Jean-Francois; Lefebvre, Valerie; Gardano, Laura; Varin-Blank, Nadine; Soussi, Thierry; Stilgenbauer, Stephen; Cymbalista, Florence; Baran-Marszak, Fanny

    2016-10-15

    TP53 abnormalities lead to resistance to purine analogues and are found in over 40% of patients with refractory chronic lymphocytic leukemia (CLL). At diagnosis, no more than 5% of patients carry the 17p deletion, most cases harbour mutations within the other TP53 allele. The incidence of a TP53 mutation as the only alteration is approximately 5%, but this depends on the sensitivity of the technique. Recently, having a complex karyotype has been considered a strong adverse prognostic factor. However, there are no longitudinal studies simultaneously examining the presence of the 17p deletion, TP53 mutations and karyotype abnormalities. We conducted a retrospective longitudinal study of 31 relapsed/refractory CLL patients. Two to six blood samples per patient were analyzed, with a median follow-up of 8 years. In this report, we assessed the sequence of events of TP53 clonal evolution and correlated the presence of TP53 abnormalities to genetic instability during progression and treatment. Next-generation sequencing allowed the early detection of TP53 mutated clones and was able to be performed on a routine basis, demonstrating an excellent correlation between the Illumina and Ion Torrent technologies. We concluded that TP53 mutations are early events and precede clonal evolution to complex karyotypes. We strongly recommend the early and iterated detection of TP53 mutations in progressive cases. PMID:27270786

  14. Calcium utilization by quail embryos during activities preceding space flight and during embryogenesis in microgravity aboard the orbital space station MIR.

    PubMed

    Orban, J I; Piert, S J; Guryeva, T S; Hester, P Y

    1999-10-01

    A series of studies were conducted to determine the effect of activities preceding spaceflight and during space-flight on calcium utilization during quail embryonic development. In the pre-space trials, fertile quail eggs were subjected to pre-flight dynamics including forces of centrifugation, vibration, or a combination of vibration and centrifugation prior to incubation for 6 or 16 days. Quail eggs were also tested for survivability in a refrigerator stowage kit for eggs (RSKE) which was subsequently used to transport the eggs to space. Eggs in the RSKE were subjected to shuttle launch dynamics including G force and random vibration profiles. The space-flight trial involved 48 quail eggs launched on space shuttle Flight STS-76 which were subsequently incubated in a Slovakian incubator onboard space station, MIR. Two ground control trials, each with 48 eggs with and without exposure to shuttle launch dynamics were initiated 5 days post-launch. Eggshells from all study trials were retrieved and analyzed for calcium content. Results showed that neither pre-flight activities nor shuttle launch dynamics had an effect on calcium utilization by developing embryos. However, calcium utilization by developing embryos incubated in microgravity was impaired by 12.6% when compared to embryos incubated on earth under laboratory control environment. This impairment was believed to be due to unidentified factors of the microgravity environment.

  15. Drop in endo/sarcoplasmic calcium precedes the unfolded protein response in Brefeldin A-treated vascular smooth muscle cells.

    PubMed

    Ziomek, Gabriela; van Breemen, Cornelis; Esfandiarei, Mitra

    2015-10-01

    The present study addresses the causal relationship between induction of endo/sarcoplasmic reticulum stress and dysregulation of calcium transport, while examining whether the most widely-used experimental endo/sarcoplasmic reticulum stressors can be considered appropriate for elucidating underlying cellular mechanisms involved during the progression of the unfolded protein response in vascular smooth muscle cells. Brefeldin A is most commonly cited as inducing the stress response through an accumulation of unfolded proteins in the lumen as a result of a blockage of protein transport from the endo/sarcoplasmic reticulum to the Golgi apparatus. We investigated the effects of Brefeldin A on cellular calcium regulation during the the unfolded protein response in cultured rat vascular smooth muscle cells. Acute exposure of cells to Brefeldin A caused a small transient increase in cytoplasmic calcium, which did not cause a significant decrease in endo/sarcoplasmic reticulum calcium content. However, over the time course of 0-12 h post-treatment with Brefeldin A, we observed that the endo/sarcoplasmic reticulum of vascular smooth muscle cells exhibited an approximate fifty percent decrease in calcium concentration after the first hour of exposure, which is maintained over the next eleven hours, whereas concentrations of unfolded protein response markers only began to increase significantly around nine to twelve hours post-treatment. We have concluded that the endo/sarcoplasmic reticulum calcium drop, which up to now, has been considered as a characteristic of the late onset of cellular stress response, occurs prior to the initiation of the unfolded protein response, rather than as a result of its many corrective pathways.

  16. Localised calcium release events in cells from the muscle of guinea-pig gastric fundus

    PubMed Central

    Parsons, S P; Bolton, T B

    2004-01-01

    After enzymatic dispersion of the muscle of the guinea-pig gastric fundus, single elongated cells were observed which differed from archetypal smooth muscle cells due to their knurled, tuberose or otherwise irregular surface morphology. These, but not archetypal smooth muscle cells, consistently displayed spontaneous localized (i.e. non-propagating) intracellular calcium ([Ca2+]i) release events. Such calcium events were novel in their magnitude and kinetic profiles. They included short transient events, plateau events and events which coalesced spatially or temporally (compound events). Quantitative analysis of the events with an automatic detection programme showed that their spatio-temporal characteristics (full width and full duration at half-maximum amplitude) were approximately exponentially distributed. Their amplitude distribution suggested the presence of two release modes. Carbachol application caused an initial cell-wide calcium transient followed by an increase in localized calcium release events. Pharmacological analysis suggested that localized calcium release was largely dependent on external calcium entry acting on both inositol trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs) to release stored calcium. Nominally calcium-free external solution immediately and reversibly abolished all localized calcium release without blocking the initial transient calcium release response to carbachol. This was inhibited by 2-APB (100 μm), ryanodine (10 or 50 μm) or U-73122 (1 μm). 2-APB (100 μm), xestospongin C (XeC, 10 μm) or U-73122 (1 μm) blocked both spontaneous localized calcium release and localized release stimulated by 10 μm carbachol. Ryanodine (50 μm) also inhibited spontaneous release, but enhanced localized release in response to carbachol. This study represents the first characterization of localized calcium release events in cells from the gastric fundus. PMID:14608011

  17. Recent Life Events Preceding Suicide Attempts in a Personality Disorder Sample: Findings from the Collaborative Longitudinal Personality Disorders Study

    ERIC Educational Resources Information Center

    Yen, Shirley; Pagano, Maria E.; Shea, Tracie M.; Grilo, Carlos M.; Gunderson, John G.; Skodol, Andrew E.; McGlashan, Thomas H.; Sanislow, Charles A.; Bender, Donna S.

    2005-01-01

    Few studies have examined the relationship between life events, suicide attempts, and personality disorders (PDs), in spite of the strong associations between PDs and suicidal behavior, and the poor coping strategies often exhibited by these individuals. The authors examined whether participants with PDs who attempted suicide during the first 3…

  18. Does calcium intake affect cardiovascular risk factors and/or events?

    PubMed Central

    Torres, Márcia Regina Simas Gonçalves; Sanjuliani, Antonio Felipe

    2012-01-01

    Dietary intervention is an important approach in the prevention of cardiovascular disease. Over the last decade, some studies have suggested that a calcium-rich diet could help to control body weight, with anti-obesity effects. The potential mechanism underlying the impact of calcium on body fat has been investigated, but it is not fully understood. Recent evidence has also suggested that a calcium-rich diet could have beneficial effects on other cardiovascular risk factors, such as insulin resistance, dyslipidemia, hypertension and inflammatory states. In a series of studies, it was observed that a high intake of milk and/or dairy products (the main sources of dietary calcium) is associated with a reduction in the relative risk of cardiovascular disease. However, a few studies suggest that supplemental calcium (mainly calcium carbonate or citrate) may be associated with an increased risk of cardiovascular events. This review will discuss the available evidence regarding the relationship between calcium intake (dietary and supplemental) and different cardiovascular risk factors and/or events. PMID:22892932

  19. Cytosolic calcium rises and related events in ergosterol-treated Nicotiana cells.

    PubMed

    Vatsa, Parul; Chiltz, Annick; Luini, Estelle; Vandelle, Elodie; Pugin, Alain; Roblin, Gabriel

    2011-07-01

    The typical fungal membrane component ergosterol was previously shown to trigger defence responses and protect plants against pathogens. Most of the elicitors mobilize the second messenger calcium, to trigger plant defences. We checked the involvement of calcium in response to ergosterol using Nicotiana plumbaginifolia and Nicotiana tabacum cv Xanthi cells expressing apoaequorin in the cytosol. First, it was verified if ergosterol was efficient in these cells inducing modifications of proton fluxes and increased expression of defence-related genes. Then, it was shown that ergosterol induced a rapid and transient biphasic increase of free [Ca²⁺](cyt) which intensity depends on ergosterol concentration in the range 0.002-10 μM. Among sterols, this calcium mobilization was specific for ergosterol and, ergosterol-induced pH and [Ca²⁺](cyt) changes were specifically desensitized after two subsequent applications of ergosterol. Specific modulators allowed elucidating some events in the signalling pathway triggered by ergosterol. The action of BAPTA, LaCl₃, nifedipine, verapamil, neomycin, U73122 and ruthenium red suggested that the first phase was linked to calcium influx from external medium which subsequently triggered the second phase linked to calcium release from internal stores. The calcium influx and the [Ca²⁺](cyt) increase depended on upstream protein phosphorylation. The extracellular alkalinization and ROS production depended on calcium influx but, the ergosterol-induced MAPK activation was calcium-independent. ROS were not involved in cytosolic calcium rise as described in other models, indicating that ROS do not systematically participate in the amplification of calcium signalling. Interestingly, ergosterol-induced ROS production is not linked to cell death and ergosterol does not induce any calcium elevation in the nucleus.

  20. Preceding seismic activity and slow slip events in the source area of the 2011 Mw 9.0 Tohoku-Oki earthquake: a review

    NASA Astrophysics Data System (ADS)

    Hasegawa, Akira; Yoshida, Keisuke

    2015-12-01

    The 2011 Tohoku-Oki earthquake ruptured a large area of the megathrust east of NE Japan. The earthquake's magnitude was 9.0, substantially larger than predicted. It is important to know what occurred in the source area prior to this great megathrust earthquake to improve understanding of the nucleation processes of large earthquakes and risk assessments in subduction zones. Seafloor observation data revealed the existence of two extremely large slip patches: one just updip of the mainshock hypocenter and the other 80-100 km to the north near the trench axis. For 70-90 years before 2003, M > 6 events and slips of M > c. 7 events on the megathrust occurred in the areas surrounding these two large slip patches. Seismic activity had increased since at least 2003 in the downdip portion of the source area of the Tohoku-Oki earthquake. In addition, long-term accelerated slow slip occurred in this downdip portion of the source area in the decades before the Tohoku-Oki earthquake. About 1 month before the earthquake, a slow slip event (SSE) took place at relatively shallow depths between the two large slip patches, accompanied by foreshock activity. Both the slow slip and foreshocks propagated from north to south toward the southern large slip patch. Two days before the earthquake, an M 7.3 foreshock and an associated postseismic slip began at relatively deep depths in the megathrust between the two large slip patches. In addition, a slow slip type event seems to have occurred approximately half a day after the M 7.3 foreshock near the mainshock hypocenter. This slow slip event and the foreshock activity again propagated from north to south toward the mainshock hypocenter. These long- and short-term preceding seismic and aseismic slip gradually reduced the interplate coupling, increased shear stresses at the two large slip patches (i.e., two strong asperity patches), and finally led to the rupture of the great Tohoku-Oki earthquake.

  1. Low-risk lifestyle, coronary calcium, cardiovascular events, and mortality: results from MESA.

    PubMed

    Ahmed, Haitham M; Blaha, Michael J; Nasir, Khurram; Jones, Steven R; Rivera, Juan J; Agatston, Arthur; Blankstein, Ron; Wong, Nathan D; Lakoski, Susan; Budoff, Matthew J; Burke, Gregory L; Sibley, Christopher T; Ouyang, Pamela; Blumenthal, Roger S

    2013-07-01

    Unhealthy lifestyle habits are a major contributor to coronary artery disease. The purpose of the present study was to investigate the associations of smoking, weight maintenance, physical activity, and diet with coronary calcium, cardiovascular events, and mortality. US participants who were 44-84 years of age (n = 6,229) were followed in the Multi-Ethnic Study of Atherosclerosis from 2000 to 2010. A lifestyle score ranging from 0 to 4 was created using diet, exercise, body mass index, and smoking status. Coronary calcium was measured at baseline and a mean of 3.1 (standard deviation, 1.3) years later to assess calcium progression. Participants who experienced coronary events or died were followed for a median of 7.6 (standard deviation, 1.5) years. Participants with lifestyle scores of 1, 2, 3, and 4 were found to have mean adjusted annual calcium progressions that were 3.5 (95% confidence interval (CI): 0.0, 7.0), 4.2 (95% CI: 0.6, 7.9), 6.8 (95% CI: 2.0, 11.5), and 11.1 (95% CI: 2.2, 20.1) points per year slower, respectively, relative to the reference group (P = 0.003). Unadjusted hazard ratios for death by lifestyle score were as follows: for a score of 1, the hazard ratio was 0.79 (95% CI: 0.61, 1.03); for a score of 2, the hazard ratio was 0.61 (95% CI: 0.46, 0.81); for a score of 3, the hazard ratio was 0.49 (95% CI: 0.32, 0.75); and for a score of 4, the hazard ratio was 0.19 (95% CI: 0.05, 0.75) (P < 0.001 by log-rank test). In conclusion, a combination of regular exercise, healthy diet, smoking avoidance, and weight maintenance was associated with lower coronary calcium incidence, slower calcium progression, and lower all-cause mortality over 7.6 years.

  2. Calcium

    MedlinePlus

    ... milligrams) of calcium each day. Get it from: Dairy products. Low-fat milk, yogurt, cheese, and cottage ... lactase that helps digest the sugar (lactose) in dairy products, and may have gas, bloating, cramps, or ...

  3. Calcium

    MedlinePlus

    ... supplements and fortified foods include gluconate, lactate, and phosphate. Calcium absorption is best when a person consumes ... also interfere with the body's ability to absorb iron and zinc, but this effect is not well ...

  4. Calcium.

    PubMed

    Williams, Robert J P

    2002-01-01

    This chapter describes the chemical and biological value of the calcium ion. In calcium chemistry, our main interest is in equilibria within static, nonflowing systems. Hence, we examined the way calcium formed precipitates and complex ions in solution. We observed thereafter its uses by humankind in a vast number of materials such as minerals, e.g., marble, concrete, mortars, which parallel the biological use in shells and bones. In complex formation, we noted that many combinations were of anion interaction with calcium for example in the uses of detergents and medicines. The rates of exchange of calcium from bound states were noted but they had little application. Calcium ions do not act as catalysts of organic reactions. In biological systems, interest is in the above chemistry, but extends to the fact that Ca2+ ions can carry information by flowing in one solution or from one solution to another through membranes. Hence, we became interested in the details of rates of calcium exchange. The fast exchange of this divalent ion from most organic binding sites has allowed it to develop as the dominant second messenger. Now the flow can be examined in vitro as calcium binds particular isolated proteins, which it activates as seen in physical mechanical changes or chemical changes and this piece-by-piece study of cells is common. Here, however, we have chosen to stress the whole circuit of Ca2+ action indicating that the cell is organized both at a basal and an activated state kinetic level by the steady state flow of the ion (see Fig. 11). Different time constants of exchange utilizing very similar binding constants lead to: 1) fast responses as in the muscle of an animal; or 2) slower change as in differentiation of an egg or seed. Many other changes of state may relate to Ca2+ steady-state levels of flow in the circuitry and here we point to two: 1) dormancy in reptiles and animals; and 2) sporulation in both bacteria and lower plants. In the other chapters of

  5. PRECEDE for Wellness.

    ERIC Educational Resources Information Center

    Bonaguro, John A.

    1981-01-01

    The PRECEDE model was developed for health educators in an effort to improve programs and to influence health behaviors. The model consists of several diagnostic phases: (1) epidemiological; (2) social; (3) behavioral; (4) educational; (5) administrative; and (6) evaluation. (JN)

  6. Disentangling picosecond events that complicate the quantitative use of the calcium sensor YC3.60.

    PubMed

    Laptenok, S P; van Stokkum, I H M; Borst, J W; van Oort, B; Visser, A J W G; van Amerongen, H

    2012-03-01

    Yellow Cameleon 3.60 (YC3.60) is a calcium sensor based on Förster resonance energy transfer (FRET). This sensor is composed of a calmodulin domain and a M13 peptide, which are located in between enhanced cyan-fluorescent protein (ECFP) and the Venus variant of enhanced yellow-fluorescent protein (EYFP). Depending on the calcium concentration, the efficiency of FRET from donor ECFP to acceptor EYFP is changing. In this study, we have recorded time-resolved fluorescence spectra of ECFP, EYFP, and YC3.60 in aqueous solution with picosecond time resolution, using different excitation wavelengths. Detailed insight in the FRET kinetics was obtained by using global and target analyses of time- and wavelength-resolved fluorescence of purified YC3.60 in calcium-free and calcium-bound conformations. The results clearly demonstrate that for both conformations, there are two distinct donor populations: a major one giving rise to FRET and a minor one not able to perform FRET. The transfer time for the calcium-bound conformation is 21 ps, whereas it is in the order of 1 ns for the calcium-free conformation. Ratio imaging of acceptor and donor fluorescence intensities of YC3.60 is usually applied to measure Ca(2+) concentrations in living cells. From the obtained results, it is clear that the intensity ratio is strongly influenced by the presence of donor molecules that do not take part in FRET, thereby significantly affecting the quantitative interpretation of the results.

  7. Curcumin induces crosstalk between autophagy and apoptosis mediated by calcium release from the endoplasmic reticulum, lysosomal destabilization and mitochondrial events

    PubMed Central

    Moustapha, A; Pérétout, PA; Rainey, NE; Sureau, F; Geze, M; Petit, J-M; Dewailly, E; Slomianny, C; Petit, PX

    2015-01-01

    Curcumin, a major active component of turmeric (Curcuma longa, L.), has anticancer effects. In vitro studies suggest that curcumin inhibits cancer cell growth by activating apoptosis, but the mechanism underlying these effects is still unclear. Here, we investigated the mechanisms leading to apoptosis in curcumin-treated cells. Curcumin induced endoplasmic reticulum stress causing calcium release, with a destabilization of the mitochondrial compartment resulting in apoptosis. These events were also associated with lysosomal membrane permeabilization and of caspase-8 activation, mediated by cathepsins and calpains, leading to Bid cleavage. Truncated tBid disrupts mitochondrial homeostasis and enhance apoptosis. We followed the induction of autophagy, marked by the formation of autophagosomes, by staining with acridine orange in cells exposed curcumin. At this concentration, only the early events of apoptosis (initial mitochondrial destabilization with any other manifestations) were detectable. Western blotting demonstrated the conversion of LC3-I to LC3-II (light chain 3), a marker of active autophagosome formation. We also found that the production of reactive oxygen species and formation of autophagosomes following curcumin treatment was almost completely blocked by N-acetylcystein, the mitochondrial specific antioxidants MitoQ10 and SKQ1, the calcium chelators, EGTA-AM or BAPTA-AM, and the mitochondrial calcium uniporter inhibitor, ruthenium red. Curcumin-induced autophagy failed to rescue all cells and most cells underwent type II cell death following the initial autophagic processes. All together, these data imply a fail-secure mechanism regulated by autophagy in the action of curcumin, suggesting a therapeutic potential for curcumin. Offering a novel and effective strategy for the treatment of malignant cells. PMID:27551451

  8. Patterns of seismic activity preceding large earthquakes

    NASA Technical Reports Server (NTRS)

    Shaw, Bruce E.; Carlson, J. M.; Langer, J. S.

    1992-01-01

    A mechanical model of seismic faults is employed to investigate the seismic activities that occur prior to major events. The block-and-spring model dynamically generates a statistical distribution of smaller slipping events that precede large events, and the results satisfy the Gutenberg-Richter law. The scaling behavior during a loading cycle suggests small but systematic variations in space and time with maximum activity acceleration near the future epicenter. Activity patterns inferred from data on seismicity in California demonstrate a regional aspect; increased activity in certain areas are found to precede major earthquake events. One example is given regarding the Loma Prieta earthquake of 1989 which is located near a fault section associated with increased activity levels.

  9. Calcium isotopes in caves as a proxy for aridity: Modern calibration and application to the 8.2 kyr event

    NASA Astrophysics Data System (ADS)

    Owen, R. A.; Day, C. C.; Hu, C.-Y.; Liu, Y.-H.; Pointing, M. D.; Blättler, C. L.; Henderson, G. M.

    2016-06-01

    We present the first study of Ca isotope cycling in a natural cave system, with measurements of bedrock, dripwater and recently formed carbonate, coupled to a first stalagmite time-series spanning the 8.2 kyr event. Dripwaters at Heshang Cave (Central China; 30°27‧N, 110°25‧E) are isotopically heavy relative to the dolomite bedrock, the result of prior calcite precipitation (PCP) occurring earlier in the drip flow path. A simple Rayleigh fractionation model quantifies the extent of PCP in the modern environment at 36% Ca removal. The observed in situ calcium isotope fractionation factor between dripwater and carbonate is Δ 44 / 42 Ca = - 0.63 ± 0.03 ‰ and does not vary during the annual cycle. Measurements of speleothem carbonate spanning the 8.2 kyr event show the response of Ca isotopes to changing climate. δ44/42Ca increases by 0.35‰ at the onset of the event, coeval with changes in δ18O and Mg/Ca, and remains high for 80 yr. This change is explained by decreased rainfall leading to increased PCP; an interpretation supported by established PCP proxies (Mg/Ca, Sr/Ca and Ba/Ca). Ca isotopes indicate that PCP increased to 60% Ca removal during the event, which, from application of a simple box model, suggests mean annual rainfall decreased by approximately a third in Central China during the 8.2 kyr event. The response of Ca isotopes across this event demonstrates their potential for the assessment of past conditions, including past dripwater flow rates and rainfall.

  10. Calcium isotope evidence for dramatic increase of continental weathering during the Toarcian oceanic anoxic event (Early Jurassic)

    NASA Astrophysics Data System (ADS)

    Brazier, Jean-Michel; Suan, Guillaume; Tacail, Théo; Simon, Laurent; Martin, Jeremy E.; Mattioli, Emanuela; Balter, Vincent

    2015-02-01

    The early Toarcian was punctuated by pulses of massive carbon injection that are thought to have triggered, through increased greenhouse conditions, elevated continental discharge and nutrient input, marine anoxia, seawater acidification and species extinctions. Nevertheless, the mode and tempo of changes in continental weathering across this interval remains highly debated, leading to considerable uncertainty about the main causes of these perturbations. In this study we present calcium isotope measurements (δ44/40Ca) of well-preserved brachiopods and bulk rock samples from the hemipelagic strata of Pliensbachian-Toarcian age of Peniche in Portugal in order to constrain changes in the calcium cycle and hence changes in continental weathering during the early Toarcian. The data reveal a similar trend as carbon isotope data from the same section and show negative excursions of about 0.5‰ at the Pliensbachian-Toarcian transition (Pl-To) and at the base of the Toarcian Oceanic Anoxic Event (T-OAE) interval. The comparison of δ44/40Ca ratios recorded in brachiopods and bulk rock corrected for variable dolomite contribution indicates that these excursions reflect changes in the global isotopic composition of seawater rather than changes in the dominant mineralogy of calcifying organisms or in hydrological budget of the considered basin. Box modeling results suggest that the Pl-To and T-OAE δ44/40Ca excursions can be explained by a transient 90% decrease of carbonate accumulation due to seawater acidification followed by a 500% increase in continental weathering rates. The sharp increases in continental weathering inferred from the δ44/40Ca ratios seem overall consistent with lower Toarcian sedimentological and biotic records that document rapid crises in carbonate production followed by episodes of increased calcium carbonate burial. Nevertheless, the maximum of carbonate burial recorded by most NW European basinal successions occurs several hundreds of kyrs after

  11. Capsaicin mimics mechanical load-induced intracellular signaling events: involvement of TRPV1-mediated calcium signaling in induction of skeletal muscle hypertrophy.

    PubMed

    Ito, Naoki; Ruegg, Urs T; Kudo, Akira; Miyagoe-Suzuki, Yuko; Takeda, Shin'ichi

    2013-01-01

    Mechanical load-induced intracellular signaling events are important for subsequent skeletal muscle hypertrophy. We previously showed that load-induced activation of the cation channel TRPV1 caused an increase in intracellular calcium concentrations ([Ca ( 2+) ]i) and that this activated mammalian target of rapamycin (mTOR) and promoted muscle hypertrophy. However, the link between mechanical load-induced intracellular signaling events, and the TRPV1-mediated increases in [Ca ( 2+) ]i are not fully understood. Here we show that administration of the TRPV1 agonist, capsaicin, induces phosphorylation of mTOR, p70S6K, S6, Erk1/2 and p38 MAPK, but not Akt, AMPK or GSK3β. Furthermore, the TRPV1-induced phosphorylation patterns resembled those induced by mechanical load. Our results continue to highlight the importance of TRPV1-mediated calcium signaling in load-induced intracellular signaling pathways.

  12. Hybrid Markov-mass action law model for cell activation by rare binding events: Application to calcium induced vesicular release at neuronal synapses

    PubMed Central

    Guerrier, Claire; Holcman, David

    2016-01-01

    Binding of molecules, ions or proteins to small target sites is a generic step of cell activation. This process relies on rare stochastic events where a particle located in a large bulk has to find small and often hidden targets. We present here a hybrid discrete-continuum model that takes into account a stochastic regime governed by rare events and a continuous regime in the bulk. The rare discrete binding events are modeled by a Markov chain for the encounter of small targets by few Brownian particles, for which the arrival time is Poissonian. The large ensemble of particles is described by mass action laws. We use this novel model to predict the time distribution of vesicular release at neuronal synapses. Vesicular release is triggered by the binding of few calcium ions that can originate either from the synaptic bulk or from the entry through calcium channels. We report here that the distribution of release time is bimodal although it is triggered by a single fast action potential. While the first peak follows a stimulation, the second corresponds to the random arrival over much longer time of ions located in the synaptic terminal to small binding vesicular targets. To conclude, the present multiscale stochastic modeling approach allows studying cellular events based on integrating discrete molecular events over several time scales. PMID:27752087

  13. Conspecific sperm precedence in Drosophila.

    PubMed

    Price, C S

    1997-08-14

    Traits that influence the interactions between males and females can evolve very rapidly through sexual selection or sexually antagonistic coevolution. Rapid change in the fertilization systems of independent populations can give rise to reproductive incompatibilities between populations, and may contribute to speciation. Here I provide evidence for cryptic reproductive divergence among three sibling species of Drosophila that leads to a form of postmating isolation. When a female mates with both a conspecific and a heterospecific male, the conspecific sperm fertilize the vast majority of the eggs, regardless of the order of the matings. Heterospecific sperm fertilize fewer eggs after these double matings than after single matings. Experiments using spermless males show that the seminal fluid of the conspecific male is largely responsible for this conspecific sperm precedence. Moreover, when two males of the same species mate sequentially with a female from a different species, a highly variable pattern of sperm precedence replaces the second-male sperm precedence that is consistently found within species. These results indicate that females mediate sperm competition, and that second-male sperm precedence is not an automatic consequence of the mechanics of sperm storage.

  14. Upregulation of calpain activity precedes tau phosphorylation and loss of synaptic proteins in Alzheimer's disease brain.

    PubMed

    Kurbatskaya, Ksenia; Phillips, Emma C; Croft, Cara L; Dentoni, Giacomo; Hughes, Martina M; Wade, Matthew A; Al-Sarraj, Safa; Troakes, Claire; O'Neill, Michael J; Perez-Nievas, Beatriz G; Hanger, Diane P; Noble, Wendy

    2016-01-01

    Alterations in calcium homeostasis are widely reported to contribute to synaptic degeneration and neuronal loss in Alzheimer's disease. Elevated cytosolic calcium concentrations lead to activation of the calcium-sensitive cysteine protease, calpain, which has a number of substrates known to be abnormally regulated in disease. Analysis of human brain has shown that calpain activity is elevated in AD compared to controls, and that calpain-mediated proteolysis regulates the activity of important disease-associated proteins including the tau kinases cyclin-dependent kinase 5 and glycogen kinase synthase-3. Here, we sought to investigate the likely temporal association between these changes during the development of sporadic AD using Braak staged post-mortem brain. Quantification of protein amounts in these tissues showed increased activity of calpain-1 from Braak stage III onwards in comparison to controls, extending previous findings that calpain-1 is upregulated at end-stage disease, and suggesting that activation of calcium-sensitive signalling pathways are sustained from early stages of disease development. Increases in calpain-1 activity were associated with elevated activity of the endogenous calpain inhibitor, calpastatin, itself a known calpain substrate. Activation of the tau kinases, glycogen-kinase synthase-3 and cyclin-dependent kinase 5 were also found to occur in Braak stage II-III brain, and these preceded global elevations in tau phosphorylation and the loss of post-synaptic markers. In addition, we identified transient increases in total amyloid precursor protein and pre-synaptic markers in Braak stage II-III brain, that were lost by end stage Alzheimer's disease, that may be indicative of endogenous compensatory responses to the initial stages of neurodegeneration. These findings provide insight into the molecular events that underpin the progression of Alzheimer's disease, and further highlight the rationale for investigating novel treatment

  15. Upregulation of calpain activity precedes tau phosphorylation and loss of synaptic proteins in Alzheimer's disease brain.

    PubMed

    Kurbatskaya, Ksenia; Phillips, Emma C; Croft, Cara L; Dentoni, Giacomo; Hughes, Martina M; Wade, Matthew A; Al-Sarraj, Safa; Troakes, Claire; O'Neill, Michael J; Perez-Nievas, Beatriz G; Hanger, Diane P; Noble, Wendy

    2016-03-31

    Alterations in calcium homeostasis are widely reported to contribute to synaptic degeneration and neuronal loss in Alzheimer's disease. Elevated cytosolic calcium concentrations lead to activation of the calcium-sensitive cysteine protease, calpain, which has a number of substrates known to be abnormally regulated in disease. Analysis of human brain has shown that calpain activity is elevated in AD compared to controls, and that calpain-mediated proteolysis regulates the activity of important disease-associated proteins including the tau kinases cyclin-dependent kinase 5 and glycogen kinase synthase-3. Here, we sought to investigate the likely temporal association between these changes during the development of sporadic AD using Braak staged post-mortem brain. Quantification of protein amounts in these tissues showed increased activity of calpain-1 from Braak stage III onwards in comparison to controls, extending previous findings that calpain-1 is upregulated at end-stage disease, and suggesting that activation of calcium-sensitive signalling pathways are sustained from early stages of disease development. Increases in calpain-1 activity were associated with elevated activity of the endogenous calpain inhibitor, calpastatin, itself a known calpain substrate. Activation of the tau kinases, glycogen-kinase synthase-3 and cyclin-dependent kinase 5 were also found to occur in Braak stage II-III brain, and these preceded global elevations in tau phosphorylation and the loss of post-synaptic markers. In addition, we identified transient increases in total amyloid precursor protein and pre-synaptic markers in Braak stage II-III brain, that were lost by end stage Alzheimer's disease, that may be indicative of endogenous compensatory responses to the initial stages of neurodegeneration. These findings provide insight into the molecular events that underpin the progression of Alzheimer's disease, and further highlight the rationale for investigating novel treatment

  16. Calcium handling precedes cardiac differentiation to initiate the first heartbeat

    PubMed Central

    Tyser, Richard CV; Miranda, Antonio MA; Chen, Chiann-mun; Davidson, Sean M

    2016-01-01

    The mammalian heartbeat is thought to begin just prior to the linear heart tube stage of development. How the initial contractions are established and the downstream consequences of the earliest contractile function on cardiac differentiation and morphogenesis have not been described. Using high-resolution live imaging of mouse embryos, we observed randomly distributed spontaneous asynchronous Ca2+-oscillations (SACOs) in the forming cardiac crescent (stage E7.75) prior to overt beating. Nascent contraction initiated at around E8.0 and was associated with sarcomeric assembly and rapid Ca2+ transients, underpinned by sequential expression of the Na+-Ca2+ exchanger (NCX1) and L-type Ca2+ channel (LTCC). Pharmacological inhibition of NCX1 and LTCC revealed rapid development of Ca2+ handling in the early heart and an essential early role for NCX1 in establishing SACOs through to the initiation of beating. NCX1 blockade impacted on CaMKII signalling to down-regulate cardiac gene expression, leading to impaired differentiation and failed crescent maturation. DOI: http://dx.doi.org/10.7554/eLife.17113.001 PMID:27725084

  17. Mouse neuroblastoma cell based model and the effect of epileptic events on calcium oscillations and neural spikes

    NASA Astrophysics Data System (ADS)

    Kim, Suhwan; Baek, Juyeong; Jung, Unsang; Lee, Sangwon; Jung, Woonggyu; Kim, Jeehyun; Kang, Shinwon

    2013-05-01

    Recently, Mouse neuroblastoma cells are considered as an attractive model for the study of human neurological and prion diseases, and intensively used as a model system in different areas. Among those areas, differentiation of neuro2a (N2A) cells, receptor mediated ion current, and glutamate induced physiological response are actively investigated. The reason for the interest to mouse neuroblastoma N2A cells is that they have a fast growing rate than other cells in neural origin with a few another advantages. This study evaluated the calcium oscillations and neural spikes recording of mouse neuroblastoma N2A cells in an epileptic condition. Based on our observation of neural spikes in mouse N2A cell with our proposed imaging modality, we report that mouse neuroblastoma N2A cells can be an important model related to epileptic activity studies. It is concluded that the mouse neuroblastoma N2A cells produce the epileptic spikes in vitro in the same way as produced by the neurons or the astrocytes. This evidence advocates the increased and strong level of neurotransmitters release by enhancement in free calcium using the 4-aminopyridine which causes the mouse neuroblastoma N2A cells to produce the epileptic spikes and calcium oscillation.

  18. Mouse neuroblastoma cell-based model and the effect of epileptic events on calcium oscillations and neural spikes

    NASA Astrophysics Data System (ADS)

    Kim, Suhwan; Jung, Unsang; Baek, Juyoung; Lee, Sangwon; Jung, Woonggyu; Kim, Jeehyun; Kang, Shinwon

    2013-01-01

    Recently, mouse neuroblastoma cells have been considered as an attractive model for the study of human neurological and prion diseases, and they have been intensively used as a model system in different areas. For example, the differentiation of neuro2a (N2A) cells, receptor-mediated ion current, and glutamate-induced physiological responses have been actively investigated with these cells. These mouse neuroblastoma N2A cells are of interest because they grow faster than other cells of neural origin and have a number of other advantages. The calcium oscillations and neural spikes of mouse neuroblastoma N2A cells in epileptic conditions are evaluated. Based on our observations of neural spikes in these cells with our proposed imaging modality, we reported that they can be an important model in epileptic activity studies. We concluded that mouse neuroblastoma N2A cells produce epileptic spikes in vitro in the same way as those produced by neurons or astrocytes. This evidence suggests that increased levels of neurotransmitter release due to the enhancement of free calcium from 4-aminopyridine causes the mouse neuroblastoma N2A cells to produce epileptic spikes and calcium oscillations.

  19. Counselor Interventions Preceding Client Laughter in Brief Therapy.

    ERIC Educational Resources Information Center

    Falk, Dana R.; Hill, Clara E.

    1992-01-01

    Examined whether 6 categories of counselor humor and 4 categories of risk interventions preceded client laughter in 236 events from 8 cases of brief psychotherapy. Found most client laughter was mild and moderate, with only eight instances of strong laughter. Humorous interventions led to more client laughter than did interventions that encouraged…

  20. 47 CFR 213.5 - Precedence designators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Precedence designators. 213.5 Section 213.5 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.5 Precedence designators. (a) The following...

  1. Calcium supplements

    MedlinePlus

    ... TYPES OF CALCIUM SUPPLEMENTS Forms of calcium include: Calcium carbonate: Over-the-counter (OTC) antacid products, such as Tums and Rolaids, contain calcium carbonate. These sources of calcium do not cost much. ...

  2. Precedence relationship representations of mechanical assembly sequences

    NASA Technical Reports Server (NTRS)

    Homendemello, L. S.; Sanderson, A. C.

    1989-01-01

    Two types of precedence relationship representations for mechanical assembly sequences are presented: precedence relationships between the establishment of one connection between two parts and the establishment of another connection, and precedence relationships between the establishment of one connection and states of the assembly process. Precedence relationship representations have the advantage of being very compact. The problem with these representations was how to guarantee their correctness and completeness. Two theorems are presented each of which leads to the generation of one type of precedence relationship representation guaranteeing its correctness and completeness for a class of assemblies.

  3. Lesion-specific coronary artery calcium quantification for predicting cardiac event with multiple instance support vector machines.

    PubMed

    Liu, Qingshan; Qian, Zhen; Marvasty, Idean; Rinehart, Sarah; Voros, Szilard; Metaxas, Dimitris N

    2010-01-01

    Conventional whole-heart CAC quantification has been demonstrated to be insufficient in predicting coronary events, especially in accurately predicting near-term coronary events in high-risk adults. In this paper, we propose a lesion-specific CAC quantification framework to improve CAC's near-term predictive value in intermediate to high-risk populations with a novel multiple instance support vector machines (MISVM) approach. Our method works on data sets acquired with clinical imaging protocols on conventional CT scanners without modifying the CT hardware or updating the imaging protocol. The calcific lesions are quantified by geometric information, density, and some clinical measurements. A MISVM model is built to predict cardiac events, and moreover, to give a better insight of the characterization of vulnerable or culprit lesions in CAC. Experimental results on 31 patients showed significant improvement of the predictive value with the ROC analysis, the net reclassification improvement evaluation, and the leave-one-out validation against the conventional methods. PMID:20879266

  4. The effects of a whole-watershed calcium addition on the chemistry of stream storm events at the Hubbard Brook Experimental Forest in NH, USA.

    PubMed

    Cho, Youngil; Driscoll, Charles T; Blum, Joel D

    2009-10-01

    Patterns of storm runoff chemistry from a wollastonite (calcium-silicate mineral, CaSiO(3)) treated watershed (W1) were compared with a reference watershed (W6) at the Hubbard Brook Experimental Forest (HBEF) in New Hampshire (NH), USA to investigate the role of Ca(2+) supply in the acid-base status of stream chemistry. In the summer of 2003, six storm events were studied in W1 and W6 to evaluate the effects of the wollastonite treatment on the episodic acidification of stream waters. Although mean values of Ca(2+) concentrations decreased slightly from 33.8 to 31.7 mumol/L with increasing stream discharge in W1 during the events, the mean value of acid neutralizing capacity (ANC) was positive (1.2 mueq/L) during storm events, compared to negative values (-0.2 mueq/L) in W6. This pattern is presumably due to enhanced Ca(2+) supply in W1 (20.7 to 29.0% of dissolved Ca(2+) derived from the added wollastonite) to stream water as a result of interflow along shallow flowpaths. In addition, the application of wollastonite increased pH and dissolved silica (H(4)SiO(4)) concentrations, and decreased the concentration of inorganic monomeric Al (Al(i)) in W1 in comparison with W6 during storm events. Despite an increase in SO(4)(2-) concentration, likely due to desorption of sulfate from soil after the treatment, the watershed showed an increase in ANC compared to the reference watershed, serving to mitigate episodic acidification.

  5. The effects of a whole-watershed calcium addition on the chemistry of stream storm events at the Hubbard Brook Experimental Forest in NH, USA.

    PubMed

    Cho, Youngil; Driscoll, Charles T; Blum, Joel D

    2009-10-01

    Patterns of storm runoff chemistry from a wollastonite (calcium-silicate mineral, CaSiO(3)) treated watershed (W1) were compared with a reference watershed (W6) at the Hubbard Brook Experimental Forest (HBEF) in New Hampshire (NH), USA to investigate the role of Ca(2+) supply in the acid-base status of stream chemistry. In the summer of 2003, six storm events were studied in W1 and W6 to evaluate the effects of the wollastonite treatment on the episodic acidification of stream waters. Although mean values of Ca(2+) concentrations decreased slightly from 33.8 to 31.7 mumol/L with increasing stream discharge in W1 during the events, the mean value of acid neutralizing capacity (ANC) was positive (1.2 mueq/L) during storm events, compared to negative values (-0.2 mueq/L) in W6. This pattern is presumably due to enhanced Ca(2+) supply in W1 (20.7 to 29.0% of dissolved Ca(2+) derived from the added wollastonite) to stream water as a result of interflow along shallow flowpaths. In addition, the application of wollastonite increased pH and dissolved silica (H(4)SiO(4)) concentrations, and decreased the concentration of inorganic monomeric Al (Al(i)) in W1 in comparison with W6 during storm events. Despite an increase in SO(4)(2-) concentration, likely due to desorption of sulfate from soil after the treatment, the watershed showed an increase in ANC compared to the reference watershed, serving to mitigate episodic acidification. PMID:19640565

  6. 8 CFR 103.10 - Precedent decisions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... General are governed by part 1003 of 8 CFR chapter V. (b) Decisions as precedents. Except as Board... provided in paragraph (c) of this section or 8 CFR 1003.1(h)(2). (d) Publication of Secretary's precedent...; BIOMETRIC REQUIREMENTS; AVAILABILITY OF RECORDS Applying for Benefits, Surety Bonds, Fees § 103.10...

  7. 8 CFR 103.10 - Precedent decisions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... General are governed by part 1003 of 8 CFR chapter V. (b) Decisions as precedents. Except as Board... provided in paragraph (c) of this section or 8 CFR 1003.1(h)(2). (d) Publication of Secretary's precedent...; BIOMETRIC REQUIREMENTS; AVAILABILITY OF RECORDS Applying for Benefits, Surety Bonds, Fees § 103.10...

  8. 8 CFR 103.10 - Precedent decisions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... General are governed by part 1003 of 8 CFR chapter V. (b) Decisions as precedents. Except as Board... provided in paragraph (c) of this section or 8 CFR 1003.1(h)(2). (d) Publication of Secretary's precedent...; BIOMETRIC REQUIREMENTS; AVAILABILITY OF RECORDS Applying for Benefits, Surety Bonds, Fees § 103.10...

  9. Calcium Carbonate

    MedlinePlus

    Calcium carbonate is a dietary supplement used when the amount of calcium taken in the diet is not ... for healthy bones, muscles, nervous system, and heart. Calcium carbonate also is used as an antacid to relieve ...

  10. Calcium - urine

    MedlinePlus

    High levels of urine calcium (above 300 mg/day) may be due to: Chronic kidney disease High vitamin D levels Leaking of calcium from the kidneys into the urine, which causes calcium kidney stones Sarcoidosis Taking ...

  11. Oxysterols and calcium signal transduction.

    PubMed

    Mackrill, John J

    2011-09-01

    Ionised calcium (Ca(2+)) is a key second messenger, regulating almost every cellular process from cell death to muscle contraction. Cytosolic levels of this ion can be increased via gating of channel proteins located in the plasma membrane, endoplasmic reticulum and other membrane-delimited organelles. Ca(2+) can be removed from cells by extrusion across the plasma membrane, uptake into organelles and buffering by anionic components. Ca(2+) channels and extrusion mechanisms work in concert to generate diverse spatiotemporal patterns of this second messenger, the distinct profiles of which determine different cellular outcomes. Increases in cytoplasmic Ca(2+) concentration are one of the most rapid cellular responses upon exposure to certain oxysterol congeners or to oxidised low-density lipoprotein, occurring within seconds of addition and preceding increases in levels of reactive oxygen species, or changes in gene expression. Furthermore, exposure of cells to oxysterols for periods of hours to days modulates Ca(2+) signal transduction, with these longer-term alterations in cellular Ca(2+) homeostasis potentially underlying pathological events within atherosclerotic lesions, such as hyporeactivity to vasoconstrictors observed in vascular smooth muscle, or ER stress-induced cell death in macrophages. Despite their candidate roles in physiology and disease, little is known about the molecular mechanisms that couple changes in oxysterol concentrations to alterations in Ca(2+) signalling. This review examines the ways in which oxysterols could influence Ca(2+) signal transduction and the potential roles of this in health and disease. PMID:21513705

  12. More Than the Rules of Precedence

    ERIC Educational Resources Information Center

    Liang, Yawei

    2005-01-01

    In a fundamental computer-programming course, such as CSE101, questions about how to evaluate an arithmetic expression are frequently used to check if our students know the rules of precedence. The author uses two of our final examination questions to show that more knowledge of computer science is needed to answer them correctly. Furthermore,…

  13. PWORLD: A Precedent-Based Global Simulation.

    ERIC Educational Resources Information Center

    Schrodt, Philip A.

    A "world model" is constructed where precedent-searching is one of the primary driving mechanisms. The simulation assumes that nations in the system are utility maximizers but that they have relatively primitive decision mechanisms and that they are strongly influenced by their previous short-term successful behavior and the short-term success of…

  14. On the Rhetoric and Precedents of Racism.

    ERIC Educational Resources Information Center

    Villanueva, Victor

    1999-01-01

    Considers contribution of rhetorical training of the Aztecs prior to the European conquest as well as other early philosophers from the Americas. Encourages breaking precedent in order to battle racism by looking to rhetorical training developed in the Americas and Puerto Rico in addition to the European thinkers. (SC)

  15. Sleep Disturbance Preceding Completed Suicide in Adolescents

    ERIC Educational Resources Information Center

    Goldstein, Tina R.; Bridge, Jeffrey A.; Brent, David A.

    2008-01-01

    We examined sleep difficulties preceding death in a sample of adolescent suicide completers as compared with a matched sample of community control adolescents. Sleep disturbances were assessed in 140 adolescent suicide victims with a psychological autopsy protocol and in 131 controls with a similar semistructured psychiatric interview. Rates of…

  16. Thrombotic thrombocytopenic purpura preceding systemic lupus erythematosus.

    PubMed Central

    Simeon-Aznar, C P; Cuenca-Luque, R; Fonollosa-Pla, V; Bosch-Gil, J A

    1992-01-01

    The case of a patient admitted with thrombotic thrombocytopenic purpura nine years after developing systemic lupus erythematosus (SLE) is reported. Thrombotic thrombocytopenic purpura associated with SLE has been described on other occasions, but in most patients the diagnosis of SLE precedes that of thrombotic thrombocytopenic purpura. The unusual sequence and the chronological separation of the two diseases is emphasised. PMID:1575591

  17. Genome duplication and the evolution of conspecific pollen precedence

    PubMed Central

    Baldwin, Sarah J.; Husband, Brian C.

    2011-01-01

    Conspecific pollen precedence can be a strong reproductive barrier between polyploid and diploid species, but the role of genome multiplication in the evolution of this barrier has not been investigated. Here, we examine the direct effect of genome duplication on the evolution of pollen siring success in tetraploid Chamerion angustifolium. To separate the effects of genome duplication from selection after duplication, we compared pollen siring success of synthesized tetraploids (neotetraploids) with that of naturally occurring tetraploids by applying 2x, 4x (neo or established) or 2x + 4x pollen to diploid and tetraploid flowers. Seed set increased in diploids and decreased in both types of tetraploids as the proportion of pollen from diploid plants increased. Based on offspring ploidy from mixed-ploidy pollinations, pollen of the maternal ploidy always sired the majority of offspring but was strongest in established tetraploids and weakest in neotetraploids. Pollen from established tetraploids had significantly higher siring rates than neotetraploids when deposited on diploid (4xest = 47.2%, 4xneo = 27.1%) and on tetraploid recipients (4xest = 91.9%, 4xneo = 56.0%). Siring success of established tetraploids exceeded that of neotetraploids despite having similar pollen production per anther and pollen diameter. Our results suggest that, while pollen precedence can arise in association with the duplication event, the strength of polyploid siring success evolves after the duplication event. PMID:21123263

  18. Genome duplication and the evolution of conspecific pollen precedence.

    PubMed

    Baldwin, Sarah J; Husband, Brian C

    2011-07-01

    Conspecific pollen precedence can be a strong reproductive barrier between polyploid and diploid species, but the role of genome multiplication in the evolution of this barrier has not been investigated. Here, we examine the direct effect of genome duplication on the evolution of pollen siring success in tetraploid Chamerion angustifolium. To separate the effects of genome duplication from selection after duplication, we compared pollen siring success of synthesized tetraploids (neotetraploids) with that of naturally occurring tetraploids by applying 2x, 4x (neo or established) or 2x + 4x pollen to diploid and tetraploid flowers. Seed set increased in diploids and decreased in both types of tetraploids as the proportion of pollen from diploid plants increased. Based on offspring ploidy from mixed-ploidy pollinations, pollen of the maternal ploidy always sired the majority of offspring but was strongest in established tetraploids and weakest in neotetraploids. Pollen from established tetraploids had significantly higher siring rates than neotetraploids when deposited on diploid (4x(est) = 47.2%, 4x(neo) = 27.1%) and on tetraploid recipients (4x(est) = 91.9%, 4x(neo) = 56.0%). Siring success of established tetraploids exceeded that of neotetraploids despite having similar pollen production per anther and pollen diameter. Our results suggest that, while pollen precedence can arise in association with the duplication event, the strength of polyploid siring success evolves after the duplication event. PMID:21123263

  19. Threshold of the precedence effect in noise

    PubMed Central

    Freyman, Richard L.; Griffin, Amanda M.; Zurek, Patrick M.

    2014-01-01

    Three effects that show a temporal asymmetry in the influence of interaural cues were studied through the addition of masking noise: (1) The transient precedence effect—the perceptual dominance of a leading transient over a similar lagging transient; (2) the ongoing precedence effect—lead dominance with lead and lag components that extend in time; and (3) the onset capture effect—determination by an onset transient of the lateral position of an otherwise ambiguous extended trailing sound. These three effects were evoked with noise-burst stimuli and were compared in the presence of masking noise. Using a diotic noise masker, detection thresholds for stimuli with lead/lag interaural delays of 0/500 μs were compared to those with 500/0 μs delays. None of the three effects showed a masking difference between those conditions, suggesting that none of the effects is operative at masked threshold. A task requiring the discrimination between stimuli with 500/0 and 0/500 μs interaural delays was used to determine the threshold for each effect in noise. The results showed similar thresholds in noise (10–13 dB SL) for the transient and ongoing precedence effects, but a much higher threshold (33 dB SL) for onset capture of an ambiguous trailing sound. PMID:24815272

  20. An angiotensin II receptor blocker–calcium channel blocker combination prevents cardiovascular events in elderly high-risk hypertensive patients with chronic kidney disease better than high-dose angiotensin II receptor blockade alone

    PubMed Central

    Kim-Mitsuyama, Shokei; Ogawa, Hisao; Matsui, Kunihiko; Jinnouchi, Tomio; Jinnouchi, Hideaki; Arakawa, Kikuo

    2013-01-01

    The OSCAR study was a multicenter, prospective randomized open-label blinded end-point study of 1164 Japanese elderly hypertensive patients comparing the efficacy of angiotensin II receptor blocker (ARB) uptitration to an ARB plus calcium channel blocker (CCB) combination. In this prospective study, we performed prespecified subgroup analysis according to baseline estimated glomerular filtration rate (eGFR) with chronic kidney disease (CKD) defined as an eGFR <60 ml/min per 1.73 m2. Blood pressure was lower in the combined therapy than in the high-dose ARB cohort in both groups with and without CKD. In patients with CKD, significantly more primary events (a composite of cardiovascular events and noncardiovascular death) occurred in the high-dose ARB group than in the combination group (30 vs. 16, respectively, hazard ratio 2.25). Significantly more cerebrovascular and more heart failure events occurred in the high-dose ARB group than in the combination group. In patients without CKD, however, the incidence of primary events was similar between the two treatments. The treatment-by-subgroup interaction was significant. Allocation to the high-dose ARB was a significant independent prognostic factor for primary events in patients with CKD. Thus, the ARB plus CCB combination conferred greater benefit in prevention of cardiovascular events in patients with CKD compared with high-dose ARB alone. Our findings provide new insight into the antihypertensive strategy for elderly hypertensive patients with CKD. PMID:23051740

  1. Hydroclimatic conditions preceding the March 2014 Oso landslide

    USGS Publications Warehouse

    Henn, Brian; Cao, Qian; Lettenmaier, Dennis P.; Magirl, Christopher S.; Mass, Clifford; Bower, J. Brent; St. Laurent, Michael; Mao, Yixin; Perica, Sanja

    2015-01-01

    The 22 March 2014 Oso landslide was one of the deadliest in U.S. history, resulting in 43 fatalities and the destruction of more than 40 structures. We examine synoptic conditions, precipitation records and soil moisture reconstructions in the days, months, and years preceding the landslide. Atmospheric reanalysis shows a period of enhanced moisture transport to the Pacific Northwest beginning on 11 February 2014. The 21- to 42-day periods prior to the landslide had anomalously high precipitation; we estimate that 300-400 mm of precipitation fell at Oso in the 21 days prior to the landslide. Relative only to historical periods ending on 22 March, the return periods of these precipitation accumulations are large (25-88 years). However, relative to the largest accumulations from any time of the year (annual maxima), return periods are more modest (2-6 years). In addition to the 21-42 days prior to the landslide, there is a secondary maximum in the precipitation return periods for the 4 years preceding the landslide. Reconstructed soil moisture was anomalously high prior to the landslide, with a return period that exceeded 40 years about a week before the event.

  2. Continental warming preceding the Palaeocene-Eocene thermal maximum.

    PubMed

    Secord, Ross; Gingerich, Philip D; Lohmann, Kyger C; Macleod, Kenneth G

    2010-10-21

    Marine and continental records show an abrupt negative shift in carbon isotope values at ∼55.8 Myr ago. This carbon isotope excursion (CIE) is consistent with the release of a massive amount of isotopically light carbon into the atmosphere and was associated with a dramatic rise in global temperatures termed the Palaeocene-Eocene thermal maximum (PETM). Greenhouse gases released during the CIE, probably including methane, have often been considered the main cause of PETM warming. However, some evidence from the marine record suggests that warming directly preceded the CIE, raising the possibility that the CIE and PETM may have been linked to earlier warming with different origins. Yet pre-CIE warming is still uncertain. Disentangling the sequence of events before and during the CIE and PETM is important for understanding the causes of, and Earth system responses to, abrupt climate change. Here we show that continental warming of about 5 °C preceded the CIE in the Bighorn Basin, Wyoming. Our evidence, based on oxygen isotopes in mammal teeth (which reflect temperature-sensitive fractionation processes) and other proxies, reveals a marked temperature increase directly below the CIE, and again in the CIE. Pre-CIE warming is also supported by a negative amplification of δ(13)C values in soil carbonates below the CIE. Our results suggest that at least two sources of warming-the earlier of which is unlikely to have been methane-contributed to the PETM.

  3. Oral lichen planus preceding concomitant lichen planopilaris.

    PubMed

    Stoopler, Eric T; Alfaris, Sausan; Alomar, Dalal; Alawi, Faizan

    2016-09-01

    Lichen planus (LP) is an immune-mediated mucocutaneous disorder with a wide array of clinical presentations. Oral lichen planus (OLP) is characterized clinically by striae, desquamation, and/or ulceration. Lichen planopilaris (LPP), a variant of LP, affects the scalp, resulting in perifollicular erythema and scarring of cutaneous surfaces accompanied by hair loss. The association between OLP and LPP has been reported previously with scant information on concomitant or sequential disease presentation. We describe a patient with concomitant OLP and LPP, and to the best of our knowledge, this is the first report on OLP preceding the onset of LPP. PMID:27544399

  4. Measurement of calcium transients and slow calcium current in myotubes

    PubMed Central

    1994-01-01

    The purpose of this study was to characterize excitation-contraction (e- c) coupling in myotubes for comparison with e-c coupling of adult skeletal muscle. The whole cell configuration of the patch clamp technique was used in conjunction with the calcium indicator dye Fluo-3 to study the calcium transients and slow calcium currents elicited by voltage clamp pulses in cultured myotubes obtained from neonatal mice. Cells were held at -80 mV and stimulated with 15-20 ms test depolarizations preceded and followed by voltage steps designed to isolate the slow calcium current. The slow calcium current had a threshold for activation of about 0 mV; the peak amplitude of the current reached a maximum at 30 to 40 mV a and then declined for still stronger depolarizations. The calcium transient had a threshold of about -10 mV, and its amplitude increased as a sigmoidal function of test potential and did not decrease again even for test depolarizations sufficiently strong (> or = 50 mV) that the amplitude of the slow calcium current became very small. Thus, the slow calcium current in myotubes appears to have a negligible role in the process of depolarization-induced release of intracellular calcium and this process in myotubes is essentially like that in adult skeletal muscle. After repolarization, however, the decay of the calcium transient in myotubes was very slow (hundreds of ms) compared to adult muscle, particularly after strong depolarizations that triggered larger calcium transients. Moreover, when cells were repolarized after strong depolarizations, the transient typically continued to increase slowly for up to several tens of ms before the onset of decay. This continued increase after repolarization was abolished by the addition of 5 mM BAPTA to the patch pipette although the rapid depolarization-induced release was not, suggesting that the slow increase might be a regenerative response triggered by the depolarization-induced release of calcium. The addition of

  5. Heart rate dynamics preceding hemorrhage in the intensive care unit.

    PubMed

    Moss, Travis J; Clark, Matthew T; Lake, Douglas E; Moorman, J Randall; Calland, J Forrest

    2015-01-01

    Occult hemorrhage in surgical/trauma intensive care unit (STICU) patients is common and may lead to circulatory collapse. Continuous electrocardiography (ECG) monitoring may allow for early identification and treatment, and could improve outcomes. We studied 4,259 consecutive admissions to the STICU at the University of Virginia Health System. We collected ECG waveform data captured by bedside monitors and calculated linear and non-linear measures of the RR interbeat intervals. We tested the hypothesis that a transfusion requirement of 3 or more PRBC transfusions in a 24 hour period is preceded by dynamical changes in these heart rate measures and performed logistic regression modeling. We identified 308 hemorrhage events. A multivariate model including heart rate, standard deviation of the RR intervals, detrended fluctuation analysis, and local dynamics density had a C-statistic of 0.62. Earlier detection of hemorrhage might improve outcomes by allowing earlier resuscitation in STICU patients.

  6. [Wide QRS tachycardia preceded by pacemaker spikes].

    PubMed

    Romero, M; Aranda, A; Gómez, F J; Jurado, A

    2014-04-01

    The differential diagnosis and therapeutic management of wide QRS tachycardia preceded by pacemaker spike is presented. The pacemaker-mediated tachycardia, tachycardia fibrillo-flutter in patients with pacemakers, and runaway pacemakers, have a similar surface electrocardiogram, but respond to different therapeutic measures. The tachycardia response to the application of a magnet over the pacemaker could help in the differential diagnosis, and in some cases will be therapeutic, as in the case of a tachycardia-mediated pacemaker. Although these conditions are diagnosed and treated in hospitals with catheterization laboratories using the application programmer over the pacemaker, patients presenting in primary care clinic and emergency forced us to make a diagnosis and treat the haemodynamically unstable patient prior to referral. PMID:23768570

  7. Precedence effects and the evolution of chorusing

    PubMed Central

    Greenfield, M. D.; Tourtellot, M. K.; Snedden, W. A.

    1997-01-01

    The structured choruses produced by rhythmically signalling males in many species of acoustic animals have long-captured the imagination of evolutionary biologists. Though various hypotheses have been forwarded to explain the adaptive significance of such chorusing, none have withstood empirical scrutiny. We suggest instead that alternating and synchronous choruses represent collective epiphenomena resulting from individual males competing to jam each other's signals. These competitions originate in psychoacoustic precedence effects wherein females only orient toward the first call of a sequence, thus selectively favouring males who produce leading calls. Given this perceptual bias, our modelling confirms that a resetting of signal rhythm by neighbours' signals, which generates either alternation or synchrony, is evolutionarily stable provided that resetting includes a relativity adjustment for the velocity of signal transmission and selective attention toward only a subset of signalling neighbours. Signalling strategies in chorusing insects and anurans are consistent with these predicted features.

  8. Cerebral Hypoperfusion Precedes Nausea During Centrifugation

    NASA Technical Reports Server (NTRS)

    Serrador, Jorge M.; Schlegel, Todd T.; Black, F. Owen; Wood, Scott J.

    2004-01-01

    Nausea and motion sickness are important operational concerns for aviators and astronauts. Understanding underlying mechanisms associated with motion sickness may lead to new treatments. The goal of this work was to determine if cerebral blood flow changes precede the development of nausea in motion sick susceptible subjects. Cerebral flow velocity in the middle cerebral artery (transcranial Doppler), blood pressure (Finapres) and end-tidal CO2 were measured while subjects were rotated on a centrifuge (250 degrees/sec). Following 5 min of rotation, subjects were translated 0.504 m off-center, creating a +lGx centripetal acceleration in the nasal-occipital plane. Ten subjects completed the protocol without symptoms while 5 developed nausea (4 while 6ff-center and 1 while rotating on-center). Prior to nausea, subjects had significant increases in blood pressure (+13plus or minus 3 mmHg, P less than 0.05) and cerebrovascular resistance (+46 plus or minus 17%, P less than 0.05) and decreases in cerebral flow velocity both in the second (-13 plus or minus 4%) and last minute (-22 plus or minus 5%) before symptoms (P less than 0.05). In comparison, controls demonstrated no change in blood pressure or cerebrovascular resistance in the last minute of off-center rotation and only a 7 plus or minus 2% decrease in cerebral flow velocity. All subjects had significant hypocapnia (-3.8 plus or minus 0.4 mmHg, P less than 0.05), however this hypocapnia could not fully explain the cerebral hypoperfusion associated with the development of nausea. These data indicate that reductions in cerebral blood flow precede the development of nausea. Further work is necessary to determine what role cerebral hypoperfusion plays in motion sickness and whether cerebral hypoperfusion can be used to predict the development of nausea in susceptible individuals.

  9. A Solution NMR Investigation into the Early Events of Amelogenin Nanosphere Self-Assembly Initiated with Sodium Chloride or Calcium Chloride

    SciTech Connect

    Buchko, Garry W.; Tarasevich, Barbara J.; Bekhazi, Jacky G.; Snead, Malcolm L.; Shaw, Wendy J.

    2008-12-08

    Using solution-state NMR spectroscopy, new insights into the early intermolecular interactions stabilizing amelogenin supramolecular assembly and the potential role of calcium ions have been discovered. Two-dimensional 1H-15N spectra were recorded for 15N-labeled amelogenin as a function of increasing Ca2+ concentration starting from monomeric conditions. Evidence for protein-protein interactions were observed between residues E18 and E40 in the N-terminus. At higher Ca2+ concentrations there was concurrent involvement of residues in both the N- (Y12-Q56) and the C-terminus (Q144-T171). Neither specific residues nor their stepwise interaction have previously been identified in the initial stages of nanosphere assembly.

  10. Extension of the preceding birth technique.

    PubMed

    Aguirre, A

    1994-01-01

    The Brass-inspired Preceding Birth Technique (PBT), is an indirect estimation technique with low costs of administration. PBT involves asking women at a time close to delivery about the survival of the preceding births. The proportion dead is close to the probability of dying between the birth and the second birthday or an index of early childhood mortality (II or Q). Brass and Macrae have determined that II is an estimate of mortality between birth and an age lower than the birth interval or around 4/5 of the birth interval. Hospital and clinic data are likely to include a concentration of women with lower risks of disease because of higher educational levels and socioeconomic status. A simulation of PBT data from the World Fertility Survey for Mexico and Peru found that the proportions of previously dead children were 0.156 in Peru and 0.092 in Mexican home deliveries. Maternity clinic proportions were 0.088 in Peru and 0.066 in Mexico. Use of clinic and hospital data collection underestimated mortality by 32% in Peru and 15% in Mexico. Another alternative was proposed: interviewing women at some other time than delivery. If the interview was during a child/infant intervention after delivery, the subsample would still be subject to a bias, but this problem could be overcome by computing the weighted average of the actual probability of the older child being dead and the conditional probability of the younger child being dead or both younger and older children being dead. Correction factors could be applied using the general standard of the logit life table system of Brass. Calculation of a simple average of the ages of the younger children could provide enough information to help decide which tables to use. Five surveys were selected for testing the factors of dependence between probabilities of death of successive siblings: Bangladesh, Lesotho, Kenya, Ghana, and Guyana. Higher mortality was related to lower dependency factors between the probabilities of death

  11. Calcium in diet

    MedlinePlus

    ... of calcium dietary supplements include calcium citrate and calcium carbonate. Calcium citrate is the more expensive form of ... the body on a full or empty stomach. Calcium carbonate is less expensive. It is absorbed better by ...

  12. White Dwarf Convection Preceding Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Zingale, Michael; Almgren, A. S.; Bell, J. B.; Malone, C. M.; Nonaka, A.; Woosley, S. E.

    2010-01-01

    In the single degenerate scenario for Type Ia supernovae, a Chandrasekhar mass white dwarf `simmers' for centuries preceding the ultimate explosion. During this period, reactions near the center drive convection throughout most of the interior of the white dwarf. The details of this convective flow determine how the first flames in the white dwarf ignite. Simulating this phase is difficult because the flows are highly subsonic. Using the low Mach number hydrodynamics code, MAESTRO, we present 3-d, full star models of the final hours of this convective phase, up to the point of ignition of a Type Ia supernova. We discuss the details of the convective velocity field and the locations of the initial hot spots. Finally, we show some preliminary results with rotation. Support for this work came from the DOE/Office of Nuclear Physics, grant No. DE-FG02-06ER41448 (Stony Brook), the SciDAC Program of the DOE Office of Mathematics, Information, and Computational Sciences under the DOE under contract No. DE-AC02-05CH11231 (LBNL), and the DOE SciDAC program, under grant No. DE-FC02-06ER41438 (UCSC). We made use of the jaguar machine via a DOE INCITE allocation at the Oak Ridge Leadership Computational Facility.

  13. Animal Detection Precedes Access to Scene Category

    PubMed Central

    Crouzet, Sébastien M.; Joubert, Olivier R.; Thorpe, Simon J.; Fabre-Thorpe, Michèle

    2012-01-01

    The processes underlying object recognition are fundamental for the understanding of visual perception. Humans can recognize many objects rapidly even in complex scenes, a task that still presents major challenges for computer vision systems. A common experimental demonstration of this ability is the rapid animal detection protocol, where human participants earliest responses to report the presence/absence of animals in natural scenes are observed at 250–270 ms latencies. One of the hypotheses to account for such speed is that people would not actually recognize an animal per se, but rather base their decision on global scene statistics. These global statistics (also referred to as spatial envelope or gist) have been shown to be computationally easy to process and could thus be used as a proxy for coarse object recognition. Here, using a saccadic choice task, which allows us to investigate a previously inaccessible temporal window of visual processing, we showed that animal – but not vehicle – detection clearly precedes scene categorization. This asynchrony is in addition validated by a late contextual modulation of animal detection, starting simultaneously with the availability of scene category. Interestingly, the advantage for animal over scene categorization is in opposition to the results of simulations using standard computational models. Taken together, these results challenge the idea that rapid animal detection might be based on early access of global scene statistics, and rather suggests a process based on the extraction of specific local complex features that might be hardwired in the visual system. PMID:23251545

  14. Calcium Test

    MedlinePlus

    ... as thyroid disease , parathyroid disorder , malabsorption , cancer, or malnutrition An ionized calcium test may be ordered when ... albumin , which can result from liver disease or malnutrition , both of which may result from alcoholism or ...

  15. Calcium Calculator

    MedlinePlus

    ... with Sarcopenia Skeletal Rare Disorders Data & Publications Facts and Statistics Vitamin D map Fracture Risk Map Hip Fracture ... Training Courses Working Groups Regional Audits Reports Facts and Statistics Popular content Calcium content of common foods What ...

  16. The ins and outs of mitochondrial calcium.

    PubMed

    Finkel, Toren; Menazza, Sara; Holmström, Kira M; Parks, Randi J; Liu, Julia; Sun, Junhui; Liu, Jie; Pan, Xin; Murphy, Elizabeth

    2015-05-22

    Calcium is thought to play an important role in regulating mitochondrial function. Evidence suggests that an increase in mitochondrial calcium can augment ATP production by altering the activity of calcium-sensitive mitochondrial matrix enzymes. In contrast, the entry of large amounts of mitochondrial calcium in the setting of ischemia-reperfusion injury is thought to be a critical event in triggering cellular necrosis. For many decades, the details of how calcium entered the mitochondria remained a biological mystery. In the past few years, significant progress has been made in identifying the molecular components of the mitochondrial calcium uniporter complex. Here, we review how calcium enters and leaves the mitochondria, the growing insight into the topology, stoichiometry and function of the uniporter complex, and the early lessons learned from some initial mouse models that genetically perturb mitochondrial calcium homeostasis.

  17. Calcium Carbonate.

    PubMed

    Al Omari, M M H; Rashid, I S; Qinna, N A; Jaber, A M; Badwan, A A

    2016-01-01

    Calcium carbonate is a chemical compound with the formula CaCO3 formed by three main elements: carbon, oxygen, and calcium. It is a common substance found in rocks in all parts of the world (most notably as limestone), and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. CaCO3 exists in different polymorphs, each with specific stability that depends on a diversity of variables.

  18. Calcium Carbonate.

    PubMed

    Al Omari, M M H; Rashid, I S; Qinna, N A; Jaber, A M; Badwan, A A

    2016-01-01

    Calcium carbonate is a chemical compound with the formula CaCO3 formed by three main elements: carbon, oxygen, and calcium. It is a common substance found in rocks in all parts of the world (most notably as limestone), and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. CaCO3 exists in different polymorphs, each with specific stability that depends on a diversity of variables. PMID:26940168

  19. Calcium orthophosphates

    PubMed Central

    Dorozhkin, Sergey V.

    2011-01-01

    The present overview is intended to point the readers’ attention to the important subject of calcium orthophosphates. This type of materials is of special significance for human beings, because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. For example, atherosclerosis results in blood vessel blockage caused by a solid composite of cholesterol with calcium orthophosphates, while dental caries and osteoporosis mean a partial decalcification of teeth and bones, respectively, that results in replacement of a less soluble and harder biological apatite by more soluble and softer calcium hydrogenphosphates. Therefore, the processes of both normal and pathological calcifications are just an in vivo crystallization of calcium orthophosphates. Similarly, dental caries and osteoporosis might be considered an in vivo dissolution of calcium orthophosphates. Thus, calcium orthophosphates hold a great significance for humankind, and in this paper, an overview on the current knowledge on this subject is provided. PMID:23507744

  20. Height changes in the epicentral region preceding the January 17, 1994 Northridge earthquake

    USGS Publications Warehouse

    Castle, Robert O.; Packard, Robert F.; Dinitz, Laura B.

    2000-01-01

    Analysis of the results of repeated levelings through the epicentral region of the Mw 6.7, 1994 Northridge earthquake has disclosed the occurrence of differential uplift in this area that preceded the earthquake. Although the distribution of the relevant vertical-control data is somewhat sparse, in both space and time, those data that we have recovered indicate that this uplift exceeded 0.10 m and peaked 20-25 km west of the 1994 epicenter. While our data also indicate that this deformational event must have occurred during the period 1978-1989, evidence based on the character and magnitude of misclosures developed from 1987 and 1989 surveys argue that the deformation occurred largely during the period 1987-1989. The preseismic vertical-displacement field that preceded the Northridge earthquake is similar in form and, less certainly, magnitude to that which preceded the Mw 6.7, 1971 San Fernando earthquake; other possible, but less significant southern California analogues include the deformational events that preceded the Mw 5.3, 1973 Point Mugu and Mw 5.9, 1987 Whittier Narrows earthquakes. The small but growing number of recognized aseismic deformational episodes that preceded small to moderate magnitude earthquakes in southern California suggests that the deployment of the dense array of continuously recording GPS receivers planned for southern California can be expected to detect and more accurately describe such events than was heretofore possible. Moreover, if the relation between the duration of these deformational anomalies and the magnitudes of any ensuing earthquakes can be much more clearly established, the near perfect temporal control on position afforded by GPS suggests that we may be on the threshold of a realistic earthquake warning system.

  1. The evolution of conspecific sperm precedence in Drosophila.

    PubMed

    Dixon, Sheri M; Coyne, Jerry A; Noor, Mohamed A F

    2003-05-01

    Conspecific sperm precedence takes place when females inseminated by both conspecific and heterospecific sperm preferentially produce conspecific rather than hybrid offspring. Although many studies have documented conspecific sperm precedence, most have only identified it between taxa that are already considered to be good species. Here, we test for sperm precedence between two Drosophila pseudoobscura subspecies and between two Drosophila melanogaster races to evaluate how early in evolutionary divergence sperm precedence evolves. We found evidence of weak conspecific sperm precedence between the Drosophila subspecies but none between the Drosophila races. These pairs of taxa are already separated by mating discrimination and/or hybrid sterility, so our observation suggests that conspecific sperm precedence does not always evolve before other barriers to gene exchange.

  2. L-glutamine alteration of gene expression, not of polyphosphate and calcium metabolism, is a key event in arresting fungal sporulation.

    PubMed

    LéJohn, H B

    1983-05-01

    Vegetatively growing cells of the coenocytic freshwater mould Achlya developed asexual sporangia and sporulated within 6 h of postransfer to a nutrient-free (starvation) medium. Sporangial development was arrested by the addition of L-glutamine to starving cells. During starvation (minus glutamine), three polyphosphate substances accumulated intracellularly, ATP was rapidly depleted, and a protein of molecular weight 42 000 (presumed to be actin) was actively synthesized, whereas synthesis of the most abundant detergent-soluble protein of molecular weight 83 000 (p83) ceased. In the presence of glutamine, starving cells used up the polyphosphates faster than they were formed. ATP depletion was delayed, cell calcium (Ca) exited rapidly, and synthesis of actin diminished while p83 synthesis continued unabated. Several pyrimidine analogues, including 5-diazouracil (which inhibited pyridimide nucleotide biosynthesis), and inorganic phosphate prevented Ca exit from glutamine-supplemented starving cells. The pyrimidine analogues delayed but did not inhibit sporangial development; however, they did not overcome glutamine suppression of sporangial development. Vegetatively growing and starving cells displayed significantly different protein synthesis patterns (monitored by polyacrylamide gel electrophoresis) but, when glutamine was added, it changed the protein synthesis pattern of starving cells to a form typical of vegetatively growing cells. Glutamine withdrawal reversed the effect and the cells differentiated. Pyrimidine analogues and inorganic phosphate did not alter the protein synthesis patterns of starving cells in the presence and absence of glutamine. The conclusion is that glutamine inhibition of sporangial development may be linked to its ability to subvert starving cell metabolism by making it vegetative like.

  3. Short-term seismic quiescence immediately preceding explosions during the 2011 eruption of Telica Volcano, Nicaragua

    NASA Astrophysics Data System (ADS)

    Rodgers, M.; Roman, D. C.; Geirsson, H.; La Femina, P. C.; Muñoz, A.; Tenorio, V.

    2013-12-01

    Telica Volcano, Nicaragua, experienced a VEI 2 eruptive episode from March-June 2011. The eruption consisted of numerous small to moderate ash explosions, many of which were observed visually and recorded by a local broadband seismic network (the TESAND network). Seismicity at Telica during both background and eruptive periods is characterized by generally high and variable rates of low-magnitude volcano-seismic events. Explosions at Telica are also detected seismically and distinguished from volcanic earthquakes by the length of the seismic signal, their emergent nature and 'cigar-shaped' envelope, and broadband spectral content. During the month of May 2011, we identified 16 explosion events on a seismometer located 0.5 km from the crater vent, some of which correlate with visually observed explosions. From May 1-12, ten explosions are apparent in continuous seismic data. During this period, the rate of volcano-seismic events is relatively low (0-20 events/hour with an average of 4 events per hour). Prior to eight of the 10 explosions, there were no detected seismic events within one hour of the explosion. From May 13-31, seven explosions were identified in the continuous seismic data. During this period, the rate of volcano-seismic events is relatively high (0-48 events per hour, with an average of 18 events per hour). In the hour preceding all seven explosions, there were no detected volcano-seismic events. Visual inspection of the continuous seismic data confirms that a strong decrease in the number of volcano-seismic events immediately preceded most of the 2011 explosions at Telica Volcano. We suggest that the apparent short-term decrease in seismicity before explosions at Telica is related to a cycle of pressure buildup and release in the shallow magmatic-hydrothermal system, with an increase in pressure prior to the explosions both resulting from and reflecting constriction of gas pathways.

  4. 10 CFR 205.11 - Order of precedence.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Order of precedence. 205.11 Section 205.11 Energy DEPARTMENT OF ENERGY OIL ADMINISTRATIVE PROCEDURES AND SANCTIONS General Provisions § 205.11 Order of precedence. (a) If there is any conflict or inconsistency between the provisions of this part and any...

  5. 26 CFR 1.665(e)-1 - Preceding taxable year.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 8 2012-04-01 2012-04-01 false Preceding taxable year. 1.665(e)-1 Section 1.665... (CONTINUED) INCOME TAXES (CONTINUED) Treatment of Excess Distributions of Trusts Applicable to Taxable Years Beginning Before January 1, 1969 § 1.665(e)-1 Preceding taxable year. (a) Definition. For purposes...

  6. 26 CFR 1.665(e)-1 - Preceding taxable year.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 8 2011-04-01 2011-04-01 false Preceding taxable year. 1.665(e)-1 Section 1.665... (CONTINUED) INCOME TAXES (CONTINUED) Treatment of Excess Distributions of Trusts Applicable to Taxable Years Beginning Before January 1, 1969 § 1.665(e)-1 Preceding taxable year. (a) Definition. For purposes...

  7. 26 CFR 1.665(e)-1 - Preceding taxable year.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 8 2014-04-01 2014-04-01 false Preceding taxable year. 1.665(e)-1 Section 1.665... (CONTINUED) INCOME TAXES (CONTINUED) Treatment of Excess Distributions of Trusts Applicable to Taxable Years Beginning Before January 1, 1969 § 1.665(e)-1 Preceding taxable year. (a) Definition. For purposes...

  8. Control of kidney development by calcium ions.

    PubMed

    Gilbert, Thierry; Leclerc, Catherine; Moreau, Marc

    2011-12-01

    From the formation of a simple kidney in amphibian larvae, the pronephros, to the formation of the more complex mammalian kidney, the metanephros, calcium is present through numerous steps of tubulogenesis and nephron induction. Several calcium-binding proteins such as regucalcin/SMP-30 and calbindin-D28k are commonly used to label pronephric tubules and metanephric ureteral epithelium, respectively. However, the involvement of calcium and calcium signalling at various stages of renal organogenesis was not clearly delineated. In recent years, several studies have pinpointed an unsuspected role of calcium in determination of the pronephric territory and for conversion of metanephric mesenchyme into nephrons. Influx of calcium and calcium transients have been recorded in the pool of renal progenitors to allow tubule formation, highlighting the occurrence of calcium-dependent signalling events during early kidney development. Characterization of nuclear calcium signalling is emerging. Implication of the non-canonical calcium/NFAT Wnt signalling pathway as an essential mechanism to promote nephrogenesis has recently been demonstrated. This review examines the current knowledge of the impact of calcium ions during embryonic development of the kidney. It focuses on Ca(2+) binding proteins and Ca(2+) sensors that are involved in renal organogenesis and briefly examines the link between calcium-dependent signals and polycystins.

  9. Get Enough Calcium

    MedlinePlus

    ... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... 2 of 4 sections Take Action! Take Action: Calcium Sources Protect your bones – get plenty of calcium ...

  10. Calcium carbonate overdose

    MedlinePlus

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Some products that contain calcium carbonate are certain: ... and mineral supplements Other products may also contain calcium ...

  11. Calcium cyanide

    Integrated Risk Information System (IRIS)

    Jump to main content . Integrated Risk Information System Recent Additions | Contact Us Search : All EPA IRIS • You are here : EPA Home • Research • Environmental Assessment • IRIS • IRIS Summaries Redirect Page As of September 28 , 2010 , the assessment summary for calcium cyanide is included in th

  12. Characterization of superoxide overproduction by the D-LoopNox4-Nox2 cytochrome b558 in phagocytes – Differential sensitivity to calcium and phosphorylation events

    PubMed Central

    Carrichon, Laure; Picciocchi, Antoine; Debeurme, Franck; Defendi, Federica; Beaumel, Sylvain; Jesaitis, Algirdas J.; Dagher, Marie-Claire; Stasia, Marie-José

    2010-01-01

    NADPH oxidase is a crucial element of phagocytes involved in microbicidal mechanisms. It becomes active when membrane-bound cytochrome b558, the redox core, is assembled with cytosolic p47phox, p67phox, p40phox, and rac proteins to produce superoxide, the precursor for generation of toxic reactive oxygen species. In a previous study, we demonstrated that the potential second intracellular loop of Nox2 was essential to maintaining NADPH oxidase activity by controlling electron transfer from FAD to O2. Moreover, replacement of this loop by the Nox4-D-loop (D-loopNox4-Nox2) in PLB-985 cells induced superoxide overproduction. In the present investigation, we demonstrated that both soluble and particulate stimuli were able to induce this superoxide overproduction. Superoxide overproduction was also observed after phosphatidic acid activation in a purified cell-free-system assay. The highest oxidase activity was obtained after ionomycin and fMLF stimulation. In addition, enhanced sensitivity to Ca2+ influx was shown by thapsigargin, EDTA, or BTP2 treatment before fMLF activation. Mutated cytochrome b558 was less dependent on phosphorylation triggered by ERK1/2 during fMLF or PMA stimulation and by PI3K during OpZ stimulation. The superoxide overproduction of the D-loopNox4-Nox2 mutant may come from a change of responsiveness to intracellular Ca2+ level and to phosphorylation events during oxidase activation. Finally the D-loopNox4-Nox2 -PLB-985 cells were more effective against an attenuated strain of Pseudomonas aeruginosa compared to WT-Nox2 cells. The killing mechanism was biphasic, an early step of ROS production that was directly bactericidal, and a second oxidase-independent step related to the amount of ROS produced in the first step. PMID:20708598

  13. Elevation of cytosolic calcium precedes anoxic gene expression in maize suspension-cultured cells.

    PubMed Central

    Subbaiah, C C; Bush, D S; Sachs, M M

    1994-01-01

    Based on pharmacological evidence, we previously proposed that intracellular Ca2+ mediates the perception of O2 deprivation in maize seedlings. Herein, using fluorescence imaging and photometry of Ca2+ in maize suspension-cultured cells, the proposal was further investigated. Two complementary approaches were taken: (1) real time analysis of anoxia-induced changes in cytosolic Ca2+ concentration ([Ca]i) and (2) experimental manipulation of [Ca]i and then assay of the resultant anoxia-specific responses. O2 depletion caused an immediate increase in [Ca2+]i, and this was reversible within a few seconds of reoxygenation. The [Ca]i elevation proceeded independent of extracellular Ca2+. The kinetics of the Ca2+ response showed that it occurred much earlier than any detectable changes in gene expression. Ruthenium red blocked the anoxic [Ca]i elevation and also the induction of adh1 (encoding alcohol dehydrogenase) and sh1 (encoding sucrose synthase) mRNA. Ca2+, when added along with ruthenium red, prevented the effects of the antagonist on the anoxic responses. Verapamil and bepridil failed to block the [Ca]i rise induced by anoxia and were equally ineffective on anoxic gene expression. Caffeine induced an elevation of [Ca]i as well as ADH activity under normoxia. The data provide direct evidence for [Ca]i elevation in maize cells as a result of anoxia-induced mobilization of Ca2+ from intracellular stores. Furthermore, any manipulation that modified the [Ca]i rise brought about a parallel change in the expression of two anoxia-inducible genes. Thus, these results corroborate our proposal that [Ca]i is a physiological transducer of anoxia signals in plants. PMID:7866021

  14. Calcium-Dependent Signaling and Kinases in Apicomplexan Parasites

    PubMed Central

    Billker, Oliver; Lourido, Sebastian; Sibley, L. David

    2009-01-01

    Summary Calcium controls many critical events in the complex life cycles of apicomplexan parasites including protein secretion, motility, and development. Calcium levels are normally tightly regulated and rapid release of calcium into the cytosol activates a family of calcium-dependent protein kinases (CDPKs), which are normally characteristic of plants. CDPKs present in apicomplexans have acquired a number of unique domain structures likely reflecting their diverse functions. Calcium regulation in parasites is closely linked to signaling by cyclic nucleotides and their associated kinases. This review summarizes the pivotal roles that calcium-and cyclic nucleotide-dependent kinases play in unique aspects of parasite biology. PMID:19527888

  15. Calcium and Vitamin D

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium is required for the bone formation phase of bone remodeling. Typically about 5 nmol (200 mg) of calcium is removed from the adult skeleton and replaced each day. To supply this amount, one would need to consume about 600 mg of calcium, since calcium is not very efficiently absorbed. Calcium ...

  16. Coronary Calcium Scan

    MedlinePlus

    ... the NHLBI on Twitter. What Is a Coronary Calcium Scan? A coronary calcium scan is a test ... you have calcifications in your coronary arteries. Coronary Calcium Scan Figure A shows the position of the ...

  17. Calcium and bones (image)

    MedlinePlus

    Calcium is one of the most important minerals for the growth, maintenance, and reproduction of the human ... body, are continually being re-formed and incorporate calcium into their structure. Calcium is essential for the ...

  18. Calcium hydroxide poisoning

    MedlinePlus

    Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

  19. Calcium source (image)

    MedlinePlus

    Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has ... as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also effects the ...

  20. Polysomnographic findings in nights preceding a migraine attack.

    PubMed

    Göder, R; Fritzer, G; Kapsokalyvas, A; Kropp, P; Niederberger, U; Strenge, H; Gerber, W D; Aldenhoff, J B

    2001-02-01

    Sleep recordings were performed in eight patients to analyse sleep alterations preceding migraine attacks. Polysomnographic recordings from nights before an attack were compared with nights without following migraine. We analysed standard sleep parameters and electroencephalogram (EEG) power spectra. The main findings preceding migraine attacks were a significant decrease in the number of arousals, a decrease in rapid eye movement (REM) density, a significant decrease of beta power in the slow wave sleep, and a decrease of alpha power during the first REM period. The results suggest a decrease in cortical activation during sleep preceding migraine attacks. According to the models of sleep regulation, alterations in the function of aminergic or cholinergic brainstem nuclei have to be discussed. PMID:11298661

  1. Loss of calcium responsiveness in cultured bovine parathyroid cells is associated with decreased calcium receptor expression.

    PubMed

    Brown, A J; Zhong, M; Ritter, C; Brown, E M; Slatopolsky, E

    1995-07-26

    Suppression of PTH secretion by extracellular calcium is mediated by a plasma membrane calcium receptor (CaR). However, primary cultures of bovine parathyroid cells are known to quickly lose their responsiveness to extracellular calcium. The present study was designed to determine if the loss of calcium responsiveness is due to changes in CaR expression. In primary monolayer cultures of parathyroid cells, calcium-mediated suppression of PTH was still evident after 24 hours in culture but was completely absent after 6 days. This was preceded by a 75% drop in CaR mRNA content within 24 hours. CaR mRNA levels remained low for the 6-day culture. Earlier time points, examined in parathyroid cell suspensions, showed a 70% drop in CaR mRNA by 4 hours after collagenase-dispersion of the glands and an 85% drop after 24 hours. The decreased expression of CaR mRNA was not influenced by altering medium serum, calcium, or 1,25-dihydroxyvitamin D3. Our results indicate that the loss of responsiveness of cultured parathyroid cells to calcium is due to decreased CaR mRNA and, presumably, CaR protein expression.

  2. Classifying EEG Signals Preceding Right Hand, Left Hand, Tongue, and Right Foot Movements and Motor Imageries

    PubMed Central

    Morash, Valerie; Bai, Ou; Furlani, Stephen; Lin, Peter; Hallett, Mark

    2008-01-01

    Objective To use the neural signals preceding movement and motor imagery to predict which of four movements/motor imageries is about to occur, and to access this utility for brain-computer interface (BCI) applications. Methods Eight naive subjects performed or kinesthetically imagined four movements while electroencephalogram (EEG) was recorded from 29 channels over sensorimotor areas. The task was instructed with a specific stimulus (S1) and performed at a second stimulus (S2). A classifier was trained and tested offline at differentiating the EEG signals from movement/imagery preparation (the 1.5 seconds preceding movement/imagery execution). Results Accuracy of movement/imagery preparation classification varied between subjects. The system preferentially selected event related (de)synchronization (ERD/ERS) signals for classification, and high accuracies were associated with classifications that relied heavily on the ERD/ERS to discriminate movement/imagery planning. Conclusions The ERD/ERS preceding movement and motor imagery can be used to predict which of four movements/imageries is about to occur. Prediction accuracy depends on this signal’s accessibility. Significance The ERD/ERS is the most specific pre-movement/imagery signal to the movement/imagery about to be performed. PMID:18845473

  3. Preceding trauma in childhood hematogenous bone and joint infections.

    PubMed

    Pääkkönen, Markus; Kallio, Markku J T; Lankinen, Petteri; Peltola, Heikki; Kallio, Pentti E

    2014-03-01

    Preceding trauma may play a role in the etiology and pathogenesis of hematogenous bone and joint infections. Among 345 children with an acute hematogenous bone and/or joint infection, 20% reported trauma during a 2-week period leading to infection. Blunt impact, bruises, or excoriations were commonly reported. The rate was similar to that in the general pediatric population obtained from the literature. In the study group, patients with and without trauma were similar in age, serum C-reactive protein and erythrocyte sedimentation rate, length of hospitalization, and late sequelae. Preceding minor trauma did not prove to be significant as an etiological or as a prognostic factor.

  4. ATP release due to Thy-1–integrin binding induces P2X7-mediated calcium entry required for focal adhesion formation

    PubMed Central

    Henríquez, Mauricio; Herrera-Molina, Rodrigo; Valdivia, Alejandra; Alvarez, Alvaro; Kong, Milene; Muñoz, Nicolás; Eisner, Verónica; Jaimovich, Enrique; Schneider, Pascal; Quest, Andrew F. G.; Leyton, Lisette

    2011-01-01

    Thy-1, an abundant mammalian glycoprotein, interacts with αvβ3 integrin and syndecan-4 in astrocytes and thus triggers signaling events that involve RhoA and its effector p160ROCK, thereby increasing astrocyte adhesion to the extracellular matrix. The signaling cascade includes calcium-dependent activation of protein kinase Cα upstream of Rho; however, what causes the intracellular calcium transients required to promote adhesion remains unclear. Purinergic P2X7 receptors are important for astrocyte function and form large non-selective cation pores upon binding to their ligand, ATP. Thus, we evaluated whether the intracellular calcium required for Thy-1-induced cell adhesion stems from influx mediated by ATP-activated P2X7 receptors. Results show that adhesion induced by the fusion protein Thy-1-Fc was preceded by both ATP release and sustained intracellular calcium elevation. Elimination of extracellular ATP with Apyrase, chelation of extracellular calcium with EGTA, or inhibition of P2X7 with oxidized ATP, all individually blocked intracellular calcium increase and Thy-1-stimulated adhesion. Moreover, Thy-1 mutated in the integrin-binding site did not trigger ATP release, and silencing of P2X7 with specific siRNA blocked Thy-1-induced adhesion. This study is the first to demonstrate a functional link between αvβ3 integrin and P2X7 receptors, and to reveal an important, hitherto unanticipated, role for P2X7 in calcium-dependent signaling required for Thy-1-stimulated astrocyte adhesion. PMID:21502139

  5. Calcium quarks.

    PubMed

    Niggli, Ernst; Egger, Marcel

    2002-05-01

    Elementary subcellular Ca2+ signals arising from the opening of single ion channels may offer the possibility to examine the stochastic behavior and the microscopic chemical reaction rates of these channel proteins in their natural environment. Such an analysis can yield detailed information about the molecular function that cannot be derived from recordings obtained from an ensemble of channels. In this review, we summarize experimental evidence suggesting that Ca2+ sparks, elementary Ca2+ signaling events of cardiac and skeletal muscle excitation contraction coupling, may be comprised of a number of smaller Ca2+ signaling events, the Ca2+ quarks.

  6. Clinical events in high-risk hypertensive patients randomly assigned to calcium channel blocker versus angiotensin-converting enzyme inhibitor in the antihypertensive and lipid-lowering treatment to prevent heart attack trial.

    PubMed

    Leenen, Frans H H; Nwachuku, Chuke E; Black, Henry R; Cushman, William C; Davis, Barry R; Simpson, Lara M; Alderman, Michael H; Atlas, Steven A; Basile, Jan N; Cuyjet, Aloysius B; Dart, Richard; Felicetta, James V; Grimm, Richard H; Haywood, L Julian; Jafri, Syed Z A; Proschan, Michael A; Thadani, Udho; Whelton, Paul K; Wright, Jackson T

    2006-09-01

    The Antihypertensive and Lipid-Lowering treatment to prevent Heart Attack Trial (ALLHAT) provides a unique opportunity to compare the long-term relative safety and efficacy of angiotensin-converting enzyme inhibitor and calcium channel blocker-initiated therapy in older hypertensive individuals. Patients were randomized to amlodipine (n=9048) or lisinopril (n=9054). The primary outcome was combined fatal coronary heart disease or nonfatal myocardial infarction, analyzed by intention-to-treat. Secondary outcomes included all-cause mortality, stroke, combined cardiovascular disease (CVD), end-stage renal disease (ESRD), cancer, and gastrointestinal bleeding. Mean follow-up was 4.9 years. Blood pressure control was similar in nonblacks, but not in blacks. No significant differences were found between treatment groups for the primary outcome, all-cause mortality, ESRD, or cancer. Stroke rates were higher on lisinopril in blacks (RR=1.51, 95% CI 1.22 to 1.86) but not in nonblacks (RR=1.07, 95% CI 0.89 to 1.28), and in women (RR=1.45, 95% CI 1.17 to 1.79), but not in men (RR=1.10, 95% CI 0.92 to 1.31). Rates of combined CVD were higher (RR=1.06, 95% CI 1.00 to 1.12) because of higher rates for strokes, peripheral arterial disease, and angina, which were partly offset by lower rates for heart failure (RR=0.87, 95% CI 0.78 to 0.96) on lisinopril compared with amlodipine. Gastrointestinal bleeds and angioedema were higher on lisinopril. Patients with and without baseline coronary heart disease showed similar outcome patterns. We conclude that in hypertensive patients, the risks for coronary events are similar, but for stroke, combined CVD, gastrointestinal bleeding, and angioedema are higher and for heart failure are lower for lisinopril-based compared with amlodipine-based therapy. Some, but not all, of these differences may be explained by less effective blood pressure control in the lisinopril arm.

  7. The Role of Sexual Precedence in Verbal Sexual Coercion

    ERIC Educational Resources Information Center

    Livingston, Jennifer A.; Buddie, Amy M.; Testa, Maria; VanZile-Tamsen, Carol

    2004-01-01

    Experiences of verbal sexual coercion are common and have potential for negative consequences, yet are not well understood. This study used qualitative and descriptive statistics to examine verbal sexual coercion experiences among a community sample of 114 women and explored the role of sexual precedence in these experiences. Analyses revealed…

  8. Metrical expectations from preceding prosody influence perception of lexical stress.

    PubMed

    Brown, Meredith; Salverda, Anne Pier; Dilley, Laura C; Tanenhaus, Michael K

    2015-04-01

    Two visual-world experiments tested the hypothesis that expectations based on preceding prosody influence the perception of suprasegmental cues to lexical stress. The results demonstrate that listeners' consideration of competing alternatives with different stress patterns (e.g., 'jury/gi'raffe) can be influenced by the fundamental frequency and syllable timing patterns across material preceding a target word. When preceding stressed syllables distal to the target word shared pitch and timing characteristics with the first syllable of the target word, pictures of alternatives with primary lexical stress on the first syllable (e.g., jury) initially attracted more looks than alternatives with unstressed initial syllables (e.g., giraffe). This effect was modulated when preceding unstressed syllables had pitch and timing characteristics similar to the initial syllable of the target word, with more looks to alternatives with unstressed initial syllables (e.g., giraffe) than to those with stressed initial syllables (e.g., jury). These findings suggest that expectations about the acoustic realization of upcoming speech include information about metrical organization and lexical stress and that these expectations constrain the initial interpretation of suprasegmental stress cues. These distal prosody effects implicate online probabilistic inferences about the sources of acoustic-phonetic variation during spoken-word recognition.

  9. Impact of preceding crop on alfalfa competitiveness with weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic producers would like to include no-till practices in their farming systems. We are seeking to develop a continuous no-till system for organic farming, based on a complex rotation that includes a 3-year sequence of alfalfa. In this study, we evaluated impact of preceding crop on weed infest...

  10. 48 CFR 3452.215-33 - Order of precedence.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Order of precedence. 3452.215-33 Section 3452.215-33 Federal Acquisition Regulations System DEPARTMENT OF EDUCATION ACQUISITION REGULATION CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and...

  11. Henoch-Schönlein purpura with preceding abdominal pain.

    PubMed

    Toshihiko, Kakiuchi; Tomonobu, Aoki

    2015-06-01

    Diagnosing HSP can be difficult, especially when abdominal symptoms precede the onset of characteristic palpable purpura (Chen MJ et al. 2005, World Gastroenterol., 11, 2354). Therefore, it is necessary to consider the possibility of HSP in patients with prolonged strong abdominal pain, even in cases without purpura.

  12. Henoch–Schönlein purpura with preceding abdominal pain

    PubMed Central

    Toshihiko, Kakiuchi; Tomonobu, Aoki

    2015-01-01

    Key Clinical Message Diagnosing HSP can be difficult, especially when abdominal symptoms precede the onset of characteristic palpable purpura (Chen MJ et al. 2005, World Gastroenterol., 11, 2354). Therefore, it is necessary to consider the possibility of HSP in patients with prolonged strong abdominal pain, even in cases without purpura. PMID:26185663

  13. Metrical expectations from preceding prosody influence perception of lexical stress.

    PubMed

    Brown, Meredith; Salverda, Anne Pier; Dilley, Laura C; Tanenhaus, Michael K

    2015-04-01

    Two visual-world experiments tested the hypothesis that expectations based on preceding prosody influence the perception of suprasegmental cues to lexical stress. The results demonstrate that listeners' consideration of competing alternatives with different stress patterns (e.g., 'jury/gi'raffe) can be influenced by the fundamental frequency and syllable timing patterns across material preceding a target word. When preceding stressed syllables distal to the target word shared pitch and timing characteristics with the first syllable of the target word, pictures of alternatives with primary lexical stress on the first syllable (e.g., jury) initially attracted more looks than alternatives with unstressed initial syllables (e.g., giraffe). This effect was modulated when preceding unstressed syllables had pitch and timing characteristics similar to the initial syllable of the target word, with more looks to alternatives with unstressed initial syllables (e.g., giraffe) than to those with stressed initial syllables (e.g., jury). These findings suggest that expectations about the acoustic realization of upcoming speech include information about metrical organization and lexical stress and that these expectations constrain the initial interpretation of suprasegmental stress cues. These distal prosody effects implicate online probabilistic inferences about the sources of acoustic-phonetic variation during spoken-word recognition. PMID:25621583

  14. Henoch-Schönlein purpura with preceding abdominal pain.

    PubMed

    Toshihiko, Kakiuchi; Tomonobu, Aoki

    2015-06-01

    Diagnosing HSP can be difficult, especially when abdominal symptoms precede the onset of characteristic palpable purpura (Chen MJ et al. 2005, World Gastroenterol., 11, 2354). Therefore, it is necessary to consider the possibility of HSP in patients with prolonged strong abdominal pain, even in cases without purpura. PMID:26185663

  15. Metrical expectations from preceding prosody influence perception of lexical stress

    PubMed Central

    Brown, Meredith; Salverda, Anne Pier; Dilley, Laura C.; Tanenhaus, Michael K.

    2015-01-01

    Two visual-world experiments tested the hypothesis that expectations based on preceding prosody influence the perception of suprasegmental cues to lexical stress. The results demonstrate that listeners’ consideration of competing alternatives with different stress patterns (e.g., ‘jury/gi’raffe) can be influenced by the fundamental frequency and syllable timing patterns across material preceding a target word. When preceding stressed syllables distal to the target word shared pitch and timing characteristics with the first syllable of the target word, pictures of alternatives with primary lexical stress on the first syllable (e.g., jury) initially attracted more looks than alternatives with unstressed initial syllables (e.g., giraffe). This effect was modulated when preceding unstressed syllables had pitch and timing characteristics similar to the initial syllable of the target word, with more looks to alternatives with unstressed initial syllables (e.g., giraffe) than to those with stressed initial syllables (e.g., jury). These findings suggest that expectations about the acoustic realization of upcoming speech include information about metrical organization and lexical stress, and that these expectations constrain the initial interpretation of suprasegmental stress cues. These distal prosody effects implicate on-line probabilistic inferences about the sources of acoustic-phonetic variation during spoken-word recognition. PMID:25621583

  16. CALCIUM-RICH GAP TRANSIENTS: SOLVING THE CALCIUM CONUNDRUM IN THE INTRACLUSTER MEDIUM

    SciTech Connect

    Mulchaey, John S.; Kollmeier, Juna A.; Kasliwal, Mansi M.

    2014-01-10

    X-ray measurements suggest that the abundance of calcium in the intracluster medium is higher than can be explained using favored models for core-collapse and Type Ia supernovae alone. We investigate whether the ''calcium conundrum'' in the intracluster medium can be alleviated by including a contribution from the recently discovered subclass of supernovae known as calcium-rich gap transients. Although the calcium-rich gap transients make up only a small fraction of all supernovae events, we find that their high calcium yields are sufficient to reproduce the X-ray measurements found for nearby rich clusters. We find the χ{sup 2} goodness-of-fit metric improves from 84 to 2 by including this new class. Moreover, calcium-rich supernovae preferentially occur in the outskirts of galaxies making it easier for the nucleosynthesis products of these events to be incorporated in the intracluster medium via ram-pressure stripping. The discovery of calcium-rich gap transients in clusters and groups far from any individual galaxy suggests that supernovae associated with intracluster stars may play an important role in enriching the intracluster medium. Calcium-rich gap transients may also help explain anomalous calcium abundances in many other astrophysical systems including individual stars in the Milky Way, the halos of nearby galaxies, and the circumgalactic medium. Our work highlights the importance of considering the diversity of supernovae types and corresponding yields when modeling the abundance of the intracluster medium and other gas reservoirs.

  17. Update on coronary artery calcium imaging.

    PubMed

    Hergott, Lawrence J

    2005-01-01

    This update of coronary calcium imaging discusses methods of detecting and measuring coronary artery calcium and their correlation to coronary artery disease risk. The value of EBCT to traditional non-invasive cardiovascular tests is compared. A negative EBCT test makes the presence of atherosclerotic plaque, including unstable plaque, very unlikely. Negative EBCT may be consistent with low risk of a cardiovascular event over the next 2-5 years. Conversely, positive EBCT confirms the presence of a coronary plaque. The greater the amount of calcium, the greater the likelihood of occlusive disease, but there is a not a 1:1 relationship and findings may not be site specific. A high calcium score may be consistent with moderate to high risk of cardiovascular event within the next 2-5 years. Limitations and cautions concerning the general use of EBCT for screening are discussed. PMID:16060542

  18. [Calcium kidney stones. Diagnostic and preventive prospects].

    PubMed

    Arcidiacono, T; Terranegra, A; Biasion, R; Soldati, L; Vezzoli, G

    2007-01-01

    Kidney stone disease is one of the main causes of hospitalization in Italy. Its prevalence increased in the last century and is probably still increasing. The pathogenesis of the disease is not known, although two main theories have been elaborated. The first hypothesizes that hydroxyapatite deposition in the interstitium of the renal papillae (Randall's plaque) precedes urinary calcium oxalate precipitation on the ulcered surface of the papilla to form a stone. The second presumes the tubular lumen of Bellini's duct to be the site where calcium-oxalate salts precipitate to form the nucleus for stone formation within the urinary tract. These pathogenetic processes may be favored by different dietary and genetic factors. The genes involved are not known, although many studies have been performed. Polymorphisms of genes coding for the vitamin D receptor, calcium-sensing receptor, interleukin-1 receptor antagonist, and urokinase were found to be associated with kidney stones, but these results have not been replicated. Different nutrients are suspected to predispose patients to calcium kidney stone disease. A high intake of animal proteins, sodium, vitamin C and oxalate has been implicated in stone formation, whereas calcium, alkalis and phytate may have a protective effect. The prevention of calcium stone formation is based on the recognition of risk factors like those already mentioned here. Furthermore, a family history of kidney stones may be useful in identifying subjects predisposed to become calcium stone formers. However, the expectations of the scientific community are turned to the advances in genetics and to the findings of genetic studies, which may provide diagnostic tools and criteria to define the risk profile of the single individual.

  19. Extended precedence preservative crossover for job shop scheduling problems

    NASA Astrophysics Data System (ADS)

    Ong, Chung Sin; Moin, Noor Hasnah; Omar, Mohd

    2013-04-01

    Job shop scheduling problems (JSSP) is one of difficult combinatorial scheduling problems. A wide range of genetic algorithms based on the two parents crossover have been applied to solve the problem but multi parents (more than two parents) crossover in solving the JSSP is still lacking. This paper proposes the extended precedence preservative crossover (EPPX) which uses multi parents for recombination in the genetic algorithms. EPPX is a variation of the precedence preservative crossover (PPX) which is one of the crossovers that perform well to find the solutions for the JSSP. EPPX is based on a vector to determine the gene selected in recombination for the next generation. Legalization of children (offspring) can be eliminated due to the JSSP representation encoded by using permutation with repetition that guarantees the feasibility of chromosomes. The simulations are performed on a set of benchmarks from the literatures and the results are compared to ensure the sustainability of multi parents recombination in solving the JSSP.

  20. Foreshock Patterns Preceding Great Earthquakes in the Subduction Zone of Chile

    NASA Astrophysics Data System (ADS)

    Papadopoulos, G. A.; Minadakis, G.

    2016-07-01

    Foreshock activity is considered as one of the most promising precursory changes for the main shock prediction in the short term. Averaging over several foreshock sequences has shown that foreshocks are characterized by distinct 3D patterns: their epicenters move towards the main shock epicenter, event count accelerates, and b-value drops. However, these space-time-size patterns were verified so far only in a very few individual cases mainly due to inadequate seismicity catalogue data. We have investigated 3D foreshock patterns before the M w 8.8 Maule in 27 February 2010, M w 8.1 Iquique in 1 April 2014, and M w 8.4 Illapel in 16 September 2015 great earthquakes in the Chile subduction zone. To avoid biased results, no a priori spatiotemporal definitions of foreshocks were inserted. The procedure was based on pattern recognition from statistically significant seismicity changes in the three domains. The pattern recognition in one domain was independent of the pattern recognition in another domain. We found and verified with two independent catalogue data sets (CSN, IPOC) that within a critical area of ca. 65 km from the main shock epicenter, the 2014 event was preceded by distinct foreshock 3D patterns. A nearly weak foreshock stage (20 January-14 March 2014) was followed by a main-strong stage (15 March-1 April 2014) highly significant in all domains, although foreshock activity slightly decreased in about the last 5 days. Seismic moment release also accelerated in the last stage due to the occurrence of a cluster of very strong foreshock events. Foreshock activity very likely occurred in the hanging-wall fault domain on the South American Plate overriding Nazca Plate. The 2014 foreshock activity was quite similar to the one preceding the 6 Apr. 2009 L' Aquila (Italy) M w 6.3 earthquake associated with normal faulting. Using the 2014 earthquake as a reference event, we observed that similar foreshock 3D patterns preceded the 2010 and 2015 earthquakes within

  1. Foreshock Patterns Preceding Great Earthquakes in the Subduction Zone of Chile

    NASA Astrophysics Data System (ADS)

    Papadopoulos, G. A.; Minadakis, G.

    2016-10-01

    Foreshock activity is considered as one of the most promising precursory changes for the main shock prediction in the short term. Averaging over several foreshock sequences has shown that foreshocks are characterized by distinct 3D patterns: their epicenters move towards the main shock epicenter, event count accelerates, and b-value drops. However, these space-time-size patterns were verified so far only in a very few individual cases mainly due to inadequate seismicity catalogue data. We have investigated 3D foreshock patterns before the M w 8.8 Maule in 27 February 2010, M w 8.1 Iquique in 1 April 2014, and M w 8.4 Illapel in 16 September 2015 great earthquakes in the Chile subduction zone. To avoid biased results, no a priori spatiotemporal definitions of foreshocks were inserted. The procedure was based on pattern recognition from statistically significant seismicity changes in the three domains. The pattern recognition in one domain was independent of the pattern recognition in another domain. We found and verified with two independent catalogue data sets (CSN, IPOC) that within a critical area of ca. 65 km from the main shock epicenter, the 2014 event was preceded by distinct foreshock 3D patterns. A nearly weak foreshock stage (20 January-14 March 2014) was followed by a main-strong stage (15 March-1 April 2014) highly significant in all domains, although foreshock activity slightly decreased in about the last 5 days. Seismic moment release also accelerated in the last stage due to the occurrence of a cluster of very strong foreshock events. Foreshock activity very likely occurred in the hanging-wall fault domain on the South American Plate overriding Nazca Plate. The 2014 foreshock activity was quite similar to the one preceding the 6 Apr. 2009 L' Aquila (Italy) M w 6.3 earthquake associated with normal faulting. Using the 2014 earthquake as a reference event, we observed that similar foreshock 3D patterns preceded the 2010 and 2015 earthquakes within

  2. Planning school based sexuality programs utilizing the PRECEDE model.

    PubMed

    Rubinson, L; Baillie, L

    1981-04-01

    Both substantive and methodological issues in teenage sexuality were explored. Specific study purposes were the following: 1) to explore the effectiveness of a community needs assessment to reduce traditional negative parental input and facilitating the use of the schools as public health resources; 2) to identify substantive targets of intervention for curriculum development which would be accepted and supported by both parents and teenagers; and 3) to develop a methodology of assessment where the PRECEDE model would be tested for its utility in identifying educational targets in a complex and multidimensional area such as human sexuality and to quantify the model's categories to identify major differences in perceptions between parents and teenagers, and to explore underlying constructs in teenage sexuality. The PRECEDE model provides an assessment of social and epidemiological factors as well as an investigation of the behavioral causes of the outcomes as identified by the community. 50% of the population of 600 families living in a small midwestern community were surveyed: 204 parents and 210 teenagers responded to the survey. The following were among the major findings: 1) a community needs assessment using the PRECEDE model was effective in reducing negative political input and in facilitating the use of the schools as public health resources; 2) there were major needs, especially in the identification of important social problems; and 3) 24% of the teenagers reported they were sexually active while only 10% of the parents perceived their children as being sexually active.

  3. CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, CALCIUM CHLORIDE STORAGE BUILDING ON RIGHT WITH SA (SODA ASH) BUILDING IN RIGHT BACKGROUND. - Solvay Process Company, Calcium Chloride Plant, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

  4. Calcium and Vitamin D

    MedlinePlus

    ... to your weekly shopping list. Produce Serving Size Estimated Calcium* Collard greens, frozen 8 oz 360 mg ... Oranges 1 whole 55 mg Seafood Serving Size Estimated Calcium* Sardines, canned with bones 3 oz 325 ...

  5. Fenoprofen calcium overdose

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002649.htm Fenoprofen calcium overdose To use the sharing features on this page, please enable JavaScript. Fenoprofen calcium is a type of medicine called a nonsteroidal ...

  6. Calcium and bones

    MedlinePlus

    ... only gets the calcium it needs through the food you eat, or from supplements. If you do ... materials it needs to build bones. High-calcium foods include: Milk Cheese Ice cream Leafy green vegetables, ...

  7. Foreshock patterns preceding large earthquakes in the subduction zone of Chile

    NASA Astrophysics Data System (ADS)

    Minadakis, George; Papadopoulos, Gerassimos A.

    2016-04-01

    Some of the largest earthquakes in the globe occur in the subduction zone of Chile. Therefore, it is of particular interest to investigate foreshock patterns preceding such earthquakes. Foreshocks in Chile were recognized as early as 1960. In fact, the giant (Mw9.5) earthquake of 22 May 1960, which was the largest ever instrumentally recorded, was preceded by 45 foreshocks in a time period of 33h before the mainshock, while 250 aftershocks were recorded in a 33h time period after the mainshock. Four foreshocks were bigger than magnitude 7.0, including a magnitude 7.9 on May 21 that caused severe damage in the Concepcion area. More recently, Brodsky and Lay (2014) and Bedford et al. (2015) reported on foreshock activity before the 1 April 2014 large earthquake (Mw8.2). However, 3-D foreshock patterns in space, time and size were not studied in depth so far. Since such studies require for good seismic catalogues to be available, we have investigated 3-D foreshock patterns only before the recent, very large mainshocks occurring on 27 February 2010 (Mw 8.8), 1 April 2014 (Mw8.2) and 16 September 2015 (Mw8.4). Although our analysis does not depend on a priori definition of short-term foreshocks, our interest focuses in the short-term time frame, that is in the last 5-6 months before the mainshock. The analysis of the 2014 event showed an excellent foreshock sequence consisting by an early-weak foreshock stage lasting for about 1.8 months and by a main-strong precursory foreshock stage that was evolved in the last 18 days before the mainshock. During the strong foreshock period the seismicity concentrated around the mainshock epicenter in a critical area of about 65 km mainly along the trench domain to the south of the mainshock epicenter. At the same time, the activity rate increased dramatically, the b-value dropped and the mean magnitude increased significantly, while the level of seismic energy released also increased. In view of these highly significant seismicity

  8. Strontium Substitution for Calcium in Lithogenesis

    PubMed Central

    Blaschko, Sarah D.; Chi, Thomas; Miller, Joe; Flechner, Lawrence; Fakra, Sirine; Kapahi, Pankaj; Kahn, Arnold; Stoller, Marshall L.

    2013-01-01

    Purpose Strontium has chemical similarity to calcium, which enables the replacement of calcium by strontium in biomineralization processes. Incorporating strontium into human bone and teeth has been studied extensively but little research has been performed of the incorporation of strontium into urinary calculi. We used synchrotron based x-ray fluorescence and x-ray absorption techniques to examine the presence of strontium in different types of human kidney stones. Materials and Methods Multiple unique human stone samples were obtained via consecutive percutaneous nephrolithotomies/ureteroscopies. A portion of each stone was sent for standard laboratory analysis and a portion was retained for x-ray fluorescence and x-ray absorption measurements. X-ray fluorescence and x-ray absorption measurements determined the presence, spatial distribution and speciation of strontium in each stone sample. Results Traditional kidney stone analyses identified calcium oxalate, calcium phosphate, uric acid and cystine stones. X-ray fluorescence measurements identified strontium in all stone types except pure cystine. X-ray fluorescence elemental mapping of the samples revealed co-localization of calcium and strontium. X-ray absorption measurements of the calcium phosphate stone showed strontium predominately present as strontium apatite. Conclusions Advanced x-ray fluorescence imaging identified strontium in all calcium based stones, present as strontium apatite. This finding may be critical since apatite is thought to be the initial nidus for calcium stone formation. Strontium is not identified by standard laboratory stone analyses. Its substitution for calcium can be reliably identified in stones from multiple calcium based stone formers, which may offer opportunities to gain insight into early events in lithogenesis. PMID:23260568

  9. Calcium and Mitosis

    NASA Technical Reports Server (NTRS)

    Hepler, P.

    1983-01-01

    Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.

  10. APOE polymorphisms influence longitudinal lipid trends preceding intracerebral hemorrhage

    PubMed Central

    Phuah, Chia-Ling; Raffeld, Miriam R.; Ayres, Alison M.; Gurol, M. Edip; Viswanathan, Anand; Greenberg, Steven M.; Biffi, Alessandro; Rosand, Jonathan

    2016-01-01

    Objective: We sought to determine whether APOE genotype influences a previously observed decline in serum total cholesterol (TC) and low-density lipoprotein (LDL) levels preceding primary intracerebral hemorrhage (ICH), as a potential demonstration of nonamyloid mechanisms of APOE in ICH risk. Methods: We performed a single-center retrospective longitudinal analysis using patients with known APOE genotype drawn from an ongoing cohort study of ICH. Serum lipid measurements for TC, triglycerides (TGs), LDL, and high-density lipoprotein (HDL) collected within 2 years before and after index ICH were extracted from electronic medical records. Piecewise linear mixed-effects models were used to compare APOE allele–specific effects on temporal serum lipid trends in ICH. Demographics, medical history, medications, and health maintenance data were included as fixed effects. Inter- and intraindividual variations in lipid levels were modeled as random effects. Results: A total of 124 ICH cases were analyzed. APOE ε4 carriers had greater rates of decline in serum TC and LDL within 6 months preceding ICH (TC: −7.30 mg/dL/mo, p = 0.0035; LDL: −8.44 mg/dL/mo, p = 0.0001). Conversely, serum TC and LDL levels in APOE ε2 carriers were unchanged within the same time period. APOE genotype had no associations with serum HDL or TG trends. Conclusions: APOE allele status predicts serum TC and LDL changes preceding acute ICH. Our results have implications for ongoing efforts in dissecting the role of dyslipidemia in cerebrovascular disease risk. APOE genotype–specific influence on lipid trends provides a clue for one mechanism by which APOE may influence risk of ICH. Further characterization of the metabolic roles of APOE is needed to improve the understanding of APOE biology in cerebrovascular disease risk. PMID:27433544

  11. Low voltage electrical activity preceding right atrial depolarisation in man.

    PubMed Central

    Mackintosh, A F; English, M J; Vincent, R; Woollons, D J; Chamberlain, D A

    1979-01-01

    Electrical recordings were made in the high right atrium in 28 patients undergoing cardiac catheterisation and in 3 healthy volunteers. After filtering and amplification by 3 to 10 million times, the signals were passed through a signal averaging process in a digital computer. Of the 28 subjects who had technically satisfactory recordings, 23 showed low voltage electrical activity preceding the conventionally-recorded atrial depolarisation. The low voltage activity started 50 to 200 ms before the atrial deflection and was variable in shape. These early signals may be the result of activity in the region of the sinus node. PMID:486271

  12. Learning-induced modulations of the stimulus-preceding negativity.

    PubMed

    Morís, Joaquín; Luque, David; Rodríguez-Fornells, Antoni

    2013-09-01

    The neural basis of feedback expectation, which is crucial in learning theory, has only been minimally studied. Stimulus-preceding negativity (SPN), an ERP component that appears prior to the presentation of feedback, has been proposed as being related to feedback expectation. The present study showed, for the first time, amplitude modulations of the SPN component during learning acquisition in a trial-by-trial associative learning task. The results indicate that SPN could be a plausible electrophysiological index of the cognitive processes engaged while expecting the appearance of relevant feedback during reinforcement learning.

  13. Vitiligo disease triggers: psychological stressors preceding the onset of disease.

    PubMed

    Silverberg, Jonathan I; Silverberg, Nanette B

    2015-05-01

    Vitiligo is the loss of skin pigmentation caused by autoimmune destruction of melanocytes. Little is known about the impact of psychological stressors preceding vitiligo onset on symptoms associated with vitiligo and the extent of disease. We performed a questionnaire-based study of 1541 adults with vitiligo to evaluate the impact of psychological stressors in this patient population. Psychological stressors should be considered as potential disease triggers in vitiligo patients, and screening of vitiligo patients for psychological stressors and associated symptoms should be included in routine assessment.

  14. Precedence based speech segregation in bilateral cochlear implant users

    PubMed Central

    Hossain, Shaikat; Montazeri, Vahid; Assmann, Peter F.; Litovsky, Ruth Y.

    2015-01-01

    The precedence effect (PE) enables the perceptual dominance by a source (lead) over an echo (lag) in reverberant environments. In addition to facilitating sound localization, the PE can play an important role in spatial unmasking of speech. Listeners attending to binaural vocoder simulations with identical channel center frequencies and phase demonstrated PE-based benefits in a closed-set speech segregation task. When presented with the same stimuli, bilateral cochlear implant users did not derive such benefits. These findings suggest that envelope extraction in itself may not lead to a breakdown of the PE benefits, and that other factors may play a role. PMID:26723365

  15. Calcium supplements: benefits and risks.

    PubMed

    Reid, I R; Bristow, S M; Bolland, M J

    2015-10-01

    Calcium is an essential element in the diet, but there is continuing controversy regarding its optimal intake, and its role in the pathogenesis of osteoporosis. Most studies show little evidence of a relationship between calcium intake and bone density, or the rate of bone loss. Re-analysis of data from the placebo group from the Auckland Calcium Study demonstrates no relationship between dietary calcium intake and rate of bone loss over 5 years in healthy older women with intakes varying from <400 to >1500 mg day(-1) . Thus, supplements are not needed within this range of intakes to compensate for a demonstrable dietary deficiency, but might be acting as weak anti-resorptive agents via effects on parathyroid hormone and calcitonin. Consistent with this, supplements do acutely reduce bone resorption and produce small short-term effects on bone density, without evidence of a cumulative density benefit. As a result, anti-fracture efficacy remains unproven, with no evidence to support hip fracture prevention (other than in a cohort with severe vitamin D deficiency) and total fracture numbers are reduced by 0-10%, depending on which meta-analysis is considered. Five recent large studies have failed to demonstrate fracture prevention in their primary analyses. This must be balanced against an increase in gastrointestinal side effects (including a doubling of hospital admissions for these problems), a 17% increase in renal calculi and a 20-40% increase in risk of myocardial infarction. Each of these adverse events alone neutralizes any possible benefit in fracture prevention. Thus, calcium supplements appear to have a negative risk-benefit effect, and so should not be used routinely in the prevention or treatment of osteoporosis. PMID:26174589

  16. Calcium supplements: benefits and risks.

    PubMed

    Reid, I R; Bristow, S M; Bolland, M J

    2015-10-01

    Calcium is an essential element in the diet, but there is continuing controversy regarding its optimal intake, and its role in the pathogenesis of osteoporosis. Most studies show little evidence of a relationship between calcium intake and bone density, or the rate of bone loss. Re-analysis of data from the placebo group from the Auckland Calcium Study demonstrates no relationship between dietary calcium intake and rate of bone loss over 5 years in healthy older women with intakes varying from <400 to >1500 mg day(-1) . Thus, supplements are not needed within this range of intakes to compensate for a demonstrable dietary deficiency, but might be acting as weak anti-resorptive agents via effects on parathyroid hormone and calcitonin. Consistent with this, supplements do acutely reduce bone resorption and produce small short-term effects on bone density, without evidence of a cumulative density benefit. As a result, anti-fracture efficacy remains unproven, with no evidence to support hip fracture prevention (other than in a cohort with severe vitamin D deficiency) and total fracture numbers are reduced by 0-10%, depending on which meta-analysis is considered. Five recent large studies have failed to demonstrate fracture prevention in their primary analyses. This must be balanced against an increase in gastrointestinal side effects (including a doubling of hospital admissions for these problems), a 17% increase in renal calculi and a 20-40% increase in risk of myocardial infarction. Each of these adverse events alone neutralizes any possible benefit in fracture prevention. Thus, calcium supplements appear to have a negative risk-benefit effect, and so should not be used routinely in the prevention or treatment of osteoporosis.

  17. Augmented force output in skeletal muscle fibres of Xenopus following a preceding bout of activity.

    PubMed Central

    Bruton, J D; Westerblad, H; Katz, A; Lännergren, J

    1996-01-01

    1. The effect of a brief period of activity on subsequent isometric tetanic force production was investigated in single muscle fibres of Xenopus laevis. 2. Following a train of ten tetani separated by 4 s intervals, tetanic force was significantly augmented by about 10%. The tetanic force augmentation persisted for at least 15 min and then slowly subsided. A similar potentiation was seen following trains of five and twenty tetani. 3. During the period of tetanic force potentiation, tetanic calcium was reduced by more than 30%, and intracellular pH was reduced from 7.15 +/- 0.07 to 7.03 +/- 0.11 (n = 4). 4. Fibre swelling was greatest at 1 min and then subsided over 15-20 min and possibly accounted for a small part of the observed force potentiation. 5. A reduction in the inorganic phosphate (P1) concentration of more than 40% was found in fibres frozen in liquid nitrogen at the peak of force potentiation compared with resting fibres. 6. It is concluded that the augmentation of tetanic force found after a brief preceding bout of activity is due to a reduction in inorganic phosphate. This mechanism may underlie the improved performance observed in athletes after warm-up. Images Figure 2 PMID:8735706

  18. Possible deep fault slip preceding the 2004 Parkfield earthquake, inferred from detailed observations of tectonic tremor

    USGS Publications Warehouse

    Shelly, D.R.

    2009-01-01

    Earthquake predictability depends, in part, on the degree to which sudden slip is preceded by slow aseismic slip. Recently, observations of deep tremor have enabled inferences of deep slow slip even when detection by other means is not possible, but these data are limited to certain areas and mostly the last decade. The region near Parkfield, California, provides a unique convergence of several years of high-quality tremor data bracketing a moderate earthquake, the 2004 magnitude 6.0 event. Here, I present detailed observations of tectonic tremor from mid-2001 through 2008 that indicate deep fault slip both before and after the Parkfield earthquake that cannot be detected with surface geodetic instruments. While there is no obvious short-term precursor, I find unidirectional tremor migration accompanied by elevated tremor rates in the 3 months prior to the earthquake, which suggests accelerated creep on the fault ???16 km beneath the eventual earthquake hypocenter. Copyright 2009 by the American Geophysical Union.

  19. The tailings dam failure of 5 November 2015 in SE Brazil and its preceding seismic sequence

    NASA Astrophysics Data System (ADS)

    Agurto-Detzel, H.; Bianchi, M.; Assumpção, M.; Schimmel, M.; Collaço, B.; Ciardelli, C.; Barbosa, J. R.; Calhau, J.

    2016-05-01

    The collapse of a mine tailings dam and subsequent flood in SE Brazil on 5 November 2015 was preceded by a small-magnitude seismic sequence. In this report, we explore the spatiotemporal associations between the seismic events and the accident and discuss their possible connection. We also analyze the signals generated by the turbulent mudflow, as recorded by the Brazilian Seismographic Network (RSBR). In light of our observations, we propose as possible contributing factor for the dam collapse either ground shaking and/or soil liquefaction triggered by the earthquakes. The possibility of such a small-magnitude earthquake contributing to the collapse of a tailings dam raises important concerns regarding safety and related legislation of dams in Brazil and the world.

  20. Energy crisis precedes global metabolic failure in a novel Caenorhabditis elegans Alzheimer Disease model

    PubMed Central

    Fong, Sheng; Teo, Emelyne; Ng, Li Fang; Chen, Ce-Belle; Lakshmanan, Lakshmi Narayanan; Tsoi, Sau Yee; Moore, Philip Keith; Inoue, Takao; Halliwell, Barry; Gruber, Jan

    2016-01-01

    Alzheimer Disease (AD) is a progressive neurological disorder characterized by the deposition of amyloid beta (Aβ), predominantly the Aβ1–42 form, in the brain. Mitochondrial dysfunction and impaired energy metabolism are important components of AD pathogenesis. However, the causal and temporal relationships between them and AD pathology remain unclear. Using a novel C. elegans AD strain with constitutive neuronal Aβ1–42 expression that displays neuromuscular defects and age-dependent behavioural dysfunction reminiscent of AD, we have shown that mitochondrial bioenergetic deficit is an early event in AD pathogenesis, preceding dysfunction of mitochondrial electron transfer chain (ETC) complexes and the onset of global metabolic failure. These results are consistent with an emerging view that AD may be a metabolic neurodegenerative disease, and also confirm that Aβ-driven metabolic and mitochondrial effects can be reproduced in organisms separated by large evolutionary distances. PMID:27653553

  1. Expectations from preceding prosody influence segmentation in online sentence processing.

    PubMed

    Brown, Meredith; Salverda, Anne Pier; Dilley, Laura C; Tanenhaus, Michael K

    2011-12-01

    Previous work examining prosodic cues in online spoken-word recognition has focused primarily on local cues to word identity. However, recent studies have suggested that utterance-level prosodic patterns can also influence the interpretation of subsequent sequences of lexically ambiguous syllables (Dilley, Mattys, & Vinke, Journal of Memory and Language, 63:274-294, 2010; Dilley & McAuley, Journal of Memory and Language, 59:294-311, 2008). To test the hypothesis that these distal prosody effects are based on expectations about the organization of upcoming material, we conducted a visual-world experiment. We examined fixations to competing alternatives such as pan and panda upon hearing the target word panda in utterances in which the acoustic properties of the preceding sentence material had been manipulated. The proportions of fixations to the monosyllabic competitor were higher beginning 200 ms after target word onset when the preceding prosody supported a prosodic constituent boundary following pan-, rather than following panda. These findings support the hypothesis that expectations based on perceived prosodic patterns in the distal context influence lexical segmentation and word recognition.

  2. Does lumbar facet arthrosis precede disc degeneration? A postmortem study.

    PubMed

    Eubanks, Jason David; Lee, Michael J; Cassinelli, Ezequiel; Ahn, Nicholas U

    2007-11-01

    It is believed lumbar degeneration begins in the disc, where desiccation and collapse lead to instability and compensatory facet arthrosis. We explored the contrary contention that facet degeneration precedes disc degeneration by examining 647 skeletal lumbar spines. Using facet osteophytosis as a measure of facet degeneration and vertebral rim osteophytosis as a measure of disc degeneration, we assumed bone degeneration in both locations equally reflected the progression of those in the soft tissues. We graded arthrosis Grade 0 to 4 on a continuum from no arthritis to ankylosis. The data were analyzed for different age groups to examine patterns of degeneration with age. Specimens younger than 30 years of age had a higher prevalence of facet osteophytosis compared with vertebral rim osteophotosis at L1-L2 and L2-L3. Specimens aged 30 to 39 years showed more facet osteophytosis than vertebral rim osteophytosis at L4-L5. Specimens older than 40 years, however, showed more vertebral rim osteophytosis compared with facet osteophytosis at all levels except L4-L5 and L5-S1. This skeletal study suggests facet osteophytosis appears early in the degenerative process, preceding vertebral rim osteophytosis of degenerating intervertebral discs. However, once facets begin deteriorating with age, vertebral rim osteophytosis overtakes continued facet osteophytosis. These data challenge the belief that facet osteophytosis follows vertebral rim osteophytosis; rather, it appears vertebral rim osteophytosis progresses more rapidly in later years, but facet osteophotosis occurs early, predominating in younger individuals.

  3. Expectations from preceding prosody influence segmentation in online sentence processing

    PubMed Central

    Brown, Meredith; Salverda, Anne Pier; Dilley, Laura C.; Tanenhaus, Michael K.

    2013-01-01

    Previous work examining prosodic cues in online spoken-word recognition has focused primarily on local cues to word identity. However, recent studies have suggested that utterance-level prosodic patterns can also influence the interpretation of subsequent sequences of lexically ambiguous syllables (Dilley, Mattys, & Vinke, Journal of Memory and Language, 63:274–294, 2010; Dilley & McAuley, Journal of Memory and Language, 59:294–311, 2008). To test the hypothesis that these distal prosody effects are based on expectations about the organization of upcoming material, we conducted a visual-world experiment. We examined fixations to competing alternatives such as pan and panda upon hearing the target word panda in utterances in which the acoustic properties of the preceding sentence material had been manipulated. The proportions of fixations to the monosyllabic competitor were higher beginning 200 ms after target word onset when the preceding prosody supported a prosodic constituent boundary following pan-, rather than following panda. These findings support the hypothesis that expectations based on perceived prosodic patterns in the distal context influence lexical segmentation and word recognition. PMID:21968925

  4. Selective attention in the honeybee optic lobes precedes behavioral choices.

    PubMed

    Paulk, Angelique C; Stacey, Jacqueline A; Pearson, Thomas W J; Taylor, Gavin J; Moore, Richard J D; Srinivasan, Mandyam V; van Swinderen, Bruno

    2014-04-01

    Attention allows animals to respond selectively to competing stimuli, enabling some stimuli to evoke a behavioral response while others are ignored. How the brain does this remains mysterious, although it is increasingly evident that even animals with the smallest brains display this capacity. For example, insects respond selectively to salient visual stimuli, but it is unknown where such selectivity occurs in the insect brain, or whether neural correlates of attention might predict the visual choices made by an insect. Here, we investigate neural correlates of visual attention in behaving honeybees (Apis mellifera). Using a closed-loop paradigm that allows tethered, walking bees to actively control visual objects in a virtual reality arena, we show that behavioral fixation increases neuronal responses to flickering, frequency-tagged stimuli. Attention-like effects were reduced in the optic lobes during replay of the same visual sequences, when bees were not able to control the visual displays. When bees were presented with competing frequency-tagged visual stimuli, selectivity in the medulla (an optic ganglion) preceded behavioral selection of a stimulus, suggesting that modulation of early visual processing centers precedes eventual behavioral choices made by these insects.

  5. Physiological and psychophysical modeling of the precedence effect.

    PubMed

    Xia, Jing; Brughera, Andrew; Colburn, H Steven; Shinn-Cunningham, Barbara

    2010-09-01

    Many past studies of sound localization explored the precedence effect (PE), in which a pair of brief, temporally close sounds from different directions is perceived as coming from a location near that of the first-arriving sound. Here, a computational model of low-frequency inferior colliculus (IC) neurons accounts for both physiological and psychophysical responses to PE click stimuli. In the model, IC neurons have physiologically plausible inputs, receiving excitation from the ipsilateral medial superior olive (MSO) and long-lasting inhibition from both ipsilateral and contralateral MSOs, relayed through the dorsal nucleus of the lateral lemniscus. In this model, physiological suppression of the lagging response depends on the inter-stimulus delay (ISD) between the lead and lag as well as their relative locations. Psychophysical predictions are generated from a population of model neurons. At all ISDs, predicted lead localization is good. At short ISDs, the estimated location of the lag is near that of the lead, consistent with subjects perceiving both lead and lag from the lead location. As ISD increases, the estimated lag location moves closer to the true lag location, consistent with listeners' perception of two sounds from separate locations. Together, these simulations suggest that location-dependent suppression in IC neurons can explain the behavioral phenomenon known as the precedence effect.

  6. Selective attention in the honeybee optic lobes precedes behavioral choices

    PubMed Central

    Paulk, Angelique C.; Stacey, Jacqueline A.; Pearson, Thomas W. J.; Taylor, Gavin J.; Moore, Richard J. D.; Srinivasan, Mandyam V.; van Swinderen, Bruno

    2014-01-01

    Attention allows animals to respond selectively to competing stimuli, enabling some stimuli to evoke a behavioral response while others are ignored. How the brain does this remains mysterious, although it is increasingly evident that even animals with the smallest brains display this capacity. For example, insects respond selectively to salient visual stimuli, but it is unknown where such selectivity occurs in the insect brain, or whether neural correlates of attention might predict the visual choices made by an insect. Here, we investigate neural correlates of visual attention in behaving honeybees (Apis mellifera). Using a closed-loop paradigm that allows tethered, walking bees to actively control visual objects in a virtual reality arena, we show that behavioral fixation increases neuronal responses to flickering, frequency-tagged stimuli. Attention-like effects were reduced in the optic lobes during replay of the same visual sequences, when bees were not able to control the visual displays. When bees were presented with competing frequency-tagged visual stimuli, selectivity in the medulla (an optic ganglion) preceded behavioral selection of a stimulus, suggesting that modulation of early visual processing centers precedes eventual behavioral choices made by these insects. PMID:24639490

  7. Arterial stiffening precedes systolic hypertension in diet-induced obesity.

    PubMed

    Weisbrod, Robert M; Shiang, Tina; Al Sayah, Leona; Fry, Jessica L; Bajpai, Saumendra; Reinhart-King, Cynthia A; Lob, Heinrich E; Santhanam, Lakshmi; Mitchell, Gary; Cohen, Richard A; Seta, Francesca

    2013-12-01

    Stiffening of conduit arteries is a risk factor for cardiovascular morbidity. Aortic wall stiffening increases pulsatile hemodynamic forces that are detrimental to the microcirculation in highly perfused organs, such as the heart, brain, and kidney. Arterial stiffness is associated with hypertension but presumed to be due to an adaptive response to increased hemodynamic load. In contrast, a recent clinical study found that stiffness precedes and may contribute to the development of hypertension although the mechanisms underlying hypertension are unknown. Here, we report that in a diet-induced model of obesity, arterial stiffness, measured in vivo, develops within 1 month of the initiation of the diet and precedes the development of hypertension by 5 months. Diet-induced obese mice recapitulate the metabolic syndrome and are characterized by inflammation in visceral fat and aorta. Normalization of the metabolic state by weight loss resulted in return of arterial stiffness and blood pressure to normal. Our findings support the hypothesis that arterial stiffness is a cause rather than a consequence of hypertension.

  8. Calcium and calcium isotope changes during carbon cycle perturbations at the end-Permian

    NASA Astrophysics Data System (ADS)

    Komar, N.; Zeebe, R. E.

    2016-01-01

    Negative carbon and calcium isotope excursions, as well as climate shifts, took place during the most severe mass extinction event in Earth's history, the end-Permian (˜252 Ma). Investigating the connection between carbon and calcium cycles during transient carbon cycle perturbation events, such as the end-Permian, may help resolve the intricacies between the coupled calcium-carbon cycles, as well as provide a tool for constraining the causes of mass extinction. Here we identify the deficiencies of a simplified calcium model employed in several previous studies, and we demonstrate the importance of a fully coupled carbon cycle model when investigating the dynamics of carbon and calcium cycling. Simulations with a modified version of the Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir model, which includes a fully coupled carbon-calcium cycle, indicate that increased weathering rates and ocean acidification (potentially caused by Siberian Trap volcanism) are not capable of producing trends observed in the record, as previously claimed. Our model results suggest that combined effects of carbon input via Siberian Trap volcanism (12,000 Pg C), the cessation of biological carbon export, and variable calcium isotope fractionation (due to a change in the seawater carbonate ion concentration) represents a more plausible scenario. This scenario successfully reconciles δ13C and δ44Ca trends observed in the sediment record, as well as the proposed warming of >6°C.

  9. Calcium and calcium isotope changes during carbon cycle perturbations at the end-Permian

    NASA Astrophysics Data System (ADS)

    Komar, Nemanja; Zeebe, Richard

    2016-04-01

    Negative carbon and calcium isotope excursions, as well as climate shifts, took place during the most severe mass extinction event in Earth's history, the end-Permian (˜252 Ma). Investigating the connection between carbon and calcium cycles during transient carbon cycle perturbation events, such as the end-Permian, may help resolve the intricacies between the coupled calcium-carbon cycles, as well as provide a tool for constraining the causes of mass extinction. Here, we identify the deficiencies of a simplified calcium model employed in several previous studies and we demonstrate the importance of a fully coupled carbon-cycle model when investigating the dynamics of carbon and calcium cycling. Simulations with a modified version of the LOSCAR model, which includes a fully coupled carbon-calcium cycle, indicate that increased weathering rates and ocean acidification (potentially caused by Siberian Trap volcanism) are not capable of producing trends observed in the record, as previously claimed. Our model results suggest that combined effects of carbon input via Siberian Trap volcanism (12,000 Pg C), the cessation of biological carbon export, and variable calcium isotope fractionation (due to a change in the seawater carbonate ion concentration) represents a more plausible scenario. This scenario successfully reconciles δ13C and δ44Ca trends observed in the sediment record, as well as the proposed warming of >6oC.

  10. Mitochondria: the calcium connection.

    PubMed

    Contreras, Laura; Drago, Ilaria; Zampese, Enrico; Pozzan, Tullio

    2010-01-01

    Calcium handling by mitochondria is a key feature in cell life. It is involved in energy production for cell activity, in buffering and shaping cytosolic calcium rises and also in determining cell fate by triggering or preventing apoptosis. Both mitochondria and the mechanisms involved in the control of calcium homeostasis have been extensively studied, but they still provide researchers with long-standing or even new challenges. Technical improvements in the tools employed for the investigation of calcium dynamics have been-and are still-opening new perspectives in this field, and more prominently for mitochondria. In this review we present a state-of-the-art toolkit for calcium measurements, with major emphasis on the advantages of genetically encoded indicators. These indicators can be efficiently and selectively targeted to specific cellular sub-compartments, allowing previously unavailable high-definition calcium dynamic studies. We also summarize the main features of cellular and, in more detail, mitochondrial calcium handling, especially focusing on the latest breakthroughs in the field, such as the recent direct characterization of the calcium microdomains that occur on the mitochondrial surface upon cellular stimulation. Additionally, we provide a major example of the key role played by calcium in patho-physiology by briefly describing the extensively reported-albeit highly controversial-alterations of calcium homeostasis in Alzheimer's disease, casting lights on the possible alterations in mitochondrial calcium handling in this pathology.

  11. Calcium signaling and epilepsy.

    PubMed

    Steinlein, Ortrud K

    2014-08-01

    Calcium signaling is involved in a multitude of physiological and pathophysiological mechanisms. Over the last decade, it has been increasingly recognized as an important factor in epileptogenesis, and it is becoming obvious that the excess synchronization of neurons that is characteristic for seizures can be linked to various calcium signaling pathways. These include immediate effects on membrane excitability by calcium influx through ion channels as well as delayed mechanisms that act through G-protein coupled pathways. Calcium signaling is able to cause hyperexcitability either by direct modulation of neuronal activity or indirectly through calcium-dependent gliotransmission. Furthermore, feedback mechanisms between mitochondrial calcium signaling and reactive oxygen species are able to cause neuronal cell death and seizures. Unravelling the complexity of calcium signaling in epileptogenesis is a daunting task, but it includes the promise to uncover formerly unknown targets for the development of new antiepileptic drugs.

  12. Effect of oat bran muffins on calcium absorption and calcium, phosphorus, magnesium and zinc balance in men.

    PubMed

    Spencer, H; Norris, C; Derler, J; Osis, D

    1991-12-01

    Metabolic balance studies were conducted in adult human males to investigate the effect of oat bran on the nitrogen, calcium, phosphorus, magnesium and zinc balance, on the intestinal absorption of calcium and on the endogenous fecal calcium, using 47CaCl2 as the tracer. A 40-d control period preceded a 32-d experimental period in which subjects consumed four oat bran muffins daily as part of a constant metabolic diet. No significant changes in the calcium, magnesium or zinc balances were observed, but the nitrogen and phosphorus balances increased. The net or apparent absorption of nitrogen, magnesium and phosphorus expressed per milligram of intake increased significantly in the oat bran period due to the added content of these nutrients in the oat bran muffins. The intake of the oat bran muffins led to a significant increase in urinary phosphorus and significant decreases in urinary calcium and 47Ca excretions. The intestinal absorption of calcium, determined with 47Ca, did not change, whereas the endogenous fecal calcium increased slightly but significantly.

  13. Changes in autonomic activity preceding onset of nonsustained ventricular tachycardia

    NASA Technical Reports Server (NTRS)

    Osaka, M.; Saitoh, H.; Sasabe, N.; Atarashi, H.; Katoh, T.; Hayakawa, H.; Cohen, R. J.

    1996-01-01

    Background: The triggering role of the autonomic nervous system in the initiation of ventricular tachycardia has not been established. To investigate the relationship between changes in autonomic activity and the occurrence of nonsustained ventricular tachycardia (NSVT) we examined heart rate variability (HRV) during the 2-hour period preceding spontaneous episodes of NSVT. Twenty-four subjects were identified retrospectively as having had one episode of NSVT during 24-hour Holter ECC recording. Methods: We measured the mean interval between normal heats (meanRR), the standard deviation of the intervals between beats (SD), the percentage of counts of sequential intervals between normal beats with a change of >50 ms (%RR50), the logarithms of low- and high-frequency spectral components (lnLF, lnHF) of HRV for sequential 10-minute segments preceding NSVT. The correlation dimension (CDim) of HRV was calculated similarly for sequential 20-minute segments. We assessed the significance of the time-course change of each marker over the 120-minute period prior to NSVT onset. Results: MeanRR (P < 0.05), lnLF (P < 0.0001), lnHF (P < 0.0001), the natural logarithm of the ratio of LF to HF (ln[LF/HF]; P < 0.05), and CDim (P < 0.05) showed significant time-course changes during that period, while SD and %RR50 did not. MeanRR, lnLF, lnHF, and CDim all decreased prior to the onset of NSVT, whereas ln(LF/HF) increased. We divided the subjects into two groups: one consisting of 12 patients with coronary artery disease; and the second group of 12 patients without known coronary artery disease. Both groups showed significant changes (P < 0.05) of CDim, lnLF, and lnHF preceding the episodes of NSVT. Conclusions: Changes in the pattern of HRV prior to the onset of episodes of NSVT suggest that changes in autonomic activity may commonly play a role in the triggering of spontaneous episodes of NSVT in susceptible patients. The measured changes suggest a reduction in parasympathetic

  14. 22 CFR 42.68 - Informal evaluation of family members if principal applicant precedes them.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... principal applicant precedes them. 42.68 Section 42.68 Foreign Relations DEPARTMENT OF STATE VISAS VISAS... Visas § 42.68 Informal evaluation of family members if principal applicant precedes them. (a) Preliminary determination of visa eligibility. If a principal applicant proposes to precede the family to...

  15. Revisiting Precede-Proceed: A Leading Model for Ecological and Ethical Health Promotion

    ERIC Educational Resources Information Center

    Porter, Christine M.

    2016-01-01

    Background: The Precede-Proceed model has provided moral and practical guidance for the fields of health education and health promotion since Lawrence Green first developed Precede in 1974 and Green and Kreuter added Proceed in 1991. Precede-Proceed today remains the most comprehensive and one of the most used approaches to promoting health.…

  16. Decision Preceding Negativity in the Iowa Gambling Task: An ERP study

    ERIC Educational Resources Information Center

    Bianchin, Marta; Angrilli, Alessandro

    2011-01-01

    The present study aimed to investigate the slow negative potential (termed Decision Preceding Negativity, DPN, from the family of the Readiness Potential) which precedes a willed risky decision. To this end, evoked potentials preceding and following an economic choice were measured in a sample of 16 male students during the Iowa Gambling Task…

  17. Smoking, calcium, calcium antagonists, and aging.

    PubMed

    Nicita-Mauro, V

    1990-01-01

    Aging is characterized, besides other changes, by a progressive increase in calcium content in the arterial wall, which is enhanced by diabetes mellitus, osteoporosis, arterial hypertension, and tabagism. As to tabagism, experiments in animals have shown that nicotine can increase calcium content of the arterial wall, and clinical studies have demonstrated that cigarette smoking induces peripheral vasoconstriction, with consequent increase in blood pressure levels. In order to study the role of calcium ions in the pathogenesis of the vasoconstrictive lesions caused by "acute" smoking, the author has studied the peripheral vascular effects of the calcium-channel antagonist nifedipine, a dihydropyridine derivative, and calcitonin, a hypocalcemizing hormone which possess vasoactive actions on 12 elderly regular smokers (mean age 65.8 years). The results demonstrated that both nifedipine (10 mg sublingually 20 min before smoking) and salmon calcitonin (100 MRC U/daily intramuscularly for three days) are able to prevent peripheral vasoconstriction evaluated by Doppler velocimetry, as well as the increase of blood pressure induced by smoking. On the basis of our results, the author proposes that cigarette smoking-induced vasoconstriction is a calcium-mediated process, which can be hindered by drugs with calcium antagonist action. PMID:2226675

  18. Calcium intake is not associated with increased coronary artery calcification: The Framingham Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adequate calcium intake is known to protect the skeleton. However, studies that have reported adverse effects of calcium supplementation on vascular events have raised widespread concern. We assessed the association between calcium intake (from diet and supplements) and coronary artery calcification...

  19. Electrical polarity in embryos of wild carrot precedes cotyledon differentiation.

    PubMed

    Brawley, S H; Wetherell, D F; Robinson, K R

    1984-10-01

    Endogenous electrical currents traverse embryos of a higher plant, the wild carrot Daucus carota L. Current enters the apical pole and leaves the region near the presumptive radicle in the radially symmetric globular embryo. Current also enters the exposed surfaces of incipient globular embryos. This electrical polarity precedes differentiation of vascular tissue and cotyledon development. Localized current is observed at both growing ends of the embryos in subsequent stages of embryogenesis. Inward current is found at the cotyledons; outward current is found at the radicle/root. Exogenous indole-3-acetic acid (3 muM) reversibly inhibits these currents. Little current traverses the surface of intermediate regions of the embryo. The ionic gradients generated by these currents may be important in accumulation of metabolites and in other developmental processes within the embryo.

  20. [The influences of laterality on global precedence: interference effects].

    PubMed

    Kimura, Jun

    2008-02-01

    This study aimed to clarify the influence of laterality on interference effects for global precedence, and to examine the mechanism of these effects. In most previous studies, the neutral condition was excluded from the consistency factor and the difference of latencies between the consistent and inconsistent conditions was regarded as the interference score, which may not be accurate. In this study, the difference of latencies between the neutral and the inconsistent condition was regarded as the interference score. The results of the analysis of variance (ANOVA) for latencies showed that interference effects influenced only right visual field-left hemisphere (RVF-LH), and facilitation effects influenced only left visual field-right hemisphere (LVF-RH) in the local condition. These findings indicate that it does not matter how optimal processing influenced interference effects on suboptimal processing in each hemisphere, for example how global processing influenced local processing in the right hemisphere, but rather how each hemisphere controlled optimal processing.

  1. Solar wind iron charge states preceding a driver plasma

    NASA Technical Reports Server (NTRS)

    Galvin, A. B.; Ipavich, F. M.; Gloeckler, G.; Hovestadt, D.; Tsurutani, B. T.

    1987-01-01

    Iron and silicon/sulfur charge state and velocity measurements and iron density measurements in the shocked solar wind which preceded the flare-related driver plasma observed on September 29, 1978 by ISEE 3 are reported. Given the assumption that the driver plasma is magnetically isolated from the ambient solar wind, the contact surface separating these two plasma regimes is expected to form an distinct boundary in the charge state composition. Instead, an apparent transition in the ionization state of the shocked solar wind from ambient solar wind values to those typical of the driver plasma is observed. This result may reflect X-ray ionization of the solar wind plasma near the flare site.

  2. The physics of charge separation preceding lightning strokes in thunderclouds

    NASA Technical Reports Server (NTRS)

    Kyrala, Ali

    1987-01-01

    The physics of charge separation preceding lightning strokes in thunderclouds is presented by three types of arguments: An explanation is given for the aggregation of electrical charges of like sign overcoming Coulomb repulsion by attraction due to exchange interaction. The latter is well known in quantum mechanics from the theories of the nuclear bond and the covalent bond. A classical electrostatic model of charge balls of segregated positive and negative charges in the thundercloud is presented. These charge balls can only be maintained in temporarily stable locations by a containing vortex. Because they will be of different sizes and masses, they will stabilize at different altitudes when drag forces are included with the given electrostatic force. The question of how the charges become concentrated again after lightning discharges is approached by means of the collisional Boltzmann transport equation to explain quasi-periodic recharging. It is shown that solutions cannot be separable in both position and time if they are to represent aggregation.

  3. Modulation and action of the calcium-sensing receptor.

    PubMed

    Drüeke, Tilman B

    2004-08-01

    The discovery and cloning of the calcium-sensing receptor (CaR) in 1993 has led to a better understanding of the regulation of calcium homoeostasis. Following activation by extracellular calcium ions, the CaR triggers a cascade of intracellular events. These events result in the release of secondary messengers, which have a number of biological effects, the most important of which is a reduction in parathyroid hormone (PTH) secretion. The way in which calcium acts on the CaR varies depending on the cell type. In the parathyroid gland cell, activation of the CaR by elevated serum levels of calcium leads to a decrease in PTH secretion. In the kidney, CaR activation is thought to have several different actions, leading to enhanced reabsorption of sodium chloride and increased calcium and magnesium excretion in the renal tubules. CaRs are also found in other tissues in the body that are not involved in calcium homoeostasis, suggesting that the CaR has actions that are not associated with calcium homoeostasis. In patients with end-stage renal disease, parathyroid gland hyperplasia is associated with downregulation of the CaR. Discovery of the CaR has allowed the development of a group of drugs called calcimimetics, which mimic or potentiate the actions of extracellular calcium on the CaR. These compounds have considerable potential for the treatment of primary and secondary hyperparathyroidism. PMID:15284356

  4. Cellular Mechanisms of Calcium-Mediated Triggered Activity

    NASA Astrophysics Data System (ADS)

    Song, Zhen

    proteins. How those various factors interact synergistically to promote DADs is not well understood. Furthermore, at an even more basic level, it remains unclear to what degree spontaneous Ca2+ release and the appearance of DADs are deterministic, meaning reproducible under identical conditions, or inherently stochastic like nucleation in the physical context of phase transitions. In this thesis, we use and further develop a biologically detailed computational model to investigate basic aspects of TA in isolated heart cells (cardiac myocytes). Isolated cells can be obtained by enzymatic dissociation of heart tissue and studied experimentally using standard electrophysiological recording methods and confocal imaging of Ca2+ dynamics. Hence they provide a well controlled setting to investigate the generation of DADs under well controlled conditions. Our computational model captures essential aspects of the hierarchical architecture of ventricular myocytes, which consists of a large number of approximately 20,000 to 50,000 regularly spaced submicron regions containing clusters of 50-100 Ryanodine receptor (RyR) Ca2+ release channels. Each of those regions acts as a discrete "calcium release unit'' (CRU). Therefore our model allows us to address for the first time quantitatively the fundamental question of whether Ca2+ release, which is highly stochastic at the level of a single calcium release unit, is stochastic or deterministic at the whole cell level where the Ca 2+ signal is the summation of releases from a large number of units. Addressing this question is the focus of the first part of this thesis. Our results demonstrate that both the initiation and termination of TA are highly stochastic at the whole cell level due to the spatiotemporal organization of discrete release events into multiple Ca2+ waves. Our results allow us to characterize the probability distributions that govern the number of DADs preceding a triggered action potential and the number of triggered

  5. Store-Operated Calcium Channels

    PubMed Central

    Lewis, Richard S.

    2015-01-01

    Store-operated calcium channels (SOCs) are a major pathway for calcium signaling in virtually all metozoan cells and serve a wide variety of functions ranging from gene expression, motility, and secretion to tissue and organ development and the immune response. SOCs are activated by the depletion of Ca2+ from the endoplasmic reticulum (ER), triggered physiologically through stimulation of a diverse set of surface receptors. Over 15 years after the first characterization of SOCs through electrophysiology, the identification of the STIM proteins as ER Ca2+ sensors and the Orai proteins as store-operated channels has enabled rapid progress in understanding the unique mechanism of store-operate calcium entry (SOCE). Depletion of Ca2+ from the ER causes STIM to accumulate at ER-plasma membrane (PM) junctions where it traps and activates Orai channels diffusing in the closely apposed PM. Mutagenesis studies combined with recent structural insights about STIM and Orai proteins are now beginning to reveal the molecular underpinnings of these choreographic events. This review describes the major experimental advances underlying our current understanding of how ER Ca2+ depletion is coupled to the activation of SOCs. Particular emphasis is placed on the molecular mechanisms of STIM and Orai activation, Orai channel properties, modulation of STIM and Orai function, pharmacological inhibitors of SOCE, and the functions of STIM and Orai in physiology and disease. PMID:26400989

  6. Extracellular calcium sensing and extracellular calcium signaling

    NASA Technical Reports Server (NTRS)

    Brown, E. M.; MacLeod, R. J.; O'Malley, B. W. (Principal Investigator)

    2001-01-01

    , localized changes in Ca(o)(2+) within the ECF can originate from several mechanisms, including fluxes of calcium ions into or out of cellular or extracellular stores or across epithelium that absorb or secrete Ca(2+). In any event, the CaR and other receptors/sensors for Ca(o)(2+) and probably for other extracellular ions represent versatile regulators of numerous cellular functions and may serve as important therapeutic targets.

  7. Information flow through calcium binding proteins

    NASA Astrophysics Data System (ADS)

    Bak, Ji Hyun; Bialek, William

    2013-03-01

    Calcium signaling is a ubiquitous mode of biological communication, which regulates a great variety of vital processes in living systems. Such a signal typically begins with an elementary event, in which calcium ions bind to a protein, inducing a change in the protein's structure. Information can only be lost, from what was conveyed through this initial event, as the signal is further transduced through the downstream networks. In the present work we analyze and optimize the information flow in the calcium binding process. We explicitly calculate the mutual information between the calcium concentration and the states of the protein, using a simple model for allosteric regulation in a dimeric protein. The optimal solution depends on the dynamic range of the input as well as on the timescale of signal integration. According to our result, the optimizing strategy involves allowing the calcium-binding protein to be ``activated'' by a partial occupation of its sites, and tuning independently the strengths of cooperative interactions in the binding and unbinding processes.

  8. Calcium use in the management of osteoporosis: continuing questions and controversies.

    PubMed

    Wilczynski, Cory; Camacho, Pauline

    2014-12-01

    Calcium is a vital element in the health and maintenance of growing and mature bone. The amount of calcium recommended for ingestion varies by age, and these requirements can be met by dietary sources or calcium supplementation. This article reviews the role of calcium in the body and the benefits and risks to calcium supplementation. The effects of calcium on fracture risk reduction, bone density, and bone turnover markers as well as the conflicting data on cardiovascular events and increased risk of nephrolithiasis associated with supplementation are discussed.

  9. Changes in Cx43 and NaV1.5 expression precede the occurrence of substantial fibrosis in calcineurin-induced murine cardiac hypertrophy.

    PubMed

    Fontes, Magda S C; Raaijmakers, Antonia J A; van Doorn, Tessa; Kok, Bart; Nieuwenhuis, Sylvia; van der Nagel, Roel; Vos, Marc A; de Boer, Teun P; van Rijen, Harold V M; Bierhuizen, Marti F A

    2014-01-01

    In mice, the calcium-dependent phosphatase calcineurin A (CnA) induces a transcriptional pathway leading to pathological cardiac hypertrophy. Interestingly, induction of CnA has been frequently noticed in human hypertrophic and failing hearts. Independently, the arrhythmia vulnerability of such hearts has been regularly associated with remodeling of parameters determining electrical conduction (expression level of connexin43 (Cx43) and NaV1.5, connective tissue architecture), for which the precise molecular basis and sequence of events is still unknown. Recently, we observed reduced Cx43 and NaV1.5 expression in 4-week old mouse hearts, overexpressing a constitutively active form of CnA (MHC-CnA model), but the order of events is still unknown. Therefore, three key parameters of conduction (Cx43, NaV1.5 and connective tissue expression) were characterized in MHC-CnA ventricles versus wild-type (WT) during postnatal development on a weekly basis. At postnatal week 1, CnA overexpression induced cardiac hypertrophy in MHC-CnA. Moreover, protein and RNA levels of both Cx43 and NaV1.5 were reduced by at least 50% as compared to WT. Cx43 immunoreactive signal was reduced at week 2 in MHC-CnA. At postnatal week 3, Cx43 was less phosphorylated and RNA level of Cx43 normalized to WT values, although the protein level was still reduced. Additionally, MHC-CnA hearts displayed substantial fibrosis relative to WT, which was accompanied by increased RNA levels for genes previously associated with fibrosis such as Col1a1, Col1a2, Col3a1, Tgfb1, Ctgf, Timp1 and microRNA miR-21. In MHC-CnA, reduction in Cx43 and NaV1.5 expression thus coincided with overexpression of CnA and hypertrophy development and preceded significant presence of fibrosis. At postnatal week 4 the alterations in conductional parameters observed in the MHC-CnA model lead to abnormal conduction and arrhythmias, similar to those observed in cardiac remodeling in heart failure patients. The MHC-CnA model, therefore

  10. Localization suppression and fusion measure of the precedence effect in young children

    NASA Astrophysics Data System (ADS)

    Litovsky, Ruth; Godar, Shelly; Yu, Gongqiang

    2001-05-01

    This study investigated aspects of the precedence effect (PE) known as fusion and localization dominance in children 4-5 years of age. Stimuli were three, 25-ms noise bursts (2-ms rise/fall times) with 250-ms ISI. On PE conditions the lead stimulus was presented from one of six locations in azimuth, and the lag was at 0 deg. Lead-lag delays varied from 5 to 100 ms. Localization was measured using an identification paradigm. Fusion was measured separately whereby subjects reported whether a single auditory event or two auditory events were perceived. Children reported two sounds on 75% of trials (fusion threshold) at delays ranging from 15 to 35 ms. Below fusion thresholds, the localization of the lead was similar to that of single-source stimuli. Above fusion thresholds lead localization was significantly degraded, persisting out to 100 ms. Localization of the lag was poor at all delays on which it was reported as being heard. According to these results localization dominance (difficulty localizing the lag) in children persists at greater delays than fusion, which is consistent with findings obtained in adult subjects. The range of delays over which these effects are robust in children is longer than the range observed in adults.

  11. Apoptosis induced in Jurkat cells by several agents is preceded by intracellular acidification.

    PubMed Central

    Gottlieb, R A; Nordberg, J; Skowronski, E; Babior, B M

    1996-01-01

    We have previously shown that in neutrophils deprived of granulocyte colony-stimulating factor, apoptosis is preceded by acidification and that the protection against apoptosis conferred on neutrophils by granulocyte colony-stimulating factor is dependent upon delay of this acidification. To test the hypothesis that acidification could be a general feature of apoptosis, we examined intracellular pH changes in another cell line. Jurkat cells, a T-lymphoblastoid line, were induced to undergo apoptosis with anti-Fas IgM, cycloheximide, or exposure to short-wavelength UV light. We found that acidification occurred in response to treatment with these agents and that acidification preceded DNA fragmentation. Jurkat cells were also found to possess an acid endonuclease that is active below pH 6.8, compatible with a possible role for this enzyme in chromatin digestion during apoptosis. Incubation of the cells with the bases imidazole or chloroquine during treatment with anti-Fas antibody or cycloheximide or after UV exposure decreased apoptosis as assessed by nuclear morphology and DNA content. The alkalinizing effect of imidazole and chloroquine was shown by the demonstration that the percentage of cells with an intracellular pH below 6.8 after treatment with anti-Fas antibody, cycloheximide, or UV was diminished in the presence of base as compared with similarly treated cells incubated in the absence of base. We conclude that acidification is an early event in programmed cell death and may be essential for genome destruction. Images Fig. 5 PMID:8570610

  12. Impaired nigrostriatal function precedes behavioral deficits in a genetic mitochondrial model of Parkinson's disease

    PubMed Central

    Good, Cameron H.; Hoffman, Alexander F.; Hoffer, Barry J.; Chefer, Vladimir I.; Shippenberg, Toni S.; Bäckman, Cristina M.; Larsson, Nils-Göran; Olson, Lars; Gellhaar, Sandra; Galter, Dagmar; Lupica, Carl R.

    2011-01-01

    Parkinson's disease (PD) involves progressive loss of nigrostriatal dopamine (DA) neurons over an extended period of time. Mitochondrial damage may lead to PD, and neurotoxins affecting mitochondria are widely used to produce degeneration of the nigrostriatal circuitry. Deletion of the mitochondrial transcription factor A gene (Tfam) in C57BL6 mouse DA neurons leads to a slowly progressing parkinsonian phenotype in which motor impairment is first observed at ∼12 wk of age. l-DOPA treatment improves motor dysfunction in these “MitoPark” mice, but this declines when DA neuron loss is more complete. To investigate early neurobiological events potentially contributing to PD, we compared the neurochemical and electrophysiological properties of the nigrostriatal circuit in behaviorally asymptomatic 6- to 8-wk-old MitoPark mice and age-matched control littermates. Release, but not uptake of DA, was impaired in MitoPark mouse striatal brain slices, and nigral DA neurons lacked characteristic pacemaker activity compared with control mice. Also, hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channel function was reduced in MitoPark DA neurons, although HCN messenger RNA was unchanged. This study demonstrates altered nigrostriatal function that precedes behavioral parkinsonian symptoms in this genetic PD model. A full understanding of these presymptomatic cellular properties may lead to more effective early treatments of PD.—Good, C. H., Hoffman, A. F., Hoffer, B. J., Chefer, V. I., Shippenberg, T. S., Bäckman, C. M., Larsson, N.-G., Olson, L., Gellhaar, S., Galter, D., Lupica, C. R. Impaired nigrostriatal function precedes behavioral deficits in a genetic mitochondrial model of Parkinson's disease. PMID:21233488

  13. Cerebral potentials preceding unilateral and simultaneous bilateral finger movements.

    PubMed

    Kristeva, R; Keller, E; Deecke, L; Kornhuber, H H

    1979-08-01

    Cerebral potentials preceding voluntary bilateral simultaneous finger movements were investigated in 19 right-handed young adult subjects, and were compared with unilateral right-sided finger m n the same experiment. With bilateral movements, the Bereitschaftspotential (BP) was not symmetrical or larger over the dominant hemisphere, but surprisingly, it was larger over the minor hemisphere. The BP averaged -3.66 microV (S.D. 1.96) over the left precentral region and -4.82 microV (S.D. 3.73) over the right precentral region in this condition. The difference was significant at 2P less than 0.01. This difference was pronounced in precentral leads but very small and almost missing in parietal leads. The pre-motion positivity (PMP) was well developed and even larger with bilateral than with unilateral (right-sides) movements. At the vertex it averaged +1.33 microV (S.D.4.16) with bilateral movements and only +0.15 microV (S.D. 1.42) with right-sided unilateral movements (2P less than 0.05). With bilateral movements the PMP could be observed in any record, but with unilateral movements it was missing at the left precentral lead, in accordance with previous publications (Deecke et al. 1969, 1976). The motor potential (MP), measured in a bipolar record from left and right precentral leads, was larger with unilateral (-1.25 microV, S.D. 1.33) than with bilateral movements (-0.36 microV, S.D. 0.92). Onset time differences of the BP preceding unilateral and bilateral movements were very small. However, there was a tendency towards earlier onset with unilateral than with bilateral movements (1031 msec, S.D. 358, as compared with 951 msec, S.D. 305). The averaged EMG revealed differences in movement onset. Muscular contraction tended to be earlier in the right than in the left m. flexor indicis in our right-handed subjects, on the average by 16 msec (S.D. 15). With unilateral right-sided movements, the left m. flexor indicis was not silent but showed an abortive mirror activity

  14. Lithospheric Convergence Preceded Extension in the Pannonian-Carpathian System

    NASA Astrophysics Data System (ADS)

    Houseman, Gregory; Stuart, Graham; Dando, Ben; Hetenyi, Gyorgy; Lorinczi, Piroska; Hegedus, Endre; Brueckl, Ewald

    2010-05-01

    The continuing collision of the Adriatic block with European continental lithosphere has its clearest expression now in the Alpine collision zone. Recent tomographic images of the upper mantle beneath the eastern Alps and western Pannonian Basin support the interpretation that in the Early Miocene the collision zone extended further east: a steeply dipping seismically fast structure stretches downward beneath the Eastern Alps reaching to the base of the transition zone, consistent with the long history of convergence in this region. This high velocity structure also extends eastward beneath the extensional Pannonian Basin. The high velocity anomaly beneath the Basin is strongly developed in transition zone depths (410 to 660 km) but the anomaly weakens upward. High velocities beneath the center of the extensional basin are unexpected because there is substantive evidence that the onset of extension in the Pannonian domain at around 17 Ma produced rapid extension of the lithosphere and replacement of the lower part of the lithosphere by hot asthenosphere. These deeper structures, however, must be explained by the long history of convergence that preceded the extension of the basin. Further evidence of a history of sustained convergence in the present Pannonian region is found in the depression of the 660 km seismic discontinuity beneath the Alps (Lombardi et al., EPSL, 2009) and also beneath the Pannonian Basin (Hetenyi et al., GRL, 2009). The 660 km discontinuity in both places is depressed by as much as 40 km, whereas the 410 km discontinuity is at approximately nominal depths. Evidently in both regions relatively dense material derived from the mid-Miocene collision sits stagnant on top of the 660 km discontinuity, where further descent is obstructed by the negative Clapeyron slope of the spinel-to-perovskite phase transition and/or the high viscosity of the lower mantle. The rapid extension of the Intra-Carpathian Basins in the Mid-Miocene (between about 17 and

  15. Slow Calcium Signals after Tetanic Electrical Stimulation in Skeletal Myotubes

    PubMed Central

    Eltit, José M.; Hidalgo, Jorge; Liberona, José L.; Jaimovich, Enrique

    2004-01-01

    The fluorescent calcium signal from rat myotubes in culture was monitored after field-stimulation with tetanic protocols. After the calcium signal sensitive to ryanodine and associated to the excitation-contraction coupling, a second long-lasting calcium signal refractory to ryanodine was consistently found. The onset kinetics of this slow signal were slightly modified in nominally calcium-free medium, as were both the frequency and number of pulses during tetanus. No signal was detected in the presence of tetrodotoxin. The participation of the dihydropyridine receptor (DHPR) as the voltage sensor for this signal was assessed by treatment with agonist and antagonist dihydropyridines (Bay K 8644 and nifedipine), showing an enhanced and inhibitory response, respectively. In the dysgenic GLT cell line, which lacks the α1S subunit of the DHPR, the signal was absent. Transfection of these cells with the α1S subunit restored the slow signal. In myotubes, the inositol 1,4,5-trisphosphate (IP3) mass increase induced by a tetanus protocol preceded in time the slow calcium signal. Both an IP3 receptor blocker and a phospholipase C inhibitor (xestospongin C and U73122, respectively) dramatically inhibit this signal. Long-lasting, IP3-generated slow calcium signals appear to be a physiological response to activity-related fluctuations in membrane potential sensed by the DHPR. PMID:15111418

  16. Safety of compounded calcium chloride admixtures for peripheral intravenous administration in the setting of a calcium gluconate shortage.

    PubMed

    Anger, Kevin E; Belisle, Caryn; Colwell, Megan B; Dannemiller, Robert; Alawadhi, Burhan; Wilkocki, Alex; Szumita, Paul M

    2014-10-01

    Calcium gluconate is preferred over calcium chloride for intravenous (IV) repletion of calcium deficiencies in the inpatient setting. In the setting of a national shortage of IV calcium gluconate, our institution implemented a compounded calcium chloride admixture for IV administration. The objective of this analysis is to evaluate the peripheral infusion site safety of compounded IV calcium chloride admixtures in adult inpatients. A total of 222 patients, encompassing 224 inpatient admissions, from April to June 2011 were retrospectively reviewed. Sterile preparations of calcium chloride in 5% dextrose (600 mg/250 mL and 300 mg/100 mL) were used during the study time period. Adverse infusion site reactions were assessed using an institutional infiltration and phlebitis grading system. A total of 333 doses were administered peripherally. In all, 4 (1.8%) patients experienced a moderate to severe infusion site reaction, with 3 due to phlebitis and 1 due to infiltration. Naranjo Nomogram for Adverse Drug Reaction Assessment classified all 4 reactions to have a possible link to calcium chloride administration. Peripheral administration of compounded calcium chloride admixtures in 5% dextrose is associated with a low incidence of IV infusion site reactions and can be considered as an alternative in the event of a calcium gluconate shortage.

  17. Mancozeb-induced behavioral deficits precede structural neural degeneration.

    PubMed

    Harrison Brody, A; Chou, Eunice; Gray, Janet M; Pokyrwka, Nancy J; Raley-Susman, Kathleen M

    2013-01-01

    Manganese-containing fungicides like Mancozeb have been associated with neurodegenerative conditions like Parkinson's disease. We examined the behavioral damage and differential neuronal vulnerability resulting from Mancozeb exposure using Caenorhabditis elegans, an important mid-trophic level soil organism that is also a powerful model for studying mechanisms of environmental pollutant-induced neurodegenerative disease. The dopamine-mediated swim to crawl locomotory transition behavior is exquisitely vulnerable to Mancozeb, with functional impairment preceding markers of neuronal structural damage. The damage is partially rescued in mutants lacking the divalent metal transporter, SMF-1, demonstrating that some, but not all, of the damage is mediated by manganese. Increasing concentrations of Mancozeb recruit additional behavioral dysfunction, notably serotonin-mediated egg-laying behavior, but without evident serotonergic neuronal structural damage. Thus, measurements of behavioral dysfunction are a sensitive early marker of fungicide toxicity that could be exploited to examine further mechanisms of neuron damage and possible therapeutic interventions. These results also provide important insight into the consequences of fungicide use on the ecological behavior of nematodes. PMID:23103283

  18. Joint shape morphogenesis precedes cavitation of the developing hip joint

    PubMed Central

    Nowlan, Niamh C; Sharpe, James

    2014-01-01

    The biology and mechanobiology of joint cavitation have undergone extensive investigation, but we have almost no understanding of the development of joint shape. Joint morphogenesis, the development of shape, has been identified as the ‘least understood aspect of joint formation’ (2005, Birth Defects Res C Embryo Today 75, 237), despite the clinical relevance of shape morphogenesis to postnatal skeletal malformations such as developmental dysplasia of the hip. In this study, we characterise development of early hip joint shape in the embryonic chick using direct capture 3D imaging. Contrary to formerly held assumptions that cavitation precedes morphogenesis in joint development, we have found that the major anatomical features of the adult hip are present at Hamburger Hamilton (HH)32, a full day prior to cavitation of the joint at HH34. We also reveal that the pelvis undergoes significant changes in orientation with respect to the femur, despite the lack of a joint cavity between the rudiments. Furthermore, we have identified the appearance of the ischium and pubis several developmental stages earlier than was previously reported, illustrating the value and importance of direct capture 3D imaging. PMID:24266523

  19. High rates of evolution preceded the origin of birds.

    PubMed

    Puttick, Mark N; Thomas, Gavin H; Benton, Michael J

    2014-05-01

    The origin of birds (Aves) is one of the great evolutionary transitions. Fossils show that many unique morphological features of modern birds, such as feathers, reduction in body size, and the semilunate carpal, long preceded the origin of clade Aves, but some may be unique to Aves, such as relative elongation of the forelimb. We study the evolution of body size and forelimb length across the phylogeny of coelurosaurian theropods and Mesozoic Aves. Using recently developed phylogenetic comparative methods, we find an increase in rates of body size and body size dependent forelimb evolution leading to small body size relative to forelimb length in Paraves, the wider clade comprising Aves and Deinonychosauria. The high evolutionary rates arose primarily from a reduction in body size, as there were no increased rates of forelimb evolution. In line with a recent study, we find evidence that Aves appear to have a unique relationship between body size and forelimb dimensions. Traits associated with Aves evolved before their origin, at high rates, and support the notion that numerous lineages of paravians were experimenting with different modes of flight through the Late Jurassic and Early Cretaceous.

  20. PRECEDENTS FOR AUTHORIZATION OF CONTENTS USING DOSE RATE MEASUREMENTS

    SciTech Connect

    Abramczyk, G.; Bellamy, S.; Nathan, S.; Loftin, B.

    2012-06-05

    For the transportation of Radioactive Material (RAM) packages, the requirements for the maximum allowed dose rate at the package surface and in its vicinity are given in Title 10 of the Code of Federal Regulations, Section 71.47. The regulations are based on the acceptable dose rates to which the public, workers, and the environment may be exposed. As such, the regulations specify dose rates, rather than quantity of radioactive isotopes and require monitoring to confirm the requirements are met. 10CFR71.47 requires that each package of radioactive materials offered for transportation must be designed and prepared for shipment so that under conditions normally incident to transportation the radiation level does not exceed 2 mSv/h (200 mrem/h) at any point on the external Surface of the package, and the transport index does not exceed 10. Before shipment, the dose rate of the package is determined by measurement, ensuring that it conforms to the regulatory limits, regardless of any analyses. This is the requirement for all certified packagings. This paper discusses the requirements for establishing the dose rates when shipping RAM packages and the precedents for meeting these requirements by measurement.

  1. Activation of ras oncogenes preceding the onset of neoplasia

    SciTech Connect

    Kumar, R.; Barbacid, M. ); Sukumar, S. )

    1990-06-01

    The identification of ras oncogenes in human and animal cancers including precancerous lesions indicates that these genes participate in the early stages of neoplastic development. Yet, these observations do not define the timing of ras oncogene activation in the multistep process of carcinogenesis. To ascertain the timing of ras oncogene activation, an animal model system was devised that involves the induction of mammary carcinomas in rats exposed at birth to the carcinogen nitrosomethylurea. High-resolution restriction fragment length polymorphism analysis of polymerase chain reaction-amplified ras sequences revealed the presence of both H-ras and K-ras oncogenes in normal mammary glands 2 weeks after carcinogen treatment and at least 2 months before the onset of neoplasia. These ras oncogenes can remain latent within the mammary gland until exposure to estrogens, demonstrating that activation of ras oncogenes can precede the onset of neoplasia and suggesting that normal physiological proliferative processes such as estrogen-induced mammary gland development may lead to neoplasia if the targeted cells harbor latent ras oncogenes.

  2. Bell's palsy: symptoms preceding and accompanying the facial paresis.

    PubMed

    De Seta, Daniele; Mancini, Patrizia; Minni, Antonio; Prosperini, Luca; De Seta, Elio; Attanasio, Giuseppe; Covelli, Edoardo; De Carlo, Andrea; Filipo, Roberto

    2014-01-01

    This individual prospective cohort study aims to report and analyze the symptoms preceding and accompanying the facial paresis in Bell's palsy (BP). Two hundred sixty-nine patients affected by BP with a maximum delay of 48 hours from the onset were enrolled in the study. The evolution of the facial paresis expressed as House-Brackmann grade in the first 10 days and its correlation with symptoms were analyzed. At the onset, 136 patients presented postauricular pain, 114 were affected by dry eye, and 94 reported dysgeusia. Dry mouth was present in 54 patients (19.7%), facial pain, hyperlacrimation, aural fullness, and hyperacusis represented a smaller percentage of the reported symptoms. After 10 days, 39.9% of the group had a severe paresis while 10.2% reached a complete recovery. Dry mouth at the onset was correlated with severe grade of palsy and was prognostic for poor recovery in the early period. These outcomes lead to the deduction that the nervus intermedius plays an important role in the presentation of the BP and it might be responsible for most of the accompanying symptomatology of the paresis. Our findings could be of important interest to early address a BP patient to further examinations and subsequent therapy.

  3. Neurological Evidence Linguistic Processes Precede Perceptual Simulation in Conceptual Processing

    PubMed Central

    Louwerse, Max; Hutchinson, Sterling

    2012-01-01

    There is increasing evidence from response time experiments that language statistics and perceptual simulations both play a role in conceptual processing. In an EEG experiment we compared neural activity in cortical regions commonly associated with linguistic processing and visual perceptual processing to determine to what extent symbolic and embodied accounts of cognition applied. Participants were asked to determine the semantic relationship of word pairs (e.g., sky – ground) or to determine their iconic relationship (i.e., if the presentation of the pair matched their expected physical relationship). A linguistic bias was found toward the semantic judgment task and a perceptual bias was found toward the iconicity judgment task. More importantly, conceptual processing involved activation in brain regions associated with both linguistic and perceptual processes. When comparing the relative activation of linguistic cortical regions with perceptual cortical regions, the effect sizes for linguistic cortical regions were larger than those for the perceptual cortical regions early in a trial with the reverse being true later in a trial. These results map upon findings from other experimental literature and provide further evidence that processing of concept words relies both on language statistics and on perceptual simulations, whereby linguistic processes precede perceptual simulation processes. PMID:23133427

  4. Calcium hydroxyapatite fillers.

    PubMed

    Tansavatdi, Kristina; Mangat, Devinder S

    2011-12-01

    Calcium hydroxyapatite fillers have unique advantages over other fillers in regards to duration of action and volume of product required for augmentation, especially in the midface and lower face. In this article, we describe our experience with calcium hydroxyapatite fillers and compare them with other available filler products.

  5. Southern Ocean frontal system changes precede Antarctic ice sheet growth during the middle Miocene

    NASA Astrophysics Data System (ADS)

    Kuhnert, Henning; Bickert, Torsten; Paulsen, Harald

    2009-07-01

    The middle Miocene climate approximately 14 Ma ago was characterized by the glaciation of Antarctica, deep-ocean cooling and variations in the global carbon cycle. Although the Southern Ocean underwent significant oceanographic changes, there is limited information on their spatial extent and timing. However, such knowledge is crucial for understanding the role of the Southern Ocean and the Antarctic Circumpolar Current (ACC) for Antarctic glaciation and the coupling between the ocean and continental climate. We have reconstructed surface temperatures and seawater oxygen isotopes at Ocean Drilling Program (ODP) Site 1092 in the Polar Frontal Zone of the Atlantic sector of the Southern Ocean from foraminiferal oxygen isotopes ( δ18O) and magnesium to calcium ratios (Mg/Ca). Sea surface cooling by ~ 4 °C and freshening indicated by the ~ 1‰ reduction of seawater δ18O ( δ18O sw) at 14.2 Ma precede the major step in Antarctic ice sheet growth at 13.8-13.9 Ma. This pattern qualitatively mirrors previous findings from the Pacific sector, and we interpret the surface hydrographic changes to reflect the circum-Antarctic northward shift of the Southern Ocean fronts and specifically at Site 1092 the passage of the Subantarctic Front. The magnitude of change in reconstructed δ18O sw requires a δ18O sw: salinity gradient significantly higher than the modern value (~ 0.52‰) and it possibly exceeded 1.1‰. This implies the Polar Frontal Zone was influenced by freshwater derived from Antarctica, which in turn confirms higher than modern continental precipitation. The latter has previously been suggested to have contributed to Antarctic glaciation.

  6. Combinatorial chemopreventive effect of butyric acid, nicotinamide and calcium glucarate against the 7,12-dimethylbenz(a)anthracene induced mouse skin tumorigenesis attained by enhancing the induction of intrinsic apoptotic events.

    PubMed

    Tiwari, Prakash; Sahay, Satya; Pandey, Manuraj; Qadri, Syed S Y H; Gupta, Krishna P

    2015-01-25

    We explored the basis of the combinatorial chemopreventive effect of butyric acid (BA), nicotinamide (NA) and calcium glucarate (CAG) on mouse skin exposed to 7,12-dimethylbenz(a)anthracene (DMBA). We studied the effects of topical application of DMBA in the presence or absence of BA, NA and CAG on the regulators of apoptosis. DMBA treatment suppressed Bax, Bax/Bcl-2 ratio, release of cyt c, Apaf1, caspase-9, -3 mediated apoptosis. Downregulation of p21 and upregulation of Bcl-2, mut p53 were also observed in only DMBA treated mice. Simultaneous application of BA, NA and CAG induced a mitochondria-mediated apoptosis, characterized by a rise in the Bax, Bax/Bcl-2 ratio, release of cyt c, upregulation of Apaf1 with down-stream activation of caspase-9, -3. Furthermore treatment with BA, NA and CAG demonstrated an upregulation of p21 and downregulation of Bcl-2, mut p53. But this effect was enhanced in the presence of all the three compounds together in combination. Chemoprevention by a combination of BA, NA and CAG by inducing the apoptosis, the natural cell death, suggest the importance of the potential combinational strategies capable of preventing skin tumor development.

  7. Combinatorial chemopreventive effect of butyric acid, nicotinamide and calcium glucarate against the 7,12-dimethylbenz(a)anthracene induced mouse skin tumorigenesis attained by enhancing the induction of intrinsic apoptotic events.

    PubMed

    Tiwari, Prakash; Sahay, Satya; Pandey, Manuraj; Qadri, Syed S Y H; Gupta, Krishna P

    2015-01-25

    We explored the basis of the combinatorial chemopreventive effect of butyric acid (BA), nicotinamide (NA) and calcium glucarate (CAG) on mouse skin exposed to 7,12-dimethylbenz(a)anthracene (DMBA). We studied the effects of topical application of DMBA in the presence or absence of BA, NA and CAG on the regulators of apoptosis. DMBA treatment suppressed Bax, Bax/Bcl-2 ratio, release of cyt c, Apaf1, caspase-9, -3 mediated apoptosis. Downregulation of p21 and upregulation of Bcl-2, mut p53 were also observed in only DMBA treated mice. Simultaneous application of BA, NA and CAG induced a mitochondria-mediated apoptosis, characterized by a rise in the Bax, Bax/Bcl-2 ratio, release of cyt c, upregulation of Apaf1 with down-stream activation of caspase-9, -3. Furthermore treatment with BA, NA and CAG demonstrated an upregulation of p21 and downregulation of Bcl-2, mut p53. But this effect was enhanced in the presence of all the three compounds together in combination. Chemoprevention by a combination of BA, NA and CAG by inducing the apoptosis, the natural cell death, suggest the importance of the potential combinational strategies capable of preventing skin tumor development. PMID:25478867

  8. Calcium and osteoporosis.

    PubMed

    Nordin, B E

    1997-01-01

    Calcium is an essential nutrient that is involved in most metabolic processes and the phosphate salts of which provide mechanical rigidity to the bones and teeth, where 99% of the body's calcium resides. The calcium in the skeleton has the additional role of acting as a reserve supply of calcium to meet the body's metabolic needs in states of calcium deficiency. Calcium deficiency is easily induced because of the obligatory losses of calcium via the bowel, kidneys, and skin. In growing animals, it may impair growth, delay consolidation of the skeleton, and in certain circumstances give rise to rickets but the latter is more often due to deficiency of vitamin D. In adult animals, calcium deficiency causes mobilization of bone and leads sooner or later to osteoporosis, i.e., a reduction in the "amount of bone in the bone" or apparent bone density. The effects of calcium deficiency and oophorectomy (ovariectomy) are additive. In humans, osteoporosis is a common feature of aging. Loss of bone starts in women at the time of the menopause and in men at about age 55 and leads to an increase in fracture rates in both sexes. Individual fracture risk is inversely related to bone density, which in turn is determined by the density achieved at maturity (peak bone density) and the subsequent rate of bone loss. At issue is whether either or both of these variables is related to calcium intake. The calcium requirement of adults may be defined as the mean calcium intake needed to preserve calcium balance, i.e., to meet the significant obligatory losses of calcium through the gastrointestinal tract, kidneys, and skin. The calcium allowance is the higher intake recommended for a population to allow for individual variation in the requirement. The mean requirement defined in this way, calculated from balance studies, is about 20 mmol (800 mg) a day on Western diets, implying an allowance of 25 mmol (1000 mg) or more. Corresponding requirements and allowances have been calculated for

  9. Integrated Vehicle Ground Vibration Testing of Manned Spacecraft: Historical Precedent

    NASA Technical Reports Server (NTRS)

    Lemke, Paul R.; Tuma, Margaret L.; Askins, Bruce R.

    2008-01-01

    For the first time in nearly 30 years, NASA is developing a new manned space flight launch system. The Ares I will carry crew and cargo to not only the International Space Station, but onward for the future exploration of the Moon and Mars. The Ares I control system and structural designs use complex computer models for their development. An Integrated Vehicle Ground Vibration Test (IVGVT) will validate the efficacy of these computer models. The IVGVT will reduce the technical risk of unexpected conditions that could place the vehicle or crew in jeopardy. The Ares Project Office's Flight and Integrated Test Office commissioned a study to determine how historical programs, such as Saturn and Space Shuttle, validated the structural dynamics of an integrated flight vehicle. The study methodology was to examine the historical record and seek out members of the engineering community who recall the development of historic manned launch vehicles. These records and interviews provided insight into the best practices and lessons learned from these historic development programs. The information that was gathered allowed the creation of timelines of the historic development programs. The timelines trace the programs from the development of test articles through test preparation, test operations, and test data reduction efforts. These timelines also demonstrate how the historical tests fit within their overall vehicle development programs. Finally, the study was able to quantify approximate staffing levels during historic development programs. Using this study, the Flight and Integrated Test Office was able to evaluate the Ares I Integrated Vehicle Ground Vibration Test schedule and workforce budgets in light of the historical precedents to determine if the test had schedule or cost risks associated with it.

  10. Increased cerebral oxygenation precedes generalized tonic clonic seizures.

    PubMed

    Moseley, Brian D; Britton, Jeffrey W; So, Elson

    2014-11-01

    Based on previous fMRI and SPECT studies, it has been suggested seizures may be preceded by increased cerebral blood flow. Recently, we demonstrated transcutaneous regional cerebral oxygen saturation (rSO2) sensors are feasible for use in patients undergoing video EEG monitoring. We reanalyzed our data to determine if seizures were consistently marked by increased cerebral oxygenation. Patients with histories of generalized tonic clonic seizures (GTCS) were recruited into our study. All subjects were evaluated with continuous 30-channel scalp EEG and 2 rSO2 sensors placed on each side of the forehead. We calculated the mean rSO2 value for the 1h epochs in the non-ictal (2h prior to seizure onset) and pre-ictal (1h prior to onset) periods. Seven primary/secondarily GTCS from 5 patients were captured. The mean rSO2 value in the non-ictal period was 75.6 ± 5.7%. This increased to 76.0 ± 6% in the pre-ictal period (p=0.032). Four of the 7GTCS (57.1%) were marked by ≥ 3 sequential rSO2 values in the pre-ictal period that were ≥ 3 SDs greater than the mean non-ictal rSO2 value. Three GTCS (42.9%) were marked by sustained cerebral hyperemia for ≥ 15 consecutive readings. Our results suggest increased cerebral blood flow could be non-invasively used to predict seizure occurrence. PMID:25277885

  11. Axonal Dysfunction Precedes Motor Neuronal Death in Amyotrophic Lateral Sclerosis.

    PubMed

    Iwai, Yuta; Shibuya, Kazumoto; Misawa, Sonoko; Sekiguchi, Yukari; Watanabe, Keisuke; Amino, Hiroshi; Kuwabara, Satoshi

    2016-01-01

    Wide-spread fasciculations are a characteristic feature in amyotrophic lateral sclerosis (ALS), suggesting motor axonal hyperexcitability. Previous excitability studies have shown increased nodal persistent sodium conductances and decreased potassium currents in motor axons of ALS patients, both of the changes inducing hyperexcitability. Altered axonal excitability potentially contributes to motor neuron death in ALS, but the relationship of the extent of motor neuronal death and abnormal excitability has not been fully elucidated. We performed multiple nerve excitability measurements in the median nerve at the wrist of 140 ALS patients and analyzed the relationship of compound muscle action potential (CMAP) amplitude (index of motor neuronal loss) and excitability indices, such as strength-duration time constant, threshold electrotonus, recovery cycle and current-threshold relationships. Compared to age-matched normal controls (n = 44), ALS patients (n = 140) had longer strength-duration time constant (SDTC: a measure of nodal persistent sodium current; p < 0.05), greater threshold changes in depolarizing threshold electrotonus (p < 0.05) and depolarizing current threshold relationship (i.e. less accommodation; (p < 0.05), greater superexcitability (a measure of fast potassium current; p < 0.05) and reduced late subexcitability (a measure of slow potassium current; p < 0.05), suggesting increased persistent sodium currents and decreased potassium currents. The reduced potassium currents were found even in the patient subgroups with normal CMAP (> 5mV). Regression analyses showed that SDTC (R = -0.22) and depolarizing threshold electrotonus (R = -0.22) increased with CMAP decline. These findings suggest that motor nerve hyperexcitability occurs in the early stage of the disease, and precedes motor neuronal loss in ALS. Modulation of altered ion channel function could be a treatment option for ALS. PMID:27383069

  12. Axonal Dysfunction Precedes Motor Neuronal Death in Amyotrophic Lateral Sclerosis

    PubMed Central

    Iwai, Yuta; Shibuya, Kazumoto; Misawa, Sonoko; Sekiguchi, Yukari; Watanabe, Keisuke; Amino, Hiroshi; Kuwabara, Satoshi

    2016-01-01

    Wide-spread fasciculations are a characteristic feature in amyotrophic lateral sclerosis (ALS), suggesting motor axonal hyperexcitability. Previous excitability studies have shown increased nodal persistent sodium conductances and decreased potassium currents in motor axons of ALS patients, both of the changes inducing hyperexcitability. Altered axonal excitability potentially contributes to motor neuron death in ALS, but the relationship of the extent of motor neuronal death and abnormal excitability has not been fully elucidated. We performed multiple nerve excitability measurements in the median nerve at the wrist of 140 ALS patients and analyzed the relationship of compound muscle action potential (CMAP) amplitude (index of motor neuronal loss) and excitability indices, such as strength-duration time constant, threshold electrotonus, recovery cycle and current-threshold relationships. Compared to age-matched normal controls (n = 44), ALS patients (n = 140) had longer strength-duration time constant (SDTC: a measure of nodal persistent sodium current; p < 0.05), greater threshold changes in depolarizing threshold electrotonus (p < 0.05) and depolarizing current threshold relationship (i.e. less accommodation; (p < 0.05), greater superexcitability (a measure of fast potassium current; p < 0.05) and reduced late subexcitability (a measure of slow potassium current; p < 0.05), suggesting increased persistent sodium currents and decreased potassium currents. The reduced potassium currents were found even in the patient subgroups with normal CMAP (> 5mV). Regression analyses showed that SDTC (R = -0.22) and depolarizing threshold electrotonus (R = -0.22) increased with CMAP decline. These findings suggest that motor nerve hyperexcitability occurs in the early stage of the disease, and precedes motor neuronal loss in ALS. Modulation of altered ion channel function could be a treatment option for ALS. PMID:27383069

  13. [Calcium and health].

    PubMed

    Ortega Anta, Rosa M; Jiménez Ortega, Ana I; López-Sobaler, Ana M

    2015-04-07

    An adequate intake of calcium is only not limited to avoid the risk of osteoporosis and its benefits in longterm bone health, but also it has been linked to protection against various major diseases, such as hypertension, cancer, kidney stones, insulin resistance, diabetes... and several investigations suggest its importance in preventing and controlling obesity. Studies conducted in Spanish representative samples show that a high percentage of adults and children (> 75%) don't achieve the recommended intake of calcium. Moreover, are growing trends among the population suggesting that calcium intake and dairy consumption (main food source of the mineral) are high, and even excessive, in many individuals. This misconception results in that the calcium intake is increasingly far from the recommended one. The maximum tolerable intake of the mineral is fixed at 2.500 mg/day, but this intake is unusual, and it's more disturbing and frequent, to find intakes below the recommended calcium intakes (1.000 and 1.200 mg/day in adults, men and women, respectively). Data from different studies highlight the risk of an inadequate calcium intake and the damages that may affect the health in a long term. It is not about transmitting indiscriminate guidelines in order to increase the intake of calcium / dairy, but the recommended intakes must be met to achieve both the nutritional and health benefits. Also activities for demystification of misconceptions are need, increasingly frequent, that may impair health population.

  14. Cytosolic Calcium Measurements in Renal Epithelial Cells by Flow Cytometry

    PubMed Central

    Lee, Wing-Kee; Dittmar, Thomas

    2014-01-01

    A variety of cellular processes, both physiological and pathophysiological, require or are governed by calcium, including exocytosis, mitochondrial function, cell death, cell metabolism and cell migration to name but a few. Cytosolic calcium is normally maintained at low nanomolar concentrations; rather it is found in high micromolar to millimolar concentrations in the endoplasmic reticulum, mitochondrial matrix and the extracellular compartment. Upon stimulation, a transient increase in cytosolic calcium serves to signal downstream events. Detecting changes in cytosolic calcium is normally performed using a live cell imaging set up with calcium binding dyes that exhibit either an increase in fluorescence intensity or a shift in the emission wavelength upon calcium binding. However, a live cell imaging set up is not freely accessible to all researchers. Alternative detection methods have been optimized for immunological cells with flow cytometry and for non-immunological adherent cells with a fluorescence microplate reader. Here, we describe an optimized, simple method for detecting changes in epithelial cells with flow cytometry using a single wavelength calcium binding dye. Adherent renal proximal tubule epithelial cells, which are normally difficult to load with dyes, were loaded with a fluorescent cell permeable calcium binding dye in the presence of probenecid, brought into suspension and calcium signals were monitored before and after addition of thapsigargin, tunicamycin and ionomycin. PMID:25407650

  15. Subcellular localization of calcium deposits during zebrafish (Danio rerio) oogenesis.

    PubMed

    Golpour, Amin; Pšenička, Martin; Niksirat, Hamid

    2016-01-01

    Calcium plays prominent roles in regulating a broad range of physiological events in reproduction. The aim of this study was to describe the subcellular distribution of calcium deposits during stages of oogenesis in zebrafish using a combined oxalate-pyroantimonate technique. The oocyte development of zebrafish was categorized into four stages: primary growth, cortical-alveolus, vitellogenic, and maturation, based on morphological criteria. Calcium deposits in the primary growth stage were detected in the cytoplasm, mitochondria, nucleus, and follicular cells. At the cortical-alveolus stage, calcium particles were transported from follicular cells and deposited in the cortical alveoli. In the vitellogenic stage, some cortical alveoli were compacted and transformed from flocculent electron-lucent to electron-dense objects with the progression of the stage. Calcium deposits were transformed from larger to smaller particles, coinciding with compaction of cortical alveoli. In the maturation stage, calcium deposits in all oocyte compartments decreased, with the exception of those in mitochondria. The proportion of area covered by calcium deposits in the mitochondria and cortical alveoli of oocytes at different stages of development was significantly different (p<0.05). The extent of calcium deposits in the cortical alveoli of mature oocytes was substantially lower than in earlier stages. Basic information about calcium distribution during zebrafish oogenesis may contribute to better understanding of its role in oogenesis.

  16. CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING ON LEFT, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING ON LEFT, CALCIUM CHLORIDE STORAGE BUILDING ON RIGHT OF CENTER WITH TOP OF SA (SODA ASH) BUILDING IN RIGHT BACKGROUND. - Solvay Process Company, Calcium Chloride Plant, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

  17. 21 CFR 184.1191 - Calcium carbonate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... soda process”; (2) By precipitation of calcium carbonate from calcium hydroxide in the “Carbonation process”; or (3) By precipitation of calcium carbonate from calcium chloride in the “Calcium...

  18. 21 CFR 184.1191 - Calcium carbonate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... soda process”; (2) By precipitation of calcium carbonate from calcium hydroxide in the “Carbonation process”; or (3) By precipitation of calcium carbonate from calcium chloride in the “Calcium...

  19. 21 CFR 184.1191 - Calcium carbonate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... soda process”; (2) By precipitation of calcium carbonate from calcium hydroxide in the “Carbonation process”; or (3) By precipitation of calcium carbonate from calcium chloride in the “Calcium...

  20. 21 CFR 184.1191 - Calcium carbonate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... soda process”; (2) By precipitation of calcium carbonate from calcium hydroxide in the “Carbonation process”; or (3) By precipitation of calcium carbonate from calcium chloride in the “Calcium...

  1. Rising catch variability preceded historical fisheries collapses in Alaska.

    PubMed

    Litzow, Michael A; Mueter, Franz J; Urban, J Daniel

    2013-09-01

    Statistical indicators such as rising variance and rising skewness in key system parameters may provide early warning of "regime shifts" in communities and populations. However, the utility of these indicators has rarely been tested in the large, complex ecosystems that are of most interest to managers. Crustacean fisheries in the Gulf of Alaska and Bering Sea experienced a series of collapses beginning in the 1970s, and we used spatially resolved catch data from these fisheries to test the predictions that increasing variability and skewness would precede stock collapse. Our data set consisted of catch data from 14 fisheries (12 collapsing and two non-collapsing), spanning 278 cumulative years. Our sampling unit for analysis was the Alaska Department of Fish and Game statistical reporting area (mean n for individual fisheries = 42 areas, range 7-81). We found that spatial variability in catches increased prior to stock collapse: a random-effects model estimating trend in variability across all 12 collapsing fisheries showed strong evidence of increasing variability prior to collapse. Individual trends in variability were statistically significant for only four of the 12 collapsing fisheries, suggesting that rising variability might be most effective as an indicator when information from multiple populations is available. Analyzing data across multiple fisheries allowed us to detect increasing variability 1-4 years prior to collapse, and trends in variability were significantly different for collapsing and non-collapsing fisheries. In spite of theoretical expectations, we found no evidence of pre-collapse increases in catch skewness. Further, while models generally predict that rising variability should be a transient phenomenon around collapse points, increased variability was a persistent feature of collapsed fisheries in our study. We conclude that this result is more consistent with fishing effects as the cause of increased catch variability, rather than the

  2. Stoichiometry of Calcium Medicines

    ERIC Educational Resources Information Center

    Pinto, Gabriel

    2005-01-01

    The topic of calcium supplement and its effects on human lives is presented in the way of questions to the students. It enables the students to realize the relevance of chemistry outside the classroom surrounding.

  3. Calcium channel blocker overdose

    MedlinePlus

    ... Goldschlager N. Cardiovascular toxicology. In: Shannon MW, Borron SW, Burns MJ, eds. Haddad and Winchester's Clinical Management ... SD. Calcium channel antagonists. In: Shannon MW, Borron SW, Burns MJ, eds. Haddad and Winchester's Clinical Management ...

  4. Calcium blood test

    MedlinePlus

    ... failure Low blood level of albumin Liver disease Magnesium deficiency Pancreatitis Vitamin D deficiency ... PA: Elsevier; 2013:chap 66. Leone KA. Calcium, magnesium, and phosphorus. In: Adams JG, ed. Emergency Medicine: ...

  5. Calcium Channel Signaling Complexes with Receptors and Channels.

    PubMed

    Zamponi, Gerald W

    2015-01-01

    Voltage-gated calcium channels are not only mediators of cell signalling events, but also are recipients of signalling inputs from G protein coupled receptors (GPCRs) and their associated second messenger pathways. The coupling of GPCRs to calcium channels is optimized through the formation of receptor-channel complexes. In addition, this provides a mechanism for receptorchannel co-trafficking to and from the plasma membrane. On the other hand, voltage-gated calcium channel activity affects other types of ion channels such as voltage-and calcium-activated potassium channels. Coupling efficiency between these two families of channels is also enhanced through the formation of channel-channel complexes. This review provides a concise overview of the current state of knowledge on the physical interactions between voltage-gated calcium channels and members of the GPCR family, and with other types of ion channels.

  6. Nondisjunctional segregations in Drosophila female meiosis I are preceded by homolog malorientation at metaphase arrest.

    PubMed

    Gillies, Shane C; Lane, Fiona M; Paik, Wonbeom; Pyrtel, Khateriaa; Wallace, Nneka T; Gilliland, William D

    2013-02-01

    The model of Drosophila female meiosis I was recently revised by the discovery that chromosome congression precedes metaphase I arrest. Use of the prior framework to interpret data from meiotic mutants led to the conclusion that chromosome segregation errors (nondisjunction, NDJ) occurred when nonexchange chromosomes moved out on the spindle in a maloriented configuration and became trapped there at metaphase arrest. The discovery that congression returns nonexchange chromosomes to the metaphase plate invalidates this interpretation and raises the question of what events actually do lead to NDJ. To address this, we have assayed an allelic series of ald (mps1) meiotic mutants that complete congression at wild-type rates, but have widely varying NDJ rates in an otherwise isogenic background, as well as a nod mutant background that primarily undergoes loss of chromosome 4. Using genetic assays to measure NDJ rates, and FISH assays to measure chromosome malorientation rates in metaphase-arrested oocytes, shows that these two rates are highly correlated across ald mutants, suggesting that malorientation during congression commits these chromosomes to eventually nondisjoin. Likewise, the rate of chromosome loss observed in nod is similar to the rate at which these chromosomes fail to associate with the main chromosome mass. Together these results provide a proximal mechanism for how these meiotic mutants cause NDJ and chromosome loss and improve our understanding of how prometaphase chromosome congression relates to anaphase chromosome segregation. PMID:23222652

  7. Nondisjunctional Segregations in Drosophila Female Meiosis I Are Preceded by Homolog Malorientation at Metaphase Arrest

    PubMed Central

    Gillies, Shane C.; Lane, Fiona M.; Paik, Wonbeom; Pyrtel, Khateriaa; Wallace, Nneka T.; Gilliland, William D.

    2013-01-01

    The model of Drosophila female meiosis I was recently revised by the discovery that chromosome congression precedes metaphase I arrest. Use of the prior framework to interpret data from meiotic mutants led to the conclusion that chromosome segregation errors (nondisjunction, NDJ) occurred when nonexchange chromosomes moved out on the spindle in a maloriented configuration and became trapped there at metaphase arrest. The discovery that congression returns nonexchange chromosomes to the metaphase plate invalidates this interpretation and raises the question of what events actually do lead to NDJ. To address this, we have assayed an allelic series of ald (mps1) meiotic mutants that complete congression at wild-type rates, but have widely varying NDJ rates in an otherwise isogenic background, as well as a nod mutant background that primarily undergoes loss of chromosome 4. Using genetic assays to measure NDJ rates, and FISH assays to measure chromosome malorientation rates in metaphase-arrested oocytes, shows that these two rates are highly correlated across ald mutants, suggesting that malorientation during congression commits these chromosomes to eventually nondisjoin. Likewise, the rate of chromosome loss observed in nod is similar to the rate at which these chromosomes fail to associate with the main chromosome mass. Together these results provide a proximal mechanism for how these meiotic mutants cause NDJ and chromosome loss and improve our understanding of how prometaphase chromosome congression relates to anaphase chromosome segregation. PMID:23222652

  8. The influence of preceding dive cycles on the foraging decisions of Antarctic fur seals

    PubMed Central

    Iwata, T.; Sakamoto, K. Q.; Edwards, E. W. J.; Staniland, I. J.; Trathan, P. N.; Goto, Y.; Sato, K.; Naito, Y.; Takahashi, A.

    2015-01-01

    The foraging strategy of many animals is thought to be determined by their past experiences. However, few empirical studies have investigated whether this is true in diving animals. We recorded three-dimensional movements and mouth-opening events from three Antarctic fur seals during their foraging trips to examine how they adapt their behaviour based on past experience—continuing to search for prey in the same area or moving to search in a different place. Each dive cycle was divided into a transit phase and a feeding phase. The linear horizontal distance travelled after feeding phases in each dive was affected by the mouth-opening rate during the previous 244 s, which typically covered two to three dive cycles. The linear distance travelled tended to be shorter when the mouth-opening rate in the previous 244 s was higher, i.e. seals tended to stay in the same areas with high prey-encounter rates. These results indicate that Antarctic fur seals follow decision-making strategies based on the past foraging experience over time periods longer than the immediately preceding dive. PMID:26156132

  9. DNA damage precedes apoptosis during the regression of the interdigital tissue in vertebrate embryos

    PubMed Central

    Montero, Juan A.; Sanchez-Fernandez, Cristina; Lorda-Diez, Carlos I.; Garcia-Porrero, Juan A.; Hurle, Juan M.

    2016-01-01

    DNA damage independent of caspase activation accompanies programmed cell death in different vertebrate embryonic organs. We analyzed the significance of DNA damage during the regression of the interdigital tissue, which sculpts the digits in the embryonic limb. Interdigit remodeling involves oxidative stress, massive apoptosis and cell senescence. Phosphorylation of H2AX mediated by ATM precedes caspase dependent apoptosis and cell senescence during interdigit regression. The association of γH2AX with other downstream DNA repair factors, including MDC1, Rad50 and 53BP1 suggests a defensive response of cells against DNA damage. The relative distribution of cells γH2AX-only positive, TUNEL-only positive, and cells double positive for both markers is consistent with a sequence of degenerative events starting by damage of the DNA. In support of this interpretation, the relative number of γH2AX-only cells increases after caspase inhibition while the relative number of TUNEL-only cells increases after inhibition of ATM. Furthermore, cultured interdigits survived and maintained intense chondrogenic potential, even at advanced stages of degeneration, discarding a previous commitment to die. Our findings support a new biological paradigm considering embryonic cell death secondary to genotoxic stimuli, challenging the idea that considers physiological cell death a cell suicide regulated by an internal death clock that pre-programmes degeneration. PMID:27752097

  10. Multiple late Triassic carbon cycle perturbations preceding intensified volcanic activity in the Central Atlantic Magmatic Province

    NASA Astrophysics Data System (ADS)

    Ruhl, Micha; Kürschner, Wolfram M.

    2010-05-01

    The end-Triassic mass extinction (~201.5 Ma), marked by terrestrial ecosystem changes and a 50% loss in marine biodiversity, coincides with a major disruption of the global carbon cycle. These events closely coincide with the onset of Central Atlantic Magmatic Province emplacement (Deenen et al., 2010) and the subsequent release of isotopically depleted carbon as gaseous CO2 and from the methane hydrate reservoir. Here we show that the end-Triassic C-cycle perturbation is preceded by two successive 2-3‰ Rhaetian negative excursions in marine and continental δ13CTOC records from the western Tethys and north-west European sections. A coinciding, albeit slightly smaller, negative excursion in a δ13C leaf-record (Lepidopteris ottonis) further suggests successive 13C depletion of the late Triassic global atmosphere. Extensive dyke and sill systems that allowed major flood basalt emplacement in the Central Atlantic Magmatic Province, already intruded sedimentary basins over large parts of Pangea during the late Triassic. Subsurface thermal metamorphism of organic rich strata potentially led to oxidation of organic carbon and the transfer of isotopically depleted carbon to the exogenic carbon pool. In this way causing changes in the global C-cycle already before the onset of major volcanic activity.

  11. Strong and Anomalous Thermal Expansion Precedes the Thermosalient Effect in Dynamic Molecular Crystals.

    PubMed

    Panda, Manas K; Centore, Roberto; Causà, Mauro; Tuzi, Angela; Borbone, Fabio; Naumov, Panče

    2016-01-01

    The ability of thermosalient solids, organic analogues of inorganic martensites, to move by rapid mechanical reconfiguration or ballistic event remains visually appealing and potentially useful, yet mechanistically elusive phenomenon. Here, with a material that undergoes both thermosalient and non-thermosalient phase transitions, we demonstrate that the thermosalient effect is preceded by anomalous thermal expansion of the unit cell. The crystal explosion occurs as sudden release of the latent strain accumulated during the anisotropic, exceedingly strong expansion of the unit cell with αa = 225.9 × 10(-6) K(-1), αb = 238.8 × 10(-6) K(-1) and αc = -290.0 × 10(-6) K(-1), the latter being the largest negative thermal expansivity observed for an organic compound thus far. The results point out to the occurence of the thermosalient effect in phase transitions as means to identify new molecular materials with strong positive and/or negative thermal expansion which prior to this work could only be discovered serendipitously. PMID:27403616

  12. The influence of preceding dive cycles on the foraging decisions of Antarctic fur seals.

    PubMed

    Iwata, T; Sakamoto, K Q; Edwards, E W J; Staniland, I J; Trathan, P N; Goto, Y; Sato, K; Naito, Y; Takahashi, A

    2015-07-01

    The foraging strategy of many animals is thought to be determined by their past experiences. However, few empirical studies have investigated whether this is true in diving animals. We recorded three-dimensional movements and mouth-opening events from three Antarctic fur seals during their foraging trips to examine how they adapt their behaviour based on past experience--continuing to search for prey in the same area or moving to search in a different place. Each dive cycle was divided into a transit phase and a feeding phase. The linear horizontal distance travelled after feeding phases in each dive was affected by the mouth-opening rate during the previous 244 s, which typically covered two to three dive cycles. The linear distance travelled tended to be shorter when the mouth-opening rate in the previous 244 s was higher, i.e. seals tended to stay in the same areas with high prey-encounter rates. These results indicate that Antarctic fur seals follow decision-making strategies based on the past foraging experience over time periods longer than the immediately preceding dive.

  13. Strong and Anomalous Thermal Expansion Precedes the Thermosalient Effect in Dynamic Molecular Crystals

    NASA Astrophysics Data System (ADS)

    Panda, Manas K.; Centore, Roberto; Causà, Mauro; Tuzi, Angela; Borbone, Fabio; Naumov, Panče

    2016-07-01

    The ability of thermosalient solids, organic analogues of inorganic martensites, to move by rapid mechanical reconfiguration or ballistic event remains visually appealing and potentially useful, yet mechanistically elusive phenomenon. Here, with a material that undergoes both thermosalient and non-thermosalient phase transitions, we demonstrate that the thermosalient effect is preceded by anomalous thermal expansion of the unit cell. The crystal explosion occurs as sudden release of the latent strain accumulated during the anisotropic, exceedingly strong expansion of the unit cell with αa = 225.9 × 10‑6 K‑1, αb = 238.8 × 10‑6 K‑1 and αc = ‑290.0 × 10‑6 K‑1, the latter being the largest negative thermal expansivity observed for an organic compound thus far. The results point out to the occurence of the thermosalient effect in phase transitions as means to identify new molecular materials with strong positive and/or negative thermal expansion which prior to this work could only be discovered serendipitously.

  14. Remodeling of Glucose Metabolism Precedes Pressure Overload -Induced Left Ventricular Hypertrophy: Review of a Hypothesis

    PubMed Central

    Kundu, Bijoy K.; Zhong, Min; Sen, Shiraj; Davogustto, Giovanni; Keller, Susanna R.; Taegtmeyer, Heinrich

    2015-01-01

    When subjected to pressure overload, the ventricular myocardium shifts from fatty acids to glucose as its main source for energy provision and frequently increases its mass. Here, we review the evidence in support of the concept that metabolic remodeling, measured as increased myocardial glucose uptake using dynamic positron emission tomography (PET) with the glucose analogue 2-deoxy-2-[18F]-fluoro-D-glucose (FDG), precedes the onset of left ventricular hypertrophy (LVH) and heart failure. Consistent with this, early intervention with propranolol, which attenuates glucose uptake, prevents the maladaptive metabolic response and preserves cardiac function in vivo. We also review ex vivo studies suggesting a link between dysregulated myocardial glucose metabolism, intracellular accumulation of glucose 6-phosphate (G6P) and contractile dysfunction of the heart. G6P levels correlate with activation of mTOR (mechanistic target of rapamycin) and endoplasmic reticulum stress. This sequence of events could be prevented by pre-treatment with rapamycin (mTOR inhibition) or metformin (enzyme 5′-AMP-activated protein kinase activation ). In conclusion, we propose that metabolic imaging with FDG PET may provide a novel approach to guide the treatment of patients with hypertension-induced LVH. PMID:25791172

  15. Strong and Anomalous Thermal Expansion Precedes the Thermosalient Effect in Dynamic Molecular Crystals

    PubMed Central

    Panda, Manas K.; Centore, Roberto; Causà, Mauro; Tuzi, Angela; Borbone, Fabio; Naumov, Panče

    2016-01-01

    The ability of thermosalient solids, organic analogues of inorganic martensites, to move by rapid mechanical reconfiguration or ballistic event remains visually appealing and potentially useful, yet mechanistically elusive phenomenon. Here, with a material that undergoes both thermosalient and non-thermosalient phase transitions, we demonstrate that the thermosalient effect is preceded by anomalous thermal expansion of the unit cell. The crystal explosion occurs as sudden release of the latent strain accumulated during the anisotropic, exceedingly strong expansion of the unit cell with αa = 225.9 × 10−6 K−1, αb = 238.8 × 10−6 K−1 and αc = −290.0 × 10−6 K−1, the latter being the largest negative thermal expansivity observed for an organic compound thus far. The results point out to the occurence of the thermosalient effect in phase transitions as means to identify new molecular materials with strong positive and/or negative thermal expansion which prior to this work could only be discovered serendipitously. PMID:27403616

  16. Macrophages engulf endothelial cell membrane particles preceding pupillary membrane capillary regression

    PubMed Central

    Poché, Ross A.; Hsu, Chih-Wei; McElwee, Melissa L.; Burns, Alan R.; Dickinson, Mary E.

    2015-01-01

    Programmed capillary regression and remodeling are essential developmental processes. However, the cellular and molecular mechanisms that regulate vessel regression are only beginning to be understood. Here, using in vivo, dynamic, confocal imaging of mouse transgenic reporters as well as static confocal and electron microscopy, we studied the embryonic development and postnatal regression of the transient mouse pupillary membrane (PM) vasculature. This approach allowed us to directly observe the precise temporal sequence of cellular events preceding and during the elimination of the PM from the mouse eye. Imaging of Tcf/Lef-H2B::GFP Wnt-reporter mice uncovered that, unlike the hyaloid vasculature of the posterior eye, a PM endothelial cell (EC) Wnt/β-catenin response is unlikely to be part of the regression mechanism. Live imaging of EC and macrophage dynamics revealed highly active Csf1r-GFP+ macrophages making direct contact with the Flk1-myr::mCherry+ vessel surface and with membrane protrusions or filopodia extending from the ECs. Flk1-myr::mCherry+ EC membrane particles were observed on and around ECs as well as within macrophages. Electron microscopy studies confirmed that they were in phagosomes within macrophages, indicating that the macrophages engulfed the membrane particles. Interestingly, EC plasma membrane uptake by PM macrophages did not correlate with apoptosis and was found shortly after vessel formation at mid-gestation stages in the embryo; long before vessel regression begins during postnatal development. Additionally, genetic ablation of macrophages showed that EC membrane particles were still shed in the absence of macrophages suggesting that macrophages do not induce the formation or release of EC microparticles. These studies have uncovered a novel event during programmed capillary regression in which resident macrophages scavenge endothelial cell microparticles released from the PM vessels. This finding suggests that there may be an

  17. The number and spatial distribution of IP3 receptors underlying calcium puffs in Xenopus oocytes.

    PubMed

    Shuai, Jianwei; Rose, Heather J; Parker, Ian

    2006-12-01

    Calcium puffs are local Ca(2+) release events that arise from a cluster of inositol 1,4,5-trisphosphate receptor channels (IP(3)Rs) and serve as a basic "building block" from which global Ca(2+) waves are generated. Important questions remain as to the number of IP(3)Rs that open during a puff, their spatial distribution within a cluster, and how much Ca(2+) current flows through each channel. The recent discovery of "trigger" events-small Ca(2+) signals that immediately precede puffs and are interpreted to arise through opening of single IP(3)R channels-now provides a useful yardstick by which to calibrate the Ca(2+) flux underlying puffs. Here, we describe a deterministic numerical model to simulate puffs and trigger events. Based on confocal linescan imaging in Xenopus oocytes, we simulated Ca(2+) release in two sequential stages; representing the trigger by the opening of a single IP(3)R in the center of a cluster for 12 ms, followed by the concerted opening of some number of IP(3)Rs for 19 ms, representing the rising phase of the puff. The diffusion of Ca(2+) and Ca(2+)-bound indicator dye were modeled in a three-dimensional cytosolic volume in the presence of immobile and mobile Ca(2+) buffers, and were used to predict the observed fluorescence signal after blurring by the microscope point-spread function. Optimal correspondence with experimental measurements of puff spatial width and puff/trigger amplitude ratio was obtained assuming that puffs arise from the synchronous opening of 25-35 IP(3)Rs, each carrying a Ca(2+) current of approximately 0.4 pA, with the channels distributed through a cluster 300-800 nm in diameter. PMID:16980372

  18. 26 CFR 1.665(e)-1A - Preceding taxable year.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 8 2014-04-01 2014-04-01 false Preceding taxable year. 1.665(e)-1A Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Treatment of Excess Distributions of Trusts Applicable to Taxable Years Beginning on Or After January 1, 1969 § 1.665(e)-1A Preceding taxable year. (a) Definition—(1)...

  19. 26 CFR 1.665(e)-1A - Preceding taxable year.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 8 2012-04-01 2012-04-01 false Preceding taxable year. 1.665(e)-1A Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Treatment of Excess Distributions of Trusts Applicable to Taxable Years Beginning on Or After January 1, 1969 § 1.665(e)-1A Preceding taxable year. (a) Definition—(1)...

  20. 26 CFR 1.665(e)-1A - Preceding taxable year.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 8 2011-04-01 2011-04-01 false Preceding taxable year. 1.665(e)-1A Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Treatment of Excess Distributions of Trusts Applicable to Taxable Years Beginning on Or After January 1, 1969 § 1.665(e)-1A Preceding taxable year. (a) Definition—(1)...

  1. [Voltage gated calcium channels: structure, characteristics and terminology].

    PubMed

    Veizerová, L; Svetlík, J; Kettmann, V

    2007-07-01

    Voltage-gated Ca2+ channels are the major pathway of Ca2+ entry into the cells. Their activity is essential to couple electrical signals from the cell surface to physiological events in cells. Several pharmacologically, structurally and kinetically distinct calcium channel types have been identified at the electrophysiological and molecular levels. This review aims to describe the functional, structural and pharmacological properties of voltage-gated calcium channels.

  2. Analysis of Intracellular Calcium Signaling in Human Embryonic Stem Cells.

    PubMed

    Péntek, Adrienn; Pászty, Katalin; Apáti, Ágota

    2016-01-01

    Measurement of changes in intracellular calcium concentration is one of the most common and useful tools for studying signal transduction pathways or cellular responses in basic research and drug screening purposes as well. Increasing number of such applications using human pluripotent stem cells and their derivatives requires development of calcium signal measurements for this special cell type. Here we describe a modified protocol for analysis of calcium signaling events in human embryonic stem cells, which can be used for other pluripotent cell types (such as iPSC) or their differentiated offspring as well.

  3. Inhibition of gravitropism in oat coleoptiles by calcium chelation

    NASA Technical Reports Server (NTRS)

    Roux, S. J.

    1984-01-01

    Some cellular event necessary for gravitropism is inhibited by EGTA without interferring with the overall growth. Calcium relieves this inhibition and demonstrates both that inhibition is reversible and was probably due to a reduction in the ability to free calcium required for one or more at the transduction steps of gravitropism. At the near neutral pH used, EGTA is charged and would not be expected to readily cross the membrane. One of its primary effects, then, is probably the bringing of free calcium in the apoplastic space exterior to the cell membranes.

  4. Etiquette and Protocol: A Guide for Campus Events.

    ERIC Educational Resources Information Center

    Harris, April L.

    Intended for special events planners on college campuses, this book offers advice on matters of etiquette and protocol for campus events. Chapters cover the following topics: (1) invitations (e.g., the precedence of extending invitations, invitation components, formal invitations, types of invitations); (2) forms of address (with examples of…

  5. Behaviour patterns preceding a railway suicide: Explorative study of German Federal Police officers' experiences

    PubMed Central

    2011-01-01

    Background Constant high-level numbers of railway suicides indicate that prevention strategies against railway suicides are urgently needed. The main question of the present study was whether pre-crash railway suicide behaviour can be identified, using German Federal Police officers experience with suicidal events in railway related environments. Methods To collect information on pre-crash railway suicide behaviour, a questionnaire was used and made available on the German Federal Police intranet. A total of 202 subjects (mean age: 41 years, sex: 84.9% male) were included in the analysis. Multivariate logistic regression analyses were performed to predict the prevention of suicide (first model) or demand for counselling (second model) as outcomes. Sex, age, years of service, number of experienced suicides, suicides personally observed, information on suicides obtained from witnesses and finally either counselling/debriefing (first model) or whether officers had prevented a suicide (second model) were used as predictors. Results A considerable proportion of police officers reported behavioural patterns preceding a suicide. Half of them observed the dropping or leaving behind of personal belongings or the avoidance of eye contact, more than a third erratic gesture, mimic or movement. Erratic communication patterns and general confusion were each reported by about one quarter. One fifth indicated the influence of alcohol. Less frequently observed behaviour was aimlessly wandering (14.3%) and out of the ordinary clothing (4%). About one third of all railway suicide victims committed suicide in stations. Of those, 70% had chosen an eminent spot. The multivariate logistic regression model using prevented suicides as the outcome identified the number of suicides experienced, counselling/debriefing and having personally observed a suicide as variables with significant impact. The model using counselling/debriefing as the outcome identified age and having prevented a

  6. Calcium transport, thiol status, and hepatotoxicity following N-nitrosodimethylamine exposure in mice

    SciTech Connect

    Reitman, F.A.; Berger, M.L.; Minnema, D.J.; Shertzer, H.G.

    1988-01-01

    The hepatotoxicant N-nitrosodimethylamine (NDMA) is presumed to exert toxicity through reactive metabolites. NDMA is similar in this respect to numerous other hepatotoxicants, for which hepatotoxicity is also associated with a rapid depletion of soluble and/or protein thiols, and an inhibition of calcium transport systems. The authors examined the hypothesis that hepatotoxicity for NDMA is preceded by thiol depletion and/or inhibition of calcium transport in isolated liver subcellular fractions. Centrizonal liver necrosis in mice was evident at 24 but not at 12 h subsequent to intraperitoneal administration of 40 mg NDMA/kg. Hepatotoxicity was not preceded by depletion of liver protein-free sulfhydryls, nor by protein sulfhydryl depletion in liver whole homogenate, microsomal, or plasma membrane fractions. NDMA-mediated toxicity was also not preceded by inhibition of calcium uptake capability by microsomal, mitochondrial, or plasma membrane fractions. In contrast, carbon tetrachloride produced the expected rapid decrease in microsomal calcium uptake capability, followed by a centrizonal necrosis that was maximal at about 24 h. These studies suggest that the mechanism of NDMA hepatotoxicity may differ from that of a number of other hepatotoxicants (e.g., carbon tetrachloride, acetaminophen, bromobenzene) for which toxicity is also mediated through reactive metabolites.

  7. [Microbial geochemical calcium cycle].

    PubMed

    Zavarzin, G A

    2002-01-01

    The participation of microorganisms in the geochemical calcium cycle is the most important factor maintaining neutral conditions on the Earth. This cycle has profound influence on the fate of inorganic carbon, and, thereby, on the removal of CO2 from the atmosphere. The major part of calcium deposits was formed in the Precambrian, when prokaryotic biosphere predominated. After that, calcium recycling based on biogenic deposition by skeletal organisms became the main process. Among prokaryotes, only a few representatives, e.g., cyanobacteria, exhibit a special calcium function. The geochemical calcium cycle is made possible by the universal features of bacteria involved in biologically mediated reactions and is determined by the activities of microbial communities. In the prokaryotic system, the calcium cycle begins with the leaching of igneous rock predominantly through the action of the community of organotrophic organisms. The release of carbon dioxide to the soil air by organotrophic aerobes leads to leaching with carbonic acid and soda salinization. Under anoxic conditions, of major importance is the organic acid production by primary anaerobes (fermentative microorganisms). Calcium carbonate is precipitated by secondary anaerobes (sulfate reducers) and to a smaller degree by methanogens. The role of the cyanobacterial community in carbonate deposition is exposed by stromatolites, which are the most common organo-sedimentary Precambrian structures. Deposition of carbonates in cyanobacterial mats as a consequence of photoassimilation of CO2 does not appear to be a significant process. It is argued that carbonates were deposited at the boundary between the "soda continent", which emerged as a result of subaerial leaching with carbonic acid, and the ocean containing Ca2+. Such ecotones provided favorable conditions for the development of the benthic cyanobacterial community, which was a precursor of stromatolites.

  8. Role of calcium in growth inhibition induced by a novel cell surface sialoglycopeptide

    NASA Technical Reports Server (NTRS)

    Betz, N. A.; Westhoff, B. A.; Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1995-01-01

    Our laboratory has purified an 18 kDa cell surface sialoglycopeptide growth inhibitor (CeReS-18) from intact bovine cerebral cortex cells. Evidence presented here demonstrates that sensitivity to CeReS-18-induced growth inhibition in BALB-c 3T3 cells is influenced by calcium, such that a decrease in the calcium concentration in the growth medium results in an increase in sensitivity to CeReS-18. Calcium did not alter CeReS-18 binding to its cell surface receptor and CeReS-18 does not bind calcium directly. Addition of calcium, but not magnesium, to CeReS-18-inhibited 3T3 cells results in reentry into the cell cycle. A greater than 3-hour exposure to increased calcium is required for escape from CeReS-18-induced growth inhibition. The calcium ionophore ionomycin could partially mimic the effect of increasing extracellular calcium, but thapsigargin was ineffective in inducing escape from growth inhibition. Increasing extracellular calcium 10-fold resulted in an approximately 7-fold increase in total cell-associated 45Ca+2, while free intracellular calcium only increased approximately 30%. However, addition of CeReS-18 did not affect total cell-associated calcium or the increase in total cell-associated calcium observed with an increase in extracellular calcium. Serum addition induced mobilization of intracellular calcium and influx across the plasma membrane in 3T3 cells, and pretreatment of 3T3 cells with CeReS-18 appeared to inhibit these calcium mobilization events. These results suggest that a calcium-sensitive step exists in the recovery from CeReS-18-induced growth inhibition. CeReS-18 may inhibit cell proliferation through a novel mechanism involving altering the intracellular calcium mobilization/regulation necessary for cell cycle progression.

  9. Gravimetric Determination of Calcium as Calcium Carbonate Hydrate.

    ERIC Educational Resources Information Center

    Henrickson, Charles H.; Robinson, Paul R.

    1979-01-01

    The gravimetric determination of calcium as calcium carbonate is described. This experiment is suitable for undergraduate quantitative analysis laboratories. It is less expensive than determination of chloride as silver chloride. (BB)

  10. Ordering of neuronal apoptosis signaling: a superoxide burst precedes mitochondrial cytochrome c release in a growth factor deprivation model

    PubMed Central

    Lieven, Christopher J.; Thurber, Katherine A.; Levin, Emily J.

    2012-01-01

    Axonal injury to retinal ganglion cells, a defined central neuron, induces a burst of intracellular superoxide anion that precedes externalization of membrane phosphatidylserine and subsequent apoptotic cell death. Dismutation of superoxide prevents the signal and delays loss of these cells, consistent with superoxide being necessary for transduction of the axotomy signal. However, phosphatidylserine externalization is a relatively late step in apoptosis, and it is possible that the superoxide burst is not an early axotomy signal but rather a result of cytochrome c release from the mitochondrial inner membrane with consequent accumulation of reduced intermediates. Other possibilities are that both superoxide generation and cytochrome c release are induced in parallel by axotomy, or that cytochrome c release potentiates the effect of the superoxide burst. To distinguish these various possibilities, serum-deprived neuronal retinal cells were assayed in vitro for superoxide elevation and release of cytochrome c from mitochondria, and the distribution of these two markers across a large number of cells used to model the temporal ordering of events. Based on this model of factor-dependent cell death, superoxide precedes, and possibly potentiates, cytochrome c release, and thus the former is likely an early signal for certain types of neuronal apoptosis in the central nervous system. PMID:22411528

  11. Ordering of neuronal apoptosis signaling: a superoxide burst precedes mitochondrial cytochrome c release in a growth factor deprivation model.

    PubMed

    Lieven, Christopher J; Thurber, Katherine A; Levin, Emily J; Levin, Leonard A

    2012-06-01

    Axonal injury to retinal ganglion cells, a defined central neuron, induces a burst of intracellular superoxide anion that precedes externalization of membrane phosphatidylserine and subsequent apoptotic cell death. Dismutation of superoxide prevents the signal and delays loss of these cells, consistent with superoxide being necessary for transduction of the axotomy signal. However, phosphatidylserine externalization is a relatively late step in apoptosis, and it is possible that the superoxide burst is not an early axotomy signal but rather a result of cytochrome c release from the mitochondrial inner membrane with consequent accumulation of reduced intermediates. Other possibilities are that both superoxide generation and cytochrome c release are induced in parallel by axotomy, or that cytochrome c release potentiates the effect of the superoxide burst. To distinguish these various possibilities, serum-deprived neuronal retinal cells were assayed in vitro for superoxide elevation and release of cytochrome c from mitochondria, and the distribution of these two markers across a large number of cells used to model the temporal ordering of events. Based on this model of factor-dependent cell death, superoxide precedes, and possibly potentiates, cytochrome c release, and thus the former is likely an early signal for certain types of neuronal apoptosis in the central nervous system. PMID:22411528

  12. Precedence-effect-induced enhancement of prepulse inhibition in socially reared but not isolation-reared rats.

    PubMed

    Du, Yi; Li, Jingyu; Wu, Xihong; Li, Liang

    2009-03-01

    Attention to a prepulse presented shortly before a startling stimulus enhances prepulse inhibition (PPI) of startle in normal people, but not in schizophrenics. Fear conditioning for the prepulse enhances PPI in socially reared, but not isolation-reared, rats. In humans, selective attention to acoustic signals against masking can be facilitated by precedence-effect-induced perceived spatial separation between the signal and the masker. This study investigated whether perceived spatial separation between a prepulse and a noise masker enhances PPI in socially reared rats and isolation-reared rats. The results show that both PPI and conditioning-induced PPI enhancement were larger in socially reared rats than in isolation-reared rats. More important, in socially reared, but not isolation-reared, rats, a further PPI enhancement was induced by precedence-effect-induced perceived separation between a prepulse and a masker only after the prepulse became fear conditioned. Thus, perceived separation facilitates normal rats' attention to a conditioned prepulse and enhances PPI. Isolation rearing impairs rats' ability to attend to ecologically significant acoustic events. PMID:19246326

  13. Effects of Dietary Calcium Restriction and Chronic Thyroparathyroidectomy on the Metabolism of [3H]25-Hydroxyvitamin D3 and the Active Transport of Calcium by Rat Intestine

    PubMed Central

    Favus, Murray J.; Walling, Marlin W.; Kimberg, Daniel V.

    1974-01-01

    Previous studies have shown that chronically thyroparathyroidectomized (TPTX) rats, fed a diet with restricted calcium but adequate phosphorus and vitamin D content, have higher levels of intestinal calcium absorption than controls. The results of recent acute experiments have suggested that parathyroid hormone (PTH) may be essential for regulating the renal conversion of 25-hydroxyvitamin D3 (25-OH-D3) to 1,25-dihydroxyvitamin D3 [1,25-(OH)2-D3] in response to dietary calcium deprivation. Since 1,25-(OH)2-D3 is the form of the vitamin thought to be active in the intestine, increases in calcium transport mediated by this metabolite would not be expected to occur in the absence of the parathyroid glands if the preceding model is correct. The present study was undertaken to examine the chronic effects of both dietary calcium restriction and the absence of PTH on the metabolism of [3H]25-OH-D3 and duodenal calcium-active transport in rats given thyroid replacement. These relatively long term studies confirm earlier observations which indicated that the adaptation of calcium absorption to a low calcium intake occurs in both sham-operated and TPTX animals. The present studies also demonstrated that despite reduced levels of 1,25-(OH)2-D3 in the plasma of chronically TPTX animals fed a low calcium diet, the accumulation of this metabolite in at least one target tissue, intestinal mucosa, is identical in both the sham-operated and TPTX groups. A reduced, but continued level of 1,25-(OH)2-D3 production, together with its selective accumulation by intestinal mucosa, probably explains the calcium adaptation which is observed inspite of the chronic absence of the parathyroid glands. PMID:4815079

  14. Autoproteolysis and Intramolecular Dissociation of Yersinia YscU Precedes Secretion of Its C-Terminal Polypeptide YscUCC

    PubMed Central

    Frost, Stefan; Ho, Oanh; Login, Frédéric H.; Weise, Christoph F.; Wolf-Watz, Hans; Wolf-Watz, Magnus

    2012-01-01

    Type III secretion system mediated secretion and translocation of Yop-effector proteins across the eukaryotic target cell membrane by pathogenic Yersinia is highly organized and is dependent on a switching event from secretion of early structural substrates to late effector substrates (Yops). Substrate switching can be mimicked in vitro by modulating the calcium levels in the growth medium. YscU that is essential for regulation of this switch undergoes autoproteolysis at a conserved N↑PTH motif, resulting in a 10 kDa C-terminal polypeptide fragment denoted YscUCC. Here we show that depletion of calcium induces intramolecular dissociation of YscUCC from YscU followed by secretion of the YscUCC polypeptide. Thus, YscUCC behaved in vivo as a Yop protein with respect to secretion properties. Further, destabilized yscU mutants displayed increased rates of dissociation of YscUCC in vitro resulting in enhanced Yop secretion in vivo at 30°C relative to the wild-type strain.These findings provide strong support to the relevance of YscUCC dissociation for Yop secretion. We propose that YscUCC orchestrates a block in the secretion channel that is eliminated by calcium depletion. Further, the striking homology between different members of the YscU/FlhB family suggests that this protein family possess regulatory functions also in other bacteria using comparable mechanisms. PMID:23185318

  15. CALCIUM-INDUCED SUPRAMOLECULAR STRUCTURES IN THE CALCIUM CASEINATE SYSTEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The molecular details deciphering the spontaneous calcium-induced protein aggregation process in the calcium caseinate system remain obscure. Understanding this complex process could lead to potential new applications of this important food ingredient. In this work, we studied calcium-induced supra...

  16. Calcium Content of Common Foods

    MedlinePlus

    ... 130 Waffle 80 g 47 Meat, fish and eggs Food Serving Size Calcium (mg) Egg 50 g 27 Red meat 120 g 7 ... foods Food Serving Size Calcium (mg) Quiche (cheese, eggs) 200 g 212 Omelette with cheese 120 g ...

  17. Children's Bone Health and Calcium

    MedlinePlus

    ... Trials Resources and Publications Children's Bone Health and Calcium: Condition Information Skip sharing on social media links ... straight, walk, run, and lead an active life. Calcium is one of the key dietary building blocks ...

  18. Intestinal Stem Cells: Got Calcium?

    PubMed

    Nászai, Máté; Cordero, Julia B

    2016-02-01

    Calcium ions are well-known intracellular signalling molecules. A new study identifies local cytoplasmic calcium as a central integrator of metabolic and proliferative signals in Drosophila intestinal stem cells. PMID:26859268

  19. Calcium carbonate with magnesium overdose

    MedlinePlus

    The combination of calcium carbonate and magnesium is commonly found in antacids. These medicines provide heartburn relief. Calcium carbonate with magnesium overdose occurs when someone takes more than the ...

  20. Microvascular disease precedes the decline in renal function in the streptozotocin-induced diabetic rat

    PubMed Central

    Maric-Bilkan, Christine; Flynn, Elizabeth R.

    2012-01-01

    Diabetic nephropathy is a progressive and generalized vasculopathic condition associated with abnormal angiogenesis. We aim to determine whether changes in renal microvascular (MV) density correlate with and play a role in the progressive deterioration of renal function in diabetes. We hypothesize that MV changes represent the early steps of renal injury that worsen as diabetes progresses, initiating a vicious circle that leads to irreversible renal injury. Male nondiabetic (ND) or streptozotocin-induced diabetic (D) Sprague-Dawley rats were followed for 4 or 12 wk. Renal blood flow and glomerular filtration rate (GFR) were measured by PAH and 125I-[iothalamate], respectively. Renal MV density was quantified ex vivo using three-dimensional micro computed tomography and JG-12 immunoreactivity. Vascular endothelial growth factor (VEGF) levels (ELISA) and expression of VEGF receptors and factors involved in MV remodeling were quantified in renal tissue by Western blotting. Finally, renal morphology was investigated by histology. Four weeks of diabetes was associated with increased GFR, accompanied by a 34% reduction in renal MV density and augmented renal VEGF levels. However, at 12 wk, while GFR remained similarly elevated, reduction of MV density was more pronounced (75%) and associated with increased MV remodeling, renal fibrosis, but unchanged renal VEGF compared with ND at 12 wk. The damage, loss, and subsequent remodeling of the renal MV architecture in the diabetic kidney may represent the initiating events of progressive renal injury. This study suggests a novel concept of MV disease as an early instigator of diabetic kidney disease that may precede and likely promote the decline in renal function. PMID:22031855

  1. Reduction of orthophosphates loss in agricultural soil by nano calcium sulfate.

    PubMed

    Chen, Dong; Szostak, Paul; Wei, Zongsu; Xiao, Ruiyang

    2016-01-01

    Nutrient loss from soil, especially phosphorous (P) from farmlands to natural water bodies via surface runoff or infiltration, have caused significant eutrophication problems. This is because dissolved orthophosphates are usually the limiting nutrient for algal blooms. Currently, available techniques to control eutrophication are surprisingly scarce. Calcium sulfate or gypsum is a common soil amendment and has a strong complexation to orthophosphates. The results showed that calcium sulfate reduced the amount of water extractable P (WEP) through soil incubation tests, suggesting less P loss from farmlands. A greater decrease in WEP occurred with a greater dosage of calcium sulfate. Compared to conventional coarse calcium sulfate, nano calcium sulfate further reduced WEP by providing a much greater specific surface area, higher solubility, better contact with the fertilizer and the soil particles, and superior dispersibility. The enhancement of the nano calcium sulfate for WEP reduction is more apparent for a pellet- than a powdered- fertilizer. At the dosage of Ca/P weight ratio of 2.8, the WEP decreased by 31±5% with the nano calcium sulfate compared to 20±5% decrease with the coarse calcium sulfate when the pellet fertilizer was used. Computation of the chemical equilibrium speciation shows that calcium hydroxyapatite has the lowest solubility. However, other mineral phases such as hydroxydicalcium phosphate, dicalcium phosphate dihydrate, octacalcium phosphate, and tricalcium phosphate might form preceding to calcium hydroxyapatite. Since calcium sulfate is the major product of the flue gas desulfurization (FGD) process, this study demonstrates a potential beneficial reuse and reduction of the solid FGD waste.

  2. Reduction of orthophosphates loss in agricultural soil by nano calcium sulfate.

    PubMed

    Chen, Dong; Szostak, Paul; Wei, Zongsu; Xiao, Ruiyang

    2016-01-01

    Nutrient loss from soil, especially phosphorous (P) from farmlands to natural water bodies via surface runoff or infiltration, have caused significant eutrophication problems. This is because dissolved orthophosphates are usually the limiting nutrient for algal blooms. Currently, available techniques to control eutrophication are surprisingly scarce. Calcium sulfate or gypsum is a common soil amendment and has a strong complexation to orthophosphates. The results showed that calcium sulfate reduced the amount of water extractable P (WEP) through soil incubation tests, suggesting less P loss from farmlands. A greater decrease in WEP occurred with a greater dosage of calcium sulfate. Compared to conventional coarse calcium sulfate, nano calcium sulfate further reduced WEP by providing a much greater specific surface area, higher solubility, better contact with the fertilizer and the soil particles, and superior dispersibility. The enhancement of the nano calcium sulfate for WEP reduction is more apparent for a pellet- than a powdered- fertilizer. At the dosage of Ca/P weight ratio of 2.8, the WEP decreased by 31±5% with the nano calcium sulfate compared to 20±5% decrease with the coarse calcium sulfate when the pellet fertilizer was used. Computation of the chemical equilibrium speciation shows that calcium hydroxyapatite has the lowest solubility. However, other mineral phases such as hydroxydicalcium phosphate, dicalcium phosphate dihydrate, octacalcium phosphate, and tricalcium phosphate might form preceding to calcium hydroxyapatite. Since calcium sulfate is the major product of the flue gas desulfurization (FGD) process, this study demonstrates a potential beneficial reuse and reduction of the solid FGD waste. PMID:26372940

  3. Calcium and phosphorus fluxes during hemodialysis with low calcium dialysate.

    PubMed

    Hou, S H; Zhao, J; Ellman, C F; Hu, J; Griffin, Z; Spiegel, D M; Bourdeau, J E

    1991-08-01

    We evaluated the acute effects of varying dialysate calcium concentration on plasma concentrations and dialyzer fluxes of calcium and phosphorus in adult hemodialysis patients. Seven individuals with stable end-stage renal failure were dialyzed 4 hours, three times weekly. The effects of dialysates containing 1.75, 1.25, or 0.75 mmol/L (70.1, 50.1, or 30.1 mg/L) of calcium were compared. Each patient was studied once at each bath calcium concentration. Compared with the predialysis mean value of 2.27 mmol/L (9.1 mg/dL), plasma total calcium concentration increased, remained constant, or decreased with the 1.75-, 1.25-, or 0.75-mmol/L calcium dialysates, respectively. The 0.75-mmol/L calcium dialysate did not cause signs or symptoms of hypocalcemia (and the plasma calcium concentration did not fall below 1.80 mmol/L [7.2 mg/dL]). Plasma phosphorus concentrations decreased equally from a predialysis mean value of 2.16 mmol/L (6.7 mg/dL), regardless of the dialysate calcium concentration. After 4 hours of treatment with the three different dialysates, the cumulative calcium fluxes were significantly different. With 1.75 mmol/L calcium, mean bodily calcium accumulation was 21.9 mmol (879 mg). With 1.25 mmol/L, there was no net calcium flux. With 0.75 mmol/L, mean patient calcium loss was 5.8 mmol (231 mg). Mean phosphorus removal after 4 hours was 32.5 mmol (1,006 mg) and was unaffected by dialysate calcium concentration.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1867178

  4. Chromatin looping and eRNA transcription precede the transcriptional activation of gene in the β-globin locus

    PubMed Central

    Kim, Yea Woon; Lee, Sungkung; Yun, Jangmi; Kim, AeRi

    2015-01-01

    Enhancers are closely positioned with actively transcribed target genes by chromatin looping. Non-coding RNAs are often transcribed on active enhancers, referred to as eRNAs (enhancer RNAs). To explore the kinetics of enhancer–promoter looping and eRNA transcription during transcriptional activation, we induced the β-globin locus by chemical treatment and analysed cross-linking frequency between the β-globin gene and locus control region (LCR) and the amount of eRNAs transcribed on the LCR in a time course manner. The cross-linking frequency was increased after chemical induction but before the transcriptional activation of gene in the β-globin locus. Transcription of eRNAs was increased in concomitant with the increase in cross-linking frequency. These results show that chromatin looping and eRNA transcription precedes the transcriptional activation of gene. Concomitant occurrence of the two events suggests functional relationship between them. PMID:25588787

  5. Chromatin looping and eRNA transcription precede the transcriptional activation of gene in the β-globin locus.

    PubMed

    Kim, Yea Woon; Lee, Sungkung; Yun, Jangmi; Kim, AeRi

    2015-03-18

    Enhancers are closely positioned with actively transcribed target genes by chromatin looping. Non-coding RNAs are often transcribed on active enhancers, referred to as eRNAs (enhancer RNAs). To explore the kinetics of enhancer-promoter looping and eRNA transcription during transcriptional activation, we induced the β-globin locus by chemical treatment and analysed cross-linking frequency between the β-globin gene and locus control region (LCR) and the amount of eRNAs transcribed on the LCR in a time course manner. The cross-linking frequency was increased after chemical induction but before the transcriptional activation of gene in the β-globin locus. Transcription of eRNAs was increased in concomitant with the increase in cross-linking frequency. These results show that chromatin looping and eRNA transcription precedes the transcriptional activation of gene. Concomitant occurrence of the two events suggests functional relationship between them.

  6. Calcium biofortification of crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than half of the world's population is deficient in calcium (Ca), iron (Fe), iodine (I), magnesium (Mg), selenium (Se), or zinc (Zn). The consumption of plants, directly or via livestock, containing inadequate concentrations of particular minerals causes these deficiencies. Agronomic and geneti...

  7. Diet and calcium stones.

    PubMed Central

    Hughes, J; Norman, R W

    1992-01-01

    OBJECTIVE: To review the current literature on the dietary modification of urinary risk factors as a means of reducing the likelihood of recurrent stone formation and to develop practical dietary recommendations that might be useful to this end. DATA SOURCES: MEDLINE was searched for English-language articles published from 1983 to 1990. Additional references were selected from the bibliographies of identified articles. STUDY SELECTION: Nonrandomized trials and retrospective reviews were included because of a paucity of randomized controlled trials. DATA SYNTHESIS: Information on the dietary intake of calcium, oxalate, protein, sodium and fibre and on alcohol and fluid intake was used to develop practical guidelines on dietary modification. CONCLUSION: Dietary modification plays an important role in the reduction of urinary risk factors in patients with calcium stone disease of the urinary tract. As an initial form of prevention attention should be directed toward moderating the intake of calcium, oxalate, protein, sodium and alcohol and increasing the intake of fibre and water. Future research should include an assessment of the long-term reduction of dietary and urinary risk factors and the rates of recurrence of calcium stones. PMID:1310430

  8. Calcium silicate insulation structure

    DOEpatents

    Kollie, Thomas G.; Lauf, Robert J.

    1995-01-01

    An insulative structure including a powder-filled evacuated casing utilizes a quantity of finely divided synthetic calcium silicate having a relatively high surface area. The resultant structure-provides superior thermal insulating characteristics over a broad temperature range and is particularly well-suited as a panel for a refrigerator or freezer or the insulative barrier for a cooler or a insulated bottle.

  9. High Blood Calcium (Hypercalcemia)

    MedlinePlus

    ... as sarcoidosis • Hormone disorders, such as overactive thyroid (hyperthyroidism) • A genetic condition called familial hypocalciuric hypercalcemia • Kidney ... topics: www.hormone.org (search for PHPT, calcium, hyperthyroidism, or osteoporosis) • MedlinePlus (National Institutes of Health-NIH): ...

  10. Active and passive calcium transport systems in plant cells: Progress report, January 1986--June 1989

    SciTech Connect

    Sze, H.

    1989-01-01

    The objectives of this proposal are to identify and characterize active (energy-dependent) and passive calcium transport systems that work together to regulate calcium levels in the cytoplasm of plant cells. Several different energy-dependent Ca transport systems have been identified and characterized from oat root tissue (a monocot tissue) and carrot suspension cells (a dicot tissue). They are described in more detail below. I also have included in this progress report our continuing studies to understand the mode of action of the Helminthosporium maydis T toxin. This study was initially supported by a preceding DOE grant. The time needed to complete the study overlapped partly with the present grant period.

  11. Precedency control and other semantic integrity issues in a workbench database

    NASA Technical Reports Server (NTRS)

    Dampney, C. N. G.

    1983-01-01

    Most database systems model the current state of a system of real world discrete and simple entities together with their relationships. By examining instead a database system that is a workbench and models more complicated entities, a fresh perspective is gained. Specifically, semantic integrity is analysed. Four aspects distinct from physical integrity are identified, namely - access, failure, concurrency and precedency. Access control is shown to be the consequence of semantic interdependency between data and its matching semantic routines. Failure, concurrency precedency controls are concerned with preventing processes interfering with each other. Precedency is a new concept in the database context. It expresses a constraint between processes that act on the database. As processes create, update and delete entities they in general obey a partial ordering imposed by the semantics of their actions. Precedency control ensures that data remains consistent with respect to this partial order.

  12. Historical Uses of Meteoritic Metals as Precedent for Modern In-Situ Asteroid Mining

    NASA Astrophysics Data System (ADS)

    Krispin, D.; Mardon, A. A.; Fawcett, B. G.

    2016-08-01

    The strain on earth's resources of metal and the metallic density of meteorites mean that in situ asteroid mining is advisable. This has precedent: Use of meteoritic metal dates back to ancient times.

  13. Calcium aluminate in alumina

    NASA Astrophysics Data System (ADS)

    Altay, Arzu

    The properties of ceramic materials are determined not only by the composition and structure of the phases present, but also by the distribution of impurities, intergranular films and second phases. The phase distribution and microstructure both depend on the fabrication techniques, the raw materials used, the phase-equilibrium relations, grain growth and sintering processes. In this dissertation research, various approaches have been employed to understand fundamental phenomena such as grain growth, impurity segregation, second-phase formation and crystallization. The materials system chosen was alumina intentionally doped with calcium. Atomic-scale structural analyses of grain boundaries in alumina were carried on the processed samples. It was found that above certain calcium concentrations, CA6 precipitated as a second phase at all sintering temperatures. The results also showed that abnormal grain growth can occur after precipitation and it is not only related to the calcium level, but it is also temperature dependent. In order to understand the formation mechanism of CA6 precipitates in calcium doped alumina samples, several studies have been carried out using either bulk materials or thin films The crystallization of CA2 and CA6 powders has been studied. Chemical processing techniques were used to synthesize the powders. It was observed that CA2 powders crystallized directly, however CA6 powders crystallized through gamma-Al 2O3 solid solution. The results of energy-loss near-edge spectrometry confirmed that gamma-Al2O3 can dissolve calcium. Calcium aluminate/alumina reaction couples have also been investigated. All reaction couples were heat treated following deposition. It was found that gamma-Al2O3 was formed at the interface as a result of the interfacial reaction between the film and the substrate. gamma-Al 2O3 at the interface was stable at much higher temperatures compared to the bulk gamma-Al2O3 formed prior to the CA6 crystallization. In order to

  14. The Plasma Membrane Calcium Pump

    NASA Technical Reports Server (NTRS)

    Rasmussen, H.

    1983-01-01

    Three aspect of cellular calcium metabolism in animal cells was discussed including the importance of the plasma membrane in calcium homeostasis, experiments dealing with the actual mechanism of the calcium pump, and the function of the pump in relationship to the mitochondria and to the function of calmodulin in the intact cell.

  15. Impregnating Coal With Calcium Carbonate

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K.; Voecks, Gerald E.; Gavalas, George R.

    1991-01-01

    Relatively inexpensive process proposed for impregnating coal with calcium carbonate to increase rates of gasification and combustion of coal and to reduce emission of sulfur by trapping sulfur in calcium sulfide. Process involves aqueous-phase reactions between carbon dioxide (contained within pore network of coal) and calcium acetate. Coal impregnated with CO2 by exposing it to CO2 at high pressure.

  16. New reference values for calcium.

    PubMed

    2013-01-01

    The nutrition societies of Germany, Austria and Switzerland are the joint editors of the 'reference values for nutrient intake'. They have revised the reference values for the intake of calcium and published them in June 2013. The reference values for the calcium intake for infants are derived from the calcium content of breast milk. For infants from 4 to <12 months of age, the calcium intake from solid foods is included in addition to the calcium intake from breast milk. Thus, the reference values for infants are estimated values; they are 220 mg/day for infants to <4 months and 330 mg/day for infants from 4 to <12 months of age. As a parameter for determining the calcium requirement in children and adolescents, calcium retention is taken into account. The average requirement is calculated by the factorial method. A balanced calcium metabolism is calculated based upon calcium balance studies and used as a parameter for the determination of the calcium requirement in adults. On the basis of the average requirement, recommended calcium intake levels for children, adolescents and adults are derived. Depending on age, the recommended calcium intake ranges between 600 mg/day for children aged 1 to <4 years and 1,200 mg/day for adolescents aged 13 to <19 years; for adults, it is 1,000 mg/day. PMID:24356454

  17. Calcium-mediated inactivation of calcium current in Paramecium.

    PubMed

    Brehm, P; Eckert, R; Tillotson, D

    1980-09-01

    1. The Ca current seen in response to depolarization was investigated in Paramecium caudatum under voltage clamp. Inactivation of the current was measured with the double pulse method; a fixed test pulse of an amplitude sufficient to evoke maximal inward current was preceded by a conditioning pulse of variable amplitude (0-120 mV).2. The amplitude of the current recorded during the test pulse was related to the potential of the conditioning pulse. Reduction of test pulse current was taken as an index of Ca current inactivation. The current recorded during a test pulse showed a progressive decrease to a minimum as the potential of the conditioning pulse approached +10 to +30 mV. Further increase in conditioning pulse amplitude was accompanied by a progressive restoration of the test pulse current. Conditioning pulses near the calcium equilibrium potential had only a slight inactivating effect on the test pulse current.3. Injection of a mixture of Cs and TEA which blocked late outward current had essentially no effect on the inward current or its inactivation.4. Elevation of external Ca from 0.5 to 5 mM was accompanied by increased inactivation of the test pulse current. The enhanced inactivation of the test pulse current was approximately proportional to the increase in current recorded during the conditioning pulse.5. Following injection of the Ca chelating agent, EGTA, the inactivation of the test pulse current was diminished; in addition, the transient inward current relaxed slightly more slowly, and the transient was followed by a steady net inward current.6. The time course of recovery from inactivation in the double pulse experiment approximated a single exponential having a time constant of 80-110 msec. Injection of EGTA shortened the time constant by as much as 50%.7. It is concluded that interference with the entry of Ca or enhanced removal of intracellular free Ca(2+) interferes with the process of Ca current inactivation, while enhanced entry of Ca

  18. 17 CFR 240.11a1-1(T) - Transactions yielding priority, parity, and precedence.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... section 11(a)(1) of the Act or specified in 17 CFR 240.11a1-4(T) shall be deemed to be revenue derived..., parity, and precedence. 240.11a1-1(T) Section 240.11a1-1(T) Commodity and Securities Exchanges SECURITIES... (rule 11a-1) § 240.11a1-1(T) Transactions yielding priority, parity, and precedence. (a) A...

  19. 17 CFR 240.11a1-1(T) - Transactions yielding priority, parity, and precedence.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... section 11(a)(1) of the Act or specified in 17 CFR 240.11a1-4(T) shall be deemed to be revenue derived..., parity, and precedence. 240.11a1-1(T) Section 240.11a1-1(T) Commodity and Securities Exchanges SECURITIES... (rule 11a-1) § 240.11a1-1(T) Transactions yielding priority, parity, and precedence. (a) A...

  20. 17 CFR 240.11a1-1(T) - Transactions yielding priority, parity, and precedence.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... section 11(a)(1) of the Act or specified in 17 CFR 240.11a1-4(T) shall be deemed to be revenue derived..., parity, and precedence. 240.11a1-1(T) Section 240.11a1-1(T) Commodity and Securities Exchanges SECURITIES... (rule 11a-1) § 240.11a1-1(T) Transactions yielding priority, parity, and precedence. (a) A...

  1. 17 CFR 240.11a1-1(T) - Transactions yielding priority, parity, and precedence.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... section 11(a)(1) of the Act or specified in 17 CFR 240.11a1-4(T) shall be deemed to be revenue derived..., parity, and precedence. 240.11a1-1(T) Section 240.11a1-1(T) Commodity and Securities Exchanges SECURITIES... (rule 11a-1) § 240.11a1-1(T) Transactions yielding priority, parity, and precedence. (a) A...

  2. 17 CFR 240.11a1-1(T) - Transactions yielding priority, parity, and precedence.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... section 11(a)(1) of the Act or specified in 17 CFR 240.11a1-4(T) shall be deemed to be revenue derived..., parity, and precedence. 240.11a1-1(T) Section 240.11a1-1(T) Commodity and Securities Exchanges SECURITIES... (rule 11a-1) § 240.11a1-1(T) Transactions yielding priority, parity, and precedence. (a) A...

  3. [Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?].

    PubMed

    de Jonge, H J M Henk-Marijn; Gans, R O B Rijk; Huls, Gerwin

    2012-01-01

    Various calcium supplements are available for patients who have an indication for calcium suppletion. American guidelines and UpToDate recommend prescribing calcium citrate to patients who use antacids The rationale for this advice is that water-insoluble calcium carbonate needs acid for adequate absorption. No convincing scientific evidence supporting the advice to prescribe calcium citrate instead of calcium carbonate to patients who also take antacids is available, and therefore deserves further investigation. On the contrary, the fact that calcium carbonate does not need acid in order to be absorbed, has also not been proven. In clinical practise, it appears important that calcium is taken with meals in order to improve its absorption. PMID:22914054

  4. [Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?].

    PubMed

    de Jonge, H J M Henk-Marijn; Gans, R O B Rijk; Huls, Gerwin

    2012-01-01

    Various calcium supplements are available for patients who have an indication for calcium suppletion. American guidelines and UpToDate recommend prescribing calcium citrate to patients who use antacids The rationale for this advice is that water-insoluble calcium carbonate needs acid for adequate absorption. No convincing scientific evidence supporting the advice to prescribe calcium citrate instead of calcium carbonate to patients who also take antacids is available, and therefore deserves further investigation. On the contrary, the fact that calcium carbonate does not need acid in order to be absorbed, has also not been proven. In clinical practise, it appears important that calcium is taken with meals in order to improve its absorption.

  5. Transient Deformation Preceding and Following the June 2000 Earthquake Sequence in Southwest Iceland

    NASA Astrophysics Data System (ADS)

    Arnadottir, T.; Miyazaki, S.; Geirsson, H.

    2005-12-01

    Two Mw=6.5 earthquakes and several M~5 triggered earthquakes occurred in south Iceland over a period of 4 days in June 2000. The first main shock on June 17, triggered increased seismicity over a large area and significant slip on at least three distinct faults on the Reykjanes Peninsula, up to 90 km to the west of the main shock epicenter. Crustal deformation signals due to the earthquake sequence were observed with campaign and continuous GPS and InSAR. Seismic and geodetic data confirm that the faults that ruptured in the June 2000 sequence are oriented N-S, almost perpendicular to the trend of the plate boundary, with primarily right-lateral strike slip motion. The geodetic data from the Reykjanes Peninsula suggest that the event near Kleifarvatn had a significantly larger moment than seismic estimates, indicating a component of aseismic slip on the fault lasting no more than several hours. Kinematic GPS analysis of 30 second data from the two closest continuous GPS station in Iceland is used to constrain the timing of the aseismic component of the deformation. Transient deformation in the area of the two main shocks was observed with InSAR and GPS. A short term transient observed by InSAR has been explained by poro-elastic rebound due to post-earthquake pore-pressure changes. The longer term deformation signal can be explained by either afterslip at 8-14 km depth or viscoelastic relaxation of the lower crust and upper mantle in response to the coseismic stress changes. The June 2000 earthquake sequence was preceded by intrusive and intense seismic activity at the Hengill triple junction and an eruption at Hekla volcano, located at the western and eastern ends of the south Iceland seismic zone, respectively. Coulomb stress change calculations indicate that the Hengill intrusion decreased the stress at the western end of the SISZ. These events illustrate the importance of increasing the spatial and temporal resolution of continuous monitoring of crustal

  6. Intraclonal heterogeneity is a critical early event in the development of myeloma and precedes the development of clinical symptoms.

    PubMed

    Walker, B A; Wardell, C P; Melchor, L; Brioli, A; Johnson, D C; Kaiser, M F; Mirabella, F; Lopez-Corral, L; Humphray, S; Murray, L; Ross, M; Bentley, D; Gutiérrez, N C; Garcia-Sanz, R; San Miguel, J; Davies, F E; Gonzalez, D; Morgan, G J

    2014-02-01

    The mechanisms involved in the progression from monoclonal gammopathy of undetermined significance (MGUS) and smoldering myeloma (SMM) to malignant multiple myeloma (MM) and plasma cell leukemia (PCL) are poorly understood but believed to involve the sequential acquisition of genetic hits. We performed exome and whole-genome sequencing on a series of MGUS (n=4), high-risk (HR)SMM (n=4), MM (n=26) and PCL (n=2) samples, including four cases who transformed from HR-SMM to MM, to determine the genetic factors that drive progression of disease. The pattern and number of non-synonymous mutations show that the MGUS disease stage is less genetically complex than MM, and HR-SMM is similar to presenting MM. Intraclonal heterogeneity is present at all stages and using cases of HR-SMM, which transformed to MM, we show that intraclonal heterogeneity is a typical feature of the disease. At the HR-SMM stage of disease, the majority of the genetic changes necessary to give rise to MM are already present. These data suggest that clonal progression is the key feature of transformation of HR-SMM to MM and as such the invasive clinically predominant clone typical of MM is already present at the SMM stage and would be amenable to therapeutic intervention at that stage. PMID:23817176

  7. Coordination of cellular events that precede reproductive onset in Acetabularia acetabulum: evidence for a 'loop' in development.

    PubMed

    Runft, L L; Mandoli, D F

    1996-04-01

    Amputated apices from vegetative wildtype cells of the uninucleate green alga Acetabularia acetabulum can differentiate a reproductive structure of 'cap' in the absence of the nucleus (Hämmerling, J. (1932) Biologisches Zentralblatt 52, 42-61). To define the limits of the ability of wildtype cells to control reproductive differentiation, we determined when during development apices from wildtype cells first acquired the ability to make a cap in the absence of the nucleus and, conversely, when cells with a nucleus lost the ability to recover from the loss of their apices. To see when the apex acquired the ability to make a cap without the nucleus, we removed apices from cells varying either the developmental age of the cells or the cellular volume left with the apex. Cells must have attained the adult phase of development before the enucleate apex could survive amputation and make a cap. Apices removed from cells early in adult growth required more cell volume to make a cap without the nucleus than did apices removed from cells late in adult growth. To define the limits of the cell to recapitulate development when reproduction falters, we analyzed development in cells whose caps either had been amputated or had spontaneously aborted. After loss of the first cap, cells repeated part of vegetative growth and then made a second cap. The ability to make a second cap after amputation of the first one was lost 15-20 days after cap initiation. Our data suggest that internal cues, cell age and size, are used to regulate reproductive onset in Acetabularia acetabulum and add to our understanding of how reproduction is coordinated in this giant cell.

  8. Towards the Physics of Calcium Signalling in Plants

    PubMed Central

    Vaz Martins, Teresa; Evans, Matthew J.; Woolfenden, Hugh C.; Morris, Richard J.

    2013-01-01

    Calcium is an abundant element with a wide variety of important roles within cells. Calcium ions are inter- and intra-cellular messengers that are involved in numerous signalling pathways. Fluctuating compartment-specific calcium ion concentrations can lead to localised and even plant-wide oscillations that can regulate downstream events. Understanding the mechanisms that give rise to these complex patterns that vary both in space and time can be challenging, even in cases for which individual components have been identified. Taking a systems biology approach, mathematical and computational techniques can be employed to produce models that recapitulate experimental observations and capture our current understanding of the system. Useful models make novel predictions that can be investigated and falsified experimentally. This review brings together recent work on the modelling of calcium signalling in plants, from the scale of ion channels through to plant-wide responses to external stimuli. Some in silico results that have informed later experiments are highlighted. PMID:27137393

  9. Imaging Calcium in Drosophila at Egg Activation.

    PubMed

    Derrick, Christopher J; York-Andersen, Anna H; Weil, Timothy T

    2016-01-01

    Egg activation is a universal process that includes a series of events to allow the fertilized egg to complete meiosis and initiate embryonic development. One aspect of egg activation, conserved across all organisms examined, is a change in the intracellular concentration of calcium (Ca(2+)) often termed a 'Ca(2+) wave'. While the speed and number of oscillations of the Ca(2+) wave varies between species, the change in intracellular Ca(2+) is key in bringing about essential events for embryonic development. These changes include resumption of the cell cycle, mRNA regulation, cortical granule exocytosis, and rearrangement of the cytoskeleton. In the mature Drosophila egg, activation occurs in the female oviduct prior to fertilization, initiating a series of Ca(2+)-dependent events. Here we present a protocol for imaging the Ca(2+) wave in Drosophila. This approach provides a manipulable model system to interrogate the mechanism of the Ca(2+) wave and the downstream changes associated with it. PMID:27584955

  10. Cellular Mechanisms of Calcium-Mediated Triggered Activity

    NASA Astrophysics Data System (ADS)

    Song, Zhen

    proteins. How those various factors interact synergistically to promote DADs is not well understood. Furthermore, at an even more basic level, it remains unclear to what degree spontaneous Ca2+ release and the appearance of DADs are deterministic, meaning reproducible under identical conditions, or inherently stochastic like nucleation in the physical context of phase transitions. In this thesis, we use and further develop a biologically detailed computational model to investigate basic aspects of TA in isolated heart cells (cardiac myocytes). Isolated cells can be obtained by enzymatic dissociation of heart tissue and studied experimentally using standard electrophysiological recording methods and confocal imaging of Ca2+ dynamics. Hence they provide a well controlled setting to investigate the generation of DADs under well controlled conditions. Our computational model captures essential aspects of the hierarchical architecture of ventricular myocytes, which consists of a large number of approximately 20,000 to 50,000 regularly spaced submicron regions containing clusters of 50-100 Ryanodine receptor (RyR) Ca2+ release channels. Each of those regions acts as a discrete "calcium release unit'' (CRU). Therefore our model allows us to address for the first time quantitatively the fundamental question of whether Ca2+ release, which is highly stochastic at the level of a single calcium release unit, is stochastic or deterministic at the whole cell level where the Ca 2+ signal is the summation of releases from a large number of units. Addressing this question is the focus of the first part of this thesis. Our results demonstrate that both the initiation and termination of TA are highly stochastic at the whole cell level due to the spatiotemporal organization of discrete release events into multiple Ca2+ waves. Our results allow us to characterize the probability distributions that govern the number of DADs preceding a triggered action potential and the number of triggered

  11. Calcium signaling in taste cells.

    PubMed

    Medler, Kathryn F

    2015-09-01

    The sense of taste is a common ability shared by all organisms and is used to detect nutrients as well as potentially harmful compounds. Thus taste is critical to survival. Despite its importance, surprisingly little is known about the mechanisms generating and regulating responses to taste stimuli. All taste responses depend on calcium signals to generate appropriate responses which are relayed to the brain. Some taste cells have conventional synapses and rely on calcium influx through voltage-gated calcium channels. Other taste cells lack these synapses and depend on calcium release to formulate an output signal through a hemichannel. Beyond establishing these characteristics, few studies have focused on understanding how these calcium signals are formed. We identified multiple calcium clearance mechanisms that regulate calcium levels in taste cells as well as a calcium influx that contributes to maintaining appropriate calcium homeostasis in these cells. Multiple factors regulate the evoked taste signals with varying roles in different cell populations. Clearly, calcium signaling is a dynamic process in taste cells and is more complex than has previously been appreciated. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.

  12. Calcium Signaling throughout the Toxoplasma gondii Lytic Cycle: A STUDY USING GENETICALLY ENCODED CALCIUM INDICATORS.

    PubMed

    Borges-Pereira, Lucas; Budu, Alexandre; McKnight, Ciara A; Moore, Christina A; Vella, Stephen A; Hortua Triana, Miryam A; Liu, Jing; Garcia, Celia R S; Pace, Douglas A; Moreno, Silvia N J

    2015-11-01

    Toxoplasma gondii is an obligate intracellular parasite that invades host cells, creating a parasitophorous vacuole where it communicates with the host cell cytosol through the parasitophorous vacuole membrane. The lytic cycle of the parasite starts with its exit from the host cell followed by gliding motility, conoid extrusion, attachment, and invasion of another host cell. Here, we report that Ca(2+) oscillations occur in the cytosol of the parasite during egress, gliding, and invasion, which are critical steps of the lytic cycle. Extracellular Ca(2+) enhances each one of these processes. We used tachyzoite clonal lines expressing genetically encoded calcium indicators combined with host cells expressing transiently expressed calcium indicators of different colors, and we measured Ca(2+) changes in both parasites and host simultaneously during egress. We demonstrated a link between cytosolic Ca(2+) oscillations in the host and in the parasite. Our approach also allowed us to measure two new features of motile parasites, which were enhanced by Ca(2+) influx. This is the first study showing, in real time, Ca(2+) signals preceding egress and their direct link with motility, an essential virulence trait.

  13. Onset and Offset of Aversive Events Establish Distinct Memories Requiring Fear and Reward Networks

    ERIC Educational Resources Information Center

    Andreatta, Marta; Fendt, Markus; Muhlberger, Andreas; Wieser, Matthias J.; Imobersteg, Stefan; Yarali, Ayse; Gerber, Bertram; Pauli, Paul

    2012-01-01

    Two things are worth remembering about an aversive event: What made it happen? What made it cease? If a stimulus precedes an aversive event, it becomes a signal for threat and will later elicit behavior indicating conditioned fear. However, if the stimulus is presented upon cessation of the aversive event, it elicits behavior indicating…

  14. Fruit Calcium: Transport and Physiology.

    PubMed

    Hocking, Bradleigh; Tyerman, Stephen D; Burton, Rachel A; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  15. Fruit Calcium: Transport and Physiology

    PubMed Central

    Hocking, Bradleigh; Tyerman, Stephen D.; Burton, Rachel A.; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  16. Subgroup analysis for the risk of cardiovascular disease with calcium supplements.

    PubMed

    Radford, Loretta T; Bolland, Mark J; Gamble, Greg D; Grey, Andrew; Reid, Ian R

    2013-01-01

    Calcium supplements have been reported to increase the risk of myocardial infarction (MI). We wished to determine whether the effects of calcium supplements on cardiovascular risk vary across different population groups. We modeled the effect of calcium (with or without vitamin D) on the time to incident cardiovascular events in pre-specified subgroups based on age, dietary calcium intake, body mass index, smoking history, history of hypertension, diabetes and prevalent cardiovascular disease, using interaction terms in Cox proportional hazards models in two randomized controlled trial data sets-our re-analysis of the Women's Health Initiative Calcium and Vitamin D study (WHI CaD), and our pooled patient-level meta-analysis of trials of calcium supplements with or without vitamin D. For women in WHI CaD not taking calcium supplements at randomization (n=16 718), we found no significant interactions between treatment allocation, the risk of MI, stroke or coronary revascularization, or any of the baseline variables. In the pooled patient-level data set of six trials of calcium with or without vitamin D (n=24 869), there were also no significant interactions between treatment allocation, risk of MI or stroke, and any of the baseline variables. We found no evidence that the increased cardiovascular risk from calcium supplements differs across varying patient subpopulations. These findings suggest that targeted prescription of calcium supplements to specific population subgroups, such as younger people and those with low dietary calcium intake, should not be endorsed.

  17. Complexometric Determination of Calcium

    NASA Astrophysics Data System (ADS)

    Nielsen, S. Suzanne

    Ethylenediaminetetraacetate (EDTA) complexes with numerous mineral ions, including calcium and magnesium. This reaction can be used to determine the amount of these minerals in a sample by a complexometric titration. Endpoints in the titration are detected using indicators that change color when they complex with mineral ions. Calmagite and eriochrome black T (EBT) are such indicators that change from blue to pink when they complex with calcium and magnesium. In the titration of a mineral-containing solution with EDTA, the solution turns from pink to blue at the endpoint with either indicator. The pH affects a complexometric EDTA titration in several ways, and must be carefully controlled. A major application of EDTA titration is testing the hardness of water, for which the method described is an official one (Standard Methods for the Examination of Water and Wastewater, Method 2340C; AOAC Method 920.196).

  18. DISTILLATION OF CALCIUM

    DOEpatents

    Barton, J.

    1954-07-27

    This invention relates to an improvement in the process for the purification of caicium or magnesium containing an alkali metal as impurity, which comprises distiiling a batch of the mixture in two stages, the first stage distillation being carried out in the presence of an inert gas at an absolute pressure substantially greater than the vapor pressure of calcium or maguesium at the temperature of distillation, but less than the vaper pressure at that temperature of the alkali metal impurity so that only the alkali metal is vaporized and condensed on a condensing surface. A second stage distilso that substantially only the calcium or magnesium distills under its own vapor pressure only and condenses in solid form on a lower condensing surface.

  19. Synthesis of calcium superoxide

    NASA Technical Reports Server (NTRS)

    Rewick, R. T.; Blucher, W. G.; Estacio, P. L.

    1972-01-01

    Efforts to prepare Ca(O2) sub 2 from reactions of calcium compounds with 100% O3 and with O(D-1) atoms generated by photolysis of O3 at 2537 A are described. Samples of Ca(OH) sub 2, CaO, CaO2, Ca metal, and mixtures containing suspected impurities to promote reaction have been treated with excess O3 under static and flow conditions in the presence and absence of UV irradiation. Studies with KO2 suggest that the superoxide anion is stable to radiation at 2537 A but reacts with oxygen atoms generated by the photolysis of O3 to form KO3. Calcium superoxide is expected to behave in an analogous.

  20. Calcium hydroxylapatite: Radiesse.

    PubMed

    Ahn, Min S

    2007-02-01

    Among the array of choices for aesthetic soft tissue fillers, Radiesse occupies a unique niche as a safe, easily administered, "semi-permanent" material. Composed of calcium hydroxylapatite in a gel matrix, it has a proven safety profile and has been approved by the US Food and Drug Administration for use in the nasolabial folds and for HIV lipoatrophy. Radiesse have evolved quickly into a effective filler for moderately deep facial folds with high patient and physician approval.

  1. Calcium Signaling in Taste Cells

    PubMed Central

    Medler, Kathryn F.

    2014-01-01

    The sense of taste is a common ability shared by all organisms and is used to detect nutrients as well as potentially harmful compounds. Thus taste is critical to survival. Despite its importance, surprisingly little is known about the mechanisms generating and regulating responses to taste stimuli. All taste responses depend on calcium signals to generate appropriate responses which are relayed to the brain. Some taste cells have conventional synapses and rely on calcium influx through voltage-gated calcium channels. Other taste cells lack these synapses and depend on calcium release to formulate an output signal through a hemichannel. Beyond establishing these characteristics, few studies have focused on understanding how these calcium signals are formed. We identified multiple calcium clearance mechanisms that regulate calcium levels in taste cells as well as a calcium influx that contributes to maintaining appropriate calcium homeostasis in these cells. Multiple factors regulate the evoked taste signals with varying roles in different cell populations. Clearly, calcium signaling is a dynamic process in taste cells and is more complex than has previously been appreciated. PMID:25450977

  2. Biliary calcium and gallstone formation.

    PubMed

    Moore, E W

    1990-09-01

    The purpose of this paper is to present a brief overview of the current status of the field of biliary calcium and the role of calcium in the formation and maturation of gallstones. The study of free Ca+(+) ions in bile by electrochemical potentiometric measurements using Ca+(+)-selective ion-exchange electrodes is a relatively new field, but much progress has been made in the past few years. Using this powerful analytical tool, new concepts and findings have arisen in almost every aspect of biliary calcium. Although the current symposium is targeted primarily toward cholesterol gallstones, there are several areas in which understanding of biliary calcium may significantly contribute to a better understanding of the pathogenesis of cholesterol, as well as "pigment" (calcium salt), gallstones. Five broad areas are considered in relation to biliary calcium: (a) physiology (calcium entry into bile), (b) biophysics (the regulation of biliary free [Ca+(+)] as related to Gibbs-Donnan equilibria, (c) physical chemistry (the physicochemical state of calcium in bile, (d) thermodynamics (calcium solubility in bile), and (e) kinetics (pronucleating and antinucleating factors and metastable states). With more specific reference to cholesterol stones, consideration is also made of (a) the calcium salt "seed" hypothesis in cholesterol stone pathogenesis; (b) the interactions of Ca+(+) with phospholipid-cholesterol vesicles, with consideration of possible structural requirements and (c) thermodynamic and kinetic factors as related to peripheral or "eggshell" calcification of existing cholesterol stones. PMID:2210651

  3. Outcome after autologous stem cell transplantation for multiple myeloma in patients with preceding plasma cell disorders.

    PubMed

    Kumar, Shaji K; Dingli, David; Lacy, Martha Q; Dispenzieri, Angela; Hayman, Suzanne R; Buadi, Francis K; Rajkumar, S Vincent; Litzow, Mark R; Gertz, Morie A

    2008-04-01

    A third of patients with multiple myeloma (MM) have a preceding diagnosis of plasma cell proliferative disorder (PCPD), mostly monoclonal gammopathy of undetermined significance (MGUS), smoldering MM (SMM) or plasmacytoma. While autologous stem cell transplantation (SCT) improves survival in MM, it is not clear if patients with preceding PCPD have a different outcome. We identified 151 patients with preceding PCPD from among 804 patients undergoing SCT, and their outcomes were compared. The response rates, including complete responses, were similar between the groups. Patients with a preceding diagnosis of MGUS had longer time to progression (TTP; 27.5 months vs. 17.2 months, P = 0.01), and longer overall survival (OS) from transplant (80.2 months vs. 48.3 months, P = 0.03) compared to those with de novo myeloma. However no differences were seen among those with a preceding diagnosis of SMM or plasmacytoma in terms of TTP or OS from transplant when compared to those with de novo myeloma. Multivariate analysis indicated that the presence of MGUS prior to myeloma was prognostic for post-transplant relapse independent of other known risk factors. Patients with pre-existing MGUS prior to myeloma diagnosis have a better outcome following HDT, reflecting more indolent disease and a favourable biology than those presenting with de novo myeloma. PMID:18318761

  4. The Role of Animacy and Thematic Relationships in Processing Active English Sentences: Evidence from Event-Related Potentials

    ERIC Educational Resources Information Center

    Kuperberg, Gina R.; Kreher, Donna A.; Sitnikova, Tatiana; Caplan, David N.; Holcomb, Phillip J.

    2007-01-01

    Recent event-related potential studies report a P600 effect to incongruous verbs preceded by semantically associated inanimate noun-phrase (NP) arguments, e.g., "eat" in "At breakfast the eggs would eat...". This P600 effect may reflect the processing cost incurred when semantic-thematic relationships between critical verbs and their preceding NP…

  5. Transformational Events

    ERIC Educational Resources Information Center

    Denning, Peter J.; Hiles, John E.

    2006-01-01

    Transformational Events is a new pedagogic pattern that explains how innovations (and other transformations) happened. The pattern is three temporal stages: an interval of increasingly unsatisfactory ad hoc solutions to a persistent problem (the "mess"), an offer of an invention or of a new way of thinking, and a period of widespread adoption and…

  6. Maintenance Event

    Atmospheric Science Data Center

    2014-07-22

    Time:  08:00 am - 08:30 am EDT Event Impact:  Science Directorate websites will ... outage Thursday morning, 7/24, to perform upgrades to the web environment and are expected to be down for about 30 minutes. ...

  7. An Ocean Acidification Pulse in the Pre-onset Carbon Isotope Excursion Preceding the Paleocene-Eocene Thermal Maximum

    NASA Astrophysics Data System (ADS)

    Robinson, M. M.; Self-Trail, J. M.; Willard, D. A.; Stassen, P.; Spivey, W.

    2015-12-01

    The Paleocene-Eocene Thermal Maximum (PETM; ~55.5 Ma) is recognized globally in marine sediments by a carbonate dissolution zone, the extinction or turnover of benthic taxa, and a radiation of planktic excursion taxa, all accompanied by a rapid-onset, negative carbon isotope excursion (CIE). The cause and nature of the massive carbon release leading to this extreme climate event remains under debate. Regardless of cause, the environmental and ecosystem changes centered on the PETM are the subject of much study because they provide an analog to modern deteriorating conditions associated with the ongoing rise in atmospheric carbon dioxide. We present evidence from sediments of the South Dover Bridge core, deposited on the U.S. mid-Atlantic shelf, for an ocean acidification event in the latest Paleocene that coincides with a relatively small (-2‰) negative carbon isotope excursion (CIE) that precedes the larger (-4‰) Paleocene-Eocene CIE onset. Planktic foraminifers during this pre-onset event (POE) show post-deposition dissolution in which the coarsely cancellate and muricate wall textures characteristic of many Late Paleocene species have been dissolved away, leaving smooth, thin-walled specimens often with collapsed chambers. In addition, we document biotic responses in benthic, planktic, and terrestrial communities to the POE, including shifts in foraminifer and pollen assemblages and adaptations in calcareous nannofossil species in response to environmental perturbations. A complete recovery is evident between the POE and CIE in both the carbon isotopic signal and in the biotic response, providing additional evidence not only for a pulsed carbon release, but also for a more rapid rate of carbon release than is suggested by a single pulse over a longer period of time. The timing, nature and magnitude of ecological changes during the less extreme POE shallow water acidification event may help to define the ecological tipping point of shallow marine ecosystems.

  8. Calcium and bone health--goodbye, calcium supplements?

    PubMed

    Ströhle, A; Hadji, P; Hahn, A

    2015-10-01

    This review assesses (1) the potential role of calcium supplements in the prevention and treatment of osteoporosis and osteoporotic fractures, and (2) the safety of calcium supplements with respect to cardiovascular health as well. With regard to (1), a total calcium intake of < 800 mg/day is associated with increased loss of bone mineral density in peri- and postmenopausal women with an increase in fracture risk. Hereby, the effect of calcium supplements on fracture prevention is dependent primary on baseline calcium intake. The strongest protective effect has been reported in individuals with a calcium intake < 700 mg/day and in high-risk groups. A calcium intake of about 1000-1200 mg/day seems to be sufficient for general fracture prevention. With regard to (2), an analysis of the data based on the Hill criteria does not demonstrate convincing evidence that calcium supplements increase cardiovascular risk. In the long term, total calcium intake of 2500 mg/day (from food and supplements) continues to be classified as safe. This value should not be exceeded for an extended period of time. PMID:25689871

  9. Calcium signaling in neocortical development.

    PubMed

    Uhlén, Per; Fritz, Nicolas; Smedler, Erik; Malmersjö, Seth; Kanatani, Shigeaki

    2015-04-01

    The calcium ion (Ca(2+) ) is an essential second messenger that plays a pivotal role in neurogenesis. In the ventricular zone (VZ) of the neocortex, neural stem cells linger to produce progenitor cells and subsequently neurons and glial cells, which together build up the entire adult brain. The radial glial cells, with their characteristic radial fibers that stretch from the inner ventricular wall to the outer cortex, are known to be the neural stem cells of the neocortex. Migrating neurons use these radial fibers to climb from the proliferative VZ in the inner part of the brain to the outer layers of the cortex, where differentiation processes continue. To establish the complex structures that constitute the adult cerebral cortex, proliferation, migration, and differentiation must be tightly controlled by various signaling events, including cytosolic Ca(2+) signaling. During development, cells regularly exhibit spontaneous Ca(2+) activity that stimulates downstream effectors, which can elicit these fundamental cell processes. Spontaneous Ca(2+) activity during early neocortical development depends heavily on gap junctions and voltage dependent Ca(2+) channels, whereas later in development neurotransmitters and synapses exert an influence. Here, we provide an overview of the literature on Ca(2+) signaling and its impact on cell proliferation, migration, and differentiation in the neocortex. We point out important historical studies and review recent progress in determining the role of Ca(2+) signaling in neocortical development.

  10. [Renal calcium excretion and urolithiasis].

    PubMed

    Aruga, Seiji; Honma, Yukio

    2011-10-01

    Patients with urolithiasis have been increasing in the world, especially morbidity of calcium nephrolithiasis has been increasing in the advanced countries. The changes in the environmental factors including alternation of diet are said to be associated with the increment of morbidity of kidney stone. Idiopathic hypercalciuria is one of the most important risk factor of calcium nephrolithiasis and is classified into absorptive, resorptive, and renal leak. Though the origins of these three types of hypercalciuria are different, increased bone resorption and increased calcium absorption from gut tend to be observed simultaneously. Not only genetic abnormalities in the proteins which are involved in calcium metabolisms but environmental factors such as high sodium intake and chronic acid load caused by increased ingestion of animal protein have been considered to be associated with increased urinary calcium excretion. Renal metabolisms of oxalate and phosphate which are important compositions of calcium containing stone, uric acid as a promoter and citrate as a inhibitor of nephrolithiasis are also described.

  11. Readiness-potentials preceding unrestricted 'spontaneous' vs. pre-planned voluntary acts.

    PubMed

    Libet, B; Wright, E W; Gleason, C A

    1982-09-01

    The nature of readiness-potentials (RPs) that may be associated with fully endogenous, 'freely' voluntary acts was investigated. Restriction on when to act were eliminated and instructions fostered 'spontaneity.' The 'self-initiated' RPs exhibited in these conditions were categorizable into two (possibly three) types, all of which could be exhibited by the same subject. Type I had an early onset at about -1050 +/- 175 msec and a long ramp-like form, resembling self-paced RPs. In type II the main negative shift began at about -575 +/- 150 msec, and at about -240 +/- 50 msec in type III. Type II partially resembled the similarly timed NS' component in self-paced RPs. For acts produced at known, preset times, in which freedom of choice was eliminated but planning to act was required, RPs resembled self-initiated type I RPs and self-paced RPs. All RPs were maximal at the vertex, especially type II even though it was also bilaterally asymmetrical. These distributions suggest that cortical areas other than area 4 and 6 contribute importantly, especially to type II. All RPs, whether in self-initiated or pre-planned acts, appear related specifically to preparation for a motor action. When task-related skin stimuli replaced self-initiated movements, under similar conditions of attentiveness (and expectancy), there were either no or relatively small event-preceding-slow potential shifts. All post-stimulus P300 waves were very large. Two volitional processes are postulated: process I is associated with development of pre-planning or preparation to act in the near future (seconds), whether voluntary choice is present (type I RPs) or absent (pre-set RPs); process II, with an onset at roughly 0.5 sec before the act, is associated more uniquely with voluntary choice and with the more specific as well as endogenous urge or intention to act; it can be present in the comparative absence of or in sequence and overlapping with process I.

  12. Local seismicity preceding the March 14, 1979, Petatlan, Mexico Earthquake (Ms = 7.6)

    NASA Astrophysics Data System (ADS)

    Hsu, Vindell; Gettrust, Joseph F.; Helsley, Charles E.; Berg, Eduard

    1983-05-01

    Local seismicity surrounding the epicenter of the March 14, 1979, Petatlan, Mexico earthquake was monitored by a network of portable seismographs of the Hawaii Institute of Geophysics from 6 weeks before to 4 weeks after the main shock. Prior to the main shock, the recorded local seismic activity was shallow and restricted within the continental plate above the Benioff zone. The relocated main shock hypocenter also lay above the Benioff zone, suggesting an initial failure within the continental lithosphere. Four zones can be recognized that showed relatively higher seismic activity than the background. Activity within these zones has followed a number of moderate earthquakes that occurred before or after the initial deployment of the network. Three of these moderate earthquakes were near the Mexican coastline and occurred sequentially from southeast to northwest during the three months before the Petatlan earthquake. The Petatlan event occurred along the northwestern extension of this trend. We infer a possible connection between this observed earthquake migration pattern and the subduction of a fracture zone because the 200-km segment that includes the aftershock zones of the Petatlan earthquake and the three preceding moderate earthquakes matches the intersection of the southeastern limb of the Orozco Fracture Zone and the Middle America Trench. The Petatlan earthquake source region includes the region of the last of the three near-coast seismic activities (zone A). Earthquakes of zone A migrated toward the Petatlan main shock epicenter and were separated from it by an aseismic zone about 10 km wide. We designate this group of earthquakes as the foreshocks of the Petatlan earthquake. These foreshocks occurred within the continental lithosphere and their observed characteristics are interpreted as due to the high-stress environment before the main shock. Pre-main shock seismicity of the Petatlan earthquake source region shows a good correlation with the

  13. Predictive Physiological Anticipation Preceding Seemingly Unpredictable Stimuli: A Meta-Analysis

    PubMed Central

    Mossbridge, Julia; Tressoldi, Patrizio; Utts, Jessica

    2012-01-01

    This meta-analysis of 26 reports published between 1978 and 2010 tests an unusual hypothesis: for stimuli of two or more types that are presented in an order designed to be unpredictable and that produce different post-stimulus physiological activity, the direction of pre-stimulus physiological activity reflects the direction of post-stimulus physiological activity, resulting in an unexplained anticipatory effect. The reports we examined used one of two paradigms: (1) randomly ordered presentations of arousing vs. neutral stimuli, or (2) guessing tasks with feedback (correct vs. incorrect). Dependent variables included: electrodermal activity, heart rate, blood volume, pupil dilation, electroencephalographic activity, and blood oxygenation level dependent (BOLD) activity. To avoid including data hand-picked from multiple different analyses, no post hoc experiments were considered. The results reveal a significant overall effect with a small effect size [fixed effect: overall ES = 0.21, 95% CI = 0.15–0.27, z = 6.9, p < 2.7 × 10−12; random effects: overall (weighted) ES = 0.21, 95% CI = 0.13–0.29, z = 5.3, p < 5.7 × 10−8]. Higher quality experiments produced a quantitatively larger effect size and a greater level of significance than lower quality studies. The number of contrary unpublished reports that would be necessary to reduce the level of significance to chance (p > 0.05) was conservatively calculated to be 87 reports. We explore alternative explanations and examine the potential linkage between this unexplained anticipatory activity and other results demonstrating meaningful pre-stimulus activity preceding behaviorally relevant events. We conclude that to further examine this currently unexplained anticipatory activity, multiple replications arising from different laboratories using the same methods are necessary. The cause of this anticipatory activity, which undoubtedly lies within the realm of natural

  14. EBCT measured coronary artery calcium scores in asymptomatic life insurance applicants.

    PubMed

    Zamarripa, Daniel; Stanger, Harry

    2006-01-01

    EBCT measured coronary calcium is fast becoming a standard screening tool in asymptomatic patients with and without risk factors who apply for life insurance. Since atherosclerotic plaques become calcified as part of their natural history, the calcium score is an excellent measure of total atherosclerotic burden. Over the past 5 years, various clinical studies have confirmed the predictive value of the coronary calcium score for both soft (revascularization, MI) and hard (MI and sudden cardiac death) events incrementally and independently of traditional coronary risk factors identified by the Framingham Heart Study. Accurate assessment of cardiac mortality risk in asymptomatic applicants for life insurance should include both traditional risk factor assessments in combination with age and gender specific percentiles for coronary calcium. New data from both new and ongoing clinical trials will seek to further support the predictive value of coronary calcium scores as an independent and incremental predictor of hard cardiac events. PMID:17323758

  15. Dissociable Neural Effects of Stimulus Valence and Preceding Context during the Inhibition of Responses to Emotional Faces

    PubMed Central

    Schulz, Kurt P.; Clerkin, Suzanne M.; Halperin, Jeffrey M.; Newcorn, Jeffrey H.; Tang, Cheuk Y.; Fan, Jin

    2009-01-01

    Socially appropriate behavior requires the concurrent inhibition of actions that are inappropriate in the context. This self-regulatory function requires an interaction of inhibitory and emotional processes that recruits brain regions beyond those engaged by either process alone. In this study, we isolated brain activity associated with response inhibition and emotional processing in 24 healthy adults using event-related functional magnetic resonance imaging (fMRI) and a go/no-go task that independently manipulated the context preceding no-go trials (i.e., number of go trials) and the valence (i.e., happy, sad, and neutral) of the face stimuli used as trial cues. Parallel quadratic trends were seen in correct inhibitions on no-go trials preceded by increasing numbers of go trials and associated activation for correct no-go trials in inferior frontal gyrus pars opercularis, pars triangularis, and pars orbitalis, temporoparietal junction, superior parietal lobule, and temporal sensory association cortices. Conversely, the comparison of happy versus neutral faces and sad versus neutral faces revealed valence-dependent activation in the amygdala, anterior insula cortex, and posterior midcingulate cortex. Further, an interaction between inhibition and emotion was seen in valence-dependent variations in the quadratic trend in no-go activation in the right inferior frontal gyrus and left posterior insula cortex. These results suggest that the inhibition of response to emotional cues involves the interaction of partly dissociable limbic and frontoparietal networks that encode emotional cues and use these cues to exert inhibitory control over the motor, attention, and sensory functions needed to perform the task, respectively. PMID:19086020

  16. Calcium Kinetics During Space Flight

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; Wastney, Meryl E.; OBrien, Kimberly O.; Lane, Helen W.

    1999-01-01

    Bone loss is one of the most detrimental effects of space flight, threatening to limit the duration of human space missions. The ability to understand and counteract this loss will be critical for crew health and safety during and after extended-duration missions. The hypotheses to be tested in this project are that space flight alters calcium homeostasis and bone mineral metabolism, and that calcium homeostasis and bone mineral metabolism will return to baseline within days to weeks of return to Earth. These hypotheses will be evidenced by elevated rates of bone mineral resorption and decreased bone mineral deposition, decreased absorption of dietary calcium, altered calcitropic endocrine profiles, elevated excretion of calcium in urine and feces, and elevated excretion of markers of bone resorption. The second hypothesis will be evidenced by return of indices of calcium homeostasis and bone metabolism to preflight levels within days to weeks of return to Earth. Studies will be conducted on International Space Station astronauts before, during, and after extended-duration flights. Measurements of calcium kinetics, bone mass, and endocrine/biochemical markers of bone and calcium homeostasis will be conducted. Kinetic studies utilizing dual isotope tracer kinetic studies and mathematical modeling techniques will allow for determination of bone calcium deposition, bone calcium resorption, dietary calcium absorption and calcium excretion (both urinary and endogenous fecal excretion). These studies will build upon preliminary work conducted on the Russian Mir space station. The results from this project will be critical for clarifying how microgravity affects bone and calcium homeostasis, and will provide an important control point for assessment of countermeasure efficacy. These results are expected to aid in developing countermeasures for bone loss, both for space crews and for individuals on Earth who have metabolic bone diseases.

  17. Intracellular calcium puffs in osteoclasts.

    PubMed

    Radding, W; Jordan, S E; Hester, R B; Blair, H C

    1999-12-15

    We studied intracellular calcium ([Ca(2+)](i)) in acid-secreting bone-attached osteoclasts, which produce a high-calcium acidic extracellular compartment. Acid secretion and [Ca(2+)](i) were followed using H(+)-restricted dyes and fura-2 or fluo-3. Whole cell calcium of acid-secreting osteoclasts was approximately 100 nM, similar to cells on inert substrate that do not secrete acid. However, measurements in restricted areas of the cell showed [Ca(2+)](i) transients to 500-1000 nM consistent with calcium puffs, transient (millisecond) localized calcium elevations reported in other cells. Spot measurements at 50-ms intervals indicated that puffs were typically less than 400 ms. Transients did not propagate in waves across the cell in scanning confocal measurements. Calcium puffs occurred mainly over regions of acid secretion as determined using lysotracker red DND99 and occurred at irregular periods averaging 5-15 s in acid secreting cells, but were rare in lysotracker-negative nonsecretory cells. The calmodulin antagonist trifluoperazine, cell-surface calcium transport inhibitors lanthanum or barium, and the endoplasmic reticulum ATPase inhibitor thapsigargin had variable acute effects on the mean [Ca(2+)](i) and puff frequency. However, none of these agents prevented calcium puff activity, suggesting that the mechanism producing the puffs is independent of these processes. We conclude that [Ca(2+)](i) transients in osteoclasts are increased in acid-secreting osteoclasts, and that the puffs occur mainly near the acid-transporting membrane. Cell membrane acid transport requires calcium, suggesting that calcium puffs function to maintain acid secretion. However, membrane H(+)-ATPase activity was insensitive to calcium in the 100 nM-1 microM range. Thus, any effects of calcium puffs on osteoclastic acid transport must be indirect.

  18. Life events in health care providers before and during Persian Gulf War deployment: the USNS Comfort.

    PubMed

    Slusarcick, A L; Ursano, R J; Fullerton, C S; Dinneen, M P

    1999-10-01

    Just before the onset of Operation Desert Storm, health care personnel (N = 250) onboard the USNS Comfort reported the occurrence of life events for the preceding year, including before deployment and during the Persian Gulf War. Study participants noted both total and negative life events. The mean number of negative life events during the preceding year was 1.44; a sizable proportion of participants (38%) reported no negative life events during this time. There were no differences in the mean number of total or negative life events by gender, although women checked significantly more life event items related to interpersonal factors and men noted more life events concerning financial issues. Women, nurses, the childless, and lower ranking officers noted significantly greater negative life events during predeployment than deployment. Negative life events were moderately related to anxiety, depression, and post-traumatic stress disorder symptoms. Both research and policy implications are discussed.

  19. Apoplastic calcium executes a shut-down function on plant peroxidases

    PubMed Central

    Plieth, Christoph

    2012-01-01

    Recently it was demonstrated that PO activity is switched by calcium within the typical range of apoplastic free calcium concentrations (Plieth and Vollbehr, Plant Signal Behav 2012;7: 650–660). The heat stability of POs is also dependent on calcium. Here, a scenario is put forward which assigns calcium a switch-off function under heat: Peroxidases are switched off by heat stress-triggered apoplastic calcium depletion. It is assumed that this initiates apoplastic accumulation of reactive oxygen species (ROS) and eventually triggers a self-amplifying cascade of cellular events involving plasma membrane ion transport. Calcium depletion-initiated ROS accumulation (CaDIRA) may also trigger signal percolation and the formation of systemic responses to many different stress factors in plants. This hypothesis can explain some as yet unexplained observations. PMID:22580701

  20. Calcium titration of Chlamydomonas reinhardtii centrin and its structural changes

    NASA Astrophysics Data System (ADS)

    Ocaña, Wanda; Pastrana-Ríos, Belinda

    2014-07-01

    Chlamydomonas reinhardtii centrin is a highly conserved calcium binding protein belonging to the EF-hand superfamily. Centrin, like other calcium binding proteins, changes conformation upon calcium binding. In addition, the calcium binding sites are comprised mainly of aspartates and glutamates which would serve as probes for a calcium binding event. 2D IR correlation spectroscopy has proven to be a valuable technique to determine the differences in the molecular behavior of the EF-hand domains within centrin. Moreover, the differences in affinity for calcium displayed by these domains were correlated to differences in the molecular behavior of these EF-hand domains when compared with each other and the full-length protein. We were able to confirm the nature of the two independent domains within centrin. Furthermore, we established the mechanism of aggregation was self-association due to adsorption of centrin to the ZnSe ATR crystal and estimated the extent of aggregation of the full-length protein.

  1. A novel car following model considering average speed of preceding vehicles group

    NASA Astrophysics Data System (ADS)

    Sun, Dihua; Kang, Yirong; Yang, Shuhong

    2015-10-01

    In this paper, a new car following model is presented by considering the average speed effect of preceding vehicles group in cyber-physical systems (CPS) environment. The effect of this new consideration upon the stability of traffic flow is examined through linear stability analysis. A modified Korteweg-de Vries (mKdV) equation was derived via nonlinear analysis to describe the propagating behavior of traffic density wave near the critical point. Good agreement between the simulation and the analytical results shows that average speed of preceding vehicles group leads to the stabilization of traffic systems, and thus can efficiently suppress the emergence of traffic jamming.

  2. Progress through precedent: Going where no helicopter simulator has gone before

    NASA Technical Reports Server (NTRS)

    Adams, Richard J.

    1992-01-01

    Helicopter simulators have been approved by means of special exemption; there are no FAA standards for simulators used in training or airmen Certification checking. The fixed-wing industry provides a precedent which can be used for expediting implementation of helicopter simulators. The analysis in this paper is founded on the experience with that precedent and is driven by a clear definition of helicopter user needs for (1) improved training at lower cost, (2) more comprehensive emergency training at lower risk, (3) increased fidelity of transition and instrument training compared with low-cost aircraft alternatives, and (4) certification credit for improved simulator training.

  3. Relationship Type and Sexual Precedence: Their Associations With Characteristics of Sexual Assault Perpetrators and Incidents

    PubMed Central

    Wegner, Rhiana; Pierce, Jennifer; Abbey, Antonia

    2015-01-01

    Although most sexual assaults are committed by men who know their victims, few researchers have considered how characteristics of perpetrators and incidents differ depending on the victim–perpetrator relationship. This study addresses this gap with a community sample of 204 men who reported committing a sexually aggressive act in an audio computer-assisted self-interview. 2 (Relationship Type: Committed vs. Casual) × 2 (Sexual Precedence: Yes vs. No) ANOVAs revealed significant main effects of relationship type and sexual precedence associated with individual difference and incident characteristics. These findings demonstrate the importance of developing theories and prevention programs tailored for different relationship contexts. PMID:25288595

  4. Aberrant subcellular neuronal calcium regulation in aging and Alzheimer's disease.

    PubMed

    Camandola, Simonetta; Mattson, Mark P

    2011-05-01

    In this mini-review/opinion article we describe evidence that multiple cellular and molecular alterations in Alzheimer's disease (AD) pathogenesis involve perturbed cellular calcium regulation, and that alterations in synaptic calcium handling may be early and pivotal events in the disease process. With advancing age neurons encounter increased oxidative stress and impaired energy metabolism, which compromise the function of proteins that control membrane excitability and subcellular calcium dynamics. Altered proteolytic cleavage of the β-amyloid precursor protein (APP) in response to the aging process in combination with genetic and environmental factors results in the production and accumulation of neurotoxic forms of amyloid β-peptide (Aβ). Aβ undergoes a self-aggregation process and concomitantly generates reactive oxygen species that can trigger membrane-associated oxidative stress which, in turn, impairs the functions of ion-motive ATPases and glutamate and glucose transporters thereby rendering neurons vulnerable to excitotoxicity and apoptosis. Mutations in presenilin-1 that cause early-onset AD increase Aβ production, but also result in an abnormal increase in the size of endoplasmic reticulum calcium stores. Some of the events in the neurodegenerative cascade can be counteracted in animal models by manipulations that stabilize neuronal calcium homeostasis including dietary energy restriction, agonists of glucagon-like peptide 1 receptors and drugs that activate mitochondrial potassium channels. Emerging knowledge of the actions of calcium upstream and downstream of Aβ provides opportunities to develop novel preventative and therapeutic interventions for AD. This article is part of a Special Issue entitled: 11th European Symposium on Calcium. PMID:20950656

  5. The Role of a Coronary Artery Calcium Scan in Type 1 Diabetes.

    PubMed

    Burge, Mark R; Eaton, R Philip; Schade, David S

    2016-09-01

    The coronary artery calcium (CAC) scan has recently emerged as a reproducible noninvasive test to detect asymptomatic atherosclerotic coronary artery disease. It has several advantages over the traditional cardiac stress testing modalities, including lower cost, greater sensitivity for nonobstructing coronary artery lesions, and excellent prognostic value when combined with the Framingham risk parameters. Its chief disadvantage is that it does not identify obstructing coronary artery lesions or noncalcified coronary artery plaque. A CAC scan utilizes a chest computed tomogram and computer software to calculate the amount of calcium in the four main coronary vessels. Calcium is deposited in coronary plaques so that the greater the calcium score, the greater the plaque burden. This, in turn, is the basis for predicting a 10-15-year risk of a cardiovascular event. Individuals with a zero calcium score have a very low 10-year risk of a cardiovascular event. Obtaining a calcium score in a diabetic patient permits rational decisions for prescribing statin therapy. In patients with a zero score, the initiation of statin therapy is not recommended because the 5-year incidence of atherosclerotic cardiovascular disease is so low. In patients with diabetes, it is recommended to repeat the calcium scan in 4-5 years to permit timely therapy in the event that the score becomes positive. Since statins mildly increase coronary calcium as part of the stabilization of plaque, a reduction in the calcium score should not be anticipated. However, progression of the calcium score by more than 15%/year (calculated from a repeat CAC scan) provides additional prognostic information of an indication of progression of atherosclerosis. In summary, the coronary calcium score is a major clinical advance for noninvasively detecting coronary artery disease and managing antiatherosclerotic therapy in type 1 diabetes. PMID:27585206

  6. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Calcium alginate is prepared...

  7. Artemisinin Induces Calcium-Dependent Protein Secretion in the Protozoan Parasite Toxoplasma gondii▿ †

    PubMed Central

    Nagamune, Kisaburo; Beatty, Wandy L.; Sibley, L. David

    2007-01-01

    Intracellular calcium controls several crucial cellular events in apicomplexan parasites, including protein secretion, motility, and invasion into and egress from host cells. The plant compound thapsigargin inhibits the sarcoplasmic-endoplasmic reticulum calcium ATPase (SERCA), resulting in elevated calcium and induction of protein secretion in Toxoplasma gondii. Artemisinins are natural products that show potent and selective activity against parasites, making them useful for the treatment of malaria. While the mechanism of action is uncertain, previous studies have suggested that artemisinin may inhibit SERCA, thus disrupting calcium homeostasis. We cloned the single-copy gene encoding SERCA in T. gondii (TgSERCA) and demonstrate that the protein localizes to the endoplasmic reticulum in the parasite. In extracellular parasites, TgSERCA partially relocalized to the apical pole, a highly active site for regulated secretion of micronemes. TgSERCA complemented a calcium ATPase-defective yeast mutant, and this activity was inhibited by either thapsigargin or artemisinin. Treatment of T. gondii with artemisinin triggered calcium-dependent secretion of microneme proteins, similar to the SERCA inhibitor thapsigargin. Artemisinin treatment also altered intracellular calcium in parasites by increasing the periodicity of calcium oscillations and inducing recurrent, strong calcium spikes, as imaged using Fluo-4 labeling. Collectively, these results demonstrate that artemisinin perturbs calcium homeostasis in T. gondii, supporting the idea that Ca2+-ATPases are potential drug targets in parasites. PMID:17766463

  8. Learning from Mount St. Helens: Catastrophic Events as Educational Opportunities.

    ERIC Educational Resources Information Center

    Anderson, Jeremy

    1987-01-01

    Maintains that the study of catastrophic events should be given temporary precedence over the normal curriculum in order to help students understand the causes, consequences, and recovery alternatives, deal with trauma, and allay fear of recurrence and feelings of helplessness. Uses the May 1980 eruption of Mount St. Helens to demonstrate how…

  9. Effects of photoreleased cADP-ribose on calcium transients and calcium sparks in myocytes isolated from guinea-pig and rat ventricle.

    PubMed Central

    Cui, Y; Galione, A; Terrar, D A

    1999-01-01

    Actions of photoreleased cADP-ribose (cADPR), a novel regulator of calcium-induced calcium release (CICR) from ryanodine-sensitive stores, were investigated in cardiac myocytes. Photoreleased cADPR caused an increase in the magnitude of whole-cell calcium transients studied in mammalian cardiac ventricular myocytes (both guinea-pig and rat) using confocal microscopy). Approx. 15 s was required following photorelease of cADPR for the development of its maximal effect. Photoreleased cADPR also increased the frequency of calcium 'sparks', which are thought to be elementary events which make up the whole-cell calcium transient, and were studied in rat myocytes, but had little or no effect on spark characteristics (amplitude, rise time, decay time and distance to half amplitude). The potentiating effects of photoreleased cADPR on both whole-cell transients and the frequency of calcium sparks were prevented by cytosolic application of the antagonist 8-amino-cADPR (5 microM). These experiments, therefore, provide the first evidence in any cell type for an effect of cADPR on calcium sparks, and are the first to show the actions of photoreleased cADPR on whole-cell calcium transients in mammalian cells. The observations are consistent with the effects of cADPR in enhancing the calcium sensitivity of CICR from the sarcoplasmic reticulum in cardiac ventricular myocytes, leading to an increase in the probability of occurrence of calcium sparks and to an increase in whole-cell calcium transients. The slow time-course for development of the full effect on whole-cell calcium transients might be taken to indicate that the influence of cADPR on CICR may involve complex molecular interactions rather than a simple direct action of cADPR on the ryanodine-receptor channels. PMID:10455010

  10. Calcium distribution in aortic smooth muscle cells of deoxycorticosterone-hypertensive rats. A quantitative cytochemical study.

    PubMed

    Nickerson, P A; Yang, F

    1988-04-01

    The effect of deoxycorticosterone (DOC)-induced hypertension on the calcium content within the aorta was studied before the increase in pressure (one week) and after the pressure had reached hypertensive levels (4 weeks). The volume density of free calcium detected ultrastructurally by pyroantimonate precipitation was quantitated by stereological techniques in aortic smooth muscle cells. An increase in the volume density of electron opaque precipitate was observed in the cytoplasm at one week of DOC treatment when neither the systolic blood pressure, the thickness of the media nor volume fraction of medial smooth muscle as compared to the extracellular space was increased significantly. The total aortic calcium as measured by atomic absorption spectroscopy was not increased at one week. By 4 weeks when the rats were hypertensive, the cytoplasmic free calcium in the smooth muscle cells and the number of peripherally-located cytoplasmic vesicles with precipitate was increased significantly. Total aortic calcium was also increased significantly in the DOC-saline group but not in the DOC group drinking tap water or in the saline drinking controls. An elevation of calcium within the cytoplasm of vascular smooth muscle cells may precede the development of hypertension and play a role in the pathogenesis of the increased blood pressure, increased medial thickness and hypertrophy of the vascular smooth muscle cells.

  11. The role of calcium hydroxylapatite (Radiesse) in nonsurgical aesthetic rejuvenation.

    PubMed

    Lizzul, Paul F; Narurkar, Vic A

    2010-05-01

    Radiesse (Bioform Medical, San Mateo, CA) is a synthetic calcium hydroxylapatite microsphere filler suspended in an aqueous carrier gel. Radiesse currently has indications in the United States (U.S.) for the correction of signs of lipoatrophy in individuals with human immunodeficiency virus (HIV) as well as for the correction of moderate-to-deep nasolabial folds. There are also numerous off label reports in the literature of use in other facial aesthetic procedures. This review describes the composition of calcium hydroxylapatite, its mechanism of action, durability and safety, pre- and post-procedure care, injection techniques, appropriate use, concomitant anesthesia, as well as potential adverse events and complications.

  12. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium pantothenate, calcium chloride double salt..., calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may... information required by the Act, the following: (1) The name of the additive “calcium chloride double salt...

  13. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium pantothenate, calcium chloride double salt... Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may be safely used in foods for...

  14. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium pantothenate, calcium chloride double salt..., calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may... information required by the Act, the following: (1) The name of the additive “calcium chloride double salt...

  15. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium pantothenate, calcium chloride double salt..., calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may... information required by the Act, the following: (1) The name of the additive “calcium chloride double salt...

  16. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium pantothenate, calcium chloride double salt..., calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may... information required by the Act, the following: (1) The name of the additive “calcium chloride double salt...

  17. Coronary artery calcium score: has anything changed?

    PubMed

    Marano, R; Bonomo, L

    2007-10-01

    Calcium deposition along the coronary artery walls is a surrogate biomarker for atherosclerosis, and its presence in the coronary arteries could reflect the severity of coronary artery disease (CAD) High coronary artery calcium score (CACS) correlates with advanced disease and a higher likelihood of coronary stenoses. Many studies have supported the role of CACS as a screening tool for CAD. Historically, CACS was introduced with electron beam computed tomography (EBCT), but in the last 30 years, many changes have occurred in CT, where the development of multidetector spiral technology has made reliable the noninvasive study of the heart and coronary arteries. Correlation studies with intravascular ultrasound (IVUS) and histology have demonstrated the capability of multidetector CT (MDCT) to provide information useful for characterising atherosclerotic plaque in a noninvasive manner. This has shifted the interest from heavily calcified deposits to plaque with a low-density core and small, superficial calcified nodules, features more frequently present in atherosclerotic plaque prone to rupture and responsible for acute coronary events (culprit lesions). The purpose of this review article is to summarise the recent evolution and revolution in the field of CT, strengthen the importance of a coronary CT study not limited to CACS evaluation and CAD grading but also used to obtain information about plaque composition, and to improve stratification of the patient at risk for acute coronary events. PMID:17952374

  18. Postwar Era Precedents and the Ambivalent Quest for International Students at the University of Florida

    ERIC Educational Resources Information Center

    Terzian, Sevan G.; Osborne, Leigh Ann

    2006-01-01

    The number of international students studying at U.S. institutions of higher education in the 2003-2004 academic year dropped for the first time in more than three decades. New visa restrictions and international tensions in the wake of September 11, 2001, have been cited as central factors. This article identifies historical precedents from the…

  19. Effect of Personnel Change on Supreme Court Use of Precedent in Freedom of Expression Cases.

    ERIC Educational Resources Information Center

    Schwartz, Thomas A.; Warrick, Kathleen

    To test the findings of a 1981 study, which concluded that the Supreme Court of Chief Justice Warren Burger has attempted to reverse the liberal policies of the court presided over by Earl Warren by adopting a policy of ignoring precedent, a second study duplicated the earlier study's general research design, except that it focused on freedom of…

  20. Building ensemble representations: How the shape of preceding distractor distributions affects visual search.

    PubMed

    Chetverikov, Andrey; Campana, Gianluca; Kristjánsson, Árni

    2016-08-01

    Perception allows us to extract information about regularities in the environment. Observers can quickly determine summary statistics of a group of objects and detect outliers. The existing body of research has, however, not revealed how such ensemble representations develop over time. Moreover, the correspondence between the physical distribution of features in the external world and their potential internal representation as a probability density function (PDF) by the visual system is still unknown. Here, for the first time we demonstrate that such internal PDFs are built during visual search and show how they can be assessed with repetition and role-reversal effects. Using singleton search for an oddly oriented target line among differently oriented distractors (a priming of pop-out paradigm), we test how different properties of previously observed distractor distributions (mean, variability, and shape) influence search times. Our results indicate that observers learn properties of distractor distributions over and above mean and variance; in fact, response times also depend on the shape of the preceding distractor distribution. Response times decrease as a function of target distance from the mean of preceding Gaussian distractor distributions, and the decrease is steeper when preceding distributions have small standard deviations. When preceding distributions are uniform, however, this decrease in response times can be described by a two-piece function corresponding to the uniform distribution PDF. Moreover, following skewed distributions response times function is skewed in accordance with the skew in distributions. Indeed, internal PDFs seem to be specifically tuned to the observed feature distribution. PMID:27232163

  1. Applying PRECEDE-PROCEED to Develop an Intuitive Eating Nondieting Approach to Weight Management Pilot Program

    ERIC Educational Resources Information Center

    Cole, Renee E.; Horacek, Tanya

    2009-01-01

    Objective: To describe the use of a consolidated version of the PRECEDE-PROCEED participatory program planning model to collaboratively design an intuitive eating program with Fort Drum military spouses tailored to their readiness to reject the dieting mentality and make healthful lifestyle modifications. Design: A consolidated version of…

  2. Building ensemble representations: How the shape of preceding distractor distributions affects visual search.

    PubMed

    Chetverikov, Andrey; Campana, Gianluca; Kristjánsson, Árni

    2016-08-01

    Perception allows us to extract information about regularities in the environment. Observers can quickly determine summary statistics of a group of objects and detect outliers. The existing body of research has, however, not revealed how such ensemble representations develop over time. Moreover, the correspondence between the physical distribution of features in the external world and their potential internal representation as a probability density function (PDF) by the visual system is still unknown. Here, for the first time we demonstrate that such internal PDFs are built during visual search and show how they can be assessed with repetition and role-reversal effects. Using singleton search for an oddly oriented target line among differently oriented distractors (a priming of pop-out paradigm), we test how different properties of previously observed distractor distributions (mean, variability, and shape) influence search times. Our results indicate that observers learn properties of distractor distributions over and above mean and variance; in fact, response times also depend on the shape of the preceding distractor distribution. Response times decrease as a function of target distance from the mean of preceding Gaussian distractor distributions, and the decrease is steeper when preceding distributions have small standard deviations. When preceding distributions are uniform, however, this decrease in response times can be described by a two-piece function corresponding to the uniform distribution PDF. Moreover, following skewed distributions response times function is skewed in accordance with the skew in distributions. Indeed, internal PDFs seem to be specifically tuned to the observed feature distribution.

  3. Effects of Age and Hearing Loss on Gap Detection and the Precedence Effect: Broadband Stimuli

    ERIC Educational Resources Information Center

    Roberts, Richard A.; Lister, Jennifer J.

    2004-01-01

    Older listeners with normal-hearing sensitivity and impaired-hearing sensitivity often demonstrate poorer-than-normal performance on tasks of speech understanding in noise and reverberation. Deficits in temporal resolution and in the precedence effect may underlie this difficulty. Temporal resolution is often studied by means of a gap-detection…

  4. 29 CFR 548.306 - Average earnings for year or quarter year preceding the current quarter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Average earnings for year or quarter year preceding the... PAY Interpretations Authorized Basic Rates § 548.306 Average earnings for year or quarter year... hour for each workweek equal to the average hourly remuneration of the employee for employment...

  5. Female Genital Cutting: Applying the PRECEDE-PROCEED Model To Understand the Incentives for the Practice.

    ERIC Educational Resources Information Center

    Dabbagh, Leila

    2002-01-01

    Reviews the practice of female circumcision and the significance of considering social, cultural, economic, and educational opportunities available to females in developing countries when creating intervention programs to help end this practice. The PRECEDE-PROCEED model is a tool that can assess various elements present in a girls' life that…

  6. Metabolic and Signaling Alterations in Dystrophin-Deficient Hearts Precede Overt Cardiomyopathy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The cytoskeletal protein dystrophin has been implicated in hereditary and acquired forms of cardiomyopathy. However, much remains to be learned about the role of dystrophin in the heart. We hypothesized that the dystrophin-deficient heart displays early alterations in energy metabolism that precede ...

  7. Using the PRECEDE Model for Causal Analysis of Bulimic Tendencies among Elite Women Swimmers.

    ERIC Educational Resources Information Center

    Benson, RoseAnn; Taub, Diane E.

    1993-01-01

    Describes a study of weight control techniques and bulimic tendencies among elite female participants in an Olympic Swimming Selection Meet. Results showed concern with thinness, body dissatisfaction, and unhealthy eating, dieting, and weight loss patterns among participants. Discusses the explanatory power of the PRECEDE model. (SM)

  8. Ancient Uses of Meteoritic Metals as Precedent for Modern In-Situ Asteroid Mining

    NASA Astrophysics Data System (ADS)

    Mardon, Austin A.; Fawcett, Brett; Krispin, Daniel

    2016-05-01

    Given the strain on earth's supply of metal and the meteoritic content of meteorites, a prudent course would be to pursue in-situ asteroid mining of meteors for metal. There is a precedent for this going back to ancient Egypt; humans have always used the meteoritic content of meteorites to fashion everything from weapons to cosmetics.

  9. 5 CFR 870.801 - Order of precedence and payment of benefits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... specific person or persons to receive life insurance benefits upon the death of an insured individual... the individual(s) entitled to receive Basic life insurance benefits under the statutory order of... SERVICE REGULATIONS (CONTINUED) FEDERAL EMPLOYEES' GROUP LIFE INSURANCE PROGRAM Order of Precedence...

  10. 29 CFR 548.306 - Average earnings for year or quarter year preceding the current quarter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Average earnings for year or quarter year preceding the current quarter. 548.306 Section 548.306 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR REGULATIONS AUTHORIZATION OF ESTABLISHED BASIC RATES FOR COMPUTING OVERTIME PAY Interpretations Authorized Basic Rates...

  11. Reduced Activation of Left Orbitofrontal Cortex Precedes Blocked Vocalization: A Magnetoencephalographic Study

    ERIC Educational Resources Information Center

    Sowman, Paul F.; Crain, Stephen; Harrison, Elisabeth; Johnson, Blake W.

    2012-01-01

    While stuttering is known to be characterized by anomalous brain activations during speech, very little data is available describing brain activations during stuttering. To our knowledge there are no reports describing brain activations that precede blocking. In this case report we present magnetoencephalographic data from a person who stutters…

  12. Strategy Precedes Operational Effectiveness: Aligning High Graduation Rankings with Competitive Graduation Grade Point Averages

    ERIC Educational Resources Information Center

    Apprey, Maurice; Bassett, Kimberley C.; Preston-Grimes, Patrice; Lewis, Dion W.; Wood, Beverly

    2014-01-01

    Two pivotal and interconnected claims are addressed in this article. First, strategy precedes program effectiveness. Second, graduation rates and rankings are insufficient in any account of academic progress for African American students. In this article, graduation is regarded as the floor and not the ceiling, as it were. The ideal situation in…

  13. 7 CFR 1980.454 - Conditions precedent to issuance of the Loan Note Guarantee.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 14 2012-01-01 2012-01-01 false Conditions precedent to issuance of the Loan Note Guarantee. 1980.454 Section 1980.454 Agriculture Regulations of the Department of Agriculture (Continued... AGENCY, DEPARTMENT OF AGRICULTURE (CONTINUED) PROGRAM REGULATIONS (CONTINUED) GENERAL Business...

  14. 7 CFR 1980.454 - Conditions precedent to issuance of the Loan Note Guarantee.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 14 2010-01-01 2009-01-01 true Conditions precedent to issuance of the Loan Note Guarantee. 1980.454 Section 1980.454 Agriculture Regulations of the Department of Agriculture (Continued... AGENCY, DEPARTMENT OF AGRICULTURE (CONTINUED) PROGRAM REGULATIONS (CONTINUED) GENERAL Business...

  15. 7 CFR 1980.454 - Conditions precedent to issuance of the Loan Note Guarantee.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 14 2013-01-01 2013-01-01 false Conditions precedent to issuance of the Loan Note Guarantee. 1980.454 Section 1980.454 Agriculture Regulations of the Department of Agriculture (Continued... AGENCY, DEPARTMENT OF AGRICULTURE (CONTINUED) PROGRAM REGULATIONS (CONTINUED) GENERAL Business...

  16. 7 CFR 1980.454 - Conditions precedent to issuance of the Loan Note Guarantee.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 14 2011-01-01 2011-01-01 false Conditions precedent to issuance of the Loan Note Guarantee. 1980.454 Section 1980.454 Agriculture Regulations of the Department of Agriculture (Continued... AGENCY, DEPARTMENT OF AGRICULTURE (CONTINUED) PROGRAM REGULATIONS (CONTINUED) GENERAL Business...

  17. 7 CFR 1980.454 - Conditions precedent to issuance of the Loan Note Guarantee.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 14 2014-01-01 2014-01-01 false Conditions precedent to issuance of the Loan Note Guarantee. 1980.454 Section 1980.454 Agriculture Regulations of the Department of Agriculture (Continued... AGENCY, DEPARTMENT OF AGRICULTURE (CONTINUED) PROGRAM REGULATIONS (CONTINUED) GENERAL Business...

  18. The Existentialist Reality of Educational Production Functions (Their Existence Has Preceded Their Essence).

    ERIC Educational Resources Information Center

    Michelson, Stephan

    This publication is a discussion of the concept of an educational production function, a mathematical formulation of the relationship between inputs and outputs in education. A description of how a production function can direct decision making toward economic efficiency precedes a theoretical discussion of the nature of actual estimation. Several…

  19. Parafoveal Processing of Word n + 2 during Reading: Do the Preceding Words Matter?

    ERIC Educational Resources Information Center

    Angele, Bernhard; Rayner, Keith

    2011-01-01

    We used the boundary paradigm (Rayner, 1975) to test two hypotheses that might explain why no conclusive evidence has been found for the existence of n + 2 preprocessing effects. In Experiment 1, we tested whether parafoveal processing of the second word to the right of fixation (n + 2) takes place only when the preceding word (n + 1) is very…

  20. Application of the PRECEDE Model to Understanding Mental Health Promoting Behaviors in Hong Kong

    ERIC Educational Resources Information Center

    Mo, Phoenix K. H.; Mak, Winnie W. S.

    2008-01-01

    The burdens related to mental illness have been increasingly recognized in many countries. Nevertheless, research in positive mental health behaviors remains scarce. This study utilizes the Predisposing, Reinforcing, and Enabling Causes in Education Diagnosis and Evaluation (PRECEDE) model to identify factors associated with mental health…

  1. Vitamin D, Calcium, and Bone Health

    MedlinePlus

    ... Balance › Vitamin D, Calcium, and Bone Health Vitamin D, Calcium, and Bone Health March 2012 Download PDFs ... helps keep your bones strong. Why are vitamin D and calcium important to bone health? Vitamin D ...

  2. Electrochemical cell with calcium anode

    DOEpatents

    Cooper, John F.; Hosmer, Pamela K.; Kelly, Benjamin E.

    1979-01-01

    An electrochemical cell comprising a calcium anode and a suitable cathode in an alkaline electrolyte consisting essentially of an aqueous solution of an hydroxide and a chloride. Specifically disclosed is a mechanically rechargeable calcium/air fuel cell with an aqueous NaOH/NaCl electrolyte.

  3. An Improved Calcium Flame Test.

    ERIC Educational Resources Information Center

    Pearson, Robert S.

    1985-01-01

    Indicates that the true red color of calcium can be obtained (using the procedure described by Sorm and Logowski) if the calcium ion solution is mixed with an equal volume of saturated ammonium bromide solution. Suggestions for flame tests of other elements are also noted. (JN)

  4. Calcium Intake: A Lifelong Proposition.

    ERIC Educational Resources Information Center

    Amschler, Denise H.

    1985-01-01

    This article reviews the current problem of low calcium intake in the United States among all age groups, the role of calcium in the formation and maintenance of bone mass, and major factors influencing absorption. Osteoporosis is discussed, and current recommendations for Recommended Dietary allowance are provided. (Author/MT)

  5. Major Minerals - Calcium, Magnesium, Phosphorus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium, magnesium and phosphorus are essential elements critically important for the function of the musculoskeletal system, including the formation and transduction of energy and the maintenance of healthy bone. The major calcium concern for physically active healthy middle-aged adults is to consu...

  6. Calcium in Plants

    PubMed Central

    WHITE, PHILIP J.; BROADLEY, MARTIN R.

    2003-01-01

    Calcium is an essential plant nutrient. It is required for various structural roles in the cell wall and membranes, it is a counter‐cation for inorganic and organic anions in the vacuole, and the cytosolic Ca2+ concentration ([Ca2+]cyt) is an obligate intracellular messenger coordinating responses to numerous developmental cues and environmental challenges. This article provides an overview of the nutritional requirements of different plants for Ca, and how this impacts on natural flora and the Ca content of crops. It also reviews recent work on (a) the mechanisms of Ca2+ transport across cellular membranes, (b) understanding the origins and specificity of [Ca2+]cyt signals and (c) characterizing the cellular [Ca2+]cyt‐sensors (such as calmodulin, calcineurin B‐like proteins and calcium‐dependent protein kinases) that allow plant cells to respond appropriately to [Ca2+]cyt signals. PMID:12933363

  7. Calcium-sensing receptor and calcium kidney stones.

    PubMed

    Vezzoli, Giuseppe; Terranegra, Annalisa; Rainone, Francesco; Arcidiacono, Teresa; Cozzolino, Mario; Aloia, Andrea; Dogliotti, Elena; Cusi, Daniele; Soldati, Laura

    2011-11-22

    Calcium nephrolithiasis may be considered as a complex disease having multiple pathogenetic mechanisms and characterized by various clinical manifestations. Both genetic and environmental factors may increase susceptibility to calcium stones; therefore, it is crucial to characterize the patient phenotype to distinguish homogeneous groups of stone formers. Family and twin studies have shown that the stone transmission pattern is not mendelian, but complex and polygenic. In these studies, heritability of calcium stones was calculated around 50%Calcium-sensing receptor (CaSR) is mostly expressed in the parathyroid glands and in renal tubules. It regulates the PTH secretion according to the serum calcium concentration. In the kidney, it modulates electrolyte and water excretion regulating the function of different tubular segments. In particular, CaSR reduces passive and active calcium reabsorption in distal tubules, increases phosphate reabsorption in proximal tubules and stimulates proton and water excretion in collecting ducts. Therefore, it is a candidate gene for calcium nephrolithiasis.In a case-control study we found an association between the normocitraturic stone formers and two SNPs of CaSR, located near the promoters region (rs7652589 and rs1501899). This result was replicated in patients with primary hyperparathyroidism, comparing patients with or without kidney stones. Bioinformatic analysis suggested that the minor alleles at these polymorphisms were able to modify the binding sites of specific transcription factors and, consequently, CaSR expression.Our studies suggest that CaSR is one of the candidate genes explaining individual predisposition to calcium nephrolithiasis. Stone formation may be favored by an altered CaSR expression in kidney medulla involving the normal balance among calcium, phosphate, protons and water excretion.

  8. Sensitivity to calcium intake in calcium stone forming patients.

    PubMed

    Heilberg, I P; Martini, L A; Draibe, S A; Ajzen, H; Ramos, O L; Schor, N

    1996-01-01

    The absorptive or renal origin of hypercalciuria can be discriminated using an acute oral calcium load test (ACLT). Of 86 patients with calcium oxalate kidney stones, 28 (23%) were found to be hypercalciuric (HCa) and 58 (67%) normocalciuric (NCa) on their customary free diet, containing 542 +/- 29 mg/day (mean +/- SE) of calcium. Since the apparently normal 24-hour calcium excretion of many calcium stone formers (CSF) may be due to a combination of high calcium absorption with moderately low calcium intake, all patients were investigated by ACLT. Of 28 HCa patients, 13 (46%) were classified as absorptive (AH) and 15 (54%) as renal hypercalciuria (RH). Of the 58 NCa patients, 38 (65%) presented features of intestinal hyperabsorption and were therefore designated as AH-like, and 20 (35%) as RH-like. To further elucidate the role of dietary calcium in these CSF, a chronic calcium load test (CCLT), consisting of 1 g/day of oral Ca for 7 days, was designed. A positive response to the CCLT was considered to occur when urinary calcium (uCa) was > or = 4 mg/ kg/24 h on the 7th day. Among NCa patients, 29% of AH-like subjects responded to the CCLT and 71% did not; 50% of RH-like subjects also responded and 50% did not. In HCa patients, 85% of AH and 67% of RH subjects maintained uCa > or = 4 mg/kg/24 h after the CCLT and 15% of AH and 23% of RH subjects did not. However, a significant additional increase in mean uCa was not observed among HCa patients. All patients were submitted to a second evaluation of fasting calciuria (Ca/Cr). A modification of this parameter was noticed in 89% of RH-like and 78% of RH patients. In conclusion, these data suggest the presence of subpopulations of patients sensitive or not to calcium intake, regardless of whether the acute response to a calcium overload test suggested AH or RH. The CCLT disclosed dietary hypercalciuria in 21/58 (36%) of previously NCa patients. In these NCa patients, the ACLT may be replaced by the CCLT. The distinction

  9. Limestone reaction in calcium aluminate cement–calcium sulfate systems

    SciTech Connect

    Bizzozero, Julien Scrivener, Karen L.

    2015-10-15

    This paper reports a study of ternary blends composed of calcium aluminate cement, calcium sulfate hemihydrate and limestone. Compressive strength tests and hydration kinetics were studied as a function of limestone and calcium sulfate content. The phase evolution and the total porosity were followed and compared to thermodynamic simulation to understand the reactions involved and the effect of limestone on these binders. The reaction of limestone leads to the formation of hemicarboaluminate and monocarboaluminate. Increasing the ratio between sulfate and aluminate decreases the extent of limestone reaction.

  10. Calcium wave propagation by calcium-induced calcium release: an unusual excitable system.

    PubMed

    Sneyd, J; Girard, S; Clapham, D

    1993-03-01

    We discuss in detail the behaviour of a model, proposed by Goldbeter et al. (1990. Proc. natn. Acad. Sci. 87, 1461-1465), for intracellular calcium wave propagation by calcium-induced calcium release, focusing our attention on excitability and the propagation of waves in one spatial dimension. The model with no diffusion behaves like a generic excitable system, and threshold behaviour, excitability and oscillations can be understood within this general framework. However, when diffusion is included, the model no longer behaves like a generic excitable system; the fast and slow variables are not distinct and previous results on excitable systems do not necessarily apply. We consider a piecewise linear simplification of the model, and construct travelling pulse and periodic plane wave solutions to the simplified model. The analogous behaviour in the full model is studied numerically. Goldbeter's model for calcium-induced calcium release is an excitable system of a type not previously studied in detail.

  11. Global precedence, spatial frequency channels, and the statistics of natural images.

    PubMed

    Hughes, H C; Nozawa, G; Kitterle, F

    1996-01-01

    A great deal of evidence suggests that early in processing, retinal images are filtered by parallel, spatial frequency selective channels. We attempt to incorporate this view of early vision with the principle of global precedence, which holds that Gestalt-like processes sensitive to global image configurations tend to dominate local feature processing in human pattern perception. Global precedence is inferred from the pattern of reaction times observed when visual patterns contain multiple cues at different levels of spatial scale. Specifically, it is frequently observed that global processing times are largely unaffected by conflicting local cues, but local processing times are substantially lengthened by conflicting global cues. The asymmetry of these effects suggests the dominant role of global configurations. Since global spatial information is effectively represented by low spatial frequencies, global precedence potentially implies a low frequency dominance. The thesis is that low spatial frequencies tend to be available before information carried by higher frequency bands, producing a coarse-to-fine temporal order in visual spatial perception. It is suggested that a variety of factors contribute to the "prior entry" of low frequency information, including the high contrast gain of the magnocellular pathway, the amplitude spectra typical of natural images, and inhibitory interactions between the parallel frequency-tuned channels. Evidence suggesting a close relationship between global precedence and spatial frequency channels is provided by observations that the essential features of the global precedence effect are obtained using patterns consisting of low and high frequency sinusoids. The hypothesis that these asymmetric interference effects are due to interactions between parallel spatial channels is supported by an analysis of reaction times (RTs), which shows that RTs to redundant low and high frequency cues produce less facilitation than predictions

  12. Calcium metabolism in health and disease.

    PubMed

    Peacock, Munro

    2010-01-01

    This brief review focuses on calcium balance and homeostasis and their relationship to dietary calcium intake and calcium supplementation in healthy subjects and patients with chronic kidney disease and mineral bone disorders (CKD-MBD). Calcium balance refers to the state of the calcium body stores, primarily in bone, which are largely a function of dietary intake, intestinal absorption, renal excretion, and bone remodeling. Bone calcium balance can be positive, neutral, or negative, depending on a number of factors, including growth, aging, and acquired or inherited disorders. Calcium homeostasis refers to the hormonal regulation of serum ionized calcium by parathyroid hormone, 1,25-dihydroxyvitamin D, and serum ionized calcium itself, which together regulate calcium transport at the gut, kidney, and bone. Hypercalcemia and hypocalcemia indicate serious disruption of calcium homeostasis but do not reflect calcium balance on their own. Calcium balance studies have determined the dietary and supplemental calcium requirements needed to optimize bone mass in healthy subjects. However, similar studies are needed in CKD-MBD, which disrupts both calcium balance and homeostasis, because these data in healthy subjects may not be generalizable to this patient group. Importantly, increasing evidence suggests that calcium supplementation may enhance soft tissue calcification and cardiovascular disease in CKD-MBD. Further research is needed to elucidate the risks and mechanisms of soft tissue calcification with calcium supplementation in both healthy subjects and CKD-MBD patients.

  13. Macromolecular recognition directs calcium ions to coccolith mineralization sites.

    PubMed

    Gal, Assaf; Wirth, Richard; Kopka, Joachim; Fratzl, Peter; Faivre, Damien; Scheffel, André

    2016-08-01

    Many organisms form elaborate mineralized structures, constituted of highly organized arrangements of crystals and organic macromolecules. The localization of crystals within these structures is presumably determined by the interaction of nucleating macromolecules with the mineral phase. Here we show that, preceding nucleation, a specific interaction between soluble organic molecules and an organic backbone structure directs mineral components to specific sites. This strategy underlies the formation of coccoliths, which are highly ordered arrangements of calcite crystals produced by marine microalgae. On combining the insoluble organic coccolith scaffold with coccolith-associated soluble macromolecules in vitro, we found a massive accretion of calcium ions at the sites where the crystals form in vivo. The in vitro process exhibits profound similarities to the initial stages of coccolith biogenesis in vivo. PMID:27493186

  14. Macromolecular recognition directs calcium ions to coccolith mineralization sites.

    PubMed

    Gal, Assaf; Wirth, Richard; Kopka, Joachim; Fratzl, Peter; Faivre, Damien; Scheffel, André

    2016-08-01

    Many organisms form elaborate mineralized structures, constituted of highly organized arrangements of crystals and organic macromolecules. The localization of crystals within these structures is presumably determined by the interaction of nucleating macromolecules with the mineral phase. Here we show that, preceding nucleation, a specific interaction between soluble organic molecules and an organic backbone structure directs mineral components to specific sites. This strategy underlies the formation of coccoliths, which are highly ordered arrangements of calcite crystals produced by marine microalgae. On combining the insoluble organic coccolith scaffold with coccolith-associated soluble macromolecules in vitro, we found a massive accretion of calcium ions at the sites where the crystals form in vivo. The in vitro process exhibits profound similarities to the initial stages of coccolith biogenesis in vivo.

  15. Calcium dynamics in astrocyte processes during neurovascular coupling

    PubMed Central

    Otsu, Yo; Couchman, Kiri; Lyons, Declan G; Collot, Mayeul; Agarwal, Amit; Mallet, Jean-Maurice; Pfrieger, Frank W; Bergles, Dwight E; Charpak, Serge

    2015-01-01

    Enhanced neuronal activity in the brain triggers a local increase in blood flow, termed functional hyperemia, via several mechanisms, including calcium (Ca2+) signaling in astrocytes. However, recent in vivo studies have questioned the role of astrocytes in functional hyperemia because of the slow and sparse dynamics of their somatic Ca2+ signals and the absence of glutamate metabotropic receptor 5 in adults. Here, we reexamined their role in neurovascular coupling by selectively expressing a genetically encoded Ca2+ sensor in astrocytes of the olfactory bulb. We show that in anesthetized mice, the physiological activation of olfactory sensory neuron (OSN) terminals reliably triggers Ca2+ increases in astrocyte processes but not in somata. These Ca2+ increases systematically precede the onset of functional hyperemia by 1–2 s, reestablishing astrocytes as potential regulators of neurovascular coupling. PMID:25531572

  16. Events diary

    NASA Astrophysics Data System (ADS)

    2000-01-01

    as Imperial College, the Royal Albert Hall, the Royal College of Art, the Natural History and Science Museums and the Royal Geographical Society. Under the heading `Shaping the future together' BA2000 will explore science, engineering and technology in their wider cultural context. Further information about this event on 6 - 12 September may be obtained from Sandra Koura, BA2000 Festival Manager, British Association for the Advancement of Science, 23 Savile Row, London W1X 2NB (tel: 0171 973 3075, e-mail: sandra.koura@britassoc.org.uk ). Details of the creating SPARKS events may be obtained from creating.sparks@britassoc.org.uk or from the website www.britassoc.org.uk . Other events 3 - 7 July, Porto Alegre, Brazil VII Interamerican conference on physics education: The preparation of physicists and physics teachers in contemporary society. Info: IACPE7@if.ufrgs.br or cabbat1.cnea.gov.ar/iacpe/iacpei.htm 27 August - 1 September, Barcelona, Spain GIREP conference: Physics teacher education beyond 2000. Info: www.blues.uab.es/phyteb/index.html

  17. The influence of oxygen on [NiFe]-hydrogenase cofactor biosynthesis and how ligation of carbon monoxide precedes cyanation.

    PubMed

    Stripp, Sven T; Lindenstrauss, Ute; Granich, Claudia; Sawers, R Gary; Soboh, Basem

    2014-01-01

    The class of [NiFe]-hydrogenases is characterized by a bimetallic cofactor comprising low-spin nickel and iron ions, the latter of which is modified with a single carbon monoxide (CO) and two cyanide (CN-) molecules. Generation of these ligands in vivo requires a complex maturation apparatus in which the HypC-HypD complex acts as a 'construction site' for the Fe-(CN)2CO portion of the cofactor. The order of addition of the CO and CN- ligands determines the ultimate structure and catalytic efficiency of the cofactor; however much debate surrounds the succession of events. Here, we present an FT-IR spectroscopic analysis of HypC-HypD isolated from a hydrogenase-competent wild-type strain of Escherichia coli. In contrast to previously reported samples, HypC-HypD showed spectral contributions indicative of an electron-rich Fe-CO cofactor, at the same time lacking any Fe-CN- signatures. This immature iron site binds external CO and undergoes oxidative damage when in contact with O2. Binding of CO protects the site against loss of spectral features associated with O2 damage. Our findings strongly suggest that CO ligation precedes cyanation in vivo. Furthermore, the results provide a rationale for the deleterious effects of O2 on in vivo cofactor biosynthesis.

  18. Intracellular replication of Staphylococcus aureus in mature phagolysosomes in macrophages precedes host cell death, and bacterial escape and dissemination.

    PubMed

    Flannagan, Ronald S; Heit, Bryan; Heinrichs, David E

    2016-04-01

    The success of Staphylococcus aureus as a pathogen is partly attributable to its ability to thwart host innate immune responses, which includes resisting the antimicrobial functions of phagocytes. Here, we have studied the interaction of methicillin-resistant S. aureus (MRSA) strain USA300 with murine RAW 264.7 and primary human macrophages using molecular imaging and single cell analysis to obtain an unprecedented understanding of the interaction between the macrophage and MRSA. Herein we demonstrate that macrophages fail to control intracellular infection by MRSA USA300 despite trafficking the bacteria into mature phagolysosomes. Using fluorescence-based proliferation assays we also show that intracellular staphylococci proliferate and that replication commences while the bacteria are residing in mature phagolysosomes hours after initial phagocytosis. Finally, live-cell fluorescence video microscopy allowed for unprecedented visual insight into the escape of MRSA from macrophages, demonstrating that the macrophages die through a pathway characterized by membrane blebbing and activation of caspase-3 followed by acquisition of the vital dye propidium iodide. Moreover, cell death precedes the emergence of MRSA from infected macrophages, and these events can be ablated by prolonged exposure of infected phagocytes to gentamicin. PMID:26408990

  19. The Influence of Oxygen on [NiFe]–Hydrogenase Cofactor Biosynthesis and How Ligation of Carbon Monoxide Precedes Cyanation

    PubMed Central

    Stripp, Sven T.; Lindenstrauss, Ute; Granich, Claudia; Sawers, R. Gary; Soboh, Basem

    2014-01-01

    The class of [NiFe]–hydrogenases is characterized by a bimetallic cofactor comprising low–spin nickel and iron ions, the latter of which is modified with a single carbon monoxide (CO) and two cyanide (CN−) molecules. Generation of these ligands in vivo requires a complex maturation apparatus in which the HypC–HypD complex acts as a ‘construction site’ for the Fe–(CN)2CO portion of the cofactor. The order of addition of the CO and CN– ligands determines the ultimate structure and catalytic efficiency of the cofactor; however much debate surrounds the succession of events. Here, we present an FT–IR spectroscopic analysis of HypC–HypD isolated from a hydrogenase–competent wild–type strain of Escherichia coli. In contrast to previously reported samples, HypC–HypD showed spectral contributions indicative of an electron–rich Fe–CO cofactor, at the same time lacking any Fe–CN– signatures. This immature iron site binds external CO and undergoes oxidative damage when in contact with O2. Binding of CO protects the site against loss of spectral features associated with O2 damage. Our findings strongly suggest that CO ligation precedes cyanation in vivo. Furthermore, the results provide a rationale for the deleterious effects of O2 on in vivo cofactor biosynthesis. PMID:25211029

  20. Calcium and vitamin D controversies.

    PubMed

    Silver, David S

    2011-08-01

    Controversies regarding appropriate use of vitamin D and calcium are predominately related to the extraskeletal effects. Calcium and vitamin D are essential for bone health. The concerns regarding calcium and cardiovascular complications are inconclusive at best, and do not warrant a change in our approach to supplementation at this time. A growing body of literature exists suggesting that additional vitamin D may have numerous benefits, although more study needs to be done. Further prospective trials would provide insight into the potential advantages that increased vitamin D supplementation could provide. PMID:22023896

  1. Calcium signals in olfactory neurons.

    PubMed

    Tareilus, E; Noé, J; Breer, H

    1995-11-01

    Laser scanning confocal microscopy in combination with the fluorescent calcium indicators Fluo-3 and Fura-Red was employed to estimate the intracellular concentration of free calcium ions in individual olfactory receptor neurons and to monitor temporal and spatial changes in the Ca(2+)-level upon stimulation. The chemosensory cells responded to odorants with a significant increase in the calcium concentration, preferentially in the dendritic knob. Applying various stimulation paradigma, it was found that in a population of isolated cells, subsets of receptor neurons display distinct patterns of responsiveness. PMID:7488645

  2. Calcium signals in olfactory neurons.

    PubMed

    Tareilus, E; Noé, J; Breer, H

    1995-11-01

    Laser scanning confocal microscopy in combination with the fluorescent calcium indicators Fluo-3 and Fura-Red was employed to estimate the intracellular concentration of free calcium ions in individual olfactory receptor neurons and to monitor temporal and spatial changes in the Ca(2+)-level upon stimulation. The chemosensory cells responded to odorants with a significant increase in the calcium concentration, preferentially in the dendritic knob. Applying various stimulation paradigma, it was found that in a population of isolated cells, subsets of receptor neurons display distinct patterns of responsiveness.

  3. Precipitating Events in Adolescent Suicidal Crises: Exploring Stress-Reactive and Nonreactive Risk Profiles

    ERIC Educational Resources Information Center

    Hill, Ryan M.; Pettit, Jeremy W.; Green, Kelly L.; Morgan, Sharon T.; Schatte, Dawnelle J.

    2012-01-01

    Factors distinguishing adolescents who experienced a precipitating event in the week preceding a suicidal crisis from those who did not were examined. Among 130 suicidal inpatients (mean age = 15.01 years), those who experienced a precipitating event reported significantly lower depressive symptom scores, better perceived problem solving, less…

  4. Changes in Oxygenation Levels Precede Changes in Amplitude of the EEG in Premature Infants.

    PubMed

    Caicedo, Alexander; Thewissen, Liesbeth; Smits, Anne; Naulaers, Gunnar; Allegaert, Karel; Van Huffel, Sabine

    2016-01-01

    Brain function is supported by an appropriate balance between the metabolic demand and the supply of nutrients and oxygen. However, the physiological principles behind the regulation of brain metabolism and demand in premature infants are unknown. Some studies found that changes in hemodynamic variables in this population precede changes in EEG activity; however, these studies only used descriptive statistics. This paper describes the relationship between changes in cerebral oxygenation, assessed by means of near-infrared spectroscopy (NIRS), and changes in EEG, using mathematical methods taken from information dynamics. In a cohort of 35 neonates subjected to sedation by propofol, we quantified the direction of information transfer between brain oxygenation and EEG. The results obtained indicate that, as reported in other studies, changes in NIRS are likely to precede changes in EEG activity. PMID:27526136

  5. A Decrease in Temperature and Humidity Precedes Human Rhinovirus Infections in a Cold Climate.

    PubMed

    Ikäheimo, Tiina M; Jaakkola, Kari; Jokelainen, Jari; Saukkoriipi, Annika; Roivainen, Merja; Juvonen, Raija; Vainio, Olli; Jaakkola, Jouni J K

    2016-01-01

    Both temperature and humidity may independently or jointly contribute to the risk of human rhinovirus (HRV) infections, either through altered survival and spread of viruses in the environment or due to changes in host susceptibility. This study examined the relationship between short-term variations in temperature and humidity and the risk of HRV infections in a subarctic climate. We conducted a case-crossover study among conscripts (n = 892) seeking medical attention due to respiratory symptoms during their military training and identified 147 HRV cases by real-time PCR. An average temperature, a decline in daily ambient temperature and absolute humidity (AH) during the three preceding days of the onset (hazard period) and two reference periods (a week prior and after the onset) were obtained. The average daily temperature preceding HRV infections was -9.9 ± 4.9 °C and the average AH was 2.2 ± 0.9 g/m³. An average (odds ratios (OR) 1.07 (95% confidence interval (CI) 1.00-1.15)) and maximal (OR 1.08 (1.01-1.17)) change in temperature increased the risk of HRV infections by 8% per 1 °C decrease. An average (OR 1.20 (CI 1.03-1.40)) and maximal decrease (OR 1.13 (CI 0.96-1.34)) in AH increased the risk of HRV infection by 13% and 20% per 0.5 g/m³ decrease. A higher average temperature during the three preceding days was positively associated with HRV infections (OR 1.07 (CI 1.00-1.15)). A decrease rather than low temperature and humidity per se during the preceding few days increases the risk of HRV infections in a cold climate. The information is applicable to populations residing in cold climates for appropriate personal protection and prevention of adverse health effects. PMID:27598190

  6. A Decrease in Temperature and Humidity Precedes Human Rhinovirus Infections in a Cold Climate.

    PubMed

    Ikäheimo, Tiina M; Jaakkola, Kari; Jokelainen, Jari; Saukkoriipi, Annika; Roivainen, Merja; Juvonen, Raija; Vainio, Olli; Jaakkola, Jouni J K

    2016-01-01

    Both temperature and humidity may independently or jointly contribute to the risk of human rhinovirus (HRV) infections, either through altered survival and spread of viruses in the environment or due to changes in host susceptibility. This study examined the relationship between short-term variations in temperature and humidity and the risk of HRV infections in a subarctic climate. We conducted a case-crossover study among conscripts (n = 892) seeking medical attention due to respiratory symptoms during their military training and identified 147 HRV cases by real-time PCR. An average temperature, a decline in daily ambient temperature and absolute humidity (AH) during the three preceding days of the onset (hazard period) and two reference periods (a week prior and after the onset) were obtained. The average daily temperature preceding HRV infections was -9.9 ± 4.9 °C and the average AH was 2.2 ± 0.9 g/m³. An average (odds ratios (OR) 1.07 (95% confidence interval (CI) 1.00-1.15)) and maximal (OR 1.08 (1.01-1.17)) change in temperature increased the risk of HRV infections by 8% per 1 °C decrease. An average (OR 1.20 (CI 1.03-1.40)) and maximal decrease (OR 1.13 (CI 0.96-1.34)) in AH increased the risk of HRV infection by 13% and 20% per 0.5 g/m³ decrease. A higher average temperature during the three preceding days was positively associated with HRV infections (OR 1.07 (CI 1.00-1.15)). A decrease rather than low temperature and humidity per se during the preceding few days increases the risk of HRV infections in a cold climate. The information is applicable to populations residing in cold climates for appropriate personal protection and prevention of adverse health effects.

  7. Organizational precedents for ownership and management of decentralized renewable-energy systems

    SciTech Connect

    Meunier, R.; Silversmith, J.A.

    1981-03-01

    Three existing organizational types that meet the decentralization criteria of local consumer ownership and control - cooperatives, Rural Electric Cooperatives, and municipal utilities - are examined. These three organizational precedents are analyzed in terms of their histories, structures, legal powers, sources of capital, and social and political aspects. Examples of related experiments with renewable energy technologies are given, and inferences are drawn regarding the organizations' suitability as vehicles for future implementation of decentralized renewable energy systems.

  8. Legal precedents regarding use and defensibility of risk assessment in Federal transportation of SNF and HLW

    SciTech Connect

    Bentz, E.J. Jr.; Bentz, C.B.; O`Hora, T.D.; Chen, S.Y.

    1997-04-01

    Risk assessment has become an increasingly important and essential tool in support of Federal decision-making regarding the handling, storage, disposal, and transportation of spent nuclear fuel (SNF) and high-level radioactive waste (HLW). This paper analyzes the current statutory and regulatory framework and related legal precedents with regard to SNF and HLW transportation. The authors identify key scientific and technical issues regarding the use and defensibility of risk assessment in Federal decision-making regarding anticipated shipments.

  9. Chromatin structural changes precede replication in initiated replicons during inhibition of DNA elongation

    SciTech Connect

    D'Anna, J.A.; Grady, D.L.; Tobey, R.A.

    1988-01-01

    Partial inhibition of replicative DNA synthesis by hydroxyurea or other agents produces changes in the composition and structure of bulk chromatin. We have begun to investigate the structural changes in specific regions of the genome using synchronized cells and cloned genomic probes. Current results indicate changes in chromatin structure occur preferentially in initiated replicons and can precede the replication fork during inhibition of DNA elongation. 4 refs., 2 figs.

  10. Effects of Age and Hearing Loss on Gap Detection and the Precedence Effect: Narrow-Band Stimuli

    ERIC Educational Resources Information Center

    Lister, Jennifer J.; Roberts, Richard A.

    2005-01-01

    Deficits in temporal resolution and/or the precedence effect may underlie part of the speech understanding difficulties experienced by older listeners in degraded acoustic environments. In a previous investigation, R. Roberts and J. Lister (2004) identified a positive correlation between measures of temporal resolution and the precedence effect,…

  11. Quiet Periods in Edge Turbulence Preceding the L-H Transition in NSTX

    SciTech Connect

    Zweben, S; Hager, R; Hallatschek, K; Kaye, S M; Munsat, T; Poli, F M; Roquemore, A L; Sechrest, Y

    2010-04-26

    This paper describes the first observations in NSTX of ‘quiet periods’ in the edge turbulence preceding the L-H transition, as diagnosed by the GPI diagnostic near the outer midplane separatrix. During these quiet periods the GPI Dα light emission pattern was transiently similar to that seen during Hmode, i.e. with a relatively small fraction of the GPI light emission located outside the separatrix. These quiet periods had a frequency of ~3 kHz for at least 30 msec before the L-H transition, and were correlated with changes in the direction of the local poloidal velocity. The GPI turbulence images were also analyzed to obtain an estimate for the dimensionless poloidal shearing S =(dVp/dr)(Lr/Lp)τ. The values of S were strongly modulated by the quiet periods, but not otherwise varying for at least 30 msec preceding the L-H transition. Since neither the quiet periods nor the shear flow increased significantly immediately preceding the L-H transition, neither of these appears to be the trigger for this transition, at least for these cases in NSTX.

  12. The Response of Durum Wheat to the Preceding Crop in a Mediterranean Environment

    PubMed Central

    Ercoli, Laura; Masoni, Alessandro; Pampana, Silvia; Mariotti, Marco; Arduini, Iduna

    2014-01-01

    Crop sequence is an important management practice that may affect durum wheat (Triticum durum Desf.) production. Field research was conducted in 2007-2008 and 2008-2009 seasons in a rain-fed cold Mediterranean environment to examine the impact of the preceding crops alfalfa (Medicago sativa L.), maize (Zea mays L.), sunflower (Helianthus annuus L.), and bread wheat (Triticum aestivum L.) on yield and N uptake of four durum wheat varieties. The response of grain yield of durum wheat to the preceding crop was high in 2007-2008 and was absent in the 2008-2009 season, because of the heavy rainfall that negatively impacted establishment, vegetative growth, and grain yield of durum wheat due to waterlogging. In the first season, durum wheat grain yield was highest following alfalfa, and was 33% lower following wheat. The yield increase of durum wheat following alfalfa was mainly due to an increased number of spikes per unit area and number of kernels per spike, while the yield decrease following wheat was mainly due to a reduction of spike number per unit area. Variety growth habit and performance did not affect the response to preceding crop and varieties ranked in the order Levante > Saragolla = Svevo > Normanno. PMID:25401153

  13. Two sources of meaning in infant communication: preceding action contexts and act-accompanying characteristics.

    PubMed

    Liszkowski, Ulf

    2014-09-19

    How do infants communicate before they have acquired a language? This paper supports the hypothesis that infants possess social-cognitive skills that run deeper than language alone, enabling them to understand others and make themselves understood. I suggested that infants, like adults, use two sources of extralinguistic information to communicate meaningfully and react to and express communicative intentions appropriately. In support, a review of relevant experiments demonstrates, first, that infants use information from preceding shared activities to tailor their comprehension and production of communication. Second, a series of novel findings from our laboratory shows that in the absence of distinguishing information from preceding routines or activities, infants use accompanying characteristics (such as prosody and posture) that mark communicative intentions to extract and transmit meaning. Findings reveal that before infants begin to speak they communicate in meaningful ways by binding preceding and simultaneous multisensory information to a communicative act. These skills are not only a precursor to language, but also an outcome of social-cognitive development and social experience in the first year of life. PMID:25092662

  14. 21 CFR 172.410 - Calcium silicate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium silicate. 172.410 Section 172.410 Food and... PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Anticaking Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used in food in accordance with...

  15. 21 CFR 172.720 - Calcium lactobionate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium lactobionate. 172.720 Section 172.720 Food....720 Calcium lactobionate. The food additive calcium lactobionate may be safely used in food in accordance with the following prescribed conditions: (a) The food additive is the calcium salt of...

  16. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown...

  17. 21 CFR 184.1199 - Calcium gluconate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium gluconate. 184.1199 Section 184.1199 Food... GRAS § 184.1199 Calcium gluconate. (a) Calcium gluconate ( 2Ca, CAS Reg. No. 299-28-5) is the calcium salt of gluconic acid which may be produced by neutralization of gluconic acid with lime or...

  18. 21 CFR 172.410 - Calcium silicate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be...

  19. 21 CFR 172.715 - Calcium lignosulfonate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium lignosulfonate. 172.715 Section 172.715....715 Calcium lignosulfonate. Calcium lignosulfonate may be safely used in or on food, subject to the provisions of this section. (a) Calcium lignosulfonate consists of sulfonated lignin, primarily as...

  20. 21 CFR 184.1199 - Calcium gluconate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium gluconate. 184.1199 Section 184.1199 Food... Specific Substances Affirmed as GRAS § 184.1199 Calcium gluconate. (a) Calcium gluconate ( 2Ca, CAS Reg. No. 299-28-5) is the calcium salt of gluconic acid which may be produced by neutralization of...

  1. 21 CFR 172.715 - Calcium lignosulfonate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium lignosulfonate. 172.715 Section 172.715... CONSUMPTION Other Specific Usage Additives § 172.715 Calcium lignosulfonate. Calcium lignosulfonate may be safely used in or on food, subject to the provisions of this section. (a) Calcium lignosulfonate...

  2. 21 CFR 184.1199 - Calcium gluconate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium gluconate. 184.1199 Section 184.1199 Food... Specific Substances Affirmed as GRAS § 184.1199 Calcium gluconate. (a) Calcium gluconate ( 2Ca, CAS Reg. No. 299-28-5) is the calcium salt of gluconic acid which may be produced by neutralization of...

  3. 21 CFR 172.720 - Calcium lactobionate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium lactobionate. 172.720 Section 172.720 Food... Other Specific Usage Additives § 172.720 Calcium lactobionate. The food additive calcium lactobionate... additive is the calcium salt of lactobionic acid (4-(β,D-galactosido)-D-gluconic acid) produced by...

  4. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown...

  5. 21 CFR 172.410 - Calcium silicate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be...

  6. 21 CFR 184.1199 - Calcium gluconate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium gluconate. 184.1199 Section 184.1199 Food... Specific Substances Affirmed as GRAS § 184.1199 Calcium gluconate. (a) Calcium gluconate ( 2Ca, CAS Reg. No. 299-28-5) is the calcium salt of gluconic acid which may be produced by neutralization of...

  7. 21 CFR 172.720 - Calcium lactobionate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium lactobionate. 172.720 Section 172.720 Food... Other Specific Usage Additives § 172.720 Calcium lactobionate. The food additive calcium lactobionate... additive is the calcium salt of lactobionic acid (4-(β,D-galactosido)-D-gluconic acid) produced by...

  8. 21 CFR 172.715 - Calcium lignosulfonate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium lignosulfonate. 172.715 Section 172.715... CONSUMPTION Other Specific Usage Additives § 172.715 Calcium lignosulfonate. Calcium lignosulfonate may be safely used in or on food, subject to the provisions of this section. (a) Calcium lignosulfonate...

  9. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown...

  10. 21 CFR 172.715 - Calcium lignosulfonate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium lignosulfonate. 172.715 Section 172.715... CONSUMPTION Other Specific Usage Additives § 172.715 Calcium lignosulfonate. Calcium lignosulfonate may be safely used in or on food, subject to the provisions of this section. (a) Calcium lignosulfonate...

  11. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown...

  12. 21 CFR 172.720 - Calcium lactobionate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium lactobionate. 172.720 Section 172.720 Food... Other Specific Usage Additives § 172.720 Calcium lactobionate. The food additive calcium lactobionate... additive is the calcium salt of lactobionic acid (4-(β,D-galactosido)-D-gluconic acid) produced by...

  13. 21 CFR 184.1199 - Calcium gluconate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium gluconate. 184.1199 Section 184.1199 Food... Specific Substances Affirmed as GRAS § 184.1199 Calcium gluconate. (a) Calcium gluconate ( 2Ca, CAS Reg. No. 299-28-5) is the calcium salt of gluconic acid which may be produced by neutralization of...

  14. 21 CFR 172.410 - Calcium silicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be...

  15. Occurrence of anomalous seismic activity preceding large to great earthquakes in northeast India region with special reference to 6 August 1988

    NASA Astrophysics Data System (ADS)

    Singh, H. N.; Shanker, D.; Singh, V. P.

    2005-02-01

    Seismicity database from 1860 to 1985 of northeast India region bounded by the area 20°-32°N and 82°-100°E have been analyzed for the identification of precursory swarm/anomalous seismic activity preceding large to great earthquakes with M ≥ 7.5. It is observed that with the exception of three earthquakes (1908, 1912 and 1918), the large earthquakes of 1897, 1946, 1947, 1950 and 1951/1952 were preceded by well-developed epoch of swarm/anomalous seismic activity in space and time well before their occurrence. The seismicity is observed to fluctuate in the order of low-high-low ranging from 0-0.5, 01-33 to 0-0.7 events/year prior to these mainshocks during the epochs of normal/background, swarm/anomalous and gap/quiescence, respectively. The duration of precursory gap is observed to vary from 11 to 17 years for mainshocks of M 7.5-8.0, and from 23 to 27 years for M 8.7 and this period is dependent on the magnitude of the mainshocks. Using the values of magnitude of mainshock ( Mm), average magnitude of swarm ( Mp) and the precursory time gap ( Tp), the following predictive equations are established for the region: M=1.37M-1.40 M=3log⁡T-3.27 All the major earthquakes with mb ≥ 6.1 occurred during 1963-1988 have been investigated for their association with anomalous seismicity/precursory swarms using the events with cutoff magnitude mb ≥ 4.5. Eleven such events have occurred in the region during the period except one earthquake of 29 May 1976. All the remaining 10 earthquakes were associated in some forms of anomalous seismicity epochs. Well-defined patterns of anomalous seismicity are observed prior to 1964-1965, 12 August 1976 and 30 December 1984 ( mb 5.6). All these mainshocks are preceded by seismicity patterns in the order of low-high-low similar to that observed prior to the mainshocks from 1897 to 1962. The anomalous seismicity epoch is delineated with extremely high annual earthquake frequency, which was preceded and followed by extremely low

  16. The Effects of a Calcium-Rich Pre-Exercise Meal on Biomarkers of Calcium Homeostasis in Competitive Female Cyclists: A Randomised Crossover Trial

    PubMed Central

    Haakonssen, Eric C.; Ross, Megan L.; Knight, Emma J.; Cato, Louise E.; Nana, Alisa; Wluka, Anita E.; Cicuttini, Flavia M.; Wang, Bing H.; Jenkins, David G.; Burke, Louise M.

    2015-01-01

    Cycling is recognised as a sport in which there is a high incidence of poor bone health. Sweat calcium losses may contribute to this. Purpose To examine whether a calcium-rich pre-exercise meal attenuates exercise-induced perturbations of bone calcium homeostasis caused by maintenance of sweat calcium losses. Methods Using a randomized, counterbalanced crossover design, 32 well-trained female cyclists completed two 90 min cycling trials separated by 1 day. Exercise trials were preceded 2 hours by either a calcium-rich (1352 ± 53 mg calcium) dairy based meal (CAL) or a control meal (CON; 46 ± 7 mg calcium). Blood was sampled pre-trial; pre-exercise; and immediately, 40 min, 100 min and 190 min post-exercise. Blood was analysed for ionized calcium and biomarkers of bone resorption (Cross Linked C-Telopeptide of Type I Collagen (CTX-I), Cross Linked C-Telopeptide of Type II Collagen (CTX-II), Parathyroid Hormone (PTH), and bone formation (Procollagen I N-Terminal Propeptide (PINP)) using the established enzyme-linked immunosorbent assay technique. Results PTH and CTX-I increased from pre-exercise to post-exercise in both conditions but was attenuated in CAL (p < 0.001). PTH was 1.55 [1.20, 2.01] times lower in CAL immediately post-exercise and 1.45 [1.12, 1.88] times lower at 40 min post-exercise. CTX-I was 1.40 [1.15, 1.70] times lower in CAL at immediately post-exercise, 1.30 [1.07, 1.57] times lower at 40 min post-exercise and 1.22 [1.00, 1.48] times lower at 190 min post-exercise (p < 0.05). There was no significant interaction between pre-exercise meal condition and time point for CTX-II (p = 0.732) or PINP (p = 0.819). Conclusion This study showed that a calcium-rich pre-exercise breakfast meal containing ~1350 mg of calcium consumed ~90 min before a prolonged and high intensity bout of stationary cycling attenuates the exercise induced rise in markers of bone resorption – PTH and CTX-I. Trial Registration Australian New Zealand Clinical Trials Registry

  17. Measuring Algorithm for the Distance to a Preceding Vehicle on Curve Road Using On-Board Monocular Camera

    NASA Astrophysics Data System (ADS)

    Yu, Guizhen; Zhou, Bin; Wang, Yunpeng; Wun, Xinkai; Wang, Pengcheng

    2015-12-01

    Due to more severe challenges of traffic safety problems, the Advanced Driver Assistance Systems (ADAS) has received widespread attention. Measuring the distance to a preceding vehicle is important for ADAS. However, the existing algorithm focuses more on straight road sections than on curve measurements. In this paper, we present a novel measuring algorithm for the distance to a preceding vehicle on a curve road using on-board monocular camera. Firstly, the characteristics of driving on the curve road is analyzed and the recognition of the preceding vehicle road area is proposed. Then, the vehicle detection and distance measuring algorithms are investigated. We have verified these algorithms on real road driving. The experimental results show that this method proposed in the paper can detect the preceding vehicle on curve roads and accurately calculate the longitudinal distance and horizontal distance to the preceding vehicle.

  18. Facilitation of cytosolic calcium wave propagation by local calcium uptake into the sarcoplasmic reticulum in cardiac myocytes.

    PubMed

    Maxwell, Joshua T; Blatter, Lothar A

    2012-12-01

    The widely accepted paradigm for cytosolic Ca(2+) wave propagation postulates a 'fire-diffuse-fire' mechanism where local Ca(2+)-induced Ca(2+) release (CICR) from the sarcoplasmic reticulum (SR) via ryanodine receptor (RyR) Ca(2+) release channels diffuses towards and activates neighbouring release sites, resulting in a propagating Ca(2+) wave. A recent challenge to this paradigm proposed the requirement for an intra-SR 'sensitization' Ca(2+) wave that precedes the cytosolic Ca(2+) wave and primes RyRs from the luminal side to CICR. Here, we tested this hypothesis experimentally with direct simultaneous measurements of cytosolic ([Ca(2+)](i); rhod-2) and intra-SR ([Ca(2+)](SR); fluo-5N) calcium signals during wave propagation in rabbit ventricular myocytes, using high resolution fluorescence confocal imaging. The increase in [Ca(2+)](i) at the wave front preceded depletion of the SR at each point along the calcium wave front, while during this latency period a transient increase of [Ca(2+)](SR) was observed. This transient elevation of [Ca(2+)](SR) could be identified at individual release junctions and depended on the activity of the sarco-endoplasmic reticulum Ca(2+)-ATPase (SERCA). Increased SERCA activity (β-adrenergic stimulation with 1 μM isoproterenol (isoprenaline)) decreased the latency period and increased the amplitude of the transient elevation of [Ca(2+)](SR), whereas inhibition of SERCA (3 μM cyclopiazonic acid) had the opposite effect. In conclusion, the data provide experimental evidence that local Ca(2+) uptake by SERCA into the SR facilitates the propagation of cytosolic Ca(2+) waves via luminal sensitization of the RyR, and supports a novel paradigm of a 'fire-diffuse-uptake-fire' mechanism for Ca(2+) wave propagation in cardiac myocytes.

  19. The calcium sensor Copine-6 regulates spine structural plasticity and learning and memory.

    PubMed

    Reinhard, Judith R; Kriz, Alexander; Galic, Milos; Angliker, Nico; Rajalu, Mathieu; Vogt, Kaspar E; Ruegg, Markus A

    2016-01-01

    Hippocampal long-term potentiation (LTP) represents the cellular response of excitatory synapses to specific patterns of high neuronal activity and is required for learning and memory. Here we identify a mechanism that requires the calcium-binding protein Copine-6 to translate the initial calcium signals into changes in spine structure. We show that Copine-6 is recruited from the cytosol of dendrites to postsynaptic spine membranes by calcium transients that precede LTP. Cpne6 knockout mice are deficient in hippocampal LTP, learning and memory. Hippocampal neurons from Cpne6 knockouts lack spine structural plasticity as do wild-type neurons that express a Copine-6 calcium mutant. The function of Copine-6 is based on its binding, activating and recruiting the Rho GTPase Rac1 to cell membranes. Consistent with this function, the LTP deficit of Cpne6 knockout mice is rescued by the actin stabilizer jasplakinolide. These data show that Copine-6 links activity-triggered calcium signals to spine structural plasticity necessary for learning and memory. PMID:27194588

  20. The calcium sensor Copine-6 regulates spine structural plasticity and learning and memory

    PubMed Central

    Reinhard, Judith R.; Kriz, Alexander; Galic, Milos; Angliker, Nico; Rajalu, Mathieu; Vogt, Kaspar E.; Ruegg, Markus A.

    2016-01-01

    Hippocampal long-term potentiation (LTP) represents the cellular response of excitatory synapses to specific patterns of high neuronal activity and is required for learning and memory. Here we identify a mechanism that requires the calcium-binding protein Copine-6 to translate the initial calcium signals into changes in spine structure. We show that Copine-6 is recruited from the cytosol of dendrites to postsynaptic spine membranes by calcium transients that precede LTP. Cpne6 knockout mice are deficient in hippocampal LTP, learning and memory. Hippocampal neurons from Cpne6 knockouts lack spine structural plasticity as do wild-type neurons that express a Copine-6 calcium mutant. The function of Copine-6 is based on its binding, activating and recruiting the Rho GTPase Rac1 to cell membranes. Consistent with this function, the LTP deficit of Cpne6 knockout mice is rescued by the actin stabilizer jasplakinolide. These data show that Copine-6 links activity-triggered calcium signals to spine structural plasticity necessary for learning and memory. PMID:27194588

  1. Calcium transport in turtle bladder

    SciTech Connect

    Sabatini, S.; Kurtzman, N.A. )

    1987-12-01

    Unidirectional {sup 45}Ca fluxes were measured in the turtle bladder under open-circuit and short-circuit conditions. In the open-circuited state net calcium flux (J{sup net}{sub Ca}) was secretory (serosa to mucosa). Ouabain reversed J{sup net}{sub Ca} to an absorptive flux. Amiloride reduced both fluxes such that J{sup net}{sub Ca} was not significantly different from zero. Removal of mucosal sodium caused net calcium absorption; removal of serosal sodium caused calcium secretion. When bladders were short circuited, J{sup net}{sub Ca} decreased to approximately one-third of control value but remained secretory. When ouabain was added under short-circuit conditions, J{sup net}{sub Ca} was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue {sup 45}Ca content was {approx equal}30-fold lower when the isotope was placed in the mucosal bath, suggesting that the apical membrane is the resistance barrier to calcium transport. The results obtained in this study are best explained by postulating a Ca{sup 2+}-ATPase on the serosa of the turtle bladder epithelium and a sodium-calcium antiporter on the mucosa. In this model, the energy for calcium movement would be supplied, in large part, by the Na{sup +}-K{sup +}-ATPase. By increasing cell sodium, ouabain would decrease the activity of the mucosal sodium-calcium exchanger (or reverse it), uncovering active calcium transport across the serosa.

  2. Medical therapy, calcium oxalate urolithiasis

    NASA Technical Reports Server (NTRS)

    Ruml, L. A.; Pearle, M. S.; Pak, C. Y.

    1997-01-01

    The development of diagnostic protocols that identify specific risk factors for calcium oxalate nephrolithiasis has led to the formulation of directed medical regimens that are aimed at correcting the underlying metabolic disturbances. Initiation of these treatment programs has reduced markedly the rate of stone formation in the majority of patients who form stones. This article discusses the rationale that underlies the choice of medical therapy for the various pathophysiologic causes of calcium oxalate nephrolithiasis and the appropriate use of available medications.

  3. Calcium, iron and neuronal function.

    PubMed

    Hidalgo, Cecilia; Núñez, Marco T

    2007-01-01

    Calcium and iron play dual roles in neuronal function: they are both essential but when present in excess they cause neuronal damage and may even induce neuronal death. Calcium signals are required for synaptic plasticity, a neuronal process that entails gene expression and which is presumably the cellular counterpart of cognitive brain functions such as learning and memory. Neuronal activity generates cytoplasmic and nuclear calcium signals that in turn stimulate pathways that promote the transcription of genes known to participate in synaptic plasticity. In addition, evidence discussed in this article shows that iron deficiency causes learning and memory impairments that persist following iron repletion, indicating that iron is necessary for normal development of cognitive functions. Recent results from our group indicate that iron is required for long-term potentiation in hippocampal CA1 neurons and that iron stimulates ryanodine receptor-mediated calcium release through ROS produced via the Fenton reaction leading to stimulation of the ERK signaling pathway. These combined results support a coordinated action between iron and calcium in synaptic plasticity and raise the possibility that elevated iron levels may contribute to neuronal degeneration through excessive intracellular calcium increase caused by iron-induced oxidative stress. PMID:17505966

  4. Gravity, Calcium, and Bone: Update, 1989

    NASA Technical Reports Server (NTRS)

    Arnaud, Sara B.; Morey-Holton, Emily

    1991-01-01

    Some of the results of recent short-term flights and ground-based experiments that have contributed new insights into skeletal adaptation, calcium metabolism, and growth processes in 0 g, are highlighted. After 6 months in space, bone demineralization, invariably involving the os calcis, was found not to extend to the lumbar spine in 4 exercising cosmonauts. A flight experiment in the Space Shuttle crew has documented the early events in the calcium endocrine system during spaceflight. On the ground, brief and long-term bed rest studies of healthy volunteers in the head-down tile (HDT) model of weightlessness were completed. The skeleton of the adult male responds more rapidly to unloading than previously recognized. Regional changes in bone density can be quantified in only 30 days, are highly individual, and follow the direction of gravitational forces in the HDT model during inactivity. Bone biopsy results in healthy volunteers after bed rest differ from results in paraplegics from the same sampling site. Flight experiments in growing rats reveal changes in the composition of bone mineral and matrix in the femur postflight that were found to be highly regional and suggestive of an effect of gravity on mineral distribution. These observations may be relevant to the results from an earlier Cosmos flight where artificial gravity in space was found to maintain bone strength, but not to correct the radial growth deficit.

  5. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium lactate. 184.1207 Section 184.1207 Food... Specific Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications...

  6. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium lactate. 184.1207 Section 184.1207 Food and... Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where x is any... calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of the Food...

  7. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium lactate. 184.1207 Section 184.1207 Food... Specific Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications...

  8. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium lactate. 184.1207 Section 184.1207 Food... Specific Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications...

  9. Calcium metabolism and cardiovascular function after spaceflight

    NASA Technical Reports Server (NTRS)

    Hatton, Daniel C.; Yue, Qi; Dierickx, Jacqueline; Roullet, Chantal; Otsuka, Keiichi; Watanabe, Mitsuaki; Coste, Sarah; Roullet, Jean Baptiste; Phanouvang, Thongchan; Orwoll, Eric; Orwoll, Shiela; McCarron, David A.

    2002-01-01

    To determine the influence of dietary calcium on spaceflight-induced alterations in calcium metabolism and blood pressure (BP), 9-wk-old spontaneously hypertensive rats, fed either high- (2%) or low-calcium (0.02%) diets, were flown on an 18-day shuttle flight. On landing, flight animals had increased ionized calcium (P < 0.001), elevated parathyroid hormone levels (P < 0.001), reduced calcitonin levels (P < 0.05), unchanged 1,25(OH)(2)D(3) levels, and elevated skull (P < 0.01) and reduced femur bone mineral density. Basal and thrombin-stimulated platelet free calcium (intracellular calcium concentration) were also reduced (P < 0.05). There was a tendency for indirect systolic BP to be reduced in conscious flight animals (P = 0.057). However, mean arterial pressure was elevated (P < 0.001) after anesthesia. Dietary calcium altered all aspects of calcium metabolism (P < 0.001), as well as BP (P < 0.001), but the only interaction with flight was a relatively greater increase in ionized calcium in flight animals fed low- compared with high-calcium diets (P < 0.05). The results indicate that 1) flight-induced disruptions of calcium metabolism are relatively impervious to dietary calcium in the short term, 2) increased ionized calcium did not normalize low-calcium-induced elevations of BP, and 3) parathyroid hormone was paradoxically increased in the high-calcium-fed flight animals after landing.

  10. Mitochondrial calcium uptake.

    PubMed

    Williams, George S B; Boyman, Liron; Chikando, Aristide C; Khairallah, Ramzi J; Lederer, W J

    2013-06-25

    Calcium (Ca(2+)) uptake into the mitochondrial matrix is critically important to cellular function. As a regulator of matrix Ca(2+) levels, this flux influences energy production and can initiate cell death. If large, this flux could potentially alter intracellular Ca(2+) ([Ca(2+)]i) signals. Despite years of study, fundamental disagreements on the extent and speed of mitochondrial Ca(2+) uptake still exist. Here, we review and quantitatively analyze mitochondrial Ca(2+) uptake fluxes from different tissues and interpret the results with respect to the recently proposed mitochondrial Ca(2+) uniporter (MCU) candidate. This quantitative analysis yields four clear results: (i) under physiological conditions, Ca(2+) influx into the mitochondria via the MCU is small relative to other cytosolic Ca(2+) extrusion pathways; (ii) single MCU conductance is ∼6-7 pS (105 mM [Ca(2+)]), and MCU flux appears to be modulated by [Ca(2+)]i, suggesting Ca(2+) regulation of MCU open probability (P(O)); (iii) in the heart, two features are clear: the number of MCU channels per mitochondrion can be calculated, and MCU probability is low under normal conditions; and (iv) in skeletal muscle and liver cells, uptake per mitochondrion varies in magnitude but total uptake per cell still appears to be modest. Based on our analysis of available quantitative data, we conclude that although Ca(2+) critically regulates mitochondrial function, the mitochondria do not act as a significant dynamic buffer of cytosolic Ca(2+) under physiological conditions. Nevertheless, with prolonged (superphysiological) elevations of [Ca(2+)]i, mitochondrial Ca(2+) uptake can increase 10- to 1,000-fold and begin to shape [Ca(2+)]i dynamics.

  11. Calcium signaling and cytotoxicity.

    PubMed Central

    Kass, G E; Orrenius, S

    1999-01-01

    The divalent calcium cation Ca(2+) is used as a major signaling molecule during cell signal transduction to regulate energy output, cellular metabolism, and phenotype. The basis to the signaling role of Ca(2+) is an intricate network of cellular channels and transporters that allow a low resting concentration of Ca(2+) in the cytosol of the cell ([Ca(2+)]i) but that are also coupled to major dynamic and rapidly exchanging stores. This enables extracellular signals from hormones and growth factors to be transduced as [Ca(2+)]i spikes that are amplitude and frequency encoded. There is considerable evidence that a number of toxic environmental chemicals target these Ca(2+) signaling processes, alter them, and induce cell death by apoptosis. Two major pathways for apoptosis will be considered. The first one involves Ca(2+)-mediated expression of ligands that bind to and activate death receptors such as CD95 (Fas, APO-1). In the second pathway, Ca(2+) has a direct toxic effect and its primary targets include the mitochondria and the endoplasmic reticulum (ER). Mitochondria may respond to an apoptotic Ca(2+) signal by the selective release of cytochrome c or through enhanced production of reactive oxygen species and opening of an inner mitochondrial membrane pore. Toxic agents such as the environmental pollutant tributyltin or the natural plant product thapsigargin, which deplete the ER Ca(2+) stores, will induce as a direct result of this effect the opening of plasma membrane Ca(2+) channels and an ER stress response. In contrast, under some conditions, Ca(2+) signals may be cytoprotective and antagonize the apoptotic machinery. Images Figure 1 Figure 2 Figure 3 PMID:10229704

  12. Formation of calcium complexes by borogluconate in vitro and during calcium borogluconate infusion in sheep.

    PubMed

    Farningham, D A

    1985-07-01

    The effect of borogluconate on plasma calcium fractions was studied in vitro and in vivo in sheep. In vitro calcium chloride was more effective in raising ionised plasma calcium than calcium borogluconate. Sodium borate or gluconate added to blood caused only small decreases in blood ionised calcium. However, together, a synergistic reduction in ionised calcium was observed. Following calcium borogluconate infusions into sheep, total plasma calcium rose primarily because of an increase in the unionised ultrafiltrable fraction. Other changes observed following the infusion were hypercalciuria, decreased glomerular filtration rate and acidosis. Sodium borogluconate administered subcutaneously lowered total plasma calcium. This probably resulted from enhanced calcium excretion. It is suggested that since the anionic component of calcium solutions alters the availability and retention of calcium, it is likely to affect clinical efficacy significantly.

  13. Increased calcium bioavailability in mice fed genetically engineered plants lacking calcium oxalate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioavailable calcium affects bone formation and calcification. Here we investigate how a single gene mutation altering calcium partitioning in the model forage crop Medicago truncatula affects calcium bioavailability. Previously, the cod5 M. truncatula mutant was identified which contains identical ...

  14. [Calcium metabolism characteristics in microgravity].

    PubMed

    Grigor'ev, A I; Larina, I M; Morukov, B V

    1999-06-01

    The results of research of calcium exchange parameters at cosmonauts taken part in long space flights (SF) onboard of orbital stations "SALUT" and "MIR" within 1978-1998 were generalized. The analysis of data received during observation of 44 cosmonauts (18 of them have taken part in long SF twice) was done. The observation was carried out before and after SF by duration 30-438 days. The content of a total calcium in blood serum was increased basically by the increase of its ionized fraction after flights of moderate (3-6 months) and large duration (6-14 months) along with the significant increase of PTH and decrease of calcitonin levels. The content of osteocalcin after SF was increased. Three cosmonauts participated in research of calcium kinetics using stable isotopes before, in time and after a 115-day SF. Reduction of intestinal absorption, excretion through a gastrointestinal tract, and increase of calcium excretion with urine were marked in time of SF. In early postflight period a level of intestinal absorption, on the average, was much lower than in SF, and the calcium removal through intestine was increased. Both renal and intestinal excretion of calcium were not normalized in 3.5-4.5 months after end of SF. Increase of resorbtive processes in bone tissues which induced negative bone balance during flight was observed in all test subjects, proceeding from estimations of speed of the basic calcium flows made on the basis of mathematical modeling. The conclusion about decrease in speed of bone tissue remodeling and strengthening of its resorption proves to be true by data of research of biochemical and endocrine markers.

  15. First-report on Mesozoic eclogite-facies metamorphism preceding Barrovian overprint from the western Rhodope (Chalkidiki, northern Greece)

    NASA Astrophysics Data System (ADS)

    Kydonakis, Konstantinos; Moulas, Evangelos; Chatzitheodoridis, Elias; Brun, Jean-Pierre; Kostopoulos, Dimitrios

    2015-04-01

    The Chalkidiki block in Northern Greece represents the southwesternmost piece of the ultrahigh-pressure Rhodope and has played an important role in the evolution of the North Aegean. The eastern part of the Chalkidiki block is a basement complex (Vertiskos Unit) that is made largely of Palaeozoic granitoids and clastic sediments that metamorphosed during the Mesozoic. This basement is traditionally considered as part of the Rhodopean hanging-wall, an assignment mainly supported by the absence of high-pressure mineral indicators and the presence of a regional medium-pressure/medium-temperature amphibolite-facies Barrovian metamorphic imprint. Toward the west, the basement is juxtaposed with meta-sedimentary (Circum-Rhodope belt) and arc units (Chortiatis Magmatic Suite) that carry evidence of a Mesozoic high-pressure/low-temperature event. In this study, garnet-staurolite-mica schists from the eastern part of the basement were examined by means of micro-textures, mineral chemistry and isochemical phase-diagram sections in the system NCKFMASHMn(Ti) [Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2O-MnO-(TiO2)]. The schists represent former Mesozoic sedimentary sequences deposited on the Palaeozoic basement. We document the presence of a relict eclogite-facies mineral assemblage (garnet + chloritoid + phengite + rutile) in an amphibolite-facies matrix composed of garnet + staurolite + phengite ± kyanite. Model results suggest the existence of a high-pressure/medium-temperature metamorphic event (1.9 GPa/520 °C) that preceded regional re-equilibration at medium-pressure/medium-temperature conditions (1.2 GPa/620 °C). Clearly, the eastern part of the Chalkidiki block (basement complex) retains memory of an as yet unidentified Mesozoic eclogitic metamorphic event that was largely erased by the later Barrovian overprint. In light of our findings, the basement complex of the Chalkidiki block shares a common tectono-metamorphic evolution with both the high-pressure units to the west

  16. Diffusive spatio-temporal noise in a first-passage time model for intracellular calcium release

    NASA Astrophysics Data System (ADS)

    Flegg, Mark B.; Rüdiger, Sten; Erban, Radek

    2013-04-01

    The intracellular release of calcium from the endoplasmic reticulum is controlled by ion channels. The resulting calcium signals exhibit a rich spatio-temporal signature, which originates at least partly from microscopic fluctuations. While stochasticity in the gating transition of ion channels has been incorporated into many models, the distribution of calcium is usually described by deterministic reaction-diffusion equations. Here we test the validity of the latter modeling approach by using two different models to calculate the frequency of localized calcium signals (calcium puffs) from clustered IP3 receptor channels. The complexity of the full calcium system is here limited to the basic opening mechanism of the ion channels and, in the mathematical reduction simplifies to the calculation of a first passage time. Two models are then studied: (i) a hybrid model, where channel gating is treated stochastically, while calcium concentration is deterministic and (ii) a fully stochastic model with noisy channel gating and Brownian calcium ion motion. The second model utilises the recently developed two-regime method [M. B. Flegg, S. J. Chapman, and R. Erban, "The two-regime method for optimizing stochastic reaction-diffusion simulations," J. R. Soc., Interface 9, 859-868 (2012)], 10.1098/rsif.2011.0574 in order to simulate a large domain with precision required only near the Ca2+ absorbing channels. The expected time for a first channel opening that results in a calcium puff event is calculated. It is found that for a large diffusion constant, predictions of the interpuff time are significantly overestimated using the model (i) with a deterministic non-spatial calcium variable. It is thus demonstrated that the presence of diffusive noise in local concentrations of intracellular Ca2+ ions can substantially influence the occurrence of calcium signals. The presented approach and results may also be relevant for other cell-physiological first-passage time problems with

  17. Plasma membrane calcium channels in cancer: Alterations and consequences for cell proliferation and migration.

    PubMed

    Déliot, Nadine; Constantin, Bruno

    2015-10-01

    The study of calcium channels in molecular mechanisms of cancer transformation is still a novel area of research. Several studies, mostly conducted on cancer cell lines, however support the idea that a diversity of plasma membrane channels participates in the remodeling of Ca2+ homeostasis, which regulates various cancer hallmarks such as uncontrolled multiplication and increase in migration and invasion abilities. However few is still understood concerning the intracellular signaling cascades mobilized by calcium influx participating to cancer cell behavior. This review intends to gather some of these pathways dependent on plasma membrane calcium channels and described in prostate, breast and lung cancer cell lines. In these cancer cell types, the calcium channels involved in calcium signaling pathways promoting cancer behaviors are mostly non-voltage activated calcium channels and belong to the TRP superfamily (TRPC, TPRPV and TRPM families) and the Orai family. TRP and Orai channels are part of many signaling cascades involving the activation of transmembrane receptors by extracellular ligand from the tumor environment. TRPV can sense changes in the physical and chemical environment of cancer cells and TRPM7 are stretch activated and sensitive to cholesterol. Changes in activation and or expression of plasma-membrane calcium channels affect calcium-dependent signaling processes relevant to tumorigenesis. The studies cited in this review suggest that an increase in plasma membrane calcium channel expression and/or activity sustain an elevated calcium entry (constitutive or under the control of extracellular signals) promoting higher cell proliferation and migration in most cases. A variety of non-voltage-operated calcium channels display change expression and/or activity in a same cancer type and cooperate to the same process relevant to cancer cell behavior, or can be involved in a different sequence of events during the tumorigenesis. This article is part of a

  18. Genetic evidence in the mouse solidifies the calcium hypothesis of myofiber death in muscular dystrophy

    PubMed Central

    Burr, A R; Molkentin, J D

    2015-01-01

    Muscular dystrophy (MD) refers to a clinically and genetically heterogeneous group of degenerative muscle disorders characterized by progressive muscle wasting and often premature death. Although the primary defect underlying most forms of MD typically results from a loss of sarcolemmal integrity, the secondary molecular mechanisms leading to muscle degeneration and myofiber necrosis is debated. One hypothesis suggests that elevated or dysregulated cytosolic calcium is the common transducing event, resulting in myofiber necrosis in MD. Previous measurements of resting calcium levels in myofibers from dystrophic animal models or humans produced equivocal results. However, recent studies in genetically altered mouse models have largely solidified the calcium hypothesis of MD, such that models with artificially elevated calcium in skeletal muscle manifest fulminant dystrophic-like disease, whereas models with enhanced calcium clearance or inhibited calcium influx are resistant to myofiber death and MD. Here, we will review the field and the recent cadre of data from genetically altered mouse models, which we propose have collectively mostly proven the hypothesis that calcium is the primary effector of myofiber necrosis in MD. This new consensus on calcium should guide future selection of drugs to be evaluated in clinical trials as well as gene therapy-based approaches. PMID:26088163

  19. Electric pulses: a flexible tool to manipulate cytosolic calcium concentrations and generate spontaneous-like calcium oscillations in mesenchymal stem cells.

    PubMed

    de Menorval, Marie-Amelie; Andre, Franck M; Silve, Aude; Dalmay, Claire; Français, Olivier; Le Pioufle, Bruno; Mir, Lluis M

    2016-01-01

    Human adipose mesenchymal stem cells (haMSCs) are multipotent adult stem cells of great interest in regenerative medicine or oncology. They present spontaneous calcium oscillations related to cell cycle progression or differentiation but the correlation between these events is still unclear. Indeed, it is difficult to mimic haMSCs spontaneous calcium oscillations with chemical means. Pulsed electric fields (PEFs) can permeabilise plasma and/or organelles membranes depending on the applied pulses and therefore generate cytosolic calcium peaks by recruiting calcium from the external medium or from internal stores. We show that it is possible to mimic haMSCs spontaneous calcium oscillations (same amplitude, duration and shape) using 100 μs PEFs or 10 ns PEFs. We propose a model that explains the experimental situations reported. PEFs can therefore be a flexible tool to manipulate cytosolic calcium concentrations. This tool, that can be switched on and off instantaneously, contrary to chemicals agents, can be very useful to investigate the role of calcium oscillations in cell physiology and/or to manipulate cell fate. PMID:27561994

  20. Electric pulses: a flexible tool to manipulate cytosolic calcium concentrations and generate spontaneous-like calcium oscillations in mesenchymal stem cells

    PubMed Central

    de Menorval, Marie-Amelie; Andre, Franck M.; Silve, Aude; Dalmay, Claire; Français, Olivier; Le Pioufle, Bruno; Mir, Lluis M.

    2016-01-01

    Human adipose mesenchymal stem cells (haMSCs) are multipotent adult stem cells of great interest in regenerative medicine or oncology. They present spontaneous calcium oscillations related to cell cycle progression or differentiation but the correlation between these events is still unclear. Indeed, it is difficult to mimic haMSCs spontaneous calcium oscillations with chemical means. Pulsed electric fields (PEFs) can permeabilise plasma and/or organelles membranes depending on the applied pulses and therefore generate cytosolic calcium peaks by recruiting calcium from the external medium or from internal stores. We show that it is possible to mimic haMSCs spontaneous calcium oscillations (same amplitude, duration and shape) using 100 μs PEFs or 10 ns PEFs. We propose a model that explains the experimental situations reported. PEFs can therefore be a flexible tool to manipulate cytosolic calcium concentrations. This tool, that can be switched on and off instantaneously, contrary to chemicals agents, can be very useful to investigate the role of calcium oscillations in cell physiology and/or to manipulate cell fate. PMID:27561994

  1. Simultaneous Sodium and Calcium Imaging from Dendrites and Axons

    PubMed Central

    Miyazaki, Kenichi

    2015-01-01

    Abstract Dynamic calcium imaging is a major technique of neuroscientists. It can reveal information about the location of various calcium channels and calcium permeable receptors, the time course, magnitude, and location of intracellular calcium concentration ([Ca2+]i) changes, and indirectly, the occurrence of action potentials. Dynamic sodium imaging, a less exploited technique, can reveal analogous information related to sodium signaling. In some cases, like the examination of AMPA and NMDA receptor signaling, measurements of both [Ca2+]i and [Na+]i changes in the same preparation may provide more information than separate measurements. To this end, we developed a technique to simultaneously measure both signals at high speed and sufficient sensitivity to detect localized physiologic events. This approach has advantages over sequential imaging because the preparation may not respond identically in different trials. We designed custom dichroic and emission filters to allow the separate detection of the fluorescence of sodium and calcium indicators loaded together into a single neuron in a brain slice from the hippocampus of Sprague-Dawley rats. We then used high-intensity light emitting diodes (LEDs) to alternately excite the two indicators at the appropriate wavelengths. These pulses were synchronized with the frames of a CCD camera running at 500 Hz. Software then separated the data streams to provide independent sodium and calcium signals. With this system we could detect [Ca2+]i and [Na+]i changes from single action potentials in axons and synaptically evoked signals in dendrites, both with submicron resolution and a good signal-to-noise ratio (S/N). PMID:26730401

  2. Simultaneous Sodium and Calcium Imaging from Dendrites and Axons.

    PubMed

    Miyazaki, Kenichi; Ross, William N

    2015-01-01

    Dynamic calcium imaging is a major technique of neuroscientists. It can reveal information about the location of various calcium channels and calcium permeable receptors, the time course, magnitude, and location of intracellular calcium concentration ([Ca(2+)]i) changes, and indirectly, the occurrence of action potentials. Dynamic sodium imaging, a less exploited technique, can reveal analogous information related to sodium signaling. In some cases, like the examination of AMPA and NMDA receptor signaling, measurements of both [Ca(2+)]i and [Na(+)]i changes in the same preparation may provide more information than separate measurements. To this end, we developed a technique to simultaneously measure both signals at high speed and sufficient sensitivity to detect localized physiologic events. This approach has advantages over sequential imaging because the preparation may not respond identically in different trials. We designed custom dichroic and emission filters to allow the separate detection of the fluorescence of sodium and calcium indicators loaded together into a single neuron in a brain slice from the hippocampus of Sprague-Dawley rats. We then used high-intensity light emitting diodes (LEDs) to alternately excite the two indicators at the appropriate wavelengths. These pulses were synchronized with the frames of a CCD camera running at 500 Hz. Software then separated the data streams to provide independent sodium and calcium signals. With this system we could detect [Ca(2+)]i and [Na(+)]i changes from single action potentials in axons and synaptically evoked signals in dendrites, both with submicron resolution and a good signal-to-noise ratio (S/N).

  3. Decline in NAD(P)H autofluorescence precedes apoptotic cell death from chemotherapy

    NASA Astrophysics Data System (ADS)

    Toms, Steven A.; Muhammad, Osman; Jackson, Heather; Lin, Wei-Chiang

    2005-11-01

    OBJECTIVE: Optical spectroscopic tools exist that allow open surgical and minimally invasive assays of intrinsic tissue optics. Optical detection of cellular and tissue viability may offer a minimally invasive way to assess tumor responsiveness to chemotherapies. We report on an optical spectroscopic change that precedes apoptotic cell death and appears related to NAD(P)H autofluorescence. METHODS: The cell lines SW 480 and U87-MG were grown in culture and treated with cisplatin 100 μg/ml and tamoxifen 10 μM, respectively. Fluorescence spectroscopy at 355 nm excitation and 460 nm emission were collected. MTS assays were used to determine cell viability. Cell lysates were analyzed for NAD(P)H concentrations by mass spectroscopy. RESULTS: Autoflourescence at 355 nm excitation and 460 nm emission declines markedly despite normalization for cell number and total protein concentration after treatment with tamoxifen or cisplatin. The autofluorescence drop precedes the loss of cell viability as measured by MTS assay. For example, the relative viability of the U87-MG cell treated with tamoxifen at hours 0, 8, 12 and 24 of treatment was 100 +/- 6, 85 +/- 6, 53 +/- 9 and 0 +/- 3. The relative fluorescence at the same time points were 100 +/- 2, 57 +/- 6, 47 +/- 3, and 0 +/- 1. TUNNEL assays confirm that cell death is via apoptosis. The key cellular fluorophore at these wavelengths is NAD(P)H. Mass spectroscopic analysis of cell lysates at these time points reveals a drop in NAD(P)H concentrations that is parallel to the loss of fluorescence signal. CONCLUSIONS: NAD(P)H autofluoresence decline precedes apoptotic cell death. This may allow the design of minimally invasive spectroscopic tools to monitor chemotherapeutic response.

  4. Behaviour of coconut mites preceding take-off to passive aerial dispersal.

    PubMed

    Melo, J W S; Lima, D B; Sabelis, M W; Pallini, A; Gondim, M G C

    2014-12-01

    For more than three decades the coconut mite Aceria guerreronis Keifer is one of the most important pests of coconut palms and has recently spread to many coconut production areas worldwide. Colonization of coconut palms is thought to arise from mites dispersing aerially after take-off from other plants within the same plantation or other plantations. The underlying dispersal behaviour of the mite at take-off, in the airborne state and after landing is largely unknown and this is essential to understand how they spread from tree to tree. In this article we studied whether take-off to aerial dispersal of coconut mites is preceded by characteristic behaviour, whether there is a correlation between the body position preceding aerial dispersal and the direction of the wind, and whether the substrate (outer surface of coconut bracts or epidermis) and the wind speed matter to the decision to take-off. We found that take-off can sometimes be preceded by a raised body stance, but more frequently take-off occurs while the mite is walking or resting on its substrate. Coconut mites that become airborne assumed a body stance that had no relation to the wind direction. Take-off was suppressed on a substrate providing food to coconut mites, but occurred significantly more frequently on the outer surface of coconut bracts than on the surface of the fruit. For both substrates, take-off frequency increased with wind speed. We conclude that coconut mites have at least some degree of control over take-off for aerial dispersal and that there is as yet no reason to infer that a raised body stance is necessary to become airborne.

  5. Gestalt perception and the decline of global precedence in older subjects.

    PubMed

    Staudinger, Markus R; Fink, Gereon R; Mackay, Clare E; Lux, Silke

    2011-01-01

    Our visual world is hierarchically organized. Hierarchical processing is frequently investigated using Navon figures (large letters made up of smaller ones). In young adults, many studies reported faster reaction times (RT) to target letters presented at the global level [i.e., global precedence (GP)]. Furthermore, an age-related decline of this GP has been reported. We tested whether deficits in perceptual grouping via Gestalt laws (Gestalt principles of Proximity and Continuity) might contribute to this decline. In a directed attention task with valid and invalid cues, 20 young (mean age 22) and 20 older (mean age 57) male subjects had to indicate whether a target letter appeared at the global or local level of a Navon figure. The number of local letters forming the global figure was modulated in 5 steps. As expected, during valid trials, young adults showed a GP that linearly increased with increasing numbers of local letters (i.e., GP enhancement). This suggests that GP is related to perceptual grouping via Gestalt laws. By contrast, the group of older subjects demonstrated no precedence effect in RT and a non-significant trend toward GP in error rates (ER). No GP enhancement with an increasing number of local elements was observed. Exploratory analysis revealed that individual insensitivity to the modulation of matrix density, as revealed by a lack of global RT acceleration, was restricted to subjects that showed an overall local precedence (LP). Because older subjects tended to more frequently display an insensitivity to matrix modulation and an LP, we conclude that deficient Gestalt detection as indicated by non-enhanced global RT might contribute to the RT-related decline of GP with age.

  6. Calcium supplement: humanity's double-edged sword.

    PubMed

    Bunyaratavej, Narong; Buranasinsup, Shutipen

    2011-10-01

    The principle aim of the present study is to investigate the dark side of calcium, pollutions in calcium preparation especially lead (Pb), mercury (Hg) and cadmium (Cd). The collected samples were the different calcium salts in the market and 18 preparations which were classified into 3 groups: Calcium carbonate salts, Chelated calcium and natural-raw calcium. All samples were analyzed for lead, cadmium and mercury by inductively Coupled Plasma Mass Spectrometry (ICP-MS) technique, in house method based on AOAC (2005) 999.10 by ICP-MS. The calcium carbonate and the natural-raw calcium in every sample contained lead at 0.023-0.407 mg/kg of calcium powder. Meanwhile, the natural-raw calcium such as oyster, coral and animal bone showed amount of lead at 0.106-0.384 mg/kg with small amounts of mercury and cadmium. The chelated calcium such as calcium gluconate, calcium lactate and calcium citrate are free of lead. PMID:22338928

  7. Paraneoplastic (non-metastatic) adrenal insufficiency preceded the onset of primary lung cancer by 12 weeks.

    PubMed

    Shantha, Ghanshyam Palamaner Subash; Kumar, Anita A; Jeyachandran, Vijay; Rajamanickam, Deepan; Bhaskar, Emmanuel; Paniker, Vinod K; Abraham, Georgi

    2009-01-01

    Clinically evident adrenal insufficiency associated with lung cancer is a rare entity. Among reported cases, adrenal insufficiency has occurred with or succeeded the primary lung cancer. Adrenal insufficiency has also been secondary to metastasis to the adrenal gland. The present report concerns a 61-year-old man, a chronic smoker, who presented to us with symptomatic adrenal insufficiency. He had no evidence of lung cancer during this visit. The primary lung cancer was only identified 12 weeks later. Additionally, his adrenals showed no evidence of metastasis. Hence his adrenal insufficiency had been a paraneoplastic manifestation of the lung cancer, and it had also preceded the primary by 12 weeks.

  8. Paraneoplastic (non-metastatic) adrenal insufficiency preceded the onset of primary lung cancer by 12 weeks

    PubMed Central

    Shantha, Ghanshyam Palamaner Subash; Kumar, Anita A; Jeyachandran, Vijay; Rajamanickam, Deepan; Bhaskar, Emmanuel; Paniker, Vinod K; Abraham, Georgi

    2009-01-01

    Clinically evident adrenal insufficiency associated with lung cancer is a rare entity. Among reported cases, adrenal insufficiency has occurred with or succeeded the primary lung cancer. Adrenal insufficiency has also been secondary to metastasis to the adrenal gland. The present report concerns a 61-year-old man, a chronic smoker, who presented to us with symptomatic adrenal insufficiency. He had no evidence of lung cancer during this visit. The primary lung cancer was only identified 12 weeks later. Additionally, his adrenals showed no evidence of metastasis. Hence his adrenal insufficiency had been a paraneoplastic manifestation of the lung cancer, and it had also preceded the primary by 12 weeks. PMID:21686682

  9. [Hyperinsulinemia as a factor preceding body mass increase in liquidators of the Chernobyl nuclear accident].

    PubMed

    Kovalenko, A N; Zueva, N A; Gerasimenko, T I; Efimov, A S

    2001-01-01

    Basal hyperinsulinemia has been recordable over several years in liquidators of the effects of Chernobyl Accident (ChAEL). There was no dependence of hyperinsulinemia on age, body mass or lenght of service of those persons having worked within the 30-km zone. The findings secured suggest to us that increase in the body mass index (BMI) in ChAEL is preceded by a rise in the blood level of insulin; there is no relatedness of the basal level of insulin in the blood to BMI.

  10. A Decrease in Temperature and Humidity Precedes Human Rhinovirus Infections in a Cold Climate

    PubMed Central

    Ikäheimo, Tiina M.; Jaakkola, Kari; Jokelainen, Jari; Saukkoriipi, Annika; Roivainen, Merja; Juvonen, Raija; Vainio, Olli; Jaakkola, Jouni J.K.

    2016-01-01

    Both temperature and humidity may independently or jointly contribute to the risk of human rhinovirus (HRV) infections, either through altered survival and spread of viruses in the environment or due to changes in host susceptibility. This study examined the relationship between short-term variations in temperature and humidity and the risk of HRV infections in a subarctic climate. We conducted a case-crossover study among conscripts (n = 892) seeking medical attention due to respiratory symptoms during their military training and identified 147 HRV cases by real-time PCR. An average temperature, a decline in daily ambient temperature and absolute humidity (AH) during the three preceding days of the onset (hazard period) and two reference periods (a week prior and after the onset) were obtained. The average daily temperature preceding HRV infections was −9.9 ± 4.9 °C and the average AH was 2.2 ± 0.9 g/m3. An average (odds ratios (OR) 1.07 (95% confidence interval (CI) 1.00–1.15)) and maximal (OR 1.08 (1.01–1.17)) change in temperature increased the risk of HRV infections by 8% per 1 °C decrease. An average (OR 1.20 (CI 1.03–1.40)) and maximal decrease (OR 1.13 (CI 0.96–1.34)) in AH increased the risk of HRV infection by 13% and 20% per 0.5 g/m3 decrease. A higher average temperature during the three preceding days was positively associated with HRV infections (OR 1.07 (CI 1.00–1.15)). A decrease rather than low temperature and humidity per se during the preceding few days increases the risk of HRV infections in a cold climate. The information is applicable to populations residing in cold climates for appropriate personal protection and prevention of adverse health effects. PMID:27598190

  11. Autoproteolysis and intramolecular dissociation of Yersinia YscU precedes secretion of its C-terminal polypeptide YscU(CC).

    PubMed

    Frost, Stefan; Ho, Oanh; Login, Frédéric H; Weise, Christoph F; Wolf-Watz, Hans; Wolf-Watz, Magnus

    2012-01-01

    Type III secretion system mediated secretion and translocation of Yop-effector proteins across the eukaryotic target cell membrane by pathogenic Yersinia is highly organized and is dependent on a switching event from secretion of early structural substrates to late effector substrates (Yops). Substrate switching can be mimicked in vitro by modulating the calcium levels in the growth medium. YscU that is essential for regulation of this switch undergoes autoproteolysis at a conserved N↑PTH motif, resulting in a 10 kDa C-terminal polypeptide fragment denoted YscU(CC). Here we show that depletion of calcium induces intramolecular dissociation of YscU(CC) from YscU followed by secretion of the YscU(CC) polypeptide. Thus, YscU(CC) behaved in vivo as a Yop protein with respect to secretion properties. Further, destabilized yscU mutants displayed increased rates of dissociation of YscU(CC)in vitro resulting in enhanced Yop secretion in vivo at 30°C relative to the wild-type strain.These findings provide strong support to the relevance of YscU(CC) dissociation for Yop secretion. We propose that YscU(CC) orchestrates a block in the secretion channel that is eliminated by calcium depletion. Further, the striking homology between different members of the YscU/FlhB family suggests that this protein family possess regulatory functions also in other bacteria using comparable mechanisms.

  12. Calcium-induced calcium release and gap junctions mediate large-scale calcium waves in olfactory ensheathing cells in situ.

    PubMed

    Stavermann, Maren; Meuth, Patrick; Doengi, Michael; Thyssen, Anne; Deitmer, Joachim W; Lohr, Christian

    2015-08-01

    Olfactory ensheathing cells (OECs) are a specialised type of glial cells, supporting axon growth and guidance during development and regeneration of the olfactory nerve and the nerve layer of the olfactory bulb. We measured calcium signalling in OECs in olfactory bulb in-toto preparations using confocal and epifluorescence microscopy and the calcium indicator Fluo-4. We identified two subpopulations of olfactory bulb OECs: OECs in the outer sublamina of the nerve layer responded to purinergic neurotransmitters such as adenosine triphosphate with calcium transients, while OECs in the inner sublamina of the nerve layer did not respond to neurotransmitters. However, the latter generated spontaneous calcium waves that covered hundreds of cells. These calcium waves persisted in the presence of tetrodotoxin and in calcium-free saline, but were abolished after calcium store depletion with cyclopiazonic acid or inositol trisphosphate receptor blockage with 2-APB. Calcium waves could be triggered by laser photolysis of caged inositol trisphosphate. Blocking purinoceptors with PPADS had no effect on calcium wave propagation, whereas blocking gap junctions with carbenoxolone or meclofenamic acid entirely suppressed calcium waves. Increasing calcium buffer capacity in OECs with NP-EGTA ("caged" Ca(2+)) prevented calcium wave generation, and laser photolysis of NP-EGTA in a small group of OECs resulted in a calcium increase in the irradiated cells followed by a calcium wave. We conclude that calcium waves in OECs can be initiated by calcium-induced calcium release via InsP3 receptors and propagate through gap junctions, while purinergic signalling is not involved.

  13. Creating Special Events

    ERIC Educational Resources Information Center

    deLisle, Lee

    2009-01-01

    "Creating Special Events" is organized as a systematic approach to festivals and events for students who seek a career in event management. This book looks at the evolution and history of festivals and events and proceeds to the nuts and bolts of event management. The book presents event management as the means of planning, organizing, directing,…

  14. Low-grade disease activity in early life precedes childhood asthma and allergy.

    PubMed

    Chawes, Bo Lund Krogsgaard

    2016-08-01

    neonates is associated with wheezing and asthma proneness, but it is unknown if such host factor also confers a risk of acute bronchiolitis, which is considered an index event of asthma persisting into school age. In paper VI, we investigated neonatal forced flow, volume, and responsiveness to methacholine in relation to occurrence of acute severe bronchiolitis at age 0-2 years. Children developing bronchiolitis had a 2.5-fold increased bronchial responsiveness as neonates (VI) suggesting a preexisting joint propensity of the airways to react adversely to common respiratory viruses and to develop asthma. This finding proposes airway hyperresponsiveness as yet another marker of low-grade disease activity among asymptomatic neonates on a trajectory towards childhood asthma. In paper VII, we examined whether neonates with impaired pulmonary capacity also had signs of systemic inflammation prior to clinical symptoms. Reduced FEV0.5 was significantly associated with elevated serum hs-CRP and other blood inflammatory markers (VII) suggesting presence of systemic low-grade inflammation from the beginning of life. Chronic low-grade inflammation is a common nominator of virtually all the major non-communicable welfare diseases (NCDs) of modernity whereof asthma and allergies are the earliest debuting disorders. The novel finding of systemic low-grade inflammation among neonates at increased risk of asthma and allergy, therefore implies that exploring the origins of asthma and allergy may also unravel disease mechanisms involved in other NCDs. In conclusion, the series of papers presented in this thesis (I-VII) evidence the presence of a pre-symptomatic disease process measurable in several body compartments, which supports the notion of low-grade disease activity in early life as a generic trait among neonates developing asthma and allergy. This hypothesis piggybacking on single biomarker assessments could be enforced and refined by applying novel global omics approaches. In

  15. Calcium signaling and cell proliferation.

    PubMed

    Pinto, Mauro Cunha Xavier; Kihara, Alexandre Hiroaki; Goulart, Vânia A M; Tonelli, Fernanda M P; Gomes, Katia N; Ulrich, Henning; Resende, Rodrigo R

    2015-11-01

    Cell proliferation is orchestrated through diverse proteins related to calcium (Ca(2+)) signaling inside the cell. Cellular Ca(2+) influx that occurs first by various mechanisms at the plasma membrane, is then followed by absorption of Ca(2+) ions by mitochondria and endoplasmic reticulum, and, finally, there is a connection of calcium stores to the nucleus. Experimental evidence indicates that the fluctuation of Ca(2+) from the endoplasmic reticulum provides a pivotal and physiological role for cell proliferation. Ca(2+) depletion in the endoplasmatic reticulum triggers Ca(2+) influx across the plasma membrane in an phenomenon called store-operated calcium entries (SOCEs). SOCE is activated through a complex interplay between a Ca(2+) sensor, denominated STIM, localized in the endoplasmic reticulum and a Ca(2+) channel at the cell membrane, denominated Orai. The interplay between STIM and Orai proteins with cell membrane receptors and their role in cell proliferation is discussed in this review.

  16. Increased expression of host iron-binding proteins precedes iron accumulation and calcification of primary lung lesions in experimental tuberculosis in the guinea pig.

    PubMed

    Basaraba, Randall J; Bielefeldt-Ohmann, Helle; Eschelbach, Ellie K; Reisenhauer, Claire; Tolnay, Airn E; Taraba, Lauren C; Shanley, Crystal A; Smith, Erin A; Bedwell, Cathy L; Chlipala, Elizabeth A; Orme, Ian M

    2008-01-01

    The growth and virulence of Mycobacterium tuberculosis depends on its ability to scavenge host iron, an essential and limited micronutrient in vivo. In this study, we show that ferric iron accumulates both intra- and extra-cellularly in the primary lung lesions of guinea pigs aerosol-infected with the H37Rv strain of M. tuberculosis. Iron accumulated within macrophages at the periphery of the primary granulomatous lesions while extra-cellular ferric iron was concentrated in areas of lesion necrosis. Accumulation of iron within primary lesions was preceded by an increase in expression of heavy chain (H) ferritin, lactoferrin and receptors for transferrin, primarily by macrophages and granulocytes. The increased expression of intra-cellular H ferritin and extra-cellular lactoferrin, more so than transferrin receptor, paralleled the development of necrosis within primary lesions. The deposition of extra-cellular ferric iron within necrotic foci coincided with the accumulation of calcium and phosphorus and other cations in the form of dystrophic calcification. Primary lung lesions from guinea pigs vaccinated with Mycobactrium bovis BCG prior to experimental infection, had reduced iron accumulation as well as H ferritin, lactoferrin and transferrin receptor expression. The amelioration of primary lesion necrosis and dystrophic calcification by BCG vaccination was coincident with the lack of extra-cellular ferric iron and lactoferrin accumulation. These data demonstrate that BCG vaccination ameliorates primary lesion necrosis, dystrophic mineralization and iron accumulation, in part by down-regulating the expression of macrophage H ferritin, lactoferrin and transferrin receptors, in vivo.

  17. Clonal expansion of CD8 T cells in the systemic circulation precedes development of ipilimumab-induced toxicities

    PubMed Central

    Subudhi, Sumit K.; Aparicio, Ana; Gao, Jianjun; Zurita, Amado J.; Araujo, John C.; Logothetis, Christopher J.; Tahir, Salahaldin A.; Korivi, Brinda R.; Slack, Rebecca S.; Vence, Luis; Emerson, Ryan O.; Yusko, Erik; Vignali, Marissa; Robins, Harlan S.; Sun, Jingjing; Allison, James P.; Sharma, Padmanee

    2016-01-01

    Immune checkpoint therapies, such as ipilimumab, induce dramatic antitumor responses in a subset of patients with advanced malignancies, but they may also induce inflammatory responses and toxicities termed immune-related adverse events (irAEs). These irAEs are often low grade and manageable, but severe irAEs may lead to prolonged hospitalizations or fatalities. Early intervention is necessary to minimize morbidities that occur with severe irAEs. However, correlative biomarkers are currently lacking. In a phase II clinical trial that treated 27 patients with metastatic prostate cancer, we aimed to test the safety and efficacy of androgen deprivation therapy plus ipilimumab. In this study, we observed grade 3 toxicities in >40% of treated patients, which led to early closure of the study. Because ipilimumab enhances T-cell responses, we hypothesized that increased clonal T-cell responses in the systemic circulation may contribute to irAEs. Sequencing of the T-cell receptor β-chains in purified T cells revealed clonal expansion of CD8 T cells, which occurred in blood samples collected before the onset of grade 2–3 irAEs. These initial results suggested that expansion of ≥55 CD8 T-cell clones preceded the development of severe irAEs. We further evaluated available blood samples from a second trial and determined that patients who experienced grade 2–3 irAEs also had expansion of ≥55 CD8 T-cell clones in blood samples collected before the onset of irAEs. We propose that CD8 T-cell clonal expansion may be a correlative biomarker to enable close monitoring and early intervention for patients receiving ipilimumab. PMID:27698113

  18. Light Induces Phosphorylation of Glucan Water Dikinase, Which Precedes Starch Degradation in Turions of the Duckweed Spirodela polyrhiza12

    PubMed Central

    Reimann, Rezarta; Hippler, Michael; Machelett, Bernd; Appenroth, Klaus-J.

    2004-01-01

    Degradation of storage starch in turions, survival organs of Spirodela polyrhiza, is induced by light. Starch granules isolated from irradiated (24 h red light) or dark-stored turions were used as an in vitro test system to study initial events of starch degradation. The starch-associated pool of glucan water dikinase (GWD) was investigated by two-dimensional gel electrophoresis and by western blotting using antibodies raised against GWD. Application of this technique allowed us to detect spots of GWD, which are light induced and absent on immunoblots prepared from dark-adapted plants. These spots, showing increased signal intensity following incubation of the starch granules with ATP, became labeled by randomized [βγ-33P]ATP but not by [γ-33P]ATP and were removed by acid phosphatase treatment. This strongly suggests that they represent a phosphorylated form(s) of GWD. The same light signal that induces starch degradation was thus demonstrated for the first time to induce autophosphorylation of starch-associated GWD. The in vitro assay system has been used to study further effects of the light signal that induces autophosphorylation of GWD and starch degradation. In comparison with starch granules from dark-adapted plants, those from irradiated plants showed increase in (1) binding capacity of GWD by ATP treatment decreased after phosphatase treatment; (2) incorporation of the β-phosphate group of ATP into starch granules; and (3) rate of degradation of isolated granules by starch-associated proteins, further enhanced by phosphorylation of starch. The presented results provide evidence that autophosphorylation of GWD precedes the initiation of starch degradation under physiological conditions. PMID:15122031

  19. The effect of preceding wintertime Arctic polar vortex on springtime NDVI patterns in boreal Eurasia, 1982-2015

    NASA Astrophysics Data System (ADS)

    Li, Jing; Fan, Ke; Xu, Jianjun; Powell, Alfred M.; Kogan, Felix

    2016-08-01

    The polar vortex is implicated in certain cold events in boreal Eurasia and has a further influence on land surface properties (e.g., vegetation and snow) during spring. The Normalized Difference Vegetation Index (NDVI) can be used as a proxy of land surface responses to climate changes to a certain degree. In this study, we demonstrate the significant correlation between preceding wintertime Arctic polar vortex intensity (WAPVI) and springtime NDVI (SNDVI) over a 34-year period (1982-2015) in boreal Eurasia (50°-75°N, 0°-150°E). Results show that a positive phase of WAPVI tends to increase the SNDVI in Europe and Lake Baikal, but causes a significant decrease in Siberia; the physical mechanisms involved in this relationship are then investigated. A positive phase of WAPVI leads to anomalies in surface air temperature and rainfall over Eurasia, which then induces a significant decrease in snow cover and snow depth in Europe and Lake Baikal and an increase of snow depth in Siberia. The colder ground temperature in Siberia during spring is considered responsible for the stronger snow depth and weaker vegetation growth in this region. The weaker and thinner snow cover in Europe and Baikal produces a decrease in albedo and an increase in heat. Thin snow melts fast in the following spring and land releases more heat to the atmosphere; consequently, warm and moist land surface facilitates vegetation growth in Europe and the Baikal regions during positive WAPVI years. In addition, WAPVI can induce sea surface temperature (SST) anomalies in the North Atlantic, which displays a tripole pattern similar to that of the empirical mode pattern in winter. Furthermore, the SST anomalous pattern persisting from winter to spring can trigger a stationary wave-train propagating from west to east in boreal Eurasia, with "negative-positive-negative-positive" geopotential height anomalies, which further exerts an impact on vegetation growth through modulation of the heat balance.

  20. The effect of variable calcium and very low calcium diets on human calcium metabolism. Ph.D. Thesis. Final Report

    NASA Technical Reports Server (NTRS)

    Chu, J.

    1971-01-01

    The effects of a very low calcium diet, with variable high and low protein intake, on the dynamics of calcium metabolism and the mechanism of calciuretics, are examined. The experiment, using male subjects, was designed to study the role of intestinal calcium absorption on urinary calcium excretion, and the rate of production of endogeneously secreted calcium in the gastrointestinal tract. The study showed an average of 70% fractional absorption rate during very low calcium intake, and that a decrease in renal tubular reabsorption of calcium is responsible for calciuretic effects of high protein intake. The study also indicates that there is a tendency to develop osteoporosis after long periods of low calcium intake, especially with a concurrent high protein intake.

  1. Nocturnal respiration of lichens in their natural habitat is not affected by preceding diurnal net photosynthesis.

    PubMed

    Lange, Otto L; Green, T G Allan

    2006-06-01

    Dark respiration (DR) of lichens is reported to be higher in species with a high photosynthetic potential (suggesting a metabolic maintenance cost effect) and also, often in laboratory studies, transiently after photosynthesis (suggesting a substrate-driven effect). We investigated the occurrence of the latter, the effect of diurnal net photosynthesis (NP) on subsequent nocturnal DR, under natural temperate climate conditions in the chlorolichens Lecanora muralis and Cladonia convoluta and the cyanolichen Collema cristatum. Data sets totalling 15 months, 106 and 113 days, respectively, were obtained from automatic cuvettes that continually measured CO2 exchange and ambient conditions at 30 min intervals. For each 24 h period (sunrise to following sunrise), several measures of NP and DR were extracted, including maximal and mean rates and daily sums. No statistically significant correlations between the various measures of DR and preceding NP were found for L. muralis, only one weak correlation for Co. cristatum (the means of DR and NP) and three for Cl. convoluta (sums and means of DR and NP). It is proposed that even these significant correlations are actually a result of embedded codependencies between NP, DR and thallus water content. Overall it is concluded that no substrate-driven dependency of DR on preceding NP under natural conditions could be recognised. The periods of desiccation that often occur between the NP and following DR as well as the wide range of combinations of conditions would certainly contribute to this lack of relationship.

  2. Peripheral and central neuronal ATF3 precedes CD4+ T-cell infiltration in EAE.

    PubMed

    Frezel, Noémie; Sohet, Fabien; Daneman, Richard; Basbaum, Allan I; Braz, Joao M

    2016-09-01

    Experimental allergic encephalomyelitis (EAE), an animal model of multiple sclerosis produced by immunization with myelin oligodendrocyte glycoprotein (MOG) and adjuvants, results from profound T-cell mediated CNS demyelination. EAE is characterized by progressive, ascending motor dysfunction and symptoms of ongoing pain and hypersensitivity, in some cases preceding or concomitant with the motor deficits. In this regard, the EAE model mimics major features of multiple sclerosis, where a central neuropathic pain state is common. Although the latter condition is presumed to arise from a CNS loss of inhibitory controls secondary to the demyelination, dysfunction of sensory neurons may also contribute. Based on our previous studies that demonstrated the utility of monitoring expression of activating transcription factor 3 (ATF3), a sensitive marker of injured sensory neurons, here we followed both ATF3 and CD4+ T cells invasion of sensory ganglia (as well as the CNS) at different stages of the EAE model. We found that ATF3 is induced in peripheral sensory ganglia and brainstem well before the appearance of motor deficits. Unexpectedly, the ATF3 induction always preceded T cell infiltration, typically in adjacent, but non-overlapping regions. Surprisingly, control administration of the pertussis toxin and/or Complete Freund's adjuvants, without MOG, induced ATF3 in sensory neurons. In contrast, T cell infiltration only occurred with MOG. Taken together, our results suggest that the clinical manifestations in the EAE result not only from central demyelination but also from neuronal stress and subsequent pathophysiology of sensory neurons. PMID:27343802

  3. Aseismic Slips Preceding Ruptures Assumed for Anomalous Seismicities and Crustal Deformations

    NASA Astrophysics Data System (ADS)

    Ogata, Y.

    2007-12-01

    If aseismic slips occurs on a fault or its deeper extension, both seismicity and geodetic records around the source should be affected. Such anomalies are revealed to have occurred during the last several years leading up to the October 2004 Chuetsu Earthquake of M6.8, the March 2007 Noto Peninsula Earthquake of M6.9, and the July 2007 Chuetsu-Oki Earthquake of M6.8, which occurred successively in the near-field, central Japan. Seismic zones of negative and positive increments of the Coulomb failure stress, assuming such slips, show seismic quiescence and activation, respectively, relative to the predicted rate by the ETAS model. These are further supported by transient crustal movement around the source preceding the rupture. Namely, time series of the baseline distance records between a numbers of the permanent GPS stations deviated from the predicted trend, with the trend of different slope that is basically consistent with the horizontal displacements of the stations due to the assumed slips. References Ogata, Y. (2007) Seismicity and geodetic anomalies in a wide area preceding the Niigata-Ken-Chuetsu Earthquake of October 23, 2004, central Japan, J. Geophys. Res. 112, in press.

  4. Investigations of the precedence effect in budgerigars: The perceived location of auditory images

    NASA Astrophysics Data System (ADS)

    Dent, Micheal L.; Dooling, Robert J.

    2003-04-01

    The perceived location of auditory images has been recently studied in budgerigars [Dent and Dooling, J. Acoust. Soc. Am. 113, 2146-2158 (2003)]. Those results suggested that budgerigars (Melopsittacus undulatus) perceive precedence effect stimuli in a manner similar to humans and other animals. Here we extend those experiments to include the effects of intensity on the perceived location of auditory images and the perceived location of paired stimuli from multiple locations in space. We measured the abilities of budgerigars to discriminate between paired stimuli separated in time, intensity, and/or location. Increasing the intensity of a lag stimulus disrupted localization dominance. Budgerigars also perceived simultaneously presented (away from the midline) stimuli as very similar to a single sound presented from the midline, much like the phantom image reported in humans. The perception of paired stimuli from one side of the head versus two sides of the head was also examined and showed that the spatial cues available in these stimuli are important and that echoes are not perceptually inaccessible during localization dominance conditions. The results from these experiments add further data showing the precedence effect in budgerigars is similar to that found in humans and other animals.

  5. Male and female effects on sperm precedence in the giant sperm species Drosophila bifurca.

    PubMed

    Luck, Nathalie; Dejonghe, Béatrice; Fruchard, Stéphane; Huguenin, Sophie; Joly, Dominique

    2007-07-01

    Sperm competition is expected to be a driving force in sexual selection. In internally fertilized organisms, it occurs when ejaculates from more than one male are present simultaneously within the female's reproductive tract. It has been suggested that greater sperm size may improve the competitive ability of sperm, but studies provide contradictory results depending on the species. More recently, the role of females in the evolution of sperm morphology has been pointed out. We investigate here the male and female effects that influence sperm precedence in the giant sperm species, Drosophila bifurca Patterson & Wheeler. Females were mated with two successive males, and the paternity outcomes for both males were analyzed after determining sperm transfer and storage. We found very high values of last male sperm precedence, suggesting a strong interaction between rival sperm. However, the data also indicate high frequencies of removal of the sperm of the first male from the female reproductive tract prior to any interaction with the second male. This implies that successful paternity depends mainly on successful sperm storage. Knowing what happens to the sperm within females appears to be a prerequisite for disentangling post-copulatory sexual interactions between males and females.

  6. HIGH-RESOLUTION SIMULATIONS OF CONVECTION PRECEDING IGNITION IN TYPE Ia SUPERNOVAE USING ADAPTIVE MESH REFINEMENT

    SciTech Connect

    Nonaka, A.; Aspden, A. J.; Almgren, A. S.; Bell, J. B.; Zingale, M.; Woosley, S. E.

    2012-01-20

    We extend our previous three-dimensional, full-star simulations of the final hours of convection preceding ignition in Type Ia supernovae to higher resolution using the adaptive mesh refinement capability of our low Mach number code, MAESTRO. We report the statistics of the ignition of the first flame at an effective 4.34 km resolution and general flow field properties at an effective 2.17 km resolution. We find that off-center ignition is likely, with radius of 50 km most favored and a likely range of 40-75 km. This is consistent with our previous coarser (8.68 km resolution) simulations, implying that we have achieved sufficient resolution in our determination of likely ignition radii. The dynamics of the last few hot spots preceding ignition suggest that a multiple ignition scenario is not likely. With improved resolution, we can more clearly see the general flow pattern in the convective region, characterized by a strong outward plume with a lower speed recirculation. We show that the convective core is turbulent with a Kolmogorov spectrum and has a lower turbulent intensity and larger integral length scale than previously thought (on the order of 16 km s{sup -1} and 200 km, respectively), and we discuss the potential consequences for the first flames.

  7. The effect of an additional reflection in a precedence effect experiment

    PubMed Central

    Goupell, Matthew J.; Yu, Gongqiang; Litovsky, Ruth Y.

    2012-01-01

    Studies on the precedence effect typically utilize a two-source paradigm, which is not realistic relative to real world situations where multiple reflections exist. A step closer to multiple-reflection situations was studied using a three-source paradigm. Discrimination of interaural time differences (ITDs) was measured for one-, two-, and three-source stimuli, using clicks presented over headphones. The ITD was varied in either the first, second, or the third source. The inter-source intervals ranged from 0–130 ms. A perceptual weighting model was extendedto incorporate the three-source stimuli and used to interpret the data. The effect of adding a third source could mostly, but not entirely, be understood by the interaction of effects observed in the precedence effect with two sources. Specifically, for delays between 1 and 8 ms, the ITD information of prior sources was typically weighted more heavily than subsequent sources. For delays greater than 8 ms, subsequent sources were typically weighted slightly more heavily than prior sources. However, there were specific conditions that showed a more complex interaction between the sources. These findings suggest that the two-source paradigm provides a strong basis for understanding how the auditory system processes reflections in spatial hearing tasks. PMID:22501073

  8. The relationship between congenital cardiovascular malformations and spontaneous abortion in preceding pregnancy.

    PubMed

    Sheiner, E; Katz, M; Fraser, D; Gohar, J; Carmi, R

    1998-04-01

    Previous studies have shown an increased frequency of spontaneous abortions in the pregnancy preceding a fetus or a newborn with neural tube defect (NTD) compared with a normal newborn. One explanation of this observation is the trophoblastic cell rest hypothesis put forward by Knox and Clarke, suggesting a teratogenic interaction between the developing embryo and pathological remnants of a previous pregnancy. The other explanation is that the previously lost fetus was also affected with neural tube defect. The aim of this study was to verify whether this observation is also valid for congenital cardiovascular malformations (CCVM). Demographic and obstetric data of 99 mothers (58 Jewish and 41 Bedouin) of newborns who died in the neonatal period from isolated CCVM were compared with those of 103 mothers (48 Jewish and 55 Bedouin) of newborns who died of congenital defects other than NTD and CCVM. Spontaneous abortions in the preceding pregnancy were found in 32% of the cases with CCVM compared with 14% of cases with other defects (ODs) (P=0.0012; odds ratio=3.1, 95% confidence interval 1.5-6.4). This significant difference was independent of maternal age and number of pregnancies or deliveries. No difference was found between Jews and Bedouins. As there is no indication in the literature that fetuses with isolated CCVM tend to be spontaneously aborted, our findings are more supportive of the trophoblastic cell rest theory. PMID:9620563

  9. The Chicken or the Egg: Examining Temporal Precedence Among Attitudes, Injunctive Norms, and College Student Drinking

    PubMed Central

    Lewis, Melissa A.; Litt, Dana M.; Neighbors, Clayton

    2015-01-01

    Objective: The present study was designed to test for projection, conformity, or reciprocal associations among attitudes, injunctive norms, and drinking. Assuming that these constructs are not independent, we proposed three possible trajectories. A conformity model would suggest that injunctive norms should temporally precede drinking or attitudes. Alternatively, a projection model would suggest that attitudes or alcohol use would precede injunctive norms. Furthermore, by examining the processes over three time points, the current study would also examine whether both conformity and projection processes were at work, indicating reciprocal relationships. Method: participants included 249 college students (63.1% female), who participated as a control group in a larger intervention trial. Structural equation modeling was used to examine cross-sectional and prospective associations among injunctive norms, attitudes, and drinking across each of the three time points. Results: Findings demonstrated three significant cross-lagged associations. Injunctive norms at Time 1 was significantly associated with drinking at Time 2 (conformity), and both attitudes and drinking at Time 2 were significantly associated with injunctive norms at Time 3 (projection). The pattern of cross-lagged associations suggested one meaningful indirect pathway, from Time 1 injunctive norms to Time 2 drinking to Time 3 injunctive norms (reciprocal association). Conclusions: The present study suggests that both the conformity and the projection processes seem to be important and evident for college student drinking when considering injunctive norms and drinking over time. Interventions that focus on both conformity and projection may be particularly effective at reducing longer-term alcohol use. PMID:26098035

  10. Elevated prolactin levels immediately precede decisions to babysit by male meerkat helpers.

    PubMed

    Carlson, Anne A; Russell, Andrew F; Young, Andrew J; Jordan, Neil R; McNeilly, Alan S; Parlow, Al F; Clutton-Brock, Tim

    2006-06-01

    Recent studies suggest that decisions to care for the offspring of others in societies of cooperative vertebrates may have a hormonal basis. The crucial question of whether changes in hormone levels immediately precede or merely follow bouts of offspring care, however, remains largely unanswered. Here, we show that in wild groups of cooperatively breeding meerkats, male helpers that decided to babysit for the day had significantly higher levels of prolactin, coupled with lower levels of cortisol, before initiating a babysitting session compared with similarly aged individuals that decided to forage. In addition, these hormonal differences disappeared over the course of the day, suggesting that hormone levels changed in a fundamentally different way in meerkats that babysat versus those that foraged. In contrast, long-term contributions to babysitting were not significantly associated with plasma levels of prolactin, cortisol, or testosterone in individual male helpers. Our results show, for the first time, that elevated levels of prolactin may immediately precede bouts of helping behavior but differ from recent findings on the same study population in which plasma levels of cortisol, but not prolactin, were significantly and positively associated with rates of pup feeding by male helpers. Together, these results lend significant weight to the idea that decisions to help in cooperative vertebrates have a hormonal basis, although different hormones appear to be associated with different types of care.

  11. Application of Convergence Confinement Analysis to the study of preceding displacement of a squeezing rock tunnel

    NASA Astrophysics Data System (ADS)

    Kitagawa, T.; Kumeta, T.; Ichizyo, T.; Soga, S.; Sato, M.; Yasukawa, M.

    1991-01-01

    This paper deals with a study on the geomechanical behavior of the rock mass around the tunnel. The Convergence Confinement Analysis is one of the most appropriate way to estimate this behavior. Elasto-plastic models proposed by Hoek and Brown, Egger and Kastner were adopted in this study. Measurements of the preceding displacement were performed in a road tunnel in Japan, the geology of which is Neogene squeezing mudstone. The measured data was compared with the results of Convergence Confinement Analysis. The preceding displacement was about 40% against the upper bench face converged displacement and 17% against the final converged displacement. Meanwhile, it increased drastically in lower bench excavation step. Back analysis was also executed to calculate the extension of the plastic zone of the rock mass, which was half of that estimated by Convergence Confinement Analysis in upper bench excavation step. But, in lower bench excavation step, the results of the two analyses were very similar. The support pressure and support stiffness were also calculated.

  12. Effects of Prediction and Contextual Support on Lexical Processing: Prediction takes Precedence

    PubMed Central

    Brothers, Trevor; Swaab, Tamara Y.; Traxler, Matthew J.

    2014-01-01

    Readers may use contextual information to anticipate and pre-activate specific lexical items during reading. However, prior studies have not clearly dissociated the effects of accurate lexical prediction from other forms of contextual facilitation such as plausibility or semantic priming. In this study, we measured electrophysiological responses to predicted and unpredicted target words in passages providing varying levels of contextual support. This method was used to isolate the neural effects of prediction from other potential contextual influences on lexical processing. While both prediction and discourse context influenced ERP amplitudes within the time range of the N400, the effects of prediction occurred much more rapidly, preceding contextual facilitation by approximately 100ms. In addition, a frontal, post-N400 positivity (PNP) was modulated by both prediction accuracy and the overall plausibility of the preceding passage. These results suggest a unique temporal primacy for prediction in facilitating lexical access. They also suggest that the frontal PNP may index the costs of revising discourse representations following an incorrect lexical prediction. PMID:25497522

  13. Elevated prolactin levels immediately precede decisions to babysit by male meerkat helpers.

    PubMed

    Carlson, Anne A; Russell, Andrew F; Young, Andrew J; Jordan, Neil R; McNeilly, Alan S; Parlow, Al F; Clutton-Brock, Tim

    2006-06-01

    Recent studies suggest that decisions to care for the offspring of others in societies of cooperative vertebrates may have a hormonal basis. The crucial question of whether changes in hormone levels immediately precede or merely follow bouts of offspring care, however, remains largely unanswered. Here, we show that in wild groups of cooperatively breeding meerkats, male helpers that decided to babysit for the day had significantly higher levels of prolactin, coupled with lower levels of cortisol, before initiating a babysitting session compared with similarly aged individuals that decided to forage. In addition, these hormonal differences disappeared over the course of the day, suggesting that hormone levels changed in a fundamentally different way in meerkats that babysat versus those that foraged. In contrast, long-term contributions to babysitting were not significantly associated with plasma levels of prolactin, cortisol, or testosterone in individual male helpers. Our results show, for the first time, that elevated levels of prolactin may immediately precede bouts of helping behavior but differ from recent findings on the same study population in which plasma levels of cortisol, but not prolactin, were significantly and positively associated with rates of pup feeding by male helpers. Together, these results lend significant weight to the idea that decisions to help in cooperative vertebrates have a hormonal basis, although different hormones appear to be associated with different types of care. PMID:16527276

  14. [Submucosal Partial-turbinectomy (SPT) Preceding an Endoscopic Sinus Surgery (ESS) Procedure].

    PubMed

    Hirai, Tomohisa; Fukushima, Noriyuki; Miyahara, Nobuyuki; Miyoshi, Ayako; Ariki, Masahiko

    2015-07-01

    Preceding a endoscopic sinus surgery (ESS), we have proposed performing a submucosal partial-turbinectomy (SPT) which removes a part of the inferior nasal concha bone attached to maxillary sinus with an antrostomy. By this method, we could not only make a large antrostomy but also obtain good maneuverability by opening the middle nasal meatus in ESS. We performed SPT preceding ESS in 140 cases (261 sides) between January 2012 and June 2014. The stenosis rates of the middle nasal meatus were 14.2% (37 sides from 261 sides) in one month, 7.4% (18 sides from 243 sides) in three months and 3.7% (6 sides from 163 sides) in 6 months after surgery. The closing rates of the antrostomy were 1.5% (4 sides from 261 sides) in one month, 2.9% (7 sides from 243 sides) in three months and 6.7% (11 sides from 163 sides) in 6 months after surgery. We considered that the SPT method would contribute to secure sufficient ventilation routes for wound healing of sinusitis following surgery on the mucous membrane. In addition, the SPT method has merit from the point of deceasing risks of atrophic rhinitis and empty nose syndrome by preserving most of the inferior nasal concha.

  15. AIRS Remote Sensing of Ammonia Species Preceding the Alaska Fire of 2004 Compared to Ground Monitoring in New York City

    NASA Astrophysics Data System (ADS)

    Padilla, D.; Steiner, J.; Menzel, P.

    2008-05-01

    Ammonia and ammonium sulfate are common industrial and agricultural byproducts. A widespread pollution event recorded by the Environmental Protection Agency July 2004 in the northeastern United States was overprinted and replaced in New York City by a down-trending of a smoke-laden aerosol tracked from the 2004 Alaska fire. Background subtraction of the absorption bands for ammonia (A) using the AIRS band at 966 cm-1 identifies a possible ammonia-rich plume that followed a westerly transect from the Midwest to New York City. The transition from ammonium sulfate (AS)-dominated to organic-derived carbon is documented at CCNY/NYC using x-ray diffraction (XRD) analysis of ribbons from an Environmental Beta Attenuation Monitor. XRD peaks are consistent with crystalline PM2.5 AS increasing dramatically over the interval July 17-21, being replaced by smoke particulates on July 22. Scanning electron microscope and energy dispersive analysis (SEM/EDS) of the smoke particulates show significant potassium and calcium enrichment in the complex ash, as do analysis of fractions of the ribbon analyzed by induced coupled plasma emission (ICP). This conforms to laboratory investigation of the byproducts of the combustion of pine and fir that show similar K- and Ca-enrichment. The laboratory data and the AIRS remote sensing measurements are combined with the MODIS Aerosol Optical Depth product to develop a method for monitoring industrial and agricultural ammonia-concentrated air masses for climate modeling.

  16. Calcium hydroxylapatite for facial rejuvenation.

    PubMed

    Berlin, Alexander; Cohen, Joel L; Goldberg, David J

    2006-09-01

    Porous calcium hydroxylapatite has been used in otolaryngology, dentistry and radiology for many years. Currently, calcium hydroxylapatite is gaining popularity for facial esthetics in the form of the product Radiesse (San Mateo, CA). Although Radiesse is not yet approved in the United States for cosmetic use, it is being used off-label by an increasing number of dermatologists and plastic surgeons for facial soft-tissue augmentation. Preliminary clinical and histologic studies have shown safety, efficacy and durability in various esthetic applications including the nasolabial folds and HIV lipoatrophy.

  17. Calcium supplementation during sepsis exacerbates organ failure and mortality via calcium/calmodulin-dependent protein kinase kinase (CaMKK) signaling

    PubMed Central

    Collage, Richard D.; Howell, Gina M.; Zhang, Xianghong; Stripay, Jennifer L.; Lee, Janet S.; Angus, Derek C.; Rosengart, Matthew R.

    2013-01-01

    Background Calcium plays an essential role in nearly all cellular processes. As such, cellular and systemic calcium concentrations are tightly regulated. During sepsis derangements in such tight regulation frequently occur, and treating hypocalcemia with parenteral calcium administration remains the current practice guideline. Objective We investigated whether calcium administration worsens mortality and organ dysfunction using an experimental murine model of sepsis and explored the mechanistic role of the family of calcium/calmodulin-dependent protein kinases in mediating these physiologic effects. To highlight the biological relevance of these observations, we conducted a translational study of the association between calcium administration, organ dysfunction and mortality among a cohort of critically ill septic ICU patients Design Prospective, randomized controlled experimental murine study. Observational clinical cohort analysis. Setting University research laboratory. Eight ICUs at a tertiary care center. Patients 870 septic ICU patients. Subjects C57BL/6 and CaMKK−/− mice. Interventions Mice underwent cecal ligation and puncture polymicrobial sepsis and were administered calcium chloride (0.25 or 0.25 mg/kg) or normal saline. Measurements and Main Results Administering calcium chloride to septic C57BL/6 mice heightened systemic inflammation and vascular leak, exacerbated hepatic and renal dysfunction, and increased mortality. These events were significantly attenuated in CaMKK−/− mice. In a risk–adjusted analysis of septic patients, calcium administration was associated with an increased risk of death, OR 1.92 (95% CI 1.00–3.68, p=0.049), a significant increase in the risk of renal dysfunction, OR 4.74 (95% CI 2.48–9.08, p<0.001), and a significant reduction in ventilator free days, mean decrease 3.29 days (0.50–6.08 days, p=0.02). Conclusions Derangements in calcium homeostasis occur during sepsis that are sensitive to calcium administration

  18. The effect of calcium gluconate and other calcium supplements as a dietary calcium source on magnesium absorption in rats.

    PubMed

    Chonan, O; Takahashi, R; Yasui, H; Watanuki, M

    1997-01-01

    The effects of commercially available calcium supplements (calcium carbonate, calcium gluconate, oyster shell preparation and bovine bone preparation) and gluconic acid on the absorption of calcium and magnesium were evaluated for 30 days in male Wistar rats. There were no differences in the apparent absorption ratio of calcium among rats fed each calcium supplement; however, the rats fed the calcium gluconate diet had a higher apparent absorption ratio of magnesium than the rats fed the other calcium supplements. Dietary gluconic acid also more markedly stimulated magnesium absorption than the calcium carbonate diet, and the bone (femur and tibia) magnesium contents of rats fed the gluconic acid diet were significantly higher than those of the rats fed the calcium carbonate diet. Furthermore, the weight of cecal tissue and the concentrations of acetic acid and butyric acid in cecal digesta of rats fed the calcium gluconate diet or the gluconic acid diet were significantly increased. We speculate that the stimulation of magnesium absorption in rats fed the calcium gluconate diet is a result of the gluconic acid component and the effect of gluconic acid on magnesium absorption probably results from cecal hypertrophy, magnesium solubility in the large intestine and the effects of volatile fatty acids on magnesium absorption.

  19. Extra-intestinal calcium handling contributes to normal serum calcium levels when intestinal calcium absorption is suboptimal.

    PubMed

    Lieben, Liesbet; Verlinden, Lieve; Masuyama, Ritsuko; Torrekens, Sophie; Moermans, Karen; Schoonjans, Luc; Carmeliet, Peter; Carmeliet, Geert

    2015-12-01

    The active form of vitamin D, 1,25(OH)2D, is a crucial regulator of calcium homeostasis, especially through stimulation of intestinal calcium transport. Lack of intestinal vitamin D receptor (VDR) signaling does however not result in hypocalcemia, because the increased 1,25(OH)2D levels stimulate calcium handling in extra-intestinal tissues. Systemic VDR deficiency, on the other hand, results in hypocalcemia because calcium handling is impaired not only in the intestine, but also in kidney and bone. It remains however unclear whether low intestinal VDR activity, as observed during aging, is sufficient for intestinal calcium transport and for mineral and bone homeostasis. To this end, we generated mice that expressed the Vdr exclusively in the gut, but at reduced levels. We found that ~15% of intestinal VDR expression greatly prevented the Vdr null phenotype in young-adult mice, including the severe hypocalcemia. Serum calcium levels were, however, in the low-normal range, which may be due to the suboptimal intestinal calcium absorption, renal calcium loss, insufficient increase in bone resorption and normal calcium incorporation in the bone matrix. In conclusion, our results indicate that low intestinal VDR levels improve intestinal calcium absorption compared to Vdr null mice, but also show that 1,25(OH)2D-mediated fine-tuning of renal calcium reabsorption and bone mineralization and resorption is required to maintain fully normal serum calcium levels.

  20. Preceding infection as an important risk factor for ischaemic brain infarction in young and middle aged patients

    PubMed Central

    Syrjänen, Jaana; Valtonen, Ville V; Iivanainen, Matti; Kaste, Markku; Huttunen, Jussi K

    1988-01-01

    The role of preceding infection as a risk factor for ischaemic stroke was investigated in a case-control study of 54 consecutive patients under 50 years of age with brain infarction and 54 randomly selected controls from the community matched for sex and age. Information about previous illnesses, smoking, consumption of alcohol, and use of drugs was taken. A blood sample was analysed for standard biochemical variables and serum cholesterol, high density lipoprotein cholesterol, triglyceride, and fasting blood glucose concentrations determined. Titres of antimicrobial antibodies against various bacteria, including Staphylococcus, Streptococcus, Yersinia, and Salmonella and several viruses were determined. Febrile infection was found in patients during the month before the brain infarction significantly more often than in controls one month before their examination (19 patients v three controls; estimated relative risk 9·0 (95% confidence interval 2·2 to 80·0)). The most common preceding febrile infection was respiratory infection (80%). Infections preceding brain infarction were mostly of bacterial origin based on cultural, serological, and clinical data. In conditional logistic regression analysis for matched pairs the effect of preceding febrile infection remained significant (estimated relative risk 14·5 (95% confidence interval 1·9 to 112·3)) when tested with triglyceride concentration, hypertension, smoking, and preceding intoxication with alcohol. Although causality cannot be inferred from these data and plausible underlying mechanisms remain undetermined, preceding febrile infection may play an important part in the development of brain infarction in young and middle aged patients. PMID:3132245

  1. 21 CFR 582.5223 - Calcium pyrophosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5223 Calcium pyrophosphate. (a) Product. Calcium pyrophosphate. (b) Conditions of...

  2. 21 CFR 582.5212 - Calcium pantothenate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5212 Calcium pantothenate. (a) Product. Calcium pantothenate. (b) Conditions of use....

  3. 21 CFR 582.5212 - Calcium pantothenate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5212 Calcium pantothenate. (a) Product. Calcium pantothenate. (b) Conditions of use....

  4. 21 CFR 582.5212 - Calcium pantothenate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5212 Calcium pantothenate. (a) Product. Calcium pantothenate. (b) Conditions of use....

  5. 21 CFR 582.5230 - Calcium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b) Conditions of use. This...

  6. 21 CFR 582.5217 - Calcium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  7. 21 CFR 582.5223 - Calcium pyrophosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5223 Calcium pyrophosphate. (a) Product. Calcium pyrophosphate. (b) Conditions of...

  8. 21 CFR 582.5195 - Calcium citrate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5195 Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This...

  9. 21 CFR 582.5217 - Calcium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  10. 21 CFR 582.5223 - Calcium pyrophosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5223 Calcium pyrophosphate. (a) Product. Calcium pyrophosphate. (b) Conditions of...

  11. 21 CFR 582.5212 - Calcium pantothenate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5212 Calcium pantothenate. (a) Product. Calcium pantothenate. (b) Conditions of use....

  12. 21 CFR 582.5230 - Calcium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b) Conditions of use. This...

  13. 21 CFR 582.5191 - Calcium carbonate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  14. 21 CFR 582.5191 - Calcium carbonate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  15. 21 CFR 582.5217 - Calcium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  16. 21 CFR 582.5195 - Calcium citrate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5195 Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This...

  17. 21 CFR 582.5212 - Calcium pantothenate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5212 Calcium pantothenate. (a) Product. Calcium pantothenate. (b) Conditions of use....

  18. 21 CFR 582.5230 - Calcium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b) Conditions of use. This...

  19. 21 CFR 582.5195 - Calcium citrate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5195 Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This...

  20. 21 CFR 582.5195 - Calcium citrate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5195 Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This...

  1. 21 CFR 582.5217 - Calcium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  2. 21 CFR 582.5191 - Calcium carbonate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  3. 21 CFR 582.5217 - Calcium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  4. 21 CFR 582.5195 - Calcium citrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5195 Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This...

  5. 21 CFR 582.5223 - Calcium pyrophosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5223 Calcium pyrophosphate. (a) Product. Calcium pyrophosphate. (b) Conditions of...

  6. 21 CFR 582.5191 - Calcium carbonate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  7. 21 CFR 582.5191 - Calcium carbonate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  8. 21 CFR 582.5230 - Calcium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b) Conditions of use. This...

  9. 21 CFR 582.5223 - Calcium pyrophosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5223 Calcium pyrophosphate. (a) Product. Calcium pyrophosphate. (b) Conditions of...

  10. 21 CFR 582.5230 - Calcium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b) Conditions of use. This...

  11. Principles of calcium-based biomineralization.

    PubMed

    Feng, Qingling

    2011-01-01

    The chapter provides some basic information on the formation principles of calcium carbonate in biological systems in marine environment in the point of view of materials science in order to provide strategies for biomimetic design and preparation of new functional materials. Many researchers try to explain the principles of biomineralization and get some valuable conclusions. This chapter introduces some calcium-based biominerals in aquatic organisms which mainly include calcium carbonate and calcium phosphate. Then it gives a presentation of the hierarchical structure of calcium carbonate-based and calcium phosphate-based biominerals, e.g., mollusc shell, pearl, carp otolith, tooth, and bone. Moreover, the chapter explains the principles of calcium carbonate mineralization from the aspects of the effects of additives and templates; it also gives some explanations to the principles of calcium phosphate mineralization. PMID:21877266

  12. Calcium Supplements May Not Be Heart Healthy

    MedlinePlus

    ... and noted that other data has suggested that calcium supplements might also raise a patient's odds for kidney stones. Because of this risk and the potential risk for heart disease, "I only recommend to my patients calcium in ...

  13. Decalcification of calcium polycarbophil in rats.

    PubMed

    Yamada, T; Saito, T; Takahara, E; Nagata, O; Tamai, I; Tsuji, A

    1997-03-01

    The in vivo decalcification of calcium polycarbophil was examined. The decalcification ratio of [45Ca]calcium polycarbophil in the stomach after oral dosing to rats was more than 70% at each designated time and quite closely followed in the in vitro decalcification curve, indicating that the greater part of the calcium ion is released from calcium polycarbophil under normal gastric acidic conditions. The residual radioactivity in rat gastrointestine was nearly equal to that after oral administration of either [45Ca]calcium chloride + polycarbophil. The serum level of radioactivity was nearly equal to that after oral dosing of [45Ca]calcium lactate. These results indicate that the greater part of orally administered calcium polycarbophil released calcium ions to produce polycarbophil in vivo.

  14. Dairy Dilemma: Are You Getting Enough Calcium?

    MedlinePlus

    ... Dairy Dilemma Dairy Dilemma Are You Getting Enough Calcium? You may be avoiding dairy products because of ... But dairy products are a major source of calcium, vitamin D and other nutrients that are important ...

  15. Principles of calcium-based biomineralization.

    PubMed

    Feng, Qingling

    2011-01-01

    The chapter provides some basic information on the formation principles of calcium carbonate in biological systems in marine environment in the point of view of materials science in order to provide strategies for biomimetic design and preparation of new functional materials. Many researchers try to explain the principles of biomineralization and get some valuable conclusions. This chapter introduces some calcium-based biominerals in aquatic organisms which mainly include calcium carbonate and calcium phosphate. Then it gives a presentation of the hierarchical structure of calcium carbonate-based and calcium phosphate-based biominerals, e.g., mollusc shell, pearl, carp otolith, tooth, and bone. Moreover, the chapter explains the principles of calcium carbonate mineralization from the aspects of the effects of additives and templates; it also gives some explanations to the principles of calcium phosphate mineralization.

  16. Calcium, vitamin D, and your bones

    MedlinePlus

    Green leafy vegetables, such as broccoli, collards, kale, mustard greens, turnip greens, and bok choy (Chinese cabbage), are good sources of calcium. Other good food sources of calcium are: Salmon and ...

  17. Magnesium/Calcium Competition at Excitable Membranes.

    ERIC Educational Resources Information Center

    Belzer, Bill; Fry, Panni

    1998-01-01

    Considers some consequences of altering intracellular calcium supply by magnesium concentration changes. Focuses on using this procedure as an exercise with allied health students as they witness therapeutic uses of magnesium and other calcium entry inhibitors. (DDR)

  18. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg... lime. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p....

  19. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg... lime. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p....

  20. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also... meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 52, which is incorporated...