Sample records for calcium 36

  1. Peptide YY (3-36) modulates intracellular calcium through activation of the phosphatidylinositol pathway in hippocampal neurons. (United States)

    Domingues, Michelle Flores; de Assis, Dênis Reis; Piovesan, Angela Regina; Belo, Cháriston André Dal; da Costa, Jaderson Costa


    Peptide YY (PYY) belongs to the neuropeptide Y (NPY) family, which also includes the pancreatic polypeptide (PP) and NPY. PYY is secreted by the intestinal L cells, being present in the blood stream in two active forms capable of crossing the blood brain barrier, PYY (1-36) and its cleavage product, PYY (3-36). PYY is a selective agonist for the Y2 receptor (Y2R) and these receptors are abundant in the hippocampus. Here we investigated the mechanisms by which PYY (3-36) regulates intracellular Ca 2+ concentrations ([Ca 2+ ] i ) in hippocampal neurons by employing a calcium imaging technique in hippocampal cultures. Alterations in [Ca 2+ ] i were detected by changes in the Fluo-4 AM reagent emission. PYY (3-36) significantly increased [Ca 2+ ] from the concentration of 10 -11 M as compared to the controls (infusion of HEPES-buffered solution (HBS) solution alone). The PYY (3-36)-increase in [Ca 2+ ] i remained unchanged even in Ca 2+ -free extracellular solutions. Sarcoplasmic/endoplasmic reticulum Ca 2+ -ATPase pump (SERCA pump) inhibition partially prevent the PYY (3-36)-increase of [Ca 2+ ] i and inositol 1,4,5-triphosphate receptor (IP3R) inhibition also decreased the PYY (3-36)-increase of [Ca 2+ ] i . Taken together, our data strongly suggest that PYY (3-36) mobilizes calcium from the neuronal endoplasmic reticulum (ER) stores towards the cytoplasm. Next, we showed that PYY (3-36) inhibited high K + -induced increases of [Ca 2+ ] i , suggesting that PYY (3-36) could also act by activating G-protein coupled inwardly rectifying potassium K + channels. Finally, the co-infusion of the Y2 receptor (Y2R) antagonist BIIE0246 with PYY (3-36) abolished the [Ca 2+ ] i increase induced by the peptide, suggesting that PYY (3-36)-induced [Ca 2+ ] i increase in hippocampal neurons occurs via Y2Rs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Calcium-dependent isolation of the 36-kilodalton substrate of pp60/sup src/-kinase. Fractionation of the phosphorylated and unphosphorylated species

    International Nuclear Information System (INIS)

    Soric, J.; Gordon, J.A.


    In this paper, the authors present a new and simple purification of the 36-kDa protein, a major substrate of both viral and growth factor-receptor associated tyrosine protein kinases, and its complex from normal and Schmidt-Ruppin strain Rous sarcoma virus-transformed chicken embryo fibroblasts that employs a DEAE-Sephacel column and introduces the calcium-dependent adsorption of 36-kDa protein. The use of EGTA step gradients differentially elutes the 36-kDa molecules from the DEAE-Sephacel column. An average total yield of the 36-kDa protein in all fractions approached 80% and represented 0.78% of the [ 35 S]methionine-labeled cellular protein. A purity of 95-99% was obtained with a yield of 60% in the central elution fractions from normal or Rous sarcoma virus-transformed chicken embryo fibroblasts. Furthermore, 2 mM EGTA elutes poorly phosphorylated molecules while heavily phosphorylated 36-kDa protein requires 4 or 6 M EGTA; a small residual fraction is released at 8-10 mM EGTA. If the EGTA step gradients were neutralized with Ca 2+ ion, elution of the 36-kDa protein is inhibited. Tyrosine phosphorylation of the 36-kDa protein is increased 2-3-fold following a short term incubation of whole cells with micromolar vanadate. The elution pattern (but not intensity) of the 36-kDa protein obtained from lysates of vanadate-treated cells was identical to untreated cell lysates. The additional phosphorylation appears to result from a recruitment of unphosphorylated 36-kDa protein as the position (but not intensity) of the phosphorylated tryptic peptides is unchanged. They conclude that the function of the 36-kDa protein may be calcium ion-dependent and may be influenced by the phosphorylation state of the protein

  3. Effect of calcium chloride and calcium lactate on quality and shelf-life of fresh-cut guava slices

    International Nuclear Information System (INIS)

    Raheem, M.I.U.; Huma, N.; Anjum, F.M.


    Present study was conducted to investigate the effectiveness of chemical treatments at low temperature on the quality of fresh-cut guava slices during 2011-12. Uniform sized guava slices were made free from seeds and treated with calcium chloride and calcium lactate with concentration 0.9%, 1.8%, 2.7% or 3.6%. After packing in plastic boxes, all treated samples were stored at 5 degree C + 2 degree C in a refrigerator for 24 days with 6 day interval between different removals. The results obtained from physico-chemical analysis showed decrease in firmness (111.67-12.67gf) and increase in browning (1.19-1.93nm) of guava slices compared to control with the passage of storage interval. Moreover, scores in taste (7.33-1.00), flavour (7.33-1.00), colour (7.50-1.00) and texture (7.67-1.00) of guava slices was also decreased with respect to interaction of treatments and storage period. Calcium chloride at the rate 2.7% showed significantly higher stability than other concentrations of calcium chloride and calcium lactate in delaying firmness and browning of fresh-cut guava slices along with maintaining their organoleptic properties for longer storage period. However, calcium chloride imparted undesirable bitterness to fresh-cut guava slices at the concentration of 3.6%. Based on the overall quality performance, 2.7% calcium chloride and 3.6% calcium lactate exhibited better results than other concentrations and control with storage life of 8 days at 5 degree C + 2 degree C. (author)

  4. Fatty acid translocase promoted hepatitis B virus replication by upregulating the levels of hepatic cytosolic calcium. (United States)

    Huang, Jian; Zhao, Lei; Yang, Ping; Chen, Zhen; Ruan, Xiong Z; Huang, Ailong; Tang, Ni; Chen, Yaxi


    Hepatitis B virus (HBV) is designated a "metabolovirus" due to the intimate connection between the virus and host metabolism. The nutrition state of the host plays a relevant role in the severity of HBV infection. Metabolic syndrome (MS) is prone to increasing HBV DNA loads and accelerating the progression of liver disease in patients with chronic hepatitis B (CHB). Cluster of differentiation 36 (CD36), also named fatty acid translocase, is known to facilitate long-chain fatty acid uptake and contribute to the development of MS. We recently found that CD36 overexpression enhanced HBV replication. In this study, we further explored the mechanism by which CD36 overexpression promotes HBV replication. Our data showed that CD36 overexpression increased HBV replication, and CD36 knockdown inhibited HBV replication. RNA sequencing found some of the differentially expressed genes were involved in calcium ion homeostasis. CD36 overexpression elevated the cytosolic calcium level, and CD36 knockdown decreased the cytosolic calcium level. Calcium chelator BAPTA-AM could override the HBV replication increased by CD36 overexpression, and the calcium activator thapsigargin could improve the HBV replication reduced by CD36 knockdown. We further found that CD36 overexpression activated Src kinase, which plays an important role in the regulation of the store-operated Ca 2+ channel. An inhibitor of Src kinase (SU6656) significantly reduced the CD36-induced HBV replication. We identified a novel link between CD36 and HBV replication, which is associated with cytosolic calcium and the Src kinase pathway. CD36 may represent a potential therapeutic target for the treatment of CHB patients with MS. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Oral calcium carbonate affects calcium but not phosphorus balance in stage 3–4 chronic kidney disease (United States)

    Hill, Kathleen M.; Martin, Berdine R.; Wastney, Meryl; McCabe, George P.; Moe, Sharon M.; Weaver, Connie M.; Peacock, Munro


    Chronic kidney disease (CKD) patients are given calcium carbonate to bind dietary phosphorus and reduce phosphorus retention, and to prevent negative calcium balance. Data are limited on calcium and phosphorus balance in CKD to support this. The aim of this study was to determine calcium and phosphorus balance and calcium kinetics with and without calcium carbonate in CKD patients. Eight stage 3/4 CKD patients, eGFR 36 mL/min, participated in two 3-week balances in a randomized placebo-controlled cross-over study of calcium carbonate (1500 mg/d calcium). Calcium and phosphorus balance were determined on a controlled diet. Oral and intravenous 45calcium with blood sampling and urine and fecal collections were used for calcium kinetics. Fasting blood and urine were collected at baseline and end of each week of each balance period for biochemical analyses. Results showed that patients were in neutral calcium and phosphorus balance while on placebo. Calcium carbonate produced positive calcium balance, did not affect phosphorus balance, and produced only a modest reduction in urine phosphorus excretion compared with placebo. Calcium kinetics demonstrated positive net bone balance but less than overall calcium balance suggesting tissue deposition. Fasting biochemistries of calcium and phosphate homeostasis were unaffected by calcium carbonate. If they can be extrapolated to effects of chronic therapy, these data caution against the use of calcium carbonate as a phosphate binder. PMID:23254903

  6. Antenatal calcium intake in Malaysia. (United States)

    Mahdy, Zaleha Abdullah; Basri, Hashimah; Md Isa, Zaleha; Ahmad, Shuhaila; Shamsuddin, Khadijah; Mohd Amin, Rahmah


    To determine the adequacy of antenatal calcium intake in Malaysia, and the influencing factors. A cross-sectional study was conducted among postnatal women who delivered in two tertiary hospitals. Data were collected from antenatal cards, hospital documents and diet recall on daily milk and calcium intake during pregnancy. SPSS version 19.0 was used for statistical analyses. A total of 150 women were studied. The total daily calcium intake was 834 ± 43 mg (mean ± standard error of the mean), but the calcium intake distribution curve was skewed to the right with a median intake of 725 mg daily. When calcium intake from milk and calcium supplements was excluded, the daily dietary calcium intake was only 478 ± 25 mg. Even with inclusion of milk and calcium supplements, more than a third (n=55 or 36.7%) of the women consumed less than 600 mg calcium in their daily diet. The adequacy of daily calcium intake was not influenced by maternal age, ethnicity, income or maternal job or educational status as well as parity. The daily dietary calcium intake of the Malaysian antenatal population is far from adequate without the addition of calcium supplements and milk. © 2013 The Authors. Journal of Obstetrics and Gynaecology Research © 2013 Japan Society of Obstetrics and Gynecology.

  7. In vitro calcium availability in bakery products fortified with tuna bone powder as a natural calcium source. (United States)

    Nemati, Mahnaz; Kamilah, Hanisah; Huda, Nurul; Ariffin, Fazilah


    Avoidance of dairy products due to lactose intolerance can lead to insufficiency of calcium (Ca) in the body. In an approach to address this problem, tuna bone powder (TBP) was formulated as a calcium supplement to fortify bakery products. In a study, TBP recovered by alkaline treatment contained 38.16 g/100 g of calcium and 23.31 g/100 g of phosphorus. The ratio of Ca:P that was close to 2:1 was hence comparable to that in human bones. The availability of calcium in TBP was 53.93%, which was significantly higher than most calcium salts, tricalcium phosphate (TCP) being the exception. In vitro availability of calcium in TBP-fortified cookies or TCP-fortified cookies were comparable at 38.9% and 39.5%, respectively. These values were higher than the readings from TBP-fortified bread (36.7%) or TCP-fortified bread (37.4%). Sensory evaluation of bakery products containing TBP or TCP elicited comparable scores for the two additives from test panels. Hence, TBP could be used in the production of high calcium bakery products that would enjoy consumer acceptance.

  8. Calcium levels and calcium: available phosphorus ratios in diets for white egg layers from 42 to 58 weeks of age

    Directory of Open Access Journals (Sweden)

    Silvana Marques Pastore


    Full Text Available The experiment was conducted to determine the nutritional requirement of calcium and the best calcium:available phosphorus ratio for commercial layers at the post-laying peak. A total of 324 Hy-Line W-36 laying hens were utilized in the period from 42 to 58 weeks of age, distributed in a completely randomized design in a 3 × 3 factorial arrangement, composed of three levels of calcium (39, 42 and 45 g/kg and three calcium:phosphorus ratios (12.12:1; 10.53:1; and 9.30:1, totaling nine treatments with six replications and six birds per experimental unit. There was no significant effect from the calcium levels × calcium:phosphorus ratio interaction for any of the variables studied. The calcium levels and the calcium:phosphorus ratios did not affect the variables performance or egg and bone quality. At the evaluation of the calcium:phosphorus balance, as the levels of calcium of the diet were raised, the intake of calcium and phosphorus and the contents of mineral matter and calcium in the excreta increased linearly, and the retention of calcium by birds decreased linearly. With the reduction of the calcium:phosphorus ratios of the diet, intake, retention and excretion of phosphorus by layers increased. Diets containing calcium at 39 g/kg and a calcium:phosphorus ratio of 12.12:1, corresponding to an increase in calcium of 3.51 g/bird/day and available phosphorus of 289 mg/bird/day, meet the requirements of calcium and available phosphorus of white egg layers in the period from 42 to 58 weeks of age.

  9. Direct transformation of calcium sulfite to {alpha}-calcium sulfate hemihydrate in a concentrated Ca-Mg-Mn chloride solution under atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Baohong Guan; Hailu Fu; Jie Yu; Guangming Jiang; Bao Kong; Zhongbiao Wu [Zhejiang University, Hangzhou (China). Department of Environmental Engineering


    Massive quantities of sulfite-rich flue gas desulfurization (FGD) scrubber sludge have been generated by coal burning power plants. Utilization of the sulfite-rich sludge for preparing {alpha}-calcium sulfate hemihydrate ({alpha}-HH), an important kind of cementitious material, is of particular interest to electric utilities and environmental preservation. In the experiment, calcium sulfite hemihydrate was directly transformed to {alpha}-HH without the occurrence of calcium sulfate dihydrate (DH). The transformation was performed in a concentrated CaCl{sub 2} solution containing Mg{sup 2+} and Mn{sup 2+} at 95{sup o}C, atmospheric pressure and low pH. The oxidation of calcium sulfite and the subsequent crystallization of {alpha}-HH constitute the whole conversion, during which the oxidation turns out to be the rate controlling step. Solid solution comprised of calcium sulfite hemihydrate and calcium sulfate was found to coexist with {alpha}-HH in the suspension. Calcium sulfate increases and calcium sulfite decreases spontaneously until the solid solution disappears. Thus, it is a potential alternative to utilize sulfite-rich FGD scrubber sludge for the direct preparation of {alpha}-HH. 36 refs., 10 figs., 1 tab.

  10. Calmodulin immunolocalization to cortical microtubules is calcium independent

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, D.D.; Cyr, R.J.


    Calcium affects the stability of cortical microtubules (MTs) in lysed protoplasts. This calmodulin (CaM)-mediated interaction may provide a mechanism that serves to integrate cellular behavior with MT function. To test the hypothesis that CaM associates with these MTs, monoclonal antibodies were produced against CaM, and one (designated mAb1D10), was selected for its suitability as an immunocytochemical reagent. It is shown that CaM associates with the cortical Mats of cultured carrot (Daucus carota L.) and tobacco (Nicotiana tobacum L.) cells. Inasmuch as CaM interacts with calcium and affects the behavior of these Mats, we hypothesized that calcium would alter this association. To test this, protoplasts containing taxol-stabilized Mats were lysed in the presence of various concentrations of calcium and examined for the association of Cam with cortical Mats. At 1 {mu}M calcium, many protoplasts did not have CaM in association with the cortical Mats, while at 3.6 {mu}M calcium, this association was completely abolished. The results are discussed in terms of a model in which CaM associates with Mats via two types of interactions; one calcium dependent and one independent.

  11. Calmodulin immunolocalization to cortical microtubules is calcium independent

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, D.D.; Cyr, R.J.


    Calcium affects the stability of cortical microtubules (MTs) in lysed protoplasts. This calmodulin (CaM)-mediated interaction may provide a mechanism that serves to integrate cellular behavior with MT function. To test the hypothesis that CaM associates with these MTs, monoclonal antibodies were produced against CaM, and one (designated mAb1D10), was selected for its suitability as an immunocytochemical reagent. It is shown that CaM associates with the cortical Mats of cultured carrot (Daucus carota L.) and tobacco (Nicotiana tobacum L.) cells. Inasmuch as CaM interacts with calcium and affects the behavior of these Mats, we hypothesized that calcium would alter this association. To test this, protoplasts containing taxol-stabilized Mats were lysed in the presence of various concentrations of calcium and examined for the association of Cam with cortical Mats. At 1 [mu]M calcium, many protoplasts did not have CaM in association with the cortical Mats, while at 3.6 [mu]M calcium, this association was completely abolished. The results are discussed in terms of a model in which CaM associates with Mats via two types of interactions; one calcium dependent and one independent.

  12. Calcium intake is not associated with increased coronary artery calcification: the Framingham Study. (United States)

    Samelson, Elizabeth J; Booth, Sarah L; Fox, Caroline S; Tucker, Katherine L; Wang, Thomas J; Hoffmann, Udo; Cupples, L Adrienne; O'Donnell, Christopher J; Kiel, Douglas P


    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, which is a measure of atherosclerosis that predicts risk of ischemic heart disease independent of other risk factors. This was an observational, prospective cohort study. Participants included 690 women and 588 men in the Framingham Offspring Study (mean age: 60 y; range: 36-83 y) who attended clinic visits and completed food-frequency questionnaires in 1998-2001 and underwent computed tomography scans 4 y later in 2002-2005. The mean age-adjusted coronary artery-calcification Agatston score decreased with increasing total calcium intake, and the trend was not significant after adjustment for age, BMI, smoking, alcohol consumption, vitamin D-supplement use, energy intake, and, for women, menopause status and estrogen use. Multivariable-adjusted mean Agatston scores were 2.36, 2.52, 2.16, and 2.39 (P-trend = 0.74) with an increasing quartile of total calcium intake in women and 4.32, 4.39, 4.19, and 4.37 (P-trend = 0.94) in men, respectively. Results were similar for dietary calcium and calcium supplement use. Our study does not support the hypothesis that high calcium intake increases coronary artery calcification, which is an important measure of atherosclerosis burden. The evidence is not sufficient to modify current recommendations for calcium intake to protect skeletal health with respect to vascular calcification risk.

  13. Inotropic effect, binding properties, and calcium flux effects of the calcium channel agonist CGP 28392 in intact cultured embryonic chick ventricular cells

    International Nuclear Information System (INIS)

    Laurent, S.; Kim, D.; Smith, T.W.; Marsh, J.D.


    CGP 28392 is a recently described dihydropyridine derivative with positive inotropic properties. To study the mechanism of action of this putative calcium channel agonist, we have related the effects of CGP 28392 on contraction (measured with an optical video system) and radioactive calcium uptake to ligand-binding studies in cultured, spontaneously beating chick embryo ventricular cells. CGP 28392 produced a concentration-dependent increase in amplitude and velocity of contraction (EC 50 = 2 x 10(-7) M; maximum contractile effect = 85% of the calcium 3.6 mM response). Nifedipine produced a shift to the right of the concentration-effect curve for CGP 28392 without decreasing the maximum contractile response, suggesting competitive antagonism (pA2 = 8.3). Computer analysis of displacement of [ 3 H]nitrendipine binding to intact heart cells by unlabeled CGP 28392 indicated a K /sub D/ = 2.2 +/- 0.95 x 10(-7) M, in good agreement with the EC 50 for the inotropic effect. CGP 28392 increased the rate of radioactive calcium influx (+39% at 10 seconds) without altering beating rate, while nifedipine decreased radioactive calcium influx and antagonized the CGP 28392-induced increase in calcium influx. Our results indicate that, in intact cultured myocytes, CGP 28392 acts as a calcium channel agonist and competes for the dihydropyridine-binding site of the slow calcium channel. In contrast to calcium channel blockers, CGP 28392 increases calcium influx and enhances the contractile state

  14. Dietary calcium deficiency in laying ducks impairs eggshell quality by suppressing shell biomineralization. (United States)

    Chen, Wei; Zhao, Fei; Tian, Zhi Mei; Zhang, Han Xing; Ruan, Dong; Li, Yan; Wang, Shuang; Zheng, Chun Tian; Lin, Ying Cai


    The objective of this study was to determine the effects of dietary calcium deficiency on the process of shell formation. Four hundred and fifty female ducks (Anas platyrhynchos) at 22 weeks were randomly assigned to three groups. Ducks were fed one of two calcium-deficient diets (containing 1.8% or 0.38% calcium, respectively) or a calcium-adequate control diet (containing 3.6% calcium) for 67 days (depletion period) and then all ducks were fed a calcium-adequate diet for an additional 67 days (repletion period). Compared with the calcium-adequate control, the average shell thickness, egg shell weight, breaking strength, mammillae density and mammillary knob thickness of shell from ducks that consumed the diet with 0.38% calcium were significantly decreased (Pducks fed 0.38% calcium but not 1.8% calcium. Plasma estradiol concentration was decreased by both of the calcium-deficient diets (Pstudy suggest that dietary calcium deficiency negatively affects eggshell quality and microarchitecture, probably by suppressing shell biomineralization. © 2015. Published by The Company of Biologists Ltd.

  15. Evaluation of blood zinc, calcium and blood lead levels among children aged 1-36 months. (United States)

    Ji, Xiaojun; He, Hong; Ren, Lisheng; Liu, Ji; Han, Chunhua


    Early childhood lead exposure is associated with numerous adverse health effects. Biomonitoring among susceptible populations, such as children, has not been previously conducted. The aim of the study is to evaluate the blood lead (Pb) and total blood calcium (Ca) levels; blood zinc (Zn) levels. A cross-sectional study was designed to collect healthy children age 1- 36 months (Mean ± SD: 1.5 ± 0.6 age, 60% boys) in the study from January 2010 to September 2011. The overall mean blood Pb levels were 42.18 ± 12.13 μg/L, the overall mean blood Zn and total blood Ca concentrations were 62.18 ± 12.33 μmol/L and 1.78 ± 0.13 mmol/L, respectively. The prevalence of elevated blood Pb levels in all children was 1.3%. A significant difference was found between female and male subjects for the blood Pb and Zn. After controlling for gender and age, there was a weak positive correlation between total blood Ca and Zn level. The blood Pb levels had a significant negative correlation with total blood Ca level after adjusting for age and gender, and these findings suggest that Pb had effect on positive blood Zn and total blood Ca levels; parents should pay more attention to the nutrition of girls. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  16. CD36 Protein Influences Myocardial Ca2+ Homeostasis and Phospholipid Metabolism CONDUCTION ANOMALIES IN CD36-DEFICIENT MICE DURING FASTING

    Czech Academy of Sciences Publication Activity Database

    Pietka, T. A.; Sulkin, M.S.; Kuda, Ondřej; Wang, W.; Zhou, D.; Yamada, K. A.; Yang, K.; Su, X.; Gross, R. W.; Nerbonne, J. M.; Efimov, I. R.; Abumrad, N. A.


    Roč. 287, č. 46 (2012), s. 38901-38912 ISSN 0021-9258 Institutional support: RVO:67985823 Keywords : calcium * cyclic AMP (cAMP) * heart * phospholipid * phospholipid metabolism * polyunsaturated fatty acids * CD36 deficiency * SERCA2a * sudden death Subject RIV: ED - Physiology Impact factor: 4.651, year: 2012

  17. Relation of thoracic aortic and aortic valve calcium to coronary artery calcium and risk assessment. (United States)

    Wong, Nathan D; Sciammarella, Maria; Arad, Yadon; Miranda-Peats, Romalisa; Polk, Donna; Hachamovich, Rory; Friedman, John; Hayes, Sean; Daniell, Anthony; Berman, Daniel S


    Aortic calcium, aortic valve calcium (AVC), and coronary artery calcium (CAC) have been associated with cardiovascular event risk. We examined the prevalence of thoracic aortic calcium (TAC) and AVC in relation to the presence and extent of CAC, cardiovascular risk factors, and estimated risk of coronary heart disease (CHD). In 2,740 persons without known CHD aged 20 to 79 years, CAC was assessed by electron beam- or multidetector-computed tomography. We determined the prevalence of TAC and AVC in relation to CAC, CHD risk factors, and predicted 10-year risk of CHD. A close correspondence of TAC and AVC was observed with CAC. TAC and AVC increased with age; by the eighth decade of life, the prevalence of TAC was similar to that of CAC (>80%), and 36% of men and 24% of women had AVC. Age, male gender, and low-density lipoprotein cholesterol were directly related to the likelihood of CAC, TAC, and AVC; higher diastolic blood pressure and cigarette smoking additionally predicted CAC. Body mass index and higher systolic and lower diastolic blood pressures were also related to TAC, and higher body mass index and lower diastolic blood pressure were related to AVC. Calculated risk of CHD increased with the presence of AVC and TAC across levels of CAC. TAC and AVC provided incremental value over CAC in association with the 10-year calculated risk of CHD. If longitudinal studies show an incremental value of aortic and aortic valve calcium over that of CAC for prediction of cardiovascular events, future guidelines for risk assessment incorporating CAC assessment may additionally incorporate the measurement of aortic and/or aortic valve calcium.

  18. Dietary calcium intake and risk of cardiovascular disease, stroke, and fracture in a population with low calcium intake. (United States)

    Kong, Sung Hye; Kim, Jung Hee; Hong, A Ram; Cho, Nam H; Shin, Chan Soo


    Background: The role of dietary calcium intake in cardiovascular disease (CVD), stroke, and fracture is controversial. Most previous reports have evaluated populations with high calcium intake. Objective: We aimed to evaluate whether high dietary calcium intake was associated with the risk of CVD, stroke, and fracture in a population with low calcium intake. Design: In a prospective cohort study beginning in 2001 in Ansung-Ansan, Korea, 2158 men and 2153 women aged >50 y were evaluated for all-cause mortality, CVD, stroke, and fractures over a median 9-y follow-up. Results: During follow-up, 242 and 100 deaths, 149 and 150 CVD events, 58 and 82 stroke events, and 211 and 292 incident fractures occurred in men and women, respectively. The first quartiles of energy-adjusted dietary calcium intake were 249 mg/d (IQR: 169 mg/d) in men and 209 mg/d (IQR: 161 mg/d) in women. Both men and women with higher dietary calcium intake tended to have higher fat, protein, sodium, phosphorus, fruit, and vegetable intakes. In men, outcomes were not significantly associated with dietary calcium intake with or without adjustments, and CVD risk tended to increase with increasing energy-adjusted dietary calcium intake, but this was not statistically significant ( P = 0.078 and P = 0.093 with and without adjustment, respectively). In women, CVD risk and dietary calcium intake showed a U-shaped association; the HRs (95% CIs) without adjustment relative to the first quartile were 0.71 (0.47, 1.07), 0.57 (0.36, 0.88), and 0.52 (0.33, 0.83) for quartiles 2, 3, and 4, respectively, and the values after adjustment were 0.70 (0.45, 1.07), 0.51 (0.31, 0.81), and 0.49 (0.29, 0.83) for quartiles 2, 3, and 4, respectively. Conclusion: In Korean women, increased dietary calcium intake was associated with a decreased CVD risk, but it did not influence the risk of stroke or fracture. © 2017 American Society for Nutrition.

  19. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Slade, A.M.; Nayler, W.G.; Meijler, F.L.


    Reperfusion of isolated hearts with calcium-containing solution after a short period of calcium-free perfusion results in irreversible cell damage (calcium paradox). This phenomenon is characterized by an excessive influx of calcium into the cells, the rapid onset of myocardial contracture,

  20. Effect of Casein Phosphopeptide-Amorphous Calcium Phosphate and Three Calcium Phosphate on Enamel Microhardness. (United States)

    Haghgou, En Hr; Haghgoo, Roza; Roholahi, Mohamad R; Ghorbani, Zahra


    This study aims to investigate the effect of casein phos-phopeptide-amorphous calcium phosphate and three calcium phosphate (CPP-ACP and TCP) on increasing the microhardness of human enamel after induction of erosion. A total of 26 healthy human-impacted third molar teeth were chosen, and their hardness measured using a microhardness testing machine. The samples were immersed in Coca Cola (pH = 4.7) for 8 minutes. Then, micro-hardness was measured again, and these samples were randomly divided into four groups (two control groups and two experimental groups). (1) Negative control group: Artificial saliva was used for 10 minutes, (2) positive control group: Fluoride gel was used for 10 minutes, (3) β-TCP group: TCP was used for 10 minutes, (4) CCP-ACP group: CCP-ACP was used for 10 minutes. The final microhardness of those samples was measured, and the changes in microhardness of teeth within group and between groups were analyzed using the paired and analysis of variance tests respectively. Results were considered statistically significant at a level of p < 0.05. No significant difference was observed in microhard-ness between CPP-ACP group and TCP group (p = 0.368) during the time microhardness significantly dropped after soaking in soda. Casein phosphopeptide-amorphous calcium phosphate and TCP increased the microhardness of teeth. The increase in hardness in the TCP group was higher than in the CPP-ACP group, but this difference was not significant (p = 0.36). Casein phosphopeptide-amorphous calcium phosphate and TCP can affect the remineralization of erosive lesions.

  1. A model of propagating calcium-induced calcium release mediated by calcium diffusion

    NARCIS (Netherlands)

    Backx, P. H.; de Tombe, P. P.; van Deen, J. H.; Mulder, B. J.; ter Keurs, H. E.


    The effect of sudden local fluctuations of the free sarcoplasmic [Ca++]i in cardiac cells on calcium release and calcium uptake by the sarcoplasmic reticulum (SR) was calculated with the aid of a simplified model of SR calcium handling. The model was used to evaluate whether propagation of calcium

  2. Arabidopsis calmodulin-like protein CML36 is a calcium (Ca2+) sensor that interacts with the plasma membrane Ca2+-ATPase isoform ACA8 and stimulates its activity. (United States)

    Astegno, Alessandra; Bonza, Maria Cristina; Vallone, Rosario; La Verde, Valentina; D'Onofrio, Mariapina; Luoni, Laura; Molesini, Barbara; Dominici, Paola


    Calmodulin-like (CML) proteins are major EF-hand-containing, calcium (Ca 2+ )-binding proteins with crucial roles in plant development and in coordinating plant stress tolerance. Given their abundance in plants, the properties of Ca 2+ sensors and identification of novel target proteins of CMLs deserve special attention. To this end, we recombinantly produced and biochemically characterized CML36 from Arabidopsis thaliana We analyzed Ca 2+ and Mg 2+ binding to the individual EF-hands, observed metal-induced conformational changes, and identified a physiologically relevant target. CML36 possesses two high-affinity Ca 2+ /Mg 2+ mixed binding sites and two low-affinity Ca 2+ -specific sites. Binding of Ca 2+ induced an increase in the α-helical content and a conformational change that lead to the exposure of hydrophobic regions responsible for target protein recognition. Cation binding, either Ca 2+ or Mg 2+ , stabilized the secondary and tertiary structures of CML36, guiding a large structural transition from a molten globule apo-state to a compact holoconformation. Importantly, through in vitro binding and activity assays, we showed that CML36 interacts directly with the regulative N terminus of the Arabidopsis plasma membrane Ca 2+ -ATPase isoform 8 (ACA8) and that this interaction stimulates ACA8 activity. Gene expression analysis revealed that CML36 and ACA8 are co-expressed mainly in inflorescences. Collectively, our results support a role for CML36 as a Ca 2+ sensor that binds to and modulates ACA8, uncovering a possible involvement of the CML protein family in the modulation of plant-autoinhibited Ca 2+ pumps. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Investigation of thermo luminesce properties of calcium chloride doped with manganese

    International Nuclear Information System (INIS)

    Farag, H.


    Thermoluminescence (TL) properties of calcium chloride doped with manganese (CaCI: Mn) have been investigated. Three thermoluminescence peaks were detected, where the prominent TL-peak appeared at 210 degree. TL response had a linear relation from 0.36 cGy up to 400cGy. The ratio between the sensitivity of calcium chloride: Mn and LiF-700 was found to be 1.42. The TL fading was studied by applying different annealing temperatures. The TL residual percentage was found to be 0.023% for 300degree annealing temperature after 50 min of annealing time. Fading was not observed for the sample, which was stored at room temperature. Calcium chloride doped with manganese could be used as personal radiation detector.

  4. Mammary-Specific Ablation of the Calcium-Sensing Receptor During Lactation Alters Maternal Calcium Metabolism, Milk Calcium Transport, and Neonatal Calcium Accrual (United States)

    Mamillapalli, Ramanaiah; VanHouten, Joshua; Dann, Pamela; Bikle, Daniel; Chang, Wenhan; Brown, Edward


    To meet the demands for milk calcium, the lactating mother adjusts systemic calcium and bone metabolism by increasing dietary calcium intake, increasing bone resorption, and reducing renal calcium excretion. As part of this adaptation, the lactating mammary gland secretes PTHrP into the maternal circulation to increase bone turnover and mobilize skeletal calcium stores. Previous data have suggested that, during lactation, the breast relies on the calcium-sensing receptor (CaSR) to coordinate PTHrP secretion and milk calcium transport with calcium availability. To test this idea genetically, we bred BLG-Cre mice with CaSR-floxed mice to ablate the CaSR specifically from mammary epithelial cells only at the onset of lactation (CaSR-cKO mice). Loss of the CaSR in the lactating mammary gland did not disrupt alveolar differentiation or milk production. However, it did increase the secretion of PTHrP into milk and decreased the transport of calcium from the circulation into milk. CaSR-cKO mice did not show accelerated bone resorption, but they did have a decrease in bone formation. Loss of the mammary gland CaSR resulted in hypercalcemia, decreased PTH secretion, and increased renal calcium excretion in lactating mothers. Finally, loss of the mammary gland CaSR resulted in decreased calcium accrual by suckling neonates, likely due to the combination of increased milk PTHrP and decreased milk calcium. These results demonstrate that the mammary gland CaSR coordinates maternal bone and calcium metabolism, calcium transport into milk, and neonatal calcium accrual during lactation. PMID:23782944

  5. Effect of curd washing on the properties of reduced-calcium and standard-calcium Cheddar cheese. (United States)

    Hou, Jia; McSweeney, Paul L H; Beresford, Thomas P; Guinee, Timothy P


    Washed (W) and nonwashed (NW) variants of standard (SCa) and reduced-calcium (RCa) Cheddar cheeses were made in triplicate, ripened for a 270-d period, and analyzed for composition and changes during maturation. Curd washing was applied to cheeses to give a target level of lactose plus lactic acid in cheese moisture of 3.9 g/100 g in the W cheese, compared with a value of 5.3 g/100 g of lactose plus lactic acid in cheese moisture in the control NW cheeses. The 4 cheese types were denoted standard calcium nonwashed (SCaNW), standard calcium washed (SCaW), reduced-calcium nonwashed (RCaNW), and reduced-calcium washed (RCaW). The mean calcium level was 760 mg/100 g in the SCaNW and SCaW and 660 mg/100 g in the RCaNW and RCaW cheeses. Otherwise the gross composition of all cheeses was similar, each with protein, fat, and moisture levels of ~26, 32, and 36 g/100 g, respectively. Curd washing significantly reduced the mean level of lactic acid in the SCaW cheese and residual lactose in both SCaW and RCaW cheeses. The mean pH of the standard-calcium cheese over the 270-d ripening period increased significantly with curd washing and ripening time, in contrast to the reduced-calcium cheese, which was not affected by the latter parameters. Otherwise curd washing had little effect on changes in populations of starter bacteria or nonstarter lactic acid bacteria, proteolysis, rheology, or color of the cheese during ripening. Descriptive sensory analysis at 270 d indicated that the SCaW cheese had a nuttier, sweeter, less fruity, and less rancid taste than the corresponding SCaNW cheese. In contrast, curd washing was not as effective in discriminating between the RCaW and RCaNW cheeses. The RCaW cheese had a more buttery, caramel odor and flavor, and a more bitter, less sweet, and nutty taste than the SCaW cheese, whereas the RCaNW had a more pungent and less fruity flavor, a less fruity odor, a saltier, more-bitter, and less acidic taste, and a more astringent mouthfeel than

  6. Calcium and Bone Turnover Markers in Acromegaly: A Prospective, Controlled Study. (United States)

    Constantin, Tina; Tangpricha, Vin; Shah, Reshma; Oyesiku, Nelson M; Ioachimescu, Octavian C; Ritchie, James; Ioachimescu, Adriana G


    Acromegaly has been associated with calcium-phosphate and bone turnover alterations. Controlled studies of these interactions are sparse. To evaluate calcium and bone metabolism in active and treated acromegaly. We conducted a controlled, prospective study at a tertiary referral center. We studied 22 patients with acromegaly referred for surgical or medical therapy (ACM) and 22 with nonfunctioning pituitary adenomas referred for surgery (control). Calcium (serum and urine), phosphorus, parathyroid hormone (PTH), 25-hydroxy- and 1,25-dihydroxy-vitamin D, bone turnover markers [serum C-terminal telopeptide of type 1 collagen (CTX) and procollagen type 1 N-terminal propeptide (P1NP)], and cytokines [receptor activator of nuclear factor κB ligand (RANK-L) and osteoprotegerin (OPG)] at baseline and 3 to 6 months after treatment. At baseline, the ACM group had lower PTH levels than controls (36.3 ± 13.9 pg/mL vs 56.0 ± 19.9 pg/mL) and higher phosphorus (4.34 ± 0.71 mg/dL vs 3.55 ± 0.50 mg/dL) (P acromegaly, serum calcium (9.52 ± 0.43 mg/dL to 9.26 ± 0.28 mg/dL), phosphorus (4.34 ± 0.71 mg/dL to 3.90 ± 0.80 mg/dL), and CTX (0.91 ± 0.75 ng/mL to 0.63 ± 0.68 ng/mL) decreased, while PTH increased (36.3 ± 13.9 pg/mL to 48.9 ± 16.7 pg/mL) (P Acromegaly patients exhibited PTH-independent calcium-phosphate alterations and enhanced coupled bone formation and resorption. Within 6 months of treatment, bone resorption decreased, whereas RANK-L/OPG changes were inconsistent. Copyright © 2017 Endocrine Society

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

    NARCIS (Netherlands)

    Jonge, H.J. de; Gans, R.O.; Huls, G.A.


    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

  8. Interplay of Plasma Membrane and Vacuolar Ion Channels, Together with BAK1, Elicits Rapid Cytosolic Calcium Elevations in Arabidopsis during Aphid Feeding[OPEN (United States)

    Vincent, Thomas R.; Avramova, Marieta; Canham, James; Higgins, Peter; Bilkey, Natasha; Mugford, Sam T.; Pitino, Marco; Toyota, Masatsugu


    A transient rise in cytosolic calcium ion concentration is one of the main signals used by plants in perception of their environment. The role of calcium in the detection of abiotic stress is well documented; however, its role during biotic interactions remains unclear. Here, we use a fluorescent calcium biosensor (GCaMP3) in combination with the green peach aphid (Myzus persicae) as a tool to study Arabidopsis thaliana calcium dynamics in vivo and in real time during a live biotic interaction. We demonstrate rapid and highly localized plant calcium elevations around the feeding sites of M. persicae, and by monitoring aphid feeding behavior electrophysiologically, we demonstrate that these elevations correlate with aphid probing of epidermal and mesophyll cells. Furthermore, we dissect the molecular mechanisms involved, showing that interplay between the plant defense coreceptor BRASSINOSTEROID INSENSITIVE-ASSOCIATED KINASE1 (BAK1), the plasma membrane ion channels GLUTAMATE RECEPTOR-LIKE 3.3 and 3.6 (GLR3.3 and GLR3.6), and the vacuolar ion channel TWO-PORE CHANNEL1 (TPC1) mediate these calcium elevations. Consequently, we identify a link between plant perception of biotic threats by BAK1, cellular calcium entry mediated by GLRs, and intracellular calcium release by TPC1 during a biologically relevant interaction. PMID:28559475

  9. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium pantothenate, calcium chloride double salt... FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may...

  10. Determination of percent calcium carbonate in calcium chromate

    International Nuclear Information System (INIS)

    Middleton, H.W.


    The precision, accuracy and reliability of the macro-combustion method is superior to the Knorr alkalimetric method, and it is faster. It also significantly reduces the calcium chromate waste accrual problem. The macro-combustion method has been adopted as the official method for determination of percent calcium carbonate in thermal battery grade anhydrous calcium chromate and percent calcium carbonate in quicklime used in the production of calcium chromate. The apparatus and procedure can be used to measure the percent carbonate in inorganic materials other than calcium chromate. With simple modifications in the basic apparatus and procedure, the percent carbon and hydrogen can be measured in many organic material, including polymers and polymeric formulations. 5 figures, 5 tables

  11. Characteristics of Solid-State Calcium Ion Sensors Based on Photocurable and Selfplasticising Polyacrylate Matrices

    Directory of Open Access Journals (Sweden)

    Lee Yook Heng


    Full Text Available New membrane materials based on cross-linked poly(n-butyl acrylate (nBA, have been used successfully as calcium ion-selective membranes. These membrane materials possess selfplasticising property and hence do not require plasticisers. The photocurability and good adhesion characteristics of these polymer matrices enable workable solid-state calcium ion sensors to be fabricated by simple photocure procedures employing the calcium ionophore ETH5234 and a lipophilic additive as ion sensing components. The calcium ion-selectivity of the sensors can be controlled by varying the chemical composition of the photocured  membrane. An optimum amount of the cross-linker 2,2-hexanedioldiacrylate (HDDA and the incorporation of n-heptyl acrylate (nHA led to improvement in the calcium ion-selectivity. The best calcium ion-selectivity was obtained from a copolymer membrane with composition: nBA = 74 wt-%, nHA = 20 wt-% and HDDA = 0.1 wt-%. The selectivity coefficients of calcium over major cations were: LogKCaPot,Na= -4.4,  LogKCaPot,K = -3.6, LogKCa,PotLi = -5.9, LogKCaPot,Mg= -4.4 with a Nernstian slope (29.1 ± 0.8 mV/decade under buffered conditions. This potentiometric performance is comparable to other solid-state calcium ion sensors with various plasticised polymer membranes.

  12. Evolution of the Calcium Paradigm: The Relation between Vitamin D, Serum Calcium and Calcium Absorption

    Directory of Open Access Journals (Sweden)

    Borje E. Christopher Nordin


    Full Text Available Osteoporosis is the index disease for calcium deficiency, just as rickets/osteomalacia is the index disease for vitamin D deficiency, but there is considerable overlap between them. The common explanation for this overlap is that hypovitaminosis D causes malabsorption of calcium which then causes secondary hyperparathyroidism and is effectively the same thing as calcium deficiency. This paradigm is incorrect. Hypovitaminosis D causes secondary hyperparathyroidism at serum calcidiol levels lower than 60 nmol/L long before it causes malabsorption of calcium because serum calcitriol (which controls calcium absorption is maintained until serum calcidiol falls below 20 nmol/L. This secondary hyperparathyroidism, probably due to loss of a “calcaemic” action of vitamin D on bone first described in 1957, destroys bone and explains why vitamin D insufficiency is a risk factor for osteoporosis. Vitamin D thus plays a central role in the maintenance of the serum (ionised calcium, which is more important to the organism than the preservation of the skeleton. Bone is sacrificed when absorbed dietary calcium does not match excretion through the skin, kidneys and bowel which is why calcium deficiency causes osteoporosis in experimental animals and, by implication, in humans.

  13. Calcium absorption

    International Nuclear Information System (INIS)

    Carlmark, B.; Reizenstein, P.; Dudley, R.A.


    The methods most commonly used to measure the absorption and retention of orally administered calcium are reviewed. Nearly all make use of calcium radioisotopes. The magnitude of calcium absorption and retention depends upon the chemical form and amount of calcium administered, and the clinical and nutritional status of the subject; these influences are briefly surveyed. (author)

  14. Radioisotope 45Ca labeling four calcium chemical compounds and tracing calcium bioavailability

    International Nuclear Information System (INIS)

    Zheng Hui; Zhen Rong; Niu Huisheng; Li Huaifen


    Objective: To build up a new method of the radioisotope 45 Ca labeling four calcium chemical compounds, observe and tracing bioavailability change of calcium labeled with radioisotope 45 Ca. Methods: The calcium gluconate (Ca-Glu), calcium citrate (Ca-Cit), calcium carbonate (Ca-Car) and calcium L-threonate (Ca-Thr)were labeled by radioisotope 45 Ca. Four calcium chemical compounds of 45 Ca labeling were used of calcium content 200 mg/kg in the rats and measure the absorption content and bioavailability of calcium in tissue of heart, lever spleen, stomach, kidney, brain, intestine, whole blood, urine, faeces. Results: 1) Radioisotope 45 Ca labeling calcium chemical compound has high radio intensity, more steady standard curve and recover rate. 2) The absorption of organic calcium chemical compounds is higher than the inorganic calcium chemical compound in the study of calcium bioavailability. Conclusion: The method of tracing with radioisotope 45 Ca labeling calcium chemical compounds has the characteristic of the sensitive, objective, accurate and steady in the study of calcium bioavailability

  15. The impact of calcium assay change on a local adjusted calcium equation. (United States)

    Davies, Sarah L; Hill, Charlotte; Bailey, Lisa M; Davison, Andrew S; Milan, Anna M


    Deriving and validating local adjusted calcium equations is important for ensuring appropriate calcium status classification. We investigated the impact on our local adjusted calcium equation of a change in calcium method by the manufacturer from cresolphthalein complexone to NM-BAPTA. Calcium and albumin results from general practice requests were extracted from the Laboratory Information Management system for a three-month period. Results for which there was evidence of disturbance in calcium homeostasis were excluded leaving 13,482 sets of results for analysis. The adjusted calcium equation was derived following least squares regression analysis of total calcium on albumin and normalized to the mean calcium concentration of the data-set. The revised equation (NM-BAPTA calcium method) was compared with the previous equation (cresolphthalein complexone calcium method). The switch in calcium assay resulted in a small change in the adjusted calcium equation but was not considered to be clinically significant. The calcium reference interval differed from that proposed by Pathology Harmony in the UK. Local adjusted calcium equations should be re-assessed following changes in the calcium method. A locally derived reference interval may differ from the consensus harmonized reference interval. © The Author(s) 2015.

  16. Calcium Lactate addition in Bioconcrete: Effect on Compressive strength and Water penetration

    Directory of Open Access Journals (Sweden)

    Irwan J.M


    Full Text Available This paper presents compressive strength and water penetration of bioconcrete with addition of calcium lactate. Bioconcrete has higher engineering concrete properties and durability compared to normal concrete but the natural production of calcium carbonate is limited to the calcium content in cement. Therefore, additional calcium is added as an additional calcium source to study the influence towards compressive strength and water penetration. The bacteria used in this research are Enterococcus faecalis and Bacillus sp. Calcium lactate was added into concrete mix in concentrations of 0.001mol/l, 0.005mol/l and 0.01mol/l of liquid used. The concentration of bacteria added into the mix is by partial replacement of water used in casting, which are 3% for Enterococcus faecalis and 5% for Bacillus sp. Both compressive strength and water penetration test used cubes of 150mm × 150mm × 150mm. The cubes were tested after 28 days. The result of compressive strength for control is 36 MPa while partial replacement of bacteria yields 38.2 MPa for 3% Enterococcus faecalis and 37.0 MPa for 5% Bacillus sp. Calcium lactate with 0.005 mol/L has the best performance with 42.8 MPa for Enterococcus faecalis and 39.6 MPa for Bacillus sp. Whereas for water penetration, the best concentration of calcium lactate which yielded the lowest water penetration is 0.01 mol/l for both Enterococcus faecalis and Bacillus sp which are 8.7 cm and 8 cm respectively. The addition of calcium lactate into bioconcrete is quite promising for improvement of concrete properties and durability.

  17. Calcium supplements (United States)

    ... this page: // Calcium supplements To use the sharing features on this page, please enable JavaScript. WHO SHOULD TAKE CALCIUM SUPPLEMENTS? Calcium is an important mineral for the ...

  18. Calcium waves. (United States)

    Jaffe, Lionel F


    Waves through living systems are best characterized by their speeds at 20 degrees C. These speeds vary from those of calcium action potentials to those of ultraslow ones which move at 1-10 and/or 10-20 nm s(-1). All such waves are known or inferred to be calcium waves. The two classes of calcium waves which include ones with important morphogenetic effects are slow waves that move at 0.2-2 microm s(-1) and ultraslow ones. Both may be propagated by cycles in which the entry of calcium through the plasma membrane induces subsurface contraction. This contraction opens nearby stretch-sensitive calcium channels. Calcium entry through these channels propagates the calcium wave. Many slow waves are seen as waves of indentation. Some are considered to act via cellular peristalsis; for example, those which seem to drive the germ plasm to the vegetal pole of the Xenopus egg. Other good examples of morphogenetic slow waves are ones through fertilizing maize eggs, through developing barnacle eggs and through axolotl embryos during neural induction. Good examples of ultraslow morphogenetic waves are ones during inversion in developing Volvox embryos and across developing Drosophila eye discs. Morphogenetic waves may be best pursued by imaging their calcium with aequorins.

  19. Absorbability of calcium from calcium-bound phosphoryl oligosaccharides in comparison with that from various calcium compounds in the rat ligated jejunum loop. (United States)

    To-o, Kenji; Kamasaka, Hiroshi; Nishimura, Takahisa; Kuriki, Takashi; Saeki, Shigeru; Nakabou, Yukihiro


    Calcium-bound phosphoryl oligosaccharides (POs-Ca) were prepared from potato starch. Their solubility and in situ absorbability as a calcium source were investigated by comparing with the soluble calcium compounds, calcium chloride and calcium lactate, or insoluble calcium compounds, calcium carbonate and dibasic calcium phosphate. The solubility of POs-Ca was as high as that of calcium chloride and about 3-fold higher than that of calcium lactate. An in situ experiment showed that the intestinal calcium absorption rate of POs-Ca was almost comparable with that of the soluble calcium compounds, and was significantly higher (pcalcium groups. Moreover, the total absorption rate of a 1:1 mixture of the calcium from POs-Ca and a whey mineral complex (WMC) was significantly higher (psoluble calcium source with relatively high absorption in the intestinal tract.

  20. Get Enough Calcium (United States)

    ... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... women, don't get enough calcium. How much calcium do I need every day? Women: If you ...

  1. The Effects of Dietary Calcium and/or Iron Deficiency upon Murine Intestinal Calcium Binding Protein Activity and Calcium Absorption


    McDonald, Catherine M.


    Iron deficiency has been shown to impair calcium absorption, leading to decreased bone mass. Vitamin D3-dependent calcium binding protein (CaBP) has been demonstrated to be necessary for the active transport of calcium in the intestine of numerous species. Iron deficiency might affect the activity of the calcium binding protein. Four experimental diets were formulated as follows: Diet 1, iron adequate, calcium adequate; Diet 2, iron deficient, calcium adequate; Diet 3, iron adequate, calci...

  2. Effects of diphosphonate on kidney calcium content and duodenal absorption of 45calcium

    International Nuclear Information System (INIS)

    Goulding, A.; Cameron, V.


    In rats the relationships between EHDP-induced changes in serum calcium concentration, kidney calcium content and duodenal transport of 45 calcium were studied. Body weights and kidney weights were similar in all groups. EHDP administration was associated with an increase in serum calcium concentration and kidney calcium content, and a decrease in duodenal 45 calcium transport. In the EHDP-treated rats, there was a significant negative correlation between kidney calcium concentration and duodenal 45 calcium transport but no correlation between either kidney calcium content and serum calcium concentration (r = 0.116) or between serum calcium concentration and duodenal 45 calcium transport (r = 0.02). Further experiments will be needed to determine whether the demonstrated increase in kidney calcium content induced by EHDP administration was the cause of, or was secondary to, inhibition of 1, 25(OH) 2 D 3 synthesis. (orig./AJ) [de

  3. Effect of lowering dietary calcium intake on fractional whole body calcium retention

    International Nuclear Information System (INIS)

    Dawson-Hughes, B.; Stern, D.T.; Shipp, C.C.; Rasmussen, H.M.


    Although fractional calcium absorption is known to vary inversely with calcium intake, the extent and timing of individual hormonal and calcium absorption responses to altered calcium intake have not been defined. We measured fractional whole body retention of orally ingested 47 Ca, an index of calcium absorption, in nine normal women after they had eaten a 2000-mg calcium diet for 8 weeks and a 300-mg calcium diet for 1, 2, 4, and 8 weeks. After the diet change, serum intact PTH (32.2% increase; P = 0.005), serum 1,25-dihydroxyvitamin D [1,25-(OH)2D; 43.8% increase; P = 0.003], and fractional whole body calcium retention (42.8% increase; P = 0.004) increased within 1 week. Although the PTH and calcium retention responses remained fairly constant throughout the low calcium intake period, serum 1,25-(OH)2D concentrations declined toward baseline after week 1. Thus, the late increase in calcium retention may have resulted from calcium absorption that was independent of 1,25-(OH)2D stimulation

  4. Calcium signals can freely cross the nuclear envelope in hippocampal neurons: somatic calcium increases generate nuclear calcium transients

    Directory of Open Access Journals (Sweden)

    Bading Hilmar


    Full Text Available Abstract Background In hippocampal neurons, nuclear calcium signaling is important for learning- and neuronal survival-associated gene expression. However, it is unknown whether calcium signals generated by neuronal activity at the cell membrane and propagated to the soma can unrestrictedly cross the nuclear envelope to invade the nucleus. The nuclear envelope, which allows ion transit via the nuclear pore complex, may represent a barrier for calcium and has been suggested to insulate the nucleus from activity-induced cytoplasmic calcium transients in some cell types. Results Using laser-assisted uncaging of caged calcium compounds in defined sub-cellular domains, we show here that the nuclear compartment border does not represent a barrier for calcium signals in hippocampal neurons. Although passive diffusion of molecules between the cytosol and the nucleoplasm may be modulated through changes in conformational state of the nuclear pore complex, we found no evidence for a gating mechanism for calcium movement across the nuclear border. Conclusion Thus, the nuclear envelope does not spatially restrict calcium transients to the somatic cytosol but allows calcium signals to freely enter the cell nucleus to trigger genomic events.

  5. Calcium hydroxide isotope effect in calcium isotope enrichment by ion exchange

    International Nuclear Information System (INIS)

    Jepson, B.E.; Shockey, G.C.


    The enrichment of calcium isotopes has been observed in ion-exchange chromatography with an aqueous phase of calcium hydroxide and a solid phase of sulfonic acid resin. The band front was exceedingly sharp as a result of the acid-base reaction occuring at the front of the band. Single-stage separation coefficients were found to be epsilon( 44 Ca/ 40 Ca) = 11 x 10 -4 and epsilon( 48 Ca/ 40 Ca) = 18 x 10 -4 . The maximum column separation factors achieved were 1.05 for calcium-44 and 1.09 for calcium-48 with the heavy isotopes enriching in the fluid phase. The calcium isotope effect between fully hydrated aqueous calcium ions and undissociated aqueous calcium hydroxide was estimated. For the calcium-44/40 isotope pair the separation coefficient was 13 x 10 -4 . 20 references, 2 figures

  6. Calcium (United States)

    ... You can get decent amounts of calcium from baked beans, navy beans, white beans, and others. Canned fish. You're in luck if you like sardines and canned salmon with bones. Almond milk. Working Calcium Into Your ...

  7. Influence of dietary calcium on bone calcium utilization

    International Nuclear Information System (INIS)

    Farmer, M.; Roland, D.A. Sr.; Clark, A.J.


    In Experiment 1, 10 microCi 45 Ca/day were administered to 125 hens for 10 days. Hens were then allocated to five treatments with calcium levels ranging from .08 to 3.75% of the diet. In Experiment 2, hens with morning oviposition times were randomly allocated to 11 treatments that were periods of time postoviposition ranging from 6 hr to 24 hr, in 2-hr increments (Experiment 2). At the end of each 2-hr period, eggs from 25 hens were removed from the uterus. The 18-, 20-, and 22-hr treatments were replicated three times. In Experiment 3, hens were fed either ad libitum or feed was withheld the last 5 or 6 hr before oviposition. In Experiment 4, hens were fed 10 microCi of 45 Ca for 15 days to label skeletal calcium. Hens were divided into two groups and fed a .08 or 3.75% calcium diet for 2 days. On the second day, 25 hens fed the 3.75% calcium diet were intubated with 7 g of the same diet containing .5 g calcium at 1700, 2100, 0100, 0500, and 0700 hr. The measurements used were egg weight, shell weight, and 45 Ca content of the egg shell. Results indicated a significant linear or quadratic regression of dietary calcium levels on 45 Ca accumulation in eggshells and eggshell weight (Experiment 1). As the calcium level of the diet increased, eggshell weight increased and 45 Ca recovery decreased. Utilization of skeletal calcium for shell formation ranged from 28 to 96%. In Experiment 2, the rate of shell calcification was not constant throughout the calcification process but varied significantly

  8. Calcium D-saccharate

    DEFF Research Database (Denmark)

    Garcia, André Castilho; Hedegaard, Martina Vavrusova; Skibsted, Leif Horsfelt


    Molar conductivity of saturated aqueous solutions of calcium d-saccharate, used as a stabilizer of beverages fortified with calcium d-gluconate, increases strongly upon dilution, indicating complex formation between calcium and d-saccharate ions, for which, at 25 °C, Kassoc = 1032 ± 80, ΔHassoc......° = -34 ± 6 kJ mol-1, and ΔSassoc° = -55 ± 9 J mol-1 K-1, were determined electrochemically. Calcium d-saccharate is sparingly soluble, with a solubility product, Ksp, of (6.17 ± 0.32) × 10-7 at 25 °C, only moderately increasing with the temperature: ΔHsol° = 48 ± 2 kJ mol-1, and ΔSassoc° = 42 ± 7 J mol-1...... K-1. Equilibria in supersaturated solutions of calcium d-saccharate seem only to adjust slowly, as seen from calcium activity measurements in calcium d-saccharate solutions made supersaturated by cooling. Solutions formed by isothermal dissolution of calcium d-gluconate in aqueous potassium d...

  9. Brief communication: ikaite (CaCO3*6H2O) discovered in Arctic sea ice (United States)

    Dieckmann, G. S.; Nehrke, G.; Uhlig, C.; Göttlicher, J.; Gerland, S.; Granskog, M. A.; Thomas, D. N.


    We report for the first time on the discovery of calcium carbonate crystals as ikaite (CaCO3*6H2O) in sea ice from the Arctic (Kongsfjorden, Svalbard). This finding demonstrates that the precipitation of calcium carbonate during the freezing of sea ice is not restricted to the Antarctic, where it was observed for the first time in 2008. This finding is an important step in the quest to quantify its impact on the sea ice driven carbon cycle and should in the future enable improvement parametrization sea ice carbon models.

  10. Estimation of presynaptic calcium currents and endogenous calcium buffers at the frog neuromuscular junction with two different calcium fluorescent dyes. (United States)

    Samigullin, Dmitry; Fatikhov, Nijaz; Khaziev, Eduard; Skorinkin, Andrey; Nikolsky, Eugeny; Bukharaeva, Ellya


    At the frog neuromuscular junction, under physiological conditions, the direct measurement of calcium currents and of the concentration of intracellular calcium buffers-which determine the kinetics of calcium concentration and neurotransmitter release from the nerve terminal-has hitherto been technically impossible. With the aim of quantifying both Ca(2+) currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dye Magnesium Green or the high-affinity dye Oregon Green BAPTA-1, simultaneously with microelectrode recordings of nerve-action potentials and end-plate currents. The action-potential-induced fluorescence signals in the nerve terminals developed much more slowly than the postsynaptic response. To clarify the reasons for this observation and to define a spatiotemporal profile of intracellular calcium and of the concentration of mobile and fixed calcium buffers, mathematical modeling was employed. The best approximations of the experimental calcium transients for both calcium dyes were obtained when the calcium current had an amplitude of 1.6 ± 0.08 pA and a half-decay time of 1.2 ± 0.06 ms, and when the concentrations of mobile and fixed calcium buffers were 250 ± 13 μM and 8 ± 0.4 mM, respectively. High concentrations of endogenous buffers define the time course of calcium transients after an action potential in the axoplasm, and may modify synaptic plasticity.

  11. Research of calcium oxide hydration in calcium nitrate solutions

    Directory of Open Access Journals (Sweden)

    M.A. Oliynyk


    Full Text Available Mineral fertilizers are one of the important factors of agriculture intensification and increasing of food products quantity. The volume of fertilizers production and its domestic consumption in Ukraine indicate that nitrogen fertilizer using only comes nearer to the required number of science-based. One of the most widespread artificial fertilizers is the calcium nitrate. Aim: The aim is to study and theoretically substantiate the processes occurring in the preparation of suspensions of calcium hydroxide Са(ОН2 in solution of calcium nitrate Ca(NО32. Materials and Methods: The technical calcium oxide (quicklime DSTU BV.2.7-90-99, solutions of calcium nitrate of 15, 20, 25, 30, 35 and 40% Ca(NО32 concentrations were used in the work. The content of lime in the preparation of a suspension in the solution changed (in terms of calcium oxide CaO from 150 g/dm3 to the maximum possible. Each of these solutions saturated at 40°С in lime to maximum concentration. Suitable for use in these experiments and in the technology of calcium nitrate obtaining are considered the solutions (suspensions that within 12 hours did not lose their mobility (transportability. Results: The experimental results show that increasing of the concentration of calcium nitrate in solution within the range 15...40%, the amount of lime that you can put into the solution without loss of transportability decreases. Further increasing of lime quantity in solutions concentrations causes to its solidifying, loss of mobility (transportability. Calculations showed that in the presence of calcium nitrate the solubility of Са(ОН2 is reduced nearly by order that can lead to the formation of calcium oxide CaO the solid phase Са(ОН2 on the surface, which also can form hydrogen bonds with the components of the solution. As the probability of formation of hydrogen bonds in solutions is high, there is a possibility of formation of clusters.

  12. Production of precipitated calcium carbonate from calcium silicates and carbon dioxide

    International Nuclear Information System (INIS)

    Teir, Sebastian; Eloneva, Sanni; Zevenhoven, Ron


    The possibilities for reducing carbon dioxide emissions from the pulp and paper industry by calcium carbonation are presented. The current precipitated calcium carbonate (PCC) production uses mined, crushed calcium carbonate as raw materials. If calcium silicates were used instead, carbon dioxide emissions from the calcination of carbonates would be eliminated. In Finland, there could, thus, be a potential for eliminating 200 kt of carbon dioxide emissions per year, considering only the PCC used in the pulp and paper industry. A preliminary investigation of the feasibility to produce PCC from calcium silicates and the potential to replace calcium carbonate as the raw material was made. Calcium carbonate can be manufactured from calcium silicates by various methods, but only a few have been experimentally verified. The possibility and feasibility of these methods as a replacement for the current PCC production process was studied by thermodynamic equilibrium calculations using HSC software and process modelling using Aspen Plus[reg]. The results from the process modelling showed that a process that uses acetic acid for extraction of the calcium ions is a high potential option for sequestering carbon dioxide by mineral carbonation. The main obstacle seems to be the limited availability and relatively high price of wollastonite, which is a mineral with high calcium silicate content. An alternative is to use the more common, but also more complex, basalt rock instead

  13. Estimation of presynaptic calcium currents and endogenous calcium buffers at the frog neuromuscular junction with two different calcium fluorescent dyes

    Directory of Open Access Journals (Sweden)

    Dmitry eSamigullin


    Full Text Available At the frog neuromuscular junction, under physiological conditions, the direct measurement of calcium currents and of the concentration of intracellular calcium buffers—which determine the kinetics of calcium concentration and neurotransmitter release from the nerve terminal—has hitherto been technically impossible. With the aim of quantifying both Ca2+ currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dye Magnesium Green or the high-affinity dye Oregon Green BAPTA-1, simultaneously with microelectrode recordings of nerve-action potentials and end-plate currents. The action-potential-induced fluorescence signals in the nerve terminals developed much more slowly than the postsynaptic response. To clarify the reasons for this observation and to define a spatiotemporal profile of intracellular calcium and of the concentration of mobile and fixed calcium buffers, mathematical modeling was employed. The best approximations of the experimental calcium transients for both calcium dyes were obtained when the calcium current had an amplitude of 1.6 ± 0.08 рА and a half-decay time of 1.2 ± 0.06 ms, and when the concentrations of mobile and fixed calcium buffers were 250 ± 13 µM and 8 ± 0.4 mM, respectively. High concentrations of endogenous buffers define the time course of calcium transients after an action potential in the axoplasm, and may modify synaptic plasticity.

  14. Calcium electroporation in three cell lines; a comparison of bleomycin and calcium, calcium compounds, and pulsing conditions

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gissel, Hanne; Hojman, Pernille


    offers several advantages over standard treatment options: calcium is inexpensive and may readily be applied without special precautions, as is the case with cytostatic drugs. Therefore, details on the use of calcium electroporation are essential for carrying out clinical trials comparing calcium...

  15. Transcellular transport of calcium

    Energy Technology Data Exchange (ETDEWEB)

    Terepka, A R; Coleman, J R; Armbrecht, H J; Gunter, T E


    Studies of two calcium transporting epithelia, embryonic chick chorioallantoic membrane and the small intestine of rat and chick, have strongly suggested that the transfer of calcium across a cell involves processes distinctly different from intracellular calcium ion regulation. In the proposed model, transcellular calcium transport is considered as a specialized process developed only by certain cells in those tissues charged with bulk transfer of calcium. The overall effect of the endocytotic mechanism is bulk calcium movement across a cell, protection of mitochondria from exposure to high concentrations of calcium, and the avoidance of wide and potentially toxic fluctuations in cytosol ionic calcium levels. (MFB)


    Directory of Open Access Journals (Sweden)

    Elka N. Radeva


    Full Text Available Introduction: Calcium hydroxide is widely used in the field of endodontics as a temporary root canal filling. This medicament significantly increases pH and optimizes the treatment outcome. Its total removal before final obturation is very important. Otherwise it could affect the hermetic filling and respectively the endodontic success. Aim: To evaluate the most effective irrigation protocol of calcium hydroxide removal from root canals. Materials and methods: In this study 36 single root canal teeth were observed. They were randomly divided into three groups (n=10 each group according to the technique applied for calcium hydroxide removal - manual irrigation, irrigation and Revo-S rotary instrumentation; and passive ultrasonic irrigation, and a control group (n=6 – irrigation with distilled water only. After calcium hydroxide removals following the procedures above, teeth were separated longitudinally in a buccal-lingual direction and remnants of medicaments were observed in the apical, middle and coronal part of each tooth. Then all of the specimens were observed using scanning electron microscopy and evaluated by a specified scale. The results have undergone statistical analysis. Results: In the case of calcium hydroxide in the apex and in the middle with highest average is Revo-S, followed by Ultrasonic and irrigation. In the coronal part the highest average belongs to Revo-S, irrigation and Ultrasonic. In all groups the highest average is represented by control group. Conclusion: There is not a universal technique for removal of intracanal medicaments and applying more than one protocol is required.

  17. Trace element studies in urolithiasis; preliminary investigation on mixed calcium oxalate-struvite urinary calculi

    International Nuclear Information System (INIS)

    Syed, A.M.; Qadiruddin, M.; Shirin, K.; Manser, W.W.T.


    In this study the levels of the trace elements copper , zinc, lead, iron, aluminum, nickel, chromium along with magnesium, sodium and potassium were estimated in fifteen mixed calcium oxalate-struvite (CaOx/STR) urinary stones. The mean values of the combined results were, copper 4.24, zinc 1302, zinc 1302.10, lead 23.25, iron 36.83,nickel 0.69, chromium 1.93, magnesium 4530441, sodium 54.13 and potassium 5.93 ng mg/sup -1/. It was observed that zinc, aluminum and potassium levels were higher than in calcium oxalate(CaOx) calculi 0.05>P>0.02 and potassium levels were higher than in mixed calcium oxalate-hydroxy appetite (CaOx/APA) calculi, P<0.01. A combination of all the results was also compared with similar data from South Africa, Turkey, Austria, India, U.S.A and Japan. (author)

  18. Content of zinc, iron, calcium and their absorption inhibitors in foods commonly consumed in Ethiopia

    NARCIS (Netherlands)

    Umeta, M.; West, C.E.; Fufa, H.


    The zinc, iron, calcium, phosphorus, phytate, tannin and moisture content of 36 foods consumed in rural Ethiopia were analysed. The foods analysed included those based on cereals, starchy tubers and roots, and legumes and vegetables as well as some fruits. Although many foods were relatively rich in

  19. Calcium hydroxide poisoning (United States)

    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 ...

  20. Kinetics of calcium sulfoaluminate formation from tricalcium aluminate, calcium sulfate and calcium oxide

    International Nuclear Information System (INIS)

    Li, Xuerun; Zhang, Yu; Shen, Xiaodong; Wang, Qianqian; Pan, Zhigang


    The formation kinetics of tricalcium aluminate (C 3 A) and calcium sulfate yielding calcium sulfoaluminate (C 4 A 3 $) and the decomposition kinetics of calcium sulfoaluminate were investigated by sintering a mixture of synthetic C 3 A and gypsum. The quantitative analysis of the phase composition was performed by X-ray powder diffraction analysis using the Rietveld method. The results showed that the formation reaction 3Ca 3 Al 2 O 6 + CaSO 4 → Ca 4 Al 6 O 12 (SO 4 ) + 6CaO was the primary reaction 4 Al 6 O 12 (SO 4 ) + 10CaO → 6Ca 3 Al 2 O 6 + 2SO 2 ↑ + O 2 ↑ primarily occurred beyond 1350 °C with an activation energy of 792 ± 64 kJ/mol. The optimal formation region for C 4 A 3 $ was from 1150 °C to 1350 °C and from 6 h to 1 h, which could provide useful information on the formation of C 4 A 3 $ containing clinkers. The Jander diffusion model was feasible for the formation and decomposition of calcium sulfoaluminate. Ca 2+ and SO 4 2− were the diffusive species in both the formation and decomposition reactions. -- Highlights: •Formation and decomposition of calcium sulphoaluminate were studied. •Decomposition of calcium sulphoaluminate combined CaO and yielded C 3 A. •Activation energy for formation was 231 ± 42 kJ/mol. •Activation energy for decomposition was 792 ± 64 kJ/mol. •Both the formation and decomposition were controlled by diffusion

  1. Why Calcium? How Calcium Became the Best Communicator* (United States)

    Carafoli, Ernesto; Krebs, Joachim


    Calcium carries messages to virtually all important functions of cells. Although it was already active in unicellular organisms, its role became universally important after the transition to multicellular life. In this Minireview, we explore how calcium ended up in this privileged position. Most likely its unique coordination chemistry was a decisive factor as it makes its binding by complex molecules particularly easy even in the presence of large excesses of other cations, e.g. magnesium. Its free concentration within cells can thus be maintained at the very low levels demanded by the signaling function. A large cadre of proteins has evolved to bind or transport calcium. They all contribute to buffer it within cells, but a number of them also decode its message for the benefit of the target. The most important of these “calcium sensors” are the EF-hand proteins. Calcium is an ambivalent messenger. Although essential to the correct functioning of cell processes, if not carefully controlled spatially and temporally within cells, it generates variously severe cell dysfunctions, and even cell death. PMID:27462077

  2. Codissolution of calcium hydrogenphosphate and sodium hydrogencitrate in water. Spontaneous supersaturation of calcium citrate increasing calcium bioavailability

    DEFF Research Database (Denmark)

    Hedegaard, Martina Vavrusova; Danielsen, Bente Pia; Garcia, André Castilho


    The sparingly soluble calcium hydrogenphosphate dihydrate, co-dissolving in water during dissolution of freely soluble sodium hydrogencitrate sesquihydrate as caused by proton transfer from hydrogencitrate to hydrogenphosphate, was found to form homogenous solutions supersaturated by a factor up...... to 8 in calcium citrate tetrahydrate. A critical hydrogencitrate concentration for formation of homogeneous solutions was found to depend linearly on dissolved calcium hydrogenphosphate: [HCitr2-] = 14[CaHPO4] - 0.05 at 25 °C. The lag phase for precipitation of calcium citrate tetrahydrate......, as identified from FT-IR spectra, from these spontaneously formed supersaturated solutions was several hours, and the time to reach solubility equilibrium was several days. Initial calcium ion activity was found to be almost independent of the degree of supersaturation as determined electrochemically...

  3. Calcium blood test (United States)

    ... page: // Calcium blood test To use the sharing features on this page, please enable JavaScript. The calcium blood test measures the level of calcium in the blood. ...

  4. Calcium carbonate overdose (United States)

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Products that contain calcium carbonate are certain: Antacids (Tums, Chooz) Mineral supplements Hand lotions Vitamin and mineral supplements Other products may also contain ...

  5. Calcium: the molecular basis of calcium action in biology and medicine

    National Research Council Canada - National Science Library

    Pochet, Roland; Donato, Rosario


    ... of Calcium Calcium Signalling in Excitable Cells Ca2+ Release in Muscle Cells by N. Macrez and J. Mironneau Calcium Signalling in Neurons Exemplified by Rat Sympathetic Ganglion Cells by S.J. M...

  6. Calcium source (image) (United States)

    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 ...

  7. Calcium ferrite formation from the thermolysis of calcium tris (maleato)

    Indian Academy of Sciences (India)

    For preparing calcium ferrite, calcium tris (maleato) ferrate(III) precursor was prepared by mixing aqueous solutions of iron(III) maleate, calcium maleate and maleic acid. Various physico-chemical techniques i.e. TG, DTG, DTA, Mössbauer, XRD, IR etc have been used to study the decomposition behaviour from ambient to ...

  8. The effect of habitat geology on calcium intake and calcium status of wild rodents. (United States)

    Shore, R F; Balment, R J; Yalden, D W


    Calcium is essential for normal physiological function, reproduction and growth in mammals but its distribution in the natural environment is heterogeneous. Spatial variation in calcium soil content is especially marked in the Peak District, United Kingdom, where both calcium-rich limestone and calcium-poor gritstone rock types occur. Wood mice Apodemus sylvaticus (L) and bank voles Clethrionomys glareolus (Schreber 1780) from limestone areas had significantly higher calcium concentrations in stomach contents and in faeces compared with their counterparts from gritstone areas. Calcium status was assessed from serum calcium concentration, femur weight, ash content of the body, calcium concentration in the femur and body ash. There was no significant difference in serum calcium concentration, femur calcium concentration and body ash calcium concentration between animals from the limestone and the gritstone. However, on the limestone, bank voles, but not wood mice, had significantly heavier femora and a greater proportion of ash in the body compared with their gritstone counterparts.

  9. Calcium fertilization increases the concentration of calcium in sapwood and calcium oxalate in foliage of red spruce (United States)

    Kevin T. Smith; Walter C. Shortle; Jon H. Connolly; Rakesh Minocha; Jody Jellison


    Calcium cycling plays a key role in the health and productivity of red spruce forests in the northeastern US. A portion of the flowpath of calcium within forests includes translocation as Ca2+ in sapwood and accumulation as crystals of calcium oxalate in foliage. Concentrations of Ca in these tree tissues have been used as markers of...

  10. Why Calcium? How Calcium Became the Best Communicator. (United States)

    Carafoli, Ernesto; Krebs, Joachim


    Calcium carries messages to virtually all important functions of cells. Although it was already active in unicellular organisms, its role became universally important after the transition to multicellular life. In this Minireview, we explore how calcium ended up in this privileged position. Most likely its unique coordination chemistry was a decisive factor as it makes its binding by complex molecules particularly easy even in the presence of large excesses of other cations, e.g. magnesium. Its free concentration within cells can thus be maintained at the very low levels demanded by the signaling function. A large cadre of proteins has evolved to bind or transport calcium. They all contribute to buffer it within cells, but a number of them also decode its message for the benefit of the target. The most important of these "calcium sensors" are the EF-hand proteins. Calcium is an ambivalent messenger. Although essential to the correct functioning of cell processes, if not carefully controlled spatially and temporally within cells, it generates variously severe cell dysfunctions, and even cell death. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. An overview of techniques for the measurement of calcium distribution, calcium fluxes, and cytosolic free calcium in mammalian cells

    International Nuclear Information System (INIS)

    Borle, A.B.


    An array of techniques can be used to study cell calcium metabolism that comprises several calcium compartments and many types of transport systems such as ion channels, ATP-dependent pumps, and antiporters. The measurement of total call calcium brings little information of value since 60 to 80% of total cell calcium is actually bound to the extracellular glycocalyx. Cell fractionation and differential centrifugation have been used to study intracellular Ca 2+ compartmentalization, but the methods suffer from the possibility of Ca 2+ loss or redistribution among cell fractions. Steady-state kinetic analyses of 45 Ca uptake or desaturation curves have been used to study the distribution of Ca 2+ among various kinetic pools in living cells and their rate of Ca 2+ exchange, but the analyses are constrained by many limitations. Nonsteady-state tracer studies can provide information about rapid changes in calcium influx or efflux in and out of the cell. Zero-time kinetics of 45 Ca uptake can detect instantaneous changes in calcium influx, while 45 Ca fractional efflux ratio, can detect rapid stimulations or inhibitions of calcium efflux out of cells. The best strategy to study cell calcium metabolism is to use several different methods that focus on a specific problem from widely different angles

  12. Development of poly(aspartic acid-co-malic acid) composites for calcium carbonate and sulphate scale inhibition. (United States)

    Mithil Kumar, N; Gupta, Sanjay Kumar; Jagadeesh, Dani; Kanny, K; Bux, F


    Polyaspartic acid (PSI) is suitable for the inhibition of inorganic scale deposition. To enhance its scale inhibition efficiency, PSI was modified by reacting aspartic acid with malic acid (MA) using thermal polycondensation polymerization. This reaction resulted in poly(aspartic acid-co-malic acid) (PSI-co-MA) dual polymer. The structural, chemical and thermal properties of the dual polymers were analysed by using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and gel permeation chromatography. The effectiveness of six different molar ratios of PSI-co-MA dual polymer for calcium carbonate and calcium sulphate scale inhibition at laboratory scale batch experiments was evaluated with synthetic brine solution at selected doses of polymer at 65-70°C by the static scale test method. The performance of PSI-co-MA dual polymer for the inhibition of calcium carbonate and calcium sulphate precipitation was compared with that of a PSI single polymer. The PSI-co-MA exhibited excellent ability to control inorganic minerals, with approximately 85.36% calcium carbonate inhibition and 100% calcium sulphate inhibition at a level of 10 mg/L PSI-co-MA, respectively. Therefore, it may be reasonably concluded that PSI-co-MA is a highly effective scale inhibitor for cooling water treatment applications.

  13. Calcium and Mitosis (United States)

    Hepler, P.


    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.

  14. Calcium ion binding properties of Medicago truncatula calcium/calmodulin-dependent protein kinase. (United States)

    Swainsbury, David J K; Zhou, Liang; Oldroyd, Giles E D; Bornemann, Stephen


    A calcium/calmodulin-dependent protein kinase (CCaMK) is essential in the interpretation of calcium oscillations in plant root cells for the establishment of symbiotic relationships with rhizobia and mycorrhizal fungi. Some of its properties have been studied in detail, but its calcium ion binding properties and subsequent conformational change have not. A biophysical approach was taken with constructs comprising either the visinin-like domain of Medicago truncatula CCaMK, which contains EF-hand motifs, or this domain together with the autoinhibitory domain. The visinin-like domain binds three calcium ions, leading to a conformational change involving the exposure of hydrophobic surfaces and a change in tertiary but not net secondary or quaternary structure. The affinity for calcium ions of visinin-like domain EF-hands 1 and 2 (K(d) = 200 ± 50 nM) was appropriate for the interpretation of calcium oscillations (~125-850 nM), while that of EF-hand 3 (K(d) ≤ 20 nM) implied occupancy at basal calcium ion levels. Calcium dissociation rate constants were determined for the visinin-like domain of CCaMK, M. truncatula calmodulin 1, and the complex between these two proteins (the slowest of which was 0.123 ± 0.002 s(-1)), suggesting the corresponding calcium association rate constants were at or near the diffusion-limited rate. In addition, the dissociation of calmodulin from the protein complex was shown to be on the same time scale as the dissociation of calcium ions. These observations suggest that the formation and dissociation of the complex between calmodulin and CCaMK would substantially mirror calcium oscillations, which typically have a 90 s periodicity.

  15. Calcium Carbonate (United States)

    ... Calcium is needed by the body for healthy bones, muscles, nervous system, and heart. Calcium carbonate also ... to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in ...

  16. Calcium en cardioplegie

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Meijler, F.L.


    Coronary perfusion with a calcium-free solution, followed by reperfusion with a calcium containing solution, may result in acute myocardial cell death and in irreversible loss of the e1ectrical and mechanical activity of the heart. This phenomenon is known as the calcium paradox. A number of

  17. Calcium Electroporation

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gibot, Laure; Madi, Moinecha


    BACKGROUND: Calcium electroporation describes the use of high voltage electric pulses to introduce supraphysiological calcium concentrations into cells. This promising method is currently in clinical trial as an anti-cancer treatment. One very important issue is the relation between tumor cell kill...... efficacy-and normal cell sensitivity. METHODS: Using a 3D spheroid cell culture model we have tested the effect of calcium electroporation and electrochemotherapy using bleomycin on three different human cancer cell lines: a colorectal adenocarcinoma (HT29), a bladder transitional cell carcinoma (SW780......), and a breast adenocarcinoma (MDA-MB231), as well as on primary normal human dermal fibroblasts (HDF-n). RESULTS: The results showed a clear reduction in spheroid size in all three cancer cell spheroids three days after treatment with respectively calcium electroporation (p

  18. Effect of calcium intake on urinary oxalate excretion in calcium stone-forming patients

    Directory of Open Access Journals (Sweden)

    Nishiura J.L.


    Full Text Available Dietary calcium lowers the risk of nephrolithiasis due to a decreased absorption of dietary oxalate that is bound by intestinal calcium. The aim of the present study was to evaluate oxaluria in normocalciuric and hypercalciuric lithiasic patients under different calcium intake. Fifty patients (26 females and 24 males, 41 ± 10 years old, whose 4-day dietary records revealed a regular low calcium intake (<=500 mg/day, received an oral calcium load (1 g/day for 7 days. A 24-h urine was obtained before and after load and according to the calciuria under both diets, patients were considered as normocalciuric (NC, N = 15, diet-dependent hypercalciuric (DDHC, N = 9 or diet-independent hypercalciuric (DIHC, N = 26. On regular diet, mean oxaluria was 30 ± 14 mg/24 h for all patients. The 7-day calcium load induced a significant decrease in mean oxaluria compared to the regular diet in NC and DIHC (20 ± 12 vs 26 ± 7 and 27 ± 18 vs 32 ± 15 mg/24 h, respectively, P<0.05 but not in DDHC patients (22 ± 10 vs 23 ± 5 mg/24 h. The lack of an oxalate decrease among DDHC patients after the calcium load might have been due to higher calcium absorption under higher calcium supply, with a consequent lower amount of calcium left in the intestine to bind with oxalate. These data suggest that a long-lasting regular calcium consumption <500 mg was not associated with high oxaluria and that a subpopulation of hypercalciuric patients who presented a higher intestinal calcium absorption (DDHC tended to hyperabsorb oxalate as well, so that oxaluria did not change under different calcium intake.

  19. Calcium - ionized (United States)

    ... diuretics Thrombocytosis (high platelet count) Tumors Vitamin A excess Vitamin D excess Lower-than-normal levels may be due to: Hypoparathyroidism Malabsorption Osteomalacia Pancreatitis Renal failure Rickets Vitamin D deficiency Alternative Names Free calcium; Ionized calcium ...

  20. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Recker, R.R.


    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  1. Study of calcium chloride and calcium nitrate purification on inorganic sorbents

    International Nuclear Information System (INIS)

    Vasil'eva, L.V.; Knyazeva, A.N.; Fakeev, A.A.; Belyaeva, N.A.; Morozov, V.I.; Kucherova, V.V.


    Purification of calcium chloride and calcium nitrate from iron, chromium, manganese and cobalt impurities by sorption on some inorganic collectors are considered in this article. Study was conducted by means of radioactive-tracer technique at concurrent use of several γ-radioactive isotopes. As a collectors were used hydrated aluminium and zirconium oxides. Dependence of effectiveness of precipitation by collectors on ph-value of medium, quantity of collector, nature and concentration of components is studied. Optimal parameters of purification of calcium chloride and calcium nitrate are defined.

  2. Atomic layer deposition of calcium oxide and calcium hafnium oxide films using calcium cyclopentadienyl precursor

    International Nuclear Information System (INIS)

    Kukli, Kaupo; Ritala, Mikko; Sajavaara, Timo; Haenninen, Timo; Leskelae, Markku


    Calcium oxide and calcium hafnium oxide thin films were grown by atomic layer deposition on borosilicate glass and silicon substrates in the temperature range of 205-300 o C. The calcium oxide films were grown from novel calcium cyclopentadienyl precursor and water. Calcium oxide films possessed refractive index 1.75-1.80. Calcium oxide films grown without Al 2 O 3 capping layer occurred hygroscopic and converted to Ca(OH) 2 after exposure to air. As-deposited CaO films were (200)-oriented. CaO covered with Al 2 O 3 capping layers contained relatively low amounts of hydrogen and re-oriented into (111) direction upon annealing at 900 o C. In order to examine the application of CaO in high-permittivity dielectric layers, mixtures of Ca and Hf oxides were grown by alternate CaO and HfO 2 growth cycles at 230 and 300 o C. HfCl 4 was used as a hafnium precursor. When grown at 230 o C, the films were amorphous with equal amounts of Ca and Hf constituents (15 at.%). These films crystallized upon annealing at 750 o C, showing X-ray diffraction peaks characteristic of hafnium-rich phases such as Ca 2 Hf 7 O 16 or Ca 6 Hf 19 O 44 . At 300 o C, the relative Ca content remained below 8 at.%. The crystallized phase well matched with rhombohedral Ca 2 Hf 7 O 16 . The dielectric films grown on Si(100) substrates possessed effective permittivity values in the range of 12.8-14.2

  3. Calcium sensing in exocytosis

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Wu, Bingbing; Han, Weiping


    an increase in intracellular calcium levels. Besides the triggering role, calcium signaling modulates the precise amount and kinetics of vesicle release. Thus, it is a central question to understand the molecular machineries responsible for calcium sensing in exocytosis. Here we provide an overview of our...... current understanding of calcium sensing in neurotransmitter release and hormone secretion....

  4. Prediagnostic serum calcium and albumin and ovarian cancer: A nested case-control study in the Norwegian Janus Serum Bank Cohort. (United States)

    Schwartz, Gary G; Tretli, Steinar; Vos, Linda; Robsahm, Trude E


    Women with higher serum calcium may be more likely to be diagnosed and die of ovarian cancer. We evaluated that finding in a large, prospective cohort. We conducted a nested case-control study using a population-based biobank from Norway. We compared 202 ovarian cancer cases and 202 controls, matched for age, date at blood draw, and county of residence, with respect to serum calcium and albumin, adjusted for anthropometric variables. We evaluated risks using the entire follow-up period as well as 2-15 years and 16-25 years ("early" and "late", respectively). For the entire follow-up, risk was significantly increased in the highest tertile of albumin and for high albumin and calcium jointly. Risks for ovarian cancer differed markedly by follow-up time. In early follow-up, women in the highest tertile of serum calcium had a 2.5-fold increased risk, adjusted for height and body mass index (OR=2.47, 95% C.I. 1.12-5.45) with a significant dose-response (p=0.024). Risk was not elevated in late follow-up (OR=0.62, 95% C.I. 0.27-1.36). Similarly, in early follow-up, women in the highest tertile of serum albumin had an increased risk (OR=2.55, 95% C.I.1.22-5.49) with a significant dose-response (p=0.009). Conversely, risk was not increased in late follow-up (OR=1.36, 95% C.I. 0.65-2.83). These data confirm a prospective association between higher serum calcium and ovarian cancer. An association in early, but not late, follow-up suggests that the higher calcium reflects the presence of existing cancer. A positive association with serum albumin is novel and should be interpreted cautiously. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.


    International Nuclear Information System (INIS)

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


    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 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

  6. Estimation of ionized calcium, total calcium and albumin corrected calcium for the diagnosis of hypocalcaemia of malignancy

    International Nuclear Information System (INIS)

    Ijaz, A.; Mehmood, T.; Qureshi, A.H.; Anwar, M.; Dilawar, M.; Hussain, I.; Khan, F.A.; Khan, D.A.; Hussain, S.; Khan, I.A.


    Objective: To measure levels of ionized calcium, total calcium and albumin corrected calcium in patients with different malignant disorders for the diagnosis of hypercalcaemia of malignancy. Design: A case control comparative study. Place and Duration of Study: The study was carried out in the Department of Pathology, Army Medical College Rawalpindi, Armed Forces Institute of Pathology and Department of Oncology CMH, Rawalpindi from March 2003 to December 2003. Subjects and Methods: Ninety-seven patients of various malignant disorders, admitted in the Department of Oncology, CMH, Rawalpindi, and 39 age and gender-matched disease-free persons (as control) were included in the study. Blood ionized calcium (Ca/sup ++/), pH, sodium (Na/sup +/) and potassium (K/sup +/) were analysed by Ion selective electrode (ISE) on Easylyte> auto analyser. Other related parameters were measured by colorimetric methods. Results: Blood Ca/sup ++/ levels in patients suffering from malignant disorders were found significantly high (mean +- j 1.30+017 mmoV/L) as compared to control subjects (mean +- 1.23+0.03 mmoV/L) (p<0.001). The number of patients with hypercalcaemia of malignancy detected by Ca/sup ++/ estimation was significantly higher (38%) as compared to total calcium (8.4%) and albumin corrected calcium ACC (10.6%) (p<0.001). There was no statistically significant difference in other parameters e.g. phosphate, urea, creatinine, pH, Na/sup +/ and K/sup +/ levels in study subjects and controls. Conclusion: Detection of hypercalcaemia can be markedly improved if ionized calcium estimation is used in patients with malignant disorders. (author)

  7. SR calcium handling and calcium after-transients in a rabbit model of heart failure

    NARCIS (Netherlands)

    Baartscheer, Antonius; Schumacher, Cees A.; Belterman, Charly N. W.; Coronel, Ruben; Fiolet, Jan W. T.


    Objective: After-depolarization associated arrhythmias are frequently observed in heart failure and associated with spontaneous calcium release from sarcoplasmic reticulum (SR), calcium after-transients. We hypothesize that disturbed SR calcium handling underlies calcium after-transients in heart

  8. Calcium absorption from fortified ice cream formulations compared with calcium absorption from milk. (United States)

    van der Hee, Regine M; Miret, Silvia; Slettenaar, Marieke; Duchateau, Guus S M J E; Rietveld, Anton G; Wilkinson, Joy E; Quail, Patricia J; Berry, Mark J; Dainty, Jack R; Teucher, Birgit; Fairweather-Tait, Susan J


    Optimal bone mass in early adulthood is achieved through appropriate diet and lifestyle, thereby protecting against osteoporosis and risk of bone fracture in later life. Calcium and vitamin D are essential to build adequate bones, but calcium intakes of many population groups do not meet dietary reference values. In addition, changes in dietary patterns are exacerbating the problem, thereby emphasizing the important role of calcium-rich food products. We have designed a calcium-fortified ice cream formulation that is lower in fat than regular ice cream and could provide a useful source of additional dietary calcium. Calcium absorption from two different ice cream formulations was determined in young adults and compared with milk. Sixteen healthy volunteers (25 to 45 years of age), recruited from the general public of The Netherlands, participated in a randomized, reference-controlled, double-blind cross-over study in which two test products and milk were consumed with a light standard breakfast on three separate occasions: a standard portion of ice cream (60 g) fortified with milk minerals and containing a low level (3%) of butter fat, ice cream (60 g) fortified with milk minerals and containing a typical level (9%) of coconut oil, and reduced-fat milk (1.7% milk fat) (200 mL). Calcium absorption was measured by the dual-label stable isotope technique. Effects on calcium absorption were evaluated by analysis of variance. Fractional absorption of calcium from the 3% butterfat ice cream, 9% coconut oil ice cream, and milk was 26%+/-8%, 28%+/-5%, and 31%+/-9%, respectively, and did not differ significantly (P=0.159). Results indicate that calcium bioavailability in the two calcium-fortified ice cream formulations used in this study is as high as milk, indicating that ice cream may be a good vehicle for delivery of calcium.

  9. Uptake of radiactive calcium by groundnut (Arachis hypogaea L. ) and efficiency of utilisation of applied calcium

    Energy Technology Data Exchange (ETDEWEB)

    Loganathan, S; Krishnamoorthy, K K [Tamil Nadu Agricultural Univ., Coimbatore (India). Dept. of Soil Science and Agricultural Chemistry


    A pot experiment was conducted with groundnut applying labelled calcium as its sulphate and carbonate at two levels namely 75 and 150 kg Ca per ha with varying levels of P, K and Mg. Plant samples were taken at different stages of crop growth and analysed for the content of radioactive calcium. Calcium sulphate treatment has resulted in larger uptake of calcium compared to calcium carbonate. An application of 150 kg Ca per ha has caused significantly higher uptake by groundnut plant than 75 kg Ca per ha. The percentage of utilisation of added calcium ranged from 2.2 to 5.4 Recovery of calcium by plants was more in calcium sulphate treatment rather than in calcium carbonate. The plants showed a preference for absorbing applied calcium rather than native calcium.

  10. Uptake of radiactive calcium by groundnut (Arachis hypogaea L.) and efficiency of utilisation of applied calcium

    International Nuclear Information System (INIS)

    Loganathan, S.; Krishnamoorthy, K.K.


    A pot experiment was conducted with groundnut applying labelled calcium as its sulphate and carbonate at two levels namely 75 and 150 kg Ca per ha with varying levels of P, K and Mg. Plant samples were taken at different stages of crop growth and analysed for the content of radioactive calcium. Calcium sulphate treatment has resulted in larger uptake of calcium compared to calcium carbonate. An application of 150 kg Ca per ha has caused significantly higher uptake by groundnut plant than 75 kg Ca per ha. The percentage of utilisation of added calcium ranged from 2.2 to 5.4 Recovery of calcium by plants was more in calcium sulphate treatment rather than in calcium carbonate. The plants showed a preference for absorbing applied calcium rather than native calcium

  11. Intravascular ultrasound evaluation of JETSTREAM atherectomy removal of superficial calcium in peripheral arteries. (United States)

    Maehara, Akiko; Mintz, Gary S; Shimshak, Thomas M; Ricotta, Joseph J; Ramaiah, Venkatesh; Foster, Malcolm T; Davis, Thomas P; Gray, William A


    Endovascular treatment of calcified femoral-popliteal disease is challenging. We sought to evaluate the mechanism of lumen gain when using the JETSTREAM Atherectomy System to treat calcified peripheral artery lesions. The JETSTREAM Calcium Study was a prospective, single-arm, multicentre study to evaluate the JETSTREAM Atherectomy System for severely calcified femoral-popliteal artery lesions, i.e., patients with claudication and lesions with superficial calcium >90° and >5 mm in length as determined by intravascular ultrasound (IVUS). The 2.1 mm catheter was used in this study without distal protection. Fifty-five patients underwent angiographic screening: 26 (45%) met IVUS inclusion criteria. Angiographic calcium was moderate in eight cases and severe in 14, with no available data for four cases. Visual diameter stenosis was 86±9% pre-treatment, 37±13% post atherectomy, and 10±6% post adjunctive treatment (adjunctive PTA+stenting in eight and adjunct PTA alone in 16). IVUS showed lumen area increased from 6.6±3.7 mm2 to 10.0±3.6 mm2 (p=0.001): calcium reduction was responsible for 86±23% of the lumen increase. Although the superficial calcium arc did not change (151±70° to 146±71°, p=0.83), the arc of reverberation increased (23±20° to 65±40°, p=0.006), indicating device-related modification of calcium. Adjunctive balloon angioplasty was performed in 62% of the lesions, and stent implantation in 31%. In 11 cases with adjunctive balloon dilation, the MLA increased from 7.1 (6.4, 7.8) mm2 post atherectomy to 11.9 (10.3, 13.5) mm2 post balloon (pAtherectomy System increased lumen dimensions in moderately or severely calcified femoral-popliteal lesions by removing superficial calcium without major complications.

  12. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau


    Full Text Available The paper gives the review on the role of calcium in many physiological processes of plant organisms, including growth and development, protection from pathogenic influences, response to changing environmental factors, and many other aspects of plant physiology. Initial intake of calcium ions is carried out by Ca2+-channels of plasma membrane and they are further transported by the xylem owing to auxins’ attractive ability. The level of intake and selectivity of calcium transport to ove-ground parts of the plant is controlled by a symplast. Ca2+enters to the cytoplasm of endoderm cells through calcium channels on the cortical side of Kaspary bands, and is redistributed inside the stele by the symplast, with the use of Ca2+-АТPases and Ca2+/Н+-antiports. Owing to regulated expression and activity of these calcium transporters, calclum can be selectively delivered to the xylem. Important role in supporting calcium homeostasis is given to the vacuole which is the largest depo of calcium. Regulated quantity of calcium movement through the tonoplast is provided by a number of potential-, ligand-gated active transporters and channels, like Ca2+-ATPase and Ca2+/H+ exchanger. They are actively involved in the inactivation of the calcium signal by pumping Ca2+ to the depo of cells. Calcium ATPases are high affinity pumps that efficiently transfer calcium ions against the concentration gradient in their presence in the solution in nanomolar concentrations. Calcium exchangers are low affinity, high capacity Ca2+ transporters that are effectively transporting calcium after raising its concentration in the cell cytosol through the use of protons gradients. Maintaining constant concentration and participation in the response to stimuli of different types also involves EPR, plastids, mitochondria, and cell wall. Calcium binding proteins contain several conserved sequences that provide sensitivity to changes in the concentration of Ca2+ and when you

  13. An Exploration of the Calcium-Binding Mode of Egg White Peptide, Asp-His-Thr-Lys-Glu, and In Vitro Calcium Absorption Studies of Peptide-Calcium Complex. (United States)

    Sun, Na; Jin, Ziqi; Li, Dongmei; Yin, Hongjie; Lin, Songyi


    The binding mode between the pentapeptide (DHTKE) from egg white hydrolysates and calcium ions was elucidated upon its structural and thermodynamics characteristics. The present study demonstrated that the DHTKE peptide could spontaneously bind calcium with a 1:1 stoichiometry, and that the calcium-binding site corresponded to the carboxyl oxygen, amino nitrogen, and imidazole nitrogen atoms of the DHTKE peptide. Moreover, the effect of the DHTKE-calcium complex on improving the calcium absorption was investigated in vitro using Caco-2 cells. Results showed that the DHTKE-calcium complex could facilitate the calcium influx into the cytosol and further improve calcium absorption across Caco-2 cell monolayers by more than 7 times when compared to calcium-free control. This study facilitates the understanding about the binding mechanism between peptides and calcium ions as well as suggests a potential application of egg white peptides as nutraceuticals to improve calcium absorption.

  14. Calcium carbonate scaling kinetics determined from radiotracer experiments with calcium-47

    International Nuclear Information System (INIS)

    Turner, C.W.; Smith, D.W.


    The deposition rate of calcium carbonate on a heat-transfer surface has been measured using a calcium-47 radiotracer and compared to the measured rate of thermal fouling. The crystalline phase of calcium carbonate that precipitates depends on the degree of supersaturation at the heat-transfer surface, with aragonite precipitating at higher supersaturations and calcite precipitating at lower supersaturations. Whereas the mass deposition rates were constant with time, the thermal fouling rates decreased throughout the course of each experiment as a result of densification of the deposit. It is proposed that the densification was driven by the temperature gradient across the deposit together with the retrograde solubility of calcium carbonate. The temperature dependence of the deposition rate yielded an activation energy of 79 ± 4 kJ/mol for the precipitation of calcium carbonate on a heat-transfer surface. (author)

  15. Calcium Signaling in Taste Cells (United States)

    Medler, Kathryn F.


    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

  16. Calcium Pyrophosphate Deposition (CPPD) (United States)

    ... Patient / Caregiver Diseases & Conditions Calcium Pyrophosphate Deposition (CPPD) Calcium Pyrophosphate Deposition (CPPD) Fast Facts The risk of ... young people, too. Proper diagnosis depends on detecting calcium pyrophosphate crystals in the fluid of an affected ...

  17. Calcium and bones (image) (United States)

    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 channel blocker poisoning

    Directory of Open Access Journals (Sweden)

    Miran Brvar


    Full Text Available Background: Calcium channel blockers act at L-type calcium channels in cardiac and vascular smooth muscles by preventing calcium influx into cells with resultant decrease in vascular tone and cardiac inotropy, chronotropy and dromotropy. Poisoning with calcium channel blockers results in reduced cardiac output, bradycardia, atrioventricular block, hypotension and shock. The findings of hypotension and bradycardia should suggest poisoning with calcium channel blockers.Conclusions: Treatment includes immediate gastric lavage and whole-bowel irrigation in case of ingestion of sustainedrelease products. All patients should receive an activated charcoal orally. Specific treatment includes calcium, glucagone and insulin, which proved especially useful in shocked patients. Supportive care including the use of catecholamines is not always effective. In the setting of failure of pharmacological therapy transvenous pacing, balloon pump and cardiopulmonary by-pass may be necessary.

  19. The Hepatitis B Virus X Protein Elevates Cytosolic Calcium Signals by Modulating Mitochondrial Calcium Uptake (United States)

    Yang, Bei


    Chronic hepatitis B virus (HBV) infections are associated with the development of hepatocellular carcinoma (HCC). The HBV X protein (HBx) is thought to play an important role in the development of HBV-associated HCC. One fundamental HBx function is elevation of cytosolic calcium signals; this HBx activity has been linked to HBx stimulation of cell proliferation and transcription pathways, as well as HBV replication. Exactly how HBx elevates cytosolic calcium signals is not clear. The studies described here show that HBx stimulates calcium entry into cells, resulting in an increased plateau level of inositol 1,4,5-triphosphate (IP3)-linked calcium signals. This increased calcium plateau can be inhibited by blocking mitochondrial calcium uptake and store-operated calcium entry (SOCE). Blocking SOCE also reduced HBV replication. Finally, these studies also demonstrate that there is increased mitochondrial calcium uptake in HBx-expressing cells. Cumulatively, these studies suggest that HBx can increase mitochondrial calcium uptake and promote increased SOCE to sustain higher cytosolic calcium and stimulate HBV replication. PMID:22031934

  20. Effect of anions or foods on absolute bioavailability of calcium from calcium salts in mice by pharmacokinetics


    Zenei Taira, Zenei; Ueda,Yukari


    Yukari Ueda, Zenei TairaFaculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, JapanAbstract: We studied the absolute bioavailability of calcium from calcium L-lactate in mice using pharmacokinetics, and reviewed the absolute bioavailability of calcium from three other calcium salts in mice previously studied: calcium chloride, calcium acetate, and calcium ascorbate. The results showed that calcium metabolism is linear between intravenous administration of 15 mg/kg and 30 ...

  1. Voltage-Gated Calcium Channels (United States)

    Zamponi, Gerald Werner

    Voltage Gated Calcium Channels is the first comprehensive book in the calcium channel field, encompassing over thirty years of progress towards our understanding of calcium channel structure, function, regulation, physiology, pharmacology, and genetics. This book balances contributions from many of the leading authorities in the calcium channel field with fresh perspectives from risings stars in the area, taking into account the most recent literature and concepts. This is the only all-encompassing calcium channel book currently available, and is an essential resource for academic researchers at all levels in the areas neuroscience, biophysics, and cardiovascular sciences, as well as to researchers in the drug discovery area.

  2. Dietary Calcium Intake and Adherence to the Mediterranean Diet in Spanish Children: The ANIVA Study

    Directory of Open Access Journals (Sweden)

    Nuria Rubio-López


    Full Text Available The aim of this study was to evaluate the relationship of dietary calcium intake with anthropometric measures, physical activity and adherence to the Mediterranean diet (MedDiet in 1176 Spanish children aged 6–9 years. Data were obtained from “Antropometría y Nutrición Infantil de Valencia” (ANIVA, a cross-sectional study of a representative sample. Dietary calcium intake assessed from three-day food records was compared to recommended daily intakes in Spain. Anthropometric measures (weight and height were measured according to international standards and adherence to the MedDiet was evaluated using the Mediterranean Diet Quality Index (KIDMED test. For the total sample of children, 25.8% had inadequate calcium intake, a significantly higher prevalence in girls (p = 0.006 and inadequate calcium intake was associated with lower height z-score (p = 0.001 for both sexes. In girls, there was an inverse relationship between calcium intake and body mass index (p = 0.001 and waist/hip ratio (p = 0.018. Boys presented a polarization in physical activity, reporting a greater level of both physical and sedentary activity in comparison with girls (p = 0.001. Children with poor adherence to MedDiet, even if they consume two yogurts or cheese (40 g daily, adjusted by gender, age, total energy intake, physical activity and father’s level of education, are at risk of inadequate total calcium intake (odds ratio adjusted [ORa]: 3.36, 95% confidence interval [CI]: 1.13–9.94, p = 0.001. The intake of these dairy products was insufficient to cover calcium intake recommendations in this age group (6–9 years. It is important to prioritize health strategies that promote the MedDiet and to increase calcium intake in this age group.

  3. The influence of calcium-45 on the inhibitive effect of calcium hexameta-phosphate combination and the electrocapillary effect of calcium-45

    International Nuclear Information System (INIS)

    Subramanyan, N.; Venkatakrishna Iyer, S.; Kapali, V.


    Corrosion of steel in an aqueous chloride solution is significantly accelerated if calcium (NaHMP)-45 is substituted for ordinary calcium when calcium and sodium metaphosphate combination was investigated for inhibiting action. In this investigation it is seen that the anodic polarisation of steel is brought down when 45 Ca is present in the different solutions containing Ca, non radioactive calcium and (NaHMP) at pH 5.5, 7.5 and 9.0 except in one case when 45 Ca is present alone in the solution of pH 5.5. The uptake of 45 Ca is more at the positive potentials than at the negative. Electrocapillary measurements with calcium chloride solution show that the electrocapillary curve is lifted above that for the base solution particularly on the positive side of the electrocapillary maximum. These interesting observations are explained by the postulate that radioactive calcium behaves like an anion and the acceleration of corrosion is attributed essentially to radiolytically produced hydrogen peroxide. (author)

  4. Calcium binding by dietary fibre

    International Nuclear Information System (INIS)

    James, W.P.T.; Branch, W.J.; Southgate, D.A.T.


    Dietary fibre from plants low in phytate bound calcium in proportion to its uronic-acid content. This binding by the non-cellulosic fraction of fibre reduces the availability of calcium for small-intestinal absorption, but the colonic microbial digestion of uronic acids liberates the calcium. Thus the ability to maintain calcium balance on high-fibre diets may depend on the adaptive capacity on the colon for calcium. (author)

  5. Development and molecular characterization of genic molecular markers for grain protein and calcium content in finger millet (Eleusine coracana (L.) Gaertn.). (United States)

    Nirgude, M; Babu, B Kalyana; Shambhavi, Y; Singh, U M; Upadhyaya, H D; Kumar, Anil


    Finger millet (Eleusine coracana (L.) Gaertn), holds immense agricultural and economic importance for its high nutraceuticals quality. Finger millets seeds are rich source of calcium and its proteins are good source of essential amino acids. In the present study, we developed 36 EST-SSR primers for the opaque2 modifiers and 20 anchored-SSR primers for calcium transporters and calmodulin for analysis of the genetic diversity of 103 finger millet genotypes for grain protein and calcium contents. Out of the 36 opaque2 modifiers primers, 15 were found polymorphic and were used for the diversity analysis. The highest PIC value was observed with the primer FMO2E33 (0.26), while the lowest was observed FMO2E27 (0.023) with an average value of 0.17. The gene diversity was highest for the primer FMO2E33 (0.33), however it was lowest for FMO2E27 (0.024) at average value of 0.29. The percentage polymorphism shown by opaque2 modifiers primers was 68.23%. The diversity analysis by calcium transporters and calmodulin based anchored SSR loci revealed that the highest PIC was observed with the primer FMCA8 (0.30) and the lowest was observed for FMCA5 (0.023) with an average value of 0.18. The highest gene diversity was observed for primer FMCA8 (0.37), while lowest for FMCA5 (0.024) at an average of 0.21. The opaque2 modifiers specific EST-SSRs could able to differentiate the finger millet genotypes into high, medium and low protein containing genotypes. However, calcium dependent candidate gene based EST-SSRs could broadly differentiate the genotypes based on the calcium content with a few exceptions. A significant negative correlation between calcium and protein content was observed. The present study resulted in identification of highly polymorphic primers (FMO2E30, FMO2E33, FMO2-18 and FMO2-14) based on the parameters such as percentage of polymorphism, PIC values, gene diversity and number of alleles.

  6. Dengue and Calcium


    Shivanthan, Mitrakrishnan C; Rajapakse, Senaka


    Dengue is potentially fatal unless managed appropriately. No specific treatment is available and the mainstay of treatment is fluid management with careful monitoring, organ support, and correction of metabolic derangement. Evidence with regards to the role of calcium homeostasis in dengue is limited. Low blood calcium levels have been demonstrated in dengue infection and hypocalcemia maybe more pronounced in more severe forms. The cause of hypocalcemia is likely to be multifactorial. Calcium...

  7. Synthesis of calcium hydroxyapatite from calcium carbonate and different orthophosphate sources: A comparative study

    International Nuclear Information System (INIS)

    Pham Minh, Doan; Lyczko, Nathalie; Sebei, Haroun; Nzihou, Ange; Sharrock, Patrick


    Highlights: ► Calcium hydroxyapatite was synthesized from CaCO 3 and four orthophosphates. ► Only H 3 PO 4 led to the complete precipitation of orthophosphate species. ► H 3 PO 4 was also the most efficient for calcium dissolution. ► Reaction pathway was dissolution-precipitation accompanied by agglomeration step. - Abstract: The synthesis of calcium hydroxyapatite (Ca-HA) starting from calcium carbonate and different orthophosphate sources, including orthophosphoric acid, potassium, sodium and ammonium dihydrogen orthophosphates, was investigated under ambient conditions. The reaction started with calcium carbonate dissolution in an acid medium, followed by rapid precipitation of calcium cations with orthophosphate species to form calcium phosphate based particles which were in the size range of 0.4–1 μm. These particles then agglomerated into much larger ones, up to 350 μm in diameter (aggregates). These aggregates possessed an unstable porous structure which was responsible for the porosity of the final products. The highest specific surface area and pore volume were obtained with potassium dihydrogen orthophosphate. On the other hand, orthophosphoric acid led to the highest dissolution of calcium carbonate and the complete precipitation of orthophosphate species. Under ambient conditions, calcium phosphate based solid products of low crystallinity were formed. Different intermediates were identified and a reaction pathway proposed.

  8. Testosterone increases urinary calcium excretion and inhibits expression of renal calcium transport proteins.

    NARCIS (Netherlands)

    Hsu, Y.J.; Dimke, H.; Schoeber, J.P.H.; Hsu, S.C.; Lin, S.H.; Chu, P.; Hoenderop, J.G.J.; Bindels, R.J.M.


    Although gender differences in the renal handling of calcium have been reported, the overall contribution of androgens to these differences remains uncertain. We determined here whether testosterone affects active renal calcium reabsorption by regulating calcium transport proteins. Male mice had

  9. Calcium metabolism in birds. (United States)

    de Matos, Ricardo


    Calcium is one of the most important plasma constituents in mammals and birds. It provides structural strength and support (bones and eggshell) and plays vital roles in many of the biochemical reactions in the body. The control of calcium metabolism in birds is highly efficient and closely regulated in a number of tissues, primarily parathyroid gland, intestine, kidney, and bone. The hormones with the greatest involvement in calcium regulation in birds are parathyroid hormone, 1,25-dihydroxyvitamin D(3) (calcitriol), and estrogen, with calcitonin playing a minor and uncertain role. The special characteristics of calcium metabolism in birds, mainly associated with egg production, are discussed, along with common clinical disorders secondary to derangements in calcium homeostasis.

  10. Calcium Balance in Chronic Kidney Disease. (United States)

    Hill Gallant, Kathleen M; Spiegel, David M


    The kidneys play a critical role in the balance between the internal milieu and external environment. Kidney failure is known to disrupt a number of homeostatic mechanisms that control serum calcium and normal bone metabolism. However, our understanding of calcium balance throughout the stages of chronic kidney disease is limited and the concept of balance itself, especially with a cation as complex as calcium, is often misunderstood. Both negative and positive calcium balance have important implications in patients with chronic kidney disease, where negative balance may increase risk of osteoporosis and fracture and positive balance may increase risk of vascular calcification and cardiovascular events. Here, we examine the state of current knowledge about calcium balance in adults throughout the stages of chronic kidney disease and discuss recommendations for clinical strategies to maintain balance as well as future research needs in this area. Recent calcium balance studies in adult patients with chronic kidney disease show that neutral calcium balance is achieved with calcium intake near the recommended daily allowance. Increases in calcium through diet or supplements cause high positive calcium balance, which may put patients at risk for vascular calcification. However, heterogeneity in calcium balance exists among these patients. Given the available calcium balance data in this population, it appears clinically prudent to aim for recommended calcium intakes around 1000 mg/day to achieve neutral calcium balance and avoid adverse effects of either negative or positive calcium balance. Assessment of patients' dietary calcium intake could further equip clinicians to make individualized recommendations for meeting recommended intakes.

  11. Fenoprofen calcium overdose (United States)

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

  12. Effect of oral calcium and calcium + fluoride treatments on mouse bone properties during suspension (United States)

    Simske, S. J.; Luttges, M. W.; Allen, K. A.; Spooner, B. S. (Principal Investigator)


    The bone effects of oral dosages of calcium chloride with or without supplementary sodium fluoride were assessed in antiorthostatically suspended mice. Two calcium dosages were used to replace half (3.1 mM) or all(6.3 mM) of the dietary calcium lost due to reduced food intake by the suspended mice. Two groups of 6.3 mM CaCl2-treated mice were additionally treated with 0.25 or 2.5 mM NaF. The results indicate that supplementation of the mouse drinking water with calcium salts prevents bone changes induced by short-term suspension, while calcium salts in combination with fluoride are less effective as fluoride dosage increases. However, the calcium supplements change the relationship between the femur mechanical properties and the mineral composition of the bone. Because of this, it appears that oral calcium supplements are effective through a mechanism other than simple dietary supplementation and may indicate a dependence of bone consistency on systemic and local fluid conditions.

  13. Structures of apicomplexan calcium-dependent protein kinases reveal mechanism of activation by calcium

    Energy Technology Data Exchange (ETDEWEB)

    Wernimont, Amy K; Artz, Jennifer D.; Jr, Patrick Finerty; Lin, Yu-Hui; Amani, Mehrnaz; Allali-Hassani, Abdellah; Senisterra, Guillermo; Vedadi, Masoud; Tempel, Wolfram; Mackenzie, Farrell; Chau, Irene; Lourido, Sebastian; Sibley, L. David; Hui, Raymond (Toronto); (WU-MED)


    Calcium-dependent protein kinases (CDPKs) have pivotal roles in the calcium-signaling pathway in plants, ciliates and apicomplexan parasites and comprise a calmodulin-dependent kinase (CaMK)-like kinase domain regulated by a calcium-binding domain in the C terminus. To understand this intramolecular mechanism of activation, we solved the structures of the autoinhibited (apo) and activated (calcium-bound) conformations of CDPKs from the apicomplexan parasites Toxoplasma gondii and Cryptosporidium parvum. In the apo form, the C-terminal CDPK activation domain (CAD) resembles a calmodulin protein with an unexpected long helix in the N terminus that inhibits the kinase domain in the same manner as CaMKII. Calcium binding triggers the reorganization of the CAD into a highly intricate fold, leading to its relocation around the base of the kinase domain to a site remote from the substrate binding site. This large conformational change constitutes a distinct mechanism in calcium signal-transduction pathways.

  14. Live Imaging of Calcium Dynamics during Axon Degeneration Reveals Two Functionally Distinct Phases of Calcium Influx (United States)

    Yamagishi, Yuya; Tessier-Lavigne, Marc


    Calcium is a key regulator of axon degeneration caused by trauma and disease, but its specific spatial and temporal dynamics in injured axons remain unclear. To clarify the function of calcium in axon degeneration, we observed calcium dynamics in single injured neurons in live zebrafish larvae and tested the temporal requirement for calcium in zebrafish neurons and cultured mouse DRG neurons. Using laser axotomy to induce Wallerian degeneration (WD) in zebrafish peripheral sensory axons, we monitored calcium dynamics from injury to fragmentation, revealing two stereotyped phases of axonal calcium influx. First, axotomy triggered a transient local calcium wave originating at the injury site. This initial calcium wave only disrupted mitochondria near the injury site and was not altered by expression of the protective WD slow (WldS) protein. Inducing multiple waves with additional axotomies did not change the kinetics of degeneration. In contrast, a second phase of calcium influx occurring minutes before fragmentation spread as a wave throughout the axon, entered mitochondria, and was abolished by WldS expression. In live zebrafish, chelating calcium after the first wave, but before the second wave, delayed the progress of fragmentation. In cultured DRG neurons, chelating calcium early in the process of WD did not alter degeneration, but chelating calcium late in WD delayed fragmentation. We propose that a terminal calcium wave is a key instructive component of the axon degeneration program. SIGNIFICANCE STATEMENT Axon degeneration resulting from trauma or neurodegenerative disease can cause devastating deficits in neural function. Understanding the molecular and cellular events that execute axon degeneration is essential for developing treatments to address these conditions. Calcium is known to contribute to axon degeneration, but its temporal requirements in this process have been unclear. Live calcium imaging in severed zebrafish neurons and temporally controlled

  15. Calcium isotope fractionation between soft and mineralized tissues as a monitor of calcium use in vertebrates (United States)

    Skulan, Joseph; DePaolo, Donald J.


    Calcium from bone and shell is isotopically lighter than calcium of soft tissue from the same organism and isotopically lighter than source (dietary) calcium. When measured as the 44Ca/40Ca isotopic ratio, the total range of variation observed is 5.5‰, and as much as 4‰ variation is found in a single organism. The observed intraorganismal calcium isotopic variations and the isotopic differences between tissues and diet indicate that isotopic fractionation occurs mainly as a result of mineralization. Soft tissue calcium becomes heavier or lighter than source calcium during periods when there is net gain or loss of mineral mass, respectively. These results suggest that variations of natural calcium isotope ratios in tissues may be useful for assessing the calcium and mineral balance of organisms without introducing isotopic tracers. PMID:10570137

  16. Building better bones in childhood: a randomized controlled study to test the efficacy of a dietary intervention program to increase calcium intake. (United States)

    Weber, D R; Stark, L J; Ittenbach, R F; Stallings, V A; Zemel, B S


    Many children do not consume the recommended daily allowance of calcium. Inadequate calcium intake in childhood may limit bone accrual. The objective of this study was to determine if a behavioral modification and nutritional education (BM-NE) intervention improved dietary calcium intake and bone accrual in children. 139 (86 female) healthy children, 7-10 years of age, were enrolled in this randomized controlled trial conducted over 36 months. Participants randomized to the BM-NE intervention attended five sessions over a 6-week period designed to increase calcium intake to 1500 mg/day. Participants randomized to the usual care (UC) group received a single nutritional counseling session. The Calcium Counts Food Frequency Questionnaire was used to assess calcium intake; dual energy X-ray absorptiometry was used to assess areal bone mineral density (aBMD) and bone mineral content (BMC). Longitudinal mixed effects models were used to assess for an effect of the intervention on calcium intake, BMC and aBMD. BM-NE participants had greater increases in calcium intake that persisted for 12 months following the intervention compared with UC. The intervention had no effect on BMC or aBMD accrual. Secondary analyses found a negative association between calcium intake and adiposity such that greater calcium intake was associated with lesser gains in body mass index and fat mass index. A family-centered BM-NE intervention program in healthy children was successful in increasing calcium intake for up to 12 months but had no effect on bone accrual. A beneficial relationship between calcium intake and adiposity was observed and warrants future study.

  17. Cardiovascular Effects of Calcium Supplements

    Directory of Open Access Journals (Sweden)

    Ian R. Reid


    Full Text Available Calcium supplements reduce bone turnover and slow the rate of bone loss. However, few studies have demonstrated reduced fracture incidence with calcium supplements, and meta-analyses show only a 10% decrease in fractures, which is of borderline statistical and clinical significance. Trials in normal older women and in patients with renal impairment suggest that calcium supplements increase the risk of cardiovascular disease. To further assess their safety, we recently conducted a meta-analysis of trials of calcium supplements, and found a 27%–31% increase in risk of myocardial infarction, and a 12%–20% increase in risk of stroke. These findings are robust because they are based on pre-specified analyses of randomized, placebo-controlled trials and are consistent across the trials. Co-administration of vitamin D with calcium does not lessen these adverse effects. The increased cardiovascular risk with calcium supplements is consistent with epidemiological data relating higher circulating calcium concentrations to cardiovascular disease in normal populations. There are several possible pathophysiological mechanisms for these effects, including effects on vascular calcification, vascular cells, blood coagulation and calcium-sensing receptors. Thus, the non-skeletal risks of calcium supplements appear to outweigh any skeletal benefits, and are they appear to be unnecessary for the efficacy of other osteoporosis treatments.

  18. Dietary Calcium Intake and Calcium Supplementation in Hungarian Patients with Osteoporosis

    Directory of Open Access Journals (Sweden)

    Gábor Speer


    Full Text Available Purpose. Adequate calcium intake is the basis of osteoporosis therapy—when this proves insufficient, even specific antiosteoporotic agents cannot exert their actions properly. Methods. Our representative survey analyzed the dietary intake and supplementation of calcium in 8033 Hungarian female and male (mean age: 68 years (68.01 (CI95: 67.81–68.21 patients with osteoporosis. Results. Mean intake from dietary sources was 665±7.9 mg (68.01 (CI95: 67.81–68.21 daily. A significant positive relationship could be detected between total dietary calcium intake and lumbar spine BMD (P=0.045, whereas such correlation could not be demonstrated with femoral T-score. Milk consumption positively correlated with femur (P=0.041, but not with lumbar BMD. The ingestion of one liter of milk daily increased the T-score by 0.133. Average intake from supplementation was 558±6.2 mg (68.01 (CI95: 67.81–68.21 daily. The cumulative dose of calcium—from both dietary intake and supplementation—was significantly associated with lumbar (r=0.024, P=0.049, but not with femur BMD (r=0.021, P=0.107. The currently recommended 1000–1500 mg total daily calcium intake was achieved in 34.5% of patients only. It was lower than recommended in 47.8% of the cases and substantially higher in 17.7% of subjects. Conclusions. We conclude that calcium intake in Hungarian osteoporotic patients is much lower than the current recommendation, while routinely applied calcium supplementation will result in inappropriately high calcium intake in numerous patients.

  19. Calcium oxalate stone and gout. (United States)

    Marickar, Y M Fazil


    Gout is well known to be produced by increased uric acid level in blood. The objective of this paper is to assess the relationship between gout and calcium oxalate stone formation in the humans. 48 patients with combination of gout and calcium oxalate stone problem were included. The biochemical values of this group were compared with 38 randomly selected uric acid stone patients with gout, 43 stone patients with gout alone, 100 calcium oxalate stone patients without gout and 30 controls, making a total of 259 patients. Various biochemical parameters, namely serum calcium, phosphorus and uric acid and 24-h urine calcium, phosphorus, uric acid, oxalate, citrate and magnesium were analysed. ANOVA and Duncan's multiple-range tests were performed to assess statistical significance of the variations. The promoters of stone formation, namely serum calcium (P stone patients and gouty calcium oxalate stone patients compared to the non-gouty patients and controls. Urine oxalate (P stones patients. The inhibitor urine citrate (P stone gouty patients, followed by the gouty uric acid stone formers and gouty calcium oxalate stone patients. The high values of promoters, namely uric acid and calcium in the gouty stone patients indicate the tendency for urinary stone formation in the gouty stone patients. There is probably a correlation between gout and calcium oxalate urinary stone. We presume this mechanism is achieved through the uric acid metabolism. The findings point to the summation effect of metabolic changes in development of stone disease.

  20. Purification and reconstitution of the calcium antagonist receptor of the voltage-sensitive calcium channel

    International Nuclear Information System (INIS)

    Curtis, B.M.


    Treatment with digitonin solubilized the calcium antagonist receptor as a stable complex with [ 3 H]nitrendipine from rat brain membranes. The solubilized complex retains allosteric coupling to binding sites for diltiazem, verapamil, and inorganic calcium antagonist sites. The calcium antagonist receptor from cardiac sarcolemma and the transverse-tubule membrane of skeletal muscle is also efficiently solubilized with digitonin and the receptor in all three tissues is a large glycoprotein with a sedimentation coefficient of 20 S. The T-tubule calcium antagonist receptor complex was extensively purified by a combination of chromatography on WGA-Sepharose, ion exchange chromatography, and sedimentation on sucrose gradients to yield preparations estimated to be 41% homogeneous by specific activity and 63% homogeneous by SDS gel electrophoresis. Analysis of SDS gels detect three polypeptides termed α(Mr 135,000), β(Mr 50,000), and γ(Mr 32,000) as noncovalently associated subunits of the calcium antagonist receptor. The α and γ subunits are glycosylated polypeptides, and the molecular weight of the core polypeptides are 108,000 and 24,000 respectively. The calcium antagonist receptor was reconstituted into a phospholipid bilayer by adding CHAPS and exogeneous lipid to the purified receptor followed by rapid detergent removal. This procedure resulted in the incorporation of 45% of the calcium antagonist receptor into closed phospholipid vesicles. Data suggests that the α, β, and γ subunits of the T-tubule calcium antagonist receptor are sufficient to form a functional calcium channel

  1. Why Calcium? How Calcium Became the Best Communicator*


    Carafoli, Ernesto; Krebs, Joachim


    Calcium carries messages to virtually all important functions of cells. Although it was already active in unicellular organisms, its role became universally important after the transition to multicellular life. In this Minireview, we explore how calcium ended up in this privileged position. Most likely its unique coordination chemistry was a decisive factor as it makes its binding by complex molecules particularly easy even in the presence of large excesses of other cations,...

  2. Calcium-Induced calcium release during action potential firing in developing inner hair cells. (United States)

    Iosub, Radu; Avitabile, Daniele; Grant, Lisa; Tsaneva-Atanasova, Krasimira; Kennedy, Helen J


    In the mature auditory system, inner hair cells (IHCs) convert sound-induced vibrations into electrical signals that are relayed to the central nervous system via auditory afferents. Before the cochlea can respond to normal sound levels, developing IHCs fire calcium-based action potentials that disappear close to the onset of hearing. Action potential firing triggers transmitter release from the immature IHC that in turn generates experience-independent firing in auditory neurons. These early signaling events are thought to be essential for the organization and development of the auditory system and hair cells. A critical component of the action potential is the rise in intracellular calcium that activates both small conductance potassium channels essential during membrane repolarization, and triggers transmitter release from the cell. Whether this calcium signal is generated by calcium influx or requires calcium-induced calcium release (CICR) is not yet known. IHCs can generate CICR, but to date its physiological role has remained unclear. Here, we used high and low concentrations of ryanodine to block or enhance CICR to determine whether calcium release from intracellular stores affected action potential waveform, interspike interval, or changes in membrane capacitance during development of mouse IHCs. Blocking CICR resulted in mixed action potential waveforms with both brief and prolonged oscillations in membrane potential and intracellular calcium. This mixed behavior is captured well by our mathematical model of IHC electrical activity. We perform two-parameter bifurcation analysis of the model that predicts the dependence of IHCs firing patterns on the level of activation of two parameters, the SK2 channels activation and CICR rate. Our data show that CICR forms an important component of the calcium signal that shapes action potentials and regulates firing patterns, but is not involved directly in triggering exocytosis. These data provide important insights

  3. 21 CFR 573.260 - Calcium silicate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 573.260 Section 573.260 Food and... Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used as an anticaking agent in animal feed, provided that the amount of calcium silicate does not...

  4. 21 CFR 573.240 - Calcium periodate. (United States)


    ... with calcium hydroxide or calcium oxide to form a substance consisting of not less than 60 percent by... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium periodate. 573.240 Section 573.240 Food... Additive Listing § 573.240 Calcium periodate. The food additive calcium periodate may be safely used in...

  5. Calcium chromate process related investigations

    International Nuclear Information System (INIS)

    Dillard, B.M.


    A pilot plant for production of calcium chromate has been scaled up to a small production facility at the General Electric Neutron Devices Department. In preparation for this scale-up, the process and final product were studied in order to evaluate problems not considered previously. The variables and processes studied included: (1) the determination of optimum drying temperature and time for product analysis; (2) the effect of the grade of lime used as the precipitating agent on the purity of the calcium chromate; (3) product purity when calcium chromate is precipitated by the addition of ammonium chromate to slaked lime; (4) the reagents best suited for cleaning calcium chromate spills; and (5) methods for determining hydroxide ion concentration in calcium chromate. The optimum drying time for the product before analysis is four hours at 600 0 C. Gases evolved at various temperatures during the drying process were carbon dioxide and water vapor. Technical grade lime produced calcium chromate of the highest purity. Both nitric and acetic acids were efficient dissolvers of calcium chromate spills. Direct titration of hydroxide ion with sulfuric acid gave an average recovery of 93% for samples spiked with calcium hydroxide. 1 figure, 17 tables

  6. [The fasting calcium/creatinine ratio in patients with calcium stones and the relation with hypercalciuria and phosphocalcium metabolism]. (United States)

    Arrabal-Polo, Miguel Ángel; del Carmen Cano-García, María; Arrabal-Martín, Miguel


    To determine the importance of fasting calcium/creatinine ratio in patients with calcium stones and its relation with hypercalciuria and phospho-calcium metabolism. Cross-sectional study including 143 patients divided into two groups according to fasting calcium/creatinine. Group 1: 66 patients (calcium/ creatininecreatinine>0.11). A comparative study is performed between groups including phospho-calcium metabolism parameters and excretion of urinary lithogenic markers. Linear correlation studying calciuria and fasting calcium/ creatinine was performed. SPSS 17.0 statistical analysis software was used, considering p≤0.05. It is noteworthy that group 2 had increased 24 h urine calcium excretion in comparison to group 1 (229.3 vs 158.1; p=0.0001) and calcium/citrate (0.47 vs 0.34; p=0.001). There is a positive and significant correlation between calcium levels in 24 h urine and fasting calcium/creatinine (R=0.455; p=0.0001) and a cutoff is set at 0.127 (sensitivity 72%, specificity 66%) to determine hypercalciuria (>260 mg in 24 h). Increased fasting calcium/creatinine determines increased 24 hours calcium excretion, although the sensitivity and specificity to determine hypercalciuria is not high.

  7. The relation between calcium intake and body composition in a Dutch population: the Amsterdam Growth and Health Longitudinal Study

    NARCIS (Netherlands)

    Boon, N.; Koppes, L.L.J.; Saris, W.H.; van Mechelen, W.


    To investigate whether dietary calcium intake is related to body mass index and the sum of four skinfolds among subjects in the Amsterdam Growth and Health Longitudinal Study (the Netherlands), the authors followed a cohort of men and women from age 13 years in 1977 to age 36 years in 2000.

  8. Calcium regulation and Alzheimer’s disease

    Directory of Open Access Journals (Sweden)

    Deepthi Rapaka


    Full Text Available Activation of the neuron induces transient fluctuations in [Ca2+]i. This transient rise in [Ca2+]i is dependent on calcium entry via calcium channels and release of calcium from intracellular stores, finally resulting in increase in calcium levels, which activates calcium regulatory proteins to restore the resting calcium levels by binding to the calcium-binding proteins, sequestration into the endoplasmic reticulum and the mitochondria, and finally extrusion of calcium spike potential from the cell by adenosine triphosphate-driven Ca2+ pumps and the Na+/Ca2+ exchanger. Improper regulation of calcium signaling, sequentially, likely contributes to synaptic dysfunction and excitotoxic and/or apoptotic death of the vulnerable neuronal populations. The cognitive decline associated with normal aging is not only due to neuronal loss, but is fairly the result of synaptic connectivity. Many evidences support that Ca2+ dyshomeostasis is implicated in normal brain aging. Thus the chief factor associated with Alzheimer’s disease was found to be increase in the levels of free intracellular calcium, demonstrating that the excessive levels might lead to cell death, which provides a key target for the calcium channel blockers might be used as the neuroprotective agents in Alzheimer’s disease.

  9. 21 CFR 184.1207 - Calcium lactate. (United States)


    ... 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 Chemicals...

  10. Calcium Occupancy of N-terminal Sites within Calmodulin Induces Inhibition of the Ryanodine Receptor Calcium Release Channel

    Energy Technology Data Exchange (ETDEWEB)

    Boschek, Curt B; Jones, Terry E; Squier, Thomas C; Bigelow, Diana J


    Calmodulin (CaM) regulates calcium release from intracellular stores in skeletal muscle through its association with the ryanodine receptor (RyR1) calcium release channel, where CaM association enhances channel opening at resting calcium levels and its closing at micromolar calcium levels associated with muscle contraction. A high-affinity CaM-binding sequence (RyRp) has been identified in RyR1, which corresponds to a 30-residue sequence (i.e., K3614 – N3643) located within the central portion of the primary sequence. However, it is currently unclear whether the identified CaM-binding sequence a) senses calcium over the physiological range of calcium-concentrations associated with RyR1 regulation or b) plays a structural role unrelated to the calcium-dependent modulation of RyR1 function. Therefore, we have measured the calcium-dependent activation of the individual domains of CaM in association with RyRp and their relationship to the CaM-dependent regulation of RyR1. These measurements utilize an engineered CaM, permitting the site-specific incorporation of N-(1-pyrene) maleimide at either T34C (PyN-CaM) or T110C (PyC-CaM) in the N- and C-domains, respectively. Consistent with prior measurements, we observe a high-affinity association between both apo- and calcium-activated CaM and RyRp. Upon association with RyRp, fluorescence changes in PyN-CaM or PyC-CaM permit the measurement of the calcium-activation of these individual domains. Fluorescence changes upon calcium-activation of PyC-CaM in association with RyRp are indicative of high-affinity calcium-dependent activation of the C-terminal domain of CaM bound to RyRp at resting calcium levels and the activation of the N-terminal domain at levels of calcium associated cellular activation. In comparison, occupancy of calcium-binding sites in the N-domain of CaM mirrors the calcium-dependence of RyR1 inhibition observed at activating calcium levels, where [Ca]1/2 = 4.3 0.4 μM, suggesting a direct regulation of Ry

  11. Acidosis and Urinary Calcium Excretion

    DEFF Research Database (Denmark)

    Alexander, R Todd; Cordat, Emmanuelle; Chambrey, Régine


    Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary calcium excretion induced by metabolic acidosis predominantly results from increased mobilization of calcium out of bone and inhibi...

  12. Calcium microdomains near R-type calcium channels control the induction of presynaptic LTP at parallel fiber to Purkinje cell synapses (United States)

    Myoga, Michael H.; Regehr, Wade G.


    R-type calcium channels in postsynaptic spines signal through functional calcium microdomains to regulate a calcium-calmodulin sensitive potassium channel that in turn regulates postsynaptic hippocampal LTP. Here we ask whether R-type calcium channels in presynaptic terminals also signal through calcium microdomains to control presynaptic LTP. We focus on presynaptic LTP at parallel fiber to Purkinje cell synapses in the cerebellum (PF-LTP), which is mediated by calcium/calmodulin-stimulated adenylyl cyclases. Although most presynaptic calcium influx is through N-type and P/Q-type calcium channels, blocking these channels does not disrupt PF-LTP, but blocking R-type calcium channels does. Moreover, global calcium signaling cannot account for the calcium dependence of PF-LTP because R-type channels contribute modestly to overall calcium entry. These findings indicate that within presynaptic terminals, R-type calcium channels produce calcium microdomains that evoke presynaptic LTP at moderate frequencies that do not greatly increase global calcium levels,. PMID:21471358

  13. The role of calcium utilization of intestinal flora on urinary calcium excretion

    International Nuclear Information System (INIS)

    Yurt Lambrecht, F.; Uenak, P.; Kavukcu, S.; Soylu, A.; Tuerkmen, M.; Kasap, B.; Yucesoy, M.; Esen, N.


    Aim: To investigate whether calcium utilization of intestinal flora has any effect on urinary calcium excretion, like oxalate degrading effect of Oxalobacter formigenes. Materials and Methods: The data of urinary calcium excretion examinations were evaluated. 0.1 g/ml of feces samples were implanted in broths. 5 μL of 45 Ca solution was added to the samples and they were incubated for 24 hours at 37 degree C. The amount of bacteriae in the samples was determined as colony forming unit (CFU). 200 μL of the samples were filtrated by 0.45 μm membrane and rinsed by 200 μL pure water. 45 Ca activity ( 45 Ca) of bacteria in the membrane was counted by GM detector for 100 seconds. Then, activity per CFU ( 45 Ca/CFU) was calculated and compared in hypercalciuric (calciuria >4; mg/kg/hour and/or calcium/creatinine ratio>0.21; Group I) and normocalciuric (Group II) patients. Results: Samples of 29 patients with a mean age of 7.50±4.28 (1.5-16) years were evaluated. 11 of them were female (M/F: 18/11). There were 14 patients in Group I and 15 patients in Group II, 45 Ca/CFU was not different for neither aerobic nor anaerobic bacteries between the two groups (p:0.983, p:0.601, respectively). 24-hour urine calcium levels were negatively but not significantly correlated to aerobic and anaerobic 45 Ca/CFU (p:0.079, r:-0.145; p:0.260, r:-0.420, respectively) in hypercalciuric patients. Besides, in normocalciuric patients, 24-hour urine calcium levels were correlated positively to aerobic and negatively to anaerobic 45 Ca/CFU again in an insignificant manner (p:0.509, r: 0.223; p:0623, r:-0.257, respectively). Conclusion: In this, study, similar 45 Ca/CFU levels in both hypercalciuric and normocalciuric patients imply that calcium utilization of intestinal flora does not have a distinct effect on urinary calcium excretion but, although not significant, there was a negative correlation between urine calcium levels and bacterial 45 Ca/CFU levels especially in hypercalciuric

  14. 36 CFR 1002.36 - Gambling. (United States)


    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Gambling. 1002.36 Section 1002.36 Parks, Forests, and Public Property PRESIDIO TRUST RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 1002.36 Gambling. (a) Gambling in any form, or the operation of gambling devices, is prohibited...

  15. High Dose Oral Calcium Treatment in Patients with Vitamin D-dependent Rickets Type II

    Directory of Open Access Journals (Sweden)

    R Vakili


    Full Text Available BACKGROUND AND OBJECTIVE: Vitamin D-dependent rickets type II (VDDR2 is a rare genetic disorder caused by mutations in vitamin D receptor (VDR and leads to resistance to biological effects of calcitriol. Based on the type of mutation, this disease is resistant to calcitriol even at high doses of calcitriol and successful treatment of these patients requires hypocalcemic modification through administration of high doses of calcium and bypassing the intestinal defect in VDR signaling. In addition to the need for frequent hospitalization and high costs, intravenous administration of calcium is associated with complications and problems such as arrhythmia and sepsis, venous catheter infection and hypercalciuria. This study aims to report the positive treatment effects of high doses of oral calcium in 4 patients with vitamin D-dependent rickets type II. CASE REPORT: In this study, 4 patients with vitamin D-dependent rickets type II, diagnosed based on clinical and biochemical symptoms of rickets with alopecia, underwent therapy using high doses of oral calcium (300 mg/kg/day in pediatric endocrinology and metabolism center of Imam Reza hospital. After a short period, increased growth rate in height, strength and elasticity of muscles was observed in addition to biochemical improvements without serious side effects and even one patient started walking independently within the first week of therapy for the first time. Patients were regularly followed up in terms of height and weight, growth rate and biochemical factors including calcium, phosphorus and alkaline phosphatase every 3 months for one year. CONCLUSION: Regardless of the type of mutation in vitamin D receptor, it is suggested that a 3-6 months trial of high dose oral calcium be started in each patient with vitamin D-dependent rickets type II, particularly for patients whose disease was diagnosed at lower ages.

  16. 36 CFR 2.36 - Gambling. (United States)


    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Gambling. 2.36 Section 2.36 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.36 Gambling. (a) Gambling in any form, or the operation of gambling...

  17. Movement of calcium signals and calcium-binding proteins: firewalls, traps and tunnels. (United States)

    Barrow, S L; Sherwood, M W; Dolman, N J; Gerasimenko, O V; Voronina, S G; Tepikin, A V


    In the board game 'Snakes and Ladders', placed on the image of a pancreatic acinar cell, calcium ions have to move from release sites in the secretory region to the nucleus. There is another important contraflow - from calcium entry channels in the basal part of the cell to ER (endoplasmic reticulum) terminals in the secretory granule region. Both transport routes are perilous as the messenger can disappear in any place on the game board. It can be grabbed by calcium ATPases of the ER (masquerading as a snake but functioning like a ladder) and tunnelled through its low buffering environment, it can be lured into the whirlpools of mitochondria uniporters and forced to regulate the tricarboxylic acid cycle, and it can be permanently placed inside the matrix of secretory granules and released only outside the cell. The organelles could trade calcium (e.g. from the ER to mitochondria and vice versa) almost depriving this ion the light of the cytosol and noble company of cytosolic calcium buffers. Altogether it is a rich and colourful story.

  18. Calcium binding properties of calcium dependent protein kinase 1 (CaCDPK1) from Cicer arietinum. (United States)

    Dixit, Ajay Kumar; Jayabaskaran, Chelliah


    Calcium plays a crucial role as a secondary messenger in all aspects of plant growth, development and survival. Calcium dependent protein kinases (CDPKs) are the major calcium decoders, which couple the changes in calcium level to an appropriate physiological response. The mechanism by which calcium regulates CDPK protein is not well understood. In this study, we investigated the interactions of Ca(2+) ions with the CDPK1 isoform of Cicer arietinum (CaCDPK1) using a combination of biophysical tools. CaCDPK1 has four different EF hands as predicted by protein sequence analysis. The fluorescence emission spectrum of CaCDPK1 showed quenching with a 5 nm red shift upon addition of calcium, indicating conformational changes in the tertiary structure. The plot of changes in intensity against calcium concentrations showed a biphasic curve with binding constants of 1.29 μM and 120 μM indicating two kinds of binding sites. Isothermal calorimetric (ITC) titration with CaCl2 also showed a biphasic curve with two binding constants of 0.027 μM and 1.7 μM. Circular dichroism (CD) spectra showed two prominent peaks at 208 and 222 nm indicating that CaCDPK1 is a α-helical rich protein. Calcium binding further increased the α-helical content of CaCDPK1 from 75 to 81%. Addition of calcium to CaCDPK1 also increased fluorescence of 8-anilinonaphthalene-1-sulfonic acid (ANS) indicating exposure of hydrophobic surfaces. Thus, on the whole this study provides evidence for calcium induced conformational changes, exposure of hydrophobic surfaces and heterogeneity of EF hands in CaCDPK1. Copyright © 2015 Elsevier GmbH. All rights reserved.

  19. Calcium transport in turtle bladder

    International Nuclear Information System (INIS)

    Sabatini, S.; Kurtzman, N.A.


    Unidirectional 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 net Ca ) was secretory (serosa to mucosa). Ouabain reversed J net Ca to an absorptive flux. Amiloride reduced both fluxes such that J net 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 net Ca decreased to approximately one-third of control value but remained secretory. When ouabain was added under short-circuit conditions, J net Ca was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue 45 Ca content was ≅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 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 + -K + -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

  20. Calcium in Urine Test (United States)

    ... K. Brunner & Suddarth's Handbook of Laboratory and Diagnostic Tests. 2 nd Ed, Kindle. Philadelphia: Wolters Kluwer Health, Lippincott Williams & Wilkins; c2014. Calcium, Serum; Calcium and Phosphates, Urine; ...

  1. Effects of extracellular calcium on calcium transport during hyperthermia of tumor cells. (United States)

    Anghileri, L J; Marcha, C; Crone-Escanyé, M C; Robert, J


    The effects of different concentrations of extracellular ion calcium on the transport of calcium by tumor cells have been studied by means of the uptake of radiocalcium. Tumor cells incubated at 45 degrees C take up 4-10 times the amount of radioactivity incorporated by cells incubated at 37 degrees C. The difference is still greater (up to 100 times) for the intracellular incorporation as assessed by elimination of the membrane-bound calcium by EGTA treatment. The possible mechanisms involved in this differential behavior are discussed.

  2. Determination of "2"1"0Po in calcium supplements and the possible related dose assessment to the consumers

    International Nuclear Information System (INIS)

    Strumińska-Parulska, Dagmara I.


    The aim of this pioneer study was to investigate the most popular calcium supplements as a potential additional source of polonium "2"1"0Po in human diet. The analyzed calcium pharmaceutics contained organic or inorganic calcium compounds; some from natural sources as mussels' shells, fish extracts, or sedimentary rocks. The objectives of this research were to investigate the naturally occurring "2"1"0Po activity concentrations in calcium supplements, find the correlations between "2"1"0Po concentration in medicament and calcium chemical form, and calculate the effective radiation dose connected to analyzed calcium supplement consumption. As results showed, "2"1"0Po concentrations in natural origin calcium supplements (especially sedimentary rocks) were higher than the other analyzed. Also the results of "2"1"0Po analysis obtained for inorganic forms of calcium supplements were higher. The highest "2"1"0Po activity concentrations were determined in mineral tablets made from sedimentary rocks: dolomite and chalk – 3.88 ± 0.22 and 3.36 ± 0.10 mBq g"−"1 respectively; while the lowest in organic calcium compounds: calcium lactate and calcium gluconate – 0.07 ± 0.02 and 0.17 ± 0.01 mBq g"−"1. The annual effective radiation doses from supplements intake were estimated as well. The highest annual radiation dose from "2"1"0Po taken with 1 tablet of calcium supplement per day was connected to sample made from chalk – 2.5 ± 0.07 μSv year"−"1, while the highest annual radiation dose from "2"1"0Po taken with 1 g of pure calcium per day was connected to dolomite – 12.7 ± 0.70 μSv year"−"1. - Highlights: • "2"1"0Po in the most popular calcium supplements in Poland was investigated. • "2"1"0Po is present in calcium supplements and could be an additional source of "2"1"0Po for human. • Inorganic samples were richer in "2"1"0Po in comparison to organic. • Additives from sedimentary rocks, were richer in polonium in comparison to

  3. 21 CFR 172.410 - Calcium silicate. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true 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 safely...

  4. Relative biological activity of amorphous calcium and calcium-magnesium phosphates

    International Nuclear Information System (INIS)

    Silina, E.N.; Kunitsa, T.N.; Shuslikova, E.S.; Griggs, J.; Levchenko, L.V.; Karjaubaeva, R.A.; Sinyayev, V.A.


    Three amorphous calcium and calcium-magnesium phosphates that are close on composition to mineral basis of the bone tissues are compared on bioactivity in the given article. Properties of the hydrated substances produced from water solutions and their derivations, which are formed due to thermal treatment, are discussed here. As a detector of bioactivity was used microbial culture E-Coli. [author

  5. The effects of excess calcium on the handling and mechanical properties of hydrothermal derived calcium phosphate bone cement (United States)

    Razali, N. N.; Sukardi, M. A.; Sopyan, I.; Mel, M.; Salleh, H. M.; Rahman, M. M.


    The objective of this study is to determine the effects of excess calcium on the handling and mechanical properties of hydrothermal derived calcium phosphate cement (CPC) for bone filling applications. Hydroxyapatite powder was synthesized via hydrothermal method using calcium oxide, CaO and ammonium dihydrogen phosphate, NH4H2PO4 as the calcium and phosphorus precursors respectively. The effects of calcium excess were evaluated by varying the CaO content at 0, 5 and 15 mole %. The precursors were then refluxed in distilled water at 90-100°C and dried overnight until the calcium phosphate powder was formed. CPC was then produced by mixing the synthesized powder with distilled water at the powder-to-liquid (P/L) ratio of 1.5. The result from the morphological properties of CPC shows the increase in agglomeration and particles size with 5 mole % of calcium excess but decreased with 15 mole % of calcium excess in CPC. This result was in agreement with the compressive strength result where the CPC increased its strength with 5 mole % of calcium excess but reduced with 15 mole % of calcium excess. The excess in calcium precursor also significantly improved the setting time but reduced the injectability of CPC.

  6. Association of calcium sensing receptor polymorphisms at rs1801725 with circulating calcium in breast cancer patients. (United States)

    Wang, Li; Widatalla, Sarrah E; Whalen, Diva S; Ochieng, Josiah; Sakwe, Amos M


    Breast cancer (BC) patients with late-stage and/or rapidly growing tumors are prone to develop high serum calcium levels which have been shown to be associated with larger and aggressive breast tumors in post and premenopausal women respectively. Given the pivotal role of the calcium sensing receptor (CaSR) in calcium homeostasis, we evaluated whether polymorphisms of the CASR gene at rs1801725 and rs1801726 SNPs in exon 7, are associated with circulating calcium levels in African American and Caucasian control subjects and BC cases. In this retrospective case-control study, we assessed the mean circulating calcium levels, the distribution of two inactivating CaSR SNPs at rs1801725 and rs1801726 in 199 cases and 384 age-matched controls, and used multivariable regression analysis to determine whether these SNPs are associated with circulating calcium in control subjects and BC cases. We found that the mean circulating calcium levels in African American subjects were higher than those in Caucasian subjects (p calcium levels were higher in BC cases compared to control subjects (p calcium levels in BC patients were independent of race. We also show that in BC cases and control subjects, the major alleles at rs1801725 (G/T, A986S) and at rs1801726 (C/G, Q1011E) were common among Caucasians and African Americans respectively. Compared to the wild type alleles, polymorphisms at the rs1801725 SNP were associated with higher calcium levels (p = 0.006) while those at rs1801726 were not. Using multivariable linear mixed-effects models and adjusting for age and race, we show that circulating calcium levels in BC cases were associated with tumor grade (p = 0.009), clinical stage (p = 0.003) and more importantly, with inactivating mutations of the CASR at the rs1801725 SNP (p = 0.038). These data suggest that decreased sensitivity of the CaSR to calcium due to inactivating polymorphisms at rs1801725, may predispose up to 20% of BC cases to high circulating calcium

  7. Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

    International Nuclear Information System (INIS)

    Christensen, Hilbert


    By means of homogeneous precipitation it has been possible to synthesize crystalline solid solutions of calcium strontium hydroxyapatite from aqueous solutions. The lattice constants for the solid solutions were measured in the range Ca 9 Sr(PO 4 ) 6 (OH) 2 - CaSr 9 (PO 4 ) 6 (OH) 2 . The investigations show that the discrimination of strontium against calcium is considerably smaller than reported elsewhere (1). Strontium is preferentially built into the c-axis direction of the apatite lattice

  8. Isolation and identification of calcium-chelating peptides from Pacific cod skin gelatin and their binding properties with calcium. (United States)

    Wu, Wenfei; Li, Bafang; Hou, Hu; Zhang, Hongwei; Zhao, Xue


    A calcium-chelating peptide is considered to have the ability to improve calcium absorption. In this study, Pacific cod skin gelatin hydrolysates treated with trypsin for 120 min exhibited higher calcium-chelating activity. Sequential chromatography, involving hydroxyapatite affinity chromatography and reversed phase high performance liquid chromatography, was used for the purification of calcium-chelating peptides. Two novel peptides with the typical characteristics of collagen were sequenced as GDKGESGEAGER and GEKGEGGHR based on LC-HRMS/MS, which showed a high affinity to calcium. Calcium-peptide complexation was further characterized by ESI-MS (MS and MS/MS) and FTIR spectroscopy. The results showed that the complexation of the two peptides with calcium was conducted mainly at the ratio of 1 : 1. The amino terminal group and the peptide bond of the peptide backbone as well as the amino group of the lysine side chain and the carboxylate of the glutamate side chain were the possible calcium binding sites for the two peptides. Meanwhile, several amino acid side chain groups, including the hydroxyl (Ser) and carboxylate (Asp) of GDKGESGEAGER and the imine (His) of GEKGEGGHR, were crucial in the complexation. The arginine residue in GEKGEGGHR also participated in the calcium coordination. Additionally, several active fragments with calcium-chelating activity were obtained using MS/MS spectra, including GDKGESGEAGE, GEAGER, GEK, EKG and KGE. This study suggests that gelatin-derived peptides have the potential to be used as a calcium-chelating ingredient to combat calcium deficiency.

  9. Dietary calcium but not elemental calcium from supplements is associated with body composition and obesity in Chinese women.

    Directory of Open Access Journals (Sweden)

    Lina Huang

    Full Text Available We assessed whether dietary calcium intake or calcium supplements associated with body composition and obesity in a Chinese population.A cross-sectional survey was performed in a population of 8940, aged 20 to 74 y. 8127 participants responded (90.9%. Height, weight, fat mass (FM, waist circumference (WC and hip circumference were measured. Obesity definition: body mass index (BMI ≥28 kg/m(2 (overall obesity; WC ≥85 cm for men or ≥80 cm for women (abdominal obesity І and waist hip ratio (WHR ≥0.90 for men or ≥0.85 for women (abdominal obesity П. The data on dietary calcium and calcium supplements were collected using food-frequency questionnaire and self-report questionnaire. Multivariate linear and multivariable logistic regressions were used to examine the associations between dietary calcium intake or calcium supplements and body composition and obesity.The average dietary calcium intake of all subjects was 430 mg/d. After adjusting for potential confounding factors, among women only, negative associations were observed between habitual dietary calcium intake and four measures of body composition (β, -0.086, P0.05. Similarly, among both men and women, we did not observe significant associations between calcium supplements and any measures of body composition or abdominal obesity (P>0.05.Dietary calcium from food rather than elemental calcium from calcium supplements has beneficial effects on the maintenance of body composition and preventing abdominal obesity in Chinese women.

  10. Exopolysaccharides regulate calcium flow in cariogenic biofilms (United States)

    Varenganayil, Muth M.; Decho, Alan W.


    Caries-associated biofilms induce loss of calcium from tooth surfaces in the presence of dietary carbohydrates. Exopolysaccharides (EPS) provide a matrix scaffold and an abundance of primary binding sites within biofilms. The role of EPS in binding calcium in cariogenic biofilms is only partially understood. Thus, the aim of the present study is to investigate the relationship between the calcium dissolution rates and calcium tolerance of caries-associated bacteria and yeast as well as to examine the properties of EPS to quantify its binding affinity for dissolved calcium. Calcium dissolution was measured by dissolution zones on Pikovskaya’s agar. Calcium tolerance was assessed by isothermal microcalorimetry (IMC) by adding CaCl2 to the bacterial cultures. Acid-base titration and Fourier transform infrared (FTIR) spectroscopy were used to identify possible functional groups responsible for calcium binding, which was assessed by isothermal titration calorimetry (ITC). Lactobacillus spp. and mutans streptococci demonstrated calcium dissolution in the presence of different carbohydrates. All strains that demonstrated high dissolution rates also revealed higher rates of calcium tolerance by IMC. In addition, acidic functional groups were predominantly identified as possible binding sites for calcium ions by acid-base titration and FTIR. Finally, ITC revealed EPS to have a higher binding affinity for calcium compared, for example, to lactic acid. In conclusion, this study illustrates the role of EPS in terms of the calcium tolerance of cariogenic microbiota by determining the ability of EPS to control free calcium concentrations within the biofilms as a self-regulating mode of action in the pathogenesis of dental caries. PMID:29023506

  11. Exopolysaccharides regulate calcium flow in cariogenic biofilms.

    Directory of Open Access Journals (Sweden)

    Monika Astasov-Frauenhoffer

    Full Text Available Caries-associated biofilms induce loss of calcium from tooth surfaces in the presence of dietary carbohydrates. Exopolysaccharides (EPS provide a matrix scaffold and an abundance of primary binding sites within biofilms. The role of EPS in binding calcium in cariogenic biofilms is only partially understood. Thus, the aim of the present study is to investigate the relationship between the calcium dissolution rates and calcium tolerance of caries-associated bacteria and yeast as well as to examine the properties of EPS to quantify its binding affinity for dissolved calcium. Calcium dissolution was measured by dissolution zones on Pikovskaya's agar. Calcium tolerance was assessed by isothermal microcalorimetry (IMC by adding CaCl2 to the bacterial cultures. Acid-base titration and Fourier transform infrared (FTIR spectroscopy were used to identify possible functional groups responsible for calcium binding, which was assessed by isothermal titration calorimetry (ITC. Lactobacillus spp. and mutans streptococci demonstrated calcium dissolution in the presence of different carbohydrates. All strains that demonstrated high dissolution rates also revealed higher rates of calcium tolerance by IMC. In addition, acidic functional groups were predominantly identified as possible binding sites for calcium ions by acid-base titration and FTIR. Finally, ITC revealed EPS to have a higher binding affinity for calcium compared, for example, to lactic acid. In conclusion, this study illustrates the role of EPS in terms of the calcium tolerance of cariogenic microbiota by determining the ability of EPS to control free calcium concentrations within the biofilms as a self-regulating mode of action in the pathogenesis of dental caries.

  12. Calcium channel blocker overdose (United States)

    ... this page: // Calcium-channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium-channel blockers are a type of medicine used ...

  13. The Plasma Membrane Calcium Pump (United States)

    Rasmussen, H.


    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.

  14. The Role of Calcium in Osteoporosis (United States)

    Arnaud, C. D.; Sanchez, S. D.


    Calcium requirements may vary throughout the lifespan. During the growth years and up to age 25 to 30, it is important to maximize dietary intake of calcium to maintain positive calcium balance and achieve peak bone mass, thereby possibly decreasing the risk of fracture when bone is subsequently lost. Calcium intake need not be greater than 800 mg/day during the relatively short period of time between the end of bone building and the onset of bone loss (30 to 40 years). Starting at age 40 to 50, both men and women lose bone slowly, but women lose bone more rapidly around the menopause and for about 10 years after. Intestinal calcium absorption and the ability to adapt to low calcium diets are impaired in many postmenopausal women and elderly persons owing to a suspected functional or absolute decrease in the ability of the kidney to produce 1,25(OH)2D2. The bones then become more and more a source of calcium to maintain critical extracellular fluid calcium levels. Excessive dietary intake of protein and fiber may induce significant negative calcium balance and thus increase dietary calcium requirements. Generally, the strongest risk factors for osteoporosis are uncontrollable (e.g., sex, age, and race) or less controllable (e.g., disease and medications). However, several factors such as diet, physical activity, cigarette smoking, and alcohol use are lifestyle related and can be modified to help reduce the risk of osteoporosis.

  15. Consumption of calcium-fortified cereal bars to improve dietary calcium intake of healthy women: randomized controlled feasibility study.

    Directory of Open Access Journals (Sweden)

    Jennifer T Lee

    Full Text Available Calcium is an important structural component of the skeletal system. Although an adequate intake of calcium helps to maintain bone health and reduce the risk of osteoporosis, many women do not meet recommended daily intakes of calcium. Previous interventions studies designed to increase dietary intake of women have utilized primarily dairy sources of calcium or supplements. However, lactose intolerance, milk protein allergies, or food preferences may lead many women to exclude important dairy sources of dietary calcium. Therefore, we undertook a 9 week randomized crossover design trial to examine the potential benefit of including a non-dairy source of calcium in the diet of women. Following a 3 week run-in baseline period, 35 healthy women > 18 years were randomized by crossover design into either Group I or Group II. Group I added 2 calcium-fortified cereal bars daily (total of 400 mg calcium/day (intervention to their usual diet and Group II continued their usual diet (control. At the end of 3 weeks, diets were switched for another 3 weeks. Intakes of calcium and energy were estimated from 3-day diet and supplemental diaries. Wilcoxon signed-rank tests were used for within group comparisons and Mann Whitney U tests were used for between group comparisons of calcium and energy intake. Dietary calcium was significantly higher during intervention (1071 mg/d when participants consumed 2 calcium-fortified cereal bars daily than during the baseline (720 mg/d, P <0.0001 or control diets (775 mg/d, P = 0.0001 periods. Furthermore, the addition of 2 calcium-fortified cereal bars daily for the 3 week intervention did not significantly increase total energy intake or result in weight gain. In conclusion, consumption of calcium-fortified cereal bars significantly increased calcium intake of women. Further research examining the potential ability of fortified cereal bars to help maintain and improve bone health of women is NCT

  16. Calcium and magnesium determination

    International Nuclear Information System (INIS)

    Bhattacharya, S.K.


    The roles of calcium and magnesium in human health and disease have been extensively studied. Calcium and magnesium have been determined in biological specimens by atomic absorption spectroscopy using stiochiometric nitrous oxide-acetylene flame

  17. Effect of dietary calcium and phosphorus on intestinal calcium absorption and vitamin D metabolism

    International Nuclear Information System (INIS)

    Ribovich, M.L.; DeLuca, H.F.


    To understand better dietary regulation of intestinal calcium absorption, a quantitative assessment of the metabolites in plasma and duodenum of rats given daily doses of radioactive vitamin D 3 and diets differing in calcium and phosphorus content was made. All known vitamin D metabolites were ultimately identified by high-pressure liquid chromatography. In addition to the known metabolites (25-hydroxyvitamin D 3 , 24,25-dihydroxyvitamin D 3 , 1,25-dihydroxyvitamin D 3 , 25,26-dihydroxyvitamin D 3 , and 1,24,25-trihydroxyvitamin D 3 ), several new and unidentified metabolites were found. In addition to 1,25-dihydroxyvitamin D 3 and 1,24,25-trihydroxyvitamin D 3 , the levels of some of the unknown metabolites could be correlated with intestinal calcium transport. However, whether or not any of these metabolites plays a role in the stimulation of intestinal calcium absorption by low dietary calcium or low dietary phosphorus remains unknown

  18. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk


    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...... affected the ash chemistry and the ash sintering tendency but much less the char reactivity. Thermo balance test are made and high-temperature X-ray diffraction measurements are performed, the experimental results indicate that with calcium addition major inorganic¿inorganic reactions take place very late...... in the char conversion process. Comprehensive global equilibrium calculations predicted important characteristics of the inorganic ash residue. Equilibrium calculations predict the formation of liquid salt if sufficient amounts of Ca are added and according to experiments as well as calculations calcium binds...

  19. Hydrolytic conversion of amorphous calcium phosphate into apatite accompanied by sustained calcium and orthophosphate ions release

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Xufeng, E-mail: [Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191 (China); BUAA Research Institute, Guangzhou 510530 (China); Research Institute of Beihang University in Shenzhen, Shenzhen 518057 (China); Chen, Siqian; Tian, Feng; Wang, Lizhen [Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191 (China); Feng, Qingling [State Key Laboratory of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China); Fan, Yubo, E-mail: [Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191 (China)


    The aim of this study is to investigate the calcium and orthophosphate ions release during the transformation of amorphous calcium phosphate (ACP) to hydroxyapatite (HA) in aqueous solution. The ACP is prepared by a wet chemical method and further immersed in the distilled water for various time points till 14 d. The release of calcium and orthophosphate ions is measured with calcium and phosphate colorimetric assay kits, respectively. The transition of ACP towards HA is detected by x-ray diffraction (XRD), transmission electron microscopy (TEM), and fourier transform infrared spectroscopy (FTIR). The results indicate that the morphological conversion of ACP to HA occurs within the first 9 h, whereas the calcium and orthophosphate ions releases last for over 7 d. Such sustained calcium and orthophosphate ions release is very useful for ACP as a candidate material for hard tissue regeneration. - Highlights: • ACP is prepared using a wet chemical method. • The conversion of crystal morphology and structure occurs mainly within the initial 9 h. • The calcium and orthophosphate ions release sustains over 14 d.

  20. Calcium homeostasis in low and high calcium water acclimatized Oreochromis mossambicus exposed to ambient and dietary cadmium

    NARCIS (Netherlands)

    Pratap, H.B.; Wendelaar Bonga, S.E.


    The effects of cadmium administered via ambient water (10 mg/l) or food (10 mgCd/fish/day) on plasma calcium, corpuscles of Stannius and bony tissues of Oreochromis mossambicus acclimated to low calcium (0.2 mM) and high calcium (0.8 mM) water were studied for 2, 4, 14 and 35 days. In low calcium

  1. 21 CFR 184.1229 - Calcium stearate. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium stearate. 184.1229 Section 184.1229 Food... Specific Substances Affirmed as GRAS § 184.1229 Calcium stearate. (a) Calcium stearate (Ca(C17H35COO)2, CAS Reg. No. 1529-23-0) is the calcium salt of stearic acid derived from edible sources. It is prepared as...

  2. 21 CFR 184.1210 - Calcium oxide. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium oxide. 184.1210 Section 184.1210 Food and... Substances Affirmed as GRAS § 184.1210 Calcium oxide. (a) Calcium oxide (CaO, CAS Reg. No. 1305-78-8) is also known as lime, quick lime, burnt lime, or calx. It is produced from calcium carbonate, limestone, or...

  3. 21 CFR 184.1193 - Calcium chloride. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium chloride. 184.1193 Section 184.1193 Food... Specific Substances Affirmed as GRAS § 184.1193 Calcium chloride. (a) Calcium chloride (CaCl2·2H2O, CAS Reg. No. 10035-04-8) or anhydrous calcium chloride (CaCl2, CAS Reg. No. 10043-52-4) may be commercially...

  4. A Crash Course in Calcium Channels. (United States)

    Zamponi, Gerald W


    Much progress has been made in understanding the molecular physiology and pharmacology of calcium channels. Recently, there have been tremendous advances in learning about calcium channel structure and function through crystallography and cryo-electron microscopy studies. Here, I will give an overview of our knowledge about calcium channels, and highlight two recent studies that give important insights into calcium channel structure.

  5. Fermentation of calcium-fortified soymilk with Lactobacillus: effects on calcium solubility, isoflavone conversion, and production of organic acids. (United States)

    Tang, A L; Shah, N P; Wilcox, G; Walker, K Z; Stojanovska, L


    The objective of this study was to enhance calcium solubility and bioavailability from calcium-fortified soymilk by fermentation with 7 strains of Lactobacillus, namely, L. acidophilus ATCC 4962, ATCC33200, ATCC 4356, ATCC 4461, L. casei ASCC 290, L. plantarum ASCC 276, and L. fermentum VRI-003. The parameters that were used are viability, pH, calcium solubility, organic acid, and biologically active isoflavone aglycone content. Calcium-fortified soymilk made from soy protein isolate was inoculated with these probiotic strains, incubated for 24 h at 37 degrees C, then stored for 14 d at 4 degrees C. Soluble calcium was measured using atomic absorption spectrophotometry (AA). Organic acids and bioactive isoflavone aglycones, including diadzein, genistein, and glycetein, were measured using HPLC. Viability of the strains in the fermented calcium-fortified soymilk was > 8.5 log(10) CFU/g after 24 h fermentation and this was maintained for 14-d storage at 4 degrees C. After 24 h, there was a significant increase (P casei ASCC 290 demonstrated the highest increase with 89.3% and 87.0% soluble calcium after 24 h, respectively. The increase in calcium solubility observed was related to lowered pH associated with production of lactic and acetic acids. Fermentation significantly increased (P < 0.05) the level of conversion of isoflavones into biologically active aglycones, including diadzein, genistein, and glycetein. Our results show that fermenting calcium-fortified soymilk with the selected probiotics can potentially enhance the calcium bioavailability of calcium-fortified soymilk due to increased calcium solubility and bioactive isoflavone aglycone enrichment.

  6. Intracellular sphingosine releases calcium from lysosomes. (United States)

    Höglinger, Doris; Haberkant, Per; Aguilera-Romero, Auxiliadora; Riezman, Howard; Porter, Forbes D; Platt, Frances M; Galione, Antony; Schultz, Carsten


    To elucidate new functions of sphingosine (Sph), we demonstrate that the spontaneous elevation of intracellular Sph levels via caged Sph leads to a significant and transient calcium release from acidic stores that is independent of sphingosine 1-phosphate, extracellular and ER calcium levels. This photo-induced Sph-driven calcium release requires the two-pore channel 1 (TPC1) residing on endosomes and lysosomes. Further, uncaging of Sph leads to the translocation of the autophagy-relevant transcription factor EB (TFEB) to the nucleus specifically after lysosomal calcium release. We confirm that Sph accumulates in late endosomes and lysosomes of cells derived from Niemann-Pick disease type C (NPC) patients and demonstrate a greatly reduced calcium release upon Sph uncaging. We conclude that sphingosine is a positive regulator of calcium release from acidic stores and that understanding the interplay between Sph homeostasis, calcium signaling and autophagy will be crucial in developing new therapies for lipid storage disorders such as NPC.

  7. 21 CFR 184.1185 - Calcium acetate. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium acetate. 184.1185 Section 184.1185 Food and... Substances Affirmed as GRAS § 184.1185 Calcium acetate. (a) Calcium acetate (Ca (C2H3O2)2, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be...

  8. Impaired body calcium metabolism with low bone density and compensatory colonic calcium absorption in cecectomized rats

    NARCIS (Netherlands)

    Jongwattanapisan, P.; Suntornsaratoon, P.; Wongdee, K.; Dorkkam, N.; Krishnamra, N.; Charoenphandhu, N.


    An earlier study reported that cecal calcium absorption contributes less than 10% of total calcium absorbed by the intestine, although the cecum has the highest calcium transport rate compared with other intestinal segments. Thus, the physiological significance of the cecum pertaining to body


    Energy Technology Data Exchange (ETDEWEB)

    Langton, C.; Stefanko, D.


    The objective of this report is to document laboratory testing of blended calcium aluminate - calcium hemihydrate grouts for P-Reactor vessel in-situ decommissioning. Blended calcium aluminate - calcium hemihydrate cement-based grout was identified as candidate material for filling (physically stabilizing) the 105-P Reactor vessel (RV) because it is less alkaline than portland cement-based grout which has a pH greater than 12.4. In addition, blended calcium aluminate - calcium hemihydrate cement compositions can be formulated such that the primary cementitious phase is a stable crystalline material. A less alkaline material (pH {<=} 10.5) was desired to address a potential materials compatibility issue caused by corrosion of aluminum metal in highly alkaline environments such as that encountered in portland cement grouts [Wiersma, 2009a and b, Wiersma, 2010, and Serrato and Langton, 2010]. Information concerning access points into the P-Reactor vessel and amount of aluminum metal in the vessel is provided elsewhere [Griffin, 2010, Stefanko, 2009 and Wiersma, 2009 and 2010, Bobbitt, 2010, respectively]. Radiolysis calculations are also provided in a separate document [Reyes-Jimenez, 2010].

  10. Timing of the calcium intake and effect of calcium deficiency on behaviour and egg laying in captive great tits, Parus major. (United States)

    Graveland, J; Berends, A E


    The calcium demand of egg-laying birds is much higher than in other vertebrates during reproduction. We showed elsewhere that a low level of calcium availability can greatly affect the eggshell quality and reproduction of free-living passerines. However, there are few data on calcium demand and calcium intake in relation to egg laying and behaviour and egg-laying performance under conditions of calcium shortage in nondomesticated birds. We examined these aspects in an experiment with captive great tits, Parus major, on a diet deficient in calcium, with or without snail shells as an additional calcium source. More than 90% of the calcium intake for egg production took place during the egg-laying period. Females ingested about 1.7 times as much calcium as they deposited in eggshells. Removing the snail shells after the first egg resulted in eggshell defects and interruptions of laying after 1-3 d. Females without snail shells doubled their searching effort and started to burrow in the soil and to eat sand, small stones, and their own eggs. Most calcium was consumed in the evening, probably to supplement the calcium available from the medullary bone with an additional calcium source in the gut during eggshell formation. The results demonstrated that eggshell formation requires accurate timing of the calcium intake and that obtaining sufficient calcium is time-consuming, even in calcium-rich environments. These factors pertaining to calcium intake greatly affect the ability of birds to collect sufficient calcium for eggshell formation in calcium-poor areas.

  11. Calcium, vitamin D, and your bones (United States)

    ... page: // Calcium, vitamin D, and your bones To use the sharing ... and maintain strong bones. How Much Calcium and Vitamin D do I Need? Amounts of calcium are ...

  12. Calcium-sensing beyond neurotransmitters

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Han, Weiping


    Neurotransmitters, neuropeptides and hormones are released through the regulated exocytosis of SVs (synaptic vesicles) and LDCVs (large dense-core vesicles), a process that is controlled by calcium. Synaptotagmins are a family of type 1 membrane proteins that share a common domain structure. Most....... Also, we discuss potential roles of synaptotagmins in non-traditional endocrine systems....... synaptotagmins are located in brain and endocrine cells, and some of these synaptotagmins bind to phospholipids and calcium at levels that trigger regulated exocytosis of SVs and LDCVs. This led to the proposed synaptotagmin-calcium-sensor paradigm, that is, members of the synaptotagmin family function...... as calcium sensors for the regulated exocytosis of neurotransmitters, neuropeptides and hormones. Here, we provide an overview of the synaptotagmin family, and review the recent mouse genetic studies aimed at understanding the functions of synaptotagmins in neurotransmission and endocrine-hormone secretion...

  13. Calcium carboorthovanadate - a new compound with the apa

    International Nuclear Information System (INIS)

    Slobodin, B.V.; Dmitrieva, O.I.; Fotiev, A.A.


    Data on calcium carboorthovanadate, Ca 10 (VO 4 ) 6 CO 3 , a new compound with an appatite structure based on calcium orthovanadate, are reported. The synthesis has been conducted in a stoichiometric mixture of finely ground calcium carbonate and calcium orthovanadate. It is found that calcium carboorthovanadate belongs to the hexagonal syngony and has an apatite structure. An analysis of the infrared spectra of initial compounds and calcium carboorthovanadate confirmed the presence of carbonate (CO 3 ) 2- and orthovanadate (VO 4 ) 3 groupings in the latter. On heating in air, beginning with 450 deg C calcium carboorthovanadate decomposes at a slow rate into calcium oxide, calcium orthovanadate, and carbon dioxide

  14. Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, Hilbert


    By means of homogeneous precipitation it has been possible to synthesize crystalline solid solutions of calcium strontium hydroxyapatite from aqueous solutions. The lattice constants for the solid solutions were measured in the range Ca{sub 9}Sr(PO{sub 4}){sub 6}(OH){sub 2} - CaSr{sub 9}(PO{sub 4}){sub 6}(OH){sub 2}. The investigations show that the discrimination of strontium against calcium is considerably smaller than reported elsewhere (1). Strontium is preferentially built into the c-axis direction of the apatite lattice.

  15. Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems. (United States)

    Hofmeyr, G Justus; Lawrie, Theresa A; Atallah, Alvaro N; Duley, Lelia; Torloni, Maria R


    Pre-eclampsia and eclampsia are common causes of serious morbidity and death. Calcium supplementation may reduce the risk of pre-eclampsia, and may help to prevent preterm birth. To assess the effects of calcium supplementation during pregnancy on hypertensive disorders of pregnancy and related maternal and child outcomes. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (28 March 2013) and contacted study authors for more data where possible. We updated the search in May 2014 and added the results to the 'Awaiting Classification' section of the review. Randomised controlled trials (RCTs) comparing high-dose (at least 1 g daily of calcium) or low-dose calcium supplementation during pregnancy with placebo or no calcium. We assessed eligibility and trial quality, extracted and double-entered data. High-dose calcium supplementation (≥1 g/day)We included 14 studies in the review, however one study contributed no data. We included 13 high-quality studies in our meta-analyses (15,730 women). The average risk of high blood pressure (BP) was reduced with calcium supplementation compared with placebo (12 trials, 15,470 women: risk ratio (RR) 0.65, 95% confidence interval (CI) 0.53 to 0.81; I² = 74%). There was also a significant reduction in the risk of pre-eclampsia associated with calcium supplementation (13 trials, 15,730 women: RR 0.45, 95% CI 0.31 to 0.65; I² = 70%). The effect was greatest for women with low calcium diets (eight trials, 10,678 women: average RR 0.36, 95% CI 0.20 to 0.65; I² = 76%) and women at high risk of pre-eclampsia (five trials, 587 women: average RR 0.22, 95% CI 0.12 to 0.42; I² = 0%). These data should be interpreted with caution because of the possibility of small-study effect or publication bias.The composite outcome maternal death or serious morbidity was reduced (four trials, 9732 women; RR 0.80, 95% CI 0.65 to 0.97; I² = 0%). Maternal deaths were not significantly different (one trial of 8312 women: calcium

  16. 36 CFR 1207.36 - Procurement. (United States)


    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Procurement. 1207.36 Section 1207.36 Parks, Forests, and Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION GENERAL RULES... resonableness can be established on the basis of a catalog or market price of a commercial product sold in...

  17. 21 CFR 184.1195 - Calcium citrate. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium citrate. 184.1195 Section 184.1195 Food and... Substances Affirmed as GRAS § 184.1195 Calcium citrate. (a) Calcium citrate (Ca3(C6H5O7)2·4H2O, CAS Reg. No. 813-0994-095) is the calcium salt of citric acid. It is prepared by neutralizing citric acid with...

  18. Characterization of Calcium Compounds in Opuntia ficus indica as a Source of Calcium for Human Diet

    Directory of Open Access Journals (Sweden)

    Isela Rojas-Molina


    Full Text Available Analyses of calcium compounds in cladodes, soluble dietary fiber (SDF, and insoluble dietary fiber (IDF of Opuntia ficus indica are reported. The characterization of calcium compounds was performed by using Scanning Electron Microscopy, Energy Dispersive Spectrometry, X-ray diffraction, and infrared spectroscopy. Atomic Absorption Spectroscopy and titrimetric methods were used for quantification of total calcium and calcium compounds. Whewellite (CaC2O4·H2O, weddellite (CaC2O4·(H2O2.375, and calcite (CaCO3 were identified in all samples. Significant differences (P≤0.05 in the total calcium contents were detected between samples. CaC2O4·H2O content in cladodes and IDF was significantly higher (P≤0.05 in comparison to that observed in SDF, whereas minimum concentration of CaCO3 was detected in IDF with regard to CaCO3 contents observed in cladodes and SDF. Additionally, molar ratio oxalate : Ca2+ in all samples changed in a range from 0.03 to 0.23. These results support that calcium bioavailability in O. ficus indica modifies according to calcium compounds distribution.

  19. Electrophoretic mobility shift in native gels indicates calcium-dependent structural changes of neuronal calcium sensor proteins. (United States)

    Viviano, Jeffrey; Krishnan, Anuradha; Wu, Hao; Venkataraman, Venkat


    In proteins of the neuronal calcium sensor (NCS) family, changes in structure as well as function are brought about by the binding of calcium. In this article, we demonstrate that these structural changes, solely due to calcium binding, can be assessed through electrophoresis in native gels. The results demonstrate that the NCS proteins undergo ligand-dependent conformational changes that are detectable in native gels as a gradual decrease in mobility with increasing calcium but not other tested divalent cations such as magnesium, strontium, and barium. Surprisingly, such a gradual change over the entire tested range is exhibited only by the NCS proteins but not by other tested calcium-binding proteins such as calmodulin and S100B, indicating that the change in mobility may be linked to a unique NCS family feature--the calcium-myristoyl switch. Even within the NCS family, the changes in mobility are characteristic of the protein, indicating that the technique is sensitive to the individual features of the protein. Thus, electrophoretic mobility on native gels provides a simple and elegant method to investigate calcium (small ligand)-induced structural changes at least in the superfamily of NCS proteins. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. The Risks and Benefits of Calcium Supplementation

    Directory of Open Access Journals (Sweden)

    Chan Soo Shin


    Full Text Available The association between calcium supplementation and adverse cardiovascular events has recently become a topic of debate due to the publication of two epidemiological studies and one meta-analysis of randomized controlled clinical trials. The reports indicate that there is a significant increase in adverse cardiovascular events following supplementation with calcium; however, a number of experts have raised several issues with these reports such as inconsistencies in attempts to reproduce the findings in other populations and questions concerning the validity of the data due to low compliance, biases in case ascertainment, and/or a lack of adjustment. Additionally, the Auckland Calcium Study, the Women's Health Initiative, and many other studies included in the meta-analysis obtained data from calcium-replete subjects and it is not clear whether the same risk profile would be observed in populations with low calcium intakes. Dietary calcium intake varies widely throughout the world and it is especially low in East Asia, although the risk of cardiovascular events is less prominent in this region. Therefore, clarification is necessary regarding the occurrence of adverse cardiovascular events following calcium supplementation and whether this relationship can be generalized to populations with low calcium intakes. Additionally, the skeletal benefits from calcium supplementation are greater in subjects with low calcium intakes and, therefore, the risk-benefit ratio of calcium supplementation is likely to differ based on the dietary calcium intake and risks of osteoporosis and cardiovascular diseases of various populations. Further studies investigating the risk-benefit profiles of calcium supplementation in various populations are required to develop population-specific guidelines for individuals of different genders, ages, ethnicities, and risk profiles around the world.

  1. Thermoluminescence of calcium-based phosphors

    International Nuclear Information System (INIS)

    Sunta, C.M.


    The paper reviews the thermoluminescence (TL) properties of calcium fluoride, calcium sulphate and calcium carbonate phosphors. In the case of the calcium fluoride mineral phosphor the main emitter of TL is the cerium impurity. Based on the TL emission spectra, two types of Ce 3+ centres can be easily distinguished; those associated with O 2- compensating ion and those which have either no local compensators or are associated with F - interstitial ions at the adjacent vacant body centre position. The spectra undergo remarkable changes at high doses. Such changes are associated with the probabilities of charge trapping at different types of traps and also with the probabilities of recombination at different types of luminescent centres. Some of the traps and recombination centres are spatially associated while others are distributed randomly. In calcium carbonate mineral, Mn 2+ is invariably the emitting impurity. Mn 2+ can be used as an efficient dopant for TL emission in all the three calcium based TL phosphors. A co-dopant like Ce 3+ intensifies the luminescence yield from Mn 2+ . Models of different types of electron and hole trapping centres are given. (author)

  2. Calcium channel blockers and Alzheimer's disease★ (United States)

    Tan, Yi; Deng, Yulin; Qing, Hong


    Alzheimer's disease is characterized by two pathological hallmarks: amyloid plaques and neurofibrillary tangles. In addition, calcium homeostasis is disrupted in the course of human aging. Recent research shows that dense plaques can cause functional alteration of calcium signals in mice with Alzheimer's disease. Calcium channel blockers are effective therapeutics for treating Alzheimer's disease. This review provides an overview of the current research of calcium channel blockers involved in Alzheimer's disease therapy. PMID:25767489

  3. Short communication: Urinary oxalate and calcium excretion by dogs and cats diagnosed with calcium oxalate urolithiasis

    NARCIS (Netherlands)

    Dijcker, J.C.; Kummeling, A.; Hagen-Plantinga, E.A.; Hendriks, W.H.


    Introduction Urine concentrations of oxalate and calcium play an important role in calcium oxalate (CaOx) urolith formation in dogs and cats, with high excretions of both substances increasing the chance of CaOx urolithiasis. In 17 CaOx-forming dogs, urine calcium:creatinine ratio (Ca:Cr) was found

  4. Contracture of Slow Striated Muscle during Calcium Deprivation (United States)

    Irwin, Richard L.; Hein, Manfred M.


    When deprived of calcium the slow striated muscle fibers of the frog develop reversible contractures in either hypertonic or isotonic solutions. While calcium deprivation continues because of a flowing calcium-free solution the muscles relax slowly and completely. Restoration of calcium during contracture relaxes the muscle promptly to initial tension. When relaxed during calcium lack the return of calcium does not change tension and the muscle stays relaxed. When contractures are induced by solutions containing small amounts of calcium relaxation does not occur or requires several hours. The rate of tension development depends upon the rate at which calcium moves outward since the contractures develop slower in low concentrations of calcium and are absent or greatly slowed in a stagnant calcium-free solution. Withdrawal of calcium prevents the contractile responses to ACh, KCl, or electrical stimulation through the nerve. Muscles return to their original excitability after calcium is restored. Origin of the contractures is unrelated to nerve activity since they are maximal during transmission failure from calcium lack, occur in denervated muscles, and are not blocked by high concentrations of d-tubocurarine, procaine, or atropine. The experiments also indicate that the contractures do not originate from repetitive activity of muscle membranes. The findings are most simply explained by relating the outward movement of calcium as a link for initiating contraction in slow type striated muscle. PMID:14065284

  5. Rapid screening assay for calcium bioavailability studies

    International Nuclear Information System (INIS)

    Luhrsen, K.R.; Hudepohl, G.R.; Smith, K.T.


    Calcium bioavailability has been studied by numerous techniques. The authors report here the use of the gamma emitting isotope of calcium ( 47 Ca) in a whole body retention assay system. In this system, calcium sources are administered by oral gavage and subsequent counts are determined and corrected for isotopic decay. Unlike iron and zinc retention curves, which exhibit a 2-3 day equilibration period, calcium reaches equilibration after 24 hours. Autoradiographic analysis of the femurs indicate that the newly absorbed calcium is rapidly distributed to the skeletal system. Moreover, the isotope is distributed along the entire bone. Comparisons of calcium bioavailability were made using intrinsic/extrinsic labeled milk from two species i.e. rat and goat as well as CaCO 3 . In addition, extrinsic labeled cow milk was examined. In the rat, the extrinsic labeled calcium from milk was better absorbed than the intrinsic calcium. This was not the case in goat milk or the calcium carbonate which exhibited no significant differences. Chromatographic analysis of the labeled milk indicates a difference in distribution of the 47 Ca. From these data, the authors recommend the use of this assay system in calcium bioavailability studies. The labeling studies and comparisons indicate caution should be used, however, in labeling techniques and species milk comparison

  6. Store-Operated Calcium Entries Control Neural Stem Cell Self-Renewal in the Adult Brain Subventricular Zone. (United States)

    Domenichini, Florence; Terrié, Elodie; Arnault, Patricia; Harnois, Thomas; Magaud, Christophe; Bois, Patrick; Constantin, Bruno; Coronas, Valérie


    The subventricular zone (SVZ) is the major stem cell niche in the brain of adult mammals. Within this region, neural stem cells (NSC) proliferate, self-renew and give birth to neurons and glial cells. Previous studies underlined enrichment in calcium signaling-related transcripts in adult NSC. Because of their ability to mobilize sustained calcium influxes in response to a wide range of extracellular factors, store-operated channels (SOC) appear to be, among calcium channels, relevant candidates to induce calcium signaling in NSC whose cellular activities are continuously adapted to physiological signals from the microenvironment. By Reverse Transcription Polymerase Chain Reaction (RT-PCR), Western blotting and immunocytochemistry experiments, we demonstrate that SVZ cells express molecular actors known to build up SOC, namely transient receptor potential canonical 1 (TRPC1) and Orai1, as well as their activator stromal interaction molecule 1 (STIM1). Calcium imaging reveals that SVZ cells display store-operated calcium entries. Pharmacological blockade of SOC with SKF-96365 or YM-58483 (also called BTP2) decreases proliferation, impairs self-renewal by shifting the type of SVZ stem cell division from symmetric proliferative to asymmetric, thereby reducing the stem cell population. Brain section immunostainings show that TRPC1, Orai1, and STIM1 are expressed in vivo, in SOX2-positive SVZ NSC. Injection of SKF-96365 in brain lateral ventricle diminishes SVZ cell proliferation and reduces the ability of SVZ cells to form neurospheres in vitro. The present study combining in vitro and in vivo approaches uncovers a major role for SOC in the control of SVZ NSC population and opens new fields of investigation for stem cell biology in health and disease. Stem Cells 2018;36:761-774. © AlphaMed Press 2018.

  7. Calcium-rich biochar from the pyrolysis of crab shell for phosphorus removal. (United States)

    Dai, Lichun; Tan, Furong; Li, Hong; Zhu, Nengmin; He, Mingxiong; Zhu, Qili; Hu, Guoquan; Wang, Li; Zhao, Jie


    Calcium-rich biochars (CRB) prepared through pyrolysis of crab shell at various temperatures were characterized for physicochemical properties and P removal potential. Elemental analysis showed that CRB was rich in calcium (22.91%-36.14%), while poor in carbon (25.21%-9.08%). FTIR, XRD and TG analyses showed that calcite-based CRB was prepared at temperature ≤600 °C, while lime-based CRB was prepared at temperature ≥700 °C. Phosphorus removal experiment showed that P removal efficiencies in 80 mg P/L phosphate solution and biogas effluent ranged from 26% to 11%, respectively, to about 100% and 63%, respectively, depending on the pyrolysis temperature of the resulting biochar. Specifically, compared to common used CaCO 3 and Ca(OH) 2 , P removal potential of calcite-based CRB was much higher than that of CaCO 3 ; while that of lime-based CRB was close to that of Ca(OH) 2 . These results suggested that CRB was competent for P removal/recovery from wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Calcium movements and the cellular basis of gravitropism (United States)

    Roux, S. J.; Biro, R. L.; Hale, C. C.

    An early gravity-transduction event in oat coleoptiles which precedes any noticeable bending is the accumulation of calcium on their prospective slower-growing side. Sub-cellular calcium localization studies indicate that the gravity-stimulated redistribution of calcium results in an increased concentration of calcium in the walls of responding cells. Since calcium can inhibit the extension growth of plant cell walls, this selective accumulation of calcium in walls may play a role in inducing the asymmetry of growth which characterizes gravitropism. The active transport of calcium from cells into walls is performed by a calcium-dependent ATPase localized in the plasma membrane. Evidence is presented in support of the hypothesis that this calcium pump is regulated by a feed-back mechanism which includes the participation of calmodulin.

  9. Plasma concentration of ionized calcium in healthy iguanas. (United States)

    Dennis, P M; Bennett, R A; Harr, K E; Lock, B A


    To measure plasma concentration of ionized calcium in healthy green iguanas. Prospective study. 9 juvenile and 21 (10 male, 11 female) adult iguanas. Blood samples were obtained from each iguana, and plasma calcium, glucose, phosphorus, uric acid, total protein, albumin, globulin, potassium, and ionized calcium concentrations, aspartate transaminase (AST) activity, and pH were measured. Heparinized blood was used for measurement of ionized calcium concentration and blood pH. A CBC was also performed to assess the health of the iguanas. Significant differences were not detected among the 3 groups (juveniles, males, and females) with regard to ionized calcium concentration. Mean ionized calcium concentration measured in blood was 1.47 +/- 0.105 mmol/L. Significant differences were detected between juveniles and adults for values of phosphorus, glucose, total protein, albumin, globulin, and AST activity. Ionized calcium concentration provides a clinical measurement of the physiologically active calcium in circulation. Evaluation of physiologically active calcium in animals with suspected calcium imbalance that have total plasma calcium concentrations within reference range or in gravid animals with considerably increased total plasma calcium concentrations is vital for determining a therapeutic plan. Accurate evaluation of calcium status will provide assistance in the diagnosis of renal disease and seizures and allow for better evaluation of the health status of gravid female iguanas.

  10. Effect of calcium chloride treatments on calcium content, anthracnose severity and antioxidant activity in papaya fruit during ambient storage. (United States)

    Madani, Babak; Mirshekari, Amin; Yahia, Elhadi


    There have been no reports on the effects of preharvest calcium application on anthracnose disease severity, antioxidant activity and cellular changes during ambient storage of papaya, and therefore the objective of this study was to investigate these effects. Higher calcium concentrations (1.5 and 2% w/v) increased calcium concentration in the peel and pulp tissues, maintained firmness, and reduced anthracnose incidence and severity. While leakage of calcium-treated fruit was lower for 1.5 and 2% calcium treatments compared to the control, microscopic results confirmed that pulp cell wall thickness was higher after 6 days in storage, for the 2% calcium treatment compared to the control. Calcium-treated fruit also had higher total antioxidant activity and total phenolic compounds during storage. Calcium chloride, especially at higher concentrations, is effective in maintaining papaya fruit quality during ambient storage. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  11. Multiparameter imaging of calcium and abscisic acid and high-resolution quantitative calcium measurements using R-GECO1-mTurquoise in Arabidopsis. (United States)

    Waadt, Rainer; Krebs, Melanie; Kudla, Jörg; Schumacher, Karin


    Calcium signals occur in specific spatio-temporal patterns in response to various stimuli and are coordinated with, for example, hormonal signals, for physiological and developmental adaptations. Quantification of calcium together with other signalling molecules is required for correlative analyses and to decipher downstream calcium-decoding mechanisms. Simultaneous in vivo imaging of calcium and abscisic acid has been performed here to investigate the interdependence of the respective signalling processes in Arabidopsis thaliana roots. Advanced ratiometric genetically encoded calcium indicators have been generated and in vivo calcium calibration protocols were established to determine absolute calcium concentration changes in response to auxin and ATP. In roots, abscisic acid induced long-term basal calcium concentration increases, while auxin triggered rapid signals in the elongation zone. The advanced ratiometric calcium indicator R-GECO1-mTurquoise exhibited an increased calcium signal resolution compared to commonly used Förster resonance energy transfer-based indicators. Quantitative calcium measurements in Arabidopsis root tips using R-GECO1-mTurquoise revealed detailed maps of absolute calcium concentration changes in response to auxin and ATP. Calcium calibration protocols using R-GECO1-mTurquoise enabled high-resolution quantitative imaging of resting cytosolic calcium concentrations and their dynamic changes that revealed distinct hormonal and ATP responses in roots. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  12. Presynaptic calcium signalling in cerebellar mossy fibres

    DEFF Research Database (Denmark)

    Thomsen, Louiza Bohn; Jörntell, Henrik; Midtgaard, Jens


    Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A tetrodotoxin (TTX......)-sensitive fast Na(+) spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers....... Calcium imaging using Calcium-Green dextran revealed a stimulus-evoked all-or-none TTX-sensitive calcium signal in simple and complex rosettes. All compartments of a complex rosette were activated during electrical activation of the mossy fibre, while individual simple and complex rosettes along an axon...

  13. Calcium Chloride and Calcium Gluconate in Neonatal Parenteral Nutrition Solutions without Cysteine: Compatibility Studies Using Laser Light Obscuration Methodology

    Directory of Open Access Journals (Sweden)

    Robert K. Huston


    Full Text Available There are no compatibility studies for neonatal parenteral nutrition solutions without cysteine containing calcium chloride or calcium gluconate using light obscuration as recommended by the United States Pharmacopeia (USP. The purpose of this study was to do compatibility testing for solutions containing calcium chloride and calcium gluconate without cysteine. Solutions of TrophAmine and Premasol (2.5% amino acids, containing calcium chloride or calcium gluconate were compounded without cysteine. Solutions were analyzed for particle counts using light obscuration. Maximum concentrations tested were 15 mmol/L of calcium and 12.5 mmol/L of phosphate. If the average particle count of three replicates exceeded USP guidelines, the solution was determined to be incompatible. This study found that 12.5 and 10 mmol/L of calcium and phosphate, respectively, are compatible in neonatal parenteral nutrition solutions compounded with 2.5% amino acids of either TrophAmine or Premasol. There did not appear to be significant differences in compatibility for solutions containing TrophAmine or Premasol when solutions were compounded with either CaCl2 or CaGlu-Pl. This study presents data in order to evaluate options for adding calcium and phosphate to neonatal parenteral nutrition solutions during shortages of calcium and cysteine.

  14. Vitamin D and Calcium Addition during Denosumab Therapy over a Period of Four Years Significantly Improves Lumbar Bone Mineral Density in Japanese Osteoporosis Patients

    Directory of Open Access Journals (Sweden)

    Takako Suzuki


    Full Text Available This study investigated whether or not vitamin D and calcium supplementation affected bone metabolism and bone mineral density (BMD over a period of four years of denosumab therapy in patients with primary osteoporosis. Patients were divided into a denosumab monotherapy group (22 cases or a denosumab plus vitamin D and calcium supplementation group (combination group, 21 cases. We measured serum bone alkaline phosphatase (BAP, tartrate-resistant acid phosphatase (TRACP-5b, urinary N-terminal telopeptide of type-I collagen (NTX, and BMD of the lumbar 1–4 vertebrae (L-BMD and bilateral hips (H-BMD at baseline and at 12, 24, 36, and 48 months of treatment. There were no significant differences in patient background. Serum BAP, TRACP-5b, and urinary NTX were significantly and comparably inhibited in both groups from 12 to 48 months versus baseline values. L-BMD was significantly increased at every time point in both groups, while H-BMD was significantly increased at every time point in the combination group only. There were significant differences between the groups for L-BMD at 24, 36, and 48 months (P < 0.05 and for H-BMD at 12 months (P < 0.05. Compared with denosumab monotherapy, combination therapy of denosumab plus vitamin D and calcium significantly increased H-BMD at 12 months and L-BMD from 24 to 48 months. These findings indicate that continuous vitamin D and calcium supplementation is important, especially for 12 months to improve H-BMD and from 24 to 48 months to improve L-BMD.

  15. High calcium concentration in bones promotes bone metastasis in renal cell carcinomas expressing calcium-sensing receptor. (United States)

    Joeckel, Elke; Haber, Tobias; Prawitt, Dirk; Junker, Kerstin; Hampel, Christian; Thüroff, Joachim W; Roos, Frederik C; Brenner, Walburgis


    The prognosis for renal cell carcinoma (RCC) is related to a high rate of metastasis, including 30% of bone metastasis. Characteristic for bone tissue is a high concentration of calcium ions. In this study, we show a promoting effect of an enhanced extracellular calcium concentration on mechanisms of bone metastasis via the calcium-sensing receptor (CaSR) and its downstream signaling molecules. Our analyses were performed using 33 (11/category) matched specimens of normal and tumor tissue and 9 (3/category) primary cells derived from RCC patients of the 3 categories: non-metastasized, metastasized into the lung and metastasized into bones during a five-year period after nephrectomy. Expression of CaSR was determined by RT-PCR, Western blot analyses and flow cytometry, respectively. Cells were treated by calcium and the CaSR inhibitor NPS 2143. Cell migration was measured in a Boyden chamber with calcium (10 μM) as chemotaxin and proliferation by BrdU incorporation. The activity of intracellular signaling mediators was quantified by a phospho-kinase array and Western blot. The expression of CaSR was highest in specimens and cells of patients with bone metastases. Calcium treatment induced an increased migration (19-fold) and proliferation (2.3-fold) exclusively in RCC cells from patients with bone metastases. The CaSR inhibitor NPS 2143 elucidated the role of CaSR on the calcium-dependent effects. After treatment with calcium, the activity of AKT, PLCγ-1, p38α and JNK was clearly enhanced and PTEN expression was almost completely abolished in bone metastasizing RCC cells. Our results indicate a promoting effect of extracellular calcium on cell migration and proliferation of bone metastasizing RCC cells via highly expressed CaSR and its downstream signaling pathways. Consequently, CaSR may be regarded as a new prognostic marker predicting RCC bone metastasis.

  16. Calcium Intake in Elderly Australian Women Is Inadequate

    Directory of Open Access Journals (Sweden)

    Colin W. Binns


    Full Text Available The role of calcium in the prevention of bone loss in later life has been well established but little data exist on the adequacy of calcium intakes in elderly Australian women. The aim of this study was to compare the dietary intake including calcium of elderly Australian women with the Australian dietary recommendation, and to investigate the prevalence of calcium supplement use in this population. Community-dwelling women aged 70–80 years were randomly recruited using the Electoral Roll for a 2-year protein intervention study in Western Australia. Dietary intake was assessed at baseline by a 3-day weighed food record and analysed for energy, calcium and other nutrients. A total of 218 women were included in the analysis. Mean energy intake was 7,140 ± 1,518 kJ/day and protein provided 19 ± 4% of energy. Mean dietary calcium intake was 852 ± 298 mg/day, which is below Australian recommendations. Less than one quarter of women reported taking calcium supplements and only 3% reported taking vitamin D supplements. Calcium supplements by average provided calcium 122 ± 427 mg/day and when this was taken into account, total calcium intake increased to 955 ± 504 mg/day, which remained 13% lower than the Estimated Average Requirement (EAR, 1,100 mg/day for women of this age group. The women taking calcium supplements had a higher calcium intake (1501 ± 573 mg compared with the women on diet alone (813 ± 347 mg. The results of this study indicate that the majority of elderly women were not meeting their calcium requirements from diet alone. In order to achieve the recommended dietary calcium intake, better strategies for promoting increased calcium, from both diet and calcium supplements appears to be needed.

  17. Mitigation of nitrous oxide (N2O) emissions from denitrifying fluidized bed bioreactors (DFBBRs) using calcium. (United States)

    Eldyasti, Ahmed; Nakhla, George; Zhu, Jesse


    Nitrous oxide (N2O) is a significant anthropogenic greenhouse gases (AnGHGs) emitted from biological nutrient removal (BNR) processes. In this study, N2O production from denitrifying fluidized bed bioreactors (DFBBR) was reduced using calcium (Ca2+) dosage. The DFBBRs were operated on a synthetic municipal wastewater at four different calcium concentrations ranging from the typical municipal wastewater Ca2+ concentration (60 mg Ca2+/L) to 240 mg Ca2+/L at two different COD/N ratios. N2O emission rates, extracellular polymeric substances (EPS), water quality parameters, and microscopic images were monitored regularly in both phases. Calcium concentrations played a significant role in biofilm morphology with the detachment rates for R120Ca, R180Ca, and R240Ca 75% lower than for R60Ca, respectively. The N2O conversion rate at the typical municipal wastewater Ca2+ concentration (R60Ca) was about 0.53% of the influent nitrogen loading as compared with 0.34%, 0.42%, and 0.41% for R120Ca, R180Ca, and R240Ca, respectively corresponding to 21-36% reduction. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. 7 CFR 58.434 - Calcium chloride. (United States)


    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Calcium chloride. 58.434 Section 58.434 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.434 Calcium chloride. Calcium chloride, when used, shall meet the requirements of the Food...

  19. Seasonal Variations in Mercury's Dayside Calcium Exosphere (United States)

    Burger, Matthew H.; Killen, Rosemary M.; McClintock, William E.; Merkel, Aimee W.; Vervack, Ronald J., Jr.; Cassidy, Timothy A.; Sarantos, Menelaos


    The Mercury Atmospheric and Surface Composition Spectrometer on the MESSENGER spacecraft has observed calcium emission in Mercury's exosphere on a near-daily basis since March 2011. During MESSENGER's primary and first extended missions (March 2011 - March 2013) the dayside calcium exosphere was measured over eight Mercury years. We have simulated these data with a Monte Carlo model of exospheric source processes to show that (a) there is a persistent source of energetic calcium located in the dawn equatorial region, (b) there is a seasonal dependence in the calcium source rate, and (c) there are no obvious year-to-year variations in the near-surface dayside calcium exosphere. Although the precise mechanism responsible for ejecting the calcium has not yet been determined, the most likely process is the dissociation of Ca-bearing molecules produced in micrometeoroid impact plumes to form energetic, escaping calcium atoms.

  20. Altered Elementary Calcium Release Events and Enhanced Calcium Release by Thymol in Rat Skeletal Muscle


    Szentesi, Péter; Szappanos, Henrietta; Szegedi, Csaba; Gönczi, Monika; Jona, István; Cseri, Julianna; Kovács, László; Csernoch, László


    The effects of thymol on steps of excitation-contraction coupling were studied on fast-twitch muscles of rodents. Thymol was found to increase the depolarization-induced release of calcium from the sarcoplasmic reticulum, which could not be attributed to a decreased calcium-dependent inactivation of calcium release channels/ryanodine receptors or altered intramembrane charge movement, but rather to a more efficient coupling of depolarization to channel opening. Thymol increased ryanodine bind...

  1. Depolarization-stimulated 42K+ efflux in rat aorta is calcium- and cellular volume-dependent

    International Nuclear Information System (INIS)

    Magliola, L.; Jones, A.W.


    The purpose of this study was to investigate the factors controlling membrane permeability to potassium of smooth muscle cells from rat aorta stimulated by depolarization. The increase 42 K+ efflux (change in the rate constant) induced by depolarization (application of high concentrations of potassium chloride) was inhibited significantly by the calcium antagonists diltiazem and nisoldipine. Parallel inhibitory effects on contraction were observed. Diltiazem also inhibited potassium-stimulated 36 Cl- efflux. The addition of 25-150 mM KCl to normal physiologic solution stimulated 42 K+ efflux in a concentration-dependent manner. Diltiazem suppressed potassium-stimulated 42 K+ efflux approximately 90% at 25 mM KCl and approximately 40% at 150 mM KCl. The ability of nisoldipine to inhibit 42 K+ efflux also diminished as the potassium chloride concentration was elevated. The component of efflux that was resistant to calcium antagonists probably resulted from a decrease in the electrochemical gradient for potassium. Cellular water did not change during potassium addition. Substitution of 80 and 150 mM KCl for sodium chloride produced cellular swelling and enhanced potassium-stimulated 42 K+ efflux compared with potassium chloride addition. The addition of sucrose to prevent cellular swelling reduced efflux response to potassium substitution toward that of potassium addition. A hypoosmolar physiologic solution produced an increase in the 42 K+ efflux and a contracture that were both prevented by the addition of sucrose. We concluded that the depolarization-mediated 42 K+ efflux has three components: one is calcium dependent; a second is dependent on cellular volume; and a third is resistant to inhibition by calcium antagonists

  2. Calcium Overload Accelerates Phosphate-Induced Vascular Calcification Via Pit-1, but not the Calcium-Sensing Receptor. (United States)

    Masumoto, Asuka; Sonou, Tomohiro; Ohya, Masaki; Yashiro, Mitsuru; Nakashima, Yuri; Okuda, Kouji; Iwashita, Yuko; Mima, Toru; Negi, Shigeo; Shigematsu, Takashi


    Vascular calcification (VC) is a risk factor of cardiovascular and all-cause mortality in patients with chronic kidney disease (CKD). CKD-mineral and bone metabolism disorder is an important problem in patients with renal failure. Abnormal levels of serum phosphate and calcium affect CKD-mineral and bone metabolism disorder and contribute to bone disease, VC, and cardiovascular disease. Hypercalcemia is a contributing factor in progression of VC in patients with CKD. However, the mechanisms of how calcium promotes intracellular calcification are still unclear. This study aimed to examine the mechanisms underlying calcium-induced calcification in a rat aortic tissue culture model. Aortic segments from 7-week-old male Sprague-Dawley rats were cultured in serum-supplemented medium for 10 days. We added high calcium (HiCa; calcium 3.0 mM) to high phosphate (HPi; phosphate 3.8 mM) medium to accelerate phosphate and calcium-induced VC. We used phosphonoformic acid and the calcimimetic R-568 to determine whether the mechanism of calcification involves Pit-1 or the calcium-sensing receptor. Medial VC was significantly augmented by HPi+HiCa medium compared with HPi alone (300%, p<0.05), and was associated with upregulation of Pit-1 protein. Pit-1 protein concentrations in HPi+HiCa medium were greater than those in HPi medium. Phosphonoformic acid completely negated the augmentation of medial VC induced by HPi+HiCa. R-568 had no additive direct effect on medial VC. These results indicated that exposure to HPi+HiCa accelerates medial VC, and this is mediated through Pit-1, not the calcium-sensing receptor.

  3. 21 CFR 182.3225 - Calcium sorbate. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium sorbate. 182.3225 Section 182.3225 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3225 Calcium sorbate. (a) Product. Calcium sorbate. (b) Conditions of use. This substance is generally recognized as...

  4. 21 CFR 582.6185 - Calcium acetate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium acetate. 582.6185 Section 582.6185 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium acetate. (a) Product. Calcium acetate. (b) Conditions of use. This substance is generally...

  5. 21 CFR 582.3225 - Calcium sorbate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium sorbate. 582.3225 Section 582.3225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL....3225 Calcium sorbate. (a) Product. Calcium sorbate. (b) Conditions of use. This substance is generally...

  6. 21 CFR 582.6195 - Calcium citrate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium citrate. 582.6195 Section 582.6195 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This substance is generally...

  7. 21 CFR 582.6219 - Calcium phytate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phytate. 582.6219 Section 582.6219 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium phytate. (a) Product. Calcium phytate. (b) Conditions of use. This substance is generally...

  8. 21 CFR 582.7187 - Calcium alginate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium alginate. 582.7187 Section 582.7187 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium alginate. (a) Product. Calcium alginate. (b) Conditions of use. This substance is generally...

  9. 21 CFR 582.2227 - Calcium silicate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 582.2227 Section 582.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium silicate. (a) Product. Calcium silicate. (b) Tolerance. 2 percent and 5 percent. (c) Limitations...

  10. Mechanism of store-operated calcium entry

    Indian Academy of Sciences (India)

    Activation of receptors coupled to the phospholipase C/IP3 signalling pathway results in a rapid release of calcium from its intracellular stores, eventually leading to depletion of these stores. Calcium store depletion triggers an influx of extracellular calcium across the plasma membrane, a mechanism known as the ...

  11. 21 CFR 582.6193 - Calcium chloride. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium chloride. 582.6193 Section 582.6193 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium chloride. (a) Product. Calcium chloride. (b) Conditions of use. This substance is generally...

  12. Genome-wide analysis of wheat calcium ATPases and potential role of selected ACAs and ECAs in calcium stress. (United States)

    Aslam, Roohi; Williams, Lorraine E; Bhatti, Muhammad Faraz; Virk, Nasar


    P 2 - type calcium ATPases (ACAs-auto inhibited calcium ATPases and ECAs-endoplasmic reticulum calcium ATPases) belong to the P- type ATPase family of active membrane transporters and are significantly involved in maintaining accurate levels of Ca 2+ , Mn 2+ and Zn 2+ in the cytosol as well as playing a very important role in stress signaling, stomatal opening and closing and pollen tube growth. Here we report the identification and possible role of some of these ATPases from wheat. In this study, ACA and ECA sequences of six species (belonging to Poaceae) were retrieved from different databases and a phylogenetic tree was constructed. A high degree of evolutionary relatedness was observed among P 2 sequences characterized in this study. Members of the respective groups from different plant species were observed to fall under the same clade. This pattern highlights the common ancestry of P 2- type calcium ATPases. Furthermore, qRT-PCR was used to analyse the expression of selected ACAs and ECAs from Triticum aestivum (wheat) under calcium toxicity and calcium deficiency. The data indicated that expression of ECAs is enhanced under calcium stress, suggesting possible roles of these ATPases in calcium homeostasis in wheat. Similarly, the expression of ACAs was significantly different in plants grown under calcium stress as compared to plants grown under control conditions. This gives clues to the role of ACAs in signal transduction during calcium stress in wheat. Here we concluded that wheat genome consists of nine P 2B and three P 2A -type calcium ATPases. Moreover, gene loss events in wheat ancestors lead to the loss of a particular homoeolog of a gene in wheat. To elaborate the role of these wheat ATPases, qRT-PCR was performed. The results indicated that when plants are exposed to calcium stress, both P 2A and P 2B gene expression get enhanced. This further gives clues about the possible role of these ATPases in wheat in calcium management. These findings can be

  13. Medical uses of radioactive calcium. Review of an IAEA programme to promote the applications of calcium-47

    International Nuclear Information System (INIS)


    Calcium plays a number of biologically essential roles, which have long been under investigation by various techniques available to medical science. One of the most important of these techniques is radioactive tracer analysis, i. e. study of the functions of calcium within the body with the help of a radioactive isotope of the element. The calcium-47 programme of the International Atomic Energy Agency is intended to promote these investigations by facilitating the production and use of this isotope. The importance attached to calcium- 47 is due to the special properties of this isotope, which make it the most valuable tool for many calcium studies by the radioactive tracer method. The Agency has for four years been engaged in a comprehensive effort to bring calcium- 47 into routine medical use. To this end, it has surveyed the need for this isotope, stimulated its cheaper production, encouraged the investigation of its medical possibilities, and arranged for the dissemination of the information thus obtained. The fact that calcium-47 is no longer considered an exotic isotope is at least partly due to the Agency's efforts, in co-operation with interested scientists throughout the world

  14. A microstructural study of the degradation and calcium release from hydroxyapatite-calcium oxide ceramics made by infiltration. (United States)

    Zhang, Qinghao; Schmelzer, Eva; Gerlach, Jörg C; Nettleship, Ian


    Hydroxyapatite pellets, partially densified in a low-temperature heat treatment, were infiltrated with calcium nitrate solution followed by in-situ precipitation of Ca(OH) 2 and CaCO 3 . The infiltrated bodies were then densified to high relative density and the calcium carbonate transformed to calcium oxide during sintering and resulted in biphasic hydroxyapatite-CaO ceramics. This work investigated the influence of the infiltration on surface morphology, weight change, and microstructural-level degradation caused by exposure to saline at pH=7.4 and a temperature of 20°C. The CaO rendered the materials more susceptible to degradation, and released calcium into the saline faster than single phase, calcium deficient hydroxyapatite (HA) that were used as a control. In consequence, these ceramics could be used to release calcium into the culture microenvironments of bone tissue or bone marrow cells next to a scaffold surface. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Effect of exhausting exercise and calcium supplementation on potassium, magnesium, copper, zinc and calcium levels in athletes

    International Nuclear Information System (INIS)

    Cinar, V.; Baltaci, A.K.; Mogulkoc, R.


    Present study was performed to determine four week calcium supplementation and athleticism exercise on plasma potassium, calcium, magnesium, cupper and zinc levels in resting and exhaustion. Research was carried out on 30 healthy male people. Group 1; Exercise, Group 2; Exercise + Calcium supplementation, Group 3; Sedentary + Calcium supplemented. All elements levels increased by exhausting exercise (P<0.05). Plasma K and Ca levels increased in exercise group after supplementation (P<0.05). Ca levels increased in exercise + supplemented group (P<0.05). This increase was much more in group three (P<0.05). Plasma Cu levels increased by Ca supplementation in sedentary (P<0.05). Exhausting exercise increased Zn levels in sedentary after supplementation (P<0.05). The results of present study show that calcium supplementation for 4 week does not have clear affect on potassium and Mg. However, calcium levels were increased by supplementation and Cu after the supplementation. It was also exhausting exercise that caused increase in all parameters. (author)

  16. 21 CFR 582.5230 - Calcium sulfate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium sulfate. 582.5230 Section 582.5230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b) Conditions of use. This substance...

  17. 21 CFR 582.5195 - Calcium citrate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium citrate. 582.5195 Section 582.5195 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5195 Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This substance...

  18. 21 CFR 582.1207 - Calcium lactate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium lactate. 582.1207 Section 582.1207 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1207 Calcium lactate. (a) Product. Calcium lactate. (b) Conditions of use. This substance is...

  19. 21 CFR 182.2227 - Calcium silicate. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 182.2227 Section 182.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Calcium silicate. (a) Product. Calcium silicate. (b) Tolerance. 2 percent and 5 percent. (c) Limitations...

  20. 21 CFR 582.1195 - Calcium citrate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium citrate. 582.1195 Section 582.1195 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1195 Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This substance is...

  1. 21 CFR 582.1210 - Calcium oxide. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium oxide. 582.1210 Section 582.1210 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1210 Calcium oxide. (a) Product. Calcium oxide. (b) Conditions of use. This substance is generally...

  2. 21 CFR 582.1193 - Calcium chloride. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium chloride. 582.1193 Section 582.1193 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1193 Calcium chloride. (a) Product. Calcium chloride. (b) Conditions of use. This substance...

  3. Novel Peptide with Specific Calcium-Binding Capacity from Schizochytrium sp. Protein Hydrolysates and Calcium Bioavailability in Caco-2 Cells

    Directory of Open Access Journals (Sweden)

    Xixi Cai


    Full Text Available Peptide-calcium can probably be a suitable supplement to improve calcium absorption in the human body. In this study, a specific peptide Phe-Tyr (FY with calcium-binding capacity was purified from Schizochytrium sp. protein hydrolysates through gel filtration chromatography and reversed phase HPLC. The calcium-binding capacity of FY reached 128.77 ± 2.57 μg/mg. Results of ultraviolet spectroscopy, fluorescence spectroscopy, and infrared spectroscopy showed that carboxyl groups, amino groups, and amido groups were the major chelating sites. FY-Ca exhibited excellent thermal stability and solubility, which were beneficial to be absorbed and transported in the basic intestinal tract of the human body. Moreover, the calcium bioavailability in Caco-2 cells showed that FY-Ca could enhance calcium uptake efficiency by more than three times when compared with CaCl2, and protect calcium ions against dietary inhibitors, such as tannic acid, oxalate, phytate, and Zn2+. Our findings further the progress of algae-based peptide-calcium, suggesting that FY-Ca has the potential to be developed as functionally nutraceutical additives.

  4. How calcium makes endocytic receptors attractive

    DEFF Research Database (Denmark)

    Andersen, Christian B F; Moestrup, Søren K


    of the receptor. Endosomal acidification and calcium efflux lead to the essential ligand-receptor affinity switch and separation. Recent data, including crystal structures of receptor-ligand complexes, now reveal how calcium, in different types of domain scaffolds, functions in a common way as a removable...... 'lynchpin' that stabilizes favorable positioning of ligand-attractive receptor residues. In addition to explaining how calcium depletion can cause ligand-receptor dissociation, the new data add further insight into how acidification contributes to dissociation through structural changes that affect...... the receptor calcium sites....

  5. The increasing of enamel calcium level after casein phosphopeptideamorphous calcium phosphate covering

    Directory of Open Access Journals (Sweden)

    Widyasri Prananingrum


    Full Text Available Background: Caries process is characterized by the presence of demineralization. Demineralization is caused by organic acids as a result of carbohydrate substrate fermentation. Remineralization is a natural repair process for non-cavitated lesions. Remineralization occurs if there are Ca2+ and PO43- ions in sufficient quantities. Casein-amorphous calcium phosphate phosphopeptide (CPP-ACP is a paste material containing milk protein (casein, that actually contains minerals, such as calcium and phosphate. The casein ability to stabilize calcium phosphate and enhance mineral solubility and bioavailability confers upon CPP potential to be biological delivery vehicles for calcium and phosphate. Purpose: The aim of this study was to determine the calcium levels in tooth enamel after being covered with CPP-ACP 2 times a day for 3, 14 and 28 days. Methods: Sample were bovine incisors of 3 year old cows divided into 4 groups, namely group I as control group, group II, III and IV as treatment groups covered with CPP-ACP 2 times a day. All of those teeth were then immersed in artificial saliva. Group II was immersed for 3 days, while group III was immersed for 14 days, and group IV was immersed for 28 days. One drop of CPP-ACP was used to cover the entire labial surface of teeth. The measurement of the calcium levels was then conducted by using titration method. All data were analyzed by One- Way ANOVA test with 5% degree of confidence. Results: The results showed significant difference of the calcium levels in tooth enamel of those groups after covered with CPP-ACP 2 times a day for 3, 14 and 28 days (p = 0.001. There is also significant difference of the calcium levels in tooth enamel of those treatment groups and the control group (p = 0.001. Conclusion: The calcium levels of tooth enamel are increased after covered with CPP-ACP 2 times a day for 3, 14 and 28 days.Latar belakang: Proses terjadinya karies gigi ditandai oleh adanya demineralisasi

  6. Transgenic plants with increased calcium stores (United States)

    Wyatt, Sarah (Inventor); Tsou, Pei-Lan (Inventor); Robertson, Dominique (Inventor); Boss, Wendy (Inventor)


    The present invention provides transgenic plants over-expressing a transgene encoding a calcium-binding protein or peptide (CaBP). Preferably, the CaBP is a calcium storage protein and over-expression thereof does not have undue adverse effects on calcium homeostasis or biochemical pathways that are regulated by calcium. In preferred embodiments, the CaBP is calreticulin (CRT) or calsequestrin. In more preferred embodiments, the CaBP is the C-domain of CRT, a fragment of the C-domain, or multimers of the foregoing. In other preferred embodiments, the CaBP is localized to the endoplasmic reticulum by operatively associating the transgene encoding the CaBP with an endoplasmic reticulum localization peptide. Alternatively, the CaBP is targeted to any other sub-cellular compartment that permits the calcium to be stored in a form that is biologically available to the plant. Also provided are methods of producing plants with desirable phenotypic traits by transformation of the plant with a transgene encoding a CaBP. Such phenotypic traits include increased calcium storage, enhanced resistance to calcium-limiting conditions, enhanced growth and viability, increased disease and stress resistance, enhanced flower and fruit production, reduced senescence, and a decreased need for fertilizer production. Further provided are plants with enhanced nutritional value as human food or animal feed.

  7. 21 CFR 582.5210 - Calcium oxide. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium oxide. 582.5210 Section 582.5210 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5210 Calcium oxide. (a) Product. Calcium oxide. (b) Conditions of use. This substance is...

  8. Calcium Orthophosphate Cements and Concretes

    Directory of Open Access Journals (Sweden)

    Sergey V. Dorozhkin


    Full Text Available In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are a bioactive and biodegradable grafting material in the form of a powder and a liquid. Both phases form after mixing a viscous paste that after being implanted, sets and hardens within the body as either a non-stoichiometric calcium deficient hydroxyapatite (CDHA or brushite, sometimes blended with unreacted particles and other phases. As both CDHA and brushite are remarkably biocompartible and bioresorbable (therefore, in vivo they can be replaced with newly forming bone, calcium orthophosphate cements represent a good correction technique for non-weight-bearing bone fractures or defects and appear to be very promising materials for bone grafting applications. Besides, these cements possess an excellent osteoconductivity, molding capabilities and easy manipulation. Furthermore, reinforced cement formulations are available, which in a certain sense might be described as calcium orthophosphate concretes. The concepts established by calcium orthophosphate cement pioneers in the early 1980s were used as a platform to initiate a new generation of bone substitute materials for commercialization. Since then, advances have been made in the composition, performance and manufacturing; several beneficial formulations have already been introduced as a result. Many other compositions are in experimental stages. In this review, an insight into calcium orthophosphate cements and concretes, as excellent biomaterials suitable for both dental and bone grafting application, has been provided.

  9. Discrete-State Stochastic Models of Calcium-Regulated Calcium Influx and Subspace Dynamics Are Not Well-Approximated by ODEs That Neglect Concentration Fluctuations (United States)

    Weinberg, Seth H.; Smith, Gregory D.


    Cardiac myocyte calcium signaling is often modeled using deterministic ordinary differential equations (ODEs) and mass-action kinetics. However, spatially restricted “domains” associated with calcium influx are small enough (e.g., 10−17 liters) that local signaling may involve 1–100 calcium ions. Is it appropriate to model the dynamics of subspace calcium using deterministic ODEs or, alternatively, do we require stochastic descriptions that account for the fundamentally discrete nature of these local calcium signals? To address this question, we constructed a minimal Markov model of a calcium-regulated calcium channel and associated subspace. We compared the expected value of fluctuating subspace calcium concentration (a result that accounts for the small subspace volume) with the corresponding deterministic model (an approximation that assumes large system size). When subspace calcium did not regulate calcium influx, the deterministic and stochastic descriptions agreed. However, when calcium binding altered channel activity in the model, the continuous deterministic description often deviated significantly from the discrete stochastic model, unless the subspace volume is unrealistically large and/or the kinetics of the calcium binding are sufficiently fast. This principle was also demonstrated using a physiologically realistic model of calmodulin regulation of L-type calcium channels introduced by Yue and coworkers. PMID:23509597

  10. Voltage-gated calcium flux mediates Escherichia coli mechanosensation. (United States)

    Bruni, Giancarlo N; Weekley, R Andrew; Dodd, Benjamin J T; Kralj, Joel M


    Electrically excitable cells harness voltage-coupled calcium influx to transmit intracellular signals, typically studied in neurons and cardiomyocytes. Despite intense study in higher organisms, investigations of voltage and calcium signaling in bacteria have lagged due to their small size and a lack of sensitive tools. Only recently were bacteria shown to modulate their membrane potential on the timescale of seconds, and little is known about the downstream effects from this modulation. In this paper, we report on the effects of electrophysiology in individual bacteria. A genetically encoded calcium sensor expressed in Escherichia coli revealed calcium transients in single cells. A fusion sensor that simultaneously reports voltage and calcium indicated that calcium influx is induced by voltage depolarizations, similar to metazoan action potentials. Cytoplasmic calcium levels and transients increased upon mechanical stimulation with a hydrogel, and single cells altered protein concentrations dependent on the mechanical environment. Blocking voltage and calcium flux altered mechanically induced changes in protein concentration, while inducing calcium flux reproduced these changes. Thus, voltage and calcium relay a bacterial sense of touch and alter cellular lifestyle. Although the calcium effectors remain unknown, these data open a host of new questions about E. coli , including the identity of the underlying molecular players, as well as other signals conveyed by voltage and calcium. These data also provide evidence that dynamic voltage and calcium exists as a signaling modality in the oldest domain of life, and therefore studying electrophysiology beyond canonical electrically excitable cells could yield exciting new findings.

  11. Diffusion of calcium in pure and doped NaCl; Diffusion du calcium dans NaCl pur et dope

    Energy Technology Data Exchange (ETDEWEB)

    Slifkin, L; Brebec, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires


    We have determined, by diffusion experiments of Ca in pure and doped NaCl, the activation energy for the calcium jumps and the binding energy between calcium ion and vacancy. (authors) [French] Nous avons determine, par des mesures de diffusion du Ca dans NaCl pur et NaCl dope avec CaCl{sub 2}, l'energie d'activation relative aux sauts du calcium et l'energie de liaison lacune-calcium. (auteurs)

  12. Calcium and cargoes as regulators of myosin 5a activity

    International Nuclear Information System (INIS)

    Sellers, James R.; Thirumurugan, Kavitha; Sakamoto, Takeshi; Hammer, John A.; Knight, Peter J.


    Myosin 5a is a two-headed actin-dependent motor that transports various cargoes in cells. Its enzymology and mechanochemistry have been extensively studied in vitro. It is a processive motor that takes multiple 36 nm steps on actin. The enzymatic activity of myosin 5 is regulated by an intramolecular folding mechanism whereby its lever arms fold back against the coiled-coil tail such that the motor domains directly bind the globular tail domains. We show that the structure seen in individual folded molecules is consistent with electron density map of two-dimensional crystals of the molecule. In this compact state, the actin-activated MgATPase activity of the molecule is markedly inhibited and the molecule cannot move processively on surface bound actin filaments. The actin-activated MgATPase activity of myosin 5a is activated by increasing the calcium concentration or by binding of a cargo-receptor molecule, melanophilin, in vitro. However, calcium binding to the calmodulin light chains results in dissociation of some of the calmodulin which disrupts the ability of myosin 5a to move on actin filaments in vitro. Thus we propose that the physiologically relevant activation pathway in vivo involves binding of cargo-receptor proteins

  13. 21 CFR 201.70 - Calcium labeling. (United States)


    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Calcium labeling. 201.70 Section 201.70 Food and... LABELING Labeling Requirements for Over-the-Counter Drugs § 201.70 Calcium labeling. (a) The labeling of over-the-counter (OTC) drug products intended for oral ingestion shall contain the calcium content per...

  14. Calcium supplementation in osteoporosis: useful or harmful? (United States)

    Chiodini, Iacopo; Bolland, Mark J


    Osteoporosis and fragility fractures are important social and economic problems worldwide and are due to both the loss of bone mineral density and sarcopenia. Indeed, fragility fractures are associated with increased disability, morbidity and mortality. It is known that a normal calcium balance together with a normal vitamin D status is important for maintaining well-balanced bone metabolism, and for many years, calcium and vitamin D have been considered crucial in the prevention and treatment of osteoporosis. However, recently, the usefulness of calcium supplementation (alone or with concomitant vitamin D) has been questioned, since some studies reported only weak efficacy of these supplementations in reducing fragility fracture risk. On the other hand, besides the gastrointestinal side effects of calcium supplements and the risk of kidney stones related to use of co-administered calcium and vitamin D supplements, other recent data suggested potential adverse cardiovascular effects from calcium supplementation. This debate article is focused on the evidence regarding both the possible usefulness for bone health and the potential harmful effects of calcium and/or calcium with vitamin D supplementation. © 2018 European Society of Endocrinology.

  15. A sensor for calcium uptake (United States)

    Collins, Sean; Meyer, Tobias


    Mitochondria — the cell’s power plants — increase their energy production in response to calcium signals in the cytoplasm. A regulator of the elusive mitochondrial calcium channel has now been identified. PMID:20844529

  16. Children's Bone Health and Calcium (United States)

    ... Twitter Pinterest Email Print Children's Bone Health and Calcium: Condition Information What is bone health and how ... straight, walk, run, and lead an active life. Calcium is one of the key dietary building blocks ...

  17. Role of polyhydroxybutyrate in mitochondrial calcium uptake (United States)

    Smithen, Matthew; Elustondo, Pia A.; Winkfein, Robert; Zakharian, Eleonora; Abramov, Andrey Y.; Pavlov, Evgeny


    Polyhydroxybutyrate (PHB) is a biological polymer which belongs to the class of polyesters and is ubiquitously present in all living organisms. Mammalian mitochondrial membranes contain PHB consisting of up to 120 hydroxybutyrate residues. Roles played by PHB in mammalian mitochondria remain obscure. It was previously demonstrated that PHB of the size similar to one found in mitochondria mediates calcium transport in lipid bilayer membranes. We hypothesized that the presence of PHB in mitochondrial membrane might play a significant role in mitochondrial calcium transport. To test this, we investigated how the induction of PHB hydrolysis affects mitochondrial calcium transport. Mitochondrial PHB was altered enzymatically by targeted expression of bacterial PHB hydrolyzing enzyme (PhaZ7) in mitochondria of mammalian cultured cells. The expression of PhaZ7 induced changes in mitochondrial metabolism resulting in decreased mitochondrial membrane potential in HepG2 but not in U87 and HeLa cells. Furthermore, it significantly inhibited mitochondrial calcium uptake in intact HepG2, U87 and HeLa cells stimulated by the ATP or by the application of increased concentrations of calcium to the digitonin permeabilized cells. Calcium uptake in PhaZ7 expressing cells was restored by mimicking calcium uniporter properties with natural electrogenic calcium ionophore - ferutinin. We propose that PHB is a previously unrecognized important component of the mitochondrial calcium uptake system. PMID:23702223

  18. Trace mineral interactions during elevated calcium consumption

    International Nuclear Information System (INIS)

    Smith, K.T.; Luhrsen, K.R.


    Elevated calcium consumption is reported to affect trace mineral bioavailability. The authors examined this phenomenon in both single dose radio-label test meals and an eight week feeding trial in rats. In the single dose studies, human milk, cows milk, and various calcium sources were examined in relation to radio-iron and radio-zinc retention. 59 Fe retention was greater from human milk than cows milk. However, when the calcium content of human milk was adjusted (with CaHPO 4 or CaCO 3 ) to equal the level in cows milk, iron retention was depressed. Similarly, when calcium sources (CaCO 3 , CaHPO 4 , hydroxy-apatite, bone meal) were examined at different calcium:metal molar ratios, the degree of inhibition on metal retention varied. In general, phosphate salts were more inhibiting than carbonates. In the feeding trial, calcium was fed in diets at normal (0.5%) or elevated (1.5%) levels. Serum, liver, kidney, and bone trace mineral profiles were obtained. In general, most trace elements showed decreased levels in the tissues. Zinc and iron were most striking, followed by magnesium with minor changes in copper. A high calcium:high mineral supplemented group was also fed. Mixed mineral supplementation prevented all calcium interactions. These data indicate the importance of calcium mineral interactions in bioavailability considerations in both milk sources and in mineral supplementation

  19. Oxalic acid decreases calcium absorption in rats

    International Nuclear Information System (INIS)

    Weaver, C.M.; Martin, B.R.; Ebner, J.S.; Krueger, C.A.


    Calcium absorption from salts and foods intrinsically labeled with 45 Ca was determined in the rat model. Calcium bioavailability was nearly 10 times greater for low oxalate kale, CaCO 3 and CaCl 2 than from CaC 2 O 4 (calcium oxalate) and spinach (high in oxalates). Extrinsic and intrinsic labeling techniques gave a similar assessment of calcium bioavailability from kale but not from spinach

  20. Preparation and properties of calcium zirconate

    International Nuclear Information System (INIS)

    Dudek, M.; Bucko, M.; Rog, G.


    Dense samples of calcium zirconate were prepared. Electrical conductivity of the samples were measured in the temperature range 873 - 1273 K by both the d.c. four probe and the impedance spectroscopy methods. Calcium zirconate with small excess of calcium oxide appeared to be oxygen ion conductor. It was applied as an electrolyte in solid-state galvanic cells. (author)

  1. Calcium Supplements: Do Men Need Them Too? (United States)

    ... Lifestyle Nutrition and healthy eating Should men take calcium supplements? Answers from Katherine Zeratsky, R.D., L. ... Most healthy men don't need to take calcium supplements. Calcium is important for men for optimal ...

  2. The effect of brushing with nano calcium carbonate and calcium carbonate toothpaste on the surface roughness of nano-ionomer (United States)

    Anisja, D. H.; Indrani, D. J.; Herda, E.


    Nanotechnology developments in dentistry have resulted in the development of nano-ionomer, a new restorative material. The surface roughness of restorative materials can increase bacteria adhesion and lead to poor oral hygiene. Abrasive agents in toothpaste can alter tooth and restorative material surfaces. The aim of this study is to identify the effect of brushing with nano calcium carbonate, and calcium carbonate toothpaste on surface roughness of nano-ionomer. Eighteen nano-ionomer specimens were brushed with Aquabidest (doubledistilled water), nano calcium carbonate and calcium carbonate toothpaste. Brushing lasted 30 minutes, and the roughness value (Ra) was measured after each 10 minute segment using a surface roughness tester. The data was analyzed using repeated ANOVA and one-way ANOVA test. The value of nano-ionomer surface roughness increased significantly (p<0.05) after 20 minutes of brushing with the nano calcium carbonate toothpaste. Brushing with calcium carbonate toothpaste leaves nano-ionomer surfaces more rugged than brushing with nano calcium carbonate toothpaste.

  3. Regulation of cardiomyocyte autophagy by calcium. (United States)

    Shaikh, Soni; Troncoso, Rodrigo; Criollo, Alfredo; Bravo-Sagua, Roberto; García, Lorena; Morselli, Eugenia; Cifuentes, Mariana; Quest, Andrew F G; Hill, Joseph A; Lavandero, Sergio


    Calcium signaling plays a crucial role in a multitude of events within the cardiomyocyte, including cell cycle control, growth, apoptosis, and autophagy. With respect to calcium-dependent regulation of autophagy, ion channels and exchangers, receptors, and intracellular mediators play fundamental roles. In this review, we discuss calcium-dependent regulation of cardiomyocyte autophagy, a lysosomal mechanism that is often cytoprotective, serving to defend against disease-related stress and nutrient insufficiency. We also highlight the importance of the subcellular distribution of calcium and related proteins, interorganelle communication, and other key signaling events that govern cardiomyocyte autophagy. Copyright © 2016 the American Physiological Society.

  4. Diuretics and disorders of calcium homeostasis. (United States)

    Grieff, Marvin; Bushinsky, David A


    Diuretics commonly are administered in disorders of sodium balance. Loop diuretics inhibit the Na-K-2Cl transporter and also increase calcium excretion. They are often used in the treatment of hypercalcemia. Thiazide diuretics block the thiazide-sensitive NaCl transporter in the distal convoluted tubule, and can decrease calcium excretion. They are often used in the treatment of nephrolithiasis. Carbonic anhydrase inhibitors decrease bicarbonate absorption and the resultant metabolic acidosis can increase calcium excretion. Their use can promote nephrocalcinosis and nephrolithiasis. This review will address the use of diuretics on disorders of calcium homeostasis. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. Chapter 15. Measurement of the main calcium metabolism processes

    International Nuclear Information System (INIS)

    Milhaud, G.


    A method of measuring the chief calcium metabolism processes in man is described and is based on the following techniques and theory: intraveinous injection of 45 Ca; determination of the specific radioactivity of serum calcium, total radioactivity of urine and stools, ingested and excreted calcium; mathematical analysis of the specific radioactivity decay curve for serum calcium. The following data were obtained in this way: intestinal absorption fraction of calcium in the chemical state in which it is found in foods; quantity of calcium excreted by the intestin, as distinct from the non-absorbed fraction; physiological turnover rates in the skeleton by osteolysis and osteoblastosis; mass of rapidly exchangeable calcium in the organism, i.e. the calcium pool; rates of exchange with serum calcium of calcium from the different pool components, mass of bone calcium subjected to recrystallisation. Some applications of the method in man and the verification of the theory in rats are reported [fr

  6. Calcium phosphates: what is the evidence? (United States)

    Larsson, Sune


    A number of different calcium phosphate compounds such as calcium phosphate cements and solid beta-tricalcium phosphate products have been introduced during the last decade. The chemical composition mimics the mineral phase of bone and as a result of this likeness, the materials seem to be remodeled as for normal bone through a cell-mediated process that involves osteoclastic activity. This is a major difference when compared with, for instance, calcium sulphate compounds that after implantation dissolve irrespective of the new bone formation rate. Calcium phosphates are highly biocompatible and in addition, they act as synthetic osteoconductive scaffolds after implantation in bone. When placed adjacent to bone, osteoid is formed directly on the surface of the calcium phosphate with no soft tissue interposed. Remodeling is slow and incomplete, but by adding more and larger pores, like in ultraporous beta-tricalcium phosphate, complete or nearly complete resorption can be achieved. The indications explored so far include filling of metaphyseal fracture voids or bone cysts, a volume expander in conjunction with inductive products, and as a carrier for various growth factors and antibiotics. Calcium phosphate compounds such as calcium phosphate cement and beta-tricalcium phosphate will most certainly be part of the future armamentarium when dealing with fracture treatment. It is reasonable to believe that we have so far only seen the beginning when it comes to clinical applications.

  7. Interaction of bovine gallbladder mucin and calcium-binding protein: effects on calcium phosphate precipitation

    NARCIS (Netherlands)

    Afdhal, N. H.; Ostrow, J. D.; Koehler, R.; Niu, N.; Groen, A. K.; Veis, A.; Nunes, D. P.; Offner, G. D.


    Gallstones consist of calcium salts and cholesterol crystals, arrayed on a matrix of gallbladder mucin (GBM), and regulatory proteins like calcium-binding protein (CBP). To determine if interactions between CBP and GBM follow a biomineralization scheme, their mutual binding and effects on CaHPO4

  8. The calcium oxide influence on formation of manganese, calcium pyrovanadate solid solutions

    International Nuclear Information System (INIS)

    Vatolin, N.A.; Volkova, P.I.; Sapozhnikova, T.V.; Ovchinnikova, L.A.


    The X-ray graphic, derivatographic, microscopic and chemical methods are used to study solid solutions of manganese, calcium pyrovanadates containing 1-10 mass% CaO and the products of interaction of reprocessing charges of vanadium-containing converter slags intended for he formation of manganese and calcium pyrovanadates with additions of calcium oxide within 10-90 mass%. It is established that in the case of 1-6 mass% CaO content in manganese pyrovanadate solid interstitial solutions appear, while at 6-20 mass% CaO - solid substitution solutions form. The results of calculating elementary cell parameters as well as melting temperatures and pyrovanadate solid solution solubility depending on CaO content are presented. The best solubility of introduction solid solutions during vanadium extraction according to the lime technology is found

  9. Glass-water interphase reactivity with calcium rich solutions

    International Nuclear Information System (INIS)

    Chave, T.; Frugier, P.; Gin, S.; Chave, T.; Ayral, A.


    The effect of calcium on synthetic glass alteration mechanisms has been studied. It is known that the higher the calcium content in the glass, the higher the forward rate. However, in a confined medium reaching apparent saturation state and a pH (90 degrees C) around 9, synthetic calcium-bearing glasses are those with the lowest alteration rates. This work brings new and fundamental evidence toward understanding the alteration mechanisms: the rate-decreasing effect of calcium exists even if the calcium comes from the solution. Calcium from solution reacts with silica network in the hydrated layer at the glass surface. The calcium effect on the alteration kinetics is explained by the condensation of a passivating reactive interphase (PRI) whose passivating properties are strongly enhanced when calcium participates in its construction. These experiments provide new evidence of the role of condensation mechanisms in glass alteration. This better understanding of the calcium effect on glass long-term behavior will be useful both for improving glass formulations and for understanding the influence of the water composition. (authors)

  10. Calcium – how and why?

    Indian Academy of Sciences (India)


    biological processes because of its unusual physical and chemical properties. 1. History of calcium ... cellular roles of calcium has established the importance of this ion ..... Ca2+ ion, for example in regulating enzyme activity (Price. 1975 ...

  11. Bcl-2 overexpression: effects on transmembrane calcium movement

    International Nuclear Information System (INIS)

    Rangaswami, Arun A.; Premack, Brett; Walleczek, Jan; Killoran, Pamela; Gardner, Phyllis; Knox, Susan J.


    Purpose/Objective: High levels of expression of the proto-oncogene bcl-2 and its 26 kD protein product Bcl-2 have been correlated with the inhibition of apoptosis and the increased resistance of tumor cells to cytotoxic drugs and ionizing radiation. Unfortunately, the specific mechanism of action of Bcl-2 remains poorly understood. In the studies described here, the role of intracellular calcium fluxes and plasma membrane calcium cycling in the induction of apoptosis, and the effect of Bcl-2 expression on the modulation of transmembrane calcium fluxes following treatment of cells with cytotoxic agents were studied. The relationship between intracellular calcium release, capacitive calcium entry, and the plasma membrane potential were also investigated. Materials and Methods: Human B-cell lymphoma (PW) and human promyelocytic leukemia (HL60) cell lines were transfected with Bcl-2 and a control vector. The Bcl-2 transfectants over expressed the Bcl-2 onco-protein and were more resistant to irradiation than the control cells. Cells were loaded with fluorescent indicators indo-1 and fura-2 AM to quantify the cytosolic calcium concentration and subsequent calcium responses to a variety of cytotoxic stimuli, including the microsomal ATPase inhibitor, thapsigargin, using fluorometric measurements. Comparisons of resting and stimulated cytosolic calcium concentrations were made between the parental, neomycin control, and bcl-2 transfected cells. In order to determine the actual calcium influx rate, cells were loaded with either indo-1 or fura-2 and then exposed to 0.1 mM extracellular manganese, which enters the cells through calcium influx channels and quenches the fluorescent signal in proportion to the calcium influx rate. In order to determine the role of the membrane potential in driving calcium influx, cells were treated with either 0.1 μM Valinomycin or isotonic potassium chloride to either hyper polarize or depolarize the resting membrane potential, and the

  12. 21 CFR 184.1206 - Calcium iodate. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium iodate. 184.1206 Section 184.1206 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1206 Calcium iodate. (a) Calcium iodate [Ca(IO3)2·H2O, CAS Reg. No. 7789-80...

  13. The total synthesis of calcium atorvastatin. (United States)

    Dias, Luiz C; Vieira, Adriano S; Barreiro, Eliezer J


    A practical and convergent asymmetric route to calcium atorvastatin (1) is reported. The synthesis of calcium atorvastatin (1) was performed using the remote 1,5-anti asymmetric induction in the boron-mediated aldol reaction of β-alkoxy methylketone (4) with pyrrolic aldehyde (3) as a key step. Calcium atorvastatin was obtained from aldehyde (3) after 6 steps, with a 41% overall yield.

  14. Calcium dynamics in vascular smooth muscle


    Amberg, Gregory C.; Navedo, Manuel F.


    Smooth muscle cells are ultimately responsible for determining vascular luminal diameter and blood flow. Dynamic changes in intracellular calcium are a critical mechanism regulating vascular smooth muscle contractility. Processes influencing intracellular calcium are therefore important regulators of vascular function with physiological and pathophysiological consequences. In this review we discuss the major dynamic calcium signals identified and characterized in vascular smooth muscle cells....

  15. Stochastic Simulation of Cardiac Ventricular Myocyte Calcium Dynamics and Waves


    Tuan, Hoang-Trong Minh; Williams, George S. B.; Chikando, Aristide C.; Sobie, Eric A.; Lederer, W. Jonathan; Jafri, M. Saleet


    A three dimensional model of calcium dynamics in the rat ventricular myocyte was developed to study the mechanism of calcium homeostasis and pathological calcium dynamics during calcium overload. The model contains 20,000 calcium release units (CRUs) each containing 49 ryanodine receptors. The model simulates calcium sparks with a realistic spontaneous calcium spark rate. It suggests that in addition to the calcium spark-based leak, there is an invisible calcium leak caused by the stochastic ...

  16. Immobilization of calcium sulfate contained in demolition waste

    International Nuclear Information System (INIS)

    Ambroise, J.; Pera, J.


    This paper presents the results of a laboratory study undertaken to examine the treatment of demolition waste containing calcium sulfate by means of calcium sulfoaluminate clinker (CSA). The quantity of CSA necessary to entirely consume calcium sulfate was determined. Using infrared spectrometry analysis and X-ray diffraction, it was shown that calcium sulfate was entirely consumed when the ratio between CSA and calcium sulfate was 4. Standard sand was polluted by 4% calcium sulfate. Two solutions were investigated: ·either global treatment of sand by CSA, ·or immobilization of calcium sulfate by CSA, followed by the introduction of this milled mixture in standard sand. Regardless of the type of treatment, swelling was almost stabilized after 28 days of immersion in water

  17. Calcium intake and risk of fracture: systematic review. (United States)

    Bolland, Mark J; Leung, William; Tai, Vicky; Bastin, Sonja; Gamble, Greg D; Grey, Andrew; Reid, Ian R


    To examine the evidence underpinning recommendations to increase calcium intake through dietary sources or calcium supplements to prevent fractures. Systematic review of randomised controlled trials and observational studies of calcium intake with fracture as an endpoint. Results from trials were pooled with random effects meta-analyses. Ovid Medline, Embase, PubMed, and references from relevant systematic reviews. Initial searches undertaken in July 2013 and updated in September 2014. Randomised controlled trials or cohort studies of dietary calcium, milk or dairy intake, or calcium supplements (with or without vitamin D) with fracture as an outcome and participants aged >50. There were only two eligible randomised controlled trials of dietary sources of calcium (n=262), but 50 reports from 44 cohort studies of relations between dietary calcium (n=37), milk (n=14), or dairy intake (n=8) and fracture outcomes. For dietary calcium, most studies reported no association between calcium intake and fracture (14/22 for total, 17/21 for hip, 7/8 for vertebral, and 5/7 for forearm fracture). For milk (25/28) and dairy intake (11/13), most studies also reported no associations. In 26 randomised controlled trials, calcium supplements reduced the risk of total fracture (20 studies, n=58,573; relative risk 0.89, 95% confidence interval 0.81 to 0.96) and vertebral fracture (12 studies, n=48,967. 0.86, 0.74 to 1.00) but not hip (13 studies, n=56,648; 0.95, 0.76 to 1.18) or forearm fracture (eight studies, n=51,775; 0.96, 0.85 to 1.09). Funnel plot inspection and Egger's regression suggested bias toward calcium supplements in the published data. In randomised controlled trials at lowest risk of bias (four studies, n=44,505), there was no effect on risk of fracture at any site. Results were similar for trials of calcium monotherapy and co-administered calcium and vitamin D. Only one trial in frail elderly women in residential care with low dietary calcium intake and vitamin D

  18. Protein kinase C interaction with calcium: a phospholipid-dependent process.

    LENUS (Irish Health Repository)

    Bazzi, M D


    The calcium-binding properties of calcium- and phospholipid-dependent protein kinase C (PKC) were investigated by equilibrium dialysis in the presence and the absence of phospholipids. Calcium binding to PKC displayed striking and unexpected behavior; the free proteins bound virtually no calcium at intracellular calcium concentrations and bound limited calcium (about 1 mol\\/mol of PKC) at 200 microM calcium. However, in the presence of membranes containing acidic phospholipids, PKC bound at least eight calcium ions per protein. The presence of 1 microM phorbol dibutyrate (PDBu) in the dialysis buffer had little effect on these calcium-binding properties. Analysis of PKC-calcium binding by gel filtration under equilibrium conditions gave similar results; only membrane-associated PKC bound significant amounts of calcium. Consequently, PKC is a member of what may be a large group of proteins that bind calcium in a phospholipid-dependent manner. The calcium concentrations needed to induce PKC-membrane binding were similar to those needed for calcium binding (about 40 microM calcium at the midpoint). However, the calcium concentration required for PKC-membrane binding was strongly influenced by the phosphatidylserine composition of the membranes. Membranes with higher percentages of phosphatidylserine required lower concentrations of calcium. These properties suggested that the calcium sites may be generated at the interface between PKC and the membrane. Calcium may function as a bridge between PKC and phospholipids. These studies also suggested that calcium-dependent PKC-membrane binding and PKC function could be regulated by a number of factors in addition to calcium levels and diacylglycerol content of the membrane.

  19. L-Type Calcium Channels Modulation by Estradiol. (United States)

    Vega-Vela, Nelson E; Osorio, Daniel; Avila-Rodriguez, Marco; Gonzalez, Janneth; García-Segura, Luis Miguel; Echeverria, Valentina; Barreto, George E


    Voltage-gated calcium channels are key regulators of brain function, and their dysfunction has been associated with multiple conditions and neurodegenerative diseases because they couple membrane depolarization to the influx of calcium-and other processes such as gene expression-in excitable cells. L-type calcium channels, one of the three major classes and probably the best characterized of the voltage-gated calcium channels, act as an essential calcium binding proteins with a significant biological relevance. It is well known that estradiol can activate rapidly brain signaling pathways and modulatory/regulatory proteins through non-genomic (or non-transcriptional) mechanisms, which lead to an increase of intracellular calcium that activate multiple kinases and signaling cascades, in the same way as L-type calcium channels responses. In this context, estrogens-L-type calcium channels signaling raises intracellular calcium levels and activates the same signaling cascades in the brain probably through estrogen receptor-independent modulatory mechanisms. In this review, we discuss the available literature on this area, which seems to suggest that estradiol exerts dual effects/modulation on these channels in a concentration-dependent manner (as a potentiator of these channels in pM concentrations and as an inhibitor in nM concentrations). Indeed, estradiol may orchestrate multiple neurotrophic responses, which open a new avenue for the development of novel estrogen-based therapies to alleviate different neuropathologies. We also highlight that it is essential to determine through computational and/or experimental approaches the interaction between estradiol and L-type calcium channels to assist these developments, which is an interesting area of research that deserves a closer look in future biomedical research.

  20. Real-time Recording of Cytosolic Calcium Levels in Arabidopsis thaliana Cell Cultures during Parabolic Flights (United States)

    Neef, Maren; Ecke, Margret; Hampp, Rüdiger


    In plants, like in other organisms, calcium (Ca2+) is an important second messenger which participates in the conversion of environmental signals into molecular responses. There is increasing evidence, that sensing of changes in gravitation or reorientation of tissues is an example for such signaling cascades in which Ca2+ is involved. In order to determine g-dependent changes in the cytosolic calcium (Ca^{2+}_{ {cyt}}) concentration of plant cells, semisolid transgenic callus cell cultures of Arabidopsis thaliana (A.t.), expressing the calcium sensor YC3.6 (cameleon), were exposed to g-forces between 1.8 g and μ g during parabolic flights. Using such cells, intracellular calcium transients can be monitored by FRET in vivo and in real-time. Interestingly we observed a slight decrease of the Ca^{2+}_{ {cyt}} level during the hypergravity phases of a parabola but a significant increase of the Ca^{2+}_{ {cyt}} concentration during microgravity. Application of known Ca2+ inhibitors and antagonists yielded the following effects: nifedipine (Ca2+ channel blocker) showed no effect, whereas LaCl3, GdCl3 (both inhibitors of uptake at the plasma membrane), DPI (inhibitor of NADP oxidase), and DMSO (solvent) diminished the gravity-alteration-related Ca^{2+}_{ {cyt}} response. EGTA (binding of Ca2+) and eosin yellow (inhibitor of a plasma membrane-located Ca2+ pump) suppressed the respective Ca^{2+}_{ {cyt}} changes entirely. We thus conclude that the significant increase in Ca^{2+}_{ {cyt}} under microgravity is largely due to extracellular Ca2+ sources.

  1. Parents' Calcium Knowledge Is Associated with Parental Practices to Promote Calcium Intake among Parents of Early Adolescent Children (United States)

    Gunther, Carolyn W.; Rose, Angela M.; Bruhn, Christine; Cluskey, Mary; Reicks, Marla; Richards, Rickelle; Wong, Siew Sun; Boushey, Carol J.; Misner, Scottie; Olson, Beth


    The study reported here aimed to identify the relationship of parents' calcium knowledge with diet-related parental practices and determinants of calcium knowledge. A cross-sectional survey was conducted measuring parental practices, calcium knowledge, and demographics. A convenience sample of 599 racially/ethnically diverse parents of children…

  2. Depletion of intracellular calcium stores facilitates the influx of extracellular calcium in platelet derived growth factor stimulated A172 glioblastoma cells. (United States)

    Vereb, G; Szöllösi, J; Mátyus, L; Balázs, M; Hyun, W C; Feuerstein, B G


    Calcium signaling in non-excitable cells is the consequence of calcium release from intracellular stores, at times followed by entry of extracellular calcium through the plasma membrane. To study whether entry of calcium depends upon the level of saturation of intracellular stores, we measured calcium channel opening in the plasma membrane of single confluent A172 glioblastoma cells stimulated with platelet derived growth factor (PDGF) and/or bradykinin (BK). We monitored the entry of extracellular calcium by measuring manganese quenching of Indo-1 fluorescence. PDGF raised intracellular calcium concentration ([Ca2+]i) after a dose-dependent delay (tdel) and then opened calcium channels after a dose-independent delay (tch). At higher doses (> 3 nM), BK increased [Ca2+]i after a tdel approximately 0 s, and tch decreased inversely with both dose and peak [Ca2+]i. Experiments with thapsigargin (TG), BK, and PDGF indicated that BK and PDGF share intracellular Ca2+ pools that are sensitive to TG. When these stores were depleted by treatment with BK and intracellular BAPTA, tdel did not change, but tch fell to almost 0 s in PDGF stimulated cells, indicating that depletion of calcium stores affects calcium channel opening in the plasma membrane. Our data support the capacitative model for calcium channel opening and the steady-state model describing quantal Ca2+ release from intracellular stores.

  3. Calcium supplementation and cardiovascular risk: A rising concern. (United States)

    Tankeu, Aurel T; Ndip Agbor, Valirie; Noubiap, Jean Jacques


    Over the past decade, the number of individuals taking calcium supplementation worldwide has been on the rise, especially with the emergence of new pharmaceutical companies specialized in the marketing of dietary supplements; with calcium supplementation being their main business axis. This is mostly because of the established role of calcium in the prevention and treatment of osteoporosis and, to a lesser extent, its role in the prevention of fractures. Recently, a rising body of evidence on the adverse effect of calcium supplementation on nonskeletal, especially cardiovascular, health has been a cause for concern. In fact, a significant number of studies have reported an association between calcium supplementation and adverse cardiovascular events, even though high dietary calcium intake was shown to have a protective effect. The mechanism by which calcium supplementation could cause a cardiovascular event was still unclear until a recent study published in the Journal of the American Heart Association. Combining this recent finding with available data associating calcium supplementation with cardiovascular mortality and all-cause mortality, we call on the need for an evidence-based approach to calcium supplementation, while stressing on the safety of dietary calcium intake over the former on cardiovascular health. ©2017 Wiley Periodicals, Inc.

  4. Calcium signals in olfactory neurons. (United States)

    Tareilus, E; Noé, J; Breer, H


    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.

  5. The increasing of enamel calcium level after casein phosphopeptideamorphous calcium phosphate covering


    Widyasri Prananingrum; Puguh Bayu Prabowo


    Background: Caries process is characterized by the presence of demineralization. Demineralization is caused by organic acids as a result of carbohydrate substrate fermentation. Remineralization is a natural repair process for non-cavitated lesions. Remineralization occurs if there are Ca2+ and PO43- ions in sufficient quantities. Casein-amorphous calcium phosphate phosphopeptide (CPP-ACP) is a paste material containing milk protein (casein), that actually contains minerals, such as calcium an...

  6. Modulation of intestinal absorption of calcium

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, P; Dupuis, Y [Ecole Pratique des Hautes Etudes, 75 - Paris (France); Paris-11 Univ., 92 - Chatenay-Malabry (France))


    Absorption of ingested calcium (2ml of a 10mM CaCl/sub 2/ solution + /sup 45/Ca) by the adult rat was shown to be facilitated by the simultaneous ingestion of an active carbohydrate, L-arabinose. As the carbohydrate concentration is increased from 10 to 200mM, the absorption of calcium is maximised at a level corresponding to about twice the control absorption level. A similar doubling of calcium absorption is obtained when a 100mM concentration of any one of a number of other carbohydrates is ingested simultaneously with a 10mM CaCl/sub 2/ solution. Conversely, the simultaneous ingestion of increasing doses (10 to 100mM) of phosphate (NaH/sub 2/PO/sub 4/) with a 10mM CaCl/sub 2/ solution results in decreased /sup 45/Ca absorption and retention by the adult rat. The maximum inhibition of calcium absorption by phosphate is independent of the concentration of the ingested calcium solution (from 5 to 50mM CaCl/sub 2/). The simultaneous ingestion of CaCl/sub 2/ (10mM) with lactose and sodium phosphate (50 and 10mM respectively) shows that the activation effect of lactose upon /sup 45/Ca absorption may be partly dissimulated by the presence of phosphate. These various observations indicate that, within a large concentration range (2 to 50mM CaCl/sub 2/) calcium absorption appears to be a precisely modulated diffusion process. Calcium absorption varies (between minimum and maximum levels) as a function of the state of saturation by the activators (carbohydrates) and inhibitors (phosphate) of the calcium transport system.

  7. Intracellular free calcium concentration and calcium transport in human erythrocytes of lead-exposed workers

    International Nuclear Information System (INIS)

    Quintanar-Escorza, M.A.; Gonzalez-Martinez, M.T.; Navarro, L.; Maldonado, M.; Arevalo, B.; Calderon-Salinas, J.V.


    Erythrocytes are the route of lead distribution to organs and tissues. The effect of lead on calcium homeostasis in human erythrocytes and other excitable cells is not known. In the present work we studied the effect of lead intoxication on the uptake and efflux (measured as (Ca 2+ -Mg 2+ )-ATPase activity) of calcium were studied in erythrocytes obtained from lead-exposed workers. Blood samples were taken from 15 workers exposed to lead (blood lead concentration 74.4 ± 21.9 μg/dl) and 15 non-exposed workers (9.9 ± 2 μg/dl). In erythrocytes of lead-exposed workers, the intracellular free calcium was 79 ± 13 nM, a significantly higher concentration (ANOVA, P 2+ -Mg 2+ )-ATPase activity. Lipid peroxidation was 1.7-fold higher in erythrocytes of lead-exposed workers as compared with control. The alteration on calcium equilibrium in erythrocytes is discussed in light of the toxicological effects in lead-exposed workers

  8. The calcium phosphate coating of soy lecithin nanoemulsion with performance in stability and as an oxygen carrier (United States)

    Han, Kyu B.

    This work studied the relationship between surfactant, oil, and water, by building ternary phase diagrams, the goal of which was to identify the oil-in-water phase composition. The resulting nano-sized emulsion was coated with dicalcium phosphate by utilizing the ionic affinity between calcium ions and the emulsion surface. Since the desired function of the particle is as an oxygen carrier, the particle stability, oxygen capacity, and oxygen release rate were investigated. The first step in the process was to construct ternary phase diagrams with 1,2-dioleoyl-sn-glycero-3-phosphate (DOPA) and soy derived lecithin. The results showed that the lecithin surfactant formed an oil-in-water phase region that was 36 times greater than that of DOPA. With the desired phase composition set, the lecithin emulsion was extruded, resulting in a well-dispersed nanosized particle. A pH titration study of the emulsion found an optimized calcium phosphate coating condition at pH 8.8, at which, the calcium ion had a greater affinity for the emulsion surface than phosphate. A Hill plot was used to show calcium cooperativeness on the emulsion surface which suggested one calcium ion binds to one lecithin molecule. The lecithin emulsion particles were then coated with calcium phosphate using a layering technique that allowed for careful control of the coating thickness. The overall particle hydrodynamic radius was consistent with the growth of the calcium phosphate coating, from 8 nm to 28 nm. This observation was further supported with cryo-TEM measurements. The stability of the coated emulsion was tested in conditions that simulate practical thermal, physical, and time-dependent conditions. Throughout the tests, the coated emulsion exhibited a constant mono-dispersed particle size, while the uncoated emulsion size fluctuated greatly and exhibited increased polydispersion. The fast mixing method with the stopped-flow apparatus was employed to test the product as an oxygen carrier, and it

  9. Solubility of calcium in CaO-CaCl2

    International Nuclear Information System (INIS)

    Perry, G.S.; Shaw, S.J.


    The Direct Oxide Reduction (DOR) process is well established as a process to produce plutonium metal from plutonium dioxide by reaction with calcium. Calcium chloride is added to dissolve the calcium oxide produced, allowing the metal to coalesce into a button. Since calcium metal melts at 840 0 C and DOR can take place successfully below this temperature, it is likely calcium dissolved in calcium chloride reacts with the plutonium dioxide. The solubility of calcium in calcium chloride is reasonably well established but the effect of the CaO formed during the DOR process on the solubility of calcium has not been previously determined. For this reason the solubility of calcium in CaCl 2 -CaO melts at 800 o C has been studied. The solubility decreases from 2.7 mol % in CaCl 2 to 0.4 mol % in 9 mol % CaO-CaCl 2 . (author)

  10. Hydrocarbon-soluble calcium hydride: a "worker-bee" in calcium chemistry. (United States)

    Spielmann, Jan; Harder, Sjoerd


    The reactivity of the hydrocarbon-soluble calcium hydride complex [{CaH(dipp-nacnac)(thf)}(2)] (1; dipp-nacnac=CH{(CMe)(2,6-iPr(2)C(6)H(3)N)}(2)) with a large variety of substrates has been investigated. Addition of 1 to C=O and C=N functionalities gave easy access to calcium alkoxide and amide complexes. Similarly, reduction of the C[triple chemical bond]N bond in a cyanide or an isocyanide resulted in the first calcium aldimide complexes [Ca{N=C(H)R}(dipp-nacnac)] and [Ca{C(H)=NR}(dipp-nacnac)], respectively. Complexation of 1 with borane or alane Lewis acids gave the borates and alanates as contact ion pairs. In reaction with epoxides, nucleophilic ring-opening is observed as the major reaction. The high reactivity of hydrocarbon-soluble 1 with most functional groups contrasts strongly with that of insoluble CaH(2), which is essentially inert and is used as a common drying agent. Crystal structures of the following products are presented: [{Ca{OC(H)Ph(2)}(dipp-nacnac)}(2)], [{Ca{N=C(H)Ph}(dipp-nacnac)}(2)], [{Ca{C(H)=NC(Me)(2)CH(2)C(Me)(3)}(dipp-nacnac)}(2)], [{Ca{C(H)=NCy}(dipp-nacnac)}(2)], [Ca(dipp-nacnac)(thf)](+)[H(2)BC(8)H(14)](-) and [{Ca(OCy)(dipp-nacnac)}(2)]. The generally smooth and clean conversions of 1 with a variety of substrates and the stability of most intermediates against ligand exchange make 1 a valuable key precursor in the syntheses of a wide variety of beta-diketiminate calcium complexes.

  11. The calcium and vitamin D controversy

    DEFF Research Database (Denmark)

    Abrahamsen, Bo


    Areas of the world where vitamin D levels are low for months of the year and intakes of calcium are high have a high prevalence of osteoporosis and cardiovascular disease. This suggests a public health message of avoiding calcium supplements and increasing vitamin D intake. No message could be more...... welcome as vitamin D can be given as a bolus while calcium must be taken daily and may be poorly tolerated. This approach is based on no evidence from intervention studies. Randomized controlled trials (RCTs) suggest that vitamin D given with calcium elicits a small reduction in fracture risk and deaths....... This has not been demonstrated for D given alone. The cardiovascular safety of calcium and vitamin D (CaD) supplements is difficult to ascertain due to weaknesses in RCT designs and adjudication that cannot be remedied by subanalysis. Moreover, no major new RCTs are in process to provide better evidence...

  12. Calcium as a cardiovascular toxin in CKD-MBD. (United States)

    Moe, Sharon M


    Disordered calcium balance and homeostasis are common in patients with chronic kidney disease. Such alterations are commonly associated with abnormal bone remodeling, directly and indirectly. Similarly, positive calcium balance may also be a factor in the pathogenesis of extra skeletal soft tissue and arterial calcification. Calcium may directly affect cardiac structure and function through direct effects to alter cell signaling due to abnormal intracellular calcium homeostasis 2) extra-skeletal deposition of calcium and phosphate in the myocardium and small cardiac arterioles, 3) inducing cardiomyocyte hypertrophy through calcium and hormone activation of NFAT signaling mechanisms, and 4) increased aorta calcification resulting in chronic increased afterload leading to hypertrophy. Similarly, calcium may alter vascular smooth muscle cell function and affect cell signaling which may predispose to a proliferative phenotype important in arteriosclerosis and arterial calcification. Thus, disorders of calcium balance and homeostasis due to CKD-MBD may play a role in the high cardiovascular burden observed in patients with CKD. Published by Elsevier Inc.

  13. Lactulose stimulates calcium absorption in postmenopausal women

    NARCIS (Netherlands)

    Heuvel, E.G.H.M. van den; Muijs, T.; Dokkum, W. van; Schaafsma, G.


    Animal studies have indicated that calcium absorption is increased by lactulose, a synthetic disaccharide. Therefore, the influence of lactulose on calcium absorption was measured in postmenopausal women who may benefit from the possible enhancing effect of lactulose on calcium absorption. Twelve

  14. Effects of Oxcarbazepine and Levetiracetam on Calcium, Ionized Calcium, and 25-OH Vitamin-D3 Levels in Patients with Epilepsy. (United States)

    Aksoy, Duygu; Güveli, Betül Tekin; Ak, Pelin Doğan; Sarı, Hüseyin; Ataklı, Dilek; Arpacı, Baki


    The primary objective of the present study was to further elucidate the effects of oxcarbazepine (OXC) and levetiracetam (LEV) monotherapies on the bone health status of patients with epilepsy. This study included 48 patients who attended our epilepsy outpatient clinic, had a diagnosis of epilepsy, and were undergoing either OXC or LEV monotherapy and 42 healthy control subjects. The demographic and clinical features of the patients, including gender, age, onset of disease, daily drug dosage, and duration of disease, were noted. Additionally, the calcium, ionized calcium, and 25-OH vitamin-D3 levels of the participants were prospectively evaluated. The 25-OH vitamin-D3, calcium, and ionized calcium levels of the patients taking OXC were significantly lower than those of the control group. These levels did not significantly differ between the patients taking LEV and the control group, but there was a significant negative relationship between daily drug dose and ionized calcium levels in the LEV patients. In the present study, anti-epileptic drugs altered the calcium, ionized calcium, and 25-OH vitamin-D3 levels of epilepsy patients and resulted in bone loss, abnormal mineralization, and fractures. These findings suggest that the calcium, ionized calcium, and 25-OH vitamin-D3 levels of patients with epilepsy should be regularly assessed.

  15. Visualisation of an nsPEF induced calcium wave using the genetically encoded calcium indicator GCaMP in U87 human glioblastoma cells. (United States)

    Carr, Lynn; Bardet, Sylvia M; Arnaud-Cormos, Delia; Leveque, Philippe; O'Connor, Rodney P


    Cytosolic, synthetic chemical calcium indicators are typically used to visualise the rapid increase in intracellular calcium ion concentration that follows nanosecond pulsed electric field (nsPEF) application. This study looks at the application of genetically encoded calcium indicators (GECIs) to investigate the spatiotemporal nature of nsPEF-induced calcium signals using fluorescent live cell imaging. Calcium responses to 44kV/cm, 10ns pulses were observed in U87-MG cells expressing either a plasma membrane targeted GECI (GCaMP5-G), or one cytosolically expressed (GCaMP6-S), and compared to the response of cells loaded with cytosolic or plasma membrane targeted chemical calcium indicators. Application of 100 pulses, to cells containing plasma membrane targeted indicators, revealed a wave of calcium across the cell initiating at the cathode side. A similar spatial wave was not observed with cytosolic indicators with mobile calcium buffering properties. The speed of the wave was related to pulse application frequency and it was not propagated by calcium induced calcium release. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Monitoring the progression of calcium and protein solubilisation as affected by calcium chelators during small-scale manufacture of casein-based food matrices. (United States)

    McIntyre, Irene; O'Sullivan, Michael; O'Riordan, Dolores


    Calcium and protein solubilisation during small-scale manufacture of semi-solid casein-based food matrices was investigated and found to be very different in the presence or absence of calcium chelating salts. Calcium concentrations in the dispersed phase increased and calcium-ion activity (A Ca ++ ) decreased during manufacture of the matrices containing calcium chelating salts; with ∼23% of total calcium solubilised by the end of manufacture. In the absence of calcium chelating salts, these concentrations were significantly lower at equivalent processing times and remained unchanged as did A Ca ++ , throughout manufacture. The protein content of the dispersed phase was low (≤3% of total protein), but was significantly higher for matrices containing calcium chelating salts. This study elucidates the critical role of calcium chelating salts in modulating casein hydration and dispersion and gives an indication of the levels of soluble calcium and protein required to allow matrix formation during manufacture of casein-based food structures e.g. processed and analogue cheese. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Effects of nano calcium carbonate and nano calcium citrate on toxicity in ICR mice and on bone mineral density in an ovariectomized mice model

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Sherry; Chen, Jin Ching; Hsu, Chin Wei; Chang, Walter H, E-mail: [Center for Nano Bioengineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Department of Biomedical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China)


    Taking calcium supplements can reduce the risk of developing osteoporosis, but they are not readily absorbed in the gastrointestinal tract. Nanotechnology is expected to resolve this problem. In the present study, we examined whether the bioavailability of calcium carbonate and calcium citrate can be improved by reducing the particle size. The morphology of nano calcium carbonate and nano calcium citrate was characterized by dynamic laser-light scattering (DLS), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The measurements obtained from DLS, FE-SEM and TEM were comparable. Acute and sub-chronic toxicity tests were performed to establish the safety of these products after oral administration. The no-observed-adverse-effect levels of nano calcium carbonate and nano calcium citrate were 1.3 and 2.3 g kg{sup -1} body weight, respectively. The results of our in vivo studies indicate that administering nano calcium carbonate and nano calcium citrate can enhance the serum calcium concentration and maintain the whole-body bone mineral density in ovariectomized mice. These data suggest that nano calcium carbonate and nano calcium citrate are more bioavailable than micro calcium carbonate and micro calcium citrate, respectively.

  18. Calcium and Calcium Supplements: Achieving the Right Balance (United States)

    ... may have on heart attack risk. A similar controversy surrounds calcium and prostate cancer. Some studies have ... your agreement to the Terms and Conditions and Privacy Policy linked below. Terms and Conditions Privacy Policy ...

  19. Optimal Dose of Calcium for Treatment of Nutritional Rickets: A Randomized Controlled Trial. (United States)

    Thacher, Tom D; Smith, Lauren; Fischer, Philip R; Isichei, Christian O; Cha, Stephen S; Pettifor, John M


    Calcium supplementation is indicated for the treatment of nutritional rickets. Our aim was to determine the optimal dose of calcium for treatment of children with rickets. Sixty-five Nigerian children with radiographically confirmed rickets were randomized to daily supplemental calcium intake of 500 mg (n = 21), 1000 mg (n = 23), or 2000 mg (n = 21). Venous blood, radiographs, and forearm areal bone density (aBMD) were obtained at baseline and at 8, 16, and 24 weeks after enrollment. The primary outcome was radiographic healing, using a 10-point radiographic severity score. The radiographic severity scores improved in all three groups, but the rate of radiographic healing (points per month) was significantly more rapid in the 1000-mg (-0.29; 95% confidence interval [CI] -0.13 to -0.45) and 2000-mg (-0.36; 95% CI -0.19 to -0.53) supplementation groups relative to the 500-mg group. The 2000-mg group did not heal more rapidly than the 1000-mg group. Of those who completed treatment for 24 weeks, 12 (67%), 20 (87%), and 14 (67%) in the 2000-mg, 1000-mg, and 500-mg groups, respectively, had achieved a radiographic score of 1.5 or less (p = 0.21). Serum alkaline phosphatase decreased and calcium increased similarly in all groups. Forearm diaphyseal aBMD improved significantly more rapidly in the 2000-mg group than in the 500-mg and 1000-mg groups (p rickets than 500 mg, but 2000 mg did not have greater benefit than 1000 mg. Some children require longer than 24 weeks for complete healing of nutritional rickets. © 2016 American Society for Bone and Mineral Research. © 2016 American Society for Bone and Mineral Research.

  20. Calcium and Bone Metabolism Indices. (United States)

    Song, Lu


    Calcium and inorganic phosphate are of critical importance for many body functions, thus the regulations of their plasma concentrations are tightly controlled by the concerted actions of reabsorption/excretion in the kidney, absorption in the intestines, and exchange from bone, the major reservoir for calcium and phosphate in the body. Parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D (1,25(OH) 2 D) control calcium homeostasis, whereas PTH, 1,25(OH) 2 D, and bone-derived fibroblast growth factor 23 (FGF 23) control phosphate homeostasis. Hypoparathyroidism can cause hypocalcemia and hyperphosphatemia, whereas deficient vitamin D actions can cause osteomalacia in adults and rickets in children. Hyperparathyroidism, alternatively, can cause hypercalcemia and hypophosphatemia. Laboratory tests of calcium, phosphate, PTH, and 25-hydroxyvitamin D are very useful in the diagnosis of abnormalities associated with calcium and/or phosphate metabolisms. Bone is constantly remodeled throughout life in response to mechanical stress and a need for calcium in extracellular fluids. Metabolic bone diseases such as osteoporosis, osteomalacia in adults or rickets in children, and renal osteodystrophy develop when bone resorption exceeds bone formation. Bone turnover markers (BTM) such as serum N-terminal propeptide of type I procollagen (P1NP) and C-terminal collagen cross-link (CTX) may be useful in predicting future fracture risk or monitoring the response to anti-resorptive therapy. There is a need to standardize sample collection protocols because certain BTMs exhibit large circadian variations and tend to be influenced by food intakes. In the United States, a project to standardize BTM sample collection protocols and to establish the reference intervals for serum P1NP and serum CTX is ongoing. We anticipate the outcome of this project to shine lights on the standardization of BTM assays, sample collection protocols, reference intervals in relation to age, sex, and ethnic

  1. Does calcium constrain reproductive activity in insectivorous bats ...

    African Journals Online (AJOL)

    Insects are a poor source of dietary calcium and since they are seasonally abundant, it has been suggested that calcium availability may play a significant role in controlling the timing of reproduction in insectivorous bats. To assess the possible role of dietary calcium, we have measured bone calcium concentrations in ...

  2. Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture* (United States)

    Mauceri, Daniela; Hagenston, Anna M.; Schramm, Kathrin; Weiss, Ursula; Bading, Hilmar


    Calcium-binding proteins (CaBPs) such as parvalbumin are part of the cellular calcium buffering system that determines intracellular calcium diffusion and influences the spatiotemporal dynamics of calcium signals. In neurons, CaBPs are primarily localized to the cytosol and function, for example, in nerve terminals in short-term synaptic plasticity. However, CaBPs are also expressed in the cell nucleus, suggesting that they modulate nuclear calcium signals, which are key regulators of neuronal gene expression. Here we show that the calcium buffering capacity of the cell nucleus in mouse hippocampal neurons regulates neuronal architecture by modulating the expression levels of VEGFD and the complement factor C1q-c, two nuclear calcium-regulated genes that control dendrite geometry and spine density, respectively. Increasing the levels of nuclear calcium buffers by means of expression of a nuclearly targeted form of parvalbumin fused to mCherry (PV.NLS-mC) led to a reduction in VEGFD expression and, as a result, to a decrease in total dendritic length and complexity. In contrast, mRNA levels of the synapse pruning factor C1q-c were increased in neurons expressing PV.NLS-mC, causing a reduction in the density and size of dendritic spines. Our results establish a close link between nuclear calcium buffering capacity and the transcription of genes that determine neuronal structure. They suggest that the development of cognitive deficits observed in neurological conditions associated with CaBP deregulation may reflect the loss of necessary structural features of dendrites and spines. PMID:26231212

  3. Calcium phosphates for biomedical applications

    Directory of Open Access Journals (Sweden)

    Maria Canillas


    Full Text Available The history of calcium phosphates in the medicine field starts in 1769 when the first evidence of its existence in the bone tissue is discovered. Since then, the interest for calcium phosphates has increased among the scientific community. Their study has been developed in parallel with new advances in materials sciences, medicine or tissue engineering areas. Bone tissue engineering is the field where calcium phosphates have had a great importance. While the first bioceramics are selected according to bioinert, biocompatibility and mechanical properties with the aim to replace bone tissue damaged, calcium phosphates open the way to the bone tissue regeneration challenge. Nowadays, they are present in the majority of commercial products directed to repair or regenerate damaged bone tissue. Finally, in the last few decades, they have been suggested and studied as drug delivering devices and as vehicles of DNA and RNA for the future generation therapies.

  4. Calcium phosphates for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Canillas, M.; Pena, P.; Aza, A.H. de; Rodriguez, M.A.


    The history of calcium phosphates in the medicine field starts in 1769 when the first evidence of its existence in the bone tissue is discovered. Since then, the interest for calcium phosphates has increased among the scientific community. Their study has been developed in parallel with new advances in materials sciences, medicine or tissue engineering areas. Bone tissue engineering is the field where calcium phosphates have had a great importance. While the first bioceramics are selected according to bioinert, biocompatibility and mechanical properties with the aim to replace bone tissue damaged, calcium phosphates open the way to the bone tissue regeneration challenge. Nowadays, they are present in the majority of commercial products directed to repair or regenerate damaged bone tissue. Finally, in the last few decades, they have been suggested and studied as drug delivering devices and as vehicles of DNA and RNA for the future generation therapies. (Author)

  5. Application of Calcium Phosphate Materials in Dentistry

    Directory of Open Access Journals (Sweden)

    Jabr S. Al-Sanabani


    Full Text Available Calcium phosphate materials are similar to bone in composition and in having bioactive and osteoconductive properties. Calcium phosphate materials in different forms, as cements, composites, and coatings, are used in many medical and dental applications. This paper reviews the applications of these materials in dentistry. It presents a brief history, dental applications, and methods for improving their mechanical properties. Notable research is highlighted regarding (1 application of calcium phosphate into various fields in dentistry; (2 improving mechanical properties of calcium phosphate; (3 biomimetic process and functionally graded materials. This paper deals with most common types of the calcium phosphate materials such as hydroxyapatite and tricalcium phosphate which are currently used in dental and medical fields.

  6. Fast kinetics of calcium dissociation from calsequestrin

    Directory of Open Access Journals (Sweden)



    Full Text Available We measured the kinetics of calcium dissociation from calsequestrin in solution or forming part of isolated junctional sarcoplasmic reticulum membranes by mixing calsequestrin equilibrated with calcium with calcium-free solutions in a stopped-flow system. In parallel, we measured the kinetics of the intrinsic fluorescence changes that take place following calcium dissociation from calsequestrin. We found that at 25ºC calcium dissociation was 10-fold faster for calsequestrin attached to junctional membranes (k = 109 s-1 than in solution. These results imply that calcium dissociation from calsequestrin in vivo is not rate limiting during excitation-contraction coupling. In addition, we found that the intrinsic fluorescence decrease for calsequestrin in solution or forming part of junctional membranes was significantly slower than the rates of calcium dissociation. The kinetics of intrinsic fluorescence changes had two components for calsequestrin associated to junctional membranes and only one for calsequestrin in solution; the faster component was 8-fold faster (k = 54.1 s-1 than the slower component (k = 6.9 s-1, which had the same k value as for calsequestrin in solution. These combined results suggest that the presence of calsequestrin at high concentrations in a restricted space, such as when bound to the junctional membrane, accelerates calcium dissociation and the resulting structural changes, presumably as a result of cooperative molecular interactions.

  7. Brain calcium - Role in temperature regulation. (United States)

    Hanegan, J. L.; Williams, B. A.


    Perfusion of the preoptic-anterior hypothalamus with excess calcium ion in ground squirrels produces a drop in core temperature. The magnitude of the drop is directly dependent on ambient temperature. Respiration, heart rate, and oxygen consumption are also reduced during perfusion of calcium ion. It is concluded that the depression of body temperature during calcium ion perfusion is due to generalized depression of the neurons of the preoptic-anterior hypothalamus.

  8. Solubility and bioavailability of stabilized amorphous calcium carbonate. (United States)

    Meiron, Oren E; Bar-David, Elad; Aflalo, Eliahu D; Shechter, Assaf; Stepensky, David; Berman, Amir; Sagi, Amir


    Since its role in the prevention of osteoporosis in humans was proven some 30 years ago, calcium bioavailability has been the subject of numerous scientific studies. Recent technology allowing the production of a stable amorphous calcium carbonate (ACC) now enables a bioavailability analysis of this unique form of calcium. This study thus compares the solubility and fractional absorption of ACC, ACC with chitosan (ACC-C), and crystalline calcium carbonate (CCC). Solubility was evaluated by dissolving these preparations in dilute phosphoric acid. The results demonstrated that both ACC and ACC-C are more soluble than CCC. Fractional absorption was evaluated by intrinsically labeling calcium carbonate preparations with (45)Ca, orally administrated to rats using gelatin capsules. Fractional absorption was determined by evaluating the percentage of the administrated radioactive dose per milliliter that was measured in the serum, calcium absorption in the femur, and whole-body retention over a 34-hour period. Calcium serum analysis revealed that calcium absorption from ACC and ACC-C preparations was up to 40% higher than from CCC, whereas retention of ACC and ACC-C was up to 26.5% higher than CCC. Absorbed calcium in the femurs of ACC-administrated rats was 30% higher than in CCC-treated animals, whereas 15% more calcium was absorbed following ACC-C treatment than following CCC treatment. This study demonstrates the enhanced solubility and bioavailability of ACC over CCC. The use of stable ACC as a highly bioavailable dietary source for calcium is proposed based on the findings of this study. Copyright © 2011 American Society for Bone and Mineral Research.

  9. Calcium and Nuclear Signaling in Prostate Cancer


    Ivan V. Maly; Wilma A. Hofmann


    Recently, there have been a number of developments in the fields of calcium and nuclear signaling that point to new avenues for a more effective diagnosis and treatment of prostate cancer. An example is the discovery of new classes of molecules involved in calcium-regulated nuclear import and nuclear calcium signaling, from the G protein-coupled receptor (GPCR) and myosin families. This review surveys the new state of the calcium and nuclear signaling fields with the aim of identifying the un...

  10. The effect of glucose stimulation on 45calcium uptake of rat pancreatic islets and their total calcium content as measured by a fluorometric micro-method

    International Nuclear Information System (INIS)

    Wolters, G.H.J.; Wiegman, J.B.; Konijnendijk, W.


    Glucose-stimulated 45 calcium uptake and total calcium content of rat pancreatic islets has been studied, using a new fluorometric micro-method to estimate total calcium. Extracellular calcium was separated from incubated tissue by a rapid micro-filtration procedure. Islets incubated up to 60 min with calcium chloride 2.5 mmol/l and glucose 2.5 mmol/l maintained the same calcium content (670 +- 7.5 pmol/μg DNA). When the glucose concentration was raised to 15 mmol/l no change in the total calcium content could be detected. On incubation with glucose 2.5 mmol/l in the absence of calcium, the calcium content decreased to 488 +- 27 pmol/μg DNA. On incubation with 45 calcium chloride 2.5 mmol/l for 5 or 30 min at 2.5 mmol/l glucose, islets exchanged 21 +- 2 and 28 +- 1% of their total calcium content and, at 15 mmol/l glucose, 30 +- 3 and 45 +- 2%, respectively. Thus, islet calcium has a high turn-over rate. Glucose stimulation results in an increase of the calcium uptake without enhancing the total calcium content and hence must increase the calcium-exchangeable pool. (orig.)

  11. Effects of calcium hydroxide addition on the physical and chemical properties of a calcium silicate-based sealer. (United States)

    Kuga, Milton Carlos; Duarte, Marco Antonio Hungaro; Sant'anna-Júnior, Arnaldo; Keine, Kátia Cristina; Faria, Gisele; Dantas, Andrea Abi Rached; Guiotti, Flávia Angélica


    Recently, various calcium silicate-based sealers have been introduced for use in root canal filling. The MTA Fillapex is one of these sealers, but some of its physicochemical properties are not in accordance with the ISO requirements. The aim of this study was to evaluate the flowability, pH level and calcium release of pure MTA Fillapex (MTAF) or containing 5% (MTAF5) or 10% (MTAF10) calcium hydroxide (CH), in weight, in comparison with AH Plus sealer. The flowability test was performed according to the ISO 6876:2001 requirements. For the pH level and calcium ion release analyses, the sealers were placed individually (n=10) in plastic tubes and immersed in deionized water. After 24 hours, 7 and 14 days, the water in which each specimen had been immersed was evaluated to determine the pH level changes and calcium released. Flowability, pH level and calcium release data were analyzed statistically by the ANOVA test (α=5%). In relation to flowability: MTAF>AH Plus>MTAF5>MTAF10. In relation to the pH level, for 24 h: MTAF5=MTAF10=MTAF>AH Plus; for 7 and 14 days: MTAF5=MTAF10>MTAF>AH Plus. For the calcium release, for all periods: MTAF>MTAF5=MTAF10>AH Plus. The addition of 5% CH to the MTA Fillapex (in weight) is an alternative to reduce the high flowability presented by the sealer, without interfering in its alkalization potential.

  12. First quantification of calcium intake from calcium-dense dairy products in Dutch fracture patients (the Delft cohort study). (United States)

    van den Berg, Peter; van Haard, Paul M M; van den Bergh, Joop P W; Niesten, Dieu Donné; van der Elst, Maarten; Schweitzer, Dave H


    Recommendations for daily calcium intake from dairy products are variable and based on local consensus. To investigate whether patients with a recent fracture complied with these recommendations, we quantified the daily dairy calcium intake including milk, milk drinks, pudding, yoghurt, and cheese in a Dutch cohort of fracture patients and compared outcomes with recent data of a healthy U.S. cohort (80% Caucasians). An observational study analyzed dairy calcium intakes of 1526 female and 372 male Dutch fracture patients older than 50. On average, participants reported three dairy servings per day, independently of age, gender or population density. Median calcium intake from dairy was 790 mg/day in females and males. Based on dairy products alone, 11.3% of women and 14.2% of men complied with Dutch recommendations for calcium intake (adults ≤ 70 years: 1100 mg/day and >70 years: 1200 mg/day). After including 450 mg calcium from basic nutrition, compliance raised to 60.5% and 59.1%, respectively, compared to 53.2% in the U.S. cohort. Daily dairy calcium intake is not associated with femoral neck bone mineral density (BMD) T-scores or WHO Fracture Assessment Tool (FRAX) risk scores for major fracture or hip fracture. However, when sub analyzing the male cohort, these associations were weakly negative. The prevalence of maternal hip fracture was a factor for current fracture risks, both in women and men. While daily dairy calcium intake of Dutch fracture patients was well below the recommended dietary intake, it was comparable to intakes in a healthy U.S. cohort. This questions recommendations for adding more additional dairy products to preserve adult skeletal health, particularly when sufficient additional calcium is derived from adequate non-dairy nutrition.

  13. First Quantification of Calcium Intake from Calcium-Dense Dairy Products in Dutch Fracture Patients (The Delft Cohort Study

    Directory of Open Access Journals (Sweden)

    Peter van den Berg


    Full Text Available Recommendations for daily calcium intake from dairy products are variable and based on local consensus. To investigate whether patients with a recent fracture complied with these recommendations, we quantified the daily dairy calcium intake including milk, milk drinks, pudding, yoghurt, and cheese in a Dutch cohort of fracture patients and compared outcomes with recent data of a healthy U.S. cohort (80% Caucasians. An observational study analyzed dairy calcium intakes of 1526 female and 372 male Dutch fracture patients older than 50. On average, participants reported three dairy servings per day, independently of age, gender or population density. Median calcium intake from dairy was 790 mg/day in females and males. Based on dairy products alone, 11.3% of women and 14.2% of men complied with Dutch recommendations for calcium intake (adults ≤ 70 years: 1100 mg/day and >70 years: 1200 mg/day. After including 450 mg calcium from basic nutrition, compliance raised to 60.5% and 59.1%, respectively, compared to 53.2% in the U.S. cohort. Daily dairy calcium intake is not associated with femoral neck bone mineral density (BMD T-scores or WHO Fracture Assessment Tool (FRAX risk scores for major fracture or hip fracture. However, when sub analyzing the male cohort, these associations were weakly negative. The prevalence of maternal hip fracture was a factor for current fracture risks, both in women and men. While daily dairy calcium intake of Dutch fracture patients was well below the recommended dietary intake, it was comparable to intakes in a healthy U.S. cohort. This questions recommendations for adding more additional dairy products to preserve adult skeletal health, particularly when sufficient additional calcium is derived from adequate non-dairy nutrition.

  14. Can atorvastatin calcium cause asymptomatic hypercalcemia? (United States)

    Ipekçi, Süleyman Hilmi; Baldane, Süleyman; Sözen, Mehmet; Kebapçılar, Levent


    The use of statins may have unnatural effects. A 54-year-old woman was admitted to the hospital with an incidental finding of hypercalcemia (10.8 mg/dL). There was no disease other than hyperlipidemia, and the patient had been on a course of atorvastatin calcium 10 mg for 1.5 years. A workup investigation to diagnose the cause of hypercalcemia was completed. The investigation did not reveal any pathological diseases that may have caused the hypercalcemia. The hypercalcemia resolved after atorvastatin-calcium was stopped, and the patient developed hypercalcemia shortly after the initiation of the atorvastatin calcium. Here, we report a clinical case of recurrent hypercalcemia possibly induced by atorvastatin calcium administration.

  15. Pilot-scale demonstration of the OSCAR process for high-temperature multipollutant control of coal combustion flue gas, using carbonated fly ash and mesoporous calcium carbonate

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, H.; Thomas, T.J.; Park, A.H.A.; Iyer, M.V.; Gupta, P.; Agnihotri, R.; Jadhav, R.A.; Walker, H.W.; Weavers, L.K.; Butalia, T.; Fan, L.S. [Ohio State University, Columbus, OH (United States)


    A pilot-scale study of the Ohio State Carbonation Ash Reactivation (OSCAR) process was performed to demonstrate the reactivity of two novel calcium-based sorbents toward sulfur and trace heavy metal (arsenic, selenium, and mercury) capture in the furnace sorbent injection (FSI) mode on a 0.365 m{sup 3}/s slipstream of a bituminous coal-fired stoker boiler. The sorbents were synthesized by bubbling CO{sub 2} to precipitate calcium carbonate (a) from the unreacted calcium present in the lime spray dryer ash and (b) from calcium hydroxide slurry that contained a negatively charged dispersant. The heterogeneous reaction between these sorbents and SO{sub 2} gas occurred under entrained flow conditions by injecting fine sorbent powders into the flue gas slipstream. The reacted sorbents were captured either in a hot cyclone (about 650{sup o}C) or in the relatively cooler downstream baghouse (about 230{sup o}C). The baghouse samples indicated about 90% toward sulfation and captured arsenic, selenium and mercury to 800 ppmw, 175 ppmw and 3.6 ppmw, respectively.

  16. Calcium-sensing receptor gene polymorphism (rs7652589) is associated with calcium nephrolithiasis in the population of Yi nationality in Southwestern China. (United States)

    Li, Hao; Zhang, Jianhua; Long, Jiang; Shi, Jiarun; Luo, Yuhui


    The calcium-sensing receptor (CaSR) gene plays an important role in regulating the Ca 2+ balance and reducing the risk for calcium stones. In this study, we evaluated the association of CaSR polymorphisms with calcium nephrolithiasis in the population of Yi nationality in Southwestern China. Biochemical variables were evaluated in 624 calcium nephrolithiasis patients and 470 age-matched healthy controls without a history of nephrolithiasis. CaSR polymorphisms rs7652589, rs1501899, rs1801725 (Ala986Ser), rs1042636 (Arg990Gly) and rs1801726 (Gln1011Glu) were investigated between the calcium nephrolithiasis patients and healthy controls, using direct sequencing. Compared with the healthy controls, serum creatinine and 24-hour urine calcium levels were significantly higher in calcium nephrolithiasis patients. Among these five polymorphisms, the genotypic and allelic frequency distributions of rs7652589 SNP was significantly associated with the risk of calcium nephrolithiasis. However, there were no genotypic or allelic distribution differences for rs1501899, rs1801725, rs1042636, and rs1801726 polymorphisms between calcium nephrolithiasis patients and healthy controls. Moreover, the association between rs7652589 SNP genotypes and the biochemical variables was not found. Our study showed that CaSR rs7652589 polymorphism had a significant effect on the risk of developing calcium nephrolithiasis in the population of Yi nationality in Southwestern China. © 2018 John Wiley & Sons Ltd/University College London.

  17. Lead in calcium supplements (abstract)

    International Nuclear Information System (INIS)

    Rehman, S.; Khalid, N.


    Lead present in calcium supplements is of grave concern as some lead levels have been measured up to the extent of regulatory limit set by the United States. Calcium supplements inevitably get contaminated with lead as both are naturally occurring elements. Therefore, it is imperative to indicate its level in these supplements in order to create awareness among consumers. In this study, a sophisticated analytical technique, atomic absorption spectrometry was used to analyze Pb contents in 27 commonly consumed Ca supplements manufactured by different national and multinational companies. The daily intake of lead through these supplements was calculated. Only 10% of the calcium supplements analyzed met the criteria of acceptable Pb levels (1.5 mu g/daily dose) in supplements/consumer products set by the United States. It was also found that Pb intake was highest in chelated calcium supplements 28.5 mu g/daily dose, whereas lowest 0.47 mu g/daily dose through calcium supplements with vitamin D formulation. In order to validate our results from the study conducted, IAEA-certified reference material (animal bone, H-5) was analyzed for its Pb levels. The levels of Pb determined were quite in good agreement with the certified values. (author)

  18. Effect of calcium supplements on osteoporosis by using nuclear analytical techniques

    International Nuclear Information System (INIS)

    Sumin Hu; Xueying Mao; Hong Ouyang


    Neutron activation analysis (NAA) and dual energy X-ray absorptiometry (DEXA) have been used to study the effects of different calcium supplements on osteoporosis, including calcium carbonate, calcium threonate, calcium gluconate, calcium lactate, calcium acetate and a traditional Chinese medicine. Animal test results showed that calcium carbonate, calcium gluconate, calcium acetate and the Chinese medicine notably increased osteoporotic rat's femoral bone mineral density (BMD). Also, calcium carbonate, calcium acetate and the Chinese medicine significantly increased osteoporotic rat's vertebral BMD. But calcium L-threonate and calcium lactate had no such effects. Calcium gluconate, calcium acetate and the Chinese medicine improved the bone mechanical intensity of osteoporotic rats. The results of NAA showed that the loss of elements in spongy bones was more seriously than that in compact bone and was difficult to be improved. (author)

  19. Calcium and Egg Activation in Drosophila (United States)

    Sartain, Caroline V.; Wolfner, Mariana F.


    Summary In many animals, a rise in intracellular calcium levels is the trigger for egg activation, the process by which an arrested mature oocyte transitions to prepare for embryogenesis. In nearly all animals studied to date, this calcium rise, and thus egg activation, is triggered by the fertilizing sperm. However in the insects that have been examined, fertilization is not necessary to activate their oocytes. Rather, these insects’ eggs activate as they transit through the female’s reproductive tract, regardless of male contribution. Recent studies in Drosophila have shown that egg activation nevertheless requires calcium and that the downstream events and molecules of egg activation are also conserved, despite the difference in initial trigger. Genetic studies have uncovered essential roles for the calcium-dependent enzyme calcineurin and its regulator calcipressin, and have hinted at roles for calmodulin, in Drosophila egg activation. Physiological and in vitro studies have led to a model in which mechanical forces that impact the Drosophila oocyte as it moves through the reproductive tract triggers the influx of calcium from the external environment, thereby initiating egg activation. Future research will aim to test this model, as well as to determine the spatiotemporal dynamics of cytoplasmic calcium flux and mode of signal propagation in this unique system. PMID:23218670

  20. Genetic polymorphisms in calcitonin receptor gene and risk for recurrent kidney calcium stone disease. (United States)

    Shakhssalim, Nasser; Basiri, Abbas; Houshmand, Massoud; Pakmanesh, Hamid; Golestan, Banafsheh; Azadvari, Mohaddeseh; Aryan, Hajar; Kashi, Amir H


    In this study the full sequence of the calcitonin receptor gene (CALCR) in a group of Iranian males suffering from recurrent calcium urinary stones was compared with that of a control group. Serum and urinary biochemistry related to urolithiasis were evaluated in 105 males diagnosed with recurrent kidney calcium stones and 101 age-matched healthy control males. The polymerase chain reaction single-strand conformation polymorphism method was used to detect new polymorphisms in the CALCR. Nine polymorphisms were detected; seven were in the non-coding and two in the coding region. The T allele associated with the 3'UTR+18C>T polymorphism was observed exclusively in the stone formers. The exact odds ratio for the T allele in this locus for those at risk of stone formation was 36.72 (95% CI 4.95-272.0) (p C and IVS1insA polymorphisms in intron 1 were associated with kidney stone disease (p T and intron 1 polymorphisms in the CALCR and the risk of kidney stone disease. 2013 S. Karger AG, Basel.

  1. A study of calcium intake and sources of calcium in adolescent boys and girls from two socioeconomic strata, in Pune, India. (United States)

    Sanwalka, Neha J; Khadilkar, Anuradha V; Mughal, M Zulf; Sayyad, Mehmood G; Khadilkar, Vaman V; Shirole, Shilpa C; Divate, Uma P; Bhandari, Dhanshari R


    Adequate intake of calcium is important for skeletal growth. Low calcium intake during childhood and adolescence may lead to decreased bone mass accrual thereby increasing the risk of osteoporotic fractures. Our aim was to study dietary calcium intake and sources of calcium in adolescents from lower and upper economic strata in Pune, India. We hypothesized that children from lower economic strata would have lower intakes of calcium, which would predominantly be derived from non-dairy sources. Two hundred male and female adolescents, from lower and upper economic stratum were studied. Semiquantitative food frequency questionnaire was used to evaluate intakes of calcium, phosphorus, oxalic acid, phytin, energy and protein. The median calcium intake was significantly different in all four groups, with maximum intake in the upper economic strata boys (893 mg, 689-1295) and lowest intake in lower economic strata girls (506 mg, 380-674). The median calcium intake in lower economic strata boys was 767 mg (585-1043) and that in upper economic strata girls was 764 mg (541-959). The main source of calcium was dairy products in upper economic strata adolescents while it was dark green leafy vegetables in lower economic strata adolescents. The median calcium intake was much lower in lower economic strata than in the upper economic strata both in boys and girls. Girls from both groups had less access to dairy products as compared to boys. Measures need to be taken to rectify low calcium intake in lower economic strata adolescents and to address gender inequality in distribution of dairy products in India.

  2. Calcium content of different compositions of gallstones and pathogenesis of calcium carbonate gallstones

    Directory of Open Access Journals (Sweden)

    Ji-Kuen Yu


    Conclusion: From our study, we found chronic and/or intermittent cystic duct obstructions and low-grade GB wall inflammation lead to GB epithelium hydrogen secretion dysfunction. Increased calcium ion efflux into the GB lumen combined with increased carbonate anion presence increases SI_CaCO3 from 1 to 22.4. Thus, in an alkaline milieu with pH 7.8, calcium carbonate begins to aggregate and precipitate.

  3. 21 CFR 582.2122 - Aluminum calcium silicate. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum calcium silicate. 582.2122 Section 582.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent. (c...

  4. 21 CFR 182.2122 - Aluminum calcium silicate. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum calcium silicate. 182.2122 Section 182.2122 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....2122 Aluminum calcium silicate. (a) Product. Aluminum calcium silicate. (b) Tolerance. 2 percent. (c...

  5. Synthesis and characterization of the aluminium phosphates modified with ammonium, calcium and molybdenum by hydrothermal method

    Directory of Open Access Journals (Sweden)

    Łuczka Kinga


    Full Text Available Synthesis and characterization of the aluminum phosphates modified with ammonium, calcium and molybdenum were conducted. The influence of process parameters (reactive pressure and molar ratios in the reaction mixture were studied. The contents of the individual components in the products were in the range of: 10.97–17.31 wt% Al, 2.65–13.32 wt% Ca, 0.70–3.11 wt% Mo, 4.36–8.38 wt% NH3, and 35.12–50.54 wt% P2O5. The materials obtained in the experiments were characterized by various physicochemical parameters. The absorption oil number was in the range from 67 to 89 of oil/100 g of product, the surface area was within the range of 4–76 m2/g, whereas the average particle size of products reached 282–370 nm. The Tafel tests revealed comparable anticorrosive properties of aluminum phosphates modified with ammonium, calcium, molybdenum in comparison with commercial phosphate.

  6. Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture. (United States)

    Mauceri, Daniela; Hagenston, Anna M; Schramm, Kathrin; Weiss, Ursula; Bading, Hilmar


    Calcium-binding proteins (CaBPs) such as parvalbumin are part of the cellular calcium buffering system that determines intracellular calcium diffusion and influences the spatiotemporal dynamics of calcium signals. In neurons, CaBPs are primarily localized to the cytosol and function, for example, in nerve terminals in short-term synaptic plasticity. However, CaBPs are also expressed in the cell nucleus, suggesting that they modulate nuclear calcium signals, which are key regulators of neuronal gene expression. Here we show that the calcium buffering capacity of the cell nucleus in mouse hippocampal neurons regulates neuronal architecture by modulating the expression levels of VEGFD and the complement factor C1q-c, two nuclear calcium-regulated genes that control dendrite geometry and spine density, respectively. Increasing the levels of nuclear calcium buffers by means of expression of a nuclearly targeted form of parvalbumin fused to mCherry (PV.NLS-mC) led to a reduction in VEGFD expression and, as a result, to a decrease in total dendritic length and complexity. In contrast, mRNA levels of the synapse pruning factor C1q-c were increased in neurons expressing PV.NLS-mC, causing a reduction in the density and size of dendritic spines. Our results establish a close link between nuclear calcium buffering capacity and the transcription of genes that determine neuronal structure. They suggest that the development of cognitive deficits observed in neurological conditions associated with CaBP deregulation may reflect the loss of necessary structural features of dendrites and spines. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. Calcium homeostasis in diabetes mellitus. (United States)

    Ahn, Changhwan; Kang, Ji-Houn; Jeung, Eui-Bae


    Diabetes mellitus (DM) is becoming a lifestyle-related pandemic disease. Diabetic patients frequently develop electrolyte disorders, especially diabetic ketoacidosis or nonketotic hyperglycemic hyperosmolar syndrome. Such patients show characteristic potassium, magnesium, phosphate, and calcium depletion. In this review, we discuss a homeostatic mechanism that links calcium and DM. We also provide a synthesis of the evidence in favor or against this linking mechanism by presenting recent clinical indications, mainly from veterinary research. There are consistent results supporting the use of calcium and vitamin D supplementation to reduce the risk of DM. Clinical trials support a marginal reduction in circulating lipids, and some meta-analyses support an increase in insulin sensitivity, following vitamin D supplementation. This review provides an overview of the calcium and vitamin D disturbances occurring in DM and describes the underlying mechanisms. Such elucidation will help indicate potential pathophysiology-based precautionary and therapeutic approaches and contribute to lowering the incidence of DM.

  8. Solubilities of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid in water

    Energy Technology Data Exchange (ETDEWEB)

    Mishelevich, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel); Apelblat, Alexander [Department of Chemical Engineering, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel)], E-mail:


    The solubility in water of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid was determined in the 278.15 K to 343.15 K temperature range. The solubility of these compounds served to permit the evaluation of the apparent molar enthalpies of solution.

  9. Solubilities of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid in water

    International Nuclear Information System (INIS)

    Mishelevich, Alexander; Apelblat, Alexander


    The solubility in water of magnesium-L-ascorbate, calcium-L-ascorbate, magnesium-L-glutamate, magnesium-D-gluconate, calcium-D-gluconate, calcium-D-heptagluconate, L-aspartic acid, and 3-nitrobenzoic acid was determined in the 278.15 K to 343.15 K temperature range. The solubility of these compounds served to permit the evaluation of the apparent molar enthalpies of solution

  10. Magnesium-to-calcium ratio in tap water, and its relationship to geological features and the incidence of calcium-containing urinary stones. (United States)

    Kohri, K; Kodama, M; Ishikawa, Y; Katayama, Y; Takada, M; Katoh, Y; Kataoka, K; Iguchi, M; Kurita, T


    We examined the relationship among magnesium and calcium content in tap water, the geological features and urinary stone incidence in Japan. The magnesium-to-calcium ratio in tap water correlated negatively with the incidence of urolithiasis. There was no correlation between calcium and magnesium concentration in tap water and urinary stone incidence. Geological features in Japan were classified into 5 groups. The magnesium-to-calcium ratio in the basalt areas was higher than in the other areas, while ratio in the granite areas was low. In the sedimentary rock areas calcium and magnesium concentrations were high; the magnesium-to-calcium ratio in these areas was between those of the basalt and granite areas. The limestone areas had a much higher calcium concentration. The incidence of urinary stones in the sedimentary rock and basalt areas was lower than that of the granite areas, while that in the limestone areas was the highest. Thus, the incidence of urinary stone is related to the magnesium-to-calcium ratio in tap water and the geological area.

  11. Calcium response to vitamin D supplementation

    Directory of Open Access Journals (Sweden)

    Francisco R. Spivacow


    Full Text Available Several studies show the importance of serum vitamin D sufficient levels to prevent multiple chronic diseases. However, vitamin D supplementation and its effects on urine calcium excretion remain controversial. The objective of this prospective and interventional study was to evaluate urine calcium excretion in women with normal calciuria or hypercalciuria, once serum vitamin D sufficiency was achieved. We studied 63 women with idiopathic hypercalciuria, (9 with renal lithiasis and 50 normocalciuric women. Both groups had serum vitamin D levels low (deficiency or insufficiency. Baseline urine calcium excretion was measured before being supplemented with vitamin D2 or D3 weekly or vitamin D3 100.000 IU monthly. Once serum vitamin D levels were corrected achieving at least 30 ng/ml, a second urine calcium excretion was obtained. Although in the whole sample we did not observe significant changes in urine calcium excretion according to the way of supplementation, some of those with weekly supplementation had significant higher urine calcium excretion, 19% (n = 12 of hypercalciuric women and 12% (n = 6 of the normocalciuric group. Monthly doses, also showed higher urine calcium excretion in 40% of hypercalciuric women (n = 4/10 and in 44% (n = 4/9 of the renal lithiasis hypercalciuric patients. In conclusion, different ways of vitamin D supplementation and adequate serum levels are safe in most patients, although it should be taken into account a subgroup, mainly with monthly loading doses, that could increase the calciuria significantly eventually rising renal lithiasis risk or bone mass loss, if genetically predisposed.

  12. Studies on endogenous circulating calcium entry blocker and stimulator

    International Nuclear Information System (INIS)

    Pang, P.K.T.; Yang, M.C.M.


    Several synthetic compounds have been studied extensively for their calcium entry blockade and stimulation in smooth muscles. It is hypothesized that there should be endogenous substances which control calcium entry into cells. We recently investigated the effect of some vasoactive hormones on calcium entry. Our studies on rat tail artery helical strip showed that the in vitro vasoconstriction produced by arginine vasopressin (AVP) decreased stepwise with decreasing concentration of both calcium. After exposure of the tail artery to calcium-free Ringer's solution for 1 minute or longer, the tissue lost its ability to respond to AVP. Subsequent addition of calcium to the medium produced immediate contraction. Measurements of low affinity lanthanum resistant pool of calcium with 45 Ca showed that AVP increased calcium uptake by tail artery in a dose-dependent manner. In another study rat tail artery helical strip indicated that the vasorelaxing action of parathyroid hormone (PTH) was related to an inhibition of calcium uptake. AVP or 60 mM potassium chloride increased the low affinity lanthanum resistant pool of calcium in rate tail artery and PTH inhibited the increase. In conclusion, AVP and PTH may behave like endogenous calcium entry stimulator and inhibitor respectively in vascular tissues

  13. Diagnosis and assessment of skeletal related disease using calcium 41 (United States)

    Hillegonds, Darren J [Oakland, CA; Vogel, John S [San Jose, CA; Fitzgerald, Robert L [Encinitas, CA; Deftos, Leonard J [Del Mar, CA; Herold, David [Del Mar, CA; Burton, Douglas W [San Diego, CA


    A method of determining calcium metabolism in a patient comprises the steps of administering radioactive calcium isotope .sup.41Ca to the patient, allowing a period of time to elapse sufficient for dissemination and reaction of the radioactive calcium isotope .sup.41Ca by the patient, obtaining a sample of the radioactive calcium isotope .sup.41Ca from the patient, isolating the calcium content of the sample in a form suitable for precise measurement of isotopic calcium concentrations, and measuring the calcium content to determine parameters of calcium metabolism in the patient.

  14. Preliminary characterization of calcium chemical environment in apatitic and non-apatitic calcium phosphates of biological interest by X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Eichert, D.; Salome, M.; Banu, M.; Susini, J.; Rey, C.


    Several reports have mentioned the existence of non-apatitic environments of phosphate and carbonate ions in synthetic and biological poorly crystalline apatites. However there were no direct spectroscopic evidences for the existence of non-apatitic environment of calcium ions. X-ray Absorption Spectroscopy, at the K-edge of calcium, allows the discrimination between different calcium phosphates of biological interest despite great spectral similarities. A primary analysis of the spectra reveals the existence, in synthetic poorly crystalline apatites, of variable features related to the maturation stage of the sample and corresponding to the existence of non-apatitic environments of calcium ions. Although these features can also be found in several other calcium phosphate salts, and do not allow a clear identification of the ionic environments of calcium ions, they give a possibility to directly determine the maturity of poorly crystalline apatite from calcium X-ray Absorption Near Edge Structure spectra

  15. Bell-shaped calcium-response curves of lns(l,4,5)P3- and calcium-gated channels from endoplasmic reticulum of cerebellum (United States)

    Bezprozvanny, Llya; Watras, James; Ehrlich, Barbara E.


    RELEASE of calcium from intracellular stores occurs by two pathways, an inositol 1,4,5-trisphosphate (InsP3)-gated channel1-3 and a calcium-gated channel (ryanodine receptor)4-6. Using specific antibodies, both receptors were found in Purkinje cells of cerebellum7,8. We have now compared the functional properties of the channels corresponding to the two receptors by incorporating endoplasmic reticulum vesicles from canine cerebellum into planar bilayers. InsP3-gated channels were observed most frequently. Another channel type was activated by adenine nucleotides or caffeine, inhibited by ruthenium red, and modified by ryanodine, characteristics of the ryanodine receptor/channel6. The open probability of both channel types displayed a bell-shaped curve for dependence on calcium. For the InsP3-gated channel, the maximum probability of opening occurred at 0.2 µM free calcium, with sharp decreases on either side of the maximum. Maximum activity for the ryanodine receptor/channel was maintained between 1 and 100 µM calcium. Thus, within the physiological range of cytoplasmic calcium, the InsP3-gated channel itself allows positive feed-back and then negative feedback for calcium release, whereas the ryanodine receptor/channel behaves solely as a calcium-activated channel. The existence in the same cell of two channels with different responses to calcium and different ligand sensitivities provides a basis for complex patterns of intracellular calcium regulation.

  16. Short-range intercellular calcium signaling in bone

    DEFF Research Database (Denmark)

    Jørgensen, Niklas Rye


    into biological effects in bone. Intercellular calcium waves are increases in intracellular calcium concentration in single cells, subsequently propagating to adjacent cells, and can be a possible mechanism for the coupling of bone formation to bone resorption. The aim of the present studies was to investigate...... whether bone cells are capable of communicating via intercellular calcium signals, and determine by which mechanisms the cells propagate the signals. First, we found that osteoblastic cells can propagate intercellular calcium transients upon mechanical stimulation, and that there are two principally...... different mechanisms for this propagation. One mechanism involves the secretion of a nucleotide, possibly ATP, acting in an autocrine action to purinergic P2Y2 receptors on the neighboring cells, leading to intracellular IP3 generation and subsequent release of calcium from intracellular stores. The other...

  17. Relationship of calcium absorption with 25(OH)D and calcium intake in children with rickets (United States)

    Nutritional rickets has long been considered a disease caused by vitamin D deficiency, but recent data indicate that inadequate dietary calcium intake is an important cause of rickets, particularly in tropical countries. Children with rickets due to calcium deficiency do not have very low 25(OH) D c...

  18. Eggshell powder, a comparable or better source of calcium than purified calcium carbonate: Piglet studies

    NARCIS (Netherlands)

    Schaafsma, A.; Beelen, G.M.


    Powdered chicken eggshells might be an interesting and widely available source of calcium. In two studies using piglets we determined the digestibility of calcium from different diets. The first study compared casein-based diets with CaCO3 (CasCC) or eggshell powder (CasES). The second study

  19. Calcium, snails, and birds: a case study

    Directory of Open Access Journals (Sweden)

    R. Mänd


    Full Text Available Recent studies have shown that wild birds breeding in acidified areas have difficulties with obtaining sufficient calcium for their eggshells, and that the cause of it is the shortage of land snails. Many birds have to search for Ca-rich snail shells on a daily basis during egg production. Molluscs depend on litter calcium, which has decreased due to acidification of the environment. Calcium limitation may be a widespread phenomenon also in non-acidified, naturally Ca-poor areas. The problem is that while in the latter areas the time for development of specific adaptations may have been sufficient, then in acidified areas, on the contrary, calcium shortage is a recent phenomenon. Therefore, since the extent of calcium limitation in non-acidified areas is hard to derive from observational data, experimental approach is needed. We provide experimental evidence that specific calcium deficit does affect reproductive traits also in the birds breeding in naturally base-poor habitats. Our study was conducted in a heterogeneous woodland area in Estonia containing deciduous forest patches as well as base-poor pine forest with low snail abundance. Ca supplementation, using snail shell and chicken eggshell fragments, was carried out for pied flycatchers and great tits. Extra calcium affected positively several reproductive traits like egg volume and eggshell thickness, start of breeding, and fledglings’ parameters. The negative relationship between calcium availability and lay-date suggests that birds adjust their breeding tactics to conditions of Ca deficiency, for example, by postponing laying.

  20. A comprehensive search for calcium binding sites critical for TMEM16A calcium-activated chloride channel activity (United States)

    Tien, Jason; Peters, Christian J; Wong, Xiu Ming; Cheng, Tong; Jan, Yuh Nung; Jan, Lily Yeh; Yang, Huanghe


    TMEM16A forms calcium-activated chloride channels (CaCCs) that regulate physiological processes such as the secretions of airway epithelia and exocrine glands, the contraction of smooth muscles, and the excitability of neurons. Notwithstanding intense interest in the mechanism behind TMEM16A-CaCC calcium-dependent gating, comprehensive surveys to identify and characterize potential calcium sensors of this channel are still lacking. By aligning distantly related calcium-activated ion channels in the TMEM16 family and conducting systematic mutagenesis of all conserved acidic residues thought to be exposed to the cytoplasm, we identify four acidic amino acids as putative calcium-binding residues. Alterations of the charge, polarity, and size of amino acid side chains at these sites alter the ability of different divalent cations to activate the channel. Furthermore, TMEM16A mutant channels containing double cysteine substitutions at these residues are sensitive to the redox potential of the internal solution, providing evidence for their physical proximity and solvent accessibility. DOI: PMID:24980701

  1. Vitamin D, Calcium, and Bone Health (United States)

    ... Bone Health Featured Resource Find an Endocrinologist Search Vitamin D, Calcium, and Bone Health Download PDFs English ... also helps keep your bones strong. Why are vitamin D and calcium important to bone health? Vitamin ...

  2. Properties of calcium silicate-monobasic calcium phosphate materials for endodontics containing tantalum pentoxide and zirconium oxide. (United States)

    Zamparini, Fausto; Siboni, Francesco; Prati, Carlo; Taddei, Paola; Gandolfi, Maria Giovanna


    The aim of the study was to evaluate chemical-physical properties and apatite-forming ability of three premixed calcium silicate materials containing monobasic calcium phosphate (CaH 4 P 2 O 8 ) bioceramic, tantalum pentoxide and zirconium oxide, recently marketed for endodontics (TotalFill BC-Sealer, BC-RRM-Paste, BC-RRM-Putty). Microchemical and micromorphological analyses, radiopacity, initial and final setting times, calcium release and alkalising activity were tested. The nucleation of calcium phosphates (CaPs) and/or apatite after 28 days ageing was evaluated by ESEM-EDX and micro-Raman spectroscopy. BC-Sealer and BC-RRM-Paste showed similar initial (23 h), prolonged final (52 h) setting times and good radiopacity (> 7 mm Al); BC-RRM-Putty showed fast initial (2 h) and final setting times (27 h) and excellent radiopacity (> 9 mm Al). All materials induced a marked alkalisation (pH 11-12) up to 28 days and showed the release of calcium ions throughout the entire test period (cumulative calcium release 641-806 ppm). After 28 days ageing, a well-distributed mineral layer was present on all samples surface; EDX demonstrated relevant calcium and phosphorous peaks. B-type carbonated apatite and calcite deposits were identified by micro-Raman spectroscopy on all the 28-day-aged samples; the deposit thickness was higher on BC-RRM-Paste and BC-RRM-Putty, in agreement with calcium release data. These materials met the required chemical and physical standards and released biologically relevant ions. The CaSi-CaH 4 P 2 O 8 system present in the materials provided Ca and OH ions release with marked abilities to nucleate a layer of B-type carbonated apatite favoured/accelerated by the bioceramic presence. The ability to nucleate apatite may lead many clinical advantages: In orthograde endodontics, it may improve the sealing ability by the deposition of CaPs at the material-root dentine interface, and in endodontic surgery, it could promote bone and

  3. Antagonist effects of calcium on borosilicate glass alteration

    Energy Technology Data Exchange (ETDEWEB)

    Mercado-Depierre, S. [CEA Marcoule, DTCD SPDE LCLT, 30207 Bagnols sur Cèze (France); Angeli, F., E-mail: [CEA Marcoule, DTCD SPDE LCLT, 30207 Bagnols sur Cèze (France); Frizon, F. [CEA Marcoule, DTCD SECM LP2C, 30207 Bagnols sur Cèze (France); Gin, S. [CEA Marcoule, DTCD SPDE LCLT, 30207 Bagnols sur Cèze (France)


    Graphical abstract: Display Omitted -- Highlights: •Kinetic study of glass alteration is investigated in calcium-enriched solutions. •New insights into silicon–calcium interactions in glass/cement systems are proposed. •Glass alteration is controlled by pH, Ca concentration and reaction progress. •Evidence of antagonist effects according to the importance of these parameters. -- Abstract: Numerous studies have been conducted on glass and cement durability in contact with water, but very little work to date has focused directly on interactions between the two materials. These interactions are mostly controlled by silicon–calcium reactivity. However, the physical and chemical processes involved remain insufficiently understood to predict the evolution of coupled glass–cement systems used in several industrial applications. Results are reported from borosilicate glass alteration in calcium-rich solutions. Our data show that four distinct behaviors can be expected according to the relative importance of three key parameters: the pH, the reaction progress (short- or long-term alteration) and the calcium concentration. Glass alteration is thus controlled by specific mechanisms depending on the solution chemistry: calcium complexation at the glass surface, precipitation of calcium silicate hydrates (C–S–H) or calcium incorporation in the altered layer. These findings highlight the impact of silicon–calcium interactions on glass durability and open the way for a better understanding of glass–cement mixing in civil engineering applications as well as in nuclear waste storage.

  4. Antagonist effects of calcium on borosilicate glass alteration

    International Nuclear Information System (INIS)

    Mercado-Depierre, S.; Angeli, F.; Frizon, F.; Gin, S.


    Graphical abstract: Display Omitted -- Highlights: •Kinetic study of glass alteration is investigated in calcium-enriched solutions. •New insights into silicon–calcium interactions in glass/cement systems are proposed. •Glass alteration is controlled by pH, Ca concentration and reaction progress. •Evidence of antagonist effects according to the importance of these parameters. -- Abstract: Numerous studies have been conducted on glass and cement durability in contact with water, but very little work to date has focused directly on interactions between the two materials. These interactions are mostly controlled by silicon–calcium reactivity. However, the physical and chemical processes involved remain insufficiently understood to predict the evolution of coupled glass–cement systems used in several industrial applications. Results are reported from borosilicate glass alteration in calcium-rich solutions. Our data show that four distinct behaviors can be expected according to the relative importance of three key parameters: the pH, the reaction progress (short- or long-term alteration) and the calcium concentration. Glass alteration is thus controlled by specific mechanisms depending on the solution chemistry: calcium complexation at the glass surface, precipitation of calcium silicate hydrates (C–S–H) or calcium incorporation in the altered layer. These findings highlight the impact of silicon–calcium interactions on glass durability and open the way for a better understanding of glass–cement mixing in civil engineering applications as well as in nuclear waste storage

  5. An improved kilogram-scale preparation of atorvastatin calcium. (United States)

    Novozhilov, Yuri V; Dorogov, Mikhail V; Blumina, Maria V; Smirnov, Alexey V; Krasavin, Mikhail


    If literature protocols are followed, conversion of an advanced ketal ester intermediate (available in kilogram quantities via a published Paal-Knorr synthesis) to cholesterol-lowering drug atorvastatin calcium is hampered by several process issues, particularly at the final stage where the hemi-calcium salt is obtained. We developed a high-yielding synthesis of atorvastatin calcium salt on 7 kg scale that affords >99.5% product purities by introducing the following key improvements: i. isolating the pure product of the ketal deprotection step as crystalline solid, and ii. using a convenient ethyl acetate extraction procedure to isolate the pure atorvastatin calcium at the ester hydrolysis and counter-ion exchange step. The convenient and operationally simple conversion of an advanced intermediate of atorvastatin to the clinically used hemi-calcium salt form of the drug that is superior to the methods obtainable from the literature is now available to facilitate the production of atorvastatin calcium on industrial scale. Graphical abstractStepwise ketal and tert-butyl ester group hydrolysis and a modified work-up protocol lead to a more convenient preparation of API-grade atorvastatin calcium.


    NARCIS (Netherlands)



    It is shown that heat-induced increase of intracellular calcium does not correlate with hyperthermic cell killing. Six different cell lines were investigated; in four (EAT, HeLa S3, L5178Y-R and L5178Y-S) heat treatments killing 90% of the cells did not affect the levels of intracellular free

  7. Analysis of calcium-induced conformational changes in calcium-binding allergens and quantitative determination of their IgE binding properties. (United States)

    Parody, Nuria; Fuertes, Miguel Angel; Alonso, Carlos; Pico de Coaña, Yago


    The polcalcin family is one of the most epidemiologically relevant families of calcium-binding allergens. Polcalcins are potent plant allergens that contain one or several EF-hand motifs and their allergenicity is primarily associated with the Ca(2+)-bound form of the protein. Conformation, stability, as well as IgE recognition of calcium-binding allergens greatly depend on the presence of protein-bound calcium ions. We describe a protocol that uses three techniques (SDS-PAGE, circular dichroism spectroscopy, and ELISA) to describe the effects that calcium has on the structural changes in an allergen and its IgE binding properties.

  8. Calcium and vitamin D for bone health in adults (United States)

    The calcium intake requirement is challenging to determine, and the IOM recommendations are based largely on calcium balance studies. The IOM recommends a calcium intake of 1000-1200 mg per day for older adults to support the preservation of bone mass. Food sources of calcium are preferred because h...

  9. The effect of radiopacifiers agents on pH, calcium release, radiopacity, and antimicrobial properties of different calcium hydroxide dressings. (United States)

    Ordinola-Zapata, Ronald; Bramante, Clovis Monteiro; García-Godoy, Franklin; Moldauer, Bertram Ivan; Gagliardi Minotti, Paloma; Tercília Grizzo, Larissa; Duarte, Marco Antonio Hungaro


    The aim of this study was to evaluate the antimicrobial activity, pH level, calcium ion release, and radiopacity of calcium hydroxide pastes associated with three radiopacifying agents (iodoform, zinc oxide, and barium sulfate). For the pH and calcium release tests, 45 acrylic teeth were utilized and immersed in ultrapure water. After 24 h, 72 h, and 7 days the solution was analyzed by using a pH meter and an atomic absorption spectrophotometer. Polyethylene tubes filled with the pastes were used to perform the radiopacity test. For the antimicrobial test, 25 dentin specimens were infected intraorally in order to induce the biofilm colonization and treated with the pastes for 7 days. The Live/Dead technique and a confocal microscope were used to obtain the ratio of live cells. Parametric and nonparametric statistical tests were performed to show differences among the groups (P calcium release test on the 7th day (P > 0.05). The calcium hydroxide/iodoform samples had the highest radiopacity and antimicrobial activity against the biofilm-infected dentin in comparison to the other pastes (P Calcium hydroxide mixed with 17% iodoform and 35% propylene glycol into a paste had the highest pH, calcium ion release, radiopacity, and the greatest antimicrobial action versus similar samples mixed with BaSO4 or ZnO. © 2015 Wiley Periodicals, Inc.

  10. First Quantification of Calcium Intake from Calcium-Dense Dairy Products in Dutch Fracture Patients (The Delft Cohort Study)


    van den Berg, Peter; van Haard, Paul M. M.; van den Bergh, Joop P. W.; Niesten, Dieu Donné; van der Elst, Maarten; Schweitzer, Dave H.


    Recommendations for daily calcium intake from dairy products are variable and based on local consensus. To investigate whether patients with a recent fracture complied with these recommendations, we quantified the daily dairy calcium intake including milk, milk drinks, pudding, yoghurt, and cheese in a Dutch cohort of fracture patients and compared outcomes with recent data of a healthy U.S. cohort (80% Caucasians). An observational study analyzed dairy calcium intakes of 1526 female and 372 ...

  11. Retention of zinc and calcium from the human colon

    International Nuclear Information System (INIS)

    Sandstroem, B.C.; Cederblad, A.; Kivistoe, B.S.; Stenquist, B.; Andersson, H.


    Colonic retention of zinc and calcium was studied after installation during colonoscopy of 30 mumol of zinc and 6.4 mmol of calcium labeled with 65 Zn and 47 Ca, and measurement of the whole-body retention of the radionuclides. After cecal installation in nine patients, retention (day 13) of zinc was 3.5 +/- 2.1% (mean +/- SD) and of calcium 3.5 +/- 2.7%. The calculated mean absorption was 4.1% for zinc and 14.1% for calcium. Application at the hepatic flexure in four patients resulted in a mean retention (day 13) of 1.2% for zinc and 0.6% for calcium. Under prevailing conditions, colonic absorption of zinc is relatively small, compared to the uptake after oral administration. Colonic absorption of calcium could, however, account for a substantial part of the total calcium uptake

  12. Deposition of strontium and calcium in snail shell

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, Jr, G M; Nelson, D J; Gardiner, D A


    The relative effects of strontium and calcium concentrations in the environment on their uptake and incorporation into snail shell were investigated. /sup 45/Ca and /sup 85/Sr were used as tracers and specific activities were used to determine deposition. Data are presented in tables and graphs. Deposition of both calcium and strontium in the snail shell depended primarily on the respective concentrations of these elements in the immediate environment. A slight effect of strontium on calcium deposition was observed. There was found to be a minimum strontium deposition for various combinations of strontium and calcium in the environment. It was concluded that strontium uptake is more closely associated with environmental strontium concentrations than with calcium concentrations.

  13. Oligofructose stimulates calcium absorption in adolescents

    NARCIS (Netherlands)

    Heuvel, E.G.H.M. van den; Muys, T.; Dokkum, W. van; Schaafsma, G.


    Background: In rats, nondigestible oligosaccharides stimulate calcium absorption. Recently, this effect was also found in human subjects. Objective: The objective of the study was to investigate whether consumption of 15 g oligofructose/d stimulates calcium absorption in male adolescents. Design:

  14. Models of calcium signalling

    CERN Document Server

    Dupont, Geneviève; Kirk, Vivien; Sneyd, James


    This book discusses the ways in which mathematical, computational, and modelling methods can be used to help understand the dynamics of intracellular calcium. The concentration of free intracellular calcium is vital for controlling a wide range of cellular processes, and is thus of great physiological importance. However, because of the complex ways in which the calcium concentration varies, it is also of great mathematical interest.This book presents the general modelling theory as well as a large number of specific case examples, to show how mathematical modelling can interact with experimental approaches, in an interdisciplinary and multifaceted approach to the study of an important physiological control mechanism. Geneviève Dupont is FNRS Research Director at the Unit of Theoretical Chronobiology of the Université Libre de Bruxelles;Martin Falcke is head of the Mathematical Cell Physiology group at the Max Delbrück Center for Molecular Medicine, Berlin;Vivien Kirk is an Associate Professor in the Depar...

  15. Vitamin D, Calcium, or Combined Supplementation for the Primary Prevention of Fractures in Community-Dwelling Adults: Evidence Report and Systematic Review for the US Preventive Services Task Force. (United States)

    Kahwati, Leila C; Weber, Rachel Palmieri; Pan, Huiling; Gourlay, Margaret; LeBlanc, Erin; Coker-Schwimmer, Manny; Viswanathan, Meera


    Osteoporotic fractures result in significant morbidity and mortality. To update the evidence for benefits and harms of vitamin D, calcium, or combined supplementation for the primary prevention of fractures in community-dwelling adults to inform the US Preventive Services Task Force. PubMed, EMBASE, Cochrane Library, and trial registries through March 21, 2017; references; and experts. Surveillance continued through February 28, 2018. English-language randomized clinical trials (RCTs) or observational studies of supplementation with vitamin D, calcium, or both among adult populations; studies of populations that were institutionalized or had known vitamin D deficiency, osteoporosis, or prior fracture were excluded. Dual, independent review of titles/abstracts and full-text articles and study quality rating using predefined criteria. Random-effects meta-analysis used when at least 3 similar studies were available. Incident fracture, mortality, kidney stones, cardiovascular events, and cancer. Eleven RCTs (N = 51 419) in adults 50 years and older conducted over 2 to 7 years were included. Compared with placebo, supplementation with vitamin D decreased total fracture incidence (1 RCT [n = 2686]; absolute risk difference [ARD], -2.26% [95% CI, -4.53% to 0.00%]) but had no significant association with hip fracture (3 RCTs [n = 5496]; pooled ARD, -0.01% [95% CI, -0.80% to 0.78%]). Supplementation using vitamin D with calcium had no effect on total fracture incidence (1 RCT [n = 36 282]; ARD, -0.35% [95% CI, -1.02% to 0.31%]) or hip fracture incidence (2 RCTs [n = 36 727]; ARD from the larger trial, -0.14% [95% CI, -0.34% to 0.07%]). The evidence for calcium alone was limited, with only 2 studies (n = 339 total) and very imprecise results. Supplementation with vitamin D alone or with calcium had no significant effect on all-cause mortality or incident cardiovascular disease; ARDs ranged from -1.93% to 1.79%, with CIs consistent with no

  16. Intact calcium signaling in adrenergic-deficient embryonic mouse hearts. (United States)

    Peoples, Jessica N; Taylor, David G; Katchman, Alexander N; Ebert, Steven N


    Mouse embryos that lack the ability to produce the adrenergic hormones, norepinephrine (NE) and epinephrine (EPI), due to disruption of the dopamine beta-hydroxylase (Dbh -/- ) gene inevitably perish from heart failure during mid-gestation. Since adrenergic stimulation is well-known to enhance calcium signaling in developing as well as adult myocardium, and impairments in calcium signaling are typically associated with heart failure, we hypothesized that adrenergic-deficient embryonic hearts would display deficiencies in cardiac calcium signaling relative to adrenergic-competent controls at a developmental stage immediately preceding the onset of heart failure, which first appears beginning or shortly after mouse embryonic day 10.5 (E10.5). To test this hypothesis, we used ratiometric fluorescent calcium imaging techniques to measure cytosolic calcium transients, [Ca 2+ ] i in isolated E10.5 mouse hearts. Our results show that spontaneous [Ca 2+ ] i oscillations were intact and robustly responded to a variety of stimuli including extracellular calcium (5 mM), caffeine (5 mM), and NE (100 nM) in a manner that was indistinguishable from controls. Further, we show similar patterns of distribution (via immunofluorescent histochemical staining) and activity (via patch-clamp recording techniques) for the major voltage-gated plasma membrane calcium channel responsible for the L-type calcium current, I Ca,L , in adrenergic-deficient and control embryonic cardiac cells. These results demonstrate that despite the absence of vital adrenergic hormones that consistently leads to embryonic lethality in vivo, intracellular and extracellular calcium signaling remain essentially intact and functional in embryonic mouse hearts through E10.5. These findings suggest that adrenergic stimulation is not required for the development of intracellular calcium oscillations or extracellular calcium signaling through I Ca,L and that aberrant calcium signaling does not likely contribute

  17. Calcium binding to low molecular weight compounds and health promoting products

    DEFF Research Database (Denmark)

    Vavrusova, Martina

    absorption. Therefore, calcium as an essential nutrient should not be underestimated in our diet. Milk and dairy products are good sources of bioavailable calcium due to specific protein binding. Other sources of calcium, apart from a balanced and healthy diet, are calcium supplements and calcium fortified...... food. Therefore, an understanding of the basic chemistry of calcium binding to low molecular weight compounds can contribute to a general knowledge about calcium bioavailability and also to product improvement. Calcium precipitation with palmitate was described by a first-order reaction for conditions...... of excess calcium in neutral aqueous solutions with a stoichiometry Ca:Pal lower than 1:2. Increasing pH during aging of the precipitate and solubility product determination lead to a suggestion of an initial precipitation of calcium hydroxy palmitate as a possible precursor phase. The binding of calcium...

  18. Electrophysical properties of calcium vanadates

    International Nuclear Information System (INIS)

    Krasnenko, T.I.; Fotiev, A.A.


    Electrophysical properties of calcium vanadates are studied for the case of alteration of external parameters of the medium (PO 2 , T). It is lshown that structural transformations bring about changes in the nature of electrophysical properties of Ca 2 V 2 O 7 , Ca 3 (VO 4 ) 2 , this being the reason for charge redistribution in anion groupings. It is obvious, that the general conductivity of calcium methavanadate is mainly caused by ion transport. Ca(VO 3 ) 2 possesses amphoteric character of semiconducting properties: the type of conductivity changes from ''p'' to ''n'' with temperature increase. Polytherms of conductivity and sums of ion numbers of Ca 2 V 2 O 7 transition are given. It is established that calcium pyrovanadate has a mixed electron-ion conductivity

  19. Effect of zinc supplements on the intestinal absorption of calcium

    International Nuclear Information System (INIS)

    Spencer, H.; Rubio, N.; Kramer, L.; Norris, C.; Osis, D.


    Pharmacologic doses of zinc are widely used as zinc supplements. As calcium and zinc may compete for common absorption sites, a study was carried out on the effect of a pharmacologic dose of zinc on the intestinal absorption of calcium in adult males. The analyzed dietary zinc intake in the control studies was normal, averaging 14.6 mg/day. During the high zinc study, 140 mg zinc as the sulfate was added daily for time periods ranging from 17 to 71 days. The studies were carried out during both a low calcium intake averaging 230 mg/day and during a normal calcium intake of 800 mg/day. Calcium absorption studies were carried out during the normal and high zinc intake by using an oral tracer dose of Ca-47 and determining plasma levels and urinary and fecal excretions of Ca-47. The study has shown that, during zinc supplementation, the intestinal absorption of calcium was significantly lower during a low calcium intake than in the control study, 39.3% vs 61% respectively, p less than 0.001. However, during a normal calcium intake of 800 mg/day, the high zinc intake had no significant effect on the intestinal absorption of calcium. These studies have shown that the high zinc intake decreased the intestinal absorption of calcium during a low calcium intake but not during a normal calcium intake

  20. 21 CFR 172.715 - Calcium lignosulfonate. (United States)



  1. In vivo calcium metabolism by IRMS (United States)

    Public policy initiatives related to enhancing the health of populations, increasingly seek to identify meaningful biological outcomes on which to determine age-related nutritional requirements. For calcium, the primary outcome of interest is the availability of calcium in the diet for bone formatio...

  2. Calcium - urine (United States)

    ... Female urinary tract Male urinary tract Calcium urine test References Bringhurst FR, Demay MB, Kronenberg HM. Hormones and disorders of mineral metabolism. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology . 13th ed. Philadelphia, PA: Elsevier; ...

  3. Calcium-dependent but calmodulin-independent protein kinase from soybean

    International Nuclear Information System (INIS)

    Harmon, A.C.; Putnam-Evans, C.; Cormier, M.J.


    A calcium-dependent protein kinase activity from suspension-cultured soybean cells (Glycine max L. Wayne) was shown to be dependent on calcium but not calmodulin. The concentrations of free calcium required for half-maximal histone H1 phosphorylation and autophosphorylation were similar (≥ 2 micromolar). The protein kinase activity was stimulated 100-fold by ≥ 10 micromolar-free calcium. When exogenous soybean or bovine brain calmodulin was added in high concentration (1 micromolar) to the purified kinase, calcium-dependent and -independent activities were weakly stimulated (≤ 2-fold). Bovine serum albumin had a similar effect on both activities. The kinase was separated from a small amount of contaminating calmodulin by sodium dodecyl sulfate polyacrylamide gel electrophoresis. After renaturation the protein kinase autophosphorylated and phosphorylated histone H1 in a calcium-dependent manner. Following electroblotting onto nitrocellulose, the kinase bound 45 Ca 2+ in the presence of KCl and MgCl 2 , which indicated that the kinase itself is a high-affinity calcium-binding protein. Also, the mobility of one of two kinase bands in SDS gels was dependent on the presence of calcium. Autophosphorylation of the calmodulin-free kinase was inhibited by the calmodulin-binding compound N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7), showing that the inhibition of activity by W-7 is independent of calmodulin. These results show that soybean calcium-dependent protein kinase represents a new class of protein kinase which requires calcium but not calmodulin for activity

  4. 36 CFR 223.36 - Volume determination. (United States)


    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Volume determination. 223.36... Volume determination. (a) Timber sale contracts may provide for volume determination by scaling... the contract or permit provides for the determination of volume by tree measurement and the timber has...

  5. Interaction of bovine gallbladder mucin and calcium-binding protein: effects on calcium phosphate precipitation. (United States)

    Afdhal, N H; Ostrow, J D; Koehler, R; Niu, N; Groen, A K; Veis, A; Nunes, D P; Offner, G D


    Gallstones consist of calcium salts and cholesterol crystals, arrayed on a matrix of gallbladder mucin (GBM), and regulatory proteins like calcium-binding protein (CBP). To determine if interactions between CBP and GBM follow a biomineralization scheme, their mutual binding and effects on CaHPO4 precipitation were studied. Binding of CBP to GBM was assessed by inhibition of the fluorescence of the complex of GBM with bis-1,8-anilinonaphthalene sulfonic acid (bis-ANS). The effects of the proteins on precipitation of CaHPO4 were assessed by nephelometry and gravimetry. Precipitates were analyzed for calcium, phosphate, and protein. CBP and bis-ANS competitively displaced each other from 30 binding sites on mucin, with a 1:1 stoichiometry and similar affinity. The rate of precipitation of CaHPO4 was retarded by mucin and CBP. Precipitate mass was unaffected by GBM alone but decreased with the addition of CBP. Complexing CBP with GBM abolished or moderated this latter effect, altered precipitate morphology, and changed the stoichiometric ratios of Ca to PO4 in the precipitates from 1:1 to 3:2. Mucin and CBP were incorporated into the precipitates. These studies suggest that the formation of calcium-containing gallstones is a biomineralization process regulated by both GBM and CBP.

  6. Calcium oxalate contribution to calcium cycling in forests of contrasting nutrient status (United States)

    Dauer, Jenny M.; Perakis, Steven S.


    Calcium oxalate (Ca oxalate) is an insoluble biomineral that forms in plants and fungi, and occurs in soils across many types of ecosystems. Assessing how Ca oxalate may shape ecosystem Ca cycling requires information on the distribution of Ca oxalate among plant biomass, detritus, and mineral soil, and how it varies with ecosystem Ca status. We compared two Douglas-fir forests of contrasting ecosystem Ca availability, and found that Ca oxalate was partitioned similarly among plant biomass, detritus and mineral soil major ecosystem compartments at both sites, and total pools of Ca oxalate were greater in the high-Ca forest. However, the proportional importance of Ca oxalate was greater in the low-Ca than high-Ca forest (18% versus 4% of actively cycling ecosystem Ca, respectively). And calcium oxalate in mineral soil, which is of particular interest as a potential long-term Ca reservoir, was a larger portion of total available Ca (exchangeable Ca plus Ca oxalate Ca) in the low-Ca site than the high-Ca site (9% versus 1% of available soil Ca, respectively). Calcium oxalate was the dominant form of Ca returned from plants to soil as leaf litterfall at the high-Ca site, yet calcium oxalate disappeared rapidly from decomposing litter (0.28 yr−1 or faster) at both sites. We conclude that accumulation of Ca oxalate in forest ecosystems appears most closely related to overall Ca supply for live biomass pools, and that the accumulation of Ca oxalate in forest floor and mineral soil is limited by rapid microbial degradation of putatively unavailable Ca oxalate.

  7. Mortar and concrete based on calcium sulphate binders

    NARCIS (Netherlands)

    Bakker, J.J.F.; Brouwers, H.J.H.; Fischer, H.B


    In this study both hemi-hydrate and anhydrite are tested as calcium sulphate binders for structural mortar and concrete. The advantage of using calcium sulphates instead of cement as a binder is the fact that the production of calcium sulphate is more environmental friendly than that of cement. For

  8. Effect of lactose on intestinal absorption of calcium; Effet du lactose sur l'absorption intestinale du calcium

    Energy Technology Data Exchange (ETDEWEB)

    Labat, Marie-Louise


    Calcium absorption was immediately increased when lactose was administered in large amounts in the intestine of standard rats fed on a vitamin D diet. The same effect could be reproduced with lactulose, a glucid un-hydrolyzed by lactase and unabsorbed. The occurrence of a saturation process for high doses of calcium agrees with a biochemical process through a carrier; this process was not inhibited by actinomycin D, which does not agree with a 'de novo' synthesis of a calcium binding protein; yet activation of the preexisting protein cannot be excluded. The intestinal effect of lactose resulted in an inhibition of bone catabolism in the adult normocalcemic rat indicating a possible interference of thyrocalcitonin. Finally in the young rat, hypocalcemic by lack of vitamin D, on account of the lactose effect, calcium can be considered as a 'third messenger' in the chain of intracellular events between the interaction of the parathyroid hormone with the bone receptor and the expression of its activity. (author) [French] Le lactose introduit en quantite importante dans l'intestin augmente immediatement l'absorption du calcium chez le rat normal recevant par ailleurs de la vitamine D. Cet effet peut etre reproduit par le lactulose, glucide non hydrolyse par la lactase et non absorbe. L'apparition d'un phenomene de saturation pour les doses elevees de calcium s'accorde avec un mecanisme biochimique mettant en jeu un transporteur. Ce mecanisme n'est pas inhibe par l'actinomycine D, ce qui ne s'accorde pas avec une synthese 'de novo' de proteine transporteuse liant le calcium; on ne peut toutefois exclure une activation de cette proteine preexistante. L'effet intestinal du lactose a pour consequence l'inhibition du catabolisme osseux chez le rat adulte normocalcemique; ceci pose le probleme d'une intervention eventuelle de la thyrocalcitonine. Enfin, l'effet lactose nous permet d'attribuer au calcium le role de 'troisieme messager' dans la chaine d

  9. Sensory analysis of calcium-biofortified lettuce (United States)

    Vegetables represent an attractive means of providing increased calcium nutrition to the public. In this study, it was demonstrated that lettuce expressing the deregulated Arabidopsis H(+)/Ca(2+) transporter sCAX1 (cation exchanger 1) contained 25-32% more calcium than controls. These biofortified l...

  10. Phagocytosis-induced /sup 45/calcium efflux in polymorphonuclear leucocytes

    Energy Technology Data Exchange (ETDEWEB)

    Barthelemy, A; Schell-Frederick, E [Brussels Univ. (Belgium). Institut de Recherche Interdisciplinaire; Paridaens, R [Brussels Univ. (Belgium). Faculte de Medicine


    The role of calcium ions in regulating the structure and function of non-muscle cells is a subject of intense study. Several lines of evidence that calcium may be essential in the function of polymorphonuclear leuocytes (PMNL) and an important control element in the process of phagocytosis. Direct studies of calcium distribution and fluxes have only recently been undertaken. To our knowledge, no report of calcium movements during normal phagocytosis has been published. In the context of an overall study of calcium dynamics in the PMNL, we report here initial studies on /sup 45/Ca efflux in prelabelled guinea pig PMNL. The results demonstrate the energy-dependence of resting calcium efflux and an increased efflux upon addition of phagocytic particles which is not dependent on particle internalization.

  11. Angiotensin effects on calcium and steroidogenesis in adrenal glomerulosa cells

    International Nuclear Information System (INIS)

    Elliott, M.E.; Siegel, F.L.; Hadjokas, N.E.; Goodfriend, T.L.


    We investigated the role of cellular calcium pools in angiotensin II-stimulated aldosterone synthesis in bovine adrenal glomerulosa cells. Angiotensin II decreased the size of the exchangeable cell calcium pool by 34%, consistent with previous observations that angiotensin II causes decreased uptake of 45 Ca+2 into cells and increased efflux of 45 Ca+2 from preloaded cells. Atomic absorption spectroscopy showed that angiotension II caused a decrease of 21% in total cellular calcium. Angiotensin II caused efflux of 45 Ca+2 in the presence of EGTA and retarded uptake of 45 Ca+2 when choline was substituted for sodium, suggesting that hormone effects on calcium pools do not involve influx of trigger calcium or sodium. Cells incubated in calcium-free buffer and 0.1 mM or 0.5 mM EGTA synthesized reduced (but still significant) amounts of the steroid in response to hormone. Cells incubated in increasing concentrations of extracellular calcium contained increasing amounts of intracellular calcium and synthesized increasing amounts of aldosterone in response to angiotensin II. These results point to the participation of intracellular calcium pools in angiotensin II-stimulated steroidogenesis and the importance of extracellular calcium in maintaining these pools

  12. The Function of the Mitochondrial Calcium Uniporter in Neurodegenerative Disorders

    Directory of Open Access Journals (Sweden)

    Yajin Liao


    Full Text Available The mitochondrial calcium uniporter (MCU—a calcium uniporter on the inner membrane of mitochondria—controls the mitochondrial calcium uptake in normal and abnormal situations. Mitochondrial calcium is essential for the production of adenosine triphosphate (ATP; however, excessive calcium will induce mitochondrial dysfunction. Calcium homeostasis disruption and mitochondrial dysfunction is observed in many neurodegenerative disorders. However, the role and regulatory mechanism of the MCU in the development of these diseases are obscure. In this review, we summarize the role of the MCU in controlling oxidative stress-elevated mitochondrial calcium and its function in neurodegenerative disorders. Inhibition of the MCU signaling pathway might be a new target for the treatment of neurodegenerative disorders.

  13. Activation of L-type calcium channels is required for gap junction-mediated intercellular calcium signaling in osteoblastic cells

    DEFF Research Database (Denmark)

    Jørgensen, Niklas Rye; Teilmann, Stefan Cuoni; Henriksen, Zanne


    The propagation of mechanically induced intercellular calcium waves (ICW) among osteoblastic cells occurs both by activation of P2Y (purinergic) receptors by extracellular nucleotides, resulting in "fast" ICW, and by gap junctional communication in cells that express connexin43 (Cx43), resulting...... in "slow" ICW. Human osteoblastic cells transmit intercellular calcium signals by both of these mechanisms. In the current studies we have examined the mechanism of slow gap junction-dependent ICW in osteoblastic cells. In ROS rat osteoblastic cells, gap junction-dependent ICW were inhibited by removal...... of extracellular calcium, plasma membrane depolarization by high extracellular potassium, and the L-type voltage-operated calcium channel inhibitor, nifedipine. In contrast, all these treatments enhanced the spread of P2 receptor-mediated ICW in UMR rat osteoblastic cells. Using UMR cells transfected to express Cx...

  14. Diagram of Calcium Movement in the Human Body (United States)


    This diagram shows the normal pathways of calcium movement in the body and indicates changes (green arrows) seen during preliminary space flight experiments. Calcium plays a central role because 1) it gives strength and structure to bone and 2) all types of cells require it to function normally. To better understand how and why weightlessness induces bone loss, astronauts have participated in a study of calcium kinetics -- that is, the movement of calcium through the body, including absorption from food, and its role in the formation and breakdown of bone.

  15. Comparative evaluation of calcium hypochlorite and sodium hypochlorite on soft-tissue dissolution. (United States)

    Dutta, Arindam; Saunders, William P


    The aim of this study was to compare in vitro the tissue-dissolution properties of 5% and 10% calcium hypochlorite (Ca(OCl)(2)) with two concentrations (1.36% and 4.65%) of proprietary sodium hypochlorite (NaOCl) on bovine muscle tissue. The available chlorine concentration of each solution was determined using iodometric titration. Tissue specimens from bovine muscle were weight adjusted (50 ± 5 mg). Ten tissue specimens in each group were immersed in 5 mL each test solution, removed after 5 minutes, blotted dry, and weighed. The process was repeated every 5 minutes with a fresh 5-mL aliquot of the test solution for 60 minutes or until complete tissue dissolution, whichever was quickest. The percentage weight loss of the specimens was calculated over the experimental period. Available chlorine concentrations of the irrigants ranged from 1.36% to 4.65%. All solutions dissolved tissue completely after 60 minutes except 5% Ca(OCl)(2) (99.4% dissolution). Between the 35- and 60-minute test readings, there were no significant differences between the solutions. Chlorax (4.65% NaOCl) (Cerkamed Group, Nisko, Poland) dissolved tissue quicker during the first 35 minutes (P Tesco bleach (1.36% NaOCl) (Tesco Stores Ltd, Chestnut, UK) in the first 35 minutes except at the 5-minute measurement. Within the limitations of this study, Chlorax (4.65% NaOCl) dissolved tissue faster than the Ca(OCl)(2) solutions and Tesco thin bleach (1.36% NaOCl) over the first 35 minutes, but there were no significant differences among the solutions thereafter. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  16. Calcium Channel Blockers (United States)

    ... Certain calcium channel blockers interact with grapefruit products. Kaplan NM, et al. Treatment of hypertension: Drug therapy. In: Kaplan's Clinical Hypertension. 11th ed. Philadelphia, Pa.: Wolters Kluwer ...

  17. The Relation between Calcium Supplement Consumption and Calcific Shoulder Tendonitis

    Directory of Open Access Journals (Sweden)

    Alireza Rouhani


    Full Text Available Background: Calcific tendonitis is a common cause of non-traumatic shoulder pain. Previous studies have suggested a relation between minerals and endocrine and calcium deposition. Thus, hypercalcemia is probably related to calcific tendonitis. This study aims at evaluating the relation found between calcium supplement consumption and calcific shoulder tendonitis. Methods: This analytical-descriptive study was conducted on 250 patients with shoulder pain referring to clinics and emergency department of Shohada Orthopedics Hospital during one year for considering calcific shoulder tendonitis and calcium supplement consumption. Patients with calcific tendonitis were treated and their functional ability was evaluated using DASH questionnaire, pain severity and range of motion (ROM before and after treatment and their correlation with calcium supplement consumption. Results: Calcific tendonitis and calcium consumption were generally seen in 30 (12% and 73 (29.2% cases, respectively. Calcium consumption frequency in patients with calcific tendonitis was significantly higher than the patients who did not consume calcium supplements (76.7% vs. 22.7%. Patients with calcific tendonitis who did not consume calcium supplements suffered from significantly longer periods of shoulder pain. All patients having consumed calcium supplement were female. The group who consumed calcium supplement had significantly severe pain and higher DASH score before and after treatment, while there was no significant difference in number of impaired ROM before and after treatment. Also, there was a negative correlation between calcium supplement consumption, pain severity and DASH score before and after treatment. Conclusion: Calcium supplement consumption is related to calcific tendonitis and is also accompanied with more pain and lower functional ability in patients with calcific tendonitis.    Keywords: Calcific tendonitis; Shoulder; Calcium supplement; Pain

  18. 21 CFR 872.3250 - Calcium hydroxide cavity liner. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

  19. Enhanced expression of a calcium-dependent protein kinase

    Indian Academy of Sciences (India)

    Among the downstream targets of calcium in plants, calcium-dependent protein kinases (CDPKs) form an interesting class of kinases which are activated by calcium binding. They have been implicated in a diverse array of responses to hormonal and environmental stimuli. In order to dissect the role of CDPKs in the moss ...

  20. Research of pharmacokinetics of L-threonate calcium with 45Ca radiotrace

    International Nuclear Information System (INIS)

    Tong Jian; Niu Huisheng; Li Huaifen


    The pharmacokinetics of calcium in L-threonate calcium is studied by radiotrace method. The results show the relationship between drug-time curve, pharmacokinetics parameters and dosage are positive correlation, and calcium distributes in important tissues such as stomach, intestines, blood and bone. In 24 hours, about 40% calcium is drained in urine, 30% calcium is evacuated in feces, 10%-20% calcium deposit in blood or bone. The radiotrace method is a kind of special, sensitive, accurate method of testing calcium metabolism

  1. Obtainment of calcium carbonate from mussels shell

    International Nuclear Information System (INIS)

    Hamester, M.R.R.; Becker, D.


    The mussels and oyster shell are discarded at environment, and this accumulation is causing negative consequences to ecosystem. Calcium carbonate is main constituent of the shell chemical composition. Aiming to reduce environmental aggression and generate income to shellfish producer, there was the possibility of using these shells as an alternative to commercial calcium carbonate. For this physics, chemicals and thermal properties were evaluated, using X-ray fluorescence, thermogravimetric analysis, size distribution, abrasiveness and scanning electronic microscopy. The results indicate that mussels shells have an initial degradation temperature higher than commercial calcium carbonate e same lost weight behavior and 95% of shell chemical composition is calcium carbonate. The sample size distribution was influenced by grinding condition and time as well as its abrasiveness. (author)

  2. Calcium and Vitamin D Supplementation in Men

    Directory of Open Access Journals (Sweden)

    Evelien Gielen


    Full Text Available Calcium and vitamin D supplements reverse secondary hyperparathyroidism and are widely prescribed to prevent osteoporotic fractures, with proven antifracture efficacy when targeted to individuals with documented insufficiencies. Men who should particularly be considered for calcium and vitamin D supplements include elderly or institutionalized individuals, patients with documented osteoporosis on antiresorptive or anabolic medication, and individuals receiving glucocorticoids. Benefits are most apparent when a daily dose of 1000–1200 mg calcium is complemented with 800 IU vitamin D. Compliance is the key to optimizing clinical efficacy. While (conventionally dosed vitamin D has not been associated with safety concerns, recent meta-analytic data have provided evidence to suggest that calcium supplements (without coadministered vitamin D may potentially be associated with cardiovascular risks.

  3. Effect of the calcium to phosphorus ratio on the setting properties of calcium phosphate bone cements. (United States)

    Vlad, M D; Gómez, S; Barracó, M; López, J; Fernández, E


    α-Tricalcium phosphate (α-TCP) has become the main reactant of most experimental and commercial ceramic bone cements. It has calcium-to-phosphorus (Ca/P) ratio of 1.50. The present study expands and reports on the microstructures and mechanical properties of calcium phosphate (CP) cements containing sintered monolithic reactants obtained in the interval 1.29 properties as well as on their microstructure and crystal phase evolution. The results showed that: (a) CP-cements made with reactants with Ca/P ratio other than 1.50 have longer setting and lower hardening properties; (b) CP-cements reactivity was clearly affected by the Ca/P ratio of the starting reactant; (c) reactants with Ca/P calcium pyrophosphate and α- and β-TCP. Similarly, reactants with Ca/P > 1.50 were composed of α-TCP, tetracalcium phosphate and hydroxyapatite; (d) only the reactant with Ca/P = 1.50 was monophasic and was made of α-TCP, which transformed during the setting into calcium deficient hydroxyapatite; (e) CP-cements developed different crystal microstructures with specific features depending on the Ca/P ratio of the starting reactant.

  4. Calcium mobilization in HeLa cells induced by nitric oxide. (United States)

    Huang, Yimei; Zheng, Liqin; Yang, Hongqin; Chen, Jiangxu; Wang, Yuhua; Li, Hui; Xie, Shusen


    Nitric oxide (NO) has been proposed to be involved in tumor growth and metastasis. However, the mechanism by which nitric oxide modulates cancer cell growth and metastasis on cellular and molecular level is still not fully understood. This work utilized confocal microscopy and fluorescence microplate reader to investigate the effects of exogenous NO on the mobilization of calcium, which is one of the regulators of cell migration, in HeLa cells. The results show that NO elevates calcium in concentration-dependent manner in HeLa cells. And the elevation of calcium induced by NO is due to calcium influx and calcium release from intracellular calcium stores. Moreover, calcium release from intracellular stores is dominant. Furthermore, calcium release from mitochondria is one of the modulation pathways of NO. These findings would contribute to recognizing the significance of NO in cancer cell proliferation and metastasis. © Wiley Periodicals, Inc.

  5. Preparation, physical-chemical characterisation and cytocompatibility of calcium carbonate cements. (United States)

    Combes, C; Miao, Baoji; Bareille, Reine; Rey, Christian


    The feasibility of calcium carbonate cements involving the recrystallisation of metastable calcium carbonate varieties has been demonstrated. Calcium carbonate cement compositions presented in this paper can be prepared straightforwardly by simply mixing water (liquid phase) with two calcium carbonate phases (solid phase) which can be easily obtained by precipitation. An original cement composition was obtained by mixing amorphous calcium carbonate and vaterite with an aqueous medium. The cement set and hardened within 2h at 37 degrees C in an atmosphere saturated with water and the final composition of the cement consisted mostly of aragonite. The hardened cement was microporous and showed poor mechanical properties. Cytotoxicity tests revealed excellent cytocompatibility of calcium carbonate cement compositions. Calcium carbonates with a higher solubility than the apatite formed for most of the marketed calcium phosphate cements might be of interest to increase biomedical cement resorption rates and to favour its replacement by bone tissue.

  6. Preparation, physical-chemical characterisation and cytocompatibility of calcium carbonate cements


    Combes, Christèle; Miao, Baoji; Bareille, Reine; Rey, Christian


    The feasibility of calcium carbonate cements involving the recrystallisation of metastable calcium carbonate varieties has been demonstrated. Calcium carbonate cement compositions presented in this paper can be prepared straightforwardly by simply mixing water (liquid phase) with two calcium carbonate phases (solid phase) which can be easily obtained by precipitation. An original cement composition was obtained by mixing amorphous calcium carbonate and vaterite with an aqueous medium. The cem...

  7. Kinetics of the Carbonate Leaching for Calcium Metavanadate

    Directory of Open Access Journals (Sweden)

    Peiyang Shi


    Full Text Available The sodium salt roasting process was widely used for extracting vanadium due to its high yield rate of vanadium. However, the serious pollution was a problem. The calcium roasting process was environmentally friendly, but the yield rate of vanadium was relatively lower. Focusing on the calcium metavanadate produced in the calcium roasting process of vanadium minerals, the mechanism of the carbonate leaching for calcium metavanadate and its leaching kinetics of calcium metavanadate were studied. With the increase of the leaching agent content, the decrease of the particle size, the increase of the temperature and the increase of the reaction time, the leaching rate of vanadium increased, and the constant of reaction rate increased. In the carbonate leaching process, the calcium carbonate was globular and attached to the surface of calcium metavanadate. In the solution containing bicarbonate radical, lots of cracks formed in the dissolution process. However, the cracks were relatively fewer in the solution containing carbonate. In the present study, the carbonate leaching for calcium metavanadate was controlled by diffusion, the activation energy reached maximum and minimum in the sodium bicarbonate and the sodium carbonate solution, respectively. The activation energy value in the ammonium bicarbonate solution was between those two solutions. The kinetic equations of the carbonate leaching for calcium metavanadate were as follows: 1 − 2/3η − (1 − η2/3 = 4.39[Na2CO3]0.75/r0 × exp(−2527.06/Tt; 1 − 2/3η − (1 − η2/3 = 7.89[NaHCO3]0.53/r0 × exp(−2530.67/Tt; 1 − 2/3η − (1 − η2/3 = 6.78[NH4HCO3]0.69/r0 × exp(−2459.71/Tt.

  8. Synthesis and properties of Asante Calcium Red--a novel family of long excitation wavelength calcium indicators. (United States)

    Hyrc, Krzysztof L; Minta, Akwasi; Escamilla, P Rogelio; Chan, Patrick P L; Meshik, Xenia A; Goldberg, Mark P


    Although many synthetic calcium indicators are available, a search for compounds with improved characteristics continues. Here, we describe the synthesis and properties of Asante Calcium Red-1 (ACR-1) and its low affinity derivative (ACR-1-LA) created by linking BAPTA to seminaphthofluorescein. The indicators combine a visible light (450-540 nm) excitation with deep-red fluorescence (640 nm). Upon Ca2+ binding, the indicators raise their fluorescence with longer excitation wavelengths producing higher responses. Although the changes occur without any spectral shifts, it is possible to ratio Ca(2+)-dependent (640 nm) and quasi-independent (530 nm) emission when using visible (calcium indicators. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Calcium signal communication in the central nervous system. (United States)

    Braet, Katleen; Cabooter, Liesbet; Paemeleire, Koen; Leybaert, Luc


    The communication of calcium signals between cells is known to be operative between neurons where these signals integrate intimately with electrical and chemical signal communication at synapses. Recently, it has become clear that glial cells also exchange calcium signals between each other in cultures and in brain slices. This communication pathway has received utmost attention since it is known that astrocytic calcium signals can be induced by neuronal stimulation and can be communicated back to the neurons to modulate synaptic transmission. In addition to this, cells that are generally not considered as brain cells become progressively incorporated in the picture, as astrocytic calcium signals are reported to be communicated to endothelial cells of the vessel wall and can affect smooth muscle cell tone to influence the vessel diameter and thus blood flow. We review the available evidence for calcium signal communication in the central nervous system, taking into account a basic functional unit -the brain cell tripartite- consisting of neurons, glial cells and vascular cells and with emphasis on glial-vascular calcium signaling aspects.

  10. Calcium-Responsive Liposomes via a Synthetic Lipid Switch. (United States)

    Lou, Jinchao; Carr, Adam J; Watson, Alexa J; Mattern-Schain, Samuel I; Best, Michael D


    Liposomal drug delivery would benefit from enhanced control over content release. Here, we report a novel avenue for triggering release driven by chemical composition using liposomes sensitized to calcium-a target chosen due to its key roles in biology and disease. To demonstrate this principle, we synthesized calcium-responsive lipid switch 1, designed to undergo conformational changes upon calcium binding. The conformational change perturbs membrane integrity, thereby promoting cargo release. This was shown through fluorescence-based release assays via dose-dependent response depending on the percentage of 1 in liposomes, with minimal background leakage in controls. DLS experiments indicated dramatic changes in particle size upon treatment of liposomes containing 1 with calcium. In a comparison of ten naturally occurring metal cations, calcium provided the greatest release. Finally, STEM images showed significant changes in liposome morphology upon treatment of liposomes containing 1 with calcium. These results showcase lipid switches driven by molecular recognition principles as an exciting avenue for controlling membrane properties. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Effect of calcium carbonate on hardening, physicochemical properties, and in vitro degradation of injectable calcium phosphate cements.

    NARCIS (Netherlands)

    Sariibrahimoglu, K.; Leeuwenburgh, S.C.G.; Wolke, J.G.C.; Yubao, L.; Jansen, J.A.


    The main disadvantage of apatitic calcium phosphate cements (CPCs) is their slow degradation rate, which limits complete bone regeneration. Carbonate (CO(3)(2)(-)) is the common constituent of bone and it can be used to improve the degradability of the apatitic calcium phosphate ceramics. This study

  12. Calcium in the prevention of postmenopausal osteoporosis: EMAS clinical guide. (United States)

    Cano, Antonio; Chedraui, Peter; Goulis, Dimitrios G; Lopes, Patrice; Mishra, Gita; Mueck, Alfred; Senturk, Levent M; Simoncini, Tommaso; Stevenson, John C; Stute, Petra; Tuomikoski, Pauliina; Rees, Margaret; Lambrinoudaki, Irene


    Postmenopausal osteoporosis is a highly prevalent disease. Prevention through lifestyle measures includes an adequate calcium intake. Despite the guidance provided by scientific societies and governmental bodies worldwide, many issues remain unresolved. To provide evidence regarding the impact of calcium intake on the prevention of postmenopausal osteoporosis and critically appraise current guidelines. Literature review and consensus of expert opinion. The recommended daily intake of calcium varies between 700 and 1200mg of elemental calcium, depending on the endorsing source. Although calcium can be derived either from the diet or supplements, the former source is preferred. Intake below the recommended amount may increase fragility fracture risk; however, there is no consistent evidence that calcium supplementation at, or above, recommended levels reduces risk. The addition of vitamin D may minimally reduce fractures, mainly among institutionalised people. Excessive intake of calcium, defined as higher than 2000mg/day, can be potentially harmful. Some studies demonstrated harm even at lower dosages. An increased risk for cardiovascular events, urolithiasis and even fractures has been found in association with excessive calcium intake, but this issue remains unresolved. In conclusion, an adequate intake of calcium is recommended for general bone health. Excessive calcium intake seems of no benefit, and could possibly be harmful. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Calcium spikes and calcium plateaux evoked by differential polarization in dendrites of turtle motoneurones in vitro

    DEFF Research Database (Denmark)

    Hounsgaard, J; Kiehn, O


    The ability of dendrites in turtle motoneurones to support calcium spikes and calcium plateaux was investigated using differential polarization by applied electric fields. 2. Electric fields were generated by passing current through transverse slices of the turtle spinal cord between two plate......+ spikes and Ca2+ plateaux are present in dendrites of spinal motoneurones of the turtle....

  14. Discovery and Development of Calcium Channel Blockers

    Directory of Open Access Journals (Sweden)

    Théophile Godfraind


    Full Text Available In the mid 1960s, experimental work on molecules under screening as coronary dilators allowed the discovery of the mechanism of calcium entry blockade by drugs later named calcium channel blockers. This paper summarizes scientific research on these small molecules interacting directly with L-type voltage-operated calcium channels. It also reports on experimental approaches translated into understanding of their therapeutic actions. The importance of calcium in muscle contraction was discovered by Sidney Ringer who reported this fact in 1883. Interest in the intracellular role of calcium arose 60 years later out of Kamada (Japan and Heibrunn (USA experiments in the early 1940s. Studies on pharmacology of calcium function were initiated in the mid 1960s and their therapeutic applications globally occurred in the the 1980s. The first part of this report deals with basic pharmacology in the cardiovascular system particularly in isolated arteries. In the section entitled from calcium antagonists to calcium channel blockers, it is recalled that drugs of a series of diphenylpiperazines screened in vivo on coronary bed precontracted by angiotensin were initially named calcium antagonists on the basis of their effect in depolarized arteries contracted by calcium. Studies on arteries contracted by catecholamines showed that the vasorelaxation resulted from blockade of calcium entry. Radiochemical and electrophysiological studies performed with dihydropyridines allowed their cellular targets to be identified with L-type voltage-operated calcium channels. The modulated receptor theory helped the understanding of their variation in affinity dependent on arterial cell membrane potential and promoted the terminology calcium channel blocker (CCB of which the various chemical families are introduced in the paper. In the section entitled tissue selectivity of CCBs, it is shown that characteristics of the drug, properties of the tissue, and of the stimuli are

  15. Alterations in calcium metabolism during human monocyte activation

    International Nuclear Information System (INIS)

    Scully, S.P.


    Human peripheral blood monocytes have been prepared from plateletpheresis residues by counterflow centrifugal elutriation in sufficient quantities to enable quantitative studies of cell calcium. Kinetic analysis of 45 Ca exchange data in resting monocytes was compatible with a model of cellular calcium containing three exchangeable calcium pools. These pools are thought to represent a putative ectocellular pool, a putative cytoplasmic chelated pool, and a putative organelle sequestered pool. Exposure of monocytes to the plant lectin Con A at a concentration that maximally simulated superoxide production caused an increase in the size and a doubling in the exchange rate of the putative cytoplasmic pool without a change in the other cellular pools. The cytoplasmic ionized calcium, [Ca]/sub i/, measured with the fluorescent probe, Quin 2 rose from a resting level of 83 nM to 165 mN within 30 sec of exposure to Con A. This increase in cytoplasmic calcium preceded the release of superoxide radicals. Calcium transport and calcium ATPase activities were identified and characterized in plasma membrane vesicles prepared from monocytes. Both activities were strictly dependent on ATP and Mg, had a Km/sub Ca/ in the submicromolar range and were stimulated by calmodulin. Thus, it seems that monocyte calcium is in a dynamic steady state that is a balance between efflux and influx rates, and that the activation of these cells results in the transition to a new steady state. The alteration in [Ca]/sub i/ that accompany the new steady state are essential for superoxide production by human monocytes

  16. Excessive signal transduction of gain-of-function variants of the calcium-sensing receptor (CaSR are associated with increased ER to cytosol calcium gradient.

    Directory of Open Access Journals (Sweden)

    Marianna Ranieri

    Full Text Available In humans, gain-of-function mutations of the calcium-sensing receptor (CASR gene are the cause of autosomal dominant hypocalcemia or type 5 Bartter syndrome characterized by an abnormality of calcium metabolism with low parathyroid hormone levels and excessive renal calcium excretion. Functional characterization of CaSR activating variants has been so far limited at demonstrating an increased sensitivity to external calcium leading to lower Ca-EC50. Here we combine high resolution fluorescence based techniques and provide evidence that for the efficiency of calcium signaling system, cells expressing gain-of-function variants of CaSR monitor cytosolic and ER calcium levels increasing the expression of the Sarco-Endoplasmic Reticulum Calcium-ATPase (SERCA and reducing expression of Plasma Membrane Calcium-ATPase (PMCA. Wild-type CaSR (hCaSR-wt and its gain-of-function (hCaSR-R990G; hCaSR-N124K variants were transiently transfected in HEK-293 cells. Basal intracellular calcium concentration was significantly lower in cells expressing hCaSR-wt and its gain of function variants compared to mock. In line, FRET studies using the D1ER probe, which detects [Ca2+]ER directly, demonstrated significantly higher calcium accumulation in cells expressing the gain of function CaSR variants compared to hCaSR-wt. Consistently, cells expressing activating CaSR variants showed a significant increase in SERCA activity and expression and a reduced PMCA expression. This combined parallel regulation in protein expression increases the ER to cytosol calcium gradient explaining the higher sensitivity of CaSR gain-of-function variants to external calcium. This control principle provides a general explanation of how cells reliably connect (and exacerbate receptor inputs to cell function.

  17. The formation reaction of calcium hexa-aluminate

    International Nuclear Information System (INIS)

    Tuganova, S.Kh.; Sirajiddinov, N.A.


    The formation reaction of CaAl 12 O 19 at interaction of calcium oxide and aluminium in solid form has been studied. Some physical-chemical characteristics of calcium hexa-aluminate are given. (author)

  18. Effects of intravenous administration of two volumes of calcium solution on plasma ionized calcium concentration and recovery from naturally occurring hypocalcemia in lactating dairy cows.

    NARCIS (Netherlands)

    Doze, J.G.; Donders, R.; Kolk, J.H. van der


    OBJECTIVE: To compare the effects of administration of 2 volumes of a calcium solution (calcium oxide and calcium gluconate) on plasma ionized calcium concentration (PICaC) and clinical recovery from naturally occurring hypocalcemia (NOHC; milk fever) in lactating dairy cows. ANIMALS: 123 cows with

  19. Hypoparathyroidism: what is the best calcium carbonate supplementation intake form? (United States)

    Gollino, Loraine; Biagioni, Maria Fernanda Giovanetti; Sabatini, Nathalia Regina; Tagliarini, José Vicente; Corrente, José Eduardo; Paiva, Sérgio Alberto Rupp de; Mazeto, Gláucia Maria Ferreira da Silva


    In hypoparathyroidism, calcium supplementation using calcium carbonate is necessary for the hypocalcemia control. The best calcium carbonate intake form is unknown, be it associated with feeding, juice or in fasting. The objective was to evaluate the calcium, phosphorus and Calcium×Phosphorus product serum levels of hypoparathyroidism women after total thyroidectomy, following calcium carbonate intake in three different forms. A crossover study was carried out with patients presenting definitive hypoparathyroidism, assessed in different situations (fasting, with water, orange juice, breakfast with a one-week washout). Through the review of clinical data records of tertiary hospital patients from 1994 to 2010, 12 adult women (18 50 years old) were identified and diagnosed with definitive post-thyroidectomy hypoparathyroidism. The laboratory results of calcium and phosphorus serum levels dosed before and every 30min were assessed, for 5h, after calcium carbonate intake (elementary calcium 500mg). The maximum peak average values for calcium, phosphorus and Calcium×Phosphorus product were 8.63mg/dL (water), 8.77mg/dL (orange juice) and 8.95mg/dL (breakfast); 4.04mg/dL (water), 4.03mg/dL (orange juice) and 4.12mg/dL (breakfast); 34.3mg 2 /dL 2 (water), 35.8mg 2 /dL 2 (orange juice) and 34.5mg 2 /dL 2 (breakfast), respectively, and the area under the curve 2433mg/dLmin (water), 2577mg/dLmin (orange juice) and 2506mg/dLmin (breakfast), 1203mg/dLmin (water), 1052mg/dLmin (orange juice) and 1128mg/dLmin (breakfast), respectively. There was no significant difference among the three different tests (p>0.05). The calcium, phosphorus and Calcium×Phosphorus product serum levels evolved in a similar fashion in the three calcium carbonate intake forms. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  20. The effect of calcium hydroxide treatment on the nutritive and feeding value of Albizia procera for growing goats

    Energy Technology Data Exchange (ETDEWEB)

    Alam, M.R. [Department of Animal Science, Bangladesh Agricultural University, Mymensingh (Bangladesh)]. E-mail:; Kabir, A.K.M.A.; Amin, M.R. [Department of Animal Science, Bangladesh Agricultural University, Mymensingh (Bangladesh); McNeill, D.M. [Faculty of Veterinary Science, University of Sydney, Camden, NSW (Australia)


    into a 35% improvement in growth rate (40, 36 g/day versus 26, 29 g/day). Calcium hydroxide alone did not improve the feeding value of Albizia. These data highlight the danger of assuming an assayable reduction in tannin, such as that observed in the calcium hydroxide treatment, will translate into an improvement in nutritive value and subsequent animal performance. Since the performance of the goats improved maximally when PEG was added to the calcium hydroxide-treated Albizia it was clear that the tannins were still as active as in the untreated Albizia. It was concluded that calcium hydroxide does not deactivate the tannins in Albizia. (author)

  1. The effect of calcium hydroxide treatment on the nutritive and feeding value of Albizia procera for growing goats

    International Nuclear Information System (INIS)

    Alam, M.R.; Kabir, A.K.M.A.; Amin, M.R.; McNeill, D.M.


    into a 35% improvement in growth rate (40, 36 g/day versus 26, 29 g/day). Calcium hydroxide alone did not improve the feeding value of Albizia. These data highlight the danger of assuming an assayable reduction in tannin, such as that observed in the calcium hydroxide treatment, will translate into an improvement in nutritive value and subsequent animal performance. Since the performance of the goats improved maximally when PEG was added to the calcium hydroxide-treated Albizia it was clear that the tannins were still as active as in the untreated Albizia. It was concluded that calcium hydroxide does not deactivate the tannins in Albizia. (author)

  2. Calcium regulates caveolin-1 expression at the transcriptional level

    International Nuclear Information System (INIS)

    Yang, Xiao-Yan; Huang, Cheng-Cheng; Kan, Qi-Ming; Li, Yan; Liu, Dan; Zhang, Xue-Cheng; Sato, Toshinori; Yamagata, Sadako; Yamagata, Tatsuya


    Highlights: ► Caveolin-1 expression is regulated by calcium signaling at the transcriptional level. ► An inhibitor of or siRNA to L-type calcium channel suppressed caveolin-1 expression. ► Cyclosporine A or an NFAT inhibitor markedly reduced caveolin-1 expression. ► Caveolin-1 regulation by calcium signaling is observed in several mouse cell lines. -- Abstract: Caveolin-1, an indispensable component of caveolae serving as a transformation suppressor protein, is highly expressed in poorly metastatic mouse osteosarcoma FBJ-S1 cells while highly metastatic FBJ-LL cells express low levels of caveolin-1. Calcium concentration is higher in FBJ-S1 cells than in FBJ-LL cells; therefore, we investigated the possibility that calcium signaling positively regulates caveolin-1 in mouse FBJ-S1 cells. When cells were treated with the calcium channel blocker nifedipine, cyclosporin A (a calcineurin inhibitor), or INCA-6 (a nuclear factor of activated T-cells [NFAT] inhibitor), caveolin-1 expression at the mRNA and protein levels decreased. RNA silencing of voltage-dependent L-type calcium channel subunit alpha-1C resulted in suppression of caveolin-1 expression. This novel caveolin-1 regulation pathway was also identified in mouse NIH 3T3 cells and Lewis lung carcinoma cells. These results indicate that caveolin-1 is positively regulated at the transcriptional level through a novel calcium signaling pathway mediated by L-type calcium channel/Ca 2+ /calcineurin/NFAT.

  3. Familial hypocalciuric hypercalcemia and calcium sensing receptor

    DEFF Research Database (Denmark)

    Mrgan, Monija; Nielsen, Sanne; Brixen, Kim


    Familial hypocalciuric hypercalcemia (FHH) is a lifelong, benign autosomal dominant disease characterized by hypercalcemia, normal to increased parathyroid hormone level, and a relatively low renal calcium excretion. Inactivation of the calcium-sensing receptor in heterozygous patients results...... in FHH, while in homozygous patients as well as in compound heterozygous or dominant negative heterozygous patients, it may result in neonatal severe hyperparathyroidism (NSHPT). Parathyroid surgery is not indicated in FHH and does not lower plasma calcium unless total parathyroidectomy is performed...

  4. Calcium as a signal integrator in developing epithelial tissues. (United States)

    Brodskiy, Pavel A; Zartman, Jeremiah J


    Decoding how tissue properties emerge across multiple spatial and temporal scales from the integration of local signals is a grand challenge in quantitative biology. For example, the collective behavior of epithelial cells is critical for shaping developing embryos. Understanding how epithelial cells interpret a diverse range of local signals to coordinate tissue-level processes requires a systems-level understanding of development. Integration of multiple signaling pathways that specify cell signaling information requires second messengers such as calcium ions. Increasingly, specific roles have been uncovered for calcium signaling throughout development. Calcium signaling regulates many processes including division, migration, death, and differentiation. However, the pleiotropic and ubiquitous nature of calcium signaling implies that many additional functions remain to be discovered. Here we review a selection of recent studies to highlight important insights into how multiple signals are transduced by calcium transients in developing epithelial tissues. Quantitative imaging and computational modeling have provided important insights into how calcium signaling integration occurs. Reverse-engineering the conserved features of signal integration mediated by calcium signaling will enable novel approaches in regenerative medicine and synthetic control of morphogenesis.

  5. A novel biphasic calcium phosphate derived from fish otoliths (United States)

    Montañez-Supelano, N. D.; Sandoval-Amador, A.; Estupiñan-Durán, H. A.; Y Peña-Ballesteros, D.


    Calcium phosphates are bioceramics that have been widely used as bone substitutes because they encourage the formation of bone on their surface and can improve the healing of the bone. Hydroxyapatite HA (calcium/phosphorus ratio of 1.67) and tricalcium phosphate TCP (calcium/phosphorus ratio of 1.50) are the most common calcium phosphates. Natural materials have begun to be tested to make HA or TCP such as shells of cardiidae (family of mollusks) and eggshells. The calcium phosphate obtained has a high ability to precipitate apatite. In this work, the mixed phase ceramic of beta-Tri-calcium phosphate / hydroxyapatite (β-TCP/HA) was synthesized by aqueous precipitation from fish otoliths, which are monomineralic species composed of aragonite. Otoliths of the specie Plagioscion squamosissimus, commonly called the river croaker, were used. Techniques such as DRX, Raman spectroscopy and SEM-EDS were used to characterize the raw material and the obtained material. X-ray diffraction analysis revealed the presence of two crystalline phases of calcium phosphates with 86.2% crystallinity. SEM micrographs showed agglomeration of particles with porous structure and submicron particle sizes.

  6. Improved detection of calcium-binding proteins in polyacrylamide gels

    International Nuclear Information System (INIS)

    Anthony, F.A.; Babitch, J.A.


    The authors refined the method of Schibeci and Martonosi (1980) to enhance detection of calcium-binding proteins in polyacrylamide gels using 45 Ca 2+ . Their efforts have produced a method which is shorter, has 40-fold greater sensitivity over the previous method, and will detect 'EF hand'-containing calcium-binding proteins in polyacrylamide gels below the 0.5 μg level. In addition this method will detect at least one example from every described class of calcium-binding protein, including lectins and γ-carboxyglutamic acid containing calcium-binding proteins. The method should be useful for detecting calcium-binding proteins which may trigger neurotransmitter release. (Auth.)

  7. Investigation of cleaning reagents for calcium chromate spills

    International Nuclear Information System (INIS)

    Dillard, B.M.


    Cleaning of calcium chromate spills can be a problem due to the insolubility of the material and the corrosiveness of several possible cleaning agents on the stainless steel equipment. Because of OSHA Standards for Cr(VI) exposure, it is necessary to remove spills as efficiently as possible in order to prevent the contaminant from becoming airborne. This study involved the comparison of several possible cleaning agents by studying the solubility of calcium chromate in each reagent. Two general types of reagents for dissolution of calcium chromate were investigated; those which act by conversion of the insoluble calcium chromate to a more soluble salt and to H 2 CrO 4 , and those which appear to act as complexing agents and thereby dissolve the calcium chromate. The most efficient of the reagents investigated was hydrochloric acid. However, even dilute solutions of halide acids destroy passivity of stainless steel causing pitting and stress-corrosion. Acetic acid and nitric acid were somewhat less efficient than hydrochloric acid in dissolving calcium chromate. However, both reagents are noncorrosive with stainless steel, nitric acid tending to favor passivity of the materials. Therefore, it is recommended that dilute solutions of either of these two acids be used for removal of calcium chromate spills in conjunction with mechanical methods that might be necessary, depending on the magnitude of the spill

  8. Calcium absorption response to cholecalciferol supplementation in hemodialysis. (United States)

    Armas, Laura A G; Zena, Mohsen; Lund, Richard; Heaney, Robert P


    Recent understanding of extrarenal production of calcitriol has led to the use of more vitamin D supplementation in CKD populations. This paper reports the effect of cholecalciferol supplementation on calcium absorption. Paired calcium absorption tests were done before and after 12-13 weeks of 20,000 IU weekly cholecalciferol supplementation in 30 participants with stage 5 CKD on hemodialysis. The study was conducted from April to December of 2011. Calcium absorption was tested with a standardized meal containing 300 mg calcium carbonate intrinsically labeled with (45)Ca; 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were measured. 25-Hydroxyvitamin D rose from 14.2 ng/ml (11.5-18.5) at baseline to 49.3 ng/ml (42.3-58.1) at the end of the study (P<0.001). 1,25-Dihydroxyvitamin D rose from 15.1 (10.5-18.8) pg/ml at baseline to 20.5 (17.0-24.7) pg/ml at the end of the study (P<0.001). The median baseline calcium absorption was 12% (7%-17%) and 12% (7%-16%) at the end of study. Patients with stage 5 CKD on hemodialysis had very low calcium absorption values at baseline, and cholecalciferol supplementation that raised 25(OH)D levels to 50 ng/ml had no effect on calcium absorption.

  9. Role of calcium-enriched mixture in endodontics

    Directory of Open Access Journals (Sweden)

    Pradeep Kabbinale


    Full Text Available Calcium-enriched mixture (CEM has been recently introduced as a hydrophilic tooth-colored cement. The CEM cement powder is composed of calcium oxide, calcium sulfate, phosphorus oxide, and silica as major elements. CEM is alkaline cement (pH~11 that releases calcium hydroxide (CH during and after setting. The physical properties of CEM, such as flow, film thickness, and primary setting time are favorable. This cement is biocompatible and induces formation of cementum, dentin, bone and periodontal tissues. This novel cement has an antibacterial effect comparable to CH and superior to mineral trioxide aggregate (MTA and sealing ability similar to MTA. Its clinical applications include pulp capping, pulpotomy, root-end filling and perforation repair. This review describes the composition, properties and clinical applications of CEM in endodontics.

  10. Short-range intercellular calcium signaling in bone

    DEFF Research Database (Denmark)

    Jørgensen, Niklas R


    The regulation of bone turnover is a complex and finely tuned process. Many factors regulate bone remodeling, including hormones, growth factors, cytokines etc. However, little is known about the signals coupling bone formation to bone resorption, and how mechanical forces are translated...... into biological effects in bone. Intercellular calcium waves are increases in intracellular calcium concentration in single cells, subsequently propagating to adjacent cells, and can be a possible mechanism for the coupling of bone formation to bone resorption. The aim of the present studies was to investigate...... whether bone cells are capable of communicating via intercellular calcium signals, and determine by which mechanisms the cells propagate the signals. First, we found that osteoblastic cells can propagate intercellular calcium transients upon mechanical stimulation, and that there are two principally...

  11. Requirement for nuclear calcium signaling in Drosophila long-term memory. (United States)

    Weislogel, Jan-Marek; Bengtson, C Peter; Müller, Michaela K; Hörtzsch, Jan N; Bujard, Martina; Schuster, Christoph M; Bading, Hilmar


    Calcium is used throughout evolution as an intracellular signal transducer. In the mammalian central nervous system, calcium mediates the dialogue between the synapse and the nucleus that is required for transcription-dependent persistent neuronal adaptations. A role for nuclear calcium signaling in similar processes in the invertebrate brain has yet to be investigated. Here, we show by in vivo calcium imaging of adult brain neurons of the fruit fly Drosophila melanogaster, that electrical foot shocks used in olfactory avoidance conditioning evoked transient increases in cytosolic and nuclear calcium concentrations in neurons. These calcium signals were detected in Kenyon cells of the flies' mushroom bodies, which are sites of learning and memory related to smell. Acute blockade of nuclear calcium signaling during conditioning selectively and reversibly abolished the formation of long-term olfactory avoidance memory, whereas short-term, middle-term, or anesthesia-resistant olfactory memory remained unaffected. Thus, nuclear calcium signaling is required in flies for the progression of memories from labile to transcription-dependent long-lasting forms. These results identify nuclear calcium as an evolutionarily conserved signal needed in both invertebrate and vertebrate brains for transcription-dependent memory consolidation.

  12. ATP-dependent calcium transport across basal plasma membranes of human placental trophoblast

    International Nuclear Information System (INIS)

    Fisher, G.J.; Kelley, L.K.; Smith, C.H.


    As a first step in understanding the cellular basis of maternal-fetal calcium transfer, the authors examined the characteristics of calcium uptake by a highly purified preparation of the syncytiotrophoblast basal (fetal facing) plasma membrane. In the presence of nanomolar concentrations of free calcium, basal membranes demonstrated substantial ATP-dependent calcium uptake. This uptake required magnesium, was not significantly affected by Na + or K + (50 mM), or sodium azide (10 mM). Intravesicular calcium was rapidly and completely released by the calcium ionophore rapidly and completely released by the calcium ionophore A23187. Calcium transport was significantly stimulated by the calcium-dependent regulatory protein calmodulin. Placental membrane fractions enriched in endoplasmic reticulum (ER) and mitochondria also demonstrated ATP-dependent calcium uptake. In contrast to basal membrane, mitochondrial calcium uptake was completely inhibited by azide. The rate of calcium uptake was completely inhibited by azide. The rate of calcium uptake by the ER was only 20% of that of basal membranes. They conclude that the placental basal plasma membrane possesses a high-affinity calcium transport system similar to that found in plasma membranes of a variety of cell types. This transporter is situated to permit it to function in vivo in maternal-fetal calcium transfer

  13. Young Adults' Perceptions of Calcium Intake and Health: A Qualitative Study. (United States)

    Marcinow, Michelle L; Randall Simpson, Janis A; Whiting, Susan J; Jung, Mary E; Buchholz, Andrea C


    Many young Canadian adults are not meeting dietary calcium recommendations. This is concerning as adequate calcium is important throughout young adulthood to maximize peak bone mass for osteoporosis prevention. There are limited studies that have explored young adults' perceptions toward calcium and health. Our objectives were to determine young adults' (18-34 years) knowledge of calcium in relation to health, facilitators and barriers to adequate calcium intake, and to explore both their suggestions for individual strategies to increase calcium intake and ways to communicate calcium-related messaging to this population. Eight gender-specific focus groups (18 men; 35 women) were conducted using a semistructured interview guide, guided by social cognitive theory. Deductive thematic analysis was used to generate themes. Participants perceived adequate calcium intake to be important for children and older adults but were uncertain of the benefits for their own age group. Perceived positive outcomes (e.g., aesthetics such as strong nails) associated with adequate calcium intake were cited as a motivator to increase intake. Perceived barriers to achieving increased calcium intake included the high cost and inconvenience of milk products and negative practices of dairy farmers. Participants suggested planning healthy well-balanced meals and forming a habit of consuming calcium-rich foods as individual strategies to increase calcium intake. Strategies to convey calcium-related information to young adults included increasing awareness of the importance of calcium via credible sources of information and developing nutrition education curricula. Social media and advertising were perceived as ineffective. Our findings provide key information for nutrition education initiatives.

  14. 21 CFR 184.1187 - Calcium alginate. (United States)


    ... ingredient is used in food only within the following specific limitations: Category of food Maximum level of... other food categories 0.3 Do. (d) Prior sanctions for calcium alginate different from the uses... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium alginate. 184.1187 Section 184.1187 Food...

  15. Characterization of branchial transepithelial calcium fluxes in freshwater trout, Salmo gairdneri

    International Nuclear Information System (INIS)

    Perry, S.F.; Flik, G.


    Experiments were performed to determine whether gill transepithelial calcium fluxes in the freshwater trout (Salmo gairdneri) are passive or require active transport and to characterize the mechanism involved. A comparison of the in vivo unidirectional flux ratios with the flux ratios calculated according to the transepithelial electrochemical gradients revealed that calcium uptake from the water requires active transport of Ca 2+ . The inhibition of calcium uptake by external lanthanum, the specific deposition of lanthanum on the apical surface of chloride cells, and the favorable electrochemical gradient for calcium across the apical membrane suggest that the initial step in branchial calcium uptake is the passive entry of calcium into the cytosol of chloride cells through apical channels that are permeable to calcium. The study of gill basolateral plasma membrane vesicles demonstrated the existence of a high-affinity calmodulin-dependent calcium-transporting system. This system actively transports calcium from the cytosol of chloride cells into the plasma against a sizeable electrochemical gradient, thereby completing the transepithelial uptake of calcium. Calcium efflux occurs passively through paracellular pathways between chloride cells and adjacent pavement cells or between neighboring pavement cells

  16. Zinc oxide nanoparticles decrease the expression and activity of plasma membrane calcium ATPase, disrupt the intracellular calcium homeostasis in rat retinal ganglion cells. (United States)

    Guo, Dadong; Bi, Hongsheng; Wang, Daoguang; Wu, Qiuxin


    Zinc oxide nanoparticle is one of the most important materials with diverse applications. However, it has been reported that zinc oxide nanoparticles are toxic to organisms, and that oxidative stress is often hypothesized to be an important factor in cytotoxicity mediated by zinc oxide nanoparticles. Nevertheless, the mechanism of toxicity of zinc oxide nanoparticles has not been completely understood. In this study, we investigated the cytotoxic effect of zinc oxide nanoparticles and the possible molecular mechanism involved in calcium homeostasis mediated by plasma membrane calcium ATPase in rat retinal ganglion cells. Real-time cell electronic sensing assay showed that zinc oxide nanoparticles could exert cytotoxic effect on rat retinal ganglion cells in a concentration-dependent manner; flow cytometric analysis indicated that zinc oxide nanoparticles could lead to cell damage by inducing the overproduction of reactive oxygen species. Furthermore, zinc oxide nanoparticles could also apparently decrease the expression level and their activity of plasma membrane calcium ATPase, which finally disrupt the intracellular calcium homeostasis and result in cell death. Taken together, zinc oxide nanoparticles could apparently decrease the plasma membrane calcium ATPase expression, inhibit their activity, cause the elevated intracellular calcium ion level and disrupt the intracellular calcium homeostasis. Further, the disrupted calcium homeostasis will trigger mitochondrial dysfunction, generate excessive reactive oxygen species, and finally initiate cell death. Thus, the disrupted calcium homeostasis is involved in the zinc oxide nanoparticle-induced rat retinal ganglion cell death. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Functional characterization of calcium sensing receptor polymorphisms and absence of association with indices of calcium homeostasis and bone mineral density. (United States)

    Harding, Brian; Curley, Alan J; Hannan, Fadil M; Christie, Paul T; Bowl, Michael R; Turner, Jeremy J O; Barber, Mathew; Gillham-Nasenya, Irina; Hampson, Geeta; Spector, Tim D; Thakker, Rajesh V


    Associations between calcium-sensing receptor (CaSR) polymorphisms and serum calcium, PTH and bone mineral density (BMD) have been reported by six studies. However, three other studies have failed to detect such associations. We therefore further investigated three CaSR coding region polymorphisms (Ala986Ser, Arg990Gly and Gln1011Glu) for associations with indices of calcium homeostasis and BMD and for alterations in receptor function. One hundred and ten adult, Caucasian, female, dizygotic twin pairs were investigated for associations between the three CaSR polymorphisms and serum calcium, albumin, PTH, 25-hydroxyvitamin D(3) (25OHD(3)), 1,25-dihydroxyvitamin D(3)[1,25(OH)(2)D(3)], urinary calcium excretion and BMD. Each polymorphic CaSR was also transfected into HEK293 cells and functionally evaluated. There was a lack of association between each of these three CaSR polymorphisms and serum calcium corrected for albumin, PTH, 25OHD(3), 1,25(OH)(2)D(3), urinary calcium excretion or BMD at the hip, forearm and lumbar spine. These findings were supported by a lack of functional differences in the dose-response curves of the CaSR variants, with the EC(50) values (mean +/- SEM) of the wild-type (Ala986/Arg990/Gln1011), Ser986, Gly990 and Glu1011 CaSR variants being 2.74 +/- 0.29 mm, 3.09 +/- 0.34 mm (P > 0.4), 2.99 +/- 0.23 mm (P > 0.4) and 2.96 +/- 0.30 mm (P > 0.5), respectively. Our study, which was sufficiently powered to detect effects that would explain up to 5%, but not less than 1%, of the variance has revealed that the three CaSR polymorphisms of the coding region have no major influence on indices of calcium homeostasis in this female population, and that they do not alter receptor function.

  18. Calcium-regulated in vivo protein phosphorylation in Zea mays L. root tips (United States)

    Raghothama, K. G.; Reddy, A. S.; Friedmann, M.; Poovaiah, B. W.


    Calcium dependent protein phosphorylation was studied in corn (Zea mays L.) root tips. Prior to in vivo protein phosphorylation experiments, the effect of calcium, ethyleneglycol-bis-(beta-aminoethyl ether)-N-N' -tetraacetic acid (EGTA) and calcium ionophore (A-23187) on phosphorus uptake was studied. Calcium increased phosphorus uptake, whereas EGTA and A-23187 decreased it. Consequently, phosphorus concentration in the media was adjusted so as to attain similar uptake in different treatments. Phosphoproteins were analyzed by two-dimensional gel electrophoresis. Distinct changes in phosphorylation were observed following altered calcium levels. Calcium depletion in root tips with EGTA and A-23187 decreased protein phosphorylation. However, replenishment of calcium following EGTA and ionophore pretreatment enhanced phosphorylation of proteins. Preloading of the root tips with 32P in the presence of EGTA and A-23187 followed by a ten minute calcium treatment, resulted in increased phosphorylation indicating the involvement of calcium, calcium and calmodulin-dependent kinases. Calmodulin antagonist W-7 was effective in inhibiting calcium-promoted phosphorylation. These studies suggest a physiological role for calcium-dependent phosphorylation in calcium-mediated processes in plants.

  19. Thermodynamics of calcium-isotope-exchange reactions. 1. Exchange between isotopic calcium carbonates and aqueous calcium ions

    International Nuclear Information System (INIS)

    Zhang, R.S.; Nash, C.P.; Rock, P.A.


    This paper reports the authors results for the direct experimental determination of the equilibrium constant for the calcium-isotope-exchange reaction 40 CaCO 3 (s) + 44 CaCl 2 (aq) reversible 44 CaCO 2 (s) + 40 CaCl 2 (aq). The reaction was studied in electrochemical double cells without liquid junction of the type shown in eq 2. The experimental value of the equilibrium constant at 295 +/- 2 K is K = 1.08 +/- 0.02. The experimental value for K is compared with the values of K calculated for various model reactions according to the statistical thermodynamic theory of isotope effects. The isotopic solid carbonates were modeled according to both the Debye and Kieffer theories. No structured models of solvated isotopic aqueous calcium ions yield calculated equilibrium constants in agreement with their experimental results. This conclusion is in agreement with published molecular dynamics calculations which show that the aqueous solvation of Ca 2 =(aq) is essentially unstructured

  20. Development of a degradable cement of calcium phosphate and calcium sulfate composite for bone reconstruction

    International Nuclear Information System (INIS)

    Guo, H; Wei, J; Liu, C S


    A new type of composite bone cement was prepared and investigated by adding calcium sulfate (CS) to calcium phosphate cement (CPC). This composite cement can be handled as a paste and easily shaped into any contour, which can set within 5-20 min, the setting time largely depending on the liquid-solid (L/S) ratio; adding CS to CPC had little effect on the setting time of the composite cements. No obvious temperature increase and pH change were observed during setting and immersion in simulated body fluid (SBF). The compressive strength of the cement decreased with an increase in the content of CS. The degradation rate of the composite cements increased with time when the CS content was more than 20 wt%. Calcium deficient apatite could form on the surface of the composite cement because the release of calcium into SBF from the dissolution of CS and the apatite of the cement induced the new apatite formation; increasing the content of CS in the composite could improve the bioactivity of the composite cements. The results suggested that composite cement has a reasonable setting time, excellent degradability and suitable mechanical strength and bioactivity, which shows promising prospects for development as a clinical cement

  1. Complex formation ions calcium with macromolecules pectin

    International Nuclear Information System (INIS)

    Khalikova, M.D.; Avloev, Kh.Kh.; Muhiddinov, Z.K.


    In clause the mechanism of sorption of ions of calcium by macromolecules of pectin is opened. Is shown, that the linkage of ions of calcium descends on acid bunches of pectin, and process carries cooperative character

  2. Ryanodine receptor gating controls generation of diastolic calcium waves in cardiac myocytes (United States)

    Petrovič, Pavol; Valent, Ivan; Cocherová, Elena; Pavelková, Jana


    The role of cardiac ryanodine receptor (RyR) gating in the initiation and propagation of calcium waves was investigated using a mathematical model comprising a stochastic description of RyR gating and a deterministic description of calcium diffusion and sequestration. We used a one-dimensional array of equidistantly spaced RyR clusters, representing the confocal scanning line, to simulate the formation of calcium sparks. Our model provided an excellent description of the calcium dependence of the frequency of diastolic calcium sparks and of the increased tendency for the production of calcium waves after a decrease in cytosolic calcium buffering. We developed a hypothesis relating changes in the propensity to form calcium waves to changes of RyR gating and tested it by simulation. With a realistic RyR gating model, increased ability of RyR to be activated by Ca2+ strongly increased the propensity for generation of calcium waves at low (0.05–0.1-µM) calcium concentrations but only slightly at high (0.2–0.4-µM) calcium concentrations. Changes in RyR gating altered calcium wave formation by changing the calcium sensitivity of spontaneous calcium spark activation and/or the average number of open RyRs in spontaneous calcium sparks. Gating changes that did not affect RyR activation by Ca2+ had only a weak effect on the propensity to form calcium waves, even if they strongly increased calcium spark frequency. Calcium waves induced by modulating the properties of the RyR activation site could be suppressed by inhibiting the spontaneous opening of the RyR. These data can explain the increased tendency for production of calcium waves under conditions when RyR gating is altered in cardiac diseases. PMID:26009544

  3. Effects of calcium antagonists on isolated bovine cerebral arteries: inhibition of constriction and calcium-45 uptake induced by potassium or serotonin

    International Nuclear Information System (INIS)

    Wendling, W.W.; Harakal, C.


    The purpose of this study was to determine the mechanisms by which organic calcium channel blockers inhibit cerebral vasoconstriction. Isolated bovine middle cerebral arteries were cut into rings to measure contractility or into strips to measure radioactive calcium ( 45 Ca) influx and efflux. Calcium channel blockers (10(-5) M verapamil or 3.3 X 10(-7) M nifedipine) and calcium-deficient solutions all produced near-maximal inhibition of both potassium- and serotonin-induced constriction. In calcium-deficient solutions containing potassium or serotonin, verapamil and nifedipine each blocked subsequent calcium-induced constriction in a competitive manner. Potassium and serotonin significantly increased 45 Ca uptake into cerebral artery strips during 5 minutes of 45 Ca loading; for potassium 45 Ca uptake increased from 62 to 188 nmol/g, and for serotonin from 65 to 102 nmol/g. Verapamil or nifedipine had no effect on basal 45 Ca uptake but significantly blocked the increase in 45 Ca uptake induced by potassium or serotonin. Potassium, and to a lesser extent serotonin, each induced a brief increase in the rate of 45 Ca efflux into calcium-deficient solutions. Verapamil or nifedipine had no effect on basal or potassium-stimulated 45 Ca efflux. The results demonstrate that verapamil and nifedipine block 45 Ca uptake through both potential-operated (potassium) and receptor-operated (serotonin) channels in bovine middle cerebral arteries

  4. Activation of a cGMP-sensitive calcium-dependent chloride channel may cause transition from calcium waves to whole-cell oscillations in smooth muscle cells

    DEFF Research Database (Denmark)

    Jacobsen, Jens Christian; Aalkjær, Christian; Nilsson, Holger


    waves sweeping through the cytoplasm when the SR is stimulated to release calcium. A rise in cyclic guanosine monophosphate (cGMP) leads to the experimentally observed transition from waves to whole-cell calcium oscillations. At the same time membrane potential starts to oscillate and the frequency...... approximately doubles. In this transition, the simulated results point to a key role for a recently discovered cGMP-sensitive calcium-dependent chloride channel. This channel depolarizes the membrane in response to calcium released from the SR. In turn, depolarization causes uniform opening of L-type calcium...... onset of oscillations in membrane potential within the individual cell may underlie sudden intercellular synchronization and the appearance of vasomotion. Key words: Vasomotion, Chloride channel, cGMP, Mathematical model, Calcium waves....

  5. Serum calcium and incident diabetes: an observational study and meta-analysis. (United States)

    Sing, C W; Cheng, V K F; Ho, D K C; Kung, A W C; Cheung, B M Y; Wong, I C K; Tan, K C B; Salas-Salvadó, J; Becerra-Tomas, N; Cheung, C L


    The study aimed to prospectively evaluate if serum calcium is related to diabetes incidence in Hong Kong Chinese. The results showed that serum calcium has a significant association with increased risk of diabetes. The result of meta-analysis reinforced our findings. This study aimed to evaluate the association of serum calcium, including serum total calcium and albumin-corrected calcium, with incident diabetes in Hong Kong Chinese. We conducted a retrospective cohort study in 6096 participants aged 20 or above and free of diabetes at baseline. Serum calcium was measured at baseline. Incident diabetes was determined from several electronic databases. We also searched relevant databases for studies on serum calcium and incident diabetes and conducted a meta-analysis using fixed-effect modeling. During 59,130.9 person-years of follow-up, 631 participants developed diabetes. Serum total calcium and albumin-corrected calcium were associated with incident diabetes in the unadjusted model. After adjusting for demographic and clinical variables, the association remained significant only for serum total calcium (hazard ratio (HR), 1.32 (95 % confidence interval (CI), 1.02-1.70), highest vs. lowest quartile). In a meta-analysis of four studies including the current study, both serum total calcium (pooled risk ratio (RR), 1.38 (95 % CI, 1.15-1.65); I (2) = 5 %, comparing extreme quantiles) and albumin-corrected calcium (pooled RR, 1.29 (95 % CI, 1.03-1.61); I (2) = 0 %, comparing extreme quantiles) were associated with incident diabetes. Penalized regression splines showed that the association of incident diabetes with serum total calcium and albumin-correlated calcium was non-linear and linear, respectively. Elevated serum calcium concentration is associated with incident diabetes. The mechanism underlying this association warrants further investigation.

  6. Factors to consider in the selection of a calcium supplement.


    Shangraw, R F


    Calcium supplements are widely used, yet many questions remain as to the absorption of various calcium salts. Because the solubility of many calcium salts is dependent upon pH, the type of salt used, the condition of the patient, and the time of administration should be considered. Studies show that many calcium supplements on the market today do not meet standards of quality established in the "U.S. Pharmacopeia" (USP). Consumers must be discerning about the products they purchase. Calcium s...

  7. Global dietary calcium intake among adults: a systematic review (United States)

    Purpose: Low calcium intake may adversely affect bone health in adults. Recognizing the presence of low calcium intake is necessary to develop national strategies to optimize intake. To highlight regions where calcium intake should be improved, we systematically searched for the most representative ...


    Institute of Scientific and Technical Information of China (English)

    于建; 夏延致


    Calcium alginate fibers were prepared by wet spinning of sodium alginate into a coagulating bath containing calcium chloride.The thermal degradation and flame retardancy of calcium alginate fibers were investigated with thermal gravimetry(TG),X-ray diffraction(XRD),limiting oxygen index(LOI) and cone calorimeter(CONE).The results show that calcium alginate fibers are inherently flame retardant with a LOI value of 34,and the heat release rate(HRR),total heat release(THR),CO and CO_2 concentrations during ...

  9. Mean field strategies induce unrealistic nonlinearities in calcium puffs

    Directory of Open Access Journals (Sweden)

    Guillermo eSolovey


    Full Text Available Mean field models are often useful approximations to biological systems, but sometimes, they can yield misleading results. In this work, we compare mean field approaches with stochastic models of intracellular calcium release. In particular, we concentrate on calcium signals generated by the concerted opening of several clustered channels (calcium puffs. To this end we simulate calcium puffs numerically and then try to reproduce features of the resulting calcium distribution using mean field models were all the channels open and close simultaneously. We show that an unrealistic nonlinear relationship between the current and the number of open channels is needed to reproduce the simulated puffs. Furthermore, a single channel current which is five times smaller than the one of the stochastic simulations is also needed. Our study sheds light on the importance of the stochastic kinetics of the calcium release channel activity to estimate the release fluxes.

  10. Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review (United States)

    Shalavi, S; Yazdizadeh, M


    The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. Calcium hydroxide has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also a valuable anti-endotoxin agent. However, its effect on microbial biofilms is controversial. PMID:23323217

  11. Validation of a Food Frequency Questionnaire for Assessing Macronutrient and Calcium Intake in Adult Pakistani Population

    International Nuclear Information System (INIS)

    Iqbal, R.; Bano, G.; Dar, F. J.; Khan, A. H.; Bilgirami, M.


    Objective: To develop and validate a food frequency table (FFQ) for use in urban Pakistani population. Study Design: A validation study. Place and Duration of Study: The Aga Khan University, Karachi, from June to November 2008. Methodology: Healthy adult females, aged A 18 years who consented to be included in the study were inducted, while males, unhealthy females, aged below 18 years or who did not consent were excluded. The FFQ was administered once while 4, 24 hours recalls spread over a period of one year were administered as the reference method. Daily intakes for energy, protein, fat, and calcium intake were estimated for both the tools. Crude and energy adjusted correlations for nutrient intakes were computed for the FFQ and mean of 4, 24 hours recalls and serum N-telopeptide of type-I collagen (NTx). Results: The correlation coefficients for the FFQ with mean of 4, 24 hours recall ranged from 0.21 for protein to 0.36 for calcium, while the correlation for nutrient estimates from the FFQ with NTx ranged from -0.07 for calcium to 0.01 for energy. Conclusion: Highly significant correlations were found for nutrient intakes estimated from the FFQ vs. those estimated from the mean of 4, 24 hours recalls but no correlations was found between nutrient estimates from the FFQ and serum NTx levels. FFQ was concluded to be a valid tool for assessing dietary intake of adult females in Pakistan. (author)

  12. Calcium status in premenopausal and post menopausal women

    International Nuclear Information System (INIS)

    Qureshi, H.J.; Hussain, G.; Bashir, M.U.; Latif, N.; Riaz, Z.


    Background: In postmenopausal women, the two major causes of bone loss are oestrogen deficiency after menopause and age related processes. Bone turnover increases to high levels and oestrogen deficiency may induce calcium loss by indirect effects on extra skeletal calcium homeostasis. Objective of this study was to evaluate calcium status in pre-menopausal and postmenopausal women. Methods: This cross sectional study was carried out in 34 premenopausal women and 33 postmenopausal women, in Department of Physiology, Services Institute of Medical Sciences, Lahore. Height and weight of each woman were taken to find out the body mass index (BMI). Serum calcium, parathyroid hormone and calcitonin levels of each subject were determined. Results: Premenopausal women were obese (BMI>30 Kg/m/sup 2/) while postmenopausal women were overweight (BMI>25 Kg/m/sup 2/). Serum calcium levels were significantly lower in postmenopausal women than in pre-menopausal women, while serum parathyroid hormone levels were significantly higher in postmenopausal woman. Serum calcitonin level was not significantly different in the two groups. Conclusion: Postmenopausal women are calcium deficient and have increased bone turnover as indicated by increased serum parathyroid hormone levels. (author)

  13. Pharmacological analysis of calcium antagonist receptors

    International Nuclear Information System (INIS)

    Reynolds, I.J.


    This work focuses on two aspects of the action of calcium antagonist drugs, namely, the interaction of drugs with receptors for verapamil-like calcium antagonists, and the interactions of drugs with voltage-sensitive calcium fluxes in rat brain synaptosomes. From binding studies I have found that the ligand of choice for labeling the verapamil receptor is (-)[ 3 H]desmethoxy-verapamil. This drug labels potently, reversibly and stereoselectively two receptors in membranes prepared from rat brain and rabbit skeletal muscle tissues. In equilibrium studies dihydropyridine calcium antagonists interact in a non-competitive fashion, while many non-DHPs are apparently competitive. In-depth kinetic studies in skeletal muscle membranes indicate that the two receptors are linked in a negative heterotropic fashion, and that low-affinity binding of (-) [ 3 H]desmethoxy-verapamil may be to the diltiazem receptor. However, these studies were not able to distinguish between the hypothesis that diltiazem binds to spatially separate, allosterically coupled receptors, and the hypothesis that diltiazem binds to a subsite of the verapamil receptor

  14. Sorption of sulphur dioxide in calcium chloride and nitrate chloride liquids

    International Nuclear Information System (INIS)

    Trzepierczynska, I.; Gostomczyk, M.A.


    Flue gas desulphurization via application of suspensions has one inherent disadvantage: fixation of sulphur dioxide is very poor. This should be attributed to the low content of calcium ions which results from the solubility of the sorbing species. The solubility of sparingly soluble salts (CaO, CaCO 3 ) may be increased by decreasing the pH of the solution; yet, there is a serious limitation in this method: the corrosivity of the scrubber. The objective of this paper was to assess the sorbing capacity of two soluble calcium salts, calcium chloride and calcium nitrate, as a function of calcium ion concentration in the range of 20 to 82 kg/m 3 . It has been found that sorbing capacity increases with the increasing calcium ion concentration until the calcium concentration in the calcium chloride solution reaches the level of 60 kg/m 3 which is equivalent to the chloride ion content of ∼ 110 kg/m 3 . Addition of calcium hydroxide to the solutions brings about an increase in the sorbing capacity up to 1.6 kg/m 3 and 2.2 kg/m 3 for calcium chloride and calcium nitrate, respectively, as a result of the increased sorbent alkalinity. The sorption capacity of the solutions is considerably enhanced by supplementing them by acetate ions (2.8 to 13.9 kg/m 3 ). Increase in the sorption capacity of calcium nitrate solutions enriched with calcium acetate was approximately 30% as high as that of the chloride solutions enriched with calcium acetate was approximately 30% as high as that of the chloride solutions supplemented in the same way. (author). 12 refs, 7 refs, 4 tabs

  15. Calcium Biofortification: Three Pronged Molecular Approaches for Dissecting Complex Trait of Calcium Nutrition in Finger Millet (Eleusine coracana) for Devising Strategies of Enrichment of Food Crops. (United States)

    Sharma, Divya; Jamra, Gautam; Singh, Uma M; Sood, Salej; Kumar, Anil


    Calcium is an essential macronutrient for plants and animals and plays an indispensable role in structure and signaling. Low dietary intake of calcium in humans has been epidemiologically linked to various diseases which can have serious health consequences over time. Major staple food-grains are poor source of calcium, however, finger millet [ Eleusine coracana (L.) Gaertn.], an orphan crop has an immense potential as a nutritional security crop due to its exceptionally high calcium content. Understanding the existing genetic variation as well as molecular mechanisms underlying the uptake, transport, accumulation of calcium ions (Ca 2+ ) in grains is of utmost importance for development of calcium bio-fortified crops. In this review, we have discussed molecular mechanisms involved in calcium accumulation and transport thoroughly, emphasized the role of molecular breeding, functional genomics and transgenic approaches to understand the intricate mechanism of calcium nutrition in finger millet. The objective is to provide a comprehensive up to date account of molecular mechanisms regulating calcium nutrition and highlight the significance of bio-fortification through identification of potential candidate genes and regulatory elements from finger millet to alleviate calcium malnutrition. Hence, finger millet could be used as a model system for explaining the mechanism of elevated calcium (Ca 2+ ) accumulation in its grains and could pave way for development of nutraceuticals or designer crops.

  16. The complex nature of calcium cation interactions with phospholipid bilayers (United States)

    Melcrová, Adéla; Pokorna, Sarka; Pullanchery, Saranya; Kohagen, Miriam; Jurkiewicz, Piotr; Hof, Martin; Jungwirth, Pavel; Cremer, Paul S.; Cwiklik, Lukasz


    Understanding interactions of calcium with lipid membranes at the molecular level is of great importance in light of their involvement in calcium signaling, association of proteins with cellular membranes, and membrane fusion. We quantify these interactions in detail by employing a combination of spectroscopic methods with atomistic molecular dynamics simulations. Namely, time-resolved fluorescent spectroscopy of lipid vesicles and vibrational sum frequency spectroscopy of lipid monolayers are used to characterize local binding sites of calcium in zwitterionic and anionic model lipid assemblies, while dynamic light scattering and zeta potential measurements are employed for macroscopic characterization of lipid vesicles in calcium-containing environments. To gain additional atomic-level information, the experiments are complemented by molecular simulations that utilize an accurate force field for calcium ions with scaled charges effectively accounting for electronic polarization effects. We demonstrate that lipid membranes have substantial calcium-binding capacity, with several types of binding sites present. Significantly, the binding mode depends on calcium concentration with important implications for calcium buffering, synaptic plasticity, and protein-membrane association. PMID:27905555

  17. 40 CFR 721.10011 - Barium calcium manganese strontium oxide. (United States)


    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium calcium...

  18. Preparation and biological efficacy of haddock bone calcium tablets (United States)

    Huo, Jiancong; Deng, Shanggui; Xie, Chao; Tong, Guozhong


    To investigate the possible use of waste products obtained after processing haddock, the present study prepared haddock bone calcium powder by NaOH and ethanol soaking (alkalinealcohol method) and prepared haddock bone calcium tablets using the powder in combination with appropriate excipients. The biological efficacy of the haddock bone calcium tablets was investigated using Wistar rats as an experiment model. Results show that the optimal parameters for the alkalinealcohol method are: NaOH concentration 1 mol/L, immersion time 30 h; ethanol concentration 60%, immersion time 15 h. A mixture of 2% polyvinylpyrrolidone in ethanol was used as an excipient at a ratio of 1:2 to full-cream milk powder, without the use of a disintegrating agent. This process provided satisfactory tablets in terms of rigidity and taste. Animal studies showed that the haddock bone calcium tablets at a dose of 2 g·kg-1·d-1 or 5g·kg-1·d-1 significantly increased blood calcium and phosphorus levels and bone calcium content in rats. Therefore, these tablets could be used for calcium supplementation and prevent osteoporosis. Although the reasons of high absorption in the rats fed with haddock bone calcium tablets are unclear, it is suggested that there are some factors, such as treatment with method of alkaline-alcohol or the added milk, may play positive roles in increasing absorption ratio.

  19. Calcium and bone health in children: a review. (United States)

    Stallings, V A


    The recent national survey shows that dietary calcium intake is variable in children and adolescents, with about half consuming less than the intake recommended by the Recommended Dietary Allowances or the National Institutes of Health Consensus Panel on Optimal Calcium Intake. Osteoporosis is a major disease in adults, resulting in 1.5 million fractures and over $10 billion in medical expenditures annually. Osteoporosis is of growing interest in the research, public health, and health consumer-lay communities and to the many primary care and specialty physicians and other health care professionals who work directly with patients with osteoporosis. Treatment of osteoporosis to prevent fracture is improving with newly introduced medications and approaches, but it is not as effective as needed. Effective prevention strategies are critical to decreasing the morbidity and mortality of the disease. Peak bone mass, obtained during childhood and adolescent growth, is one of the major determinants for the risk of developing osteoporosis and fracture. Genetic potential, gender, ethnic origins, nutritional factors such as calcium and vitamin D intake, growth patterns, and physical activity influence the accretion of bone mineral during childhood and determine the peak bone mass. Randomized, placebo-controlled intervention trials conducted in healthy children who are consuming amounts of dietary calcium in accordance with the US recommendations show that bone mass can be increased by calcium supplementation. Retrospective studies in adults suggest that childhood calcium intake is associated with risk of later osteoporosis and fracture. In addition, common childhood clinical conditions, such as low calcium intake related to lactose intolerance or the use of glucocorticoid medications for chronic illness, are risk factors for the development of osteoporosis in childhood, not just in adulthood. An approach for physicians and other pediatric care providers for screening children

  20. A membrane model for cytosolic calcium oscillations. A study using Xenopus oocytes.


    Jafri, M S; Vajda, S; Pasik, P; Gillo, B


    Cytosolic calcium oscillations occur in a wide variety of cells and are involved in different cellular functions. We describe these calcium oscillations by a mathematical model based on the putative electrophysiological properties of the endoplasmic reticulum (ER) membrane. The salient features of our membrane model are calcium-dependent calcium channels and calcium pumps in the ER membrane, constant entry of calcium into the cytosol, calcium dependent removal from the cytosol, and buffering ...

  1. Preparation of calcium phosphate paste

    International Nuclear Information System (INIS)

    Mohd Reusmaazran Yusof; Norzita Yaacob; Idris Besar; Che Seman Mahmood; Rusnah Mustafa


    Calcium phosphate paste were prepared by mixing between calcium sodium potassium phosphate, Ca 2 NaK (PO 4 ) 2 (CSPP) and monocalcium phosphate monohydrate, Ca(H 2 PO 4 ) 2 .H 2 O (MCPM). CSPP were obtained by reaction between calcium hydrogen phosphate (CaHPO 4 ), potassium carbonate (K 2 CO 3 ) and sodium carbonate (Na 2 CO 3 ) in solid state sintering process followed by quenching in air at 1000 degree Celsius. The paste was aging in simulated body fluid (SBF) for 0.5, 1, 3, 6, 12, 24, 48 hrs, 3, 7 and 14 days. The morphological investigation indicated the formation of apatite crystal were first growth after 24 hours. The obvious growth of apatite crystal was shown at 3 days. The obvious growth of apatite crystal was shown in 7 and 14 days indicated the prediction of paste would have rapid reaction with bone after implantation. (author)

  2. Risk of High Dietary Calcium for Arterial Calcification in Older Adults

    Directory of Open Access Journals (Sweden)

    Philip J. Klemmer


    Full Text Available Concern has recently arisen about the potential adverse effects of excessive calcium intakes, i.e., calcium loading from supplements, on arterial calcification and risks of cardiovascular diseases (CVD in older adults. Published reports that high calcium intakes in free-living adults have relatively little or no beneficial impact on bone mineral density (BMD and fracture rates suggest that current recommendations of calcium for adults may be set too high. Because even healthy kidneys have limited capability of eliminating excessive calcium in the diet, the likelihood of soft-tissue calcification may increase in older adults who take calcium supplements, particularly in those with age or disease-related reduction in renal function. The maintenance of BMD and bone health continues to be an important goal of adequate dietary calcium consumption, but eliminating potential risks of CVDs from excessive calcium intakes needs to be factored into policy recommendations for calcium by adults.

  3. Investigation into process of solid-phase synthesis of calcium vanadates

    International Nuclear Information System (INIS)

    Fotiev, A.A.; Krasnenko, T.I.; Slobodin, B.V.


    Processes of solid-phase synthesis of calcium vanadates by Toubandt method, measuring electric conductivity and Ca 45 and V 48 radioactive indicators are investigated. It is shown that reaction diffusion during calcium vanadates production from oxides is ensured by calcium and oxygen ions or calcium ions and electrons through the product layer, as to oxygen - through the gas phase

  4. The effect of calcium and magnesium supplementation on performance and bone strength of broiler chickens

    Directory of Open Access Journals (Sweden)

    Filip Karásek


    Full Text Available Aim of the experiment was evaluation of the effect of reduced calcium and magnesium content in the broiler chickens diet on its parameters of fattening, bone strength and calcium and magnesium content in liver. The trial was performed with cockerels of Ross 308 hybrid (n = 160 which were fattened in cage batteries from day 11th to 36th day of age. Cockerels were divided into 4 groups (differ in various intake levels of calcium and magnesium in four replications. The maize-wheat-soybean basal diet contained 2.33 g Ca and 1.58 g Mg per kilogram. Calcium was added by CaCO3 and magnesium by MgSO4. Control group (C received feed mixture with added CaCO3 in dose of 19.49 and 0.41 of MgSO4. Three experimental groups contain added CaCO3 in dose of 11.83 and 0 MgSO4 (group Exp1; CaCO3 11.83 and 0.41 MgSO4 (group Exp2; CaCO3 19.49 and 0 MgSO4 (group Exp3, respectively. The feed consumption was daily monitored and the cockerels were weighed twice a week. At the end of the study the experimental animals were weighted and slaughtered by decapitation. The weight of carcasses, liver and proportion of breast and thigh muscle was determined in the selected chickens (n = 24. The atomic absorption spectrometry was used for Ca and Mg evaluation in liver tissues. Bone strength parameter was measured at the femur bone. The statistically significant differences (p >0.05 were not detected between control and experimental groups in the case of studied parameters of fattening, bone strength and calcium and magnesium content in the chicken´s liver. Based on the obtained results it could be concluded the reduction of determined elements in the chicken diet did not deteriorate parameters of yield, elements content in liver tissue as well as the bone strength of broiler chickens. Normal 0 21 false false false CS X-NONE X-NONE

  5. Space flight calcium: implications for astronaut health, spacecraft operations, and Earth. (United States)

    Smith, Scott M; McCoy, Torin; Gazda, Daniel; Morgan, Jennifer L L; Heer, Martina; Zwart, Sara R


    The space flight environment is known to induce bone loss and, subsequently, calcium loss. The longer the mission, generally the more bone and calcium are lost. This review provides a history of bone and calcium studies related to space flight and highlights issues related to calcium excretion that the space program must consider so that urine can be recycled. It also discusses a novel technique using natural stable isotopes of calcium that will be helpful in the future to determine calcium and bone balance during space flight.

  6. Calcium and bone disorders in pregnancy

    Directory of Open Access Journals (Sweden)

    Shriraam Mahadevan


    Full Text Available Significant transplacental calcium transfer occurs during pregnancy, especially during the last trimester, to meet the demands of the rapidly mineralizing fetal skeleton. Similarly, there is an obligate loss of calcium in the breast milk during lactation. Both these result in considerable stress on the bone mineral homeostasis in the mother. The maternal adaptive mechanisms to conserve calcium are different in pregnancy and lactation. During pregnancy, increased intestinal absorption of calcium from the gut mainly due to higher generation of calcitriol (1,25 dihydroxy vitamin D helps in maintaining maternal calcium levels. On the other hand, during lactation, the main compensatory mechanism is skeletal resorption due to increased generation of parathormone related peptide (PTHrP from the breast. Previous studies suggest that in spite of considerable changes in bone mineral metabolism during pregnancy, parity and lactation are not significantly associated with future risk for osteoporosis. However, in India, the situation may not be the same as a significant proportion of pregnancies occur in the early twenties when peak bone mass is not yet achieved. Further, malnutrition, anemia and vitamin D deficiency are commonly encountered in this age group. This may have an impact on future bone health of the mother. It may also probably provide an opportunity for health care providers for prevention. Other metabolic bone diseases like hypoparathyroidism, hyperparathyroidism and pseudohypoparathyroidism are rarely encountered in pregnancy. Their clinical implications and management are also discussed.

  7. Ordering of calcium and vacancies in calcium catapleiite CaZr[Si3O9] • 2H2O

    International Nuclear Information System (INIS)

    Aksenov, S. M.; Portnov, A. M.; Chukanov, N. V.; Rastsvetaeva, R. K.; Nelyubina, Yu. V.; Kononkova, N. N.; Akimenko, M. I.


    A sample of holotypic calcium catapleiite from the Burpala alkaline massif (Northern Baikal, Russia) is studied by single crystal X-ray analysis at 120 K and IR spectroscopy. The empirical formula of calcium catapleiite is Ca 0.97 Na 0.02 Zr 1.01 Si 3 O 9 • 2H 2 O (Z = 4). The X-ray diffraction study confirms the orthorhombic unit cell with the following parameters: a = 7.406(1), b = 12.687(1), and c = 10.112(1) Å; V = 950.1(2) Å 3 ; space group Pbnn. The crystal structure is refined in the anisotropic approximation of atomic displacement parameters using 1177 reflections with I > 2σ(I) to the final R = 2.91%. The structure of calcium catapleiite under study is based on the microporous heteropolyhedral framework formed by ZrO 6 octahedra and threemembered silicon–oxygen rings [Si 3 O 9 ]. It is on the whole analogous to the structures of the samples studied earlier, but differs from them by a high degree of ordering of calcium and vacancies at extraframework positions. The distribution of calcium over Ca1 and Ca2 positions in the calcium catapleiite structure leads to the formation of zigzag chains of the …Ca1–Zr–Ca1–Zr… and …Ca2–h–Ca2–□… types. Low occupancy of the Ca2 position and its alternation with the vacancy are prerequisites for potential Ca 2+ cationic conduction.

  8. Calcium in edible insects and its use in human nutrition

    Directory of Open Access Journals (Sweden)

    Anna Adámková


    Full Text Available Calcium is one of the most problematic substances in human nutrition. Nutrition in the present population is not optimal, because of insufficient consumption of milk and dairy products. Due to the expanding interest of specialists and the general public about entomophagy, as well as increase of the EU interest in this type of food, there is a need to consider the use of edible insects as an alternative source of nutrition. From the perspective of edible insects as a source of calcium, edible insects could be considered as a possible source of calcium for enriching the diet and also as a substitute for people with lactose intolerance and allergies to other categories of foods rich in calcium. Of the six analysed species of edible insect, Bombyx mori had the highest calcium content, almost comparable to semi-skimmed cow's milk. Gryllus assimillis can also be a rich source of calcium as well as other analysed species. The lowest content of calcium was detected in Zophobas morio. Common meat (chicken, beef, pork has lower calcium content comparing with all analysed species of edible insect (Apis mellifera, Bombyx mori, Gryllus assimillis, Locusta migratoria, Tenebrio molitor, Zophobas morio. Therefore, the selected species of edible insect could serve as an alternative source of calcium for people with lactose intolerance and allergies to soy. Phosphorus level in human body is closely related to calcium in the calcium-phosphate metabolism, therefore phosphorus level was detected in these samples too. Bombyx mori had the highest phosphorus content and the lowest content of phosphorus was measured in Zophobas morio samples.

  9. Dose-dependent ATP depletion and cancer cell death following calcium electroporation, relative effect of calcium concentration and electric field strength

    DEFF Research Database (Denmark)

    Hansen, Emilie Louise; Sozer, Esin Bengisu; Romeo, Stefania


    death and could be a novel cancer treatment. This study aims at understanding the relationship between applied electric field, calcium concentration, ATP depletion and efficacy. METHODS: In three human cell lines--H69 (small-cell lung cancer), SW780 (bladder cancer), and U937 (leukaemia), viability...... was observed with fluorescence confocal microscopy of quinacrine-labelled U937 cells. RESULTS: Both H69 and SW780 cells showed dose-dependent (calcium concentration and electric field) decrease in intracellular ATP (p...-dependently reduced cell survival and intracellular ATP. Increasing extracellular calcium allows the use of a lower electric field. GENERAL SIGNIFICANCE: This study supports the use of calcium electroporation for treatment of cancer and possibly lowering the applied electric field in future trials....

  10. Transcriptome wide identification and validation of calcium sensor gene family in the developing spikes of finger millet genotypes for elucidating its role in grain calcium accumulation. (United States)

    Singh, Uma M; Chandra, Muktesh; Shankhdhar, Shailesh C; Kumar, Anil


    In finger millet, calcium is one of the important and abundant mineral elements. The molecular mechanisms involved in calcium accumulation in plants remains poorly understood. Transcriptome sequencing of genetically diverse genotypes of finger millet differing in grain calcium content will help in understanding the trait. In this study, the transcriptome sequencing of spike tissues of two genotypes of finger millet differing in their grain calcium content, were performed for the first time. Out of 109,218 contigs, 78 contigs in case of GP-1 (Low Ca genotype) and out of 120,130 contigs 76 contigs in case of GP-45 (High Ca genotype), were identified as calcium sensor genes. Through in silico analysis all 82 unique calcium sensor genes were classified into eight calcium sensor gene family viz., CaM & CaMLs, CBLs, CIPKs, CRKs, PEPRKs, CDPKs, CaMKs and CCaMK. Out of 82 genes, 12 were found diverse from the rice orthologs. The differential expression analysis on the basis of FPKM value resulted in 24 genes highly expressed in GP-45 and 11 genes highly expressed in GP-1. Ten of the 35 differentially expressed genes could be assigned to three documented pathways involved mainly in stress responses. Furthermore, validation of selected calcium sensor responder genes was also performed by qPCR, in developing spikes of both genotypes grown on different concentration of exogenous calcium. Through de novo transcriptome data assembly and analysis, we reported the comprehensive identification and functional characterization of calcium sensor gene family. The calcium sensor gene family identified and characterized in this study will facilitate in understanding the molecular basis of calcium accumulation and development of calcium biofortified crops. Moreover, this study also supported that identification and characterization of gene family through Illumina paired-end sequencing is a potential tool for generating the genomic information of gene family in non-model species.

  11. Influence of calcium acetate on rye bread volume

    Directory of Open Access Journals (Sweden)

    Katharina FUCKERER


    Full Text Available Abstract The positive accepted savoury taste of rye bread is dependent on acetate concentration in the dough of such breads. In order to study how calcium acetate influences rye bread properties, the pH of rye doughs fortified with calcium acetate and the resulting volume of the breads were measured. Furthermore, CO2 formation of yeast with added calcium acetate and yeast with different pH levels (4, 7, 9 were measured. Thereby, it was determined that the addition of calcium acetate increased the pH of dough from 4.42 to 5.29 and significantly reduced the volume of the breads from 1235.19 mL to 885.52 mL. It could be proven that bread volume was affected by a 30.9% lower CO2 amount production of yeast, although bread volume was not affected by changing pH levels. Due to reduced bread volume, high concentrations of calcium acetate additions are not recommended for improving rye bread taste.

  12. Calcium intake and risk of fracture: systematic review


    Bolland, Mark J; Leung, William; Tai, Vicky; Bastin, Sonja; Gamble, Greg D; Grey, Andrew; Reid, Ian R


    Objective To examine the evidence underpinning recommendations to increase calcium intake through dietary sources or calcium supplements to prevent fractures. Design Systematic review of randomised controlled trials and observational studies of calcium intake with fracture as an endpoint. Results from trials were pooled with random effects meta-analyses. Data sources Ovid Medline, Embase, PubMed, and references from relevant systematic reviews. Initial searches undertaken in July 2013 and upd...

  13. Monitoring Calcium in Trout Eggs Exposed to Hydrazine. (United States)


    healthy muscle of the same individual. The notochord of the 8.0 mg/P group showed a higher calcium level than the control group. The chorion did not...calcium in quantities that can be monitored with conventional instru- ments or techniques. The chorion, muscle and notochord tissues were the primary...deposits of calcium pyorantimonate (Figure 26), supported the findings of the microelemental analysis. NOTOCHORD 1. Control The notochord of control embryos

  14. Calcium and vitamin D in post menopausal women

    Directory of Open Access Journals (Sweden)

    Sameer Aggarwal


    Full Text Available Calcium and Vitamin D are widely used therapies for Osteoporosis. Vitamin D is not a vitamin in true sense since it is produced in response to the action of sunlight on skin. Vitamin D has multiple roles in the body, not all of them well-understood. Vitamin D supplementation must be considered a form of hormone replacement therapy. Therefore it raises all the questions about efficacy, dose, and side effects. The Efficacy of use of Calcium and Vitamin D in all post menopausal women in terms of the prevention of fracture is uncertain. The Annual worldwide sales of these supplements have been several billion dollars. The variation of the results from various studies of Calcium and Vitamin D supplementation in elderly women suggest that benefit of calcium plus vitamin D on bone mineral density or the risk of fracture is small and may vary from group to group and baseline Vitamin D status. Women taking supplemental vitamin D and calcium have a statistically increased incidence of renal stones, according to evidence from the Women′s Health Initiative. Studies have shown association between calcium use and increased risk for cardiovascular disease. In a recent review of evidence from 6 randomized trials evaluating the use of vitamin D and calcium to prevent fractures in postmenopausal women who are not living in a nursing home or other institution, the United States Preventive Task Force (USPTF found no evidence of a benefit from supplementation with 400 IU or less of vitamin D3 and 1000 mg or less of calcium. Also in a report from institute of Medicine Committee, there was insufficient evidence, particularly from randomized trials, that vitamin D treatment affected the risk of non skeletal outcomes like risk of cancer, cardiovascular disease, diabetes, infections, autoimmune disease, and other extra skeletal outcomes.

  15. Pyrochemical recovery of plutonium from calcium fluoride reduction slag (United States)

    Christensen, D.C.

    A pyrochemical method of recovering finely dispersed plutonium metal from calcium fluoride reduction slag is claimed. The plutonium-bearing slag is crushed and melted in the presence of at least an equimolar amount of calcium chloride and a few percent metallic calcium. The calcium chloride reduces the melting point and thereby decreases the viscosity of the molten mixture. The calcium reduces any oxidized plutonium in the mixture and also causes the dispersed plutonium metal to coalesce and settle out as a separate metallic phase at the bottom of the reaction vessel. Upon cooling the mixture to room temperature, the solid plutonium can be cleanly separated from the overlying solid slag, with an average recovery yield on the order of 96 percent.

  16. Comparison of Serum Calcium and Magnesium Between ...

    African Journals Online (AJOL)

    Background: Evidence suggests the involvement of calcium and magnesium metabolism in the pathophysiology of preeclampsia. However, findings from studies are heterogenous and inconsistent. Aim: The study aimed to compare the total serum calcium and magnesium levels in preeclamptic women with that of ...

  17. Flow rate, pH and calcium concentration of saliva of children and adolescents with type 1 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    A.R. Moreira


    Full Text Available Alterations in salivary parameters may increase the caries risk in diabetic children, but, contradictory data on this issue have been reported. The aims of this study were to compare salivary parameters (flow rate, pH and calcium concentration between healthy and type 1 diabetes mellitus (T1DM individuals. The sample consisted of 7- to 18-year-old individuals divided into two groups: 30 subjects with T1DM (group A and 30 healthy control subjects (group B. Fasting glucose levels were determined. Unstimulated and stimulated saliva was collected. The pH of unstimulated saliva was measured with paper strips and an electrode. Calcium concentrations in stimulated saliva were determined with a selective electrode. Group A individuals had inadequate blood glucose control (HbA1C >9%, with means ± SD unstimulated salivary flow rate of 0.15 ± 0.1 mL/min compared to 0.36 ± 0.2 mL/min for group B (P < 0.01. Stimulated salivary flow rate was similar by both groups and above 2.0 mL/min. Saliva pH was 6.0 ± 0.8 for group A and significantly different from 7.0 ± 0.6 for group B (P < 0.01. Salivary calcium was 14.7 ± 8.1 mg/L for group A and significantly higher than 9.9 ± 6.4 mg/L for group B (P < 0.01. Except for elevated calcium concentrations in saliva, salivary parameters favoring caries such as low saliva pH and unstimulated salivary flow rate were observed in T1DM individuals.

  18. Calcium-deficiency assessment and biomarker identification by an integrated urinary metabonomics analysis (United States)


    Background Calcium deficiency is a global public-health problem. Although the initial stage of calcium deficiency can lead to metabolic alterations or potential pathological changes, calcium deficiency is difficult to diagnose accurately. Moreover, the details of the molecular mechanism of calcium deficiency remain somewhat elusive. To accurately assess and provide appropriate nutritional intervention, we carried out a global analysis of metabolic alterations in response to calcium deficiency. Methods The metabolic alterations associated with calcium deficiency were first investigated in a rat model, using urinary metabonomics based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry and multivariate statistical analysis. Correlations between dietary calcium intake and the biomarkers identified from the rat model were further analyzed to confirm the potential application of these biomarkers in humans. Results Urinary metabolic-profiling analysis could preliminarily distinguish between calcium-deficient and non-deficient rats after a 2-week low-calcium diet. We established an integrated metabonomics strategy for identifying reliable biomarkers of calcium deficiency using a time-course analysis of discriminating metabolites in a low-calcium diet experiment, repeating the low-calcium diet experiment and performing a calcium-supplement experiment. In total, 27 biomarkers were identified, including glycine, oxoglutaric acid, pyrophosphoric acid, sebacic acid, pseudouridine, indoxyl sulfate, taurine, and phenylacetylglycine. The integrated urinary metabonomics analysis, which combined biomarkers with regular trends of change (types A, B, and C), could accurately assess calcium-deficient rats at different stages and clarify the dynamic pathophysiological changes and molecular mechanism of calcium deficiency in detail. Significant correlations between calcium intake and two biomarkers, pseudouridine (Pearson

  19. Dietary calcium intake and sunlight exposure among children aged ...

    African Journals Online (AJOL)

    Nutritional rickets can be caused by either or both calcium and vitamin D deficiencies, and can frequently occur in Africa. In Ethiopia, limited evidence exists regarding the calcium intake of children and their sunlight exposure practices. The purpose of this study was to assess information regarding dietary calcium intake and ...

  20. Calcium isotope ratios in animal and human bone (United States)

    Reynard, L. M.; Henderson, G. M.; Hedges, R. E. M.


    Calcium isotopes in tissues are thought to be influenced by an individual's diet, reflecting parameters such as trophic level and dairy consumption, but this has not been carefully assessed. We report the calcium isotope ratios (δ 44/42Ca) of modern and archaeological animal and human bone ( n = 216). Modern sheep raised at the same location show 0.14 ± 0.08‰ higher δ 44/42Ca in females than in males, which we attribute to lactation by the ewes. In the archaeological bone samples the calcium isotope ratios of the herbivorous fauna vary by location. At a single site, the archaeological fauna do not show a trophic level effect. Humans have lower δ 44/42Ca than the mean site fauna by 0.22 ± 0.22‰, and the humans have a greater δ 44/42Ca range than the animals. No effect of sex or age on the calcium isotope ratios was found, and intra-individual skeletal δ 44/42Ca variability is negligible. We rule out dairy consumption as the main cause of the lower human δ 44/42Ca, based on results from sites pre-dating animal domestication and dairy availability, and suggest instead that individual physiology and calcium intake may be important in determining bone calcium isotope ratios.

  1. Altered elementary calcium release events and enhanced calcium release by thymol in rat skeletal muscle. (United States)

    Szentesi, Péter; Szappanos, Henrietta; Szegedi, Csaba; Gönczi, Monika; Jona, István; Cseri, Julianna; Kovács, László; Csernoch, László


    The effects of thymol on steps of excitation-contraction coupling were studied on fast-twitch muscles of rodents. Thymol was found to increase the depolarization-induced release of calcium from the sarcoplasmic reticulum, which could not be attributed to a decreased calcium-dependent inactivation of calcium release channels/ryanodine receptors or altered intramembrane charge movement, but rather to a more efficient coupling of depolarization to channel opening. Thymol increased ryanodine binding to heavy sarcoplasmic reticulum vesicles, with a half-activating concentration of 144 micro M and a Hill coefficient of 1.89, and the open probability of the isolated and reconstituted ryanodine receptors, from 0.09 +/- 0.03 to 0.22 +/- 0.04 at 30 micro M. At higher concentrations the drug induced long-lasting open events on a full conducting state. Elementary calcium release events imaged using laser scanning confocal microscopy in the line-scan mode were reduced in size, 0.92 +/- 0.01 vs. 0.70 +/- 0.01, but increased in duration, 56 +/- 1 vs. 79 +/- 1 ms, by 30 micro M thymol, with an increase in the relative proportion of lone embers. Higher concentrations favored long events, resembling embers in control, with duration often exceeding 500 ms. These findings provide direct experimental evidence that the opening of a single release channel will generate an ember, rather than a spark, in mammalian skeletal muscle.

  2. Model of Inclusion Evolution During Calcium Treatment in the Ladle Furnace (United States)

    Tabatabaei, Yousef; Coley, Kenneth S.; Irons, Gordon A.; Sun, Stanley


    Calcium treatment of steel is typically employed to modify alumina inclusions to liquid calcium aluminates. However, injected calcium also reacts with the dissolved sulfur to form calcium sulfide. The current work aims to develop a kinetic model for the evolution of oxide and sulfide inclusions in Al-killed alloyed steel during Ca treatment in the ladle refining process. The model considers dissolution of the calcium from the calcium bubbles into the steel and reduction of calcium oxide in the slag to dissolved calcium. A steel-inclusion kinetic model is used for mass transfer to the inclusion interface and diffusion within the calcium aluminate phases formed on the inclusion. The inclusion-steel kinetic model is then coupled with a previously developed steel-slag kinetic model. The coupled inclusion-steel-slag kinetic model is applied to the chemical composition changes in molten steel, slag, and evolution of inclusions in the ladle. The result of calculations is found to agree well with an industrial heat for species in the steel as well as inclusions during Ca treatment.

  3. Historieportal 3.-6. -

    DEFF Research Database (Denmark)

    Poulsen, Jens Aage

    Portal, der indeholder tekster, video, billeder, interaktive opgaver m.m. til undervisningen i historie i 3.-6. klasse......Portal, der indeholder tekster, video, billeder, interaktive opgaver m.m. til undervisningen i historie i 3.-6. klasse...


    African Journals Online (AJOL)

    Furthermore, the controversy over the role of calci~-channel blockers as first-line ..... group trials while fully accounting for placebo effects as well as interindividual ..... Reducing calcium overload in the ischemic brain. N Engl JMed. 1999; 341 ...

  5. Calcium Blood Test: MedlinePlus Lab Test Information (United States)

    ... K. Brunner & Suddarth's Handbook of Laboratory and Diagnostic Tests. 2 nd Ed, Kindle. Philadelphia: Wolters Kluwer Health, Lippincott Williams & Wilkins; c2014. Calcium, Serum; Calcium and Phosphates, Urine; ...

  6. Effects of Eggshell Calcium Supplementation on Bone Mass in Postmenopausal Vietnamese Women. (United States)

    Sakai, Seigo; Hien, Vu Thi Thu; Tuyen, Le Danh; Duc, Ha Anh; Masuda, Yasunobu; Yamamoto, Shigeru


    Bone mass decreases along with aging, especially for women after menopause because of lower estrogen secretion together with low calcium intake. This study was conducted to study the effect of eggshell calcium supplementation on bone mass in 54 postmenopausal Vietnamese women living in a farming area about 60 km from Hanoi, Vietnam. Sets of 3 subjects matched by age, bone mass, BMI and calcium intake were divided randomly into 3 groups with 18 subjects in each group. The eggshell calcium group was administered 300 mg/d calcium from eggshell, the calcium carbonate group 300 mg/d calcium from calcium carbonate and the placebo group received no calcium supplementation. Bone mass (Speed of Sound (SOS)) was measured at the beginning (the baseline), the middle (6th month) and the end of the study (12th month) by the single blind method. SOS of the eggshell group increased significantly at 12 mo (p0.05). In conclusion, eggshell calcium was more effective in increasing bone mass than calcium carbonate in postmenopausal Vietnamese women.

  7. Milrinone and levosimendan during porcine myocardial ischemia -- no effects on calcium overload and metabolism. (United States)

    Axelsson, B; Johansson, G; Abrahamsson, P; Gupta, A; Tydén, H; Wouters, P; Haney, M


    Although inotropic stimulation is considered harmful in the presence of myocardial ischaemia, both calcium sensitisers and phosphodiesterase inhibitors may offer cardioprotection. We hypothesise that these cardioprotective effects are related to an acute alteration of myocardial metabolism. We studied in vivo effects of milrinone and levosimendan on calcium overload and ischaemic markers using left ventricular microdialysis in pigs with acute myocardial ischaemia. Anaesthetised juvenile pigs, average weight 36 kg, were randomised to one of three intravenous treatment groups: milrinone 50 μg/kg bolus plus infusion 0.5 μg/kg/min (n = 7), levosimendan 24 μg/kg plus infusion 0.2 μg/kg/min (n = 7), or placebo (n = 6) for 60 min prior to and during a 45 min acute regional coronary occlusion. Systemic and myocardial haemodynamics were assessed, and microdialysis was performed with catheters positioned in the left ventricular wall. (45) Ca(2+) was included in the microperfusate in order to assess local calcium uptake into myocardial cells. The microdialysate was analysed for glucose, lactate, pyruvate, glycerol, and for (45) Ca(2+) recovery. During ischaemia, there were no differences in microdialysate-measured parameters between control animals and milrinone- or levosimendan-treated groups. In the pre-ischaemic period, arterial blood pressure decreased in all groups while myocardial oxygen consumption remained stable. These findings reject the hypothesis of an immediate energy-conserving effect of milrinone and levosimendan during acute myocardial ischaemia. On the other hand, the data show that inotropic support with milrinone and levosimendan does not worsen the metabolic parameters that were measured in the ischaemic myocardium. © 2013 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  8. Evaluation of alternative methods for coronary calcium scoring in multi-detector-row computed tomography

    International Nuclear Information System (INIS)

    Serafin, Z.; Lasek, W.; Laskowska, K.; Marzec, M.


    Determining coronary artery calcifications is one of the methods of coronary heart disease screening. However, the traditional Agatston Calcium Score (CS) shows low interexamination reproducibility. The aim of this study was to evaluate the interscan variability coefficients of calcium measures based on three modifications of the original Agatston equation. Fifty adults (37 men and 13 women; mean age 46.2 ± 9.2 years) were included in the study. Each patient was examined with two consecutive, prospectively electrocardiographically triggered, multi-detector-row CT acquisitions to detect and quantify coronary artery calcifications. CS was calculated according to the method by Agatston et al. Alternative scores were calculated using a continuous weighting factor (CS-CM), the average lesion attenuation value (CS-SA), or both (CS-CA). The mean and median interscan percent variabilities of the methods were evaluated using nonparametric analysis of variance. In the 50 patients, 1315 calcified lesions were found. The alternative scores correlated well with CS (for CS vs. CS-SA, CS-CM, and CS-CA, r = 0.990, 0.840, and 0.946, respectively, P < 0.0001). The mean and median percent variabilities did not differ significantly among the methods tested (P = 0.370). For CS, CS-SA, CS-CM, and CS-CA the mean variabilities were 13.24%, 13.36%, 16.00%, and 13.62%, respectively. Except for CS-CM, the methods showed similar distributions of variability vs. score on Bland and Altman plots. None of the tested modifications of the Agatston method brought improvement in the interscan reproducibility of coronary calcium scoring. In our opinion, a significant reduction in variability may be achieved by a standardization of image acquisition and reconstruction. (author)


    NARCIS (Netherlands)



    Diet is a major determinant of colon cancer risk. Calcium may protect against colon cancer, presumably by binding cytotoxic bile acids and fatty acids. Numerous studies support this proposition. In subjects at risk for colon cancer oral calcium supplementation has been shown to reduce rectal

  10. Rates of calcium carbonate removal from soils.

    NARCIS (Netherlands)

    Breemen, van N.; Protz, R.


    Mean annual rates of calcium carbonate removal from soils in a subarctic climate estimated from data on two chronosequences of calcareous storm ridges, appeared to be relatively constant through time. Concentrations of dissolved calcium carbonate in the soil solution in the study sites calculated

  11. Carbon Dioxide Adsorption by Calcium Zirconate at Higher Temperature

    Directory of Open Access Journals (Sweden)

    K. B. Kale


    Full Text Available The CO2 adsorption by calcium zirconate was explored at pre- and post- combustion temperature condition. The several samples of the calcium zirconate were prepared by different methods such as sol-gel, solid-solid fusion, template and micro-emulsion. The samples of the calcium zirconate were characterized by measurement of surface area, alkalinity/acidity, and recording the XRD patterns and SEM images. The CO2 adsorptions by samples of the calcium zirconate were studied in the temperature range 100 to 850 oC and the CO2 adsorptions were observed in the ranges of 6.88 to 40.6 wt % at 600 0C and 8 to 16.82 wt% at in between the temperatures 200 to 300 oC. The effect of Ca/Zr mol ratio in the samples of the calcium zirconate on the CO2 adsorption and alkalinity were discussed. The adsorbed moisture by the samples of the calcium zirconate was found to be useful for the CO2 adsorption. The promoted the samples of the calcium zirconate by K+, Na+, Rb+, Cs+, Ag+ and La3+ showed the increased CO2 adsorption. The exposure time of CO2 on the samples of the calcium zirconate showed the increased CO2 adsorption. The samples of the calcium zirconate were found to be regenerable and reusable several times for the adsorption of CO2 for at the post- and pre-combustion temperature condition. Copyright © 2012 by BCREC Undip. All rights reservedReceived: 23rd June 2012, Revised: 28th August 2012, Accepted: 30th August 2012[How to Cite: K. B. Kale, R. Y. Raskar, V. H. Rane and A. G.  Gaikwad (2012. Carbon Dioxide Adsorption by Calcium Zirconate at Higher Temperature. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (2: 124-136. doi:10.9767/bcrec.7.2.3686.124-136] [How to Link / DOI: ] | View in 

  12. Plasma oxalic acid and calcium levels in oxalate poisoning (United States)

    Zarembski, P. M.; Hodgkinson, A.


    Observations are reported on five cases of suicide or attempted suicide by poisoning with oxalic acid or ethylene glycol. Elevated oxalic acid levels were observed in the plasma, stomach contents, and a number of tissues. Raised oxalic acid levels in plasma were associated with reduced total and ultrafilterable calcium levels. It is suggested that the reduction in plasma total calcium level is due mainly to the deposition of calcium oxalate in the soft tissues, but inhibition of the parathyroid glands may be a contributory factor. Microscopic examination of various tissues indicated that oxalic acid is deposited in the tissues in two forms: (1) crystalline calcium oxalate dihydrate in the kidney and (2) a non-crystalline complex of calcium oxalate and lipid in liver and other tissues. PMID:5602563

  13. Mechanically induced intracellular calcium waves in osteoblasts demonstrate calcium fingerprints in bone cell mechanotransduction. (United States)

    Godin, Lindsay M; Suzuki, Sakiko; Jacobs, Christopher R; Donahue, Henry J; Donahue, Seth W


    An early response to mechanical stimulation of bone cells in vitro is an increase in intracellular calcium concentration ([Ca (2+)](i)). This study analyzed the [Ca (2+)](i) wave area, magnitude, duration, rise time, fall time, and time to onset in individual osteoblasts for two identical bouts of mechanical stimulation separated by a 30-min rest period. The area under the [Ca (2+)](i) wave increased in the second loading bout compared to the first. This suggests that rest periods may potentiate mechanically induced intracellular calcium signals. Furthermore, many of the [Ca (2+)](i) wave parameters were strongly, positively correlated between the two bouts of mechanical stimulation. For example, in individual primary osteoblasts, if a cell had a large [Ca (2+)](i) wave area in the first bout it was likely to have a large [Ca (2+)](i) wave area in the second bout (r (2) = 0.933). These findings support the idea that individual bone cells have "calcium fingerprints" (i.e., a unique [Ca (2+)](i) wave profile that is reproducible for repeated exposure to a given stimulus).

  14. The Effect of Cell Immobilization by Calcium Alginate on Bacterially Induced Calcium Carbonate Precipitation

    Directory of Open Access Journals (Sweden)

    Mostafa Seifan


    Full Text Available Microbially induced mineral precipitation is recognized as a widespread phenomenon in nature. A diverse range of minerals including carbonate, sulphides, silicates, and phosphates can be produced through biomineralization. Calcium carbonate (CaCO3 is one of the most common substances used in various industries and is mostly extracted by mining. In recent years, production of CaCO3 by bacteria has drawn much attention because it is an environmentally- and health-friendly pathway. Although CaCO3 can be produced by some genera of bacteria through autotrophic and heterotrophic pathways, the possibility of producing CaCO3 in different environmental conditions has remained a challenge to determine. In this study, calcium alginate was proposed as a protective carrier to increase the bacterial tolerance to extreme environmental conditions. The model showed that the highest concentration of CaCO3 is achieved when the bacterial cells are immobilized in the calcium alginate beads fabricated using 1.38% w/v Na-alginate and 0.13 M CaCl2.

  15. Calcium balance in young adults on a vegan and lactovegetarian diet. (United States)

    Kohlenberg-Mueller, Kathrin; Raschka, Ladislav


    For people in Western countries, the vegan diet has the advantage of low energy intake, but the calcium status of this strictly plant-based diet is still unclear. The aim of this study was to determine the calcium balance of individuals on a vegan diet in comparison with a lactovegetarian diet in a short-term investigation. Seven women and one man, ranging in age from 19 to 24 years, received during the first 10 days a vegan diet based on plant foods and calcium-rich mineral water and a lactovegetarian diet during the following 10 days. Portion size was adapted to the subjects' individual energy requirements. Calcium status was assessed by means of calcium intake in food and calcium output in feces and urine as measured by flame atomic absorption spectrophotometry. In addition, deoxypyridinoline was measured in urine as a marker of bone resorption. The results show a significantly smaller daily calcium intake with an average of 843 +/- 140 mg in the vegan versus 1322 +/- 303 mg in the lactovegetarian diet. Apparent calcium absorption rates were calculated as 26% +/- 15% in the vegan and 24% +/- 8% in the lactovegetarian group (NS). The calcium balance was positive both in the vegan diet (119 +/- 113 mg/day) and in the lactovegetarian diet (211 +/- 136 mg/day) (NS). Deoxypyridinoline excretion showed no significant difference between the two diets (105 +/- 31 and 98 +/- 23 nmol/day). The present results indicate that calcium balance and a marker of bone turnover are not affected significantly when calcium is provided either solely by plant foods or by a diet including dairy products, despite the significantly different calcium intake levels in the diets. We conclude that a well-selected vegan diet maintains calcium status, at least for a short-term period.

  16. Variations in Calcium and Alginate Ions Concentration in Relation to the Properties of Calcium Alginate Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hamed Daemi


    Full Text Available Alginate belongs to a group of natural polymers called polysaccharides. They have carboxylic functional groups beside hydroxyls which are common in all polysaccharides. These materials show interesting properties due to theirfunctional groups. One of these properties is the ability of this polymer as a suitable carrier of protecting and transferring drugs and biomolecules. The particle sizes of these polymers are very important for their applications, so different techniques were used for preparation of these materials. In this way polymeric nanoparticles of calcium alginate which are excellent carriers in drug delivery systems were prepared by addition of calcium chloride solution to dilute solution of sodium alginate. Investigation of the size and distribution of nanoparticles were analyzed by SEM method. The concentration effects of both alginate and calcium ions on the size and distribution of  nanoparticles were studied in this research. Results showed that the size of nanoparticles obviously decreased with decreasing polymeric alginate concentration because of lower active sites in polymer chain. On the other hand, thesize and distribution of nanoparticles are significantly improved with increase of calcium cation concentrations. The mean particle size 40-70 nm and spherical shape are the main characteristics of the prepared nanoparticles.

  17. 226Ra, 210Pb and calcium in eyes of long-term radium cases

    International Nuclear Information System (INIS)

    Holtzman, R.B.; Sha, J.Y.; Plondke, N.J.


    It is known that dogs injected with radium accumulate a significant fraction of this element in the eye, with consequent radiation damage. We are interested in looking for similar concentrations in the human eye. An eye from each of two radium cases (01-144 and 01-017) with body burdens of 690 and 1210 nCi 226 Ra, respectively, was analyzed for 226 Ra, 210 Pb and calcium. The total amounts in the eyes were 1.80 pCi 226 Ra, 1.3 pCi 210 Pb and 2.3 mg of calcium in Case 01-144 and 5.4 pCi 226 Ra, 3.6 pCi 210 Pb and 14.2 mg of calcium in Case 01-017. For the latter case the eye was dissected and showed the highest 226 Ra concentrations (on a wet weight basis) in the choroid (3.8 pCi/g), sclera (3.4 pCi/g) and iris (2.9 pCi/g). The radium content was 2.7 x 10 -4 % to 4.7 x 10 -4 % of the total body content at 50 to 55 years after first exposure. The 226 Ra/Ca ratios in the whole eye were 1/3 to 1/4 those in the whole body, but that for the choroid from the dissected eye was identical to that of the whole body. For 210 Pb the concentrations in the various parts of the eye were similar to and correlated with those of the 226 Ra. The 210 Pb/Ca ratios in the eye are comparable to those of the whole body, which indicates that the eye concentrates 210 Pb relative to 226 Ra. These data will be compared to those from the dog and the differences will be discussed. (author)

  18. Activation of purified calcium channels by stoichiometric protein phosphorylation

    Energy Technology Data Exchange (ETDEWEB)

    Nunoki, K.; Florio, V.; Catterall, W.A. (Univ. of Washington, Seattle (USA))


    Purified dihydropyridine-sensitive calcium channels from rabbit skeletal muscle were reconstituted into phosphatidylcholine vesicles to evaluate the effect of phosphorylation by cyclic AMP-dependent protein kinase (PK-A) on their function. Both the rate and extent of {sup 45}Ca{sup 2+} uptake into vesicles containing reconstituted calcium channels were increased severalfold after incubation with ATP and PK-A. The degree of stimulation of {sup 45}Ca{sup 2+} uptake was linearly proportional to the extent of phosphorylation of the alpha 1 and beta subunits of the calcium channel up to a stoichiometry of approximately 1 mol of phosphate incorporated into each subunit. The calcium channels activated by phosphorylation were determined to be incorporated into the reconstituted vesicles in the inside-out orientation and were completely inhibited by low concentrations of dihydropyridines, phenylalkylamines, Cd{sup 2+}, Ni{sup 2+}, and Mg{sup 2+}. The results demonstrate a direct relationship between PK-A-catalyzed phosphorylation of the alpha 1 and beta subunits of the purified calcium channel and activation of the ion conductance activity of the dihydropyridine-sensitive calcium channels.

  19. Activation of purified calcium channels by stoichiometric protein phosphorylation

    International Nuclear Information System (INIS)

    Nunoki, K.; Florio, V.; Catterall, W.A.


    Purified dihydropyridine-sensitive calcium channels from rabbit skeletal muscle were reconstituted into phosphatidylcholine vesicles to evaluate the effect of phosphorylation by cyclic AMP-dependent protein kinase (PK-A) on their function. Both the rate and extent of 45 Ca 2+ uptake into vesicles containing reconstituted calcium channels were increased severalfold after incubation with ATP and PK-A. The degree of stimulation of 45 Ca 2+ uptake was linearly proportional to the extent of phosphorylation of the alpha 1 and beta subunits of the calcium channel up to a stoichiometry of approximately 1 mol of phosphate incorporated into each subunit. The calcium channels activated by phosphorylation were determined to be incorporated into the reconstituted vesicles in the inside-out orientation and were completely inhibited by low concentrations of dihydropyridines, phenylalkylamines, Cd 2+ , Ni 2+ , and Mg 2+ . The results demonstrate a direct relationship between PK-A-catalyzed phosphorylation of the alpha 1 and beta subunits of the purified calcium channel and activation of the ion conductance activity of the dihydropyridine-sensitive calcium channels


    Directory of Open Access Journals (Sweden)

    S. Kismiati


    Full Text Available The research was aimed to evaluate the performance of laying hens fed different calcium sources. Two hundreds of Isa Brown laying hens were used in this study. The hens were raised in individual battery cages units for 12 weeks. Four calcium source (limestone as a control, 5% limestone + 2.5% eggshells waste, 2.5% limestone + 5% eggshells waste and 7.5% eggshell waste were used in feed experiment. A completely randomized design was applied, with 4 treatments and 5 replications. Each experimental unit consisted of 10 laying hens. The parameters measured were feed intake, protein intake, calcium intake, phosphorus intake, egg production, egg weight and feed conversion ratio. Results of the research showed that the calcium source had significantly effect on performance productions. The use of eggshell waste 7.5% significantly increased the feed intake, calcium intake, phosphorus intake, egg production and egg weight except for feed conversion ratio. The conclusion of this research was that the use of eggshell waste as calcium source of feed resulted in better performance than using limestone or mixed limestone with eggshell waste.

  1. Cellular Architecture Regulates Collective Calcium Signaling and Cell Contractility.

    Directory of Open Access Journals (Sweden)

    Jian Sun


    Full Text Available A key feature of multicellular systems is the ability of cells to function collectively in response to external stimuli. However, the mechanisms of intercellular cell signaling and their functional implications in diverse vascular structures are poorly understood. Using a combination of computational modeling and plasma lithography micropatterning, we investigate the roles of structural arrangement of endothelial cells in collective calcium signaling and cell contractility. Under histamine stimulation, endothelial cells in self-assembled and microengineered networks, but not individual cells and monolayers, exhibit calcium oscillations. Micropatterning, pharmacological inhibition, and computational modeling reveal that the calcium oscillation depends on the number of neighboring cells coupled via gap junctional intercellular communication, providing a mechanistic basis of the architecture-dependent calcium signaling. Furthermore, the calcium oscillation attenuates the histamine-induced cytoskeletal reorganization and cell contraction, resulting in differential cell responses in an architecture-dependent manner. Taken together, our results suggest that endothelial cells can sense and respond to chemical stimuli according to the vascular architecture via collective calcium signaling.

  2. Calcium hydroxide suppresses Porphyromonas endodontalis lipopolysaccharide-induced bone destruction. (United States)

    Guo, J; Yang, D; Okamura, H; Teramachi, J; Ochiai, K; Qiu, L; Haneji, T


    Porphyromonas endodontalis and its main virulence factor, lipopolysaccharide (LPS), are associated with the development of periapical diseases and alveolar bone loss. Calcium hydroxide is commonly used for endodontic therapy. However, the effects of calcium hydroxide on the virulence of P. endodontalis LPS and the mechanism of P. endodontalis LPS-induced bone destruction are not clear. Calcium hydroxide rescued the P. endodontalis LPS-suppressed viability of MC3T3-E1 cells and activity of nuclear factor-κB (NF-κB) in these cells, resulting in the reduced expression of interleukin-6 and tumor necrosis factor-α. In addition, calcium hydroxide inhibited P. endodontalis LPS-induced osteoclastogenesis by decreasing the activities of NF-κB, p38, and ERK1/2 and the expression of nuclear factor of activated T-cell cytoplasmic 1 in RAW264.7 cells. Calcium hydroxide also rescued the P. endodontalis LPS-induced osteoclastogenesis and bone destruction in mouse calvaria. Taken together, our present results indicate that calcium hydroxide suppressed bone destruction by attenuating the virulence of P. endodontalis LPS on bone cells.

  3. Recovery of calcium from the effluent of direct oxide reduction process

    International Nuclear Information System (INIS)

    Ferro, P.; Mishra, B.; Olson, D.L.; Moore, J.J.; Averill, W.A.


    This paper reports that the production of plutonium by Direct Oxide Reduction [DOR] process using calcium generates significant amount of contaminated waste as calcium oxide saturated calcium chloride salt mix with calcium oxide content of up to 15 wt. pct. Fused salt electrolysis of a simulated slat mix [CaCl 2 + 15 wt. pct. CaO] is being carried out to election calcium, which can be recycled to the DOR rector along with the calcium chloride salt or may be used in-situ in an combined DOR and electrowinning process. The technology will resolve a major contaminated waste disposal problem, besides improving the cost and process efficiency in radioactive metal production. The process is being optimized in terms of the calcium solubility, cell temperature, current density and cell design to maximize the current efficiency. Scattered information is available regarding the solubility of calcium in calcium chloride salt in the present of calcium oxide. The solubility has also been found to depend on the use of graphite as the anode material. A porous ceramic sheath is being used around the anode to prevent the dissolution of electrowon calcium as oxide or carbonate and to prevent the contamination of salt by the anodic carbon. The electrode reactions are affected by the electrolyte composition and its viscosity which varies with time in this process and, therefore, electrochemical impedance is being measured to understand this time-dependent mechanisms

  4. Effects of calcium-fortified ice cream on markers of bone health. (United States)

    Ferrar, L; van der Hee, R M; Berry, M; Watson, C; Miret, S; Wilkinson, J; Bradburn, M; Eastell, R


    Premenopausal women with low calcium intakes consumed calcium-fortified ice cream daily for 28 days. Bone markers, NTX, CTX and PTH decreased significantly by 7 days, with some evidence of a calcium dose-dependent effect. Bone marker responses were observed within 1 h of consuming ice cream. Body weight remained constant over 28 days. Dietary calcium is important for lifelong bone health. Milk is a good source of bioavailable calcium, but consumption has declined among young adults. The aims were to determine whether calcium-fortified ice cream, a palatable source of calcium, produces significant, sustainable changes in bone turnover markers and parathyroid hormone (PTH) in premenopausal women with calcium intake below recommended UK levels. Eighty women, ages 20-39 years (calcium intake ice cream containing 96, 244, 459 or 676 mg calcium daily for 28 days. Urinary NTX/Cr, serum CTX, PINP, 1,25D and PTH were measured (baseline, days 1, 7 and 28). Acute changes in CTX and PTH were measured over 5 h (n = 29 women). There were significant mean decreases by 7 days in NTX/Cr, CTX, PTH and 1,25D and increases in PINP (one sample t tests), with a significant dose-dependent effect on CTX analysis of covariance. Only CTX remained suppressed at 28 days. Serum CTX and PTH decreased within 1 h. Body weight did not change significantly between baseline and 28 days. Daily consumption of calcium-fortified ice cream by premenopausal women may significantly reduce levels of the bone resorption marker serum CTX, without stimulating weight gain. The ice cream could be incorporated into the diet to replace low-calcium snacks and thus help individuals with habitually low calcium intakes to meet recommended intakes. The 244 mg calcium preparation would provide more than a quarter of the UK daily recommended nutrient intake for premenopausal women.

  5. The functions of store-operated calcium channels. (United States)

    Putney, James W; Steinckwich-Besançon, Natacha; Numaga-Tomita, Takuro; Davis, Felicity M; Desai, Pooja N; D'Agostin, Diane M; Wu, Shilan; Bird, Gary S


    Store-operated calcium channels provide calcium signals to the cytoplasm of a wide variety of cell types. The basic components of this signaling mechanism include a mechanism for discharging Ca 2+ stores (commonly but not exclusively phospholipase C and inositol 1,4,5-trisphosphate), a sensor in the endoplasmic reticulum that also serves as an activator of the plasma membrane channel (STIM1 and STIM2), and the store-operated channel (Orai1, 2 or 3). The advent of mice genetically altered to reduce store-operated calcium entry globally or in specific cell types has provided important tools to understand the functions of these widely encountered channels in specific and clinically important physiological systems. This review briefly discusses the history and cellular properties of store-operated calcium channels, and summarizes selected studies of their physiological functions in specific physiological or pathological contexts. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech. Published by Elsevier B.V.

  6. Calcium and Nuclear Signaling in Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Ivan V. Maly


    Full Text Available Recently, there have been a number of developments in the fields of calcium and nuclear signaling that point to new avenues for a more effective diagnosis and treatment of prostate cancer. An example is the discovery of new classes of molecules involved in calcium-regulated nuclear import and nuclear calcium signaling, from the G protein-coupled receptor (GPCR and myosin families. This review surveys the new state of the calcium and nuclear signaling fields with the aim of identifying the unifying themes that hold out promise in the context of the problems presented by prostate cancer. Genomic perturbations, kinase cascades, developmental pathways, and channels and transporters are covered, with an emphasis on nuclear transport and functions. Special attention is paid to the molecular mechanisms behind prostate cancer progression to the malignant forms and the unfavorable response to anti-androgen treatment. The survey leads to some new hypotheses that connect heretofore disparate results and may present a translational interest.

  7. Separation of calcium isotopes with cryptand complexes

    International Nuclear Information System (INIS)

    Heumann, K.G.; Schiefer, H.P.


    The calcium isotope separation in the liquid-liquid extraction system H 2 O/CHCl 3 is investigated using and cryptands for complex formation as well as without complexing agent. An extraction procedure is used which allows the transfer of larger amounts of calcium in the H 2 O phase. Without complexing agent in the extraction system, enrichment of the lighter calcium isotopes is already evident in the CHCl 3 phase which is just the same as when using cryptand. In the case of cryptand as a complexing agent, the isotope separation is higher. The separation factor is calculated to be a = 1 + epsilon = 1.011 for 40 Ca/ 48 Ca without complexing agent or with cryptand and a = 1.015 in the system with cryptand. For 40 Ca/ 44 Ca the epsilon-value is smaller by nearly a factor of two. These separation factors are the highest which are determined in chemical systems for calcium isotopes. (orig.)

  8. Transcriptome Wide Identification and Validation of Calcium Sensor Gene Family in the Developing Spikes of Finger Millet Genotypes for Elucidating Its Role in Grain Calcium Accumulation (United States)

    Singh, Uma M.; Chandra, Muktesh; Shankhdhar, Shailesh C.; Kumar, Anil


    Background In finger millet, calcium is one of the important and abundant mineral elements. The molecular mechanisms involved in calcium accumulation in plants remains poorly understood. Transcriptome sequencing of genetically diverse genotypes of finger millet differing in grain calcium content will help in understanding the trait. Principal Finding In this study, the transcriptome sequencing of spike tissues of two genotypes of finger millet differing in their grain calcium content, were performed for the first time. Out of 109,218 contigs, 78 contigs in case of GP-1 (Low Ca genotype) and out of 120,130 contigs 76 contigs in case of GP-45 (High Ca genotype), were identified as calcium sensor genes. Through in silico analysis all 82 unique calcium sensor genes were classified into eight calcium sensor gene family viz., CaM & CaMLs, CBLs, CIPKs, CRKs, PEPRKs, CDPKs, CaMKs and CCaMK. Out of 82 genes, 12 were found diverse from the rice orthologs. The differential expression analysis on the basis of FPKM value resulted in 24 genes highly expressed in GP-45 and 11 genes highly expressed in GP-1. Ten of the 35 differentially expressed genes could be assigned to three documented pathways involved mainly in stress responses. Furthermore, validation of selected calcium sensor responder genes was also performed by qPCR, in developing spikes of both genotypes grown on different concentration of exogenous calcium. Conclusion Through de novo transcriptome data assembly and analysis, we reported the comprehensive identification and functional characterization of calcium sensor gene family. The calcium sensor gene family identified and characterized in this study will facilitate in understanding the molecular basis of calcium accumulation and development of calcium biofortified crops. Moreover, this study also supported that identification and characterization of gene family through Illumina paired-end sequencing is a potential tool for generating the genomic information of

  9. Transcriptome wide identification and validation of calcium sensor gene family in the developing spikes of finger millet genotypes for elucidating its role in grain calcium accumulation.

    Directory of Open Access Journals (Sweden)

    Uma M Singh

    Full Text Available BACKGROUND: In finger millet, calcium is one of the important and abundant mineral elements. The molecular mechanisms involved in calcium accumulation in plants remains poorly understood. Transcriptome sequencing of genetically diverse genotypes of finger millet differing in grain calcium content will help in understanding the trait. PRINCIPAL FINDING: In this study, the transcriptome sequencing of spike tissues of two genotypes of finger millet differing in their grain calcium content, were performed for the first time. Out of 109,218 contigs, 78 contigs in case of GP-1 (Low Ca genotype and out of 120,130 contigs 76 contigs in case of GP-45 (High Ca genotype, were identified as calcium sensor genes. Through in silico analysis all 82 unique calcium sensor genes were classified into eight calcium sensor gene family viz., CaM & CaMLs, CBLs, CIPKs, CRKs, PEPRKs, CDPKs, CaMKs and CCaMK. Out of 82 genes, 12 were found diverse from the rice orthologs. The differential expression analysis on the basis of FPKM value resulted in 24 genes highly expressed in GP-45 and 11 genes highly expressed in GP-1. Ten of the 35 differentially expressed genes could be assigned to three documented pathways involved mainly in stress responses. Furthermore, validation of selected calcium sensor responder genes was also performed by qPCR, in developing spikes of both genotypes grown on different concentration of exogenous calcium. CONCLUSION: Through de novo transcriptome data assembly and analysis, we reported the comprehensive identification and functional characterization of calcium sensor gene family. The calcium sensor gene family identified and characterized in this study will facilitate in understanding the molecular basis of calcium accumulation and development of calcium biofortified crops. Moreover, this study also supported that identification and characterization of gene family through Illumina paired-end sequencing is a potential tool for generating the

  10. Generation of a Homozygous Transgenic Rat Strain Stably Expressing a Calcium Sensor Protein for Direct Examination of Calcium Signaling. (United States)

    Szebényi, Kornélia; Füredi, András; Kolacsek, Orsolya; Pergel, Enikő; Bősze, Zsuzsanna; Bender, Balázs; Vajdovich, Péter; Tóvári, József; Homolya, László; Szakács, Gergely; Héja, László; Enyedi, Ágnes; Sarkadi, Balázs; Apáti, Ágota; Orbán, Tamás I


    In drug discovery, prediction of selectivity and toxicity require the evaluation of cellular calcium homeostasis. The rat is a preferred laboratory animal for pharmacology and toxicology studies, while currently no calcium indicator protein expressing rat model is available. We established a transgenic rat strain stably expressing the GCaMP2 fluorescent calcium sensor by a transposon-based methodology. Zygotes were co-injected with mRNA of transposase and a CAG-GCaMP2 expressing construct, and animals with one transgene copy were pre-selected by measuring fluorescence in blood cells. A homozygous rat strain was generated with high sensor protein expression in the heart, kidney, liver, and blood cells. No pathological alterations were found in these animals, and fluorescence measurements in cardiac tissue slices and primary cultures demonstrated the applicability of this system for studying calcium signaling. We show here that the GCaMP2 expressing rat cardiomyocytes allow the prediction of cardiotoxic drug side-effects, and provide evidence for the role of Na(+)/Ca(2+) exchanger and its beneficial pharmacological modulation in cardiac reperfusion. Our data indicate that drug-induced alterations and pathological processes can be followed by using this rat model, suggesting that transgenic rats expressing a calcium-sensitive protein provide a valuable system for pharmacological and toxicological studies.

  11. Calcium regulation in frog peripheral nerve by the blood-nerve barrier

    International Nuclear Information System (INIS)

    Wadhwani, K.C.


    The objectives of this research were: (a) to investigate the characteristics of calcium transport across the perineurium and the endoneurial capillaries, and (b) to gain a better understanding of the extent of calcium homeostasis in the endoneurial space. To study the nature of calcium transport across the perineurium, the flux of radiotracer 45 Ca was measured through the perineurial cylinder, isolated from the frog sciatic nerve, and through the perineurium into the nerve in situ. To study the nature of calcium transport across the endoneurial capillaries, the permeability-surface area product (PA) of 45 Ca was determined as a function of the calcium concentration in the blood. To study calcium homeostasis, the calcium content of the frog sciatic nerve was determined as a function of chronic changes in plasma [Ca

  12. Calcium extraction from brine water and seawater using oxalic acid (United States)

    Natasha, Nadia Chrisayu; Lalasari, Latifa Hanum


    Calcium can be extracted not only from rocks but also from natural liquor such as seawater and brine water. In order to extract the calcium from seawater and brine water, oxalic acid was used in this research. Effect of variations of the volume of the oxalic acid at a constant concentration in seawater and brine water to produce calcium was investigated. The concentration of oxalic acid was 100 g/l and the variations of its volume were 2 ml, 4 ml, 6 ml, 8 ml, 10 ml, 20 ml, 30 ml, 40 ml, and 50 ml. The used seawater and brine water were firstly evaporated from 100 ml into 50 ml and then the oxalic acid was added into them with mixing to produce the calcium precipitates. The precipitates were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) and the filtrates were analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES). The SEM analysis showed that the precipitates from brine water were consisted of only calcium compound while from seawater sodium one was also found along with calcium compound. The XRD analysis showed that the calcium was present in the form of calcium oxalate for both seawater and brine water. The ICP-OES analysis of the filtrate from seawater precipitation showed that the its calcium content was decreased from 826.20 ppm to 0.04 ppm while from brine water, it decreased from 170.06 ppm to 1.96 ppm. These results showed that both seawater and brine water have the potential to be a raw material for calcium production.

  13. Calcium-based biomaterials for diagnosis, treatment, and theranostics. (United States)

    Qi, Chao; Lin, Jing; Fu, Lian-Hua; Huang, Peng


    Calcium-based (CaXs) biomaterials including calcium phosphates, calcium carbonates, calcium silicate and calcium fluoride have been widely utilized in the biomedical field owing to their excellent biocompatibility and biodegradability. In recent years, CaXs biomaterials have been strategically integrated with imaging contrast agents and therapeutic agents for various molecular imaging modalities including fluorescence imaging, magnetic resonance imaging, ultrasound imaging or multimodal imaging, as well as for various therapeutic approaches including chemotherapy, gene therapy, hyperthermia therapy, photodynamic therapy, radiation therapy, or combination therapy, even imaging-guided therapy. Compared with other inorganic biomaterials such as silica-, carbon-, and gold-based biomaterials, CaXs biomaterials can dissolve into nontoxic ions and participate in the normal metabolism of organisms. Thus, they offer safer clinical solutions for disease theranostics. This review focuses on the state-of-the-art progress in CaXs biomaterials, which covers from their categories, characteristics and preparation methods to their bioapplications including diagnosis, treatment, and theranostics. Moreover, the current trends and key problems as well as the future prospects and challenges of CaXs biomaterials are also discussed at the end.

  14. Effect of ethionine on hepatic mitochondrial and microsomal calcium uptake

    International Nuclear Information System (INIS)

    Agarwal, A.K.; Zinermon, W.D.; Latoni, L.


    Ethionine, an ethyl analog of methionine, produces a variety of physiological and pathological effects in animals. These range from acute effects in the liver, kidney, pancreas, and other organs to liver carcinogenesis. Female rats when injected with ethionine exhibit a rapid decrease in hepatic adenosine triphosphate levels followed by a marked inhibition of RNA and protein synthesis and accumulation of triglycerides. Since calcium transport in mitochondria and microsomes is ATP dependent, it becomes interesting to find out if ethionine administration has any effect on subcellular calcium transport. Calcium has recently gained an increased controversy regarding its role in chemical induced lethal cell damage. Certain groups believe that influx of extracellular calcium across the damaged plasma membrane might actually mediate the irreversible damage to the cell, whereas according to other, entry of calcium into the cell is secondary to the damage. The present study was carried out to investigate the calcium [ 45 Ca] transport in mitochondria and microsomes following ethionine administration. The effect of carbon tetrachloride on calcium uptake in ethionine treated rats was also studied

  15. New Role of P/Q-type Voltage-gated Calcium Channels

    DEFF Research Database (Denmark)

    Hansen, Pernille B L


    Voltage-gated calcium channels are important for the depolarization-evoked contraction of vascular smooth muscle cells (SMCs), with L-type channels being the classical channel involved in this mechanism. However, it has been demonstrated that the CaV2.1 subunit, which encodes a neuronal isoform...... of the voltage-gated calcium channels (P/Q-type), is also expressed and contributes functionally to contraction of renal blood vessels in both mice and humans. Furthermore, preglomerular vascular SMCs and aortic SMCs coexpress L-, P-, and Q-type calcium channels within the same cell. Calcium channel blockers...... are widely used as pharmacological treatments. However, calcium channel antagonists vary in their selectivity for the various calcium channel subtypes, and the functional contribution from P/Q-type channels as compared with L-type should be considered. Confirming the presence of P/Q-type voltage...

  16. Yolk-Shell Porous Microspheres of Calcium Phosphate Prepared by Using Calcium L-Lactate and Adenosine 5'-Triphosphate Disodium Salt: Application in Protein/Drug Delivery. (United States)

    Ding, Guan-Jun; Zhu, Ying-Jie; Qi, Chao; Sun, Tuan-Wei; Wu, Jin; Chen, Feng


    A facile and environmentally friendly approach has been developed to prepare yolk-shell porous microspheres of calcium phosphate by using calcium L-lactate pentahydrate (CL) as the calcium source and adenosine 5'-triphosphate disodium salt (ATP) as the phosphate source through the microwave-assisted hydrothermal method. The effects of the concentration of CL, the microwave hydrothermal temperature, and the time on the morphology and crystal phase of the product are investigated. The possible formation mechanism of yolk-shell porous microspheres of calcium phosphate is proposed. Hemoglobin from bovine red cells (Hb) and ibuprofen (IBU) are used to explore the application potential of yolk-shell porous microspheres of calcium phosphate in protein/drug loading and delivery. The experimental results indicate that the as-prepared yolk-shell porous microspheres of calcium phosphate have relatively high protein/drug loading capacity, sustained protein/drug release, favorable pH-responsive release behavior, and a high biocompatibility in the cytotoxicity test. Therefore, the yolk-shell porous microspheres of calcium phosphate have promising applications in various biomedical fields such as protein/drug delivery. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. The influence of magnesium deficiency on calcium metabolism in the rat

    International Nuclear Information System (INIS)

    Larvor, P.; Labat, M.-L.


    Calcium metabolism was studied in magnesium-deficient rats with an isotopic technique. 45 Ca was injected intravenously and the blood calcium radioactivity curve was analyzed mathematically to compute the kinetics of calcium exchange in the whole body. No important change was noticed after a 10-day magnesium deficiency; there was a significant reduction of the ratio calcium pool/total calcium output from the pool (P/Vsub(T)). After a 20-day deficiency, a dramatic decrease in the two compartments of exchangeable calcium (-40%), and a less important decrease of Vsub(T)(-15%) was noted. Blood plasma urea level increased during magnesium deficiency, while urea urinary clearance remained

  18. Assay method for organic calcium antagonist drugs and a kit for such an assay

    International Nuclear Information System (INIS)

    Snyder, S. H.; Gould, R. J.


    A method for measuring the level of organic calcium antagonist drug in a body fluid comprises preparing a mixture of a radioactive calcium antagonist drug, a body fluid containing a calcium antagonist drug and a calcium antagonist receptor material, measuring the radioactivity of the radioactive calcium antagonist drug bound to said calcium antagonist receptor material and deriving the concentration of the calcium antagonist drug in the body fluid from a standard curve indicating the concentration of calcium antagonist drug versus inhibition of binding of said radioactive calcium antagonist drug to said receptor sites caused by the calcium antagonist drug in said body fluid. A kit for measuring the level of an organic calcium drug comprises a receptacle containing a radioactive calcium antagonist drug, a calcium antagonist receptor material and a standard amount of a nonradioactive calcium antagonist drug

  19. Effects of soaking and acidification on physicochemical properties of calcium-fortified rice. (United States)

    Sirisoontaralak, Porntip; Limboon, Pailin; Jatuwong, Sujitra; Chavanalikit, Arusa


    Calcium-fortified rice was prepared by soaking milled rice in calcium lactate solution, steaming and drying, and physicochemical properties were determined to evaluate effects of calcium concentration (0, 30, 50 g L(-1) ), soaking temperature (ambient temperature, 40 °C, 60 °C) and acidification. Calcium-fortified rice had less lightness. More total solid loss was observed, especially at high soaking temperature. Harder texture was detected with increased calcium concentration. Calcium fortification lowered pasting viscosity of milled rice. Panelists accepted all fortified rice; however, only rice soaked at 50 g L(-1) concentration could be claimed as a good source of calcium. Increasing of soaking temperature induced more penetration of calcium to rice kernels but calcium was lost more easily after washing. With addition of acetic acid to the soaking solution, enriched calcium content was comparable to that of high soaking temperature but with better retention after washing and calcium solubility was improved. Acid induced reduction of lightness and cooked rice hardness but increased total solid loss and pasting viscosity. Although the taste of acetic acid remained, panelists still accepted the fortified rice. Calcium-fortified rice (190.47-194.3 mg 100 g(-1) ) could be successfully produced by soaking milled rice in 50 g L(-1) calcium lactate solution at 40 °C or at ambient temperature with acidification. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  20. Zero Calcium Score as a Filter for Further Testing in Patients Admitted to the Coronary Care Unit with Chest Pain. (United States)

    Correia, Luis Cláudio Lemos; Esteves, Fábio P; Carvalhal, Manuela; Souza, Thiago Menezes Barbosa de; Sá, Nicole de; Correia, Vitor Calixto de Almeida; Alexandre, Felipe Kalil Beirão; Lopes, Fernanda; Ferreira, Felipe; Noya-Rabelo, Márcia


    The accuracy of zero coronary calcium score as a filter in patients with chest pain has been demonstrated at the emergency room and outpatient clinics, populations with low prevalence of coronary artery disease (CAD). To test the gatekeeping role of zero calcium score in patients with chest pain admitted to the coronary care unit (CCU), where the pretest probability of CAD is higher than that of other populations. Patients underwent computed tomography for calcium scoring, and obstructive CAD was defined by a minimum 70% stenosis on invasive angiography. In 146 patients studied, the prevalence of CAD was 41%. A zero calcium score was present in 35% of the patients. The sensitivity and specificity of zero calcium score yielded a negative likelihood ratio of 0.16. After logistic regression adjustment for pretest probability, zero calcium score was independently associated with lower odds of CAD (OR = 0.12, 95%CI = 0.04-0.36), increasing the area under the ROC curve of the clinical model from 0.76 to 0.82 (p = 0.006). Zero calcium score provided a net reclassification improvement of 0.20 (p = 0.0018) over the clinical model when using a pretest probability threshold of 10% for discharging without further testing. In patients with pretest probability zero calcium score had a negative predictive value of 95% (95%CI = 83%-99%), with a number needed to test of 2.1 for obtaining one additional discharge. Zero calcium score substantially reduces the pretest probability of obstructive CAD in patients admitted to the CCU with acute chest pain. (Arq Bras Cardiol. 2017; [online].ahead print, PP.0-0). A acurácia do escore de cálcio coronário zero como um filtro nos pacientes com dor torácica aguda tem sido demonstrada na sala de emergência e nos ambulatórios, populações com baixa prevalência de doença arterial coronariana (DAC). Testar o papel do escore de cálcio zero como filtro nos pacientes com dor torácica admitidos numa unidade coronariana intensiva (UCI), na

  1. C2-domain containing calcium sensors in neuroendocrine secretion

    DEFF Research Database (Denmark)

    Pinheiro, Paulo S; Houy, Sébastien; Sørensen, Jakob B


    The molecular mechanisms for calcium-triggered membrane fusion have long been sought for, and detailed models now exist that account for at least some of the functions of the many proteins involved in the process. Key players in the fusion reaction are a group of proteins that, upon binding...... to calcium, trigger the merger of cargo-filled vesicles with the plasma membrane. Low-affinity, fast-kinetics calcium sensors of the synaptotagmin family - especially synaptotagmin-1 and synaptotagmin-2 - are the main calcium sensors for fast exocytosis triggering in many cell types. Their functions extend...... beyond fusion triggering itself, having been implicated in the calcium-dependent vesicle recruitment during activity, docking of vesicles to the plasma membrane and priming, and even in post-fusion steps, such as fusion pore expansion and endocytosis. Furthermore, synaptotagmin diversity imparts distinct...

  2. Decay of 36K

    International Nuclear Information System (INIS)

    Fritts, M.J.


    36 K was produced via the 36 Ar(p, n) 36 K reaction. Measurement of 27 β + delayed γ rays associated with the decay of 36 K implied 10 new β + branches to energy levels in 36 Ar. Branching ratios and logft values are calculated for the β + branches. Restrictions on spin and parity assignments for the 36 Ar levels are given, as well as branching ratios for γ transitions from these levels. The half-life of 36 K is determined to be 344 +- 3 msec

  3. Prevention of nutritional rickets in Nigerian children with dietary calcium supplementation. (United States)

    Thacher, Tom D; Fischer, Philip R; Isichei, Christian O; Zoakah, Ayuba I; Pettifor, John M


    Nutritional rickets in Nigerian children usually results from dietary calcium insufficiency. Typical dietary calcium intakes in African children are about 200mg daily (approximately 20-28% of US RDAs for age). We sought to determine if rickets could be prevented with supplemental calcium or with an indigenous food rich in calcium. We enrolled Nigerian children aged 12 to 18months from three urban communities. Two communities were assigned calcium, either as calcium carbonate (400mg) or ground fish (529±109mg) daily, while children in all three communities received vitamin A (2500IU) daily as placebo. Serum markers of mineral homeostasis and forearm bone density (pDEXA) were measured and radiographs were obtained at enrollment and after 18months of supplementation. The overall prevalence of radiographic rickets at baseline was 1.2% and of vitamin D deficiency [serum 25(OH)DRickets developed in 1, 1, and 2 children assigned to the calcium tablet, ground fish, and control groups, respectively (approximate incidence 6.4/1000 children/year between 1 and 3years of age). Children who developed rickets in the calcium-supplemented groups had less than 50% adherence. Compared with the group that received no calcium supplementation, the groups that received calcium had a greater increase in areal bone density of the distal and proximal 1/3 radius and ulna over time (Prickets. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Bony integration of titanium implants with a novel bioactive calcium titanate (Ca4Ti3O10) surface treatment in a rabbit model. (United States)

    Haenle, Maximilian; Lindner, Tobias; Ellenrieder, Martin; Willfahrt, Manfred; Schell, Hanna; Mittelmeier, Wolfram; Bader, Rainer


    Nowadays total joint replacement is an indispensable component of modern medicine. The surfaces characteristics of cementless prostheses may be altered to achieve an accelerated and enduring bony integration. Classic surface coatings bear the risk of loosening or flaking from the implant body. This risk is excluded by the chemical conversion of the naturally existing TiO(2) surface layer into calcium titanate. The aim of this experimental animal study was to investigate the bony integration of implants with a new calcium titanate surface (Ca(4)Ti(3)O(10)) compared with a conventional standard Ti6Al4V surface. Cylindrical implants, made of titanium alloy (Ti6Al4V) were implanted in both lateral femoral condyles of New Zealand white rabbits. In each animal, an implant with and without surface treatment was inserted in a blinded manner. Animals were sacrificed after 4, 12, and 36 weeks, respectively. The axial pull-off forces were determined for 25 animals using a universal testing machine (Zwick Z010, Ulm, Germany). Furthermore, a histological analysis of the bony integration of the implants was performed in 12 specimens. In general, the pull-off forces for untreated and treated implants increased with longer survival times of the rabbits. No significant difference could be shown after 4 weeks between treated and untreated implants. After 12 weeks, the treated implants revealed a statistical significant higher pull-off force. After 36 weeks, the pull-off forces for treated and untreated implants aligned again. Titanium implants treated with calcium titanate, may offer an interesting and promising implant surface modification for endoprosthetic implants. They might lead to an accelerated osseointegration of total hip and knee replacements. Copyright © 2012 Wiley Periodicals, Inc.

  5. Characterization of calcium signals in human induced pluripotent stem cell-derived dentate gyrus neuronal progenitors and mature neurons, stably expressing an advanced calcium indicator protein. (United States)

    Vőfély, Gergő; Berecz, Tünde; Szabó, Eszter; Szebényi, Kornélia; Hathy, Edit; Orbán, Tamás I; Sarkadi, Balázs; Homolya, László; Marchetto, Maria C; Réthelyi, János M; Apáti, Ágota


    Pluripotent stem cell derived human neuronal progenitor cells (hPSC-NPCs) and their mature neuronal cell culture derivatives may efficiently be used for central nervous system (CNS) drug screening, including the investigation of ligand-induced calcium signalization. We have established hippocampal NPC cultures derived from human induced PSCs, which were previously generated by non-integrating Sendai virus reprogramming. Using established protocols these NPCs were differentiated into hippocampal dentate gyrus neurons. In order to study calcium signaling without the need of dye loading, we have stably expressed an advanced calcium indicator protein (GCaMP6fast) in the NPCs using the Sleeping Beauty transposon system. We observed no significant effects of the long-term GCaMP6 expression on NPC morphology, gene expression pattern or neural differentiation capacity. In order to compare the functional properties of GCaMP6-expressing neural cells and the corresponding parental cells loaded with calcium indicator dye Fluo-4, a detailed characterization of calcium signals was performed. We found that the calcium signals induced by ATP, glutamate, LPA, or proteases - were similar in these two systems. Moreover, the presence of the calcium indicator protein allowed for a sensitive, repeatable detection of changes in calcium signaling during the process of neurogenesis and neuronal maturation. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. 40 CFR 415.50 - Applicability; description of the calcium oxide production subcategory. (United States)


    ... calcium oxide production subcategory. 415.50 Section 415.50 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Oxide Production Subcategory § 415.50 Applicability; description of the calcium... the production of calcium oxide. ...

  7. [Association between dietary calcium/dairy intakes and overweight/obesity]. (United States)

    Chen, Yanrong; Liu, Yan; Xue, Hongmei; Bao, Yuxin; Luo, Jiao; Tian, Guo; Cheng, Guo


    To investigate the intakes of dietary calcium/dairy and the current prevalence of overweight and obesity among children and adolescents aged 7-15 in Longquanyi District, Chengdu, and to explore the association of dietary calcium and dairy intake with overweight/obesity. 1738 children and adolescents were recruited in the cross-sectional study using cluster random sampling method. Information on dietary calcium and dairy intakes was collected using 24-hour dietary recall and food frequency questionnaire (FFQ). Height, weight and waist circumference were measured to calculate body mass index (BMI)/waist-to-height ratio (WHtR) and body mass index standard deviation (BMI SDS). Overweight/obesity was defined based on the criteria of Working Group on Obesity in China (WGOC). Participants were grouped into 3 categories indicating lower, moderate and higher intakes of dietary calcium and dairy, respectively. The association of dietary calcium and dairy consumption with (BMI SDS) /WHtR and the prevalence of overweight/obesity was analyzed after being stratified by gender and age. The prevalence of overweight/obesity in boys and girls were 11.92%/7.04% and 8.04%/6.30%, respectively. The intake of dietary calcium and dairy in girls were much higher than that in boys (P obesity in boys, however the associations were inconsistent among different age groups. Associations between consumption of calcium, dairy and overweight/obesity were not found among girls.

  8. A Single Nucleotide Polymorphism (rs4236480 in TRPV5 Calcium Channel Gene Is Associated with Stone Multiplicity in Calcium Nephrolithiasis Patients

    Directory of Open Access Journals (Sweden)

    Anas Khaleel


    Full Text Available Nephrolithiasis is characterized by calcification of stones in the kidneys from an unknown cause. Animal models demonstrated the functional roles of the transient receptor potential vanilloid member 5 (TRPV5 gene in calcium renal reabsorption and hypercalciuria. Therefore, TRPV5 was suggested to be involved in calcium homeostasis. However, whether genetic polymorphisms of TRPV5 are associated with kidney stone multiplicity or recurrence is unclear. In this study, 365 Taiwanese kidney-stone patients were recruited. Both biochemical data and DNA samples were collected. Genotyping was performed by a TaqMan allelic discrimination assay. We found that a TRPV5 polymorphism (rs4236480 was observed to be associated with stone multiplicity of calcium nephrolithiasis, as the risk of stone multiplicity was higher in patients with the TT+CT genotype than in patients with the CC genotype (p=0.0271. In summary, despite the complexity of nephrolithiasis and the potential association of numerous calcium homeostatic absorption/reabsorption factors, TRPV5 plays an important role in the pathogenesis of calcium nephrolithiasis.

  9. Anodic and cathodic reactions in molten calcium chloride

    International Nuclear Information System (INIS)

    Fray, D.J.


    Calcium chloride is a very interesting electrolyte in that it is available, virtually free, in high purity form as a waste product from the chemical industry. It has a very large solubility for oxide ions, far greater than many alkali halides and other divalent halides and has the same toxicity as sodium chloride and also a very high solubility in water. Intuitively, on the passage of current, it is expected that calcium would be deposited at the cathode and chlorine would evolve at the anode. However, if calcium oxide is added to the melt, it is possible to deposit calcium and evolve oxygen containing gases at the anode, making the process far less polluting than when chlorine is evolved. This process is discussed in terms of the addition of calcium to molten lead. Furthermore, these reactions can be altered dramatically depending upon the electrode materials and the other ions dissolved in the calcium chloride. As calcium is only deposited at very negative cathodic potentials, there are several interesting cathodic reactions that can occur and these include the decomposition of the carbonate ion and the ionization of oxygen, sulphur, selenium and tellurium. For example, if an oxide is used as the cathode in molten calcium chloride, the favoured reaction is shown to be the ionization of oxygen O + 2e - → O 2- rather than Ca 2+ + 2 e- → Ca. The oxygen ions dissolve in the salt leaving the metal behind, and this leads to the interesting hypothesis that metal oxides can be reduced directly to the metal purely by the use of electrons. Examples are given for the reduction of titanium dioxide, zirconium dioxide, chromium oxide and niobium oxide and by mixing oxide powders together and reducing the mixed compact, alloys and intermetallic compounds are formed. Preliminary calculations indicate that this new process should be much cheaper than conventional metallothermic reduction for these elements. (author)

  10. Calcium and Vitamin D: Important at Every Age (United States)

    ... need, see the Recommended Calcium Intakes (in milligrams) chart below. Recommended Calcium Intakes Life-stage group mg/ ... Child Health and Human Development National Institute of Dental and Craniofacial Research National Institute of Diabetes and ...

  11. Calcium Supplements: A Risk Factor for Heart Attack? (United States)

    ... factor for heart attack? I've read that calcium supplements may increase the risk of heart attack. ... D. Some doctors think it's possible that taking calcium supplements may increase your risk of a heart ...

  12. ALG-2, a multifunctional calcium binding protein?

    DEFF Research Database (Denmark)

    Tarabykina, Svetlana; Mollerup, Jens; Winding Gojkovic, P.


    ALG-2 was originally discovered as a pro-apoptotic protein in a genetic screen. Due to its ability to bind calcium with high affinity it was postulated to provide a link between the known effect of calcium in programmed cell death and the molecular death execution machinery. This review article...

  13. Elements from chlorine to calcium nuclear reactions

    CERN Document Server

    Kunz, Wunibald


    Nuclear Tables: Part II Nuclear Reactions, Volume 3: The Elements from Chlorine to Calcium contains tabulations of the nuclear reaction values of elements chlorine, argon, potassium, and calcium. These tabulations provide the calculated Q-values of the elements and their isotopes. This book will be of value to general chemistry researchers.

  14. 43. Calmodulin regulating calcium sensitivity of Na channels

    Directory of Open Access Journals (Sweden)

    R. Vegiraju


    Full Text Available By extrapolating information from existing research and observing previous assumptions regarding the structure of the Na Channel, this experiment was conducted under the hypothesis that the Na Channel is in part regulated by the calmodulin protein, as a result proving calcium sensitivity of the Na Channel. Furthermore, we assume that there is a one to one stoichiometry between the Na Channel and the Calmodulin. There has been extensive research into the functionality and structure of sodium ion channels (Na channels, as several diseases are associated with the lack of regulation of sodium ions, that is caused by the disfunction of these Na channels. However, one highly controversial matter in the field is the importance of the protein calmodulin (CaM and calcium in Na channel function. Calmodulin is a protein that is well known for its role as a calcium binding messenger protein, and that association is believed to play an indirect role in regulating the Na channel through the Na channel’s supposed calcium sensitivity. While there are proponents for both sides, there has been relatively little research that provides strong evidence for either case. In this experiment, the effect of calmodulin on NaV 1.5 is tested by preparing a set of cardiac cells (of the human specie with the NaV 1.5 C-Termini and CaM protein, which were then to be placed in solutions with varying concentrations of calcium. We took special care to test multiple concentrations of calcium, as previous studies have tested very low concentrations, with Manu Ben-Johny’s team from the John Hopkins laboratory in particular testing up to a meager 50 micromolar, despite producing a well-respected paper (By comparison, the average Na channel can naturally sustain a concentration of almost 1-2 millimolar and on some occasions, reaching even higher concentrations. After using light scattering and observing the signals given off by the calcium interacting with these Nav1.5/Ca

  15. Transfected parvalbumin alters calcium homeostasis in teratocarcinoma PCC7 cells

    DEFF Research Database (Denmark)

    Müller, B K; Kabos, P; Belhage, B


    Indirect evidence supports a protective role of some EF-hand calcium-binding proteins against calcium-induced neurotoxicity. Little is known about how these proteins influence cytosolic calcium levels. After cloning the parvalbumin cDNA into an expression vector, teratocarcinoma cells (PCC7) were...

  16. Protection of Dentate Hilar Cells from Prolonged Stimulation by Intracellular Calcium Chelation (United States)

    Scharfman, Helen E.; Schwartzkroin, Philip A.


    Prolonged afferent stimulation of the rat dentate gyrus in vivo leads to degeneration only of those cells that lack immunoreactivity for the calcium binding proteins parvalbumin and calbindin. In order to test the hypothesis that calcium binding proteins protect against the effects of prolonged stimulation, intracellular recordings were made in hippocampal slices from cells that lack immunoreactivity for calcium binding proteins. Calcium binding protein--negative cells showed electrophysiological signs of deterioration during prolonged stimulation; cells containing calcium binding protein did not. When neurons without calcium binding proteins were impaled with microelectrodes containing the calcium chelator BAPTA, and BAPTA was allowed to diffuse into the cells, these cells showed no deterioration. These results indicate that, in a complex tissue of the central nervous system, an activity-induced increase in intracellular calcium can trigger processes leading to cell deterioration, and that increasing the calcium binding capacity of a cell decreases its vulnerability to damage.

  17. Kit W-sh Mutation Prevents Cancellous Bone Loss during Calcium Deprivation. (United States)

    Lotinun, Sutada; Suwanwela, Jaijam; Poolthong, Suchit; Baron, Roland


    Calcium is essential for normal bone growth and development. Inadequate calcium intake increases the risk of osteoporosis and fractures. Kit ligand/c-Kit signaling plays an important role in regulating bone homeostasis. Mice with c-Kit mutations are osteopenic. The present study aimed to investigate whether impairment of or reduction in c-Kit signaling affects bone turnover during calcium deprivation. Three-week-old male WBB6F1/J-Kit W /Kit W-v /J (W/W v ) mice with c-Kit point mutation, Kit W-sh /HNihrJaeBsmJ (W sh /W sh ) mice with an inversion mutation in the regulatory elements upstream of the c-Kit promoter region, and their wild-type controls (WT) were fed either a normal (0.6% calcium) or a low calcium diet (0.02% calcium) for 3 weeks. μCT analysis indicated that both mutants fed normal calcium diet had significantly decreased cortical thickness and cancellous bone volume compared to WT. The low calcium diet resulted in a comparable reduction in cortical bone volume and cortical thickness in the W/W v and W sh /W sh mice, and their corresponding controls. As expected, the low calcium diet induced cancellous bone loss in the W/W v mice. In contrast, W sh /W sh cancellous bone did not respond to this diet. This c-Kit mutation prevented cancellous bone loss by antagonizing the low calcium diet-induced increase in osteoblast and osteoclast numbers in the W sh /W sh mice. Gene expression profiling showed that calcium deficiency increased Osx, Ocn, Alp, type I collagen, c-Fms, M-CSF, and RANKL/OPG mRNA expression in controls; however, the W sh mutation suppressed these effects. Our findings indicate that although calcium restriction increased bone turnover, leading to osteopenia, the decreased c-Kit expression levels in the W sh /W sh mice prevented the low calcium diet-induced increase in cancellous bone turnover and bone loss but not the cortical bone loss.

  18. X-Ray Absorption Near-Edge Structure (XANES) of Calcium L3,2 Edges of Various Calcium Compounds and X-Ray Excited Optical Luminescence (XEOL) Studies of Luminescent Calcium Compounds

    International Nuclear Information System (INIS)

    Ko, J. Y. Peter; Zhou Xingtai; Sham, T.-K.; Heigl, Franziskus; Regier, Tom; Blyth, Robert


    X-ray absorption at calcium L3,2 edges of various calcium compounds were measured using a high resolution Spherical Grating Monochromator (SGM) at the Canadian Light Source (CLS). We observe that each compound has its unique fine structure of L3,2 edges. This uniqueness is due to differences in local structure of compounds. We also performed (X-ray Excited Optical Luminescence) XEOL of selected luminescent calcium compounds to investigate their optical properties. XEOL is a photon-in-photon-out technique in which the optical luminescence that is excited by tunable x-rays from a synchrotron light source is monitored. Depending on excitation energy of the x-ray, relative intensities of luminescence peaks vary. Recent findings of the results will be presented here

  19. Calcium signalling silencing in atrial fibrillation. (United States)

    Greiser, Maura


    Subcellular calcium signalling silencing is a novel and distinct cellular and molecular adaptive response to rapid cardiac activation. Calcium signalling silencing develops during short-term sustained rapid atrial activation as seen clinically during paroxysmal atrial fibrillation (AF). It is the first 'anti-arrhythmic' adaptive response in the setting of AF and appears to counteract the maladaptive changes that lead to intracellular Ca 2+ signalling instability and Ca 2+ -based arrhythmogenicity. Calcium signalling silencing results in a failed propagation of the [Ca 2+ ] i signal to the myocyte centre both in patients with AF and in a rabbit model. This adaptive mechanism leads to a substantial reduction in the expression levels of calcium release channels (ryanodine receptors, RyR2) in the sarcoplasmic reticulum, and the frequency of Ca 2+ sparks and arrhythmogenic Ca 2+ waves remains low. Less Ca 2+ release per [Ca 2+ ] i transient, increased fast Ca 2+ buffering strength, shortened action potentials and reduced L-type Ca 2+ current contribute to a substantial reduction of intracellular [Na + ]. These features of Ca 2+ signalling silencing are distinct and in contrast to the changes attributed to Ca 2+ -based arrhythmogenicity. Some features of Ca 2+ signalling silencing prevail in human AF suggesting that the Ca 2+ signalling 'phenotype' in AF is a sum of Ca 2+ stabilizing (Ca 2+ signalling silencing) and Ca 2+ destabilizing (arrhythmogenic unstable Ca 2+ signalling) factors. Calcium signalling silencing is a part of the mechanisms that contribute to the natural progression of AF and may limit the role of Ca 2+ -based arrhythmogenicity after the onset of AF. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

  20. Inhibition of parathyroid hormone release by maitotoxin, a calcium channel activator

    International Nuclear Information System (INIS)

    Fitzpatrick, L.A.; Yasumoto, T.; Aurbach, G.D.


    Maitotoxin, a toxin derived from a marine dinoflagellate, is a potent activator of voltage-sensitive calcium channels. To further test the hypothesis that inhibition of PTH secretion by calcium is mediated via a calcium channel we studied the effect of maitotoxin on dispersed bovine parathyroid cells. Maitotoxin inhibited PTH release in a dose-dependent fashion, and inhibition was maximal at 1 ng/ml. Chelation of extracellular calcium by EGTA blocked the inhibition of PTH by maitotoxin. Maitotoxin enhanced the effects of the dihydropyridine calcium channel agonist (+)202-791 and increased the rate of radiocalcium uptake in parathyroid cells. Pertussis toxin, which ADP-ribosylates and inactivates a guanine nucleotide regulatory protein that interacts with calcium channels in the parathyroid cell, did not affect the inhibition of PTH secretion by maitotoxin. Maitotoxin, by its action on calcium channels allows entry of extracellular calcium and inhibits PTH release. Our results suggest that calcium channels are involved in the release of PTH. Inhibition of PTH release by maitotoxin is not sensitive to pertussis toxin, suggesting that maitotoxin may act distal to the site interacting with a guanine nucleotide regulatory protein, or maitotoxin could interact with other ions or second messengers to inhibit PTH release